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Integrin Expression (integrin + expression)
Selected AbstractsMechanically Strained Cells of the Osteoblast Lineage Organize Their Extracellular Matrix Through Unique Sites of ,V,3 -Integrin ExpressionJOURNAL OF BONE AND MINERAL RESEARCH, Issue 9 2000Magdalena Wozniak Abstract Bone cells transduce mechanical signals into anabolic biochemical responses. However, the mechanisms of mechanotransduction are unknown. To address this issue, we performed studies in primary cells of the human osteoblast lineage grown on collagen/vitronectin-coated supports. We discovered that mechanical strain stimulated a redistribution of the ,v,3 -integrin to irregular plaque-like areas at the cell-extracellular matrix surface. Proteins involved in integrin-matrix interactions in focal adhesions, vinculin and talin, did not localize to the plaque-like areas of ,v,3 -expression, but signaling molecules such as focal adhesion kinase (FAK) did. Mechanical strain increased the number and size of the plaques defined by surface expression of ,v,3 -integrin. Osteopontin was secreted as a cross-linked macromolecular complex, likely through the action of tissue transglutaminase that also was found in the plaques of ,v,3 -integrin cell-matrix interaction. Mechanical strain increased mineralization of the extracellular matrix that developed in these plaques in ,v,3 -integrin-dependent manner. Because the plaque-like areas of cell-matrix interaction exhibit macromolecular assembly and mineralization, we conclude that they may represent subcellular domains of bone formation and that ,v,3 -integrin activation represents one mechanism by which mechanical strain stimulates bone formation. [source] Influence of Cold Plasma Atmospheric Jet on Surface Integrin Expression of Living CellsPLASMA PROCESSES AND POLYMERS, Issue 3-4 2010Alexey Shashurin Abstract The effects induced in cells due to treatment with cold atmospheric plasma jet are studied. Cell migration rate is measured by means of time-lapse microscopy. In order to characterize cell surface integrin expression, the fluorescent response of cells after surface integrins are stained with specific antibodies is measured by flow cytometry. We show that treatment of cells with plasma jet affects the cells on sub-cellular level, namely decreases expression of cell surface integrins (,1 and ,v integrins were tested). This change in integrin expression might be the original cause for the effects observed on cellular level, such as reduced cell migration rate and cell detachment observed experimentally. [source] Ultraviolet B radiation suppresses Langerhans cell migration in the dermis by down-regulation of ,4 integrinPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 3 2006Motoko Hamakawa Background/Purpose: Ultraviolet B (UVB) radiation affects the migration and function of epidermal Langerhans cells (LC) and causes immunosuppression of contact hypersensitivity. It is known that LC leaves the epidermis after exposure to UVB. To know the behavior of LC in the dermis after UVB radiation, we studied the effect of UVB radiation on the expression of integrin families on freshly isolated or cultured murine LC. We also examined whether UVB radiation affects the migration of LC to secondary lymphoid tissue chemokine (SLC/6Ckine). Methods: Integrin expressions of murine LC cultured in epidermal cell suspension were analyzed using flowcytometry. We used murine LC sorted flowcytometrically for binding assay to extracellular matrix and for migration assay to chemokine. Skin explant assay and immnohistochemical staining for ,cords formation' were performed as previously described. Results: Twenty and 40 mJ/cm2 of UVB radiation down-regulated the expression of ,4 integrin on 24 h-cultured LC, but not that of ,6, ,1, or ,4 integrin. The number of cultured LC adhered to fibronectin, a ligand for ,4 integrin, was decreased after UVB irradiation, while that to laminin, a ligand for ,6 integrin, was not influenced. UVB radiation reduced the number of migrating LC to SLC. Furthermore, skin sheet explant experiments showed that UVB radiation inhibited the ,cords' formation in dermal vessels of the 48 h-cultured skin. Conclusions: These data suggest that UVB radiation may suppress the migration of LC from the dermis to lymphatic vessels. UVB radiation may downregulate the adherence of LC to dermal fibronectin and migration to SLC, and consequently suppress the migration of LC from the UVB-irradiated dermis to lymphatics. [source] In the hypoxic central nervous system, endothelial cell proliferation is followed by astrocyte activation, proliferation, and increased expression of the ,6,4 integrin and dystroglycanGLIA, Issue 10 2010Longxuan Li Abstract Cerebral hypoxia induces a profound angiogenic response in the central nervous system (CNS). Using a mouse model of chronic cerebral hypoxia, we previously demonstrated that angiogenic vessels in the hypoxic CNS show marked upregulation of the extracellular matrix (ECM) protein fibronectin, along with increased expression of its major receptor, ,5,1 integrin on brain