Sample records for beta1 integrins differentially

  1. Beta1 integrins differentially control extravasation of inflammatory cell subsets into the CNS during autoimmunity

    Bauer, Martina; Brakebusch, Cord; Coisne, Caroline;


    )-integrin gene either in all hematopoietic cells or selectively in T lymphocytes. Our results show that T cells critically rely on beta(1) integrins to accumulate in the central nervous system (CNS) during EAE, whereas CNS infiltration of beta(1)-deficient myeloid cells remains unaffected, suggesting that T...

  2. ADAM12 and alpha9beta1 integrin are instrumental in human myogenic cell differentiation

    Lafuste, Peggy; Sonnet, Corinne; Chazaud, Bénédicte; Dreyfus, Patrick A; Gherardi, Romain K; Wewer, Ulla M; Authier, François-Jérôme


    of alpha9 parallels that of ADAM12 and culminates at time of fusion. alpha9 and ADAM12 coimmunoprecipitate and participate to mpc adhesion. Inhibition of ADAM12/alpha9beta1 integrin interplay, by either ADAM12 antisense oligonucleotides or blocking antibody to alpha9beta1, inhibited overall mpc...

  3. Up-regulation of the integrin alpha 1/beta 1 in human neuroblastoma cells differentiated by retinoic acid: correlation with increased neurite outgrowth response to laminin.

    Rossino, P; P. Defilippi; Silengo, L; Tarone, G.


    Retinoic acid (RA) is known to induce differentiation of neuroblastoma cells in vitro. Here we show that treatment of two human neuroblastoma cell lines, SY5Y and IMR32, with RA resulted in a fivefold increase of the integrin alpha 1/beta 1 expression. The effect was selective because expression of the alpha 3/beta 1 integrin, also present in these cells, was not increased. The up-regulation of the alpha 1/beta 1 differentiated SY5Y cells correlated with increased neurite response to laminin....

  4. Genetic analysis of beta1 integrin "activation motifs" in mice

    Czuchra, Aleksandra; Meyer, Hannelore; Legate, Kyle R;


    /beta tails, leading to tail separation and integrin activation. We analyzed mice in which we mutated the tyrosines of the beta1 tail and the membrane-proximal aspartic acid required for the salt bridge. Tyrosine-to-alanine substitutions abolished beta1 integrin functions and led to a beta1 integrin...

  5. Staged stromal extracellular 3D matrices differentially regulate breast cancer cell responses through PI3K and beta1-integrins

    Interactions between cancer cells and stroma are critical for growth and invasiveness of epithelial tumors. The biochemical mechanisms behind tumor-stromal interactions leading to increased invasiveness and metastasis are mostly unknown. The goal of this study was to analyze the direct effects of staged stroma-derived extracellular matrices on breast cancer cell behavior. Early and late three-dimensional matrices were produced by NIH-3T3 and tumor-associated murine fibroblasts, respectively. After removing fibroblasts, extracted matrices were re-cultured with breast epithelial cells of assorted characteristics: MCF-10A (non-tumorigenic), MCF-7 (tumorigenic, non-invasive), and MDA-MB-231 (tumorigenic, invasive). Effects prompted by staged matrices on epithelial cell's growth, morphology and invasion were determined. Also, matrix-induced velocity, directionality and relative track orientation of invasive cells were assessed in the presence or absence of inhibitors of phosphoinositide-3 kinase (PI3K) and/or beta-1 integrin. We observed that assorted breast epithelial cells reacted differently to two-dimensional vs. staged, control (early) and tumor-associated (late), three-dimensional matrices. MCF-10A had a proliferative advantage on two-dimensional substrates while MCF-7 and MDA-MB-231 showed no difference. MCF-10A and MCF-7 formed morphologically distinguishable aggregates within three-dimensional matrices, while MDA-MB-231 exhibited increased spindle-shape morphologies and directional movements within three-dimensional matrices. Furthermore, MDA-MB-231 acquired a pattern of parallel oriented organization within tumor-associated, but not control matrices. Moreover, tumor-associated matrices induced PI3K and beta1-integrin dependent Akt/PKB activity in MDA-MB-231 cells. Interestingly, beta1-integrin (but not PI3K) regulated tumor-associated matrix-induced mesenchymal invasion which, when inhibited, resulted in a change of invasive strategy rather than impeding

  6. Beta 1 integrin is essential for teratoma growth and angiogenesis

    Bloch, W; Forsberg, E; Lentini, S;


    Teratomas are benign tumors that form after ectopic injection of embryonic stem (ES) cells into mice and contain derivatives of all primitive germ layers. To study the role of beta 1 integrin during teratoma formation, we compared teratomas induced by normal and beta1-null ES cells. Injection of...... normal ES cells gave rise to large teratomas. In contrast, beta 1-null ES cells either did not grow or formed small teratomas with an average weight of <5% of that of normal teratomas. Histological analysis of beta 1-null teratomas revealed the presence of various differentiated cells, however, a much...... lower number of host-derived stromal cells than in normal teratomas. Fibronectin, collagen I, and nidogen were expressed but, in contrast to normal teratomas, diffusely deposited in beta1-null teratomas. Basement membranes were present but with irregular shape and detached from the cell surface. Normal...

  7. Conditional beta1-integrin gene deletion in neural crest cells causes severe developmental alterations of the peripheral nervous system

    Pietri, Thomas; Eder, Olivier; Breau, Marie Anne;


    Integrins are transmembrane receptors that are known to interact with the extracellular matrix and to be required for migration, proliferation, differentiation and apoptosis. We have generated mice with a neural crest cell-specific deletion of the beta1-integrin gene to analyse the role of beta1-...... almost complete absence of Schwann cells and sensory axon segregation and defective maturation in neuromuscular synaptogenesis. Thus, beta1-integrins are important for the control of embryonic and postnatal peripheral nervous system development....

  8. ADAM12 induces actin cytoskeleton and extracellular matrix reorganization during early adipocyte differentiation by regulating beta1 integrin function

    Kawaguchi, Nobuko; Sundberg, Christina; Kveiborg, Marie;


    Changes in cell shape are a morphological hallmark of differentiation. In this study we report that the expression of ADAM12, a disintegrin and metalloprotease, dramatically affects cell morphology in preadipocytes, changing them from a flattened, fibroblastic appearance to a more rounded shape. We...... early adipocyte differentiation....

  9. Discoidin domain receptor 1 is activated independently of beta(1) integrin

    Vogel, W; Brakebusch, C; Fässler, R;


    Various types of collagen have been identified as potential ligands for the two mammalian discoidin domain receptor (DDR) tyrosine kinases, DDR1 and DDR2. It is presently unclear whether collagen-induced DDR receptor activation, which occurs with very slow kinetics, involves additional proteins...... blocking antibodies for alpha(2)beta(1) integrin or in cells with a targeted deletion of the beta(1) integrin gene. Finally, we show that overexpression of dominant negative DDR1 in the myoblast cell line C2C12 blocks cellular differentiation and the formation of myofibers....

  10. Fetal and adult hematopoietic stem cells require beta1 integrin function for colonizing fetal liver, spleen, and bone marrow

    Potocnik, A J; Brakebusch, C; Fässler, R


    Homing of hematopoietic stem cells (HSCs) into hematopoietic organs is a prerequisite for the establishment of hematopoiesis during embryogenesis and after bone marrow transplantation. We show that beta1 integrin-deficient HSCs from the para-aortic splanchnopleura and the fetal blood had hematoly......Homing of hematopoietic stem cells (HSCs) into hematopoietic organs is a prerequisite for the establishment of hematopoiesis during embryogenesis and after bone marrow transplantation. We show that beta1 integrin-deficient HSCs from the para-aortic splanchnopleura and the fetal blood had...... hematolymphoid differentiation potential in vitro and in fetal organ cultures but were unable to seed fetal and adult hematopoietic tissues. Adult beta1 integrin null HSCs isolated from mice carrying loxP-tagged beta1 integrin alleles and ablated for beta1 integrin expression by retroviral cre transduction...... failed to engraft irradiated recipient mice. Moreover, absence of beta1 integrin resulted in sequestration of HSCs in the circulation and their reduced adhesion to endothelioma cells. These findings define beta1 integrin as an essential adhesion receptor for the homing of HSCs....

  11. Recombinant laminin-8 (alpha(4)beta(1)gamma(1)). Production, purification,and interactions with integrins.

    Kortesmaa, J; Yurchenco, P; Tryggvason, K


    Laminins are a large family of heterotrimeric extracellular matrix glycoproteins that, in addition to having structural roles, take part in the regulation of processes such as cell migration, differentiation, and proliferation. The laminin alpha(4) chain is widely distributed both in adults and during development in tissues such as cardiac, skeletal and smooth muscle fibers, vascular endothelia, lungs, and in peripheral nerves. It can associate with laminin beta(1)/gamma(1) chains to form laminin-8 and with the beta(2)/gamma(1) chains to form laminin-9. Functional studies on these laminins have been hampered by poor availability of the protein in pure and soluble forms. To facilitate studies on laminin-8, recombinant laminin-8 was produced in a mammalian expression system, purified and shown to form native Y-shaped molecules in rotary shadowing electron microscopy. Integrins mediating cell adhesion to laminin-8 were identified using function-blocking mAbs. The integrin specificities were found to differ somewhat from that of laminin-1. Integrin alpha(6)beta(1) was found to be a major mediator of adhesion of HT-1080 and cultured capillary endothelial cells to laminin-8. Considering the expression patterns of laminin-8 and integrin alpha(6)beta(1) it is likely that the former is a ligand for the latter in vivo as well. PMID:10809728

  12. Dynamic expression of alpha 1 beta 1 and alpha 2 beta 1 integrin receptors by human vascular smooth muscle cells. Alpha 2 beta 1 integrin is required for chemotaxis across type I collagen-coated membranes.

    Skinner, M P; Raines, E W; Ross, R.


    Vascular smooth muscle cells (SMCs) in the media of normal arteries express alpha 1 beta 1 integrin with no detectable alpha 2 beta 1 as determined by immunocytochemistry. In contrast, immunoprecipitation of integrins expressed by human SMCs cultured from medial explants shows strong expression of alpha 2 beta 1 and no expression of alpha 1 beta 1. The apparent reciprocal expression of these two collagen and laminin receptors was confirmed by flow cytometric analysis of fluorescent labeled ce...

  13. Simultaneous changes in the function and expression of beta 1 integrins during the growth arrest of poorly differentiated colorectal cells (LISP-1

    R.A. Roela


    Full Text Available Cells usually lose adhesion and increase proliferation and migration during malignant transformation. Here, we studied how proliferation can affect the other two characteristics, which ultimately lead to invasion and metastasis. We determined the expression of ß1 integrins, as well as adhesion and migration towards laminin-1, fibronectin, collagens type I and type IV presented by LISP-1 colorectal cancer cells exposed to 2.5% dimethyl sulfoxide (DMSO, an agent capable of decreasing proliferation in this poorly differentiated colorectal cell line. Untreated cells (control, as shown by flow cytometry and monoclonal antibodies, expressed alpha2 (63.8 ± 11.3% positive cells, alpha3 (93.3 ± 7.0%, alpha5 (50.4 ± 12.0% and alpha6 (34.1 ± 4.9% integrins but not alpha1, alpha4, alphav or ß4. Cells adhered well to laminin-1 (73.4 ± 6.0% and fibronectin (40.0 ± 2.0% substrates but very little to collagens. By using blocking monoclonal antibodies, we showed that alpha2, alpha3 and alpha6 mediated laminin-1 adhesion, but neither alpha3 nor alpha5 contributed to fibronectin adherence. DMSO arrested cells at G0/G1 (control: 55.0 ± 2.4% vs DMSO: 70.7 ± 2.5% while simultaneously reducing alpha5 (24.2 ± 19% and alpha6 (14.3 ± 10.8% expression as well as c-myc mRNA (7-fold, the latter shown by Northern blotting. Although the adhesion rate did not change after exposure to DMSO, alpha3 and alpha5 played a major role in laminin-1 and fibronectin adhesion, respectively. Migration towards laminin-1, which was clearly increased upon exposure to DMSO (control: 6 ± 2 cells vs DMSO: 64 ± 6 cells, was blocked by an antibody against alpha6. We conclude that the effects of DMSO on LISP-1 proliferation were accompanied by concurrent changes in the expression and function of integrins, consequently modulating adhesion/migration, and revealing a complex interplay between function/expression and the proliferative state of cells.

  14. beta1-integrin-mediated signaling essentially contributes to cell survival after radiation-induced genotoxic injury

    Cordes, N; Seidler, J; Durzok, R; Geinitz, H; Brakebusch, C


    Integrin-mediated adhesion to extracellular matrix proteins confers resistance to radiation- or drug-induced genotoxic injury. To analyse the underlying mechanisms specific for beta1-integrins, wild-type beta1A-integrin-expressing GD25beta1A cells were compared to GD25beta1B cells, which express...... findings in tumor cells, human A-172 glioma cells were examined under the same conditions after siRNA-mediated silencing of beta1-integrins. We found that beta1A-integrin-mediated adhesion to fibronectin, collagen-III or beta1-IgG was essential for cell survival after radiation-induced genotoxic injury...... central role of beta1-integrins in Akt- and p130Cas/paxillin-mediated prosurvival signaling. These findings suggest beta1-integrins as critical regulators of cell survival after radiation-induced genotoxic injury. Elucidation of the molecular circuitry of prosurvival beta1-integrin-mediated signaling in...

  15. The fibronectin-binding integrins alpha5beta1 and alphavbeta3 differentially modulate RhoA-GTP loading, organization of cell matrix adhesions, and fibronectin fibrillogenesis

    Danen, Erik H J; Sonneveld, Petra; Brakebusch, Cord; Fassler, Reinhard; Sonnenberg, Arnoud


    We have studied the formation of different types of cell matrix adhesions in cells that bind to fibronectin via either alpha5beta1 or alphavbeta3. In both cases, cell adhesion to fibronectin leads to a rapid decrease in RhoA activity. However, alpha5beta1 but not alphavbeta3 supports high levels of...... RhoA activity at later stages of cell spreading, which are associated with a translocation of focal contacts to peripheral cell protrusions, recruitment of tensin into fibrillar adhesions, and fibronectin fibrillogenesis. Expression of an activated mutant of RhoA stimulates alphavbeta3-mediated...... fibrillogenesis. Despite the fact that alpha5beta1-mediated adhesion to the central cell-binding domain of fibronectin supports activation of RhoA, other regions of fibronectin are required for the development of alpha5beta1-mediated but not alphavbeta3-mediated focal contacts. Using chimeras of beta1 and beta3...

  16. Mycophenolate mofetil modulates adhesion receptors of the beta1 integrin family on tumor cells: impact on tumor recurrence and malignancy

    Beecken Wolf-Dietrich


    Full Text Available Abstract Background Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. Methods Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a, alpha2beta1 (CD49b, alpha3beta1 (CD49c, alpha4beta1 (CD49d, alpha5beta1 (CD49e, and alpha6beta1 (CD49f receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. Results Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. Conclusion We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype.

  17. Mycophenolate mofetil modulates adhesion receptors of the beta1 integrin family on tumor cells: impact on tumor recurrence and malignancy

    Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF) on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a), alpha2beta1 (CD49b), alpha3beta1 (CD49c), alpha4beta1 (CD49d), alpha5beta1 (CD49e), and alpha6beta1 (CD49f) receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype

  18. Alpha9beta1 integrin in melanoma cells can signal different adhesion states for migration and anchorage

    Lydolph, Magnus C; Morgan-Fisher, Marie; Høye, Anette M;


    Cell surface integrins are the primary receptors for cell migration on extracellular matrix, and exist in several activation states regulated in part by ectodomain conformation. The alpha9 integrin subunit, which pairs only with beta1, has specific roles in the immune system and may regulate cell......beta1 integrin- and Rho kinase-dependent focal adhesion and stress fibre formation, suggesting that the activation status of alpha9beta1 integrin was altered. The effect of manganese ions in promoting focal adhesion formation was reproduced by beta1 integrin activating antibody. The alpha9beta1...

  19. alpha 11beta 1 integrin recognizes the GFOGER sequence in interstitial collagens.

    Zhang, Wan-Ming; Kapyla, Jarmo; Puranen, J Santeri; Knight, C Graham; Tiger, Carl-Fredrik; Pentikainen, Olli T; Johnson, Mark S; Farndale, Richard W; Heino, Jyrki; Gullberg, Donald


    The integrins alpha(1)beta(1), alpha(2)beta(1), alpha(10)beta(1), and alpha(11)beta(1) are referred to as a collagen receptor subgroup of the integrin family. Recently, both alpha(1)beta(1) and alpha(2)beta(1) integrins have been shown to recognize triple-helical GFOGER (where single letter amino acid nomenclature is used, O = hydroxyproline) or GFOGER-like motifs found in collagens, despite their distinct binding specificity for various collagen subtypes. In the present study we have investigated the mechanism whereby the latest member in the integrin family, alpha(11)beta(1), recognizes collagens using C2C12 cells transfected with alpha(11) cDNA and the bacterially expressed recombinant alpha(11) I domain. The ligand binding properties of alpha(11)beta(1) were compared with those of alpha(2)beta(1). Mg(2+)-dependent alpha(11)beta(1) binding to type I collagen required micromolar Ca(2+) but was inhibited by 1 mm Ca(2+), whereas alpha(2)beta(1)-mediated binding was refractory to millimolar concentrations of Ca(2+). The bacterially expressed recombinant alpha(11) I domain preference for fibrillar collagens over collagens IV and VI was the same as the alpha(2) I domain. Despite the difference in Ca(2+) sensitivity, alpha(11)beta(1)-expressing cells and the alpha(11) I domain bound to helical GFOGER sequences in a manner similar to alpha(2)beta(1)-expressing cells and the alpha(2) I domain. Modeling of the alpha I domain-collagen peptide complexes could partially explain the observed preference of different I domains for certain GFOGER sequence variations. In summary, our data indicate that the GFOGER sequence in fibrillar collagens is a common recognition motif used by alpha(1)beta(1), alpha(2)beta(1), and also alpha(11)beta(1) integrins. Although alpha(10) and alpha(11) chains show the highest sequence identity, alpha(2) and alpha(11) are more similar with regard to collagen specificity. Future studies will reveal whether alpha(2)beta(1) and alpha(11)beta(1

  20. Beta1 integrin promotes but is not essential for metastasis of ras-myc transformed fibroblasts

    Brakebusch, C; Wennerberg, K; Krell, H W; Weidle, U H; Sallmyr, A; Johansson, S; Fässler, R


    integrin-expressing sublines. Tumors were induced by subcutaneous injection of GERM 11 cells and 3 independent beta1 integrin expressing sublines (GERM 116, 1A10, 2F2) into syngeneic mice. After 10 days tumors were surgically removed. While average weights of GERM 11 and GERM 116 tumors were similar...

  1. Beta1 integrin expression by podocytes is required to maintain glomerular structural integrity.

    Pozzi, Ambra; Jarad, George; Moeckel, Gilbert W; Coffa, Sergio; Zhang, Xi; Gewin, Leslie; Eremina, Vera; Hudson, Billy G; Borza, Dorin-Bogdan; Harris, Raymond C; Holzman, Lawrence B; Phillips, Carrie L; Fassler, Reinhard; Quaggin, Susan E; Miner, Jeffrey H; Zent, Roy


    Integrins are transmembrane heteromeric receptors that mediate interactions between cells and extracellular matrix (ECM). beta1, the most abundantly expressed integrin subunit, binds at least 12 alpha subunits. beta1 containing integrins are highly expressed in the glomerulus of the kidney; however their role in glomerular morphogenesis and maintenance of glomerular filtration barrier integrity is poorly understood. To study these questions we selectively deleted beta1 integrin in the podocyte by crossing beta1(flox/flox) mice with podocyte specific podocin-cre mice (pod-Cre), which express cre at the time of glomerular capillary formation. We demonstrate that podocyte abnormalities are visualized during glomerulogenesis of the pod-Cre;beta1(flox/flox) mice and proteinuria is present at birth, despite a grossly normal glomerular basement membrane. Following the advent of glomerular filtration there is progressive podocyte loss and the mice develop capillary loop and mesangium degeneration with little evidence of glomerulosclerosis. By 3 weeks of age the mice develop severe end stage renal failure characterized by both tubulointerstitial and glomerular pathology. Thus, expression of beta1 containing integrins by the podocyte is critical for maintaining the structural integrity of the glomerulus. PMID:18328474

  2. Signaling through urokinase and urokinase receptor in lung cancer cells requires interactions with beta1 integrins.

    Tang, Chi-Hui; Hill, Marla L; Brumwell, Alexis N; Chapman, Harold A; Wei, Ying


    The urokinase receptor (uPAR) is upregulated upon tumor cell invasion and correlates with poor lung cancer survival. Although a cis-interaction with integrins has been ascribed to uPAR, whether this interaction alone is critical to urokinase (uPA)- and uPAR-dependent signaling and tumor promotion is unclear. Here we report the functional consequences of point mutations of uPAR (H249A-D262A) that eliminate beta1 integrin interactions but maintain uPA binding, vitronectin attachment and association with alphaV integrins, caveolin and epidermal growth factor receptor. Disruption of uPAR interactions with beta1 integrins recapitulated previously reported findings with beta1-integrin-derived peptides that attenuated matrix-dependent ERK activation, MMP expression and in vitro migration by human lung adenocarcinoma cell lines. The uPAR mutant cells acquired enhanced capacity to adhere to vitronectin via uPAR-alphaVbeta5-integrin, rather than through the uPAR-alpha3beta1-integrin complex and they were unable to initiate uPA signaling to activate ERK, Akt or Stat1. In an orthotopic lung cancer model, uPAR mutant cells exhibited reduced tumor size compared with cells expressing wild-type uPAR. Taken together, the results indicate that uPAR-beta1-integrin interactions are essential to signals induced by integrin matrix ligands or uPA that support lung cancer cell invasion in vitro and progression in vivo. PMID:18940913

  3. Mouse egg integrin alpha 6 beta 1 functions as a sperm receptor.

    Almeida, E A; Huovila, A P; Sutherland, A E; Stephens, L E; Calarco, P G; Shaw, L M; Mercurio, A M; Sonnenberg, A; Primakoff, P; Myles, D G; White, J M


    Binding between sperm and egg plasma membranes is an essential step in fertilization. Whereas fertilin, a mammalian sperm surface protein, is involved in this crucial interaction, sperm receptors on the egg plasma membrane have not been identified. Because fertilin contains a predicted integrin ligand domain, we investigated the expression and function of integrin subunits in unfertilized mouse eggs. Polymerase chain reactions detected mRNAs for alpha 5, alpha 6, alpha v, beta 1, beta 3, and beta 5. Immunofluorescence revealed alpha 6 beta 1 and alpha v beta 3 on the plasma membrane. GoH3, a function-blocking anti-alpha 6 monoclonal antibody, abolished sperm binding, but a nonfunction-blocking anti-alpha 6 monoclonal antibody, a function-blocking anti-alpha v beta 3 polyclonal antibody, and an RGD peptide had no effect. Somatic cells bound sperm avidly, but only if they expressed alpha 6 beta 1. A peptide analog of the fertilin integrin ligand domain inhibited sperm binding to eggs and alpha 6 beta 1+ cells and diminished GoH3 staining of eggs. Our results indicate a novel role for the integrin alpha 6 beta 1 as a cell-cell adhesion receptor that mediates sperm-egg binding. PMID:7600577

  4. Integrin alpha3beta1, a novel receptor for alpha3(IV) noncollagenous domain and a trans-dominant Inhibitor for integrin alphavbeta3.

    Borza, Corina M; Pozzi, Ambra; Borza, Dorin-Bogdan; Pedchenko, Vadim; Hellmark, Thomas; Hudson, Billy G; Zent, Roy


    Exogenous soluble human alpha3 noncollagenous (NC1) domain of collagen IV inhibits angiogenesis and tumor growth. These biological functions are attributed to the binding of alpha3NC1 to integrin alphavbeta3. However, in some tumor cells that express integrin alphavbeta3, the alpha3NC1 domain does not inhibit proliferation, suggesting that integrin alphavbeta3 expression is not sufficient to mediate the anti-tumorigenic activity of this domain. Therefore, in the present study, we searched for novel binding receptors for the soluble alpha3NC1 domain in cells lacking alphavbeta3 integrin. In these cells, soluble alpha3NC1 bound integrin alpha3beta1; however, unlike alphavbeta3, alpha3beta1 integrin did not mediate cell adhesion to immobilized alpha3NC1 domain. Interestingly, in cells lacking integrin alpha3beta1, adhesion to the alpha3NC1 domain was enhanced due to activation of integrin alphavbeta3. These findings indicate that integrin alpha3beta1 is a receptor for the alpha3NC1 domain and transdominantly inhibits integrin alphavbeta3 activation. Thus integrin alpha3beta1, in conjunction with integrin alphavbeta3, modulates cellular responses to the alpha3NC1 domain, which may be pivotal in the mechanism underpinning its anti-angiogenic and anti-tumorigenic activities. PMID:16731529

  5. ADAM12-mediated focal adhesion formation is differently regulated by beta1 and beta3 integrins

    Thodeti, Charles Kumar; Frohlich, Camilla; Nielsen, Christian Kamp;


    ADAM12, adisintegrin and metalloprotease, has been demonstrated to be upregulated in human malignant tumors and to accelerate the malignant phenotype in a mouse model for breast cancer. ADAM12 is a substrate for beta1 integrins and may affect tumor and stromal cell behavior through its binding to...

  6. CD46 and beta1 integrin relocation in the sperm head during capacitation and acrosome reaction

    Šebková, N.; Frolíková, M.; Dvořáková-Hortová, Kateřina

    Madison: Society for the Study of Reproduction, 2015. s. 212. [48th Annual Meeting of the Society for the Study of reproduction. 18.06.2015-22.06.2015, San Juan] R&D Projects: GA ČR(CZ) GA14-05547S Institutional support: RVO:86652036 Keywords : CD46 * beta1 integrin * Proximity Ligation Assay * acrosome reaction Subject RIV: CE - Biochemistry

  7. Expression and functional importance of collagen-binding integrins, alpha 1 beta 1 and alpha 2 beta 1, on virus-activated T cells

    Andreasen, Susanne Ø; Thomsen, Allan R; Koteliansky, Victor E; Novobrantseva, Tatiana I; Sprague, Andrew G; de Fougerolles, Antonin R; Christensen, Jan P


    Adhesive interactions are crucial to cell migration into inflammatory sites. Using murine lymphocytic choriomeningitis virus as an Ag model system, we have investigated expression and function of collagen-binding integrins, alpha(1)beta(1) and alpha(2)beta(1), on activated and memory T cells. Using...... this system and MHC tetramers to define Ag-specific T cells, we demonstrate that contrary to being VLAs, expression of alpha(1)beta(1) and alpha(2)beta(1) can be rapidly induced on acutely activated T cells, that expression of alpha(1)beta(1) remains elevated on memory T cells, and that expression of...... alpha(1)beta(1) parallels that of viral-specific effector CD8(+) T cells (defined by tetramer and IFN-gamma staining). In an adoptive transfer model, mAb-mediated blockade of these integrins on activated effector and memory T cells inhibited Ag-specific delayed-type hypersensitivity responses; similar...

  8. Cellular growth and survival are mediated by beta 1 integrins in normal human breast epithelium but not in breast carcinoma

    Howlett, Anthony R; Bailey, Nina; Damsky, Caroline; Petersen, Ole W; Bissell, Mina J


    We previously established a rapid three-dimensional assay for discrimination of normal and malignant human breast epithelial cells using a laminin-rich reconstituted basement membrane. In this assay, normal epithelial cells differentiate into well-organized acinar structures whereas tumor cells fail to recapitulate this process and produce large, disordered colonies. The data suggest that breast acinar morphogenesis and differentiation is regulated by cell-extracellular matrix (ECM) interactions and that these interactions are altered in malignancy. Here, we investigated the role of ECM receptors (integrins) in these processes and report on the expression and function of potential laminin receptors in normal and tumorigenic breast epithelial cells. Immmunocytochemical analysis showed that normal and carcinoma cells in a three-dimensional substratum express profiles of integrins similar to normal and malignant breast tissues in situ. Normal cells express {alpha}1, {alpha}2, {alpha}3, {alpha}6, {beta}1 and {beta}4 integrin subunits, whereas breast carcinoma cells show variable losses, disordered expression, or down regulation of these subunits. Function-blocking experiments using inhibitory antiintegrin subunit antibodies showed a >5-fold inhibition of the formation of acinar structures by normal cells in the presence of either anti-{beta}1 or anti-{alpha}3 antibodies, whereas anti-{alpha}2 or -{alpha}6 had little or no effect. In experiments where collagen type I gels were used instead of basement membrane, acinar morphogenesis was blocked by anti-{beta}1 and -{alpha}2 antibodies but not by anti-{alpha}3. These data suggest a specificity of integrin utilization dependent on the ECM ligands encountered by the cell. The interruption of normal acinar morphogenesis by anti-integrin antibodies was associated with an inhibition of cell growth and induction of apoptosis. Function-blocking antibodies had no inhibitory effect on the rate of tumor cell growth, survival or

  9. Skin and hair follicle integrity is crucially dependent on beta 1 integrin expression on keratinocytes

    Brakebusch, C; Grose, R; Quondamatteo, F;


    developed severe hair loss due to a reduced proliferation of hair matrix cells and severe hair follicle abnormalities. Eventually, the malformed hair follicles were removed by infiltrating macrophages. The epidermis of the back skin became hyperthickened, the basal keratinocytes showed reduced expression of......, the integrity of the basement membrane surrounding the beta 1-deficient hair follicle was not affected. Finally, the dermis became fibrotic. These results demonstrate an important role of beta 1 integrins in hair follicle morphogenesis, in the processing of basement membrane components, in the...

  10. Lack of beta1 integrins in enteric neural crest cells leads to a Hirschsprung-like phenotype

    Breau, Marie A; Pietri, Thomas; Eder, Olivier;


    The enteric nervous system arises mainly from vagal and sacral neural crest cells that colonise the gut between 9.5 and 14 days of development in mice. Using the Cre-LoxP system, we removed beta1 integrins in the neural crest cells when they emerge from the neural tube. beta1-null enteric neural...... integrins are required for the villi innervation in the small intestine. Our findings highlight the crucial roles played by beta1 integrins at various steps of enteric nervous system development....

  11. beta 1 integrin inhibition dramatically enhances radiotherapy efficacy in human breast cancer xenografts

    Park, Catherine C.; Park, Catherine C.; Zhang, Hui J.; Yao, Evelyn S.; Park, Chong J.; Bissell, Mina J.


    {beta}1 integrin signaling has been shown to mediate cellular resistance to apoptosis after exposure to ionizing radiation (IR). Other signaling molecules that increase resistance include Akt, which promotes cell survival downstream of {beta}1 integrin signaling. We showed previously that {beta}1 integrin inhibitory antibodies, AIIB2, enhance apoptosis and decrease growth in human breast cancer cells in 3 dimensional laminin-rich extracellular matrix (3D lrECM) cultures and in vivo. Here we asked whether AIIB2 could synergize with IR to modify Akt-mediated IR resistance. We used 3D lrECM cultures to test the optimal combination of AIIB2 with IR treatment of two breast cancer cell lines, MCF-7 and HMT3522-T4-2, as well as T4-2 myr-Akt breast cancer colonies or HMT3522-S-1, which form normal organotypic structures in 3D lrECM. Colonies were assayed for apoptosis and {beta}1 integrin/Akt signaling pathways were evaluated using western blot. In addition, mice bearing MCF-7 xenografts were used to validate the findings in 3D lrECM. We report that AIIB2 increased apoptosis optimally post-IR by down regulating Akt in breast cancer colonies in 3D lrECM. In vivo, addition of AIIB2 after IR significantly enhanced tumor growth inhibition and apoptosis compared to either treatment alone. Remarkably, the degree of tumor growth inhibition using AIIB2 plus 2 Gy radiation was similar to that of 8 Gy alone. We showed previously that AIIB2 had no discernible toxicity in mice; here, its addition allowed for a significant reduction in the IR dose that was necessary to achieve comparable growth inhibition and apoptosis in breast cancer xenografts in vivo.

  12. A preliminary optical and electron microscopic study of the beta(1) integrin distribution pattern of human osteosarcoma-derived cells.

    Banai, Kiarash; Brady, Ken; McDonald, Fraser


    Immunogold labelling was used to study the organisation of the beta(1) integrins on osteosarcoma-derived osteoblasts (Saos-2 and MG-63). Monolayers of cells were prepared in multiwell culture plates on both uncovered and collagen-covered coverslips, and beta(1) integrins were primarily labelled using mouse monoclonal antibodies to beta(1) integrins. Indirect immunofluorescence labels using an anti-mouse fluorescein-conjugated goat antibody showed an even distribution of the beta(1) integrins on the cell membranes of all cell types used. A concentration of 2 microg/ml of the primary antibodies and a 1:100 dilution of the secondary antibodies were determined as the optimal concentration for labelling to use with indirect localisation of the primary antibodies gold conjugated to goat anti-mouse antibodies and viewed under an electron microscope. Ten nanometre gold particles were used for transmission electron microscopy (TEM) and 40 nm gold particles for scanning electron microscopy. TEM showed that beta(1) integrins were mainly clustered on the cell membrane processes with less labelling on the cell membranes themselves. The distribution of beta(1) integrins on osteosarcoma cells supports the concept that integrins may function by forming focal adhesions at the site of the cytoplasmic membrane processes. PMID:15241608

  13. Prolyl hydroxylation of collagen type I is required for efficient binding to integrin alpha 1 beta 1 and platelet glycoprotein VI but not to alpha 2 beta 1.

    Perret, Stéephanie; Eble, Johannes A; Siljander, Pia R-M; Merle, Christine; Farndale, Richard W; Theisen, Manfred; Ruggiero, Florence


    Collagen is a potent adhesive substrate for cells, an event essentially mediated by the integrins alpha 1 beta 1 and alpha 2 beta 1. Collagen fibrils also bind to the integrin alpha 2 beta 1 and the platelet receptor glycoprotein VI to activate and aggregate platelets. The distinct triple helical recognition motifs for these receptors, GXOGER and (GPO)n, respectively, all contain hydroxyproline. Using unhydroxylated collagen I produced in transgenic plants, we investigated the role of hydroxyproline in the receptor-binding properties of collagen. We show that alpha 2 beta 1 but not alpha 1 beta 1 mediates cell adhesion to unhydroxylated collagen. Soluble recombinant alpha 1 beta 1 binding to unhydroxylated collagen is considerably reduced compared with bovine collagens, but binding can be restored by prolyl hydroxylation of recombinant collagen. We also show that platelets use alpha 2 beta 1 to adhere to the unhydroxylated recombinant molecules, but the adhesion is weaker than on fully hydroxylated collagen, and the unhydroxylated collagen fibrils fail to aggregate platelets. Prolyl hydroxylation is thus required for binding of collagen to platelet glycoprotein VI and to cells by alpha 1 beta 1. These observations give new insights into the molecular basis of collagen-receptor interactions and offer new selective applications for the recombinant unhydroxylated collagen I. PMID:12771137

  14. Loss of integrin alpha1beta1 ameliorates Kras-induced lung cancer.

    Macias-Perez, Ines; Borza, Corina; Chen, Xiwu; Yan, Xuexian; Ibanez, Raquel; Mernaugh, Glenda; Matrisian, Lynn M; Zent, Roy; Pozzi, Ambra


    The collagen IV binding receptor integrin alpha1beta1 has been shown to regulate lung cancer due to its proangiogenic properties; however, it is unclear whether this receptor also plays a direct role in promoting primary lung tumors. To investigate this possibility, integrin alpha1-null mice were crossed with KrasLA2 mice that carry an oncogenic mutation of the Kras gene (G12D) and develop spontaneous primary tumors with features of non-small cell lung cancer. We provide evidence that KrasLA2/alpha1-null mice have a decreased incidence of primary lung tumors and longer survival compared with KrasLA2/alpha1 wild-type controls. Tumors from KrasLA2/alpha1-null mice were also smaller, less vascularized, and exhibited reduced cell proliferation and increased apoptosis, as determined by proliferating cell nuclear antigen and terminal deoxynucleotidyl-transferase-mediated dUTP nick-end staining, respectively. Moreover, tumors from the KrasLA2/alpha1-null mice showed diminished extracellular signal-regulated kinase (ERK) but enhanced p38 mitogen-activated protein kinase activation. Primary lung tumor epithelial cells isolated from KrasLA2/alpha1-null mice showed a significant decrease in anchorage-independent colony formation, collagen-mediated cell proliferation, ERK activation, and, most importantly, tumorigenicity when injected into nude mice compared with KrasLA2/alpha1 wild-type tumor cells. These results indicate that loss of the integrin alpha1 subunit decreases the incidence and growth of lung epithelial tumors initiated by oncogenic Kras, suggesting that both Kras and integrin alpha1beta1 cooperate to drive the growth of non-small cell lung cancer in vivo. PMID:18676835

  15. Blood platelets contain and secrete laminin-8 (alpha4beta1gamma1) and adhere to laminin-8 via alpha6beta1 integrin.

    Geberhiwot, T; Ingerpuu, S; Pedraza, C; Neira, M; Lehto, U; Virtanen, I; Kortesmaa, J; Tryggvason, K; Engvall, E; Patarroyo, M


    Laminins, a family of heterotrimeric proteins with cell adhesive/signaling properties, are characteristic components of basement membranes of vasculature and tissues. In the present study, permeabilized platelets were found to react with a monoclonal antibody to laminin gamma1 chain by immunofluorescence. In Western blot analysis of platelet lysates, several monoclonal antibodies to gamma1 and beta1 laminin chains recognized 220- to 230-kDa polypeptides, under reducing conditions, and a structure with much slower electrophoretic mobility under nonreducing conditions. Immunoaffinity purification on a laminin beta1 antibody-Sepharose column yielded polypeptides of 230, 220, 200, and 180 kDa from platelet lysates. In the purified material, mAbs to beta1 and gamma1 reacted with the two larger polypeptides, while affinity-purified rabbit antibodies to laminin alpha4 chain recognized the smallest polypeptide. Identity of the polypeptides was confirmed by microsequencing. One million platelets contained on average 1 ng of laminin (approximately 700 molecules per cell), of which 20-35% was secreted within minutes after stimulation with either thrombin or phorbol ester. Platelets adhered to plastic surfaces coated with the purified platelet laminin, and this process was largely inhibited by antibodies to beta1 and alpha6 integrin chains. We conclude that platelets contain and, following activation, secrete laminin-8 (alpha4beta1gamma1) and that the cells adhere to the protein by using alpha6beta1 integrin. PMID:10585296

  16. Tumor cell adhesion to endothelial cells is increased by endotoxin via an upregulation of beta-1 integrin expression.

