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Sample records for adhesion kinase decreases

  1. Inhibition of focal adhesion kinase (FAK) signaling in focal adhesions decreases cell motility and proliferation.

    OpenAIRE

    1996-01-01

    It has been proposed that the focal adhesion kinase (FAK) mediates focal adhesion formation through tyrosine phosphorylation during cell adhesion. We investigated the role of FAK in focal adhesion structure and function. Loading cells with a glutathione-S-transferase fusion protein (GST-Cterm) containing the FAK focal adhesion targeting sequence, but not the kinase domain, decreased the association of endogenous FAK with focal adhesions. This displacement of endogenous FAK in both BALB/c 3T3 ...

  2. Silencing of focal adhesion kinase by tumor direct injection of small interfering RNA decreases in vivo tumor growth.

    Science.gov (United States)

    Tsutsumi, Kae; Yamaura, Takeshi; Nakajima, Motowo; Honda, Toshiyuki; Kasaoka, Tatsuhiko

    2009-07-01

    Focal adhesion kinase (FAK) is shown to be frequently correlated with malignancy of the tumor and poor prognosis of the diseases.Because FAK resides immediately downstream of the interaction of cell surface adhesion molecules and extracellular matricies, it is considered to be critical to regulate several cellular processes including growth, differentiation, adhesion, motility and apoptosis. However, the studies on the role of FAK related to cell proliferation have been limited even in vitro. Here, in order to validate the role of FAK in in vivo tumor formation and proliferation, we employed direct intratumoral injection of short hairpin RNA (shRNA) targeting FAK with cationic liposome. Using shRNAs targeting FAK selected from the constructed shRNA library for FAK and by optimization of in vivo delivery conditions, we demonstrated different patterns of the association of FAK inhibition with in vivo tumor formation/proliferation inhibition in two models, PC3M heterotopic xenograft and 4T1 orthotopic syngraft models. These observations indicated that the roles of FAK in tumorigenesis are different among the tumor species. In addition, we showed that ERK is the critical MAP kinase in the signaling pathway down stream of FAK in in vivo proliferation of 4T1 tumor cells.

  3. Focal adhesion kinases in adhesion structures and disease.

    Science.gov (United States)

    Eleniste, Pierre P; Bruzzaniti, Angela

    2012-01-01

    Cell adhesion to the extracellular matrix (ECM) is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organization and role of focal adhesions, podosomes, and invadopodia in different cells. In addition, we discuss the role of the tyrosine kinases, FAK, Pyk2, and Src, which are critical for the function of the different adhesion structures. Finally, we discuss the essential role of these tyrosine kinases from the perspective of human diseases.

  4. Focal Adhesion Kinases in Adhesion Structures and Disease

    Directory of Open Access Journals (Sweden)

    Pierre P. Eleniste

    2012-01-01

    Full Text Available Cell adhesion to the extracellular matrix (ECM is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organization and role of focal adhesions, podosomes, and invadopodia in different cells. In addition, we discuss the role of the tyrosine kinases, FAK, Pyk2, and Src, which are critical for the function of the different adhesion structures. Finally, we discuss the essential role of these tyrosine kinases from the perspective of human diseases.

  5. Focal Adhesion Kinases in Adhesion Structures and Disease

    OpenAIRE

    2012-01-01

    Cell adhesion to the extracellular matrix (ECM) is essential for cell migration, proliferation, and embryonic development. Cells can contact the ECM through a wide range of matrix contact structures such as focal adhesions, podosomes, and invadopodia. Although they are different in structural design and basic function, they share common remodeling proteins such as integrins, talin, paxillin, and the tyrosine kinases FAK, Pyk2, and Src. In this paper, we compare and contrast the basic organiza...

  6. Focal adhesion kinase - the reversible molecular mechanosensor

    CERN Document Server

    Bell, Samuel

    2016-01-01

    Sensors are the first element of the pathways that control the response of cells to their environment. After chemical, the next most important cue is mechanical, and protein complexes that produce or enable a chemical signal in response to a mechanical stimulus are called mechanosensors. There is a sharp distinction between sensing an external force or pressure/tension applied to the cell, and sensing the mechanical stiffness of the environment. We call the first mechanosensitivity of the 1st kind, and the latter mechanosensitivity of the 2nd kind. There are two variants of protein complexes that act as mechanosensors of the 2nd kind: producing the one-off or a reversible action. The latent complex of TGF-beta is an example of the one-off action: on the release of active TGF-beta signal, the complex is discarded and needs to be replaced. In contrast, the focal adhesion kinase (FAK) in a complex with integrin is a reversible mechanosensor, which initiates the chemical signal in its active phosphorylated confor...

  7. Endothelial paxillin and focal adhesion kinase (FAK) play a critical role in neutrophil transmigration.

    Science.gov (United States)

    Parsons, Sean A; Sharma, Ritu; Roccamatisi, Dawn L; Zhang, Hong; Petri, Björn; Kubes, Paul; Colarusso, Pina; Patel, Kamala D

    2012-02-01

    During an inflammatory response, endothelial cells undergo morphological changes to allow for the passage of neutrophils from the blood vessel to the site of injury or infection. Although endothelial cell junctions and the cytoskeleton undergo reorganization during inflammation, little is known about another class of cellular structures, the focal adhesions. In this study, we examined several focal adhesion proteins during an inflammatory response. We found that there was selective loss of paxillin and focal adhesion kinase (FAK) from focal adhesions in proximity to transmigrating neutrophils; in contrast the levels of the focal adhesion proteins β1-integrin and vinculin were unaffected. Paxillin was lost from focal adhesions during neutrophil transmigration both under static and flow conditions. Down-regulating endothelial paxillin with siRNA blocked neutrophil transmigration while having no effect on rolling or adhesion. As paxillin dynamics are regulated partly by FAK, the role of FAK in neutrophil transmigration was examined using two complementary methods. siRNA was used to down-regulate total FAK protein while dominant-negative, kinase-deficient FAK was expressed to block FAK signaling. Disruption of the FAK protein or FAK signaling decreased neutrophil transmigration. Collectively, these findings reveal a novel role for endothelial focal adhesion proteins paxillin and FAK in regulating neutrophil transmigration.

  8. Protein kinase C involvement in focal adhesion formation

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1992-01-01

    Matrix molecules such as fibronectin can promote cell attachment, spreading and focal adhesion formation. Although some interactions of fibronectin with cell surface receptors have now been identified, the consequent activation of intracellular messenger systems by cell/matrix interactions have...... still to be elucidated. We show here that the kinase inhibitors H7 and HA1004 reduce focal adhesion and stress fiber formation in response to fibronectin in a dose-dependent manner, and that activators of protein kinase C can promote their formation under conditions where they do not normally form....... Fibroblasts spread within 1h on substrata composed of fibronectin and formed focal adhesions by 3h, as monitored by interference reflection microscopy (IRM) and by labeling for talin, vinculin and integrin beta 1 subunits. In addition, stress fibers were visible. When cells were allowed to spread for 1h...

  9. Structural Insight into the Mechanisms of Targeting and Signaling of Focal Adhesion Kinase

    OpenAIRE

    2002-01-01

    Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase whose focal adhesion targeting (FAT) domain interacts with other focal adhesion molecules in integrin-mediated signaling. Localization of activated FAK to focal adhesions is indispensable for its function. Here we describe a solution structure of the FAT domain bound to a peptide derived from paxillin, a FAK-binding partner. The FAT domain is composed of four helices that form a “right-turn” elongated bundle; the globular fold is ma...

  10. Rho-kinase regulates adhesive and mechanical mechanisms of pulmonary recruitment of neutrophils in abdominal sepsis.

    Science.gov (United States)

    Palani, Karzan; Rahman, Milladur; Hasan, Zirak; Zhang, Su; Qi, Zhongquan; Jeppsson, Bengt; Thorlacius, Henrik

    2012-05-05

    We hypothesized that Rho-kinase signaling plays a role in mechanical and adhesive mechanisms of neutrophil accumulation in lung. Male C57BL/6 mice were treated with the Rho-kinase inhibitor Y-27632 prior to cecal ligation and puncture (CLP). Lung levels of myeloperoxidase (MPO) and histological tissue damage were determined 6h and 24h after CLP. Expression of Mac-1 and F-actin formation in neutrophils were quantified by using flow cytometry 6h after CLP. Mac-1 expression and F-actin formation were also determined in isolated neutrophils up to 3h after stimulation with CXCL2. Labeled and activated neutrophils co-incubated with Y-27632, an anti-Mac-1 antibody and cytochalasin B were adoptively transferred to CLP mice. Y-27632 reduced the CLP-induced pulmonary injury and MPO activity as well as Mac-1 on neutrophils. Neutrophil F-actin formation peaked at 6h and returned to baseline levels 24h after CLP induction. Rho-kinase inhibition decreased CLP-provoked F-actin formation in neutrophils. CXCL2 rapidly increased Mac-1 expression and F-actin formation in neutrophils. Co-incubation with Y-27632 abolished CXCL2-induced Mac-1 up-regulation and formation of F-actin in neutrophils. Notably, co-incubation with cytochalasin B inhibited formation of F-actin but did not reduce Mac-1 expression on activated neutrophils. Adoptive transfer experiments revealed that co-incubation of neutrophils with the anti-Mac-1 antibody or cytochalasin B significantly decreased pulmonary accumulation of neutrophils in septic mice. Our data show that targeting Rho-kinase effectively reduces neutrophil recruitment and tissue damage in abdominal sepsis. Moreover, these findings demonstrate that Rho-kinase-dependent neutrophil accumulation in septic lung injury is regulated by both adhesive and mechanical mechanisms.

  11. Recruitment of focal adhesion kinase and paxillin to β1 integrin promotes cancer cell migration via mitogen activated protein kinase activation

    Directory of Open Access Journals (Sweden)

    Ohannessian Arthur

    2004-05-01

    Full Text Available Abstract Background Integrin-extracellular matrix interactions activate signaling cascades such as mitogen activated protein kinases (MAPK. Integrin binding to extracellular matrix increases tyrosine phosphorylation of focal adhesion kinase (FAK. Inhibition of FAK activity by expression of its carboxyl terminus decreases cell motility, and cells from FAK deficient mice also show reduced migration. Paxillin is a focal adhesion protein which is also phosphorylated on tyrosine. FAK recruitment of paxillin to the cell membrane correlates with Shc phosphorylation and activation of MAPK. Decreased FAK expression inhibits papilloma formation in a mouse skin carcinogenesis model. We previously demonstrated that MAPK activation was required for growth factor induced in vitro migration and invasion by human squamous cell carcinoma (SCC lines. Methods Adapter protein recruitment to integrin subunits was examined by co-immunoprecipitation in SCC cells attached to type IV collagen or plastic. Stable clones overexpressing FAK or paxillin were created using the lipofection technique. Modified Boyden chambers were used for invasion assays. Results In the present study, we showed that FAK and paxillin but not Shc are recruited to the β1 integrin cytoplasmic domain following attachment of SCC cells to type IV collagen. Overexpression of either FAK or paxillin stimulated cancer cell migration on type IV collagen and invasion through reconstituted basement membrane which was dependent on MAPK activity. Conclusions We concluded that recruitment of focal adhesion kinase and paxillin to β1 integrin promoted cancer cell migration via the mitogen activated protein kinase pathway.

  12. Focal adhesion kinase is involved in type III group B streptococcal invasion of human brain microvascular endothelial cells.

    Science.gov (United States)

    Shin, Sooan; Paul-Satyaseela, Maneesh; Maneesh, Paul-Satyaseela; Lee, Jong-Seok; Romer, Lewis H; Kim, Kwang Sik

    2006-01-01

    Group B streptococcus (GBS), the leading cause of neonatal meningitis, has been shown to invade human brain microvascular endothelial cells (HBMEC), which constitute the blood-brain barrier. GBS invasion of HBMEC has been shown to require the host cell actin cytoskeleton rearrangements. The present study examined the mechanisms underlying actin cytoskeleton rearrangements that are involved in type III GBS invasion of HBMEC. We showed that type III GBS invasion was inhibited by genistein, a general tyrosine kinase inhibitor (mean 54% invasion decrease at 100 microM), and LY294002, a phosphatidylinositol 3 (PI3) kinase inhibitor (mean 70% invasion decrease at 50 microM), but not by PP2, an inhibitor of the Src family tyrosine kinases. We subsequently showed that the focal adhesion kinase (FAK) was the one of the host proteins tyrosine phosphorylated by type III GBS. Over-expression of a dominant negative form of the FAK C-terminal domain significantly decreased type III GBS invasion of HBMEC (mean 51% invasion decrease). In addition, we showed that FAK phosphorylation correlated with its association of paxillin, an adapter protein of actin filament, and PI3-kinase subunit p85. This is the first demonstration that FAK phosphorylation and its association with paxillin and PI3 kinase play a key role in type III GBS invasion of HBMEC.

  13. Lubricin: a novel means to decrease bacterial adhesion and proliferation.

    Science.gov (United States)

    Aninwene, George E; Abadian, Pegah N; Ravi, Vishnu; Taylor, Erik N; Hall, Douglas M; Mei, Amy; Jay, Gregory D; Goluch, Edgar D; Webster, Thomas J

    2015-02-01

    This study investigated the ability of lubricin (LUB) to prevent bacterial attachment and proliferation on model tissue culture polystyrene surfaces. The findings from this study indicated that LUB was able to reduce the attachment and growth of Staphylococcus aureus on tissue culture polystyrene over the course of 24 h by approximately 13.9% compared to a phosphate buffered saline (PBS)-soaked control. LUB also increased S. aureus lag time (the period of time between the introduction of bacteria to a new environment and their exponential growth) by approximately 27% compared to a PBS-soaked control. This study also indicated that vitronectin (VTN), a protein homologous to LUB, reduced bacterial S. aureus adhesion and growth on tissue culture polystyrene by approximately 11% compared to a PBS-soaked control. VTN also increased the lag time of S. aureus by approximately 43%, compared to a PBS-soaked control. Bovine submaxillary mucin was studied because there are similarities between it and the center mucin-like domain of LUB. Results showed that the reduction of S. aureus and Staphylococcus epidermidis proliferation on mucin coated surfaces was not as substantial as that seen with LUB. In summary, this study provided the first evidence that LUB reduced the initial adhesion and growth of both S. aureus and S. epidermidis on a model surface to suppress biofilm formation. These reductions in initial bacteria adhesion and proliferation can be beneficial for medical implants and, although requiring more study, can lead to drastically improved patient outcomes.

  14. Targeting Focal Adhesion Kinase Suppresses the Malignant Phenotype in Rhabdomyosarcoma Cells

    Directory of Open Access Journals (Sweden)

    Alicia M. Waters

    2016-08-01

    Full Text Available Despite the tremendous advances in the treatment of childhood solid tumors, rhabdomyosarcoma (RMS continues to provide a therapeutic challenge. Children with metastatic or relapsed disease have a disease-free survival rate under 30%. Focal adhesion kinase (FAK is a nonreceptor tyrosine kinase that is important in many facets of tumorigenesis. Signaling pathways both upstream and downstream to FAK have been found to be important in sarcoma tumorigenesis, leading us to hypothesize that FAK would be present in RMS and would impact cellular survival. In the current study, we showed that FAK was present and phosphorylated in pediatric alveolar and embryonal RMS tumor specimens and cell lines. We also examined the effects of FAK inhibition upon two RMS cell lines utilizing parallel approaches including RNAi and small molecule inhibitors. FAK inhibition resulted in decreased cellular survival, invasion, and migration and increased apoptosis. Furthermore, small molecule inhibition of FAK led to decreased tumor growth in a nude mouse RMS xenograft model. The findings from this study will help to further our understanding of the regulation of tumorigenesis in RMS and may provide desperately needed novel therapeutic strategies for these difficult-to-treat tumors.

  15. How to awaken your nanomachines: Site-specific activation of focal adhesion kinases through ligand interactions

    KAUST Repository

    Walkiewicz, Katarzyna Wiktoria

    2015-06-17

    The focal adhesion kinase (FAK) and the related protein-tyrosine kinase 2-beta (Pyk2) are highly versatile multidomain scaffolds central to cell adhesion, migration, and survival. Due to their key role in cancer metastasis, understanding and inhibiting their functions are important for the development of targeted therapy. Because FAK and Pyk2 are involved in many different cellular functions, designing drugs with partial and function-specific inhibitory effects would be desirable. Here, we summarise recent progress in understanding the structural mechanism of how the tug-of-war between intramolecular and intermolecular interactions allows these protein ‘nanomachines’ to become activated in a site-specific manner.

  16. Abl tyrosine kinases modulate cadherin-dependent adhesion upstream and downstream of Rho family GTPases.

    Science.gov (United States)

    Zandy, Nicole L; Pendergast, Ann Marie

    2008-02-15

    Formation and dissolution of intercellular adhesions are processes of paramount importance during tissue morphogenesis and for pathological conditions such as tumor metastasis. Cadherin-mediated intercellular adhesion requires dynamic regulation of the actin cytoskeleton. The pathways that link cadherin signaling to cytoskeletal regulation remain poorly defined. We have recently uncovered a novel role for the Abl family of tyrosine kinases linking cadherin-mediated adhesion to actin dynamics via the regulation of Rho family GTPases. Abl kinases are activated by cadherin engagement, localize to cell-cell junctions and are required for the formation of adherens junctions. Notably, we showed that Abl kinases are required for Rac activation during formation of adherens junctions, and also regulate a Rho-ROCK-myosin signaling pathway that is required for the maintenance of intercellular adhesion. Here we show that Abl kinases regulate the formation and strengthening of adherens junctions downstream of active Rac, and that Abl tyrosine kinases are components of a positive feed-back loop that employs the Crk/CrkL adaptor proteins to promote the formation and maturation of adherens junctions.

  17. Copper deficiency induced emphysema is associated with focal adhesion kinase inactivation.

    Directory of Open Access Journals (Sweden)

    Shiro Mizuno

    Full Text Available BACKGROUND: Copper is an important regulator of hypoxia inducible factor 1 alpha (HIF-1α dependent vascular endothelial growth factor (VEGF expression, and is also required for the activity of lysyl oxidase (LOX to effect matrix protein cross-linking. Cell detachment from the extracellular matrix can induce apoptosis (anoikis via inactivation of focal adhesion kinase (FAK. METHODOLOGY: To examine the molecular mechanisms whereby copper depletion causes the destruction of the normal alveolar architecture via anoikis, Male Sprague-Dawley rats were fed a copper deficient diet for 6 weeks while being treated with the copper chelator, tetrathiomolybdate. Other groups of rats were treated with the inhibitor of auto-phosphorylation of FAK, 1,2,4,5-benzenetetraamine tetrahydrochloride (1,2,4,5-BT or FAK small interfering RNA (siRNA. PRINCIPAL FINDINGS: Copper depletion caused emphysematous changes, decreased HIF-1α activity, and downregulated VEGF expression in the rat lungs. Cleaved caspase-3, caspase-8 and Bcl-2 interacting mediator of cell death (Bim expression was increased, and the phosphorylation of FAK was decreased in copper depleted rat lungs. Administration of 1,2,4,5-BT and FAK siRNA caused emphysematous lung destruction associated with increased expression of cleaved capase-3, caspase-8 and Bim. CONCLUSIONS: These data indicate that copper-dependent mechanisms contribute to the pathogenesis of emphysema, which may be associated with decreased HIF-1α and FAK activity in the lung.

  18. FAK dimerization controls its kinase-dependent functions at focal adhesions

    KAUST Repository

    Brami-Cherrier, Karen

    2014-01-30

    Focal adhesion kinase (FAK) controls adhesion-dependent cell motility, survival, and proliferation. FAK has kinase-dependent and kinase-independent functions, both of which play major roles in embryogenesis and tumor invasiveness. The precise mechanisms of FAK activation are not known. Using x-ray crystallography, small angle x-ray scattering, and biochemical and functional analyses, we show that the key step for activation of FAK\\'s kinase-dependent functions-autophosphorylation of tyrosine-397-requires site-specific dimerization of FAK. The dimers form via the association of the N-terminal FERM domain of FAK and are stabilized by an interaction between FERM and the C-terminal FAT domain. FAT binds to a basic motif on FERM that regulates co-activation and nuclear localization. FAK dimerization requires local enrichment, which occurs specifically at focal adhesions. Paxillin plays a dual role, by recruiting FAK to focal adhesions and by reinforcing the FAT:FERM interaction. Our results provide a structural and mechanistic framework to explain how FAK combines multiple stimuli into a site-specific function. The dimer interfaces we describe are promising targets for blocking FAK activation. © 2014 The Authors.

  19. Focal adhesion kinase regulates pathogen-killing capability and life span of neutrophils via mediating both adhesion-dependent and -independent cellular signals.

    Science.gov (United States)

    Kasorn, Anongnard; Alcaide, Pilar; Jia, Yonghui; Subramanian, Kulandayan K; Sarraj, Bara; Li, Yitang; Loison, Fabien; Hattori, Hidenori; Silberstein, Leslie E; Luscinskas, William F; Luo, Hongbo R

    2009-07-15

    Various neutrophil functions such as phagocytosis, superoxide production, and survival are regulated by integrin signaling. Despite the essential role of focal adhesion kinase (FAK) in mediating this signaling pathway, its exact function in neutrophils is ill defined. In this study, we investigated the role of FAK in neutrophils using a myeloid-specific conditional FAK knockout mouse. As reported in many other cell types, FAK is required for regulation of focal adhesion dynamics when neutrophils adhere to fibronectin or ICAM-1. Adhesion on VCAM-1-coated surfaces and chemotaxis after adhesion were not altered in FAK null neutrophils. In addition, we observed significant reduction in NADPH oxidase-mediated superoxide production and complement-mediated phagocytosis in FAK null neutrophils. As a result, these neutrophils displayed decreased pathogen killing capability both in vitro and in vivo in a mouse peritonitis model. In adherent cells, the defects associated with FAK deficiency are likely due to suppression of phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) signaling and chemoattractant-elicited calcium signaling. Disruption of FAK also reduced chemoattractant-elicited superoxide production in suspended neutrophils in the absence of cell adhesion. This may be solely caused by suppression of PtdIns(3,4,5)P3 signaling in these cells, because the fMLP-elicited calcium signal was not altered. Consistent with decreased PtdIns(3,4,5)P3/Akt signaling in FAK null neutrophils, we also observed accelerated spontaneous death in these cells. Taken together, our results revealed previously unrecognized roles of FAK in neutrophil function and provided a potential therapeutic target for treatment of a variety of infectious and inflammatory diseases.

  20. Focal adhesion kinase regulates expression of thioredoxin-interacting protein (TXNIP) in cancer cells.

    Science.gov (United States)

    Ho, Baotran; Huang, Grace; Golubovskaya, Vita M

    2014-01-01

    Focal Adhesion Kinase (FAK) plays an important role in cancer cell survival. Previous microarray gene profiling study detected inverse regulation between expression of thioredoxin-interacting protein (TXNIP) and FAK, where down-regulation of FAK by siRNA in MCF-7 cells caused up-regulation of TXNIP mRNA level, and in contrast up-regulation of doxycyclin- induced FAK caused repression of TXNIP. In the present report, we show that overexpression of FAK in MCF-7 cells repressed TXNIP promoter activity. Treatment of MCF-7 cells with 1alpha, 25-dihydroxyvitamin D3 (1,25D) down-regulated endogenous FAK and up-regulated TXNIP protein level, and treatment with 5-FU decreased FAK protein expression and up-regulated TXNIP protein expression in 293 cells. Moreover, silencing of FAK with siRNA increased TXNIP protein expression, while overexpression of FAK inhibited TXNIP protein expression in 293 cells. In addition, treatment of DBTRG glioblastoma cells with FAK inhibitor Y15 increased TXNIP mRNA, decreased cancer cell viability and increased apoptosis. These results for the first time demonstrate FAK-regulated TXNIP expression which is important for apoptotic, survival and oxidative stress signaling pathways in cancer cells.

  1. Targeting Protein Kinase C Downstream of Growth Factor and Adhesion Signalling

    Directory of Open Access Journals (Sweden)

    Catríona M. Dowling

    2015-07-01

    Full Text Available The signaling outputs of Receptor Tyrosine Kinases, G-protein coupled receptors and integrins converge to mediate key cell process such as cell adhesion, cell migration, cell invasion and cell proliferation. Once activated by their ligands, these cell surface proteins recruit and direct a diverse range of proteins to disseminate the appropriate response downstream of the specific environmental cues. One of the key groups of proteins required to regulate these activities is the family of serine/threonine intracellular kinases called Protein Kinase Cs. The activity and subcellular location of PKCs are mediated by a series of tightly regulated events and is dependent on several posttranslational modifications and the availability of second messengers. Protein Kinase Cs exhibit both pro- and anti-tumorigenic effects making them an interesting target for anti-cancer treatment.

  2. Targeting Protein Kinase C Downstream of Growth Factor and Adhesion Signalling

    Energy Technology Data Exchange (ETDEWEB)

    Dowling, Catríona M., E-mail: Catriona.Dowling@ul.ie; Kiely, Patrick A., E-mail: Catriona.Dowling@ul.ie [Department of Life Sciences, Materials and Surface Science Institute and Stokes Institute, University of Limerick, Limerick 78666 (Ireland); Health Research Institute (HRI), University of Limerick, Limerick 78666 (Ireland)

    2015-07-15

    The signaling outputs of Receptor Tyrosine Kinases, G-protein coupled receptors and integrins converge to mediate key cell process such as cell adhesion, cell migration, cell invasion and cell proliferation. Once activated by their ligands, these cell surface proteins recruit and direct a diverse range of proteins to disseminate the appropriate response downstream of the specific environmental cues. One of the key groups of proteins required to regulate these activities is the family of serine/threonine intracellular kinases called Protein Kinase Cs. The activity and subcellular location of PKCs are mediated by a series of tightly regulated events and is dependent on several posttranslational modifications and the availability of second messengers. Protein Kinase Cs exhibit both pro- and anti-tumorigenic effects making them an interesting target for anti-cancer treatment.

  3. Polyclonal neural cell adhesion molecule antibody prolongs the effective duration time of botulinum toxin in decreasing muscle strength.

    Science.gov (United States)

    Guo, Yan; Pan, Lizhen; Liu, Wuchao; Pan, Yougui; Nie, Zhiyu; Jin, Lingjing

    2015-11-01

    This study aimed to investigate if the effective duration time of botulinum toxin A (Btx-A) could be prolonged by polyclonal neural cell adhesion molecule antibody (P-NCAM-Ab). 175 male SD rats were randomly divided into three major groups: control group (n = 25), Btx-A group (n = 25), and P-NCAM-Ab groups. P-NCAM-Ab groups were composed of five sub-groups, with 25 rats each in the dose-response study. Muscle strength of rat lower limbs was determined using a survey system. The expressions of muscle-specific receptor tyrosine kinase (MuSK) and neural cell adhesion molecule (NCAM) were determined by real-time polymerase chain reactions (RT-PCR) and western blotting (WB). The muscle strength was significantly decreased by Btx-A in Btx-A/P-NCAM-Ab groups compared with normal control group. Besides, the muscle strength of P-NCAM-Ab group was significantly decreased compared with the Btx-A group. The recovery time of muscle strength in P-NCAM-Ab group was significantly longer compared with Btx-A group. RT-PCR and WB assay showed that PNCAM-Ab delayed the increase of MuSK and NCAM after Btx-A injection. P-NCAM-Ab prolongs the effective duration time of Btx-A in decreasing muscle strength, which could provide a novel enhancement in clinical application.

  4. Integrin-linked kinase regulates oligodendrocyte cytoskeleton, growth cone, and adhesion dynamics.

    Science.gov (United States)

    Michalski, John-Paul; Cummings, Sarah E; O'Meara, Ryan W; Kothary, Rashmi

    2016-02-01

    Integrin-linked kinase (ILK), a focal adhesion protein, brokers the link between cytoskeleton, cell membrane, and extracellular environment. Here, we demonstrate a role for ILK in laminin-2-mediated adhesion in primary murine oligodendrocytes (OLs) - with ILK loss leading to severe defects in process branching and outgrowth. These defects were partially recovered when the ILK-depleted OLs were instead grown on the non-integrin-activating substrate poly-l-lysine. Intriguingly, ILK loss on the neutral poly-l-lysine substrate led to swelling at the tips of OL processes, which we identified as enlarged growth cones. Employing the bloated ILK-depleted growth cones as template, we demonstrate the appearance of distinct cytoskeletal domains within OL growth cones bearing classic neuronal growth cone architecture. Further, microtubule organization was severely perturbed following ILK loss, with centripetal microtubule looping and failure to bundle occurring in a laminin-2-independent manner. Together, our work highlights differences in specific aspects of OL biology as driven by laminin-2-dependent or independent ILK governed mechanisms. We also reinforce the idea of OLs as growth cone bearing cells and describe the neuronal-like cytoskeleton therein. Finally, we demonstrate a role for ILK in OL growth cone maturation through microtubule regulation, the loss of which translates to decreased process length and myelin production capacity. We describe herein how different substrates fundamentally alter the oligodendrocyte's response to loss of integrin-linked kinase (ILK). On laminin-2 (Ln-2), ILK-depleted oligodendrocytes appear stunted and malformed, while on the non-integrin-activating substrate PLL branching and membrane formation are restored. We also reinforce the idea of oligodendrocytes as growth cone-bearing cells, detailing the growth cone's cytoskeletal architecture. Strikingly, loss of ILK on poly-l-lysine leads to growth cone swelling, the structure's size and

  5. Focal adhesion kinase is required for actin polymerization and remodeling of the cytoskeleton during sperm capacitation

    Science.gov (United States)

    Roa-Espitia, Ana L.; Hernández-Rendón, Eva R.; Baltiérrez-Hoyos, Rafael; Muñoz-Gotera, Rafaela J.; Cote-Vélez, Antonieta; Jiménez, Irma; González-Márquez, Humberto

    2016-01-01

    ABSTRACT Several focal adhesion proteins are known to cooperate with integrins to link the extracellular matrix to the actin cytoskeleton; as a result, many intracellular signaling pathways are activated and several focal adhesion complexes are formed. However, how these proteins function in mammalian spermatozoa remains unknown. We confirm the presence of focal adhesion proteins in guinea pig spermatozoa, and we explore their role during capacitation and the acrosome reaction, and their relationship with the actin cytoskeleton. Our results suggest the presence of a focal adhesion complex formed by β1-integrin, focal adhesion kinase (FAK), paxillin, vinculin, talin, and α-actinin in the acrosomal region. Inhibition of FAK during capacitation affected the protein tyrosine phosphorylation associated with capacitation that occurs within the first few minutes of capacitation, which caused the acrosome reaction to become increasingly Ca2+ dependent and inhibited the polymerization of actin. The integration of vinculin and talin into the complex, and the activation of FAK and paxillin during capacitation, suggests that the complex assembles at this time. We identify that vinculin and α-actinin increase their interaction with F-actin while it remodels during capacitation, and that during capacitation focal adhesion complexes are structured. FAK contributes to acrosome integrity, likely by regulating the polymerization and the remodeling of the actin cytoskeleton. PMID:27402964

  6. Increased Mesenchymal Stem Cell Response and Decreased Staphylococcus aureus Adhesion on Titania Nanotubes without Pharmaceuticals

    Science.gov (United States)

    Xu, Zhiqiang; Lai, Yingzhen; Wu, Dong; Huang, Wenxiu; Huang, Sijia; Zhou, Lin; Chen, Jiang

    2015-01-01

    Titanium (Ti) implants with enhanced biocompatibility and antibacterial property are highly desirable and characterized by improved success rates. In this study, titania nanotubes (TNTs) with various tube diameters were fabricated on Ti surfaces through electrochemical anodization at 10, 30, and 60 V (denoted as NT10, NT30, and NT60, resp.). Ti was also investigated and used as a control. NT10 with a diameter of 30 nm could promote the adhesion and proliferation of bone marrow mesenchymal stem cells (BMSCs) without noticeable differentiation. NT30 with a diameter of 100 nm could support the adhesion and proliferation of BMSCs and induce osteogenesis. NT60 with a diameter of 200 nm demonstrated the best ability to promote cell spreading and osteogenic differentiation; however, it clearly impaired cell adhesion and proliferation. As the tube diameter increased, bacterial adhesion on the TNTs decreased and reached the lowest value on NT60. Therefore, NT30 without pharmaceuticals could be used to increase mesenchymal stem cell response and decrease Staphylococcus aureus adhesion and thus should be further studied for improving the efficacy of Ti-based orthopedic implants. PMID:26640782

  7. Fluid-flow-induced mesenchymal stem cell migration: role of focal adhesion kinase and RhoA kinase sensors.

    Science.gov (United States)

    Riehl, Brandon D; Lee, Jeong Soon; Ha, Ligyeom; Lim, Jung Yul

    2015-03-01

    The study of mesenchymal stem cell (MSC) migration under flow conditions with investigation of the underlying molecular mechanism could lead to a better understanding and outcome in stem-cell-based cell therapy and regenerative medicine. We used peer-reviewed open source software to develop methods for efficiently and accurately tracking, measuring and processing cell migration as well as morphology. Using these tools, we investigated MSC migration under flow-induced shear and tested the molecular mechanism with stable knockdown of focal adhesion kinase (FAK) and RhoA kinase (ROCK). Under steady flow, MSCs migrated following the flow direction in a shear stress magnitude-dependent manner, as assessed by root mean square displacement and mean square displacement, motility coefficient and confinement ratio. Silencing FAK in MSCs suppressed morphology adaptation capability and reduced cellular motility for both static and flow conditions. Interestingly, ROCK silencing significantly increased migration tendency especially under flow. Blocking ROCK, which is known to reduce cytoskeletal tension, may lower the resistance to skeletal remodelling during the flow-induced migration. Our data thus propose a potentially differential role of focal adhesion and cytoskeletal tension signalling elements in MSC migration under flow shear.

