Abstract 13303: Identification of Critical Six Transcriptional Factors for Reprogramming of Mouse Adipose-Derived Regenerative Cells Toward Cardiomyocytes and Its Therapeutic Effect

Abstract

Background: Adipose-derived regenerative cells (ADRCs) are promising stem cells for regenerative medicine that are easy to harvest from adipose tissues and can expand in vitro . While ADRCs can differentiate into mesodermal lineage cells including adipocytes, osteocytes, and chondrocytes, little is known about differentiating adult ADRCs into mature cardiomyocytes. Objective: The aim of this study was to explore how to differentiate adult mouse ADRCs into cardiomyocytes efficiently and test their effect on the myocardial infarction mouse model in vivo . Method and Results: We performed differential expression analysis to identify transcriptional factors which were upregulated in developing mice heart (E11.5) compared with ADRCs. We systemically screened the combinations of the required transcription factors in ADRCs derived from αMHC-EGFP reporter mice. Here, we identified the following six genes; Baf60c , Gata4 , Gata6 , Klf15 , Mef2a , Myocd , not more or less, as the best combination to efficiently induce αMHC in ADRCs. Fluorescence-activated cell sorting analysis showed that 3.0±0.61% (n=3) ADRCs were positive for αMHC after introducing these six factors. In addition, quantitative PCR demonstrated that several other marker genes of mature cardiomyocytes, including Actc1 , Tnnt2 , Ttn , Fhod3 , were confirmed to be upregulated by six factors. Immunocytochemical staining showed that most of the induced ADRCs had fibrous conformation of sarcomeric α-actin. Moreover, the gene expression pattern of the cells showed upregulation of genes associated with cardiac muscle cell differentiation. Finally, injection of the induced ADRCs into acute myocardial infarction lesions in vivo resulted in the improvement of survival rate (p=0.028, n=32), fractional shortening (p=0.012, n=7, 15), and the reduction of infarction scar area compared to the injection of ADRCs without induction (p=0.029, n=7). The induced ADRCs could survive in situ and continued to express the cardiac troponin T protein for four weeks after injection. Conclusions: The combination of six transcriptional factors could induce cardiomyocyte-like gene expression patterns on adult ADRCs. The induced ADRCs could have a therapeutic effect on an experimental ischemic heart model in vivo .