Sphingosine 1-phosphate induces Ca2+ transients and cytoskeletal rearrangement in C2C12 myoblastic cells

Year: 2002

Authors: Formigli L., Francini F., Meacci E., Vassalli M., Nosi D., Quercioli F., Tiribilli B., Bencini C., Piperio C., Bruni P., Orlandini S.Z.

Autors Affiliation: Department of Anatomy, Histology, and Forensic Medicine, University of Florence, 50125 Florence, Italy; Department of Physiological Sciences, University of Florence, 50125 Florence, Italy; Department of Biochemical Sciences, University of Florence, 50134 Florence, Italy; Biophotonics Lab., National Institute of Applied Optics, 50125 Florence, Italy

Abstract: In many cell systems, sphingosine 1-phosphate (SPP) increases cytosolic Ca2+ concentration ([Ca2+](i)) by acting as intracellular mediator and extracellular ligand. We recently demonstrated (Meacci E, Cencetti F, Formigli L, Squecco R, Donati C, Tiribilli B, Quercioli F, Zecchi-Orlandini S, Francini F, and Bruni P. Biochem J 362: 349-357, 2002) involvement of endothelial differentiation gene (Edg) receptors (Rs) specific for SPP in agonist-mediated Ca2+ response of a mouse skeletal myoblastic (C2C12) cell line. Here, we investigated the Ca2+ sources of SPP-mediated Ca2+ transients in C2C12 cells and the possible correlation of ion response to cytoskeletal rearrangement. Confocal fluorescence imaging of C2C12 cells preloaded with Ca2+ dye fluo 3 revealed that SPP elicited a transient Ca2+ increase propagating as a wave throughout the cell. This response required extracellular and intracellular Ca2+ pool mobilization. Indeed, it was significantly reduced by removal of external Ca2+, pretreatment with nifedipine (blocker of L-type plasma membrane Ca2+ channels), and inositol 1,4,5-trisphosphate [Ins(1,4,5)P-3]-mediated Ca2+ pathway inhibitors. Involvement of EdgRs was tested with suramin (specific inhibitor of Edg-3). Fluorescence associated with Ins(1,4,5)P(3)Rs and L-type Ca2+ channels was evident in C2C12 cells. SPP also induced C2C12 cell contraction. This event, however, was unrelated to [Ca2+](i) increase, because the two phenomena were temporally shifted. We propose that SPP may promote C2C12 cell contraction through Ca2+ independent mechanisms.

Journal/Review: AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY

Volume: 282 (6)      Pages from: C1361  to: C1373

KeyWords: calcium channel L type; calcium ion; inositol 1,4,5 trisphosphate; sphingosine 1 phosphate, animal cell; article; calcium cell level; calcium transport; cell line; controlled study; cytoskeleton; fluorescence; mouse; muscle fiber contraction; myoblast; nonhuman; priority journal, Aniline Compounds; Animals; Caffeine; Calcium; Calcium Channel Blockers; Calcium Channels, L-Type; Calcium Signaling; Cell Line; Cytoskeleton; Diglycerides; DNA-Binding Proteins; Extracellular Space; Fluorescent Dyes; I-kappa B Proteins; Inositol 1,4,5-Trisphosphate; Intracellular Fluid; Lysophospholipids; Mice; Microscopy, Confocal; Muscle Contraction; Muscle, Skeletal; Potassium; Receptors, Lysophospholipid; Ryanodine Receptor Calcium Release Channel; Signal Transduction; Sphingosine; Suramin; Xanthenes, Animalia
DOI: 10.1152/ajpcell.00378.2001

Citations: 32
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