Receptor‐mediated activation of phospholipase D by sphingosine 1‐phosphate in skeletal muscle C2C12 cells

Meacci, Elisabetta; Vasta, Valeria; Donati, Chiara; Farnararo, Marta; Bruni, Paola

doi:10.1016/s0014-5793(99)01033-9

Cited by 50 publications

(65 citation statements)

References 28 publications

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“…Interestingly, we also found that inactivation of Gidependent signalling by PTx also seriously affected the increased ion current and conductance through SACs. These findings are in agreement with our previous observations that PLD activation in myoblasts occurs through Gi-coupled receptor mechanisms (Meacci et al, 1999a), and suggest novel mechanisms of SAC modulation. Given that PLD activation alters cortical actin dynamics (Colley et al, 1997;Platek et al, 2004), it may be speculated that PLD-dependent pathways play a pivotal role in regulating SAC activity by not only contributing to stress fibre formation but also by affecting the peripheral cytoskeletal assembly, which is probably necessary for transducing the mechanical tension to the plasma membrane.…”

Section: Discussionsupporting

confidence: 93%

“…It is also likely that other Rho effector pathways, including mDia and ERM proteins, might contribute to the cytoskeletal response to S1P by favouring accumulation of polymerized actin (Sah et al, 2000). The role of PLD activation in actin rearrangement by S1P is in agreement with our previous observations that S1P elicits PLD activation in the C2C12 myoblasts (Meacci et al, 1999a) and with the requirement for Rho in the regulation of PLD activity by S1P (Meacci et al, 2001). Moreover, previous studies have reported the involvement of PLD in S1P-and lysophosphatidic acid-induced stress fibre formation in other cell types (Porcelli et al, 2002).…”

Section: Discussionsupporting

confidence: 91%

“…Moreover, stress fibre formation by S1P might also be dependent on the activation of phospholipase D (PLD) and, consistently, a direct role for this enzyme in actin bundling has been proposed (Kam and Exton, 2001;Porcelli et al, 2002). In this connection, although its physiological role has not been explored as yet, we have previously demonstrated that both PLD isoforms, PLD1 and PLD2, are expressed and activated in response to exogenous S1P in C2C12 myoblasts (Meacci et al, 1999a). Subsequently, we have shown in the same cells that the bioactive lipid is also capable of enhancing the levels of myosin light chain phosphorylation and increasing myoblastic contractility through Ca 2+ -independent/Rhodependent pathways Formigli et al, 2004).…”

Section: Introductionmentioning

confidence: 95%

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Sphingosine 1-phosphate induces cytoskeletal reorganization in C2C12 myoblasts: physiological relevance for stress fibres in the modulation of ion current through stretch-activated channels

Formigli¹,

Meacci²,

Sassoli³

et al. 2005

Journal of Cell Science

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Sphingosine 1-phosphate (S1P) is a bioactive lipid that is abundantly present in the serum and mediates multiple biological responses. With the aim of extending our knowledge on the role played by S1P in the regulation of cytoskeletal reorganization, native as well as C2C12 myoblasts stably transfected with green fluorescent protein (GFP)-tagged α- and β-actin constructs were stimulated with S1P (1 μM) and observed under confocal and multiphoton microscopes. The addition of S1P induced the appearance of actin stress fibres and focal adhesions through Rho- and phospholipase D (PLD)-mediated pathways. The cytoskeletal response was dependent on the extracellular action of S1P through its specific surface receptors, since the intracellular delivery of the sphingolipid by microinjection was unable to modify the actin cytoskeletal assembly. Interestingly, it was revealed by whole-cell patch-clamp that S1P-induced stress fibre formation was associated with increased ion currents and conductance through stretch-activated channels (SACs), thereby suggesting a possible regulatory role for organized actin in channel sensitivity. Experiments aimed at stretching the plasma membrane of C2C12 cells, using the cantilever of an atomic force microscope, indicated that there was a Ca2+ influx through putative SACs. In conclusion, the present data suggest novel mechanisms of S1P signalling involving actin cytoskeletal reorganization and Ca2+ elevation through SACs that might influence myoblastic functions.

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Section: Discussionsupporting

confidence: 93%

Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 95%

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Sphingosine 1-phosphate induces cytoskeletal reorganization in C2C12 myoblasts: physiological relevance for stress fibres in the modulation of ion current through stretch-activated channels

Formigli¹,

Meacci²,

Sassoli³

et al. 2005

Journal of Cell Science

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“…Murine C2C12 skeletal myoblasts obtained from American Type Culture Collection (ATCC, Manassas, VA), were routinely grown in 100 mm dishes in Dulbecco's modified Eagle's medium (DMEM) and cultured as previously reported (Formigli et al, 2005;Meacci et al, 1999). In some experiments the cells were treated for 30 minutes with the following reagents: S1P, 1 μM, Calbiochem, La Jolla, CA); methyl-β-cyclodextrin (MβCD, 2 mM, Sigma, Milan, Italy) to deplete cell membrane cholesterol; and dihydrocytochalasin B (DHCB 1 μg/ml, Sigma) to inhibit actin polymerization.…”

