The Protective Role of the IRE1α/XBP1 Signaling Cascade in Autophagy During Ischemic Stress and Acute Kidney Injury.

Abstract

Acute kidney injury (AKI) is a common and serious complication resulting from ischemia and hypoxia, leading to significant morbidity and mortality. Autophagy, a cellular process for degrading damaged components, plays a crucial role in kidney protection. The unfolded protein response (UPR) pathway, particularly the IRE1α/XBP1 signaling cascade, is implicated in regulating autophagy during renal stress. To elucidate the role of the IRE1α/XBP1 pathway in autophagy during hypoxia/reoxygenation (H/R) and ischemia/reperfusion (I/R) injury, renal tubular epithelial cells (TECs) were subjected to H/R conditions, and I/R injury was induced in mice. The expression of autophagy-related and ER stress markers (IRE1α, XBP1, GRP78, Beclin1, LC3I/II, and P62) was assessed using immunoblotting and immunofluorescence. Additionally, the impacts of IRE1α overexpression and pharmacological agents, IXA6 (IRE1α agonist) and STF083010 (IRE1α inhibitor), were evaluated on autophagy regulation. H/R injury significantly increased mitochondrial damage and the formation of autophagic vesicles in TECs. Key markers of autophagy were elevated in response to H/R and I/R injury, with activation of the IRE1α/XBP1 pathway enhancing autophagic processes. IXA6 treatment improved renal function and reduced injury in I/R models, while STF083010 exacerbated kidney damage. The IRE1α/XBP1 pathway is a critical regulator of autophagy in renal TECs during ischemic stress, suggesting that pharmacological modulation of this pathway may offer therapeutic avenues for preventing or mitigating AKI. Enhanced understanding of these mechanisms may lead to novel strategies for kidney disease management.