    Andrews, E J


    BACKGROUND: Recent studies have demonstrated that metastatic disease develops from tumor cells that adhere to endothelial cells and proliferate intravascularly. The beta-1 integrin family and its ligand laminin have been shown to be important in tumor-to-endothelial cell adhesion. Lipopolysaccharide (LPS) has been implicated in the increased metastatic tumor growth that is seen postoperatively. We postulated that LPS increases tumor cell expression of beta-1 integrins and that this leads to increased adhesion. METHODS: The human metastatic colon cancer cell line LS174T was labeled with an enhanced green fluorescent protein (eGFP) using retroviral transfection. Cell cultures were treated with LPS for 1, 2, and 4 h (n = 6 each) and were subsequently cocultured for 30 or 120 min with confluent human umbilical vein endothelial cells (HUVECs), to allow adherence. Adherent tumor cells were counted using fluorescence microscopy. These experiments were carried out in the presence or absence of a functional blocking beta-1 integrin monoclonal antibody (4B4). Expression of beta-1 integrin and laminin on tumor and HUVECs was assessed using flow cytometric analysis. Tumor cell NF-kappaB activation after incubation with LPS was measured. RESULTS: Tumor cell and HUVEC beta-1 integrin expression and HUVEC expression of laminin were significantly (P < 0.05) enhanced after incubation with LPS. Tumor cell adhesion to HUVECs was significantly increased. Addition of the beta-1 integrin blocking antibody reduced tumor cell adhesion to control levels. LPS increased tumor cell NF-kappaB activation. CONCLUSIONS: Exposure to LPS increases tumor cell adhesion to the endothelium through a beta-1 integrin-mediated pathway that is NF-kappaB dependent. This may provide a target for immunotherapy directed at reducing postoperative metastatic tumor growth.

  17. Interactions of the integrin subunit beta1A with protein kinase B/Akt, p130Cas and paxillin contribute to regulation of radiation survival

    Seidler, Julia; Durzok, Rita; Brakebusch, Cord; Cordes, Nils


    BACKGROUND AND PURPOSE: Cell adhesion-mediated radioresistance is a common phenomenon particularly relevant in tumor cells, which might hamper anticancer therapies. To analyze the role of adhesion-mediating beta1-integrins, stably transfected functional beta1A-integrin-expressing GD25beta1A and G...

  18. Beta 1 integrin predicts survival in breast cancer: a clinicopathological and immunohistochemical study

    dos Santos Petra


    Full Text Available Abstract Background The main focus of several studies concerned with cancer progression and metastasis is to analyze the mechanisms that allow cancer cells to interact and quickly adapt with their environment. Integrins, a family of transmembrane glycoproteins, play a major role in invasive and metastatic processes. Integrins are involved in cell adhesion in both cell-extracellular matrix and cell-cell interactions, and particularly, β1 integrin is involved in proliferation and differentiation of cells in the development of epithelial tissues. This work aimed to investigate the putative role of β1 integrin expression on survival and metastasis in patients with breast invasive ductal carcinoma (IDC. In addition, we compared the expression of β1 integrin in patients with ductal carcinoma in situ (DCIS. Methods Through tissue microarray (TMA slides containing 225 samples of IDC and 67 samples of DCIS, β1 integrin expression was related with several immunohistochemical markers and clinicopathologic features of prognostic significance. Results β1 integrin was overexpressed in 32.8% of IDC. In IDC, β1 integrin was related with HER-2 (p = 0.019 and VEGF (p = 0.011 expression and it had a significant relationship with metastasis and death (p = 0.001 and p = 0.05, respectively. Kaplan-Meier survival analysis showed that the overexpression of this protein is very significant (p = 0.002 in specific survival (number of months between diagnosis and death caused by the disease. There were no correlation between IDC and DCIS (p = 0.559 regarding β1 integrin expression. Conclusions Considering that the expression of β1 integrin in breast cancer remains controversial, specially its relation with survival of patients, our findings provide further evidence that β1 integrin can be a marker of poor prognosis in breast cancer. Virtual slides The virtual slide(s for this article can be found here: http

  19. Differential expression of integrins and laminin-5 in normal oral epithelia

    Thorup, A K; Dabelsteen, Erik; Schou, S;


    /parabasal cells in keratinized epithelia, whereas there was increased suprabasal expression in nonkeratinized mucosa. These results indicate inhomogeneity in the basal cell population of oral squamous epithelia and differential expression of integrins, which may reflect differences in the underlying stroma......beta 1 and beta 4 integrins are receptors on epithelial cells mediating cell-extracellular matrix adhesion. Furthermore, alpha 2 beta 1 and alpha 3 beta 1 contribute to cell-cell adhesion. Laminin-5 in epithelial basement membranes (BMs) is a ligand for alpha 6 beta 4 and alpha 3 beta 1. Expression...... of different integrins and laminin-5 was studied in oral epithelium to characterize regional variations in these adhesion molecules. Monoclonal antibodies directed against alpha 2-alpha 6 beta 1/alpha 6 beta 4 and laminin-5 were examined in cryopreserved biopsies of normal mucosa by...

  20. Role of the beta1-integrin cytoplasmic tail in mediating invasin-promoted internalization of Yersinia

    Gustavsson, Anna; Armulik, Annika; Brakebusch, Cord;


    1B or different mutants of the beta1A subunit was used. Both beta1A and beta1B bound to invasin-expressing bacteria, but only beta1A was able to mediate internalization of the bacteria. The cytoplasmic region of beta1A, differing from beta1B, contains two NPXY motifs surrounding a double threonine...

  1. Increased expression of integrin alpha2 and abnormal response to TGF-beta1 in hereditary gingival fibromatosis.

    Zhou, J.; Meng, L.; Ye, X.Q.; Hoff, J.W. von den; Bian, Z.


    OBJECTIVE: To investigate the possible correlation between integrin alpha1, alpha2, and beta1 expression and excessive collagen synthesis in fibroblasts from 3 unrelated Chinese families with hereditary gingival fibromatosis (HGF). DESIGN: Gingival fibroblasts from three Chinese HGF patients and thr

  2. Integrin {beta}1-dependent invasive migration of irradiation-tolerant human lung adenocarcinoma cells in 3D collagen matrix

    Ishihara, Seiichiro [Transdisciplinary Life Science Course, Faculty of Advanced Life Science, Hokkaido University, N10-W8, Kita-ku, Sapporo 060-0810 (Japan); Haga, Hisashi, E-mail: [Transdisciplinary Life Science Course, Faculty of Advanced Life Science, Hokkaido University, N10-W8, Kita-ku, Sapporo 060-0810 (Japan); Yasuda, Motoaki [Department of Oral Pathobiological Science, Graduate School of Dental Medicine, Hokkaido University, N13-W7, Kita-ku, Sapporo 060-8586 (Japan); Mizutani, Takeomi; Kawabata, Kazushige [Transdisciplinary Life Science Course, Faculty of Advanced Life Science, Hokkaido University, N10-W8, Kita-ku, Sapporo 060-0810 (Japan); Shirato, Hiroki [Department of Radiology, Hokkaido University Graduate School of Medicine, N15-W7, Kita-ku, Sapporo 060-8638 (Japan); Nishioka, Takeshi [Department of Biomedical Sciences and Engineering, Faculty of Health Sciences, Hokkaido University, N12-W5, Kita-ku, Sapporo 060-0812 (Japan)


    Radiotherapy is one of the effective therapies used for treating various malignant tumors. However, the emergence of tolerant cells after irradiation remains problematic due to their high metastatic ability, sometimes indicative of poor prognosis. In this study, we showed that subcloned human lung adenocarcinoma cells (A549P-3) that are irradiation-tolerant indicate high invasive activity in vitro, and exhibit an integrin {beta}1 activity-dependent migratory pattern. In collagen gel overlay assay, majority of the A549P-3 cells displayed round morphology and low migration activity, whereas a considerable number of A549P-3IR cells surviving irradiation displayed a spindle morphology and high migration rate. Blocking integrin {beta}1 activity reduced the migration rate of A549P-3IR cells and altered the cell morphology allowing them to assume a round shape. These results suggest that the A549P-3 cells surviving irradiation acquire a highly invasive integrin {beta}1-dependent phenotype, and integrin {beta}1 might be a potentially effective therapeutic target in combination with radiotherapy.

  3. Integrins (alpha7beta1) in muscle function and survival. Disrupted expression in merosin-deficient congenital muscular dystrophy

    Vachon, P H; Xu, H; Liu, L;


    Mutations in genes coding for dystrophin, for alpha, beta, gamma, and delta-sarcoglycans, or for the alpha2 chain of the basement membrane component merosin (laminin-2/4) cause various forms of muscular dystrophy. Analyses of integrins showed an abnormal expression and localization of alpha7beta1...

  4. Use of synthetic peptides to locate novel integrin alpha2beta1-binding motifs in human collagen III.

    Raynal, Nicolas; Hamaia, Samir W; Siljander, Pia R-M; Maddox, Ben; Peachey, Anthony R; Fernandez, Rafael; Foley, Loraine J; Slatter, David A; Jarvis, Gavin E; Farndale, Richard W


    A set of 57 synthetic peptides encompassing the entire triplehelical domain of human collagen III was used to locate binding sites for the collagen-binding integrin alpha(2)beta(1). The capacity of the peptides to support Mg(2+)-dependent binding of several integrin preparations was examined. Wild-type integrins (recombinant alpha(2) I-domain, alpha(2)beta(1) purified from platelet membranes, and recombinant soluble alpha(2)beta(1) expressed as an alpha(2)-Fos/beta(1)-Jun heterodimer) bound well to only three peptides, two containing GXX'GER motifs (GROGER and GMOGER, where O is hydroxyproline) and one containing two adjacent GXX'GEN motifs (GLKGEN and GLOGEN). Two mutant alpha(2) I-domains were tested: the inactive T221A mutant, which recognized no peptides, and the constitutively active E318W mutant, which bound a larger subset of peptides. Adhesion of activated human platelets to GER-containing peptides was greater than that of resting platelets, and HT1080 cells bound well to more of the peptides compared with platelets. Binding of cells and recombinant proteins was abolished by anti-alpha(2) monoclonal antibody 6F1 and by chelation of Mg(2+). We describe two novel high affinity integrin-binding motifs in human collagen III (GROGER and GLOGEN) and a third motif (GLKGEN) that displays intermediate activity. Each motif was verified using shorter synthetic peptides. PMID:16326707

  5. Mechanotransduction molecules in the plant gravisensory response: amyloplast/statolith membranes contain a beta 1 integrin-like protein

    Lynch, T. M.; Lintilhac, P. M.; Domozych, D.


    It has been hypothesized that the sedimentation of amyloplasts within root cap cells is the primary event in the plant gravisensory-signal transduction cascade. Statolith sedimentation, with its ability to generate weighty mechanical signals, is a legitimate means for organisms to discriminate the direction of the gravity vector. However, it has been demonstrated that starchless mutants with reduced statolith densities maintain some ability to sense gravity, calling into question the statolith sedimentation hypothesis. Here we report on the presence of a beta 1 integrin-like protein localized inside amyloplasts of tobacco NT-1 suspension culture, callus cells, and whole-root caps. Two different antibodies to the beta 1 integrin, one to the cytoplasmic domain and one to the extracellular domain, localize in the vicinity of the starch grains within amyloplasts of NT-1. Biochemical data reveals a 110-kDa protein immunoprecipitated from membrane fractions of NT-1 suspension culture indicating size homology to known beta 1 integrin in animals. This study provides the first direct evidence for the possibility of integrin-mediated signal transduction in the perception of gravity by higher plants. An integrin-mediated pathway, initiated by starch grain sedimentation within the amyloplast, may provide the signal amplification necessary to explain the gravitropic response in starch-depleted cultivars.

  6. The cysteine-rich domain of human ADAM 12 supports cell adhesion through syndecans and triggers signaling events that lead to beta1 integrin-dependent cell spreading

    Iba, K; Albrechtsen, R; Gilpin, B;


    spread on ADAM 12. However, spreading could be efficiently induced by the addition of either 1 mM Mn(2+) or the beta1 integrin-activating monoclonal antibody 12G10, suggesting that in these carcinoma cells, the ADAM 12-syndecan complex fails to modulate the function of beta1 integrin.......-dependent manner attach to ADAM 12 via members of the syndecan family. After binding to syndecans, mesenchymal cells spread and form focal adhesions and actin stress fibers. Integrin beta1 was responsible for cell spreading because function-blocking monoclonal antibodies completely inhibited cell spreading, and...... chondroblasts lacking beta1 integrin attached but did not spread. These data suggest that mesenchymal cells use syndecans as the initial receptor for the ADAM 12 cysteine-rich domain-mediated cell adhesion, and then the beta1 integrin to induce cell spreading. Interestingly, carcinoma cells attached but did not...

  7. Rhodocytin (aggretin) activates platelets lacking alpha(2)beta(1) integrin, glycoprotein VI, and the ligand-binding domain of glycoprotein Ibalpha

    Bergmeier, W; Bouvard, D; Eble, J A;


    collagen may activate platelets by a similar mechanism. In contrast to these findings, we provided evidence that rhodocytin does not bind to alpha(2)beta(1) integrin. Here we show that the Cre/loxP-mediated loss of beta(1) integrin on mouse platelets has no effect on rhodocytin-induced platelet activation......Although alpha(2)beta(1) integrin (glycoprotein Ia/IIa) has been established as a platelet collagen receptor, its role in collagen-induced platelet activation has been controversial. Recently, it has been demonstrated that rhodocytin (also termed aggretin), a snake venom toxin purified from the......, excluding an essential role of alpha(2)beta(1) integrin in this process. Furthermore, proteolytic cleavage of the 45-kDa N-terminal domain of glycoprotein (GP) Ibalpha either on normal or on beta(1)-null platelets had no significant effect on rhodocytin-induced platelet activation. Moreover, mouse platelets...

  8. Function of glycoprotein VI and integrin alpha2beta1 in the procoagulant response of single, collagen-adherent platelets.

    Heemskerk, J W; Siljander, P; Vuist, W M; Breikers, G; Reutelingsperger, C P; Barnes, M J; Knight, C G; Lassila, R; Farndale, R W


    Various collagen-based materials were used to assess the structural requirements of collagen for inducing the procoagulant response of adhering platelets, as well as the collagen receptors involved. Cross-linked or monomeric collagen-related peptide (CRP), Gly-Cys-Hyp-(Gly-Pro-Hyp)10-Gly-Cys-Hyp-Gly was highly adhesive for platelets in a glycoprotein VI-(GpVI-)dependent manner. Adhesion was followed by a prolonged increase in cytosolic [Ca2+]i, formation of membrane blebs, exposure of phosphatidylserine (PS) and generation of prothrombinase-stimulating activity. Fibrils of type-I collagen were less adhesive but, once adhered, many of the platelets presented a full procoagulant response. Monomeric type-I collagen was unable to support adhesion, unless Mg(2+)-dependent integrin alpha2beta1 interactions were facilitated by omission of Ca2+ ions. With all surfaces, however, post-addition of CaCl2 to adhering platelets resulted in a potent Ca(2+)-influx signal, followed by PS exposure and bleb formation. The procoagulant response elicited by binding to CRP was inhibited by anti-GpVI Fab fragments, but not by impeding integrin alpha2beta1-mediated events. With fibrillar collagen, it was inhibited by blocking either the GpVI- or integrin alpha2beta1-mediated interactions. This suggests that the triple-helical Gly-Pro-Hyp repeat in CRP and analogous sequences in fibrillar collagen stimulate the procoagulant response of adherent platelets by acting as ligands for GpVI. Influx of Ca2+ is required for this response, and adhesion via integrin alpha2beta1 serves to potentiate the signaling effects of GpVI. PMID:10365754

  9. Antimigratory effect of TK1-2 is mediated in part by interfering with integrin alpha2beta1.

    Kim, Hyun-Kyung; Oh, Dae-Shik; Lee, Sang-Bae; Ha, Jung-Min; Joe, Young Ae


    The recombinant two kringle domain of human tissue-type plasminogen activator (TK1-2) has been shown to inhibit endothelial cell proliferation, angiogenesis, and tumor cell growth despite of sharing a low amino acid sequence homology with angiostatin. Here, we explored a possible inhibitory mechanism of action of TK1-2 by focusing on antimigratory effect. TK1-2 effectively inhibited endothelial cell migration induced by basic fibroblast growth factor or vascular endothelial growth factor in a dose-dependent manner and tube formation on Matrigel. It blocked basic fibroblast growth factor-induced or vascular endothelial growth factor-induced phosphorylation of extracellular signal-regulated kinase 1/2 and formation of actin stress fibers and focal adhesions. Interestingly, TK1-2 alone induced the weak phosphorylation of focal adhesion kinase, whereas it inhibited focal adhesion kinase phosphorylation induced by growth factors. When immobilized, TK1-2 promoted adhesion and spreading of endothelial cells compared with bovine serum albumin. However, treatment with anti-alpha(2)beta(1) blocking antibody markedly diminished endothelial cell adhesion to immobilized TK1-2 compared with anti-alpha(v)beta(3) or anti-alpha(5)beta(1) antibody. Pretreatment of soluble TK1-2 also altered the binding level of anti-alpha(2)beta(1) antibody to endothelial cells in fluorescence-activated cell sorting analysis. Indeed, a blocking antibody against integrin alpha(2)beta(1) or knocking down of integrin alpha(2) expression prevented the inhibitory effect of TK1-2 in cell migration. Therefore, these results suggest that TK1-2 inhibits endothelial cell migration through inhibition of signaling and cytoskeleton rearrangement in part by interfering with integrin alpha(2)beta(1). PMID:18645023

  10. The Effect of dcEFs on migration behavior of A549 cells and Integrin beta1 expression

    Yunjie WANG


    Full Text Available Background and objective The effect of direct-current electric fields (dcEFs on cells attracted extensive attention. Moreover the metastasis and its potential are considered to be related to dcEFs. The aim is to study the effect of dcEFs on migration behavior of A549 cells, Integrin ?1 and its signal pathways. Methods According to exposure to 5 V/cm dcEFs or not and the time of exposure, the A549 cells were divided into 4 groups. Images were taken per 5 min within 2 h to recode the migration of the cells. The data of results were analyzed statistically. Results Most of A549cells exposed to the dcEFs aligned and elongated perpendicularly to the electric field lines and migrated to the cathode continually during 2 h. On the contrary, cells unexposed to dcEFs showed slightly random movements. Immunofluorescence showed that Integrin ?1 on plasma membrane polarized to the cathode of the dcEFs. Western blot showed that Integrin beta1 downstream signal pathways p-FAK and p-ERK were overexpressed in the dcEFs. Conclusion A549 cells have a galvanotatic feature of cathodal directed migration while exposed to the dcEFs. The polarization of Integrin beta1 and the promotion of its downstream signal pathways may play an important roles in the galvanotaxis of A549 cells.

  11. Inhibiting Vimentin or beta 1-integrin Reverts Prostate Tumor Cells in IrECM and Reduces Tumor Growth

    Zhang, Xueping; Fournier, Marcia V.; Ware, Joy L.; Bissell, Mina J.; Zehner, Zendra E.


    Prostate epithelial cells grown embedded in laminin-rich extracellular matrix (lrECM) undergo morphological changes that closely resemble their architecture in vivo. In this study, growth characteristics of three human prostate epithelial sublines derived from the same cellular lineage, but displaying different tumorigenic and metastatic properties in vivo, were assessed in three-dimensional (3D) lrECM gels. M12, a highly tumorigenic and metastatic subline, was derived from the parental prostate epithelial P69 cell line by selection in nude mice and found to contain a deletion of 19p-q13.1. The stable reintroduction of an intact human chromosome 19 into M12 resulted in a poorly tumorigenic subline, designated F6. When embedded in lrECM gels, the nontumorigenic P69 line produced acini with clearly defined lumena. Immunostaining with antibodies to {beta}-catenin, E-cadherin or {alpha}6-, {beta}4- and {beta}1-integrins showed polarization typical of glandular epithelium. In contrast, the metastatic M12 subline produced highly disorganized cells with no evidence of polarization. The F6 subline reverted to acini-like structures exhibiting basal polarity marked with integrins. Reducing either vimentin levels via siRNA interference or {beta}1-integrin expression by the addition of the blocking antibody, AIIB2, reorganized the M12 subline into forming polarized acini. The loss of vimentin significantly reduced M12-Vim tumor growth when assessed by subcutaneous injection in athymic mice. Thus, tumorigenicity in vivo correlated with disorganized growth in 3D lrECM gels. These studies suggest that the levels of vimentin and {beta}1-integrin play a key role in the homeostasis of the normal acini in prostate and that their dysregulation may lead to tumorigenesis.

  12. Plasmin-induced migration requires signaling through protease-activated receptor 1 and integrin alpha(9)beta(1).

    Majumdar, Mousumi; Tarui, Takehiko; Shi, Biao; Akakura, Nobuaki; Ruf, Wolfram; Takada, Yoshikazu


    Plasmin is a major extracellular protease that elicits intracellular signals to mediate platelet aggregation, chemotaxis of peripheral blood monocytes, and release of arachidonate and leukotriene from several cell types in a G protein-dependent manner. Angiostatin, a fragment of plasmin(ogen), is a ligand and an antagonist for integrin alpha(9)beta(1). Here we report that plasmin specifically interacts with alpha(9)beta(1) and that plasmin induces of cells expressing migration recombinant alpha(9)beta(1) (alpha(9)-Chinese hamster ovary (CHO) cells). Migration was dependent on an interaction of the kringle domains of plasmin with alpha(9)beta(1) as well as the catalytic activity of plasmin. Angiostatin, representing the kringle domains of plasmin, alone did not induce the migration of alpha(9)-CHO cells, but simultaneous activation of the G protein-coupled protease-activated receptor (PAR)-1 with an agonist peptide induced the migration on angiostatin, whereas PAR-2 or PAR-4 agonist peptides were without effect. Furthermore, a small chemical inhibitor of PAR-1 (RWJ 58259) and a palmitoylated PAR-1-blocking peptide inhibited plasmin-induced migration of alpha(9)-CHO cells. These results suggest that plasmin induces migration by kringle-mediated binding to alpha(9)beta(1) and simultaneous proteolytic activation of PAR-1. PMID:15247268

  13. Cellular partitioning of beta-1 integrins and their phosphorylated forms is altered after transformation by Rous sarcoma virus or treatment with cytochalasin D.

    Haimovich, B; Aneskievich, B J; Boettiger, D


    A sequential extraction procedure of 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate (CHAPS) buffer followed by RIPA or Laemmli sample buffer was developed to define two distinct subpopulations of beta-1 integrins in primary chicken embryo fibroblasts. Extraction of cells in culture revealed an association of adhesion plaque-localized integrin with the CHAPS-insoluble fraction. Phosphorylated integrins were found in both fractions, but the specific phosphorylation was 12-fold high...

  14. Integrin alpha1beta1 regulates epidermal growth factor receptor activation by controlling peroxisome proliferator-activated receptor gamma-dependent caveolin-1 expression.

    Chen, Xiwu; Whiting, Carrie; Borza, Corina; Hu, Wen; Mont, Stacey; Bulus, Nada; Zhang, Ming-Zhi; Harris, Raymond C; Zent, Roy; Pozzi, Ambra


    Integrin alpha1beta1 negatively regulates the generation of profibrotic reactive oxygen species (ROS) by inhibiting epidermal growth factor receptor (EGFR) activation; however, the mechanism by which it does this is unknown. In this study, we show that caveolin-1 (Cav-1), a scaffolding protein that binds integrins and controls growth factor receptor signaling, participates in integrin alpha1beta1-mediated EGFR activation. Integrin alpha1-null mesangial cells (MCs) have reduced Cav-1 levels, and reexpression of the integrin alpha1 subunit increases Cav-1 levels, decreases EGFR activation, and reduces ROS production. Downregulation of Cav-1 in wild-type MCs increases EGFR phosphorylation and ROS synthesis, while overexpression of Cav-1 in the integrin alpha1-null MCs decreases EGFR-mediated ROS production. We further show that integrin alpha1-null MCs have increased levels of activated extracellular signal-regulated kinase (ERK), which leads to reduced activation of peroxisome proliferator-activated receptor gamma (PPARgamma), a transcription factor that positively regulates Cav-1 expression. Moreover, activation of PPARgamma or inhibition of ERK increases Cav-1 levels in the integrin alpha1-null MCs. Finally, we show that glomeruli of integrin alpha1-null mice have reduced levels of Cav-1 and activated PPARgamma but increased levels of phosphorylated EGFR both at baseline and following injury. Thus, integrin alpha1beta1 negatively regulates EGFR activation by positively controlling Cav-1 levels, and the ERK/PPARgamma axis plays a key role in regulating integrin alpha1beta1-dependent Cav-1 expression and consequent EGFR-mediated ROS production. PMID:20368353

  15. Endotoxin/lipopolysaccharide activates NF-kappa B and enhances tumor cell adhesion and invasion through a beta 1 integrin-dependent mechanism.

    Wang, Jiang Huai


    Beta(1) integrins play a crucial role in supporting tumor cell attachment to and invasion into the extracellular matrix. Endotoxin\\/LPS introduced by surgery has been shown to enhance tumor metastasis in a murine model. Here we show the direct effect of LPS on tumor cell adhesion and invasion in extracellular matrix proteins through a beta(1) integrin-dependent pathway. The human colorectal tumor cell lines SW480 and SW620 constitutively expressed high levels of the beta(1) subunit, whereas various low levels of alpha(1), alpha(2), alpha(4), and alpha(6) expression were detected. SW480 and SW620 did not express membrane-bound CD14; however, LPS in the presence of soluble CD14 (sCD14) significantly up-regulated beta(1) integrin expression; enhanced tumor cell attachment to fibronectin, collagen I, and laminin; and strongly promoted tumor cell invasion through the Matrigel. Anti-beta(1) blocking mAbs (4B4 and 6S6) abrogated LPS- plus sCD14-induced tumor cell adhesion and invasion. Furthermore, LPS, when combined with sCD14, resulted in NF-kappaB activation in both SW480 and SW620 cells. Inhibition of the NF-kappaB pathway significantly attenuated LPS-induced up-regulation of beta(1) integrin expression and prevented tumor cell adhesion and invasion. These results provide direct evidence that although SW480 and SW620 cells do not express membrane-bound CD14, LPS in the presence of sCD14 can activate NF-kappaB, up-regulate beta(1) integrin expression, and subsequently promote tumor cell adhesion and invasion. Moreover, LPS-induced tumor cell attachment to and invasion through extracellular matrix proteins is beta(1) subunit-dependent.

  16. Induction of cell scattering by expression of beta1 integrins in beta1-deficient epithelial cells requires activation of members of the rho family of GTPases and downregulation of cadherin and catenin function

    Gimond, C; van Der Flier, A; van Delft, S;


    was required for a complete morphological transition towards the spindle-shaped fibroblast-like phenotype. The expression of an interleukin-2 receptor (IL2R)-beta1A chimera and its incorporation into focal adhesions also induced the disruption of cadherin-based adhesions and the reorganization of ECM......Adhesion receptors, which connect cells to each other and to the surrounding extracellular matrix (ECM), play a crucial role in the control of tissue structure and of morphogenesis. In this work, we have studied how intercellular adhesion molecules and beta1 integrins influence each other using two......-catenin protein levels accompanied by their redistribution from the cytoskeleton-associated fraction to the detergent-soluble fraction. Regulation of alpha-catenin protein levels by beta1 integrins is likely to play a role in the morphological transition, since overexpression of alpha-catenin in GE11 cells before...

  17. Highly Potent, Water Soluble Benzimidazole Antagonist for Activated (alpha)4(beta)1 Integrin

    Carpenter, R D; Andrei, M; Lau, E Y; Lightstone, F C; Liu, R; Lam, K S; Kurth, M J


    The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin, activated constitutively in lymphoma, can be targeted with the bisaryl urea peptidomimetic antagonist 1 (LLP2A). However, concerns on its preliminary pharmacokinetic (PK) profile provided an impetus to change the pharmacophore from a bisaryl urea to a 2-arylaminobenzimidazole moiety resulting in improved solubility while maintaining picomolar potency [5 (KLCA4); IC{sub 50} = 305 pM]. With exceptional solubility, this finding has potential for improving PK to help diagnose and treat lymphomas.

  18. Modeled Microgravity Disrupts Collagen I/Integrin Signaling During Osteoblastic Differentiation of Human Mesenchymal Stem Cells

    Meyers, Valerie E.; Zayzafoon, Majd; Gonda, Steven R.; Gathings, William E.; McDonald, Jay M.


    Spaceflight leads to reduced bone mineral density in weight bearing bones that is primarily attributed to a reduction in bone formation. We have previously demonstrated severely reduced osteoblastogenesis of human mesenchymal stem cells (hMSC) following seven days culture in modeled microgravity. One potential mechanism for reduced osteoblastic differentiation is disruption of type I collagen-integrin interactions and reduced integrin signaling. Integrins are heterodimeric transmembrane receptors that bind extracellular matrix proteins and produce signals essential for proper cellular function, survival, and differentiation. Therefore, we investigated the effects of modeled microgravity on integrin expression and function in hMSC. We demonstrate that seven days of culture in modeled microgravity leads to reduced expression of the extracellular matrix protein, type I collagen (Col I). Conversely, modeled microgravity consistently increases Col I-specific alpha2 and beta1 integrin protein expression. Despite this increase in integrin sub-unit expression, autophosphorylation of adhesion-dependent kinases, focal adhesion kinase (FAK) and proline-rich tyrosine kinase 2 (PYK2), is significantly reduced. Activation of Akt is unaffected by the reduction in FAK activation. However, reduced downstream signaling via the Ras-MAPK pathway is evidenced by a reduction in Ras and ERK activation. Taken together, our findings indicate that modeled microgravity decreases integrin/MAPK signaling, which likely contributes to the observed reduction in osteoblastogenesis.

  19. Integrin {alpha}{beta}1, {alpha}{sub v}{beta}, {alpha}{sub 6}{beta} effectors p130Cas, Src and talin regulate carcinoma invasion and chemoresistance

    Sansing, Hope A. [Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center-New Orleans, School of Dentistry, New Orleans, LA (United States); Sarkeshik, Ali; Yates, John R. [Department of Chemical Physiology, Scripps Research Institute, La Jolla, CA (United States); Patel, Vyomesh; Gutkind, J. Silvio [Oral and Pharyngeal Cancer Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States); Yamada, Kenneth M. [Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD (United States); Berrier, Allison L., E-mail: [Department of Oral and Craniofacial Biology, Louisiana State University Health Sciences Center-New Orleans, School of Dentistry, New Orleans, LA (United States)


    Research highlights: {yields} Proteomics of clustered integrin {alpha}{beta}1, {alpha}{sub v}{beta}, {alpha}{sub 6}{beta} receptors in oral carcinoma. {yields} p130Cas, Dek, Src and talin regulate oral carcinoma invasion. {yields} p130Cas, talin, Src and zyxin regulate oral carcinoma resistance to cisplatin. -- Abstract: Ligand engagement by integrins induces receptor clustering and formation of complexes at the integrin cytoplasmic face that controls cell signaling and cytoskeletal dynamics critical for adhesion-dependent processes. This study searches for a subset of integrin effectors that coordinates both tumor cell invasion and resistance to the chemotherapeutic drug cisplatin in oral carcinomas. Candidate integrin effectors were identified in a proteomics screen of proteins recruited to clustered integrin {alpha}{beta}1, {alpha}{sub v}{beta} or {alpha}{sub 6}{beta} receptors in oral carcinomas. Proteins with diverse functions including microtubule and actin binding proteins, and factors involved in trafficking, transcription and translation were identified in oral carcinoma integrin complexes. Knockdown of effectors in the oral carcinoma HN12 cells revealed that p130Cas, Dek, Src and talin were required for invasion through Matrigel. Disruption of talin or p130Cas by RNA interference increased resistance to cisplatin, whereas targeting Dek, Src or zyxin reduced HN12 resistance to cisplatin. Analysis of the spreading of HN12 cells on collagen I and laminin I revealed that a decrease in p130Cas or talin expression inhibited spreading on both matrices. Interestingly, a reduction in zyxin expression enhanced spreading on laminin I and inhibited spreading on collagen I. Reduction of Dek, Src, talin or zyxin expression reduced HN12 proliferation by 30%. Proliferation was not affected by a reduction in p130Cas expression. We conclude that p130Cas, Src and talin function in both oral carcinoma invasion and resistance to cisplatin.

  20. Complementary roles of glycoprotein VI and alpha2beta1 integrin in collagen-induced thrombus formation in flowing whole blood ex vivo

    Kuijpers, Marijke J E; Schulte, Valerie; Bergmeier, Wolfgang; Lindhout, Theo; Brakebusch, Cord; Offermanns, Stefan; Fässler, Reinhard; Heemskerk, Johan W M; Nieswandt, Bernhard


    function in ex vivo thrombus formation during perfusion of whole blood over collagen. With mice deficient in GPVI or blocking antibodies, we found that GPVI was indispensable for collagen-dependent Ca2+ mobilization, exposure of PS, and aggregation of platelets. Deficiency of integrin beta1 reduces the......Platelets interact vigorously with subendothelial collagens that are exposed by injury or pathological damage of a vessel wall. The collagen-bound platelets trap other platelets to form aggregates, and they expose phosphatidylserine (PS) required for coagulation. Both processes are implicated in...... the formation of vaso-occlusive thrombi. We previously demonstrated that the immunoglobulin receptor glycoprotein VI (GPVI), but not integrin alpha2beta1, is essential in priming platelet-collagen interaction and subsequent aggregation. Here, we report that these receptors have yet a complementary...

  1. Metastatic dissemination of human ovarian epithelial carcinoma is promoted by alpha2beta1-integrin-mediated interaction with type I collagen.

    Fishman, D A; Kearns, A; Chilukuri, K; Bafetti, L M; O'Toole, E A; Georgacopoulos, J; Ravosa, M J; Stack, M S


    Metastatic dissemination of epithelial ovarian carcinoma is thought to be mediated via tumor cell exfoliation into the peritoneal cavity, followed by adhesion to and invasion through the mesothelium which overlies the contents of the peritoneal cavity. In this study, we have utilized short-term primary cultures to analyze the effect of specific extracellular matrix proteins on properties of human ovarian epithelial carcinoma cells which contribute to the invasive phenotype. Analysis of cell:matrix adhesive profiles indicated that ovarian carcinoma cells adhere preferentially to type I collagen. Immunoprecipitation analyses demonstrated the presence of the collagen-binding alpha2beta1 integrin in biotin-labeled ovarian carcinoma cell membranes, and cellular adhesion was inhibited by blocking antibodies directed against the alpha2 and beta1 integrin subunits. The alpha2beta1-binding peptide Asp-Gly-Glu-Ala (DGEA) was also moderately effective at blocking adhesion to collagen relative to the control peptide Ala-Gly-Glu-Ala (AGEA). Analysis of cell motility on protein-coated colloidal gold coverslips demonstrated that ovarian carcinoma cells migrate preferentially on type I collagen coated surfaces. Type I collagen promoted migration in a concentration-dependent, saturable manner, with maximal migration observed at a collagen-coating concentration of 50 microg/ml. Migration on collagen was inhibited by antibodies directed against the alpha2 and beta1 integrin subunits and by DGEA peptide, providing evidence for the role of the alpha2beta1 integrin in ovarian carcinoma cell motility. Culturing ovarian carcinoma cells on type I collagen gels led to a significant increase in conversion of the matrix metalloproteinase 2 zymogen to the 66-kD form, suggesting that adhesion to collagen also influences matrix-degrading proteinases. These data suggest that alpha2beta1-integrin-mediated interaction of ovarian carcinoma cells with type I collagen, a protein prevalent both in the

  2. Treatment of marrow stroma with interferon-alpha restores normal beta 1 integrin-dependent adhesion of chronic myelogenous leukemia hematopoietic progenitors. Role of MIP-1 alpha.

    R Bhatia; McGlave, P B; Verfaillie, C M


    The mechanisms by which interferon-alpha (IFN-alpha) restores normal hematopoiesis in chronic myelogenous leukemia (CML) are not well understood. We have recently demonstrated that IFN-alpha acts directly on CML hematopoietic progenitors to restore their adhesion to marrow stroma by modulating beta 1 integrin receptor function. In the present study we examined the effect of IFN-alpha treatment of marrow stroma on subsequent adhesion of CML progenitors. Stromal layers were preincubated with IF...

