Hepatic Sel1L-Hrd1 ER-associated degradation deficiency leads to intrahepatic cholestasis in mice

ABSTRACT: The liver is the central organ critically regulating the balance of the metabolically potent yet toxic bile acids in the body. While genomic association studies have pointed to hepatic Sel1L – a critical component of mammalian Hrd1 ER-associated degradation (ERAD) machinery – as an influencer of serum bile acid levels, physiological relevance and mechanistic insights of ERAD in bile homeostasis remain unexplored. Using hepatocyte-specific Sel1L-deficient mouse models, we report that hepatic Sel1L-Hrd1 ERAD critically manages bile homeostasis in the body. Mice with hepatocyte-specific Sel1L developed intrahepatic cholestasis, with significant overload of bile acids in the liver and circulation under basal condition, and were hypersensitive to dietary bile acid challenge. By contrast, biliary bile acid and phosphatidylcholine levels were reduced, pointing to an export defect from hepatocytes. Unbiased proteomics analysis followed by biochemical assays revealed significant accumulation of the bile-stabilizing phosphatidylcholine exporter ATP-binding cassette 4 (Abcb4) in the ER of Sel1L-deficient livers, a gene associated with Progressive Familial Intrahepatic Cholestasis type III. Indeed, Abcb4 was a substrate of Sel1L-Hrd1 ERAD. Hence, hepatic Sel1L-Hrd1 ERAD maintains bile equilibrium via quality control of Abcb4 maturation in the ER.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Liver

SUBMITTER: Asmita Bhattacharya  

LAB HEAD: Ling Qi

PROVIDER: PXD035243 | Pride | 2023-03-11

REPOSITORIES: Pride