Regulation of the very late antigen-4-mediated adhesive activity of normal and nonreleaser basophils: roles for Src, Syk, and phosphatidylinositol 3-kinase.

Normal human basophils express the integrin, VLA-4, and cross-linking their high-affinity IgE receptor, FcepsilonRI, increases their VLA-4-dependent adhesion to VCAM-1-transfected Chinese hamster ovary (CHO) cells. Here we show that the FcepsilonRI-mediated up-regulation of normal basophil VLA-4 adhesion is abolished by the Src inhibitor, PP1, the Syk inhibitor, ER-27319, and the phosphatidylinositol 3-kinase inhibitor, wortmannin. PP1, but not ER-27319 or wortmannin, also reduces basal adhesion and adhesion stimulated by chemotactic peptide, by Ca(++) ionophores, and by phorbol myristate acetate (PMA). Nonreleaser basophils (the consistently Syk-deficient, variably Lyn-deficient, severely degranulation-impaired cells found in about 10% of donors) share the PP1 phenotype of lowered basal adhesion, no FcepsilonRI-mediated adhesion up-regulation, and reduced adhesive responses to chemoattractant ionophores and PMA. These results implicate Src kinases in the control of basal VLA-4 activity and place Syk and phosphatidylinositol 3-kinase in the pathway linking FcepsilonRI cross-linking to VLA-4 up-regulation. Both Src and Syk-regulated components of adhesion may be impaired in nonreleaser basophils.     

Differential usage of VLA-4 and CXCR4 by CD3+CD56+ NKT cells and CD56+CD16+ NK cells regulates their interaction with endothelial cells

The mechanism that regulates the preferential accumulation of NKT cells in the BM is unknown. The BM endothelium constitutively expresses selectins, the integrin ligands VCAM-1 and ICAM-1, and the chemokine CXCL12. Both NK and NKT subsets of cells exhibited similar tethering and rolling interactions on both P-selectin and E-selectin and expressed similar levels of the integrins, VLA-4 and LFA-1. Although NKT cells express higher levels of CXCR4 than NK cells, CXCL12 (the ligand for CXCR4) rapidly stimulates similar levels of adhesion of NK and NKT cells to VCAM-1 and ICAM-1. In both subsets, the arrest on VCAM-1 was dependent on high affinity VLA-4 and the homing of these cells to the BM of NOD/SCID was VLA-4-dependent. However, as opposed to the situation for NK cells, CXCL12 preferentially triggers, under shear flow, the rolling on VCAM-1 and transendothelial migration of NKT cells. Moreover, over-expression of high levels of CXCR4 on the YT NK cell line enables them to migrate in response to CXCL12. This study therefore suggests an important role for CXCR4 levels of expression and for VLA-4 in regulating the accumulation of NKT cells in the BM.     

Lymphocyte-facilitated tumour cell adhesion to endothelial cells: the role of high affinity leucocyte integrins

AIM: Lymphocytes transiently express an active form of the beta_2 integrin LFA-1 (LFA-1Af) which has conformational changes in extracellular domains enabling higher affinity binding to the ligand ICAM-1. In this study, we investigated the role of lymphocytes bearing LFA-1Af as potential mediators of binding of ICAM-1-positive tumour cells to endothelium. METHODS: LFA-1 expression on 51Cr-PBLs was modulated in order to express high affinity LFA-1Af and conjugates were formed with 35S-labelled COLO526. The binding of the conjugates to resting or IL-1beta-stimulated human umbilical vein endothelial cells (HUVECs) was then assessed via a modified radioactive HUVEC binding assay. In addition, the binding of PBL-COLO526 conjugates to HUVECs was demonstrated by confocal microscopy. RESULTS: The binding of COLO526 to endothelial cells did not change significantly between unstimulated and stimulated HUVECs. In addition, pre-incubating the COLO526 with fresh PBLs did not significantly alter the binding of COLO526 to resting or activated HUVECs; whereas, in the presence of PBLs with LFA-1Af, the COLO526 conjugate binding dramatically increased from basal levels to 41% on resting HUVECs and 81% on stimulated HUVECs. COLO526-PBL(LFA-1Af) conjugate adhesion to stimulated HUVECs was inhibited by blocking antibody to LFA-1 (50%), VLA-4 (32%) or L-selectin (40%). Antibodies to the HUVEC adhesion molecules ICAM-1, VCAM-1 and E-selectin also inhibited COLO526-PBL(LFA-1Af) conjugate binding to activated HUVECs by 79, 60 and 73%, respectively. CONCLUSIONS: PBLs bearing LFA-1Af can enhance COLO526 adhesion to both resting and activated HUVECs. Furthermore, blocking studies demonstrate that a range of pathways are involved in this phenomenon (LFA-1/ICAM-1, VLA4/VCAM-1, L-selectin/E-selectin). These studies have identified a novel alternative pathway for lymphocyte-facilitated tumour cell adhesion to endothelial cells.     

