Promoting effect of 5-azacytidine on the myogenic differentiation of bone marrow stromal cells.
Bone marrow stromal cells (BMSC) can differentiate into various cell types including myocytes, which may be valuable in cellular therapy of myocardial infarction. In an attempt to increase the myogenic commitment of BMSC, we investigated the extent of conversion induced by the demethylation agent 5-azacytidine. BMSC isolated from the adult rat tibia were exposed in culture to 5microM 5-azacytidine for 24h, 1 day after seeding. The treatment was repeated at weekly intervals and the expression of muscle-specific proteins and genes was assessed. The results revealed that cultured cells lost the native expression of osteocalcin and alkaline phosphatase as a function of time and began to express connexin 43. Exposure to 5-azacytidine of BMSC induced, at 14 days, a myocyte-resembling phenotype that included the expression of muscle-specific proteins (sarcomeric alpha-actin, troponin T, desmin, alpha-actinin, and GATA-4) and genes (GATA-4, myoD, desmin, and alpha-actinin), numerous mitochondria and myofilaments; however, the latter did not form sarcomeres. Although some of these myogenic markers also appeared in untreated cells, exposure to 5-azacytidine induced an enhanced response of calcium channels, as well as a threefold increase in desmin and myoD gene expression and a twofold increase in alpha-actinin gene and protein expression above the control values. In conclusion, the results demonstrate a promoting effect of 5-azacytidine on the expression of muscle-specific proteins and genes in BMSC in culture. Notably, the myogenic differentiation takes place over a short period of time. Priming of mesenchymal cells to cardiomyogenic differentiation may have significant applications in cellular approaches to ameliorate muscle loss after myocardial ischemia.
Institute of Cellular Biology and Pathology "N. Simionescu", 8 B.P. Hasdeu Street, Bucharest 050568, Romania.
Alexandrina
A
Burlacu
Ana-Maria
AM
Rosca
Horia
H
Maniu
Irina
I
Titorencu
Emanuel
E
Dragan
Victor
V
Jinga
Maya
M
Simionescu
D000818:Animals; D001374:Azacitidine / Q000494:pharmacology*; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002454:Cell Differentiation; D018031:Connexin 43 / Q000378:metabolism; D032342:Muscle Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D024510:Muscle Development; D009124:Muscle Proteins / Q000378:metabolism; D051381:Rats; D017154:Stromal Cells / Q000187:drug effects / Q000378:metabolism*
D018031:Connexin 43; D009124:Muscle Proteins; D001374:Azacitidine