Preliminary MS-based analysis of human iPSC generation and differentiation into cardiomyocytes: molecular insights from a murine post-infarction transplantation model

Somatic cell reprogramming and the generation of induced pluripotent stem cells (iPSCs) represent significant advances with potential applications in regenerative medicine. The use of iPSC-derived cardiomyocytes (iPSC-CMs) has emerged as a promising experimental approach for investigating cardiac repair following myocardial infarction. However, we are still very far from understanding the molecular mechanisms underlying somatic cell reprogramming with subsequent cardiomyocyte differentiation, as well as the molecular response of the infarcted myocardium to iPSC-CM transplantation. In this study, we used a comprehensive mass spectrometry-based proteomic and metabolomic approach to analyze the metabolic processes and signaling pathways involved in the induction of pluripotency in human myoblasts and the subsequent differentiation of the derived iPSCs into cardiomyocytes. The obtained iPSC-CMs were applied in a mouse model of myocardial infarction. We demonstrated that during the cell reprogramming and cardiomyocyte differentiation, cells shift their energy-producing phenotype from mitochondrial oxidative phosphorylation towards a glycolytic phenotype (early phase of reprogramming), and they adopt an aerobic phenotype again after day 4 of cardiomyogenesis. We also revealed that transplantation of iPSC-CMs into the infarcted heart was associated with measurable changes in the myocardial proteome, including altered abundance of proteins involved in cardiac contractile function, tissue remodeling and repair. Although these molecular changes were not accompanied by a significant improvement in cardiac function, they demonstrate that iPSC-CM transplantation is associated with a detectable molecular response within the post-infarction myocardium.