Adhesion molecules and atherogenesis.

Atherosclerosis is an inflammatory disease of the vessel wall characterized by monocyte infiltration in response to pro-atherogenic factors such as oxidized lipids. Recently, the role of specific adhesion molecules in this process has been explored. The endothelium overlying atherosclerotic lesions expresses P-selectin and the shoulder regions express vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1), which is also expressed on endothelium in regions not prone to plaque development. Serum levels of soluble P-selectin, ICAM-1 and VCAM-1 are elevated in patients with angina pectoris or peripheral atherosclerotic disease. Reconstituted in vitro systems using monocytes on cytokine-activated endothelial cells under shear flow suggested the involvement of P-selectin, L-selectin, VCAM-1, its ligand, VLA-4 integrin and CD18 integrins. Studies of monocyte adhesion in isolated perfused carotid arteries harvested from atherosclerotic (apoE-/-) mice show a predominant involvement of P-selectin and its ligand P-selectin glycoprotein-1 (PSGL-1) in rolling and of VLA-4 and VCAM-1 in firm adhesion. Consistent with these findings, apoE-/- mice that are also deficient for P-selectin show significantly reduced atherosclerotic lesion sizes and are almost completely protected from neointimal growth after vascular injury. Milder effects are also seen in the low-density lipoprotein (LDL) receptor deficient (LDLR-/-) mouse. In a high cholesterol/cholate model, a role of ICAM-1 and CD18 integrins was also shown, but this awaits confirmation in more physiologic models. Transient blockade of the VLA-4/VCAM-1 adhesion pathway by antibodies or peptides in apoE-/- or LDLR-/- mice reduced monocyte and lipid accumulation in lesions. These data suggest that P-selectin, PSGL-1, VLA-4 and VCAM-1 are the most important adhesion molecules involved in monocyte recruitment to atherosclerotic lesions.     

The immunosuppressive drug mycophenolate mofetil impairs the adhesion capacity of gastrointestinal tumour cells

Immunosuppression correlates with the development and recurrence of cancer. Mycophenolate mofetil (MMF) has been shown to reduce adhesion molecule expression and leucocyte recruitment into the donor organ. We have hypothesized that MMF might also prevent receptor-dependent tumour dissemination. Therefore, we have investigated the effects of MMF on tumour cell adhesion to human umbilical vein endothelial cells (HUVEC) and compared them with the effects on T cell-endothelial cell interactions. Influence of MMF on cellular adhesion to HUVEC was analysed using isolated CD4+ and CD8+ T cells, or WiDr colon adenocarcinoma cells as the model tumour. HUVEC receptors ICAM-1, VCAM-1, E-selectin and P-selectin were detected by flow cytometry, Western blot or Northern blot analysis. Binding activity of T cells or WiDr cells in the presence of MMF were measured using immobilized receptor globulin chimeras. MMF potently blocked both T cell and WiDr cell binding to endothelium by 80%. Surface expression of the endothelial cell receptors was reduced by MMF in a dose-dependent manner. E-selectin mRNA was concurrently reduced with a maximum effect at 1 microm. Interestingly, MMF acted differently on T cells and WiDr cells. Maximum efficacy of MMF was reached at 10 and 1 microm, respectively. Furthermore, MMF specifically suppressed T cell attachment to ICAM-1, VCAM-1 and P-selectin. In contrast, MMF prevented WiDr cell attachment to E-selectin. In conclusion, our data reveal distinct effects of MMF on both T cell adhesion and tumour cell adhesion to endothelial cells. This suggests that MMF not only interferes with the invasion of alloactivated T cells, but might also be of value in managing post-transplantation malignancy.     

