Tonsil-derived Mesenchymal Stem Cells Ameliorate CCl(4)–induced Liver Fibrosis in Mice via Autophagy Activation

Liver transplantation is the treatment of choice for chronic liver failure, although it is complicated by donor shortage, surgery-related complications, and immunological rejection. Cell transplantation is an alternative, minimally invasive treatment option with potentially fewer complications. We used human palatine tonsil as a novel source of mesenchymal stem cells (T-MSCs) and examined their ability to differentiate into hepatocyte-like cells in vivo and in vitro. Carbon tetrachloride (CCl(4)) mouse model was used to investigate the ability of T-MSCs to home to the site of liver injury. T-MSCs were only detected in the damaged liver, suggesting that they are disease-responsive. Differentiation of T-MSCs into hepatocyte-like cells was confirmed in vitro as determined by expression of hepatocyte markers. Next, we showed resolution of liver fibrosis by T-MSCs via reduction of TGF-β expression and collagen deposition in the liver. We hypothesized that autophagy activation was a possible mechanism for T-MSC-mediated liver recovery. In this report, we demonstrate for the first time that T-MSCs can differentiate into hepatocyte-like cells and ameliorate liver fibrosis via autophagy activation and down-regulation of TGF-β. These findings suggest that T-MSCs could be used as a novel source for stem cell therapy targeting liver diseases.