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Gierow JP, Andersson S, Sjögren EC. Presence of alpha-and beta-integrin subunits in rabbit lacrimal gland acinar cells cultured on a laminin-rich matrix. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 506:59-63. [PMID: 12613889 DOI: 10.1007/978-1-4615-0717-8_7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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252
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Diaz-Araya G, Borg TK, Lavandero S, Loftis MJ, Carver W. IGF-1 modulation of rat cardiac fibroblast behavior and gene expression is age-dependent. CELL COMMUNICATION & ADHESION 2003; 10:155-65. [PMID: 14668062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
The collagenous extracellular matrix (ECM) forms a stress-tolerant network that is essential for proper function of the vertebrate heart. Profound changes have been detected in the interstitial ECM concurrent with developmental and disease processes of the heart. These alterations in either the organization or accumulation of ECM components markedly affect myocardial function. Studies have shown that a number of biochemical factors, including angiotensin II, transforming growth factor-beta, and insulin-like growth factors, modulate collagen expression by heart fibroblasts, however, few studies have examined the differential effects of these factors on fibroblasts from animals of different physiological backgrounds. The present studies were carried out to determine whether cardiac fibroblasts isolated from different aged animals (fetal, neonatal, and adult) have diverse responses to insulin-like growth factor-1 (IGF-1). Fibroblasts isolated from fetal, neonatal, and adult rat hearts were treated with IGF-1, and several downstream responses were measured, including collagen gel contraction, adhesion to ECM, and expression of interstitial collagen and integrins. IGF-1 affected these parameters to different degrees, depending on the age of the animal from which the fibroblasts were isolated. These experiments indicate that IGF-1 is a potent modulator of fibroblast behavior in general; however, significant differences are apparent in the responsiveness of cells to this growth factor depending on the age of the animal of origin. Future experiments will be directed at determining how the in vivo chemical and biomechanical environment affects the response of heart fibroblasts to growth factors such as IGF-1.
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Hilden TJ, Valmu L, Kärkkäinen S, Gahmberg CG. Threonine phosphorylation sites in the beta 2 and beta 7 leukocyte integrin polypeptides. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2003; 170:4170-7. [PMID: 12682249 DOI: 10.4049/jimmunol.170.8.4170] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The cytoplasmic domains of integrins play a key role in a variety of integrin-mediated events including adhesion, migration, and signaling. The molecular mechanisms that enhance integrin function are still incompletely understood. Because protein kinases are known to be involved in the signaling and the activation of integrins, the role of phosphorylation has been studied by several groups. The beta(2) leukocyte integrin subunit has previously been shown to become phosphorylated in leukocytes on cytoplasmic serine and functionally important threonine residues. We have now mapped the phosphorylated threonine residues in activated T cells. After phorbol ester stimulation, all three threonine residues (758-760) of the threonine triplet became phosphorylated but only two at a time. CD3 stimulation leads to a strong threonine phosphorylation of the beta(2) integrin, but differed from phorbol ester activation in that phosphorylation occurred only on threonine 758. The other leukocyte-specific integrin, beta(7), has also been shown to need the cytoplasmic domain and leukocyte-specific signal transduction elements for integrin activation. Cell activation with phorbol ester, and interestingly, through the TCR-CD3 complex, caused beta(7) integrin binding to VCAM-1. Additionally, cell activation led to increased phosphorylation of the beta(7) subunit, and phosphoamino acid analysis revealed that threonine residues became phosphorylated after cell activation. Sequence analysis by manual radiosequencing by Edman degradation established that threonine phosphorylation occurred in the same threonine triplet as in beta(2) phosphorylation.
