Astilbin alleviates hepatic fibrosis through PXR-PINK1/Parkin pathway: A new strategy by regulating hepatic stellate cells-macrophage crosstalk

Abstract

Background: Astilbin (ATB), a natural dihydroflavonol compound, exists in many plants, processed and functional foods. ATB has multiple pharmacological effects, such as antioxidant, lipid-lowering, and hepatoprotective. However, its anti-hepatic fibrosis and mechanisms remain unclearly elucidated.

Purpose: This study explored the effect of ATB against the hepatic fibrosis and its regulation of hepatic microenvironment by regulating hepatic stellate cells-macrophage crosstalk.

Method: Thioacetamide (TAA) was intraperitoneal injected to establish hepatic fibrosis mice, and treated with ATB or curcumin by gavage, respectively. Hepatic stellate cells (HSCs) were stimulated with TGF-β or conditioned medium (CM) from LPS-induced THP-1, then cultured with ATB, PXR agonist or antagonist.

Results: In TAA-induced mice, ATB improved histopathological changes, serum transaminases increase; alleviated extracellular matrix (ECM) deposition, epithelial-mesenchymal transformation (EMT), inflammatory infiltration, PTEN induced kinase 1 (PINK1)/Parkin-mediated mitophagy and activated pregnane X receptor (PXR) expression. In vitro, ATB significantly reduced ECM, inflammatory cytokines release, mitophagy, EMT, and activated PXR expression. ATB could increase PXR and decrease PINK1/Parkin, functioning as a PXR agonist. PXR deficiency in LX-2 could degrade the regulation of ATB on ECM, inflammation, EMT, and mitophagy. CM from LPS-induced THP-1 activated LX-2 and resulted in PXR decreasing, while ATB could regulate the crosstalk between HSCs and macrophages. Deficiency of PXR, whether in LX-2 or in macrophages, all weakened the inhibitory effect of ATB on α-SMA, EMT, inflammatory cytokines, and PINK1/Parkin signaling.

Conclusion: ATB ameliorated hepatic fibrosis by inhibiting HSCs activation, inflammation and EMT through PXR-mediated PINK1/Parkin signaling. Especially, ATB targeted the hepatic microenvironment between hepatic stellate cells and macrophages, which might be a promising strategy for the treatment of hepatic fibrosis.

Keywords: Astilbin; Hepatic fibrosis; Hepatic microenvironment; PXR.