Sera from liver failure patients and a demethylating agent stimulate transdifferentiation of murine bone marrow cells into hepatocytes in coculture with nonparenchymal liver cells

Background/Aims: The plasticity of bone marrow cells (BMCs) is shown by their ability to differentiate into mesenchymal as well as endodermal and ectodermal lineages. Transdifferentiation of BMCs into hepatocytes has also been demonstrated, both in vitro and in vivo. In the present study we investigated the effects of liver nonparenchymal cells (NPCs) and sera from liver failure patients (HSLF) on the in vitro transdifferentiation of murine BMCs into hepatocytes. Methods: Liver NPCs from wild-type mice, and 5-azacytidine-treated BMCs from green fluorescence protein transgenic mice, were cocultured in medium containing HSLF in combination with several cytokines. Hepatocyte-specific gene expression in BMCs was identified by immunocytochemistry and reverse transcription-polymerase chain reaction. Results: Bone marrow cell-derived hepatocyte-like colonies appeared after several days of coculture in medium containing HSLF, oncostatin M (OSM) and hepatocyte growth factor (HGF). These colonies expressed hepatocyte-specific genes. Transdifferentiation was enhanced by 5-azacytidine treatment, and by HSLF, OSM and HGF. It did not take place when the BMCs were separated from the NPCs in a dual chamber dish, or cultured with other mesenchymal cells. Conclusions: Direct interaction of murine BMCs with liver NPCs, as well as soluble factors in the HSLF and a demethylating agent, strongly stimulate transdifferentiation into hepatocytes. (C) 2003 European Association for the Study of the Liver. Published by Elsevier Science B.V. All rights reserved.