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Abe E, Matsubara K, Ochi H, Ito M, Oka K, Kameda K. Elevated levels of adhesion molecules derived from leukocytes and endothelial cells in patients with pregnancy-induced hypertension. Hypertens Pregnancy 2003; 22:31-43. [PMID: 12648441 DOI: 10.1081/prg-120016793] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
OBJECTIVE Our purpose was to elucidate the role of adhesion molecules in the pathogenesis of pregnancy-induced hypertension (PIH). METHODS Sera, peripheral lymphocytes, and polymorphonuclear cells (PMN) from PIH patients, normal pregnant women, and nonpregnant women were collected. Soluble intercellular adhesion molecule-1 (sICAM-1) in sera was measured by ELISA. ICAM-1 expression on endothelial cells (EC) incubated with sera was analyzed by flow cytometry and RT-PCR. CD11a, CD11b, and CD18 expression on lymphocytes and PMN were also measured by flow cytometory. RESULTS CD11a and CD18 expression levels on PMN and lymphocytes of PIH patients were significantly higher than those of normal pregnant women (p<0.05). The expression of CD11b was significantly increased in normal pregnancy compared with that in nonpregnant women (p<0.05). Serum sICAM-1 in PIH patients was higher than that in normal pregnant women (p<0.05). ICAM-1 expression level on EC incubated with PIH serum for 24 hr was significantly higher than that with normal pregnant serum (p<0.0005). ICAM-1 mRNA expression after 12-hr incubation with PIH serum was also significantly increased compared with serum from normal pregnant women (p<0.05). CONCLUSION Adhesion molecules may play an important role in the pathogenesis of PIH.
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Albuquerque MLC, Flozak AS. Lamellipodial motility in wounded endothelial cells exposed to physiologic flow is associated with different patterns of beta1-integrin and vinculin localization. J Cell Physiol 2003; 195:50-60. [PMID: 12599208 DOI: 10.1002/jcp.10228] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Integrins- and cytoskeletal-associated focal adhesion proteins may participate in the process of endothelial wound closure, but their relationship in these wounds and in the presence of shear forces has not been defined. The goal in this study was to test the hypotheses that (1) modulation of beta(1)-integrin in human coronary artery endothelial cells (HCAEC) would alter endothelial wound closure under shear stress, and (2) beta(1)-integrin association with vinculin would be necessary for mediating this closure. HCAEC monolayers were pre-conditioned to attain alignment by shearing at 12 dynes/cm(2) for 18 h in a parallel-plate flow chamber. Subsequently, they were divided into three groups: (a) control, (b) treated with anti-beta(1)-integrin adhesion blocking antibody, or (c) treated with anti-beta(1)-integrin adhesion promoting antibody. Next, the monolayers were wounded with a metal spatula, and re-sheared at 20 dynes/cm(2) or left static. Time-lapse imaging and deconvolution microscopy were then performed for 3 h. Immunocytochemistry for beta(1)-integrin expression and vinculin was performed on all wounded monolayers. Under shear stress, vinculin localized to the ends of stress fibers, while beta(1)-integrin took on an intracellular macroaggregate appearance. Treatment with anti-beta(1)-integrin adhesion blocking antibody enhanced wound closure, left the vinculin staining at the lamellipodial tips unchanged, but was associated with beta(1)-integrin staining at the lateral cell edges. Treatment with the anti-beta(1)-integrin adhesion promoting antibody retarded wound closure, increased vinculin staining at cell-cell junctions, and was associated with a fibrillar pattern of beta(1)-integrin staining. Modulation of beta(1)-integrin and changes in beta(1)-integrin and vinculin localization may further our understanding of laminar shear stress-induced endothelial repair in the coronary circulation.
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Wada J, Kanwar YS, Makino H. Relevance of extracellular matrix and its receptors in mammalian nephrogenesis revealed by metanephric organ culture system. Nephrol Dial Transplant 2003; 17 Suppl 9:75-7. [PMID: 12386297 DOI: 10.1093/ndt/17.suppl_9.75] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mammalian nephrogenesis is modulated by a number of extracellular matrix (ECM) glycoproteins, integrins and cell adhesion molecules. We demonstrated the existence of integrins alphavbeta1, alphavbeta3, alphavbeta5 and alphavbeta6 in epithelial elements of developing nephrons. Fibrillin-1 is a putative ligand for integrin alphavbeta3, and tubulointerstitial nephritis antigen (TIN-ag) is a ligand for integrins alphavbeta3 and alpha3beta1. Fibrillin-1 and TIN-ag are also differentially expressed in the developing kidney. The inclusion of antisense oligonucleotide in a mouse kidney organ culture system indicated that the alphav-related integrins and their ligands play an important role in mammalian nephrogenesis. Recently identified modulators of cell-matrix interactions, i.e. beta-galactoside-binding mammalian lectins (galectins), are involved in cell-cell and cell-matrix interactions by cross-linking glycoconjugates located on the ECM and membrane-bound glycoproteins. We identified and cloned a new member of the galectins from embryonic kidneys, and designated it galectin-9. Since high glucose alters the expression of ECM proteins and integrins, we also investigated the influence of glucose on metanephric development. The presence of 30 mM D-glucose in metanephric organ culture induced dysmorphogenesis of the kidney accompanied by decreased expression of perlecan. Furthermore, we screened the genes differentially expressed under high glucose conditions in streptozotocin-induced newborn mouse kidneys by representational difference analysis of cDNA. We identified translocase of inner mitochondrial membrane (Tim44) and renal-specific oxido-reductase (RSOR). The roles of these molecules in glucose-induced dysmorphogenesis and the relationship with ECM-related molecules need to be addressed.
