Alcohol induces hepatocytes necroptosis through the LC3/RIPK1/RIPK3 pathway

Abstract

Excessive alcohol consumption leads to serious liver injury. Necroptosis is a programmed cell death form, which has been confirmed to be involved in alcoholic liver injury. However, the exact mechanism remains still unclear. In this study, we found that ethanol caused hepatocytes necroptosis by activating receptor-interacting serine/threonine-protein kinase 1 and 3 (RIPK1 and RIPK3). Meanwhile, autophagy was activated in ethanol-treated hepatocytes. Accumulative studies have demonstrated a possible link between autophagy and necroptosis. Microtubule-associated protein 1 light chain 3 (LC3), an autophagy marker protein, is essential for autophagosome biogenesis/maturation. But little attention has been paid to its functional role. In this study, we explored whether LC3 was involved in ethanol-induced necroptosis. The data showed that LC3 interacted with RIPK1 and RIPK3 in ethanol-treated AML12 cells and mice liver by co-immunoprecipitation (co-IP) and colocalization assay. Ethanol-induced necrosome formation and subsequent necroptosis were alleviated in hepatocytes by knockdown of LC3 or autophagy inhibitor 3-methyladenine (3-MA). These results demonstrated that LC3 accumulation facilitated the formation of necrosome by LC3-RIPK1 and LC3-RIPK3 interactions, eventually caused hepatocytes necroptosis after acute ethanol exposure. Our current research could potentially offer a new understanding of the intricate mechanisms involved in the development of acute alcoholic liver injury.

Keywords: Alcohol; LC3; Liver; Necroptosis; RIPK1; RIPK3.