Dihydromyricetin ameliorates liver fibrosis via inhibition of hepatic stellate cells by inducing autophagy and natural killer cell-mediated killing effect

Abstract

Background This study investigated the mechanisms underlying the preventive effect of dihydromyricetin (DHM) against liver fibrosis involving hepatic stellate cells (HSCs) and hepatic natural killer (NK) cells. Methods A carbon tetrachloride (CCl4)-induced liver fibrosis model was established in C57BL/6 mice to study the antifibrotic effect of DHM based on serum biochemical parameters, histological and immunofluorescence stainings, and the expression of several fibrosis-related markers. Based on the immunoregulatory role of DHM, the effect of DHM on NK cell activation ex vivo was evaluated by flow cytometry. Then, we investigated whether DHM-induced autophagy was involved in HSCs inactivation using enzyme-linked immunosorbent assays, transmission electron microscopy, and western blot analysis. Thereafter, the role of DHM in NK cell-mediated killing was studied by in vitro coculture of NK cells and HSCs, with subsequent analysis by flow cytometry. Finally, the mechanism by which DHM regulates NK cells was studied by western blot analysis. Results DHM ameliorated liver fibrosis in C57BL/6 mice, as characterized by decreased serum alanine transaminase and aspartate transaminase levels, decreased expressions of collagen I alpha 1 (CoL-1α1), collagen I alpha 2 (CoL-1α2), tissue inhibitor of metalloproteinases 1 (TIMP-1), α-smooth muscle actin (α-SMA) and desmin, as well as increased expression of matrix metalloproteinase 1 (MMP1). Interestingly, HSCs activation was significantly inhibited by DHM in vivo and in vitro. As expected, DHM also upregulated autophagy-related indicators in liver from CCl4-treated mice. DHM also prevented TGF-β1-induced activation of HSCs in vitro by initiating autophagic flux. In contrast, the autophagy inhibitor 3-methyladenine markedly abolished the antifibrotic effect of DHM. Surprisingly, the frequency of activated intrahepatic NK cells was significantly elevated by DHM ex vivo. Furthermore, DHM enhanced NK cell-mediated killing of HSCs by increasing IFN-γ expression, which was abolished by an anti-IFN-γ neutralizing antibody. Mechanistically, DHM-induced IFN-γ expression was through AhR-NF-κB/STAT3 pathway in NK cells. Conclusion These results demonstrated that DHM can ameliorate the progression of liver fibrosis and inhibition of HSCs activation by inducing autophagy and enhancing NK cell-mediated killing through the AhR-NF-κB/STAT3-IFN-γ signaling pathway, providing new insights into the preventive role of DHM in liver fibrosis.

Dihydromyricetin Reverses Thioacetamide-Induced Liver Fibrosis Through Inhibiting NF-κB-Mediated Inflammation and TGF-β1-Regulated of PI3K/Akt Signaling Pathway

“…α-SMA is a marker of HSCs activation, and TGF-β1 is generally considered to be the main hepatic fibrosis-promoting cytokine, and many factors leading to liver disease are related to TGF-β1 in varying degrees ( Dewidar et al, 2015 ). In this study, immunofluorescence staining demonstrated that the positive expression of a-SMA and TGF-β1 were significantly increased in liver tissue by TAA-induced, which was consistent with previous studies ( Mi et al, 2019 ; Zhou et al, 2021 ). The increase in α-SMA and TGF-β1 in turn induced the synthesis and secretion of ECM by HSC, thus aggravating liver fibrosis ( Crosas-Molist et al, 2015 ).…”

“…Yi Zeng et al demonstrated a protective effect of dihydromyricetin in improving non-alcoholic steatohepatitis ( Zeng et al, 2020 ). Xi Zhou et al demonstrated that dihydromyricetin attenuated carbon tetrachloride-induced liver injury by modulating autophagy and inhibiting the activation of hepatic stellate cells ( Zhou et al, 2021 ). Ping Qiu et al also demonstrated the protective effect of dihydromyricetin against ethanol-induced liver injury ( Qiu et al, 2017 ).…”

Dihydromyricetin-Encapsulated Liposomes Inhibit Exhaustive Exercise-Induced Liver Inflammation by Orchestrating M1/M2 Macrophage Polarization

“…Male C57BL/6J mice were fed in a condition as previously reported (Zhou et al, 2021). The experimental procedure of each group was illustrated in Figure 1A.…”

“…Protein expression was investigated by western blot analysis as in previous methods (Zhou et al, 2021). The primary antibodies were used to study the protein expression of sirtuins-3 (SIRT3, 1: 1000 dilution; Cell Signaling Technology, #2627S), hypoxiainducible factor-1α (HIF-1α, 1:300 dilution; Proteintech,…”

Dihydromyricetin Alleviates Pulmonary Fibrosis by Regulating Abnormal Fibroblasts Through the STAT3/p-STAT3/GLUT1 Signaling Pathway

“…Dihydromyricetin (DHM, the structure of which is shown in Figure 1 ), a natural flavonoid extracted from vine tea and other Ampelopsis species, has anti-inflammatory and antioxidant effects and has been proven to inhibit liver fibrosis and diabetic nephropathy ( Liu et al, 2019 ; Zhou et al, 2021 ). However, its effects on pulmonary fibrosis have not been determined.…”