Liver fibrosis is characterized by formation of
scar tissue in the liver. The role of STAT3 signaling has been implicated on activating hepatic stellate cells (HSC) to myofibroblast-like cells in
liver fibrosis. Major factors that activate STAT3 signaling are TGF-β1 and
IL-6, which are upregulated in the liver in patients afflicted with
liver fibrosis. Recent reports indicate that not only
IL-6, but also the non-canonical signaling pathway of TGF-β1 is associated with STAT3 signaling. In this study, we demonstrate a new function of the STAT3 inhibitor,
STX-0119, in
liver fibrosis.
STX-0119 is an inhibitor of STAT3 dimerization, which is required for nuclear localization of STAT3. We first investigated the anti-fibrotic effect of
STX-0119 in in vitro experiments. Exposure to
STX-0119 inhibited the nuclear localization of STAT3 in HSCs, resulting in decreased expression of its target genes, such as col1a1 and αSMA. In addition,
STX-0119 also inhibited the TGF-β1/IL-6-induced activation of HSCs. Next, we examined the in vivo effect of
STX-0119 in the
liver fibrosis mouse model using
thioacetamide (TAA) and
carbon tetrachloride (CCl4).
STX-0119 attenuated the TAA-induced
liver fibrosis by inhibiting activation of HSCs to myofibroblast-like cells. Consistent with the in vivo results using TAA-induced
liver fibrosis model, treatment of
STX-0119 similarly attenuated CCl4-induced
liver fibrosis. In conclusion, we believe that
STX-0119 inhibits the development of
liver fibrosis by blocking the activation of hepatic stellate cells. These results indicate that
STX-0119 is a potential new therapeutic strategy to prevent
disease progression to
cirrhosis.