关于足细胞中铁代谢和铁死亡的研究

Podocytes, specialized epithelial cells that envelop the glomerular capillaries, play a pivotal role in maintaining renal health. The current description and quantification of features on pathology slides are limited, prompting the need for innovative solutions to comprehensively assess diverse phenotypic attributes within Whole Slide Images (WSIs). In particular, understanding the morphological characteristics of podocytes, terminally differentiated glomerular epithelial cells, is crucial for studying glomerular injury. This paper introduces the Spatial Pathomics Toolkit (SPT) and applies it to podocyte pathomics. The SPT consists of three main components: (1) instance object segmentation, enabling precise identification of podocyte nuclei; (2) pathomics feature generation, extracting a comprehensive array of quantitative features from the identified nuclei; and (3) robust statistical analyses, facilitating a comprehensive exploration of spatial relationships between morphological and spatial transcriptomics features.The SPT successfully extracted and analyzed morphological and textural features from podocyte nuclei, revealing a multitude of podocyte morphomic features through statistical analysis. Additionally, we demonstrated the SPT's ability to unravel spatial information inherent to podocyte distribution, shedding light on spatial patterns associated with glomerular injury. By disseminating the SPT, our goal is to provide the research community with a powerful and user-friendly resource that advances cellular spatial pathomics in renal pathology. The implementation and its complete source code of the toolkit are made openly accessible at https://github.com/hrlblab/spatial_pathomics.

Ferroptosis, a regulated form of cell death driven by oxidative stress and lipid peroxidation, has emerged as a pivotal research focus with implications across various cellular contexts. In this study, we employed a multifaceted approach, integrating label-free Raman spectroscopy and microfluidics to study the mechanisms underpinning ferroptosis. Our investigations included the ferroptosis initiation based on the changes in the lipid Raman band at 1436 cm-1 under different cellular states, the generation of reactive oxygen species (ROS), lipid peroxidation, DNA damage/repair, and mitochondrial dysfunction. Importantly, our work highlighted the dynamic role of vital cellular components, such as NADPH, ferredoxin clusters, and key genes like GPX-4, VDAC2, and NRF2, as they collectively influenced cellular responses to redox imbalance and oxidative stress. Quantum mechanical (QM) and molecular docking simulations (MD) provided further evidence of interactions between the ferredoxin (containing 4Fe-4S clusters), NADPH and ROS which led to the production of reactive Fe species in the cells. As such, our approach offered a real-time, multidimensional perspective on ferroptosis, surpassing traditional biological methods, and providing valuable insights for therapeutic interventions in diverse biomedical contexts.

Background: Automated podocyte foot process quantification is vital for kidney research, but the established "Automatic Morphological Analysis of Podocytes" (AMAP) method is hindered by high computational demands, a lack of a user interface, and Linux dependency. We developed AMAP-APP, a cross-platform desktop application designed to overcome these barriers. Methods: AMAP-APP optimizes efficiency by replacing intensive instance segmentation with classic image processing while retaining the original semantic segmentation model. It introduces a refined Region of Interest (ROI) algorithm to improve precision. Validation involved 365 mouse and human images (STED and confocal), benchmarking performance against the original AMAP via Pearson correlation and Two One-Sided T-tests (TOST). Results: AMAP-APP achieved a 147-fold increase in processing speed on consumer hardware. Morphometric outputs (area, perimeter, circularity, and slit diaphragm density) showed high correlation (r>0.90) and statistical equivalence (TOST P<0.05) to the original method. Additionally, the new ROI algorithm demonstrated superior accuracy compared to the original, showing reduced deviation from manual delineations. Conclusion: AMAP-APP democratizes deep learning-based podocyte morphometry. By eliminating the need for high-performance computing clusters and providing a user-friendly interface for Windows, macOS, and Linux, it enables widespread adoption in nephrology research and potential clinical diagnostics.

Ferroptosis is a form of cell death discovered in recent years, induced by excessive peroxidation of phospholipids. Glutathione peroxidase 4 (GPx4) is an intracellular enzyme that can repair the peroxidized phospholipids on membranes, thus regulating ferroptosis. By combining multiscale molecular dynamics (MD) simulations and experimental assays, we investigate the binding mechanisms of GPx4 on membranes. Using coarse-grained MD simulations, we found that L130 and its adjacent residues on GPx4 can form a stable and unique binding interface with PE/PS-rich and peroxidized membranes. Subsequent all-atom MD simulations verified the stability of the binding interface. The critical residue on the interface, L130, was inserted deeply into the membrane as a hydrophobic anchor and guided the reaction center toward the membrane surface. Enzyme activity assays and in vitro cell experiments showed that mutations of L130 resulted in weaker activities of the enzyme, probably caused by non-functional binding modes of GPx4 on membranes, as revealed by in silico simulations. This study highlights the crucial role of the hydrophobic residue, L130, in the proper anchoring of GPx4 on membranes, the first step of its membrane-repairing function.

Multi-class cell segmentation in high-resolution Giga-pixel whole slide images (WSI) is critical for various clinical applications. Training such an AI model typically requires labor-intensive pixel-wise manual annotation from experienced domain experts (e.g., pathologists). Moreover, such annotation is error-prone when differentiating fine-grained cell types (e.g., podocyte and mesangial cells) via the naked human eye. In this study, we assess the feasibility of democratizing pathological AI deployment by only using lay annotators (annotators without medical domain knowledge). The contribution of this paper is threefold: (1) We proposed a molecular-empowered learning scheme for multi-class cell segmentation using partial labels from lay annotators; (2) The proposed method integrated Giga-pixel level molecular-morphology cross-modality registration, molecular-informed annotation, and molecular-oriented segmentation model, so as to achieve significantly superior performance via 3 lay annotators as compared with 2 experienced pathologists; (3) A deep corrective learning (learning with imperfect label) method is proposed to further improve the segmentation performance using partially annotated noisy data. From the experimental results, our learning method achieved F1 = 0.8496 using molecular-informed annotations from lay annotators, which is better than conventional morphology-based annotations (F1 = 0.7015) from experienced pathologists. Our method democratizes the development of a pathological segmentation deep model to the lay annotator level, which consequently scales up the learning process similar to a non-medical computer vision task. The official implementation and cell annotations are publicly available at https://github.com/hrlblab/MolecularEL.

Understanding the anatomy of renal pathology is crucial for advancing disease diagnostics, treatment evaluation, and clinical research. The complex kidney system comprises various components across multiple levels, including regions (cortex, medulla), functional units (glomeruli, tubules), and cells (podocytes, mesangial cells in glomerulus). Prior studies have predominantly overlooked the intricate spatial interrelations among objects from clinical knowledge. In this research, we introduce a novel universal proposition learning approach, called panoramic renal pathology segmentation (PrPSeg), designed to segment comprehensively panoramic structures within kidney by integrating extensive knowledge of kidney anatomy. In this paper, we propose (1) the design of a comprehensive universal proposition matrix for renal pathology, facilitating the incorporation of classification and spatial relationships into the segmentation process; (2) a token-based dynamic head single network architecture, with the improvement of the partial label image segmentation and capability for future data enlargement; and (3) an anatomy loss function, quantifying the inter-object relationships across the kidney.

The automated analysis of medical images is currently limited by technical and biological noise and bias. The same source tissue can be represented by vastly different images if the image acquisition or processing protocols vary. For an image analysis pipeline, it is crucial to compensate such biases to avoid misinterpretations. Here, we evaluate, compare, and improve existing generative model architectures to overcome domain shifts for immunofluorescence (IF) and Hematoxylin and Eosin (H&E) stained microscopy images. To determine the performance of the generative models, the original and transformed images were segmented or classified by deep neural networks that were trained only on images of the target bias. In the scope of our analysis, U-Net cycleGANs trained with an additional identity and an MS-SSIM-based loss and Fixed-Point GANs trained with an additional structure loss led to the best results for the IF and H&E stained samples, respectively. Adapting the bias of the samples significantly improved the pixel-level segmentation for human kidney glomeruli and podocytes and improved the classification accuracy for human prostate biopsies by up to 14%.

Segmenting glomerular intraglomerular tissue and lesions traditionally depends on detailed morphological evaluations by expert nephropathologists, a labor-intensive process susceptible to interobserver variability. Our group previously developed the Glo-In-One toolkit for integrated detection and segmentation of glomeruli. In this study, we leverage the Glo-In-One toolkit to version 2 with fine-grained segmentation capabilities, curating 14 distinct labels for tissue regions, cells, and lesions across a dataset of 23,529 annotated glomeruli across human and mouse histopathology data. To our knowledge, this dataset is among the largest of its kind to date.In this study, we present a single dynamic head deep learning architecture designed to segment 14 classes within partially labeled images of human and mouse pathology data. Our model was trained using a training set derived from 368 annotated kidney whole-slide images (WSIs) to identify 5 key intraglomerular tissues covering Bowman's capsule, glomerular tuft, mesangium, mesangial cells, and podocytes. Additionally, the network segments 9 glomerular lesion classes including adhesion, capsular drop, global sclerosis, hyalinosis, mesangial lysis, microaneurysm, nodular sclerosis, mesangial expansion, and segmental sclerosis. The glomerulus segmentation model achieved a decent performance compared with baselines, and achieved a 76.5 % average Dice Similarity Coefficient (DSC). Additional, transfer learning from rodent to human for glomerular lesion segmentation model has enhanced the average segmentation accuracy across different types of lesions by more than 3 %, as measured by Dice scores. The Glo-In-One-v2 model and trained weight have been made publicly available at https: //github.com/hrlblab/Glo-In-One_v2.

Precise identification of multiple cell classes in high-resolution Giga-pixel whole slide imaging (WSI) is critical for various clinical scenarios. Building an AI model for this purpose typically requires pixel-level annotations, which are often unscalable and must be done by skilled domain experts (e.g., pathologists). However, these annotations can be prone to errors, especially when distinguishing between intricate cell types (e.g., podocytes and mesangial cells) using only visual inspection. Interestingly, a recent study showed that lay annotators, when using extra immunofluorescence (IF) images for reference (referred to as molecular-empowered learning), can sometimes outperform domain experts in labeling. Despite this, the resource-intensive task of manual delineation remains a necessity during the annotation process. In this paper, we explore the potential of bypassing pixel-level delineation by employing the recent segment anything model (SAM) on weak box annotation in a zero-shot learning approach. Specifically, we harness SAM's ability to produce pixel-level annotations from box annotations and utilize these SAM-generated labels to train a segmentation model. Our findings show that the proposed SAM-assisted molecular-empowered learning (SAM-L) can diminish the labeling efforts for lay annotators by only requiring weak box annotations. This is achieved without compromising annotation accuracy or the performance of the deep learning-based segmentation. This research represents a significant advancement in democratizing the annotation process for training pathological image segmentation, relying solely on non-expert annotators.

This study describes the distribution of intravenously injected polyacrylic acid (PAA) coated γ-Fe2O3 NPs (10 mg kg-1) at the organ, cellular and subcellular levels in healthy BALB/cJ mice and in parallel addresses the effects of NP injection on kidney function, blood pressure and vascular contractility. Magnetic resonance imaging (MRI) and transmission electron microscopy (TEM) showed accumulation of NPs in the liver within 1h after intravenous infusion, accommodated by intracellular uptake in endothelial and Kupffer cells with subsequent intracellular uptake in renal cells, particularly the cytoplasm of the proximal tubule, in podocytes and mesangial cells. The renofunctional effects of NPs were evaluated by arterial acid-base status and measurements of glomerular filtration rate (GFR) after instrumentation with chronically indwelling catheters. Arterial pH was 7.46 and 7.41 in mice 0.5 h after injections of saline or NP, and did not change over the next 12h. In addition, the injections of NP did not affect arterial PCO2 or [HCO3-] either. Twenty-four and 96h after NP injections, the GFR averaged 11.0 and 13.0 ml min-1 g-1, respectively, values which were statistically comparable with controls (14.0 and 14.0 ml min-1 g-1). Mean arterial blood pressure (MAP) decreased 12-24h after NP injections (111 vs 123 min-1) associated with a decreased contractility of small mesenteric arteries revealed by myography to characterise endothelial function. In conclusion, our study demonstrates that accumulation of superparamagnetic iron oxide nanoparticles does not affect kidney function in healthy mice but temporarily decreases blood pressure.

Glomeruli are histological structures of the kidney cortex formed by interwoven blood capillaries, and are responsible for blood filtration. Glomerular lesions impair kidney filtration capability, leading to protein loss and metabolic waste retention. An example of lesion is the glomerular hypercellularity, which is characterized by an increase in the number of cell nuclei in different areas of the glomeruli. Glomerular hypercellularity is a frequent lesion present in different kidney diseases. Automatic detection of glomerular hypercellularity would accelerate the screening of scanned histological slides for the lesion, enhancing clinical diagnosis. Having this in mind, we propose a new approach for classification of hypercellularity in human kidney images. Our proposed method introduces a novel architecture of a convolutional neural network (CNN) along with a support vector machine, achieving near perfect average results with the FIOCRUZ data set in a binary classification (lesion or normal). Our deep-based classifier outperformed the state-of-the-art results on the same data set. Additionally, classification of hypercellularity sub-lesions was also performed, considering mesangial, endocapilar and both lesions; in this multi-classification task, our proposed method just failed in 4\% of the cases. To the best of our knowledge, this is the first study on deep learning over a data set of glomerular hypercellularity images of human kidney.

The quantitative detection, segmentation, and characterization of glomeruli from high-resolution whole slide imaging (WSI) play essential roles in the computer-assisted diagnosis and scientific research in digital renal pathology. Historically, such comprehensive quantification requires extensive programming skills in order to be able to handle heterogeneous and customized computational tools. To bridge the gap of performing glomerular quantification for non-technical users, we develop the Glo-In-One toolkit to achieve holistic glomerular detection, segmentation, and characterization via a single line of command. Additionally, we release a large-scale collection of 30,000 unlabeled glomerular images to further facilitate the algorithmic development of self-supervised deep learning. The inputs of the Glo-In-One toolkit are WSIs, while the outputs are (1) WSI-level multi-class circle glomerular detection results (which can be directly manipulated with ImageScope), (2) glomerular image patches with segmentation masks, and (3) different lesion types. To leverage the performance of the Glo-In-One toolkit, we introduce self-supervised deep learning to glomerular quantification via large-scale web image mining. The GGS fine-grained classification model achieved a decent performance compared with baseline supervised methods while only using 10% of the annotated data. The glomerular detection achieved an average precision of 0.627 with circle representations, while the glomerular segmentation achieved a 0.955 patch-wise Dice Similarity Coefficient (DSC).

Glomerular pathology is central to the diagnosis and prognosis of renal diseases, yet the heterogeneity of glomerular morphology and fine-grained lesion patterns remain challenging for current AI approaches. We present GloPath, an entity-centric foundation model trained on over one million glomeruli extracted from 14,049 renal biopsy specimens using multi-scale and multi-view self-supervised learning. GloPath addresses two major challenges in nephropathology: glomerular lesion assessment and clinicopathological insights discovery. For lesion assessment, GloPath was benchmarked across three independent cohorts on 52 tasks, including lesion recognition, grading, few-shot classification, and cross-modality diagnosis-outperforming state-of-the-art methods in 42 tasks (80.8%). In the large-scale real-world study, it achieved an ROC-AUC of 91.51% for lesion recognition, demonstrating strong robustness in routine clinical settings. For clinicopathological insights, GloPath systematically revealed statistically significant associations between glomerular morphological parameters and clinical indicators across 224 morphology-clinical variable pairs, demonstrating its capacity to connect tissue-level pathology with patient-level outcomes. Together, these results position GloPath as a scalable and interpretable platform for glomerular lesion assessment and clinicopathological discovery, representing a step toward clinically translatable AI in renal pathology.