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Morris DG, Huang X, Kaminski N, Wang Y, Shapiro SD, Dolganov G, Glick A, Sheppard D. Loss of integrin alpha(v)beta6-mediated TGF-beta activation causes Mmp12-dependent emphysema. Nature 2003; 422:169-73. [PMID: 12634787 DOI: 10.1038/nature01413] [Citation(s) in RCA: 369] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2002] [Accepted: 12/23/2002] [Indexed: 12/15/2022]
Abstract
Integrins are heterodimeric cell-surface proteins that regulate cell growth, migration and survival. We have shown previously that the epithelial-restricted integrin alpha(v)beta6 has another critical function; that is, it binds and activates latent transforming growth factor-beta (TGF-beta). Through a global analysis of pulmonary gene expression in the lungs of mice lacking this integrin (Itgb6 null mice) we have identified a marked induction of macrophage metalloelastase (Mmp12)--a metalloproteinase that preferentially degrades elastin and has been implicated in the chronic lung disease emphysema. Here we report that Itgb6-null mice develop age-related emphysema that is completely abrogated either by transgenic expression of versions of the beta6 integrin subunit that support TGF-beta activation, or by the loss of Mmp12. Furthermore, we show that the effects of Itgb6 deletion are overcome by simultaneous transgenic expression of active TGF-beta1. We have uncovered a pathway in which the loss of integrin-mediated activation of latent TGF-beta causes age-dependent pulmonary emphysema through alterations of macrophage Mmp12 expression. Furthermore, we show that a functional alteration in the TGF-beta activation pathway affects susceptibility to this disease.
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259
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Da Silva MS, Horton JA, Wijelath JM, Blystone LW, Fish WR, Wijelath E, Strand K, Blystone SD, Sobel M. Heparin modulates integrin-mediated cellular adhesion: specificity of interactions with alpha and beta integrin subunits. CELL COMMUNICATION & ADHESION 2003; 10:59-67. [PMID: 14681057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
Heparin is known to influence the growth, proliferation, and migration of vascular cells, but the precise mechanisms are unknown. We previously demonstrated that unfractionated heparin (UH) binds to the platelet integrin alpha(IIb)beta(3), and enhances ligand binding. To help define the specificity and site(s) of heparin-integrin interactions, we employed the erythroleukemic K562 cell line, transfected to express specific integrins (alpha(v)beta(3), alpha(v)beta(5), and alpha(IIb)beta(3)). By comparing K562 cells expressing a common alpha subunit (Kalpha(v)beta(3), Kalpha(v)beta(5)) with cells expressing a common beta subunit (Kalpha(v)beta(3), Kalpha(IIb)beta(3)), we observed that heparin differentially modulated integrin-mediated adhesion to vitronectin. UH at 0.5-7.5 microg/ml consistently enhanced the adhesion of beta(3) expressing cells (Kalpha(v)beta(3),Kalpha(IIb)beta(3)). In contrast, UH at 0.5-7.5 microg/ml inhibited Kalpha(v)beta(5) adhesion. Experiments using integrin-blocking antibodies, appropriate control ligands, and nontransfected native K562 cells revealed that heparin's actions were mediated by the specific integrins under study. Preincubation of heparin with Kalpha(v)beta(3) cells enhanced adhesion, while preincubation of heparin with the adhesive substrate (vitronectin) had minimal effect. There was a structural specificity to heparin's effect, in that a low molecular weight heparin and chondroitin sulfate showed significantly less enhancement of adhesion. These findings suggest that heparin's modulation of integrin-ligand interactions occurs through its action on the integrin. The inhibitory or stimulatory effects of heparin depend on the beta subunit type, and the potency is dictated by structural characteristics of the glycosaminoglycan.
