Mild hypothermia alleviates ferroptosis in kidney ischemia-reperfusion injury via the glycolysis-lactate-HMGB1 lactylation axis.

BACKGROUND

Kidney ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, with ferroptosis being a key contributor. The role of mild hypothermia (MH) and its link to metabolic-epigenetic pathways like HMGB1 lactylation in ferroptosis remains unknown.

METHODS

Using a murine kidney IRI model and an in vitro OGD/R model in HK-2 cells, we assessed the effects of MH. Interventions included the ferroptosis inducer Erastin and the lactylation enhancer CTPB, HMGB1 knockdown, and the glycolysis promoter Rotenone. Renal function, histopathology, oxidative stress, iron metabolism, ferroptosis markers, glycolysis, HMGB1 lactylation, lipid peroxidation (C11-BODIY), and inflammatory cytokines (IL-1β, IL-6, TNF-α) were evaluated.

RESULTS

MH significantly preserved renal function, attenuated tubular injury, and reduced oxidative stress. It markedly inhibited ferroptosis, evidenced by decreased iron overload, lipid peroxidation, and restored expression of GPX4 and SLC7A11 while suppressing ACSL4. Mechanistically, MH suppressed glycolysis (reduced lactate, LDHA, PKM2, HK2) and subsequently inhibited HMGB1 lactylation and its cytoplasmic translocation. These protective effects were reversed by Erastin and CTPB. HMGB1 knockdown attenuated OGD/R-induced ferroptosis marker changes. Rotenone reversed MH-mediated suppression of lipid peroxidation and inflammatory cytokines. MH also reduced IRI-induced renal inflammatory cytokine expression in vivo.

CONCLUSION

MH protects against renal IRI by inhibiting ferroptosis, mediated through suppression of the glycolysis-lactate-HMGB1 lactylation axis. This reveals a novel mechanistic pathway for MH and suggests a potential therapeutic strategy.