title: Transforming growth factor-beta1 upregulates myostatin expression in mouse C2C12 myoblasts.
abstract: Myostatin (MSTN) and transforming growth factor-beta1 (TGF-beta1) belong to the same TGF-beta superfamily of proteins. They are involved in regulation of skeletal muscle growth and development as well as muscle catabolism. The aim of the present study was to investigate the relationship between MSTN and TGF-beta1 expression in proliferating and differentiating mouse C2C12 myoblasts cultured in normal and catabolic conditions and to evaluate the effect of exogenous TGF-beta1 as well as "knock down" of TGF-beta1 receptor type II on MSTN expression in proliferating and differentiating myogenic cells. The direct effect of TGF-beta1 on myostatin was also examined. Myostatin expression increased gradually with cell confluency in proliferating cultures, while the level of TGF-beta1, detected in the form of a 100 kDa small latent complex diminished. Myostatin expression was accompanied by a partial cell cycle arrest. Three forms of myostatin were found: a 52 kDa precursor, a 40 kDa latency associated propeptide, and a 26 kDa active peptide. A decrease in myostatin and TGF-beta1 levels was observed during the first three days of differentiation, which was subsequently followed by significant increase of their expression during next three to four days of differentiation. Catabolic state induced by dexamethasone significantly increased the level of all forms of myostatin as well as latent (100 kDa) and active (25 kDa) forms of TGF-beta1 in differentiating myoblasts in a dose dependent manner. Exogenous TGF-beta1 (2 ng/ml) significantly increased myostatin levels both in proliferating and differentiating C2C12 myoblasts, whereas silencing of the TGF-beta1 receptor II gene significantly lowered myostatin level in examined cells. The presented results indicate that TGF-beta1 may control myostatin-related regulation of myogenesis through up-regulation of myostatin, predominantly in the course of terminal differentiation and glucocorticoid-dependent catabolic stimulation.
authors.affiliation: Department of Physiological Sciences, Faculty of Veterinary Medicine, Warsaw Agricultural University, Warsaw, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Budasz-Rwiderska
authors.forename: M
authors.initials: M
authors.lastname: Jank
authors.forename: T
authors.initials: T
authors.lastname: Motyl
mesh_terms: D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005938:Glucocorticoids / Q000494:pharmacology; D051379:Mice; D008970:Molecular Weight; D024510:Muscle Development / Q000187:drug effects; D032446:Myoblasts / Q000187:drug effects / Q000378:metabolism*; D055435:Myostatin; D020033:Protein Isoforms / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000737:chemistry / Q000378:metabolism*; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: D005938:Glucocorticoids; C525912:Mstn protein, mouse; D055435:Myostatin; D020033:Protein Isoforms; D034741:RNA, Small Interfering; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003907:Dexamethasone; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II