Affiliations: INSERM UMR 651 (ex 492), Fonctions Cellulaires et Moléculaires de l'Appareil Respiratoire et des Vaisseaux, Faculté de Médecine et des Sciences, Université Paris XII - 8, rue du Général Sarrail, 94010 Créteil cedex, France
Note: [] Present address: Duke University Medical Center, 368 Nanaline Duke Building, Research DR, Durham, NC 27710, USA.
Note: [] Present address: Laboratoire de Neuro-Physique Cellulaire, LNPC, UFR Biomédicale, 75 270 Paris cedex 06, France.
Note: [] Corresponding author: Daniel Isabey, Inserm UMR 651, Equipe Biomécanique Cellulaire et Respiratoire, Faculté de Médecine, 8 rue du Général Sarrail, 94010, Creteil cedex, France. Tel.: +33 1 49 81 37 00; Fax number: +33 1 48 98 17 77; E-mail: [email protected].
Abstract: Using Magnetic Twisting Cytometry (MTC) technique, we attempted to characterize in vitro the rigidity of the lining tissue covering the lung alveolar wall from its apical face. We purposely used a cellular model constituted by a monolayer of human alveolar epithelial cell (A549) over which microbeads, fixed to InterCellular Adhesion Molecule (ICAM-1), exert a controlled mechanical stress. ICAM-1 expression was induced by Tumor Necrosis Factor-α (TNF-α). Rigidity measurements, performed in the course of cytochalasin D depolymerization, reveal the force transmitter role of the transmembrane receptor ICAM-1 and demonstrate that ICAM-1 and F-actin linkages confers mechanical rigidity to the apical face of the epithelial cell monolayer resembling that provided by integrins. These results confirm the ability of MTC in identifying transmembrane mechanoreceptors in relation with F-actin. Molecular linkages between ICAM-1 and F-actin were observed by spatial visualisations of the structure after double staining of F-actin and anti ICAM-1 antibody through confocal microscopy.
Keywords: Alveolar epithelial cell line, cell mechanics, F-actin structure, ICAM-1, transient magnetic bead twisting cytometry, migration, adhesion, 3D visualisation, cytoskeleton
