title: Triiodothyronine promotes cardiac differentiation and maturation of embryonic stem cells via the classical genomic pathway.
abstract: Embryonic stem cells (ESCs) can differentiate into functional cardiomyocytes and thus represent a promising cell source for cardiac regenerative therapy. Nevertheless, the therapeutic application of ESC-derived cardiomyocytes is limited by the low efficacy of the current protocol for cardiac differentiation and their immature phenotypes. Although thyroid hormone is essential for normal cardiac development and function, its role in the cardiac differentiation of ESCs, as well as the maturation of ESC-derived cardiomyocytes, remains unclear. In this study, we examined the cardiac differentiation of murine ESCs in the presence of T(3) for 7 d using flow cytometry, RT-PCR, cellular electrophysiology study, and confocal calcium imaging. Compared with control conditions, T(3) supplementation increased the number of ESC-derived cardiomyocytes and was accompanied by up-regulation of a panel of cardiac markers, including Nkx2.5, myosin light chain-2V, as well as alpha- and beta-myosin heavy chain. More importantly, electrophysiological study revealed that ESC-derived cardiomyocytes exhibited more adult-like phenotypes after T(3) supplementation based on action potential characteristics. They also exhibited more adult-like calcium homeostasis properties. These phenotypic changes were associated with up-regulation of sarco(endo)plasmic reticulum calcium ATPase-2a and ryanodine receptor-2 expression. In addition, the classical (genomic) pathway was shown to be involved in T(3)-induced cardiac differentiation of ESCs. Our results show that T(3) supplementation promotes cardiac differentiation of ESCs and enhances maturation of electrophysiological, as well as calcium homeostasis, properties of ESC-derived cardiomyocytes.
authors.affiliation: Cardiology Division, Department of Medicine, The University of Hong Kong, Queen Mary Hospital, Hong Kong, China.
authors.forename: Yee-Ki
authors.initials: YK
authors.lastname: Lee
authors.forename: Kwong-Man
authors.initials: KM
authors.lastname: Ng
authors.forename: Yau-Chi
authors.initials: YC
authors.lastname: Chan
authors.forename: Wing-Hon
authors.initials: WH
authors.lastname: Lai
authors.forename: Ka-Wing
authors.initials: KW
authors.lastname: Au
authors.forename: Chung-Yee Jenny
authors.initials: CY
authors.lastname: Ho
authors.forename: Lai-Yung
authors.initials: LY
authors.lastname: Wong
authors.forename: Chu-Pak
authors.initials: CP
authors.lastname: Lau
authors.forename: Hung-Fat
authors.initials: HF
authors.lastname: Tse
authors.forename: Chung-Wah
authors.initials: CW
authors.lastname: Siu
mesh_terms: D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000235:genetics; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D016678:Genome / Q000235:genetics*; D051379:Mice; D009206:Myocardium / Q000166:cytology* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D014284:Triiodothyronine; D002110:Caffeine; D002118:Calcium