补肾宁心方对人单核-血管内皮细胞粘附的影响

目的:探讨补肾宁心方对人单核-血管内皮细胞粘附的影响及机理。方法:以培养人脐静脉内皮细胞(HUVECs)作为靶细胞,在内皮细胞培养基中加入氧化的低密度脂蛋白(ox-LDL)或在试验体系中加入灌服补肾宁心方的兔血清,以孟加拉玫瑰红活细胞染色法测定人单核细胞系U937与HUVECs的粘附,并用流式细胞仪检测内皮细胞表面粘附分子细胞间粘附分子-1(ICAM-1)、血管细胞粘附分子-1(VCAM-1)以及E-选择素的表达。结果:ox-LDL显著增强单核U937细胞与内皮细胞之间的相互粘附,如在试验体系中加入灌服补肾宁心方的动物血清,则粘附率明显降低(P＜0.01)。流式细胞仪分析结果显示ox-LDL能明显促进内皮细胞表面ICAM-1、VCAM-1以及E-选择素的表达,补肾宁心方中药灌服血清可显著下调内皮细胞表面ICAM-1、VCAM-1以及E-选择素的表达(P＜0.01)。结论:补肾宁心方含药血清可能通过下调内皮细胞表面粘附分子的表达抑制单核-血管内皮细胞粘附,从而发挥对血管内皮细胞的保护作用。     

Expression of VCAM-1, ICAM-1, E- and P-selectin and tumour-associated macrophages in renal cell carcinoma

AIMS: Neoangiogenesis is accompanied by an increase in endothelial surface, which can support infiltration by immune cells depending on adhesion molecule expression. Therefore, the expression of cell adhesion molecules on microvessels and epithelial cells was analysed in renal cell carcinomas as compared to tumour-free tissue. METHODS AND RESULTS: PECAM-1, CD34, ICAM-1, VCAM-1, VLA-4, P- and E-selectin, the macrophage antigens Ki-M1P and Mac-1, and lymphocyte function antigen LFA-1 were identified immunohistochemically. VCAM-1, ICAM-1, and E-selectin were equally or less expressed, whereas P-selectin was increased on microvessels in tumour tissue. The density of VCAM-1-positive tumour microvessels correlated positively with an advanced tumour stage and E- and P-selectin-positive tumour microvessels with the amount of associated macrophages. The expression of ICAM-1 and VCAM-1 on neoplastic epithelia correlated with an increased density of macrophages and a minor degree of tumour differentiation. CONCLUSIONS: The positive correlation of macrophage infiltration and expression of cell adhesion molecules on tumour microvessels and epithelia with minor tumour differentiation and an advanced stage indicates that adhesion molecule expression is not associated with an effective antitumour function of macrophages     

Monocyte adhesion to endothelium in simian immunodeficiency virus-induced AIDS encephalitis is mediated by vascular cell adhesion molecule-1/alpha 4 beta 1 integrin interactions.