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Ludbrook SB, Barry ST, Delves CJ, Horgan CMT. The integrin alphavbeta3 is a receptor for the latency-associated peptides of transforming growth factors beta1 and beta3. Biochem J 2003; 369:311-8. [PMID: 12358597 PMCID: PMC1223078 DOI: 10.1042/bj20020809] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2002] [Revised: 09/13/2002] [Accepted: 10/02/2002] [Indexed: 12/31/2022]
Abstract
The integrins alpha(v)beta(1), alpha(v)beta(5), alpha(v)beta(6) and alpha(v)beta(8) have all recently been shown to interact with the RGD motif of the latency-associated peptide (LAPbeta(1)) of transforming growth factor beta(1) (TGFbeta(1)), with binding to alpha(v)beta(6) and alpha(v)beta(8) leading to TGFbeta(1) activation. Previously it has been suggested that the remaining alpha(v) integrin, alpha(v)beta(3,) does not interact with LAPbeta(1). However, here we show clearly that alpha(v)beta(3) does indeed interact with the LAPbeta(1) RGD motif. This interaction is similar to other alpha(v)beta(3) ligands in terms of the cations required for adhesion, the concentrations of LAPbeta(1) required for binding and the ability of a small-molecule inhibitor of alpha(v)beta(3), SB223245, to block the interaction. Using glutathione S-transferase fusion proteins we have mapped a minimal integrin-binding loop in LAPbeta(1) and then used this approach to probe the integrin-binding properties of the equivalent loops in LAPbeta(2) and LAPbeta(3). We show that the RGD motif of LAPbeta(3) also interacts with alpha(v)beta(3), in addition to alpha(v)beta(6), alpha(v)beta(1) and alpha(v)beta(5), whereas the corresponding loop in LAPbeta(2) does not interact with these integrins. These observations therefore correct a previously reported inaccuracy in the literature. Furthermore, they are important as they link alpha(v)beta(3) and TGFbeta, which may have implications in cancer and a number of inflammatory and fibrotic diseases where expression of both proteins has been documented.
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Zhang H, Tay PN, Cao W, Li W, Lu J. Integrin-nucleated Toll-like receptor (TLR) dimerization reveals subcellular targeting of TLRs and distinct mechanisms of TLR4 activation and signaling. FEBS Lett 2002; 532:171-6. [PMID: 12459484 DOI: 10.1016/s0014-5793(02)03669-4] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Toll-like receptors (TLRs) are activated by microbial structures. To investigate the mechanisms of TLR activation, the 10 human TLRs were expressed as chimeras with the integrin alphav and beta5 subunits. Co-expression of the alphav-TLR and beta5-TLR chimeras in 293T cells generated 10 TLR homodimers, but only TLR4/4 could effectively activate NF-kappaB. TLR4 monomers also activated NF-kappaB but it was enhanced upon homodimerization. The TLR homodimers showed differential surface/intracellular expression. In TLR heterodimers, only TLR2/1 and TLR2/6 were potent in NF-kappaB activation. NF-kappaB activation by TLR2/1, TLR2/6 and the TLR4 monomer, but not TLR4/4, was completely inhibited by dominant negative MyD88, suggesting that TLR4 homodimers and monomers could activate NF-kappaB through different mechanisms.
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262
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Berrier AL, Martinez R, Bokoch GM, LaFlamme SE. The integrin beta tail is required and sufficient to regulate adhesion signaling to Rac1. J Cell Sci 2002; 115:4285-91. [PMID: 12376560 DOI: 10.1242/jcs.00109] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Rac1 is a small Rho family GTPase that regulates changes in cell morphology associated with cell spreading and migration. Integrin-mediated adhesion is known to activate Rac1 and to regulate the interaction of Rac1 with downstream effectors. Currently, it is not clear how integrins signal Rac1 activation following cell adhesion. Integrin beta cytoplasmic domains (beta-tails) are known to be required for integrin-mediated cell spreading, and isolated beta tails expressed as tac-beta tail chimeras can inhibit cell spreading indicating that protein interactions with beta tails can regulate this process. Our recent studies demonstrated that the expression of constitutively activated Rac1 can restore cell spreading inhibited by tac beta tail chimeras, suggesting a role for Rac1 in the regulation of cell spreading by beta tails. Hence, we examined the role of beta tails in integrin activation of Rac1. By using recombinant wild-type and mutant integrin heterodimers, we demonstrate that integrin beta tails are required for adhesion to increase Rac1-GTP loading. We demonstrate that clustering tac-beta tail chimeras, on the surface of cells in suspension, activates Rac1. Thus, beta tails are not only required, but also sufficient for integrin-triggered Rac1 activation. Our findings indicate that integrin beta-tails are an important link between integrin engagement and Rac1 signaling, and that protein interactions initiated at beta tails are sufficient for integrins to regulate Rac1 activity.
