[Quercetin induces hepatic stellate cell apoptosis by inhibiting the PI3K/Akt signaling pathway via upregulating miR-146]

OBJECTIVE

To investigate whether quercetin induces apoptosis of hepatic stellate cells by regulating miR-146 to inhibit the PI3K/Akt signaling pathway.

METHODS

Rat hepatic stellate cells (HSC-T6) were treated with TGF-β and different concentrations (40, 60 and 80 μmol/L) of quercetin, and the changes in cell proliferation and apoptosis were detected using CCK-8 assay and flow cytometry. RT-qPCR was used to detect the expression of miR-146 and mRNA expressions of α-SMA, collagenⅠ, TRAF6, PI3K and Akt in the treated cells, and the protein expressions of α-SMA, collagenⅠ, TRAF6, PI3K, Akt and p-Akt were detected using Western blotting. Immunofluorescence assay was used to detect the protein expression of α-SMA and collagenⅠ. The effects of transfection with miR-146 mimic and inhibitor on the protein expressions of the cells were also examined using Western blotting.

RESULTS

Treatment with quercetin dose- and time-dependently inhibited the proliferation of HSC-T6 cells and significantly increased the total cell apoptosis rate (P<0.01). TGF-β-stimulated HSC-T6 cells showed significantly increased mRNA and protein expression levels of α-SMA, collagenⅠ, TRAF6, PI3K and Akt (P<0.05), which were significantly down-regulated by quercetin treatment (P<0.05). Quercetin significantly upregulated the expression of miR-146 in HSC-T6 cells (P<0.01), Transfection of the cells with miR-146 mimic significantly decreased the mRNA and protein expression levels of α-SMA, collagen Ⅰ, TRAF6, PI3K and Akt (P<0.05), and miR- 146 inhibitor produced the opposite effects (P<0.05).

CONCLUSION

Quercetin inhibits proliferation and promotes apoptosis of HSCs by upregulating miR-146 to inhibit the PI3K/Akt signaling pathway.