Because the mechanisms associated with recruitment of monocytes to brain in AIDS encephalitis are unknown, we used tissues from rhesus monkeys infected with simian immunodeficiency virus (SIV) to examine the relative contributions of various adhesion pathways in mediating monocyte adhesion to endothelium from encephalitic brain. Using a modified Stamper and Woodruff tissue adhesion assay, we found that the human monocytic cell lines, THP-1 and U937, and the B cell line, Ramos, preferentially bound to brain vessels from monkeys with AIDS encephalitis. Using a combined tissue adhesion/immunohistochemistry approach, these cells only bound to vessels expressing vascular cell adhesion molecule-1 (VCAM-1). Furthermore, pretreatment of tissues with antibodies to VCAM-1 or cell lines with antibodies to VLA-4 (CD49d) inhibited adhesion by more than 70%. Intercellular adhesion molecule-1 (ICAM-1)/beta 2 integrin interactions were not significant in mediating cell adhesion to the vasculature in encephalitic simian brain using a cell line (JY) capable of binding rhesus monkey ICAM-1. In addition, selectin-mediated interactions did not significantly contribute to cell binding to encephalitic brain as there was no immunohistochemical expression of E-selectin and P-selectin in either normal or encephalitic brain, nor was there a demonstrable adhesive effect from L-selectin using L-selectin-transfected 300.19 cells on simian encephalitic brain. These results demonstrate that using the tissue adhesion assay, THP-1, U937, and Ramos cells bind to vessels in brain from animals with AIDS encephalitis using VCAM-1/alpha 4 beta 1 integrin interactions and suggest that VCAM-1 and VLA-4 may be integral for monocyte recruitment to the central nervous system during the development of AIDS encephalitis.     

Effects of the very late adhesion molecule 4 antagonist WAY103 on human peripheral blood eosinophil vascular cell adhesion molecule 1-dependent functions

BACKGROUND: Eosinophil infiltration to the lung in allergic inflammation can be initiated by the tethering of circulating cells through very late adhesion molecule 4 (VLA-4; alpha4beta1, CD49d/CD29) to vascular cell adhesion molecule 1 (VCAM-1) expressed on pulmonary vascular endothelium. Small-molecule VLA-4 antagonists have been proposed as a therapeutic mechanism to prevent eosinophil infiltration in asthma; however, they might affect other eosinophil functions. OBJECTIVE: The small-molecule VLA-4 antagonist (2S)-3-(4-Dimethylcarbamoyloxyphenyl)-2-{[(4R)-5,5-dimethyl-3-(1-methyl-1H-pyrazole-4 sulfonyl)thiazolidine-4-carbonyl]amino}propionic acid (WAY103) was assessed for its effects on eosinophil VLA-4-dependent functions, including adhesion, migration, respiratory burst, and degranulation. METHODS: Human peripheral blood eosinophils were preincubated with WAY103, anti-alpha4, and/or anti-beta2 integrin mAbs and then assessed for adhesion to recombinant VCAM-1, intercellular adhesion molecule 1, and endothelial cell monolayers. Transmigration was measured by using human pulmonary microvascular endothelial cell monolayers and Transwell filters. Superoxide anion generation was determined by means of cytochrome C reduction and degranulation by means of eosinophil-derived neurotoxin release. RESULTS: WAY103 inhibition of eosinophil adhesion to recombinant VCAM-1 was dose dependent (63% inhibition with 100 nM WAY103, P < .04) and comparable with inhibition caused by anti-alpha4 mAb (60.1% inhibition). Although pretreatment with WAY103 also decreased eosinophil adhesion to TNF-alpha plus IL-4-activated human pulmonary microvascular endothelial cell monolayers, it did not prevent eosinophil transendothelial migration in response to RANTES. Finally, WAY103 inhibited VCAM-1-stimulated superoxide generation but enhanced cytokine-activated eosinophil-derived neurotoxin degranulation. CONCLUSION: Although small-molecule VLA-4 antagonists, such as WAY103, might reduce eosinophil adhesion, this approach might not be sufficient to eliminate this cell from in vivo allergic airway inflammatory participation and could even promote specific cell activation.     