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263
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Ling K, Doughman RL, Firestone AJ, Bunce MW, Anderson RA. Type I gamma phosphatidylinositol phosphate kinase targets and regulates focal adhesions. Nature 2002; 420:89-93. [PMID: 12422220 DOI: 10.1038/nature01082] [Citation(s) in RCA: 370] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2002] [Accepted: 08/01/2002] [Indexed: 11/08/2022]
Abstract
The ability of cells to form cell contacts, adhere to the extracellular matrix, change morphology, and migrate is essential for development, wound healing, metastasis, cell survival and the immune response. These events depend on the binding of integrin to the extracellular matrix, and assembly of focal adhesions, which are complexes comprising scaffolding and signalling proteins organized by adhesion to the extracellular matrix. Phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P(2)) regulates interactions between these proteins, including the interaction of vinculin with actin and talin. The binding of talin to beta-integrin is strengthened by PtdIns(4,5)P(2), suggesting that the basis of focal adhesion assembly is regulated by this lipid mediator. Here we show that the type I phosphatidylinositol phosphate kinase isoform-gamma 661 (PIPKI gamma 661), an enzyme that makes PtdIns(4,5)P(2), is targeted to focal adhesions by an association with talin. PIPKI gamma 661 is tyrosine phosphorylated by focal adhesion associated kinase signalling, increasing both the activity of phosphatidylinositol phosphate kinase and its association with talin. This defines a mechanism for spatial generation of PtdIns(4,5)P(2) at focal adhesions.
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McCarty JH, Monahan-Earley RA, Brown LF, Keller M, Gerhardt H, Rubin K, Shani M, Dvorak HF, Wolburg H, Bader BL, Dvorak AM, Hynes RO. Defective associations between blood vessels and brain parenchyma lead to cerebral hemorrhage in mice lacking alphav integrins. Mol Cell Biol 2002; 22:7667-77. [PMID: 12370313 PMCID: PMC135679 DOI: 10.1128/mcb.22.21.7667-7677.2002] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mouse embryos genetically null for the alphav integrin subunit develop intracerebral hemorrhages at midgestation and die shortly after birth. A key question is whether the hemorrhage arises from primary defects in vascular endothelial cells or pericytes or from other causes. We have previously reported normal initiation of cerebral vessels comprising branched tubes of endothelial cells. Here we show that the onset of hemorrhage is not due to defects in pericyte recruitment. Additionally, most alphav-null vessels display ultrastructurally normal endothelium-pericyte associations and normal interendothelial cell junctions. Thus, endothelial cells and pericytes appear to establish their normal relationships in cerebral microvessels. However, by both light and electron microscopy, we detected defective associations between cerebral microvessels and the surrounding brain parenchyma, composed of neuroepithelial cells, glia, and neuronal precursors. These data suggest a novel role for alphav integrins in the association between cerebral microvessels and central nervous system parenchymal cells.
