by Internet Medical Society
Background: A microRNA, miR499c, has been discovered in human fetal heart which rescues mutant hearts in cardiac nonfunction mutant axolotl (salamander) embryos and also induces the differentiation of mouse embryonic stem cells (mESCs) to form into definitive cardiomyocytes. Results: Eight days after transfection with MiR499c, approximately 75-80% of the stem cells develop typical cardiomyocyte morphologies and express the cardiac specific marker, Troponin T, as well as the muscle proteins, tropomyosin and α-actinin, as shown by immunohistochemical staining. qRT-PCR confirms that transfection with MiR499c increases expression of troponin T and tropomyosin and further shows an increased expression of myosin as well as Wnt11 and Sox17. Untreated controls do not show significant expression of these proteins. Conclusion: It is evident that the miR499c induces the development of contractile myofibrils characteristic of striated cardiac muscle indicating that the miR499c microRNA plays an important role in the differentiation of cardiomyocytes (Full text).