A Systems Pharmacology Approach for Identifying Mechanisms Driving Cardiomyocyte Proliferation

Heart failure affects over 6 million Americans, with a projected 46% increase in prevalence by 2030. Most pathologies that lead to heart failure, including myocardial infarction and several cardiomyopathies, cause irreversible loss of cardiac muscle due to the limited regenerative capacity of adult mammalian hearts. Recent studies highlight the potential for enhancing cardiomyocyte proliferation as a therapeutic strategy. In this dissertation, we used a systems pharmacology approach combining high-content phenotypic screens and multi-omic analyses to discover novel targets and mechanisms regulating human iPSC-derived cardiomyocyte proliferation. First, we developed a high-content live-cell phenotypic assay to measure bona-fide cardiomyocyte proliferation, binucleation, and polyploidization. High-content phenotypic screening approaches identified 20 small molecule compounds that promoted proliferation without enhancing binucleation or polyploidy. We selected five highly active compounds with diverse putative targets, including ALK5 and CB1R, for subsequent multi-omic analyses. Unbiased transcriptome profiling of the pro-proliferative compounds revealed a common transcriptional program regulating cell cycle, DNA repair, and kinesin pathways. Using functional proteomic arrays, we discovered the compounds collectively activated multiple receptor tyrosine kinases including ErbB2 and VEGFR2. Network analysis integrating the common transcriptomic and proteomic signatures suggested multiple compound targets converged on MAPK and PI3K/AKT pathways to regulate proliferation and endoreplication. Collectively, this work identifies novel pro-proliferative compounds and elucidates common molecular mechanisms underlying compound-induced cardiomyocyte proliferation and endoreplication.