Abstract 13941: Non Viral Reprogramming of Skeletal Myoblasts to Stemness by Single Small Molecule: miR Profiling and Cardiac Regeneration
Background Reprogramming somatic cells into induced pluripotent stem cells typically require the enforced expression of several pluripotency determinant transcription factors, posing mutagenesis risks as exogenous genetic material. We report for the first time that skeletal myoblasts (SMs) can be induced to pluripotency by direct epigenetic reprogramming, with single small molecule without viral integration.
Methods & Results. SMs purified from young male Oct3/4-GFP+ transgenic mouse were treated with DNA methyltransferase inhibitor, “A”. Two weeks later, GFP+ colonies of SM derived iPS cells (IPS) expressing GFP and with morphological similarity of mouse embryonic stem cells(ESCs) were isolated and propagated in vitro. IPS were positive for alkaline phosphatase, had normal karyotype,developed teratoma in nude mice containing tissue comprising all three germ layers and expressed pluripotency genes SSEA1,Oct4,Sox2,KLF4,c-Myc and Nanog with panel of other pluripotency markers similar to ESCs. IPS derived embryoid bodies yielded spontaneously contracting cardiomyocytes like cells with morphological, molecular, and ultrastructural features similar to cardiomyocytes. These cells were positive for early and late cardiac markers such as myosin heavy chain, Gata4, Mef-2c and Nkx2.5, Connexin-43 (P <0.01vs native myoblasts). miR profiling showed abrogation of let-7 family in IPS whereas ESC specific family of miR-290-295 were upregulated which indicated that SiPS were similar to ESCs in their miR profile. In vivo studies in an experimental mouse model of acute myocardial infarction showed that at 4-week of engraftment of IPS cell derived cardiomyocytes (group4), there was extensive cell survival and myogenesis with attenuation of infarct size and improved heart function as compared to control DMEM without cells (group-1), native SMs (group-2), IPS cells (group-3)
Conclusions: This is the first report to demonstrate that skeletal myoblasts cells can be uniformly and efficiently differentiated into the IPS cells with single small molecule in vitro by a newly developed highly reproducible protocol and these cells can contribute to significant myocardial regeneration, attenuation of fibrosis and improved cardiac functions.
- © 2011 by American Heart Association, Inc.