N-n-Butyl haloperidol iodide ameliorates liver fibrosis and hepatic stellate cell activation in mice

N -n-Butyl haloperidol iodide (F 2 ) is a novel compound that has antiproliferative and antifibrogenic activities. In this study we investigated the therapeutic potential of F 2 against liver fibrosis in mice and the underlying mechanisms. Two widely used mouse models of fibrosis was established in mice by injection of either carbon tetrachloride (CCl 4 ) or thioacetamide (TAA). The mice received F 2 (0.75, 1.5 or 3 mg·kg −1 ·d −1 , ip) for 4 weeks of fibrosis induction. We showed that F 2 administration dose-dependently ameliorated CCl 4 - or TAA-induced liver fibrosis, evidenced by significant decreases in collagen deposition and c-Jun, TGF-β receptor II (TGFBR2), α-smooth muscle actin (α-SMA), and collagen I expression in the liver. In transforming growth factor beta 1 (TGF-β1)-stimulated LX-2 cells (a human hepatic stellate cell line) and primary mouse hepatic stellate cells, treatment with F 2 (0.1, 1, 10 μM) concentration-dependently inhibited the expression of α-SMA, and collagen I. In LX-2 cells, F 2 inhibited TGF-β/Smad signaling through reducing the levels of TGFBR2; pretreatment with LY2109761 (TGF-β signaling inhibitor) or SP600125 (c-Jun signaling inhibitor) markedly inhibited TGF-β1-induced induction of α-SMA and collagen I. Knockdown of c-Jun decreased TGF-β signaling genes, including TGFBR2 levels. We revealed that c-Jun was bound to the TGFBR2 promoter, whereas F 2 suppressed the binding of c-Jun to the TGFBR2 promoter to restrain TGF-β signaling and inhibit α-SMA and collagen I upregulation. In conclusion, the therapeutic benefit of F 2 against liver fibrosis results from inhibition of c-Jun expression to reduce TGFBR2 and concomitant reduction of the responsiveness of hepatic stellate cells to TGF-β1. F 2 may thus be a potentially new effective pharmacotherapy for human liver fibrosis.