Analysis of G protei

Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 59307126

Human embryonic stem cells (hESCs) are pluripotent stem cells that can give rise to all cell types in the human body. hESC lines could become an important resource for both drug screening in a human context and cell replacement therapy strategies. Cardiomyocytes arise from a mesodermal progenitor subpopulation of hESCs, which is characterized by the expression of the transcription factor brachyury and the tyrosine kinase receptor Flk1. Aim of this research proposal is to compare the expression profile of G protein-coupled receptors (GPCRs) of undifferentiated hESCs with that of embryonic cells after differentiation to mesodermal progenitors. We approach this comparison with a novel high-fidelity and high-sensitivity RT-PCR-based microarray that has been developed by the applicant during his postdoctoral period at the NIH. The assay establishes the expression profile of all known human GPCR-cDNAs, sequences that are largely overlooked in traditional microarrays. Comparison of both receptor profiles will identify candidate receptors, which are upregulated/induced during mesodermal differentiation. Ligands to these receptors will be tested for their ability to modulate mesodermal and cardiac differentiation of hESCs in embryoid body assays. Functional tests of differentiated cardiomyocytes will be performed in engineered heart tissue assays - developed in the applicants present institute. We expect that the project will, on the one hand, improve the understanding of cardiac differentiation in hESCs and, on the other hand, provide new tools to obtain pure cardiac progenitors from hESC for cardiac regeneration.