Background and Objective: To address the inability of single-model architectures to perform simultaneous analysis of complex glomerular ultrastructures, we developed Glo-UMF, a unified multi-model framework integrating segmentation, classification, and detection to systematically quantify key ultrastructural features. Methods: Glo-UMF decouples quantification tasks by constructing three dedicated deep models: an ultrastructure segmentation model, a glomerular filtration barrier (GFB) region classification model, and an electron-dense deposits (EDD) detection model. Their outputs are integrated through a post-processing workflow with adaptive GFB cropping and measurement location screening, enhancing measurement reliability and providing comprehensive quantitative results that overcome the limitations of traditional grading. Results: Trained on 372 electron microscopy images, Glo-UMF enables simultaneous quantification of glomerular basement membrane (GBM) thickness, the degree of foot process effacement (FPE), and EDD location. In 115 test cases spanning 9 renal pathological types, the automated quantification results showed strong agreement with pathological reports, with an average processing time of 4.23$\pm$0.48 seconds per case on a CPU environment. Conclusions: The modular design of Glo-UMF allows for flexible extensibility, supporting the joint quantification of multiple features. This framework ensures robust generalization and clinical applicability, demonstrating significant potential as an efficient auxiliary tool in glomerular pathological analysis.

Membranous nephropathy (MN) is a frequent type of adult nephrotic syndrome, which has a high clinical incidence and can cause various complications. In the biopsy microscope slide of membranous nephropathy, spikelike projections on the glomerular basement membrane is a prominent feature of the MN. However, due to the whole biopsy slide contains large number of glomeruli, and each glomerulus includes many spike lesions, the pathological feature of the spikes is not obvious. It thus is time-consuming for doctors to diagnose glomerulus one by one and is difficult for pathologists with less experience to diagnose. In this paper, we establish a visualized classification model based on the multi-scale annotation multi-instance learning (MSA-MIL) to achieve glomerular classification and spikes visualization. The MSA-MIL model mainly involves three parts. Firstly, U-Net is used to extract the region of the glomeruli to ensure that the features learned by the succeeding algorithm are focused inside the glomeruli itself. Secondly, we use MIL to train an instance-level classifier combined with MSA method to enhance the learning ability of the network by adding a location-level labeled reinforced dataset, thereby obtaining an example-level feature representation with rich semantics. Lastly, the predicted scores of each tile in the image are summarized to obtain glomerular classification and visualization of the classification results of the spikes via the usage of sliding window method. The experimental results confirm that the proposed MSA-MIL model can effectively and accurately classify normal glomeruli and spiked glomerulus and visualize the position of spikes in the glomerulus. Therefore, the proposed model can provide a good foundation for assisting the clinical doctors to diagnose the glomerular membranous nephropathy.

In the recent years we have shown that cylindrical biological membranes such as nerve axons under physiological conditions are able to support stable electromechanical pulses called solitons. These pulses share many similarities with the nervous impulse, e.g., the propagation velocity as well as the measured reversible heat production and changes in thickness and length that cannot be explained with traditional nerve models. A necessary condition for solitary pulse propagation is the simultaneous existence of nonlinearity and dispersion, i.e., the dependence of the speed of sound on density and frequency. A prerequisite for the nonlinearity is the presence of a chain melting transition close to physiological temperatures. The transition causes a density dependence of the elastic constants which can easily be determined by experiment. The frequency dependence is more difficult to determine. The typical time scale of a nerve pulse is 1 ms, corresponding to a characteristic frequency in the range up to one kHz. Dispersion in the sub-kHz regime is difficult to measure due to the very long wave lengths involved. In this contribution we address theoretically the dispersion of the speed of sound in lipid membranes and relate it to experimentally accessible relaxation times by using linear response theory. This ultimately leads to an extension of the differential equation for soliton propagation.

A method for determining permeability of phospholipid bilayer based on the osmotic swelling of micrometer-sized giant unilamellar vesicles (GUVs) is presented as an alternative to the two established techniques, dynamic light scattering on liposome suspension, and electrical measurements on planar lipid bilayers. In the described technique, an individual GUV is transferred using a micropipette from a sucrose/glucose solution into an isomolar solution containing the solute under investigation. Throughout the experiment, vesicle cross-section is monitored and recorded using a digital camera mounted on a phase-contrast microscope. Using a least-squares procedure for circle fitting, vesicle radius R is computed from the recorded images of vesicle cross-section. Two methods for determining membrane permeability from the obtained R(t) dependence are described: the first one uses the slope of R(t) for a spherical GUV, and the second one the R(t) dependence around the transition point at which a flaccid vesicle transforms into a spherical one. We demonstrate that both methods give consistent estimates for membrane permeability.

For many biotechnological applications it would be useful to better understand the effects produced by electric fields on lipid membranes. This review discusses several aspects of the electrostatic properties of a planar lipid membrane with its surrounding electrolyte in a normal DC or AC electric field. In the planar geometry, the analysis of electrokinetic equations can be carried out quite far, allowing to characterize analytically the steady state and the dynamics of the charge accumulation in the Debye layers, which results from the application of the electric field. For a conductive membrane in an applied DC electric field, we characterize the corrections to the elastic moduli, the appearance of a membrane undulation instability and the associated flows which are built up near the membrane. For a membrane in an applied AC electric field, we analytically derive the impedance from the underlying electrokinetic equations. We discuss different relevant effects due to the membrane conductivity or due to the bulk diffusion coefficients of the ions. Of particular interest is the case where the membrane has selective conductivity for only one type of ion. These results, and future extensions thereof, should be useful for the interpretation of impedance spectroscopy data used to characterize e.g. ion channels embedded in planar bilayers.

Lipid bilayer membranes are the fundamental biological barriers that permit life. The bilayer dynamics largely participates in orchestrating cellular workings and is characterized by substantial stability together with extreme plasticity that allows controlled morphological/topological changes. Modeling and understanding the topological change of vesicle-like membrane at the scale of a full cell has proved an elusive aim. We propose and discuss here a continuum model able to encompass the fusion/fission transition of a bilayer membrane at the scale of a Large Unilamellar Vesicle and evaluate the minimal free energy path across the transition, inspired by the idea that fusion/fission-inducing proteins have evolved in Nature towards minimal work expenditure. The results predict the correct height for the energetic barrier and provide the force field that, by acting on the membrane, can induce the transition. They are found in excellent agreement, in terms of intensity, scale, and spatial localization with experimental data on typical protein systems at play during the transition. The model may pave the way for the development of more complete models of the process where the dynamics is coupled to the fluid internal and external environment and to other applications where the topological changes do either occur or should be prevented.

Supported lipid membranes are useful and important model systems for studying cell membrane properties and membrane mediated processes. One attractive application of supported membranes is the design of phantom cells exhibiting well defined adhesive properties and receptor densities. Adhesion of membranes may be achieved by specific and non-specific interactions, and typically requires the clustering of many adhesion bonds into "adhesion domains". One potential mediator of the early stages of the aggregation process is the Casimir-type forces between adhesion sites induced by the membrane thermal fluctuations. In this review, I will present a theoretical analysis of fluctuation induced aggregation of adhesion sites in supported membranes. I will first discuss the influence of a single attachment point on the spectrum of membrane thermal fluctuations, from which the free energy cost of the attachment point will be deduced. I will then analyze the problem of a supported membrane with two adhesion points. Using scaling arguments and Monte Carlo simulations, I will demonstrate that two adhesion points attract each other via an infinitely long range effective potential that grows logarithmically with the pair distance. Finally, I will discuss the many-body nature of the fluctuation induced interactions. I will show that while these interactions alone are not sufficient to allow the formation of aggregation clusters, they greatly reduce the strength of the residual interactions required to facilitate cluster formation. Specifically, for adhesion molecules interacting via a short range attractive potential, the strength of the direct interactions required for aggregation is reduced by about a factor of two to below the thermal energy $k_BT$.

Atherosclerotic plaques are fatty growths in artery walls that cause heart attacks and strokes. Plaque formation is orchestrated by macrophages that are recruited to the artery wall to consume and remove blood-derived lipids, such as low-density lipoprotein (LDL). Ineffective lipid removal, due to macrophage death and other factors, leads to the accumulation of lipid-loaded macrophages and formation of a necrotic core. Experimental observations suggest that macrophage functionality varies with the extent of lipid loading. However, little is known about the resultant influence on plaque fate. Extending work by Ford et al. (2019) and Chambers et al. (2022), we develop a plaque model in which macrophages are classified by their ingested lipid content and behave in a lipid-dependent manner. The model, a system of partial-integro differential equations, considers several macrophage behaviours. These include: recruitment to the artery wall; proliferation and apoptosis; ingestion of LDL, apoptotic cells and necrotic lipid; emigration from the artery wall; and necrosis of apoptotic cells. Here, we consider apoptosis, emigration and proliferation to be lipid-dependent. We model lipid-dependence in these behaviours with experimentally-informed functions of the internalised lipid load. Our results demonstrate that lipid-dependent macrophage behaviour can substantially alter plaque fate by changing both the total quantity of lipid in the plaque and the distribution of lipid between the live cells, dead cells and necrotic core. For lipid-dependent apoptosis and lipid-dependent emigration simulations, we find significant differences in outcomes for cases that ultimately converge on the same net rate of apoptosis or emigration.

Lipid-protein interactions play essential roles in cellular signaling and membrane dynamics, yet their systematic characterization has long been hindered by the inherent biochemical properties of lipids. Recent advances in functionalized lipid probes -- equipped with photoactivatable crosslinkers, affinity handles, and photocleavable protecting groups -- have enabled proteomics-based identification of lipid interacting proteins with unprecedented specificity and resolution. Despite the growing number of published lipid interactomes, there remains no centralized effort to harmonize, compare, or integrate these datasets. The Lipid Interactome addresses this gap by providing a structured, interactive web portal that adheres to FAIR data principles -- ensuring that lipid interactome studies are Findable, Accessible, Interoperable, and Reusable. Through standardized data formatting, interactive visualizations, and direct cross-study comparisons, this resource enables researchers to systematically explore the protein-binding partners of diverse bioactive lipids. By consolidating and curating lipid interactome proteomics data from multiple studies, the Lipid Interactome database serves as a critical tool for deciphering the biological functions of lipids in cellular systems.

The outstanding lubrication of articular cartilage in the major synovial joints such as hips and knees, essential for the joint well-being, has been attributed to boundary layers of lipids at the outer cartilage surfaces, which have very low friction mediated by the hydration lubrication mechanism at their highly hydrated exposed headgroups. However, the role of spontaneously present lipid splays, lipids with an acyl tail in each of the opposing bilayers, in modulating the frictional force between lipid bilayers has not, to date, been considered. In this study, we perform all-atom molecular dynamics simulations to quantitatively assess the significance of splayed molecules within the framework of lubricating lipid bilayers. We demonstrate that, although transient, splayed molecules significantly increase the inter-membrane friction until their retraction back into the lamellar phase, with this effect more steadily occurring at lower sliding velocities that are comparable to the physiological velocities of sliding articular cartilage.

In this study, we generate and maintain a database of 10 million virtual lipids through METiS's in-house de novo lipid generation algorithms and lipid virtual screening techniques. These virtual lipids serve as a corpus for pre-training, lipid representation learning, and downstream task knowledge transfer, culminating in state-of-the-art LNP property prediction performance. We propose LipidBERT, a BERT-like model pre-trained with the Masked Language Model (MLM) and various secondary tasks. Additionally, we compare the performance of embeddings generated by LipidBERT and PhatGPT, our GPT-like lipid generation model, on downstream tasks. The proposed bilingual LipidBERT model operates in two languages: the language of ionizable lipid pre-training, using in-house dry-lab lipid structures, and the language of LNP fine-tuning, utilizing in-house LNP wet-lab data. This dual capability positions LipidBERT as a key AI-based filter for future screening tasks, including new versions of METiS de novo lipid libraries and, more importantly, candidates for in vivo testing for orgran-targeting LNPs. To the best of our knowledge, this is the first successful demonstration of the capability of a pre-trained language model on virtual lipids and its effectiveness in downstream tasks using web-lab data. This work showcases the clever utilization of METiS's in-house de novo lipid library as well as the power of dry-wet lab integration.

The vesiculation process was examined in the lipid-detergent solution (dimyristoyl-sn-glycero-phoshatidylcholine/octaethylleneglycol n-dodecyl ether/water), using small-angle neutron scattering experiments \cite{1}. When observing vesiculation proceeds from rod-like micelles to unilamellar vesicles, the transformation is induced by jump-like temperature increase and a monotonic increase in detergent concentration. Our numerical estimations of the vesicle shape parameters (the elasticity coefficients and its fraction on a macroscopic scale) are based upon the area-difference elasticity model \cite{2, 3}. Thus, we composed the numerical Monte Carlo method, which connects the macroscopic and microscopic scales by the concept of self-avoiding random surfaces.

The cross section for prompt neutral and charged three pion production in pp interactions was measured at excess energies in the range 160 - 217 MeV. That comprises the first measurement of the pp->pp pi0pi0pi0 reaction and the comparison with the pp->pp pi+pi-pi0 reaction, in a very direct way. The experiment was performed above the eta meson production threshold and the cross section normalization was obtained from a concurrent measurement of the reaction pp->pp eta with the eta decaying into 3 pions. Since the same final states are selected, the measurement has a low systematical error. The measured cross section ratio sigma(pp->pp pi+pi-pi0)/sigma(pp->pp pi0\pi0\pi0) is compared to predictions of dominance of different isobars in the intermediate state.

Minimax and maximin problems are investigated for a special class of functions on the interval $[0,1]$. These functions are sums of translates of positive multiples of one kernel function and a very general external field function. Due to our very general setting the obtained minimax, equioscillation, and characterization results extend those of Bojanov, Fenton, Hardin, Kendall, Saff and Ambrus, Ball, Erdélyi. Moreover, we discover a surprising intertwining phenomenon of interval maxima, which provides new information even in the most classical extremal problem of Chebyshev.

Reaction networks are a general framework widely used in modeling diverse phenomena in different science disciplines. The dynamical process of a reaction network endowed with mass-action kinetics is a mass-action system as an ODE defined by a directed graph, the so-called ``reaction graph''. Endotacticity is a graph property used to study persistence and permanence of mass-action systems. In this paper, we provide a detailed characterization of first order endotactic reaction graphs. Besides, we provide a sufficient condition for endotacticity of reaction networks which are not necessarily of first order. Such a characterization of a first order endotactic reaction graph yields the spectral property of the adjacency matrix of the reaction graph. As a consequence, we prove that every first order endotactic mass-action system as a linear ODE has a weakly reversible deficiency zero realization, and has a unique equilibrium which is exponentially globally asymptotically stable (and is positive) in each (positive) stoichiometric compatibility class. Using a stability result for asymptotically autonomous differential equations, examples are constructed to illustrate that the global stability results can be extended to mass-action systems of higher order reaction networks modeled by nonlinear ODEs, which are not necessarily endotactic. Different from the classical approaches for proving global asymptotic stability, the proof does not rely on the construction of a Lyapunov function. This paper may serve as a starting point of characterizing endotactic reaction graphs of higher orders and studying global stability of mass-action systems in general.

We provide a Jacobian criterion that applies to arbitrary chemical reaction networks taken with mass-action kinetics to preclude the existence of multiple positive steady states within any stoichiometric class for any choice of rate constants. We are concerned with the characterization of injective networks, that is, networks for which the species formation rate function is injective in the interior of the positive orthant within each stoichiometric class. We show that a network is injective if and only if the determinant of the Jacobian of a certain function does not vanish. The function consists of components of the species formation rate function and a maximal set of independent conservation laws. The determinant of the function is a polynomial in the species concentrations and the rate constants (linear in the latter) and its coefficients are fully determined. The criterion also precludes the existence of degenerate steady states. Further, we relate injectivity of a chemical reaction network to that of the chemical reaction network obtained by adding outflow, or degradation, reactions for all species.

The past few decades have seen robust research on questions regarding the existence, form, and properties of stationary distributions of stochastically modeled reaction networks. When a stochastic model admits a stationary distribution an important practical question is: what is the rate of convergence of the distribution of the process to the stationary distribution? With the exception of \cite{XuHansenWiuf2022} pertaining to models whose state space is restricted to the non-negative integers, there has been a notable lack of results related to this rate of convergence in the reaction network literature. This paper begins the process of filling that hole in our understanding. In this paper, we characterize this rate of convergence, via the mixing times of the processes, for two classes of stochastically modeled reaction networks. Specifically, by applying a Foster-Lyapunov criteria we establish exponential ergodicity for two classes of reaction networks introduced in \cite{anderson2018some}. Moreover, we show that for one of the classes the convergence is uniform over the initial state.

The covalent functionalization of single-walled carbon nanotubes (SWNTs) with luminescent oxygen defects increases their brightness and enables their application as optical biosensors or fluorescent probes for in-vivo imaging in the second-biological window (NIR-II). However, obtaining luminescent defects with high brightness is challenging with the current functionalization methods due to a restricted window of reaction conditions or the necessity for controlled irradiation with ultraviolet light. Here we report a method for introducing luminescent oxygen defects via a Fenton-like reaction that uses benign and inexpensive chemicals without light irradiation. (6,5) SWNTs in aqueous dispersion functionalized with this method show bright $E_{11}$* emission (1105 nm) with 3.2-times higher peak intensities than the pristine $E_{11}$ emission and a reproducible photoluminescence quantum yield of 3%. The functionalization can be performed within a wide range of reaction parameters and even with unsorted nanotube raw material at high concentrations (100 mg/L), giving access to large amounts of brightly luminescent SWNTs. We further find that the introduced oxygen defects rearrange under light irradiation, which gives additional insights into the structure and dynamics of oxygen defects. Finally, the functionalization of ultra-short SWNTs with oxygen defects also enables high photoluminescence quantum yields and their excellent emission properties are retained after surfactant exchange with biocompatible pegylated phospholipids or single-stranded DNA to make them suitable for in-vivo NIR-II imaging and dopamine sensing.

We mathematically prove that chemical reaction networks without hidden layers can solve tasks for which spiking neural networks require hidden layers. Our proof uses the deterministic mass-action kinetics formulation of chemical reaction networks. Specifically, we prove that a certain reaction network without hidden layers can learn a classification task previously proved to be achievable by a spiking neural network with hidden layers. We provide analytical regret bounds for the global behavior of the network and analyze its asymptotic behavior and Vapnik-Chervonenkis dimension. In a numerical experiment, we confirm the learning capacity of the proposed chemical reaction network for classifying handwritten digits in pixel images, and we show that it solves the task more accurately and efficiently than a spiking neural network with hidden layers. This provides a motivation for machine learning in chemical computers and a mathematical explanation for how biological cells might exhibit more efficient learning behavior within biochemical reaction networks than neuronal networks.

The internal structure of self-interacting quantum particle like electron is independent on space-time position. Then at least infinitesimal kinematic space-time shift, rotation or boost lead to the equivalent internal quantum state. This assumption may be treated as internal (quantum) formulation of the inertia principle. Dynamical transformation of quantum setup generally leads to deformation of internal quantum state and measure of this deformation may be used as quantum counterpart of force instead of a macroscopic acceleration. The reason of inertia arises, thereby, as a consequence an internal motion of quantum state and its reaction on dynamical quantum setup deformation. The quantum origin of the inertia has been discussed in this article in the framework of "eigen-dynamics" of self-interacting relativistic extended quantum electron. Namely, a back reaction of spin and charge "fast" degrees of freedom on "slow" driving environment during "virtual measurement" leads to the appearance of state dependent non-Abelian gauge fields in dynamical 4D space-time. Analysis of simplified dynamics has been applied to the energy-momentum behavior in the relation with runaway solutions of previous models of an electron.

In this study, the comparative efficiency of different electrochemical advanced oxidation processes, such as anodic oxidation with electrogenerated H2O2 (AO- H2O2), electro-Fenton (EF), and its combination with UV irradiation (photoelectron-Fenton (PEF)), was investigated for the removal of methylparaben (MP) using a carbon felt cathode and a boron-doped diamond anode. The EF process achieved a higher MP removal efficiency than the AO-H2O2 process for all applied current densities. The total organic carbon (TOC) removal after 6 h of treatment at a current density of 10 mA cm-2 reached 75.0% and 91.9% for the AO- H2O2 and EF processes, respectively. The combination of EF and UV light improved the efficiency of the EF process. The PEF process achieved a TOC removal of 84.6% in only 2 h at 5 mA cm-2 and 96.8% after 6 h of treatment. Furthermore, based on identifying oxidation reaction intermediates and short-chain carboxylic acids generated during the treatment, a reaction pathway for methylparaben mineralization by hydroxyl radicals was proposed.

We study statistical aspects of the case of the British nurse Ben Geen, convicted of 2 counts of murder and 15 of grievous bodily harm following events at Horton General Hospital (in the town of Banbury, Oxfordshire, UK) during December 2013-February 2014. We draw attention to parallels with the cases of nurses Lucia de Berk (the Netherlands) and Daniela Poggiali (Italy), in both of which an initial conviction for multiple murders of patients was overturned after reopening of the case. We pay most attention to the investigative processes by which data, and not just statistical data, is generated; namely, the identification of past cases in which the nurse under suspicion might have been involved. We argue that the investigation and prosecution of such cases is vulnerable to many cognitive biases and errors of reasoning about uncertainty, complicated by the fact that fact-finders have to determine not only whether a particular person was guilty of certain crimes, but whether any crimes were committed by anybody at all. The paper includes some new statistical findings on the Ben Geen case and suggests further avenues for investigation. The experiences recounted here have contributed to the writing of the hand-book Green et al. (2022), Healthcare Serial Killer or Coincidence? Statistical Issues in Investigation of Suspected Medical Misconduct, commissioned by the Royal Statistical Society, Statistics and the Law section. Submitted to MDPI Laws. This version: 5 August, 2022.

Diabetic nephropathy (DN) is a severe complication of diabetes mellitus, causing a substantive threat to the public, which receives global concern. However, there are limited drugs targeting the treatment of DN. Owing to this, it is highly crucial to investigate the pathogenesis and potential therapeutic targets of DN. The process of ferroptosis is a type of regulated cell death (RCD) involving the presence of iron, distinct from autophagy, apoptosis, and pyroptosis. A primary mechanism of ferroptosis is associated with iron metabolism, lipid metabolism, and the accumulation of ROS. Recently, many studies testified to the significance of ferroptosis in kidney tissue under diabetic conditions and explored the drugs targeting ferroptosis in DN therapy. Our review summarized the most current studies between ferroptosis and DN, along with investigating the significant processes of ferroptosis in different kidney cells, providing a novel target treatment option for DN.

It is widely acknowledged that cisplatin-induced nephrotoxicity hinders its efficacy during clinical therapy. Effective pharmaceutical interventions for cisplatin-induced acute kidney injury (Cis-AKI) are currently lacking. Prior studies have implicated the chemokine CX3CL1 in the development of lipopolysaccharide-induced AKI; however, its specific role in Cis-AKI remains uncertain. This research aimed to comprehensively characterize the therapeutic impact and mechanism of CX3CL1 inhibition on Cis-AKI. This study employed an in vivo Cis-AKI mouse model and in vitro cisplatin-treated podocytes. Kidney pathological changes were assessed using hematoxylin-eosin (HE) and Periodic-Schiff (PAS) staining. Transcriptome changes in mouse kidney tissue post-cisplatin treatment were analyzed through RNA sequencing (RNA-seq) datasets. Evaluation parameters included the expression of inflammatory markers, intracellular free iron levels, ferroptosis-related proteins-solute carrier family 7 member 11 (SLC7A11/XCT) and glutathione peroxidase 4 (GPX4)-as well as lipid peroxidation markers and mitochondrial function proteins. Mitochondrial morphological changes were visualized through transmission electron microscopy. The impact of CX3CL1 on the glucose-regulated protein 78/eukaryotic translation initiation factor 2A/CCAAT enhancer binding protein-homologous protein (GRP78/eIF2α/CHOP) and hypoxia-inducible factor 1-alpha/heme oxygenase-1 (HIF1A/HO-1) pathways in Cis-AKI was assessed via Western Blot and Immunofluorescence experiments, both in vivo and in vitro. Kidney CX3CL1 levels were elevated following cisplatin injection in wild-type (WT) mice. Cisplatin-treated CX3CL1-Knockout mice exhibited reduced renal histological changes, lowered blood creatinine (Cre) and blood urea nitrogen (BUN) levels, and decreased expression of inflammatory mediators compared to cisplatin-treated WT mice. RNA-seq analysis revealed the modulation of markers associated with oxidative stress and lipid metabolism related to ferroptosis in the kidneys of mice with Cis-AKI. Both the in vivo Cis-AKI mouse model and in vitro cisplatin-treated podocytes demonstrated that CX3CL1 inhibition could mitigate ferroptosis. This effect was characterized by alleviated intracellular iron overload, malondialdehyde (MDA) content, and reactive oxygen species (ROS) production, alongside increased glutathione/glutathione disulfide ratio, superoxide dismutase (SOD), XCT, and GPX4 activity. CX3CL1 inhibition also ameliorated mitochondrial dysfunction and upregulated expression of mitochondrial biogenesis proteins-uncoupling protein (UCP), mitofusin 2 (Mfn2), and peroxisome proliferators-activated receptor γ coactivator l-alpha (PGC1α)-both in vivo and in vitro. Furthermore, CX3CL1 inhibition attenuated cisplatin-induced endoplasmic reticulum (ER) stress in podocytes. Notably, CX3CL1 inhibition reduced cisplatin-induced expression of HIF-1α and HO-1 in vivo and in vitro. Our findings suggest that CX3CL1 inhibition exerts therapeutic effects against Cis-AKI by suppressing podocyte ferroptosis.

Hepatitis B virus-associated glomerulonephritis (HBV-GN) is a common secondary kidney disease in China, the pathogenesis of which is not completely clear, and there is still a lack of effective treatment. The mechanism of exosomes derived from bone marrow mesenchymal stem cells (BMSCs) was investigated by using HBx-transfected human renal podocytes. Cell viability was detected by CCK8 assay. Iron and malondialdehyde (MDA) contents were detected by using commercial kits. Reactive oxygen species (ROS) levels were measured by flow cytometry analysis. The expression of ferroptosis related molecules was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. The effect of miR-223-3p transferred by BMSC-derived exosomes on HBx-overexpressing podocytes was proved by using miR-223-3p inhibitor. The cell viability of podocytes reduced at 72 h or 96 h after the transfection of lentivirus overexpressing HBx protein ( BMSC-derived exosomes inhibit HBx-induced podocyte ferroptosis by transferring miR-223-3p.

To explore the mechanism of acupuncture to relieve diabetic proteinuria in Diabetic Kidney Disease (DKD). A total of 10 male Sprague-Dawley rats were randomly selected as the negative control group (NC), and a further 30 rats were fed a high-fat diet (HFD) and intraperitoneal streptozotocin (STZ). The DKD model rats in the model group (DKD) and the acupuncture group (DKD + Acu) were randomly assigned. After 4 weeks of intervention, collected urine, peripheral blood, and renal tissues from all rats, and assessed blood urea nitrogen, serum creatinine, triglyceride, 24-h urine protein quantification, and blood glucose, left kidney weight, kidney body ratio index, then observe changes in renal histology in the rats. The renal cortex tissues of three rats from each group were sent for transcriptomic analysis. According to the results of transcriptomic analysis, various kits were used to detect SOD, MDA, GSH, GSH-px, and iron concentration. The expression levels of GPX4 and System Xc-, members of the antioxidative stress pathway, and TfR 1, SLC39A14, FTH 1, and SLC40A1, involved in iron metabolism, in the kidney tissues were measured by western blotting and reverse transcription-quantitative PCR. The expression of mesenchymal phenotype markers and podocyte-specific markers were evaluated by immunofluorescence. Acupuncture promoted the levels of GSH, GSH-px, and SOD, decreased the level of MDA (P < 0.05), promoted the expression of GPX4 and System Xc- ( Improving the ability of podocytes to prevent oxidative stress and restoring iron ion homeostasis, can improve Ferroptosis and block epithelial-mesenchymal transition, improve podocyte injury, restore filtration function, and reduce proteinuria in DKD rats.

Homozygosity for the hemoglobin (Hb) S mutation (HbSS, sickle cell anemia) results in hemoglobin polymerization under hypoxic conditions leading to vaso-occlusion and hemolysis. Sickle cell anemia affects 1:500 African Americans and is a strong risk factor for kidney disease, although the mechanisms are not well understood. Heterozygous inheritance (HbAS; sickle cell trait) affects 1:10 African Americans and is associated with an increased risk for kidney disease in some reports. Using transgenic sickle mice, we investigated the histopathologic, ultrastructural, and gene expression differences with the HbS mutation. Consistent with progressive glomerular damage, we observed progressively greater urine protein concentrations (P = 0.03), glomerular hypertrophy (P = 0.002), and glomerular cellularity (P = 0.01) in HbAA, HbAS, and HbSS mice, respectively. Ultrastructural studies demonstrated progressive podocyte foot process effacement, glomerular basement membrane thickening with reduplication, and tubular villous atrophy with the HbS mutation. Gene expression studies highlighted the differential expression of several genes involved in prostaglandin metabolism (AKR1C18), heme and iron metabolism (HbA-A2, HMOX1, SCL25A37), electrolyte balance (SLC4A1, AQP6), immunity (RSAD2, C3, UBE2O), fatty acid metabolism (FASN), hypoxia hall-mark genes (GCK, SDC3, VEGFA, ETS1, CP, BCL2), as well as genes implicated in other forms of kidney disease (PODXL, ELMO1, FRMD3, MYH9, APOA1). Pathway analysis highlighted increased gene enrichment in focal adhesion, extracellular matrix-receptor interaction, and axon guidance pathways. In summary, using transgenic sickle mice, we observed that inheritance of the HbS mutation is associated with glomerular and tubular damage and identified several candidate genes and pathways for future investigation in sickle cell trait and sickle cell anemia-related kidney disease.

Although Heme Oxygenase-1 (HO-1) induction in various forms of kidney injury is protective, its role in age-related renal pathology is unknown. In the ageing kidney there is nephron loss and lesions of focal glomerulosclerosis, interstitial fibrosis, tubular atrophy and arteriolosclerosis. Underlying mechanisms include podocyte (visceral glomerular epithelial cell/GEC) injury. To assess whether HO-1 can attenuate ageing - related lesions, rats with GEC-targeted HO-1 overexpression (GEC

Ferroptosis is a regulated form of cell death driven by iron-dependent lipid peroxidation. Emerging evidence implicates ferroptosis in the pathogenesis of various kidney diseases by inducing death in renal tubular epithelial cells (RTECs), podocytes, mesangial cells (MCs), and endothelial cells (ECs), which exhibit distinct structural and functional traits that might determine their differential susceptibility to ferroptosis. Despite its importance, the precise mechanism of ferroptosis in kidney pathology remains unclear, limiting its therapeutic potential and drug development. Understanding cell type-specific ferroptosis mechanisms and their spatial distribution in kidney diseases could provide novel insights for renal protection. In this review, we summarize current knowledge regarding ferroptosis susceptibility in different renal cell types to bridge cellular and organ-level perspectives for potential translational applications.