  8. The role of phosphatidylinositol 3-kinase in neural cell adhesion molecule-mediated neuronal differentiation and survival

    DEFF Research Database (Denmark)

    Ditlevsen, Dorte K; Køhler, Lene B; Pedersen, Martin Volmer;

    2003-01-01

    The neural cell adhesion molecule, NCAM, is known to stimulate neurite outgrowth from primary neurones and PC12 cells presumably through signalling pathways involving the fibroblast growth factor receptor (FGFR), protein kinase A (PKA), protein kinase C (PKC), the Ras-mitogen activated protein...

  9. The role of phosphatidylinositol 3-kinase in neural cell adhesion molecule-mediated neuronal differentiation and survival

    DEFF Research Database (Denmark)

    Ditlevsen, Dorte K; Køhler, Lene B; Pedersen, Martin V

    2003-01-01

    The neural cell adhesion molecule, NCAM, is known to stimulate neurite outgrowth from primary neurones and PC12 cells presumably through signalling pathways involving the fibroblast growth factor receptor (FGFR), protein kinase A (PKA), protein kinase C (PKC), the Ras-mitogen activated protein ki...

  10. Subinhibitory Concentrations of Allicin Decrease Uropathogenic Escherichia coli (UPEC) Biofilm Formation, Adhesion Ability, and Swimming Motility.

    Science.gov (United States)

    Yang, Xiaolong; Sha, Kaihui; Xu, Guangya; Tian, Hanwen; Wang, Xiaoying; Chen, Shanze; Wang, Yi; Li, Jingyu; Chen, Junli; Huang, Ning

    2016-06-29

    Uropathogenic Escherichia coli (UPEC) biofilm formation enables the organism to avoid the host immune system, resist antibiotics, and provide a reservoir for persistent infection. Once the biofilm is established, eradication of the infection becomes difficult. Therefore, strategies against UPEC biofilm are urgently required. In this study, we investigated the effect of allicin, isolated from garlic essential oil, on UPEC CFT073 and J96 biofilm formation and dispersal, along with its effect on UPEC adhesion ability and swimming motility. Sub-inhibitory concentrations (sub-MICs) of allicin decreased UPEC biofilm formation and affected its architecture. Allicin was also capable of dispersing biofilm. Furthermore, allicin decreased the bacterial adhesion ability and swimming motility, which are important for biofilm formation. Real-time quantitative polymerase chain reaction (RT-qPCR) revealed that allicin decreased the expression of UPEC type 1 fimbriae adhesin gene fimH. Docking studies suggested that allicin was located within the binding pocket of heptyl α-d-mannopyrannoside in FimH and formed hydrogen bonds with Phe1 and Asn135. In addition, allicin decreased the expression of the two-component regulatory systems (TCSs) cognate response regulator gene uvrY and increased the expression of the RNA binding global regulatory protein gene csrA of UPEC CFT073, which is associated with UPEC biofilm. The findings suggest that sub-MICs of allicin are capable of affecting UPEC biofilm formation and dispersal, and decreasing UPEC adhesion ability and swimming motility.

  11. Therapeutic effects of tyroservatide on metastasis of lung cancer and its mechanism affecting integrin–focal adhesion kinase signal transduction

    Science.gov (United States)

    Huang, Yu-ting; Zhao, Lan; Fu, Zheng; Zhao, Meng; Song, Xiao-meng; Jia, Jing; Wang, Song; Li, Jin-ping; Zhu, Zhi-feng; Lin, Gang; Lu, Rong; Yao, Zhi

    2016-01-01

    Tyroservatide (YSV) can inhibit the growth and metastasis of mouse lung cancer significantly. This study investigated the therapeutic effects of tripeptide YSV on metastasis of human lung cancer cells and explored its possible mechanism that affects integrin–focal adhesion kinase (FAK) signal transduction in tumor cells. YSV significantly inhibited the adhesion and the invasion of highly metastatic human lung cancer cell lines 95D, A549, and NCI-H1299. In addition, YSV significantly inhibited phosphorylation of FAK Tyr397 and FAK Tyr576/577 in the 95D, A549, and NCI-H1299 human lung cancer cells in vitro. And the mRNA level and protein expression of FAK in these human lung cancer cells decreased at the same time. YSV also significantly inhibited mRNA and protein levels of integrin β1 and integrin β3 in the 95D, A549, and NCI-H1299 human lung cancer cells. Our research showed that YSV inhibited adhesion and invasion of human lung cancer cells and exhibited therapeutic effects on metastasis of lung cancer. PMID:27041993

  12. Conformational Dynamics of the Focal Adhesion Targeting Domain Control Specific Functions of Focal Adhesion Kinase in Cells

    KAUST Repository

    Kadaré, Gress

    2015-01-02

    Focal adhesion (FA) kinase (FAK) regulates cell survival and motility by transducing signals from membrane receptors. The C-terminal FA targeting (FAT) domain of FAK fulfils multiple functions, including recruitment to FAs through paxillin binding. Phosphorylation of FAT on Tyr925 facilitates FA disassembly and connects to the MAPK pathway through Grb2 association, but requires dissociation of the first helix (H1) of the four-helix bundle of FAT. We investigated the importance of H1 opening in cells by comparing the properties of FAK molecules containing wild-type or mutated FAT with impaired or facilitated H1 openings. These mutations did not alter the activation of FAK, but selectively affected its cellular functions, including self-association, Tyr925 phosphorylation, paxillin binding, and FA targeting and turnover. Phosphorylation of Tyr861, located between the kinase and FAT domains, was also enhanced by the mutation that opened the FAT bundle. Similarly phosphorylation of Ser910 by ERK in response to bombesin was increased by FAT opening. Although FAK molecules with the mutation favoring FAT opening were poorly recruited at FAs, they efficiently restored FA turnover and cell shape in FAK-deficient cells. In contrast, the mutation preventing H1 opening markedly impaired FAK function. Our data support the biological importance of conformational dynamics of the FAT domain and its functional interactions with other parts of the molecule.

  13. Role of Cbl-associated protein/ponsin in receptor tyrosine kinase signaling and cell adhesion

    Directory of Open Access Journals (Sweden)

    Ritva Tikkanen

    2012-10-01

    Full Text Available The Cbl-associated protein/ponsin (CAP is an adaptor protein that contains a so-called Sorbin homology (SoHo domain and three Src homology 3 (SH3 domains which are engaged in diverse protein-protein interactions. CAP has been shown to function in the regulation of the actin cytoskeleton and cell adhesion and to be involved in the differentiation of muscle cells and adipocytes. In addition, it participates in signaling pathways through several receptor tyrosine kinases such as insulin and neurotrophin receptors. In the last couple of years, several studies have shed light on the details of these processes and identified novel interaction partners of CAP. In this review, we summarize these recent findings and provide an overview on the function of CAP especially in cell adhesion and membrane receptor signaling.

  14. Focal Adhesion Kinase Regulates Expression of Thioredoxin-interacting Protein (TXNIP) in Cancer Cells

    OpenAIRE

    2014-01-01

    Focal Adhesion Kinase (FAK) plays an important role in cancer cell survival. Previous microarray gene profiling study detected inverse regulation between expression of thioredoxin-interacting protein (TXNIP) and FAK, where down-regulation of FAK by siRNA in MCF-7 cells caused up-regulation of TXNIP mRNA level, and in contrast up-regulation of doxycyclin- induced FAK caused repression of TXNIP. In the present report, we show that overexpression of FAK in MCF-7 cells repressed TXNIP promoter ac...

  15. Focal adhesion kinase modulates activation of NF-κB by flow in endothelial cells

    OpenAIRE

    Petzold, Tobias; Orr, A. Wayne; Hahn, Cornelia; Jhaveri, Krishna A.; Parsons, J Thomas; Schwartz, Martin Alexander

    2009-01-01

    Atherogenesis involves activation of NF-κB in endothelial cells by fluid shear stress. Because this pathway involves integrins, we investigated the involvement of focal adhesion kinase (FAK). We found that FAK was not required for flow-stimulated translocation of the p65 NF-κB subunit to the nucleus but was essential for phosphorylation of p65 on serine 536 and induction of ICAM-1, an NF-κB-dependent gene. NF-κB activation by TNF-α or hydrogen peroxide was FAK independent. Events upstream of ...

  16. Inhibition of Focal Adhesion Kinase (FAK) Leads to Abrogation of the Malignant Phenotype in Aggressive Pediatric Renal Malignancies

    Science.gov (United States)

    Megison, Michael L.; Gillory, Lauren A.; Stewart, Jerry E.; Nabers, Hugh C.; Mrozcek-Musulman, Elizabeth; Beierle, Elizabeth A.

    2014-01-01

    Despite the tremendous advances in the treatment of childhood kidney tumors, there remain subsets of pediatric renal tumors that continue to pose a therapeutic challenge, mainly malignant rhabdoid kidney tumors and non-osseous renal Ewing sarcoma. Children with advanced, metastatic or relapsed disease have a disease-free survival rate under 30%. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumor development and progression. FAK has been found in other pediatric solid tumors and in adult renal cellular carcinoma, leading us to hypothesize that FAK would be present in pediatric kidney tumors and would impact their cellular survival. In the current study, we showed that FAK was present and phosphorylated in pediatric kidney tumor specimens. We also examined the effects of FAK inhibition upon G401 and SK-NEP-1 cell lines utilizing a number of parallel approaches to block FAK including RNAi and small molecule FAK inhibitors. FAK inhibition resulted in decreased cellular survival, invasion and migration, and increased apoptosis. Further, small molecule inhibition of FAK led to decreased tumor growth in a nude mouse SK-NEP-1 xenograft model. The findings from this study will help to further our understanding of the regulation of tumorigenesis in rare pediatric renal tumors, and may provide desperately needed novel therapeutic strategies and targets for these rare, but difficult to treat, malignancies. PMID:24464916

  17. Mycosporine-Like Amino Acids Promote Wound Healing through Focal Adhesion Kinase (FAK and Mitogen-Activated Protein Kinases (MAP Kinases Signaling Pathway in Keratinocytes

    Directory of Open Access Journals (Sweden)

    Yun-Hee Choi

    2015-11-01

    Full Text Available Mycosporine-like amino acids (MAAs are secondary metabolites found in diverse marine, freshwater, and terrestrial organisms. Evidence suggests that MAAs have several beneficial effects on skin homeostasis such as protection against UV radiation and reactive oxygen species (ROS. In addition, MAAs are also involved in the modulation of skin fibroblasts proliferation. However, the regulatory function of MAAs on wound repair in human skin is not yet clearly elucidated. To investigate the roles of MAAs on the wound healing process in human keratinocytes, three MAAs, Shinorine (SH, Mycosporine-glycine (M-Gly, and Porphyra (P334 were purified from Chlamydomonas hedlyei and Porphyra yezoensis. We found that SH, M-Gly, and P334 have significant effects on the wound healing process in human keratinocytes and these effects were mediated by activation of focal adhesion kinases (FAK, extracellular signal-regulated kinases (ERK, and c-Jun N-terminal kinases (JNK. These results suggest that MAAs accelerate wound repair by activating the FAK-MAPK signaling pathways. This study also indicates that MAAs can act as a new wound healing agent and further suggests that MAAs might be a novel biomaterial for wound healing therapies.

  18. Integrin-Associated Focal Adhesion Kinase Protects Human Embryonic Stem Cells from Apoptosis, Detachment, and Differentiation

    Directory of Open Access Journals (Sweden)

    Loriana Vitillo

    2016-08-01

    Full Text Available Human embryonic stem cells (hESCs can be maintained in a fully defined niche on extracellular matrix substrates, to which they attach through integrin receptors. However, the underlying integrin signaling mechanisms, and their contribution to hESC behavior, are largely unknown. Here, we show that focal adhesion kinase (FAK transduces integrin activation and supports hESC survival, substrate adhesion, and maintenance of the undifferentiated state. After inhibiting FAK kinase activity we show that hESCs undergo cell detachment-dependent apoptosis or differentiation. We also report deactivation of FAK downstream targets, AKT and MDM2, and upregulation of p53, all key players in hESC regulatory networks. Loss of integrin activity or FAK also induces cell aggregation, revealing a role in the cell-cell interactions of hESCs. This study provides insight into the integrin signaling cascade activated in hESCs and reveals in FAK a key player in the maintenance of hESC survival and undifferentiated state.

  19. Focal adhesion kinase modulates radial glia-dependent neuronal migration through connexin-26.

    Science.gov (United States)

    Valiente, Manuel; Ciceri, Gabriele; Rico, Beatriz; Marín, Oscar

    2011-08-10

    Focal adhesion kinase (FAK) is an intracellular kinase and scaffold protein that regulates migration in many different cellular contexts but whose function in neuronal migration remains controversial. Here, we have analyzed the function of FAK in two populations of neurons with very distinct migratory behaviors: cortical interneurons, which migrate tangentially and independently of radial glia; and pyramidal cells, which undergo glial-dependent migration. We found that FAK is dispensable for glial-independent migration but is cell-autonomously required for the normal interaction of pyramidal cells with radial glial fibers. Loss of FAK function disrupts the normal morphology of migrating pyramidal cells, delays migration, and increases the tangential dispersion of neurons arising from the same radial unit. FAK mediates this process by regulating the assembly of Connexin-26 contact points in the membrane of migrating pyramidal cells. These results indicate that FAK plays a fundamental role in the dynamic regulation of Gap-mediated adhesions during glial-guided neuronal migration in the mouse.

  20. Distinct biophysical mechanisms of focal adhesion kinase mechanoactivation by different extracellular matrix proteins.

    Science.gov (United States)

    Seong, Jihye; Tajik, Arash; Sun, Jie; Guan, Jun-Lin; Humphries, Martin J; Craig, Susan E; Shekaran, Asha; García, Andrés J; Lu, Shaoying; Lin, Michael Z; Wang, Ning; Wang, Yingxiao

    2013-11-26

    Matrix mechanics controls cell fate by modulating the bonds between integrins and extracellular matrix (ECM) proteins. However, it remains unclear how fibronectin (FN), type 1 collagen, and their receptor integrin subtypes distinctly control force transmission to regulate focal adhesion kinase (FAK) activity, a crucial molecular signal governing cell adhesion/migration. Here we showed, using a genetically encoded FAK biosensor based on fluorescence resonance energy transfer, that FN-mediated FAK activation is dependent on the mechanical tension, which may expose its otherwise hidden FN synergy site to integrin α5. In sharp contrast, the ligation between the constitutively exposed binding motif of type 1 collagen and its receptor integrin α2 was surprisingly tension-independent to induce sufficient FAK activation. Although integrin α subunit determines mechanosensitivity, the ligation between α subunit and the ECM proteins converges at the integrin β1 activation to induce FAK activation. We further discovered that the interaction of the N-terminal protein 4.1/ezrin/redixin/moesin basic patch with phosphatidylinositol 4,5-biphosphate is crucial during cell adhesion to maintain the FAK activation from the inhibitory effect of nearby protein 4.1/ezrin/redixin/moesin acidic sites. Therefore, different ECM proteins either can transmit or can shield from mechanical forces to regulate cellular functions, with the accessibility of ECM binding motifs by their specific integrin α subunits determining the biophysical mechanisms of FAK activation during mechanotransduction.

  1. Protective influence of hyaluronic acid on focal adhesion kinase activity in human skin fibroblasts exposed to ethanol

    Directory of Open Access Journals (Sweden)

    Donejko M

    2017-03-01

    Full Text Available Magdalena Donejko,1 Edyta Rysiak,2 Elżbieta Galicka,1 Robert Terlikowski,3 Edyta Katarzyna Głażewska,1 Andrzej Przylipiak1 1Department of Esthetic Medicine, 2Department of Medicinal Chemistry, Faculty of Pharmacy, 3Department of Health Restoration, Medical University of Białystok, Białystok, Poland Aim: The aim of this study was to evaluate the effect of ethanol and hyaluronic acid (HA on cell survival and apoptosis in cultured human skin fibroblasts. Regarding the mechanism of ethanol action on human skin fibroblasts, we investigated cell viability and apoptosis, expression of focal adhesion kinase (FAK, and the influence of HA on those processes. Materials and methods: Studies were conducted in confluent human skin fibroblast cultures that were treated with 25 mM, 50 mM, and 100 mM ethanol or with ethanol and 500 µg/mL HA. Cell viability was examined using methyl thiazolyl tetrazolium (MTT assay and NC-300 Nucleo-Counter. Imaging of the cells using a fluorescence microscope Pathway 855 was performed to measure FAK expression. Results: Depending on the dosage, ethanol decreased cell viability and activated the process of apoptosis in human skin fibroblasts. HA prevented the negative influence of ethanol on cell viability and prevented apoptosis. The analysis of fluorescence imaging using BD Pathway 855 High-Content Bioimager showed the inhibition of FAK migration to the cell nucleus, depending on the increasing concentration of ethanol. Conclusion: This study proves that downregulation of signaling pathway of FAK is involved in ethanol-induced apoptosis in human skin fibroblasts. The work also indicates a protective influence of HA on FAK activity in human skin fibroblasts exposed to ethanol. Keywords: apoptosis, skin fibroblast, focal adhesion kinase, hyaluronic acid, ethanol

  2. Hydrogen-Rich Medium Attenuated Lipopolysaccharide-Induced Monocyte-Endothelial Cell Adhesion and Vascular Endothelial Permeability via Rho-Associated Coiled-Coil Protein Kinase.

    Science.gov (United States)

    Xie, Keliang; Wang, Weina; Chen, Hongguang; Han, Huanzhi; Liu, Daquan; Wang, Guolin; Yu, Yonghao

    2015-07-01

    Sepsis is the leading cause of death in critically ill patients. In recent years, molecular hydrogen, as an effective free radical scavenger, has been shown a selective antioxidant and anti-inflammatory effect, and it is beneficial in the treatment of sepsis. Rho-associated coiled-coil protein kinase (ROCK) participates in junction between normal cells, and regulates vascular endothelial permeability. In this study, we used lipopolysaccharide to stimulate vascular endothelial cells and explored the effects of hydrogen-rich medium on the regulation of adhesion of monocytes to endothelial cells and vascular endothelial permeability. We found that hydrogen-rich medium could inhibit adhesion of monocytes to endothelial cells and decrease levels of adhesion molecules, whereas the levels of transepithelial/endothelial electrical resistance values and the expression of vascular endothelial cadherin were increased after hydrogen-rich medium treatment. Moreover, hydrogen-rich medium could lessen the expression of ROCK, as a similar effect of its inhibitor Y-27632. In addition, hydrogen-rich medium could also inhibit adhesion of polymorphonuclear neutrophils to endothelial cells. In conclusion, hydrogen-rich medium could regulate adhesion of monocytes/polymorphonuclear neutrophils to endothelial cells and vascular endothelial permeability, and this effect might be related to the decreased expression of ROCK protein.

  3. Plasmodium falciparum Choline Kinase Inhibition Leads to a Major Decrease in Phosphatidylethanolamine Causing Parasite Death

    Science.gov (United States)

    Serrán-Aguilera, Lucía; Denton, Helen; Rubio-Ruiz, Belén; López-Gutiérrez, Borja; Entrena, Antonio; Izquierdo, Luis; Smith, Terry K.; Conejo-García, Ana; Hurtado-Guerrero, Ramon

    2016-01-01

    Malaria is a life-threatening disease caused by different species of the protozoan parasite Plasmodium, with P. falciparum being the deadliest. Increasing parasitic resistance to existing antimalarials makes the necessity of novel avenues to treat this disease an urgent priority. The enzymes responsible for the synthesis of phosphatidylcholine and phosphatidylethanolamine are attractive drug targets to treat malaria as their selective inhibition leads to an arrest of the parasite’s growth and cures malaria in a mouse model. We present here a detailed study that reveals a mode of action for two P. falciparum choline kinase inhibitors both in vitro and in vivo. The compounds present distinct binding modes to the choline/ethanolamine-binding site of P. falciparum choline kinase, reflecting different types of inhibition. Strikingly, these compounds primarily inhibit the ethanolamine kinase activity of the P. falciparum choline kinase, leading to a severe decrease in the phosphatidylethanolamine levels within P. falciparum, which explains the resulting growth phenotype and the parasites death. These studies provide an understanding of the mode of action, and act as a springboard for continued antimalarial development efforts selectively targeting P. falciparum choline kinase. PMID:27616047

  4. Biphasic function of focal adhesion kinase in endothelial tube formation induced by fibril-forming collagens.

    Science.gov (United States)

    Nakamura, Junko; Shigematsu, Satoshi; Yamauchi, Keishi; Takeda, Teiji; Yamazaki, Masanori; Kakizawa, Tomoko; Hashizume, Kiyoshi

    2008-10-03

    Migration and tube formation of endothelial cells are important in angiogenesis and require a coordinated response to the extra-cellular matrix (ECM) and growth factor. Since focal adhesion kinase (FAK) integrates signals from both ECM and growth factor, we investigated its role in angiogenesis. Type I and II collagens are fibril-forming collagens and stimulate human umbilical vein endothelial cells (HUVECs) to form tube structure. Although knockdown of FAK restrained cell motility and resulted in inhibition of tube formation, FAK degradation and tube formation occurred simultaneously after incubation with fibril-forming collagens. The compensation for the FAK degradation by a calpain inhibitor or transient over-expression of FAK resulted in disturbance of tube formation. These phenomena are specific to fibril-forming collagens and mediated via alpha2beta1 integrin. In conclusion, our data indicate that FAK is functioning in cell migration, but fibril-forming collagen-induced FAK degradation is necessary for endothelial tube formation.

  5. Down-regulation of integrin β1 and focal adhesion kinase in renal glomeruli under various hemodynamic conditions.

    Directory of Open Access Journals (Sweden)

    Xiaoli Yuan

    Full Text Available Given that integrin β1 is an important component of the connection to maintain glomerular structural integrity, by binding with multiple extracellular matrix proteins and mediating intracellular signaling. Focal adhesion kinase (FAK is the most essential intracellular integrator in the integrin β1-FAK signalling pathway. Here, we investigated the changes of the two molecules and visualized the possible interaction between them under various hemodynamic conditions in podocytes. Mice kidney tissues were prepared using in vivo cryotechnique (IVCT and then were stained and observed using light microscopy, confocal laser scanning microscopy and immunoelectron microscopy. The expression of these molecules were examined by western blot. Under the normal condition, integrin β1 stained continually and evenly at the membrane, and FAK was located in the cytoplasm and nuclei of the podocytes. There were significant colocalized plaques of two molecules. But under acute hypertensive and cardiac arrest conditions, integrin β1 decreased and stained intermittently. Similarly, FAK decreased and appeared uneven. Additionally, FAK translocated to the nuclei of the podocytes. As a result, the colocalization of integrin β1 and FAK reduced obviously under these conditions. Western blot assay showed a consistent result with the immunostaining. Collectively, the abnormal redistribution and decreased expressions of integrin β1 and FAK are important molecular events in regulating the functions of podocytes under abnormal hemodynamic conditions. IVCT could offer considerable advantages for morphological analysis when researching renal diseases.

  6. Mammary gland-specific ablation of focal adhesion kinase reduces the incidence of p53-mediated mammary tumour formation.

    NARCIS (Netherlands)

    Miltenburg, van M.H.; Nimwegen, van M.J.; Tijdens, R.B.; Lalai, R.A.; Kuiper, R.; Klarenbeek, S.; Schouten, P.C.; Vries, de A.; Jonkers, J.M.M..; Water, van de B.

    2014-01-01

    BACKGROUND Elevated expression of focal adhesion kinase (FAK) occurs in numerous human cancers including colon-, cervix- and breast cancer. Although several studies have implicated FAK in mammary tumour formation induced by ectopic oncogene expression, evidence supporting a role for FAK in spontaneo

  7. PROLACTIN-INDUCED TYROSINE PHOSPHORYLATION, ACTIVATION AND RECEPTOR ASSOCIATION OF FOCAL ADHESION KINASE (FAK) IN MAMMARY EPITHELIAL CELLS

    Science.gov (United States)

    Prolactin-Induced Tyrosine Phosphorylation, Activation and ReceptorAssociation of Focal Adhesion Kinase (FAK) in Mammary Epithelial Cells. Suzanne E. Fenton1 and Lewis G. Sheffield2. 1U.S. Environmental ProtectionAgency, MD-72, Research Triangle Park, NC 27711, and

  8. Decreased pulmonary inflammation after ethanol exposure and burn injury in intercellular adhesion molecule-1 knockout mice.

    Science.gov (United States)

    Bird, Melanie D; Morgan, Michelle O; Ramirez, Luis; Yong, Sherri; Kovacs, Elizabeth J

    2010-01-01

    Clinical and laboratory evidence suggests that alcohol consumption dysregulates immune function. Burn patients who consume alcohol before their injuries demonstrate higher rates of morbidity and mortality, including acute respiratory distress syndrome, than patients without alcohol at the time of injury. Our laboratory observed higher levels of proinflammatory cytokines and leukocyte infiltration in the lungs of mice after ethanol exposure and burn injury than with either insult alone. To understand the mechanism of the increased pulmonary inflammatory response in mice treated with ethanol and burn injury, we investigated the role of intercellular adhesion molecule (ICAM)-1. Wild-type and ICAM-1 knockout (KO) mice were treated with vehicle or ethanol and subsequently given a sham or burn injury. Twenty-four hours postinjury, lungs were harvested and analyzed for indices of inflammation. Higher numbers of neutrophils were observed in the lungs of wild-type mice after burn and burn with ethanol treatment. This increase in pulmonary inflammatory cell accumulation was significantly lower in the KO mice. In addition, levels of KC, interleukin-1beta, and interleukin-6 in the lung were decreased in the ICAM-1 KO mice after ethanol exposure and burn injury. Interestingly, no differences were observed in serum or lung tissue content of soluble ICAM-1 24 hours postinjury. These data suggest that upregulation of adhesion molecules such as ICAM-1 on the vascular endothelium may play a critical role in the excessive inflammation seen after ethanol exposure and burn injury.

  9. The role of focal adhesion kinase in the regulation of cellular mechanical properties

    Science.gov (United States)

    Mierke, Claudia Tanja

    2013-12-01

    The regulation of mechanical properties is necessary for cell invasion into connective tissue or intra- and extravasation through the endothelium of blood or lymph vessels. Cell invasion is important for the regulation of many healthy processes such as immune response reactions and wound healing. In addition, cell invasion plays a role in disease-related processes such as tumor metastasis and autoimmune responses. Until now the role of focal adhesion kinase (FAK) in regulating mechanical properties of cells and its impact on cell invasion efficiency is still not well known. Thus, this review focuses on mechanical properties regulated by FAK in comparison to the mechano-regulating protein vinculin. Moreover, it points out the connection between cancer cell invasion and metastasis and FAK by showing that FAK regulates cellular mechanical properties required for cellular motility. Furthermore, it sheds light on the indirect interaction of FAK with vinculin by binding to paxillin, which then impairs the binding of paxillin to vinculin. In addition, this review emphasizes whether FAK fulfills regulatory functions similar to vinculin. In particular, it discusses the differences and the similarities between FAK and vinculin in regulating the biomechanical properties of cells. Finally, this paper highlights that both focal adhesion proteins, vinculin and FAK, synergize their functions to regulate the mechanical properties of cells such as stiffness and contractile forces. Subsequently, these mechanical properties determine cellular invasiveness into tissues and provide a source sink for future drug developments to inhibit excessive cell invasion and hence, metastases formation.

  10. Apigenin Attenuates Melanoma Cell Migration by Inducing Anoikis through Integrin and Focal Adhesion Kinase Inhibition.

    Science.gov (United States)

    Hasnat, Md Abul; Pervin, Mehnaz; Lim, Ji Hong; Lim, Beong Ou

    2015-11-27

    Apigenin, a nonmutagenic flavonoid, has been found to have antitumor properties and is therefore particularly relevant for the development of chemotherapeutic agents for cancers. In this study, time- and dose-dependent cell viability and cytotoxicity were assessed to determine the effects of apigenin on A2058 and A375 melanoma cells. Melanoma cells were pretreated with different concentrations of apigenin and analyzed for morphological changes, anoikis induction, cell migration, and levels of proteins associated with apoptosis. Apigenin reduced integrin protein levels and inhibited the phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK1/2), which induce anoikis in human cutaneous melanoma cells. Apigenin exhibited dose-dependent inhibition of melanoma cell migration, unlike untreated controls. Furthermore, apigenin treatment increased apoptotic factors such as caspase-3 and cleaved poly(ADP-ribose) polymerase in a dose-dependent manner, demonstrating the metastasis of melanoma cells. Our results provide a new insight into the mechanisms by which apigenin prevents melanoma metastasis by sensitizing anoikis induced by the loss of integrin proteins in the FAK/ERK1/2 signaling pathway. These findings elucidate the related mechanisms and suggest the potential of apigenin in developing clinical treatment strategies against malignant melanoma.

