title: Sphingosine-1-phosphate mediates epidermal growth factor-induced muscle satellite cell activation.
abstract: Skeletal muscle can regenerate repeatedly due to the presence of resident stem cells, called satellite cells. Because satellite cells are usually quiescent, they must be activated before participating in muscle regeneration in response to stimuli such as injury, overloading, and stretch. Although satellite cell activation is a crucial step in muscle regeneration, little is known of the molecular mechanisms controlling this process. Recent work showed that the bioactive lipid sphingosine-1-phosphate (S1P) plays crucial roles in the activation, proliferation, and differentiation of muscle satellite cells. We investigated the role of growth factors in S1P-mediated satellite cell activation. We found that epidermal growth factor (EGF) in combination with insulin induced proliferation of quiescent undifferentiated mouse myoblast C2C12 cells, which are also known as reserve cells, in serum-free conditions. Sphingosine kinase activity increased when reserve cells were stimulated with EGF. Treatment of reserve cells with the D-erythro-N,N-dimethylsphingosine, Sphingosine Kinase Inhibitor, or siRNA duplexes specific for sphingosine kinase 1, suppressed EGF-induced C2C12 activation. We also present the evidence showing the S1P receptor S1P2 is involved in EGF-induced reserve cell activation. Moreover, we demonstrated a combination of insulin and EGF promoted activation of satellite cells on single myofibers in a manner dependent on SPHK and S1P2. Taken together, our observations show that EGF-induced satellite cell activation is mediated by S1P and its receptor.
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan. Electronic address: cynagata@mail.ecc.u-tokyo.ac.jp.
authors: Yosuke
authors: Y
authors: Nagata
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Kazuya
authors: K
authors: Ohashi
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Eiji
authors: E
authors: Wada
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Yuki
authors: Y
authors: Yuasa
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Masataka
authors: M
authors: Shiozuka
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Yoshiaki
authors: Y
authors: Nonomura
authors: Department of Life Sciences, University of Tokyo, Rm. 15-312, 3-8-1 Komaba, Meguro, Tokyo 153-8902, Japan.
authors: Ryoichi
authors: R
authors: Matsuda
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation; D002478:Cells, Cultured; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D008246:Lysophospholipids / Q000494:pharmacology*; D051379:Mice; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology* / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000099157:Sphingosine Kinase
chemical_list: D004815:Epidermal Growth Factor; D008246:Lysophospholipids; D017853:Phosphotransferases (Alcohol Group Acceptor); D012333:RNA, Messenger; D034741:RNA, Small Interfering; D049349:Receptors, Lysosphingolipid; D013110:Sphingosine; D000099157:Sphingosine Kinase; C060506:sphingosine 1-phosphate
keywords: C2C12; Epidermal growth factor; Reserve cells; Satellite cells; Skeletal muscle; Sphingosine-1-phosphate