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Hatanaka K, Hokari R, Matsuzaki K, Kato S, Kawaguchi A, Nagao S, Suzuki H, Miyazaki K, Sekizuka E, Nagata H, Ishii H, Miura S. Increased expression of mucosal addressin cell adhesion molecule-1 (MAdCAM-1) and lymphocyte recruitment in murine gastritis induced by Helicobacter pylori. Clin Exp Immunol 2002; 130:183-9. [PMID: 12390304 PMCID: PMC1906517 DOI: 10.1046/j.1365-2249.2002.01984.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/30/2002] [Indexed: 12/18/2022] Open
Abstract
Although T cell involvement in Helicobactor pylori-induced gastritis is known, mechanism about T cell recruitment is not understood. In this study we examined how mucosal addressin cell adhesion -molecule-1 (MAdCAM-1) is involved in lymphocyte recruitment in murine chronic gastritis induced by H. pylori. C57 BL/6 mice were infected with Sydney strain (SS1). Six months after infection, the stomach was removed. The expression of adhesion molecules, MAdCAM-1, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), and the cell surface antigens CD4, CD8, CD45R/B220 or beta7-integrin were determined by immunohistochemistry. A significant increase in CD4 lymphocytes was observed in the body portion of stomach in SS1-infected mice and most of these CD4 cells express beta7-integrin, a known counter ligand for MAdCAM-1 molecule. Strong MAdCAM-1 expression was observed adjacent to these cells in the lamina propria as well as in the submucosa of SS1-infected stomach. Quantitative analysis showed that the area of MAdCAM-1 expression well correlated with the infiltration of beta7-integrin positive lymphocytes. On the other hand, expression of ICAM-1 or VCAM-1 in the lamina propria was few even in the SS1-infected stomach. Increased expression of MAdCAM-1 was well correlated to the location of lymphocytes, which express CD4 and beta7-integrin. These results suggest the possibility that MAdCAM-1 may be largely involved in the lymphocyte recruitment in the gastritis mucosa with H. pylori.
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266
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Lee HS, Millward-Sadler SJ, Wright MO, Nuki G, Al-Jamal R, Salter DM. Activation of Integrin-RACK1/PKCalpha signalling in human articular chondrocyte mechanotransduction. Osteoarthritis Cartilage 2002; 10:890-7. [PMID: 12435334 DOI: 10.1053/joca.2002.0842] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective of this study was to examine PKC isozyme expression in human articular chondrocytes and assess roles for RACK1, a receptor for activated C kinase in the mechanotransduction process. METHODS Primary cultures of human articular chondrocytes and a human chondrocyte cell line were studied for expression of PKC isozymes and RACK1 by western blotting. Following mechanical stimulation of chondrocytes in vitro in the absence or presence of anti-integrin antibodies and RGD containing oligopeptides, subcellular localization of PKCalpha and association of RACK1 with PKCalpha and beta1 integrin was assessed. RESULTS Human articular chondrocytes express PKC isozymes alpha, gamma, delta, iota, and lambda. Following mechanical stimulation at 0.33Hz chondrocytes show a rapid, beta1 integrin dependent, translocation of PKCalpha to the cell membrane and increased association of RACK1 with PKCalpha and beta1 integrin. CONCLUSIONS RACK1 mediated translocation of activated PKCalpha to the cell membrane and modulation of integrin-associated signaling are likely to be important in regulation of downstream signaling cascades controlling chondrocyte responses to mechanical stimuli.
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Woodside DG, Obergfell A, Talapatra A, Calderwood DA, Shattil SJ, Ginsberg MH. The N-terminal SH2 domains of Syk and ZAP-70 mediate phosphotyrosine-independent binding to integrin beta cytoplasmic domains. J Biol Chem 2002; 277:39401-8. [PMID: 12171941 DOI: 10.1074/jbc.m207657200] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Syk and ZAP-70 form a subfamily of nonreceptor tyrosine kinases that contain tandem SH2 domains at their N termini. Engagement of these SH2 domains by tyrosine-phosphorylated immunoreceptor tyrosine-based activation motifs leads to kinase activation and downstream signaling. These kinases are also regulated by beta3 integrin-dependent cell adhesion via a phosphorylation-independent interaction with the beta3 integrin cytoplasmic domain. Here, we report that the interaction of integrins with Syk and ZAP-70 depends on the N-terminal SH2 domain and the interdomain A region of the kinase. The N-terminal SH2 domain alone is sufficient for weak binding, and this interaction is independent of tyrosine phosphorylation of the integrin tail. Indeed, phosphorylation of tyrosines within the two conserved NXXY motifs in the integrin beta3 cytoplasmic domain blocks Syk binding. The tandem SH2 domains of these kinases bind to multiple integrin beta cytoplasmic domains with varying affinities (beta3 (Kd = 24 nm) > beta2 (Kd = 38 nm) > beta1 (Kd = 71 nm)) as judged by both affinity chromatography and surface plasmon resonance. Thus, the binding of Syk and ZAP-70 to integrin beta cytoplasmic domains represents a novel phosphotyrosine-independent interaction mediated by their N-terminal SH2 domains.
