General aim of this thesis, entitled Guide to the heart, was to explore the generation of multiple human pluripotent stem cell (hPSC)-derived cardiac subtypes and their application for selective... Show moreGeneral aim of this thesis, entitled Guide to the heart, was to explore the generation of multiple human pluripotent stem cell (hPSC)-derived cardiac subtypes and their application for selective pharmacology, understanding human cardiac development and cardiac repair.Approaches for the differentiation of hPSCs to cardiomyocytes (CMs) followed by purification from heterogeneous cultures are described. To generate subtype specific CMs, a protocol for the derivation and characterization of hPSC-derived CMs with atrial identity was developed. HPSC-derived atrial CMs have proven successful as pre-clinical pharmacological tool. The development of a human atrial reporter by CRISPR/Cas9-mediated knockin of red fluorescent mCherry into the genomic locus of atrial-enriched COUP-TFII allowed the selection of atrial and ventricular CMs. In addition, we evaluated the importance of COUP-TFII for atrial differentiation of hPSC and identified that COUP-TFII is dispensable for atrial differentiation of hPSCs. Importantly, hPSC-derived cardiac progenitors (CPCs) alleviated ventricular remodeling and fibrosis after transplantation to the heart in an acute myocardial infarction model in mice. This thesis ends with a review of the native cardiac environment during development, as well as the adult heart in health and disease. This was used to describe current knowledge regarding extracellular matrix preferences for engineering cardiac tissues from hPSC-CMs. Show less
In this thesis molecular and environmental cues in cardiac differentiation of mesenchymal stem cells were investigated. The main conclusions were that the cardiac differentiation potential of human... Show moreIn this thesis molecular and environmental cues in cardiac differentiation of mesenchymal stem cells were investigated. The main conclusions were that the cardiac differentiation potential of human mesenchymal stem cells negatively correlates with donor age. This in its own shows a negative relationship with connexin 43 levels in these cells. However, a causal relationship between connexin 43 expression levels and cardiomyogenic differentiation potential only exists for human mesenchymal stem cells from prenatal sources, i.e. while knockdown of connexin 43 expression in fetal human mesenchymal stem cells inhibits their ability to differentiate into cardiomyocytes, connexin 43 overexpression in adult human mesenchymal stem cells does not endow them with cardiomyogenic differentiation capacity. In addition, co-culture studies showed that the alignment and distribution of mesenchymal stem cells affect their electrical integration into host myocardium and are major determinants of their pro-arrhythmic risk. The mechanisms underlying the pro-arrhythmic effects of hMSCs are to some extent comparable to those of cardiac myofibroblasts, cells that are found in fibrotic myocardium Show less
