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Adhesive Interactions (adhesive + interaction)

Distribution by Scientific Domains

Medical Sciences	85%
Life Sciences	14%

Selected Abstracts

Antecedent Ethanol Attenuates Cerebral Ischemia/Reperfusion-Induced Leukocyte-Endothelial Adhesive Interactions and Delayed Neuronal Death: Role of Large Conductance, Ca2+ -activated K+ Channels

MICROCIRCULATION, Issue 6 2010
QUN WANG
Please cite this paper as: Wang, Kalogeris, Wang, Jones and Korthuis (2010). Antecedent Ethanol Attenuates Cerebral Ischemia/Reperfusion-Induced Leukocyte-Endothelial Adhesive Interactions and Delayed Neuronal Death: Role of Large Conductance, Ca2+ -activated K+ Channels. Microcirculation17(6), 427,438. Abstract EtOH-PC reduces postischemic neuronal injury in response to cerebral (I/R). We examined the mechanism underlying this protective effect by determining (i) whether it was associated with a decrease in I/R-induced leukocyte-endothelial adhesive interactions in postcapillary venules, and (ii) whether the protective effects were mediated by activation of large conductance, calcium-activated potassium (BKCa) channels. Mice were administered ethanol by gavage or treated with the BKCa channel opener, NS1619, 24 hours prior to I/R with or without prior treatment with the BKCa channel blocker, PX. Both CCA were occluded for 20 minutes followed by two and three hours of reperfusion, and rolling (LR) and adherent (LA) leukocytes were quantified in pial venules using intravital microscopy. The extent of DND, apoptosis and glial activation in hippocampus were assessed four days after I/R. Compared with sham, I/R elicited increases in LR and LA in pial venules and DND and apoptosis as well as glial activation in the hippocampus. These effects were attenuated by EtOH-PC or antecedent NS1619 administration, and this protection was reversed by prior treatment with PX. Our results support a role for BKCa channel activation in the neuroprotective effects of EtOH-PC in cerebral I/R. [source]

Expression patterns of focal adhesion associated proteins in the developing retina

DEVELOPMENTAL DYNAMICS, Issue 4 2002
Ming Li
Abstract Adhesive interactions between integrin receptors and the extracellular matrix (ECM) are intimately involved in regulating development of a variety of tissues within the organism. In the present study, we have investigated the relationships between ,1 integrin receptors and focal adhesion associated proteins during eye development. We used specific antibodies to examine the distribution of ,1 integrin ECM receptors and the cytoplasmic focal adhesion associated proteins, talin, vinculin, and paxillin in the developing Xenopus retina. Immunoblot analysis confirmed antibody specificity and indicated that ,1 integrins, talin, vinculin, and paxillin were expressed in developing retina and in the retinal-derived Xenopus XR1 glial cell line. Triple-labeling immunocytochemistry revealed that talin, vinculin, paxillin, and phosphotyrosine proteins colocalized with ,1 integrins at focal adhesions located at the termini of F-actin filaments in XR1 cells. In the retina, these focal adhesion proteins exhibited developmentally regulated expression patterns during eye morphogenesis. In the embryonic retina, immunoreactivities for focal adhesion proteins were expressed in neuroepithelial cells, and immunoreactivity was especially strong at the interface between the optic vesicle and overlying ectoderm. At later stages, these proteins were expressed throughout all retinal layers with higher levels of expression observed in the plexiform layers, optic fiber layer, and in the region of the inner and outer limiting membrane. Strong immunoreactivities for ,1 integrin, paxillin, and phosphotyrosine were expressed in the radially oriented Müller glial cells at later stages of development. These results suggest that focal adhesion-associated proteins are involved in integrin-mediated adhesion and signaling and are likely to be essential in regulating retinal morphogenesis. © 2002 Wiley-Liss, Inc. [source]

Serum-free cultured keratinocytes fail to organize fibronectin matrix and possess different distribution of beta-1 integrins