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268
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Whittaker CA, Hynes RO. Distribution and evolution of von Willebrand/integrin A domains: widely dispersed domains with roles in cell adhesion and elsewhere. Mol Biol Cell 2002; 13:3369-87. [PMID: 12388743 PMCID: PMC129952 DOI: 10.1091/mbc.e02-05-0259] [Citation(s) in RCA: 535] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The von Willebrand A (VWA) domain is a well-studied domain involved in cell adhesion, in extracellular matrix proteins, and in integrin receptors. A number of human diseases arise from mutations in VWA domains. We have analyzed the phylogenetic distribution of this domain and the relationships among approximately 500 proteins containing this domain. Although the majority of VWA-containing proteins are extracellular, the most ancient ones, present in all eukaryotes, are all intracellular proteins involved in functions such as transcription, DNA repair, ribosomal and membrane transport, and the proteasome. A common feature seems to be involvement in multiprotein complexes. Subsequent evolution involved deployment of VWA domains by Metazoa in extracellular proteins involved in cell adhesion such as integrin beta subunits (all Metazoa). Nematodes and chordates separately expanded their complements of extracellular matrix proteins containing VWA domains, whereas plants expanded their intracellular complement. Chordates developed VWA-containing integrin alpha subunits, collagens, and other extracellular matrix proteins (e.g., matrilins, cochlin/vitrin, and von Willebrand factor). Consideration of the known properties of VWA domains in integrins and extracellular matrix proteins allows insights into their involvement in protein-protein interactions and the roles of bound divalent cations and conformational changes. These allow inferences about similar functions in novel situations such as protease regulators (e.g., complement factors and trypsin inhibitors) and intracellular proteins (e.g., helicases, chelatases, and copines).
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Spillmann C, Osorio D, Waugh R. Integrin activation by divalent ions affects neutrophil homotypic adhesion. Ann Biomed Eng 2002; 30:1002-11. [PMID: 12449761 DOI: 10.1114/1.1511241] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Activation of beta 2 integrins on leukocytes, via receptor clustering or affinity changes, is a key step in the inflammatory response. To evaluate the importance of integrin affinity changes for the formation of adhesive contacts, divalent cations were used to modulate beta 2-integrin affinity without causing a general activation of neutrophils. Two neutrophils were brought into repeated contact with micropipettes and the probability of forming an adhesive contact was measured for neutrophils exposed to different cations. In the presence of magnesium and manganese, which induce a high affinity integrin conformation, the adhesion frequency was 12%-14%. In the presence of calcium (which stabilizes the low-affinity state) the frequency of adhesion was reduced (2.4 +/- 2.1%) and in the absence of divalent cations there were no adhesive contacts. The adhesive probability was not affected by addition of soluble VCAM-1, but was significantly reduced to 7 +/- 3% in the presence of magnesium plus a soluble form of ICAM-1. Addition of a blocking anti-beta 2-integrin Fab fragment also significantly reduced the probability of forming an adhesive contact to 4 +/- 2%. Thus increased beta 2-integrin affinity promotes homotypic neutrophil adhesion during cell collisions, but the adhesion strength is weak compared to forces observed in cell arrest and migration.
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Fukatsu K, Kudsk KA, Zarzaur BL, Sabek O, Wilcox HG, Johnson CD. Increased ICAM-1 and beta2 integrin expression in parenterally fed mice after a gut ischemic insult. Shock 2002; 18:119-24. [PMID: 12166773 DOI: 10.1097/00024382-200208000-00005] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Lack of enteral feeding increases P- and E-selectin and ICAM-1 expression on endothelial cells in organs, such as the small intestine and lung, and increases neutrophils in the intestine. These changes are associated with increased mortality after gut ischemia. We hypothesize that nutritional regimen affects endothelial ICAM-1 levels and leukocyte beta2 integrins after gut ischemia. Mice received chow, intravenous (IV) TPN, or intragastric (IG) TPN. In experiment 1, after 5 days of diet, 28 mice underwent 15 min of superior mesenteric artery (SMA) occlusion (I/R) for quantification of ICAM-1 expression in organs 3 h later. In experiment 2, after the same nutrient pretreatments of 38 mice, peripheral blood was obtained with or without gut I/R to measure CD11a and CD11b expression on myeloid cells. CD18 immunofluorescence staining was studied in the lung. Expression of ICAM-1 in the liver, kidney, and small intestine was significantly higher after IV-TPN than chow. IG-TPN reduced liver and kidney ICAM-1 levels midway between the chow and IV-TPN groups, but not intestinal expression. Expression of CD11b on the myeloid cell population in each group was similar before I/R, but CD11b levels increased after IV-TPN on circulating cells after I/R compared with all uninjured animals or injured chow or IG-TPN mice. Only IV-TPN mice had lung CD18-positive leukocytes after I/R. After I/R, lack of enteral feeding increases organ expression of ICAM-1, CD11b levels on myeloid cells, and lung of CD18 positive leukocytes. Through these changes, lack of enteral feeding may increase organ damage after gut ischemia.
