title: Versican processing by a disintegrin-like and metalloproteinase domain with thrombospondin-1 repeats proteinases-5 and -15 facilitates myoblast fusion.
abstract: Skeletal muscle development and regeneration requires the fusion of myoblasts into multinucleated myotubes. Because the enzymatic proteolysis of a hyaluronan and versican-rich matrix by ADAMTS versicanases is required for developmental morphogenesis, we hypothesized that the clearance of versican may facilitate the fusion of myoblasts during myogenesis. Here, we used transgenic mice and an in vitro model of myoblast fusion, C2C12 cells, to determine a potential role for ADAMTS versicanases. Versican processing was observed during in vivo myogenesis at the time when myoblasts were fusing to form multinucleated myotubes. Relevant ADAMTS genes, chief among them Adamts5 and Adamts15, were expressed both in developing embryonic muscle and differentiating C2C12 cells. Reducing the levels of Adamts5 mRNA in vitro impaired myoblast fusion, which could be rescued with catalytically active but not the inactive forms of ADAMTS5 or ADAMTS15. The addition of inactive ADAMTS5, ADAMTS15, or full-length V1 versican effectively impaired myoblast fusion. Finally, the expansion of a hyaluronan and versican-rich matrix was observed upon reducing the levels of Adamts5 mRNA in myoblasts. These data indicate that these ADAMTS proteinases contribute to the formation of multinucleated myotubes such as is necessary for both skeletal muscle development and during regeneration, by remodeling a versican-rich pericellular matrix of myoblasts. Our study identifies a possible pathway to target for the improvement of myogenesis in a plethora of diseases including cancer cachexia, sarcopenia, and muscular dystrophy.
authors.affiliation: School of Medicine and Molecular and Medical Research SRC, Deakin University, Geelong, Victoria 3216, Australia.
authors.forename: Nicole
authors.initials: N
authors.lastname: Stupka
authors.forename: Christopher
authors.initials: C
authors.lastname: Kintakas
authors.forename: Jason D
authors.initials: JD
authors.lastname: White
authors.forename: Fiona W
authors.initials: FW
authors.lastname: Fraser
authors.forename: Michael
authors.initials: M
authors.lastname: Hanciu
authors.forename: Noriko
authors.initials: N
authors.lastname: Aramaki-Hattori
authors.forename: Sheree
authors.initials: S
authors.lastname: Martin
authors.forename: Chantal
authors.initials: C
authors.lastname: Coles
authors.forename: Fiona
authors.initials: F
authors.lastname: Collier
authors.forename: Alister C
authors.initials: AC
authors.lastname: Ward
authors.forename: Suneel S
authors.initials: SS
authors.lastname: Apte
authors.forename: Daniel R
authors.initials: DR
authors.lastname: McCulloch
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism*; D000071096:ADAMTS Proteins; D000071116:ADAMTS5 Protein; D000818:Animals; D002450:Cell Communication; D002454:Cell Differentiation; D002459:Cell Fusion; D002478:Cells, Cultured; D004622:Embryo, Mammalian; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D024510:Muscle Development; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D032446:Myoblasts / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000096:biosynthesis; D012038:Regeneration; D019699:Thrombospondins / Q000737:chemistry; D053675:Versicans / Q000378:metabolism*
chemical_list: C486779:ADAMTSL4 protein, human; D012333:RNA, Messenger; D019699:Thrombospondins; D053675:Versicans; D051722:ADAM Proteins; D000071096:ADAMTS Proteins; C500267:ADAMTS15 protein, human; D000071116:ADAMTS5 Protein; C498489:Adamts5 protein, mouse