(T1253) FTO AS A KEY REGULATOR OF MESODERM AND CARDIAC MESODERM SPECIFICATION IN HUMAN INDUCED PLURIPOTENT STEM CELL-DERIVED CARDIOMYOCYTE DIFFERENTIATION
Hong Kong University of Science and Technology, China (People's Republic)
Abstract: Cardiomyocyte differentiation from human induced pluripotent stem cells (hiPSCs) provides an unlimited resource for studying developmental processes and disease progression. N6-methyladenosine (m6A), the most abundant modification in mammalian mRNA, is implicated in various biological processes, yet its specific function in cardiac commitment remains elusive. Here, we found a significant increase in the expression levels of the demethylation enzyme FTO during the early stages of hiPSC-derived cardiomyocyte (hiPSC-CM) differentiation, followed by a decrease in terminally differentiated cells, suggesting a dynamic regulation of m6A modification during cardiac fate determination. By using the FB23-2, a compound that selectively inhibits the demethylation function of FTO, we confirmed the stage-specific requirement of FTO during hiPSC-CM differentiation. Our findings indicated that FTO is crucial for the determination of the mesoderm and cardiac mesoderm, essential stages in early cardiac lineage specification, while it appears to have no significant influence on the induction of cardiac progenitor cells. Enrichment analyses of gene ontology (GO) showed that downregulated genes in FTO inhibition group are enriched in heart development, cardiac chamber formation, and ventricular cardiac muscle cell differentiation. Mechanistically, we demonstrated that FTO is vital for the activation of key cardiac transcription factors, such as NKX2-5 and TBX5. These results highlight the intricate regulatory network governed by m6A modification in cardiac differentiation. In conclusion, our study identifies FTO as an essential regulator of hiPSC-CM differentiation and underscores the critical role of precise tuning of m6A modification in facilitating successful cardiac differentiation.