  3. Integrin {alpha}1{beta}1 promotes caveolin-1 dephosphorylation by activating T cell protein-tyrosine phosphatase.

    Borza, Corina M; Chen, Xiwu; Mathew, Sijo; Mont, Stacey; Sanders, Charles R; Zent, Roy; Pozzi, Ambra


    Integrin α1β1 is a collagen receptor that down-regulates collagen and reactive oxygen species (ROS) production, and mice lacking this receptor show increased ROS levels and exacerbated glomerular sclerosis following injury. Caveolin-1 (Cav-1) is a multifunctional protein that is tyrosine-phosphorylated in response to injury and has been implicated in ROS-mediated injury. Cav-1 interacts with integrins, and integrin α1β1 binds/activates T cell protein-tyrosine phosphatase (TCPTP), which is homologous to the tyrosine phosphatase PTP1B known to dephosphorylate Cav-1. In this study, we analyzed whether phosphorylated Cav-1 (pCav-1) is a substrate of TCPTP and if integrin α1β1 is essential for promoting TCPTP-mediated Cav-1 dephosphorylation. We found that Cav-1 phosphorylation is significantly higher in cells lacking integrin α1β1 at base line and following oxidative stress. Overexpression of TCPTP leads to reduced pCav-1 levels only in cells expressing integrin α1β1. Using solid phase binding assays, we demonstrated that 1) purified Cav-1 directly interacts with TCPTP and the integrin α1 subunit, 2) pCav-1 is a substrate of TCPTP, and 3) TCPTP-mediated Cav-1 dephosphorylation is highly increased by the addition of purified integrin α1β1 or an integrin α1 cytoplasmic peptide to which TCPTP has been shown to bind. Thus, our results demonstrate that pCav-1 is a new substrate of TCPTP and that integrin α1β1 acts as a negative regulator of Cav-1 phosphorylation by activating TCPTP. This could explain the protective function of integrin α1β1 in oxidative stress-mediated damage and why integrin α1-null mice are more susceptible to fibrosis following injury. PMID:20940300

  4. The alpha3 laminin subunit, alpha6beta4 and alpha3beta1 integrin coordinately regulate wound healing in cultured epithelial cells and in the skin

    Goldfinger, L E; Hopkinson, S B; deHart, G W;


    function-inhibiting antibodies, we provide evidence that LN5 and its two integrin receptors (alpha6beta4 and alpha3beta1) appear necessary for wound healing to occur in MCF-10A cell culture wounds. We propose a model for healing of wounded epithelial tissues based on these results....... epithelial cells. We have prepared a monoclonal antibody (12C4) whose epitope is located toward the carboxy terminus of the globular domain of the alpha3 laminin subunit. This epitope is lost from the alpha3 subunit as a consequence of proteolytic processing. Antibody 12C4 stains throughout the matrix of...... cover the wound site. A similar phenomenon is observed in human skin wounds, since we also detect expression of the unprocessed alpha3 laminin subunit at the leading tip of the sheet of epidermal cells that epithelializes skin wounds in vivo. In addition, using alpha3 laminin subunit and integrin...

  5. Molecular cloning and phylogenetic analysis of integrins alpha v beta 1 and alpha v beta 6 of one-humped camel (Camelus dromedarius)

    Du, Junzheng; Larska, Magdalena Larska; Chang, Huiyun;


    Bactrian camels can relatively easily be infected with FMDV, but dromedary camels remain resistant even to high doses of the virus. To understand the different susceptibility between the two camel species from the standpoint of viral receptors, this work reports the sequences of the dromedary camel...... into the Artiodactyla group, together with those of Bactrian camel, pig, sheep, and cattle that are susceptible to FMDV infection. Compared with the Bactrian camel integrins, 4, 10, and 8 amino acid changes were found in the dromedary camel alpha v, beta 1, and beta 6 subunits, respectively. This study...... will be of importance in understanding the differences of integrins as FMDV receptors among dromedary camel and other species. Crown...

  6. Dystrophin Dp71f associates with the beta1-integrin adhesion complex to modulate PC12 cell adhesion

    Cerna, Joel; Cerecedo, Doris; Ortega, Arturo; García-Sierra, Francisco; Centeno, Federico; Garrido, Efrain; Mornet, Dominique; Cisneros, Bulmaro


    Dystrophin Dp71 is the main product of the Duchenne muscular dystrophy gene in the brain; however, its function is unknown. To study the role of Dp71 in neuronal cells, we previously generated by antisense treatment PC12 neuronal cell clones with decreased Dp71 expression (antisense-Dp71 cells). PC12 cells express two different splicing isoforms of Dp71, a cytoplasmic variant called Dp71f and a nuclear isoform called Dp71d. We previously reported that antisense-Dp71 cells display deficient adhesion to substrate and reduced immunostaining of β1-integrin in the cell area contacting the substrate. In this study, we isolated additional antisenseDp71 clones to analyze in detail the potential involvement of Dp71f isoform with the β1-integrin adhesion system of PC12 cells. Immunofluorescence analyses as well as immunoprecipitation assays demonstrated that the PC12 cell β1-integrin adhesion complex is composed of β1-integrin, talin, paxillin, α-actinin, FAK and actin. In addition, our results showed that Dp71f associates with most of the β1-integrin complex components (β1-integrin, FAK, α-actinin, talin and actin). In the antisense-Dp71 cells, the deficiency of Dp71 provokes a significant reduction of the β1-integrin adhesion complex and, consequently, the deficient adhesion of these cells to laminin. In vitro binding experiments confirmed the interaction of Dp71f with FAK and β1-integrin. Our data indicate that Dp71f is a structural component of the β1-integrin adhesion complex of PC12 cells that modulates PC12 cell adhesion by conferring proper complex assembly and/or maintenance. PMID:16935300

  7. Production of IL1-beta by ovarian cancer cells induces mesothelial cell beta1-integrin expression facilitating peritoneal dissemination

    Watanabe Takafumi


    Full Text Available Abstract Background A crucial step in the metastatic spread of ovarian cancer (OC is the adhesion and implantation of tumor cells to the peritoneal mesothelium. In order to study this step in the cascade, we derived a pro-metastatic human ovarian carcinoma cell line (MFOC3 from the non-metastatic FOC3 line. Methods Molecular profiling of the isogeneic lines identified differentially expressed genes, and investigation for a role in dissemination for specific factors was achieved by development of a co-culture adhesion assay utilizing monolayers of human mesothelial cells. Results After murine intraperitoneal inoculation, the FOC3 cell line formed no metastases, but the MFOC3 subline formed metastases in > 80% of SCID mice. MFOC3 cells also adhered 2-3 times more avidly to mesothelial monolayers. This adhesion was inhibited by neutralizing antibodies to IL-1β and enhanced by recombinant IL-1β (p in vitro and significantly reduced metastases in vivo. Immunohistochemical analysis of a cohort of 96 ovarian cancer cases showed that negative IL-1β expression was significantly associated with an improved overall survival rate. Conclusions These results suggest that a IL-1β/β1-integrin axis plays a role in ovarian tumor cell adhesion to mesothelia, a crucial step in ovarian cancer dissemination.

  8. Distinct roles of beta1 metal ion-dependent adhesion site (MIDAS), adjacent to MIDAS (ADMIDAS), and ligand-associated metal-binding site (LIMBS) cation-binding sites in ligand recognition by integrin alpha2beta1.

    Valdramidou, Dimitra; Humphries, Martin J; Mould, A Paul


    Integrin-ligand interactions are regulated in a complex manner by divalent cations, and previous studies have identified ligand-competent, stimulatory, and inhibitory cation-binding sites. In collagen-binding integrins, such as alpha2beta1, ligand recognition takes place exclusively at the alpha subunit I domain. However, activation of the alphaI domain depends on its interaction with a structurally similar domain in the beta subunit known as the I-like or betaI domain. The top face of the betaI domain contains three cation-binding sites: the metal-ion dependent adhesion site (MIDAS), the ADMIDAS (adjacent to MIDAS), and LIMBS (ligand-associated metal-binding site). The role of these sites in controlling ligand binding to the alphaI domain has yet to be elucidated. Mutation of the MIDAS or LIMBS completely blocked collagen binding to alpha2beta1; in contrast mutation of the ADMIDAS reduced ligand recognition but this effect could be overcome by the activating monoclonal antibody TS2/16. Hence, the MIDAS and LIMBS appear to be essential for the interaction between alphaI and betaI, whereas occupancy of the ADMIDAS has an allosteric effect on the conformation of betaI. An activating mutation in the alpha2 I domain partially restored ligand binding to the MIDAS and LIMBS mutants. Analysis of the effects of Ca(2+), Mg(2+), and Mn(2+) on ligand binding to these mutants showed that the MIDAS is a ligand-competent site through which Mn(2+) stimulates ligand binding, whereas the LIMBS is a stimulatory Ca(2+)-binding site, occupancy of which increases the affinity of Mg(2+) for the MIDAS. PMID:18820259

  9. The signaling pathway of Campylobacter jejuni-induced Cdc42 activation: Role of fibronectin, integrin beta1, tyrosine kinases and guanine exchange factor Vav2

    Krause-Gruszczynska, Malgorzata


    Abstract Background Host cell invasion by the foodborne pathogen Campylobacter jejuni is considered as one of the primary reasons of gut tissue damage, however, mechanisms and key factors involved in this process are widely unclear. It was reported that small Rho GTPases, including Cdc42, are activated and play a role during invasion, but the involved signaling cascades remained unknown. Here we utilised knockout cell lines derived from fibronectin-\\/-, integrin-beta1-\\/-, focal adhesion kinase (FAK)-\\/- and Src\\/Yes\\/Fyn-\\/- deficient mice, and wild-type control cells, to investigate C. jejuni-induced mechanisms leading to Cdc42 activation and bacterial uptake. Results Using high-resolution scanning electron microscopy, GTPase pulldowns, G-Lisa and gentamicin protection assays we found that each studied host factor is necessary for induction of Cdc42-GTP and efficient invasion. Interestingly, filopodia formation and associated membrane dynamics linked to invasion were only seen during infection of wild-type but not in knockout cells. Infection of cells stably expressing integrin-beta1 variants with well-known defects in fibronectin fibril formation or FAK signaling also exhibited severe deficiencies in Cdc42 activation and bacterial invasion. We further demonstrated that infection of wild-type cells induces increasing amounts of phosphorylated FAK and growth factor receptors (EGFR and PDGFR) during the course of infection, correlating with accumulating Cdc42-GTP levels and C. jejuni invasion over time. In studies using pharmacological inhibitors, silencing RNA (siRNA) and dominant-negative expression constructs, EGFR, PDGFR and PI3-kinase appeared to represent other crucial components upstream of Cdc42 and invasion. siRNA and the use of Vav1\\/2-\\/- knockout cells further showed that the guanine exchange factor Vav2 is required for Cdc42 activation and maximal bacterial invasion. Overexpression of certain mutant constructs indicated that Vav2 is a linker

  10. Human macrophage differentiation involves an interaction between integrins and fibronectin

    Laouar, A.; Chubb, C.B.H.; Collart, F.; Huberman, E.


    The authors have examined the role of integrins and extracellular matrix (ECM) proteins in macrophage differentiation of (1) human HL-60 myeloid leukemia cells induced by phorbol 12-myristate 13-acetate (PMA) and (2) human peripheral blood monocytes induced by either PMA or macrophage-colony stimulating factor (M-CSF). Increased {beta}{sub 1} integrin and fibronectin (FN) gene expression was observed in PMA-treated HL-60 cells and PMA- or M-CSF-treated monocytes, even at a time preceding the manifestation of macrophage markers. Treated HL-60 cells and monocytes also released and deposited FN on the culture dishes. An HL-60 cell variant, HL-525, which is deficient in protein kinase C {beta} (PKC{beta}) and resistant to PMA-induced differentiation, failed to express FN after PMA treatment. Restoration of PKC{beta} resulted in PMA-induced FN gene expression and macrophage differentiation. The macrophage phenotype induced in HL-60 cells or monocytes was attenuated by anti-{beta}{sub 1} integrin or anti-FN MAbs. The authors suggest that macrophage differentiation involves activation of PKC and expression of specific integrins and ECM proteins. The stimulated cells, through their integrins, attach and spread on these substrates by binding to the deposited ECM proteins. This attachment and spreading in turn, through integrin signaling, leads to the macrophage phenotype.

  11. Function of the integrin alpha 6 beta 1 in metastatic breast carcinoma cells assessed by expression of a dominant-negative receptor

    Shaw, L M; Chao, C; Wewer, U M;


    : alpha 2 beta 1, alpha 3 beta 1, and alpha 6 beta 1, but uses only alpha 6 beta 1 to mediate adhesion and migration on laminin matrices. To investigate the contribution of alpha 6 beta 1 to the aggressive behavior of these cells, we developed a dominant-negative strategy for knocking out alpha 6 beta 1...

  12. Venom gland EST analysis of the saw-scaled viper, Echis ocellatus, reveals novel alpha9beta1 integrin-binding motifs in venom metalloproteinases and a new group of putative toxins, renin-like aspartic proteases.

    Wagstaff, Simon C; Harrison, Robert A


    Echis ocellatus is the most medically important snake in West Africa. However, the composition of its venom and the differential contribution of these venom components to the severe haemorrhagic and coagulopathic pathology of envenoming are poorly understood. To address this situation we assembled a toxin transcriptome based upon 1000 expressed sequence tags (EST) from a cDNA library constructed from pooled venom glands of 10 individual E. ocellatus. We used a variety of bioinformatic tools to construct a fully annotated venom-toxin transcriptome that was interrogated with a combination of BLAST annotation, gene ontology cataloguing and disintegrin-motif searching. The results of these analyses revealed an unusually abundant and diverse expression of snake venom metalloproteinases (SVMP) and a broad toxin-expression profile including several distinct isoforms of bradykinin-potentiating peptides, phospholipase A(2), C-type lectins, serine proteinases and l-amino oxidases. Most significantly, we identified for the first time a conserved alpha(9)beta(1) integrin-binding motif in several SVMPs, and a new group of putative venom toxins, renin-like aspartic proteases. PMID:16713134

  13. Integrin beta 1 enhances the epithelial-mesenchymal transition in association with gefitinib resistance of non-small cell lung cancer.

    Ju, Lixia; Zhou, Caicun


    We have previously shown that integrinβ1 associates with gefitinib resistance. As epithelial-mesenchymal transition (EMT) also induces gefitinib resistance in vitro, we wished to determine the relation of them in gefitinib resistance. In this study, we show that integrinβ1 induced epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) resistance in xenograft tumors and gefitinib-resistant NSCLC tumors acquired EMT phenotype. Furthermore, inhibition of integrinβ1 reverses EMT, meanwhile overexpression and activation of integrinβ1 aggravates EMT. Lastly, we further identified that integrinβ1 enhanced EMT via FAK-AKT signaling pathway. These findings highlight a novel relation of integrinβ1 and EMT in EGFR TKI resistant NSCLC. PMID:24440972

  14. Investigating the role of Integrin Linked Kinase in mammary epithelial cell differentiation

    Rooney, Nicholas


    Epithelial cell adhesion to the surrounding extracellular matrix (ECM) is necessary for their proper behaviour and function. During pregnancy and lactation mammary epithelial cells (MECs) require signals imparted by specific β1 integrin-laminin interactions for their functional differentiation in response to Prolactin (Prl) and for the correct formation of polarised secretory acini. Downstream of β1 integrin (β1Itg), the scaffold protein Integrin Linked Kinase (ILK) has been identified as the...

  15. Integrin alpha 5 beta 1 Plays a Critical Role in Resistance to Temozolomide by Interfering with the p53 Pathway in High-Grade Glioma

    Janoušková, Hana; Maglott, A.; Leger, D.Y.; Bossert, C.; Noulet, F.; Guerin, E.; Guenot, D.; Pinel, S.; Chastagner, P.; Plenat, F.; Entz-Werle, N.; Lehmann-Che, J.; Godet, J.; Martin, S.; Teisinger, Jan; Dontenwill, M.


    Roč. 72, č. 14 (2012), s. 3463-3470. ISSN 0008-5472 Institutional support: RVO:67985823 Keywords : cancer * integrins * high-grade glioma Subject RIV: CE - Biochemistry Impact factor: 8.650, year: 2012

  16. Measurement of the Interaction Between Recombinant I-domain from Integrin alpha 2 beta 1 and a Triple Helical Collagen Peptide with the GFOGER Binding Motif Using Molecular Force Spectroscopy

    Mark E. Welland


    Full Text Available The role of the collagen-platelet interaction is of crucial importance to the haemostatic response during both injury and pathogenesis of the blood vessel wall. Of particular interest is the high affinity interaction of the platelet transmembrane receptor, alpha 2 beta 1, responsible for firm attachment of platelets to collagen at and around injury sites. We employ single molecule force spectroscopy (SMFS using the atomic force microscope (AFM to study the interaction of the I-domain from integrin alpha 2 beta 1 with a synthetic collagen related triple-helical peptide containing the high-affinity integrin-binding GFOGER motif, and a control peptide lacking this sequence, referred to as GPP. By utilising synthetic peptides in this manner we are able to study at the molecular level subtleties that would otherwise be lost when considering cell-to-collagen matrix interactions using ensemble techniques. We demonstrate for the first time the complexity of this interaction as illustrated by the complex multi-peaked force spectra and confirm specificity using control blocking experiments. In addition we observe specific interaction of the GPP peptide sequence with the I-domain. We propose a model to explain these observations.

  17. Discovery, SAR, and Radiolabeling of Halogenated Benzimidazole Carboxamide Antagonists as Useful Tools for (alpha)4(beta)1 Integrin Expressed on T- and B-cell Lymphomas

    Carpenter, R D; Natarajan, A; Lau, E Y; Andrei, M; Solano, D M; Lightstone, F C; DeNardo, S J; Lam, K S; Kurth, M J


    The cell surface receptor {alpha}{sub 4}{beta}{sub 1} integrin is an attractive yet poorly understood target for selective diagnosis and treatment of T- and B-cell lymphomas. This report focuses on the rapid microwave preparation of medicinally pertinent benzimidazole heterocycles, structure-activity relationships (SAR) of novel halobenzimidazole carboxamide antagonists 3-6, and preliminary biological evaluation of radioiodinated agents 7, 8, and 18. The I-125 derivative 18 had good tumor uptake (12 {+-} 1% ID/g at 24 h; 4.5 {+-} 1% ID/g at 48 h) and tumor:kidney ratio ({approx}4:1 at 24 h; 2.5:1 at 48 h) in xenograft murine models of B-cell lymphoma. Molecular homology models of {alpha}{sub 4}{beta}{sub 1} integrin have predicted that docked halobenzimidazole carboxamides have the halogen atom in a suitable orientation for halogen-hydrogen bonding. These high affinity ({approx} pM binding) halogenated ligands are attractive tools for medicinal and biological use; the fluoro and iodo derivatives are potential radiodiagnostic ({sup 18}F) or radiotherapeutic ({sup 131}I) agents, whereas the chloro and bromo analogues could provide structural insight into integrin-ligand interactions through photoaffinity cross-linking/mass spectroscopy experiments, as well as co-crystallization X-ray studies.

  18. Signaling from beta1- and beta2-adrenergic receptors is defined by differential interactions with PDE4

    Richter, Wito; Day, Peter; Agrawal, Rani; Bruss, Matthew D; Granier, Sébastien; Wang, Yvonne L; Rasmussen, Søren Gøgsig Faarup; Horner, Kathleen; Wang, Ping; Lei, Tao; Patterson, Andrew J; Kobilka, Brian; Conti, Marco


    Beta1- and beta2-adrenergic receptors (betaARs) are highly homologous, yet they play clearly distinct roles in cardiac physiology and pathology. Myocyte contraction, for instance, is readily stimulated by beta1AR but not beta2AR signaling, and chronic stimulation of the two receptors has opposing...

  19. Osteogenic differentiation of mesenchymal stem cells from dental bud: Role of integrins and cadherins

    Adriana Di Benedetto


    Full Text Available Several studies have reported the beneficial effects of mesenchymal stem cells (MSCs in tissue repair and regeneration. New sources of stem cells in adult organisms are continuously emerging; dental tissues have been identified as a source of postnatal MSCs. Dental bud is the immature precursor of the tooth, is easy to access and we show in this study that it can yield a high number of cells with ≥95% expression of mesenchymal stemness makers and osteogenic capacity. Thus, these cells can be defined as Dental Bud Stem Cells (DBSCs representing a promising source for bone regeneration of stomatognathic as well as other systems. Cell interactions with the extracellular matrix (ECM and neighboring cells are critical for tissue morphogenesis and architecture; such interactions are mediated by integrins and cadherins respectively. We characterized DBSCs for the expression of these adhesion receptors and examined their pattern during osteogenic differentiation. Our data indicate that N-cadherin and cadherin-11 were expressed in undifferentiated DBSCs and their expression underwent changes during the osteogenic process (decreasing and increasing respectively, while expression of E-cadherin and P-cadherin was very low in DBSCs and did not change during the differentiation steps. Such expression pattern reflected the mesenchymal origin of DBSCs and confirmed their osteoblast-like features. On the other hand, osteogenic stimulation induced the upregulation of single subunits, αV, β3, α5, and the formation of integrin receptors α5β1 and αVβ3. DBSCs differentiation toward osteoblastic lineage was enhanced when cells were grown on fibronectin (FN, vitronectin (VTN, and osteopontin (OPN, ECM glycoproteins which contain an integrin-binding sequence, the RGD motif. In addition we established that integrin αVβ3 plays a crucial role during the commitment of MSCs to osteoblast lineage, whereas integrin α5β1 seems to be dispensable. These data suggest

  20. Hierarchy of ADAM12 binding to integrins in tumor cells

    Thodeti, Charles Kumar; Fröhlich, Camilla; Nielsen, Christian Kamp;


    12. However, when alpha9beta1 integrin is not expressed--as in many carcinoma cells--other members of the beta1 integrin family can replace its ligand binding activity. In attachment assays, the recombinant disintegrin domain of ADAM12 only supported alpha9 integrin-dependent tumor cell attachment...... with a rounded morphology; attachment of cells with a spread morphology required further activation of the alpha9beta1 integrin. We demonstrated that phosphoinositide-3-kinase appears to be central in regulating alpha9beta1 integrin cell spreading activity in response to ADAM12....

  1. Evaluation of β1-integrin expression on chondrogenically differentiating human adipose-derived stem cells using atomic force microscopy.

    Quisenberry, Chrystal R; Nazempour, Arshan; Van Wie, Bernard J; Abu-Lail, Nehal I


    The expression of β1-integrin on human adipose-derived stem cells, differentiating toward a chondrogenic lineage, is hypothesized to decrease when cells are grown under in vivo-like environments due to sufficient extracellular matrix (ECM) buildup in the engineered tissues. The opposite is true when cells are grown in static cultures such as in pellet or micromass. To probe β1-integrin distribution on cellular surfaces, atomic force microscopy cantilevers modified with anti-β1-integrin antibodies were used. Specific antibody-antigen adhesion forces were identified and indicated the locations of β1-integrins on cells. ECM properties were assessed by estimating the Young's modulus of the matrix. Specific single antibody-antigen interactions averaged 78 ± 10 pN with multiple bindings occurring at approximate multiples of 78 pN. The author's results show that upregulated β1-integrin expression coincided with a less robust ECM as assessed by mechanical properties of tissues. In micromass and pellet cultures, transforming growth factor β3(TGF-β3) elicited a decrease in Young's modulus by 3.7- and 4.4-fold while eliciting an increase in β1-integrin count by 1.1- and 1.3-fold, respectively. β1-integrin counts on cells grown in the presence of TGF-β3 with oscillating hydrostatic pressure decreased by a 1.1-fold while the Young's modulus increased by a 1.9-fold. Collectively, our results suggest that cells in insufficiently robust ECM express more integrin perhaps to facilitate cell-ECM adhesion and compensate for a looser less robust ECM. PMID:27106564

  2. α2 Integrin, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-3 act sequentially to induce differentiation of mouse embryonic stem cells into odontoblast-like cells

    Ozeki, Nobuaki; Kawai, Rie; Hase, Naoko; Hiyama, Taiki; Yamaguchi, Hideyuki [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Kondo, Ayami [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan); Nakata, Kazuhiko [Department of Endodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Aichi 464-8651 (Japan); Mogi, Makio, E-mail: [Department of Medicinal Biochemistry, School of Pharmacy, Aichi Gakuin University, Nagoya 464-8650 (Japan)


    We previously reported that interleukin 1β acts via matrix metalloproteinase (MMP)-3 to regulate cell proliferation and suppress apoptosis in α2 integrin-positive odontoblast-like cells differentiated from mouse embryonic stem (ES) cells. Here we characterize the signal cascade underpinning odontoblastic differentiation in mouse ES cells. The expression of α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and MMP-3 mRNA and protein were all potently increased during odontoblastic differentiation. Small interfering RNA (siRNA) disruption of the expression of these effectors potently suppressed the expression of the odontoblastic biomarkers dentin sialophosphoprotein, dentin matrix protein-1 and alkaline phosphatase, and blocked odontoblast calcification. Our siRNA, western blot and blocking antibody analyses revealed a unique sequential cascade involving α2 integrin, Emmprin and MMP-3 that drives ES cell differentiation into odontoblasts. This cascade requires the interaction between α2 integrin and Emmprin and is potentiated by exogenous MMP-3. Finally, although odontoblast-like cells potently express α2, α6, αV, β1, and β3, integrins, we confirmed that β1 integrin acts as the trigger for ES cell differentiation, apparently in complex with α2 integrin. These results demonstrate a unique and unanticipated role for an α2 integrin-, Emmprin-, and MMP-3-mediated signaling cascade in driving mouse ES cell differentiation into odontoblast-like cells. - Highlights: • Odontoblast differentiation requires activation of α2 integrin, Emmprin and MMP-3. • α2 integrin, Emmprin and MMP-3 form a sequential signaling cascade. • β1 integrin acts a specific trigger for odontoblast differentiation. • The role of these effectors is highly novel and unanticipated.

  3. α2 Integrin, extracellular matrix metalloproteinase inducer, and matrix metalloproteinase-3 act sequentially to induce differentiation of mouse embryonic stem cells into odontoblast-like cells

    We previously reported that interleukin 1β acts via matrix metalloproteinase (MMP)-3 to regulate cell proliferation and suppress apoptosis in α2 integrin-positive odontoblast-like cells differentiated from mouse embryonic stem (ES) cells. Here we characterize the signal cascade underpinning odontoblastic differentiation in mouse ES cells. The expression of α2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and MMP-3 mRNA and protein were all potently increased during odontoblastic differentiation. Small interfering RNA (siRNA) disruption of the expression of these effectors potently suppressed the expression of the odontoblastic biomarkers dentin sialophosphoprotein, dentin matrix protein-1 and alkaline phosphatase, and blocked odontoblast calcification. Our siRNA, western blot and blocking antibody analyses revealed a unique sequential cascade involving α2 integrin, Emmprin and MMP-3 that drives ES cell differentiation into odontoblasts. This cascade requires the interaction between α2 integrin and Emmprin and is potentiated by exogenous MMP-3. Finally, although odontoblast-like cells potently express α2, α6, αV, β1, and β3, integrins, we confirmed that β1 integrin acts as the trigger for ES cell differentiation, apparently in complex with α2 integrin. These results demonstrate a unique and unanticipated role for an α2 integrin-, Emmprin-, and MMP-3-mediated signaling cascade in driving mouse ES cell differentiation into odontoblast-like cells. - Highlights: • Odontoblast differentiation requires activation of α2 integrin, Emmprin and MMP-3. • α2 integrin, Emmprin and MMP-3 form a sequential signaling cascade. • β1 integrin acts a specific trigger for odontoblast differentiation. • The role of these effectors is highly novel and unanticipated

  4. Quantitative Phosphoproteomic Study Reveals that Protein Kinase A Regulates Neural Stem Cell Differentiation Through Phosphorylation of Catenin Beta-1 and Glycogen Synthase Kinase 3β.

    Wang, Shuxin; Li, Zheyi; Shen, Hongyan; Zhang, Zhong; Yin, Yuxin; Wang, Qingsong; Zhao, Xuyang; Ji, Jianguo


    Protein phosphorylation is central to the understanding of multiple cellular signaling pathways responsible for regulating the self-renewal and differentiation of neural stem cells (NSCs). Here we performed a large-scale phosphoproteomic analysis of rat fetal NSCs using strong cation exchange chromatography prefractionation and citric acid-assisted two-step enrichment with TiO2 strategy followed by nanoLC-MS/MS analysis. Totally we identified 32,546 phosphosites on 5,091 phosphoproteins, among which 23,945 were class I phosphosites, and quantified 16,000 sites during NSC differentiation. More than 65% of class I phosphosites were novel when compared with PhosphoSitePlus database. Quantification results showed that the early and late stage of NSC differentiation differ greatly. We mapped 69 changed phosphosites on 20 proteins involved in Wnt signaling pathway, including S552 on catenin beta-1 (Ctnnb1) and S9 on glycogen synthase kinase 3β (Gsk3β). Western blotting and real-time PCR results proved that Wnt signaling pathway plays critical roles in NSC fate determination. Furthermore, inhibition and activation of PKA dramatically affected the phosphorylation state of Ctnnb1 and Gsk3β, which regulates the differentiation of NSCs. Our data provides a valuable resource for studying the self-renewal and differentiation of NSCs. Stem Cells 2016;34:2090-2101. PMID:27097102

  5. Differential effects of bone morphogenetic protein-2 and transforming growth factor-beta1 on gene expression of collagen-modifying enzymes in human adipose tissue-derived mesenchymal stem cells.

    Knippenberg, Marlene; Helder, Marco N; Doulabi, Behrouz Zandieh; Bank, Ruud A; Wuisman, Paul I J M; Klein-Nulend, Jenneke


    Adipose tissue-derived mesenchymal stem cells (AT-MSCs) in combination with bone morphogenetic protein-2 (BMP-2) or transforming growth factor-beta1 (TGF-beta1) are under evaluation for bone tissue engineering. Posttranslational modification of type I collagen is essential for functional bone tissue with adequate physical and mechanical properties. We investigated whether BMP-2 (10-100 ng/mL) and/or TGF-beta1 (1-10 ng/mL) affect gene expression of alpha2(I) procollagen and collagen-modifying enzymes, that is, lysyl oxidase and lysyl hydroxylases 1, 2, and 3 (encoded by PLOD1, 2, and 3), by human AT-MSCs. BMP-2, but not TGF-beta1, increased alkaline phosphatase activity after 28 days, indicating osteogenic differentiation of AT-MSCs. At day 4, both BMP-2 and TGF-beta1 upregulated alpha2(I) procollagen and PLOD1, which was downregulated at day 28. TGF-beta1, but not BMP-2, downregulated PLOD3 at day 28. Lysyl oxidase was upregulated by TGF-beta1 at day 4 and by BMP-2 at day 7. Neither BMP-2 nor TGF-beta1 affected PLOD2. In conclusion, these results suggest that AT-MSCs differentially respond to BMP-2 and TGF-beta1 with changes in gene expression of collagen-modifying enzymes. AT-MSCs may thus be able to appropriately modify type I collagen to form a functional bone extracellular matrix for tissue engineering, dependent on the growth factor added. PMID:19231972

  6. β3-integrin is required for differentiation in OC-2 cells derived from mammalian embryonic inner ear

    Brunetta Ivan


    Full Text Available Abstract Background The mammalian inner ear contains the organ of Corti which is responsible for the conversion of sound into neuronal signals. This specialised epithelial tissue is the product of a complex developmental process where a common precursor cell type differentiates into the sound transducing hair cells and the non-innervated supporting cells. We hypothesised that integrin proteins, which are involved in cell attachment to extracellular matrix proteins and cellular signalling, play a role in the differentiation process of the precursor inner ear epithelial cells. To test our hypothesis we have utilised a cell line (OC-2 derived from E13 embryonic immortomouse inner ears. In vitro, by switching the incubation temperature from 33°C to 39°C, the OC-2 cells can be induced to differentiate and express hair cells markers, such as Myosin VIIa. The OC-2 cells are thus a useful model system for testing mechanism of hair cells differentiation. Results We have identified 4 integrin subunits which are expressed in OC-2 cells: α6, αv, β1 and β3. Among these, the relative level of expression of the αv, β1 and β3 subunits increased in a time dependent manner when the cells were exposed to the differentiating temperature of 39°C, most notably so for β3 which was not detectable at 33°C. Treatment of fully differentiated OC-2 cells with siRNA against the four integrin subunits reduced the expression of not only the respective integrin proteins but also of the hair cell marker Myosin VIIa. Conversely over-expression of β3 was sufficient to induce the expression of Myosin VIIa at 33°C. Conclusions Our data demonstrate that modulation of integrin expression is associated with the differentiation process of the OC-2 cells. This suggests that the maturation of the organ of Corti, from where OC-2 cells are derived, may also depend on changes of gene expression associated with integrin expression.

  7. Measurement of the Interaction Between Recombinant I-domain from Integrin alpha 2 beta 1 and a Triple Helical Collagen Peptide with the GFOGER Binding Motif Using Molecular Force Spectroscopy

    Welland, Mark E.; Farndale, Richard W.; Dominique Bihan; Debdulal Roy; Simon J Attwood; Simpson, Anna M. C.; Hamaia, Samir W.


    The role of the collagen-platelet interaction is of crucial importance to the haemostatic response during both injury and pathogenesis of the blood vessel wall. Of particular interest is the high affinity interaction of the platelet transmembrane receptor, alpha 2 beta 1, responsible for firm attachment of platelets to collagen at and around injury sites. We employ single molecule force spectroscopy (SMFS) using the atomic force microscope (AFM) to study the interaction of the I-domain from i...

  8. Natalizumab plus interferon beta-1a for relapsing multiple sclerosis.

    Rudick, R.A.; Stuart, W.H.; Calabresi, P.A.; Confavreux, C.; Galetta, S.L.; Radue, E.W.; Lublin, F.D.; Weinstock-Guttman, B.; Wynn, D.R.; Lynn, F.; Panzara, M.A.; Sandrock, A.W.


    BACKGROUND: Interferon beta is used to modify the course of relapsing multiple sclerosis. Despite interferon beta therapy, many patients have relapses. Natalizumab, an alpha4 integrin antagonist, appeared to be safe and effective alone and when added to interferon beta-1a in preliminary studies. MET

  9. The Integrin-Mediated ILK-Parvin-αPix Signaling Axis Controls Differentiation in Mammary Epithelial Cells.

    Rooney, Nicholas; Wang, Pengbo; Brennan, Keith; Gilmore, Andrew P; Streuli, Charles H


    Epithelial cell adhesion to the surrounding extracellular matrix is necessary for their proper behavior and function. During pregnancy and lactation, mammary epithelial cells (MECs) receive signals from their interaction with laminin via β1-integrin (β1-itg) to establish apico-basal polarity and to differentiate in response to prolactin. Downstream of β1-itg, the scaffold protein Integrin Linked Kinase (ILK) has been identified as the key signal transducer that is required for both lactational differentiation and the establishment of apico-basal polarity. ILK is an adaptor protein that forms the IPP complex with PINCH and Parvins, which are central to its adaptor functions. However, it is not known how ILK and its interacting partners control tissue-specific gene expression. Expression of ILK mutants, which weaken the interaction between ILK and Parvin, revealed that Parvins have a role in mammary epithelial differentiation. This conclusion was supported by shRNA-mediated knockdown of the Parvins. In addition, shRNA knockdown of the Parvin-binding guanine nucleotide exchange factor αPix prevented prolactin-induced differentiation. αPix depletion did not disrupt focal adhesions, MEC proliferation, or polarity. This suggests that αPix represents a differentiation-specific bifurcation point in β1-itg-ILK adhesive signaling. In summary, this study has identified a new role for Parvin and αPix downstream of the integrin-ILK signaling axis for MEC differentiation. J. Cell. Physiol. 231: 2408-2417, 2016. © 2016 Wiley Periodicals, Inc. PMID:27019299

  10. Why cellular stress suppresses adipogenesis in skeletal tissue, but is ineffective in adipose tissue: Control of mesenchymal cell differentiation via integrin binding sites in extracellular matrices

    Volloch, Vladimir; Olsen, Bjorn R.


    This Perspective addresses one of the major puzzles of adipogenesis in adipose tissue, namely its resistance to cellular stress. It introduces a concept of “density” of integrin binding sites in extracellular matrix, proposes a cellular signaling explanation for the observed effects of matrix elasticity and of cell shape on mesenchymal stem cell differentiation, and discusses how specialized integrin binding sites in collagen IV - containing matrices guard two pivotal physiological and evolut...

  11. Biomimetic integrin-specific surfaces to direct osteoblastic function and tissue healing

    Petrie, Timothy Andrew

    Current orthopedic implant technologies used suffer from slow rates of osseointegration, short lifetime, and lack of mechanical integrity as a result of poorly controlled cell-surface interactions. Recent biologically-inspired surface strategies (biomimetic) have focused on mimicking the biofunctionality of the extracellular matrix (ECM) by using short, adhesive oligopeptides, such as arginine-glycine-aspartic acid (RGD) present in numerous ECM components. However, these strategies have yielded mixed results in vivo and marginal bone healing responses. The central goal of this dissertation project was to engineer bioactive surfaces that specifically target integrin receptors important for osteogenic functions in order to improve bone tissue repair. In order to create integrin-specific interfaces, integrin-specific ligands reconstituting the fibronectin (FN) secondary/tertiary structure were first engineered and functionalized on material surfaces using several robust presentation schemes. We demonstrated that FN-mimetic-functionalized surfaces that directed alpha 5beta1 binding enhanced osteoblast and stromal cell integrin binding and adhesion, osteogenic signaling, and osteoblastic differentiation compared to various other RGD-based ligand-functionalized surfaces. Next, we investigated the effect of integrin-specific biointerfaces to modulate bone healing in a rat tibia implant bone model. We demonstrated, using a robust polymer brush system, that bioactive coatings on titanium implants that conferred high alpha5beta1 integrin specificity in vitro enhanced bone formation and implant integration in vivo. Moreover, we showed that integrin specificity can be engineered using different immobilization schemes, including clinically-relevant ligand dip-coating, and promote the same robust in vivo effect. Furthermore, we investigate the synergistic roles of integrin specificity and ligand clustering on cell response by engineering biointerfaces presenting trimeric and

  12. Low-Shear Modelled Microgravity Environment Maintains Morphology and Differentiated Functionality of Primary Porcine Hepatocyte Cultures

    Nelson, Leonard J; Walker, Simon W.; Peter C. Hayes; Plevris, John N


    Hepatocytes cultured in conventional static culture rapidly lose polarity and differentiated function. This could be explained by gravity-induced sedimentation, which prevents formation of complete three-dimensional (3D) cell-cell/cellmatrix interactions and disrupts integrin-mediated signals (including the most abundant hepatic integrin alpha(5)beta(1)), important for cellular polarity and differentiation. Cell culture in a low fluid shear modelled microgravity (about 10(-2) g) environment p...

