Epigenetic Priming of Human Pluripotent Stem Cell-Derived Cardiac Progenitor Cells Accelerates Cardiomyocyte Maturation

Abstract

Human pluripotent stem cell‐derived cardiomyocytes (hPSC‐CMs) exhibit a fetal phenotype that limits in vitro and therapeutic applications. Strategies to promote cardiomyocyte maturation have focused interventions on differentiated hPSC‐CMs, but this study tests priming of early cardiac progenitor cells (CPCs) with polyinosinic‐polycytidylic acid (pIC) to accelerate cardiomyocyte maturation. CPCs were differentiated from hPSCs using a monolayer differentiation protocol with defined small molecule Wnt temporal modulation, and pIC was added during the formation of early CPCs. pIC priming did not alter the expression of cell surface markers for CPCs (>80% KDR+/PDGFRα+), expression of common cardiac transcription factors, or final purity of differentiated hPSC‐CMs (∼90%). However, CPC differentiation in basal medium revealed that pIC priming resulted in hPSC‐CMs with enhanced maturity manifested by increased cell size, greater contractility, faster electrical upstrokes, increased oxidative metabolism, and more mature sarcomeric structure and composition. To investigate the mechanisms of CPC priming, RNAseq revealed that cardiac progenitor‐stage pIC modulated early Notch signaling and cardiomyogenic transcriptional programs. Chromatin immunoprecipitation of CPCs showed that pIC treatment increased deposition of the H3K9ac activating epigenetic mark at core promoters of cardiac myofilament genes and the Notch ligand, JAG1. Inhibition of Notch signaling blocked the effects of pIC on differentiation and cardiomyocyte maturation. Furthermore, primed CPCs showed more robust formation of hPSC‐CMs grafts when transplanted to the NSGW mouse kidney capsule. Overall, epigenetic modulation of CPCs with pIC accelerates cardiomyocyte maturation enabling basic research applications and potential therapeutic uses. Stem Cells 2019;37:910–923

Notch Signaling Commits Mesoderm to the Cardiac Lineage

“…Fig. 4e, f) , and is consistent with recent reports showing no effect from DAPT treatment in standard differentiation conditions (Biermann et al, 2019). This suggests that either Notch signaling is not required for cardiomyocyte differentiation, or that the culture conditions provide a signaling environment that is sufficient to generate cardiomyocytes in the absence of active Notch signaling.…”

Cardiomyocyte Induction and Regeneration for Myocardial Infarction Treatment: Cell Sources and Administration Strategies

“…[30] Priming of human pluripotent stem cell-derived cardiac progenitor cells (CPCs) with polyinosinic-polycytidylic acid (pIC) promotes cell maturation by accelerating transcription of cardiac myofilaments and early onset of electromechanical contractions, as evidenced by the increased cell size, greater contractility, faster electrical upstrokes, increased oxidative metabolism, and more mature sarcomeric structure and composition. [31] Purification of CMs from human pluripotent stem cells is performed by magnetic or fluorescence activated cell sorting against specific cell surface markers or dyes. Using antibodies against vascular cell adhesion molecule 1 (VCAM1) and signal-regulatory protein alpha (SIRPA), VCAM1-and SIRPA-positive cells are enriched, and ≈95-98% of these positive cells were positive for cardiac troponin-T (TNNT2) and display molecular and functional features of cardiomyocytes.…”

“…[ 30 ] Priming of human pluripotent stem cell‐derived cardiac progenitor cells (CPCs) with polyinosinic‐polycytidylic acid (pIC) promotes cell maturation by accelerating transcription of cardiac myofilaments and early onset of electromechanical contractions, as evidenced by the increased cell size, greater contractility, faster electrical upstrokes, increased oxidative metabolism, and more mature sarcomeric structure and composition. [ 31 ]…”

Stem Cell Therapy of Myocardial Infarction: A Promising Opportunity in Bioengineering

“…The kinase insert domain protein receptor (KDR) and the platelet‐derived growth factor receptor α (PDGFR‐α) have been utilized as important surface markers of CPCs . KDR and PDGFR‐α are broadly expressed in the epicardium, myocardium, and endocardium, in both human fetal and diseased adult hearts.…”