Jaceosidin attenuates the progression of hepatic fibrosis by inhibiting the VGLL3/HMGB1/TLR4 signaling pathway

Abstract

Background: Jaceosidin (JA) is a natural flavone extracted from Artemisia that is used as a food and traditional medicinal herb. It has been reported to possess numerous biological activities. However, the regulatory mechanisms underlying amelioration of hepatic fibrosis remain unclear.

Hypothesis/purpose: We hypothesized that jaceosidin acid (JA) modulates hepatic fibrosis and inflammation.

Methods: Thioacetamide (TAA) was used to establish an HF mouse model. In vitro, mouse primary hepatocytes and HSC-T6 cells were induced by TGF-β, whereas mouse peritoneal macrophages received a treatment lipopolysaccharide (LPS)/ATP.

Results: JA decreased serum transaminase levels and improved hepatic histological pathology in TAA-treated mice stimulated by TAA. Moreover, the expression of pro-fibrogenic biomarkers associated with the activation of liver stellate cells was downregulated by JA. Likewise, JA down-regulated the expression of vestigial-like family member 3 (VGLL3), high mobility group protein B1 (HMGB1), toll-like receptors 4 (TLR4), and nucleotide-binding domain-(NOD-) like receptor protein 3 (NLRP3), thereby inhibiting the inflammatory response and inhibiting the release of mature-IL-1β in TAA-stimulated mice. Additionally, JA suppressed HMGB1 release and NLRP3/ASC inflammasome activation in LPS/ATP-stimulated murine peritoneal macrophages. JA decreases the expression of pro-fibrogenic biomarkers related to liver stellate cell activation and inhibits inflammasome activation in mouse primary hepatocytes. It also down-regulated α-SMA and VGLL3 expressions and also suppressed inflammasome activation in HSC-T6 cells. VGLL3 and α-SMA expression levels were decreased in TGF-β-stimulated HSC-T6 cells following Vgll3 knockdown. In addition, the expression levels of NLRP3 and cleaved-caspase-1 were decreased in Vgll3-silenced HSC-T6 cells. JA enhanced the inhibitory effects on Vgll3-silenced HSC-T6 cells. Finally, Vgll3 overexpression in HSC-T6 cells affected the expression levels of α-SMA, NLRP3, and cleaved-caspase-1.

Conclusion: JA effectively modulates hepatic fibrosis by suppressing fibrogenesis and inflammation via the VGLL3/HMGB1/TLR4 axis. Therefore, JA may be a candidate therapeutic agent for the management of hepatic fibrosis. Understanding the mechanism of action of JA is a novel approach to hepatic fibrosis therapy.

Keywords: HMGB1; Hepatic fibrosis; Jaceosidin; TLR4; VGLL3.