Rosalba Giannini

University of Florence

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Flaminia Chellini

University of Florence

Lucia Polidori

University of Florence

Massimo Vassalli

University of Glasgow

Ferdinando Paternostro

University of Florence

Alessia Tani

University of Florence

Daniele Nosi

University of Florence

W. Pompe

Leipzig University

Elisabetta Meacci

University of Florence

Anke Schnapper

Medizinische Hochschule Hannover

Mario Cannas

Università degli Studi del Piemonte Orientale “Amedeo Avogadro”

Cooperative Institutions

University of Florence

TU Dresden

Universidad Complutense de Madrid

Instituto de Salud Carlos III

Instituto Ramón y Cajal de Investigación Sanitaria

University College London

The Royal Free Hospital

University Hospital Carl Gustav Carus

Instituto de Investigación Sanitaria del Hospital Clínico San Carlos

University of Bologna

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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

Journal of Cell Science (2005)

Lucia Formigli Elisabetta Meacci Chiasa Sassoli Flaminia Chellini Rosalba Giannini

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 alpha- and beta-actin constructs were stimulated with S1P (1 microM) 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.

C2C12

10.1242/jcs.01695

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Neodymium:yttrium aluminum garnet laser irradiation with low pulse energy: a potential tool for the treatment of peri‐implant disease

Clinical Oral Implants Research (2006)

Rosalba Giannini Massimo Vassalli Flaminia Chellini Lucia Polidori Rosanna Dei

Bacterial contamination may seriously compromise successful implant osteointegration in the clinical practice of dental implantology. Several methods for eliminating bacteria from the infected implants have been proposed, but none of them have been shown to be an effective tool in the treatment of peri-implantitis. In the present study, we investigated the efficacy of pulsed neodymium:yttrium aluminum garnet laser irradiation (Nd:YAG) in achieving bacterial ablation while preserving the surface properties of titanium implants. For this purpose, suspensions of Escherichia coli or Actinobacillus (Haemophilus) actinomycetemcomitans were irradiated with different laser parameters, both streaked on titanium implants, and in broth medium. It was found, by light and atomic force microscopy, that Nd:YAG laser, when used with proper working parameters, was able to bring about a consistent microbial ablation of both aerobic and anaerobic species, without damaging the titanium surface.

Neodymium

Laser Ablation

Peri-implantitis

10.1111/j.1600-0501.2006.01278.x

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Effects of S1P on Myoblastic Cell Contraction: Possible Involvement of Ca<sup>2+</sup>-Independent Mechanisms

Cells Tissues Organs (2004)

Daniele Nosi Massimo Vassalli Lucia Polidori Rosalba Giannini Alessia Tani

Sphingosine-1-phosphate (S1P) is a lipid mediator, which affects many essential processes such as cell proliferation, differentiation and contraction in many cell types. We have previously demonstrated that the lipid mediator elicits Ca(2+) transients in a myoblastic cell line (C2C12) by interacting with its specific receptors (S1PR(s)). In the present study, we wanted to correlate the Ca(2+) response with activation of myoblastic cell contractility. C2C12 cells were first investigated for the expression and cellular organization of cytoskeletal proteins by immunoconfocal microscopy. We found that myoblasts exhibited a quite immature cytoskeleton, with filamentous actin dispersed as a web-like structure within the cytoplasm. To evaluate intracellular Ca(2+) mobilization, the cells were loaded with a fluorescent Ca(2+) indicator (Fluo-3), stimulated with S1P and simultaneously observed with differential interference contrast and fluorescence optics. Exogenous S1P-induced myoblastic cell contraction was temporally unrelated to S1P-induced intracellular Ca(2+) increase; cell contraction occurred within 5-8 s from stimulation, whereas intracellular Ca(2+) increase was evident only after 15-25 s. To support the Ca(2+) independence of myoblastic cell contraction, the cells were pretreated with a Ca(2+) chelator, BAPTA/AM, prior to stimulation with S1P. In these experimental conditions, the myoblasts were still able to contract, whereas the S1P-induced Ca(2+) transients were completely abolished. On the contrary, when C2C12 cells were induced to differentiate into skeletal myotubes, they responded to S1P with a rapid cell contraction concurrent with an increase in the intracellular Ca(2+). These data suggest that Ca(2+)-independent mechanism of cell contraction may be replaced by Ca(2+)-dependent ones during skeletal muscle differentiation.

BAPTA

C2C12

Calcium in biology

10.1159/000082243

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Citations (3)

Remembering a leading forest scientist: Ezio Magini

Forest - Rivista di Selvicoltura ed Ecologia Forestale (2020)

Rosalba Giannini

He passed away twenty years ago, but the memory of Prof. Ezio Magini

10.3832/efor0060-017

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