Hypothermic machine perfusion attenuates DCD liver ischemia reperfusion injury via the YAP1/P53-mediated micromitophagy pathway.

Donation after circulatory death (DCD) livers are subjected to severe ischemia-reperfusion injury (IRI) during transplantation. Hypothermic machine perfusion (HMP) offers superior mitochondria protection compared with conventional cold storage (CS), yet the underlying molecular mechanisms remain incompletely understood. In this study, we investigated the mechanistic basis of HMP protection using a rat DCD liver model combined with an in vitro hypoxia/reoxygenation model in human umbilical vein endothelial cells (HUVECs). Rats were subjected to 30 min of warm ischemia followed by CS, HMP and normothermic machine perfusion (NMP). HMP significantly ameliorated liver dysfunction, histopathological damage, oxidative stress and inflammation compared with CS. Mechanistically, HMP upregulated yes-associated protein 1 (YAP1) expression and promoted P53 nuclear translocation, thereby enhancing the expression of microautophagy-related proteins including mitochondria-eating protein (MIEAP), BCL2 interacting protein 3 (BNIP3) and BNIP3-like (BNIP3L), and facilitating the formation of mitochondrial-derived vesicles (MDVs). These effects were abrogated by the YAP1 inhibitor verteporfin in vivo and by YAP1 knockdown or MIEAP silencing in vitro. Collectively, our findings demonstrate that HMP reduced oxidative damage and inflammation of DCD liver through YAP1/P53-mediated micromitophagy.