Autophagy related 14 protects against liver injury by inhibiting multiple cell death pathways

Abstract

Background: Autophagy is critical for cellular homeostasis. Autophagy related 14 (ATG14) is a key regulator of autophagy initiation; however, its role in hepatocyte survival remains poorly understood. This study aimed to investigate the hepatocyte-specific function of ATG14 in vivo. Methods: We generated Atg14 hepatocyte-specific knockout (HepKO) mice using adeno-associated virus to deliver thyroxine-binding globulin gene promoter-driven Cre into Atg14 floxed mice at an adult age and fed control and knockout mice with either normal chow or a Western diet. Blood and tissue samples were collected for biochemical and histological analyses. Results: Atg14 HepKO mice develop severe hepatomegaly under normal dietary conditions. ATG14 deficiency leads to hepatic injury, inflammation and fibrosis. Multiple forms of cell death, including apoptosis and pyroptosis, increase significantly. When challenged with a Western diet for 4 weeks, Atg14 HepKO mice exhibit exacerbated hepatic injury, inflammation and fibrosis despite no significant lipid droplet accumulation in the liver. Transcriptomic analysis reveals upregulation of several cell death pathways, including pyroptosis, apoptosis and necroptosis. Further biochemical and microscopic analyses validate the induction of multiple cell death pathways. In addition, NLR family pyrin domain containing 3 inflammasome-mediated pyroptosis is significantly elevated in Atg14 HepKO mouse livers and ATG14-deficient hepatocytes. Conclusion: Our data suggest that ATG14 is required for maintaining hepatocyte identity, survival and function and that hepatic ATG14 deficiency may lead to hepatomegaly, tissue injury, inflammation and fibrosis.