GLS2 Promotes Early Ferroptosis Followed by Apoptosis and p53 Signaling in Renal Ischemia-Reperfusion Injury.

Abstract

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury (AKI), particularly in the settings of kidney transplantation and perioperative care. In IRI-induced AKI, ferroptosis, an iron-dependent, lipid peroxidation-driven form of regulated cell death, occurs early in proximal tubular epithelial cells; however, the precise molecular mechanisms underlying ferroptosis, its crosstalk with other forms of regulated cell death, and its clinical relevance remain incompletely understood. We previously identified glutaminase 2 (GLS2) as a key regulator of ferroptosis via α-ketoglutarate (αKG). Because GLS2 is expressed in renal tubular cells, we investigated the role of the GLS2-αKG-ferroptosis axis using Gls2 knockout (KO) mice and an in vitro hypoxia-reoxygenation model mimicking renal IRI. Compared with wild-type (WT) mice, KO mice showed markedly attenuated tubular injury, accompanied by reduced mitochondrial shrinkage and decreased chromatin condensation in tubular cell nuclei. At 12 h post-IRI, ferroptosis-associated gene expression and GLS2-αKG-driven lipid peroxidation were significantly reduced in KO mice. At 24 h post-IRI, p53 and apoptosis-related gene expression, as well as caspase-3 cleavage, were also reduced. Moreover, intraperitoneal administration of a ferroptosis inhibitor, as well as local glutaminase inhibition via glutaminase inhibitor-impregnated surgical gauze applied to the kidney during ischemia, attenuated ferroptosis, subsequent apoptosis, and tubular injury in vivo in WT mice. To assess the clinical relevance of these findings, we analyzed publicly available Gene Expression Omnibus (GEO) datasets and found increased PTGS2 and GLS2 expression in human kidneys following IRI. These findings suggest that targeting the GLS2-ferroptosis axis represents a promising therapeutic strategy for ischemic AKI.