  11. MicroRNA-7 regulates glioblastoma cell invasion via targeting focal adhesion kinase expression

    Institute of Scientific and Technical Information of China (English)

    WU De-gang; WANG Xi-rui; YOU Yong-ping; LIU Ning; WANG Ying-yi; FAN Li-gang; LUO Hui; HAN Bin; SUN Li-hua; WANG Xie-feng; ZHANG Jun-xia; CAO Lei

    2011-01-01

    Background Invasion growth is the most characteristic biological phenotype of glioblastoma,but the molecular mechanism in glioma cell invasion is poorly understood.Recent data have showed that microRNA plays an essential role in tumor invasion.Our study aimed to explore the mechanism of miR-7 involved in the control of glioblastoma cell invasion.Methods Glioma cell invasion was evaluated by transwell and scratch assays after up-regulation of miR-7 using miR-7 mimics in U87 and U251 cells.Luciferase reporter assay was used to determine focal adhesion kinase (FAK) as a target of miR-7.The levels of miR-7,matrix metalloproteinases (MMP)-2 and MMP-9 mRNA were detected by PCR assay,and the levels of FAK,MMP-2,MMP-9,total and phosphorylation serine/threonine kinase (AKT),and extracellular signal-regulated kinase (ERK) 1/2 were measured by Western blotting analysis.Results Over-expression of miR-7 inhibited the invasion and migration activity of U87 and U251 cells.And up-regulation of miR-7 reduced FAK protein expression,Further,luciferase reporter assay showed that miR-7 modulated FAK expression directly by binding 3'UTR of FAK mRNA.In addition,miR-7 repressed p-ERK1/2 and p-AKT level,MMP-2 and MMP-9 expression.Finally,the inverse relationship between FAK and miR-7 expression was certificated in human glioma tissues.Conclusion To our knowledge,these data indicate for the first time that miR-7 directly regulates cell invasion by targeting FAK in glioblastoma and that miR-7 could be a potential therapeutic target for glioblastoma intervention.

  12. Focal adhesion kinase and mitogen-activated protein kinases are involved in chondrocyte activation by the 29-kDa amino-terminal fibronectin fragment.

    Science.gov (United States)

    Gemba, Takefumi; Valbracht, Jean; Alsalameh, Saifeddin; Lotz, Martin

    2002-01-11

    The 29-kDa amino-terminal fibronectin fragment (FN-f) has a potent chondrolytic effect and is thought to be involved in cartilage degradation in arthritis. However, little is known about signal transduction pathways that are activated by FN-f. Here we demonstrated that FN-f induced nitric oxide (NO) production from human articular chondrocytes. Expression of inducible nitric-oxide synthase (iNOS) mRNA and NO production were observed at 6 and 48 h after FN-f treatment, respectively. Interleukin-1beta (IL-1beta) mRNA up-regulation was stimulated by FN-f in human chondrocytes. To address the possibility that FN-f-induced NO release is mediated by IL-1beta production, the effect of IL-1 receptor antagonist (IL-1ra) was determined. IL-1ra partially inhibited FN-f-induced NO release although it almost completely inhibited IL-1beta-induced NO release. Tyrosine phosphorylation of focal adhesion kinase was induced transiently by FN-f treatment. Blocking antibodies to alpha(5) or beta(1) integrin and Arg-Gly-Asp-containing peptides did not inhibit FN-f-induced NO production. PP2, a Src family kinase inhibitor, or cytochalasin D, which selectively disrupts the network of actin filaments, inhibited both FAK phosphorylation and NO production induced by FN-f, but the phosphatidylinositol 3-kinase inhibitor wortmannin had no effect. Analysis of mitogen-activated protein kinases (MAPK) showed activation of extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase, and p38 MAPK. High concentrations of SB203580, which inhibit both JNK and p38 MAPK, and PD98059 a selective inhibitor of MEK1/2 that blocks ERK activation, inhibited FN-f induced NO production. These data suggest that focal adhesion kinase and MAPK mediate FN-f induced activation of human articular chondrocytes.

  13. Decreased astroglial cell adhesion and proliferation on zinc oxide nanoparticle polyurethane composites

    Directory of Open Access Journals (Sweden)

    Justin T Seil

    2008-11-01

    Full Text Available Justin T Seil, Thomas J WebsterLaboratory for Nanomedicine Research, Division of Engineering, Brown University, Providence, RI, USAAbstract: Nanomaterials offer a number of properties that are of interest to the field of neural tissue engineering. Specifically, materials that exhibit nanoscale surface dimensions have been shown to promote neuron function while simultaneously minimizing the activity of cells such as astrocytes that inhibit central nervous system regeneration. Studies demonstrating enhanced neural tissue regeneration in electrical fields through the use of conductive materials have led to interest in piezoelectric materials (or those materials which generate a transient electrical potential when mechanically deformed such as zinc oxide (ZnO. It has been speculated that ZnO nanoparticles possess increased piezoelectric properties over ZnO micron particles. Due to this promise in neural applications, the objective of the present in vitro study was, for the first time, to assess the activity of astroglial cells on ZnO nanoparticle polymer composites. ZnO nanoparticles embedded in polyurethane were analyzed via scanning electron microscopy to evaluate nanoscale surface features of the composites. The surface chemistry was characterized via X-ray photoelectron spectroscopy. Astroglial cell response was evaluated based on cell adhesion and proliferation. Astrocyte adhesion was significantly reduced on ZnO nanoparticle/polyurethane (PU composites with a weight ratio of 50:50 (PU:ZnO wt.%, 75:25 (PU:ZnO wt.%, and 90:10 (PU:ZnO wt.% in comparison to pure PU. The successful production of ZnO nanoparticle composite scaffolds suitable for decreasing astroglial cell density demonstrates their potential as a nerve guidance channel material with greater efficiency than what may be available today.Keywords: zinc oxide, nanoparticles, astrocytes, neural tissue, nervous system, biomaterials

  14. Decreasing adhesions and avoiding further surgery in a pediatric patient involved in a severe pedestrian versus motor vehicle accident

    Directory of Open Access Journals (Sweden)

    Amanda D. Rice

    2014-02-01

    Full Text Available In this case study, we report the use of manual physical therapy in a pediatric patient experiencing complications from a life-threatening motor vehicle accident that necessitated 19 surgeries over the course of 12 months. Post-surgical adhesions decreased the patient’s quality of life. He developed multiple medical conditions including recurrent partial bowel obstructions and an ascending testicle. In an effort to avoid further surgery for bowel obstruction and the ascending testicle, the patient was effectively treated with a manual physical therapy regimen focused on decreasing adhesions. The therapy allowed return to an improved quality of life, significant decrease in subjective reports of pain and dysfunction, and apparent decreases in adhesive processes without further surgery, which are important goals for all patients, but especially for pediatric patients.

  15. Laminin α2-mediated focal adhesion kinase activation triggers Alport glomerular pathogenesis.

    Science.gov (United States)

    Delimont, Duane; Dufek, Brianna M; Meehan, Daniel T; Zallocchi, Marisa; Gratton, Michael Anne; Phillips, Grady; Cosgrove, Dominic

    2014-01-01

    It has been known for some time that laminins containing α1 and α2 chains, which are normally restricted to the mesangial matrix, accumulate in the glomerular basement membranes (GBM) of Alport mice, dogs, and humans. We show that laminins containing the α2 chain, but not those containing the α1 chain activates focal adhesion kinase (FAK) on glomerular podocytes in vitro and in vivo. CD151-null mice, which have weakened podocyte adhesion to the GBM rendering these mice more susceptible to biomechanical strain in the glomerulus, also show progressive accumulation of α2 laminins in the GBM, and podocyte FAK activation. Analysis of glomerular mRNA from both models demonstrates significant induction of MMP-9, MMP-10, MMP-12, MMPs linked to GBM destruction in Alport disease models, as well as the pro-inflammatory cytokine IL-6. SiRNA knockdown of FAK in cultured podocytes significantly reduced expression of MMP-9, MMP-10 and IL-6, but not MMP-12. Treatment of Alport mice with TAE226, a small molecule inhibitor of FAK activation, ameliorated fibrosis and glomerulosclerosis, significantly reduced proteinuria and blood urea nitrogen levels, and partially restored GBM ultrastructure. Glomerular expression of MMP-9, MMP-10 and MMP-12 mRNAs was significantly reduced in TAE226 treated animals. Collectively, this work identifies laminin α2-mediated FAK activation in podocytes as an important early event in Alport glomerular pathogenesis and suggests that FAK inhibitors, if safe formulations can be developed, might be employed as a novel therapeutic approach for treating Alport renal disease in its early stages.

  16. Laminin α2-mediated focal adhesion kinase activation triggers Alport glomerular pathogenesis.

    Directory of Open Access Journals (Sweden)

    Duane Delimont

    Full Text Available It has been known for some time that laminins containing α1 and α2 chains, which are normally restricted to the mesangial matrix, accumulate in the glomerular basement membranes (GBM of Alport mice, dogs, and humans. We show that laminins containing the α2 chain, but not those containing the α1 chain activates focal adhesion kinase (FAK on glomerular podocytes in vitro and in vivo. CD151-null mice, which have weakened podocyte adhesion to the GBM rendering these mice more susceptible to biomechanical strain in the glomerulus, also show progressive accumulation of α2 laminins in the GBM, and podocyte FAK activation. Analysis of glomerular mRNA from both models demonstrates significant induction of MMP-9, MMP-10, MMP-12, MMPs linked to GBM destruction in Alport disease models, as well as the pro-inflammatory cytokine IL-6. SiRNA knockdown of FAK in cultured podocytes significantly reduced expression of MMP-9, MMP-10 and IL-6, but not MMP-12. Treatment of Alport mice with TAE226, a small molecule inhibitor of FAK activation, ameliorated fibrosis and glomerulosclerosis, significantly reduced proteinuria and blood urea nitrogen levels, and partially restored GBM ultrastructure. Glomerular expression of MMP-9, MMP-10 and MMP-12 mRNAs was significantly reduced in TAE226 treated animals. Collectively, this work identifies laminin α2-mediated FAK activation in podocytes as an important early event in Alport glomerular pathogenesis and suggests that FAK inhibitors, if safe formulations can be developed, might be employed as a novel therapeutic approach for treating Alport renal disease in its early stages.

  17. Defining central themes in breast cancer biology by differential proteomics: conserved regulation of cell spreading and focal adhesion kinase.

    Science.gov (United States)

    Bateman, Nicholas W; Sun, Mai; Hood, Brian L; Flint, Melanie S; Conrads, Thomas P

    2010-10-01

    Breast cancer is a highly heterogeneous disease, an observation that underscores the importance of elucidating conserved molecular characteristics, such as gene and protein expression, across breast cancer cell types toward providing a greater understanding of context-specific features central to this disease. Motivated by the goal of defining central biological themes across breast cancer cell subtypes, we conducted a global proteomic analysis of three breast cancer cell lines, MCF7, SK-BR-3, and MDA-MB-231, and compared these to a model of nontransformed mammary cells (MCF10A). Our results demonstrate modulation of proteins localized to the extracellular matrix, plasma membrane, and nucleus, along with coordinate decreases in proteins that regulate "cell spreading," a cellular event previously shown to be dysregulated in transformed cells. Protein interaction network analysis revealed the clustering of focal adhesion kinase (FAK), a fundamental regulator of cell spreading, with several proteins identified as mutually, differentially abundant across breast cancer cell lines that impact expression and activity of FAK, such as neprilysin and keratin 19. These analyses provide insights into conservation of protein expression across breast cancer cell subtypes, a subset of which warrants further investigation for their roles in the regulation of cell spreading and FAK in breast cancer.

  18. Protective influence of hyaluronic acid on focal adhesion kinase activity in human skin fibroblasts exposed to ethanol

    Science.gov (United States)

    Donejko, Magdalena; Rysiak, Edyta; Galicka, Elżbieta; Terlikowski, Robert; Głażewska, Edyta Katarzyna; Przylipiak, Andrzej

    2017-01-01

    Aim The aim of this study was to evaluate the effect of ethanol and hyaluronic acid (HA) on cell survival and apoptosis in cultured human skin fibroblasts. Regarding the mechanism of ethanol action on human skin fibroblasts, we investigated cell viability and apoptosis, expression of focal adhesion kinase (FAK), and the influence of HA on those processes. Materials and methods Studies were conducted in confluent human skin fibroblast cultures that were treated with 25 mM, 50 mM, and 100 mM ethanol or with ethanol and 500 µg/mL HA. Cell viability was examined using methyl thiazolyl tetrazolium (MTT) assay and NC-300 Nucleo-Counter. Imaging of the cells using a fluorescence microscope Pathway 855 was performed to measure FAK expression. Results Depending on the dosage, ethanol decreased cell viability and activated the process of apoptosis in human skin fibroblasts. HA prevented the negative influence of ethanol on cell viability and prevented apoptosis. The analysis of fluorescence imaging using BD Pathway 855 High-Content Bioimager showed the inhibition of FAK migration to the cell nucleus, depending on the increasing concentration of ethanol. Conclusion This study proves that downregulation of signaling pathway of FAK is involved in ethanol-induced apoptosis in human skin fibroblasts. The work also indicates a protective influence of HA on FAK activity in human skin fibroblasts exposed to ethanol. PMID:28293103

  19. C1q/TNF-related protein-9 inhibits cytokine-induced vascular inflammation and leukocyte adhesiveness via AMP-activated protein kinase activation in endothelial cells.

    Science.gov (United States)

    Jung, Chang Hee; Lee, Min Jung; Kang, Yu Mi; Lee, Yoo La; Seol, So Mi; Yoon, Hae Kyeong; Kang, Sang-Wook; Lee, Woo Je; Park, Joong-Yeol

    2016-01-05

    Although recent studies have reported cardioprotective effects of C1q/TNF-related protein 9 (CTRP9), the closet adiponectin paralog, its role on cytokine-induced endothelial inflammation is unknown. We investigated whether CTRP9 prevented inflammatory cytokine-induced nuclear factor-kappa B (NF-κB) activation and inhibited the expression of adhesion molecules and a chemokine in the vascular endothelial cell. We used human aortic endothelial cells (HAECs) to examine the effects of CTRP9 on NF-κB activation and the expression of NF-κB-mediated genes, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1). Tumor necrosis factor alpha (TNFα) was used as a representative proinflammatory cytokine. In an adhesion assay using THP-1 cells, CTRP9 reduced TNFα-induced adhesion of monocytes to HAECs. Treatment with CTRP9 significantly decreased TNFα-induced activation of NF-κB, as well as the expression of ICAM-1, VCAM-1, and MCP-1. In addition, treatment with CTRP9 significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), the downstream target of AMPK. The inhibitory effect of CTRP9 on the expression of ICAM-1, VCAM-1, and MCP-1 and monocyte adhesion to HAECs was abolished after transfection with an AMPKα1-specific siRNA. Our study is the first to demonstrate that CTRP9 attenuates cytokine-induced vascular inflammation in endothelial cells mediated by AMPK activation.

  20. Integrins stimulate E-cadherin-mediated intercellular adhesion by regulating Src-kinase activation and actomyosin contractility.

    Science.gov (United States)

    Martinez-Rico, Clara; Pincet, Frederic; Thiery, Jean-Paul; Dufour, Sylvie

    2010-03-01

    Cadherins and integrins are major adhesion molecules regulating cell-cell and cell-matrix interactions. In vitro and in vivo studies have demonstrated the existence of crosstalk between integrins and cadherins in cell adhesion and motility. We used a dual pipette assay to measure the force required to separate E-cadherin-producing cell doublets and to investigate the role of integrin in regulating the strength of intercellular adhesion. A greater force was required to separate cell doublets bound to fibronectin or vitronectin-coated beads than for doublets bound to polylysine-coated beads. This effect depended on cell spreading and the duration of stimulation. Cells expressing type II cadherin-7 also responded to fibronectin stimulation to produce a higher intercellular adhesion. Establishment of cadherin-mediated adhesion needed ROCK, MLCK and myosin ATPase II activity. The regulation of intercellular adhesion strength by integrin stimulation required activation of Src family kinases, ROCK and actomyosin contractility. These findings highlight the importance and mechanisms of molecular crosstalk between cadherins and integrins in the control of cell plasticity during histogenesis and morphogenesis.

  1. The oncogenic epidermal growth factor receptor variant Xiphophorus melanoma receptor kinase induces motility in melanocytes by modulation of focal adhesions.

    Science.gov (United States)

    Meierjohann, Svenja; Wende, Elisabeth; Kraiss, Anita; Wellbrock, Claudia; Schartl, Manfred

    2006-03-15

    One of the most prominent features of malignant melanoma is the fast generation of metastasizing cells, resulting in the poor prognosis of patients with this tumor type. For this process, cells must gain the ability to migrate. The oncogenic receptor Xmrk (Xiphophorus melanoma receptor kinase) from the Xiphophorus melanoma system is a mutationally activated version of the epidermal growth factor receptor that induces the malignant transformation of pigment cells. Here, we show that the activation of Xmrk leads to a clear increase of pigment cell motility in a fyn-dependent manner. Stimulation of Xmrk induces its interaction with the focal adhesion kinase (FAK) and the interaction of active, receptor-bound fyn with FAK. This results in changes in FAK activity and induces the modulation of stress fibers and focal adhesions. Overexpression of dominant-negative FAK shows that the activity of innate FAK and a receptor-induced focal adhesion turnover are a prerequisite for pigment cell migration. Our findings show that in our system, Xmrk is sufficient for the induction of pigment cell motility and underlines a role of the src family protein tyrosine kinase fyn in melanoma development and progression.

  2. Organization and post-transcriptional processing of focal adhesion kinase gene

    Directory of Open Access Journals (Sweden)

    Enslen Hervé

    2006-08-01

    Full Text Available Abstract Background Focal adhesion kinase (FAK is a non-receptor tyrosine kinase critical for processes ranging from embryo development to cancer progression. Although isoforms with specific molecular and functional properties have been characterized in rodents and chicken, the organization of FAK gene throughout phylogeny and its potential to generate multiple isoforms are not well understood. Here, we study the phylogeny of FAK, the organization of its gene, and its post-transcriptional processing in rodents and human. Results A single orthologue of FAK and the related PYK2 was found in non-vertebrate species. Gene duplication probably occurred in deuterostomes after the echinoderma embranchment, leading to the evolution of PYK2 with distinct properties. The amino acid sequence of FAK and PYK2 is conserved in their functional domains but not in their linker regions, with the absence of autophosphorylation site in C. elegans. Comparison of mouse and human FAK genes revealed the existence of multiple combinations of conserved and non-conserved 5'-untranslated exons in FAK transcripts suggesting a complex regulation of their expression. Four alternatively spliced coding exons (13, 14, 16, and 31, previously described in rodents, are highly conserved in vertebrates. Cis-regulatory elements known to regulate alternative splicing were found in conserved alternative exons of FAK or in the flanking introns. In contrast, other reported human variant exons were restricted to Homo sapiens, and, in some cases, other primates. Several of these non-conserved exons may correspond to transposable elements. The inclusion of conserved alternative exons was examined by RT-PCR in mouse and human brain during development. Inclusion of exons 14 and 16 peaked at the end of embryonic life, whereas inclusion of exon 13 increased steadily until adulthood. Study of various tissues showed that inclusion of these exons also occurred, independently from each other, in a

  3. Doxycycline inhibits leukemic cell migration via inhibition of matrix metalloproteinases and phosphorylation of focal adhesion kinase.

    Science.gov (United States)

    Wang, Chunhuai; Xiang, Ru; Zhang, Xiangzhong; Chen, Yunxian

    2015-09-01

    Doxycycline, a tetracycline-based antibiotic, has been reported to attenuate melanoma cell migration through inhibiting the focal adhesion kinase (FAK) signaling pathway. However, it remains to be elucidated whether doxycycline exerts this effect on leukemia cell migration. The present study aimed to examine the role of doxycycline in leukemia cell migration. The invasion capacities of the human leukemia cell lines KG1a (acute myelogenous leukemia) and K562 (chronic myelogenous leukemia) were evaluated using Matrigel® matrix‑coated Transwell® chamber assays; leukemic cell lines treated with doxycycline (1 µg/ml) or anti‑β1‑integrin antibodies were added to the upper chamber, while untreated cells were included as controls. Reverse transcription quantitative polymerase chain reaction was performed in order to further understand the influence of doxycycline treatment on the expression of FAK and gelatinases in the KG1a and K562 leukemic cell lines. In addition, FAK protein expression and phosphorylation were determined using western blot analysis in order to investigate the mechanism by which doxycycline inhibited leukemic cell migration. The results revealed that doxycycline treatment significantly attenuated the migration of KG1a and K562 cells, which was demonstrated to be associated with inhibition of the expression and phosphorylation of FAK. In addition, doxycycline treatment inhibited matrix metalloproteinase (MMP)‑2 and MMP‑9 expression. Furthermore, incubation with blocking anti‑β1‑integrin antibodies had an analogous inhibitory effect on leukemic cell migration to that of doxycycline. In conclusion, the results of the present study suggested that doxycycline attenuated leukemic cell migration through inhibiting the FAK signaling pathway. Therefore, doxycycline may have potential for use as a novel strategy for the treatment of leukemia.

  4. Phosphatidylinositol 3-kinase mediates the ability of retinol to decrease colorectal cancer cell invasion.

    Science.gov (United States)

    Lengyel, Jennifer N Griffin; Park, Eun Young; Brunson, Anna R; Pinali, Daniel; Lane, Michelle A

    2014-01-01

    Previously, we showed that retinol (vitamin A) decreased both colorectal cancer cell invasion and phosphatidylinositol 3-kinase (PI3K) activity through a retinoic acid receptor-independent mechanism. Here, we determined if these phenomena were related by using parental HCT-116 cells that harbor 1 allele of wild-type PI3K and 1 allele of constitutively active (ca) PI3K and 2 mutant HCT-116 cell lines homozygous for caPI3K. In vitro, treatment of parental HCT-116 cells with 10 μM retinol reduced cell invasion whereas treatment of mutant HCT-116 cell lines with retinol did not. Treatment with 10 μM retinol also decreased the activity of matrixmetalloproteinase-9 and increased tissue inhibitor of matrixmetalloproteinase-I levels in parental, but not mutant, HCT-116 cells. Finally, parental or mutant cells were intrasplenically injected into athymic mice consuming diets with or without supplemental vitamin A. As expected, vitamin A supplementation tended (P = 0.18) to reduce the incidence of metastases in mice injected with the parental cell line and consuming the supplemented diet. In contrast, metastatic incidence was not affected (P = 1.00) by vitamin A supplementation in mice injected with mutant cells. These data indicate that the capacity of retinol to inhibit PI3K activity confers its ability to decrease colorectal cancer metastasis.

  5. Cables links Robo-bound Abl kinase to N-cadherin-bound beta-catenin to mediate Slit-induced modulation of adhesion and transcription.

    Science.gov (United States)

    Rhee, Jinseol; Buchan, Tim; Zukerberg, Lawrence; Lilien, Jack; Balsamo, Janne

    2007-08-01

    Binding of the secreted axon guidance cue Slit to its Robo receptor results in inactivation of the neural, calcium-dependent cell-cell adhesion molecule N-cadherin, providing a rapid epigenetic mechanism for integrating guidance and adhesion information. This requires the formation of a multimolecular complex containing Robo, Abl tyrosine kinase and N-cadherin. Here we show that on binding of Slit to Robo, the adaptor protein Cables is recruited to Robo-associated Abl and forms a multimeric complex by binding directly to N-cadherin-associated beta-catenin. Complex formation results in Abl-mediated phosphorylation of beta-catenin on tyrosine 489, leading to a decrease in its affinity for N-cadherin, loss of N-cadherin function, and targeting of phospho-Y489-beta-catenin to the nucleus. Nuclear beta-catenin combines with the transcription factor Tcf/Lef and activates transcription. Thus, Slit-induced formation of the Robo-N-cadherin complex results in a rapid loss of cadherin-mediated adhesion and has more lasting effects on gene transcription.

  6. Focal adhesion kinase is a phospho-regulated repressor of Rac and proliferation in human endothelial cells

    Directory of Open Access Journals (Sweden)

    Patrick W. Bryant

    2012-06-01

    Focal adhesion kinase (FAK is critically positioned to integrate signals from the extracellular matrix and cellular adhesion. It is essential for normal vascular development and has been implicated in a wide range of cellular functions including the regulation of cell proliferation, migration, differentiation, and survival. It is currently being actively targeted therapeutically using different approaches. We have used human endothelial cells as a model system to compare the effects of inhibiting FAK through several different approaches including dominant negatives, kinase inhibitors and shRNA. We find that manipulations of FAK signaling that result in inhibition of FAK 397 phosphorylation inhibit proliferation and migration. However, abolition of FAK expression using stable (shRNA or transient (siRNA approaches does not interfere with these cellular functions. The ability to regulate cell proliferation by FAK manipulation is correlated with the activation status of Rac, an essential signal for the regulation of cyclin-dependent kinase inhibitors. The knockdown of FAK, while not affecting cellular proliferation or migration, dramatically interferes with vascular morphogenesis and survival, mirroring in vivo findings. We propose a novel model of FAK signaling whereby one of the multifunctional roles of FAK as a signaling protein includes FAK as a phospho-regulated repressor of Rac activation, with important implications on interpretation of research experiments and therapeutic development.

  7. Decrease of Staphylococcal adhesion on surgical stainless steel after Si ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Braceras, Iñigo, E-mail: inigo.braceras@tecnalia.com [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Pacha-Olivenza, Miguel A. [CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); Calzado-Martín, Alicia [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Multigner, Marta [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vera, Carolina [Tecnalia, Mikeletegi Pasealekua 2, 20009 Donostia-San Sebastian (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Broncano, Luis Labajos-; Gallardo-Moreno, Amparo M. [Universidad de Extremadura, Departamento de Física Aplicada, Facultad de Ciencias, Av. Elvas s/n, 06006 Badajoz (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); González-Carrasco, José Luis [Centro Nacional de Investigaciones Metalúrgicas, CENIM-CSIC, Avda Gregorio del Amo 8, 28040 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); Vilaboa, Nuria [Hospital Universitario La Paz-IdiPAZ, Paseo de la Castellana 261, 28046 Madrid (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN) (Spain); and others

    2014-08-15

    Highlights: • Si ion implantation of AISI 316LVM medical grade alloy might reduce bacterial adhesion and colonization. • Si ion implantation does not impair the attachment, viability and matrix maturation of human mesenchymal stem cells. • Nano-topography and surface chemistry changes account for the Si ion implantation induced effects. - Abstract: 316LVM austenitic stainless steel is often the material of choice on temporal musculoskeletal implants and surgical tools as it combines good mechanical properties and acceptable corrosion resistance to the physiologic media, being additionally relatively inexpensive. This study has aimed at improving the resistance to bacterial colonization of this surgical stainless steel, without compromising its biocompatibility and resistance. To achieve this aim, the effect of Si ion implantation on 316LVM has been studied. First, the effect of the ion implantation parameters (50 keV; fluence: 2.5–5 × 10{sup 16} ions/cm{sup 2}; angle of incidence: 45–90°) has been assessed in terms of depth profiling of chemical composition by XPS and nano-topography evaluation by AFM. The in vitro biocompatibility of the alloy has been evaluated with human mesenchymal stem cells. Finally, bacterial adhesion of Staphylococcus epidermidis and Staphylococcus aureus on these surfaces has been assessed. Reduction of bacterial adhesion on Si implanted 316LVM is dependent on the implantation conditions as well as the features of the bacterial strains, offering a promising implantable biomaterial in terms of biocompatibility, mechanical properties and resistance to bacterial colonization. The effects of surface composition and nano-topography on bacterial adhesion, directly related to ion implantation conditions, are also discussed.

  8. Rutin inhibits proliferation, attenuates superoxide production and decreases adhesion and migration of human cancerous cells.

    Science.gov (United States)

    Ben Sghaier, Mohamed; Pagano, Alessandra; Mousslim, Mohamed; Ammari, Youssef; Kovacic, Hervé; Luis, José

    2016-12-01

    Lung and colorectal cancer are the principal causes of death in the world. Rutin, an active flavonoid compound, is known for possessing a wide range of biological activities. In this study, we examined the effect of rutin on the viability, superoxide anion production, adhesion and migration of human lung (A549) and colon (HT29 and Caco-2) cancer cell lines. In order to control the harmlessness of the tested concentrations of rutin, the viability of cancer cell lines was assessed using a 3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) assay. ROS generation was measured by lucigenin chemiluminescence detecting superoxide ions. To investigate the effect of rutin on the behavior of human lung and colon cancer cell lines, we performed adhesion assays, using various purified extracellular matrix (ECM) proteins. Finally, in vitro cell migration assays were explored using modified Boyden chambers. The viability of cancerous cells was inhibited by rutin. It also significantly attenuated the superoxide production in HT29 cells. In addition, rutin affected adhesion and migration of A549 and HT29 cell. These findings indicate that rutin, a natural molecule, might have potential as anticancer agent against lung and colorectal carcinogenesis.

  9. Focal adhesion kinase antisense oligodeoxynucleotides inhibit human pulmonary artery smooth muscle cells proliferation and promote human pulmonary artery smooth muscle cells apoptosis

    Institute of Scientific and Technical Information of China (English)

    LIN Chun-long; ZHANG Zhen-xiang; XU Yong-jian; NI Wang; CHEN Shi-xin

    2005-01-01

    Background Pulmonary artery smooth muscle cell (PASMC) proliferation plays an important role in pulmonary vessel structural remodelling. At present, the mechanisms related to proliferation of PASMCs are not clear. Focal adhesion kinase (FAK) is a widely expressed nonreceptor protein tyrosine kinase. Recent research indicates that FAK is implicated in signalling pathways which regulate cytoskeletal organization, adhesion, migration, survival and proliferation of cells. Furthermore, there are no reports about the role of FAK in human pulmonary artery smooth muscle cells (HPASMCs). We investigated whether FAK takes part in the intracellular signalling pathway involved in HPASMCs proliferation and apoptosis, by using antisense oligodeoxynucleotides (ODNs) to selectively suppress the expression of FAK protein.Methods Cultured HPASMCs stimulated by fibronectin (40 μg/ml) were passively transfected with ODNs, sense FAK, mismatch sense and antisense-FAK respectively. Expression of FAK, Jun NH2-terminal kinase (JNK), cyclin-dependent kinase 2 (CDK 2) and caspase-3 proteins were detected by immunoprecipitation and Western blots. Cell cycle and cell apoptosis were analysed by flow cytometry. In addition, cytoplasmic FAK expression was detected by immunocytochemical staining.Results When compared with mismatch sense group, the protein expressions of FAK, JNK and CDK 2 in HPASMCs decreased in antisense-FAK ODNs group and increased in sense-FAK ODNs group significantly. Caspase-3 expression upregulated in HPASMCs when treated with antisense ODNs and downregulated when treated with sense ODNs. When compared with mismatch sense ODNs group, the proportion of cells at G1 phase decreased significantly in sense ODNs group, while the proportion of cells at S phase increased significantly. In contrast, compared with mismatch sense ODNs group, the proportion of cells at G1 phase was increased significantly in antisense-FAK ODNs group. The level of cell apoptosis in antisense-FAK group

  10. Protein kinase C, focal adhesions and the regulation of cell migration

    DEFF Research Database (Denmark)

    Fogh, Betina S; Multhaupt, Hinke A B; Couchman, John Robert

    2014-01-01

    Cell adhesion to extracellular matrix is a complex process involving protrusive activity driven by the actin cytoskeleton, engagement of specific receptors, followed by signaling and cytoskeletal organization. Thereafter, contractile and endocytic/recycling activities may facilitate migration...