Section: Cell Cultures and Treatmentsmentioning

confidence: 99%

“…An important sphingolipid metabolite is sphingosine 1-phosphate (S1P), which mainly acts through Gprotein-coupled receptors present on mammalian cells, thereby regulating numerous cell functions, including cell proliferation, differentiation and apoptosis (Zeidan and Hannun, 2007). In the last few years, most of the studies of our group have been focused on the role played in skeletal muscle cell biology by S1P, as a modulator of intracellular Ca 2+ mobilization, phosphatidic acid synthesis and phospholipid remodelling in skeletal muscle cells (Bencini et al, 2003;Donati et al, 2005;Formigli et al, 2002;Meacci et al, 1999;Meacci et al, 2002a;Meacci et al, 2002b). Recently, we have underscored the physiological relevance of the sphingosine-kinase-S1P axis in C2C12 cell growth arrest and differentiation and identified the essential steps of the pro-myogenic action of S1P in skeletal myoblasts, including formation of SFs, upregulation of connexin 43 protein and its interaction with cortical actin (Formigli et al, 2007b;Squecco et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Regulation of transient receptor potential canonical channel 1 (TRPC1) by sphingosine 1-phosphate in C2C12 myoblasts and its relevance for a role of mechanotransduction in skeletal muscle differentiation

Formigli

Sassoli

Squecco

et al. 2009

Journal of Cell Science

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106

108

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Transient receptor potential canonical (TRPC) channels provide cation and Ca2+ entry pathways, which have important regulatory roles in many physio-pathological processes, including muscle dystrophy. However, the mechanisms of activation of these channels remain poorly understood. Using siRNA, we provide the first experimental evidence that TRPC channel 1 (TRPC1), besides acting as a store-operated channel, represents an essential component of stretch-activated channels in C2C12 skeletal myoblasts, as assayed by whole-cell patch-clamp and atomic force microscopic pulling. The channel's activity and stretch-induced Ca2+ influx were modulated by sphingosine 1-phosphate (S1P), a bioactive lipid involved in satellite cell biology and tissue regeneration. We also found that TRPC1 was functionally assembled in lipid rafts, as shown by the fact that cholesterol depletion resulted in the reduction of transmembrane ion current and conductance. Association between TRPC1 and lipid rafts was increased by formation of stress fibres, which was elicited by S1P and abolished by treatment with the actin-disrupting dihydrocytochalasin B, suggesting a role for cytoskeleton in TRPC1 membrane recruitment. Moreover, TRPC1 expression was significantly upregulated during myogenesis, especially in the presence of S1P, implicating a crucial role for TRPC1 in myoblast differentiation. Collectively, these findings may offer new tools for understanding the role of TRPC1 and sphingolipid signalling in skeletal muscle regeneration and provide new therapeutic approaches for skeletal muscle disorders.

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Sphingosine 1‐phosphate induces cell contraction via calcium‐independent/Rho‐dependent pathways in undifferentiated skeletal muscle cells

Formigli

Meacci²,

Vassalli

et al. 2003

Journal Cellular Physiology

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We have previously shown that sphingosine 1-phosphate (S1P) can induce intracellular Ca(2+) mobilization and cell contraction in C2C12 myoblasts and that the two phenomena are temporally unrelated. Although Ca(2+)-independent mechanisms of cell contraction have been the focus of numerous studies on Ca(2+) sensitization of smooth muscle, comparatively less studies have focused on the role that these mechanisms play in the regulation of skeletal muscle contractility. Phosphorylation and activation of myosin by Rho-dependent kinase mediate most of Ca(2+)-independent contractile responses. In the present study, we examined the potential role of Rho/Rho-kinase cascade activation in S1P-induced C2C12 cell contraction. First, we showed that depletion of Ca(2+), by pre-treatment with BAPTA, did not affect S1P-induced myoblastic contractility, whereas it abolished S1P-induced Ca(2+) transients. These results correlated with the absence of troponin C and with the immature cytoskeletal organization of these cells. Experimental evidence demonstrating the involvement of Rho pathway in S1P-stimulated myoblast contraction included: the activation/translocation of RhoA to the membrane in response to agonist-stimulation in cells depleted of Ca(2+) and the inhibition of dynamic changes of the actin cytoskeleton in cells where Rho functions had been inhibited either by overexpression of RhoGDI, a physiological inhibitor of GDP dissociation from Rho proteins, or by pretreatment with Y-27632, a specific Rho kinase inhibitor. Contribution of protein kinase C in this cytoskeletal rearrangement was also evaluated. However, the pretreatment with Gö6976 or rottlerin, specific inhibitors of PKC alpha and PKC delta, respectively, failed to inhibit the agonist-induced myoblastic contraction. Single particle tracking of G-actin fluorescent probe was performed to statistically evaluate actin cytoskeletal dynamics in response to S1P. Stimulation with S1P was also able to increase the phosphorylation level of myosin light chain II. In conclusion, our results strongly suggest that Ca(2+)-independent/Rho-Rho kinase-dependent pathways may exert an important role in S1P-induced myoblastic cell contraction.

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Receptor‐mediated activation of phospholipase D by sphingosine 1‐phosphate in skeletal muscle C2C12 cells

Cited by 50 publications

References 28 publications

Sphingosine 1-phosphate induces cytoskeletal reorganization in C2C12 myoblasts: physiological relevance for stress fibres in the modulation of ion current through stretch-activated channels

Sphingosine 1-phosphate induces cytoskeletal reorganization in C2C12 myoblasts: physiological relevance for stress fibres in the modulation of ion current through stretch-activated channels

Regulation of transient receptor potential canonical channel 1 (TRPC1) by sphingosine 1-phosphate in C2C12 myoblasts and its relevance for a role of mechanotransduction in skeletal muscle differentiation

Sphingosine 1‐phosphate induces cell contraction via calcium‐independent/Rho‐dependent pathways in undifferentiated skeletal muscle cells

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