title: High glucose induces differentiation and adipogenesis in porcine muscle satellite cells via mTOR.
abstract: The present study investigated whether the mammalian target of rapamycin (mTOR) signal pathway is involved in the regulation of high glucose-induced intramuscular adipogenesis in porcine muscle satellite cells. High glucose (25 mM) dramatically increased intracellular lipid accumulation in cells during the 10-day adipogenic differentiation period. The expressions of CCAAT/enhancer binding protein-alpha (C/EBP-alpha) and fatty acid synthase (FAS) protein were gradually enhanced during the 10-day duration while mTOR phosphorylation and sterol-regulatory-element-binding protein (SREBP)-1c protein were induced on day 4. Moreover, inhibition of mTOR activity by rapamycin resulted in a reduction of SREBP-1c protein expression and adipogenesis in cells. Collectively, our findings suggest that the adipogenic differentiation of porcine muscle satellite cells and a succeeding extensive adipogenesis, which is triggered by high glucose, is initiated by the mTOR signal pathway through the activation of SREBP-1c protein. This process is previously uncharacterized and suggests a cellular mechanism may be involved in ectopic lipid deposition in skeletal muscle during type 2 diabetes.
authors.affiliation: State Key Laboratory of Animal Nutrition, College of Animal Science & Technology, China Agricultural University, Beijing 100193, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yue
authors.forename: Jingdong
authors.initials: J
authors.lastname: Yin
authors.forename: Fengna
authors.initials: F
authors.lastname: Li
authors.forename: Defa
authors.initials: D
authors.lastname: Li
authors.forename: Min
authors.initials: M
authors.lastname: Du
mesh_terms: D050156:Adipogenesis; D000818:Animals; D022763:CCAAT-Enhancer-Binding Protein-alpha / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D064429:Fatty Acid Synthases / Q000235:genetics / Q000378:metabolism; D005947:Glucose / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology*; D015398:Signal Transduction; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics / Q000378:metabolism; D013552:Swine; D058570:TOR Serine-Threonine Kinases
chemical_list: D022763:CCAAT-Enhancer-Binding Protein-alpha; D047908:Intracellular Signaling Peptides and Proteins; D051780:Sterol Regulatory Element Binding Protein 1; D064429:Fatty Acid Synthases; D017346:Protein Serine-Threonine Kinases; D058570:TOR Serine-Threonine Kinases; D005947:Glucose