Autophagy of OTUD5 destabilizes GPX4 to confer ferroptosis-dependent kidney injury.

Ferroptosis is an iron-dependent programmed cell death associated with severe kidney diseases, linked to decreased glutathione peroxidase 4 (GPX4). However, the spatial distribution of renal GPX4-mediated ferroptosis and the molecular events causing GPX4 reduction during ischemia-reperfusion (I/R) remain largely unknown. Using spatial transcriptomics, we identify that GPX4 is situated at the interface of the inner cortex and outer medulla, a hyperactive ferroptosis site post-I/R injury. We further discover OTU deubiquitinase 5 (OTUD5) as a GPX4-binding protein that confers ferroptosis resistance by stabilizing GPX4. During I/R, ferroptosis is induced by mTORC1-mediated autophagy, causing OTUD5 degradation and subsequent GPX4 decay. Functionally, OTUD5 deletion intensifies renal tubular cell ferroptosis and exacerbates acute kidney injury, while AAV-mediated OTUD5 delivery mitigates ferroptosis and promotes renal function recovery from I/R injury. Overall, this study highlights a new autophagy-dependent ferroptosis module: hypoxia/ischemia-induced OTUD5 autophagy triggers GPX4 degradation, offering a potential therapeutic avenue for I/R-related kidney diseases.

[Bioinformatics analysis and validation of key genes in transformation of idiopathic membranous nephropathy to end-stage renal disease and traditional Chinese medicines for prevention and treatment].

This study used bioinformatics analysis to screen out key genes involved in the transformation of idiopathic membranous nephropathy to end-stage renal disease and to predict targeted Chinese herbs and medicines and active ingredients with preventive and curative effects. The GSE108113 microarray of idiopathic membranous nephropathy and GSE37171 microarray of were downloaded from the comprehensive gene expression database, and 8 homozygous differentially expressed genes for the transformation of idiopathic membranous nephropathy into end-stage renal disease of were screened out by R software. GraphPad Prism was used to verify the expression of homozygous differentially expressed genes in GSE115857 microarray of idiopathic membranous nephropathy and GSE66494 microarray of chronic kidney disease, and 7 key genes(FOS, OGT, CLK1, TIA1, TTC14, CHORDC1, and ANKRD36B) were finally obtained. The Gene Ontology(GO) analysis was performed. There were 209 functions of encoded proteins, mainly involved in regulation of RNA splicing, cytoplasmic stress granule, poly(A) binding, etc. Thirteen traditional Chinese medicines with the effect of preventing the transformation of idiopathic membranous nephropathy to end-stage renal disease were screened out from Coremine Medical database, including Ginseng Radix et Rhizoma, Lycopi Herba, and Gardeniae Fructus, which were included in the Chinese Pharmacopoeia(2020 edition). The active ingredient quercetin mined from Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP) had ability to dock with the key gene FOS-encoded protein molecule, which provided targets and research ideas for the development of new traditional Chinese medicines.

Glutathione metabolism rewiring protects renal tubule cells against cisplatin-induced apoptosis and ferroptosis.

Renal proximal tubular cells are highly vulnerable to different types of assaults during filtration and reabsorption, leading to acute renal dysfunction and eventual chronic kidney diseases (CKD). The chemotherapeutic drug cisplatin elicits cytotoxicity causing renal tubular cell death, but its executing mechanisms of action are versatile and elusive. Here, we show that cisplatin induces renal tubular cell apoptosis and ferroptosis by disrupting glutathione (GSH) metabolism. Upon cisplatin treatment, GSH metabolism is impaired leading to GSH depletion as well as the execution of mitochondria-mediated apoptosis and lipid oxidation-related ferroptosis through activating IL6/JAK/STAT3 signaling. Inhibition of JAK/STAT3 signaling reversed cell apoptosis and ferroptosis in response to cisplatin induction. Using a cisplatin-induced acute kidney injury (CAKI) mouse model, we found that inhibition of JAK/STAT3 significantly mitigates cisplatin nephrotoxicity with a reduced level of serum BUN and creatinine as well as proximal tubular distortion. In addition, the GSH booster baicalein also reclaims cisplatin-induced renal tubular cell apoptosis and ferroptosis as well as the in vivo nephrotoxicity. In conclusion, cisplatin disrupts glutathione metabolism, leading to renal tubular cell apoptosis and ferroptosis. Rewiring glutathione metabolism represents a promising strategy for combating cisplatin nephrotoxicity.