C-X-C Motif Chemokine 10 Impairs Autophagy and Autolysosome Formation in Non-alcoholic Steatohepatitis

Abstract

and steatohepatitis development in mice. Autophagic flux impairment was rectified by CXCL10 inhibition using anti-CXCL10 mAb in AML-12 and HepG2 liver cell lines and primary hepatocytes as evidenced by the attenuated accumulation of p62/SQSTM1 and LC3-II proteins and increased autophagic protein degradation. Impaired autophagic flux was significantly restored by CXCL10 knockout or anti-CXCL10 mAb in mice. Bafilomycin A1, an inhibitor of autolysosome formation, abolished the rectifying effect of anti-CXCL10 mAb or CXCL10 knockdown in AML-12 and primary hepatocytes, indicating CXCL10 impaired late-stage autophagy in NAFLD. Anti-CXCL10 mAb treatment also increased the fusion of LC3-positive autophagosomes with lysosomes in HepG2 cells challenged with palmitic acid, suggesting that CXCL10 ablation restored autolysosome formation. Consistently, the number of autolysosomes was significantly increased by CXCL10 knockout in mice as shown by electron microscopy. In conclusion, upregulated CXCL10 in steatohepatitis impairs autophagic flux by reducing autolysosome formation, thereby inhibiting autophagic protein degradation and the accumulation of ubiquitinated proteins, leading to the development of steatohepatitis.