Abstract

Renal ischemia-reperfusion injury (IRI) is a major cause of acute kidney injury, involving complex mechanisms of metabolic dysregulation and immune inflammation. This study investigated the role and molecular mechanism of acyl-CoA thioesterase 8 (ACOT8) in IRI by integrating multi-omics data with multi-level experimental validation. A pQTL-based Mendelian randomization analysis identified 456 genes with putative causal associations with AKI. Integrated analysis of multiple transcriptomic datasets, combined with machine learning algorithms (LASSO and SVM-RFE), identified four core candidate genes. Among them, ACOT8 was highly expressed specifically in renal tubular epithelial cells and showed a significant positive correlation with M1 macrophage infiltration. In vivo and in vitro experiments confirmed that ACOT8 was upregulated during IRI. Single-cell RNA sequencing and lipidomics revealed suppressed mitochondrial oxidative metabolism and significant lipid accumulation, particularly palmitate, in injured proximal tubules. Mechanistically, ACOT8 was found to modulate palmitate levels in tubular epithelial cells, thereby altering the local lipid milieu. This palmitate subsequently activated the cGAS-STING signaling pathway in macrophages, promoting their polarization toward a pro-inflammatory M1 phenotype and exacerbating the inflammatory response. Using an AAV9 vector with a kidney-specific promoter to knock down ACOT8 in tubular epithelial cells in a mouse model, we demonstrated that inhibiting ACOT8 significantly attenuated renal palmitate accumulation, reduced M1 macrophage infiltration, lowered serum pro-inflammatory cytokine levels, and improved renal function. In conclusion, this study demonstrates that ACOT8-mediated tubular palmitate accumulation promotes macrophage M1 polarization via the cGAS-STING pathway, thereby contributing to renal ischemia-reperfusion injury. ACOT8 represents a potential therapeutic target for ischemic kidney injury.