EXPERIMENTAL DERMATOLOGY, Issue 2 2001
G. Altankov
Abstract: The development of serum free medium formulation for culturing keratinocytes was a breakthrough in achieving a high number of epidermal cells for experimental and therapeutic studies, in particular to support the wound healing process. It is not clear, however, if switching the cells to highly proliferative phenotype may reflect change in other cellular functions important for the wound repair as their adhesive interactions with the extracellular matrix components. Remodelling of the extracellular matrix, particularly of fibronectin plays an essential role for guiding the cells during wound healing. The molecular mechanisms for organization of this provisional fibronectin matrix, however, are still not clear. We found that keratinocytes in serum containing medium, although in fewer numbers than fibroblasts, were able to remove adsorbed fluorescent labelled fibronectin from the substratum and reorganize it in a fibrilar pattern along the cell periphery. After 3 days the secreted fibronectin had also been organized as matrix-like fibers and as clusters deposited on the substratum after migrating cells. In contrast, serum free cultured keratinocytes fail to organize pre-adsorbed fluorescent labelled fibronectin, as well as the secreted fibronectin, although they grow very well under these conditions. Switching the cells to serum containing medium initiates the removal of fluorescent labelled fibronectin from the substratum, however without reorganization in fibrillar pattern. Most likely, these keratinocytes remove fluorescent labelled fibronectin by the expression of proteolytic activity, rather than with the mechanical function of ,1 integrins. The latter were diffusely dispersed in serum containing conditions and tend to organize in focal adhesions in serum free cultured cells. We assumed their transient expression and different affinity state might be important for the keratinocyte migration and matrix assembly mechanism. [source]

Tamoxifen resistance in MCF7 cells promotes EMT-like behaviour and involves modulation of ,-catenin phosphorylation

INTERNATIONAL JOURNAL OF CANCER, Issue 2 2006
Stephen Hiscox
Abstract We have previously demonstrated that, following acquisition of endocrine resistance, breast cancer cells display an altered growth rate together with increased aggressive behaviour in vitro. Since dysfunctional cell,cell adhesive interactions can promote an aggressive phenotype, we investigated the integrity of this protein complex in our breast cancer model of tamoxifen resistance. In culture, tamoxifen-resistant MCF7 (TamR) cells grew as loosely packed colonies with loss of cell,cell junctions and demonstrated altered morphology characteristic of cells undergoing epithelial-to-mesenchymal transition (EMT). Neutralising E-cadherin function promoted the invasion and inhibited the aggregation of endocrine-sensitive MCF7 cells, whilst having little effect on the behaviour of TamR cells. Additionally, TamR cells had increased levels of tyrosine-phosphorylated ,-catenin, whilst serine/threonine-phosphorylated ,-catenin was decreased. These cells also displayed loss of association between ,-catenin and E-cadherin, increased cytoplasmic and nuclear ,-catenin and elevated transcription of ,-catenin target genes known to be involved in tumour progression and EMT. Inhibition of EGFR kinase activity in TamR cells reduced ,-catenin tyrosine phosphorylation, increased ,-catenin,E-cadherin association and promoted cell,cell adhesion. In such treated cells, the association of ,-catenin with Lef-1 and the transcription of c-myc, cyclin-D1, CD44 and COX-2 were also reduced. These results suggest that homotypic adhesion in tamoxifen-resistant breast cancer cells is dysfunctional due to EGFR-driven modulation of the phosphorylation status of ,-catenin and may contribute to an enhanced aggressive phenotype and transition towards a mesenchymal phenotype in vitro. © 2005 Wiley-Liss, Inc. [source]