Effects of plasma treated PET and PTFE on expression of adhesion molecules by human endothelial cells in vitro

The aim of this study was to evaluate the expression of adhesion molecules on the surface of human endothelial cells in response to the systematic variation in materials properties by the ammonia plasma modification of polyethylene terephthalate (PET) and polytetrafluorethylene (PTFE). These adhesion molecules act as mediators of cell adhesion, play a role in the modulation of cell adhesion on biomaterials and therefore condition the response of tissues to implants. First and second passage human umbilical vein endothelial cells (HUVECs) were cultured on plasma treated and untreated PET and PTFE. HUVECs grown on polystyrene tissue culture coverslips and HUVECs stimulated with tumour necrosis factor (TNF-alpha) were used as controls. After 1 day and 7 days, the expression of adhesion molecules platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), Integrin alphavbeta3, vascular cell adhesion molecule-1 (VCAM-1), E-selectin, P-selectin and L-selectin were evaluated using flow cytometry and immunohistochemistry. There was a slight increase in positive cell numbers expressing the adhesion molecules ICAM-1 and VCAM-1 on plasma treated PET and PTFE. A significant increase in E-selectin positive cells on untreated PTFE was demonstrated after 7 days. Stimulation with TNF-alpha demonstrated a significant increase in the proportion of ICAM-1. VCAM-1 and E-selectin positive cells. Almost all cells expressed PECAM-1 and integrin alphavbeta3, on both materials and controls but did not express P- and L-selectin on any surface. When second passage cells were used, the expression of the adhesion molecules ICAM-1 and VCAM-1 was markedly increased on all surfaces but not with TNF-alpha. These significant differences were not observed in other adhesion molecules. These results were supported by immunohistochemical studies. The effects of plasma treated PET and PTFE on cell adhesion and proliferation was also studied. There was a 1.3-fold increase in cell numbers adhered on ammonia plasma treated PET compared to untreated PET and a 5.5-fold increase in cell numbers on treated PTFE compared to untreated PTFE after 1 day. This is significantly different when analysed statistically. After 7 days, cell number increased significantly on all surfaces compared to 1 day, except for untreated PTFE which conversely reduced by 41%. Cell number on the surface of untreated PET was no different to treated PET on days 1 and 7 when second passage cells were used. The study has shown that the plasma treatment of PET and PTFE with ammonia improves the adhesion and growth of endothelial cells and slightly upregulates the expression of adhesion molecules. This surface modification should promote colonisation of an artificial vascular prosthesis by endothelial cells and make it less vulnerable to immune system cells of the recipient. In addition, it should be considered which passage of cells is used due to the different adhesion features of different passages of HUVECs on untreated PET.     

Post-receptor occupancy events in leukocytes during β1 integrin-ligand interactions

Leukocyte adhesion to and subsequent spreading on the endothelium are the initial steps in the migration of these cells to the surrounding tissues. We have investigated the participation of different VLA heterodimers in cell spreading by using the anti-β1 TS2/16 monoclonal antibody (mAb) which induces a conformational change of different VLA integrin receptors, enabling a high-affinity interaction with their ligands. Both VLA-4 and VLA-5 fibronectin (FN), as well as VLA-2 collagen (COL) receptors mediated cell spreading and morphological changes. The spreading of U-937 and α4-transfected K-562 cells was induced in both FN and VCAM-1, suggesting that the morphological changes may be induced by cell-cell as well as cell-extracellular matrix (ECM) interactions. Furthermore, the β-regulated cell spreading on VCAM-1 and COL took place independently of the VLA-5 FN receptor function. The enhancing effect on cell attachment induced by anti-β1 TS2/16 mAb was observed in the presence of different doses of cytochalasin D, whereas cell spreading was abolished. Signal transduction during β1-stimulated integrin-ligand interaction was also investigated. We have found the co-localization of β1 integrins and tyrosine-phosphorylated proteins during the spreading of U-937 and α2- and α4-transfected K-562 cells on both ECM (FN and COL) and cellular (VCAM-1) ligands. Kinetic studies showed that tyrosine phosphorylation was almost coincident with cellular spreading. The tyrosine phosphorylation of polypeptides of 130 kDa and 77 kDa was triggered in U-937 cells by the interaction of FN with the VLA-5 receptor in a high-affinity conformation. However, no signaling was observed by inducing the high-affinity state of receptor in the absence of appropriate ligand. These data suggest that tyrosine kinase activation is a post-receptor occupancy event that might be critical in regulating the adhesive properties of integrins.     

