Abstract | RATIONALE: Although rare cardiomyogenesis is reported in the adult mammalian heart, whether this results from differentiation or proliferation of cardiomyogenic cells remains controversial. The tumor suppressor genes RB1 ( retinoblastoma) and CDKN2a ( cyclin-dependent kinase inhibitor 2a) are critical cell-cycle regulators, but their roles in human cardiomyogenesis remains unclear. OBJECTIVE: We hypothesized that developmental activation of RB1 and CDKN2a cooperatively cause permanent cell-cycle withdrawal of human cardiac precursors (CPCs) driving terminal differentiation into mature cardiomyocytes, and that dual inactivation of these tumor suppressor genes promotes myocyte cell-cycle reentry. METHODS AND RESULTS: Directed differentiation of human pluripotent stem cells (hPSCs) into cardiomyocytes revealed that RB1 and CDKN2a are upregulated at the onset of cardiac precursor specification, simultaneously with GATA4 (GATA- binding protein 4) homeobox genes PBX1 ( pre-B-cell leukemia transcription factor 1) and MEIS1 (myeloid ecotropic viral integration site 1 homolog), and remain so until terminal cardiomyocyte differentiation. In both GATA4+ hPSC cardiac precursors and postmitotic hPSC-cardiomyocytes, RB1 is hyperphosphorylated and inactivated. Transient, stage-specific, depletion of RB1 during hPSC differentiation enhances cardiomyogenesis at the cardiac precursors stage, but not in terminally differentiated hPSC-cardiomyocytes, by transiently upregulating GATA4 expression through a cell-cycle regulatory pathway involving CDKN2a. Importantly, cytokinesis in postmitotic hPSC-cardiomyocytes can be induced with transient, dual RB1, and CDKN2a silencing. The relevance of this pathway in vivo was suggested by findings in a porcine model of cardiac cell therapy post-MI, whereby dual RB1 and CDKN2a inactivation in adult GATA4+ cells correlates with the degree of scar size reduction and endogenous cardiomyocyte mitosis, particularly in response to combined transendocardial injection of adult human hMSCs (bone marrow-derived mesenchymal stromal cells) and cKit+ cardiac cells. CONCLUSIONS: Together these findings reveal an important and coordinated role for RB1 and CDKN2a in regulating cell-cycle progression and differentiation during human cardiomyogenesis. Moreover, transient, dual inactivation of RB1 and CDKN2a in endogenous adult GATA4+ cells and cardiomyocytes mediates, at least in part, the beneficial effects of cell-based therapy in a post-MI large mammalian model, a finding with potential clinical implications.
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Authors | Konstantinos E Hatzistergos, Adam R Williams, Derek Dykxhoorn, Michael A Bellio, Wendou Yu, Joshua M Hare |
Journal | Circulation research
(Circ Res)
Vol. 124
Issue 8
Pg. 1184-1197
(04 12 2019)
ISSN: 1524-4571 [Electronic] United States |
PMID | 30744497
(Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)
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Chemical References |
- GATA4 Transcription Factor
- GATA4 protein, human
- MEIS1 protein, human
- Myeloid Ecotropic Viral Integration Site 1 Protein
- Pre-B-Cell Leukemia Transcription Factor 1
- PBX1 protein, human
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Topics |
- Animals
- Cell Cycle
(physiology)
- Cell Differentiation
(physiology)
- Cell Line
- GATA4 Transcription Factor
(genetics, metabolism)
- Gene Silencing
- Genes, Retinoblastoma
(physiology)
- Genes, p16
(physiology)
- Humans
- Induced Pluripotent Stem Cells
(cytology, physiology)
- Myeloid Ecotropic Viral Integration Site 1 Protein
(genetics, metabolism)
- Myocytes, Cardiac
(physiology)
- Pluripotent Stem Cells
(transplantation)
- Pre-B-Cell Leukemia Transcription Factor 1
(genetics, metabolism)
- Swine
- Up-Regulation
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