Iron is associated with the pathogenesis of chronic kidney disease (CKD). Activation of mineralocorticoid receptor signaling is implicated in CKD; however, a link between iron and mineralocorticoid receptor signaling in CKD remains unknown. We have previously shown that long-term dietary iron restriction leads to increased sodium and decreased potassium excretions in the rat urine. Herein, we investigated the effect of iron restriction on renal damage and mineralocorticoid receptor signaling in a rat model of CKD. CKD was induced by 5/6 nephrectomy in Sprague-Dawley rats. CKD rats were divided into untreated and dietary iron-restricted groups. CKD rats exhibited proteinuria, glomerulosclerosis, tubulointerstitinal damage, and podocyte injury. In contrast, these changes were attenuated by 16 weeks of iron-restricted diet. Consistent with these findings, iron restriction suppressed increased gene expression of collagen type III, transforming growth factor-β, CD68, and tumor necrosis factor-α in the CKD kidney. Importantly, increased expression of nuclear mineralocorticoid receptor and SGK1, a key downstream effector of mineralocorticoid receptor signaling, in the CKD kidney was markedly attenuated by iron restriction. Of interest, expression of cellular iron transport proteins, transferrin receptor 1, and divalent metal transporter 1 was increased in the CKD renal tubules, along with increased iron accumulation, superoxide production, and urinary iron excretion. CKD rats also developed hypertension, although iron restriction suppressed the development of hypertension. Taken together, these data uncover a novel effect of iron restriction on renal damage and hypertension through the inhibition of renal mineralocorticoid receptor signaling.

This study traced intravenously administered induced pluripotent stem cell (iPSC)-derived mesenchymal stem cells (MSC) and assessed the impact of iPSC-MSC on preserving renal function in SD rat after 5/6 nephrectomy. The results of in vitro study showed that FeraTrack™Direct contrast particles (ie intracellular magnetic labelling) in the iPSC-MSC (ie iPS-MSC

In the present study in Munich-Wistar rats during the initial stages of autologous immune complex nephritis (protein excretion 3 to 50 mg/24 hours) we examined the sequential changes in binding of cationized ferritin to anionic sites, as well as alterations in staining with colloidal iron of podocyte membrane sialoglycoprotein and correlated these with changes in glomerular basement membrane permeability to native ferritin. The results are compared with those obtained from rats with advanced autologous immune complex nephritis (protein excretion 100 to 350 mg/24 hours) and with normal control rats. The formation of the smallest detectable immune complex deposits was associated with a concomitant decrease in binding of cationized ferritin to anionic sites in the lamina rara externa in the area of the deposits. This was accompanied by a diminution in staining by colloidal iron of the epithelial cell coat overlying the deposits. The staining of the remainder of the epithelial cell glycocalyx, however, remained unaltered even in the presence of severe proteinuria. Alterations in the permeability of the glomerular basement membrane to native ferritin could not be documented until protein excretion exceeded 10 mg/24 hours. The gradual loss of staining of the epithelial cell glycocalyx adjacent to immune complexes supports the concept that, as immune complexes are formed in situ by the interaction of antibodies with a glycoprotein present on the epithelial cell surface, they are shed and gradually accumulate in the lamina rara externa. Furthermore, as the immune complex deposits enlarge they destroy and/or mask the heparan sulfate anionic sites in the lamina rara externa resulting in a decreased number of anionic binding sites for cationized ferritin.

Renal biopsies from 23 patients with the nephrotic syndrome and five patients with slight or no proteinuria were examined for the presence of cell coat of podocytes by light and electron microscopy. Of those with nephrotic syndrome, five had minimal change disease, nine focal glomerular sclerosis, six membraneous nephropathy and three amyloidosis. Colloidal iron and phosphotungstic acid stains were used for the demonstration of anionic and neutral polysaccharide components of the cell coat. On light microscopy, the colloidal iron reaction showed a reduction in intensity of the stain in glomeruli of patients with massive proteinuria, as compared to those with slight or no proteinuria. On electron microscopy, only the cell coat lining the surface of the foot processes disappeared parallel to the loss of these structures, while the coat covering the surface facing the urinary space remained unchanged with both stains.

Cordycepin (CRD) has been identified to alleviate diabetes-induced injuries and complications including diabetic nephropathy (DN). Here, this work focused on probing the specific effects and potential mechanisms of CRD on DN progression. High glucose (HG)-induced mouse podocyte cell line (MPC5) was used for in vitro functional analyses. Cell proliferation and apoptosis were determined using cell counting kit-8 assay, 5-ethynyl-2'-deoxyuridine assay, and flow cytometry, respectively. ELISA analysis detected inflammatory factors. Cell ferroptosis was assessed by measuring the levels of Fe2+, glutathione, reactive oxygen species, and malonaldehyde. CRD treatment suppressed HG-induced apoptosis, inflammation, and ferroptosis in podocytes. CRD treatment elevated SLC7A11 and GPX4 expression in HG-treated podocytes. The overexpression of SLC7A11 or GPX4 suppressed HG-evoked apoptosis, inflammation, and ferroptosis in podocytes. Moreover, the silencing of SLC7A11 or GPX4 abolished the protective effects of CRD on HG-treated podocytes. Moreover, CRD ameliorated renal structure injury and inflammation in STZ-induced diabetic mice by modulating SLC7A11 or GPX4 expression. Cordycepin suppressed HG-induced apoptosis, inflammation, and ferroptosis in podocytes in vitro, and ameliorated renal injury and inflammation in STZ-induced diabetic mice by activating the SLC7A11/GPX4 pathway.

Obesity and hyperlipidemia are the most prevalent independent risk factors of chronic kidney disease (CKD), suggesting that lipid accumulation in the renal parenchyma is detrimental to renal function. Non-esterified fatty acids (also known as free fatty acids, FFA) are especially harmful to the kidneys. A concerted, increased FFA uptake due to high fat diets, overexpression of fatty acid uptake systems such as the CD36 scavenger receptor and the fatty acid transport proteins, and a reduced β-oxidation rate underlie the intracellular lipid accumulation in non-adipose tissues. FFAs in excess can damage podocytes, proximal tubular epithelial cells and the tubulointerstitial tissue through various mechanisms, in particular by boosting the production of reactive oxygen species (ROS) and lipid peroxidation, promoting mitochondrial damage and tissue inflammation, which result in glomerular and tubular lesions. Not all lipids are bad for the kidneys: polyunsaturated fatty acids (PUFA) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) seem to help lag the progression of chronic kidney disease (CKD). Lifestyle interventions, especially dietary adjustments, and lipid-lowering drugs can contribute to improve the clinical outcome of patients with CKD.

Chronic kidney disease (CKD) is characterized by persistent renal impairment or dysfunction that lasts for at least 3 months, and typically has a progressive and irreversible trajectory. The increasing prevalence of metabolic disorders, such as hyperuricemia, dyslipidemia, obesity, and type 2 diabetes mellitus, have contributed to the increasing incidence of CKD, and it is now a significant public health concern worldwide. Accumulating evidence underscores the intricate relationships of the different metabolic disorders and how they promote the initiation and progression of CKD, and ultimately lead to end-stage renal disease (ESRD). Metabolic abnormalities promote CKD progression by various mechanisms, including oxidative stress, chronic inflammation, dysregulation of autophagy, glomerular hyperfiltration and disruption of hemodynamics, endothelial dysfunction, and dysbiosis of gut microbiota. Ectopic lipid deposition and lipid peroxidation-induced redox imbalance lead to mitochondrial dysfunction, excessive production of reactive oxygen species (ROS), and activation of the p38 MAPK, ERK, and JNK signaling pathways. Metabolic dysregulation activates NF-κB signaling pathways and NLRP3 inflammasomes, leading to increased production of pro-inflammatory factors, lysosomal dysfunction, and impaired autophagic clearance, followed by accumulation of metabolic waste and podocyte injury. Obesity and hyperlipidemia can cause excessive activation of the renin-angiotensin-aldosterone system (RAAS), which then causes glomerular hyperfiltration, endothelial and mesangial cell injury and proliferation, and ultimately glomerulosclerosis. Multiple interventions that target these mechanisms have shown therapeutic potential, and these include pharmacological treatments (xanthine oxidase inhibitors to reduce uric acid levels, statins for lipid regulation, and SGLT2 inhibitors and GLP-1 receptor agonists to improve renal and cardiovascular outcomes), lifestyle interventions (low-salt and low-protein diets, weight management, smoking cessation, and alcohol limitation), intermittent fasting, and microbiome-targeted therapies. This review analyzes the pathways by which metabolic abnormalities affect the onset and progression of CKD, identifies strategies that have potential use for prevention or treatment, and offers a robust theoretical foundation for the future development of effective clinical interventions.

The goal of this review is to review the role that renal parenchymal lipid accumulation plays in contributing to diabetic kidney disease (DKD), specifically contributing to the mitochondrial dysfunction observed in glomerular renal cells in the context of DKD development and progression. Mitochondrial dysfunction has been observed in experimental and clinical DKD. Recently, Ayanga et al. demonstrate that podocyte-specific deletion of a protein involved in mitochondrial dynamics protects from DKD progression. Furthermore, our group has recently shown that ATP-binding cassette A1 (a protein involved in cholesterol and phospholipid efflux) is significantly reduced in clinical and experimental DKD and that genetic or pharmacological induction of ABCA1 is sufficient to protect from DKD. ABCA1 deficiency in podocytes leads to mitochondrial dysfunction observed with alterations of mitochondrial lipids, in particular, cardiolipin (a mitochondrial-specific phospholipid). However, through pharmacological reduction of cardiolipin peroxidation DKD progression is reverted. Lipid metabolism is significantly altered in the diabetic kidney and renders cellular components, such as the podocyte, susceptible to injury leading to worsened DKD progression. Dysfunction of the lipid metabolism pathway can also lead to mitochondrial dysfunction and mitochondrial lipid alteration. Future research aimed at targeting mitochondrial lipids content and function could prove to be beneficial for the treatment of DKD.

The pathophysiology of diabetic nephropathy (DN) is too complex and involves a variety of pathways and mediators. Hyperglycaemia and dyslipidemia are identified as major risk factors for diabetic nephropathy. Various studies revealed the fact that dyslipidemia is a major contributor to the process of diabetic nephropathy. Dyslipidemia refers to abnormal lipid levels. Lipids like LDL, free fatty acids, abnormal lipoproteins, ceramides, etc., are unsafe for kidneys. They target proximal tubular epithelial cells, podocytes, and tubulointerstitial tissues through biochemical changes, especially by enhancing the release of reactive oxygen species (ROS) and lipid peroxidation, endorsing tissue inflammation and mitochondrial damage, which give rise to nephropathy. Major lipid targets identified are SREBP1, LXR, FXR PPAR, CD-36, PKc, AGE/RAGE pathway, and ferroptosis. The drug acting on these targets has shown improvement in DN patients. Various preclinical and clinical studies support the fact that hyperlipidemic agents are promising targets for DN. Therefore, in conjunction with other standard therapies, drugs acting on dyslipidemia can be added as a part of the regimen in order to prevent the incidence of ESRD and CVD.

Reactive oxygen species (ROS), which excessively arise in diabetes and systemic inflammatory diseases, modify cellular lipids and cellular lipid composition leading to altered biophysical properties of cellular membranes. The impact of lipid peroxidation on transmembrane signaling routes is not yet well studied. The canonical transient receptor potential channel 6 (TRPC6) is implicated in the pathogenesis of several forms of glomerular diseases. TRPC6 is sensitive to membrane stretch and relies on a distinct lipid environment. This study investigates the effect of oxidative alterations to plasma membrane lipids on TRPC6 activity and the function of the glomerular filter. Knockout of the anti-oxidative, lipid modifying enzyme paraoxonase 2 (PON2) leads to altered biophysical properties of glomerular epithelial cells, which are called podocytes. Cortical stiffness, quantified by atomic force microscopy, was largely increased in PON2-deficient cultured podocytes. PON2 deficiency markedly enhanced TRPC6 channel currents and channel recovery. Treatment with the amphiphilic substance capsazepine in micromolar doses reduced cortical stiffness and abrogated TRPC6 conductance. In in vivo studies, capsazepine reduced the glomerular phenotype in the model of adriamycin-induced nephropathy in PON2 knockout mice and wildtype littermates. In diabetic AKITA mice, the progression of albuminuria and diabetic kidney disease was delayed. In summary, we provide evidence that the modification of membrane characteristics affects TRPC6 signaling. These results could spur future research to investigate modification of the direct lipid environment of TRPC6 as a future therapeutic strategy in glomerular disease.

Oxidized lipids initiate and modulate the inflammatory cellular events in the arterial wall and the formation of macrophage foam cells. CD36 mediates the cellular uptake of ox-LDL through its recognition of specific truncated fatty acid moieties and oxidized phosphatidylcholine. Evidence has been reported that chemokine CXCL16, rather than CD36, is the main scavenger receptor in human podocytes mediating the uptake of ox-LDL. Ox-LDL induces loss of nephrin expression from cultured podocytes. It has been recently shown that nephrin once phosphorilated associates with PI3K and stimulates the Akt dependent signaling. This pathway plays a critical role in nephrin-actin-dependent cytoskeleton activation and remodeling, in the control of protein trafficking and in podocyte survival. An enhanced FFA uptake by podocytes is mediated by increased C36 scavenger receptor expression, together with a decrease of betaoxidation and in turn intracellular lipid accumulation. Accumulated FFA that is trapped into the mitochondrial matrix leads to mitochondrial ROS production, lipid peroxidation and mitochondrial damage and dysfunction. A disturbed transport and oxidation of FFA, paralleled by an impaired antioxidant response, damages podocyte structure and leads to glomerulopathy in early stages of nephrosis. Increased triglyceride synthesis and ox-and glycated LDL uptake by mesangial cells may also contribute to determine diabetic glomerulopathy. Oxidative processes are pivotal events in injury to renal tubular and epithelial cells exposed to ox-LDL. Notably CXCL16 are the main receptors for the uptake of ox-LDL in podocytes, whereas CD36 plays this role in tubular renal cells. In overt type 2 diabetes Ox-LDL and FFA damage podocyte function, SD-podocyte structure and tubulointerstitial tissue, at least partially, through different pathogenetic mechanisms. Further studies are needed to investigate the role of Ox-LDL and FFA on renal complications in obese, insulin resistant patients before the development of diabetes. The aim of the present review is to briefly elucidate the patterns of systemic lipid metabolism and the individual effects of lipotoxicity at glomerular and tubular level in the kidney of overt type 2 diabetic patients. These findings better elucidate our knowledge of diabetic glomerulopathy, beside and along with previous findings, in vivo and in vitro, on ox-LDL and FFA effects in mesangial cells.

Fibroblasts from patients with Tangier disease carrying ATP-binding cassette A1 (ABCA1) loss-of-function mutations are characterized by cardiolipin accumulation, a mitochondrial-specific phospholipid. Suppression of ABCA1 expression occurs in glomeruli from patients with diabetic kidney disease (DKD) and in human podocytes exposed to DKD sera collected prior to the development of DKD. We demonstrated that siRNA ABCA1 knockdown in podocytes led to reduced oxygen consumption capabilities associated with alterations in the oxidative phosphorylation (OXPHOS) complexes and with cardiolipin accumulation. Podocyte-specific deletion of Abca1 (Abca1fl/fl) rendered mice susceptible to DKD, and pharmacological induction of ABCA1 improved established DKD. This was not mediated by free cholesterol, as genetic deletion of sterol-o-acyltransferase-1 (SOAT1) in Abca1fl/fl mice was sufficient to cause free cholesterol accumulation but did not cause glomerular injury. Instead, cardiolipin mediates ABCA1-dependent susceptibility to podocyte injury, as inhibition of cardiolipin peroxidation with elamipretide improved DKD in vivo and prevented ABCA1-dependent podocyte injury in vitro and in vivo. Collectively, we describe a pathway definitively linking ABCA1 deficiency to cardiolipin-driven mitochondrial dysfunction. We demonstrated that this pathway is relevant to DKD and that ABCA1 inducers or inhibitors of cardiolipin peroxidation may each represent therapeutic strategies for the treatment of established DKD.