  11. Mesalamine modulates intercellular adhesion through inhibition of p-21 activated kinase-1.

    Science.gov (United States)

    Khare, Vineeta; Lyakhovich, Alex; Dammann, Kyle; Lang, Michaela; Borgmann, Melanie; Tichy, Boris; Pospisilova, Sarka; Luciani, Gloria; Campregher, Christoph; Evstatiev, Rayko; Pflueger, Maren; Hundsberger, Harald; Gasche, Christoph

    2013-01-15

    Mesalamine (5-ASA) is widely used for the treatment of ulcerative colitis, a remitting condition characterized by chronic inflammation of the colon. Knowledge about the molecular and cellular targets of 5-ASA is limited and a clear understanding of its activity in intestinal homeostasis and interference with neoplastic progression is lacking. We sought to identify molecular pathways interfered by 5-ASA, using CRC cell lines with different genetic background. Microarray was performed for gene expression profile of 5-ASA-treated and untreated cells (HCT116 and HT29). Filtering and analysis of data identified three oncogenic pathways interfered by 5-ASA: MAPK/ERK pathway, cell adhesion and β-catenin/Wnt signaling. PAK1 emerged as a consensus target of 5-ASA, orchestrating these pathways. We further investigated the effect of 5-ASA on cell adhesion. 5-ASA increased cell adhesion which was measured by cell adhesion assay and transcellular-resistance measurement. Moreover, 5-ASA treatment restored membranous expression of adhesion molecules E-cadherin and β-catenin. Role of PAK1 as a mediator of mesalamine activity was validated in vitro and in vivo. Inhibition of PAK1 by RNA interference also increased cell adhesion. PAK1 expression was elevated in APC(min) polyps and 5-ASA treatment reduced its expression. Our data demonstrates novel pharmacological mechanism of mesalamine in modulation of cell adhesion and role of PAK1 in APC(min) polyposis. We propose that inhibition of PAK1 expression by 5-ASA can impede with neoplastic progression in colorectal carcinogenesis. The mechanism of PAK1 inhibition and induction of membranous translocation of adhesion proteins by 5-ASA might be independent of its known anti-inflammatory action.

  12. Nicotine stimulates adhesion molecular expression via calcium influx and mitogen-activated protein kinases in human endothelial cells.

    Science.gov (United States)

    Wang, Yajing; Wang, Zhaoxia; Zhou, Ying; Liu, Liming; Zhao, Yangxing; Yao, Chenjiang; Wang, Lianyun; Qiao, Zhongdong

    2006-02-01

    To evaluate the effect of nicotine on endothelium dysfunction and development of vascular diseases, we investigated the influence on adhesion molecular expression mediated by nicotine and the mechanism of this effect in human umbilical vein endothelial cells (HUVECs). The result showed that nicotine could induce surface/soluble vascular cell adhesion molecule (VCAM-1) and endothelial selectin (E-selectin) expression in a time-response decline manner and the peak appeared at 15 min. This action could be mediated by mitogen-activated protein kinase/extracellular signal regulated kinase 1/2 (MAPK/ERK1/2) and MAPK/p38 because their activation could be distinctly blocked by MAPK inhibitors, PD098059 or SB203580. Mecamylamine (non-selective nicotinic receptor inhibitor), alpha-bungarotoxin (alpha7 nicotinic receptor inhibitor) could block Ca2+ accumulation, and then, prevented the phosphorylation on ERK1/2 and p38. They also inhibited the surface/soluble VCAM-1, E-selectin production of HUVECs modulated by nicotine. Therefore, we concluded that: (i) nicotine obviously up-regulates VCAM-1 and E-selectin expression at 15 min in HUVECs, (ii) nicotine activates HUVECs triggered by the ERK1/2 and p38 phosphorylation with an involvement of intracellular calcium mobilization chiefly mediated by alpha7 nicotinic receptor, (iii) intracellular Ca2+ activates a sequential pathway from alpha7 nicotinic receptor to the phosphorylation of ERK1/2, p38. These elucidate that nicotine activates HUVECs through fast signal transduction pathway and arguments their capacity of adhesion molecular production. Further more nicotine may contribute its influence to the progression of vascular disease such as atherosclerotic lesion.

  13. Lectin receptor kinases participate in protein-protein interactions to mediate plasma membrane-cell wall adhesions in Arabidopsis.

    Science.gov (United States)

    Gouget, Anne; Senchou, Virginie; Govers, Francine; Sanson, Arnaud; Barre, Annick; Rougé, Pierre; Pont-Lezica, Rafael; Canut, Hervé

    2006-01-01

    Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown. Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis (Arabidopsis thaliana), are disrupted by the RGD (arginine-glycine-aspartic acid) tripeptide sequence, a characteristic cell adhesion motif in mammals. In planta induced-O (IPI-O) is an RGD-containing protein from the plant pathogen Phytophthora infestans that can disrupt cell wall-plasma membrane adhesions through its RGD motif. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis. Moreover, the two peptides also disrupted cell wall-plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g60300, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces.

  14. Lectin Receptor Kinases Participate in Protein-Protein Interactions to Mediate Plasma Membrane-Cell Wall Adhesions in Arabidopsis1

    Science.gov (United States)

    Gouget, Anne; Senchou, Virginie; Govers, Francine; Sanson, Arnaud; Barre, Annick; Rougé, Pierre; Pont-Lezica, Rafael; Canut, Hervé

    2006-01-01

    Interactions between plant cell walls and plasma membranes are essential for cells to function properly, but the molecules that mediate the structural continuity between wall and membrane are unknown. Some of these interactions, which are visualized upon tissue plasmolysis in Arabidopsis (Arabidopsis thaliana), are disrupted by the RGD (arginine-glycine-aspartic acid) tripeptide sequence, a characteristic cell adhesion motif in mammals. In planta induced-O (IPI-O) is an RGD-containing protein from the plant pathogen Phytophthora infestans that can disrupt cell wall-plasma membrane adhesions through its RGD motif. To identify peptide sequences that specifically bind the RGD motif of the IPI-O protein and potentially play a role in receptor recognition, we screened a heptamer peptide library displayed in a filamentous phage and selected two peptides acting as inhibitors of the plasma membrane RGD-binding activity of Arabidopsis. Moreover, the two peptides also disrupted cell wall-plasma membrane adhesions. Sequence comparison of the RGD-binding peptides with the Arabidopsis proteome revealed 12 proteins containing amino acid sequences in their extracellular domains common with the two RGD-binding peptides. Eight belong to the receptor-like kinase family, four of which have a lectin-like extracellular domain. The lectin domain of one of these, At5g60300, recognized the RGD motif both in peptides and proteins. These results imply that lectin receptor kinases are involved in protein-protein interactions with RGD-containing proteins as potential ligands, and play a structural and signaling role at the plant cell surfaces. PMID:16361528

  15. DDR2 plays a role in fibroblast migration independent of adhesion ligand and collagen activated DDR2 tyrosine kinase.

    Science.gov (United States)

    Herrera-Herrera, Mireya Liliana; Quezada-Calvillo, Roberto

    2012-12-07

    Discoidin domain receptor-2 (DDR2) is a cell surface tyrosine kinase receptor that can be activated by soluble collagen and has been implicated in diverse physiological functions including organism growth and wound repair. In the current studies, we used fibronectin and collagen-coated 2D surfaces and collagen matrices in combination with siRNA technology to investigate the role of DDR2 in a range of fibroblast motile activities. Silencing DDR2 with siRNA inhibited cell spreading and migration, and similar inhibition occurred regardless whether cells were interacting with fibronectin or collagen surfaces. Under the assay conditions used, DDR2 tyrosine kinase activation was not observed unless soluble collagen was added to the incubation medium. Finally silencing DDR2 also inhibited human fibroblast migration in 3D collagen matrices but had no effect on 3D collagen matrix remodeling and contraction. Taken together, our findings suggest that DDR2 is required for normal fibroblast spreading and migration independent of adhesion ligand and collagen activation of DDR2 tyrosine kinase.

  16. Focal adhesion kinase-mediated activation of glycogen synthase kinase 3β regulates IL-33 receptor internalization and IL-33 signaling.

    Science.gov (United States)

    Zhao, Jing; Wei, Jianxin; Bowser, Rachel K; Traister, Russell S; Fan, Ming-Hui; Zhao, Yutong

    2015-01-15

    IL-33, a relatively new member of the IL-1 cytokine family, plays a crucial role in allergic inflammation and acute lung injury. Long form ST2 (ST2L), the receptor for IL-33, is expressed on immune effector cells and lung epithelia and plays a critical role in triggering inflammation. We have previously shown that ST2L stability is regulated by the ubiquitin-proteasome system; however, its upstream internalization has not been studied. In this study, we demonstrate that glycogen synthase kinase 3β (GSK3β) regulates ST2L internalization and IL-33 signaling. IL-33 treatment induced ST2L internalization, and an effect was attenuated by inhibition or downregulation of GSK3β. GSK3β was found to interact with ST2L on serine residue 446 in response to IL-33 treatment. GSK3β binding site mutant (ST2L(S446A)) and phosphorylation site mutant (ST2L(S442A)) are resistant to IL-33-induced ST2L internalization. We also found that IL-33 activated focal adhesion kinase (FAK). Inhibition of FAK impaired IL-33-induced GSK3β activation and ST2L internalization. Furthermore, inhibition of ST2L internalization enhanced IL-33-induced cytokine release in lung epithelial cells. These results suggest that modulation of the ST2L internalization by FAK/GSK3β might serve as a unique strategy to lessen pulmonary inflammation.

  17. Matriptase is required for the active form of hepatocyte growth factor induced Met, focal adhesion kinase and protein kinase B activation on neural stem/progenitor cell motility.

    Science.gov (United States)

    Fang, Jung-Da; Lee, Sheau-Ling

    2014-07-01

    Hepatocyte growth factor (HGF) is a chemoattractant and inducer for neural stem/progenitor (NS/P) cell migration. Although the type II transmembrane serine protease, matriptase (MTP) is an activator of the latent HGF, MTP is indispensable on NS/P cell motility induced by the active form of HGF. This suggests that MTP's action on NS/P cell motility involves mechanisms other than proteolytic activation of HGF. In the present study, we investigate the role of MTP in HGF-stimulated signaling events. Using specific inhibitors of phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt) or focal adhesion kinase (FAK), we demonstrated that in NS/P cells HGF-activated c-Met induces PI3k-Akt signaling which then leads to FAK activation. This signaling pathway ultimately induces MMP2 expression and NS/P cell motility. Knocking down of MTP in NS/P cells with specific siRNA impaired HGF-stimulation of c-Met, Akt and FAK activation, blocked HGF-induced production of MMP2 and inhibited HGF-stimulated NS/P cell motility. MTP-knockdown NS/P cells cultured in the presence of recombinant protein of MTP protease domain or transfected with the full-length wild-type but not the protease-defected MTP restored HGF-responsive events in NS/P cells. In addition to functioning as HGF activator, our data revealed novel function of MTP on HGF-stimulated c-Met signaling activation.

  18. Focal adhesion kinase and Src phosphorylations in HGF-induced proliferation and invasion of human cholangiocarcinoma cell line, HuCCA-1

    Institute of Scientific and Technical Information of China (English)

    Urai Pongchairerk; Jun-Lin Guan; Vijittra Leardkamolkarn

    2005-01-01

    AIM: To study the role of focal adhesion kinase (FAK) and its association with Src in hepatocyte growth factor (HGF)-induced cell signaling in cholangiocarcinoma progression.METHODS: Previously isolated HuCCA-1 cells were re-characterized by immunofluorescent staining and reverse transcriptase-polymerase chain reaction assay for the expression of cytokeratin 19, HGF and c-Met mRNA. Cultured HuCCA-1 cells were treated with HGF and determined for cell proliferation and invasion effects by MTT and invasion assays. Western blotting, immunoprecipitation, and co-immunoprecipitation were also performed to study the phosphorylation and interaction of FAK and Src. A novel Src inhibitor (AZM555130) was applied in cultures to investigate the effects on FAK phosphorylation inhibition and on cell proliferation and invasion.RESULTS: HGF enhanced HuCCA-1 cell proliferation and invasion by mediating FAK and Src phosphorylations.FAK-Src interaction occurred in a time-dependent manner that Src was proved to be an upstream signaling molecule to FAK. The inhibitor to Src decreased FAK phosphorylation level in correlation with the reduction of cell proliferation and invasion.CONCLUSION: FAK plays a significant role in signaling pathway of HGF-responsive cell line derived from cholangiocarcinoma. Autophosphorylated Src, induced by HGF, mediates Src kinase activation, which subsequently phosphorylates its substrate, FAK, and signals to cell proliferation and invasion.

  19. Adenylate cyclase toxin promotes internalisation of integrins and raft components and decreases macrophage adhesion capacity.

    Directory of Open Access Journals (Sweden)

    César Martín

    Full Text Available Bordetella pertussis, the bacterium that causes whooping cough, secretes an adenylate cyclase toxin (ACT that must be post-translationally palmitoylated in the bacterium cytosol to be active. The toxin targets phagocytes expressing the CD11b/CD18 integrin receptor. It delivers a catalytic adenylate cyclase domain into the target cell cytosol producing a rapid increase of intracellular cAMP concentration that suppresses bactericidal functions of the phagocyte. ACT also induces calcium fluxes into target cells. Biochemical, biophysical and cell biology approaches have been applied here to show evidence that ACT and integrin molecules, along with other raft components, are rapidly internalized by the macrophages in a toxin-induced calcium rise-dependent process. The toxin-triggered internalisation events occur through two different routes of entry, chlorpromazine-sensitive receptor-mediated endocytosis and clathrin-independent internalisation, maybe acting in parallel. ACT locates into raft-like domains, and is internalised, also in cells devoid of receptor. Altogether our results suggest that adenylate cyclase toxin, and maybe other homologous pathogenic toxins from the RTX (Repeats in Toxin family to which ACT belongs, may be endowed with an intrinsic capacity to, directly and efficiently, insert into raft-like domains, promoting there its multiple activities. One direct consequence of the integrin removal from the cell surface of the macrophages is the hampering of their adhesion ability, a fundamental property in the immune response of the leukocytes that could be instrumental in the pathogenesis of Bordetella pertussis.

  20. Prednisone inhibits the focal adhesion kinase/receptor activator of NF-κB ligand/mitogen-activated protein kinase signaling pathway in rats with adriamycin-induced nephropathy.

    Science.gov (United States)

    Ye, Minyuan; Zheng, Jing; Chen, Xiaoying; Chen, Xuelan; Wu, Xinhong; Lin, Xiuqin; Liu, Yafang

    2015-11-01

    The aim of the present study was to investigate the mechanisms underlying the effects of prednisone on adriamycin-induced nephritic rat kidney damage via the focal adhesion kinase (FAK)/receptor activator of nuclear factor-κB ligand (RANKL)/mitogen‑activated protein kinase (MAPK) signaling pathway. An adriamycin‑induced nephritic rat model was established to investigate these mechanisms. A total of 30 healthy male Sprague‑Dawley rats were randomly assigned to the normal, model or prednisone group. Samples of urine were collected over the course of 24 h at days 7, 14, and 28, and renal cortex tissue samples were harvested at days 14, and 28 following nephritic rat model establishment. The total urinary protein content was measured by biuret colorimetry. Pathological changes in the kidney tissue samples were observed using an electron microscope. The mRNA expressions levels of FAK, RANKL, p38, extracellular signal‑regulated kinase (ERK), c‑Jun N‑terminal kinase (JNK), and nephrin were then quantified by reverse transcription‑quantitative polymerase chain reaction. In addition, the protein expressions levels of FAK, RANKL, p38, ERK, JNK, phosphorylated (p)‑FAK, p‑ERK, and p‑JNK were quantified by western blotting. As compared with the normal group, the protein expression levels of FAK, RANKL, p-FAK, p38 and p-ERK in the model group were increased. In the prednisone group, the protein expression levels of p-ERK decreased, as compared with the normal group. In the prednisone group, the urinary protein levels, the protein expression levels of FAK, RANKL, p38, p-FAK, p-p38 and the mRNA expression levels of FAK, p38, RANKL, ERK, JNK decreased, as compared with the model group. In the prednisone group, the mRNA and protein expression levels of nephrin and the serum expression levels of RANKL increased, the serum expression levels of osteoprotegerin (OPG) were decreased, as compared with the model group. No significant changes in the protein expression

  1. Neuropeptide-induced androgen independence in prostate cancer cells: roles of nonreceptor tyrosine kinases Etk/Bmx, Src, and focal adhesion kinase.

    Science.gov (United States)

    Lee, L F; Guan, J; Qiu, Y; Kung, H J

    2001-12-01

    The bombesin/gastrin-releasing peptide (GRP) family of neuropeptides has been implicated in various in vitro and in vivo models of human malignancies including prostate cancers. It was previously shown that bombesin and/or neurotensin (NT) acts as a survival and migratory factor(s) for androgen-independent prostate cancers. However, a role in the transition from an androgen-dependent to -refractory state has not been addressed. In this study, we investigate the biological effects and signal pathways of bombesin and NT on LNCaP, a prostate cancer cell line which requires androgen for growth. We show that both neurotrophic factors can induce LNCaP growth in the absence of androgen. Concurrent transactivation of reporter genes driven by the prostate-specific antigen promoter or a promoter carrying an androgen-responsive element (ARE) indicate that growth stimulation is accompanied by androgen receptor (AR) activation. Furthermore, neurotrophic factor-induced gene activation was also present in PC3 cells transfected with the AR but not in the parental line which lacks the AR. Given that bombesin does not directly bind to the AR and is known to engage a G-protein-coupled receptor, we investigated downstream signaling events that could possibly interact with the AR pathway. We found that three nonreceptor tyrosine kinases, focal adhesion kinase (FAK), Src, and Etk/BMX play important parts in this process. Etk/Bmx activation requires FAK and Src and is critical for neurotrophic factor-induced growth, as LNCaP cells transfected with a dominant-negative Etk/BMX fail to respond to bombesin. Etk's activation requires FAK, Src, but not phosphatidylinositol 3-kinase. Likewise, bombesin-induced AR activation is inhibited by the dominant-negative mutant of either Src or FAK. Thus, in addition to defining a new G-protein pathway, this report makes the following points regarding prostate cancer. (i) Neurotrophic factors can activate the AR, thus circumventing the normal growth

  2. Glycogen synthase kinase 3β dictates podocyte motility and focal adhesion turnover by modulating paxillin activity: implications for the protective effect of low-dose lithium in podocytopathy.

    Science.gov (United States)

    Xu, Weiwei; Ge, Yan; Liu, Zhihong; Gong, Rujun

    2014-10-01

    Aberrant focal adhesion turnover is centrally involved in podocyte actin cytoskeleton disorganization and foot process effacement. The structural and dynamic integrity of focal adhesions is orchestrated by multiple cell signaling molecules, including glycogen synthase kinase 3β (GSK3β), a multitasking kinase lately identified as a mediator of kidney injury. However, the role of GSK3β in podocytopathy remains obscure. In doxorubicin (Adriamycin)-injured podocytes, lithium, a GSK3β inhibitor and neuroprotective mood stabilizer, obliterated the accelerated focal adhesion turnover, rectified podocyte hypermotility, and restored actin cytoskeleton integrity. Mechanistically, lithium counteracted the doxorubicin-elicited GSK3β overactivity and the hyperphosphorylation and overactivation of paxillin, a focal adhesion-associated adaptor protein. Moreover, forced expression of a dominant negative kinase dead mutant of GSK3β highly mimicked, whereas ectopic expression of a constitutively active GSK3β mutant abolished, the effect of lithium in doxorubicin-injured podocytes, suggesting that the effect of lithium is mediated, at least in part, through inhibition of GSK3β. Furthermore, paxillin interacted with GSK3β and served as its substrate. In mice with doxorubicin nephropathy, a single low dose of lithium ameliorated proteinuria and glomerulosclerosis. Consistently, lithium therapy abrogated GSK3β overactivity, blunted paxillin hyperphosphorylation, and reinstated actin cytoskeleton integrity in glomeruli associated with an early attenuation of podocyte foot process effacement. Thus, GSK3β-modulated focal adhesion dynamics might serve as a novel therapeutic target for podocytopathy.

  3. Focal Adhesion Kinase-Dependent Role of the Soluble Form of Neurotensin Receptor-3/Sortilin in Colorectal Cancer Cell Dissociation

    Science.gov (United States)

    Béraud-Dufour, Sophie; Devader, Christelle; Massa, Fabienne; Roulot, Morgane; Coppola, Thierry; Mazella, Jean

    2016-01-01

    The aim of the present review is to unravel the mechanisms of action of the soluble form of the neurotensin (NT) receptor-3 (NTSR3), also called Sortilin, in numerous physiopathological processes including cancer development, cardiovascular diseases and depression. Sortilin/NTSR3 is a transmembrane protein thought to exert multiple functions both intracellularly and at the level of the plasma membrane. The Sortilin/NTSR3 extracellular domain is released by shedding from all the cells expressing the protein. Although the existence of the soluble form of Sortilin/NTSR3 (sSortilin/NTSR3) has been evidenced for more than 10 years, the studies focusing on the role of this soluble protein at the mechanistic level remain rare. Numerous cancer cells, including colonic cancer cells, express the receptor family of neurotensin (NT), and particularly Sortilin/NTSR3. This review aims to summarize the functional role of sSortilin/NTSR3 characterized in the colonic cancer cell line HT29. This includes mechanisms involving signaling cascades through focal adhesion kinase (FAK), a key pathway leading to the weakening of cell–cell and cell–extracellular matrix adhesions, a series of events which could be responsible for cancer metastasis. Finally, some future approaches targeting the release of sNTSR3 through the inhibition of matrix metalloproteases (MMPs) are suggested. PMID:27834811

  4. Focal Adhesion Kinase-Dependent Role of the Soluble Form of Neurotensin Receptor-3/Sortilin in Colorectal Cancer Cell Dissociation

    Directory of Open Access Journals (Sweden)

    Sophie Béraud-Dufour

    2016-11-01

    Full Text Available The aim of the present review is to unravel the mechanisms of action of the soluble form of the neurotensin (NT receptor-3 (NTSR3, also called Sortilin, in numerous physiopathological processes including cancer development, cardiovascular diseases and depression. Sortilin/NTSR3 is a transmembrane protein thought to exert multiple functions both intracellularly and at the level of the plasma membrane. The Sortilin/NTSR3 extracellular domain is released by shedding from all the cells expressing the protein. Although the existence of the soluble form of Sortilin/NTSR3 (sSortilin/NTSR3 has been evidenced for more than 10 years, the studies focusing on the role of this soluble protein at the mechanistic level remain rare. Numerous cancer cells, including colonic cancer cells, express the receptor family of neurotensin (NT, and particularly Sortilin/NTSR3. This review aims to summarize the functional role of sSortilin/NTSR3 characterized in the colonic cancer cell line HT29. This includes mechanisms involving signaling cascades through focal adhesion kinase (FAK, a key pathway leading to the weakening of cell–cell and cell–extracellular matrix adhesions, a series of events which could be responsible for cancer metastasis. Finally, some future approaches targeting the release of sNTSR3 through the inhibition of matrix metalloproteases (MMPs are suggested.

  5. Homozygous mutation of focal adhesion kinase in embryonic stem cell derived neurons: normal electrophysiological and morphological properties in vitro

    Directory of Open Access Journals (Sweden)

    Komiyama NH

    2006-06-01

    Full Text Available Abstract Background Genetically manipulated embryonic stem (ES cell derived neurons (ESNs provide a powerful system with which to study the consequences of gene manipulation in mature, synaptically connected neurons in vitro. Here we report a study of focal adhesion kinase (FAK, which has been implicated in synapse formation and regulation of ion channels, using the ESN system to circumvent the embryonic lethality of homozygous FAK mutant mice. Results Mouse ES cells carrying homozygous null mutations (FAK-/- were generated and differentiated in vitro into neurons. FAK-/- ESNs extended axons and dendrites and formed morphologically and electrophysiologically intact synapses. A detailed study of NMDA receptor gated currents and voltage sensitive calcium currents revealed no difference in their magnitude, or modulation by tyrosine kinases. Conclusion FAK does not have an obligatory role in neuronal differentiation, synapse formation or the expression of NMDA receptor or voltage-gated calcium currents under the conditions used in this study. The use of genetically modified ESNs has great potential for rapidly and effectively examining the consequences of neuronal gene manipulation and is complementary to mouse studies.

  6. The glypiated neuronal cell adhesion molecule contactin/F11 complexes with src-family protein tyrosine kinase Fyn.

    Science.gov (United States)

    Zisch, A H; D'Alessandri, L; Amrein, K; Ranscht, B; Winterhalter, K H; Vaughan, L

    1995-06-01

    Glycosyl phosphatidylinositol-anchored glycoproteins of the immunoglobulin superfamily play an important role in the formation of neuronal networks during development. The mechanism whereby neuronal GPI-linked molecules transduce recognition signals remains to be established. Analysis of detergent-resistant immune-complexes reveals that the glypiated neuronal cell adhesion molecule contactin/F11 specifically complexes with the cytoplasmic, nonreceptor type src-family tyrosine kinase Fyn. Antibody-mediated cross-linking of contactin/F11 on embryonic chick neuronal cells leads to an increase of the Fyn-activity coprecipitated with contactin/F11, and elevates phosphorylation of an additional 75/80 K component within the contactin/F11-immune-complex. Additionally, binding of ligands, i.e., contactin/F11-specific antibody or tenascin-R, a natural ligand of contactin/F11, to the surface of HeLa transfectants expressing contactin/F11, causes capping of contactin/F11 and a concomitant change in the distribution of the intracellular kinase Fyn, thus confirming their physical association. This indicates that contactin/F11-mediated signaling requires Fyn.

  7. The Src homology 2 protein Shb promotes cell cycle progression in murine hematopoietic stem cells by regulation of focal adhesion kinase activity

    Energy Technology Data Exchange (ETDEWEB)

    Gustafsson, Karin [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden); Heffner, Garrett; Wenzel, Pamela L.; Curran, Matthew [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Grawé, Jan [Department of Genetics and Pathology, Uppsala University, Uppsala 75185 (Sweden); McKinney-Freeman, Shannon L. [Department of Hematology, St. Jude Children' s Research Hospital, Memphis, TN 38105 (United States); Daley, George Q. [HHMI, Children' s Hospital Boston, Harvard Medical School, Boston, 02115 MA (United States); Welsh, Michael, E-mail: michael.welsh@mcb.uu.se [Department of Medical Cell Biology, Uppsala University, Uppsala 751 23 (Sweden)

    2013-07-15

    The widely expressed adaptor protein Shb has previously been reported to contribute to T cell function due to its association with the T cell receptor and furthermore, several of Shb's known interaction partners are established regulators of blood cell development and function. In addition, Shb deficient embryonic stem cells displayed reduced blood cell colony formation upon differentiation in vitro. The aim of the current study was therefore to explore hematopoietic stem and progenitor cell function in the Shb knockout mouse. Shb deficient bone marrow contained reduced relative numbers of long-term hematopoietic stem cells (LT-HSCs) that exhibited lower proliferation rates. Despite this, Shb knockout LT-HSCs responded promptly by entering the cell cycle in response to genotoxic stress by 5-fluorouracil treatment. In competitive LT-HSC transplantations, Shb null cells initially engrafted as well as the wild-type cells but provided less myeloid expansion over time. Moreover, Shb knockout bone marrow cells exhibited elevated basal activities of focal adhesion kinase/Rac1/p21-activated kinase signaling and reduced responsiveness to Stem Cell Factor stimulation. Consequently, treatment with a focal adhesion kinase inhibitor increased Shb knockout LT-HSC proliferation. The altered signaling characteristics thus provide a plausible mechanistic explanation for the changes in LT-HSC proliferation since these signaling intermediates have all been shown to participate in LT-HSC cell cycle control. In summary, the loss of Shb dependent signaling in bone marrow cells, resulting in elevated focal adhesion kinase activity and reduced proliferative responses in LT-HSCs under steady state hematopoiesis, confers a disadvantage to the maintenance of LT-HSCs over time. -- Highlights: • Shb is an adaptor protein operating downstream of tyrosine kinase receptors. • Shb deficiency reduces hematopoietic stem cell proliferation. • The proliferative effect of Shb occurs via

  8. Deletion of the endothelial Bmx tyrosine kinase decreases tumor angiogenesis and growth.

    Science.gov (United States)

    Holopainen, Tanja; López-Alpuche, Vanessa; Zheng, Wei; Heljasvaara, Ritva; Jones, Dennis; He, Yun; Tvorogov, Denis; D'Amico, Gabriela; Wiener, Zoltan; Andersson, Leif C; Pihlajaniemi, Taina; Min, Wang; Alitalo, Kari

    2012-07-15

    Bmx, [corrected] also known as Etk, is a member of the Tec family of nonreceptor tyrosine kinases. Bmx is expressed mainly in arterial endothelia and in myeloid hematopoietic cells. Bmx regulates ischemia-mediated arteriogenesis and lymphangiogenesis, but its role in tumor angiogenesis is not known. In this study, we characterized the function of Bmx in tumor growth using both Bmx knockout and transgenic mice. Isogenic colon, lung, and melanoma tumor xenotransplants showed reductions in growth and tumor angiogenesis in Bmx gene-deleted ((-/-)) mice, whereas developmental angiogenesis was not affected. In addition, growth of transgenic pancreatic islet carcinomas and intestinal adenomas was also slower in Bmx(-/-) mice. Knockout mice showed high levels of Bmx expression in endothelial cells of tumor-associated and peritumoral arteries. Moreover, endothelial cells lacking Bmx showed impaired phosphorylation of extracellular signal-regulated kinase (Erk) upon VEGF stimulation, indicating that Bmx contributes to the transduction of vascular endothelial growth factor signals. In transgenic mice overexpressing Bmx in epidermal keratinocytes, tumors induced by a two-stage chemical skin carcinogenesis treatment showed increased growth and angiogenesis. Our findings therefore indicate that Bmx activity contributes to tumor angiogenesis and growth.

  9. Long-Term Exposure to High Corticosterone Levels Inducing a Decrease of Adenylate Kinase 1 Activity

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yu'nan; SHEN Jia; SU Hui; HUANG Yufang; XING Dongming; DU Lijun

    2009-01-01

    Corticosterone, a principal glucocorticoid synthesized in the rodent adrenal cortex, can be cumula-tively toxic to hippocampal neurons, the cause of which is not known. The present study determined whether the cytosol adenylate kinase (AK) system was involved in the neuronal damage induced by long-term exposure to high corticosterone levels. We investigated the effects of long-term exposure to high corticosterone levels on AK1 activity, AK1 mRNA expression, and energy levels in cultured hippocampal neurons. The results show that long-term exposure to high corticosterone levels induces a reduction of the cultured hippocampal neuron viability, significantly reduces energy levels, and causes a time-dependant re-duction of the AK1 activity. These findings indicate that changes in the AK system might be the mechanism underlying neuronal damage induced by long-term exposure to high corticosterone levels.

  10. Progesterone receptor isoforms PRA and PRB differentially contribute to breast cancer cell migration through interaction with focal adhesion kinase complexes.

