title: Involvement of Rictor/mTORC2 in cardiomyocyte differentiation of mouse embryonic stem cellsin vitro.
abstract: Rictor is a key regulatory/structural subunit of the mammalian target of rapamycin complex 2 (mTORC2) and is required for phosphorylation of Akt at serine 473. It plays an important role in cell survival, actin cytoskeleton organization and other processes in embryogenesis. However, the role of Rictor/mTORC2 in the embryonic cardiac differentiation has been uncovered. In the present study, we examined a possible link between Rictor expression and cardiomyocyte differentiation of the mouse embryonic stem (mES) cells. Knockdown of Rictor by shRNA significantly reduced the phosphorylation of Akt at serine 473 followed by a decrease in cardiomyocyte differentiation detected by beating embryoid bodies. The protein levels of brachyury (mesoderm protein), Nkx2.5 (cardiac progenitor cell protein) and α-Actinin (cardiomyocyte biomarker) decreased in Rictor knockdown group during cardiogenesis. Furthermore, knockdown of Rictor specifically inhibited the ventricular-like cells differentiation of mES cells with reduced level of ventricular-specific protein, MLC-2v. Meanwhile, patch-clamp analysis revealed that shRNA-Rictorsignificantly increased the number of cardiomyocytes with abnormal electrophysiology. In addition, the expressions and distribution patterns of cell-cell junction proteins (Cx43/Desmoplakin/N-cadherin) were also affected in shRNA-Rictorcardiomyocytes. Taken together, the results demonstrated that Rictor/mTORC2 might play an important role in the cardiomyocyte differentiation of mES cells. Knockdown of Rictor resulted in inhibiting ventricular-like myocytes differentiation and induced arrhythmias symptom, which was accompanied by interfering the expression and distribution patterns of cell-cell junction proteins. Rictor/mTORC2 might become a new target for regulating cardiomyocyte differentiation and a useful reference for application of the induced pluripotent stem cells.
authors.affiliation: Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou 310058, CHINA.
authors.forename: Bei
authors.initials: B
authors.lastname: Zheng
authors.affiliation: Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou 310058, CHINA.
authors.forename: Jiadan
authors.initials: J
authors.lastname: Wang
authors.affiliation: Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou 310058, CHINA.
authors.forename: Leilei
authors.initials: L
authors.lastname: Tang
authors.affiliation: Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou 310058, CHINA.
authors.forename: Chao
authors.initials: C
authors.lastname: Tan
authors.affiliation: Undergraduate students in Research Training Project at Zhejiang University.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Zhao
authors.affiliation: Undergraduate students in Research Training Project at Zhejiang University.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: The Population Council at the Rockefeller University, New York, NY 10021, USA.; Institute of Reproductive Biomedicine, the 2nd Affiliated Hospital of Wenzhou Medical University, Wenzhou 325027, CHINA.
authors.forename: Renshan
authors.initials: R
authors.lastname: Ge
authors.affiliation: Institute of Pharmacology and Toxicology, Zhejiang University, Hangzhou 310058, CHINA.
authors.forename: Danyan
authors.initials: D
authors.lastname: Zhu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D004594:Electrophysiology; D005434:Flow Cytometry; D000076225:Mechanistic Target of Rapamycin Complex 2; D051379:Mice; D000066450:Mouse Embryonic Stem Cells / Q000378:metabolism* / Q000502:physiology; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation / Q000235:genetics / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism; D000076226:Rapamycin-Insensitive Companion of mTOR Protein; D058570:TOR Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D046912:Multiprotein Complexes; D000076226:Rapamycin-Insensitive Companion of mTOR Protein; C525637:rictor protein, mouse; D000076225:Mechanistic Target of Rapamycin Complex 2; D051057:Proto-Oncogene Proteins c-akt; D058570:TOR Serine-Threonine Kinases
keywords: Rictor/mTORC2; cardiomyocyte differentiation; cell-cell junction; electrophysiology.; embryonic stem cell