Sphingosine 1-phosphate evokes calcium signals in C2C12 myoblasts via Edg3 and Edg5 receptors

Year: 2002

Authors: Meacci E., Cencetti F., Formigli L., Squecco R., Donati C., Tiribilli B., Quercioli F., Orlandini Zecchi S., Francini Fa., Bruni P.

Autors Affiliation: Dipartimento di Scienze Biochimiche, Università degli Studi di Firenze, Viale GB. Morgagni 50, 50134 Firenze, Italy;
Dipartimento di Anatomia, Istologia e Medicina Legale, Università degli Studi di Firenze, Viale GB. Morgagni 85, 50134 Firenze, Italy;
Dipartimento di Scienze Fisiologiche, Università degli Studi di Firenze, Viale GB. Morgagni 63, 50134 Firenze, Italy;
Istituto Nazionale di Ottica Applicata, Laboratorio di Biofotonica, Viale GB. Morgagni 85, 50134 Firenze, Italy

Abstract: Sphingosine 1-phosphate (SPP) is a bioactive lipid that exerts multiple biological effects in a large variety of cell types, acting as either an intracellular messenger or an extracellular ligand coupled to Edg-family receptors (where Edg stands for endothelial differentiation gene). Here we report that in C2C12 myoblasts SPP elicited significant Call mobilization. Analysis of the process using a confocal laser-scanning microscope showed that the Call response occurred in a high percentage of cells, despite variations in amplitude and kinetics. Quantitative analysis of SPP-induced Ca2+ transients performed with a spectrophoto-fluorimeter showed that the rise in Ca2+ was strictly dependent on availability of extracellular Ca2+. Cell treatment with pertussis toxin partially prevented the Ca2+ response induced by SPP, indicating that G(i)-coupled-receptors were involved. Indeed, SPP action was shown to be mediated by agonist-specific Edg receptors. In particular, suramin, an antagonist of the SPP-specific receptor Edg3, as well as down-regulation of Edg3 by cell transfection with antisense oligodeoxyribonucleotides (ODN), significantly reduced agonist-mediated Ca2+ mobilization. Moreover, an antisense ODN designed to inhibit Edg5 expression also decreased the SPP-induced rise in Ca2+, although to a lesser extent than that observed by inhibiting Edg3. On the contrary, the SPP response was unaffected in myoblasts loaded with antisense ODN specific for Edg1. Remarkably, the concomitant inhibition of Edg3 and Edg5 receptors abolished the SPP-induced Ca2+ increase, supporting the notion that Ca2+ mobilization in C2C12 cells induced by SPP is a receptor-mediated process that involves Edg3 and Edg5, but not Edg1.

Journal/Review: BIOCHEMICAL JOURNAL

Volume: 362      Pages from: 349  to: 357

KeyWords: Calcium; Cells; Lipids; Phosphates, Mobilization; Myoblasts, Biochemistry, antisense oligodeoxynucleotide; calcium ion; Edg3 receptor; Edg5 receptor; receptor protein; sphingosine 1 phosphate; suramin; unclassified drug, animal cell; article; calcium mobilization; gene; genetic transfection; mouse; myoblast; nonhuman; priority journal; quantitative assay; receptor down regulation; spectrofluorometry, Animals; Calcium; Calcium Signaling; Cells, Cultured; DNA-Binding Proteins; Egtazic Acid; Enzyme Inhibitors; I-kappa B Proteins; Kinetics; Lysophospholipids; Muscle, Skeletal; Pertussis Toxin; Protein Kinase C; Receptors, Cell Surface; Receptors, G-Protein-Coupled; Receptors, Lysophospholipid; Sphingosine; Virulence Factors, Bordetella, Animalia
DOI: 10.1042/0264-6021:3620349

Citations: 40
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