In vitro differentiation of mouse bone marrow mononuclear cells into hepatocyte-like cells.

AIM:: It is imperative to explore some ways to gain the functional hepatocytes for hepatocyte transplantation. Bone marrow stem cells can differentiate into hepatocytes in vivo and in vitro. We select fibroblast growth factor-4 (FGF-4), oncostatin M (OSM), hepatocyte growth factor (HGF) and epithermal growth factor (EGF) as differentiation factors, and design the appropriate directed differentiation medium in order to gain hepatocytes through directed differentiation of bone marrow stem cells. METHODS:: Bone marrow mononuclear cells (BMMCs) were cultured in the directed differentiation media including FGF-4, OSM, HGF and EGF. In the course of cell differentiation, cell morphology was observed, and the expression patterns of some genes of the hepatocyte were validated and confirmed by RT-PCR. The ALB-, and CK18-expressed cells were gone further step to be confirmed by Western blot analysis, immunofluorescence and flow cytometric analysis. Hepatocyte functional activity, including glycogen synthesis and urea production, were confirmed by periodic acid-Shiff (PAS) staining and urea assay. RESULTS:: Some epithelial-like cells or polygonal cells appeared in the directed differentiation medium within 12 days, and the number and sizes of colonies of epithelial-like cells or polygonal cells increased in the course of the cell directed differentiation. AFP, HNF-3ss, ALB and CK18 mRNA expressions first appeared within day 7, and lasted throughout the later directed differentiation. TTR, G-6-P and TAT mRNA expressions could be detected within day 14, and their expressions lasted in the course of the later directed differentiation. ALB and CK18 were confirmed to exist in the differentiated BMMCs by Western blot analysis. ALB was found in the cytoplasm and cell membrane, while CK18 scattered in the cytoplasm by immunofluorescent staining. On day 21,the ratio of ALB-positive cells was 69.45%, and the ratio of CK18-positive cells was 67.36%. The accumulation of glucogen was detected in the cytoplasm of the differentiated cells. The directed differentiated BMMCs produced urea 3 days later, and they produced urea in a time-dependent manner. CONCLUSIONS:: BMMCs could differentiate into hepatocytes or hepatocyte-like cells in the differentiation media including HGF, FGF-4, EGF, and OSM. These hepatocyte-like cells were identified at the gene level and protein level. Furthermore, these hepatocyte-like cells had some hepatocellular synthesis and metabolism functions.