Mechanism of annexin A1/N-formylpeptide receptor regulation of macrophage function to inhibit hepatic stellate cell activation through Wnt/β-catenin pathway

Background: Hepatic fibrosis is a common pathological process of chronic liver diseases with various causes, which can progress to cirrhosis.

Aim: To evaluate the effect and mechanism of action annexin (Anx)A1 in liver fibrosis and how this could be targeted therapeutically.

Methods: CCl₄ (20%) and active N-terminal peptide of AnxA1 (Ac2-26) and N-formylpeptide receptor antagonist N-Boc-Phe-Leu-Phe-Leu-Phe (Boc2) were injected intraperitoneally to induce liver fibrosis in eight wild-type mice/Anxa1 knockout mice, and to detect expression of inflammatory factors, Collagen deposition, and the role of the Wnt/β-catenin pathway in hepatic fibrosis.

Results: Compared with the control group, AnxA1, transforming growth factor (TGF)-β1, interleukin (IL)-1β and IL-6 expression in the liver of mice with hepatic fibrosis induced by CCl₄ was significantly increased, which promoted Collagen deposition and expression of α-smooth muscle actin (α-SMA), Collagen type I and connective tissue growth factor (CTGF), and increased progressively with time. CCl₄ induced an increase in TGF-β1, IL-1β and IL-6 in liver tissue of AnxA1 knockout mice, and the degree of liver inflammation and fibrosis and expression of α-SMA, Collagen I and CTGF were significantly increased compared with in wild-type mice. After treatment with Ac2-26, expression of liver inflammatory factors, degree of Collagen deposition and expression of a-SMA, Collagen I and CTGF were decreased compared with before treatment. Boc2 inhibited the anti-inflammatory and antifibrotic effects of Ac2-26. AnxA1 downregulated expression of the Wnt/β-catenin pathway in CCl₄-induced hepatic fibrosis. In vitro, lipopolysaccharide (LPS) induced hepatocyte and hepatic stellate cell (HSC) expression of AnxA1. Ac2-26 inhibited LPS-induced RAW264.7 cell activation and HSC proliferation, decreased expression of α-SMA, Collagen I and CTGF in HSCs, and inhibited expression of the Wnt/β-catenin pathway after HSC activation. These therapeutic effects were inhibited by Boc2.

Conclusion: AnxA1 inhibited liver fibrosis in mice, and its mechanism may be related to inhibition of HSC Wnt/β-catenin pathway activation by targeting formylpeptide receptors to regulate macrophage function.

Active N-terminal peptide of annexin A1; Annexin A1; Hepatic stellate cell; Liver fibrosis; Macrophage; Wnt/β-catenin.