endothelial cells (BEC). As cerebral hypoxia also leads to glial activation, the aim of the current study was to define the temporal relationship between BEC responses and glial cell activation in this model of cerebral hypoxia. This revealed that BEC fibronectin/,5,1 integrin expression and proliferation both reached maximal level after 4-day hypoxia. Interestingly, up to 4-day hypoxia, all dividing cells were BEC, but at later time-points proliferating astrocytes were also observed. GFAP staining revealed that hypoxia induced marked astrocyte activation that reached maximal level between 7- and 14-day hypoxia. As newly formed cerebral capillaries require ensheathment by astrocyte end-feet to acquire mature brain endothelium characteristics, we next examined how expression of astrocyte end-feet adhesion molecules is regulated by hypoxia. This showed that the astrocyte adhesion receptors ,6,4 integrin and dystroglycan were both markedly upregulated, with a time-course that closely resembled astrocyte activation. Taken together, this evidence shows that cerebral hypoxia promotes first an endothelial response, in which fibronectin promotes BEC proliferation. This is then followed by an astrocyte response, involving astrocyte activation, proliferation, and reorganization of astrocyte end-feet, which correlates with increased expression of astrocyte end-feet adhesion molecules. © 2010 Wiley-Liss, Inc. [source] Microglial expression of ,v,3 and ,v,5 integrins is regulated by cytokines and the extracellular matrix: ,5 Integrin null microglia show no defects in adhesion or MMP-9 expression on vitronectinGLIA, Issue 7 2009Richard Milner Abstract As the primary immune effector cells in the CNS, microglia play a central role in regulating inflammation. The extracellular matrix (ECM) protein vitronectin is a strong inducer of microglial activation, switching microglia from a resting into an activated potentially destructive phenotype. As the activating effect of vitronectin is mediated by ,v integrins, the aim of the current study was to evaluate the requirement of the ,v,5 integrin in mediating microglial adhesion and activation to vitronectin, by studying these events in ,5 integrin-null murine microglia. Surprisingly, ,5 integrin null microglia were not defective in adhesion to vitronectin. Further analysis showed that microglia express the ,v,3 integrin, in addition to ,v,5. Flow cytometry revealed that microglial ,v integrin expression is regulated by cytokines and ECM proteins. ,v,3 integrin expression was downregulated by IFN-,, TNF, LPS, and TGF-,1. ,v,5 expression was also reduced by IFN-,, TNF, and LPS, but strongly increased by the antiactivating factors TGF-,1 and laminin. Gel zymography revealed that ,5 integrin null microglia showed no deficiency in their expression of matrix metalloproteinase (MMP)-9 in response to vitronectin. Taken together, these data show that microglia express two different ,v integrins, ,v,3 and ,v,5, and that expression of these integrins is independently regulated by cytokines and ECM proteins. Furthermore, it reveals that the ,v,5 integrin is not essential for mediating microglial adhesion and MMP-9 expression in response to vitronectin. © 2008 Wiley-Liss, Inc. [source] Expression of ,1 integrins in human dental pulp in vivo: a comparative immunohistochemical study on healthy and chronic marginal periodontitis samplesINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2001F. Ta Abstract Aim The objective of this study was to determine the tissue distribution of ,1 integrin chains in sound human dental pulps and to compare the findings with connective tissue compartments of other organs and to pulp tissue in teeth extracted due to periodontal disease. Methodology Freshly frozen pulp tissue samples from teeth extracted for orthodontic reasons were examined and compared to samples from teeth extracted due to chronic (marginal) periodontitis. ,1 integrin chains were determined using an indirect-immunoperoxidase technique. Seven monoclonal antibodies recognizing ,1, ,2, ,3, ,4, ,5, ,6 and ,1 chains of Very Late Activation Antigen (VLA) integrins were used for this purpose. Results VLA-1, VLA-2, VLA-3 and VLA-5 were expressed by vascular endothelium and vascular smooth muscle in varying intensities in both groups. VLA-6 reactivity was observed in the basal surfaces of arterial, venous and capillary endothelia. Our results indicate that there was no significant difference in the expression of VLA integrins in sound pulp tissue when compared to the samples from chronic (marginal) periodontitis and the connective tissue compartments of other viscera. Conclusion The present findings suggest that human dental pulp tissue is not different from other connective tissue compartments in the body with respect to VLA integrin expression, and chronic marginal periodontitis does not affect pulp tissue to a histopathologically detectable extent. [source] Enrichment and transplantation of spermatogonial stem cellsINTERNATIONAL JOURNAL OF ANDROLOGY, Issue S2 2000Takashi Shinohara Spermatogenesis is a complex, highly organized process originated from