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271
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Price DJ, Avraham S, Feuerstein J, Fu Y, Avraham HK. The invasive phenotype in HMT-3522 cells requires increased EGF receptor signaling through both PI 3-kinase and ERK 1,2 pathways. CELL COMMUNICATION & ADHESION 2002; 9:87-102. [PMID: 12487410 DOI: 10.1080/15419060214147] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We studied the invasion of HMT-3522 breast epithelial cells in response to epidermal growth factor (EGF), and the associated signaling pathways. HMT-3522 T4-2 cells were shown to invade Matrigel-coated Transwell membranes in response to EGF while HMT-3522 S-1 cells failed to invade when treated with EGF. Studies utilizing specific molecular inhibitors showed the importance of beta1 integrin, phosphatidylinositol 3 kinase (PI 3-kinase), p38, extracellular regulated kinase 1, 2 (Erk 1,2) MAP kinases, and metalloproteinases in invasion and motility. T4-2 cell invasion was shown to be time-dependent and also gene transcription-dependent as shown by inhibition with Actinomycin D. T4-2 cells exhibited an increased activation of MAP kinases Erk 1,2 (2-fold), EGF receptor (3-fold), and PI 3-kinase (3- to 4-fold) when compared to the S-1 cells. In response to EGF, T4-2 cells showed a 5-fold greater secretion of matrix metalloproteinase-9 (MMP-9) as compared to S-1 cells, and this increase was largely dependent on the activity of PI 3-kinase. These findings indicate that expression of the invasive phenotype in these breast epithelial cells requires increased EGF receptor signaling, involving both PI 3-kinase and Erk 1,2 activities, which leads to multiple downstream effects, including enhanced secretion of MMP-9 and transcription of invasion-related genes.
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Yin L, Zhao X, Fu S, Garacia-Sanchez F, Deisseroth AB. [Correlation of cell apoptosis induction with expression of human beta5 integrin on hematopoietic cells]. ZHONGHUA XUE YE XUE ZA ZHI = ZHONGHUA XUEYEXUE ZAZHI 2001; 22:13-6. [PMID: 11877043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
OBJECTIVE To investigate the function of alpha(v)beta5 integrin in hematopoietic cells. METHODS Beta5 integrin cDNA was expressed in K562 cells through a retroviral vector system. The changes of the alpha(v)beta5 and alpha(v)beta3 integrins expression in apoptosis and differentiation induced by serum depletion were observed. RESULT The beta5 integrin cDNA failed to express in K562 cells after the introduction of the beta5 integrin retrovirus vector pG beta5CHT. Imbalanced expression of alpha(v)beta3 and alpha(v)beta5 integrins occurred during apoptosis and differentiation induced by serum depletion. Treatment of hematopoietic cells with anti-alpha(v)beta5 monoclonal antibody inhibited the cells apoptosis. CONCLUSION Overexpression of the alpha(v)beta5 integrin cDNA in hematopoietic cells was associated with the inhibition of cell proliferation and apoptosis.
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Ylänne J. Conserved functions of the cytoplasmic domains of integrin beta subunits. FRONTIERS IN BIOSCIENCE : A JOURNAL AND VIRTUAL LIBRARY 1998; 3:d877-86. [PMID: 9693157 DOI: 10.2741/a329] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In this article I will discuss the notion that many integrins have similar functions in cell spreading, organization of the cytoskeleton and intracellular signalling. Most of these functions are transmitted through the cytoplasmic domains of integrin beta-subunits. These parts are also quite conserved between most integrins. I will discuss, what is known about the molecules binding to these parts of integrins, and which of those transmit the conserved functions.
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