  13. Interferon Beta-1b Injection

    Interferon beta-1b injection is used to reduce episodes of symptoms in patients with relapsing-remitting (course ... and problems with vision, speech, and bladder control). Interferon beta-1b is in a class of medications ...

  14. Chondroitin sulfate proteoglycans regulate the growth, differentiation and migration of multipotent neural precursor cells through the integrin signaling pathway

    Lü He-Zuo


    Full Text Available Abstract Background Neural precursor cells (NPCs are defined by their ability to proliferate, self-renew, and retain the potential to differentiate into neurons and glia. Deciphering the factors that regulate their behaviors will greatly aid in their use as potential therapeutic agents or targets. Chondroitin sulfate proteoglycans (CSPGs are prominent components of the extracellular matrix (ECM in the central nervous system (CNS and are assumed to play important roles in controlling neuronal differentiation and development. Results In the present study, we demonstrated that CSPGs were constitutively expressed on the NPCs isolated from the E16 rat embryonic brain. When chondroitinase ABC was used to abolish the function of endogenous CSPGs on NPCs, it induced a series of biological responses including the proliferation, differentiation and migration of NPCs, indicating that CSPGs may play a critical role in NPC development and differentiation. Finally, we provided evidence suggesting that integrin signaling pathway may be involved in the effects of CSPGs on NPCs. Conclusion The present study investigating the influence and mechanisms of CSPGs on the differentiation and migration of NPCs should help us to understand the basic biology of NPCs during CNS development and provide new insights into developing new strategies for the treatment of the neurological disorders in the CNS.

  15. Differential gene expression by integrin β7+ and β7- memory T helper cells

    Yang Yee


    Full Text Available Abstract Background The cell adhesion molecule integrin α4β7 helps direct the migration of blood lymphocytes to the intestine and associated lymphoid tissues. We hypothesized that β7+ and β7- blood memory T helper cells differ in their expression of genes that play a role in the adhesion or migration of T cells. Results RNA was prepared from β7+ and β7- CD4+ CD45RA- blood T cells from nine normal human subjects and analyzed using oligonucleotide microarrays. Of 21357 genes represented on the arrays, 16 were more highly expressed in β7+ cells and 18 were more highly expressed in β7- cells (≥1.5 fold difference and adjusted P + memory/effector T cells than on β7- cells. Conclusions Memory/effector T cells that express integrin β7 have a distinct pattern of expression of a set of gene transcripts. Several of these molecules can affect cell adhesion or chemotaxis and are therefore likely to modulate the complex multistep process that regulates trafficking of CD4+ memory T cell subsets with different homing behaviors.

  16. Can alterations in integrin and laminin-5 expression be used as markers of malignancy?

    Thorup, A K; Reibel, J; Schiødt, M;


    Development of squamous cell carcinomas (SCCs) involves alterations in the adhesive interactions in the epithelium and invasion through the basement membrane. Therefore, changes in the expression of receptors and ligands involved in cell-cell and cell-matrix adhesion may be essential for the...... transformation of a premalignant into a malignant lesion. The aim of this study was to examine if expression of specific cell adhesion molecules can be used as markers of malignant development. By immunohistochemistry, we examined the expression pattern of integrins alpha2beta1, alpha3beta1, alpha6beta4 and...... laminin-5 in biopsies from SCCs (n=18), premalignant lesions (leukoplakias, n=21) and non-premalignant tissue with chronic inflammation (n=11). In poorly differentiated SCCs, patchy loss of alpha3beta1, alpha6beta4 and laminin-5 expression was pronounced at the invasion front, whereas there was a tendency...

  17. Increased Osteogenic Differentiation of Periodontal Ligament Stem Cells on Polydopamine Film Occurs via Activation of Integrin and PI3K Signaling Pathways

    Jeong Seok Lee


    Full Text Available Background/Aims: Mussel-inspired polydopamine (PDA is known to be an effective bioadhesive and bioactive material for controlling stem cell fate, which is important in stem cell-based regenerative medicine; however, the effect of PDA on osteogenic differentiation of periodontal ligament stem cells (PDLSCs is not fully understood. In this study, we investigated the osteoinductive effect of PDA on PDLSCs and examined how this phenomenon is encouraged. Methods: Osteogenic induction of PDLSCs was established by culturing cells on PDA film or on an uncoated polystyrene surface as a control. Osteogenic differentiation of PDLSCs was assessed by measurement of intracellular calcium levels and alkaline phosphatase (ALP activity as well as by evaluation of protein expression of osteocalcin (OCN, osterix (OSX, and runt-related transcription factor 2 (RUNX2. Results: The PDLSCs cultured on PDA film showed higher osteogenic activity than those on the control surface. Moreover, PDLSCs on PDA film expressed increased levels of the integrin adhesion receptors integrin α5 and β1 compared to control cells. Expression of one isoform of the intracellular signaling protein phosphatidylinositol-3-kinase (PI3K, p110γ, was increased in PDLSCs on PDA film in a PDA dose-dependent manner. This signaling protein was found to interact with integrin β1, demonstrating integrin-linked PI3K activation in response to PDA. Finally, the blockage of PI3K reduced the PDA-induced osteogenic activity of PDLSCs. Conclusion: our findings suggest that the bioadhesive PDA stimulates osteogenic differentiation of PDLSCs via activation of the integrin α5/β1 and PI3K signaling pathways.

  18. Targeted disruption of the LAMA3 gene in mice reveals abnormalities in survival and late stage differentiation of epithelial cells.

    Ryan, M C; Lee, K; Miyashita, Y; Carter, W G


    Laminin 5 regulates anchorage and motility of epithelial cells through integrins alpha6beta4 and alpha3beta1, respectively. We used targeted disruption of the LAMA3 gene, which encodes the alpha3 subunit of laminin 5 and other isoforms, to examine developmental functions that are regulated by adhesion to the basement membrane (BM). In homozygous null animals, profound epithelial abnormalities were detected that resulted in neonatal lethality, consistent with removal of all alpha3-laminin isoforms from epithelial BMs. Alterations in three different cellular functions were identified. First, using a novel tissue adhesion assay, we found that the mutant BM could not induce stable adhesion by integrin alpha6beta4, consistent with the presence of junctional blisters and abnormal hemidesmosomes. In the absence of laminin 5 function, we were able to detect a new ligand for integrin alpha3beta1 in the epidermal BM, suggesting that basal keratinocytes can utilize integrin alpha3beta1 to interact with an alternative ligand. Second, we identified a survival defect in mutant epithelial cells that could be rescued by exogenous laminin 5, collagen, or an antibody against integrin alpha6beta4, suggesting that signaling through beta1 or beta4 integrins is sufficient for survival. Third, we detected abnormalities in ameloblast differentiation in developing mutant incisors indicating that events downstream of adhesion are affected in mutant animals. These results indicate that laminin 5 has an important role in regulating tissue organization, gene expression, and survival of epithelium. PMID:10366601

  19. Muscle-specific integrins in masseter muscle fibers of chimpanzees: an immunohistochemical study.

    Gianluigi Vaccarino


    differentiation, and cell-extracellular matrix interactions. Our results demonstrated a different quantitative composition of integrins, in alpha male in respect to human and non-alpha male, hypothesizing that the MYH16 gene could modify the expression of integrins, influencing, in turn, the phenotype of muscle. In this way, alpha 7A-and beta 1A-integrin could determine the presence of type II fibers and then they could play a key role in the determination of contraction force. Then, MYH16 gene could be a common interactor of signalling between sarcoglycans and integrins in chimpanzee muscles.

  20. Differential Expression Levels of Integrin α6 Enable the Selective Identification and Isolation of Atrial and Ventricular Cardiomyocytes.

    Anne Maria Wiencierz

    Full Text Available Central questions such as cardiomyocyte subtype emergence during cardiogenesis or the availability of cardiomyocyte subtypes for cell replacement therapy require selective identification and purification of atrial and ventricular cardiomyocytes. However, current methodologies do not allow for a transgene-free selective isolation of atrial or ventricular cardiomyocytes due to the lack of subtype specific cell surface markers.In order to develop cell surface marker-based isolation procedures for cardiomyocyte subtypes, we performed an antibody-based screening on embryonic mouse hearts. Our data indicate that atrial and ventricular cardiomyocytes are characterized by differential expression of integrin α6 (ITGA6 throughout development and in the adult heart. We discovered that the expression level of this surface marker correlates with the intracellular subtype-specific expression of MLC-2a and MLC-2v on the single cell level and thereby enables the discrimination of cardiomyocyte subtypes by flow cytometry. Based on the differential expression of ITGA6 in atria and ventricles during cardiogenesis, we developed purification protocols for atrial and ventricular cardiomyocytes from mouse hearts. Atrial and ventricular identities of sorted cells were confirmed by expression profiling and patch clamp analysis.Here, we introduce a non-genetic, antibody-based approach to specifically isolate highly pure and viable atrial and ventricular cardiomyocytes from mouse hearts of various developmental stages. This will facilitate in-depth characterization of the individual cellular subsets and support translational research applications.

  1. Differential β3 and β1 Integrin Expression in Bone Marrow and Cortical Bone of Estrogen Deficient Rats.

    Voisin, Muriel; McNamara, Laoise M


    Integrin-based (β3 ) attachments to the extracellular matrix (ECM) on osteocyte cell processes have recently been proposed to play an important role in facilitating osteocyte mechanosensation. However, it is not yet known whether integrin expression is altered in the mechanoregulatory osteocytes during osteoporosis. The objective of this study was to test the hypothesis that the expression of integrin-based mechanosensory complexes (β1 and β3 integrins) is altered as a direct response to estrogen deficiency, in an estrogen deficient animal model of osteoporosis. Four weeks post-operatively, immunohistochemistry was used to detect for β1 and β3 integrin subunits in bone tissue and marrow of ovariectomized (OVX; N = 4) and SHAM (N = 4) operated animals. A tartrate resistant acid phosphatase (TRAP) control stain was performed to quantify the presence of osteoclasts in the bone marrow and bone surfaces. Image analysis was performed to quantify expression patterns in different biological compartments, that is, bone marrow, endosteum, and cortical bone. Our results showed that β1 integrins were ubiquitously expressed throughout the bone and marrow, for both OVX and SHAM groups. β3 integrin subunit expression was lower in bone cells from osteoporotic animals compared to controls, whereas β3 expression in marrow cells did not differ significantly between groups. At the endosteum no difference was observed in β3 integrin subunit expression. As expected, the number of osteoclasts was higher in the OVX group validating an imbalance in bone remodeling. We propose that a reduction in β3 integrin expression in osteocytes might impair mechanosensation by bone cells during estrogen deficiency. PMID:25974241

  2. Laminin isoforms differentially regulate adhesion, spreading, proliferation, and ERK activation of β1 integrin-null cells

    The presence of many laminin receptors of the β1 integrin family on most cells makes it difficult to define the biological functions of other major laminin receptors such as integrin α6β4 and dystroglycan. We therefore tested the binding of a β1 integrin-null cell line GD25 to four different laminin variants. The cells were shown to produce dystroglycan, which based on affinity chromatography bound to laminin-1, -2/4, and -10/11, but not to laminin-5. The cells also expressed the integrin α6Aβ4A variant. GD25 β1 integrin-null cells are known to bind poorly to laminin-1, but we demonstrate here that these cells bind avidly to laminin-2/4, -5, and -10/11. The initial binding at 20 min to each of these laminins could be inhibited by an integrin α6 antibody, but not by a dystroglycan antibody. Hence, integrin α6Aβ4A of GD25 cells was identified as a major receptor for initial GD25 cell adhesion to three out of four tested laminin isoforms. Remarkably, cell adhesion to laminin-5 failed to promote cell spreading, proliferation, and extracellular signal-regulated kinase (ERK) activation, whereas all these responses occurred in response to adhesion to laminin-2/4 or -10/11. The data establish GD25 cells as useful tools to define the role integrin α6Aβ4A and suggest that laminin isoforms have distinctly different capacities to promote cell adhesion and signaling via integrin α6Aβ4A

  3. Adipose Tissue-Derived Stromal Cells Inhibit TGF-beta 1-Induced Differentiation of Human Dermal Fibroblasts and Keloid Scar-Derived Fibroblasts in a Paracrine Fashion

    Spiekman, Maroesjka; Przybyt, Ewa; Plantinga, Josee A.; Gibbs, Susan; van der Lei, Berend; Harmsen, Martin C.


    Background: Adipose tissue-derived stromal cells augment wound healing and skin regeneration. It is unknown whether and how they can also influence dermal scarring. The authors hypothesized that adipose tissue-derived stromal cells inhibit adverse differentiation of dermal fibroblasts induced by the

  4. Integrin binding specificity regulates biomaterial surface chemistry effects on cell differentiation

    Keselowsky, Benjamin G.; Collard, David M.; Andrés J. García


    Biomaterial surface chemistry has profound consequences on cellular and host responses, but the underlying molecular mechanisms remain poorly understood. Using self-assembled monolayers as model biomaterial surfaces presenting well defined chemistries, we demonstrate that surface chemistry modulates osteoblastic differentiation and matrix mineralization independently from alterations in cell proliferation. Surfaces were precoated with equal densities of fibronectin (FN), and surface chemistry...

  5. Mouse-induced pluripotent stem cells differentiate into odontoblast-like cells with induction of altered adhesive and migratory phenotype of integrin.

    Nobuaki Ozeki

    Full Text Available Methods for differentiating induced pluripotent stem (iPS cells into odontoblasts generally require epithelial-mesenchymal interactions. Here, we sought to characterize the cells produced by a 'hanging drop' technique for differentiating mouse iPS cells into odontoblast-like cells that requires no such interaction. Cells were cultured by the hanging drop method on a collagen type-I (Col-I scaffold (CS combined with bone morphogenetic protein (BMP-4 (CS/BMP-4 without an epithelial-mesenchymal interaction. We evaluated the expression of odontoblast-related mRNA and protein, and the proliferation rate of these cells using reverse-transcription polymerase chain reaction, immunofluorescence staining, and BrdU cell proliferation enzyme-linked immunosorbent assay, respectively. The differentiated cells strongly expressed the mRNA for dentin sialophosphoprotein (DSPP and dentin matrix protein-1 (Dmp-1, which are markers of mature odontoblasts. Osteopontin and osteocalcin were not expressed in the differentiated cells, demonstrating that the differentiated iPS cells bore little resemblance to osteoblasts. Instead, they acquired odontoblast-specific properties, including the adoption of an odontoblastic phenotype, typified by high alkaline phosphatase (ALP activity and calcification capacity. The cell-surface expression of proteins such as integrins α2, α6, αV and αVβ3 was rapidly up-regulated. Interestingly, antibodies and siRNAs against integrin α2 suppressed the expression of DSPP and Dmp-1, reduced the activity of ALP and blocked calcification, suggesting that integrin α2 in iPS cells mediates their differentiation into odontoblast-like cells. The adhesion of these cells to fibronectin and Col-I, and their migration on these substrata, was significantly increased following differentiation into odontoblast-like cells. Thus, we have demonstrated that integrin α2 is involved in the differentiation of mouse iPS cells into odontoblast-like cells

  6. Differential Dynamics of α5 Integrin, Paxillin, and α-Actinin during Formation and Disassembly of Adhesions in Migrating Cells

    Laukaitis, Christina M; Webb, Donna J.; Donais, Karen; Horwitz, Alan F.


    To investigate the mechanisms by which adhesions form and disperse in migrating cells, we expressed α5 integrin, α-actinin, and paxillin as green fluorescent protein (GFP) fusions. All localized with their endogenous counterparts and did not perturb migration when expressed at moderate levels. α5-GFP also rescued the adhesive defects in CHO B2 cells, which are α5 integrin deficient. In ruffling cells, α5-GFP and α-actinin–GFP localized prominently at the leading edge in membrane protrusions. ...

  7. Spermidine/spermine N-1-acetyltransferase specifically binds to the integrin alpha 9 subunit cytoplasmic domain and enhances cell migration

    Chen, C.; Young, B A; Coleman, C S; Pegg, A E; Sheppard, D


    T he integrin alpha9beta1 is expressed on migrating cells, such as leukocytes, and binds to multiple ligands that are present at sites of tissue injury and inflammation. alpha9beta1, like the structurally related integrin alpha4beta1, mediates accelerated cell migration, an effect that depends on the beta cytoplasmic domain. alpha4beta1 enhances migration through reversible binding to the adapter protein, paxillin, but alpha9beta1-dependent migration is paxillin independent. Using yeast two-h...

  8. Absence of alphavbeta6 integrin is linked to initiation and progression of periodontal disease.

    Ghannad, Farzin; Nica, Daniela; Fulle, Maria I Garcia; Grenier, Daniel; Putnins, Edward E; Johnston, Sarah; Eslami, Ameneh; Koivisto, Leeni; Jiang, Guoqiao; McKee, Marc D; Häkkinen, Lari; Larjava, Hannu


    Integrin alphavbeta6 is generally not expressed in adult epithelia but is induced in wound healing, cancer, and certain fibrotic disorders. Despite this generalized absence, we observed that alphavbeta6 integrin is constitutively expressed in the healthy junctional epithelium linking the gingiva to tooth enamel. Moreover, expression of alphavbeta6 integrin was down-regulated in human periodontal disease, a common medical condition causing tooth loss and also contributing to the development of cardiovascular diseases by increasing the total systemic inflammatory burden. Remarkably, integrin beta6 knockout mice developed classic signs of spontaneous, chronic periodontal disease with characteristic inflammation, epithelial down-growth, pocket formation, and bone loss around the teeth. Integrin alphavbeta6 acts as a major activator of transforming growth factor-beta1 (TGF-beta1), a key anti-inflammatory regulator in the immune system. Co-expression of TGF-beta1 and alphavbeta6 integrin was observed in the healthy junctional epithelium. Moreover, an antibody that blocks alphavbeta6 integrin-mediated activation of TGF-beta1 initiated inflammatory periodontal disease in a rat model of gingival inflammation. Thus, alphavbeta6 integrin is constitutively expressed in the epithelium sealing the gingiva to the tooth and plays a central role in protection against inflammatory periodontal disease through activation of TGF-beta1. PMID:18385522

  9. EDA-containing cellular fibronectin induces fibroblast differentiation through binding to alpha4beta7 integrin receptor and MAPK/Erk 1/2-dependent signaling.

    Kohan, Martin; Muro, Andres F; White, Eric S; Berkman, Neville


    Fibroblast differentiation is an essential step during wound healing and fibrosis. Fibronectin (FN) is a major component of the extracellular matrix and occurs in two main forms: plasma and cellular FN. The latter includes the alternatively spliced domain A (EDA). Although EDA-containing cellular fibronectin (EDA-FN) is associated with fibroblast differentiation, how EDA-FN promotes differentiation is incompletely understood. In this study, we investigate the mechanism by which EDA-FN contributes to fibroblast differentiation with emphasis on the characterization of the EDA-FN receptor. We show that EDA-FN increases α-SMA expression (immunofluorescence), collagen deposition, cell contractility, and focal adhesion kinase (FAK) activation (immunoblotting); whereas plasma FN, a form lacking EDA, shows no effect. Primary lung fibroblasts constitutively express α(4)β(7) integrin receptor (FACS and RT-PCR). Blocking of α(4)β(7) reduces fibroblast adhesion to EDA-FN and inhibits α-SMA expression, collagen deposition, and FAK activation induced by EDA-FN. Using recombinant EDA-containing peptides, we demonstrate that the EDA segment is sufficient to induce fibroblast differentiation via binding to α(4)β(7). EDA-FN induces MAPK-Erk1/2 activation and inhibition of MEK1/2 attenuates EDA-FN-induced α-SMA expression. Our findings demonstrate that EDA-FN induces fibroblast differentiation by a mechanism that involves binding of EDA to α(4)β(7) integrin followed by activation of FAK and MAPK-associated signaling pathways. PMID:20643910

  10. Interferon Beta-1a Intramuscular Injection

    Interferon beta-1a intramuscular injection is used to reduce the number of episodes of symptoms and slow ... and problems with vision, speech, and bladder control). Interferon beta-1a is in a class of medications ...

  11. Interferon Beta-1a Subcutaneous Injection

    Interferon beta-1a subcutaneous injection is used to reduce episodes of symptoms and slow the development of ... and problems with vision, speech, and bladder control). Interferon beta-1a is in a class of medications ...

  12. Interferon Beta-1a Intramuscular Injection

    Interferon beta-1a intramuscular injection is used to reduce the number of episodes of symptoms and slow the development of disability in patients ... Interferon beta-1a intramuscular injection comes as a powder in vials to be mixed into a solution for injection. Interferon beta-1a intramuscular ...

  13. Recombinant human laminin-10 (alpha5beta1gamma1). Production, purification, and migration-promoting activity on vascular endothelial cells.

    Doi, Masayuki; Thyboll, Jill; Kortesmaa, Jarkko; Jansson, Katarina; Iivanainen, Antti; Parvardeh, Masomeh; Timpl, Rupert; Hedin, Ulf; Swedenborg, Jesper; Tryggvason, Karl


    The laminin (LN) family of large heterotrimeric extracellular matrix glycoproteins has multiple functions: LNs take part in the regulation of processes such as cell migration, differentiation, and proliferation, in addition to contributing to the structure of basement membranes. LN-10, composed of alpha5, beta1, and gamma1 chains, is widely distributed in most basement membranes of both epithelia and endothelia. We determined the complete human cDNA sequence for the LN alpha5 chain and produced recombinant human LN-10 (rLN-10) in HEK293 cells by triple transfection of full-length cDNAs encoding the human LN alpha5, beta1, and gamma1 chains. The rLN-10 was purified using affinity chromatography and had an apparent molecular mass of approximately 800 kDa in SDS-PAGE and a native domain structure in rotary shadowing electron microscopy. By using function-blocking monoclonal antibodies, integrin alpha(3)beta(1) was found to be a major mediator of adhesion of HT-1080 and human saphenous vein endothelial cells. Human saphenous vein endothelial cells adhered more strongly to rLN-10 than to LN-1 and LN-8 and showed better migration on rLN-10, compared with several other matrices. Considering the cell adhesive and migration-promoting properties of rLN-10 on endothelial cells, this molecule could be useful in improving the biocompatibility and endothelialization of vascular grafts. PMID:11821406

  14. Disintegrins: integrin selective ligands which activate integrin-coupled signaling and modulate leukocyte functions

    Barja-Fidalgo C.


    Full Text Available Extracellular matrix proteins and cell adhesion receptors (integrins play essential roles in the regulation of cell adhesion and migration. Interactions of integrins with the extracellular matrix proteins lead to phosphorylation of several intracellular proteins such as focal adhesion kinase, activating different signaling pathways responsible for the regulation of a variety of cell functions, including cytoskeleton mobilization. Once leukocytes are guided to sites of infection, inflammation, or antigen presentation, integrins can participate in the initiation, maintenance, or termination of the immune and inflammatory responses. The modulation of neutrophil activation through integrin-mediated pathways is important in the homeostatic control of the resolution of inflammatory states. In addition, during recirculation, T lymphocyte movement through distinct microenvironments is mediated by integrins, which are critical for cell cycle, differentiation and gene expression. Disintegrins are a family of low-molecular weight, cysteine-rich peptides first identified in snake venom, usually containing an RGD (Arg-Gly-Asp motif, which confers the ability to selectively bind to integrins, inhibiting integrin-related functions in different cell systems. In this review we show that, depending on the cell type and the microenvironment, disintegrins are able to antagonize the effects of integrins or to act agonistically by activating integrin-mediated signaling. Disintegrins have proven useful as tools to improve the understanding of the molecular events regulated by integrin signaling in leukocytes and prototypes in order to design therapies able to interfere with integrin-mediated effects.

  15. Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression

    Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J


    Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

  16. [Transforming growth factor beta-1: structure, function, and regulation mechanisms in cancer].

    Peralta-Zaragoza, O; Lagunas-Martínez, A; Madrid-Marina, V


    Transforming growth factor beta-1 (TGF-beta 1) is produced by several cell lineages such as lymphocytes, macrophages, and dendritic cells, and its expression serves in both autocrine and paracrine modes to control the differentiation, proliferation, and state of activation of these and other cells. In general, TGF-beta 1 has pleiotropic properties on the immune response during the development of infection diseases and cancer; however, the mechanisms of action and regulation of gene expression of this cytokine are poorly understood, in this review, the biological properties and the molecular mechanisms that regulate TGF-beta 1 gene expression are described, to understand the role of this cytokine in growth and cell differentiation. The knowledge of molecular mechanisms of gene expression of TGF-beta 1 may serve to develop new cancer therapies. The English version of this paper is available at: PMID:11547595

  17. Intestinal epithelial restitution. Involvement of specific laminin isoforms and integrin laminin receptors in wound closure of a transformed model epithelium

    Lotz, M M; Nusrat, A; Madara, J L;


    cells adjoining wounds. Because T84 cells stained faintly with MAbs 4C7 (laminin alpha 1 subunit) and with MAbs 4F11 and 1B4 (laminin alpha 2 subunit), we suggest that expression of laminins 6 and 7 is enhanced in response to wounding. The alpha 3 beta 1 integrin and the alpha 6-containing integrins...

  18. INDUCCIÓN DIFERENCIAL DE POLIFENOLOXIDASA Y beta-1,3-GLUCANASA EN CLAVEL (Dianthus caryophyllus DURANTE LA INFECCIÓN POR Fusarium oxysporum f. sp. dianthi RAZA 2 Polyphenoloxidase and beta-1,3-Glucanase Differential Induction in Carnation (Dianthus caryophyllus Infectedby Fusarium oxysporum f. sp. dianthi race 2


    Full Text Available Se evaluó el cambio en el comportamiento de las enzimas polifenoloxidasa (PFO y beta-1,3-glucanasa (Glu en tallos de plantas de clavel inoculadas con el patógeno Fusarium oxysporum f. sp. dianthi (Fod raza 2, con el fin de determinar su posible participación en la respuesta defensiva y en la resistencia de la planta al marchitamiento vascular. Se evaluaron parámetros para la extracción y determinación de actividad de dichas enzimas. Las condiciones que proporcionaron los mejores resultados de extracción fueron: obtención de polvos de acetona previa al tratamiento con buffer de fosfatos pH 6,5 con 3% de PVPP para PFO y con buffer de fosfatos pH 6,5 para Glu. La cuantificación de PFO se llevó a cabo usando catecol a pH 7,0 y 37 ºC y midiendo los productos de reacción a 420 nm, y la de Glu usando laminarina digitata a 37 ºC y pH 5,5. Una vez establecidos los métodos, esquejes de clavel de una variedad altamente tolerante (Carolina y de una susceptible (Uconn fueron inoculados con el patógeno y sometidos al análisis de las enzimas a diferentes tiempos post-inoculación. Mientras que en la variedad susceptible la actividad PFO no se vio afectada, en la tolerante se presentó una importante y significativa inducción de esta enzima a las 12 h y 24 h, indicando que puede desempeñar un papel clave en la defensa de la planta, en fenómenos metabólicos probablemente relacionados con lignificación y síntesis de fenólicos. La enzima Glu presentó inducción en ambas variedades, aunque a diferentes tiempos, lo cual hace parte de una respuesta metabólica inespecífica, no relacionada con mecanismos de defensa activa del clavel contra el patógeno causal del marchitamiento vascular.We evaluated the changes on the dynamics of polyphenoloxidase (PFO and beta-1,3-glucanase (Glu enzymes in carnation steems, which had been previously inoculated with the pathogen Fusarium oxysporum f. sp. dianthi race 2 (Fod. We established the experimental

  19. Monocytic cells synthesize, adhere to, and migrate on laminin-8 (alpha 4 beta 1 gamma 1).

    Pedraza, C; Geberhiwot, T; Ingerpuu, S; Assefa, D; Wondimu, Z; Kortesmaa, J; Tryggvason, K; Virtanen, I; Patarroyo, M


    Laminins, a growing family of large heterotrimeric proteins with cell adhesive and signaling properties, are major components of vascular and other basement membranes. Expression, recognition, and use of laminin isoforms by leukocytes are poorly understood. In monoblastic THP-1 cells, transcripts for laminin gamma(1)-, beta(1)-, and alpha(4)-chains were detected by RT-PCR. Following immunoaffinity purification on a laminin beta(1) Ab-Sepharose column, laminin beta(1)- (220 kDa), gamma(1)- (200 kDa), and alpha(4)- (180/200 kDa) chains were detected by Western blotting in THP-1 cells and in two other monoblastic cell lines, U-937 and Mono Mac 6. After cell permeabilization, a mAb to laminin gamma(1)-chain reacted with practically all blood monocytes by immunofluorescence flow cytometry, and laminin-8 (alpha(4)beta(1)gamma(1)) could be isolated also from these cells. Monoblastic JOSK-I cells adhered constitutively to immobilized recombinant laminin-8, less than to laminin-10/11 (alpha(5)beta(1)gamma(1)/alpha(5)beta(2)gamma(1)) but to a higher level than to laminin-1 (alpha(1)beta(1)gamma(1)). Compared with the other laminin isoforms, adhesion to laminin-8 was preferentially mediated by alpha(6)beta(1) and beta(2) integrins. Laminin-8 and, to a lower extent, laminin-1 promoted spontaneous and chemokine-induced migration of blood monocytes, whereas laminin-10/11 was inhibitory. Altogether, the results indicate that leukocytes, as other cell types, are able to synthesize complete laminin molecules. Expression, recognition, and use of laminin-8 by leukocytes suggest a major role of this laminin isoform in leukocyte physiology. PMID:11067943

  20. Alterations in integrin expression modulates invasion of pancreatic cancer cells.

    Walsh, Naomi


    BACKGROUND: Factors mediating the invasion of pancreatic cancer cells through the extracellular matrix (ECM) are not fully understood. METHODS: In this study, sub-populations of the human pancreatic cancer cell line, MiaPaCa-2 were established which displayed differences in invasion, adhesion, anoikis, anchorage-independent growth and integrin expression. RESULTS: Clone #3 displayed higher invasion with less adhesion, while Clone #8 was less invasive with increased adhesion to ECM proteins compared to MiaPaCa-2. Clone #8 was more sensitive to anoikis than Clone #3 and MiaPaCa-2, and displayed low colony-forming efficiency in an anchorage-independent growth assay. Integrins beta 1, alpha 5 and alpha 6 were over-expressed in Clone #8. Using small interfering RNA (siRNA), integrin beta1 knockdown in Clone #8 cells increased invasion through matrigel and fibronectin, increased motility, decreased adhesion and anoikis. Integrin alpha 5 and alpha 6 knockdown also resulted in increased motility, invasion through matrigel and decreased adhesion. CONCLUSION: Our results suggest that altered expression of integrins interacting with different extracellular matrixes may play a significant role in suppressing the aggressive invasive phenotype. Analysis of these clonal populations of MiaPaCa-2 provides a model for investigations into the invasive properties of pancreatic carcinoma.

  1. Human liver alcohol dehydrogenase. 1. The primary structure of the beta 1 beta 1 isoenzyme.

    Hempel, J; Bühler, R; Kaiser, R; Holmquist, B; de Zalenski, C; von Wartburg, J P; Vallee, B; Jörnvall, H


    Determination of the amino acid sequence of the beta 1 subunit from the class I (pyrazole-sensitive) human liver alcohol dehydrogenase isoenzyme beta 1 beta 1 revealed a 373-residue structure differing at 48 positions (including a gap) from that of the subunit of the well studied horse liver alcohol dehydrogenase EE isoenzyme. The structure deduced is compatible with known differences in composition, ultraviolet absorbance, electrophoretic mobility and catalytic properties between the horse and human enzymes. All zinc-liganding residues of the horse E subunit are strictly conserved in the human beta 1 subunit, despite an earlier report of a mutation involving Cys-46. This residue therefore remains conserved in all known alcohol dehydrogenase structures. However, the total cysteine content of the beta 1 structure is raised from 14 in the subunit of the horse enzyme to 15 by a Tyr----Cys exchange. Most exchanges are on the surface of the molecule and of a well conserved nature. Substitutions close to the catalytic centre are of interest to explain the altered substrate specificity and different catalytic activity of the beta 1 homodimer. Functionally, a Ser----Thr exchange at position 48 appears to be of special importance, since Thr-48 in beta 1 instead of Ser-48 in the horse enzyme can restrict available space. Four other substitutions also line the active-site pocket, and appear to constitute partly compensated exchanges. PMID:6391920

  2. IGF-I and TGF-beta1 have distinct effects on phenotype and proliferation of intestinal fibroblasts.

    Simmons, James G; Pucilowska, Jolanta B; Keku, Temitope O; Lund, P Kay


    Insulin-like growth factor I (IGF-I) and transforming growth factor-beta1 (TGF-beta1) are upregulated in myofibroblasts at sites of fibrosis in experimental enterocolitis and in Crohn's disease (CD). We compared the sites of expression of IGF-I and TGF-beta1 in a rat peptidoglycan-polysaccharide (PG-PS) model of chronic granulomatous enterocolitis and fibrosis. We used the human colonic CCD-18Co fibroblast/myofibroblast cell line to test the hypothesis that TGF-beta1 and IGF-I interact to regulate proliferation, collagen synthesis, and activated phenotype typified by expression of alpha-smooth muscle actin and organization into stress fibers. IGF-I potently stimulated while TGF-beta1 inhibited basal DNA synthesis. TGF-beta1 and IGF-I each had similar but not additive effects to induce type I collagen. TGF-beta1 but not IGF-I potently stimulated expression of alpha-smooth muscle actin and stress fiber formation. IGF-I in combination with TGF-beta1 attenuated stress fiber formation without reducing alpha-smooth muscle actin expression. Stress fibers were not a prerequisite for increased collagen synthesis. TGF-beta1 upregulated IGF-I mRNA, which led us to examine the effects of IGF-I in cells previously activated by TGF-beta1 pretreatment. IGF-I potently stimulated proliferation of TGF-beta1-activated myofibroblasts without reversing activated fibrogenic phenotype. We conclude that TGF-beta1 and IGF-I both stimulate type I collagen synthesis but have differential effects on activated phenotype and proliferation. We propose that during intestinal inflammation, regulation of activated phenotype and proliferation may require sequential actions of TGF-beta1 and IGF-I, but they may act in concert to increase collagen deposition. PMID:12181198

  3. TGF-beta1 release from biodegradable polymer microparticles: its effects on marrow stromal osteoblast function

    Lu, L.; Yaszemski, M. J.; Mikos, A. G.; McIntire, L. V. (Principal Investigator)


    BACKGROUND: Controlled release of transforming growth factor-beta1 (TGF-beta1) to a bone defect may be beneficial for the induction of a bone regeneration cascade. The objectives of this work were to assess the feasibility of using biodegradable polymer microparticles as carriers for controlled TGF-beta1 delivery and the effects of released TGF-beta1 on the proliferation and differentiation of marrow stromal cells in vitro. METHODS: Recombinant human TGF-beta1 was incorporated into microparticles of blends of poly(DL-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG). Fluorescein isothiocynate-labeled bovine serum albumin (FITC-BSA) was co-encapsulated as a porogen. The effects of PEG content (0, 1, or 5% by weight [wt%]) and buffer pH (3, 5, or 7.4) on the protein release kinetics and the degradation of PLGA were determined in vitro for as long as 28 days. Rat marrow stromal cells were seeded on a biodegradable poly(propylene fumarate) (PPF) substrate. The dose response and biological activity of released TGF-beta1 was determined after 3 days in culture. The effects of TGF-beta1 released from PLGA/PEG microparticles on marrow stromal cell proliferation and osteoblastic differentiation were assessed during a 21-day period. RESULTS: TGF-beta1 was encapsulated along with FITC-BSA into PLGA/PEG blend microparticles and released in a multiphasic fashion including an initial burst for as long as 28 days in vitro. Increasing the initial PEG content resulted in a decreased cumulative mass of released proteins. Aggregation of FITC-BSA occurred at lower buffer pH, which led to decreased release rates of both proteins. The degradation of PLGA was increased at higher PEG content and significantly accelerated at acidic pH conditions. Rat marrow stromal cells cultured on PPF substrates showed a dose response to TGF-beta1 released from the microparticles similar to that of added TGF-beta1, indicating that the activity of TGF-beta1 was retained during microparticle

  4. Integrin Trafficking and Tumor Progression

    Sejeong Shin


    Full Text Available Integrins are major mediators of cancer cell adhesion to extracellular matrix. Through this interaction, integrins play critical roles in cell migration, invasion, metastasis, and resistance to apoptosis during tumor progression. Recent studies highlight the importance of integrin trafficking, endocytosis and recycling, for the functions of integrins in cancer cells. Understanding the molecular mechanisms of integrin trafficking is pivotal for understanding tumor progression and for the development of anticancer drugs.