stem cell spermatogonia. Because there are very few stem cells and they can only be defined by their function, the identification and isolation of these cells has been very difficult. By using a spermatogonial transplantation assay system, we have identified ,6 -and ,1 -integrin expression on stem cells, and cells isolated with these antigens were significantly enriched in stem cells. This is the first demonstration of spermatogonial stem cell-associated antigens. Analysis of two infertile mouse models, Steel/SteelDickie (Sl/Sld) and experimental cryptorchidism, showed that the number of stem cells is reduced in Sl/Sld testis. Whereas cryptorchid testes are greatly enriched for stem cells, and one in 200 cells is a stem cell. These techniques will provide an important starting point for further purification and characterization of spermatogonial stem cells. [source] IFN-, withdrawal after immunotherapy potentiates B16 melanoma invasion and metastasis by intensifying tumor integrin ,v,3 signalingINTERNATIONAL JOURNAL OF CANCER, Issue 3 2008Wei Gong Abstract Immunotherapy can effectively suppress tumor, yet complete tumor eradication occurs infrequently. The metastatic potential of remnant tumor cells after immunotherapy and the underlying mechanisms have not been fully elucidated. Here, we report that the termination of immunotherapy strikingly increases the metastatic potential of remnant melanoma. This is mainly due to the withdrawal of IFN-, after immunotherapy. The relief of IFN-, stress led to the increase of ,v,3 integrin expression in B16 cells, which increased the adhesion of B16 cells to fibrinogen, fibronectin and laminin. Through ,v,3 signaling, the activation of FAK, upregulation of cdc2, production of active MMP-2 and MMP-9 and actin polymerization were intensified in B16 cells stimulated with ECM molecules 24 h after the withdrawal of IFN-,. The i.v. injection of such tumor cells into mice resulted in more metastatic tumor nodes in lung and shortened the survival of mice. The pitfall of immunotherapy termination can be remedied by the administration of recombinant CBD-HepII polypeptide of fibronectin, which effectively inhibits ,v,3 signaling. These findings suggest that the risk of tumor metastasis can be increased after the termination of immunotherapy, due to the withdrawal of IFN-, and that targeting ,v,3 signaling pathway can improve the therapeutic effect of immunotherapeutic approaches by reducing such metastatic risk. © 2008 Wiley-Liss, Inc. [source] Expression of FGFR3 with the G380R Achondroplasia Mutation Inhibits Proliferation and Maturation of CFK2 Chondrocytic CellsJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2000Janet E. Henderson Abstract A G380R substitution in the transmembrane-spanning region of FGFR3 (FGFR3Ach) results in constitutive receptor kinase activity and is the most common cause of achondroplastic dwarfism in humans. The epiphyseal growth plates of affected individuals are disorganized and hypocellular and show aberrant chondrocyte maturation. To examine the molecular basis of these abnormalities, we used a chondrocytic cell line, CFK2, to stably express the b variant of wild-type FGFR3 or the the constitutively active FGFR3Ach. Overexpression of FGFR3 had minimal effects on CFK2 proliferation and maturation compared with the severe growth retardation found in cells expressing FGFR3Ach. Cells expressing the mutant receptor also showed an abnormal apoptotic response to serum deprivation and failed to undergo differentiation under appropriate culture conditions. These changes were associated with altered expression of integrin subunits, which effectively led to a switch in substrate preference of the immature cell from fibronectin to type II collagen. These in vitro observations support those from in vivo studies indicating that FGFR3 mediates an inhibitory influence on chondrocyte proliferation. We now suggest that the mechanism is related to altered integrin expression. [source] Expression of RNAs encoding for , and , integrin subunits in periodontitis and in cyclosporin A gingival overgrowthJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2003A.-L. Bolcato-Bellemin Abstract Background: Variation of integrin expression in healthy and diseased gingiva revealed a potential biological role for these cell matrix receptors during gingival remodeling. Aim: Here we determined the level of RNA and tissue localization of different integrin subunits in periodontitis and cyclosporin A-induced gingival overgrowth. Methods: The level of expression was determined by Reverse Transcriptase Polymerase Chain Reaction in 12 periodontitis-affected patients, four patients exhibiting severe cyclosporin A-induced gingival overgrowth and seven healthy patients as controls. Results: The RNA encoding for ,1, ,2 and ,5 integrin subunits were reduced in periodontitis gingiva. The reduction observed was stronger in cyclosporin A-treated patients as compared to the healthy controls, while RNA encoding for ,1 subunit was increased. The RNA encoding for ,6 integrin was only reduced in cyclosporin A-treated gingiva. Immunohistochemistry