Deficient Chaperone-Mediated Autophagy in Macrophage Aggravates Inflammation of Nonalcoholic Steatohepatitis by Targeting Nup85

Background: NASH, a more advanced subtype of nonalcoholic fatty liver disease (NAFLD), can lead to cirrhosis and hepatocellular carcinoma. Macrophage is regarded to play critical roles in initiating and maintaining liver inflammation and fibrosis of NASH. Macrophage chaperone-mediated autophagy (CMA) affects its lipid metabolism and inflammasome activation. However, the role of macrophage CMA in NASH remains unclear.Methods: Western-Blot, RT-qPCR and FACS technologies were employed to detect CMA function of liver macrophages. By constructing myeloid-specific CMA deficiency mice, we evaluated the effects of deficient CMA of macrophages on monocyte recruitment, liver injury, steatosis and fibrosis in NASH mice. ITRAQ-labelling MS/MS were used to screen the substrates of CMA in macrophages and their mutual interaction, the association between CMA and its substrate and were examined by immunoprecipitation, western-blot and RT-qPCR.Findings: Impaired CMA function in hepatic macrophages was a typical hallmark in murine NASH models. Monocyte-derived macrophages (MDM) were the dominant macrophage population in NASH, and CMA function in MDM was impaired. CMA dysfunction aggravated liver-targeted recruitment of monocyte and promoted steatosis, fibrosis and disease progression of NASH. Mechanistically, Nup85 could serve as a substrate of CMA, whose protein degradation was inhibited in macrophages with deficient CMA. Inhibition of Nup85 attenuated CMA deficiency-mediated monocyte recruitment and steatosis in NASH mice.Interpretation: Hepatic macrophages, especially MDM, CMA function was impaired in NASH, which increased Nup85-mediated monocyte recruitment, promoting liver inflammation and disease progression of NASH. Our study revealed a new mechanism that Nup85 was a CMA substrate, thus providing a new insight into the role of CMA-mediated monocyte recruitment in the progression of NASH.Funding Information: The study was funded by National Natural Science Foundation of China (No. 81820108005, 81870398, 81900502) and Key Research and Development Program of Shaanxi (No. 2021ZDLSF02-07). And we thank the Figdraw (www.figdraw.com) for providing graphic elements in creating the graphical abstract.Declaration of Interests: The authors have declared that no competing interest exists.Ethics Approval Statement: Animal experiments were approved by the Ethics Committee of the Air Fourth Military Medical University (IACOC-20200757).