Steatotic liver-derived extracellular vesicles deliver ACSL4 to potentiate hepatic ischemia-reperfusion injury by orchestrating a ferroptosis-mitochondrial apoptosis cascade.

Steatotic liver grafts exhibit heightened susceptibility to hepatic ischemia-reperfusion injury (HIRI), contributing to poor outcomes in liver transplantation; however, the underling mechanisms remain incompletely defined. Here, we demonstrate that extracellular vesicles derived from steatotic livers (HFD-EVs) exacerbate HIRI by delivering acyl-CoA synthetase long-chain family member 4 (ACSL4) to hepatocytes, thereby triggering a ferroptosis-mitochondrial apoptosis cascade. Proteomic profiling revealed that HFD-EVs are enriched with ACSL4 and other pro-ferroptotic mediators, but deficient in mitochondrial oxidative phosphorylation components. In a murine model, administration of HFD-EVs to lean mice prior to ischemia-reperfusion significantly aggravated liver injury, apoptosis, and inflammatory responses compared to EVs from healthy livers. In vitro, HFD-EVs were internalized by hepatocytes, leading to ACSL4 up-regulation, GPX4 suppression, and subsequent iron-dependent lipid peroxidation. This ferroptotic stress induced mitochondrial calcium overload, permeability transition pore opening, membrane depolarization, and ultrastructural damage, culminating in cytochrome c release and apoptotic cell death. Critically, inhibition of ferroptosis with Ferrostatin-1 abolished ACSL4 induction, restored mitochondrial integrity, and rescued cell viability, confirming the central role of ferroptosis in HFD-EVs-induced injury. Our study unveils a previously unrecognized mechanism by which HFD-EVs transmit ACSL4 to initiate ferroptosis and mitochondrial dysfunction in recipient hepatocytes, providing a mechanistic basis for the vulnerability of steatotic grafts to HIRI. These findings highlight HFD-EVs and the ACSL4-ferroptosis axis as promising therapeutic targets to improve the quality of fatty liver grafts in transplantation.