Mitochondrial injury-triggered podocyte apoptosis is a major risk factor for diabetic nephropathy (DN). However, the detailed relationship between mitochondrial homeostasis and podocyte apoptosis remains unclear. The present study aimed to explore the role and functional mechanism of germacrone in DN in type I diabetes (type I DN). A mouse model of type I DN was established by injecting streptozocin, and a podocyte injury model was constructed using high glucose (HG) induction. Histopathology was detected by hematoxylin and eosin and periodic acid-Schiff staining. Transmission electron microscopy and flow cytometry were used to evaluate the mitochondrial function. Germacrone simultaneously reduced blood glucose, 24 h proteinuria, and other nephrotic symptoms in a type 1 DN mouse model. Moreover, germacrone protected against mitochondrial damage, limited reactive oxygen species (ROS) accumulation, and restored glutathione peroxidase (GPX) activity and GPX4 protein expression, subsequently preventing podocyte apoptosis. Mechanistically, the increased miR-188-3p expression in type I DN mice was reversed in germacrone-challenged DN mice. HG induced miR-188-3p expression and the miR-188-3p antagonist abolished the HG-mediated increase in ROS. Notably, miR-188-3p was found to have a therapeutic effect against DN by aggravating mitochondrial damage and podocyte apoptosis. Germacrone alleviates DN progression in type I diabetes by limiting podocyte apoptosis, which was partly counteracted by miR-188-3p upregulation. The combination of germacrone and miR-188-3p antagonists is expected to be an effective therapeutic strategy for DN.

Cytokine-induced apoptosis inhibitor 1 (CIAPIN1) is a crucial anti-apoptotic protein; however, its role and associated molecular pathways in ferroptosis remain largely unexplored. This study aimed to investigate the effects of CIAPIN1 on ferroptosis in lipopolysaccharide (LPS)-induced podocytes and the associated underlying phenomenon. In this study, we recruited 50 sepsis patients (aged 56.63 ± 10.33) with acute kidney injury (AKI), 50 sepsis patients without AKI, and 50 healthy controls. We established an in vitro model of LPS-induced MPC5 podocytes. RT-qPCR and Western blotting were used to evaluate mRNA and protein expression, respectively. Serum CIAPIN1 is downregulated in patients with septic AKI and LPS-induced podocytes. CIAPIN1 overexpression (OE-CIAPIN1) attenuated cell proliferation and apoptosis in LPS-induced podocytes. OE-CIAPIN1 elevated phosphorylated phosphoinositide 3-kinase (p-PI3K; p85, Tyr458) and phosphorylated protein kinase B (p-Akt; Ser473) levels in LPS-induced podocytes. OE-CIAPIN1 significantly elevated synaptopodin mRNA levels and remarkably lowered desmin mRNA expression in MPC5 cells. In contrast, treatment with the PI3K/Akt pathway inhibitor, LY294002, reversed synaptopodin and desmin mRNA expression in MPC5 cells. Additionally, OE-CIAPIN1 reduced the malondialdehyde (MDA) content and Fe2 + concentration in the lysate of MPC5 cells, while elevating the MDA content and Fe2 + concentration by LY294002 treatment. Furthermore, OE-CIAPIN1 increased ferroptosis-related proteins, including solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4), in MPC5 cells, which was reversed by LY294002 treatment. These results suggest that serum CIAPIN1 inhibits LPS-induced ferroptosis in podocytes by regulating the PI3K/AKT signaling pathway.

Diabetic kidney disease (DKD) is a prevalent microvascular complication of diabetes mellitus (DM) that significantly impairs patients' quality of life. Its early stage is characterized by glomerular filtration barrier damage and the occurrence of proteinuria. Without timely intervention, this condition progresses to renal fibrosis, and therapeutic options remain limited despite recent advances. Yitangkang decoction (YTK) has shown potential in ameliorating this barrier damage, thereby inhibiting proteinuria and ultimately preventing renal fibrosis; however, its precise mechanisms remain unclear. This study aimed to elucidate the therapeutic mechanism by which YTK ameliorates glomerular filtration barrier damage in DKD. db/db mice were treated with high-, medium-, or low-dose YTK or with finerenone for 8 weeks. We employed a multi-omics approach-including data-independent acquisition (DIA) proteomics, transcriptomics, and palmitoyl-proteomics coupled with LC-MS/MS-to identify differentially expressed proteins, mRNAs, and palmitoylation sites related to YTK's renoprotective effects, as well as to characterize its absorbed serum components. In vitro validation was performed in D-glucose-injured MPC5 podocytes, mouse renal microvascular endothelial cells and mouse glomerular mesangial cells using YTK-medicated serum, finerenone-medicated serum, the active components puerarin and quercitrin, or pharmacological modulators of the AMPK and TGF-β1 pathways. YTK's efficacy was evaluated using biochemical, histopathological, and molecular biological indicators. YTK treatment dose-dependently reduced urinary albumin-to-creatinine ratio (UACR), serum creatinine (Scr), urea, uric acid (UA), and lipid peroxide (LPO) levels, while restoring glutathione (GSH) levels and alleviating renal pathology in db/db mice. Multi-omics integration revealed enrichment in pathways involving extracellular matrix (ECM)-receptor interaction, AMPK signaling, and glutathione metabolism. YTK attenuated glomerular filtration barrier damage through several coordinated mechanisms: (1) Inhibition of the TGF-β/Smad pathway, downregulating TMEM2, TGF-β1, Smad2/3/4, and MMP-9; (2) Enhancement of SLC7A11 palmitoylation via the AMPKα1/ZDHHC8 axis, which stabilized SLC7A11 protein and inhibited ferroptosis-a role confirmed by site-directed mutagenesis of the critical Cys327 site; (3) Direct modulation of macrophage polarization, suppressing pro-inflammatory M1 markers and promoting anti-inflammatory M2 markers; and (4) Multi-target cytoprotection against renal cell injury. Surface plasmon resonance (SPR) analysis confirmed the direct, concentration-dependent binding of puerarin and quercitrin to GPX4 and TGF-β1. In vitro, YTK-medicated serum, puerarin, and quercitrin restored viability in injured MPC5 podocytes, renal microvascular endothelial cells and glomerular mesangial cells, induced consistent mRNA expression changes of key targets across both cell types, and inhibited apoptosis via modulation of the TGF-β/Smad and AMPK/SLC7A11 pathways. Specificity validation of the palmitoylation detection method reinforced the reliability of the omics findings. This study comprehensively elucidates the multi-cellular protective mechanism of YTK on the glomerular filtration barrier. We demonstrate that YTK confers protection via a dual-pathway mechanism: (1) Suppression of the injury pathway by inhibiting TGF-β1/Smad overactivation via modulation of macrophage phenotype and ECM homeostasis, thereby mitigating inflammation and cellular damage; and (2) Activation of the protective pathway by enhancing SLC7A11 palmitoylation through the AMPKα1/ZDHHC8 axis, which stabilizes SLC7A11, restores glutathione metabolism, and inhibits ferroptosis. These two axes functionally interact to rebalance injury and protective signaling. Furthermore, puerarin and quercitrin were identified as key serum-absorbed constituents that directly bind to targets including TGF-β1 and GPX4, mediating the described dual-pathway regulation. In summary, YTK represents a promising multi-target therapeutic strategy that coordinately regulates injury and protective signaling networks to prevent and alleviate proteinuria in DKD.

Low levels of reactive oxygen species and resulting oxidative protein modifications may play a beneficial role in cellular function under stress conditions. Here we studied the influence of age-dependent protein carbonylation on expression and activity of the anti-oxidative selenoenzyme glutathione peroxidase (GPx) in insulin-deficient Ins2 Protein carbonylation, GPx expression and activity were examined in kidney tissue and lysates by common histological and protein biochemical methods. In kidneys of Ins2 These results indicate the existence of a threshold for beneficial carbonylation-dependent redox signaling during the progression of diabetic nephropathy.

No abstract

Individuals living with metabolic syndrome (MetS) such as diabetes and obesity are at high risk for developing chronic kidney disease (CKD). This study investigated the beneficial effect of whole grape powder (WGP) diet on MetS-associated CKD. Obese diabetic ZSF1 rats, a kidney disease model with MetS, were fed WGP (5%,

Injection of rats with large doses of bovine serum albumin causes proteinuria which may persist long after the period of overload has ended. In order to assess in this model of proteinuria the relative importance of podocytic epithelial changes versus alterations in anionic groups in the glomerular capillary wall a morphological study has been made of animals in which the kidneys were fixed by vascular perfusion or by in situ drip fixation. By transmission electron microscopy, podocytes showed protein droplets, cytoplasmic vacuoles, spreading of epithelial cytoplasm with loss of foot processes, and focal separation of epithelium from the glomerular basement membrane, occasionally with cytoplasmic disruption. Staining with colloidal iron showed no reduction in the density of anionic groups per unit area on epithelial cell surfaces or elsewhere in glomeruli. However, the reduced surface area of epithelial cells caused by the changes to their structure accounts adequately for the less intense glomerular colloidal iron staining evident by light microscopy. Changes in podocyte structure, particularly those leading to focal cytoplasmic defects on the outer surface of the glomerular basement membrane, appear to be more important than loss of glomerular anionic groups for the development of proteinuria in protein overload nephropathy.

Clinical studies have demonstrated that some antihypertensive agents provide renoprotection independent of BP lowering. Recent in vitro and in vivo studies evaluated the mechanisms involved in this protection. First, the in vitro effects of several angiotensin II type 1 receptor blockers (ARB), calcium channel blockers (CCB), and beta blockers (BB) on various mediators were compared: Formation of pentosidine (an advanced glycation end product), hydroxyl radical-induced formation of o-tyrosine, and transition metals-induced oxidation of ascorbic acid (the Fenton reaction). All of the six tested ARB but neither the six CCB nor the nine BB inhibited pentosidine formation. ARB, as well as BB but not CCB, inhibited hydroxyl radicals-mediated o-tyrosine formation. ARB but neither BB nor CCB inhibited efficiently transition metals-catalyzed oxidation of ascorbic acid. Second, the in vivo consequences for the kidney of these various in vitro effects were evaluated. Hypertensive, type 2 diabetic rats with nephropathy, SHR/NDmcr-cp, were given for 20 wk either olmesartan (ARB) or nifedipine (CCB), or atenolol (BB). Despite similar BP reduction, only ARB significantly reduced proteinuria and prevented glomerular and tubulointerstitial damage (mesangial activation, podocyte injury, tubulointerstitial injury, and inflammatory cell infiltration). It is interesting that only ARB prevented abnormal iron deposition in the interstitium, corrected chronic hypoxia, reduced expressions of heme oxygenase and p47phox (a subunit of NADPHoxidase), and inhibited pentosidine formation (which correlates well with proteinuria). These observations confirm unique renoprotective properties of ARB, independent of BP lowering but related to decreased oxidative stress (hydroxyl radicals scavenging and inhibition of the Fenton reaction), correction of chronic hypoxia, and inhibition of advanced glycation end product formation and of abnormal iron deposition. These benefits of ARB may contribute to the renoprotection observed beyond BP lowering.

ETHNOPHARMACOLOGICAL RELEVANCE Diabetic kidney disease (DKD), a prevalent microvascular complication of diabetes, is a leading cause of end-stage renal disease (ESRD). Emerging evidence implicates ferroptosis in DKD pathogenesis. Qing-Re-Xiao-Zheng-(Yi-Qi) Formula (QRXZYQF), a traditional Chinese medicine with a 30-year clinical application history, exhibits multifaceted pharmacological benefits. But its potential role in DKD has yet to be fully investigated. AIM OF THE STUDY This study investigates whether QRXZYQF alleviates podocyte injury and mitigates DKD progression by modulating ferroptosis through AMP-activated protein kinase (AMPK) pathway activation. MATERIALS AND METHODS We induced DKD in male sprague dawley (SD) rats by performing left unilateral nephrectomy followed by a single intraperitoneal injection of streptozotocin (STZ, 50 mg/kg). Rats received QRXZYQF (12/24 g/kg), metformin (100 mg/kg), and valsartan (8 mg/kg) for 16 weeks. Renal function, blood glucose, lipid profiles, 24-hour urinary protein (24 h-UTP), oxidative stress markers glutathione (GSH) and malondialdehyde (MDA), and histopathology were assessed. In vitro, high-glucose-cultured conditionally immortalized mouse podocytes (MPC-5) cells were analyzed for cell viability assays, ferroptosis markers, mitochondrial integrity, and AMPK signaling. Additionally, we used short hairpin RNA (shRNA) to suppress AMPK expression to confirm whether QRXZYQF exerts protective effects on DKD via AMPK-mediated ferroptosis signaling. RESULTS QRXZYQF improved body weight, glucose-lipid metabolism, and renal function in DKD rats, and alleviated kidney tissue pathology, renal fibrosis and mitochondrial damage. Furthermore, QRXZYQF upregulated the expression of ferroptosis-related proteins glutathione peroxidase 4 (GPX4) and solute carrier family 7 member 11 (SLC7A11) while downregulating acyl CoA synthase long-chain family member 4 (ACSL4) expression, and attenuated oxidative stress. Moreover, AMPK silencing partially reversed QRXZYQF's protective effects, confirming AMPK-dependent ferroptosis inhibition. CONCLUSIONS QRXZYQF attenuates DKD progression by activating AMPK signaling, thereby suppressing podocyte ferroptosis. These findings underscore its potential as a therapeutic agent for DKD.

High fructose consumption is a significant risking factor for glomerular podocyte injury. However, the causes of high fructose-induced glomerular podocyte injury are still unclear. In this study, we reported a novel mechanism by which high fructose induced ferroptosis, a newly form of programmed cell death, in glomerular podocyte injury. We performed quantitative proteomic analysis in glomeruli of high fructose-fed rats to identify key regulating proteins involved in glomerular injury, and found that mitochondrial single-strand DNA-binding protein 1 (SSBP1) was markedly upregulated. Depletion of SSBP1 could alleviate high fructose-induced ferroptotic cell death in podocytes. Subsequently, we found that SSBP1 positively regulated a transcription factor p53 by interacting with DNA-dependent protein kinase (DNA-PK) and p53 to drive ferroptosis in high fructose-induced podocyte injury. Mechanically, SSBP1 activated DNA-PK to induce p53 phosphorylation at serine 15 (S15) to promote the nuclear accumulation of p53, and thereby inhibited expression of ferroptosis regulator solute carrier family 7 member 11 (SLC7A11) in high fructose-exposed podocytes. Natural antioxidant pterostilebene was showed to downregulate SSBP1 and then inhibit DNA-PK/p53 pathway in its alleviation of high fructose-induced glomerular podocyte ferroptosis and injury. This study identified SSBP1 as a novel intervention target against high fructose-induced podocyte ferroptosis and suggested that the suppression of SSBP1 by pterostilbene may be a potential therapy for the treatment of podocyte ferroptosis in glomerular injury.

Background Ferroptosis plays an important role in the development of diabetic nephropathy (DN). However, its specific regulatory mechanisms remain unclear. Methods MPC5 cells were cultured in high glucose (HG) medium to stimulate the HG environment in vitro. Ferroptosis and oxidative stress were assessed by measuring malondialdehyde (MDA) levels, cystine uptake capacity, and reactive oxygen species (ROS). C91A and wild type (WT) MPC5 cells were constructed to further explore the specific regulatory mechanism of BAP1 on SLC7A11. Results Erastin-induced ferroptosis was sensitized by HG, leading to a significant reduction in glutathione (GSH) levels, increased oxidative stress, and inhibited cystine uptake in podocytes. HG suppressed the expression of SLC7A11. Overexpression of SLC7A11 improved cystine uptake and reduced oxidative stress. Furthermore, HG increased BAP1 levels. Silencing BAP1 up-regulated SLC7A11 and mitigated ferroptosis. Cell proliferation was reduced after SLC7A11 knockdown. In BAP1 WT cells, but not in its C91A mutant cells, the transcription of SLC7A11 was downregulated and the level of ferroptosis was increased. Conclusion HG inhibits cystine uptake in podocytes by promoting the expression of BAP1 and inhibiting H2Aub deubiquitination on SLC7A11, leading to lipid peroxide accumulation and ferroptosis in podocytes.