溶血磷脂酰胆碱对内皮细胞表面粘附分子表达的影响

大量的单核细胞募集是动脉粥样损伤形成的早期表现之一,相关的内皮细胞粘附分子在其中具有积极作用。本文研究了溶血磷脂酰胆碱（Ｌｙｓｏｐｈｏｓｐｈａｔｉｄｙｌｃｈｏｌｉｎｅ,Ｌｙｓｏ－ＰＣ）对培养的人脐静脉内皮细胞（ＨＵＶＥＣｓ）膜上细胞间粘附分子－（Ｉｎｔｅｒｃｅｌｌｕｌａｒ ａｄｈｅｓｉｏｎ ｍｏｌｅｃｕｌｅ－１,ＩＣＡＭ－１）、Ｅ选择素（Ｅｎｄｏｔｈｅｌｉａｌ－ｌｅｕｋｏｃｙｔｅ ａｄｈｅｓｉｏｎ     

Increased PSGL-1 expression on granulocytes from allergic-asthmatic subjects results in enhanced leukocyte recruitment under flow conditions

Allergic asthma is increasing in incidence and severity in many industrial countries. Leukocyte recruitment into the airways of affected individuals contributes to the severity of the disease. In this study, whole blood from normal, allergic, asthmatic, or allergic-asthmatic subjects was perfused over immobilized adhesion molecules using an in vitro flow chamber system to determine if there were differences in leukocyte recruitment in these patient populations. Leukocytes from allergic-asthmatic subjects showed a threefold increase in recruitment on P-selectin as compared with normal controls. In both patient populations, the accumulated cells were exclusively neutrophils and eosinophils. Increased granulocyte recruitment was specific for P-selectin, as neither purified E-selectin nor vascular cell adhesion molecule-1 (VCAM-1) supported enhanced leukocyte recruitment from allergic-asthmatics. Leukocyte accumulation on P-selectin was completely blocked by an anti-P-selectin or anti-P-selectin glycoprotein ligand-1 (PSGL-1) monoclonal antibody. Flow cytometry revealed that neutrophils and eosinophils from allergic-asthmatic subjects had increased expression of PSGL-1, whereas expression of another adhesion molecule, L-selectin, was unchanged. PSGL-1 expression on peripheral blood mononuclear cells of allergic-asthmatic patients was unaffected. The increased PSGL-1 expression on granulocytes from allergic-asthmatic patients also led to enhanced leukocyte recruitment on interleukin-4-stimulated human umbilical vein endothelial cells, which express P-selectin and VCAM-1. Thus, increased PSGL-1 expression on granulocytes from allergic-asthmatic subjects resulted in increased leukocyte recruitment on P-selectin under flow conditions.     

Pediatric AIDS-Associated Lymphocytic Interstitial Pneumonia and Pulmonary Arterio-Occlusive Disease : Role of VCAM-1/VLA-4 Adhesion Pathway and Human Herpesviruses

