title: Decorin activates Akt downstream of IGF-IR and promotes myoblast differentiation.
abstract: Decorin, a small leucine-rich proteoglycan, plays an important role in cellular activities through modification of growth factors. It also acts as a signaling molecule to non-muscle cells through epidermal growth factor receptor or insulin-like growth factor I receptor (IGF-IR). However, it is unclear if decorin acts as a signaling molecule to myogenic cells. In this study, we investigated the effect of decorin on the differentiation of myoblasts and the signaling via IGF-IR to myogenic cells. C2C12 myoblasts cultured in media containing decorin for 72 h showed more extensive formation of multinucleated myotubes than control cells cultured in the same media without decorin. The protein expressions of myogenin and myosin heavy chian were higher in decorn-treated cells than in control cells. These results suggest that decorin enhances the differentiation of myoblasts. Western blot analysis and immunocytochemistry showed that IGF-IR was expressed in myoblasts and myotubes. Furthermore, Akt, which is downstream of IGF-IR, was more phosphorylated in myoblasts cultured in media containing decorin than those in media without decorin. These results suggest that decorin activates Akt downstream of IGF-IR and enhances the differentiation of myogenic cells.
authors.affiliation: Division of Bioresources and Bioproduction, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Suzuki
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Kishioka
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Wakamatsu
authors.forename: Takanori
authors.initials: T
authors.lastname: Nishimura
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D058575:Decorin / Q000494:pharmacology*; D032446:Myoblasts / Q000166:cytology / Q000187:drug effects*; D017526:Receptor, IGF Type 1 / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D058575:Decorin; D017526:Receptor, IGF Type 1
keywords: Akt; IGF-IR; decorin; myoblast; skeletal muscle