showed that i) integrin ,2 expression is restricted to the gingival epithelium of cyclosporin A-treated patients, ii) the reduction of ,6 integrin expression in cyclosporin A-treated gingiva is due to loss of expression at focal contacts and iii) ,1 integrin is evenly distributed in the three populations with an intensity decrease in periodontitis and cyclosporin A-treated gingiva. Conclusion: Taken together these results showed a role for the integrin receptors in periodontal diseases and cyclosporin A-induced gingival overgrowth. Zusammenfassung Die Variation der Integrin Expression bei gesunder und erkrankter Gingiva zeigt eine potentielle biologische Rolle für diese Zellmatrixrezeptoren während der gingivalen Erneuerung. Wir bestimmten hier die Level von RNA und die Gewebelokalisation von unterschiedlichen Integrin Untereinheiten bei Parodontitis und Cyclosporin A induzierter gingivaler Wucherung. Die Level der Expression wurden mit der reversen Transscriptase Polymerase Kettenreaktion bei 12 Parodontitis-Patienten, 4 Patienten mit schwerer Cyclosporin A induzierter gingivaler Wucherung und sieben gesunden Kontrollpatienten bestimmt. Die kodierende RNA für ,1, ,2 und ,5 Integrin Untereinheiten waren in der Gingiva mit Parodontitis reduziert. Die beobachtete Reduktion war stärker bei den mit Cyclosporin A behandelten Patienten verglichen mit den gesunden Kontrollen, während kodierende RNA für ,1 Untereinheiten erhöht war. Die kodierende RNA für ,6 Integrin war nur bei der Cyclosporin A behandelten Gingiva reduziert. Die Immunhistochemie zeigte (i) die Integrin ,2 Expression ist auf das gingivale Epithel von Cyclosporin A behandelten Patienten beschränkt, (ii) die Reduktion von ,6 Integrin Expression bei Cyclosporin A behandelter Gingiva ist die Folge von fokalen Expressionverlusten und (iii) ,1 Integrin ist gleichmäßig verteilt in den drei Populationen mit einer Intensitätsabnahme bei Parodontitis und Cyclosporin A behandelter Gingiva. Zusammenfassend zeigen die Ergebnisse eine Rolle für die Integrin Rezeptoren bei den parodontalen Erkrankungen und Cyclosporin A induzierter gingivalen Wucherung. Résumé La variation d'expression des intégrines dans les tissus gingivaux sain et pathologique a démontré le rôle biologique potentiel de ces récepteurs de la matrice extracellulaire au cours du remodelage tissulaire gingival. La quantité d'ARN et la localisation tissulaire de certaines sous-unités d'intégrines dans la parodontite et l'hyperplasie gingivale induite par la ciclosporine A ont été déterminées. Le niveau d'expression a étéévalué par transcription inverse des ARN et réaction de polymérisation en chaine chez douze patients atteints de parodontite, quatre patients présentant une hyperplasie gingivale sévère induite par la ciclosporine A et sept patients sains ayant servi de témoins. L'expression des ARN codant pour les sous-unités ,1, ,2 et ,5était diminuée dans le tissu gingival atteint de parodontite. La diminution observée était plus importante chez les patients traités par la ciclosporine A, comparée aux témoins sains alors que l'expression de l'ARN codant pour la sous-unité,1était augmentée. L'expression de l'ARN codant pour la sous-unité,6était diminuée uniquement dans le tissu gingival traité par la ciclosporine A. L'immohistochimie a montré que (1) l'expression de la sous-unité,2 est limitée à l'épithélium gingival des patients traités par la ciclosporine A, (2) la diminution de l'expression de la sous-unité,6 dans le tissu gingival traité par la ciclosporine A est due à une perte des contacts focaux et (3) la sous-unité,1 est répartie de manière uniforme dans les trois groupes avec une diminution de l'intensité dans les cas de parodontite et d'hyperplasie gingivale induite par la ciclosporine A. Ces résultats montrent un rôle des récepteurs de type intégrine dans la pathologie parodontale et l'hyperplasie gingivale induite par la ciclosporine A. [source] Defective ,1 -integrins expression in arsenical keratosis and arsenic-treated cultured human keratinocytesJOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2006Chih-Hung Lee Background:, ,1 -integrins, which localize to the basolateral surface of basal keratinocytes, are important in the differentiation control and proliferation of the epidermis. Many cutaneous diseases with perturbed differentiation, including arsenical keratosis, show altered patterns of integrin distribution and expression. Arsenic may induce arsenical keratosis through the differentiation and apoptosis aberration by integrins. The purpose of this study is to investigate the role of integrin and arsenic in the pathogenesis of arsenical keratosis. Methods:, Twenty-five specimens obtained from 25 patients with arsenical keratosis disease were studied. Immunohistochemistry staining to ,1, ,2,1, or ,3,1 integrins was performed in arsenical keratosis and clinically normal perilesional skin. Western blotting was used to assess the expression of integrin ,1 and focal adhesion kinase (FAK) in arsenic-treated cultured keratinocytes. Results:, A decreased expression of ,1, ,2,1, or ,3,1 integrins was demonstrated in arsenical