Role of the Bone Marrow Microenvironment in Multiple Myeloma,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 11 2002
G. David Roodman M.D., Ph.D.
Abstract On June 26,27, 2001, the Sixth Research Roundtable in Multiple Myeloma, entitled "The Role of the Bone Microenvironment in Multiple Myeloma," was held and focused on the biology of cell-to-cell interactions, the mediators of bone disease, and novel treatment strategies for myeloma. Studies on cell-cell interactions showed that vascular cell adhesion molecule 1, expressed by local endothelial and stromal cells, binds to tumor cell surface integrins in which expression may be increased by tumor cell-derived chemokines such as macrophage inflammatory protein (MIP) 1,. These adhesive interactions increase production and release of vascular endothelial growth factor (VEGF). Studies on myeloma bone disease showed the ligand for receptor activator of nuclear transcription factor-,B (RANKL) was expressed on tumor cells and stromal cells associated with myeloma cells and was critical for osteoclast-induced osteolysis. Blockade of RANKL suppressed osteoclast maturation, bone resorption, and tumor development. Bisphosphonates, in addition to reducing osteoclast mobility and inducing osteoclast apoptosis, also decreased tumor cell adhesion to stroma. Immunomodulatory drugs such as thalidomide analogues targeted these tumor cell-stromal cell interactions, blocking both secretion of cytokines and activation of intracellular signaling pathways required for tumor survival and growth. These agents induced tumor cell apoptosis, decreased neovascularization, and potentiated natural killer cell activity. The proteasome inhibitor PS-341 also prevented expression of adhesion molecules and cytokines and triggered tumor cell apoptosis, even in drug-resistant cell lines, while showing minimal activity in healthy cells. In addition, potential therapeutic agents under investigation, which included RANKL antagonists, protein prenylation inhibitors, and osteoblast growth factors, were discussed. [source]

Regulation of chondrocyte differentiation by the actin cytoskeleton and adhesive interactions

JOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2007
Anita Woods
Chondrocyte differentiation is a multi-step process characterized by successive changes in cell morphology and gene expression. In addition to tight regulation by numerous soluble factors, these processes are controlled by adhesive events. During the early phase of the chondrocyte life cycle, cell,cell adhesion through molecules such as N-cadherin and neural cell adhesion molecule (N-CAM) is required for differentiation of mesenchymal precursor cells to chondrocytes. At later stages, for example in growth plate chondrocytes, adhesion signaling from extracellular matrix (ECM) proteins through integrins and other ECM receptors such as the discoidin domain receptor (DDR) 2 (a collagen receptor) and Annexin V is necessary for normal chondrocyte proliferation and hypertrophy. Cell,matrix interactions are also important for chondrogenesis, for example through the activity of CD44, a receptor for Hyaluronan and collagens. The roles of several signaling molecules involved in adhesive signaling, such as integrin-linked kinase (ILK) and Rho GTPases, during chondrocyte differentiation are beginning to be understood, and the actin cytoskeleton has been identified as a common target of these adhesive pathways. Complete elucidation of the pathways connecting adhesion receptors to downstream effectors and the mechanisms integrating adhesion signaling with growth factor- and hormone-induced pathways is required for a better understanding of physiological and pathological skeletal development. J. Cell. Physiol. 213: 1,8, 2007. © 2007 Wiley-Liss, Inc. [source]

Antecedent Ethanol Attenuates Cerebral Ischemia/Reperfusion-Induced Leukocyte-Endothelial Adhesive Interactions and Delayed Neuronal Death: Role of Large Conductance, Ca2+ -activated K+ Channels

Differential Roles of CD36, ICAM-1, and P-selectin in Plasmodium falciparum Cytoadherence In Vivo

MICROCIRCULATION, Issue 6 2007
Bryan G. Yipp
ABSTRACT Cytoadherence of Plasmodium falciparum -infected red blood cells (IRBCs) on human microvascular endothelium is mediated by synergistic adhesive interactions with different adhesion molecules in vitro. Here, the authors used a unique human/severe combined immunodeficient (SCID) mouse chimeric model to directly visualize IRBC,endothelial interactions in an intact human microvasculature in vivo. Stimulation of human skin grafts with 100 ng TNF-, for 4 h led to a dramatic reduction in the distance rolled by IRBCs before arrest, so that the majority of IRBCs adhered directly to the endothelium with a 1.8-fold increase in the number of adherent cells. The decrease in rolling distance and increase in adhesion could be reversed by anti-ICAM-1. More importantly, the effect of TNF-, could be seen only in the presence of CD36. A further increase in adhesion by 4.9-fold was observed after 24 h of TNF-, stimulation. The increase could be reversed by anti-ICAM-1, but not anti-VCAM-1. In histamine-stimulated grafts, the rolling flux fraction and adhesion increased by 2.8- and 1.6-fold, respectively. The increases were attributable to P-selectin as an inhibitory anti-P-selectin antibody abrogated both the increased rolling flux fraction and firm adhesion. These findings indicate that in addition to CD36, ICAM-1, and P-selectin are major contributors to the dynamic process of IRBC adhesion by different mechanisms in vivo. [source]