No abstract available

Ferroptosis is a newly discovered form of cell death characterized by intracellular iron accumulation and subsequent lipid peroxidation, which has been identified in various pathological processes, such as acute kidney injury (AKI). Ulinastatin (UTI), known as an antioxidant and anti-inflammatory, has been reported to prevent kidney injury. Here, we investigated the protective effects of UTI on LPS-induced podocyte ferroptosis in vivo and in vitro. Conditionally immortalized mouse podocyte was exposed to LPS in the presence or absence of UTI in vitro for 48 h. The levels of reactive oxygen species (ROS) and intracellular Fe2+ were detected to value the effect of UTI treatment on the podocyte cell ferroptosis. We also evaluated the influence of UTI on kidney injury in vivo. LPS-induced mice were treated with vehicle or UTI at 50 U/g/d for 6 wk. We identified the important function of UTI in repressing ferroptosis and ameliorating podocyte injury. The treatment of UTI reduced accumulation of Fe2+ and lipid ROS in podocyte. The cell proliferation was induced by UTI compared with the LPS-treated group in vitro. UTI attenuated the podocyte cytoskeletal as well. Regarding the mechanism, we found that UTI upregulated solute carrier family 7 member 11 (SLC7A11) expression by reducing miR-144-3p in the cells. The overexpression of miR-144-3p blocked the protective role of UTI in podocyte ferroptosis. MiR-144-3p/SLC7A11 axis was involved in UTI-mediated podocyte cell proliferation in vitro. Furthermore, the treatment of UTI repressed podocyte injury and proteinuria in vivo, and the level of miR-144-3p was decreased while SLC7A11 expression was increased in comparison with the model mice. UTI prevents LPS-induced podocyte ferroptosis and subsequent renal dysfunction through miR-144-3p/SLC7A11 axis. These findings might provide a potential novel therapeutic option for AKI and other renal diseases affecting podocyte.

No abstract available

No abstract available

ETHNOPHARMACOLOGICAL RELEVANCE Membranous nephropathy (MN) is a primary glomerular disease and a major cause of nephrotic syndrome in adults. According to traditional Chinese medicine (TCM) theory, "dampness" is considered a key pathogenic factor. Sanqi Qushi Formula (SQQS), developed by adding dampness-eliminating herbs to Sanqi Oral Liquid, has been shown to improve remission rates in idiopathic MN, although its pharmacological mechanisms are not yet fully clarified. AIM OF THE STUDY This study investigated whether SQQS attenuates podocyte injury in MN by inhibiting endoplasmic reticulum stress (ERS)-induced ferroptosis. METHODS The main components of SQQS were identified and quantified by widely targeted metabolomics. A passive Heymann nephritis (PHN) rat model was established via intravenous injection of anti-Fx1A serum, followed by oral SQQS intervention. Renal function and histopathology were evaluated, and underlying mechanisms were investigated by integrating transcriptomic and proteomic analyses. Structural changes in the endoplasmic reticulum and mitochondria were assessed by transmission electron microscopy. The regulatory effect of SQQS on ERS-induced ferroptosis was further examined using immunohistochemistry, flow cytometry, oxidative stress assays, and related molecular analyses. In vitro, immortalized mouse podocytes MPC-5 were injured with zymosan-activated serum and treated with SQQS-containing serum, the ferroptosis inhibitor Fer-1, the ERS inhibitor 4-PBA, or the ERS activator tunicamycin. The protective effects of SQQS were validated by Western blotting and immunofluorescence. RESULTS SQQS treatment significantly improved renal function, reduced proteinuria, and alleviated glomerular injury in PHN rats. Histopathological and ultrastructural analyses revealed that SQQS reduced glomerular IgG deposition, basement membrane thickening, fibrosis, and podocyte injury. SQQS dose-dependently restored the expression of key podocyte structural proteins (Nephrin, Synaptopodin, Podocin, α-actinin-4, WT-1) and decreased Desmin levels. Integrated transcriptomic and proteomic analyses identified ERS and ferroptosis as central pathways regulated by SQQS. SQQS suppressed ERS markers (GRP78, p-PERK, p-eIF2α, ATF4, CHOP) and pro-ferroptotic proteins (ACSL4, CHAC1), upregulated antioxidant proteins (GPX4, xCT), reduced iron deposition, and attenuated oxidative stress. In vitro, SQQS-containing serum protected MPC-5 podocytes from ZAS-induced ferroptosis by inhibiting ERS, restoring podocyte marker expression, and enhancing antioxidant defenses. CONCLUSION SQQS ameliorates MN by inhibiting the ERS-ferroptosis axis, providing experimental and theoretical support for the application of TCM in the treatment of MN.

This study investigated whether ginkgolide B alleviates renal and podocyte injury in membranous nephropathy by inhibiting ferroptosis. Rats with passive Heymann nephritis received ginkgolide B (7.5 mg/kg/day) or vehicle. Ginkgolide B significantly ameliorated nephrotic syndrome, reducing 24-hour urinary protein excretion, and improving serum albumin levels. It also normalized lipid profiles and enhanced renal function, with all changes achieving statistical significance at p<0.05. Histopathological analysis revealed reduced glomerular immune deposits, preserved podocyte density indicated by improved WT-1 nuclear expression/distribution, and restored slit diaphragm integrity shown by increased CD2AP expression. Mechanistically, ginkgolide B suppressed ferroptosis by significantly decreasing reactive oxy-gen species and lipid peroxides, reducing iron deposition, downregulating ferroptosis drivers NCOA4, ACSL4, and LPCAT3, and restoring glutathione peroxidase 4 activity (p<0.05 for all). These findings demonstrate that ginkgolide B mitigates membranous nephropathy-associated renal and podocyte injury by inhibiting ferroptosis.

Ferroptosis, an iron-dependent form of cell death characterized by lipid peroxidation, has been recognized as a critical mechanism contributing to podocyte injury in diabetic kidney disease (DKD). Although interferon-stimulated gene 20 (ISG20) has been identified as a novel regulator of RNA oxidation stress in acute kidney disease, its specific role and mechanism in DKD remain to be elucidated. In this study, we investigated the role of ISG20 in ferroptosis and its potential as a therapeutic target in DKD. We found that ISG20-deficient mice exhibited excessive iron accumulation, increased lipid peroxidation, and markedly higher proteinuria compared to wild-type mice. Nevertheless, the administration of a ferroptosis inhibitor, ferrostatin-1(Fer-1), mitigated kidney injury. Consistent results were observed in vitro, where the detrimental effects of ISG20 gene silencing could be mitigated by Fer-1 treatment in mouse podocytes under high glucose (HG) conditions. To further investigate the protective effects of ISG20, we administered two distinct vectors into diabetic mice: an adenovirus vector overexpressing ISG20 and a novel mRNA-loaded lipid nanoparticle (LNP) therapeutic vector expressing ISG20 mRNA. Both approaches effectively mitigated podocyte ferroptosis, alleviated podocyte injury, and reduced proteinuria in DKD. Similar results were also found in mice with adriamycin-induced nephropathy. Overall, this study establishes that ISG20 safeguards podocyte viability by suppressing ferroptosis, which extends ISG20’s biological role. These findings suggest that ISG20 may be a potential therapeutic strategy for treating patients with proteinuric kidney disease.

BACKGROUND The Sanqi Qushi Formula (SQQS) is a traditional Chinese medicine comprising seven herbs, namely Astragali Radix, Curcumae Rhizoma, Notoginseng Radix Et Rhizoma, Radix Padoniae Rubra, Smilacis Glabrae Rhizoma, Atractylodis Macrocephalae Rhizoma, and Cordyceps Sinensis. While SQQS is widely used in clinics to treat membranous nephropathy (MN), the molecular mechanisms responsible for its therapeutic effects remain unclear. PURPOSE This study sought to explore the nephroprotective activity of SQQS, as well as its molecular mechanism in treating MN. METHODS The nephroprotective effects of SQQS were assessed in experimental Passive Heymann nephritis (PHN) rats. The chemical components of SQQS's freeze-dried powder and rat plasma were identified using UPLC-Q-Exactive-MS. For the mechanism exploration, network pharmacology was integrated with RNA-seq transcriptomics to explore its underlying multi-dimensional correlations. To investigate whether SQQS could alleviate podocyte damage by inhibiting GPX4 deficiency-mediated ferroptosis, a RSL3-induced podocyte model was established. The protein expression in the candidate signaling pathway was evaluated. Molecular docking experiments, molecular dynamics simulation analyses (MDS), bioactivity tests, and surface plasmon resonance technology (SPR) were conducted to explore the pharmacodynamic molecule of SQQS. RESULTS SQQS administration significantly ameliorated 24 h proteinuria, elevated serum albumin (ALB), and reduced the levels of serum creatinine (Scr), blood urea nitrogen (BUN), and total cholesterol (TC). Besides, SQQS alleviated glomerular pathological damage in PHN rats, decreased IgG and C3 deposition, and reversed the aberrant expression of podocyte damage-related protein. Moreover, SQQS treatment alleviated mitochondrial injury, upregulated the levels of glutathione peroxidase 4 (GPX4), cystine/glutamate antiporter xCT, glutathione (GSH), and superoxide dismutase (SOD), and reduced malondialdehyde (MDA) content and Acyl-CoA synthetase long chain-family member 4 (ACSL4) expression, as well as iron deposition in PHN rats. A total of 248 compounds were detected in the freeze-dried powder of SQQS, with 105 compounds identified in the rat plasma, of which 41 components were common to both in vitro and in plasma samples. Integrative investigations using network pharmacology and RNA-seq transcriptomics identified the JNK/FoxO1/GPX4 signaling pathway as a candidate therapeutic target. Further studies exhibited that SQQS reduced nuclear FoxO1 and p-JNK, and elevated p-FoxO1 and total FoxO1. In vitro experiments with SQQS-containing serum (SQQSCS) increased cell viability and reduced Fe2+ levels, oxidative stress, lipid peroxidation, and mitochondrial injury. Furthermore, our results indicated that SQQSCS yielded a significant regulatory effect on the proteins of the JNK/FoxO1/GPX4 signaling pathway. A core protein intervention experiment showed that SQQS promotion of GPX4 expression was related to the nuclear translocation of FoxO1, regulated by p-JNK. Finally, molecular docking, molecular dynamics simulations, bioactivity tests, and SPR studies showed that Baicalein and Paeoniflorin, two major compounds in SQQS, upregulated the expression of GPX4 to inhibit ferroptosis in PHN rats by targeting JNK1. CONCLUSIONS These results suggest that SQQS may alleviate podocyte damage by inhibiting GPX4 deficiency-mediated ferroptosis through targeting JNK1 to decrease the nuclear translocation of FoxO1.

Tanshinone IIA (TIIA) is one of the main components of the root of the red‐rooted Salvia miltiorrhiza Bunge. However, the molecular mechanisms underlying TIIA‐mediated protective effects in diabetic nephropathy (DN) are still unclear.

Aims: Diabetic kidney disease (DKD) is the leading cause of end-stage kidney disease, and podocyte injury is one of the major contributors to DKD. As a crucial transcriptional factor that regulates cellular response to oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) is an attractive therapeutic target for DKD. In this study, we evaluated the therapeutic potential of DDO-1039, a novel small-molecule Nrf2 activator developed with protein–protein interaction strategy, on podocyte injury in DKD. Results: DDO-1039 treatment significantly increased Nrf2 protein level and Nrf2 nuclear translocation, thereby upregulating Nrf2 target genes [heme oxygenase 1, NAD(P)H quinone dehydrogenase 1, glutamate-cysteine ligase modifier, and tyrosine-protein kinase receptor] both in vitro and in vivo. DDO-1039 attenuated glomerular sclerosis and podocyte injury in the high-fat diet/streptozotocin-induced (HFD/STZ) diabetic mice and db/db diabetic mice. It also significantly improved hyperglycemia in both diabetic mice and mitigated proteinuria in HFD/STZ mice. Meanwhile, DDO-1039 attenuated oxidative stress and inflammation as well as apoptosis in vivo and in podocytes stimulated with palmitic acid and high glucose. Interestingly, we identified podocyte protective factor Tyro3 as a novel Nrf2-regulated gene. In addition, podocyte ferroptosis is reduced via activation of glutathione peroxidase 4 by the novel Nrf2 activator. Innovation and conclusion: DDO-1039 activates the Nrf2-based cytoprotective system to mitigate podocyte injury in the context of diabetes, suggesting the potential of DDO-1039 in the treatment of DKD. Antioxid. Redox Signal. 42, 787–806.

Glomerular podocyte damage is considered to be one of the main mechanisms leading to Diabetic nephropathy (DN). However, the relevant mechanism of podocyte injury is not yet clear. This study aimed to investigate the effect of peroxiredoxin 6 (Prdx6) on the pathogenesis of podocyte injury induced by high glucose (HG). The mouse glomerular podocyte MPC5 was stimulated with 30 nM glucose, and the Prdx6 overexpression vector or specificity protein 1 (Sp1) overexpression vector was transfected into MPC5 cells before the high glucose stimulation. As results, HG treatment significantly reduced the expression of Prdx6 and Sp1 in MPC5 cells. Prdx6 overexpression increased cell viability, while inhibited podocyte death, inflammation and podocyte destruction in HG-induced MPC5 cells. Prdx6 overexpression inhibited HG-induced ROS and MDA production, while restored SOD and GSH activity in MPC5 cells. Prdx6 overexpression also eliminated ferroptosis caused by HG, which was reflected in the suppression of iron accumulation and the increase in SLC7A11 and GPX4 expression. The improvement effect of Prdx6 on HG-induced podocyte damage could be eliminated by erastin. Moreover, Sp1 could bind to the three Sp1 response elements in the Prdx6 promoter, thereby directly regulating the transcriptional activation of Prdx6 in podocytes. Silencing Sp1 could eliminate the effect of Prdx6 on HG-induced podocyte damage. Further, Prdx6 overexpression attenuated renal injuries in streptozotocin-induced DN mice. Sp1-mediated upregulation of Prdx6 expression prevents podocyte injury in diabetic nephropathy via mitigation of oxidative stress and ferroptosis, which may provide new insights for the study of the mechanism of DN.

We explored the protection of mangiferin monosodium salt (MGM) on kidney injury in rats with streptozotocin (STZ)-induced diabetic nephropathy (DN) by "multiomics" analysis combined with systems pharmacology, with a specific focus on ferroptosis, inflammation, and podocyte insulin resistance (IR) signaling events in kidneys. MGM treatment afforded renoprotective effects on rats with STZ-induced DN by alleviating systemic IR-induced renal inflammation and podocyte IR. These mechanisms were correlated mainly with the MGM treatment-induced inhibition of the mitogen-activated protein kinase/nuclear factor-kappa B axis and activation of the phosphorylated insulin receptor substrate 1(Tyr608)/phosphorylated phosphatidylinositol 3-kinase/phosphorylated protein kinase B axis in the kidneys of DN rats. MGM had an ameliorative function in renal ferroptosis in rats with STZ-induced DN by upregulating mevalonate-mediated antioxidant capacities (glutathione peroxidase 4 and ferroptosis suppressor protein 1/coenzyme Q10 axis) and weakening acyl-CoA synthetase long-chain family member 4-mediated proferroptotic generation of lipid drivers in kidneys. MGM may be a promising alternative strategy for the treatment of DN.

