PERK suppression induces susceptibility to ferroptosis in lupus nephritis

Systemic Lupus Erythematosus (SLE) is an autoimmune disease, and the most common and serious complications in children is lupus nephritis (LN). Recent studies have identified ferroptosis as a pathological process present in both LN patients and mouse models of LN. However, the specific molecular mechanisms regulating ferroptosis in LN remain largely unexplored. Protein kinase RNA-like endoplasmic reticulum kinase (PERK) is a transmembrane protein involved in maintaining cellular homeostasis and promoting cell survival, has not been fully characterized in the context of LN. Our experimental findings have demonstrated that ferroptosis markers are significantly upregulated in LN patients and lupus mouse models. These changes include increased Fe²⁺ levels, decreased glutathione (GSH) content, and elevated mRNA expression of ferroptosis-associated genes. Interestingly, PERK and Solute Carrier Family 7 Member 11(SLC7A11, xCT) mRNA levels were markedly reduced in both LN patients and lupus mice compared to controls. Moreover, PERK expression showed a positive correlation with GSH levels, suggesting a potential protective role. Functional studies further revealed that PERK inhibition exacerbates renal injury and ferroptosis while reducing GSH content. In vitro experiments using HK-2 cells demonstrated that the ferroptosis inhibitor Fer-1 could restore GSH levels and counteract ferroptosis under PERK knockdown conditions. Mechanistically, PERK positively regulates the transcription of SLC7A11 via ATF4, highlighting its role in maintaining cellular redox balance. In conclusion, low PERK expression aggravate lupus nephritis by inhibiting SLC7A11 transcription via ATF4 and reducing GSH synthesis. These findings provide new directions and potential therapeutic targets for the role of PERK in the pathogenesis of LN.