  5. Breast Cancer Cells in Three-dimensional Culture Display an Enhanced Radioresponse after Coordinate Targeting of Integrin ?5?1 and Fibronectin

    Nam, Jin-Min; Onodera, Yasuhito; Bissell, Mina J; Park, Catherine C


    Tactics to selectively enhance cancer radioresponse are of great interest. Cancer cells actively elaborate and remodel their extracellular matrix (ECM) to aid in survival and progression. Previous work has shown that {beta}1-integrin inhibitory antibodies can enhance the growth-inhibitory and apoptotic responses of human breast cancer cell lines to ionizing radiation, either when cells are cultured in three-dimensional laminin-rich ECM (3D lrECM) or grown as xenografts in mice. Here, we show that a specific {alpha} heterodimer of {beta}1-integrin preferentially mediates a prosurvival signal in human breast cancer cells that can be specifically targeted for therapy. 3D lrECM culture conditions were used to compare {alpha}-integrin heterodimer expression in malignant and nonmalignant cell lines. Under these conditions, we found that expression of {alpha}5{beta}1-integrin was upregulated in malignant cells compared with nonmalignant breast cells. Similarly, we found that normal and oncofetal splice variants of fibronectin, the primary ECM ligand of {alpha}5{beta}1-integrin, were also strikingly upregulated in malignant cell lines compared with nonmalignant acini. Cell treatment with a peptide that disrupts the interactions of {alpha}5{beta}1-integrin with fibronectin promoted apoptosis in malignant cells and further heightened the apoptotic effects of radiation. In support of these results, an analysis of gene expression array data from breast cancer patients revealed an association of high levels of {alpha}5-integrin expression with decreased survival. Our findings offer preclinical validation of fibronectin and {alpha}5{beta}1-integrin as targets for breast cancer therapy.

  6. Covisualization by computational optical-sectioning microscopy of integrin and associated proteins at the cell membrane of living onion protoplasts

    Gens, J. S.; Reuzeau, C.; Doolittle, K. W.; McNally, J. G.; Pickard, B. G.; Evans, M. L. (Principal Investigator)


    Using higher-resolution wide-field computational optical-sectioning fluorescence microscopy, the distribution of antigens recognized by antibodies against animal beta 1 integrin, fibronectin, and vitronectin has been visualized at the outer surface of enzymatically protoplasted onion epidermis cells and in depectinated cell wall fragments. On the protoplast all three antigens are colocalized in an array of small spots, as seen in raw images, in Gaussian filtered images, and in images restored by two different algorithms. Fibronectin and vitronectin but not beta 1 integrin antigenicities colocalize as puncta in comparably prepared and processed images of the wall fragments. Several control visualizations suggest considerable specifity of antibody recognition. Affinity purification of onion cell extract with the same anti-integrin used for visualization has yielded protein that separates in SDS-PAGE into two bands of about 105-110 and 115-125 kDa. These bands are again recognized by the visualization antibody, which was raised against the extracellular domain of chicken beta 1 integrin, and are also recognized by an antibody against the intracellular domain of chicken beta 1 integrin. Because beta 1 integrin is a key protein in numerous animal adhesion sites, it appears that the punctate distribution of this protein in the cell membranes of onion epidermis represents the adhesion sites long known to occur in cells of this tissue. Because vitronectin and fibronection are matrix proteins that bind to integrin in animals, the punctate occurrence of antigenically similar proteins both in the wall (matrix) and on enzymatically prepared protoplasts reinforces the concept that onion cells have adhesion sites with some similarity to certain kinds of adhesion sites in animals.

  7. Is Serum Transforming Growth Factor beta-1 Superior to Serum Creatinine for assessing Renal Failure and Renal Transplant Rejection

    Gyanendra Kumar Sonkar, Usha


    Full Text Available A sustained overexpression of Transforming Growth Factor beta1 (TGF beta1, a cytokine has beenimplicated in the pathogenesis of fibrosis of kidney leading to end stage . The main aim of present studywas to find the utility of TGF beta1 and serum creatinine in differentiating chronic renal failure (CRFfrom acute renal failure (ARF, renal transplant rejection (Tx Rej and stable renal transplant (Tx Stband to study has attempted histopathological correlation of rejection cases with TGF beta1 and serumcreatinine. TGF beta1 was determined by using ELISA and serum creatinine was done by autoanalyser.In normal healthy controls (NHC, in majority of cases (80.0% TGF beta1 was below 25 ng/ml while in6.0% cases it was upto 34 ng/ml. Rise of TGF beta1 was significant in CRF patients as compared to ARFand NHC (p<0.05 .In rejection cases, TGF beta1 level was significantly raised as compared to NHCand stable graft cases (p<0.05. In rejection cases, it was raised above 40 ng/ml in only 50% cases. In twocases inspite of more than 70% glomerular fibrosis, the patient had TGF beta1 level of only 5 ng/ml and inother three cases of acute cellular rejection the level was 70, 35 and 28 ng/ml respectively.Contrary to itserum creatinine was raised above 2 mg/dl in all cases of transplant rejection but in stable transplant casesin majority (70.6% it was below 1.5 mg/dl and in 5 cases it was between 1.5 – 1.9 mg/dl.Thus the studysuggests that TGF beta1 may not be a good marker for chronic transplant rejection, as it does notcorrelate well with glomerular fibrosis, probably it is more associated with interstitial inflammation but itcan differentiate CRF from ARF if cut off of 40 ng/ml is taken.

  8. Integrin-like proteins are localized to plasma membrane fractions, not plastids, in Arabidopsis

    Swatzell, L. J.; Edelmann, R. E.; Makaroff, C. A.; Kiss, J. Z.


    Integrins are a large family of integral membrane proteins that function in signal transduction in animal systems. These proteins are conserved in vertebrates, invertebrates, and fungi. Evidence from previous research suggests that integrin-like proteins may be present in plants as well, and that these proteins may function in signal transduction during gravitropism. In past studies, researchers have used monoclonal and polyclonal antibodies to localize beta 1 integrin-like proteins in plants. However, there is a disparity between data collected from these studies, especially since molecular weights obtained from these investigations range from 55-120 kDa for integrin-like proteins. To date, a complete investigation which employs all three basic immunolabeling procedures, immunoblotting, immunofluorescence microscopy, and immunogold labeling, in addition to extensive fractionation and exhaustive controls, has been lacking. In this paper, we demonstrate that use of a polyclonal antibody against the cytoplasmic domain of avian beta 1-integrin can produce potential artifacts in immunolocalization studies. However, these problems can be eliminated through use of starchless mutants or proper specimen preparation prior to electrophoresis. We also show that this antibody, when applied within the described parameters and with careful controls, identifies a large (100 kDa) integrin-like protein that is localized to plasma membrane fractions in Arabidopsis.

  9. Chondroitin sulphate modification in the alpha4 chain of human recombinant laminin-8 (alpha4beta1gamma1).

    Kortesmaa, Jarkko; Doi, Masayuki; Patarroyo, Manuel; Tryggvason, Karl


    We have produced human laminin-8 (alpha4beta1gamma1) using recombinant technology. Approximately half of the recombinant laminin-8 (rLN-8) molecules were found to have a chondroitin sulphate modification in the alpha4 chain. The substituted and non-substituted forms were separated and tested for cell adhesion activity. Lower cell adhesion promoting activity was seen for the substituted form, but the integrin receptor utilization was similar. We also found the human rLN-8 to behave identically in cell adhesion assays compared to a human/mouse hybrid variant of rLN-8. PMID:12392759

  10. An endothelial laminin isoform, laminin 8 (alpha4beta1gamma1), is secreted by blood neutrophils, promotes neutrophil migration and extravasation, and protects neutrophils from apoptosis.

    Wondimu, Zenebech; Geberhiwot, Tarekegn; Ingerpuu, Sulev; Juronen, Erkki; Xie, Xun; Lindbom, Lennart; Doi, Masayuki; Kortesmaa, Jarkko; Thyboll, Jill; Tryggvason, Karl; Fadeel, Bengt; Patarroyo, Manuel


    During extravasation, neutrophils migrate through the perivascular basement membrane (BM), a specialized extracellular matrix rich in laminins. Laminins 8 (LN-8) (alpha4beta1gamma1) and 10 (LN-10) (alpha5beta1gamma1) are major components of the endothelial BM, but expression, recognition, and use of these laminin isoforms by neutrophils are poorly understood. In the present study, we provide evidence, using a panel of novel monoclonal antibodies against human laminin alpha4 (LNalpha4) chain, that neutrophils contain and secrete LN-8, and that this endogenous laminin contributes to chemoattractant-induced, alphaMbeta2-integrin-dependent neutrophil migration through albumin-coated filters. Phorbol ester-stimulated neutrophils adhered to recombinant human (rh) LN-8, rhLN-10, and mouse LN-1 (mLN-1) (alpha1beta1gamma1) via alphaMbeta2-integrin, and these laminin isoforms strongly promoted chemoattractant-induced neutrophil migration via the same integrin. However, only rhLN-8 enhanced the spontaneous migration. In addition, recruitment of neutrophils into the peritoneum following an inflammatory stimulus was impaired in LNalpha4-deficient mice. rhLN-8 also protected isolated neutrophils from spontaneous apoptosis. This study is the first to identify a specific laminin isoform in neutrophils and provides evidence for the role of LN-8 in the adhesion, migration, extravasation, and survival of these cells. PMID:15172971

  11. Pulmonary administration of integrin-nanoparticles regenerates collapsed alveoli.

    Horiguchi, Michiko; Kojima, Hisako; Sakai, Hitomi; Kubo, Hiroshi; Yamashita, Chikamasa


    Chronic obstructive pulmonary disease (COPD) is an intractable pulmonary disease, causes widespread and irreversible alveoli collapse. In search of a treatment target molecule, which is able to regenerate collapsed alveoli, we sought to identify a factor that induces differentiation in human alveolar epithelial stem cells using all-trans retinoic acid (ATRA), whose alveolar repair capacity has been reported in animal experiments. When human alveolar epithelial stem cells were exposed to ATRA at a concentration of 10μM for over seven days, approximately 20% of the cells differentiated into each of the type-I and type-II alveolar epithelial cells that constitute the alveoli. In a microarray analysis, integrin-α1 and integrin-β3 showed the largest variation in the ATRA-treated group compared with the controls. Furthermore, the effect of the induction of differentiation in human alveolar epithelial stem cells using ATRA was suppressed by approximately one-fourth by siRNA treatments with integrin α1 and integrin β3. These results suggested that integrin α1 and β3 are factors responsible for the induction of differentiation in human alveolar epithelial stem cells. We accordingly investigated whether integrin nanoparticles also had a regenerative effect in vivo. Elastase-induced COPD model mouse was produced, and the alveolar repair effect of pulmonary administration using nanoparticles of integrin protein was evaluated by X-ray CT scanning. Improvement in the CT value in comparison with an untreated group indicated that there was an alveolar repair effect. In this study, it was shown that the differentiation-inducing effect on human alveolar epithelial stem cells by ATRA was induced by increased expression of integrin, and that the induced integrin enhanced phosphorylation signaling of AKT, resulting in inducing differentiations. Furthermore, the study demonstrated that lung administration of nanoparticles with increased solubility and stability of integrin

  12. Functional analysis of the cytoplasmic domain of the integrin {alpha}1 subunit in endothelial cells.

    Abair, Tristin D; Bulus, Nada; Borza, Corina; Sundaramoorthy, Munirathinam; Zent, Roy; Pozzi, Ambra


    Integrin alpha1beta1, the major collagen type IV receptor, is expressed by endothelial cells and plays a role in both physiologic and pathologic angiogenesis. Because the molecular mechanisms whereby this collagen IV receptor mediates endothelial cell functions are poorly understood, truncation and point mutants of the integrin alpha1 subunit cytoplasmic tail (amino acids 1137-1151) were generated and expressed into alpha1-null endothelial cells. We show that alpha1-null endothelial cells expressing the alpha1 subunit, which lacks the entire cytoplasmic tail (mutant alpha1-1136) or expresses all the amino acids up to the highly conserved GFFKR motif (mutant alpha1-1143), have a similar phenotype to parental alpha1-null cells. Pro(1144) and Leu(1145) were shown to be necessary for alpha1beta1-mediated endothelial cell proliferation; Lys(1146) for adhesion, migration, and tubulogenesis and Lys(1147) for tubulogenesis. Integrin alpha1beta1-dependent endothelial cell proliferation is primarily mediated by ERK activation, whereas migration and tubulogenesis require both p38 MAPK and PI3K/Akt activation. Thus, distinct amino acids distal to the GFFKR motif of the alpha1 integrin cytoplasmic tail mediate activation of selective downstream signaling pathways and specific endothelial cell functions. PMID:18647959

  13. Integrin activation state determines selectivity for novel recognition sites in fibrillar collagens.

    Siljander, Pia R-M; Hamaia, Samir; Peachey, Anthony R; Slatter, David A; Smethurst, Peter A; Ouwehand, Willem H; Knight, C Graham; Farndale, Richard W


    Only three recognition motifs, GFOGER, GLOGER, and GASGER, all present in type I collagen, have been identified to date for collagen-binding integrins, such as alpha(2)beta(1). Sequence alignment was used to investigate the occurrence of related motifs in other human fibrillar collagens, and located a conserved array of novel GER motifs within their triple helical domains. We compared the integrin binding properties of synthetic triple helical peptides containing examples of such sequences (GLSGER, GMOGER, GAOGER, and GQRGER) or the previously identified motifs. Recombinant inserted (I) domains of integrin subunits alpha(1), alpha(2) and alpha(11) all bound poorly to all motifs other than GFOGER and GLOGER. Similarly, alpha(2)beta(1) -containing resting platelets adhered well only to GFOGER and GLOGER, while ADP-activated platelets, HT1080 cells and two active alpha(2)I domain mutants (E318W, locked open) bound all motifs well, indicating that affinity modulation determines the sequence selectivity of integrins. GxO/SGER peptides inhibited platelet adhesion to collagen monomers with order of potency F >/= L >/= M > A. These results establish GFOGER as a high affinity sequence, which can interact with the alpha(2)I domain in the absence of activation and suggest that integrin reactivity of collagens may be predicted from their GER content. PMID:15345717

  14. Multiple integrin-ligand interactions synergize in shear-resistant platelet adhesion at sites of arterial injury in vivo

    Grüner, Sabine; Prostredna, Miroslava; Schulte, Valerie;


    intravital fluorescence microscopy that platelet adhesion and thrombus growth on the exposed ECM of the injured carotid artery is not significantly altered in alpha2-null mice and even in mice with a Cre/loxP-mediated loss of all beta1 integrins on their platelets. In contrast, inhibition of alphaIIbbeta3...

  15. Low-shear modelled microgravity environment maintains morphology and differentiated functionality of primary porcine hepatocyte cultures.

    Nelson, Leonard J; Walker, Simon W; Hayes, Peter C; Plevris, John N


    Hepatocytes cultured in conventional static culture rapidly lose polarity and differentiated function. This could be explained by gravity-induced sedimentation, which prevents formation of complete three-dimensional (3D) cell-cell/cell-matrix interactions and disrupts integrin-mediated signals (including the most abundant hepatic integrin alpha(5)beta(1)), important for cellular polarity and differentiation. Cell culture in a low fluid shear modelled microgravity (about 10(-2) g) environment promotes spatial colocation/self-aggregation of dissociated cells and induction of 3D differentiated liver morphology. Previously, we demonstrated the utility of a NASA rotary bioreactor in maintaining key metabolic functions and 3D aggregate formation of high-density primary porcine hepatocyte cultures over 21 days. Using serum-free chemically defined medium, without confounding interactions of exogenous bioscaffolding or bioenhancing surface materials, we investigated features of hepatic cellular polarity and differentiated functionality, including expression of hepatic integrin alpha(5), as markers of functional morphology. We report here that in the absence of exogenous biomatrix scaffolding, hepatocytes cultured in serum-free chemically defined medium in a microgravity environment rapidly (microgravity environment may promote tissue-like self-organization of dissociated cells, and offer advantages over spheroids cultured in conventional formats to delineate optimal conditions for enhanced directed tissue self-assembly. PMID:20395654

  16. Elicitor and resistance-inducing activities of beta-1,4 cellodextrins in grapevine, comparison with beta-1,3 glucans and alpha-1,4 oligogalacturonides.

    Aziz, Aziz; Gauthier, Adrien; Bézier, Annie; Poinssot, Benoît; Joubert, Jean-Marie; Pugin, Alain; Heyraud, Alain; Baillieul, Fabienne


    Cellodextrins (CD), water-soluble derivatives of cellulose composed of beta-1,4 glucoside residues, have been shown to induce a variety of defence responses in grapevine (Vitis vinifera L.) cells. The larger oligomers of CD rapidly induced transient generation of H2O2 and elevation in free cytosolic calcium, followed by a differential expression of genes encoding key enzymes of the phenylpropanoid pathway and pathogenesis-related (PR) proteins as well as stimulation of chitinase and beta-1,3 glucanase activities. Most of these defence reactions were also induced by linear beta-1,3 glucans (betaGlu) and alpha-1,4 oligogalacturonides (OGA) of different degree of polymerization (DP), but the intensity of some reactions induced by CD was different when compared with betaGlu and OGA effects. Moreover, desensitization assays using H2O2 production showed that cells treated with CD remained fully responsive to a second application of OGA, suggesting a different mode of perception of these oligosaccharides by grape cells. None of CD, betaGlu, or OGA induced HSR gene expression nor did they induce cell death. In accordance with elicitor activity in grapevine cells, CD-incubated leaves challenged with Botrytis cinerea also resulted in a significant reduction of the disease. Data suggest that CD could operate via other distinct reaction pathways than betaGlu and OGA. They also highlight the requirement of a specific DP for each oligosaccharide to induce the defence response. PMID:17322548

  17. Identification of novel inhibitors of the transforming growth factor beta1 (TGF-beta1) type 1 receptor (ALK5).

    Callahan, James F; Burgess, Joelle L; Fornwald, James A; Gaster, Laramie M; Harling, John D; Harrington, Frank P; Heer, Jag; Kwon, Chet; Lehr, Ruth; Mathur, A; Olson, Barbara A; Weinstock, Joseph; Laping, Nicholas J


    Screening of our internal compound collection for inhibitors of the transforming growth factor beta1 (TGF-beta1) type I receptor (ALK5) identified several hits. Optimization of the dihydropyrroloimidazole hit 2 by introduction of a 2-pyridine and 3,4-methylenedioxyphenyl group gave 7, a selective ALK5 inhibitor. With this information, optimization of the triarylimidazole hit 8 gave the selective inhibitor 14, which inhibits TGF-beta1-induced fibronectin mRNA formation while displaying no measurable cytotoxicity in the 48 h XTT assay. PMID:11855979

  18. Laminin-8 (alpha4beta1gamma1) is synthesized by lymphoid cells, promotes lymphocyte migration and costimulates T cell proliferation.

    Geberhiwot, T; Assefa, D; Kortesmaa, J; Ingerpuu, S; Pedraza, C; Wondimu, Z; Charo, J; Kiessling, R; Virtanen, I; Tryggvason, K; Patarroyo, M


    Laminins are a growing family of large heterotrimeric proteins with cell adhesive and signalling functions. They are major components of basement membranes and are found in many organs, including the vasculature and other compartments of bone marrow, thymus, lymph nodes and spleen. However, expression, recognition and use of laminin isoforms by lymphoid cells are poorly understood. In the present study, lymphoid T cells (Jurkat) were found to synthesize laminin alpha4, beta1 and gamma1 mRNAs and polypeptides and to assemble the chains into laminin-8. Lymphoblastoid B (NAD-20) cells, lymphoid NK (NKL) cells and blood lymphocytes also contained laminin-8 and, after cell permeabilization, practically all blood lymphocytes reacted with mAbs to laminin beta1 and gamma1 chains. Following stimulation, blood lymphocytes secreted laminin-8, and this laminin isoform, but not laminin-10/11(alpha5beta1gamma1/alpha5beta2gamma1), promoted chemokine-induced migration of the cells. In an activation-dependent manner, purified blood CD4 T cells adhered to immobilized laminin-8 and laminin-10/11 by using alpha6beta1 integrin, but minimally to laminin-1 (alpha1beta1gamma1). Accordingly, laminin-8 and laminin-10/11, but not laminin-1, strongly costimulated proliferation of the T cells via the same integrin. Thus, lymphoid cells are able to synthesize and secrete complete laminin molecules. In addition, synthesis of laminin-8 and recognition of laminin-8 and -10/11 by lymphocytes indicate relevance of these laminin isoforms in lymphocyte physiology. PMID:11148143

  19. Factor de crecimiento transformante beta-1: estructura, función y mecanismos de regulación en cáncer Transforming growth factor beta-1: structure, function and regulation mechanisms in cancer

    Oscar Peralta-Zaragoza


    Full Text Available El factor de crecimiento transformante beta-1 (TGF-beta1 es sintetizado por muchas estirpes celulares como linfocitos, macrófagos y células dendríticas, y su expresión regula de manera autócrina o parácrina la diferenciación, proliferación y el estado de activación de éstas y muchas otras células. En general, el TGF-beta1 tiene propiedades pleiotrópicas en el contexto de la respuesta inmune durante el desarrollo de infecciones y procesos neoplásicos; sin embargo, los mecanismos de acción y regulación de la expresión de esta citocina aún no se comprenden del todo. En la presente revisión se describen las propiedades biológicas y los procesos moleculares que regulan la expresión del TGF-beta1, para entender los efectos de esta citocina durante la proliferación y la diferenciación celular. El conocimiento de los mecanismos moleculares de la regulación del TGF-beta1 puede representar una importante estrategia de tratamiento del cáncer. El texto completo en inglés de este artículo está disponible en: growth factor beta-1 (TGF-beta1 is produced by several cell lineages such as lymphocytes, macrophages, and dendritic cells, and its expression serves in both autocrine and paracrine modes to control the differentiation, proliferation, and state of activation of these and other cells. In general, TGF-beta1 has pleiotropic properties on the immune response during the development of infection diseases and cancer; however, the mechanisms of action and regulation of gene expression of this cytokine are poorly understood, In this review, the biological properties and the molecular mechanisms that regulate TGF-beta1 gene expression are described, to understand the role of this cytokine in growth and cell differentiation. The knowledge of molecular mechanisms of gene expression of TGF-beta1 may serve to develop new cancer therapies. The English version of this paper is available at:

  20. Integrin Activation and Viral Infection

    Shan-dian GAO; Jun-zheng DU; Jian-hua ZHOU; Hui-yun CHANG; Qing-ge XIE


    Integrins are members of a ubiquitous membrane receptor family which includes 18 different α subunits and 8 β subunits forming more than 20 α/β heterodimers. Integrins play key functions in vascular endothelial cell and tumour cell adhesion, lymphocyte trafficking, tumor growth and viral infection. Current understanding of the molecular basis of integrins as viral receptors has been achieved through many decades of study into the biology of transmembrane glycoproteins and their interactions with several viruses. This review provides a summary of the current knowledge on the molecular bases of interactions between viruses and integrins, which are of potential practical significance. Inhibition of virus-integrin interactions at the points of virus attachment or entry will provide a novel approach for the therapeutic treatment of viral diseases.

  1. Mouse-Induced Pluripotent Stem Cells Differentiate into Odontoblast-Like Cells with Induction of Altered Adhesive and Migratory Phenotype of Integrin

    Ozeki, Nobuaki; Mogi, Makio; Kawai, Rie; Yamaguchi, Hideyuki; Hiyama, Taiki; Nakata, Kazuhiko; Nakamura, Hiroshi


    Methods for differentiating induced pluripotent stem (iPS) cells into odontoblasts generally require epithelial–mesenchymal interactions. Here, we sought to characterize the cells produced by a ‘hanging drop’ technique for differentiating mouse iPS cells into odontoblast-like cells that requires no such interaction. Cells were cultured by the hanging drop method on a collagen type-I (Col-I) scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4) without an epithelial–mesench...

  2. Functional display of an alpha2 integrin-specific motif (RKK) on the surface of baculovirus particles.

    Riikonen, Reetta; Matilainen, Heli; Rajala, Nina; Pentikainen, Olli; Johnson, Mark; Heino, Jyrki; Oker-Blom, Christian


    The use of baculovirus vectors shows promise as a tool for gene delivery into mammalian cells. These insect viruses have been shown to transduce a variety of mammalian cell lines, and gene transfer has also been demonstrated in vivo. In this study, we generated two recombinant baculovirus vectors displaying an integrin-specific motif, RKK, as a part of two different loops of the green fluorescent protein (GFP) fused with the major envelope protein gp64 of Autographa californica M nucleopolyhedrovirus. By enzyme linked immunosorbent assays, these viruses were shown to bind a peptide representing the receptor binding site of an alpha2 integrin, the alpha2I-domain. However, the interaction was not strong enough to overcome binding of wild type gp64 to the unknown cellular receptor(s) on the surface of alpha2 integrin-expressing cells (CHO-alpha2beta1) or enhance the viral uptake. After treatment of these cells with phospholipase C, internalization of all viruses was blocked or decreased significantly. However, one of the RKK displaying viruses, AcGFP(K)gp64, was still able to internalize into CHO-alpha2beta1 cells, although at a lower level as compared to non-treated cells. This may indicate the possible utilization of a PLC independent alternative route via, in this case, the alpha2beta1 integrin. PMID:16029062

  3. Evaluation of in vivo partial beta 1/beta 2-agonist activity: a dose-ranging study with carteolol.

    Wheeldon, N M; McDevitt, D G; Lipworth, B J


    1. The aims of this study were to investigate the partial agonist profile of carteolol and evaluate methodology for differentiating relative beta 1 and beta 2 partial agonist activity (PAA) in vivo. 2. Eight normal subjects received single oral doses of carteolol 10 mg, 30 mg and 60 mg; nadolol 40 mg; pindolol 30 mg and placebo, given in a single-blind, randomised crossover design. 3. beta 1-PAA was demonstrated with carteolol by dose-related increases in resting heart rate and systolic blood...

  4. Activation of p53 pathway by Nutlin-3a inhibits the expression of the therapeutic target alpha 5 integrin in colon cancer cells

    Janoušková, Hana; Ray, A.M.; Noulet, F.; Lelong-Rebel, I.; Choulier, L.; Schaffner, F.; Lehmann, M.; Martin, S.; Teisinger, Jan; Dontenwill, M.


    Roč. 336, č. 2 (2013), s. 307-318. ISSN 0304-3835 Institutional support: RVO:67985823 Keywords : colon cancer * integrin alpha 5 beta 1 * p53 * Nutlin-3a Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.016, year: 2013

  5. Ubuntu 6.10 Edgy Beta 1发布


    近日,Ubuntu项目发布Ubuntu 6.10 Edgy Eft Beta 1版本,Edgy Eft Beta 1包含新的2.6.17版本内核、Xorg 7.1、GNOME 2.16正式版、新的Firefox浏览器Firefox2.0 Beta2、OpenOffice.org2.0.4RC2版本、聊天软件Gaim的新版本2.0 Beta3.1和新的init系统。

  6. The change of transforming growth factor {beta} 1 (TGF- {beta} 1) expression by melatonin in irradiated lung

    Jang, Seong Soon; Choi, Ihl Bohng [College of Medicine, The Catholic University of Korea, Seoul (Korea, Republic of)


    The changed expressions of TGF- {beta} 1, as a key cytokine in the fibrotic process, due to melatonin with potent antioxidative effects, were investigated in the irradiated lung using fibrosis-sensitive C57BL/6 mice. Female C57BL/6 mice were divided into control irradiation-only, and melatonin (300 mg/kg i.p. 1 hr before irradiation) pretreatment groups. The thoraces of the mice were irradiated with a single dose of 12 Gy. The mRNA expressions of TGF-{beta} 1 in the lung tissue 2 and 4 weeks after irradiation were quantified using semiquantitive RT-PCR, and the cellular origin and expression levels of TGF- {beta} 1 protein were identified using immunohistochemical staining. The relative mRNA expression levels in the irradiation-only and melatonin pretreatment group 2 and 4 weeks after irradiation were 1.92- and 1.80-fold ({rho} = 0.064) and 2.38- and 1.94-fold ({rho} = 0.004) increased, respectively compared to those in the control group. Increased expressions of TGF- {beta} 1 protein were prominently detected in regions of histopathological radiation injury, with alveolar macrophages and septal epithelial cells serving as important sources of TGF- {beta} 1 expression. At 2 and 4 weeks after irradiation, the expression levels of protein were 15.8% vs. 16.9% ({rho} = 0.565) and 36.1% vs. 25.7% ({rho} = 0.009), respectively. The mRNA and protein expressions of TGF- {beta} 1 in the lung tissue following thoracic irradiation with 12 Gy were significantly decreased by melatonin pretreatment at 4 weeks. These results indicate that melatonin may have a possible application as an antifibrotic agent in radiation-induced lung injury.

  7. Different Phenotypes in Human Prostate Cancer: α6 or α3 Integrin in Cell-extracellular Adhesion Sites

    Monika Schmelz


    Full Text Available The distribution of α6/α3 integrin in adhesion complexes at the basal membrane in human normal and cancer prostate glands was analyzed in 135 biopsies from 61 patients. The levels of the polarized α6/α3 integrin expression at the basal membrane of prostate tumor glands were determined by quantitative immunohistochemistry. The α6/α3 integrin expression was compared with Gleason sum score, pathological stage, and preoperative serum prostate-specific antigen (PSA. The associations were assessed by statistical methods. Eighty percent of the tumors expressed the α6 or α3 integrin and 20% was integrin-negative. Gleason sum score, but not serum PSA, was associated with the integrin expression. Low Gleason sum score correlated with increased integrin expression, high Gleason sum score with low and negative integrin expression. Three prostate tumor phenotypes were distinguished based on differential integrin expression. Type I coexpressed both α6 and α3 subunits, type II exclusively expressed a6 integrin, and type III expressed α3 integrin only. Fifteen cases were further examined for the codistribution of vinculin, paxillin, and CD 151 on frozen serial sections using confocal laser scanning microscopy. The α6/α3 integrins, CD151, paxillin, and vinculin were present within normal glands. In prostate carcinoma, α6 integrin was colocalized with CD 151, but not with vinculin or paxillin. In tumor phenotype I, the α6 subunit did not colocalize with the α3 subunit indicating the existence of two different adhesion complexes. Human prostate tumors display on their cell surface the α6β1 and/or α3β1 integrins. Three tumor phenotypes associated with two different adhesion complexes were identified, suggesting a reorganization of cell adhesion structures in prostate cancer.

  8. Integrin Targeted Delivery of Radiotherapeutics

    Zhaofei Liu, Fan Wang, Xiaoyuan Chen


    Full Text Available Targeted radionuclide therapy, which is based on the selective delivery of a sufficient radiation dose to tumors without significantly affecting normal tissues, is a promising therapeutic approach for the treatment of a wide variety of malignancies. Integrins, a family of cell adhesion molecules, play key roles during tumor angiogenesis and metastasis. Among all the integrins, αvβ3 seems to be the most important in the process of tumor angiogenesis. Integrin αvβ3 is highly expressed on activated endothelial cells, new-born vessels as well as some tumor cells, but is not present in resting endothelial cells and most normal organ systems, making it a suitable target for anti-tumor therapy. In this review, we summarize the current development and applications of antibody-, peptide-, and other ligand-based integrin targeted radiotherapeutics for tumor radiation therapy.

  9. The role of integrins in the development and homeostasis of the epidermis and skin appendages.

    Rippa, A L; Vorotelyak, E A; Vasiliev, A V; Terskikh, V V


    Integrins play a critical role in the regulation of adhesion, migration, proliferation, and differentiation of cells. Because of the variety of the functions they play in the cell, they are necessary for the formation and maintenance of tissue structure integrity. The trove of data accumulated by researchers suggests that integrins participate in the morphogenesis of the epidermis and its appendages. The development of mice with tissue-specific integrin genes knockout and determination of the genetic basis for a number of skin diseases in humans showed the significance of integrins in the biology, physiology, and morphogenesis of the epidermis and hair follicles. This review discusses the data on the role of different classes of integrin receptors in the biology of epidermal cells, as well as the development of the epidermis and hair follicles. PMID:24455180

  10. Transforming growth factor-beta1 stimulates the production of insulin-like growth factor-I and insulin-like growth factor-binding protein-3 in human bone marrow stromal osteoblast progenitors

    Kveiborg, Marie; Flyvbjerg, Allan; Eriksen, E F;


    While transforming growth factor-beta1 (TGF-beta1) regulates proliferation and differentiation of human osteoblast precursor cells, the mechanisms underlying these effects are not known. Several hormones and locally acting growth factors regulate osteoblast functions through changes in the insulin......-like growth factors (IGFs) and IGF-binding proteins (IGFBPs). Thus, we studied the effects of TGF-beta1 on IGFs and IGFBPs in human marrow stromal (hMS) osteoblast precursor cells. TGF-beta1 increased the steady-state mRNA level of IGF-I up to 8.5+/-0.6-fold (P...

  11. New insights into structure-function relationship of the DHPR beta1a subunit in skeletal muscle excitation-contraction coupling using zebrafish 'relaxed' as an expression system

    The paralyzed zebrafish strain relaxed carries a null mutation for the skeletal muscle dihydropyridine receptor (DHPR) [beta]1a subunit. The lack of [beta]1a not only impedes functional [alpha]1S membrane expression but also precludes the skeletal muscle-specific ultrastructural arrangement of DHPRs into tetrads opposite ryanodine receptor (RyR1), coherent with the absence of skeletal muscle excitation-contraction (EC) coupling. With the plethora of experimental approaches feasible with zebrafish model organism and importantly with the [beta]1-null mutation having a monogenetic inheritance and because of the survival of the relaxed larvae for some days, we were able to establish the zebrafish relaxed as an expression system. Linking in vitro to in vivo observations, a clear differentiation between the major functional roles of [beta] subunits in EC coupling was feasible. The skeletal muscle [beta]1a subunit was able to restore all parameters of EC coupling upon expression in relaxed myotubes and larvae. Expression of the phylogenetically closest isoform to [beta]1a, the cardiac/neuronal [beta]2a subunit or the most distant neuronal [beta]M from the housefly in relaxed myotubes and larvae was likewise able to fully restore [alpha]1S triad targeting and facilitate charge movement. However, efficient tetrad formation and thus intact DHPR-RyR1 coupling was exclusively promoted by the [beta]1a isoform. Consequently, we postulated a model according to which [beta]1a acts as a unique allosteric modifier of [alpha]1S conformation crucial for skeletal muscle EC coupling. Therefore, unique structural elements in [beta]1a must be present which endow it with this exclusive property. Earlier, a unique hydrophobic heptad repeat motif (LVV) in the [beta]1a C-terminus was postulated by others to be essential for skeletal muscle EC coupling. We wanted to address the question if the proposed [beta]1a heptad repeat motif could be an active element of the DHPR-RyR1 signal transduction

  12. The involvement of Gab1 and PI 3-kinase in β1 integrin signaling in keratinocytes

    The control of the stem cell compartment in epidermis is closely linked to the regulation of keratinocyte proliferation and differentiation. β1 integrins are expressed 2-fold higher by stem cells than transit-amplifying cells. Signaling from these β1 integrins is critical for the regulation of the epidermal stem cell compartment. To clarify the functional relevance of this differential expression of β1 integrins, we established HaCaT cells with high β1integrin expression by repeated flow cytometric sorting of this population from the parental cell line. In these obtained cells expressing β1 integrins by 5-fold, MAPK activation was markedly increased. Regarding the upstream of MAPK, Gab1 phosphorylation was also higher with high β1 integrin expression, while Shc phosphorylation was not altered. In addition, enhanced phosphatidylinositol 3-kinase activation was also observed. These observations suggest that Gab1 and phosphatidylinositol 3-kinase play pivotal roles in the β1 integrin-mediated regulation of the epidermal stem cell compartment

  13. The newcomer in the integrin family: Integrin a9 in biology and cancer

    Høye, Anette Melissa; Couchman, John Robert; Wewer, Ulla M.;


    Integrins are heterodimeric transmembrane receptors regulating cell-cell and cell-extracellular matrix interactions. Of the 24 integrin heterodimers identified in humans, a9ß1 integrin is one of the least studied. a9, together with a4, comprise a more recent evolutionary sub-family of integrins t...

  14. Fibronectin-binding protein acts as Staphylococcus aureus invasin via fibronectin bridging to integrin alpha5beta1

    Sinha, B; François, P P; Nüsse, O; Foti, M; Hartford, O M; Vaudaux, P; Foster, T J; Lew, D P; Herrmann, M; Krause, K H


    The ability of Staphylococcus aureus to invade mammalian cells may explain its capacity to colonize mucosa and to persist in tissues after bacteraemia. To date, the underlying molecular mechanisms of cellular invasion by S. aureus are unknown, despite its high prevalence and difficulties in treatmen

  15. HLA Dr beta 1 alleles in Pakistani patients with rheumatoid arthritis

    Objective: To determine frequencies of HLA DR beta 1 alleles in rheumatoid arthritis in Pakistani patients. Study Design: Cross sectional / analytical study. Place and Duration of Study: Department of Immunology, Armed Forces Institute of Pathology, Rawalpindi in collaboration with Rheumatology departments of Military Hospital, Rawalpindi and Fauji Foundation Hospital, Rawalpindi, from January 2009 to January 2010. Methodology: HLA DR beta 1 genotyping of one hundred Pakistani patients, diagnosed as having RA as per American College of Rheumatology revised criteria 1987, was done. HLA DR beta 1 genotyping was carried out at allele group level (DR beta 1*01-DR beta 1*16) by sequence specific primers in RA patients. Comparison of HLA DR beta 1 allele frequencies between patients and control groups was made using Pearson's chi-square test to find possible association of HLA DR?1 alleles with RA in Pakistani rheumatoid patients. Results: HLA DR beta 1*04 was expressed with significantly increased frequency in patients with rheumatoid arthritis (p <0.05). HLA DR?1*11 was expressed statistically significantly more in control group as compared to rheumatoid patients indicating a possible protective effect. There was no statistically significant difference observed in frequencies of HLA DR beta 1 allele *01, DR beta 1 allele *03, DR beta 1 allele *07, DR beta 1 allele *08, DR beta 1 allele *09, DR beta 1 allele *10, DR beta 1 allele *12, DR beta 1 allele *13, DR beta 1 allele *14, DR?1 allele *15 and DR beta 1 allele *16 between patients and control groups. Conclusion: The identification of susceptible HLA DR beta 1 alleles in Pakistani RA patients may help physicians to make early decisions regarding initiation of early intensive therapy with disease modifying anti rheumatic medicines and biological agents decreasing disability in RA patients. (author)

  16. Compound list: transforming growth factor beta 1 [Open TG-GATEs

    Full Text Available transforming growth factor beta 1 TGFB1 00182 ...

