Shear Stress–Induced Endothelial Cell Migration Involves Integrin Signaling Via the Fibronectin Receptor Subunits α ₅ and β ₁

Abstract

Abstract-Endothelial cell (EC) migration is required for angiogenesis, neovascularization, and reendothelialization.Integrins, known as ␣␤-heterodimeric cell-surface receptors, regulate cell migration and are essential for mechanotransduction of hemodynamic forces. Therefore, we investigated the effect of shear stress on EC migration and the contribution of the integrins and integrin-dependent signaling pathways in a scratched-wound assay. Laminar shear stress-induced EC migration was significantly reduced by integrin-receptor blocking with RGD peptides or with neutralizing antibodies against integrin subunits ␣ 5 and ␤ 1 , whereas antibodies against ␣ v ␤ 3 or ␣ 2 ␤ 1 had no effect. Cell-surface levels of the integrin ␣ 5 and ␤ 1 were specifically upregulated in migrating ECs at the wound edges. Consistent with the important role of integrins for shear stress-increased cell migration, blockade of the integrinassociated adapter protein Shc by overexpression of dominant negative construct inhibited shear stress-stimulated EC migration. Moreover, pharmacological inhibition of the integrin downstream effector signaling molecules ERK1/2 or phosphatidyl-inositol-3-kinase prevented shear stress-induced EC migration. In contrast, inhibition of the NO synthase had no effect. Taken ntegrins are ␣␤-heterodimeric cell-surface receptors that recognize a large number of extracellular ligands. 1-3 Currently, 18 ␣-and 8 ␤-subunits have been identified, which could form more than 24 heterodimeric receptors. 3,4 Ligand binding by integrins regulates such processes as cell adhesion, growth, differentiation, and migration. 1,5 Cell adhesion and migration are required for angiogenesis, which was thought to depend primarily on ␣ v -integrins, for example, ␣ v ␤ 3 . 6 Studies in ␣ v -knockout mice, however, indicate that other receptors and their ligands are also involved in vasculogenesis and angiogenesis. 7 Consistent with these findings, recent knockout studies indicate a more important role of other integrins, such as ␤ 1 or ␣ 5 . 4 ␣ 5 -Knockout mice have severe defects in vascular development, 8 and ␣ 1 ␤ 1 -and ␣ 2 ␤ 1 -integrins seems to contribute to angiogenesis. 9,10 Integrins play a further important role in mediating mechanical stress-induced signals. Specifically, integrins like ␣ 5 ␤ 1 and ␣ v ␤ 3 are essential for the mechanotransduction of hemodynamic forces into biochemical signals. [11][12][13][14][15] Hemodynamic forces are important regulators of blood vessel function and structure. Of these forces, the laminar blood flow (shear stress) is a potent endogenous mediator of atheroprotective signals in endothelial cells (ECs). 14 Several studies have shown that the beneficial effects of shear stress, such as activation of the prosurvival kinases Akt and ERK1/2, require an intact integrin signaling. 12,13,16 We have previously demonstrated that laminar shear stress upregulates the fibronectin receptor subunits ␣ 5 and ␤ 1 in ECs and enhances EC adhesion and survival. 17 In addition, integrins are important for cell m...

Lymphocytes can self-steer passively with wind vane uropods

“…NS, not significant. NATURE COMMUNICATIONS | DOI: 10.1038/ncomms6213 ARTICLE of Dictyostelium discoideum 23 , Entamoeba histolytica 24 and endothelial cells 25 . However, inhibitors of phosphoinositide 3-kinases or G-protein-coupled receptors (Supplementary Note 5 and Supplementary Fig.…”

Mechanotransduction in endothelial cell migration

“…FAK/Src association triggers downstream signaling events such as phosphorylation of p130CAS and extracellular-regulated kinase (ERK) kinase to mediate cell adhesion and migration [Burridge et al, 1992;Chen et al, 1994a;Schlaepfer et al, 1994;Vuori and Ruoslahti, 1995;Zhu and Assoian, 1995;Cary et al, 1998]. Consistently, inhibition of PI-3 kinase and ERK has been shown to decrease EC migration under flow [Urbich et al, 2002]. There is also evidence that FAK can crosstalk with Rho GTPases-mediated signaling.…”

“…Furthermore, shear stress can increase integrin binding affinity for the ECM, as measured by using an antibody that recognizes activated a v b 3 [Tzima et al, 2001]; however, this integrin activation does not show polarized distribution, although the new FAs only form in the flow direction. In addition to post-translational activation of integrins, shear stress increases the expression of integrin a 5 b 1 to enhance cell migration [Urbich et al, 2002].…”

“…In parallel to FAK, adaptor protein Shc can also mediate integrin signaling [Wary et al, 1996]. Shear stress increases the association of integrin and Shc [Chen et al, 1999a;Jalali et al, 2001], and inhibition of Shc decreases shear stress-induced EC migration [Urbich et al, 2002].…”

An integrated microfluidic device for characterizing chondrocyte metabolism in response to distinct levels of fluid flow stimulus

“…Presently, several types of apparatus have been created for inducing fluid shear stress, such as parallel-plate flow chambers (Schinagl et al 1999;Gemmiti and Guldberg 2006), cone and plate viscometers (Urbich et al 2002;Bussolari et al 1982). In these studies, a parallel-plate flow chamber or derivative devices, where a single shear stress is evaluated for a single input flow rate, have been widely used to generate fluid shear stress (Gemmiti and Guldberg 2009).…”