Novel epigenetic biomarkers following ferroptosis and pyroptosis in a hypobaric hypoxia-induced renal injury model.

Abstract

BACKGROUND: Rapid hypobaric hypoxia exposure damages oxygen-sensitive organs like the kidneys. Ferroptosis and pyroptosis, oxygen-dependent cell death mechanisms, remain understudied in this context, as does the role of mitochondrial DNA (mtDNA) methylation. METHODS: We established a rat model of hypobaric hypoxia (6000 m/7000 m, 6 h/72 h). Kidney ferroptosis (Prussian blue staining, LPO/MDA/GSH assays, ACSL4/GPX4 expression) and pyroptosis (Caspase1/GSDMD activation) were analyzed. mt-cox1/2/3 methylation was assessed in renal mitochondrial DNA, cytoplasmic DNA, and serum cell-free DNA (cf mtDNA) via pyrosequencing. PCA identified biomarkers. RESULTS: Hypobaric hypoxia induced renal iron accumulation, lipid peroxidation, and tubular injury. Ferroptosis was mediated by ACSL4 upregulation and GPX4 suppression, while pyroptosis activated Caspase1/GSDMD. Mitochondrial damage and mtDNA leakage were observed via TEM. mt-cox3 pos2 hypermethylation in serum cell-free mtDNA distinctly distinguished hypoxia-exposed rats via PCA. CONCLUSION: Ferroptosis and pyroptosis synergize to drive hypobaric hypoxia-induced renal injury. mt-cox3 pos2 methylation in cell-free mtDNA emerges as a novel biomarker for renal pathogenesis.