Objective Lupus nephritis (LN) is a major cause of kidney failure in systemic lupus erythematosus, with podocyte injury being a key determinant of proteinuria and poor renal outcome. Ferroptosis, an iron-dependent form of regulated cell death, has been implicated in kidney diseases, but its role in LN remains unclear. Methods We integrated in vivo experiments using MRL/lpr mice, in vitro assays with immortalized podocytes (MPC5), and transcriptomic analysis of human glomerular datasets (GSE32591). Ferroptosis involvement was evaluated by ferrostatin-1 (Fer-1) treatment, measurement of ferroptosis markers, and assessment of podocyte proteins. Bioinformatic analyses (differential expression, WGCNA, LASSO regression, and FerrDb integration) identified candidate ferroptosis regulators, followed by functional validation of CYBB via siRNA knockdown and overexpression. Results Progressive nephritis in MRL/lpr mice showed iron overload, lipid peroxidation, glutathione depletion, and GPX4 downregulation, leading to podocyte loss and proteinuria. Fer-1 treatment markedly ameliorated renal pathology and preserved podocyte integrity. Human LN datasets identified CYBB as a ferroptosis-related hub gene upregulated in disease. CYBB expression correlated with renal dysfunction and oxidative injury, while in vitro assays confirmed that CYBB overexpression enhanced ROS generation and ferroptotic podocyte damage, whereas CYBB knockdown or Fer-1 reversed these effects. Conclusion These findings identify CYBB-mediated ferroptosis as a key driver of podocyte injury in LN. By promoting ROS generation and lipid peroxidation, CYBB serves as a mechanistic link between oxidative stress and ferroptotic cell death. Both pharmacological and genetic inhibition of CYBB mitigated ferroptosis, preserved podocyte integrity, and improved renal function, highlighting CYBB as a promising therapeutic target in lupus nephritis.

Diabetic kidney disease (DKD) is a leading cause of chronic kidney disease worldwide, and podocyte ferroptosis plays a crucial role in its pathogenesis. Hirsutine (HS) reduces blood glucose levels and improve insulin resistance in diabetic mice, suggesting its potential use in diabetes treatment. Here, we established a db/db mouse model of DKD and administered HS for 8 weeks. We found that HS decreased the concentrations of iron, reactive oxygen species (ROS), and malondialdehyde (MDA) in renal tissues. Furthermore, HS treatment restored mitochondrial morphology, increased Glutathione Peroxidase 4(GPX4) levels, and decreased p53 levels, alleviating podocyte loss in the DKD mouse model. However, the effects of HS were reversed by the p53 activator Nutlin-3. Therefore, we propose HS may mitigate podocyte injury in DKD by regulating the p53/GPX4 pathway, providing a novel strategy for targeting podocyte ferroptosis in DKD.

ETHNOPHARMACOLOGICAL RELEVANCE Swietenia macrophylla King is a traditional medicinal plant extensively utilized in Asia and its pharmacological properties primarily involve antidiabetic, anti-inflammatory, antioxidant, antibacterial, and antitumor effects. Swietenine (Swi), the major bioactive compound presents in the fruits of S. macrophylla, has demonstrated beneficial therapeutic effects on diabetic nephropathy (DN). However, the underlying mechanism through which Swi influences DN remains unclear. AIM OF THE STUDY The current research aims to investigate the effects of Swi on DN and explore its underlying mechanisms associated with ferroptosis, both in vivo and in vitro. METHODS A model of streptozotocin/high-fat diet (STZ/HFD)-induced Sprague-Dawley (SD) rats was employed to assess the effect of Swi on improving DN and resisting ferroptosis in vivo. Additionally, mouse podocyte cells (MPC-5 cells) were induced by high glucose (HG) and cultured to explore the potential mechanisms of Swi in treating DN in vitro. To further validate the protective effects of Swi, pathway-specific inhibitors were administered to HG-induced MPC-5 cells to confirm the involvement of the Akt/GSK-3β/Nrf2 signaling pathway in the inhibition of ferroptosis. A combination of proteomics, immunohistochemical staining, western blotting, and cell culture techniques was utilized to explore the pharmacological mechanisms of Swi. Furthermore, network pharmacology and molecular docking analyses were conducted to predict the targets of Swi in relation to DN, which were subsequently validated through Western blotting analysis. RESULTS Administration of Swi significantly enhanced renal function and ameliorated pathological alterations in DN rats, as well as improved oxidative stress and inhibited ferroptosis. In vitro studies revealed that Swi dramatically improved the cell viability and mitigated oxidative stress, and inhibited ferroptosis via activating the Akt/GSK-3β/Nrf2 signaling pathway in HG-induced MPC-5 cells. CONCLUSION This study demonstrates that Swi improves DN by inhibiting ferroptosis via activating Akt/GSK-3β/Nrf2 signaling pathway for the first time, thereby providing a scientific basis that Swi is expected to be a promising candidate drug for the treatment of DN.

BACKGROUND Ferroptosis has been reported to be involved in the occurrence and development of various kidney diseases. Emerging evidence suggests that ferroptosis also plays a critical role in systemic lupus erythematosus (SLE) and lupus nephritis (LN), contributing to podocyte injury and renal dysfunction. Mesenchymal stromal cells (MSCs) have become an attractive option for podocyte injury repairing in LN. The aim of this research was to determine whether MSCs regulate ferroptosis of podocytes in LN. METHODS MSCs were injected into female MRL/lpr mice via tail vein. The symptoms of LN and the detection of ferroptosis-related biomarkers in podocytes were detected. In vitro validation was conducted by mouse podocyte cell line MPC-5. RESULTS The occurrence of ferroptosis and involvement of Nrf2/heme oxygenase-1 (HO-1) signaling pathway in podocytes were observed. We found increased expression of the podocyte marker, Wilm's tumor 1 (WT-1) and synaptopodin, following the improvement of lupus-like symptoms after MSC transplantation in MRL/lpr mice. The expression of ferroptosis-related protein glutathione peroxidase 4 (GPX4) and long chain acyl-CoA synthetase 4 (ACSL4) were elevated in renal, along with the Nrf2 and HO-1 activity enhancement. In vitro, MSC treatment maintain a stabilization of podocyte actin stress fibers, leading to an improvement of cell viability. Furthermore, our results showed that puromycin aminonucleoside (PAN) induce accumulation of cellular lipid reactive oxygen species (ROS) and glutathione depletion, and the expression of Nrf2, HO-1 and GPX4 were all downregulated whereas the expression of ACSL4 was upregulated. However, these effects were reversed by MSCs and ferroptosis inhibitor ferrastatin-1 (Fer-1). The promotion of Nrf2 nuclear translocation was observed after the treatment with MSCs. CONCLUSION Ferroptosis activation is involved in the development of LN. MSCs could ameliorate podocyte injury in LN by inhibiting ferroptosis through the Nrf2/HO-1/GPX4 pathway, which will provide novel potential therapeutic targets for LN.

Background: Hepatitis B virus associated-glomerulonephritis (HBV-GN) is one of the major secondary renal diseases in China, and microRNAs (miRNAs) in bone marrow mesenchymal stem cell-derived exosomes (BMSC-Exo) can attenuate HBV-X protein (HBx)-induced ferroptosis in renal podocytes, but the exact mechanism remains unclear. This study aimed to investigate the protective mechanism of miR-223-3p in BMSC-Exo in HBx-induced ferroptosis in podocytes. Methods: The study employed human renal podocyte cells (HPCs), bone marrow-derived mesenchymal stem cells (BMSCs), as well as kidney tissue from C57BL/6 mice and HBx transgenic mice. Initially, the correlation between STAT3 phosphorylation and ferroptosis was authenticated through the administration of signal transducer and activator of transcription 3 (STAT3) phosphorylation inhibitors in both in vivo and in vitro settings. Furthermore, the effect of HDAC2 overexpression on STAT3 phosphorylation was examined. Subsequently, the association between BMSC-Exo carrying miR-223-3p, HDAC2, and the phosphorylation of STAT3 in HPCs ferroptosis and injury induced by HBx was assessed. The interaction between miR-223-3p and HDAC2 was confirmed via RNA immunoprecipitation assay. Various techniques such as cell counting kit-8 assay, western blot, RT-qPCR, immunofluorescence, flow cytometry, lipid peroxidation assay kit, iron assay kit, transmission electron microscopy, and hematoxylin-eosin staining were employed to visualize the extent of HBx-induced podocyte injury and ferroptosis in both in vivo and in vitro. Results: The attenuation of podocyte ferroptosis can be achieved by inhibiting the phosphorylation of STAT3 in podocytes induced by HBx. Conversely, the upregulation of HDAC2 can enhance STAT3 phosphorylation, thereby promoting podocyte ferroptosis. MiR-223-3p was capable of directly exerting negative regulation on HDAC2 expression. BMSC-Exo carrying miR-223-3p can effectively suppress the expression of HDAC2, ultimately leading to reduce HBx-induced ferroptosis in podocytes by targeting HDAC2 with miR-223-3p and downregulating STAT3 phosphorylation. Conclusion: This study evidences the potential of BMSC-Exo mediated delivery of miR-223-3p in mitigating HBx-induced ferroptosis in podocytes, thereby offering a novel therapeutic target and approach for treating HBV-GN and alleviating renal injury.

Abstract Objective Sirt6, reactive oxygen species and ferroptosis may participate in the pathogenesis of Diabetic Nephropathy (DN). Exploring the relationship between Sirt6, oxidative stress, and ferroptosis provides new scientific ideas to DN. Methods Human podocytes were stimulated with 30 mM glucose and 5.5 mM glucose. The mice of db/db group were randomly divided into two groups:12 weeks and 16 weeks. Collect mouse blood and urine specimens and renal cortices for investigations. HE, Masson, PAS and immunohistochemical staining were used to observe pathological changes. Western blot, RT-qPCR and immunofluorescence staining were used to evaluate expression of relevant molecules. CCK8 method was introduced to observe cell viability. The changes of podocyte mitochondrial membrane potential and mitochondrial morphology in each group were determined by JC-1 staining and Mito-Tracker. Results The expression level of Sirt6, Nrf2, SLC7A11, HO1, SOD2 and GPX4 were reduced, while ACSL4 was increased in DN. Blood glucose, BUN, Scr, TG, T-CHO and 24h urine protein were upregulated, while ALB was reduced in diabetic group. The treatment of Ferrostatin-1 significantly improved these changes, which proved ferroptosis was involved in the development of DN. Overexpression of Sirt6 might ameliorate the oxidation irritable reaction and ferroptosis. Sirt6 plasmid transfection increased mitochondrial membrane potential and protected morphology and structure of mitochondria. The application of Sirt6 siRNA could aggravated the damage manifestations. Conclusion High glucose stimulation could decrease the antioxidant capacity and increase formation of ROS and lipid peroxidation. Sirt6 might alleviate HG-induced mitochondrial dysfunction, podocyte injury and ferroptosis through regulating Nrf2/GPX4 pathway.

Arsenic and bisphenol A (BPA) are widespread environmental pollutants. We have studied the nephrotoxicity of arsenite (ARS), 10 mg/L in drinking water, plus BPA, 50 µg/kg oral dose, in juvenile Sprague-Dawley rats. Animals were randomized into seven groups and exposed to the chemicals either continuously or intermittently, for 8 weeks. The parameters evaluated were urine biomarkers, histopathological and transmission electron microscopic (TEM) examinations, DNA damage (halo assay), and protein expressions. Continuous exposure to AS and BPA significantly increased urinary creatinine, albumin, and total protein, and decreased blood urea nitrogen (BUN). Histopathological and TEM data showed brush border detachment, iron accumulation, podocyte injury, increased slit diaphragm space, and collagen deposition in both exposure groups. Significantly greater DNA damage was seen in the combined-exposure group than in the other experimental groups. Combination exposure in the continuous and intermittent groups showed renal fibrosis and ferroptosis and gene expression analysis revealed a significant increase in Bax and decrease in SIRT 1. Combination exposure was more harmful than the individual exposures in causing kidney injury in these animals.

Diabetic kidney disease (DKD) is a main cause of end-stage renal disorder, yet its pathogenesis is still incompletely understood. Ferroptosis has been implicated in DKD progression; however, its regulatory mechanisms remain unclear. Phosphoglycerate dehydrogenase (PHGDH), a key enzyme in serine biosynthesis, has been minimally studied in DKD development. To elucidate the roles of PHGDH in ferroptosis and its underlying mechanism in podocytes and DKD, we conducted this study. Our findings demonstrate that PHGDH deficiency exacerbates podocyte injury, characterized by cytoskeletal disorganization, and promotes ferroptosis in both podocytes and DKD renal tissues. Conversely, PHGDH overexpression alleviates podocyte injury, reduces ferroptosis, and improves renal function in DKD mice. Mechanistically, we identified that PHGDH mediates ferroptosis by regulating SLC7A11 expression, a key ferroptosis-related protein. Specifically, PHGDH stabilizes Y-box binding protein 1 (YB1) by inhibiting its K48-linked ubiquitination and degradation, thereby enhancing SLC7A11 mRNA stability and expression. In conclusion, our study reveals a novel PHGDH-YB1-SLC7A11 regulatory axis that is responsible for suppressing ferroptosis and protecting against podocyte and renal injury in DKD. Our findings shed new light into the molecular mechanism underlying ferroptosis in DKD and highlight PHGDH as a therapeutic target for mitigating ferroptosis-mediated renal damage.

Objectives: We aimed to explore the protective role of apigenin (API) and its underlying mechanisms in angiotensin II (Ang II)-induced hypertensive renal injury using both in vivo and in vitro models. Methods: In this study, we developed an Ang II-induced hypertensive renal injury mouse model and a recombinant IFN-γ-triggered murine podocyte clone 5 (MPC5) model in vitro. Results: API treatment reduced serum creatinine (Scr), blood urea nitrogen (BUN), and serum cystatin C (Cys-C) levels in Ang II-infused mice (all, P < .001). API reduced renal fibrosis and the expression of related molecules, including collagen I, collagen IV, fibronectin, transforming growth factor beta 1 (TGF-β1), and α-smooth muscle actin (α-SMA) (all, P < .001). The p-P13 K and p-Akt protein expression levels were improved by API treatment. API decreased the apoptotic rate, malondialdehyde (MDA) content, and mitochondrial ferrous iron, while increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), which were reversed by treatment with the PI3K/Akt pathway inhibitor LY294002 (all, P < .001). In addition, API treatment reduced the expression of glutathione peroxidase 4 (GPX4) while enhancing SLC7A11 and ACSL4 expression, which was reversed by LY294002 treatment (all, P < .001). Conclusion: Our experimental data suggest that API inhibits cell ferroptosis by activating the PI3K/Akt pathway and alleviates renal injury caused by hypertension. Graphical Abstract

Background Diabetic nephropathy (DN) is a severe complication in patients with diabetes mellitus, which is mainly characterized by glomerular podocyte injury. Ferroptosis is crucial in the pathogenesis of DN. Moringa oleifera leaf extract (MOLE) has attracted attention due to its multiple pharmacological activities, but it is unclear whether it can delay the progression of DN by inhibiting ferroptosis. Objectives To investigate whether MOLE can alleviate podocyte injury and delay the progression of DN by inhibiting ferroptosis. Materials and Methods DN model cells were established using rat podocytes induced by high glucose (HG); the cells were processed with MOLE, dapagliflozin (DAPA, positive control), and acyl-CoA synthetase long-chain family member 4 (ACSL4) overexpression plasmids. Cell viability, Fe2+ concentration, reactive oxygen species (ROS), malondialdehyde (MDA), and glutathione (GSH) levels were monitored by Cell Counting Kit-8 (CCK-8) and corresponding kits. Results MOLE treatment markedly enhanced HG-induced rat podocyte viability, decreased intracellular Fe2+ concentration, ROS level, MDA concentration, and elevated GSH concentration. ACSL4 overexpression reversed the protective effect of MOLE on podocytes. Conclusion MOLE ameliorates rat podocyte injury and delays DN progression by inhibiting ACSL4-mediated ferroptosis. This finding provides a theoretical basis for further developing MOLE-based therapeutic agents for DN treatment.