Because the mechanisms of lymphocyte accumulation in the lungs of children with AIDS-associated lymphocytic interstitial pneumonia (LIP) are unknown, we studied the relative contributions of known adhesion pathways in mediating lymphocyte adherence to endothelium and the potential role of human herpesviruses in the expansion of these lesions. LIP was characterized by lymphoid hyperplasia of the bronchus-associated lymphoid tissue (BALT) and infiltration of the pulmonary interstitium with CD8(+) T lymphocytes. In some individuals there was expansion of the alveolar septae with dense aggregates of B lymphocytes, many containing the Epstein-Barr viral (EBV) genome. Patients with concurrent EBV infection also demonstrated large-vessel arteriopathy characterized by thickening of the intimae with collagen and smooth muscle. Venular endothelium from the lung of children with LIP, but not uninflamed lung from other children with AIDS or lung from children with nonspecific pneumonitis, expressed high levels of vascular cell adhesion molecule-1 (VCAM-1) protein. In turn, inflammatory cells expressing very late activation antigen-4 (VLA-4), the leukocyte ligand for VCAM-1, were the predominant perivascular infiltrate associated with vessels expressing VCAM-1. Expression of other endothelial adhesion molecules, including intracellular adhesion molecule-1 and E-selectin, was not uniformly associated with LIP. Using a tissue adhesion assay combined with immunohistochemistry for VCAM-1, we show that CD8(+) T cell clones that express VLA-4 bind preferentially to pulmonary vessels in sites of LIP: vessels that expressed high levels of VCAM-1. When tissues and cells were pretreated with antibodies to VCAM-1 or VLA-4, respectively, adhesion was inhibited by >/=80%. Thus, infiltration of alveolar septae with CD8(+) T cells was highly correlative with VCAM-1/VLA-4 adhesive interactions, and focal expansion of B cells was coincidental to co-infection with EBV.     

CD11b/CD18-coated microspheres attach to E-selectin under flow

Neutrophils can attach to E-selectin under flow. Proposed ligands for E-selectin carry SLe(x)-type glycans. The leukocyte beta2 integrins are glycosylated with SLe(x). Thus, we speculated that beta2 integrins could support attachment to E-selectin. To test this hypothesis, we coated 10-microm-diameter microspheres with purified CD11b/CD18 (alphaMbeta2) and investigated the adhesion of the resulting alphaMbeta2 microspheres to E-selectin. Under in vitro flow conditions, the alphaMbeta2 microspheres attached to Chinese hamster ovary cells expressing E-selectin (CHO-E) and 4-h interleukin-1beta-activated human umbilical vein endothelial cells (HUVEC). At a shear stress of 1.8 dynes/cm2, the attachment events were eliminated by pretreatment of the cellular monolayers with a mAb to E-selectin. alphaMbeta2 microspheres did not attach to untransfected CHO cells or unactivated HUVEC at 1.8 dynes/cm2. Taken together, the results strongly suggest that the CD11b/CD18-E-selectin bond has sufficient biophysical properties to mediate attachment of neutrophil-sized particles to E-selectin under flow.     

流体切应力对内皮细胞粘附分子表达的影响

在动脉粥样硬化(Atherosclerosis,As)的发生发展中各种白细胞,包括单核细胞对内皮细胞的粘附可能起着较为重要的作用。在体内,血流切应力对内皮细胞的形态和功能有重要影响。为了阐明流体切应力对内皮细胞表面粘附分子表达的影响,本文研究了流体切应力(2.23～6.08dyne/cm     

Biological function of CD40 on human endothelial cells: costimulation with CD40 ligand and interleukin-4 selectively induces expression of vascular cell adhesion molecule-1 and P-selectin resulting in preferential adhesion of lymphocytes