    Science.gov (United States)

    Bellance, Catherine; Khan, Junaid A; Meduri, Geri; Guiochon-Mantel, Anne; Lombès, Marc; Loosfelt, Hugues

    2013-05-01

    Progesterone receptor (PR) and progestins affect mammary tumorigenesis; however, the relative contributions of PR isoforms A and B (PRA and PRB, respectively) in cancer cell migration remains elusive. By using a bi-inducible MDA-MB-231 breast cancer cell line expressing PRA and/or PRB, we analyzed the effect of conditional PR isoform expression. Surprisingly, unliganded PRB but not PRA strongly enhanced cell migration as compared with PR(-) cells. 17,21-Dimethyl-19-norpregna-4,9-dien-3,20-dione (R5020) progestin limited this effect and was counteracted by the antagonist 11β-(4-dimethyl-amino)-phenyl-17β-hydroxy-17-(1-propynyl)-estra-4,9-dien-3-one (RU486). Of importance, PRA coexpression potentiated PRB-mediated migration, whereas PRA alone was ineffective. PR isoforms differentially regulated expressions of major players of cell migration, such as urokinase plasminogen activator (uPA), its inhibitor plasminogen activator inhibitor type 1, uPA receptor (uPAR), and β1-integrin, which affect focal adhesion kinase (FAK) signaling. Moreover, unliganded PRB but not PRA enhanced FAK Tyr397 phosphorylation and colocalized with activated FAK in cell protrusions. Because PRB, as well as PRA, coimmunoprecipitated with FAK, both isoforms can interact with FAK complexes, depending on their respective nucleocytoplasmic trafficking. In addition, FAK degradation was coupled to R5020-dependent turnovers of PRA and PRB. Such an effect of PRB/PRA expression on FAK signaling might thus affect adhesion/motility, underscoring the implication of PR isoforms in breast cancer invasiveness and metastatic evolution with underlying therapeutic outcomes.

  11. Cell invasion by Neisseria meningitidis requires a functional interplay between the focal adhesion kinase, Src and cortactin.

    Directory of Open Access Journals (Sweden)

    Heiko Slanina

    Full Text Available Entry of Neisseria meningitidis (the meningococcus into human brain microvascular endothelial cells (HBMEC is mediated by fibronectin or vitronectin bound to the surface protein Opc forming a bridge to the respective integrins. This interaction leads to cytoskeletal rearrangement and uptake of meningococci. In this study, we determined that the focal adhesion kinase (FAK, which directly associates with integrins, is involved in integrin-mediated internalization of N. meningitidis in HBMEC. Inhibition of FAK activity by the specific FAK inhibitor PF 573882 reduced Opc-mediated invasion of HBMEC more than 90%. Moreover, overexpression of FAK mutants that were either impaired in the kinase activity or were not capable of autophosphorylation or overexpression of the dominant-negative version of FAK (FRNK blocked integrin-mediated internalization of N. meningitidis. Importantly, FAK-deficient fibroblasts were significantly less invaded by N. meningitidis. Furthermore, N. meningitidis induced tyrosine phosphorylation of several host proteins including the FAK/Src complex substrate cortactin. Inhibition of cortactin expression by siRNA silencing and mutation of critical amino acid residues within cortactin, that encompass Arp2/3 association and dynamin binding, significantly reduced meningococcal invasion into eukaryotic cells suggesting that both domains are critical for efficient uptake of N. meningitidis into eukaryotic cells. Together, these results indicate that N. meningitidis exploits the integrin signal pathway for its entry and that FAK mediates the transfer of signals from activated integrins to the cytoskeleton. A cooperative interplay between FAK, Src and cortactin then enables endocytosis of N. meningitidis into host cells.

  12. Focal adhesion kinase activation is required for TNF-α-induced production of matrix metalloproteinase-2 and proinflammatory cytokines in cultured human periodontal ligament fibroblasts.

    Science.gov (United States)

    Zhang, Peng; Li, Ya-jing; Guo, Liu-yun; Wang, Guo-fang; Lu, Ke; Yue, Er-li

    2015-08-01

    Since focal adhesion kinase (FAK) was proposed as a mediator of the inflammatory response, we have investigated the role of this molecule in the release of inflammatory cytokines by cultured human periodontal ligament fibroblasts (HPDLFs), cells that are thought to be important in the patient's response to periodontal infection. Human periodontal ligament fibroblasts were stimulated by tumor necrosis factor alpha (TNF-α) and its effects on interleukin (IL)-6 and IL-8 release were measured by ELISA. Expression of matrix metalloproteinase 2 (MMP-2) protein was analysed by western blotting. The levels of IL6, IL8, and MMP2 mRNA were evaluated by real-time PCR. Tumor necrosis factor alpha dose-dependently induced the phosphorylation of FAK, whereas small interfering FAK (siFAK) inhibited TNF-α-induced FAK phosphorylation. Tumor necrosis factor alpha also stimulated the production of IL-6, IL-8, and MMP-2 in a dose-dependent manner. Knockdown of FAK significantly suppressed TNF-α-induced expression of IL6 and IL8 mRNA and release of IL-6 and IL-8 protein in HPDLFs. Similarly, MMP-2 down-regulation was significantly prevented by siFAK. Our results strongly suggest that knockdown of FAK can decrease the production of TNF-α-induced IL-6, IL-8, and MMP-2 in HPDLFs. These effects may help in understanding the mechanisms that control expression of inflammatory cytokines in the pathogenesis of periodontitis.

  13. Focal Adhesion Kinase-mediated Phosphorylation of Beclin1 Protein Suppresses Cardiomyocyte Autophagy and Initiates Hypertrophic Growth*♦

    Science.gov (United States)

    Cheng, Zhaokang; Zhu, Qiang; Dee, Rachel; Opheim, Zachary; Mack, Christopher P.; Cyr, Douglas M.; Taylor, Joan M.

    2017-01-01

    Autophagy is an evolutionarily conserved intracellular degradation/recycling system that is essential for cellular homeostasis but is dysregulated in a number of diseases, including myocardial hypertrophy. Although it is clear that limiting or accelerating autophagic flux can result in pathological cardiac remodeling, the physiological signaling pathways that fine-tune cardiac autophagy are poorly understood. Herein, we demonstrated that stimulation of cardiomyocytes with phenylephrine (PE), a well known hypertrophic agonist, suppresses autophagy and that activation of focal adhesion kinase (FAK) is necessary for PE-stimulated autophagy suppression and subsequent initiation of hypertrophic growth. Mechanistically, we showed that FAK phosphorylates Beclin1, a core autophagy protein, on Tyr-233 and that this post-translational modification limits Beclin1 association with Atg14L and reduces Beclin1-dependent autophagosome formation. Remarkably, although ectopic expression of wild-type Beclin1 promoted cardiomyocyte atrophy, expression of a Y233E phosphomimetic variant of Beclin1 failed to affect cardiomyocyte size. Moreover, genetic depletion of Beclin1 attenuated PE-mediated/FAK-dependent initiation of myocyte hypertrophy in vivo. Collectively, these findings identify FAK as a novel negative regulator of Beclin1-mediated autophagy and indicate that this pathway can facilitate the promotion of compensatory hypertrophic growth. This novel mechanism to limit Beclin1 activity has important implications for treating a variety of pathologies associated with altered autophagic flux. PMID:27994061

  14. Heat shock protein 90β stabilizes focal adhesion kinase and enhances cell migration and invasion in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Xiangyang [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi 330006 (China); State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Wang, Yao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Liu, Chengmei [State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang, Jiangxi 330047 (China); Lu, Quqin [Department of Biostatistics and Epidemiology, School of Public Health, Nanchang University, Nanchang, Jiangxi 330006 (China); Liu, Tao [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China); Chen, Guoan [Department of Hematology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi 330006 (China); Rao, Hai [Department of Molecular Medicine, University of Texas Health Science Center, San Antonio, TX 78229 (United States); Luo, Shiwen, E-mail: shiwenluo@ncu.edu.cn [Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, 17 Yongwai Street, Donghu District, Nanchang, Jiangxi 330006 (China)

    2014-08-01

    Focal adhesion kinase (FAK) acts as a regulator of cellular signaling and may promote cell spreading, motility, invasion and survival in malignancy. Elevated expression and activity of FAK frequently correlate with tumor cell metastasis and poor prognosis in breast cancer. However, the mechanisms by which the turnover of FAK is regulated remain elusive. Here we report that heat shock protein 90β (HSP90β) interacts with FAK and the middle domain (amino acids 233–620) of HSP90β is mainly responsible for this interaction. Furthermore, we found that HSP90β regulates FAK stability since HSP90β inhibitor 17-AAG triggers FAK ubiquitylation and subsequent proteasome-dependent degradation. Moreover, disrupted FAK-HSP90β interaction induced by 17-AAG contributes to attenuation of tumor cell growth, migration, and invasion. Together, our results reveal how HSP90β regulates FAK stability and identifies a potential therapeutic strategy to breast cancer. - Highlights: • HSP90β protects FAK from degradation by the ubiquitin-proteasome pathway. • Inhibition of HSP90β or FAK attenuates tumorigenesis of breast cancer cells. • Genetic repression of HSP90β or FAK inhibits tumor cell migration and proliferation. • Inhibition of HSP90β or FAK interferes cell invasion and cytoskeleton.

  15. The protein tyrosine kinase inhibitor, genistein, decreases the excitability of capsaicin-sensitive neurons

    Institute of Scientific and Technical Information of China (English)

    L.Liu; FuHui; T.Yang; S.A.Simon

    2004-01-01

    AIM : One of the primary mechanisms by which neurons regulate their excitability is through of ion channel phosphorylafion. Compounds that increase noeiceptor excitability can cause hyporalgesia or allodynia whereas compounds that decrease noeiceptor excitability can be used as analgesics to relieve pain arising from inflammation or trauma. METHODS:

  16. Interleukin-2 induces beta2-integrin-dependent signal transduction involving the focal adhesion kinase-related protein B (fakB)

    DEFF Research Database (Denmark)

    Brockdorff, J; Kanner, S B; Nielsen, M;

    1998-01-01

    experiments indicate that the IL-2-induced 125-kDa phosphotyrosine protein is the focal adhesion kinase-related protein B (fakB). Thus, IL-2 induces strong tyrosine phosphorylation of fakB in beta2-integrin-positive but not in beta2-integrin-negative T cells, and CD18 mAb selectively blocks IL-2-induced fakB......-tyrosine phosphorylation in beta2-integrin-positive T cells. In parallel experiments, IL-2 does not induce or augment tyrosine phosphorylation of p125(FAK). In conclusion, our data indicate that IL-2 induces beta2-integrin-dependent signal transduction events involving the tyrosine kinase substrate fakB....... and a leukocyte adhesion deficiency (LAD) patient. We show that IL-2 induces tyrosine phosphorylation of a 125-kDa protein and homotypic adhesion in beta2 integrin (CD18)-positive but not in beta2-integrin-negative T cells. EDTA, an inhibitor of integrin adhesion, blocks IL-2-induced tyrosine phosphorylation...

  17. Sargaquinoic Acid Inhibits TNF-α-Induced NF-κB Signaling, Thereby Contributing to Decreased Monocyte Adhesion to Human Umbilical Vein Endothelial Cells (HUVECs).

    Science.gov (United States)

    Gwon, Wi-Gyeong; Lee, Bonggi; Joung, Eun-Ji; Choi, Min-Woo; Yoon, Nayoung; Shin, Taisun; Oh, Chul-Woong; Kim, Hyeung-Rak

    2015-10-21

    Sargaquinoic acid (SQA) has been known for its antioxidant and anti-inflammatory properties. This study investigated the effects of SQA isolated from Sargassum serratifolium on the inhibition of tumor necrosis factor (TNF)-α-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). SQA decreased the expression of cell adhesion molecules such as intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as chemotactic cytokines such as interleukin-8 and monocyte chemoattractant protein-1 in TNF-α-treated HUVECs. As a result, SQA prevented monocyte adhesion to TNF-α-induced adhesion. SQA also inhibited TNF-α-induced nuclear factor kappa B (NF-κB) translocation into the nucleus by preventing proteolytic degradation of inhibitor κB-α. Overall, SQA protects against TNF-α-induced vascular inflammation through inhibition of the NF-κB pathway in HUVECs. These data suggest that SQA may be used as a therapeutic agent for vascular inflammatory diseases such as atherosclerosis.

  18. Green Tea Epigallocatechin Gallate Exhibits Anticancer Effect in Human Pancreatic Carcinoma Cells via the Inhibition of Both Focal Adhesion Kinase and Insulin-Like Growth Factor-I Receptor

    Directory of Open Access Journals (Sweden)

    Hoang Anh Vu

    2010-01-01

    Full Text Available The exact molecular mechanism by which epigallocatechin gallate (EGCG suppresses human pancreatic cancer cell proliferation is unclear. We show here that EGCG-treated pancreatic cancer cells AsPC-1 and BxPC-3 decrease cell adhesion ability on micro-pattern dots, accompanied by dephosphorylations of both focal adhesion kinase (FAK and insulin-like growth factor-1 receptor (IGF-1R whereas retained the activations of mitogen-activated protein kinase and mammalian target of rapamycin. The growth of AsPC-1 and BxPC-3 cells can be significantly suppressed by EGCG treatment alone in a dose-dependent manner. At a dose of 100 μM which completely abolishes activations of FAK and IGF-1R, EGCG suppresses more than 50% of cell proliferation without evidence of apoptosis analyzed by PARP cleavage. Finally, the MEK1/2 inhibitor U0126 enhances growth-suppressive effect of EGCG. Our data suggests that blocking FAK and IGF-1R by EGCG could prove valuable for targeted therapy, which can be used in combination with other therapies, for pancreatic cancer.

  19. Loss of cyclin-dependent kinase 5 from parvalbumin interneurons leads to hyperinhibition, decreased anxiety, and memory impairment.

    Science.gov (United States)

    Rudenko, Andrii; Seo, Jinsoo; Hu, Ji; Su, Susan C; de Anda, Froylan Calderon; Durak, Omer; Ericsson, Maria; Carlén, Marie; Tsai, Li-Huei

    2015-02-11

    Perturbations in fast-spiking parvalbumin (PV) interneurons are hypothesized to be a major component of various neuropsychiatric disorders; however, the mechanisms regulating PV interneurons remain mostly unknown. Recently, cyclin-dependent kinase 5 (Cdk5) has been shown to function as a major regulator of synaptic plasticity. Here, we demonstrate that genetic ablation of Cdk5 in PV interneurons in mouse brain leads to an increase in GABAergic neurotransmission and impaired synaptic plasticity. PVCre;fCdk5 mice display a range of behavioral abnormalities, including decreased anxiety and memory impairment. Our results reveal a central role of Cdk5 expressed in PV interneurons in gating inhibitory neurotransmission and underscore the importance of such regulation during behavioral tasks. Our findings suggest that Cdk5 can be considered a promising therapeutic target in a variety of conditions attributed to inhibitory interneuronal dysfunction, such as epilepsy, anxiety disorders, and schizophrenia.

  20. The PI3-kinase delta inhibitor idelalisib (GS-1101) targets integrin-mediated adhesion of chronic lymphocytic leukemia (CLL) cell to endothelial and marrow stromal cells.

    Science.gov (United States)

    Fiorcari, Stefania; Brown, Wells S; McIntyre, Bradley W; Estrov, Zeev; Maffei, Rossana; O'Brien, Susan; Sivina, Mariela; Hoellenriegel, Julia; Wierda, William G; Keating, Michael J; Ding, Wei; Kay, Neil E; Lannutti, Brian J; Marasca, Roberto; Burger, Jan A

    2013-01-01

    CLL cell trafficking between blood and tissue compartments is an integral part of the disease process. Idelalisib, a phosphoinositide 3-kinase delta (PI3Kδ) inhibitor causes rapid lymph node shrinkage, along with an increase in lymphocytosis, prior to inducing objective responses in CLL patients. This characteristic activity presumably is due to CLL cell redistribution from tissues into the blood, but the underlying mechanisms are not fully understood. We therefore analyzed idelalisib effects on CLL cell adhesion to endothelial and bone marrow stromal cells (EC, BMSC). We found that idelalisib inhibited CLL cell adhesion to EC and BMSC under static and shear flow conditions. TNFα-induced VCAM-1 (CD106) expression in supporting layers increased CLL cell adhesion and accentuated the inhibitory effect of idelalisib. Co-culture with EC and BMSC also protected CLL from undergoing apoptosis, and this EC- and BMSC-mediated protection was antagonized by idelalisib. Furthermore, we demonstrate that CLL cell adhesion to EC and VLA-4 (CD49d) resulted in the phosphorylation of Akt, which was sensitive to inhibition by idelalisib. These findings demonstrate that idelalisib interferes with integrin-mediated CLL cell adhesion to EC and BMSC, providing a novel mechanism to explain idelalisib-induced redistribution of CLL cells from tissues into the blood.

  1. The PI3-kinase delta inhibitor idelalisib (GS-1101 targets integrin-mediated adhesion of chronic lymphocytic leukemia (CLL cell to endothelial and marrow stromal cells.

    Directory of Open Access Journals (Sweden)

    Stefania Fiorcari

    Full Text Available CLL cell trafficking between blood and tissue compartments is an integral part of the disease process. Idelalisib, a phosphoinositide 3-kinase delta (PI3Kδ inhibitor causes rapid lymph node shrinkage, along with an increase in lymphocytosis, prior to inducing objective responses in CLL patients. This characteristic activity presumably is due to CLL cell redistribution from tissues into the blood, but the underlying mechanisms are not fully understood. We therefore analyzed idelalisib effects on CLL cell adhesion to endothelial and bone marrow stromal cells (EC, BMSC. We found that idelalisib inhibited CLL cell adhesion to EC and BMSC under static and shear flow conditions. TNFα-induced VCAM-1 (CD106 expression in supporting layers increased CLL cell adhesion and accentuated the inhibitory effect of idelalisib. Co-culture with EC and BMSC also protected CLL from undergoing apoptosis, and this EC- and BMSC-mediated protection was antagonized by idelalisib. Furthermore, we demonstrate that CLL cell adhesion to EC and VLA-4 (CD49d resulted in the phosphorylation of Akt, which was sensitive to inhibition by idelalisib. These findings demonstrate that idelalisib interferes with integrin-mediated CLL cell adhesion to EC and BMSC, providing a novel mechanism to explain idelalisib-induced redistribution of CLL cells from tissues into the blood.

  2. Targeting sphingosine kinase 1 in carcinoma cells decreases proliferation and survival by compromising PKC activity and cytokinesis.

    Directory of Open Access Journals (Sweden)

    Nataliya Kotelevets

    Full Text Available Sphingosine kinases (SK catalyze the phosphorylation of proapoptotic sphingosine to the prosurvival factor sphingosine 1-phosphate (S1P, thereby promoting oncogenic processes. Breast (MDA-MB-231, lung (NCI-H358, and colon (HCT 116 carcinoma cells were transduced with shRNA to downregulate SK-1 expression or treated with a pharmacologic SK-1 inhibitor. The effects of SK-1 targeting were investigated by measuring the level of intracellular sphingosine, the activity of protein kinase C (PKC and cell cycle regulators, and the mitotic index. Functional assays included measurement of cell proliferation, colony formation, apoptosis, and cell cycle analysis. Downregulation of SK-1 or its pharmacologic inhibition increased intracellular sphingosine and decreased PKC activity as shown by reduced phosphorylation of PKC substrates. In MDA-MB-231 cells this effect was most pronounced and reduced cell proliferation and colony formation, which could be mimicked using exogenous sphingosine or the PKC inhibitor RO 31-8220. SK-1 downregulation in MDA-MB-231 cells increased the number of cells with 4N and 8N DNA content, and similar effects were observed upon treatment with sphingosine or inhibitors of SK-1 or PKC. Examination of cell cycle regulators unveiled decreased cdc2 activity and expression of Chk1, which may compromise spindle checkpoint function and cytokinesis. Indeed, SK-1 kd cells entered mitosis but failed to divide, and in the presence of taxol also failed to sustain mitotic arrest, resulting in further increased endoreduplication and apoptosis. Our findings delineate an intriguing link between SK-1, PKC and components of the cell cycle machinery, which underlines the significance of SK-1 as a target for cancer therapy.

  3. A novel type 3 secretion system effector, YspI of Yersinia enterocolitica, induces cell paralysis by reducing total focal adhesion kinase.

    Science.gov (United States)

    LeGrand, Karen; Matsumoto, Hiroyuki; Young, Glenn M

    2015-05-01

    Some of the world's most important diseases are caused by bacterial pathogens that deliver toxic effector proteins directly into eukaryotic cells using type III secretion systems. The myriad of pathological outcomes caused by these pathogens is determined, in part, by the manipulation of host cell physiology due to the specific activities of individual effectors among the unique suite each pathogen employs. YspI was found to be an effector, delivered by Yersinia enterocolitica Biovar 1B, that inhibits host cell motility. The action of YspI comes about through its specific interaction with focal adhesion kinase, FAK, which is a fulcrum of focal adhesion complexes for controlling cellular motility. The interaction was defined by a specific domain of YspI that bound to the FAK kinase domain. Further examination revealed that YspI-FAK interaction leads to a reduction of FAK steady-state levels without altering its phosphorylation state. This collection of observations and results showed YspI displays unique functionality by targeting the key regulator of focal adhesion complexes to inhibit cellular movement.

  4. Inhibition on Apoptosis Induced by Elevated Hydrostatic Pressure in Retinal Ganglion Cell-5 via Laminin Upregulating β1-integrin/Focal Adhesion Kinase/Protein Kinase B Signaling Pathway

    Institute of Scientific and Technical Information of China (English)

    Yi Li; Yan-Ming Chen; Ming-Ming Sun; Xiao-Dan Guo; Ya-Chen Wang; Zhong-Zhi Zhang

    2016-01-01

    Background:Glaucoma is a progressive optic neuropathy characterized by degeneration of neurons due to loss of retinal ganglion cells (RGCs).High intraocular pressure (HIOP),the main risk factor,causes the optic nerve damage.However,the precise mechanism of HIOP-induced RGC death is not yet completely understood.This study was conducted to determine apoptosis of RGC-5 cells induced by elevated hydrostatic pressures,explore whether laminin is associated with apoptosis under pressure,whether laminin can protect RGCs from apoptosis and affirm the mechanism that regulates the process of RGCs survival.Methods:RGC-5 cells were exposed to 0,20,40,and 60 mmHg in a pressurized incubator for 6,12,and 24 h,respectively.The effect of elevated hydrostatic pressure on RGC-5 cells was measured by Annexin V-fluorescein isothiocyanate/propidium iodide staining,3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay,and Western blotting of cleaved caspase-3 protein.Location and expression oflaminin were detected by immunofluorescence.The expression of β 1-integrin,phosphorylation of focal adhesion kinase (FAK) and protein kinase B (PKB,or AKT) were investigated with real-time polymerase chain reaction and Western blotting analysis.Results:Elevated hydrostatic pressure induced apoptosis in cultured RGC-5 cells.Pressure with 40 mmHg for 24 h induced a maximum apoptosis.Laminin was declined in RGC-5 cells after exposing to 40 mmHg for 24 h.After pretreating with laminin,RGC-5 cells survived from elevated pressure.Furthermore,β1-integrin and phosphorylation of FAK and AKT were increased compared to 40 mmHg group.Conclusions:The data show apoptosis tendency of RGC-5 cells with elevated hydrostatic pressure.Laminin can protect RGC-5 cells against high pressure via β 1-integrin/FAK/AKT signaling pathway.These results suggest that the decreased laminin of RGC-5 cells might be responsible for apoptosis induced by elevated hydrostatic pressure,and laminin or activating β1

  5. Protein kinase C inhibition attenuates vascular ETB receptor upregulation and decreases brain damage after cerebral ischemia in rat

    Directory of Open Access Journals (Sweden)

    Vikman Petter

    2007-01-01

    Full Text Available Abstract Background Protein kinase C (PKC is known to be involved in the pathophysiology of experimental cerebral ischemia. We have previously shown that after transient middle cerebral artery occlusion, there is an upregulation of endothelin receptors in the ipsilateral middle cerebral artery. The present study aimed to examine the effect of the PKC inhibitor Ro-32-0432 on endothelin receptor upregulation, infarct volume and neurology outcome after middle cerebral artery occlusion in rat. Results At 24 hours after transient middle cerebral artery occlusion (MCAO, the contractile endothelin B receptor mediated response and the endothelin B receptor protein expression were upregulated in the ipsilateral but not the contralateral middle cerebral artery. In Ro-32-0432 treated rats, the upregulated endothelin receptor response was attenuated. Furthermore, Ro-32-0432 treatment decreased the ischemic brain damage significantly and improved neurological scores. Immunohistochemistry showed fainter staining of endothelin B receptor protein in the smooth muscle cells of the ipsilateral middle cerebral artery of Ro-32-0432 treated rats compared to control. Conclusion The results suggest that treatment with Ro-32-0432 in ischemic stroke decreases the ischemic infarction area, neurological symptoms and associated endothelin B receptor upregulation. This provides a new perspective on possible mechanisms of actions of PKC inhibition in cerebral ischemia.

  6. Notch signaling mediates the age-associated decrease in adhesion of germline stem cells to the niche.

    Science.gov (United States)

    Tseng, Chen-Yuan; Kao, Shih-Han; Wan, Chih-Ling; Cho, Yueh; Tung, Shu-Yun; Hsu, Hwei-Jan

    2014-12-01

    Stem cells have an innate ability to occupy their stem cell niche, which in turn, is optimized to house stem cells. Organ aging is associated with reduced stem cell occupancy in the niche, but the mechanisms involved are poorly understood. Here, we report that Notch signaling is increased with age in Drosophila female germline stem cells (GSCs), and this results in their removal from the niche. Clonal analysis revealed that GSCs with low levels of Notch signaling exhibit increased adhesiveness to the niche, thereby out-competing their neighbors with higher levels of Notch; adhesiveness is altered through regulation of E-cadherin expression. Experimental enhancement of Notch signaling in GSCs hastens their age-dependent loss from the niche, and such loss is at least partially mediated by Sex lethal. However, disruption of Notch signaling in GSCs does not delay GSC loss during aging, and nor does it affect BMP signaling, which promotes self-renewal of GSCs. Finally, we show that in contrast to GSCs, Notch activation in the niche (which maintains niche integrity, and thus mediates GSC retention) is reduced with age, indicating that Notch signaling regulates GSC niche occupancy both intrinsically and extrinsically. Our findings expose a novel role of Notch signaling in controlling GSC-niche adhesion in response to aging, and are also of relevance to metastatic cancer cells, in which Notch signaling suppresses cell adhesion.

  7. The selective adhesion molecule inhibitor Natalizumab decreases multiple myeloma cell growth in the bone marrow microenvironment: therapeutic implications.

    Science.gov (United States)

    Podar, Klaus; Zimmerhackl, Alexander; Fulciniti, Mariateresa; Tonon, Giovanni; Hainz, Ursula; Tai, Yu-Tzu; Vallet, Sonia; Halama, Niels; Jäger, Dirk; Olson, Dian L; Sattler, Martin; Chauhan, Dharminder; Anderson, Kenneth C

    2011-11-01

    Recent advances regarding the introduction of anti-adhesion strategies as a novel therapeutic concept in oncology hold great promise. Here we evaluated the therapeutic potential of the new-in-class-molecule selective-adhesion-molecule (SAM) inhibitor Natalizumab, a recombinant humanized IgG4 monoclonal antibody, which binds integrin-α4, in multiple myeloma (MM). Natalizumab, but not a control antibody, inhibited adhesion of MM cells to non-cellular and cellular components of the microenvironment as well as disrupted the binding of already adherent MM cells. Consequently, Natalizumab blocked both the proliferative effect of MM-bone marrow (BM) stromal cell interaction on tumour cells, and vascular endothelial growth factor (VEGF)-induced angiogenesis in the BM milieu. Moreover, Natalizumab also blocked VEGF- and insulin-like growth factor 1 (IGF-1)-induced signalling sequelae triggering MM cell migration. In agreement with our in vitro results, Natalizumab inhibited tumour growth, VEGF secretion, and angiogenesis in a human severe combined immunodeficiency murine model of human MM in the human BM microenvironment. Importantly, Natalizumab not only blocked tumour cell adhesion, but also chemosensitized MM cells to bortezomib, in an in vitro therapeutically representative human MM-stroma cell co-culture system model. Our data therefore provide the rationale for the clinical evaluation of Natalizumab, preferably in combination with novel agents (e.g. bortezomib) to enhance MM cytotoxicity and improve patient outcome.

  8. Notch signaling mediates the age-associated decrease in adhesion of germline stem cells to the niche.

    Directory of Open Access Journals (Sweden)

    Chen-Yuan Tseng

    2014-12-01

    Full Text Available Stem cells have an innate ability to occupy their stem cell niche, which in turn, is optimized to house stem cells. Organ aging is associated with reduced stem cell occupancy in the niche, but the mechanisms involved are poorly understood. Here, we report that Notch signaling is increased with age in Drosophila female germline stem cells (GSCs, and this results in their removal from the niche. Clonal analysis revealed that GSCs with low levels of Notch signaling exhibit increased adhesiveness to the niche, thereby out-competing their neighbors with higher levels of Notch; adhesiveness is altered through regulation of E-cadherin expression. Experimental enhancement of Notch signaling in GSCs hastens their age-dependent loss from the niche, and such loss is at least partially mediated by Sex lethal. However, disruption of Notch signaling in GSCs does not delay GSC loss during aging, and nor does it affect BMP signaling, which promotes self-renewal of GSCs. Finally, we show that in contrast to GSCs, Notch activation in the niche (which maintains niche integrity, and thus mediates GSC retention is reduced with age, indicating that Notch signaling regulates GSC niche occupancy both intrinsically and extrinsically. Our findings expose a novel role of Notch signaling in controlling GSC-niche adhesion in response to aging, and are also of relevance to metastatic cancer cells, in which Notch signaling suppresses cell adhesion.

  9. Yes-mediated phosphorylation of focal adhesion kinase at tyrosine 861 increases metastatic potential of prostate cancer cells.

    Science.gov (United States)

    Chatterji, Tanushree; Varkaris, Andreas S; Parikh, Nila U; Song, Jian H; Cheng, Chien-Jui; Schweppe, Rebecca E; Alexander, Stephanie; Davis, John W; Troncoso, Patricia; Friedl, Peter; Kuang, Jian; Lin, Sue-Hwa; Gallick, Gary E

    2015-04-30

    To study the role of FAK signaling complexes in promoting metastatic properties of prostate cancer (PCa) cells, we selected stable, highly migratory variants, termed PC3 Mig-3 and DU145 Mig-3, from two well-characterized PCa cell lines, PC3 and DU145. These variants were not only increased migration and invasion in vitro, but were also more metastatic to lymph nodes following intraprostatic injection into nude mice. Both PC3 Mig-3 and DU145 Mig-3 were specifically increased in phosphorylation of FAK Y861. We therefore examined potential alterations in Src family kinases responsible for FAK phosphorylation and determined only Yes expression was increased. Overexpression of Yes in PC3 parental cells and src-/-fyn-/-yes-/- fibroblasts selectively increased FAK Y861 phosphorylation, and increased migration. Knockdown of Yes in PC3 Mig-3 cells decreased migration and decreased lymph node metastasis following orthotopic implantation of into nude mice. In human specimens, Yes expression was increased in lymph node metastases relative to paired primary tumors from the same patient, and increased pFAK Y861 expression in lymph node metastases correlated with poor prognosis. These results demonstrate a unique role for Yes in phosphorylation of FAK and in promoting PCa metastasis. Therefore, phosphorylated FAK Y861 and increased Yes expression may be predictive markers for PCa metastasis.

