Glycosaminoglycan mimetics trigger IP3-dependent intracellular calcium release in myoblasts.
Glycosaminoglycans (GAG) are sulfated polysaccharides that play an important role in regulating cell functions. GAG mimetics called RGTAs (for ReGeneraTing Agents) have been shown to stimulate tissue repair. In particular they accelerate myogenesis, in part via their heparin-mimetic property towards growth factors. RGTAs also increase activity of calcium-dependent intracellular protease suggesting an effect on calcium cellular homeostasis. This effect was presently investigated on myoblasts in vitro using one member of the RGTA family molecule named OTR4120. We have shown that OTR4120 or heparin induced transient increases of intracellular calcium concentration ([Ca(2+)]i) in pre-fusing myoblasts from both mouse SolD7 cell line and rat skeletal muscle satellite cells grown in primary culture by mobilising sarcoplasmic reticulum store. This [Ca(2+)]i was not mediated by ryanodine receptors but instead resulted from stimulation of the Inositol-3 phosphate-phospholipase C activation pathway. OTR4120-induced calcium transient was not mediated through an ATP, nor a tyrosine kinase, nor an acetylcholine receptor but principally through serotonin 5-HT2A receptor. This original finding shows that the GAG mimetic can induce calcium signal through serotonin receptors and the IP3 pathway may be relevant to its ability to favour myoblast differentiation. It supports a novel and unexpected function of GAGs in the regulation of calcium homeostasis.
Martelly
Isabelle
I
Laboratoire de Recherche sur la Croissance Cellulaire, la Réparation et la Régénération Tissulaires (CRRET), UMR 7149-CNRS, Université Paris-Est Créteil, France. martelly@univ-paris12.fr
Singabraya
Dominique
D
Vandebrouck
Aurélie
A
Papy-Garcia
Dulce
D
Cognard
Christian
C
Raymond
Guy
G
Guillet-Deniau
Isabelle
I
Courty
Jose
J
Constantin
Bruno
B
D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002136:Calcium, Dietary / Q000378:metabolism / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002999:Clone Cells; D003593:Cytoplasm / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism / Q000494:pharmacology*; D006493:Heparin / Q000378:metabolism / Q000494:pharmacology; D007295:Inositol Phosphates; D051379:Mice; D024510:Muscle Development / Q000187:drug effects; D032446:Myoblasts / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism; D012038:Regeneration / Q000187:drug effects; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism / Q000494:pharmacology; D032496:Satellite Cells, Skeletal Muscle / Q000166:cytology / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D002136:Calcium, Dietary; D006025:Glycosaminoglycans; D007295:Inositol Phosphates; C533322:OTR4120; D044402:Receptor, Serotonin, 5-HT2A; D019837:Ryanodine Receptor Calcium Release Channel; C052128:inositol 3-phosphate; D006493:Heparin; D002118:Calcium