title: A role for calcium-calmodulin in regulating nitric oxide production during skeletal muscle satellite cell activation.
abstract: When skeletal muscle is stretched or injured, myogenic satellite cells are activated to enter the cell cycle. This process depends on nitric oxide (NO) production by NO synthase (NOS), matrix metalloproteinase activation, release of hepatocyte growth factor (HGF) from the extracellular matrix, and presentation of HGF to the c-met receptor as demonstrated by a primary culture and in vivo assays. We now add evidence that calcium-calmodulin is involved in the satellite cell activation cascade in vitro. Conditioned medium from cultures that were treated with a calcium ionophore (A23187, ionomycin) for 2 h activated cultured satellite cells and contained active HGF, similar to the effect of mechanical stretch or NO donor treatments. The response was abolished by addition of calmodulin inhibitors (calmidazolium, W-13, W-12) or a NOS inhibitor N(G)-nitro-l-arginine methyl ester hydrochloride but not by its less inactive enantiomer N(G)-nitro-d-arginine methyl ester hydrochloride. Satellite cells were also shown to express functional calmodulin protein having a calcium-binding activity at 12 h postplating, which is the time at which the calcium ionophore was added in this study and the stretch treatment was applied in our previous experiments. Therefore, results from these experiments provide an additional insight that calcium-calmodulin mediates HGF release from the matrix and that this step in the activation pathway is upstream from NO synthesis.
authors.affiliation: Department of Bioscience, Graduate School of Agriculture, Kyushu University, Fukuoka, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Tatsumi
authors.forename: Adam L
authors.initials: AL
authors.lastname: Wuollet
authors.forename: Kuniko
authors.initials: K
authors.lastname: Tabata
authors.forename: Shotaro
authors.initials: S
authors.lastname: Nishimura
authors.forename: Shoji
authors.initials: S
authors.lastname: Tabata
authors.forename: Wataru
authors.initials: W
authors.lastname: Mizunoya
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Ikeuchi
authors.forename: Ronald E
authors.initials: RE
authors.lastname: Allen
mesh_terms: D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017228:Hepatocyte Growth Factor / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D007476:Ionophores / Q000494:pharmacology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D032496:Satellite Cells, Skeletal Muscle / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D002147:Calmodulin; D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D007093:Imidazoles; D007476:Ionophores; D013449:Sulfonamides; D009569:Nitric Oxide; C040184:W 12; D000001:Calcimycin; C031938:calmidazolium; D017228:Hepatocyte Growth Factor; C033772:N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide; D019001:Nitric Oxide Synthase; D002118:Calcium; D019331:NG-Nitroarginine Methyl Ester