Podocytopathy is an emerging global health concern characterized by the injury of podocytes through various direct or indirect mechanisms. Recent research has highlighted a potential link between podocyte loss and various programmed cell death pathways, while the precise mechanisms of podocyte injury remain ambiguous. We conducted single-nucleus RNA sequencing (snRNA-seq) on kidney tissues from adriamycin-induced nephropathy (AN) mice (BALB/c, male) and renal biopsy samples from patients with different types of podocytopathy, such as focal segmental glomerulosclerosis (FSGS), minimal change disease (MCD) and obesity-related glomerulopathy (ORG). We found podocytes in diseased groups exhibited elevated ferroptosis scores based on the gene module score of programmed cell death pathways. Targeted lipidomics analysis revealed high phospholipids (PLs) levels containing long-chain polyunsaturated fatty acyl (LC-PUFA) tails. Metabolic pathway activity analysis indicated dysregulation of fatty acid elongation in podocytes of the AN group. We further reveal that the upregulation of Elovl7 in injured podocytes led to the accumulation of PLs with LC-PUFA tails, resulting in heightened sensitivity to ferroptosis. The results were confirmed by podocyte specific Elovl7 knockout mice and Elovl7 knockdown podocyte cell line. In conclusion, our study visualized injured podocytes and substantial podocyte loss from multiple podocytopathies. This phenomenon could potentially be attributed to the increased synthesis of LC-PUFAs facilitated by Elovl7, which leads to accumulation of intracellular lipid peroxidation and ultimately leading to ferroptosis.

Diabetic kidney disease (DKD) is a prominent etiological factor underlying the onset of end-stage kidney disease, which is characterized by the presence of microalbuminuria. Recent studies have found that high glucose can induce mitochondrial dysfunction and ferroptosis in podocytes, leading to renal impairment and proteinuria. Triptolide was extracted from traditional Chinese medicine Tripterygium wilfordii Hook F., which has anti-inflammatory, anti-oxidant, and podocyte protective activities. Multiple studies have shown that triptolide can ameliorate proteinuria in DKD. However, the specific mechanisms remain unclear. This study investigates whether triptolide can reverse proteinuria in DKD by inhibiting ferroptosis in db/db mice and its specific protective mechanisms. The results demonstrate that triptolide could preserve podocytes and reduce proteinuria in db/db mice via inhibiting ferroptosis. In vivo and in vitro, the expression of glutathione peroxidase 4 (GPX4), ferritin heavy chain 1 (FTH-1), and the cystine/glutamate reverse antiporter solute carrier family 7 member 11 (SLC7A11) were increased, and the production of transferrin receptor 1 (TFR-1) was decreased by triptolide. Moreover, triptolide suppressed oxidative stress and mitochondria dysfunction. Additionally, triptolide up-regulated the expression of NFE2-related factor 2 (Nrf2) and change the expression of its downstream targets related to ferroptosis. Furthermore, the podocyte actin cytoskeleton was stabilized by triptolide, and the transition from slit diaphragm (SD) to tight junction (TJ), which is a pivotal character of filtration barrier damage, was attenuated by triptolide. In conclusion, our results suggest that triptolide could stabilize the glomerular podocyte cytoskeleton and attenuate renal SD-TJ transition in DKD by upregulating Nrf2 and thereby inhibiting ferroptosis.

BACKGROUND Diabetic nephropathy (DN) represents approximately 50 % of all chronic kidney disease cases. Given the established involvement of USP22 in DN progression, this study investigated its underlying regulatory mechanisms. METHODS Mouse podocytes were treated with high glucose (HG), and a diabetic mouse model was established. Podocyte viability and apoptosis were assessed by CCK-8 and TUNEL/flow cytometry, respectively. Ferroptosis markers (Fe2+, ROS, MDA, and GSH) and inflammatory cytokines were quantified using ELISA and commercial kits per manufacturers' protocols. The interaction of USP22 with ACSL4 was demonstrated through protein stability and co-immunoprecipitation (Co-IP) assays. Additionally, RNA immunoprecipitation (RIP) and mRNA stability assays were employed to elucidate the ELAVL1/USP22 interaction. RESULTS In HG-treated podocytes, USP22 silencing enhanced cell viability (P = 0.0018), repressed apoptosis (P = 0.0019), and reduced the release of inflammatory cytokines (IL-1β: P = 0.0002; TNF-α: P < 0.0001) and ferroptosis markers (Fe2+: P = 0.0002; ROS: P = 0.0005; MDA: P = 0.0017; GSH: P = 0.0086). Conversely, USP22 overexpression in HG-treated podocytes exhibited the opposite effects (P < 0.05). USP22 increased ACSL4 expression (P = 0.0012) in a deubiquitination-dependent manner. Notably, ACSL4 overexpression rescued USP22 depletion-mediated alterations on cell viability, apoptosis, inflammation, and ferroptosis (P < 0.05). Moreover, ELAVL1 stabilized USP22 mRNA through interaction (P = 0.0075). USP22 silencing alleviated DN progression and reduced inflammation cytokine secretion in a diabetic mouse model (P < 0.05). CONCLUSION ELAVL1-stabilized USP22 promotes DN progression by exacerbating podocyte injury and enhancing inflammatory responses and cell death through ACSL4 deubiquitination-dependent mechanisms.

Abstract This study evaluated the effects of human umbilical cord mesenchymal stem cell-derived exosomes (hUCMSC-exos) on renal function in naturally aging mice and explored underlying mechanisms. Twenty-four-month-old C57BL/6J mice were divided into a natural aging group (WT-AC, n = 10) and an hUCMSC-exos intervention group (WT-AEX, n = 10). Blood and kidney tissues were analyzed for biochemical markers, histological changes, and metabolomic profiles. hUCMSC-exos significantly reduced blood urea nitrogen, creatinine, and uric acid levels compared to the natural aging group (P < 0.01). Histological examination revealed reduced inflammatory cell infiltration, tubular degeneration, and interstitial fibrosis in the hUCMSC-exos group. Transmission electron microscopy demonstrated mitochondrial shrinkage, cristae rupture, and podocyte foot process effacement in the natural aging group, while the hUCMSC-exos group exhibited restored mitochondrial morphology, including intact cristae and reduced swelling. Aging markers (SA-β-Gal, p16INK4a, and γH2AX) were downregulated in the hUCMSC-exos group. Metabolomics identified 62 differential metabolites, with indoxyl sulfate as a potential biomarker for age-related renal injury. Enriched pathways included glutathione metabolism, glycerolipid metabolism, and aminoacyl-tRNA biosynthesis. hUCMSC-exos inhibited ferroptosis by reducing divalent iron ions and malondialdehyde levels, increasing the glutathione/oxidized glutathione ratio, and upregulating glutathione peroxidase 4 expression. These findings suggest that hUCMSC-exos improve renal function, reduce inflammation and fibrosis, and mitigate aging-related structural changes in naturally aging mice. The study highlights the protective role of hUCMSC-exos against renal aging through modulation of key metabolic pathways and ferroptosis inhibition, providing potential therapeutic targets for aging-related kidney injury.

Autophagy is a cellular process that degrades damaged cytoplasmic components and regulates cell death. The homeostasis of endothelial cells (ECs) is crucial for the preservation of glomerular structure and function in aging. Here, we investigated the precise mechanisms of endothelial autophagy in renal aging. The genetic deletion of Atg7 in the ECs of Atg7flox/flox;Tie2-Cre mice accelerated aging-related glomerulopathy and tubulointerstitial fibrosis. The EC-specific Atg7 deletion in aging mice induced the detachment of EC with the disruption of glomerular basement membrane (GBM) assembly and increased podocyte loss resulting in microalbuminuria. A Transwell co-culture system of ECs and kidney organoids showed that the iron and oxidative stress induce the disruption of the endothelial barrier and increase vascular permeability, which was accelerated by the inhibition of autophagy. This resulted in the leakage of iron through the endothelial barrier into kidney organoids and increased oxidative stress, which led to ferroptotic cell death. The ferritin accumulation was increased in the kidneys of the EC-specific Atg7-deficient aging mice and upregulated the NLRP3 inflammasome signaling pathway. The pharmacologic inhibition of ferroptosis with liproxstatin-1 recovered the disrupted endothelial barrier and reversed the decreased expression of GPX4, as well as NLRP3 and IL-1β, in endothelial autophagy-deficient aged mice, which attenuated aging-related renal injury including the apoptosis of renal cells, abnormal structures of GBM, and tubulointerstitial fibrosis. Our data showed that endothelial autophagy is essential for the maintenance of the endothelial barrier during renal aging and the impairment of endothelial autophagy accelerates renal senescence by ferroptosis and NLRP3 inflammasome signaling pathways. These processes may be attractive therapeutic targets to reduce cellular injury from renal aging.

BACKGROUND Diabetic nephropathy (DN) is one of the most serious complications of diabetes. Rhein has been reported to be effective in treating DN. This study aimed to investigate the role and mechanism of rhein in the treatment of DN. METHODS High glucose-induced (HG) podocyte injury model and streptozocin-induced (STZ) DN mouse model were constructed and intervened with rhein. Cell viability was detected by Cell Counting Kit-8 (CCK-8) assay. The reactive oxygen species (ROS) level was measured by flow cytometry. The expression of Ras-related C3 botulinum toxin substrate 1 (Rac1), NADPH Oxidase 1 (NOX1), and β-catenin were measured by quantitative real-time PCR (RT-qPCR). The contents of glutathione peroxidase 4 (GPX4), α-smooth muscle actin (α-SMA), Nephrin, and Podocin were characterized by immunofluorescence (IF) staining. Hematoxylin-eosin (HE) staining and Masson staining were employed to observe the renal morphological changes and tubulointerstitial fibrosis. The contents of α-SMA and Nephrin were detected by immunohistochemistry (IHC) staining. The kits were utilized to analyze various biochemical indicators. RESULTS Rhein inhibited the HG-induced accumulation of ROS, malondialdehyde (MDA), and Fe2+, and the expression of α-SMA, Transferrin Receptor 1 (TFR1), acyl-CoA synthetase long-chain family member 4 (ACSL4), Vimentin, Snail, and Desmin. Rhein inhibited the expression of Rac1 and its downstream targets NOX1 and β-catenin. Rac1 silencing (si-Rac1) inhibited the accumulation of MDA and Fe2+ and the expression of Rac1, NOX1, β-catenin, α-SMA, TFR1, and ACSL4. Rac1 overexpression (oe-Rac1) resulted in the inhibition of superoxide dismutase (SOD), glutathione (GSH), GPX4 synthesis, and down-regulation of Recombinant Solute Carrier Family 7, Member 11 (SLC7A11) and Nephrin expression in HG-treated podocytes. Rac1 Lentivirus (LV-Rac1) injection significantly promoted the accumulation of MDA and Fe2+ and increased the expression of RAC1, NOX1, β-catenin, TFR1, ACSL4, and α-SMA in DN mice. CONCLUSIONS Rhein inhibited ferroptosis and epithelial-mesenchymal transition (EMT) to attenuate DN by regulating the Rac1/NOX1/β-catenin axis.

Preeclampsia (PE) is a serious pregnancy complication characterized by elevated blood pressure and a major cause of maternal and perinatal morbidities, also known to increase the risk of chronic kidney disease. Mechanisms underlying PE-induced kidney injury remain unclear. Anti-angiotensin II type 1 receptor agonistic autoantibody (AT1-AA) is reported to participate in the pathogenesis of PE-induced kidney injury. Our previous study replicated the major features of PE in pregnant mice by administration of intravenous injection of AT1-AA and found that podocyte senescence plays a role in PE-induced kidney injury. Elevated levels of N-acetyl-β-D glucosaminidase (NAG) and kidney injury molecule-1 (KIM-1) in the urine of patients with PE have been reported, indicating renal tubular injury. In this study, we identified the role of renal proximal tubular epithelial cells (PTECs) in PE-induced kidney injury and the therapeutic value of empagliflozin, an anti-diabetic agent, in a murine model of AT1-AA-induced PE. In our study, higher tubular injury score (Control vs. PE: P<0.0001) show that PTECs are damaged in AT1-AA-induced PE. We identified ferroptosis as one of the cause of AT1-AA-induced PTEC injury by RNAseq, and confirmed the involvement of ferroptosis by detecting ferrous iron (Control vs. PE: P<0.0001), reduced glutathione (GSH) (Control vs. PE: P<0.0001) and lipid peroxidation (Control vs. PE: P<0.0001). Empagliflozin ameliorates AT1-AA-induced PTEC ferroptosis and injury in PE. Furthermore, we demonstrated that tazarotene-induced gene 1 is involved in AT1-AA-induced PTEC injury. These findings suggest that renal tubules are injured in PE and empagliflozin has therapeutic potential for PE-induced PTEC injury.

Ferroptosis is a non-apoptotic form of cell death, involved in chronic kidney diseases (CKD) and acute kidney injury (AKI), so far, the role of ferroptosis in focal segmental glomerulosclerosis (FSGS) remains largely unknown. We aimed to investigate the role of ferroptosis in FSGS, in this study, we found the reduced expression of GPX4 in podocytes, as well as tubular epithelial cells (TECs), from patients with FSGS. Treatment with ferrostatin-1 (Fer-1), a potent and selective ferroptosis inhibitor, significantly reduced proteinuria, prevented glomerulosclerosis, attenuated podocyte injury in ADR-induced FSGS murine model. As expected, ADR treatment caused downregulation of GPX4 in human podocytes, treatment with Fer-1 greatly blocked the downregulation of GPX4, restored the GSH level and attenuated cell death. Furthermore, Fer-1 treatment greatly delayed the development of tubulointerstitial fibrosis in ADR-induced FSGS murine model. Taken together, ferroptosis is involved in the pathogenesis of FSGS, targeting ferroptosis is a promising therapeutic option for patients with FSGS.

No abstract available

Aims: Diabetic nephropathy (DN) is characterized by microalbuminuria, mainly associated with pathological and morphological alterations of podocyte. New drug targeting podocyte injury is a promising approach for treating DN. The present study is aimed at developing new drug targeting podocyte injury for treating DN. Results: In this study, germacrone ameliorated kidney damage and inhibited podocyte apoptosis in a DN mouse model. Based on RNA-seq, mmu_mmu_circRNA_0000309, located in host gene vascular endothelial zinc finger 1 (Vezf1), showed a sharp decline in DN mice and a remarkable recovery in germacrone-challenged DN mice. mmu_circRNA_0000309 silence or miR-188-3p mimics abrogated the antiapoptosis and anti-injury effects of germacrone through aggravating mitochondria damage, and elevating reactive oxygen species and ferroptosis-related protein levels. Mechanistically, mmu_circRNA_0000309 competitively sponged miR-188-3p, and subsequently promoted glutathione peroxidase 4 (GPX4) expression, thereby inactivating ferroptosis-dependent mitochondrial damage and podocyte apoptosis. In addition, GPX4 overexpression neutralized mmu_circRNA_0000309 silence-mediated mitochondria damage and ferroptosis in germacrone-exposed MPC5 cells. Innovation: We describe the novel effect and mechanism of germacrone on treating DN, which is linked to ferroptosis for the first time. Conclusion: mmu_circRNA_0000309 silence mediates drug resistance to germacrone in DN mice. mmu_circRNA_0000309 sponges miR-188-3p, and subsequently upregulates GPX4 expression, inactivating ferroptosis-dependent mitochondrial function and podocyte apoptosis. Possibly germacrone-based treatment for DN can be further motivated by regulating mmu_circRNA_0000309/miR-188-3p/GPX4 signaling axis. Antioxid. Redox Signal. 36, 740–759.