  10. Triomics Analysis of Imatinib-Treated Myeloma Cells Connects Kinase Inhibition to RNA Processing and Decreased Lipid Biosynthesis.

    Science.gov (United States)

    Breitkopf, Susanne B; Yuan, Min; Helenius, Katja P; Lyssiotis, Costas A; Asara, John M

    2015-11-03

    The combination of metabolomics, lipidomics, and phosphoproteomics that incorporates triple stable isotope labeling by amino acids in cell culture (SILAC) protein labeling, as well as (13)C in vivo metabolite labeling, was demonstrated on BCR-ABL-positive H929 multiple myeloma cells. From 11 880 phosphorylation sites, we confirm that H929 cells are primarily signaling through the BCR-ABL-ERK pathway, and we show that imatinib treatment not only downregulates phosphosites in this pathway but also upregulates phosphosites on proteins involved in RNA expression. Metabolomics analyses reveal that BCR-ABL-ERK signaling in H929 cells drives the pentose phosphate pathway (PPP) and RNA biosynthesis, where pathway inhibition via imatinib results in marked PPP impairment and an accumulation of RNA nucleotides and negative regulation of mRNA. Lipidomics data also show an overall reduction in lipid biosynthesis and fatty acid incorporation with a significant decrease in lysophospholipids. RNA immunoprecipitation studies confirm that RNA degradation is inhibited with short imatinib treatment and transcription is inhibited upon long imatinib treatment, validating the triomics results. These data show the utility of combining mass spectrometry-based "-omics" technologies and reveals that kinase inhibitors may not only downregulate phosphorylation of their targets but also induce metabolic events via increased phosphorylation of other cellular components.

  11. The Natural Stilbenoid Piceatannol Decreases Activity and Accelerates Apoptosis of Human Neutrophils: Involvement of Protein Kinase C

    Directory of Open Access Journals (Sweden)

    Viera Jancinova

    2013-01-01

    Full Text Available Neutrophils are able to release cytotoxic substances and inflammatory mediators, which, along with their delayed apoptosis, have a potential to maintain permanent inflammation. Therefore, treatment of diseases associated with chronic inflammation should be focused on neutrophils; formation of reactive oxygen species and apoptosis of these cells represent two promising targets for pharmacological intervention. Piceatannol, a naturally occurring stilbenoid, has the ability to reduce the toxic action of neutrophils. This substance decreased the amount of oxidants produced by neutrophils both extra- and intracellularly. Radicals formed within neutrophils (fulfilling a regulatory role were reduced to a lesser extent than extracellular oxidants, potentially dangerous for host tissues. Moreover, piceatannol did not affect the phosphorylation of p40phox—a component of NADPH oxidase, responsible for the assembly of functional oxidase in intracellular (granular membranes. The stilbenoid tested elevated the percentage of early apoptotic neutrophils, inhibited the activity of protein kinase C (PKC—the main regulatory enzyme in neutrophils, and reduced phosphorylation of PKC isoforms α, βII, and δ on their catalytic region. The results indicated that piceatannol may be useful as a complementary medicine in states associated with persisting neutrophil activation and with oxidative damage of tissues.

  12. Roles of phosphatidylinositol 3-kinase and NF-kappaB in human cytomegalovirus-mediated monocyte diapedesis and adhesion: strategy for viral persistence.

    Science.gov (United States)

    Smith, M Shane; Bivins-Smith, Elizabeth R; Tilley, A Michael; Bentz, Gretchen L; Chan, Gary; Minard, Jessica; Yurochko, Andrew D

    2007-07-01

    Infected peripheral blood monocytes are proposed to play a key role in the hematogenous dissemination of human cytomegalovirus (HCMV) to tissues, a critical step in the establishment of HCMV persistence and the development of HCMV-associated diseases. We recently provided evidence for a unique strategy involved in viral dissemination: HCMV infection of primary human monocytes promotes their transendothelial migration and differentiation into proinflammatory macrophages permissive for the replication of the original input virus. To decipher the mechanism of hematogenous spread, we focused on the viral dysregulation of early cellular processes involved in transendothelial migration. Here, we present evidence that both phosphatidylinositol 3-kinase [PI(3)K] and NF-kappaB activities were crucial for the HCMV induction of monocyte motility and firm adhesion to endothelial cells. We found that the beta(1) integrins, the beta(2) integrins, intracellular adhesion molecule 1 (ICAM-1), and ICAM-3 were upregulated following HCMV infection and that they played a key role in the firm adhesion of infected monocytes to the endothelium. The viral regulation of adhesion molecule expression is complex, with PI(3)K and NF-kappaB affecting the expression of each adhesion molecule at different stages of the expression cascade. Our data demonstrate key roles for PI(3)K and NF-kappaB signaling in the HCMV-induced cellular changes in monocytes and identify the biological rationale for the activation of these pathways in infected monocytes, which together suggest a mechanism for how HCMV promotes viral spread to and persistence within host organs.

  13. PTH stimulated growth and decreased Col-X deposition are phosphotidylinositol-3,4,5 triphosphate kinase and mitogen activating protein kinase dependent in avian sterna.

    Science.gov (United States)

    Harrington, Erik Kern; Coon, David J; Kern, Matthew F; Svoboda, Kathy K H

    2010-02-01

    Type X collagen (Col-X) deposition is a marker of terminal differentiation during chondrogenesis, in addition to appositional growth and apoptosis. The parathyroid hormone/parathyroid hormone related peptide (PTH/PTHrP) receptor, or PPR, is a G-Protein coupled receptor (GPCR), which activates several downstream pathways, moderating chondrocyte differentiation, including suppression of Col-X deposition. An Avian sterna model was used to analyze the PPR GPCR downstream kinase role in growth rate and extracellular matrix (ECM) including Col-II, IX, and X. Phosphatidylinositol kinase (PI3K), mitogen activating protein kinase (MAPK) and protein kinase A (PKA) were inhibited with specific established inhibitors LY294002, PD98059, and H89, respectively to test the hypothesis that they could reverse/inhibit the PTH/PTHrP pathway. Excised E14 chick sterna were PTH treated with or without an inhibitor and compared to controls. Sternal length was measured every 24 hr. Cultured sterna were immuno-stained using specific antibodies for Col-II, IX, or X and examined via confocal microscopy. Increased growth in PTH-treated sterna was MAPK, PI3K, and PKA dose dependent, suggesting growth was regulated through multiple pathways. Col-X deposition was rescued in PTH-treated sterna in the presence of PI3K or MAPK inhibitors, but not with the PKA inhibitor. All three inhibitors moderately disrupted Col-II and Col-IX deposition. These results suggest that PTH can activate multiple pathways during chondrocyte differentiation.

  14. Non-small-cell lung cancer cells combat epidermal growth factor receptor tyrosine kinase inhibition through immediate adhesion-related responses

    Directory of Open Access Journals (Sweden)

    Wang HY

    2016-05-01

    Full Text Available Hsian-Yu Wang,1,2 Min-Kung Hsu,3,4 Kai-Hsuan Wang,1 Ching-Ping Tseng,2,4 Feng-Chi Chen,3,4 John T-A Hsu1,4 1Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes (NHRI, Zhunan, Miaoli County, 2Institute of Molecular Medicine and Bioengineering, National Chiao Tung University (NCTU, Hsinchu, 3Division of Biostatistics and Bioinformatics, Institute of Population Health Sciences, National Health Research Institutes (NHRI, Zhunan, Miaoli County, 4Department of Biological Science and Technology, National Chiao Tung University (NCTU, Hsinchu, Taiwan, Republic of China Background: Epidermal growth factor receptor (EGFR tyrosine kinase inhibitors (TKIs, such as gefitinib, erlotinib, and afatinib, have greatly improved treatment efficacy in non-small cell lung cancer (NSCLC patients with drug-sensitive EGFR mutations. However, in some TKI responders, the benefits of such targeted therapies are limited by the rapid development of resistance, and strategies to overcome this resistance are urgently needed. Studies of drug resistance in cancer cells typically involve long term in vitro induction to obtain stably acquired drug-resistant cells followed by elucidation of resistance mechanisms, but the immediate responses of cancer cells upon drug treatment have been ignored. The aim of this study was to investigate the immediate responses of NSCLC cells upon treatment with EGFR TKIs.Results: Both NSCLC cells, ie, PC9 and H1975, showed immediate enhanced adhesion-related responses as an apoptosis-countering mechanism upon first-time TKI treatment. By gene expression and pathway analysis, adhesion-related pathways were enriched in gefitinib-treated PC9 cells. Pathway inhibition by small-hairpin RNAs or small-molecule drugs revealed that within hours of EGFR TKI treatment, NSCLC cells used adhesion-related responses to combat the drugs. Importantly, we show here that the Src family inhibitor, dasatinib, dramatically inhibits

  15. Predictors of Left Ventricle Remodeling: Combined Plasma B-type Natriuretic Peptide Decreasing Ratio and Peak Creatine Kinase-MB.

    Science.gov (United States)

    Hsu, Jen-Te; Chung, Chang-Min; Chu, Chi-Ming; Lin, Yu-Shen; Pan, Kuo-Li; Chang, Jung-Jung; Wang, Po-Chang; Chang, Shih-Tai; Yang, Teng-Yao; Jang, Shih-Jung; Yang, Tsung-Han; Hsiao, Ju-Feng

    2017-01-01

    Background: Previous studies reported that patients who had an acute myocardial infarction (AMI) have found that measuring B-type natriuretic peptide (BNP) during the subacute phase of left ventricular (LV) remodeling can predict the possible course of LV remodeling. This study assessed the use of serial BNP serum levels combined with early creatine kinase-MB (CK-MB) to predict the development of significant LV remodeling in AMI patients. Methods: Nighty-seven patients with new onset AMI were assessed using serial echocardiographic studies and serial measurements of BNP levels, both performed on day-2 (BNP1), day-7 (BNP2), day-90 (BNP3), and day-180 (BNP4) after admission. LV remodeling was defined as >20% increase in biplane LV end-diastolic volume on day-180 compared to baseline (day-2). Results: Patients were divided into LV remodeling [LVR(+)] and non LV remodeling [LVR(-)] groups. No first-week BNP level was found to predict remodeling. However, the two groups had significantly different day-90 BNP level (208.1 ± 263.7 pg/ml vs. 82.4 ± 153.7 pg/ml, P = 0.039) and significantly different 3-month BNP decrease ratios ( R BNP13) (14.4 ± 92.2% vs. 69.4 ± 25.9%, P remodeling. Additionally, combining peak CK-MB and R BNP13 offered an excellent discrimination for half-year remodeling when assessed by ROC curve (AUC = 0.818, P remodeling. The early peak CK-MB additionally offered an incremental power to the predictions derived from serial BNP examinations.

  16. The direct effect of Focal Adhesion Kinase (FAK, dominant-negative FAK, FAK-CD and FAK siRNA on gene expression and human MCF-7 breast cancer cell tumorigenesis

    Directory of Open Access Journals (Sweden)

    Zhang Li

    2009-08-01

    Full Text Available Abstract Background Focal adhesion kinase (FAK is a non-receptor tyrosine kinase that plays an important role in survival signaling. FAK has been shown to be overexpressed in breast cancer tumors at early stages of tumorigenesis. Methods To study the direct effect of FAK on breast tumorigenesis, we developed Tet-ON (tetracycline-inducible system of MCF-7 breast cancer cells stably transfected with FAK or dominant-negative, C-terminal domain of FAK (FAK-CD, and also FAKsiRNA with silenced FAK MCF-7 stable cell line. Increased expression of FAK in isogenic Tet-inducible MCF-7 cells caused increased cell growth, adhesion and soft agar colony formation in vitro, while expression of dominant-negative FAK inhibitor caused inhibition of these cellular processes. To study the role of induced FAK and FAK-CD in vivo, we inoculated these Tet-inducible cells in nude mice to generate tumors in the presence or absence of doxycycline in the drinking water. FAKsiRNA-MCF-7 cells were also injected into nude mice to generate xenograft tumors. Results Induction of FAK resulted in significant increased tumorigenesis, while induced FAK-CD resulted in decreased tumorigenesis. Taq Man Low Density Array assay demonstrated specific induction of FAKmRNA in MCF-7-Tet-ON-FAK cells. DMP1, encoding cyclin D binding myb-like protein 1 was one of the genes specifically affected by Tet-inducible FAK or FAK-CD in breast xenograft tumors. In addition, silencing of FAK in MCF-7 cells with FAK siRNA caused increased cell rounding, decreased cell viability in vitro and inhibited tumorigenesis in vivo. Importantly, Affymetrix microarray gene profiling analysis using Human Genome U133A GeneChips revealed >4300 genes, known to be involved in apoptosis, cell cycle, and adhesion that were significantly down- or up-regulated (p Conclusion Thus, these data for the first time demonstrate the direct effect of FAK expression and function on MCF-7 breast cancer tumorigenesis in vivo and reveal

  17. Predictors of Left Ventricle Remodeling: Combined Plasma B-type Natriuretic Peptide Decreasing Ratio and Peak Creatine Kinase-MB

    Science.gov (United States)

    Hsu, Jen-Te; Chung, Chang-Min; Chu, Chi-Ming; Lin, Yu-Shen; Pan, Kuo-Li; Chang, Jung-Jung; Wang, Po-Chang; Chang, Shih-Tai; Yang, Teng-Yao; Jang, Shih-Jung; Yang, Tsung-Han; Hsiao, Ju-Feng

    2017-01-01

    Background: Previous studies reported that patients who had an acute myocardial infarction (AMI) have found that measuring B-type natriuretic peptide (BNP) during the subacute phase of left ventricular (LV) remodeling can predict the possible course of LV remodeling. This study assessed the use of serial BNP serum levels combined with early creatine kinase-MB (CK-MB) to predict the development of significant LV remodeling in AMI patients. Methods: Nighty-seven patients with new onset AMI were assessed using serial echocardiographic studies and serial measurements of BNP levels, both performed on day-2 (BNP1), day-7 (BNP2), day-90 (BNP3), and day-180 (BNP4) after admission. LV remodeling was defined as >20% increase in biplane LV end-diastolic volume on day-180 compared to baseline (day-2). Results: Patients were divided into LV remodeling [LVR(+)] and non LV remodeling [LVR(-)] groups. No first-week BNP level was found to predict remodeling. However, the two groups had significantly different day-90 BNP level (208.1 ± 263.7 pg/ml vs. 82.4 ± 153.7 pg/ml, P = 0.039) and significantly different 3-month BNP decrease ratios (RBNP13) (14.4 ± 92.2% vs. 69.4 ± 25.9%, P < 0.001). The appropriate cut-off value for RBNP13 was 53.2% (AUC = 0.764, P < 0.001). Early peak CK-MB (cut-off 48.2 ng/ml; AUC = 0.672; P = 0.014) was another independent predictor of remodeling. Additionally, combining peak CK-MB and RBNP13 offered an excellent discrimination for half-year remodeling when assessed by ROC curve (AUC = 0.818, P < 0.001). Conclusion: RBNP13 is a significant independent predictor of 6-month LV remodeling. The early peak CK-MB additionally offered an incremental power to the predictions derived from serial BNP examinations. PMID:28138312

  18. Neural cell adhesion molecule-stimulated neurite outgrowth depends on activation of protein kinase C and the Ras-mitogen-activated protein kinase pathway

    DEFF Research Database (Denmark)

    Kolkova, K; Novitskaya, V; Pedersen, N;

    2000-01-01

    , inhibitors of the nonreceptor tyrosine kinase p59(fyn), PLC, PKC and MEK and an activator of PKC, phorbol-12-myristate-13-acetate (PMA). MEK2 transfection rescued cells treated with all inhibitors. The same was found for PMA treatment, except when cells concomitantly were treated with the MEK inhibitor....... Arachidonic acid rescued cells treated with antibodies to the FGF receptor or the PLC inhibitor, but not cells in which the activity of PKC, p59(fyn), FAK, Ras, or MEK was inhibited. Interaction of NCAM with a synthetic NCAM peptide ligand, known to induce neurite outgrowth, was shown to stimulate...

  19. The relative roles of collagen adhesive receptor DDR2 activation and matrix stiffness on the downregulation of focal adhesion kinase in vascular smooth muscle cells.

    Science.gov (United States)

    Bhadriraju, Kiran; Chung, Koo-Hyun; Spurlin, Tighe A; Haynes, Ross J; Elliott, John T; Plant, Anne L

    2009-12-01

    Cells within tissues derive mechanical anchorage and specific molecular signals from the insoluble extracellular matrix (ECM) that surrounds them. Understanding the role of different cues that extracellular matrices provide cells is critical for controlling and predicting cell response to scaffolding materials. Using an engineered extracellular matrix of Type I collagen we examined how the stiffness, supramolecular structure, and glycosylation of collagen matrices influence the protein levels of cellular FAK and the activation of myosin II. Our results show that (1) cellular FAK is downregulated on collagen fibrils, but not on a non-fibrillar monolayer of collagen, (2) the downregulation of FAK is independent of the stiffness of the collagen fibrils, and (3) FAK levels are correlated with levels of tyrosine phosphorylation of the collagen adhesion receptor DDR2. Further, siRNA depletion of DDR2 blocks FAK downregulation. Our results suggest that the collagen receptor DDR2 is involved in the regulation of FAK levels in vSMC adhered to Type I collagen matrices, and that regulation of FAK levels in these cells appears to be independent of matrix stiffness.

  20. Osthole Suppresses the Migratory Ability of Human Glioblastoma Multiforme Cells via Inhibition of Focal Adhesion Kinase-Mediated Matrix Metalloproteinase-13 Expression

    Directory of Open Access Journals (Sweden)

    Cheng-Fang Tsai

    2014-03-01

    Full Text Available Glioblastoma multiforme (GBM is the most common type of primary and malignant tumor occurring in the adult central nervous system. GBM often invades surrounding regions of the brain during its early stages, making successful treatment difficult. Osthole, an active constituent isolated from the dried C. monnieri fruit, has been shown to suppress tumor migration and invasion. However, the effects of osthole in human GBM are largely unknown. Focal adhesion kinase (FAK is important for the metastasis of cancer cells. Results from this study show that osthole can not only induce cell death but also inhibit phosphorylation of FAK in human GBM cells. Results from this study show that incubating GBM cells with osthole reduces matrix metalloproteinase (MMP-13 expression and cell motility, as assessed by cell transwell and wound healing assays. This study also provides evidence supporting the potential of osthole in reducing FAK activation, MMP-13 expression, and cell motility in human GBM cells.

  1. Decrease of breast cancer cell invasiveness by sodium phenylacetate (NaPa) is associated with an increased expression of adhesive molecules.

    Science.gov (United States)

    Vasse, M; Thibout, D; Paysant, J; Legrand, E; Soria, C; Crépin, M

    2001-03-23

    Sodium phenylacetate (NaPa), a non-toxic phenylalanine metabolite, has been shown to induce in vivo and in vitro cytostatic and antiproliferative effects on various cell types. In this work, we analysed the effect of NaPa on the invasiveness of breast cancer cell (MDA-MB-231, MCF-7 and MCF-7 ras). Using the highly invasive breast cancer cell line MDA-MB-231, we demonstrated that an 18-hour incubation with NaPa strongly inhibits the cell invasiveness through Matrigel (86% inhibition at 20 mM of NaPa). As cell invasiveness is greatly influenced by the expression of urokinase (u-PA) and its cell surface receptor (u-PAR) as well as the secretion of matrix metalloproteinases (MMP), we tested the effect of NaPa on these parameters. An 18-hour incubation with NaPa did not modify u-PA expression, either on MDA-MB-231 or on MCF-7 and MCF-7 ras cell lines, and induced a small u-PA decrease after 3 days of treatment of MDA-MB-321 with NaPa. In contrast, an 18 h incubation of MDA-MB-231 increased the expression of u-PAR and the secretion of MMP-9. As u-PAR is a ligand for vitronectin, a composant of the extracellular matrix, these data could explain the increased adhesion of MDA-MB-231 to vitronectin, while cell adhesivity of MCF-7 and MCF-7 ras was unmodified by NaPa treatment. NaPa induced also an increased expression of both Lymphocyte Function-Associated-1 (LFA-1) and Intercellular Adhesion Molecule-1 (ICAM-1), which was obvious from 18 hour incubation with NaPa for the MDA-MB-231 cells, but was delayed (3 days) for MCF-7 and MCF-7 ras. Only neutralizing antibodies against LFA-1 reversed the decreased invasiveness of NaPa-treated cells. Therefore we can conclude that the strong inhibition of MDA-MB-231 invasiveness is not due to a decrease in proteases involved in cell migration (u-PA and MMP) but could be related both to the modification of cell structure and an increased expression of adhesion molecules such as u-PAR and LFA-1.

  2. Research progress on focal adhesion kinase in malignant tumors%FAK 在恶性肿瘤中的研究进展

    Institute of Scientific and Technical Information of China (English)

    赵美娜(综述); 陈公琰(审校)

    2016-01-01

    Focal adhesion kinase( FAK) ,a cytoplasmic non-receptor protein tyrosine kinase,serves as both a molecular scaffold and a mediator participating in multiple signal transduction pathways.FAK is involved in tumor cell survival,proliferation,migration and metastasis.Recent studies have shown that FAK is expressed in many tumor cells.Currently,FAK has been regarded as a potential target for cancer therapy.This review is to summarize the relationship between FAK and tumor progression.%黏着斑激酶( Focal adhesion kinase,FAK)是细胞内重要的骨架蛋白,属于一种非受体型酪氨酸蛋白激酶,也是多种信号通路的关键性分子。在肿瘤发生、发展、迁移以及侵袭的各个阶段FAK都具有重要作用。近年来,人们对FAK的研究越来越多,综合国内外研究资料表明,FAK在许多肿瘤组织中表达增高,提示FAK可能与肿瘤的发生发展密切相关,可能是肿瘤治疗的潜在靶点。该综述将对FAK分子结构及功能特点,与肿瘤的关系进行系统阐述。

  3. A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei.

    Science.gov (United States)

    Hu, Huiqing; Zhou, Qing; Li, Ziyin

    2015-10-01

    The Polo-like kinase (PLK) in Trypanosoma brucei plays multiple roles in basal body segregation, flagellum attachment, and cytokinesis. However, the mechanistic role of TbPLK remains elusive, mainly because most of its substrates are not known. Here, we report a new substrate of TbPLK, SPBB1, and its essential roles in T. brucei. SPBB1 was identified through yeast two-hybrid screening with the kinase-dead TbPLK as the bait. It interacts with TbPLK in vitro and in vivo, and is phosphorylated by TbPLK in vitro. SPBB1 localizes to both the mature basal body and the probasal body throughout the cell cycle, and co-localizes with TbPLK at the basal body during early cell cycle stages. RNAi against SPBB1 in procyclic trypanosomes inhibited basal body segregation, disrupted the new flagellum attachment zone filament, detached the new flagellum, and caused defective cytokinesis. Moreover, RNAi of SPBB1 confined TbPLK at the basal body and the bilobe structure, resulting in constitutive phosphorylation of TbCentrin2 at the bilobe. Altogether, these results identified a basal body protein as a TbPLK substrate and its essential role in promoting basal body segregation and flagellum attachment zone filament assembly for flagellum adhesion and cytokinesis initiation.

  4. The mTOR kinase inhibitor Everolimus decreases S6 kinase phosphorylation but fails to reduce mutant huntingtin levels in brain and is not neuroprotective in the R6/2 mouse model of Huntington's disease

    Directory of Open Access Journals (Sweden)

    Frentzel Stefan

    2010-06-01

    Full Text Available Abstract Background Huntington's disease (HD is a progressive neurodegenerative disorder caused by a CAG repeat expansion within the huntingtin gene. Mutant huntingtin protein misfolds and accumulates within neurons where it mediates its toxic effects. Promoting mutant huntingtin clearance by activating macroautophagy is one approach for treating Huntington's disease (HD. In this study, we evaluated the mTOR kinase inhibitor and macroautophagy promoting drug everolimus in the R6/2 mouse model of HD. Results Everolimus decreased phosphorylation of the mTOR target protein S6 kinase indicating brain penetration. However, everolimus did not activate brain macroautophagy as measured by LC3B Western blot analysis. Everolimus protected against early declines in motor performance; however, we found no evidence for neuroprotection as determined by brain pathology. In muscle but not brain, everolimus significantly decreased soluble mutant huntingtin levels. Conclusions Our data suggests that beneficial behavioral effects of everolimus in R6/2 mice result primarily from effects on muscle. Even though everolimus significantly modulated its target brain S6 kinase, this did not decrease mutant huntingtin levels or provide neuroprotection.

  5. Hepatic stellate cells induce hepatocellular carcinoma cell resistance to sorafenib through the laminin-332/α3 integrin axis recovery of focal adhesion kinase ubiquitination.

    Science.gov (United States)

    Azzariti, Amalia; Mancarella, Serena; Porcelli, Letizia; Quatrale, Anna Elisa; Caligiuri, Alessandra; Lupo, Luigi; Dituri, Francesco; Giannelli, Gianluigi

    2016-12-01

    In patients with hepatocellular carcinoma (HCC) receiving sorafenib, drug resistance is common. HCC develops in a microenvironment enriched with extracellular matrix proteins including laminin (Ln)-332, produced by hepatic stellate cells (HSCs). Ln-332 is the ligand of α3β1 and α6β4 integrins, differently expressed on the HCC cell surface, that deliver intracellular pathways. The aim of this study was to investigate the effect of Ln-332 on sorafenib's effectiveness. HCC cells were challenged with sorafenib in the presence of Ln-332 and of HSC conditioned medium (CM). Sorafenib impaired HCC cell proliferation and induced apoptosis. HSC-CM or Ln-332 inhibited sorafenib's effectiveness in HCC cells expressing both α3β1 and α6β4. Inhibiting α3 but not α6 integrin subunit using blocking antibodies or small interfering RNA abrogated the protection induced by Ln-332 and HSC-CM. Hep3B cells expressing α6β4 but lacking the α3 integrin were insensitive to Ln-332 and HSC-CM protective effects. Hep3B α3-positive, but not wild-type and scramble transfected, cells acquired protection by sorafenib when plated on Ln-332-CM or HSCs. Sorafenib dephosphorylated focal adhesion kinase (FAK) and extracellular signal-regulated kinases 1/2, whereas Ln-332 and HSC-CM partially restored the pathways. Silencing FAK, but not extracellular signal-regulated kinases 1/2, abrogated the protection induced by Ln-332 and HSC-CM, suggesting a specific role for FAK. Sorafenib down-regulated total FAK, inducing its proteasomal degradation, while Ln-332 and HSC-CM promoted the escape of FAK from ubiquitination, probably inducing a preferential membrane localization.

  6. The β5/focal adhesion kinase/glycogen synthase kinase 3β integrin pathway in high-grade osteosarcoma: a protein expression profile predictive of response to neoadjuvant chemotherapy.

    Science.gov (United States)

    Le Guellec, Sophie; Moyal, Elizabeth Cohen-Jonathan; Filleron, Thomas; Delisle, Marie-Bernadette; Chevreau, Christine; Rubie, Hervé; Castex, Marie-Pierre; de Gauzy, Jerome Sales; Bonnevialle, Paul; Gomez-Brouchet, Anne

    2013-10-01

    To date, chemosensitivity to neoadjuvant chemotherapy of patients with high-grade osteosarcoma is evaluated on surgical resection by evaluation of the percentage of necrotic cells. As yet, no predictive profile of response to chemotherapy has been used in clinical practice. Because we have previously shown that the integrin pathway controls genotoxic-induced cell death and hypoxia, we hypothesized that in primary biopsies, expression of proteins involved in this pathway could be associated with sensitivity to neoadjuvant chemotherapy in high-grade osteosarcoma. We studied β1, β3, and β5 integrin expression and integrin-linked kinase, focal adhesion kinase (FAK), glycogen synthase kinase 3β (GSK3β), Rho B, angiopoietin-2, β-catenin, and ezrin expression by immunohistochemistry in 36 biopsies of osteosarcomas obtained before treatment. All patients received a chemotherapy regimen in the neoadjuvant setting. An immunoreactive score was assessed, combining the percentage of positive tumor cells and staining intensity. We evaluated the correlation of the biomarkers with response to chemotherapy, metastasis-free survival, and overall survival. A combination of 3 biomarkers (β5 integrin, FAK, and GSK3β) discriminated good and poor responders to chemotherapy, with the highest area under the curve (89.9%; 95% confidence interval, 77.4-1.00) and a diagnostic accuracy of 90.3%. Moreover, high expression of ezrin was associated with an increased risk of metastasis (hazard ratio, 3.93; 95% confidence interval, 1.19-12.9; P = .024). We report a protein expression profile in high-grade osteosarcoma associating β5 integrin, FAK, and GSK3β that significantly correlates with poor response to neoadjuvant chemotherapy. This biomarker profile could help select patients for whom an alternative protocol using inhibitors of this pathway can be proposed.

  7. Decreased expression of intercellular adhesion molecule-1 (ICAM-1) and urokinase-type plasminogen activator receptor (uPAR) is associated with tumor cell spreading in vivo.

    Science.gov (United States)

    Donadio, Ana C; Remedi, María M; Frede, Silvia; Bonacci, Gustavo R; Chiabrando, Gustavo A; Pistoresi-Palencia, María C

    2002-01-01

    The development of an effective antitumor immune response to control tumor growth is influenced by the tumor cell itself and/or by the tumor microenvironment. Tumor invasion and tumor cell spreading require a finely tuned regulation of the formation and loosening of adhesive contacts of tumor cells with the extracellular matrix (ECM). In our laboratory, a rat tumor cell line derived from a spontaneous rat sarcoma revealed, by flow cytometry, a high frequency of intercellular adhesion molecule-1 (ICAM-1, 70.1 +/- 8.7%) and urokinase-type plaminogen activator receptor (uPAR, 51.2 +/- 5.2%) positive cells, while a weak expression of MHC class II (IA, 2.2 +/- 0.2% and IE, 17.4 +/- 3.7%) and B7 (12.1 +/- 2.2%) antigens was detected. In our tumor experimental model, after implantation of tumor cells, visible tumor masses were present at days 5-7 with a relatively fast tumor growth until day 15 (progressive phase) followed by a suppression of the tumor growth (regressive phase). Here we present data that correlates a significant decrease in the frequency of ICAM-1 and uPAR expressing tumor cells with the appearance of tumor cells in sites distant from that of the primary tumor. In addition we describe the development of a cellular immune response which controls the tumor progression and is associated with an increase in the expression of major histocompatibility complex (MHC) class II IA antigen during tumor development. The histological examination at tumor progressive and regressive time points revealed the relevant presence of polymorphonuclear neutrophils (PMNs) evidencing colliquative necrosis in tumor growth areas. Taken together, these results support the idea that the balance between adhesive interactions, proteolytic activity and tumorigenicity may lead to a tumor invasive phenotype.