Role of Platelets in Hypercholesterolemia-Induced Leukocyte Recruitment and Arteriolar Dysfunction

MICROCIRCULATION, Issue 5 2006
KAREN Y. STOKES
ABSTRACT Objective: To define the contribution of platelets, specifically platelet-associated P-selectin, to the altered venular and arteriolar responses induced by hypercholesterolemia. Methods: Leukocyte and platelet recruitment in cremasteric venules, and endothelium-dependent relaxation (EDR) in arterioles were determined using intravital videomicroscopy. Wild-type (WT) mice were placed on a normal or high cholesterol diet. Hypercholesterolemic mice were treated with blocking antibodies against either P-selectin or PSGL-1, or were depleted of neutrophils (ANS) or platelets (APS). Bone marrow chimeras (P-selectin deficiency in platelets, but not in endothelial cells) were produced by transplanting bone marrow from P-selectin,/, into WT mice (P-sel,/,, WT). Results: Hypercholesterolemia (HC) elicited the recruitment of adherent platelets and leukocytes in venules and an impaired EDR in arterioles. The exaggerated cell adhesion responses were absent in hypercholesterolemic mice treated with ANS, anti-P-selectin or anti-PSGL-1 antibodies and in P-sel,/,, WT chimeras. The hypercholesterolemia-induced impairment of arteriolar EDR was significantly blunted in mice rendered either neutropenic or thrombocytopenic, and in P-sel,/,, WT chimeras. Conclusions: The findings indicate that platelet-associated P-selectin contributes to the recruitment of leukocytes and platelets in venules of hypercholesterolemic mice and that the P-selectin-mediated adhesive interactions also contribute to the impaired arteriolar function induced by hypercholesterolemia. [source]

Microvascular Thrombosis Models in Venules and Arterioles In Vivo

MICROCIRCULATION, Issue 3 2005
ROLANDO E. RUMBAUT MD
ABSTRACT Platelets are intimately involved in hemostasis and thrombosis. Under physiological conditions, circulating platelets do not interact with microvascular walls. However, in response to microvascular injury, platelet adhesion and subsequent thrombus formation may be observed in venules and arterioles in vivo. Numerous intravital video microscopy techniques have been described to induce and monitor the formation of microvascular thrombi. The mechanisms of microvascular injury vary widely among different models. Some models induce platelet activation with minimal effects on endothelium, others induce endothelial inflammation or injury, while other models lead to thrombus formation associated with endothelial denudation. The molecular mechanisms mediating platelet,vessel wall adhesive interactions differ among various models. In some instances, differences in responses between venules and arterioles are described that cannot be explained solely by hemodynamic factors. Several models for induction of microvascular thrombosis in vivo are outlined in this review, with a focus on the mechanisms of injury and thrombus formation, as well as on differences in responses between venules and arterioles. Recognizing these characteristics should help investigators select an appropriate model for studying microvascular thrombosis in vivo. [source]

Regulation of Endothelial Cell Adhesion Molecule Expression in an Experimental Model of Cerebral Malaria

