Vasoactive effects of soluble matrix proteins and integrin-binding peptides on arterioles are mediated by a v b 3 and a 5 b 1 integrins. To examine the underlying mechanisms, we measured L-type Ca 2 1 channel current in arteriolar smooth muscle cells in response to integrin ligands. Whole-cell, inward Ba 2 1 currents were inhibited after application of soluble cyclic RGD peptide, vitronectin (VN), fibronectin (FN), either of two anti– b 3 integrin antibodies, or monovalent b 3 antibody. With VN or b 3 antibody coated onto microbeads and presented as an insoluble ligand, current was also inhibited. In contrast, beads coated with FN or a 5 antibody produced significant enhancement of current after bead attachment. Soluble a 5 antibody had no effect on current but blocked the increase in current evoked by FNcoated beads and enhanced current when applied in combination with an appropriate IgG. The data suggest that a v b 3 and a 5 b 1 integrins are differentially linked through intracellular signaling pathways to the L-type Ca 2 1 channel and thereby alter control of Ca 2 1 influx in vascular smooth muscle. This would account for the vasoactive effects of integrin ligands on arterioles and provide a potential mechanism for wound recognition during tissue injury.
Mechanism for laser-induced neovascularization in rat choroid: Accumulation of integrin α chain-positive cells and their ligands
PURPOSE Inhibitors binding to integrins α5 and αv are antiangiogenic in models of choroidal neovascularization (CNV). However, a comprehensive understanding of the accumulation of integrin α isoform-positive cells, their ligands, and associations is limited. The purpose of the present study was to examine the localization of integrin α chain-positive cells and their extracellular matrix (ECM) l...متن کامل
PSGL-1 participates in E-selectin-mediated progenitor homing to bone marrow: evidence for cooperation between E-selectin ligands and alpha4 integrin.
The nature and exact function of selectin ligands involved in hematopoietic progenitor cell (HPC) homing to the bone marrow (BM) are unclear. Using murine progenitor homing assays in lethally irradiated recipients, we found that the P-selectin glycoprotein ligand-1 (PSGL-1) plays a partial role in HPC homing to the BM (a reduction of about 35% when the P-selectin binding region is blocked). Blo...متن کامل
The novel α4B murine α4 integrin protein splicing variant inhibits α4 protein-dependent cell adhesion.
Integrins affect the motility of multiple cell types to control cell survival, growth, or differentiation, which are mediated by cell-cell and cell-extracellular matrix interactions. We reported previously that the α9 integrin splicing variant, SFα9, promotes WT α9 integrin-dependent adhesion. In this study, we introduced a new murine α4 integrin splicing variant, α4B, which has a novel short c...متن کامل
Stem cells respond to the microenvironment (niche) they are located in. Under natural conditions, the extracellular matrix (ECM) is the essential component the in stem cell niche, in which both integrin ligands and growth factors are important regulators to directly or indirectly modulate the cell behavior. In this review, we summarize the current knowledge about the potential of integrin ligan...متن کامل
Expression of a constitutively active R-ras converted two cell lines that grow in suspension into highly adherent cells. There was little change in cell surface expression of integrins, but attachment to surfaces coated with the integrin ligands was greatly enhanced. Cells transfected with activated R-ras bound integrin ligands from solution with higher affinities and assembled severalfold more...متن کامل
Increased extracellular pressure enhances cancer cell integrin-binding affinity through phosphorylation of beta1-integrin at threonine 788/789.
Increased extracellular pressure stimulates beta1-integrin-dependent cancer cell adhesion. We asked whether pressure-induced adhesion is mediated by changes in beta1-integrin binding affinity or avidity and whether these changes are phosphorylation dependent. We evaluated integrin affinity and clustering in human SW620 colon cancer cells by measuring differences in binding between soluble Arg-G...متن کامل