Aortic carboxypeptidase-like protein, a WNT ligand, exacerbates nonalcoholic steatohepatitis

J Clin Invest. 2018 Apr 2;128(4):1581-1596. doi: 10.1172/JCI92863. Epub 2018 Mar 19.


Incidence of nonalcoholic steatohepatitis (NASH), which is considered a hepatic manifestation of metabolic syndrome, has been increasing worldwide with the rise in obesity; however, its pathological mechanism is poorly understood. Here, we demonstrate that the hepatic expression of aortic carboxypeptidase-like protein (ACLP), a glycosylated, secreted protein, increases in NASH in humans and mice. Furthermore, we elucidate that ACLP is a ligand, unrelated to WNT proteins, that activates the canonical WNT pathway and exacerbates NASH pathology. In the liver, ACLP is specifically expressed in hepatic stellate cells (HSCs). As fatty liver disease progresses, ACLP expression is enhanced via activation of STAT3 signaling by obesity-related factors in serum. ACLP specifically binds to frizzled-8 and low-density lipoprotein-related receptor 6 to form a ternary complex that activates canonical WNT signaling. Consequently, ACLP activates HSCs by inhibiting PPARγ signals. HSC-specific ACLP deficiency inhibits fibrosis progression in NASH by inhibiting canonical WNT signaling in HSCs. The present study elucidates the role of canonical WNT pathway activation by ACLP in NASH pathology, indicating that NASH can be treated by targeting ACLP-induced canonical WNT pathway activation in HSCs.

Keywords: Cell Biology; Fibrosis; Hepatitis; Hepatology; Obesity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Animals
  • Carboxypeptidases / metabolism*
  • Female
  • Hepatic Stellate Cells / enzymology*
  • Hepatic Stellate Cells / pathology
  • Humans
  • Liver / enzymology*
  • Liver / pathology
  • Male
  • Mice
  • Mice, Knockout
  • Middle Aged
  • Non-alcoholic Fatty Liver Disease / enzymology*
  • Non-alcoholic Fatty Liver Disease / pathology
  • Receptors, Cell Surface / metabolism
  • Receptors, G-Protein-Coupled / metabolism
  • Repressor Proteins / metabolism*
  • Wnt Proteins / metabolism
  • Wnt Signaling Pathway*


  • AEBP1 protein, human
  • Aebp1 protein, mouse
  • Fzd8 protein, human
  • Receptors, Cell Surface
  • Receptors, G-Protein-Coupled
  • Repressor Proteins
  • Wnt Proteins
  • frizzled 8 protein, mouse
  • Carboxypeptidases