MICROCIRCULATION, Issue 6 2002
PHILLIPE R. BAUER
ABSTRACT Objective: Plasmodium falciparum malaria in humans and animal models of this disease have revealed changes in the infected host that are consistent with a systemic inflammatory response. Although it has been proposed that endothelial cell adhesion molecules (CAM) contribute to the adhesive interactions of Plasmodium -infected erythrocytes and immune cells with vascular endothelial cells, ECAM expression has not been systematically studied in Plasmodium -infected animals. Methods: In this study, the dual radiolabeled monoclonal antibody method was used to quantify the expression of different ECAMs (ICAM-1, VCAM-1, P-selectin, E-selectin) in different regional vascular beds of Plasmodium berghei ANKA-inffected mice (PbA), a well-recognized model of human cerebral malaria. The roles of T lymphocytes and certain cytokines (TNF-,, IL-12, IFN-,) in mediating the infection-induced expression of ICAM-1 and P-selectin were assessed by using relevant mutant mice. Results: Wild-type (WT) mice exhibited highly significant increases in the expression of ICAM-1, VCAM-1, and P-selectin (but not E-selectin) in all vascular beds on the 6th day of PbA infection. The PbA -induced upregulation of ICAM-1 was significantly blunted in mice that were either deficient in IFN-,, IL-12 (but not TNF1b) or T lymphocytes (Rag-1 deficiency); however, these responses were tissue specific. Conclusions: These findings indicate that vascular endothelial cells in most regional circulations assume an inflammatory phenotype and that cytokines and immune cells mediate this response in a tissue-specific manner. [source]

Both Fc, and complement receptors mediate transfer of immune complexes from erythrocytes to human macrophages under physiological flow conditions in vitro

CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2006
A. L. Hepburn
Summary Abnormal clearance by the mononuclear phagocytic system of immune complexes (IC) is important in the pathogenesis of systemic lupus erythematosus (SLE). We have developed an in vitro model to investigate the cellular mechanisms involved in the transfer of soluble IC from erythrocytes to human macrophages under physiological flow conditions. In this assay, erythrocytes bearing fluorescently labelled IC are perfused over monolayers of human monocytes or monocyte-derived macrophages in a parallel-plate flow chamber, and transfer quantified using confocal microscopy and flow cytometry. Using aggregated human IgG as a model IC, we have been able to demonstrate transfer of IC from erythrocytes to macrophages. Blocking studies with specific neutralizing antibodies have shown that both complement and Fc, receptors are required for IC transfer. Blockade of CR4 (,x,2 integrin), Fc,RIIa or Fc,RIII reduced transfer, while anti-CR3 (,m,2 integrin) had no effect. Blockade of CR3, Fc,RIIa or Fc,RIII also reduced the number of adhesive interactions between fluorescently labelled IC-bearing erythrocytes and macrophage monolayers. Taken together with the transfer data, this suggests differing roles for these receptors in the human IC transfer reaction that includes an adhesive function which facilitates IC processing by mononuclear phagocytes. Finally, a functional effect of the Fc,RIIa R131/H131 polymorphism, important in susceptibility to SLE, has also been demonstrated using this model. Uptake of IgG2 but not IgG1 -containing soluble IC was reduced by macrophages from individuals homozygous for the R131 allelic variant of the receptor. [source]

Dynamic Aspects Of Platelet Adhesion Under Flow

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 5-6 2001
Sacha M Dopheide
SUMMARY 1. Cell,cell and cell,matrix adhesive interactions are critical for a wide range of physiological processes, including embryogenesis, inflammation, immunity and haemostasis. 2. The ability of circulating blood cells, such as platelets and leucocytes, to adhere to sites of vascular injury is complicated by the presence of blood flow, which imposes hydrodynamic forces on adhesion contacts. 3. To overcome this problem, platelets and leucocytes have evolved specific adhesion receptors with unique biomechanical properties that enable these cells to adhere to the vessel wall under flow conditions. 4. Platelet adhesion in the normal circulation appears to be a multiple-step process involving an initial reversible interaction between the platelet adhesion receptor glycoprotein Ib-IX-V and the vascular adhesion protein von Willebrand factor. Once tethered to the vessel wall, platelets form irreversible adhesion contacts through the binding of one or more platelet integrins to specific subendothelial matrix proteins. 5. There is now a wealth of evidence demonstrating that these receptors not only mediate platelet adhesion, but also transduce signals leading to platelet activation. 6. In the present review, we will briefly discuss the current understanding of the specific roles of individual platelet receptors in supporting the haemostatic function of platelets and discuss mechanisms by which these receptors induce platelet activation. [source]