keratosis and clinical normal perilesional skin in a large proportion of arsenical keratosis cases studied. The expressions of integrin ,1 and FAK were both decreased in arsenic-treated keratinocytes. Conclusions:, Our results suggest that arsenic induces abnormal differentiation in arsenical keratosis via the effects of integrin expression in keratinocytes. [source] Functional integrin subunits regulating cell,matrix interactions in the intervertebral discJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 6 2007Christopher L. Gilchrist Abstract Cellular interactions with the extracellular matrix are key factors regulating cell survival, differentiation, and response to environmental stimuli in cartilagenous tissues. Much is known about the extracellular matrix proteins in the intervertebral disc (IVD) and their variations with region, age, or degenerative state of the tissue. In contrast, little is known of the integrin cell surface receptors that directly bind to and interact with these matrix proteins in the IVD. In almost all tissues, these integrin-mediated cell,matrix interactions are important for transducing environmental cues arising from mechanical stimuli, matrix degradation fragments, and cytokines into intracellular signals. In this study, cells from the nucleus pulposus and anulus fibrosus regions of porcine IVDs were analyzed via flow cytometry to quantify integrin expression levels upon isolation and after monolayer culture. Assays of cell attachment to collagens, fibronectin, and laminin were performed after functional blocking of select integrin subunits to evaluate the role of specific integrins in cell attachment. In situ distribution and co-localization of integrins and laminin were also characterized. Results identify integrin receptors critical for IVD cell interactions with collagens (,1,1) and fibronectin (,5,1). Additionally, dramatic differences in cell,laminin interactions were observed between cells of the nucleus and anulus regions, including differences in ,6 integrin expression, cell adhesion to laminin, and in situ pericellular environments. These findings suggest laminin,cell interactions may be important and unique to the nucleus pulposus region of the IVD. The results of this study provide new information on functional cell,matrix interactions in tissues of the IVD. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 25: 829,840, 2007 [source] Decreased expression of ,2 integrin in fibroblasts isolated from cyclosporin A- induced gingival overgrowth in ratsJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2003Masatoshi Kataoka Objectives:, Cyclosporin A (CsA), an immunosuppressive agent, induces fibrous gingival overgrowth through reduction of collagen phagocytosis by fibroblasts. Distinct receptors are involved in the binding of collagen to fibroblasts in collagen phagocytosis, and ,2,1 integrin serves as a specific receptor for type I collagen on fibroblasts. To elucidate the role of ,2,1 integrin in CsA-induced gingival overgrowth, we investigated collagen phagocytosis and ,2,1 integrin expression in rat gingival fibroblasts. Materials and methods:, Fibroblats were isolated from gingiva of rats fed a powdered diet containing or lacking CsA for 30 d. Flow cytometric analysis were performed to measure the collagen phagocytosis and the ,2 integrin expression in fibroblasts. Furthermore, total RNAs were isolated from fibroblasts, and the reverse transcriptase-polymerase chain reaction was employed to investigate the mRNA levels of ,2 integrin. Results:,In vitro collagen phagocytosis assay revealed that CsA-treated and control fibroblasts contained a mean of 13.5% and 36.1% phagocytic cells, respectively. CsA-treated fibroblasts had 28% lower expression of ,2 integrin than that of control. and mRNA expression of ,2 integrin in CsA-treated fibroblasts was apparently lower than in the controls, but the mRNA expression of ,1 integrin was not affected. Conclusion:, These findings suggest that one etiological factor of gingival overgrowth may be inhibition of collagen phagocytosis by reducing ,2 integrin expression in gingival fibroblasts. [source] Expression and Cytoskeletal Association of Integrin Subunits Is Selectively Increased in Rat Perivenous Hepatocytes After Chronic Ethanol AdministrationALCOHOLISM, Issue 12 2001Courtney S. Schaffert Background: For normal function and survival, hepatocytes require proper cell,extracellular matrix (ECM) contacts mediated by integrin receptors and focal adhesions. Previous studies have shown that chronic ethanol consumption selectively impairs perivenous (PV) hepatocyte attachment and spreading on various ECM substrates but increases expression of the ,1 integrin subunit, the common , subunit for two major hepatocyte-ECM receptors, ,1,1 and ,5,1 integrins. This study examined the effects of ethanol treatment on the expression and cytoskeletal distribution of ,1, ,5, and ,1 integrin subunits, the epidermal growth factor receptor (EGF-R), and the cytoskeletal proteins focal adhesion kinase, paxillin, vinculin, and actin in periportal and PV hepatocytes. Methods: Periportal and PV