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Molecular characterization of regenerated cardiomyocytes derived from adult mesenchymal stem cells
Author(s) -
Fukuda Keiichi
Publication year - 2002
Publication title -
congenital anomalies
Language(s) - English
Resource type - Journals
eISSN - 1741-4520
pISSN - 0914-3505
DOI - 10.1111/j.1741-4520.2002.tb00847.x
Subject(s) - mesenchymal stem cell , microbiology and biotechnology , stromal cell , stem cell , biology , endocrinology , medicine , chemistry , cancer research
We recently isolated a cardiomyogenic (CMG) cell line from murine bone marrow stroma, and in this paper characterize regenerated cardiomyocytes derived from adult mesenchymal stem cells at the molecular level. Stromal cells were immortalized, exposed to 5‐azacytidine, and repeatedly screened for spontaneously beating cells. CMG cells began to beat spontaneously after 2 weeks, and beat synchronously after 3 weeks. They exhibited sinus‐node‐like or ventricular‐cell‐like action potentials. Analysis of the isoforms of contractile protein genes, such as of myosin and α‐actin, indicated that their phenotype was similar to that of fetal ventricular cardiomyocytes. The cells expressed Nkx2.5, GATA4, TEF‐1, and MEF2‐C mRNA before 5‐azacytidine exposure, and MEF2‐A and MEF2‐D after exposure. CMG cells expressed α 1A , α 1B , and α 1D ‐adrenergic receptor mRNA prior to differentiation, and β 1 , β 2 ‐adrenergic and M 1 , M 2 ‐muscarinic receptors after acquiring the cardiomyocyte phenotype. Phenylephrine induced phosphorylation of ERK1/ 2, and the phosphorylation was inhibited by prazosin. Isoproterenol increased the cAMP level 38‐fold and beating rate, cell motion, % shortening, and contractile velocity by 48%, 38%, 27%, and 51%, respectively, and the increases were blocked by CGP20712A (β 1 ‐selective blocker). Car‐bachol increased IP 3 32‐fold, and the increase was inhibited by AFDX116 (M 2 ‐selective blocker). These findings demonstrated that the regenerated cardiomyocytes were capable of responding to adrenergic and muscarinic stimulation. This new cell line provides a model for the study of cardiomyocyte transplantation.