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

N-n-Butyl haloperidol iodide (F) is a novel compound that has antiproliferative and antifibrogenic activities. In this study we investigated the therapeutic potential of F 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) or thioacetamide (TAA). The mice received F (0.75, 1.5 or 3 mg·kg·d, ip) for 4 weeks of fibrosis induction. We showed that F administration dose-dependently ameliorated CCl- 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 (0.1, 1, 10 μM) concentration-dependently inhibited the expression of α-SMA, and collagen I. In LX-2 cells, F 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 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 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 may thus be a potentially new effective pharmacotherapy for human liver fibrosis.