Protective effect of Idelalisib on carbon tetrachloride‐induced liver fibrosis via microRNA‐124‐3P/phosphatidylinositol‐3‐hydroxykinase signalling pathway

Liver fibrosis is the repair process of abnormal connective tissue hyperplasia after liver damage caused by different causes. Inhibition of PI3K/Akt signalling pathway can reduce the deposition of extracellular matrix, inhibit the proliferation of hepatic stellate cells (HSCs), and promote its apoptosis to achieve the purpose of therapy. This study aimed to investigate the effect of Idelalisib (PI3K inhibitor) on carbon tetrachloride (CCl(4))‐induced liver fibrosis in mice. We used CCl(4)‐induced liver fibrosis mouse model in vivo and TGF‐β1‐stimulated HSCs to evaluate the antifibrosis activity of Idelalisib. In vivo, Idelalisib significantly alleviated CCl(4)‐induced liver damage, collagen deposition, and hydroxyproline accumulation in mice. Immunohistochemistry and Western blot results showed that Idelalisib could significantly inhibit the expressions of COL1 and α‐SMA in a concentration‐dependent manner. In cell experiments, Idelalisib significantly inhibited the expressions of COL1, SMA, and p‐Smad3 in TGF‐β‐induced HSCs, thereby inhibiting HSC activation. Flow cytometry and Western blot results showed that Idelalisib significantly promoted TGFβ‐induced apoptosis of HSCs after 48 h of administration, but had no significant effect after 24 h. Idelalisib promoted the apoptosis of activated HSCs by inhibiting the PI3K/Akt/FOXO3 signalling pathway. To further explore the mechanism by which Idelalisib inhibited PI3K, we predicted the miRNA targeting PI3K through the database and crossed it with the down‐regulated miRNA reported in liver fibrosis mice in the past five years. Finally, we identified miR‐124‐3p and miR‐143‐3p. We then demonstrated that Idelalisib significantly promoted miR‐124‐3p and miR‐142‐3p in vitro and in vivo. Dual‐luciferase report analysis showed that Idelalisib significantly inhibited luciferase activity but had no significant effect on the luc‐MUT transfection assay. Finally, we demonstrated that Idelalisib reversed the effects of miR‐124‐3p inhibitor on the PI3K/Akt/FOXO3 asterisk pathway and caspase‐3. Idelalisib has potential as a candidate drug for alleviating liver fibrosis.