ABSTRACT
Bone marrow mesenchymal stromal cells (BM-MSCs) with regenerative potential have been identified in heart. Whether these cells become new cardiac lineage cells by phenomena of transdifferentiation or fusion is also being investigated. Although, these mechanisms give cardiomyocytes, it has to be considered that MSCs transplantation could carry out ossification and calcification processes. An alternative might be the use of myocytes; however, the problem is the arrythmia. For those reasons, is that we investigated how to obtain cardiomyocyte-like cells from human MSCs (hMSCs). The aim of the present work was to evaluate a nuclear reprogramming of the hMSCs by a neonatal rat cardiomyocytes extract (EX) using Streptolysin O (SLO) treatment. hMSCs treated with 57.5ng/ml SLO presented ball-like, stick-like and myotube-like morphology. In the absence of cardiomyogenic stimuli, hMSCs expressed markers of cardiac phenotype-like sarcomeric alpha-actinin, connexin-43 and GATA-4. However, when hMSCs were treated with SLO+EX or 10 microM of 5-azacytidine (5-AZA), the expression of these markers were significantly increased and furthermore, expressed SERCA-2, cardiac Troponin I, beta-MyHC, desmin, MLC-2a and MLC-2v thus showing the phenotype of mature cardiomyocytes. PCR analysis showed that cardiomyocyte-related genes, such as beta1-adrenergic receptor (beta1-AR), MLC-2a and cardiac Troponin T, were expressed after SLO+EX treatment like with 5-AZA. We concluded that the extract of neonatal rat cardiomyocytes could promote a nuclear modification of hMSCs to cardiomyogenic-like cells differentiation. Since the 5-AZA treatment appears to be genotoxic and taking into account the obtained results, the nuclear reprogramming by cell extract may be an approach leading to the identification of soluble factors that drives the reprogramming.