Transcription factor-induced activation of cardiac gene expression in human c-kit+ cardiac progenitor cells.

Tareq Al-Maqtari,Bathri N Vajravelu,Kyung U Hong,Pengxiao Cao,Joseph B Moore,Afsoon Moktar,Roberto Bolli,Maurizio Pesce

doi:10.1371/journal.pone.0174242

Abstract

Although transplantation of c-kit+ cardiac progenitor cells (CPCs) significantly alleviates post-myocardial infarction left ventricular dysfunction, generation of cardiomyocytes by exogenous CPCs in the recipient heart has often been limited. Inducing robust differentiation would be necessary for improving the efficacy of the regenerative cardiac cell therapy. We assessed the hypothesis that differentiation of human c-kit+ CPCs can be enhanced by priming them with cardiac transcription factors (TFs). We introduced five different TFs (Gata4, MEF2C, NKX2.5, TBX5, and BAF60C) into CPCs, either alone or in combination, and then examined the expression of marker genes associated with the major cardiac cell types using quantitative RT-PCR. When introduced individually, Gata4 and TBX5 induced a subset of myocyte markers. Moreover, Gata4 alone significantly induced smooth muscle cell and fibroblast markers. Interestingly, these gene expression changes brought by Gata4 were also accompanied by morphological changes. In contrast, MEF2C and NKX2.5 were largely ineffective in initiating cardiac gene expression in CPCs. Surprisingly, introduction of multiple TFs in different combinations mostly failed to act synergistically. Likewise, addition of BAF60C to Gata4 and/or TBX5 did not further potentiate their effects on cardiac gene expression. Based on our results, it appears that GATA4 is able to potentiate gene expression programs associated with multiple cardiovascular lineages in CPCs, suggesting that GATA4 may be effective in priming CPCs for enhanced differentiation in the setting of stem cell therapy.

Highlights

In contrast to the long-standing belief that the mammalian heart is a post-mitotic or terminally differentiated organ, previous reports have demonstrated that the adult mammalian heart possesses a capacity of cardiomyocyte renewal [1,2,3,4,5]
The results show that among the transcription factors (TFs) tested, Gata4 is effective in initiating expression of genes of multiple lineages when overexpressed in c-kit+ cardiac progenitor cells (CPCs)
One of the limitations of the current regenerative CPC therapy for ischemic cardiomyopathy is the lack of robust de novo differentiation of the transplanted cells in the host myocardium [10, 14]. The cause of this is unknown, increasing the cardiogenic differentiation potential of CPCs may further enhance the efficacy of the CPC therapy. In support of this notion, Behfar and colleagues have shown that treatment of cells with ‘cardiogenic cocktail’ prior to transplantation augments the therapeutic benefit of the bone marrow mesenchymal stem cells in chronic ischemic cardiomyopathy [30]

Summary

Introduction

In contrast to the long-standing belief that the mammalian heart is a post-mitotic or terminally differentiated organ, previous reports have demonstrated that the adult mammalian heart possesses a capacity of cardiomyocyte renewal [1,2,3,4,5]. Beltrami and colleagues first described a unique resident cardiac cell population with characteristics of stem cells in the rat heart [6]. Similar to Gata, TBX5 failed to induce the full range of cardiomyocyte markers, including α- and β-MHC and BNP (which is closely related to ANP in regard to function and gene regulation), by 2 weeks (data not shown and Fig 2). Similar to TBX5, NKX2.5 expression only resulted in a marginal increase in KDR and connexin 40 (GJA5)

Methods

Results

Conclusion