The expression of adhesion molecules on vascular endothelial cells determines the pattern of migration and extravasation of leucocytes in inflammation and immunity. Here we show that costimulation with CD40 ligand (CD40L) and interleukin (IL)-4 (or IL-13) gives rise to a unique pattern of adhesion molecule expression by human umbilical vein endothelial cells (HUVEC). CD40 ligation alone enhanced expression of vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1) and E-selectin whereas IL-4 and IL-13 increased expression of VCAM-1 and P-selectin but not ICAM-1 or E-selectin. When IL-4 and CD40L were combined there was an additional increase of both VCAM-1 and P-selectin, but ICAM-1 and E-selectin were both inhibited. The combined effects of IL-4 and CD40L signalling were not the result of altered response kinetics, enhanced sensitivity of the endothelium, or increased expression of CD40 or the IL-4 receptor. The rise in VCAM-1 expression induced by combined IL-4 and CD40L stimulation was slower and more sustained than with tumour necrosis factor-alpha (TNF-alpha) and occurred only on a subset (75-80%) of the endothelial cell population compared to 100% with TNF-alpha. Costimulation with IL-4 and CD40L increased adhesion of T cells and B cells above levels obtained with either signal alone, but decreased adhesion of neutrophils. Furthermore, CD40 and IL-4 synergistically increased IL-6 but decreased IL-8 production by HUVEC. These results show that interactions between IL-4 and CD40 on endothelial cells give rise to specific patterns of adhesion molecule expression and cytokine production that may have important implications for lymphocyte and neutrophil migration and function at sites of inflammation.     

Expression of cell adhesion molecules and their beta1 and beta2 integrin ligands in human liver peliosis

The expression of the following cell adhesion molecules and their beta1 and beta2 integrin ligands was investigated in the liver tissue from 3 patients with non-bacillar peliosis using light and electron microscope immunohistochemistry: intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, platelet endothelial cell adhesion molecule-1 (PECAM-1), leukocyte function-associated antigen-1 (LFA-1), macrophage antigen-1 (Mac-1), and very late antigen-4 (VLA-4). We found a parallel enhancement of the adhesion molecules expression in the dilated sinusoids and cavities in all 3 cases with peliosis. Mononuclear blood cells were detected in the sinusoids and sometimes perisinusoidally. These cells were mainly ICAM-1-, LFA-1-, and VLA-4-positive. At the ultrastructural level, ICAM-1-positive immune deposits were observed on the membrane of sinusoidal endothelial cells, Kupffer cells, and hepatocytes. The expression of cell adhesion molecules on liver sinusoids in peliosis is probably triggered by factors released from damaged endothelial cells and hepatocytes. The prevalence of the ICAM-1/LFA-1 and VCAM-1/VLA-4 patterns of mononuclear blood cell/sinusoidal cell interactions could support the macrophage-induced or lymphocyte-induced type of liver injury. PECAM-1 was also included in the non-specific immune response in peliosis. The presence of erythrostasis or thrombosis in liver sinusoids could participate in the induction of adhesion molecule expression in peliosis.     

Activation of beta1 integrins on blood eosinophils by P-selectin

Activation of β(1) integrins of blood eosinophils, assessed by mAb N29, correlates inversely with FEV(1) in two paradigms for studying control of human asthma. We asked whether P-selectin causes eosinophil β(1) integrin activation and results in increased adhesivity. By dual-label flow cytometry, eosinophils with high levels of surface-associated P-selectin had higher reactivity with the activation-sensitive anti-β(1) mAbs N29, 8E3, and 9EG7 than eosinophils with no or with a low-level of surface-associated P-selectin. Among patients with nonsevere asthma, surface P-selectin correlated with N29, 8E3, and 9EG7 signals. By immunofluorescence microscopy, surface-associated P-selectin was present in patches on eosinophils, some of which stained for the platelet marker thrombospondin-1. Activated β(1) and P-selectin partially colocalized on eosinophils. Soluble P-selectin added to whole blood enhanced activation of eosinophil β(1), but not β(2), integrins. In contrast, IL-5 activated eosinophil β(2), but not β(1), integrins. Eosinophils that did not attach to vascular cell adhesion molecule-1 (VCAM-1) in a static adhesion assay had a lower N29 signal than the original population. Soluble P-selectin added to whole blood enhanced eosinophil adhesion to VCAM-1. These findings are compatible with a scenario whereby P-selectin, on eosinophil-associated activated platelets or acquired from plasma or from prior interactions with endothelial cells or platelets, activates eosinophil α(4)β(1) integrin and stimulates eosinophils to adhere to VCAM-1 and move to the airway in asthma.