  17. Arginine-Glycine-Aspartate-Binding Integrins as Therapeutic and Diagnostic Targets.

    Sun, Cui-Cui; Qu, Xian-Jun; Gao, Zu-Hua


    Arginine-glycine-aspartate (RGD)-binding integrins, including αvβ1, αvβ3, αvβ5, αvβ6, αvβ8, α5β1, αIIbβ3, and α8β1, recognize the tripeptide motif RGD in their ligands. RGD-binding integrins are involved in various cell functions, including cell proliferation, survival, differentiation, and motility that are critically important to both health and disease. The diagnostic and therapeutic value of some RGD-binding integrin inhibitors are either clinically proven or at different stages of development. In this review, we first summarized the structure and signaling characteristics of RGD-binding integrins. We then discussed the functions of RGD-binding integrins and their association with human disease. Finally, we recapitulated the research efforts and clinical trials of targeting RGD-binding integrins for the diagnosis and treatment of human disease. This comprehensive review of the current advances in RGD-binding integrins could assist scientists and clinicians in gaining a complete understanding of this group of molecules. It can also contribute to the design of new projects to further advance this field of research and to better apply the research results to benefit patients in clinical practice. PMID:24621642

  18. Tumor targeting via integrin ligands



    Full Text Available Selective and targeted delivery of drugs to tumors is a major challenge for an effective cancer therapy and also to overcome the side effects associated with current treatments. Overexpression of various receptors on tumor cells is a characteristic structural and biochemical aspect of tumors and distinguishes them from physiologically normal cells. This abnormal feature is therefore suitable for selectively directing anticancer molecules to tumors by using ligands that can preferentially recognize such receptors. Several subtypes of integrin receptors that are crucial for cell adhesion, cell signaling, cell viability and motility have been shown to have an upregulated expression on cancer cells. Thus, ligands that recognize specific integrin subtypes represent excellent candidates to be conjugated to drugs or drug carrier systems and be targeted to tumors. In this regard, integrins recognizing the RGD cell adhesive sequence have been extensively targeted for tumor specific drug delivery. Here we review key recent examples on the presentation of RGD-based integrin ligands by means of distinct drug delivery systems, and discuss the prospects of such therapies to specifically target tumor cells.

  19. Glomerular injury is exacerbated in diabetic integrin alpha1-null mice.

    Zent, R; Yan, X; Su, Y; Hudson, B G; Borza, D-B; Moeckel, G W; Qi, Z; Sado, Y; Breyer, M D; Voziyan, P; Pozzi, A


    Excessive glomerular collagen IV and reactive oxygen species (ROS) production are key factors in the development of diabetic nephropathy. Integrin alpha1beta1, the major collagen IV receptor, dowregulates collagen IV and ROS production, suggesting this integrin might determine the severity of diabetic nephropathy. To test this possibility, wild-type and integrin alpha1-null mice were rendered diabetic with streptozotocin (STZ) (100 mg/kg single intraperitoneal injection), after which glomerular filtration rate (GFR), glomerular collagen deposition, and glomerular basement membrane (GBM) thickening were evaluated. In addition, ROS and collagen IV production by mesangial cells as well as their proliferation was measured in vitro. Diabetic alpha1-null mice developed worse renal disease than diabetic wild-type mice. A significant increase in GFR was evident in the alpha1-null mice at 6 weeks after the STZ injection; it started to decrease by week 24 and reached levels of non-diabetic mice by week 36. In contrast, GFR only increased in wild-type mice at week 12 and its elevation persisted throughout the study. Diabetic mutant mice also showed increased glomerular deposition of collagen IV and GBM thickening compared to diabetic wild-type mice. Primary alpha1-null mesangial cells exposed to high glucose produced more ROS than wild-type cells, which led to decreased proliferation and increased collagen IV synthesis, thus mimicking the in vivo finding. In conclusion, this study suggests that lack of integrin alpha1beta1 exacerbates the glomerular injury in a mouse model of diabetes by modulating GFR, ROS production, cell proliferation, and collagen deposition. PMID:16775606

  20. Interaction between the insulin-like growth factor family and the integrin receptor family in tissue repair processes. Evidence in a rabbit ear dermal ulcer model.

    Galiano, R D; Zhao, L L; Clemmons, D R; Roth, S. I.; Lin, X.; Mustoe, T. A.


    We have determined previously that IGF-I is dependent on the presence of IGF binding protein-1 (IGFBP-1) to act as a wound healing agent. We sought to determine the mechanism whereby IGFBP-1 is able to enhance IGF-I bioactivity. As IGFBP-1 binds both the alpha5beta1 integrin as well as IGF-I in vitro, we asked which of the following interactions were important: (a) the ability of IGFBP-1 to interact with an integrin receptor, and/or (b) the binding of IGF-I by IGFBP-1. We used an IGF-1 analog...

  1. Current Perspectives on Interferon Beta-1b for the Treatment of Multiple Sclerosis

    Marziniak, Martin; Meuth, Sven


    Interferon (IFN) beta-1b was the first disease-modifying therapy to be approved for the treatment of multiple sclerosis (MS), and over 21 years of follow-up data demonstrate its efficacy and long-term safety profile. Following recent regulatory approvals in the USA and European Union, IFN beta-1b is now one of the seven disease-modifying therapies [intramuscular IFN beta-1a; subcutaneous (SC) IFN beta-1a; IFN beta-1b SC; glatiramer acetate SC; oral dimethyl fumarate; oral teriflunomide; and i...

  2. Integrin Expression Regulates Neuroblastoma Attachment and Migration

    Amy Meyer


    Full Text Available Neuroblastoma (NBL is the most common malignant disease of infancy, and children with bone metastasis have a mortality rate greater than 90%. Two major classes of proteins, integrins and growth factors, regulate the metastatic process. We have previously shown that tumorigenic NBL cells express higher levels of the type I insulin-like growth factor receptor (IGF-IR and that β1 integrin expression is inversely proportional to tumorigenic potential in NBL. In the current study, we analyze the effect of β1 integrin and IGF-IR on NBL cell attachment and migration. Nontumorigenic S-cells express high levels of β1 integrin, whereas tumorigenic N-cells express little β1 integrin. Alterations in (3, integrin are due to regulation at the protein level, as translation is decreased in N-type cells. Moreover, inhibition of protein synthesis shows that β1 integrin is degraded more slowly in S-type cells (SHEP than in N-type cells (SH-SY5Y and IMR32. Inhibition of α5β1 integrin prevents SHEP (but not SH-SY5Y or IMR32 cell attachment to fibronectin and increases SHEP cell migration. Increases in IGF-IR decrease β1 integrin expression, and enhance SHEP cell migration, potentially through increased expression of αvβ3. These data suggest that specific classes of integrins in concert with IGF-IR regulate NBL attachment and migration.

  3. Anti-Integrin Therapy for Multiple Sclerosis

    Eiji Kawamoto


    Full Text Available Integrins are the foremost family of cell adhesion molecules that regulate immune cell trafficking in health and diseases. Integrin alpha4 mediates organ-specific migration of immune cells to the inflamed brain, thereby playing the critical role in the pathogenesis of multiple sclerosis. Anti-alpha4 integrin therapy aiming to block infiltration of autoreactive lymphocytes to the inflamed brain has been validated in several clinical trials for the treatment of multiple sclerosis. This paper provides readers with an overview of the molecular and structural bases of integrin activation as well as rationale for using anti-alpha4 integrin therapy for multiple sclerosis and then chronicles the rise and fall of this treatment strategy using natalizumab, a humanized anti-alpha4 integrin.

  4. Anti-Integrin Therapy for Multiple Sclerosis

    Motomu Shimaoka; Hiroshi Imai; Takayuki Okamoto; Susumu Nakahashi; Eiji Kawamoto


    Integrins are the foremost family of cell adhesion molecules that regulate immune cell trafficking in health and diseases. Integrin alpha4 mediates organ-specific migration of immune cells to the inflamed brain, thereby playing the critical role in the pathogenesis of multiple sclerosis. Anti-alpha4 integrin therapy aiming to block infiltration of autoreactive lymphocytes to the inflamed brain has been validated in several clinical trials for the treatment of multiple sclerosis. This paper pr...

  5. Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia

    We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions

  6. The Effect of Stromal Integrin β3-Deficiency on Two Different Tumors in Mice

    Inga Reigstad


    Full Text Available There is an increasing focus on the tumor microenvironment in carcinogenesis. Integrins are important receptors and adhesion molecules in this environment and have been shown to be involved in cell adhesion, proliferation, differentiation and migration. The present study aimed to evaluate the effect of stromal integrin β3-deficiency on tumor growth, angiogenesis, interstitial fluid pressure (PIF, fibrosis and metastasis in a murine breast cancer (4T1 and a prostate tumor (RM11 model. We showed that stromal integrin β3-deficiency led to an elevation in PIF that correlated to a shift towards thicker collagen fibrils in the 4T1 mammary tumor. In the RM11 prostate carcinoma model there was no effect of integrin β3-deficiency on PIF and collagen fibril thickness. These findings support the notion that changes in the collagen scaffold influence PIF, and also indicate that there must be important crosstalk between the stroma and tumor cells, in a tumor cell line specific manner. Furthermore, stromal integrin β3-deficiency had no effect on tumor growth or angiogenesis in both tumor models and no effect on lung metastasis in the 4T1 mammary tumor model. In conclusion, the stromal β3 integrin influence PIF, possibly via its effect on the structure of the collagen network, in a tumor cell line dependent manner.

  7. Bilinexin, a snake C-type lectin from Agkistrodon bilineatus venom agglutinates platelets via GPIb and alpha2beta1.

    Du, X Y; Navdaev, A; Clemetson, J M; Magnenat, E; Wells, T N; Clemetson, K J


    A new snake protein, named bilinexin, has been purified from Agkistrodon bilineatus venom by ion-exchange chromatography and gel filtration chromatography. Under non-reducing conditions it has a mass of 110 kDa protein on SDS-PAGE. On reduction, it can be separated into five subunits with masses in the range 13-25 kDa. The N-terminal sequences of these subunits are very similar to those of convulxin or the alboaggregins, identifying bilinexin as a new member of the snake C-type lectin family, unusual in having multiple subunits. Bilinexin agglutinates fixed platelets. washed platelets and platelet rich plasma (PRP) without obvious activation (shape change) as confirmed by light microscope examination. Both inhibitory and binding studies indicate that antibodies against alpha2beta1 inhibit not only platelet agglutination induced by bilinexin, but also bilinexin binding to platelets. VM16d, a monoclonal anti-GPIbalpha antibody, completely inhibits platelet agglutination induced by bilinexin, and polyclonal antibodies against GPIbalpha prevent its binding to platelets. However, neither convulxin, polyclonal anti-GPVI antibodies, nor GPIIb/IIIa inhibitors affect its binding to and agglutination of platelets. Bilinexin neither activates GPIIb/IIIa integrin on platelets nor induces tyrosine phosphorylation of platelet proteins, nor increases intracellular Ca2+ in platelets. Like alboaggregin B, bilinexin agglutinates platelets, which makes it a good tool to investigate the differences in mechanism between snake C-type lectins causing platelet agglutination and those that induce full activation. PMID:11816718

  8. In situ validation of VEGFR-2 and α v ß 3 integrin as targets for breast lesion characterization.

    Ehling, Josef; Misiewicz, Matthias; von Stillfried, Saskia; Möckel, Diana; Bzyl, Jessica; Pochon, Sibylle; Lederle, Wiltrud; Knuechel, Ruth; Lammers, Twan; Palmowski, Moritz; Kiessling, Fabian


    Vascular endothelial growth factor receptor 2 (VEGFR-2) and α v ß 3 integrin are the most frequently addressed targets in molecular imaging of tumor angiogenesis. In preclinical studies, molecular imaging of angiogenesis has shown potential to detect and differentiate benign and malignant lesions of the breast. Thus, in this retrospective clinical study employing patient tissues, the diagnostic value of VEGFR-2, α v ß 3 integrin and vascular area fraction for the diagnosis and differentiation of breast neoplasia was evaluated. To this end, tissue sections of breast cancer (n = 40), pre-invasive ductal carcinoma in situ (DCIS; n = 8), fibroadenoma (n = 40), radial scar (n = 6) and normal breast tissue (n = 40) were used to quantify (1) endothelial VEGFR-2, (2) endothelial α v ß 3 integrin and (3) total α v ß 3 integrin expression, as well as (4) the vascular area fraction. Sensitivity and specificity to differentiate benign from malignant lesions were calculated for each marker by receiver operating characteristics (ROC) analyses. Whereas vessel density, as commonly used, did not significantly differ between benign and malignant lesions (AUROC: 0.54), VEGFR-2 and α v ß 3 integrin levels were gradually up-regulated in carcinoma versus fibroadenoma versus healthy tissue. The highest diagnostic accuracy for differentiating carcinoma from fibroadenoma was found for total α v ß 3 integrin expression (AUROC: 0.76), followed by VEGFR-2 (AUROC: 0.71) and endothelial α v ß 3 integrin expression (AUROC: 0.68). In conclusion, total α v ß 3 integrin expression is the best discriminator between breast cancer, fibroadenoma and normal breast tissue. With respect to vascular targeting and molecular imaging of angiogenesis, endothelial VEGFR-2 appeared to be slightly superior to endothelial α v ß 3 for differentiating benign from cancerous lesions. PMID:26902100

  9. Localization of insulin-like growth factor (IGFBP)-3 in cultured porcine embryonic myogenic cells before and after TGF-beta1 treatment.

    Xi, G; Hathaway, M R; White, M E; Dayton, W R


    Insulin-like growth factor binding protein (IGFBP)-3 binds IGFs with high affinity and affects their biological activity. IGFBP-3 that is not bound to IGF also affects cells via mechanisms involving binding to specific cell surface receptors and/or transport into the cell. IGFBP-3 is produced by porcine embryonic myogenic cell (PEMC) cultures. Additionally, IGFBP-3 facilitates the proliferation-suppressing actions of TGF-beta(1) and myostatin in PEMC cultures via mechanisms that do not involve IGF binding. Moreover, these mechanisms do not involve preventing myostatin or TGF-beta(1)-induced increases in phosphosmad2 or phosphosmad3 level. Consequently, the mechanism(s) by which IGFBP-3 facilitates the proliferation-suppressing actions of TGF-beta(1) and myostatin in PEMC is unclear. Since IGFBP-3 reportedly interacts with nuclear proteins that regulate transcription, TGF-beta(1) or myostatin-induced translocation of IGFBP-3 into the nucleus may facilitate the proliferation-suppressing actions of these cytokines. Here, we show that IGFBP-3 is localized in cells containing the muscle specific protein desmin, thus establishing the presence of this IGFBP in myogenic cells. IGFBP-3 is present in the cytoplasm of all myogenic cells and approximately 50% of the nuclei of proliferating PEMC. IGFBP-3 is also detectable in fused myotubes. IGFBP-3 suppresses IGF-I-stimulated differentiation of PEMC but has no affect on Long-R3-IGF-I-stimulated differentiation of PEMC. Treatment of PEMC for 24h with TGF-beta(1) (20 ng/ml) results in a 78% (p<0.01) increase in the number of nuclei that contain detectable IGFBP-3. These results suggest that translocation of IGFBP-3 into the nucleus of PEMC could play a role in mediating the proliferation-suppressing action of TGF-beta(1). PMID:17049199

  10. Extracellular matrix stiffness dictates Wnt expression through integrin pathway.

    Du, Jing; Zu, Yan; Li, Jing; Du, Shuyuan; Xu, Yipu; Zhang, Lang; Jiang, Li; Wang, Zhao; Chien, Shu; Yang, Chun


    It is well established that extracellular matrix (ECM) stiffness plays a significant role in regulating the phenotypes and behaviors of many cell types. However, the mechanism underlying the sensing of mechanical cues and subsequent elasticity-triggered pathways remains largely unknown. We observed that stiff ECM significantly enhanced the expression level of several members of the Wnt/β-catenin pathway in both bone marrow mesenchymal stem cells and primary chondrocytes. The activation of β-catenin by stiff ECM is not dependent on Wnt signals but is elevated by the activation of integrin/ focal adhesion kinase (FAK) pathway. The accumulated β-catenin then bound to the wnt1 promoter region to up-regulate the gene transcription, thus constituting a positive feedback of the Wnt/β-catenin pathway. With the amplifying effect of positive feedback, this integrin-activated β-catenin/Wnt pathway plays significant roles in mediating the enhancement of Wnt signal on stiff ECM and contributes to the regulation of mesenchymal stem cell differentiation and primary chondrocyte phenotype maintenance. The present integrin-regulated Wnt1 expression and signaling contributes to the understanding of the molecular mechanisms underlying the regulation of cell behaviors by ECM elasticity. PMID:26854061

  11. Determination of transforming growth factor-beta 1 (TGF-beta 1) and insulin-like growth factor (IGF-1) in bovine colostrum samples.

    Ginjala, V; Pakkanen, R


    The major growth factors in bovine colostrum are transforming growth factor-beta s (TGF-beta 1 and TGF-beta 2) and insulin-like growth factors (IGF-1 and IGF-2). Recently, TGF-beta 2 content of bovine colostrum was measured using a TGF-beta 2 specific ELISA (1) and now we have validated ELISAs for for bovine TGF-beta 1 and IGF-1. The concentrations of IGF-1 and TGF-beta 1 in the first milking after calving were 248-1850 ng/ml and 12.4-42.6 ng/ml, respectively, and they declined in correlation with total protein concentration to 27.0-101 ng/ml (IGF-1) and 0.80-3.49 ng/ml(TGF-beta 1) by the fifth milkings. The amount of TGF-beta 1 was on average 5.3 +/- 1.4% of that of TGF-beta 2 and there is a high correlation (r = 0.966) between the concentrations of these growth factors in the same samples. No free TGF-beta 1 form of could be detected. PMID:9682131

  12. Molecular cloning and characterisation of a pattern recognition molecule, lipopolysaccharide- and beta-1,3-glucan binding protein (LGBP) from the white shrimp Litopenaeus vannamei.

    Cheng, Winton; Liu, Chun-Hung; Tsai, Chiung-Hui; Chen, Jiann-Chu


    A lipopolysaccharide- and beta-1,3-glucan binding protein (LGBP) cDNA was cloned from the haemocyte and hepatopancreas of white shrimp Litopenaeus vannamei using oligonucleotide primers and RT-PCR. Both 3'- and 5'-regions were isolated by rapid amplification of cDNA end RACE method. Analysis of nucleotide sequence revealed that the cDNA clone has an open reading frame of 1101 bp encoding a protein of 367 amino acids including a 17 amino acid signal peptide. The calculated molecular mass of the mature proteins (350 amino acids) is 39.92 kDa with an estimated pI of 4.37. Two putative integrin binding motifs (cell adhesion site), RGD (Arg-Gly-Asp) and a potential recognition motif for beta- (1-->3) linkage of polysaccharides were observed in the LGBP. Sequence comparison showed that LGBP deduced amino acid of L. vannamei has an overall similarity of 95%, 92% and 61% to that of blue shrimp Litopenaeus stylirostris LGBP, tiger shrimp Penaeus monodon BGBP and crayfish Pacifastacus leniusculus LGBP, respectively. Quantitative real-time RT-PCR analysis showed that LGBP transcript in haemocyte of L. vannamei increased in 3- and 6-h post Vibrio alginolyticus injection. PMID:15561560

  13. Molecular cloning and characterisation of a pattern recognition protein, lipopolysaccharide and beta-1,3-glucan binding protein (LGBP) from Chinese shrimp Fenneropenaeus chinensis.

    Liu, Fengsong; Li, Fuhua; Dong, Bo; Wang, Xiaomei; Xiang, Jianhai


    A pattern recognition protein (PRP), lipopolysaccharide and beta-1,3-glucan binding protein (LGBP) cDNA was cloned from the haemocyte of Chinese shrimp Fenneropenaeus chinensis by the techniques of homology cloning and RACE. Analysis of nucleotide sequence revealed that the full-length cDNA of 1,275 bp has an open reading frame of 1,098 bp encoding a protein of 366 amino acids including a 17 amino acid signal peptide. Sequence comparison of the deduced amino acid sequence of F. chinensis LGBP showed a high identity of 94%, 90%, 87%, 72% and 63% with Penaeus monodon BGBP, Litopenaeus stylirostris LGBP, Marsupenaeu japonicus BGBP, Homarus gammarus BGBP and Pacifastacus leniusculus LGBP, respectively. The calculated molecular mass of the mature protein is 39,857 Da with a deduced pI of 4.39. Two putative integrin binding motifs, RGD (Arg-Gly-Asp) and a potential recognition motif for beta-1,3-linkage of polysaccharides were observed in LGBP sequence. RT-PCR analysis showed that LGBP gene expresses in haemocyte and hepatopancreas only, but not in other tissues. Capillary electrophoresis RT-PCR method was used to quantify the variation of mRNA transcription level during artificial infection with heat-killed Vibrio anguillarum and Staphylococcus aureusin. A significant enhancement of LGBP transcription was appeared at 6 h post-injection in response to bacterial infection. These results have provided useful information to understand the function of LGBP in shrimp. PMID:18163220

  14. Integrin αvβ3 expression in tongue squamous carcinoma cells Cal27 confers anticancer drug resistance through loss of pSrc(Y418).

    Stojanović, Nikolina; Brozovic, Anamaria; Majhen, Dragomira; Bosnar, Maja Herak; Fritz, Gerhard; Osmak, Maja; Ambriović-Ristov, Andreja


    Integrins play key roles in the regulation of tumor cell adhesion, migration, invasion and sensitivity to anticancer drugs. In the present study we investigate the mechanism of resistance of tongue squamous carcinoma cells Cal27 with de novo integrin αvβ3 expression to anticancer drugs. Cal27-derived cell clones, obtained by transfection of plasmid containing integrin subunit β3 cDNA, as compared to control cells demonstrate: expression of integrin αvβ3; increased expression of integrin αvβ5; increased adhesion to fibronectin and vitronectin; resistance to cisplatin, mitomycin C, doxorubicin and 5-fluorouracil; increased migration and invasion, increased amount of integrin-linked kinase (ILK) and decreased amounts of non-receptor tyrosine kinase (Src) and pSrc(Y418). Knockdown of ILK and integrin β5 in cells expressing integrin αvβ3 ruled out their involvement in drug resistance. Opposite, Src knockdown in Cal27 cells which led to a reduction in pSrc(Y418), as well as treatment with the pSrc(Y418) inhibitors dasatinib and PP2, conferred resistance to all four anticancer drugs, indicating that the loss of pSrc(Y418) is responsible for the observed effect. We identified differential integrin signaling between Cal27 and integrin αvβ3-expressing cells. In Cal27 cells integrin αv heterodimers signal through pSrc(Y418) while this is not the case in integrin αvβ3-expressing cells. Finally, we show that dasatinib counteracts the effect of cisplatin in two additional head and neck squamous cell carcinoma (HNSCC) cell lines Cal33 and Detroit562. Our results suggest that pSrc(Y418) inhibitors, potential drugs for cancer therapy, may reduce therapeutic efficacy if combined with chemotherapeutics, and might not be recommended for HNSCC treatment. PMID:27108184

  15. In vivo evaluation of expression of TGF{beta}1 in the irradiated heart; Expressao da proteina TGF{beta}1 em coracao irradiado in vivo

    Affonso Junior, Renato Jose [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina. Dept. Diagnostico por Imagem; Oshima, Celina Tizuko Fujiyama; Silva, Maria Regina Regis [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina. Setor de Anatomia Patologica; Kimura, Edna Teruko [Sao Paulo Univ., SP (Brazil). Inst. de Ciencias Biomedicas. Dept. de Histologia; Egami, Mizue Imoto [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina. Dept. de Morfologia; Segreto, Roberto Araujo; Segreto, Helena Regina Comodo [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Escola Paulista de Medicina. Setor de Radioterapia]. E-mail:


    The objectives of this study were to assess the latent and active TGF{beta}1 localization in the heart, to evaluate whether or not radiation induces latent TGF{beta}1 activation, and to study the distribution of collagen fibers in the irradiated heart. Thirty-two C 57 BL mice were randomly assigned in two groups: GI (non irradiated animals) and GII (irradiated animals). The mice from G II received a single whole-body radiation dose of 7 Gy, using a {sup 60}Co source at a dose rate of 0.97 Gy/min. The animals were sacrificed by cervical dislocation at 1, 14, 30 and 90 days after irradiation. The irradiated hearts showed: nuclear changes and muscle cells with decreased striations; significant increase in the collagen deposition 90 days after irradiation; latent TGF{beta}1 activation in the cardio myocytes and connective tissue cells after irradiation. Our results show the importance of TGF{beta}1 protein in the process of radiation-induced heart fibrosis and suggest that cardio myocytes and connective cells may play a role in this mechanism acting as cellular sources of active TGF{beta}1. (author)

  16. Potential targets of transforming growth factor-beta1 during inhibition of oocyte maturation in zebrafish

    Clelland Eric


    Full Text Available Abstract Background TGF-beta is a multifunctional growth factor involved in regulating a variety of cellular activities. Unlike mammals, the function of TGF-beta in the reproduction of lower vertebrates, such as fish, is not clear. Recently, we showed that TGF-beta1 inhibits gonadotropin- and 17alpha, 20beta-dihydroxyprogesterone (DHP-induced maturation in zebrafish. The aim of the present study was to investigate the mechanisms underlying this action. Method To determine if the effect of TGF-beta1 on oocyte maturation involves transcription and/or translation, ovarian follicles were pre-treated with actinomycin D, a blocker of transcription, and cyclohexamide, an inhibitor of translation, and incubated with hCG or DHP, either alone or in combination with TGF-beta1 and oocyte maturation scored. To determine the effect of TGF-beta1 on mRNA levels of several key effectors of oocyte maturation, three sets of experiments were performed. First, follicles were treated with control medium or TGF-beta1 for 2, 6, 12, and 24 h. Second, follicles were treated with different concentrations of TGF-beta1 (0 to 10 ng/ml for 18 h. Third, follicles were incubated with hCG in the absence or presence of TGF-beta1 for 18 h. At the end of each experiment, total RNA was extracted and reverse transcribed. PCR using primers specific for 20beta-hydroxysteroid dehydrogenase (20beta-HSD which is involved in DHP production, follicle stimulating hormone receptor (FSHR, luteinizing hormone receptor (LHR, the two forms of membrane progestin receptor: mPR-alpha and mPR-beta, as well as GAPDH (control, were performed. Results Treatment with actinomycin D, a blocker of transcription, reduced the inhibitory effect of TGF-beta1 on DHP-induced oocyte maturation, indicating that the inhibitory action of TGF-beta1 is in part due to regulation of gene transcription. Treatment with TGF-beta1 caused a dose and time-dependent decrease in mRNA levels of 20beta-HSD, LHR and mPR-beta in

  17. Curcumin inhibits cellular condensation and alters microfilament organization during chondrogenic differentiation of limb bud mesenchymal cells.

    Kim, Dong Kyun; Kim, Song Ja; Kang, Shin Sung; Jin, Eun Jung


    Curcumin is a well known natural polyphenol product isolated from the rhizome of the plant Curcuma longa, anti-inflammatory agent for arthritis by inhibiting synthesis of inflammatory prostaglandins. However, the mechanisms by which curcumin regulates the functions of chondroprogenitor, such as proliferation, precartilage condensation, cytoskeletal organization or overall chondrogenic behavior, are largely unknown. In the present report, we investigated the effects and signaling mechanism of curcumin on the regulation of chondrogenesis. Treating chick limb bud mesenchymal cells with curcumin suppressed chondrogenesis by stimulating apoptotic cell death. It also inhibited reorganization of the actin cytoskeleton into a cortical pattern concomitant with rounding of chondrogenic competent cells and down-regulation of integrin beta1 and focal adhesion kinase (FAK) phosphorylation. Curcumin suppressed the phosphorylation of Akt leading to Akt inactivation. Activation of Akt by introducing a myristoylated, constitutively active form of Akt reversed the inhibitory actions of curcumin during chondrogenesis. In summary, for the first time, we describe biological properties of curcumin during chondrogenic differentiation of chick limb bud mesenchymal cells. Curcumin suppressed chondrogenesis by stimulating apoptotic cell death and down-regulating integrin-mediated reorganization of actin cytoskeleton via modulation of Akt signaling. PMID:19478554

  18. Interaction between fibronectin and β1 integrin is essential for tooth development.

    Kan Saito

    Full Text Available The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation.

  19. Inhibition of vimentin or B1 integrin reverts morphology of prostate tumor cells grown in laminin-rich extracellular matrix gels and reduces tumor growth in vivo

    Zhang, Xueping; Fournier, Marcia V; Ware, Joy L; Bissell, Mina J; Yacoub, Adly; Zehner, Zendra E


    Prostate epithelial cells grown embedded in laminin-rich extracellular matrix (lrECM) undergo morphologic changes that closely resemble their architecture in vivo. In this study, growth characteristics of three human prostate epithelial sublines derived from the same cellular lineage, but displaying different tumorigenic and metastatic properties in vivo, were assessed in three-dimensional lrECM gels. M12, a highly tumorigenic and metastatic subline, was derived from the immortalized, prostate epithelial P69 cell line by selection in athymic, nude mice and found to contain a deletion of 19p-q13.1. The stable reintroduction of an intact human chromosome 19 into M12 resulted in a poorly tumorigenic subline, designated F6. When embedded in lrECM gels, the parental, nontumorigenic P69 line produced acini with clearly defined lumena. Immunostaining with antibodies to {beta}-catenin, E-cadherin, or {alpha}6 and {beta}1 integrins showed polarization typical of glandular epithelium. In contrast, the metastatic M12 subline produced highly disorganized cells with no evidence of polarization. The F6 subline reverted to acini-like structures exhibiting basal polarity marked with integrins. Reducing either vimentin levels via small interfering RNA interference or the expression of {alpha}6 and {beta}1 integrins by the addition of blocking antibodies, reorganized the M12 subline into forming polarized acini. The loss of vimentin significantly reduced M12-Vim tumor growth when assessed by s.c. injection in athymic mice. Thus, tumorigenicity in vivo correlated with disorganized growth in three-dimensional lrECM gels. These studies suggest that the levels of vimentin and {beta}1 integrin play a key role in the homeostasis of the normal acinus in prostate and that their dysregulation may lead to tumorigenesis. [Mol Cancer Ther 2009;8(3):499-508].

  20. Endoglin negatively regulates transforming growth factor beta1-induced profibrotic responses in intestinal fibroblasts.

    Burke, J P


    BACKGROUND: Fibroblasts isolated from strictures in Crohn\\'s disease (CD) exhibit reduced responsiveness to stimulation with transforming growth factor (TGF) beta1. TGF-beta1, acting through the smad pathway, is critical to fibroblast-mediated intestinal fibrosis. The membrane glycoprotein, endoglin, is a negative regulator of TGF-beta1. METHODS: Intestinal fibroblasts were cultured from seromuscular biopsies of patients undergoing intestinal resection for CD strictures or from control patients. Endoglin expression was assessed using confocal microscopy, flow cytometry and western blot. The effect of small interfering (si) RNA-mediated knockdown and plasmid-mediated overexpression of endoglin on fibroblast responsiveness to TGF-beta1 was assessed by examining smad phosphorylation, smad binding element (SBE) promoter activity, connective tissue growth factor (CTGF) expression and ability to contract collagen. RESULTS: Crohn\\'s stricture fibroblasts expressed increased constitutive cell-surface and whole-cell endoglin relative to control cells. Endoglin co-localized with filamentous actin. Fibroblasts treated with siRNA directed against endoglin exhibited enhanced TGF-beta1-mediated smad-3 phosphorylation, and collagen contraction. Cells transfected with an endoglin plasmid did not respond to TGF-beta1 by exhibiting SBE promoter activity or producing CTGF. CONCLUSION: Fibroblasts from strictures in CD express increased constitutive endoglin. Endoglin is a negative regulator of TGF-beta1 signalling in the intestinal fibroblast, modulating smad-3 phosphorylation, SBE promoter activity, CTGF production and collagen contraction.

  1. Two pine endo-beta-1,4-glucanases are associated with rapidly growing reproductive structures.

    Loopstra, C A; Mouradov, A; Vivian-Smith, A; Glassick, T V; Gale, B V; Southerton, S G; Marshall, H; Teasdale, R D


    Two cDNA clones encoding endo-beta-1,4-glucanases (EGases) were isolated from a radiata pine (Pinus radiata) cDNA library prepared from immature female strobili. The cDNAs PrCel1 (inus adiata cellulase ) and PrCel2 encode proteins 509 and 515 amino acids in length, respectively, including putative signal peptides. Both proteins contain domains conserved in plant and bacterial EGases. The proteins PRCEL1 and PRCEL2 showed strong similarity to each other (76% amino acid identity), and higher similarity to TPP18 (73 and 67%, respectively), an EGase cloned from tomato (Lycopersicon esculentum) pistils, than to any other reported EGases. Northern-blot analyses indicated that both genes displayed a similar pattern of expression. The only significant difference was in the level of expression. In situ hybridizations were used to demonstrate that, within differentiating pine reproductive structures, PrCel1 expression was greatest in microsporangia in pollen strobili and near the developing ovule in the seed strobili. Expression was also found in vegetative tissues, especially in regions experiencing cell elongation, such as the elongating region of root tips. Both proteins have an ability to degrade carboxymethylcellulose in vitro. Genomic-blot analysis indicated the presence of a family of EGase genes in the radiata pine genome, and that PrCel1 and PrCel2 are transcribed from distinct one-copy genes. PMID:9501128

  2. Tissue inhibitor of metalloproteinase-2 (TIMP-2) regulates myogenesis and β1 integrin expression in vitro

    Myogenesis in vitro involves myoblast cell cycle arrest, migration, and fusion to form multinucleated myotubes. Extracellular matrix (ECM) integrity during these processes is maintained by the opposing actions of matrix metalloproteinase (MMP) proteases and their inhibitors, the tissue inhibitor of metalloproteinases (TIMPs). Here, we report that TIMP-2, MMP-2, and MT1-MMP are differentially expressed during mouse myoblast differentiation in vitro. A specific role for TIMP-2 in myogenesis is demonstrated by altered TIMP-2-/- myotube formation. When differentiated in horse serum-containing medium, TIMP-2-/- myotubes are larger than wild-type myotubes. In contrast, when serum-free medium is used, TIMP-2-/- myotubes are smaller than wild-type myotubes. Regardless of culture condition, myotube size is directly correlated with MMP activity and inversely correlated with β1 integrin expression. Treatment with recombinant TIMP-2 rescues reduced TIMP-2-/- myotube size and induces increased MMP-9 activation and decreased β1 integrin expression. Treatment with either MMP-2 or MMP-9 similarly rescues reduced myotube size, but has no effect on β1 integrin expression. These data suggest a specific regulatory relationship between TIMP-2 and β1 integrin during myogenesis. Elucidating the role of TIMP-2 in myogenesis in vitro may lead to new therapeutic options for the use of TIMP-2 in myopathies and muscular dystrophies in vivo

  3. Isolation of extracellular 28- and 42-kilodalton beta-1,3-glucanases and comparison of three beta-1,3-glucanases produced by Bacillus circulans IAM1165.

    Aono, R; Hammura, M; Yamamoto, M.; Asano, T.


    Bacillus circulans IAM1165 produces three major extracellular beta-1,3-glucanases (molecular masses, 28, 42, and 91 kDa) during the stationary phase of growth. The 28- and 42-kDa enzymes were purified to homogeneity from the culture supernatant in this study. The properties of these two enzymes were examined, together with those of the 91-kDa enzyme previously isolated. The enzymatic properties of the 28- and 42-kDa beta-1,3-glucanases closely resemble each other. The enzymes belong to a cate...

  4. Effects of beta-1,3-glucan from Septoria tritici on structural defence responses in wheat

    Shetty, N.P.; Jensen, J.D.; Knudsen, A.;


    -1,3-glucanase and chitinase transcripts followed by a subsequent reduction in level. Resistance was also associated with high activity of beta-1,3-glucanase, especially in the apoplastic fluid, in accordance with the biotrophic/endophytic lifestyle of the pathogen in the apoplastic spaces, thus...... of callose. Collectively, these data indicate that resistance is dependent on a fast, initial recognition of the pathogen, probably due to beta-1,3-glucan in the fungal cell walls, and this results in the accumulation of beta-1,3-glucanase and structural defence responses, which may directly inhibit...... the pathogen and protect the host against fungal enzymes and toxins....

  5. Factor de crecimiento transformante beta-1: estructura, función y mecanismos de regulación en cáncer

    Oscar Peralta Zaragoza; A. Lagunas Martínez; Vicente Madrid Marina


    Transforming growth factor beta-1 (TGF-b1) is produced by several cell lineages such as lymphocytes, macrophages, and dendritic cells, and its expression serves in both autocrine and paracrine modes to control the differentiation, proliferation, and state of activation of these and other cells. In general, TGF-b1 has pleiotropic properties on the immune response during the development of infection diseases and cancer; however, the mechanisms of action and regulation of gene expression of this...

