No abstract

Background: Molecular targeted chemotherapies have been shown to significantly improve cancer patient outcomes, but often cause cardiovascular side effects that limit their use and impair patients' quality of life. Cardiac dysfunction induced by these therapies, especially trastuzumab, shows a distinct cardiotoxic clinical phenotype compared to cardiotoxicity induced by conventional chemotherapies. Methods: We employed the human induced pluripotent stem cell-derived cardiomyocyte (iPSC-CM) platform to determine the underlying cellular mechanisms in trastuzumab-induced cardiac dysfunction. We assessed the effects of trastuzumab on structural and functional properties in iPSC-CMs from healthy individuals and performed RNA-sequencing (RNA-seq) to further examine the effect of trastuzumab on iPSC-CMs. We also generated iPSCs from patients receiving trastuzumab and examined whether patients' phenotype could be recapitulated in vitro using patient-specific iPSC-CMs.

Background Human-induced pluripotent stem cells (iPSCs) are a potentially unlimited source for generation of cardiomyocytes (iPSC-CMs). However, current protocols for iPSC-CM derivation face a number of challenges, including variability in somatic cell sources and inconsistencies in cardiac differentiation efficiency. Objectives We aimed to assess the effect of epigenetic memory on differentiation and function of iPSC-CMs generated from somatic cell sources of cardiac versus non-cardiac origins. Methods Cardiac progenitor cells (CPCs) and skin fibroblasts from the same donors were reprogrammed into iPSCs and differentiated into iPSC-CMs via embryoid body and monolayer-based differentiation protocols. Results Differentiation efficiency was found to be higher in CPC-derived iPSC-CMs (CPC-iPSC-CMs) than in fibroblast-derived iPSC-CMs (Fib-iPSC-CMs). Gene expression analysis during cardiac differentiation demonstrated upregulation of cardiac transcription factors in CPC-iPSC-CMs, including NKX2-5, MESP1, ISL1, HAND2, MYOCD, MEF2C, and GATA4. Epigenetic assessment revealed higher methylation in the promoter region of NKX2-5 in Fib-iPSC-CMs compared to CPC-iPSC-CMs. Epigenetic differences were found to dissipate with increased cell passaging, and a battery of in vitro assays revealed no significant differences in their morphological and electrophysiological properties at early passage. Finally, cell delivery into small animal myocardial infarction (MI) model indicated that CPC-iPSC-CMs and Fib-iPSC-CMs possess comparable therapeutic capabilities in improving functional recovery in vivo. Conclusions This is the first study to compare differentiation of iPSC-CMs from human CPCs versus human fibroblasts from the same donors. We demonstrate that while epigenetic memory improves differentiation efficiency of cardiac versus non-cardiac somatic cell source in vitro, it does not contribute to improved functional outcome in vivo.