Ca2+ homeostasis and cytoskeletal rearrangement operated by sphingosine 1-phosphate in C2C12 myoblastic cells
Authors: Francini F., Formigli L., Meacci E., Vassalli M., Nosi D., Quercioli F., Tiribilli B., Bencini C., Squecco R., Bruni P., Orlandini S.Z.
Autors Affiliation: Dept. of Physiological Sciences, University of Florence, Viale G. B. Morgagni, 63, Florence 50134, Italy; Department of Anatomy, University of Florence, Viale G. B. Morgagni, 85, Florence 50134, Italy; Dept. of Biochemical Sciences, University of Florence, Viale G. B. Morgagni, 50, Florence 50134, Italy; Biophotonics Lab, National Institute of Applied Optics, Largo Enrico Fermi, 6, 50125 Florence, Italy
Abstract: In hypogravity conditions unloading of skeletal muscle fibres causes alterations in skeletal muscle structure and functions including growth, gene expression, cell differentiation, cytoskeletal organization, contractility and plasticity. Recent studies have identified sphingosine 1-phosphate (SPP) as a lipid mediator capable of eliciting intracellular Ca2+ transients [1, 2], cell proliferation, differentiation, suppression of apoptosis, as well as cell injury repair . The aim of this research is to evaluate a possible involvement of SPP in skeletal muscle cells differentiation and repair from space-flight damage. Particularly, we investigated the Ca2+ sources and the changes on the cytoskeletal rearrangement induced by SPP in a mouse skeletal (C2C12) myoblastic cell line. Confocal fluorescence imaging revealed that SPP elicited Ca2+ transients which propagated throughout the cytosol and nucleus. This response required extracellular and intracellular Ca2+ mobilization, SPP also induced cell contraction through a Ca2+-independent/Rho-dependent pathway. The nuclear Ca2+ transients are suggestive for an action of SPP in the differentiation program and damage repair.
KeyWords: Antibodies; Cytology; Fluorescence; Growth kinetics; Medical imaging; Musculoskeletal system; Physiology, Cytoskeletal; Homeostasis; Myoblastic cells; Sphingosine phosphate, Cell culture