  8. Inhibition of host extracellular signal-regulated kinase (ERK) activation decreases new world alphavirus multiplication in infected cells

    Energy Technology Data Exchange (ETDEWEB)

    Voss, Kelsey; Amaya, Moushimi [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Mueller, Claudius [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Roberts, Brian [Leidos Health Life Sciences, 5202 Presidents Court, Suite 110, Frederick, MD (United States); Kehn-Hall, Kylene; Bailey, Charles [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States); Petricoin, Emanuel [Center for Applied Proteomics and Personalized Medicine, George Mason University, 10900 University Boulevard, Manassas, VA (United States); Narayanan, Aarthi, E-mail: anaraya1@gmu.edu [National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, 10650 Pyramid Place, Manassas, VA (United States)

    2014-11-15

    New World alphaviruses belonging to the family Togaviridae are classified as emerging infectious agents and Category B select agents. Our study is focused on the role of the host extracellular signal-regulated kinase (ERK) in the infectious process of New World alphaviruses. Infection of human cells by Venezuelan equine encephalitis virus (VEEV) results in the activation of the ERK-signaling cascade. Inhibition of ERK1/2 by the small molecule inhibitor Ag-126 results in inhibition of viral multiplication. Ag-126-mediated inhibition of VEEV was due to potential effects on early and late stages of the infectious process. While expression of viral proteins was down-regulated in Ag-126 treated cells, we did not observe any influence of Ag-126 on the nuclear distribution of capsid. Finally, Ag-126 exerted a broad-spectrum inhibitory effect on New World alphavirus multiplication, thus indicating that the host kinase, ERK, is a broad-spectrum candidate for development of novel therapeutics against New World alphaviruses. - Highlights: • VEEV infection activated multiple components of the ERK signaling cascade. • Inhibition of ERK activation using Ag-126 inhibited VEEV multiplication. • Activation of ERK by Ceramide C6 increased infectious titers of TC-83. • Ag-126 inhibited virulent strains of all New World alphaviruses. • Ag-126 treatment increased percent survival of infected cells.

  9. Role of focal adhesion tyrosine kinases in GPVI-dependent platelet activation and reactive oxygen species formation.

    Directory of Open Access Journals (Sweden)

    Naadiya Carrim

    Full Text Available We have previously shown the presence of a TRAF4/p47phox/Hic5/Pyk2 complex associated with the platelet collagen receptor, GPVI, consistent with a potential role of this complex in GPVI-dependent ROS formation. In other cell systems, NOX-dependent ROS formation is facilitated by Pyk2, which along with its closely related homologue FAK are known to be activated and phosphorylated downstream of ligand binding to GPVI.To evaluate the relative roles of Pyk2 and FAK in GPVI-dependent ROS formation and to determine their location within the GPVI signaling pathway.Human and mouse washed platelets (from WT or Pyk2 KO mice were pre-treated with pharmacological inhibitors targeting FAK or Pyk2 (PF-228 and Tyrphostin A9, respectively and stimulated with the GPVI-specific agonist, CRP. FAK, but not Pyk2, was found to be essential for GPVI-dependent ROS production and aggregation. Subsequent human platelet studies with PF-228 confirmed FAK is essential for GPVI-mediated phosphatidylserine exposure, α-granule secretion (P-selectin (CD62P surface expression and integrin αIIbβ3 activation. To determine the precise location of FAK within the GPVI pathway, we analyzed the effect of PF-228 inhibition in CRP-stimulated platelets in conjunction with immunoprecipitation and pulldown analysis to show that FAK is downstream of Lyn, Spleen tyrosine kinase (Syk, PI3-K and Bruton's tyrosine kinase (Btk and upstream of Rac1, PLCγ2, Ca2+ release, PKC, Hic-5, NOX1 and αIIbβ3 activation.Overall, these data suggest a novel role for FAK in GPVI-dependent ROS formation and platelet activation and elucidate a proximal signaling role for FAK within the GPVI pathway.

  10. Correlation between {sup 99m}Tc-(V)-DMSA uptake and constitutive level of phosphorylated focal adhesion kinase in an in vitro model of cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Denoyer, Delphine; Perek, Nathalie; Jeune, Nathalie Le; Dubois, Francis [University of Saint-Etienne, Department of Biophysics and Radiopharmaceuticals, ' ' Cell Survival and Adhesion' ' Research Group, Jacques Lisfranc Faculty of Medicine, Saint-Etienne (France); Cornillon, Jerome [University of Saint-Etienne, Department of Haematology, ' ' Cell Survival and Adhesion' ' Research Group, Jacques Lisfranc Faculty of Medicine, Saint-Etienne (France)

    2005-07-01

    Although a number of prognostic indicators have been developed, it is still difficult to predict the biological behaviour of all cancer types. {sup 99m}Tc-(V)-DMSA (V DMSA) uptake and focal adhesion kinase (FAK) expression and activation level could be potential agents for this purpose. We hypothesised the existence of a correlation between V DMSA, whose uptake is linked to phosphate ions, essential compounds for tumour growth and cell proliferation, and the adhesion protein FAK, whose elevated expression and level of constitutive activation are implicated in cancer progression. The aim of this study was to assess the relationship between V DMSA incorporation rate and FAK expression and activation by phosphorylation on tyrosine 397 residue. We determined V DMSA uptake in six different cancer cell lines and we measured FAK expression and activation by using Western Blotting analysis. Correlations with factors known to be associated with poor prognosis, such as invasive potential, resistance to chemotherapy and proliferation rate, were also investigated. The cell lines exhibited different V DMSA incorporation rates. In addition, these cells showed the same FAK expression, but various degrees of activation. A correlation was observed between V DMSA uptake and level of FAK phosphorylation and between V DMSA or constitutive FAK activation and proliferation rate. However, no correlation was shown between these parameters and the other factors tested, i.e. invasive potential and anticancer drug resistance. The results of this in vitro study clearly demonstrate that phosphorylation of FAK, proliferation rate and V DMSA uptake are closely related. Because proliferation and a high level of constitutive FAK activation are linked to cancer progression, it can be assumed that in vivo V DMSA uptake reflects tumour aggressiveness. (orig.)

  11. Vascular growth responses to chronic arterial occlusion are unaffected by myeloid specific focal adhesion kinase (FAK) deletion

    Science.gov (United States)

    Heuslein, Joshua L.; Murrell, Kelsey P.; Leiphart, Ryan J.; Llewellyn, Ryan A.; Meisner, Joshua K.; Price, Richard J.

    2016-05-01

    Arteriogenesis, or the lumenal expansion of pre-existing arterioles in the presence of an upstream occlusion, is a fundamental vascular growth response. Though alterations in shear stress stimulate arteriogenesis, the migration of monocytes into the perivascular space surrounding collateral arteries and their differentiation into macrophages is critical for this vascular growth response to occur. Focal adhesion kinase’s (FAK) role in regulating cell migration has recently been expanded to primary macrophages. We therefore investigated the effect of the myeloid-specific conditional deletion of FAK on vascular remodeling in the mouse femoral arterial ligation (FAL) model. Using laser Doppler perfusion imaging, whole mount imaging of vascular casted gracilis muscles, and immunostaining for CD31 in gastrocnemius muscles cross-sections, we found that there were no statistical differences in perfusion recovery, arteriogenesis, or angiogenesis 28 days after FAL. We therefore sought to determine FAK expression in different myeloid cell populations. We found that FAK is expressed at equally low levels in Ly6Chi and Ly6Clo blood monocytes, however expression is increased over 2-fold in bone marrow derived macrophages. Ultimately, these results suggest that FAK is not required for monocyte migration to the perivascular space and that vascular remodeling following arterial occlusion occurs independently of myeloid specific FAK.

  12. Expression of focal adhesion kinase and α5 and β1 integrins in carcinomas and its clinical significance

    Institute of Scientific and Technical Information of China (English)

    Jian-Min Su; Lu Gui; Yi-Ping Zhou; Xi-Liang Zha

    2002-01-01

    AIM: To detect the expression pattern of FAK (focaladhesion kinase) and integrin α5 and β1 subunits indifferent kinds of cancerous tissues and to study theircorrelation with clinicopathological data includingtumor type, grade and lymph node status. METHODS:Using an immunohistochemical technique, weexamined the expression of FAK and integrin andsubunits in cancerous and noncancerous tissuesobtained from 75 patients with gastric carcinomas, 21colorectal carcinomas, 16 hepatocellular carcinomas,20 uterocervical carcinomas, and 20 breast carcinomas.RESULTS: The staining of FAK was stronger in cancerousthan in noncancerous areas. Enhanced expression ofFAKwas detected in poor-differentiated carcinoma ofthe stomach and colorectum. Tumors with lymph nodemetastases had more FAK protein than those withoutmetastases. In addition, the deeper the extent of tumorinfiltration, the higher the FAK expression. Theexpression of integrin α5 and β1 subunits was lower incancerous areas than in noncancerous areas, but it washigher in well-differentiated cancerous tissues than inpoor differentiated tissues. The relationship betweenthe expression of integrin α5 and β1 subunits andinfiltration or metastasis was not significant. Cancerous tissues with stronger FAK expression (++ or +++) alsohad a higher expression of integrin α5 and β1 subunitsin the tumor and its unaffected margins.CONCLUSION: FAK is a better marker for carcinogenesisand the progression of cancer than integrin α5 or β1subunit, and it may be not only a transformation-linkedenzyme but also a progression-linked enzyme.

  13. A small physiological electric field mediated responses of extravillous trophoblasts derived from HTR8/SVneo cells: involvement of activation of focal adhesion kinase signaling.

    Directory of Open Access Journals (Sweden)

    Juan Zhang

    Full Text Available Moderate invasion of trophoblast cells into endometrium is essential for the placental development and normal pregnancy. Electric field (EF-induced effects on cellular behaviors have been observed in many cell types. This study was to investigate the effect of physiological direct current EF (dc EF on cellular responses such as elongation, orientation and motility of trophoblast cells. Immortalized first trimester extravillous trophoblast cells (HTR-8/SVneo were exposed to the dc EF at physiological magnitude. Cell images were recorded and analyzed by image analyzer. Cell lysates were used to detect protein expression by Western blot. Cultured in the dc EFs the cells showed elongation, orientation and enhanced migration rate compared with non-EF stimulated cells at field strengths of 100 mV/mm to 200 mV/mm. EF exposure increased focal adhesion kinase (FAK phosphorylation in a time-dependent manner and increased expression levels of MMP-2. Pharmacological inhibition of FAK impaired the EF-induced responses including motility and abrogated the elevation of MMP-2 expression. However, the expression levels of integrins like integrin α1, α5, αV and β1 were not affected by EF stimulation. Our results demonstrate the importance of FAK activation in migration/motility of trophobalst cells driven by EFs. In addition, it raises the feasibility of using applied EFs to promote placentation through effects on trophoblast cells.

  14. MicroRNA-151 and its hosting gene FAK (focal adhesion kinase) regulate tumor cell migration and spreading of hepatocellular carcinoma.

    Science.gov (United States)

    Luedde, Tom

    2010-09-01

    Recurrent chromosomal aberrations are often observed in hepatocellular carcinoma (HCC), but little is known about the functional non-coding sequences, particularly microRNAs (miRNAs), at the chromosomal breakpoints in HCC. Here we show that 22 miRNAs are often amplified or deleted in HCC. MicroRNA-151 (miR-151), a frequently amplified miRNA on 8q24.3, is correlated with intrahepatic metastasis of HCC. We further show that miR-151, which is often expressed together with its host gene FAK, encoding focal adhesion kinase, significantly increases HCC cell migration and invasion in vitro and in vivo, mainly through miR-151-5p, but not through miR-151-3p. Moreover, miR-151 exerts this function by directly targeting RhoGDIA, a putative metastasis suppressor in HCC, thus leading to the activation of Rac1, Cdc42 and Rho GTPases. In addition, miR-151 can function synergistically with FAK to enhance HCC cell motility and spreading. Thus, our findings indicate that chromosome gain of miR-151 is a crucial stimulus for tumour invasion and metastasis of HCC.

  15. Polycystin-1 Induces Cell Migration by Regulating Phosphatidylinositol 3-kinase-dependent Cytoskeletal Rearrangements and GSK3β-dependent Cell–Cell Mechanical Adhesion

    Science.gov (United States)

    Boca, Manila; D'Amato, Lisa; Distefano, Gianfranco; Polishchuk, Roman S.; Germino, Gregory G.

    2007-01-01

    Polycystin-1 (PC-1) is a large plasma-membrane receptor encoded by the PKD1 gene mutated in autosomal dominant polycystic kidney disease (ADPKD). Although the disease is thought to be recessive on a molecular level, the precise mechanism of cystogenesis is unclear, although cytoarchitecture defects seem to be the most likely initiating events. Here we show that PC-1 regulates the actin cytoskeleton in renal epithelial cells (MDCK) and induces cell scattering and cell migration. All of these effects require phosphatidylinositol 3-kinase (PI3-K) activity. Consistent with these observations Pkd1−/− mouse embryonic fibroblasts (MEFs) have reduced capabilities to migrate compared with controls. PC-1 overexpressing MDCK cells are able to polarize normally with proper adherens and tight junctions formation, but show quick reabsorption of ZO-1, E-cadherin, and β-catenin upon wounding of a monolayer and a transient epithelial-to-mesenchymal transition (EMT) that favors a rapid closure of the wound and repolarization. Finally, we show that PC-1 is able to control the turnover of cytoskeletal-associated β-catenin through activation of GSK3β. Expression of a nondegradable form of β-catenin in PC-1 MDCK cells restores strong cell–cell mechanical adhesion. We propose that PC-1 might be a central regulator of epithelial plasticity and its loss results in impaired normal epithelial homeostasis. PMID:17671167

  16. L1 cell adhesion molecule induces melanoma cell motility by activation of mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yi, Young-Su; Baek, Kwang-Soo; Cho, Jae Youl

    2014-06-01

    L1 cell adhesion molecule (L1CAM) is highly expressed in various types of cancer cells and has been implicated in the control of cell proliferation and motility. Recently, L1CAM was reported to induce the motility of melanoma cells, but the mechanism of this induction remains poorly understood. In this study, we investigated the molecular mechanisms by which L1CAM induces the motility of melanoma cells. Unlike other types of cancer cells, B16F10 melanoma cells highly expressed L1CAM at both the RNA and protein levels, and the expression of L1CAM induced AP-1 activity. In accordance to AP-1 activation, MAPK signaling pathways were activated by L1CAM. Inhibition of L1CAM expression by L1CAM-specific siRNA suppressed the activation of MAPKs such as ERK and p38. However, no significant change was observed in JNK activation. As expected, upstream MAP2K, MKK3/6, MAP3K, and TAK1 were also deactivated by the inhibition of L1CAM expression. L1CAM induced the motility of B16F10 cells. Inhibition of L1CAM expression suppressed migration and invasion of B16F10 cells, but no suppressive effect was observed on their proliferation and anti-apoptotic resistance. Treatment of B16F10 cells with U0126, an ERK inhibitor, or SB203580, a p38 inhibitor, suppressed the migration and invasion abilities of B16F10 cells. Taken together, our results suggest that L1CAM induces the motility of B16F10 melanoma cells via the activation of MAPK pathways. This finding provides a more detailed molecular mechanism of L1CAM-mediated induction of melanoma cell motility.

  17. Dynamic monitoring of changes in endothelial cell-substrate adhesiveness during leukocyte adhesion by microelectrical impedance assay

    Institute of Scientific and Technical Information of China (English)

    Yakun Ge; Tongle Deng; Xiaoxiang Zheng

    2009-01-01

    Adhesion of leukocytes to endothelial cells in inflammation processes leads to changes of endothelial cell-substrate adhesiveness, and understanding of such changes will provide us with important information of inflammation processes. In this study, we used a non-invasive biosensor system referred to as real-time cell electronic sensor (RT-CES) system to monitor the changes in endothelial cell-substrate adhesiveness induced by human monoblastic cell line U937 cell adhesion in a dynamic and quantitative manner. This assay, which is based on cell-substrate impedance readout, is able to monitor transient changes in cell-substrate adhesiveness as a result of U937 cell adhesion. The U937 cell adhesion to endothelial cells was induced by lipopolysaccharide (LPS) in a dose-dependent manner. Although the number of adherent U937 cells to the endothelial cells was verified by a standard assay, the adhesiveness of endothelial cells after addition of U937 cells was monitored by the RT-CES system. Furthermore, focal adhesion kinase protein decrease and F-actin rearrangement in endothelial cells were observed after addition of U937 cells. Our results indicated that the adhesion of U937 cells to LPS-treated endothelial cells reduced the cell adhesiveness to the substrate, and such reduction might facilitate infiltration of leukocytes.

  18. Manganese-induced integrin affinity maturation promotes recruitment of alpha V beta 3 integrin to focal adhesions in endothelial cells: evidence for a role of phosphatidylinositol 3-kinase and Src.

    Science.gov (United States)

    Dormond, Olivier; Ponsonnet, Lionel; Hasmim, Meriem; Foletti, Alessandro; Rüegg, Curzio

    2004-07-01

    Integrin activity is controlled by changes in affinity (i.e. ligand binding) and avidity (i.e. receptor clustering). Little is known, however, about the effect of affinity maturation on integrin avidity and on the associated signaling pathways. To study the effect of affinity maturation on integrin avidity, we stimulated human umbilical vein endothelial cells (HUVEC) with MnCl(2) to increase integrin affinity and monitored clustering of beta 1 and beta 3 integrins. In unstimulated HUVEC, beta 1 integrins were present in fibrillar adhesions, while alpha V beta 3 was detected in peripheral focal adhesions. Clustered beta 1 and beta 3 integrins expressed high affinity/ligand-induced binding site (LIBS) epitopes. MnCl(2)-stimulation promoted focal adhesion and actin stress fiber formation at the basal surface of the cells, and strongly enhanced mAb LM609 staining and expression of beta 3 high affinity/LIBS epitopes at focal adhesions. MnCl(2)-induced alpha V beta 3 clustering was blocked by a soluble RGD peptide, by wortmannin and LY294002, two pharmacological inhibitors of phosphatidylinositol 3-kinase (PI 3-K), and by over-expressing a dominant negative PI 3-K mutant protein. Conversely, over-expression of active PI 3-K and pharmacological inhibiton of Src with PP2 and CGP77675, enhanced basal and manganese-induced alpha V beta 3 clustering. Transient increased phosphorylation of protein kinase B/Akt, a direct target of PI 3K, occurred upon manganese stimulation. MnCl(2) did not alter beta 1 integrin distribution or beta1 high-affinity/LIBS epitope expression. Based on these results, we conclude that MnCl(2)-induced alpha V beta 3 integrin affinity maturation stimulates focal adhesion and actin stress fiber formation, and promotes recruitment of high affinity alpha V beta 3 to focal adhesions. Affinity-modulated alpha V beta 3 clustering requires PI3-K signaling and is negatively regulate by Src.

  19. Indium gallium zinc oxide layer used to decrease optical reflection loss at intermediate adhesive region for fabricating mechanical stacked multijunction solar cells

    Science.gov (United States)

    Sameshima, Toshiyuki; Nimura, Takeshi; Sugawara, Takashi; Ogawa, Yoshihiro; Yoshidomi, Shinya; Kimura, Shunsuke; Hasumi, Masahiko

    2017-01-01

    Reduction of optical reflection loss is discussed in three mechanical stacked samples: top crystalline silicon and bottom crystalline germanium substrates, top crystalline GaAs and bottom crystalline silicon substrates, and top crystalline GaP and bottom crystalline silicon substrates using an epoxy-type adhesive with a reflective index of 1.47. Transparent conductive Indium gallium zinc oxide (IGZO) layers with a refractive index of 1.85 were used as antireflection layers. IGZO layers were formed on the bottom surface of the top substrate and the top surface of the bottom substrate of the three stacked samples with thicknesses of 188, 130, and 102 nm. The insertion of IGZO layers decreased the optical reflectivity of the stacked samples. The IGZO layers provided high effective optical absorbency of bottom substrates of 0.925, 0.943, and 0.931, respectively, for light wavelength regions for light in which the top substrates were transparent and the bottom substrates were opaque.

  20. Stable expression of sialyl-Tn antigen in T47-D cells induces a decrease of cell adhesion and an increase of cell migration.

    Science.gov (United States)

    Julien, Sylvain; Lagadec, Chann; Krzewinski-Recchi, Marie-Ange; Courtand, Gilles; Le Bourhis, Xuefen; Delannoy, Philippe

    2005-03-01

    Sialyl-Tn is a carbohydrate antigen overexpressed in several epithelial cancers including breast cancer, and usually associated with poor prognosis. Sialyl-Tn is synthesized by a CMP-Neu5Ac: GalNAc alpha2,6-sialyltransferase: ST6GalNAc I, which catalyzes the transfer of a sialic acid residue in alpha2,6-linkage to the GalNAcalpha1-O-Ser/Thr structure. The resulting disaccharide (Neu5Acalpha2-6GalNAcalpha1-O-Ser/Thr) cannot be further elongated and sialyl-Tn expression results therefore in a shortening of the O-glycan chains. However, usual breast cancer cell lines express neither ST6GalNAc I nor sialyl-Tn antigen. We have previously shown that stable transfection of MDA-MB-231 cells with the hST6GalNAc I cDNA induces the sialyl-Tn antigen expression at the cell surface and leads to a decreased cell growth and an increased cell migration. We describe herein the generation of new T47-D clones expressing sialyl-Tn antigen after hST6GalNAc I cDNA stable transfection. sialyl-Tn antigen is carried by several high molecular weight membrane bound O-glycoproteins, including MUC1. We show that sialyl-Tn expression induces a decrease of cell growth and adhesion, and an increase of cell migration in sialyl-Tn positive clones compared to mock transfected cells. These observations show that the alteration of the O-glycans pattern is sufficient to modify the biological features of cancer cells. These T47-D sialyl-Tn expressing clones might allow further in vivo investigation to determine precisely the impact of such O-glycosylation modifications on breast cancer development.

  1. Focal Adhesion Kinase Inhibitors in Combination with Erlotinib Demonstrate Enhanced Anti-Tumor Activity in Non-Small Cell Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Grant A Howe

    Full Text Available Blockade of epidermal growth factor receptor (EGFR activity has been a primary therapeutic target for non-small cell lung cancers (NSCLC. As patients with wild-type EGFR have demonstrated only modest benefit from EGFR tyrosine kinase inhibitors (TKIs, there is a need for additional therapeutic approaches in patients with wild-type EGFR. As a key component of downstream integrin signalling and known receptor cross-talk with EGFR, we hypothesized that targeting focal adhesion kinase (FAK activity, which has also been shown to correlate with aggressive stage in NSCLC, would lead to enhanced activity of EGFR TKIs. As such, EGFR TKI-resistant NSCLC cells (A549, H1299, H1975 were treated with the EGFR TKI erlotinib and FAK inhibitors (PF-573,228 or PF-562,271 both as single agents and in combination. We determined cell viability, apoptosis and 3-dimensional growth in vitro and assessed tumor growth in vivo. Treatment of EGFR TKI-resistant NSCLC cells with FAK inhibitor alone effectively inhibited cell viability in all cell lines tested; however, its use in combination with the EGFR TKI erlotinib was more effective at reducing cell viability than either treatment alone when tested in both 2- and 3-dimensional assays in vitro, with enhanced benefit seen in A549 cells. This increased efficacy may be due in part to the observed inhibition of Akt phosphorylation when the drugs were used in combination, where again A549 cells demonstrated the most inhibition following treatment with the drug combination. Combining erlotinib with FAK inhibitor was also potent in vivo as evidenced by reduced tumor growth in the A549 mouse xenograft model. We further ascertained that the enhanced sensitivity was irrespective of the LKB1 mutational status. In summary, we demonstrate the effectiveness of combining erlotinib and FAK inhibitors for use in known EGFR wild-type, EGFR TKI resistant cells, with the potential that a subset of cell types, which includes A549, could be

  2. Stabilization of the cyclin-dependent kinase 5 activator, p35, by paclitaxel decreases beta-amyloid toxicity in cortical neurons.

    Science.gov (United States)

    Li, Guibin; Faibushevich, Alexander; Turunen, Brandon J; Yoon, Sung Ok; Georg, Gunda; Michaelis, Mary L; Dobrowsky, Rick T

    2003-01-01

    One hallmark of Alzheimer's disease (AD) is the formation of neurofibrillary tangles, aggregated paired helical filaments composed of hyperphosphorylated tau. Amyloid-beta (Abeta) induces tau hyperphosphorylation, decreases microtubule (MT) stability and induces neuronal death. MT stabilizing agents have been proposed as potential therapeutics that may minimize Abeta toxicity and here we report that paclitaxel (taxol) prevents cell death induced by Abeta peptides, inhibits Abeta-induced activation of cyclin-dependent kinase 5 (cdk5) and decreases tau hyperphosphorylation. Taxol did not inhibit cdk5 directly but significantly blocked Abeta-induced calpain activation and decreased formation of the cdk5 activator, p25, from p35. Taxol specifically inhibited the Abeta-induced activation of the cytosolic cdk5-p25 complex, but not the membrane-associated cdk5-p35 complex. MT-stabilization was necessary for neuroprotection and inhibition of cdk5 but was not sufficient to prevent cell death induced by overexpression of p25. As taxol is not permeable to the blood-brain barrier, we assessed the potential of taxanes to attenuate Abeta toxicity in adult animals using a succinylated taxol analog (TX67) permeable to the blood-brain barrier. TX67, but not taxol, attenuated the magnitude of both basal and Abeta-induced cdk5 activation in acutely dissociated cortical cultures prepared from drug treated adult mice. These results suggest that MT-stabilizing agents may provide a therapeutic approach to decrease Abeta toxicity and neurofibrillary pathology in AD and other tauopathies.

  3. Reactive oxygen species decrease cAMP response element binding protein expression in cardiomyocytes via a protein kinase D1-dependent mechanism that does not require Ser133 phosphorylation.

    Science.gov (United States)

    Ozgen, Nazira; Guo, Jianfen; Gertsberg, Zoya; Danilo, Peter; Rosen, Michael R; Steinberg, Susan F

    2009-10-01

    Reactive oxygen species (ROS) exert pleiotropic effects on a wide array of signaling proteins that regulate cellular growth and apoptosis. This study shows that long-term treatment with a low concentration of H2O2 leads to the activation of signaling pathways involving extracellular signal-regulated kinase, ribosomal protein S6 kinase, and protein kinase D (PKD) that increase cAMP binding response element protein (CREB) phosphorylation at Ser(133) in cardiomyocytes. Although CREB-Ser(133) phosphorylation typically mediates cAMP-dependent increases in CREB target gene expression, the H2O2-dependent increase in CREB-Ser(133) phosphorylation is accompanied by a decrease in CREB protein abundance and no change in Cre-luciferase reporter activity. Mutagenesis studies indicate that H2O2 decreases CREB protein abundance via a mechanism that does not require CREB-Ser(133) phosphorylation. Rather, the H2O2-dependent decrease in CREB protein is prevented by the proteasome inhibitor lactacystin, by inhibitors of mitogen-activated protein kinase kinase or protein kinase C activity, or by adenoviral-mediated delivery of a small interfering RNA that decreases PKD1 expression. A PKD1-dependent mechanism that links oxidative stress to decreased CREB protein abundance is predicted to contribute to the pathogenesis of heart failure by influencing cardiac growth and apoptosis responses.

  4. Targeted inhibition of Focal Adhesion Kinase Attenuates Cardiac Fibrosis and Preserves Heart Function in Adverse Cardiac Remodeling

    Science.gov (United States)

    Zhang, Jie; Fan, Guangpu; Zhao, Hui; Wang, Zhiwei; Li, Fei; Zhang, Peide; Zhang, Jing; Wang, Xu; Wang, Wei

    2017-01-01

    Cardiac fibrosis in post-myocardial infarction (MI), seen in both infarcted and non-infarcted myocardium, is beneficial to the recovery of heart function. But progressively pathological fibrosis impairs ventricular function and leads to poor prognosis. FAK has recently received attention as a potential mediator of fibrosis, our previous study reported that pharmacological inhibition of FAK can attenuate cardiac fibrosis in post MI models. However, the long-term effects on cardiac function and adverse cardiac remodelling were not clearly investigated. In this study, we tried to determine the preliminary mechanisms in regulating CF transformation to myofibroblasts and ECM synthesis relevant to the development of adverse cardiac remolding in vivo and in vitro. Our study provides even more evidence that FAK is directly related to the activation of CF in hypoxia condition in a dose-dependent and time-dependent manner. Pharmacological inhibition of FAK significantly reduces myofibroblast differentiation; our in vivo data demonstrated that a FAK inhibitor significantly decreases fibrotic score, and preserves partial left ventricular function. Both PI3K/AKT signalling and ERK1/2 are necessary for hypoxia-induced CF differentiation and ECM synthesis; this process also involves lysyl oxidase (LOX). These findings suggest that pharmacological inhibition of FAK may become an effective therapeutic strategy against adverse fibrosis. PMID:28225063

  5. Myocardial Ablation of G Protein-Coupled Receptor Kinase 2 (GRK2 Decreases Ischemia/Reperfusion Injury through an Anti-Intrinsic Apoptotic Pathway.

    Directory of Open Access Journals (Sweden)

    Qian Fan

    Full Text Available Studies from our lab have shown that decreasing myocardial G protein-coupled receptor kinase 2 (GRK2 activity and expression can prevent heart failure progression after myocardial infarction. Since GRK2 appears to also act as a pro-death kinase in myocytes, we investigated the effect of cardiomyocyte-specific GRK2 ablation on the acute response to cardiac ischemia/reperfusion (I/R injury. To do this we utilized two independent lines of GRK2 knockout (KO mice where the GRK2 gene was deleted in only cardiomyocytes either constitutively at birth or in an inducible manner that occurred in adult mice prior to I/R. These GRK2 KO mice and appropriate control mice were subjected to a sham procedure or 30 min of myocardial ischemia via coronary artery ligation followed by 24 hrs reperfusion. Echocardiography and hemodynamic measurements showed significantly improved post-I/R cardiac function in both GRK2 KO lines, which correlated with smaller infarct sizes in GRK2 KO mice compared to controls. Moreover, there was significantly less TUNEL positive myocytes, less caspase-3, and -9 but not caspase-8 activities in GRK2 KO mice compared to control mice after I/R injury. Of note, we found that lowering cardiac GRK2 expression was associated with significantly lower cytosolic cytochrome C levels in both lines of GRK2 KO mice after I/R compared to corresponding control animals. Mechanistically, the anti-apoptotic effects of lowering GRK2 expression were accompanied by increased levels of Bcl-2, Bcl-xl, and increased activation of Akt after I/R injury. These findings were reproduced in vitro in cultured cardiomyocytes and GRK2 mRNA silencing. Therefore, lowering GRK2 expression in cardiomyocytes limits I/R-induced injury and improves post-ischemia recovery by decreasing myocyte apoptosis at least partially via Akt/Bcl-2 mediated mitochondrial protection and implicates mitochondrial-dependent actions, solidifying GRK2 as a pro-death kinase in the heart.

  6. A novel cardioprotective agent in cardiac transplantation: metformin activation of AMP-activated protein kinase decreases acute ischemia-reperfusion injury and chronic rejection.