  6. The antifibrotic effects of TGF-{beta}1 siRNA on hepatic fibrosis in rats

    Lang, Qing; Liu, Qi [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China); Xu, Ning [The Second Hospital of YuLin, Shanxi Province (China); Qian, Ke-Li; Qi, Jing-Hu; Sun, Yin-Chun; Xiao, Lang [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China); Shi, Xiao-Feng, E-mail: [Key Laboratory of Molecular Biology for Infectious Diseases, Ministry of Education, Instituted for Virus Hepatitis and Department of Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing (China)


    Highlights: {yields} We constructed CCL4 induced liver fibrosis model successfully. {yields} We proofed that the TGF-{beta}1 siRNA had a definite therapy effect to CCL4 induced liver fibrosis. {yields} The therapy effect of TGF-{beta}1 siRNA had dose-dependent. -- Abstract: Background/aims: Hepatic fibrosis results from the excessive secretion of matrix proteins by hepatic stellate cells (HSCs), which proliferate during fibrotic liver injury. Transforming growth factor (TGF)-{beta}1 is the dominant stimulus for extracellular matrix (ECM) production by stellate cells. Our study was designed to investigate the antifibrotic effects of using short interference RNA (siRNA) to target TGF-{beta}1 in hepatic fibrosis and its mechanism in rats exposed to a high-fat diet and carbon tetrachloride (CCL4). Methods: A total of 40 healthy, male SD (Sprague-Dawley) rats were randomly divided into five even groups containing of eight rats each: normal group, model group, TGF-{beta}1 siRNA 0.125 mg/kg treatment group, TGF-{beta}1 siRNA 0.25 mg/kg treatment group and TGF-{beta}1 siRNA negative control group (0.25 mg/kg). CCL4 and a high-fat diet were used for 8 weeks to induce hepatic fibrosis. All the rats were then sacrificed to collect liver tissue samples. A portion of the liver samples were soaked in formalin for Hematoxylin-Eosin staining, classifying the degree of liver fibrosis, and detecting the expression of type I and III collagen and TGF-{beta}1; the remaining liver samples were stored in liquid nitrogen to be used for detecting TGF-{beta}1 by Western blotting and for measuring the mRNA expression of type I and III collagen and TGF-{beta}1 by quantitative real-time polymerase chain reaction. Results: Comparing the TGF-{beta}1 siRNA 0.25 mg/kg treatment group to the model group, the TGF-{beta}1 siRNA negative control group and the TGF-{beta}1 siRNA 0.125 mg/kg treatment group showed significantly reduced levels of pathological changes, protein expression and the m

  7. Integrin αIIb (CD41 plays a role in the maintenance of hematopoietic stem cell activity in the mouse embryonic aorta

    Jean-Charles Boisset


    Integrins are transmembrane receptors that play important roles as modulators of cell behaviour through their adhesion properties and the initiation of signaling cascades. The αIIb integrin subunit (CD41 is one of the first cell surface markers indicative of hematopoietic commitment. αIIb pairs exclusively with β3 to form the αIIbβ3 integrin. β3 (CD61 also pairs with αv (CD51 to form the αvβ3 integrin. The expression and putative role of these integrins during mouse hematopoietic development is as yet unknown. We show here that hematopoietic stem cells (HSCs differentially express αIIbβ3 and αvβ3 integrins throughout development. Whereas the first HSCs generated in the aorta at mid-gestation express both integrins, HSCs from the placenta only express αvβ3, and most fetal liver HSCs do not express either integrin. By using αIIb deficient embryos, we show that αIIb is not only a reliable HSC marker but it also plays an important and specific function in maintaining the HSC activity in the mouse embryonic aorta.

  8. Symbiont-derived beta-1,3-glucanases in a social insect: mutualism beyond nutrition

    Rosengaus, Rebeca B.; Schultheis, Kelley F.; Alla eYalonetskaya; Bulmer, Mark S.; William S DuComb; Benson, Ryan W.; John Paul eThottam; Veronica eGodoy-Carter


    Termites have had a long co-evolutionary history with prokaryotic and eukaryotic gut microbes. Historically, the role of these anaerobic obligate symbionts has been attributed to the nutritional welfare of the host. We provide evidence that protozoa (and/or their associated bacteria) colonizing the hindgut of the dampwood termite Zootermopsis angusticollis, synthesize multiple functional beta-1,3-glucanases, enzymes known for breaking down beta-1,3-glucans, the main component of fungal cell w...

  9. TM4SF5 suppression disturbs integrin α5-related signalling and muscle development in zebrafish.

    Choi, Yoon-Ju; Kim, Hyun Ho; Kim, Jeong-Gyun; Kim, Hye-Jin; Kang, Minkyung; Lee, Mi-Sook; Ryu, Jihye; Song, Haeng Eun; Nam, Seo Hee; Lee, Doohyung; Kim, Kyu-Won; Lee, Jung Weon


    TM4SF5 (transmembrane 4 L six family member 5) is involved in EMT (epithelial-mesenchymal transition) for liver fibrosis and cancer metastasis; however, the function(s) of TM4SF5 during embryogenesis remains unknown. In the present study the effects of TM4SF5 on embryogenesis of zebrafish were investigated. tm4sf5 mRNA was expressed in the posterior somites during somitogenesis and in whole myotome 1 dpf (day post-fertilization). tm4sf5 suppression impaired development of the trunk with aberrant morphology of muscle fibres and altered expression of integrin α5. The arrangement and adhesion of muscle cells were abnormally disorganized in tm4sf5 morphants with reduced muscle fibre masses, where integrin α5-related signalling molecules, including fibronectin, FAK (focal adhesion kinase), vinculin and actin were aberrantly localized, compared with those in control fish. Aberrant muscle developments in tm4sf5 morphants were recovered by additional tm4sf5 or integrin α5 mRNA injection. Such a role for TM4SF5 was observed in the differentiation of C2C12 mouse myoblast cells to multinuclear muscle cells. Taken together, the results show that TM4SF5 controls muscle differentiation via co-operation with integrin α5-related signalling. PMID:24897542

  10. Human fallopian tube epithelium constitutively expresses integrin endometrial receptivity markers: no evidence for a tubal implantation window.

    Brown, J K; Shaw, J L V; Critchley, H O D; Horne, A W


    Understanding of ectopic implantation within the Fallopian tube (FT) is limited. In the human uterus, the putative 'window of implantation' in the mid-luteal phase of the menstrual cycle is accompanied by increased endometrial epithelial expression of the integrins α(1)β(1), α(4)β(1) and α(v)β(3) and its ligand osteopontin. Similar cyclical changes in FT integrin expression have been proposed to contribute to ectopic implantation, but supporting data are limited. In the current study, we present quantitative data on human FT transcription and translation of the integrin subunits α(1), α(4), α(V), β(1) and β(3) during the follicular and mid-luteal phases of the menstrual cycle, together with a supporting immuocytochemical analysis of their spatial distribution within the FT, and that of osteopontin. In contrast to previous studies, our data indicate that all five integrin receptivity markers are constitutively transcribed and translated in the FT, with no evidence for changes in their expression or distribution during the window of implantation in the mid-luteal phase of the cycle. Furthermore, we could find no evidence for cyclic redistribution of the integrin α(v)β(3) ligand osteopontin within the FT. Although we do not rule out the involvement of integrin endometrial receptivity markers in the establishment of ectopic pregnancy, our findings do not support their differential expression during a tubal implantation window. PMID:22002573

  11. Discovery of platyhelminth-specific α/β-integrin families and evidence for their role in reproduction in Schistosoma mansoni.

    Svenja Beckmann

    Full Text Available In all metazoa, the response of cells to molecular stimuli from their environment represents a fundamental principle of regulatory processes controlling cell growth and differentiation. Among the membrane-linked receptors mediating extracellular communication processes are integrin receptors. Besides managing adhesion to the extracellular matrix or to other cells, they arrange information flow into the cells by activating intracellular signaling pathways often acting synergistically through cooperation with growth factor receptors. Although a wealth of information exists on integrins in different model organisms, there is a big gap of knowledge for platyhelminths. Here we report on the in silico detection and reconstruction of α and β integrins from free-living and parasitic platyhelminths, which according to structural and phylogenetic analyses form specific clades separate from each other and from further metazoan integrins. As representative orthologs of parasitic platyhelminths we have cloned one beta-integrin (Smβ-Int1 and four alpha-integrins (Smα-Int1 - Smα-Int4 from Schistosoma mansoni; they were characterized by molecular and biochemical analyses. Evidence is provided that Smβ-Int1 interacts and co-localizes in the reproductive organs with known schistosome cellular tyrosine kinases (CTKs, of which the Syk kinase SmTK4 appeared to be the strongest interaction partner as shown by yeast two-hybrid analyses and coimmunoprecipitation experiments. By a novel RNAi approach with adult schistosomes in vitro we demonstrate for the first time multinucleated oocytes in treated females, indicating a decisive role Smβ-Int1 during oogenesis as phenotypically analyzed by confocal laser scanning microscopy (CLSM. Our findings provide a first comprehensive overview about platyhelminth integrins, of which the parasite group exhibits unique features allowing a clear distinction from the free-living groups. Furthermore, we shed first lights on the

  12. Endocytosis of Integrin-Binding Human Picornaviruses

    Pirjo Merilahti


    Full Text Available Picornaviruses that infect humans form one of the largest virus groups with almost three hundred virus types. They include significant enteroviral pathogens such as rhino-, polio-, echo-, and coxsackieviruses and human parechoviruses that cause wide range of disease symptoms. Despite the economic importance of picornaviruses, there are no antivirals. More than ten cellular receptors are known to participate in picornavirus infection, but experimental evidence of their role in cellular infection has been shown for only about twenty picornavirus types. Three enterovirus types and one parechovirus have experimentally been shown to bind and use integrin receptors in cellular infection. These include coxsackievirus A9 (CV-A9, echovirus 9, and human parechovirus 1 that are among the most common and epidemic human picornaviruses and bind to αV-integrins via RGD motif that resides on virus capsid. In contrast, echovirus 1 (E-1 has no RGD and uses integrin α2β1 as cellular receptor. Endocytosis of CV-A9 has recently been shown to occur via a novel Arf6- and dynamin-dependent pathways, while, contrary to collagen binding, E-1 binds inactive β1 integrin and enters via macropinocytosis. In this paper, we review what is known about receptors and endocytosis of integrin-binding human picornaviruses.

  13. Integrins, muscle agrin and sarcoglycans during muscular inactivity conditions: an immunohistochemical study

    G Anastasi


    Full Text Available Sarcoglycans are transmembrane proteins that seem to be functionally and pathologically as important as dystrophin. Sarcoglycans cluster together to form a complex, which is localized in the cell membrane of skeletal, cardiac, and smooth muscle. It has been proposed that the dystrophin-glycoprotein complex (DGC links the actin cytoskeleton with the extracellular matrix and the proper maintenance of this connection is thought to be crucial to the mechanical stability of the sarcolemma. The integrins are a family of heterodimeric cell surface receptors which play a crucial role in cell adhesion including cell-matrix and intracellular interactions and therefore are involved in various biological phenomena, including cell migration, and differentiation tissue repair. Sarcoglycans and integrins play a mechanical and signaling role stabilizing the systems during cycles of contraction and relaxation.Several studies suggested the possibility that integrins might play a role in muscle agrin signalling. On these basis, we performed an immunohistochemical analyzing sarcoglycans, integrins and agrin, on human skeletal muscle affected by sensitive-motor polyneuropathy, in order to better define the correlation between these proteins and neurogenic atrophy due to peripheral neuropathy. Our results showed the existence of a cascade mechanism which provoke a loss of regulatory effects of muscle activity on costameres, due to loss of muscle and neural agrin.This cascade mechanism could determine a quantitative modification of transmembrane receptors and loss of ?7B could be replaced and reinforced by enhanced expression of the ?7A integrin to restore muscle fiber viability. Second, it is possible that the reduced cycles of contraction and relaxation of muscle fibers, during muscular atrophy, provoke a loss of mechanical stresses transmitted over cell surface receptors that physically couple the cytoskeleton to extracellular matrix. Consequently, these mechanical

  14. Dietary Beta-1,3/1,6-Glucans Reduce Clinical Signs of Canine Atopy

    A. C. Beynen


    Full Text Available Problem statement: There was evidence that beta-1,3/1,6-glucans modulate inflammatory activity. In an open, non-controlled trial, purified beta-1,3/1,6-glucans were found to improve the clinical signs of dogs with undefined chronic skin disorders. Given the design of that study, further work was required on the efficacy of beta-1,3/1,6-glucans in the treatment of canine atopy. Approach: The influence of a purified preparation of beta-1,3/1,6-glucans (MacroGard® on canine atopy was assessed in a double-blind, placebo-controlled trial. Privately owned dogs were used and the clinical signs of atopic dermatitis were evaluated by the owners. For a period of 8 weeks, the dogs daily received a complete dry food without (n = 16 or with 800 ppm beta-1,3/1,6-glucans (n = 15. During the trial, all dogs were treated three times with the use of a flea remedy in order to exclude any influence of flea-bite allergy. To assess the severity of atopic dermatitis, the clinical signs scored were itching, redness, scaling, thickening and stripping of skin. Results: For all five clinical signs, the group-mean improvement, expressed as change of severity score over time, was greater in the test group than in the controls. Within each group, the changes for the five clinical signs were added up to arrive at an overall index of improvement of atopic dermatitis. The extra improvement caused by the ingestion of beta-1,3/1,6-glucans was 63%. The difference between the pooled group-mean changes of the scores for the control and test dogs was statistically significant (PConclusion: Beta-1,3/1,6-glucans can be considered safe and it is put forward that a dose of 800 ppm in a dry food is beneficial for dogs with atopic dermatitis.

  15. IL-4 and TGF-beta 1 counterbalance one another while regulating mast cell homeostasis.

    Macey, Matthew R; Sturgill, Jamie L; Morales, Johanna K; Falanga, Yves T; Morales, Joshua; Norton, Sarah K; Yerram, Nitin; Shim, Hoon; Fernando, Josephine; Gifillan, Alasdair M; Gomez, Gregorio; Schwartz, Lawrence; Oskeritzian, Carole; Spiegel, Sarah; Conrad, Daniel; Ryan, John J


    Mast cell responses can be altered by cytokines, including those secreted by Th2 and regulatory T cells (Treg). Given the important role of mast cells in Th2-mediated inflammation and recent demonstrations of Treg-mast cell interactions, we examined the ability of IL-4 and TGF-beta1 to regulate mast cell homeostasis. Using in vitro and in vivo studies of mouse and human mast cells, we demonstrate that IL-4 suppresses TGF-beta1 receptor expression and signaling, and vice versa. In vitro studies demonstrated that IL-4 and TGF-beta1 had balancing effects on mast cell survival, migration, and FcepsilonRI expression, with each cytokine cancelling the effects of the other. However, in vivo analysis of peritoneal inflammation during Nippostrongylus brasiliensis infection in mice revealed a dominant suppressive function for TGF-beta1. These data support the existence of a cytokine network involving the Th2 cytokine IL-4 and the Treg cytokine TGF-beta1 that can regulate mast cell homeostasis. Dysregulation of this balance may impact allergic disease and be amenable to targeted therapy. PMID:20304823

  16. Synergistic effects of 1,25-Dihydroxyvitamin D3 and TGF-beta1 on the production of insulin-like growth factor binding protein 3 in human bone marrow stromal cell cultures

    Kveiborg, Marie; Flyvbjerg, Allan; Kassem, M


    1,25-Dihydroxyvitamin D3 (calcitriol), transforming growth factor-beta (TGF-beta), and insulin-like growth factors (IGFs) are all important bone regulatory factors known to affect proliferation and differentiation of human bone-forming cells (osteoblasts). We have previously shown that TGF-beta1 ...

  17. HGF Accelerates Wound Healing by Promoting the Dedifferentiation of Epidermal Cells through β1-Integrin/ILK Pathway

    Jin-Feng Li


    Full Text Available Skin wound healing is a critical and complex biological process after trauma. This process is activated by signaling pathways of both epithelial and nonepithelial cells, which release a myriad of different cytokines and growth factors. Hepatocyte growth factor (HGF is a cytokine known to play multiple roles during the various stages of wound healing. This study evaluated the benefits of HGF on reepithelialization during wound healing and investigated its mechanisms of action. Gross and histological results showed that HGF significantly accelerated reepithelialization in diabetic (DB rats. HGF increased the expressions of the cell adhesion molecules β1-integrin and the cytoskeleton remodeling protein integrin-linked kinase (ILK in epidermal cells in vivo and in vitro. Silencing of ILK gene expression by RNA interference reduced expression of β1-integrin, ILK, and c-met in epidermal cells, concomitantly decreasing the proliferation and migration ability of epidermal cells. β1-Integrin can be an important maker of poorly differentiated epidermal cells. Therefore, these data demonstrate that epidermal cells become poorly differentiated state and regained some characteristics of epidermal stem cells under the role of HGF after wound. Taken together, the results provide evidence that HGF can accelerate reepithelialization in skin wound healing by dedifferentiation of epidermal cells in a manner related to the β1-integrin/ILK pathway.

  18. Exercise-induced changes in circulating levels of transforming growth factor-beta-1 in humans

    Heinemeier, Katja; Langberg, Henning; Kjaer, Michael

    resting subjects (reported values range from 500 to 18,300 pg ml(-1)) and also the extent of intra-individual variation is unknown. As a basis for detecting exercise-induced changes in transforming growth factor-beta-1, we measured its concentration, by enzyme-linked immunosorbent assay, in plasma from...... eight healthy resting subjects. Plasma was sampled from each subject on five successive days according to a procedure designed to minimize activation of platelets, as platelet alpha-granules contain large amounts of transforming growth factor-beta-1. The mean plasma level was relatively low [1155 (30......Mechanical loading of cells induces the expression of transforming growth factor-beta-1, and acute exercise, which involves mechanical loading of several tissues, could thus increase its circulating level in humans. However, no consensus exists regarding the plasma concentration of this cytokine in...

  19. Integrin α6Bβ4 inhibits colon cancer cell proliferation and c-Myc activity

    Integrins are known to be important contributors to cancer progression. We have previously shown that the integrin β4 subunit is up-regulated in primary colon cancer. Its partner, the integrin α6 subunit, exists as two different mRNA splice variants, α6A and α6B, that differ in their cytoplasmic domains but evidence for distinct biological functions of these α6 splice variants is still lacking. In this work, we first analyzed the expression of integrin α6A and α6B at the protein and transcript levels in normal human colonic cells as well as colorectal adenocarcinoma cells from both primary tumors and established cell lines. Then, using forced expression experiments, we investigated the effect of α6A and α6B on the regulation of cell proliferation in a colon cancer cell line. Using variant-specific antibodies, we observed that α6A and α6B are differentially expressed both within the normal adult colonic epithelium and between normal and diseased colonic tissues. Proliferative cells located in the lower half of the glands were found to predominantly express α6A, while the differentiated and quiescent colonocytes in the upper half of the glands and surface epithelium expressed α6B. A relative decrease of α6B expression was also identified in primary colon tumors and adenocarcinoma cell lines suggesting that the α6A/α6B ratios may be linked to the proliferative status of colonic cells. Additional studies in colon cancer cells showed that experimentally restoring the α6A/α6B balance in favor of α6B caused a decrease in cellular S-phase entry and repressed the activity of c-Myc. The findings that the α6Bβ4 integrin is expressed in quiescent normal colonic cells and is significantly down-regulated in colon cancer cells relative to its α6Aβ4 counterpart are consistent with the anti-proliferative influence and inhibitory effect on c-Myc activity identified for this α6Bβ4 integrin. Taken together, these findings point out the importance of integrin

  20. Alterated integrin expression in lichen planopilaris

    Erriquez Roberta


    Full Text Available Abstract Background Lichen planopilaris (LPP is an inflammatory disease characterized by a lymphomononuclear infiltrate surrounding the isthmus and infundibulum of the hair follicle of the scalp, that evolves into atrophic/scarring alopecia. In the active phase of the disease hairs are easily plucked with anagen-like hair-roots. In this study we focused on the expression of integrins and basement membrane components of the hair follicle in active LPP lesions. Methods Scalp biopsies were taken in 10 patients with LPP and in 5 normal controls. Using monoclonal antibodies against α3β1 and α6β4 integrins we showed the expression of these integrins and of the basement membrane components of the hair follicle in active LPP lesions and in healthy scalp skin. Results In the LPP involved areas, α3β1 was distributed in a pericellular pattern, the α6 subunit was present with a basolateral distribution while the β4 subunit showed discontinuous expression at the basal pole and occasionally, basolateral staining of the hair follicle. Conclusion: An altered distribution of the integrins in active LPP lesions can explain the phenomenon of easy pulling-out of the hair with a "gelatinous" root-sheath.

  1. Brucella beta 1,2 cyclic glucan is an activator of human and mouse dendritic cells

    A Martirosyan; Perez-Gutierrez, C. (Camino); Banchereau, R; Dutartre, H; Lecine, P.; Dullaers, M. (Melissa); Mello, M.; Pinto, S; Muller, A; Leserman, L; Levy, Y.; Zurawski, G; Zurawski, S; Moreno, E; Moriyon, I


    Bacterial cyclic glucans are glucose polymers that concentrate within the periplasm of alpha-proteobacteria. These molecules are necessary to maintain the homeostasis of the cell envelope by contributing to the osmolarity of Gram negative bacteria. Here, we demonstrate that Brucella beta 1,2 cyclic glucans are potent activators of human and mouse dendritic cells. Dendritic cells activation by Brucella beta 1,2 cyclic glucans requires TLR4, MyD88 and TRIF, but not CD14. The Brucella cyclic glu...

  2. Integrin-mediated function of Rab GTPases in cancer progression

    Alahari Suresh K


    Full Text Available Abstract The RAS (rat sarcoma superfamily of small GTPases is broadly subdivided into five groups: Ras, Rho, Rab, Ran, and Arf. Rab family proteins are important in regulating signal transduction and cellular processes such as differentiation, proliferation, vesicle transport, nuclear assembly, and cytoskeleton formation. However, some Rab proteins have been reported to be necessary for the adhesion and migration of cancer cells. Although Ras and Rho family members have been strongly implicated in cancer progression, knowledge of Rabs action in this regard is limited. Some reports have also linked Rab GTPases with cancer cell migration and invasiveness. This review discusses the implications of the involvement of Rabs in malignant transformation and cancer therapy through integrin-mediated signaling events, with particular emphasis on breast cancer.

  3. Effects of dietary beta-1,3-glucan on the growth, survival, physiological and immune response of marron, Cherax tenuimanus (smith, 1912).

    Sang, Huynh Minh; Fotedar, Ravi


    Six isonitrogenous and isocalorific diets supplemented with five different levels of beta-1,3-glucan (0.08%, 0.1%, 0.2%, 0.4% and 0.8%) were formulated and tested for marron (Cherax tenuimanus) growth, survival, organosomatic indices, osmoregulatory capacity and immunological parameters (total and differential haemocyte counts, haemolymph clotting time and bacteraemia). The sixth diet without any beta-1,3-glucan was used as a control. Each diet was provided to 18 marron (0.47 +/- 0.02 g initial weight) replicated 3 times in individual 250 L fiberglass cylindrical tanks. Each tank was provided with a biological filtration recirculating water system. After 84 days of culture, the survival and yield were higher in the marron fed 0.1% beta glucan supplemented diet. The different levels of beta glucan did not alter any of the physiological parameters of marron. However, dietary supplementation with beta glucan resulted in significantly higher (P < 0.05) total haemocyte count (THC) and granular cells. The bacteraemia rank was lower in all diets having beta glucan supplemented with more than or equal to 0.1% compared to the control and 0.08% beta glucan supplemented diets. Results suggest that dietary beta-1,3-glucan at a minimum concentration of 0.1-0.2% can improve the immune system of marron. PMID:20139008

  4. ADAM12/syndecan-4 signaling promotes beta 1 integrin-dependent cell spreading through protein kinase Calpha and RhoA

    Thodeti, Charles Kumar; Albrechtsen, Reidar; Grauslund, Morten;


    The ADAMs (a disintegrin and metalloprotease) comprise a large family of multidomain proteins with cell-binding and metalloprotease activities. The ADAM12 cysteine-rich domain (rADAM12-cys) supports cell attachment using syndecan-4 as a primary cell surface receptor that subsequently triggers bet...

  5. Proinsulin C-peptide antagonizes the profibrotic effects of TGF-beta1 via up-regulation of retinoic acid and HGF-related signaling pathways.

    Hills, Claire E; Willars, Gary B; Brunskill, Nigel J


    Novel signaling roles for C-peptide have recently been discovered with evidence that it can ameliorate complications of type 1 diabetes. Here we sought to identify new pathways regulated by C-peptide of relevance to the pathophysiology of diabetic nephropathy. Microarray analysis was performed to identify genes regulated by either C-peptide and/or TGF-beta1 in a human proximal tubular cell line, HK-2. Expression of retinoic acid receptor beta (RARbeta), hepatocyte growth factor (HGF), cellular retinoic acid-binding protein II (CRABPII), vimentin, E-cadherin, Snail, and beta-catenin was assessed by immunoblotting. The cellular localization of vimentin and beta-catenin was determined by immunocytochemistry. Changes in cell morphology were assessed by phase contrast microscopy. Gene expression profiling demonstrated differential expression of 953 and 1458 genes after C-peptide exposure for 18 h or 48 h, respectively. From these, members of the antifibrotic retinoic acid (RA)- and HGF-signaling pathways were selected. Immunoblotting demonstrated that C-peptide increased RARbeta, CRABPII, and HGF. We confirmed a role for RA in reversal of TGF-beta1-induced changes associated with epithelial-mesenchymal transition, including expression changes in Snail, E-cadherin, vimetin, and redistribution of beta-catenin. Importantly, these TGF-beta1-induced changes were inhibited by C-peptide. Further, effects of TGF-beta1 on Snail and E-cadherin expression were blocked by HGF, and inhibitory effects of C-peptide were removed by blockade of HGF activity. This study identifies a novel role for HGF as an effector of C-peptide, possibly via an RA-signaling pathway, highlighting C-peptide as a potential therapy for diabetic nephropathy. PMID:20197308

  6. The function of the human interferon-beta 1a glycan determined in vivo

    Dissing-Olesen, Lasse; Thaysen-Andersen, Morten; Meldgaard, Michael; Højrup, Peter; Finsen, Bente


    counterpart, due to a protein stabilization/solubilization effect of the glycan. It is interesting to note that the terminating sialic acids were essential for these effects. Conclusively, the structure/bioactivity relationship of rhIFN-beta1a was determined in vivo, and it provided a novel insight into the...

  7. Natalizumab plus interferon beta-1a reduces lesion formation in relapsing multiple sclerosis

    Radue, Ernst-Wilhelm; Stuart, William H; Calabresi, Peter A;


    The SENTINEL study showed that the addition of natalizumab improved outcomes for patients with relapsing multiple sclerosis (MS) who had experienced disease activity while receiving interferon beta-1a (IFNbeta-1a) alone. Previously unreported secondary and tertiary magnetic resonance imaging (MRI...

  8. Long-term impact of interferon beta-1b in patients with CIS

    Edan, G; Kappos, L; Montalbán, X;


    OBJECTIVE: To examine the long-term impact of early treatment initiation of interferon beta-1b (IFNB1b, Betaferon/Betaseron) in patients with a first event suggestive of multiple sclerosis (MS). METHODS: In the original placebo-controlled phase of BENEFIT, patients were randomised to IFNB1b 250 μg...

  9. NMR characterization of a 264-residue hyperthermostable endo-beta-1,3-glucanase.

    Ippel, J.H.; Koutsopoulos, S.; Nabuurs, S.M.; Berkel, W.J. van; Oost, J. van der; Mierlo, C.P. van


    Insight into the hyperthermostable endo-beta-1,3-glucanase pfLamA from Pyrococcus furiosus is obtained by using NMR spectroscopy. pfLamA functions optimally at 104 degrees C and recently the X-ray structure of pfLamA has been obtained at 20 degrees C, a temperature at which the enzyme is inactive. I

  10. Transgenic mice overexpressing the beta 1-adrenergic receptor in adipose tissue are resistant to obesity.

    Soloveva, V; Graves, R A; Rasenick, M M; Spiegelman, B M; Ross, S R


    The ratio of alpha- to beta-receptors is thought to regulate the lipolytic index of adipose depots. To determine whether increasing the activity of the beta 1-adrenergic receptor (AR) in adipose tissue would affect the lipolytic rate or the development of this tissue, we used the enhancer-promoter region of the adipocyte lipid-binding protein (aP2) gene to direct expression of the human beta 1 AR cDNA to adipose tissue. Expression of the transgene was seen only in brown and white adipose tissue. Adipocytes from transgenic mice were more responsive to beta AR agonists than were adipocytes from nontransgenic mice, both in terms of cAMP production and lipolytic rates. Transgenic animals were partially resistant to diet-induced obesity. They had smaller adipose tissue depots than their nontransgenic littermates, reflecting decreased lipid accumulation in their adipocytes. In addition to increasing the lipolytic rate, overexpression of the beta 1 AR induced the abundant appearance of brown fat cells in subcutaneous white adipose tissue. These results demonstrate that the beta 1 AR is involved in both stimulation of lipolysis and the proliferation of brown fat cells in the context of the whole organism. Moreover, it appears that it is the overall beta AR activity, rather than the particular subtype, that controls these phenomena. PMID:8994185

  11. The journey of integrins and partners in a complex interactions landscape studied by super-resolution microscopy and single protein tracking.

    Rossier, Olivier; Giannone, Grégory


    Cells adjust their adhesive and cytoskeletal organizations according to changes in the biochemical and physical nature of their surroundings. In return, by adhering and generating forces on the extracellular matrix (ECM) cells organize their microenvironment. Integrin-dependent focal adhesions (FAs) are the converging zones integrating biochemical and biomechanical signals arising from the ECM and the actin cytoskeleton. Thus, integrin-mediated adhesion and mechanotransduction, the conversion of mechanical forces into biochemical signals, are involved in critical cellular functions such as migration, proliferation and differentiation, and their deregulation contributes to pathologies including cancer. A challenging problem is to decipher how stochastic protein movements and interactions lead to formation of dynamic architecture such as integrin-dependent adhesive structures. In this review, we will describe recent advances made possible by super-resolution microscopies and single molecule tracking approaches that provided new understanding on the organization and the dynamics of integrins and intracellular regulators at the nanoscale in living cells. PMID:26571074

  12. Transforming growth factor beta 1-induced changes in cell migration, proliferation, and angiogenesis in the chicken chorioallantoic membrane


    Application of TGF beta 1 (10-100 ng) to the chicken chorioallantoic membrane (CAM) for 72 h resulted in a dose-dependent, gross angiogenic response. The vascular effects induced by TGF beta 1 were qualitatively different than those induced by maximal doses of basic FGF (bFGF) (500 ng). While TGF beta 1 induced the formation of large blood vessels by 72 h, bFGF induced primarily small blood vessels. Histologic analysis revealed that TGF beta 1 stimulated pleiotropic cellular responses in the ...

  13. Tyrosine dephosphorylation of nuclear proteins mimics transforming growth factor beta 1 stimulation of alpha 2(I) collagen gene expression.

    Greenwel, P; Hu, W.; Kohanski, R A; Ramirez, F.


    Transforming growth factor beta 1 (TGF-beta 1) exerts a positive effect on the transcription of genes coding for several extracellular matrix-related products, including collagen I. We have previously identified a strong TGF-beta 1-responsive element (TbRE) in the upstream promoter sequence of the alpha 2(I) collagen (COL1A2) gene. Our experiments have shown that TGF-beta 1 stimulates COL1A2 transcription by increasing binding of an Sp1-containing complex (TbRC) to the TbRE. They have also su...

  14. Patient satisfaction with the BETACONNECT™ autoinjector for interferon beta-1b

    Weller I


    Full Text Available Ivonne Weller,1 Anna Saake,1 Thomas Schreiner,1 Julika Vogelreuter,1 Nicolas Petroff2 1Bayer Vital GmbH, Leverkusen, Germany; 2Vitartis Medizin-Service GmbH, Göttingen, Germany Purpose: Multiple sclerosis (MS is a chronic demyelinating, degenerative disease requiring long-term treatment. Patient adherence to treatment may be challenging in such scenarios, especially since treatment often involves self-injection, for example, with interferon beta-1b during therapy. BETACONNECT™ is a novel electronic autoinjector for patient support in interferon beta-1b administration. The purpose of this survey was to assess patient satisfaction with the BETACONNECT™ device and its features.Patients and methods: A total of 2,299 MS patients using the BETACONNECT™ device were asked to participate in a survey in October 2014. All of these candidates participated in the BETAPLUS® program and had provided written informed consent. The participants were asked to answer 13 device-related questions.Results: Of these candidates, 1,365 replied to the questionnaire, with more than 60% of the participants being 40–59 years of age. Among them, 69% were women and 21% were men (10% not specified. Approximately half of the participants received treatment with interferon beta-1b for more than 5 years. Most participants (85% had used self-injection devices before, with 59% previously using BETACOMFORT®, 23% using BETAJECT® Comfort, and 3% using BETAJECT® Lite, while less than 4% manually injected interferon beta-1b. The majority of the participants had received the BETACONNECT™ device from a BETAPLUS® nurse (87% and 48% had already used the device for more than 2 months (49% for 2 months or less. Among the participants, more than 90% evaluated the BETACONNECT™ device as “very helpful” or “helpful” in supporting their interferon beta-1b therapy with only marginal sex differences. Features that were rated “very important” by more than half of the

  15. α-Spectrin and integrins act together to regulate actomyosin and columnarization, and to maintain a monolayered follicular epithelium.

    Ng, Bing Fu; Selvaraj, Gokul Kannan; Santa-Cruz Mateos, Carmen; Grosheva, Inna; Alvarez-Garcia, Ines; Martín-Bermudo, María Dolores; Palacios, Isabel M


    The spectrin cytoskeleton crosslinks actin to the membrane, and although it has been greatly studied in erythrocytes, much is unknown about its function in epithelia. We have studied the role of spectrins during epithelia morphogenesis using theDrosophilafollicular epithelium (FE). As previously described, we show that α-Spectrin and β-Spectrin are essential to maintain a monolayered FE, but, contrary to previous work, spectrins are not required to control proliferation. Furthermore, spectrin mutant cells show differentiation and polarity defects only in the ectopic layers of stratified epithelia, similar to integrin mutants. Our results identify α-Spectrin and integrins as novel regulators of apical constriction-independent cell elongation, asα-Spectrinand integrin mutant cells fail to columnarize. Finally, we show that increasing and reducing the activity of the Rho1-Myosin II pathway enhances and decreases multilayering ofα-Spectrincells, respectively. Similarly, higher Myosin II activity enhances the integrin multilayering phenotype. This work identifies a primary role for α-Spectrin in controlling cell shape, perhaps by modulating actomyosin. In summary, we suggest that a functional spectrin-integrin complex is essential to balance adequate forces, in order to maintain a monolayered epithelium. PMID:26952981

  16. Force via integrins but not E-cadherin decreases Oct3/4 expression in embryonic stem cells

    Highlights: ► Force via integrins or cadherins induces similar cell stiffening responses. ► Force via integrins but not cadherins induces cell spreading. ► Force via integrins but not cadherins induces differentiation of embryonic stem cells. -- Abstract: Increasing evidence suggests that mechanical factors play a critical role in fate decisions of stem cells. Recently we have demonstrated that a local force applied via Arg-Gly-Asp (RGD) peptides coated magnetic beads to mouse embryonic stem (ES) cells increases cell spreading and cell stiffness and decreases Oct3/4 (Pou5f1) gene expression. However, it is not clear whether the effects of the applied stress on these functions of ES cells can be extended to natural extracellular matrix proteins or cell–cell adhesion molecules. Here we show that a local cyclic shear force applied via fibronectin or laminin to integrin receptors increased cell spreading and stiffness, downregulated Oct3/4 gene expression, and decreased cell proliferation rate. In contrast, the same cyclic force applied via cell–cell adhesion molecule E-cadherin (Cdh1) had no effects on cell spreading, Oct3/4 gene expression, and the self-renewal of mouse ES cells, but induced significant cell stiffening. Our findings demonstrate that biological responses of ES cells to force applied via integrins are different from those to force via E-cadherin, suggesting that mechanical forces might play different roles in different force transduction pathways to shape early embryogenesis.

  17. Direct interaction of the kringle domain of urokinase-type plasminogen activator (uPA) and integrin alpha v beta 3 induces signal transduction and enhances plasminogen activation.

