u-0126 and glycyl-arginyl-glycyl-aspartyl-seryl-proline

In order to determine whether integrin dynamics is associated with intracellular Ca(2+) concentration ([Ca(2+)](i)) mobilization in ECs in response to hemodynamic forces, changes in [Ca(2+)](i) in fluo-4-loaded cultured bovine aortic endothelial cells (BAECs) under fluid flow conditions were visualized employing laser scanning confocal microscopy. Following the onset of flow stimulus, transient increases in [Ca(2+)](i) occurred several times in individual BAECs during the 30-min observation period. The frequency of these [Ca(2+)](i) transients was clearly reduced by the application of an integrin antagonist (GRGDSP peptide). Furthermore, treatment of cells with an integrin activator (Mn(2+)) resulted in reduction of peak [Ca(2+)](i) levels and elevated frequency, which was markedly rescued upon GRGDSP administration. In contrast, an actin de-polymerizing agent (cytochalasin D) exerted no inhibitory effects; rather, cytochalasin D more likely facilitated [Ca(2+)](i) transients. Moreover, [Ca(2+)](i) transients, which were suppressed by short interference RNA-induced silencing of alphav integrin, exhibited greater frequently in cells cultured on vitronectin substratum in comparison with those cultured on fibronectin or collagen substratum. Either removal of extracellular Ca(2+), application of an inhibitor of endoplasmic reticulum Ca(2+)-ATPase (thapsigargin) or non-selective cation channel blocker (La(3+)) inhibited the [Ca(2+)](i) transients. Additionally, [Ca(2+)](i) transients were attenuated by extracellular signal-regulated kinase (ERK) kinase inhibitor (U0126); in contrast, [Ca(2+)](i) transients were unaffected by tyrosine kinase inhibitor (genistein) or phosphatidylinositol 3-kinase (PI3K) inhibitor (LY294002). Therefore, our findings revealed that alphav integrin dynamics modulates the frequency of flow-induced [Ca(2+)](i) transients in BAECs in an ERK-dependent fashion.

Topics: Actins; Animals; Butadienes; Calcium; Cattle; Cell Adhesion; Cells, Cultured; Collagen Type IV; Cytoskeleton; Dose-Response Relationship, Drug; Endothelial Cells; Enzyme Inhibitors; Extracellular Signal-Regulated MAP Kinases; Fibronectins; Integrin alphaV; Manganese; Microscopy, Confocal; Mitogen-Activated Protein Kinase Kinases; Models, Biological; Nitriles; Oligopeptides; Rheology; RNA Interference; Stress, Mechanical; Vitronectin