title: Activation of integrin alphaIIbbeta3 expressed in Chinese hamster ovary cells is required for interaction with solid-phase von Willebrand factor.
abstract: Dithiothreitol (DTT) is known to induce an active conformation of alphaIIbbeta3 integrin and to promote the aggregation of Chinese hamster ovary (CHO)-alphaIIbbeta3 cells in the presence of soluble fibrinogen (Fg). The aim of this study was to compare adhesion and spreading with Fg or von Willebrand factor (VWF) of CHO-alphaIIbbeta3 cells in the presence or absence of DTT. Our results indicate that DTT treatment was required to induce cell spreading on VWF. In contrast, CHO-alphaIIbbeta3 cell spreading on Fg was already optimal in the absence of DTT. We used a small perfusion chamber coupled to videomicroscopy to demonstrate that CHO-alphaIIbbeta3 cells that were adherent and spread on VWF required DTT activation to resist to detachment under increasing shear rates (50-1600/s). In contrast, untreated or DTT-treated cells spread on Fg were able to resist to extremely high flow rates. These data provide novel evidence that activated alphaIIbbeta3 is absolutely required for spread cells to resist detachment and strengthens the importance of the alphaIIbbeta3 activation step for adhesion and spreading to VWF.
authors.affiliation: INSERM U143, Hôpital de Bicetre, Bicetre, France, and Laboratoire Franco-Luxembourgeois de Recherche Biomedicale, Luxembourg.
authors.forename: Médina
authors.initials: M
authors.lastname: Mekrache
authors.forename: Paulette
authors.initials: P
authors.lastname: Legendre
authors.forename: Nelly
authors.initials: N
authors.lastname: Kieffer
authors.forename: Dominique
authors.initials: D
authors.lastname: Baruch
mesh_terms: D000818:Animals; D016466:CHO Cells / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002469:Cell Separation / Q000379:methods; D006224:Cricetinae; D015194:Diffusion Chambers, Culture; D004229:Dithiothreitol / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005340:Fibrinogen / Q000378:metabolism; D005434:Flow Cytometry; D039302:Integrin alphaVbeta3 / Q000378:metabolism / Q000502:physiology; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism / Q000502:physiology*; D012212:Rheology; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D039302:Integrin alphaVbeta3; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D014841:von Willebrand Factor; D005340:Fibrinogen; D004229:Dithiothreitol