    Tarui, Takehiko; Akakura, Nobuaki; Majumdar, Mousumi; Andronicos, Nicholas; Takagi, Junichi; Mazar, Andrew P; Bdeir, Khalil; Kuo, Alice; Yarovoi, Serge V; Cines, Douglas B; Takada, Yoshikazu


    It has been questioned whether there are receptors for urokinase-type plasminogen activator (uPA) that facilitate plasminogen activation other than the high affinity uPA receptor (uPAR/CD87) since studies of uPAR knockout mice did not support a major role of uPAR in plasminogen activation. uPA also promotes cell adhesion, chemotaxis, and proliferation besides plasminogen activation. These uPA-induced signaling events are not mediated by uPAR, but mediated by unidentified, lower-affinity receptors for the uPA kringle. We found that uPA binds specifically to integrin alpha v beta 3 on CHO cells depleted of uPAR. The binding of uPA to alpha v beta 3 required the uPA kringle domain. The isolated uPA kringle domain binds specifically to purified, recombinant soluble, and cell surface alpha v beta 3, and other integrins (alpha 4 beta 1 and alpha 9 beta 1), and induced migration of CHO cells in an alpha v beta 3-dependent manner. The binding of the uPA kringle to alpha v beta 3 and uPA kringle-induced alpha v beta 3-dependent cell migration were blocked by homologous plasminogen kringles 1-3 or 1-4 (angiostatin), a known integrin antagonist. We studied whether the binding of uPA to integrin alpha v beta 3 through the kringle domain plays a role in plasminogen activation. On CHO cell depleted of uPAR, uPA enhanced plasminogen activation in a kringle and alpha v beta 3-dependent manner. Endothelial cells bound to and migrated on uPA and uPA kringle in an alpha v beta 3-dependent manner. These results suggest that uPA binding to integrins through the kringle domain plays an important role in both plasminogen activation and uPA-induced intracellular signaling. The uPA kringle-integrin interaction may represent a novel therapeutic target for cancer, inflammation, and vascular remodeling. PMID:16525582

  18. β1 Integrins Mediate Mechanosensitive Signaling Pathways in Osteocytes

    Litzenberger, Julie B.; Tummala, Padmaja; Kim, Jae-Beom; Jacobs, Christopher R.


    Integrins are cell-substrate adhesion proteins that initiate intracellular signaling and may serve as mechanosensors in bone. MLO-Y4 cells were stably transfected with a dominant negative form of the β1 integrin subunit (β1DN) containing the transmembrane domain and cytoplasmic tail of β1 integrin. Cells expressing β1DN had reduced vinculin localization to focal contacts but no change in intracellular actin organization. When exposed to oscillatory fluid flow, β1DN cells exhibited a significa...

  19. Traction forces mediated by integrin signaling are necessary for definitive endoderm specification.

    Taylor-Weiner, Hermes; Ravi, Neeraja; Engler, Adam J


    Pluripotent embryonic stem cells (ESCs) exert low-traction forces on their niche in vitro whereas specification to definitive endoderm in vivo coincides with force-mediated motility, suggesting a differentiation-mediated switch. However, the onset of contractility and extent to which force-mediated integrin signaling regulates fate choices is not understood. To address the requirement of tractions forces for differentiation, we examined mouse embryonic stem cell (ESC) specification towards definitive endoderm on fibrillar fibronectin containing a deformation-sensitive FRET probe. Inhibiting contractility resulted in an increase in the observed fibronectin FRET intensity ratio but also decreased the amount of phosphorylated nuclear SMAD2, leading to reduced expression of the definitive endoderm marker SOX17. By contrast ESCs maintained in pluripotency medium did not exert significant tractions against the fibronectin matrix. When laminin-111 was added to fibrillar matrices to improve the efficiency of definitive endoderm induction, ESCs decreased their fibronectin traction forces in a laminin-dependent manner; blocking the laminin-binding α3-integrin restored fibronectin matrix deformation and reduced SOX17 expression and SMAD2 phosphorylation, probably because of compensation of inhibitory signaling from SMAD7 after 5 days in culture. These data imply that traction forces and integrin signaling are important regulators of early fate decisions in ESCs. PMID:25908864

  20. Expression of VLA-integrins and their related basement membrane ligands in gingiva from patients of various periodontitis categories

    Gürses, N.; Thorup, Alis Karabulut; Reibel, J.; Carter, G.W.; Holmstrup, Palle

    integrins, basement membrane, gingiva, periodontitis, periodontal disease activity immunofluorescence......integrins, basement membrane, gingiva, periodontitis, periodontal disease activity immunofluorescence...

  1. Inhibition of integrin α2β1 ameliorates glomerular injury.

    Borza, Corina M; Su, Yan; Chen, Xiwu; Yu, Ling; Mont, Stacey; Chetyrkin, Sergei; Voziyan, Paul; Hudson, Billy G; Billings, Paul C; Jo, Hyunil; Bennett, Joel S; Degrado, William F; Eckes, Beate; Zent, Roy; Pozzi, Ambra


    Mesangial cells and podocytes express integrins α1β1 and α2β1, which are the two major collagen receptors that regulate multiple cellular functions, including extracellular matrix homeostasis. Integrin α1β1 protects from glomerular injury by negatively regulating collagen production, but the role of integrin α2β1 in renal injury is unclear. Here, we subjected wild-type and integrin α2-null mice to injury with adriamycin or partial renal ablation. In both of these models, integrin α2-null mice developed significantly less proteinuria and glomerulosclerosis. In addition, selective pharmacological inhibition of integrin α2β1 significantly reduced adriamycin-induced proteinuria, glomerular injury, and collagen deposition in wild-type mice. This inhibitor significantly reduced collagen synthesis in wild-type, but not integrin α2-null, mesangial cells in vitro, demonstrating that its effects are integrin α2β1-dependent. Taken together, these results indicate that integrin α2β1 contributes to glomerular injury by positively regulating collagen synthesis and suggest that its inhibition may be a promising strategy to reduce glomerular injury and proteinuria. PMID:22440900

  2. Flavobacterium sp. strain 4221 and Pedobacter sp. strain 4236 beta-1,3-glucanases that are active at low temperatures

    Rasmussen, Mikkel A.; Madsen, Søren; Stougaard, Peter; Johnsen, Mads Grønvald


    Secretion of beta-1,3-glucanases by the arctic bacterial isolates 4221 and 4236, related to the genera Flavobacterium and Pedobacter, was discovered. Escherichia coli and Lactococcus lactis expression of beta-1,3-glucanases Glc4221-1 and Glc4236-1 from the respective isolates was achieved. The en...

  3. Leukocyte arrest: Biomechanics and molecular mechanisms of β2 integrin activation

    Fan, Zhichao; Ley, Klaus


    Integrins are a group of heterodimeric transmembrane receptors that play essential roles in cell–cell and cell–matrix interaction. Integrins are important in many physiological processes and diseases. Integrins acquire affinity to their ligand by undergoing molecular conformational changes called activation. Here we review the molecular biomechanics during conformational changes of integrins, integrin functions in leukocyte biorheology (adhesive functions during rolling and arrest) and molecules involved in integrin activation. PMID:26684674

  4. Role of TGF-beta1 in relation to exercise-induced type I collagen synthesis in human tendinous tissue

    Heinemeier, Katja; Langberg, Henning; Olesen, Jens L;


    Mechanical loading of tissue is known to influence local collagen synthesis, and microdialysis studies indicate that mechanical loading of human tendon during exercise elevates tendinous type I collagen production. Transforming growth factor-beta1 (TGF-beta1), a potent stimulator of type I collagen...... synthesis, is released from cultured tendon fibroblasts in response to mechanical loading. Thus TGF-beta1 could link mechanical loading and collagen synthesis in tendon tissue in vivo. Tissue levels of TGF-beta1 and type I collagen metabolism markers [procollagen I COOH-terminal propeptide (PICP) and COOH......-terminal telopeptide of type I collagen (ICTP)] were measured by microdialysis in peritendinous tissue of the Achilles' tendon in six male volunteers before and after treadmill running (1 h, 12 km/h, 3% uphill). In addition, blood levels of TGF-beta1, PICP, and ICTP were obtained. PICP levels increased 68 h after...

  5. Symbiont-derived beta-1,3-glucanases in a social insect: mutualism beyond nutrition

    Rebeca B Rosengaus


    Full Text Available Termites have had a long co-evolutionary history with prokaryotic and eukaryotic gut microbes. Historically, the role of these anaerobic obligate symbionts has been attributed to the nutritional welfare of the host. We provide evidence that protozoa (and/or their associated bacteria colonizing the hindgut of the dampwood termite Zootermopsis angusticollis, synthesize multiple functional beta-1,3-glucanases, enzymes known for breaking down beta-1,3-glucans, the main component of fungal cell walls. These enzymes, we propose, may help in both digestion of ingested fungal hyphae and protection against invasion by fungal pathogens. This research points to an additional novel role for the mutualistic hindgut microbial consortia of termites, an association that may extend beyond ligno-cellulolytic activity and nitrogen fixation to include a reduction in the risks of mycosis at both the individual- and colony-levels while nesting in and feeding on microbial-rich decayed wood.

  6. Can alterations in integrin and laminin-5 expression be used as markers of malignancy?

    Thorup, Alis Karabulut; Reibel, J.; Schjødt, Morten;


    Integrins, laminin-5, cell adhesion molecules, oral, leukoplakia, premalignant, squamous cell carcinomas......Integrins, laminin-5, cell adhesion molecules, oral, leukoplakia, premalignant, squamous cell carcinomas...

  7. Interaction of interleukin-6 and transforming growth factor-beta1 pathways in prostate epithelial cells

    Staršíchová, Andrea; Lincová, Eva; Pernicová, Zuzana; Kozubík, Alois; Souček, Karel


    Roč. 276, č. 1 (2009), s. 253. ISSN 1742-464X. [34th FEBS Congress. 04.07.2009-09.07.2009, Prague] R&D Projects: GA ČR(CZ) GA204/07/0834 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : transforming growth factor-beta1 * interleukin -6 * prostate Subject RIV: BO - Biophysics

  8. Endothelin-1 activates phospholipase D and thymidine incorporation in fibroblasts overexpressing protein kinase C beta 1.

    Pai, J K; Dobek, E A; Bishop, W R


    Endothelins (ETs) are a family of extremely potent vasoconstrictor peptides. In addition, ET-1 acts as a potent mitogen and activates phospholipase C in smooth muscle cells and fibroblasts. We examined the effects of ET-1 on phosphatidylcholine (PC) metabolism and thymidine incorporation in control Rat-6 fibroblasts and in cells that overexpress protein kinase C beta 1 (PKC). PC pools were labeled with [3H]myristic acid, and formation of phosphatidylethanol (PEt), an unambiguous marker of pho...

  9. Renal thrombotic microangiopathy caused by interferon beta-1a treatment for multiple sclerosis

    Mahe J


    Full Text Available Julien Mahe,1 Aurélie Meurette,2 Anne Moreau,3 Caroline Vercel,2 Pascale Jolliet1,4 1Clinical Pharmacology Department, Institute of Biology, University Hospital, Nantes, France; 2Clinical Nephrology and Immunology Department, University Hospital, Nantes, France; 3Laboratory of Pathology, University Hospital, Nantes, France; 4EA 4275 Biostatistics, Pharmacoepidemiology and Subjective Measures in Health Sciences, University of Nantes, Nantes, France Abstract: Interferon beta-1a is available as an immunomodulating agent for relapsing forms of multiple sclerosis. Common side effects include flu-like symptoms, asthenia, anorexia, and administration site reaction. Kidney disorders are rarely reported. In this study we describe the case of a woman who has been undergoing treatment with interferon beta-1a for multiple sclerosis for 5 years. She developed a hemolytic-uremic syndrome with intravascular hemolysis in a context of severe hypertension. A kidney biopsy showed a thrombotic microangiopathy. This observation highlights an uncommon side effect of long-term interferon beta-1a therapy. Pathophysiological mechanisms leading to this complication might be explained by the antiangiogenic activity of interferon. Keywords: thrombotic microangiopathy, interferon beta, hemolytic-uremic syndrome, antiangiogenic activity

  10. Crosstalk between Fibroblast Growth Factor (FGF Receptor and Integrin through Direct Integrin Binding to FGF and Resulting Integrin-FGF-FGFR Ternary Complex Formation

    Seiji Mori


    Full Text Available Fibroblast growth factors (FGFs play a critical role in diverse physiological processes and the pathogenesis of diseases. Integrins are involved in FGF signaling, since integrin antagonists suppress FGF signaling. This is called integrin-FGF crosstalk, while the specifics of the crosstalk are unclear. This review highlights recent findings that FGF1 directly interacts with integrin αvβ3, and the resulting integrin-FGF-fibroblast growth factor receptor (FGFR ternary complex formation is essential for FGF1-induced cell proliferation, migration and angiogenesis. An integrin-binding defective FGF1 mutant (Arg-50 to Glu, R50E is defective in ternary complex formation and in inducing cell proliferation, migration and angiogenesis, while R50E still binds to the FGF receptor and heparin. In addition, R50E suppressed tumorigenesis in vivo, while wild-type (WT FGF1 enhanced it. Thus, the direct interaction between FGF1 and integrin αvβ3 is a potential therapeutic target, and R50E is a potential therapeutic agent.

  11. Functional consequences of integrin gene mutations in mice

    Bouvard, D; Brakebusch, C; Gustafsson, E; Aszódi, A; Bengtsson, T; Berna, A; Fässler, R


    Integrins are cell-surface receptors responsible for cell attachment to extracellular matrices and to other cells. The application of mouse genetics has significantly increased our understanding of integrin function in vivo. In this review, we summarize the phenotypes of mice carrying mutant inte...

  12. TGF-beta 1 attenuates myocardial ischemia-reperfusion injury via inhibition of upregulation of MMP-1.

    Chen, Hongjiang; Li, Dayuan; Saldeen, Tom; Mehta, Jawahar L


    Ischemia-reperfusion (I/R) is thought to upregulate the expression and activity of matrix metalloproteinases (MMPs), which regulate myocardial and vascular remodeling. Previous studies have shown that transforming growth factor-beta(1) (TGF-beta(1)) can attenuate myocardial injury induced by I/R. TGF-beta(1) is also reported to suppress the release of MMPs. To study the modulation of MMP-1 by TGF-beta(1) in I/R myocardium, Sprague-Dawley rats were given saline and subjected to 1 h of myocardial ischemia [total left coronary artery (LCA) ligation] followed by 1 h of reperfusion (n = 9). Parallel groups of rats were pretreated with recombinant TGF-beta(1) (rTGF-beta(1), 1 mg/rat, n = 9) before reperfusion or exposure to sham I/R (control group). I/R caused myocardial necrosis and dysfunction, indicated by decreased first derivative of left ventricular pressure, mean arterial blood pressure, and heart rate (all P injury and death of cultured myocytes, measured as lactate dehydrogenase release and trypan blue staining, in a dose- and time-dependent manner (P injury and death induced by active MMP-1. The present study for the first time shows that MMP-1 can directly cause myocyte injury or death and that attenuation of myocardial I/R injury by TGF-beta(1) may, at least partly, be mediated by the inhibition of upregulation of MMP-1. PMID:12679326

  13. On gaps in Rényi $\\beta$-expansions of unity for $\\beta > 1$ an algebraic number.

    Verger-Gaugry, Jean-Louis


    Let $\\beta> 1$ be an algebraic number. We study the strings of zeros (“gaps”) in the Rényi $\\beta$ -expansion $d_{\\beta}(1)$ of unity which controls the set $\\mathbb{Z}_{\\beta}$ of $\\beta$-integers. Using a version of Liouville's inequality which extends Mahler's and Güting's approximation theorems, the strings of zeros in $d_{\\beta}(1)$ are shown to exhibit a “gappiness” asymptotically bounded above by $log(M(\\beta ))/ log(\\beta)$, where $M(\\beta)$ is the Mahler measure of $\\beta$ . The proo...

  14. Chain specificity assignment of monoclonal antibodies to human laminins by using recombinant laminin beta1 and gamma1 chains.

    Geberhiwot, T; Wondimu, Z; Salo, S; Pikkarainen, T; Kortesmaa, J; Tryggvason, K; Virtanen, I; Patarroyo, M


    In the present study, the chain specificity of 16 commonly used monoclonal antibodies to human laminin(s) was analysed by using recombinant laminin beta1 and gamma1 chains. By ELISA, all antibodies reacted with purified placenta laminin, and most antibodies recognised either recombinant beta1 or gamma1 chains. Reactivity and chain specificity was confirmed against the recombinant chains in Western blotting under non-reducing conditions, and only a few antibodies were reactive under reducing conditions. Most antibodies were able to immunoprecipitate associated laminin beta1/gamma1 chains from platelet lysates. Based on these results and data from the literature, a tentative epitope map is presented. PMID:10842099

  15. Lamellipodial tension, not integrin/ligand binding, is the crucial factor to realise integrin activation and cell migration.

    Schulte, Carsten; Ferraris, Gian Maria Sarra; Oldani, Amanda; Galluzzi, Massimiliano; Podestà, Alessandro; Puricelli, Luca; de Lorenzi, Valentina; Lenardi, Cristina; Milani, Paolo; Sidenius, Nicolai


    The molecular clutch (MC) model proposes that actomyosin-driven force transmission permits integrin-dependent cell migration. To investigate the MC, we introduced diverse talin (TLN) and integrin variants into Flp-In™ T-Rex™ HEK293 cells stably expressing uPAR. Vitronectin variants served as substrate providing uPAR-mediated cell adhesion and optionally integrin binding. This particular system allowed us to selectively analyse key MC proteins and interactions, effectively from the extracellular matrix substrate to intracellular f-actin, and to therewith study mechanobiological aspects of MC engagement also uncoupled from integrin/ligand binding. With this experimental approach, we found that for the initial PIP2-dependent membrane/TLN/f-actin linkage and persistent lamellipodia formation the C-terminal TLN actin binding site (ABS) is dispensable. The establishment of an adequate MC-mediated lamellipodial tension instead depends predominantly on the coupling of this C-terminal TLN ABS to the actomyosin-driven retrograde actin flow force. This lamellipodial tension is crucial for full integrin activation eventually determining integrin-dependent cell migration. In the integrin/ligand-independent condition the frictional membrane resistance participates to these processes. Integrin/ligand binding can also contribute but is not necessarily required. PMID:26616200

  16. IFN beta 1a as Glucocorticoids-Sparing Therapy in a Patient with CLIPPERS

    Rico, María; Villafani, Javier; Tuñón, Alberto; Mateos, Valentín; Oliva-Nacarino, Pedro


    Patient: Male, 31 Final Diagnosis: CLIPPERS Symptoms: Ataxia • diplopia Medication: IFNbeta 1a Clinical Procedure: — Specialty: Neurology Objective: Rare disease Background: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a recently described inflammatory disease of the central nervous system, distinguished by brainstem- and spinal cord-centered lesions with a characteristic contrast enhancement on MRI, a lymphocytic perivascular infiltrate on pathological exam, and a dramatic response to and dependence on steroids therapy. Since its initial description in 2010, different glucocorticoid-sparing agents, mostly immunosuppressant drugs, have been used to minimize the dosage, but these therapies also carry the risk of important secondary effects. We present the first reported case of CLIPPERS treated with interferon beta 1a as add-on therapy. Case Report: A previously healthy 31-year-old man presented with gait ataxia and dysarthria. MRI showed pons-centered hyperintense patchy lesions on T2-weighted images. Additional tests ruled out other possible diagnoses and symptoms reversed with intravenous methylprednisolone. Over the years the patient presented with several episodes of deterioration each year, which were partly reversed with glucocorticoid therapy, but leaving him with growing sequelae. Four years after the initial event, treatment with interferon-beta-1a was initiated, achieving reduced frequency of the relapses to 1 every 4 years, which were no longer associated to increasing disability. This allowed reducing glucocorticoids to 30 mg of Deflazacort every other day. Conclusions: Interferon beta-1a could be an alternative to corticosteroid-combined therapy in CLIPPERS and its more benign profile of secondary effects compared to immunosuppressants could make it an attractive choice. PMID:26813773

  17. Exposure to particulates, microorganisms, beta(1-3)-glucans, and endotoxins during soybean harvesting.

    Roy, Chad J; Thorne, Peter S


    Sclerotinia sclerotiorum is an emerging fungal pathogen affecting soybeans in the United States. In response to its emergence, exposures to particulates, bioaerosols, endotoxins, S. sclerotiorum, and beta(1-3)-glucans were characterized during soybean harvesting. Air sampling was performed on soybean harvesters (combines) and on the farmers in closed cabs as personal samples during harvesting at 17 farms in 1997 and repeated at 15 in 1998. S. sclerotiorum infestation was evident in the fields at 8 of the sites (44%). The geometric mean concentrations (and geometric standard deviations) measured on the combines in 1998 were as follows: total dust, 11.9 (2.8) mg/m(3); inhalable dust 11.7 (6.4) mg/m(3); and beta(1-3)-glucans, 5027 (7) ng/m(3). Values for the personal samples in 1998 were as follows: total dust, 1.2 (6.7) mg/m(3); inhalable dust, 1.1 (5.3); and beta(1-3)-glucans, 674 (9) ng/m(3). These concentrations were two- to threefold higher than in the previous year. Ambient endotoxin concentrations were 4438 EU/m(3) in Year I and 459 EU/m(3) in Year II. Particle size distribution measurements on the combines yielded mass median aerodynamic diameters of 6.6 microm on the combine and 4.0 microm inside the combine cab. Closed combine cabs provided an average workplace protection factor of 11.7 for total dust. Nevertheless, personal exposures to organisms inside combine cabins ranged from 3.6 x 10(4) to 4.0 x 10(8) organisms/m(3). These data indicate the potential exists for high exposures to organic dust and bioaerosols during soybean harvesting. PMID:12908864

  18. Research of TGF-beta1 Inducing Lung Adencarcinoma PC9 Cells to Mesenchymal Cells Transition

    Chen, Xiaofeng; Wang, Heyong; Zhang, Lei; Zhang, Huijun


    Background and objective It has been proven that epithelial-mesenchymal transition (EMT) not only correlated with embryonic development but also could promote tumor invasion and metastasis. Transforming growth factor beta-1 (TGF-β1) has been identified as the main inducer of tumor EMT. The aim of this study was to investigate the effects of TGF-β1 on EMT and PI3K/AKT signaling pathway in lung adencarcinoma PC9 cells. Methods Cultured PC9 cells were treated with different concentrations of TGF...

  19. VLA-4 integrin concentrates at the peripheral supramolecular activation complex of the immune synapse and drives T helper 1 responses

    Mittelbrunn, María; Molina, Ana; Escribese, María M.; Yáñez-Mó, María; Escudero, Ester; Ursa, Ángeles; Tejedor, Reyes; Mampaso, Francisco; Sánchez-Madrid, Francisco


    The integrin 41 (VLA-4) not only mediates the adhesion and transendothelial migration of leukocytes, but also provides costimulatory signals that contribute to the activation of T lymphocytes. However, the behavior of 41 during the formation of the immune synapse is currently unknown. Here, we show that 41 is recruited to both human and murine antigen-dependent immune synapses, when the antigen-presenting cell is a B lymphocyte or a dendritic cell, colocalizing with LFA-1 at the peripheral supramolecular activation complex. However, when conjugates are formed in the presence of anti-4 antibodies, VLA-4 colocalizes with the CD3- chain at the center of the synapse. In addition, antibody engagement of 4 integrin promotes polarization toward a T helper 1 (Th1) response in human in vitro models of CD4+ T cell differentiation and naïve T cell priming by dendritic cells. The in vivo administration of anti-4 integrin antibodies also induces an immune deviation to Th1 response that dampens a Th2-driven autoimmune nephritis in Brown Norway rats. These data reveal a regulatory role of 4 integrins on T lymphocyte-antigen presenting cell cognate immune interactions.

  20. FAK, talin and PIPKIγ regulate endocytosed integrin activation to polarize focal adhesion assembly.

    Nader, Guilherme P F; Ezratty, Ellen J; Gundersen, Gregg G


    Integrin endocytic recycling is critical for cell migration, yet how recycled integrins assemble into new adhesions is unclear. By synchronizing endocytic disassembly of focal adhesions (FAs), we find that recycled integrins reassemble FAs coincident with their return to the cell surface and dependent on Rab5 and Rab11. Unexpectedly, endocytosed integrins remained in an active but unliganded state in endosomes. FAK and Src kinases co-localized with endocytosed integrin and were critical for FA reassembly by regulating integrin activation and recycling, respectively. FAK sustained the active integrin conformation by maintaining talin association with Rab11 endosomes in a type I phosphatidylinositol phosphate kinase (PIPKIγ)-dependent manner. In migrating cells, endocytosed integrins reassembled FAs polarized towards the leading edge, and this polarization required FAK. These studies identify unanticipated roles for FA proteins in maintaining endocytosed integrin in an active conformation. We propose that the conformational memory of endocytosed integrin enhances polarized reassembly of FAs to enable directional cell migration. PMID:27043085

  1. Human Pregnancy Specific Beta-1-Glycoprotein 1 (PSG1) Has a Potential Role in Placental Vascular Morphogenesis1

    Ha, Cam T.; Wu, Julie A.; Irmak, Ster; Lisboa, Felipe A.; Dizon, Anne M.; Warren, James W; Ergun, Suleyman; Dveksler, Gabriela S.


    Previous studies suggest that human pregnancy specific beta-1-glycoproteins (PSGs) play immunomodulatory roles during pregnancy; however, other possible functions of PSGs have yet to be explored. We have observed that PSGs induce transforming growth factor beta 1 (TGFB1), which among its other diverse functions inhibits T-cell function and has proangiogenic properties. The present study investigates a potential role for PSG1, the most abundant PSG in maternal serum, as a possible inducer of p...

  2. Downregulation of IL-6-induced STAT3 tyrosine phosphorylation by TGF-beta 1 is mediated by caspase-dependent and -independent processes

    Wierenga, ATJ; Schuringa, JJ; Eggen, BJL; Kruijer, W; Vellenga, E


    To explore the possible cross-talk between the IL-6 and TGF-beta1 pathways in AML blast cells, the effect of TGF-beta1 pretreatment on IL-6-induced STAT3 tyrosine phosphorylation was studied. A reduction of STAT3 tyrosine phosphorylation after TGF-beta1 pretreatment was observed in four out of 40 AM

  3. Bone response and mechanical strength of rabbit femoral defects filled with injectable CaP cements containing TGF-beta 1 loaded gelatin microparticles.

    Link, D.P.; Dolder, J. van den; Beucken, J.J.J.P van den; Wolke, J.G.C.; Mikos, A.G.; Jansen, J.A.


    This study focused at the potential of transforming growth factor beta 1 (TGF-beta 1) loaded gelatin microparticles to enhance the bone response and mechanical strength of rabbit femoral defects filled with injectable calcium phosphate (CaP)/gelatin microparticle composites. Therefore, TGF-beta1 loa

  4. TGF beta-1 dependent fast stimulation of ATM and p53 phosphorylation following exposure to ionizing radiation does not involve TGF beta-receptor I signalling

    Wiegman, Erwin M.; Blaese, Marcet A.; Loeffler, Heidi; Coppes, Rob P.; Rodemann, H. Peter


    Background and purpose: It has been proposed that radiation induced stimulation of ATM and downstream components involves activation of TGF beta-1 and that this may be due to TGF beta-1-receptor I-Smad signalling. Therefore, the aim of this study was to clarify the distinct role of TGF beta-1-recept

  5. Suppression of integrin activation by the membrane-distal sequence of the integrin alphaIIb cytoplasmic tail.

    Yamanouchi, Jun; Hato, Takaaki; Tamura, Tatsushiro; Fujita, Shigeru


    Integrin cytoplasmic tails regulate integrin activation including an increase in integrin affinity for ligands. Although there is ample evidence that the membrane-proximal regions of the alpha and beta tails interact with each other to maintain integrins in a low-affinity state, little is known about the role of the membrane-distal region of the alpha tail in regulation of integrin activation. We report a critical sequence for regulation of integrin activation in the membrane-distal region of the alphaIIb tail. Alanine substitution of the RPP residues in the alphaIIb tail rendered alphaIIbbeta3 constitutively active in a metabolic energy-dependent manner. Although an alphaIIb/alpha6Abeta3 chimaeric integrin, in which the alphaIIb tail was replaced by the alpha6A tail, was in an energy-dependent active state to bind soluble ligands, introduction of the RPP sequence into the alpha6A tail inhibited binding of an activation-dependent antibody PAC1. In alphaIIb/alpha6Abeta3, deleting the TSDA sequence from the alpha6A tail or single amino acid substitutions of the TSDA residues inhibited alphaIIb/alpha6Abeta3 activation and replacing the membrane-distal region of the alphaIIb tail with TSDA rendered alphaIIbbeta3 active, suggesting a stimulatory role of TSDA in energy-dependent integrin activation. However, adding TSDA to the alphaIIb tail containing the RPP sequence of the membrane-distal region failed to activate alphaIIbbeta3. These results suggest that the RPP sequence after the GFFKR motif of the alphaIIb tail suppresses energy-dependent alphaIIbbeta3 activation. These findings provide a molecular basis for the regulation of energy-dependent integrin activation by alpha subunit tails. PMID:14723599

  6. Angiotensin II increases CTGF expression via MAPKs/TGF-{beta}1/TRAF6 pathway in atrial fibroblasts

    Gu, Jun [Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University School of medicine, Shanghai (China); Liu, Xu, E-mail: [Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University School of medicine, Shanghai (China); Wang, Quan-xing, E-mail: [National Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai (China); Tan, Hong-wei [Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University School of medicine, Shanghai (China); Guo, Meng [National Key Laboratory of Medical Immunology, Second Military Medical University, Shanghai (China); Jiang, Wei-feng; Zhou, Li [Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University School of medicine, Shanghai (China)


    The activation of transforming growth factor-{beta}1(TGF-{beta}1)/Smad signaling pathway and increased expression of connective tissue growth factor (CTGF) induced by angiotensin II (AngII) have been proposed as a mechanism for atrial fibrosis. However, whether TGF{beta}1/non-Smad signaling pathways involved in AngII-induced fibrogenetic factor expression remained unknown. Recently tumor necrosis factor receptor associated factor 6 (TRAF6)/TGF{beta}-associated kinase 1 (TAK1) has been shown to be crucial for the activation of TGF-{beta}1/non-Smad signaling pathways. In the present study, we explored the role of TGF-{beta}1/TRAF6 pathway in AngII-induced CTGF expression in cultured adult atrial fibroblasts. AngII (1 {mu}M) provoked the activation of P38 mitogen activated protein kinase (P38 MAPK), extracellular signal-regulated kinase 1/2(ERK1/2) and c-Jun NH(2)-terminal kinase (JNK). AngII (1 {mu}M) also promoted TGF{beta}1, TRAF6, CTGF expression and TAK1 phosphorylation, which were suppressed by angiotensin type I receptor antagonist (Losartan) as well as p38 MAPK inhibitor (SB202190), ERK1/2 inhibitor (PD98059) and JNK inhibitor (SP600125). Meanwhile, both TGF{beta}1 antibody and TRAF6 siRNA decreased the stimulatory effect of AngII on TRAF6, CTGF expression and TAK1 phosphorylation, which also attenuated AngII-induced atrial fibroblasts proliferation. In summary, the MAPKs/TGF{beta}1/TRAF6 pathway is an important signaling pathway in AngII-induced CTGF expression, and inhibition of TRAF6 may therefore represent a new target for reversing Ang II-induced atrial fibrosis. -- Highlights: Black-Right-Pointing-Pointer MAPKs/TGF{beta}1/TRAF6 participates in AngII-induced CTGF expression in atrial fibroblasts. Black-Right-Pointing-Pointer TGF{beta}1/TRAF6 participates in AngII-induced atrial fibroblasts proliferation. Black-Right-Pointing-Pointer TRAF6 may represent a new target for reversing Ang II-induced atrial fibrosis.

  7. Cost-effectiveness analysis of peginterferon beta-1a compared with interferon beta-1a and glatiramer acetate in the treatment of relapsing-remitting multiple sclerosis in the United States.

    Hernandez, Luis; Guo, Shien; Kinter, Elizabeth; Fay, Monica


    Objective Peginterferon beta-1a 125 mcg, administered subcutaneously (SC) every 2 weeks, a new disease-modifying therapy (DMT) for relapsing-remitting multiple sclerosis (RRMS), was approved by the US Food and Drug Administration in 2014. This study assesses the cost-effectiveness of peginterferon beta-1a vs interferon beta-1a (44 mcg SC 3 times per week) and glatiramer acetate (20 mg SC once-daily) in the treatment of RRMS from the perspective of a US payer over 10 years. Methods A Markov cohort economic model was developed for this analysis. The model predicts disability progression, occurrence of relapses and other adverse events and translates them into quality-adjusted life years (QALYs) and costs. Natural history data were obtained from the placebo arm of the ADVANCE trial of peginterferon beta-1a, the London Ontario (Canada) database and a large population-based MS survey. Comparative efficacy of each DMT vs placebo was obtained from a network meta-analysis. Costs (in 2014 US dollars) were sourced from public databases and literature. Clinical and economic outcomes were discounted at 3% per year. Results Over 10 years, peginterferon beta-1a was dominant (i.e., more effective and less costly), with cost-savings of $22,070 and additional 0.06 QALYs when compared with interferon beta-1a 44 mcg and with cost-savings of $19,163 and 0.07 QALYs gained when compared with glatiramer acetate 20 mg. Results were most sensitive to variations in the treatment effect of each DMT, treatment acquisition costs of each DMT and the time horizon. Probabilistic sensitivity analyses indicated that peginterferon beta-1a remains dominant in >90% of 5,000 replications compared with either DMTs. Conclusion This analysis suggests that long-term treatment with peginterferon beta-1a improves clinical outcomes at reduced costs compared with interferon beta-1a 44 mcg and glatiramer acetate 20 mg and should be a valuable addition to managed care formularies for treating

  8. Quantitative analysis of transforming growth factor beta 1 mRNA in patients with alcoholic liver disease

    Wei-Xing Chen; You-Ming Li; Chao-Hui Yu; Wei-Min Cai; Min Zheng; Feng Chen


    AIM: To investigate the expression of the transforminggrowth factor beta 1 (TGF- beta 1 ) mRNA in different stagesof alcoholic liver disease (ALD) and its clinical value.METHODS: One hundred and seven male alcoholics weregrouped by clinical findings into four groups: alcoholabusers without liver impairment (n=22 ), alcoholicsteatosis ( n = 30 ); alcoholic hepatitis ( n = 31 ); andalcoholic cirrhosis ( n = 24 ) Using peripheral bloodmononuclear cells(PBMC) as samples the gene expressionof TGF-beta 1 was examined quantitatively by reversetranscription polymerase chain reaction (RT-PCR) and dotblot. There are 34 healthy subjects served as control.RESULTS: The expression of TGF-beta 1 from all ALDpatients was significantly greater than that in controls ( 1. 320± 1.162 vs 0.808±0.276, P<0.001). The differences of theexpressions were significant between the patients from eachgroups ( alcoholic steatosis, alcoholic hepatitis andalcoholic cirrhosis) and the controls ( 1. 168 ± 0.852, 1.462 ±1.657, 1.329± 0.610 vs 0.808 ± 0.276, P< 0.050). Nosignificant differences of TGF -beta 1 mRNA expression wereobserved between alcohol abusers without liver impairmentand controls. The expressions in patients with alcoholichepatitis and alcoholic cirrhosis were significantly greaterthan that in alcohol abusers respectively (1.462 ± 1. 657, 1.329 ± 0. 610 vs 0. 841 ± 0. 706, P < 0. 050). No significantdifferences of TGF -beta 1 mRNA expression were observedbetween alcoholic fatty liver men and alcohol abusers.CONCLUSION: TGF-beta 1 expression level can be a riskfactor for alcoholic liver disease and might be related to theinflammatory activity and fibrosis of the liver in patients .

  9. Skin Necrosis Following a Recombinant Interferon-beta-1b Injection

    Chih-Hsun Yang


    Full Text Available Recombinant interferon beta-1b (INF-β-1b has been proven to be an effective means oftreating relapsing-remitting multiple sclerosis (MS. Adverse reactions to interferon therapyhave been well documented. The most common side effects are transient influenza-likesymptoms, including fever, fatigue, nausea, and myalgia. Cutaneous necrosis has occasionallybeen reported, mostly involving small and limited lesions. This article describes an MSpatient who developed multiple large, deep cutaneous ulcers on INF-β-1b injection sites,which subsequently required surgical treatment. Vessel thrombosis in the subcutaneous fattylayer and the clinical appearance of livedoid erythema beside the ulcers indicated that INF-β-1b may have caused skin necrosis through its vascular effects.

  10. IGF-binding proteins mediate TGF-beta 1-induced apoptosis in bovine mammary epithelial BME-UV1 cells.

    Gajewska, Małgorzata; Motyl, Tomasz


    TGF-beta 1 is an antiproliferative and apoptogenic factor for mammary epithelial cells (MEC) acting in an auto/paracrine manner and thus considered an important local regulator of mammary tissue involution. However, the apoptogenic signaling pathway induced by this cytokine in bovine MEC remains obscure. The present study was focused on identification of molecules involved in apoptogenic signaling of transforming growth factor-beta 1 (TGF-beta 1) in the model of bovine mammary epithelial cell line (BME-UV1). Laser scanning cytometry (LSC), Western blot and electrophoretic mobility shift assay (EMSA) were used for analysis of expression and activity of TGF-beta 1-related signaling molecules. The earliest response occurring within 1-2 h after TGF-beta 1 administration was an induction and activation of R-Smads (Smad2 and Smad3) and Co-Smad (Smad4). An evident formation of Smad-DNA complexes began from 2nd hour after MEC exposure to TGF-beta 1. Similarly to Smads, proteins of AP1 complex: phosphorylated c-Jun and JunD appeared to be early reactive molecules; however, an increase in their expression was detected only in cytosolic fraction. In the next step, an increase of IGF binding protein-3 (IGFBP-3) and IGFBP-4 expression was observed from 6th hour followed by a decrease in the activity of protein kinase B (PKB/Akt), which occurred after 24 h of MEC exposure to TGF-beta 1. The decrease in PKB/Akt activity coincided in time with the decline of phosphorylated Bad expression (inactive form). Present study supported additional evidence that stimulation of insulin-like growth factor I (IGF-I) was associated with complete abrogation of TGF-beta 1-induced activation of Bad and Bax and in the consequence protection against apoptosis. In conclusion, apoptotic effect of TGF-beta 1 in bovine MEC is mediated by IGFBPs and occurs through IGF-I sequestration, resulting in inhibition of PKB/Akt-dependent survival pathway. PMID:15556067