title: Fibroblast growth factor inducible 14 (Fn14) is required for the expression of myogenic regulatory factors and differentiation of myoblasts into myotubes. Evidence for TWEAK-independent functions of Fn14 during myogenesis.
abstract: Fibroblast growth factor-inducible 14 (Fn14), distantly related to tumor necrosis factor receptor superfamily and a receptor for TWEAK cytokine, has been implicated in several biological responses. In this study, we have investigated the role of Fn14 in skeletal muscle formation in vitro. Flow cytometric and Western blot analysis revealed that Fn14 is highly expressed on myoblastic cell line C2C12 and mouse primary myoblasts. The expression of Fn14 was decreased upon differentiation of myoblasts into myotubes. Suppression of Fn14 expression using RNA interference inhibited the myotube formation in both C2C12 and primary myoblast cultures. Fn14 was required for the transactivation of skeletal alpha-actin promoter and the expression of specific muscle proteins such as myosin heavy chain fast type and creatine kinase. RNA interference-mediated knockdown of Fn14 receptor in C2C12 myoblasts decreased the levels of myogenic regulatory factors MyoD and myogenin upon induction of differentiation. Conversely, overexpression of MyoD increased differentiation in Fn14-knockdown C2C12 cultures. Suppression of Fn14 expression in C2C12 myoblasts also inhibited the differentiation-associated increase in the activity of serum response factor and RhoA GTPase. In addition, our data suggest that the role of Fn14 during myogenic differentiation could be independent of TWEAK cytokine. Collectively, our study suggests that the Fn14 receptor is required for the expression of myogenic regulatory factors and differentiation of myoblasts into myotubes.
authors: Jerry L. Pettis Memorial Veterans Affairs Medical Center, Loma Linda, California 92357, USA.
authors: Charu
authors: C
authors: Dogra
authors: Susan L
authors: SL
authors: Hall
authors: Nia
authors: N
authors: Wedhas
authors: Thomas A
authors: TA
authors: Linkhart
authors: Ashok
authors: A
authors: Kumar
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D000074049:Cytokine TWEAK; D006801:Humans; D051379:Mice; D024510:Muscle Development / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics / Q000378:metabolism*; D026362:Serum Response Factor / Q000378:metabolism; D000074050:TWEAK Receptor; D048069:Tumor Necrosis Factors / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D000074049:Cytokine TWEAK; D009124:Muscle Proteins; D034741:RNA, Small Interfering; D018124:Receptors, Tumor Necrosis Factor; D026362:Serum Response Factor; C000613297:TNFRSF12A protein, human; C109743:TNFSF12 protein, human; D000074050:TWEAK Receptor; C000613299:Tnfrsf12a protein, mouse; C491645:Tnfsf12 protein, mouse; D048069:Tumor Necrosis Factors; D020742:rhoA GTP-Binding Protein