hepatocytes were isolated from control and ethanol-fed rats. For expression analysis, lysates were examined by SDS-PAGE and immunoblotting procedures. For cytoskeletal distribution studies, Triton-soluble and -insoluble (cytoskeletal) fractions from hepatocytes cultured on collagen IV were analyzed by SDS-PAGE and immunoblotting. Results: Chronic ethanol administration caused PV-specific increases in expression and cytoskeletal association of the integrin subunits. Although ethanol treatment did not affect expression of the EGF-R in either cell type, it did increase the association of the EGF-R with the cytoskeleton selectively in PV hepatocytes. Ethanol treatment had no significant effect on either the expression or the cytoskeletal distribution of focal adhesion kinase, paxillin, vinculin, or actin in either cell type. Conclusions: The increases in integrin expression and cytoskeletal association observed after chronic ethanol administration suggest that a process downstream of integrin-ECM interactions is impaired selectively in PV hepatocytes, possibly involving altered focal adhesion assembly or turnover, processes essential for efficient cell-ECM adhesion. Alterations in these processes could contribute to the impaired hepatocyte function and structure observed after chronic ethanol administration. [source] Influence of Cold Plasma Atmospheric Jet on Surface Integrin Expression of Living CellsPLASMA PROCESSES AND POLYMERS, Issue 3-4 2010Alexey Shashurin Abstract The effects induced in cells due to treatment with cold atmospheric plasma jet are studied. Cell migration rate is measured by means of time-lapse microscopy. In order to characterize cell surface integrin expression, the fluorescent response of cells after surface integrins are stained with specific antibodies is measured by flow cytometry. We show that treatment of cells with plasma jet affects the cells on sub-cellular level, namely decreases expression of cell surface integrins (,1 and ,v integrins were tested). This change in integrin expression might be the original cause for the effects observed on cellular level, such as reduced cell migration rate and cell detachment observed experimentally. [source] Temporal and spatial regulation of ,6 integrin expression during the development of the cochlear-vestibular ganglionTHE JOURNAL OF COMPARATIVE NEUROLOGY, Issue 5 2007Dawn Davies Abstract The neurons of the cochlear-vestibular ganglion (CVG) that innervate the sensory hair cells of the inner ear are derived from the otic epithelium early in development. Neuroblasts detach from neighboring cells, migrate into the mesenchyme where they coalesce to form the ganglion complex, then send processes back into the epithelium. Cell migration and neuronal process formation involve changes in cellular interactions with other cells and proteins in the extracellular matrix that are orchestrated by cell surface-expressed adhesion molecules, including the integrins. I studied the expression pattern of the ,6 integrin subunit during the early development of the CVG using immunohistochemistry and reverse-transcriptase polymerase chain reaction (RT-PCR) in murine tissue sections, otocyst, and ganglion explants. At embryonic day (E)10.5 ,6 integrin was expressed in the otic epithelium but not in migrating neuroblasts. Importantly, the loss of ,6 was associated with exit from the epithelium, not neuronal determination, revealing differentiation cues acutely associated with the cellular environment. Markers of glial and neuronal phenotype showed that ,6-expressing cells present in the CVG at this stage were glia of neural crest origin. By E12.5 ,6 expression in the ganglion increased alongside the elaboration of neuronal processes. Immunohistochemistry applied to otocyst cultures in the absence of glia revealed that neuronal processes remained ,6-negative at this developmental stage and confirmed that ,6 was expressed by closely apposed glia. The spatiotemporal modulation of ,6 expression suggests changing roles for this integrin during the early development of inner ear innervation. J. Comp. Neurol. 502:673,682, 2007. © 2007 Wiley-Liss, Inc. [source] Glucocorticoids increase ,5 integrin expression and adhesion of synovial fibroblasts but inhibit ERK signaling, migration, and cartilage invasionARTHRITIS & RHEUMATISM, Issue 12 2009Torsten Lowin Objective In rheumatoid arthritis (RA), integrins mediate cell adhesion, migration, and invasion, and their expression is regulated by cytokines and growth factors. The aim of this study was to investigate whether hormones such as cortisol or other steroids can influence integrin expression and function in the synovial cells of patients with RA. Methods We performed immunofluorescence and fluorescence-activated cell sorting analyses to quantify surface integrin levels. Adhesion and migration assays were performed to study the function of synovial fibroblasts (SFs). ERK activation was measured by cellular activation of a signaling enzyme-linked immunosorbent assay. Invasion of SFs into cartilage was determined in the SCID mouse coimplantation model of RA in vivo. Results In