title: mTOR and the differentiation of mesenchymal stem cells.
abstract: The mammalian target of rapamycin (mTOR), an evolutionarily conserved serine-threonine protein kinase, belongs to the phosphoinositide 3-kinase (PI3K)-related kinase family, which contains a lipid kinase-like domain within their C-terminal region. Recent studies have revealed that mTOR as a critical intracellular molecule can sense the extracellular energy status and regulate the cell growth and proliferation in a variety of cells and tissues. This review summarizes our current understanding about the effects of mTOR on cell differentiation and tissue development, with an emphasis on the lineage determination of mesenchymal stem cells. mTOR can promote adipogenesis in white adipocytes, brown adipocytes, and muscle satellite cells, while rapamycin inhibits the adipogenic function of mTOR. mTOR signaling may function to affect osteoblast proliferation and differentiation, however, rapamycin has been reported to either inhibit or promote osteogenesis. Although the precise mechanism remains unclear, mTOR is indispensable for myogenesis. Depending on the cell type, rapamycin has been reported to inhibit, promote, or have no effect on myogenesis.
authors.affiliation: Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Department of Physiology and Pathophysiology, Health Science Center, Peking University, Beijing, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Xiang
authors.forename: Jing
authors.initials: J
authors.lastname: Zhao
authors.forename: Geyang
authors.initials: G
authors.lastname: Xu
authors.forename: Yin
authors.initials: Y
authors.lastname: Li
authors.forename: Weizhen
authors.initials: W
authors.lastname: Zhang
mesh_terms: D050156:Adipogenesis / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D019070:Cell Lineage; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000502:physiology*; D035683:MicroRNAs / Q000502:physiology; D024510:Muscle Development / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D015398:Signal Transduction / Q000502:physiology; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases / Q000502:physiology*
chemical_list: D035683:MicroRNAs; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus