Hepatocyte growth factor combined with insulin like growth factor-1 improves expression of GATA-4 in mesenchymal stem cells cocultured with cardiomyocytes

Background In a suitable microenvironment,bone marrow mesenchymal stem cells(BMSCs)can transdifferentiateinto myocardial cells whose special gene can be expressed as structural proteins.Growth factor(GF)plays an importantrole in the cell migration,survival and differentiation.However,the effect of GF on the cellular differentiation is not wellunderstood.In this study,the hepatocyte growth factor(HGF)and insulin like growth factor-1(IGF-1)were used in themixed culture of BMSCs and myocardial cells and the effects of these growth factors on the GATA-4 expression ofBMSCs were investigated.Methods BMSCs were isolated from the marrow of rabbit femurs and tibias and foetal rabbit ventricular myocytes wereisolated with trypsin sequential digestion.These two kinds of cells were cocultured in a ratio of 1:1 for 6 weeks;cocultured cells with added HGF and IGF-1 were the experimental group.The differentiated BMSCs were collected usingthe laser capture,microdissection system and their RNA isolated.Immunocytochemical staining,transmission electronmicroscopy and reverse transcription-polymerase chain reaction were used to evaluate the transformation of the stemcells into cardiomyocytes like cells.Results When cultured separately,BMSCs did not express α-actin and the stem cells had many nucleoli.However,when cocultured with cardiomyocytes,BMSCs expressed α-actin and the cardiac transcription factor GATA-4 andshowed cardiomyocyte like ultrastructure.In comparison with the control group,the experimental group exhibited theenhanced expression level of GATA-4.The GATA-4 expression of BMSCs increased gradually following the addition ofHGF and IGF-1,reached the maximal level after two weeks and decreased slightly thereafter.Conclusions BMSCs can transdifferentiate into cardiomyocytes like cells and express the cardiac transcription factorGATA-4 after being cocultured with myocardial cells.HGF and IGF-1 can stimulate transdifferentiation of BMSCs intocardiac phenotype and enhance the expression of GATA-4.These results indicate that growth factors have a greatpotential in clinical cellular therapy.