RA, expression of integrin subunits ,5, ,v, and ,1 was higher at the site of invasion compared with the sublining zone. Testosterone and 17,-estradiol had no influence on integrin levels, but cortisol up-regulated expression of the ,5 subunit in a time-dependent and dose-dependent manner. In addition, cortisol increased the adhesion of SFs to fibronectin and inhibited ERK signaling upon integrin activation or upon stimulation with tumor necrosis factor. Small interfering RNA or a neutralizing antibody to ,5 integrin increased SF migration, indicating that up-regulated ,5 integrin is responsible for an immobile phenotype. In addition, in the SCID mouse model, SF invasion into cartilage was attenuated by glucocorticoid treatment in vivo. Conclusion Glucocorticoids increase integrin expression and the adhesion of cells to fibronectin, inhibit ERK signaling, and down-regulate the invasiveness of SFs in vivo. This study demonstrates that an important antiinflammatory aspect of glucocorticoids is regulating the expression and function of ,5 integrin. [source] Expression of Integrin ,v,3 in Gliomas Correlates with Tumor Grade and Is not Restricted to Tumor VasculatureBRAIN PATHOLOGY, Issue 3 2008Oliver Schnell MD Abstract In malignant gliomas, the integrin adhesion receptors seem to play a key role for invasive growth and angiogenesis. However, there is still a controversy about the expression and the distribution of ,v,3 integrin caused by malignancy. The aim of our study was to assess the extent and pattern of ,v,3 integrin expression within primary glioblastomas (GBMs) compared with low-grade gliomas (LGGs). Tumor samples were immunostained for the detection of ,v,3 integrin and quantified by an imaging software. The expression of ,v,3 was found to be significantly higher in GBMs than in LGGs, whereby focal strong reactivity was restricted to GBMs only. Subsequent analysis revealed that not only endothelial cells but also, to a large extent, glial tumor cells contribute to the overall amount of ,v,3 integrin in the tumors. To further analyze the integrin subunits, Western blots from histologic sections were performed, which demonstrated a significant difference in the expression of the ,3 integrin subunit between GBMs and LGGs. The presented data lead to new insights in the pattern of ,v,3 integrin in gliomas and are of relevance for the inhibition of ,v,3 integrin with specific RGD peptides and interfering drugs to reduce angiogenesis and tumor growth. [source] Low-energy helium,neon laser induces melanocyte proliferation via interaction with type IV collagen: visible light as a therapeutic option for vitiligoBRITISH JOURNAL OF DERMATOLOGY, Issue 2 2009C-C.E. Lan Summary Background, The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium,neon laser (He,Ne laser, 632·8 nm) is a therapeutic option for treatment of this depigmentary disorder. Objectives, Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He,Ne laser on melanocytes. Methods, Cultured melanocytes were irradiated with the He,Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Results, Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He,Ne laser stimulates melanocyte proliferation through enhanced ,2,1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He,Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He,Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. Conclusions, In summary, we have demonstrated that the He,Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He,Ne laser light in vitro and provided a solid theoretical basis regarding how the He,Ne laser induces recovery of vitiligo in vivo. [source] Rapamycin inhibits lung metastasis of B16 melanoma cells through down-regulating alphav integrin expression and up-regulating apoptosis signalingCANCER SCIENCE, Issue 2 2010Zhuoshun Yang Currently available data indicate the potential application of rapamycin and its analogues in the clinic as anticancer therapeutic agents through inhibiting tumor cell growth and tumor angiogenesis. However, whether rapamycin can directly suppress tumor metastasis remains unclear. In the present study, we demonstrated that rapamycin treatment results in reduced formation of metastatic nodules in the lung by B16 cells. This is due to two mechanisms. First, the expression of ,v integrin is down-regulated by rapamycin treatment, and subsequently, the phosphorylation of focal adhesion kinase (FAK) is reduced. Second, rapamycin promotes apoptosis by up-regulating the proapoptotic molecules Bid and Bax and down-regulating Bcl-xL. Blocking the apoptosis pathway by pan-caspase inhibitor zVAD partially reversed the suppression of rapamycin in B16 metastasis. Interestingly, rapamycin up-regulates Bax and Bid in B16 cells via the S6K1 pathway and down-regulates the expression of ,v integrin via other pathway(s). In addition, our data showed that autophagy was not involved in the mechanisms of rapamycin-mediated metastasis suppression. Our findings demonstrate a potential anti-metastatic effect of rapamycin via down-regulating ,v integrin expression and up-regulating apoptosis signaling, suggesting that rapamycin might be worthy of clinical evaluation as an antimetastatic agent. (Cancer Sci 2009) [source] 111Indium-labelled human gut-derived T cells from healthy subjects with strong in vitro adhesion to MAdCAM-1 show no detectable homing to the gut in vivoCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 1 2004J. KELSEN SUMMARY Integrin ,4,,7 is the principal gut-homing receptor, and it is assumed that expression of this specific integrin directs lymphocytes to the gut in vivo. Adoptive cellular immunotherapy against inflammatory bowel disease (IBD) may depend on the expression of integrin ,4,,7 to accomplish local delivery of intravenously injected regulatory T cells in inflamed gut mucosa. The present study aimed to investigate whether in vitro expanded human T cells from the colonic mucosa maintain integrin expression, show in vitro adhesion and retain in vivo gut-homing properties during cultivation. Whole colonic biopsies from healthy subjects were cultured in the presence of interleukin-2 (IL-2) and IL-4. The integrin expression of the cultured T cells was determined by flow cytometry and in vitro adhesion was assessed in a mucosal addressin cell adhesion molecule 1 (MAdCAM-1) adhesion assay. We studied the homing pattern after autologous infusion of 3 × 108 111Indium (111In)-labelled T cells in five healthy subjects using scintigraphic imaging. The cultured CD4+CD45RO+ gut-derived T cells express higher levels of integrin ,4,,7 than peripheral blood lymphocytes (PBLs) and show strong adhesion to MAdCAM-1 in vitro, even after 111In-labelling. Scintigraphic imaging, however, showed no gut-homing in vivo. After prolonged transit through the lungs, the T cells migrated preferentially to the spleen, liver and bone marrow. In conclusion, it is feasible to infuse autologous T cells cultured from the gut mucosa, which may be of interest in adoptive immunotherapy. Despite high expression of the gut-homing integrin ,4,,7 and adhesion to MAdCAM-1 in vitro, evaluation by 111In-scintigraphy demonstrated no gut-homing in healthy individuals. [source] Zinc, copper and manganese enhanced keratinocyte migration through a functional modulation of keratinocyte integrinsEXPERIMENTAL DERMATOLOGY, Issue 6 2000I. Tenaud Abstract: The migration of keratinocytes plays an important role in the re-epithelialization of cutaneous wounds. Zinc, copper and manganese are used in vivo for their healing properties and their mechanism of action is still only partially known. Thus, they have been shown both to promote keratinocyte proliferation and to modulate integrins expression. The aim of this study was to determine if trace elements induce an increase of the migration of keratinocytes and if this effect is related to the modulation of integrins. Two independent migration assays were used to study keratinocyte migration: the scratch assay using normal human keratinocytes and the modified Boyden chamber using HaCaT cells. Inhibition studies using function-blocking antibodies directed to ,3, ,6, ,V and ,1 subunits were performed to investigate the modulator effect of trace elements on integrin function. In this way, zinc and copper gluconates increased ,3, ,V and ,1 function whereas manganese gluconate seems mainly able to modulate the function of ,3 and ,1. The stimulating effect of these trace elements on keratinocyte migration does not appear related to ,6 subunit. Thus, zinc, copper and manganese enhanced keratinocyte migration and one of the mechanisms was going through a modulation of integrin functions. [source] Defective ,1 -integrins expression in arsenical keratosis and arsenic-treated cultured human keratinocytesJOURNAL OF CUTANEOUS PATHOLOGY, Issue 2 2006Chih-Hung Lee Background:, ,1 -integrins, which localize to the basolateral surface of basal keratinocytes, are important in the differentiation control and proliferation of the epidermis. Many cutaneous diseases with perturbed differentiation, including arsenical keratosis, show altered patterns of integrin distribution and expression. Arsenic may induce arsenical keratosis through the differentiation and apoptosis aberration by integrins. The purpose of this study is to investigate the role of integrin and arsenic in the pathogenesis of arsenical keratosis. Methods:, Twenty-five specimens obtained from 25 patients with arsenical keratosis disease were studied. Immunohistochemistry staining to ,1, ,2,1, or ,3,1 integrins was performed in arsenical keratosis and clinically normal perilesional skin. Western blotting was used to assess the expression of integrin ,1 and focal adhesion kinase (FAK) in arsenic-treated cultured keratinocytes. Results:, A decreased expression of ,1, ,2,1, or ,3,1 integrins was demonstrated in arsenical keratosis and clinical normal perilesional skin in a large proportion of arsenical keratosis cases studied. The expressions of integrin ,1 and FAK were both decreased in arsenic-treated keratinocytes. Conclusions:, Our results suggest that arsenic induces abnormal differentiation in arsenical keratosis via the effects of integrin expression in keratinocytes. [source] | ||||||||||||||||||||||||||||