    Science.gov (United States)

    Chin, Jocelyn T; Troke, Joshua J; Kimura, Naoyuki; Itoh, Satoshi; Wang, Xi; Palmer, Owen P; Robbins, Robert C; Fischbein, Michael P

    2011-12-01

    The main cause of mortality after the first year from cardiac transplantation is cardiac allograft vasculopathy (CAV), which leads to chronic rejection of the heart. To improve long-term outcomes in cardiac transplantation, treatments to prevent or diminish CAV are actively being researched. Ischemia-reperfusion (I-R) injury has been shown to be the strongest alloantigen-independent factor in the development of CAV. Here, we investigate the use of metformin in murine cardiac transplantation models as a novel cardioprotective agent to limit acute I-R injury and subsequent chronic rejection. We show that metformin treatment activates AMP-activated kinase (AMPK) in vitro and in vivo. In the acute transplantation model, metformin activation of AMPK resulted in significantly decreased apoptosis in cardiac allografts on postoperative day (POD) 1 and 8. In the chronic transplantation model, metformin pretreatment of allografts led to significantly improved graft function and significantly decreased CAV, as measured on POD 52. Taken together, our results in the acute and chronic rejection studies suggest a potential cardioprotective mechanism for metformin; we demonstrate a correlation between metformin-induced decrease in acute I-R injury and metformin-related decrease in chronic rejection. Thus, one of the ways by which metformin and AMPK activation may protect the transplanted heart from chronic rejection is by decreasing initial I-R injury inherent in donor organ preservation and implantation. Our findings suggest novel therapeutic strategies for minimizing chronic cardiac rejection via the use of metformin- and AMPK-mediated pathways to suppress acute I-R injury.

  7. 局部黏着斑激酶作为肿瘤治疗靶点的研究进展%Focal adhesion kinase, a novel target for cancer therapy

    Institute of Scientific and Technical Information of China (English)

    张文静; 黄启来; 华子春

    2011-01-01

    局部黏着斑激酶(focal adhesion kinase,FAK)是一种非受体型酪氨酸蛋白激酶,是细胞内重要的骨架蛋白与多种信号通路的关键分子.FAK在肿瘤发生、发展、迁移和侵袭的各个阶段都具有重要作用,FAK己经被当作潜在的肿瘤治疗靶点来研究.该综述将对FAK与肿瘤的关系以及FAK作为肿瘤治疗靶点的研究进展进行探讨.%Focal adhesion kinase (FAK), a cytoplasmic non-receptor protein tyrosine kinase, serves as both a molecular scaffold and a mediator participating in multiple signal transduction pathways. FAK is involved in tumor cell survival, proliferation, migration and metastasis. Currently, FAK has been regarded as a potential target for cancer therapy. This review is to summarize the relationship between FAK and tumor progression, and to discuss the strategies targeting FAK for cancer treatment.

  8. R59949, a diacylglycerol kinase inhibitor, inhibits inducible nitric oxide production through decreasing transplasmalemmal L-arginine uptake in vascular smooth muscle cells.

    Science.gov (United States)

    Shimomura, Tomoko; Nakano, Tomoyuki; Goto, Kaoru; Wakabayashi, Ichiro

    2017-02-01

    Although diacylglycerol kinase (DGK) is known to be expressed in vascular smooth muscle cell, its functional significance remains to be clarified. We hypothesized that DGK is involved in the pathway of cytokine-induced nitric oxide (NO) production in vascular smooth muscle cells. The purpose of this study was to investigate the effects of R59949, a diacylglycerol kinase inhibitor, on inducible nitric oxide production in vascular smooth muscle cell. Cultured rat aortic smooth muscle cells (RASMCs) were used to elucidate the effects of R59949 on basal and interleukin-1β (IL-1β)-induced NO production. The effects of R59949 on protein and mRNA expression of induced nitric oxide synthase (iNOS) and on transplasmalemmal L-arginine uptake were also evaluated using RASMCs. Treatment of RASMCs with R59949 (10 μM) inhibited IL-1β (10 ng/ml)-induced NO production but not basal NO production. Neither protein nor mRNA expression level of iNOS after stimulation with IL-1β was significantly affected by R59949. Estimated enzymatic activities of iNOS in RASMCs were comparable in the absence and presence of R59949. Stimulation of RASMCs with IL-1β caused a marked increase in transplasmalemmal L-arginine uptake into RASMCs. L-Arginine uptake in the presence of IL-1β was markedly inhibited by R59949, while basal L-arginine uptake was not significantly affected by R59949. Both IL-1β-induced NO production and L-arginine uptake were abolished in the presence of cycloheximide (1 μM). The results indicate that R59949 inhibits inducible NO production through decreasing transplasmalemmal L-arginine uptake. DGK is suggested to be involved in cytokine-stimulated L-arginine transport and regulate its intracellular concentration in vascular smooth muscle cell.

  9. A high isoflavone diet decreases 5' adenosine monophosphate-activated protein kinase activation and does not correct selenium-induced elevations in fasting blood glucose in mice.

    Science.gov (United States)

    Stallings, Michael T; Cardon, Brandon R; Hardman, Jeremy M; Bliss, Tyler A; Brunson, Scott E; Hart, Chris M; Swiss, Maria D; Hepworth, Squire D; Christensen, Merrill J; Hancock, Chad R

    2014-04-01

    Selenium (Se) has been implicated as a micronutrient that decreases adenosine monophosphate-activated protein kinase (AMPK) signaling and may increase diabetes risk by reducing insulin sensitivity. Soy isoflavones (IF) are estrogen-like compounds that have been shown to attenuate insulin resistance, hyperglycemia, adiposity, and increased AMPK activation. We hypothesized that a high IF (HIF) diet would prevent the poor metabolic profile associated with high Se intake. The purpose of this study was to examine changes in basal glucose metabolism and AMPK signaling in response to an HIF diet and/or supplemental Se in a mouse model. Male FVB mice were divided into groups receiving either a control diet with minimal IF (low IF) or an HIF diet. Each dietary group was further subdivided into groups receiving either water or Se at a dose of 3 mg Se/kg body weight daily, as Se-methylselenocysteine (SMSC). After 5 months, mice receiving SMSC had elevated fasting glucose (P < .05) and a tendency for glucose intolerance (P = .08). The increase in dietary IF did not result in improved fasting blood glucose. Interestingly, after 6 months, HIF-fed mice had decreased basal AMPK activation in liver and skeletal muscle tissue (P < .05). Basal glucose metabolism was changed by SMSC supplementation as evidenced by increased fasting blood glucose and glucose intolerance. High dietary IF levels did not protect against aberrant blood glucose. In FVB mice, decreased basal AMPK activation is not the mechanism through which Se exerts its effect. These results suggest that more research must be done to elucidate the role of Se and IF in glucose metabolism.

  10. Mitogen-activated protein kinases mediate Mycobacterium tuberculosis–induced CD44 surface expression in monocytes

    Indian Academy of Sciences (India)

    Natarajan Palaniappan; S Anbalagan; Sujatha Narayanan

    2012-03-01

    CD44, an adhesion molecule, has been reported to be a binding site for Mycobacterium tuberculosis (M. tuberculosis) in macrophages and it also mediates mycobacterial phagocytosis, macrophage recruitment and protective immunity against pulmonary tuberculosis in vivo. However, the signalling pathways that are involved in M. tuberculosis–induced CD44 surface expression in monocytic cells are currently unknown. Exposure of THP-1 human monocytes to M. tuberculosis H37Rv and H37Ra induced distinct, time-dependent, phosphorylation of mitogen-activated protein kinase kinase-1, extracellular signal regulated kinase 1/2, mitogen-activated protein kinase kinase 3/6, p38 mitogen-activated protein kinase and c-jun N-terminal kinases. The strains also differed in their usage of CD14 and human leukocyte antigen-DR (HLA-DR) receptors in mediating mitogen-activated protein kinase activation. M. tuberculosis H37Rv strain induced lower CD44 surface expression and tumour necrosis factor-alpha levels, whereas H37Ra the reverse. Using highly specific inhibitors of mitogen-activated protein kinase kinase-1, p38 mitogen-activated protein kinase and c-jun N-terminal kinase, we report that inhibition of extracellular signal regulated kinase 1/2 and c-jun N-terminal kinases increases, but that inhibition of p38 mitogen-activated protein kinase decreases M. tuberculosis–induced CD44 surface expression in THP-1 human monocytes.

  11. Herbivore perception decreases photosynthetic carbon-assimilation and reduces stomatal conductance by engaging 12-oxo-phytodienoic acid, mitogen-activated protein kinase 4 and cytokinin perception.

    Science.gov (United States)

    Meza-Canales, Ivan D; Meldau, Stefan; Zavala, Jorge A; Baldwin, Ian T

    2016-12-07

    Herbivory-induced changes in photosynthesis have been documented in many plant species, however the complexity of photosynthetic regulation and analysis has thwarted progress in understanding the mechanism involved, particularly those elicited by herbivore-specific elicitors. Here we analyzed the early photosynthetic gas-exchange responses in Nicotiana attenuata plants after wounding and elicitation with Manduca sexta oral-secretions, and the pathways regulating these responses. Elicitation with M. sexta oral-secretions rapidly decreased photosynthetic carbon-assimilation (AC ) in treated and systemic (untreated, vascularly connected) leaves, which were associated with changes in stomatal conductance, rather than with changes in Rubisco activity and RuBP-turnover. Phytohormone profiling and gas-exchange-analysis of oral-secretion-elicited transgenic plants altered in phytohormone regulation, biosynthesis and perception, combined with micrografting techniques, revealed that the local photosynthetic-responses were mediated by 12-oxo-phytodienoic acid (OPDA), while the systemic responses involved interactions among jasmonates, cytokinins and abscisic acid signaling mediated by mitogen activated protein kinase 4 (MPK4). The analysis also revealed a role for cytokinins interacting with MPK4 in CO2 -mediated stomatal regulation. Hence oral-secretions, while eliciting jasmonic acid-mediated defense responses, also elicits OPDA-mediated changes in stomatal conductance and AC , an observation illustrating the complexity and economy of the signaling that regulates defense and carbon assimilation pathways in response to herbivore attack.

  12. Growth arrest- and DNA-damage-inducible 45beta gene inhibits c-Jun N-terminal kinase and extracellular signal-regulated kinase and decreases IL-1beta-induced apoptosis in insulin-producing INS-1E cells

    DEFF Research Database (Denmark)

    Larsen, Claus Morten; Døssing, M G; Papa, S;

    2006-01-01

    IL-1beta is a candidate mediator of apoptotic beta cell destruction, a process that leads to type 1 diabetes and progression of type 2 diabetes. IL-1beta activates beta cell c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) and p38, all of which are members of the mitogen...

  13. (-)-Epigallocatechin-3-gallate decreases thrombin/paclitaxel-induced endothelial tissue factor expression via the inhibition of c-Jun terminal NH2 kinase phosphorylation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Huang-Joe [Institute of Biotechnology, National Tsing Hua University, No. 101, Section 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China); Division of Cardiology, Department of Medicine, China Medical University Hospital, No. 2, Yuh-Der Road, Taichung 40447, Taiwan (China); Lo, Wan-Yu [Department of Medical Research, China Medical University Hospital, No. 2, Yuh-Der Road, Taichung 40447, Taiwan (China); Graduate Integration of Chinese and Western Medicine, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan (China); Lu, Te-Ling [School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road, Taichung 40402, Taiwan (China); Huang, Haimei, E-mail: hmhuang@life.nthu.edu.tw [Institute of Biotechnology, National Tsing Hua University, No. 101, Section 2, Kuang Fu Road, Hsinchu 30013, Taiwan (China)

    2010-01-01

    Patients with paclitaxel-eluting stents are concerned with stent thrombosis caused by premature discontinuation of dual antiplatelet therapy or clopidogrel resistance. This study investigates the effect of (-)-epigallocatechin-3-gallate (EGCG) on the expression of thrombin/paclitaxel-induced endothelial tissue factor (TF) expressions in human aortic endothelial cells (HAECs). EGCG was nontoxic to HAECs at 6 h up to a concentration of 25 {mu}mol/L. At a concentration of 25 {mu}mol/L, EGCG pretreatment potently inhibited both thrombin-stimulated and thrombin/paclitaxel-stimulated endothelial TF protein expression. Thrombin and thrombin/paclitaxel-induced 2.6-fold and 2.9-fold increases in TF activity compared with the control. EGCG pretreatment caused a 29% and 38% decrease in TF activity on thrombin and thrombin/paclitaxel treatment, respectively. Real-time polymerase chain reaction (PCR) showed that thrombin and thrombin/paclitaxel-induced 3.0-fold and 4.6-fold TF mRNA expressions compared with the control. EGCG pretreatment caused an 82% and 72% decrease in TF mRNA expression on thrombin and thrombin/paclitaxel treatment, respectively. The c-Jun terminal NH2 kinase (JNK) inhibitor SP600125 reduced thrombin/paclitaxel-induced TF expression. Furthermore, EGCG significantly inhibited the phosphorylation of JNK to 49% of thrombin/paclitaxel-stimulated HAECs at 60 min. Immunofluorescence assay did not show an inhibitory effect of EGCG on P65 NF-{kappa}B nuclear translocation in the thrombin/paclitaxel-stimulated endothelial cells. In conclusion, EGCG can inhibit TF expression in thrombin/paclitaxel-stimulated endothelial cells via the inhibition of JNK phosphorylation. The unique property of EGCG may be used to develop a new drug-eluting stent by co-coating EGCG and paclitaxel.

  14. Magnetic field switchable dry adhesives.

    Science.gov (United States)

    Krahn, Jeffrey; Bovero, Enrico; Menon, Carlo

    2015-02-01

    A magnetic field controllable dry adhesive device is manufactured. The normal adhesion force can be increased or decreased depending on the presence of an applied magnetic field. If the magnetic field is present during the entire normal adhesion test cycle which includes both applying a preloading force and measuring the pulloff pressure, a decrease in adhesion is observed when compared to when there is no applied magnetic field. Similarly, if the magnetic field is present only during the preload portion of the normal adhesion test cycle, a decrease in adhesion is observed because of an increased stiffness of the magnetically controlled dry adhesive device. When the applied magnetic field is present during only the pulloff portion of the normal adhesion test cycle, either an increase or a decrease in normal adhesion is observed depending on the direction of the applied magnetic field.

  15. Focal adhesion kinase (FAK) mediates the induction of pro-oncogenic and fibrogenic phenotypes in hepatitis C virus (HCV)-infected cells.

    Science.gov (United States)

    Alisi, Anna; Arciello, Mario; Petrini, Stefania; Conti, Beatrice; Missale, Gabriele; Balsano, Clara

    2012-01-01

    Hepatitis C Virus (HCV) infection is one of the most common etiological factors involved in fibrosis development and its progression to hepatocellular carcinoma (HCC). The pivotal role of hepatic stellate cells (HCSs) and extracellular matrix (ECM) in fibrogenesis is now certainly accepted, while the network of molecular interactions connecting HCV is emerging as a master regulator of several biological processes including proliferation, inflammation, cytoskeleton and ECM remodeling. In this study, the effects of HCV proteins expression on liver cancer cells, both pro-invasive and pro-fibrogenic phenotypes were explored. As a model of HCV infection, we used permissive Huh7.5.1 hepatoma cells infected with JFH1-derived ccHCV. Conditioned medium from these cells was used to stimulate LX-2 cells, a line of HSCs. We found that the HCV infection of Huh7.5.1 cells decreased adhesion, increased migration and caused the delocalization of alpha-actinin from plasma membrane to cytoplasm and increased expression levels of paxillin. The treatment of LX-2 cells, with conditioned medium from HCV-infected Huh7.5.1 cells, caused an increase in cell proliferation, expression of alpha-smooth muscle actin, hyaluronic acid release and apoptosis rate measured as cleaved poly ADP-ribose polymerase (PARP). These effects were accompanied in Huh7.5.1 cells by an HCV-dependent increasing of FAK activation that physically interacts with phosphorylated paxillin and alpha-actinin, and a rising of tumor necrosis factor alpha production/release. Silencing of FAK by siRNA reverted all effects of HCV infection, both those directed on Huh7.5.1 cells, and those indirect effects on the LX-2 cells. Moreover and interestingly, FAK inhibition enhances apoptosis in HCV-conditioned LX-2 cells. In conclusion, our findings demonstrate that HCV, through FAK activation, may promote cytoskeletal reorganization and a pro-oncogenic phenotype in hepatocyte-like cells, and a fibrogenic phenotype in HSCs.

  16. Inhibition of p38 mitogen-activated protein kinase may decrease intestinal epithelial cell apoptosis and improve intestinal epithelial barrier function after ischemia- reperfusion injury

    Institute of Scientific and Technical Information of China (English)

    Shu-Yun Zheng; Xiao-Bing Fu; Jian-Guo Xu; Jing-Yu Zhao; Tong-Zhu Sun; Wei Chen

    2005-01-01

    AIM: To investigate the role of p38 mitogen-activated protein kinase in rat small intestine after ischemia-reperfusion (I/R)insult and the relationship between activation of p38 MAPK and apoptotic cell death of intestine.METHODS: Ninety Wistar rats were divided randomly into three groups, namely sham-operated group (C), I/R vehicle group (R) and SB203580 pre-treated group(S).In groups R and S, the superior mesenteric artery(SMA)was separated and occluded for 45 min, then released for reperfusion for0.25, 0.5, 1, 2, 6, 12 and 24 h. In group C, SMA was separated without occlusion. Plasma D-lactate levels were examined and histological changes were observed under a light microscope. The activity of p38 MAPK was determined by Western immunoblotting and apoptotic cells were detected by the terminal deoxynucleotidyl transferase (TdT)-mediated dUDP-biotin nick end labeling (TUNEL).RESULTS: Intestinal ischemia followed by reperfusion activated p38 MAPK, and the maximal level of activation (7.3-fold vs sham-operated group) was reached 30 min after I/R. Treatment with SB 203580, a p38 MAPK inhibitor,reduced intestinal apoptosis (26.72±3.39% vs62.50±3.08%in I/R vehicle, P<0.01) and decreased plasma D-lactate level (0.78±0.15 mmol/L in I/R vehicle vs0.42±0.17 mmol/L in SB-treated group) and improved post-ischemic intestinal histological damage.CONCLUSION: p38 MAPK plays a crucial role in the signal transduction pathway mediating post-ischemic intestinal apoptosis, and inhibition of p38 MAPK may attenuate ischemia-reperfusion injury.

  17. S-adenosyl-methionine decreases ethanol-induced apoptosis in primary hepatocyte cultures by a c-Jun N-terminal kinase activity-independent mechanism

    Institute of Scientific and Technical Information of China (English)

    María del Pilar Cabrales-Romero; Lucrecia Márquez-Rosado; Samia Fattel-Fazenda; Cristina Trejo-Solís; Evelia Arce-Popoca; Leticia Alemén-Lazarini; Saúl Villa-Trevi(n)o

    2006-01-01

    AIM: To determine the role of c-Jun N-terminal kinase (JNK) activity in ethanol-induced apoptosis and the modulation of this signaling cascade by S-Adenosylmethionine (AdoMet).METHODS: Primary hepatocyte cultures were pretreated with 100 μmol/L SP600125, a selective JNK inhibitor, 1 mL/L DMSO or 4 mmol/L AdoMet and then exposed to 100 mmo/L ethanol. Hepatocyte apoptosis was determined by the TUNEL and DNA ladder assays.JNK activity and its inhibition by SP600125 and AdoMet were determined by Western blot analysis of c-jun phosphorylation and Bid fragmentation. SP600125 and AdoMet effects on the apoptotic signaling pathway were determined by Western blot analysis of cytochrome c release and pro-caspase 3 fragmentation. The AdoMet effect on glutathione levels was measured by Ellman's method and reactive oxygen species (ROS) generation by cell cytometry.RESULTS: The exposure of hepatocytes to ethanol induced JNK activation, c-jun phosphorylation, Bid fragmentation, cytochrome c release and pro-caspase 3 cleavage; these effects were diminished by SP600125, and caused a significant decreasein ethanol-induced apoptosis (P< 0.05). AdoMet exerted an antioxidant effect maintaining glutathione levels and decreasing ROS generation, without a significant effect on JNK activity,and prevented cytochrome c release and pro-caspase 3 cleavage.CONCLUSION: The JNK signaling cascade is a key component of the proapoptotic signaling pathway induced by ethanol. JNK activation may be independent from ROS generation, since AdoMet which exerted antioxidant properties did not have a significant effect on JNK activity. JNK pathway modulator agents and AdoMet may be components of promising therapies for alcoholic liver disease (ALD) treatment.

  18. Amygdalin influences bladder cancer cell adhesion and invasion in vitro.

    Directory of Open Access Journals (Sweden)

    Jasmina Makarević

    Full Text Available The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK and total and activated focal adhesion kinase (FAK were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines may depend upon the cancer cell type.

  19. Amygdalin influences bladder cancer cell adhesion and invasion in vitro.

    Science.gov (United States)

    Makarević, Jasmina; Rutz, Jochen; Juengel, Eva; Kaulfuss, Silke; Tsaur, Igor; Nelson, Karen; Pfitzenmaier, Jesco; Haferkamp, Axel; Blaheta, Roman A

    2014-01-01

    The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type.

  20. Adhesives, silver amalgam.

    Science.gov (United States)

    1995-09-01

    The most recent advancement in silver amalgam is use of resin formulations to bond metal to tooth both chemically &/or physically, Since, historically, amalgam has been used successfully without adhesion to tooth, obvious clinical question is: Why is bonding now desirable? Two major clinical reasons to bond are: (1) Adhesive can increase fracture resistance of amalgam restored teeth & decrease cusp fractures; & (2) Seal provided by adhesive can greatly decrease, & often eliminate post-operative sensitivity. Following report summarizes CRA laboratory study of shear bond strength & sealing capability of 23 commercial adhesives used to bond 2 types of silver amalgam to tooth structure.

  1. Focal adhesion kinase (FAK mediates the induction of pro-oncogenic and fibrogenic phenotypes in hepatitis C virus (HCV-infected cells.

    Directory of Open Access Journals (Sweden)

    Anna Alisi

    Full Text Available Hepatitis C Virus (HCV infection is one of the most common etiological factors involved in fibrosis development and its progression to hepatocellular carcinoma (HCC. The pivotal role of hepatic stellate cells (HCSs and extracellular matrix (ECM in fibrogenesis is now certainly accepted, while the network of molecular interactions connecting HCV is emerging as a master regulator of several biological processes including proliferation, inflammation, cytoskeleton and ECM remodeling. In this study, the effects of HCV proteins expression on liver cancer cells, both pro-invasive and pro-fibrogenic phenotypes were explored. As a model of HCV infection, we used permissive Huh7.5.1 hepatoma cells infected with JFH1-derived ccHCV. Conditioned medium from these cells was used to stimulate LX-2 cells, a line of HSCs. We found that the HCV infection of Huh7.5.1 cells decreased adhesion, increased migration and caused the delocalization of alpha-actinin from plasma membrane to cytoplasm and increased expression levels of paxillin. The treatment of LX-2 cells, with conditioned medium from HCV-infected Huh7.5.1 cells, caused an increase in cell proliferation, expression of alpha-smooth muscle actin, hyaluronic acid release and apoptosis rate measured as cleaved poly ADP-ribose polymerase (PARP. These effects were accompanied in Huh7.5.1 cells by an HCV-dependent increasing of FAK activation that physically interacts with phosphorylated paxillin and alpha-actinin, and a rising of tumor necrosis factor alpha production/release. Silencing of FAK by siRNA reverted all effects of HCV infection, both those directed on Huh7.5.1 cells, and those indirect effects on the LX-2 cells. Moreover and interestingly, FAK inhibition enhances apoptosis in HCV-conditioned LX-2 cells. In conclusion, our findings demonstrate that HCV, through FAK activation, may promote cytoskeletal reorganization and a pro-oncogenic phenotype in hepatocyte-like cells, and a fibrogenic phenotype in

  2. Carnosol inhibits cell adhesion molecules and chemokine expression by tumor necrosis factor-α in human umbilical vein endothelial cells through the nuclear factor-κB and mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Yao, Hui; Chen, Yufeng; Zhang, Longjuan; He, Xiaosheng; He, Xiaowen; Lian, Lei; Wu, Xiaojian; Lan, Ping

    2014-02-01

    Inflammatory bowel diseases (IBD) are gastrointestinal disorders associated with chronic inflammatory processes. Carnosol has been demonstrated to possess anti-inflammatory properties. This study examined the suppressive effect of carnosol on the expression of cell adhesion molecules (CAMs) and chemokines in human umbilical vein endothelial cells (HUVECs) and the possible underlying mechanism. The effect of carnosol on CAM and chemokine expression in HUVECs was identified by western blotting and ELISA, respectively. nuclear factor (NF)-κB activation of HUVECs was analyzed using the TransAM NF-κB Family kit. The effect of carnosol on the tumor necrosis factor (TNF)-α-induced activation of the NF-κB and mitogen-activated protein kinase (MAPK) pathways, and was subsequently analyzed using western blotting. Carnosol not only inhibited TNF-α-induced protein expression of intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1 and E-selectin in HUVECs, but also suppressed interleukin (IL)-8 and monocyte chemoattractant protein (MCP)-1 expression. In addition, carnosol inhibited the TNF-α-induced phosphorylation of p-65 and IκB-α, as well as the activation of NF-κB. The same result was observed in TNF-α-stimulated phosphorylation of ERK1/2 and p-38. It was demonstrated that carnosol inhibited TNF-α-induced CAM and chemokine expression in HUVECs. The underlying mechanism may be associated with the blocking of the NF-κB and MAPK pathways. These results indicate that carnosol may be a novel therapeutic agent for targeting endothelial cells in IBDs.

  3. Regulation of G protein-linked guanine nucleotide exchange factors for Rho, PDZ-RhoGEF, and LARG by tyrosine phosphorylation: evidence of a role for focal adhesion kinase.

    Science.gov (United States)

    Chikumi, Hiroki; Fukuhara, Shigetomo; Gutkind, J Silvio

    2002-04-05

    A recently identified family of guanine nucleotide exchange factors for Rho that includes PDZ-RhoGEF, LARG, and p115RhoGEF exhibits a unique structural feature consisting in the presence of area of similarity to regulators of G protein signaling (RGS). This RGS-like (RGL) domain provides a structural motif by which heterotrimeric G protein alpha subunits of the Galpha(12) family can bind and regulate the activity of RhoGEFs. Hence, these newly discovered RGL domain-containing RhoGEFs provide a direct link from Galpha(12) and Galpha(13) to Rho. Recently available data suggest, however, that tyrosine kinases can regulate the ability of G protein-coupled receptors (GPCRs) to stimulate Rho, although the underlying molecular mechanisms are still unknown. Here, we found that the activation of thrombin receptors endogenously expressed in HEK-293T cells leads to a remarkable increase in the levels of GTP-bound Rho within 1 min (11-fold) and a more limited but sustained activation (4-fold) thereafter, which lasts even for several hours. Interestingly, tyrosine kinase inhibitors did not affect the early phase of Rho activation, immediately after thrombin addition, but diminished the levels of GTP-bound Rho during the delayed phase. As thrombin receptors stimulate focal adhesion kinase (FAK) potently, we explored whether this non-receptor tyrosine kinase participates in the activation of Rho by GPCRs. We obtained evidence that FAK can be activated by thrombin, Galpha(12), Galpha(13), and Galpha(q) through both Rho-dependent and Rho-independent mechanisms and that PDZ-RhoGEF and LARG can in turn be tyrosine-phosphorylated through FAK in response to thrombin, thereby enhancing the activation of Rho in vivo. These data indicate that FAK may act as a component of a positive feedback loop that results in the sustained activation of Rho by GPCRs, thus providing evidence of the existence of a novel biochemical route by which tyrosine kinases may regulate the activity of Rho through

  4. The Src family kinases: distinct functions of c-Src, Yes, and Fyn in the liver.

    Science.gov (United States)

    Reinehr, Roland; Sommerfeld, Annika; Häussinger, Dieter

    2013-04-01

    The Src family kinases Yes, Fyn, and c-Src play a pivotal role in regulating diverse liver functions such as bile flow, proteolysis, apoptosis, and proliferation and are regulated by anisoosmotic cell volume changes, death receptor ligands, and bile acids. For example, cell swelling leads to an integrin-sensed and focal adhesion kinase-mediated activation of c-Src-triggering choleresis, proteolysis inhibition, regulatory volume decrease via p38MAPK and proliferation via the activation of the epidermal growth factor receptor and extracellular regulated kinases 1 and 2. In contrast, hepatocyte shrinkage generates an almost instantaneous oxidative stress response that triggers the activation of c-Jun N-terminal kinase and the Src family kinases Fyn and Yes. Whereas Fyn activation mediates cholestasis, Yes triggers CD95 activation and apoptosis. This review will discuss the role of Src family kinases in the regulation of liver function with emphasis on their role in osmo-signaling and bile acid signaling.

  5. Tyrosine kinase BMX phosphorylates phosphotyrosine-primed motif mediating the activation of multiple receptor tyrosine kinases.

    Science.gov (United States)

    Chen, Sen; Jiang, Xinnong; Gewinner, Christina A; Asara, John M; Simon, Nicholas I; Cai, Changmeng; Cantley, Lewis C; Balk, Steven P

    2013-05-28

    The nonreceptor tyrosine kinase BMX (bone marrow tyrosine kinase gene on chromosome X) is abundant in various cell types and activated downstream of phosphatidylinositol-3 kinase (PI3K) and the kinase Src, but its substrates are unknown. Positional scanning peptide library screening revealed a marked preference for a priming phosphorylated tyrosine (pY) in the -1 position, indicating that BMX substrates may include multiple tyrosine kinases that are fully activated by pYpY sites in the kinase domain. BMX phosphorylated focal adhesion kinase (FAK) at Tyr⁵⁷⁷ subsequent to its Src-mediated phosphorylation at Tyr⁵⁷⁶. Loss of BMX by RNA interference or by genetic deletion in mouse embryonic fibroblasts (MEFs) markedly impaired FAK activity. Phosphorylation of the insulin receptor in the kinase domain at Tyr¹¹⁸⁹ and Tyr¹¹⁹⁰, as well as Tyr¹¹⁸⁵, and downstream phosphorylation of the kinase AKT at Thr³⁰⁸ were similarly impaired by BMX deficiency. However, insulin-induced phosphorylation of AKT at Ser⁴⁷³ was not impaired in Bmx knockout MEFs or liver tissue from Bmx knockout mice, which also showed increased insulin-stimulated glucose uptake, possibly because of decreased abundance of the phosphatase PHLPP (PH domain leucine-rich repeat protein phosphatase). Thus, by identifying the pYpY motif as a substrate for BMX, our findings suggest that BMX functions as a central regulator among multiple signaling pathways mediated by tyrosine kinases.

  6. Microparticles engineered to highly express peroxisome proliferator-activated receptor-γ decreased inflammatory mediator production and increased adhesion of recipient monocytes.

    Directory of Open Access Journals (Sweden)

    Julie Sahler

    also changed monocyte mRNA levels of several genes including those under PPARγ control. Overall, the delivery of PPARγ from microparticles to human monocytes influenced gene expression, decreased inflammatory mediator production and increased monocyte adherence. These results support the concept that the composition of blood microparticles has a profound impact on the function of cells with which they interact, and likely plays a role in vascular inflammation.

  7. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2003-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well...... to rewriting on arbitrary adhesive categories....

  8. Aldosterone stimulates nuclear factor-kappa B activity and transcription of intercellular adhesion molecule-1 and connective tissue growth factor in rat mesangial cells via serum- and glucocorticoid-inducible protein kinase-1.

    Science.gov (United States)

    Terada, Yoshio; Ueda, Satoko; Hamada, Kazu; Shimamura, Yoshiko; Ogata, Koji; Inoue, Kosuke; Taniguchi, Yoshinori; Kagawa, Toru; Horino, Taro; Takao, Toshihiro

    2012-02-01

    Several clinical and experimental data support the hypothesis that aldosterone contributes to the progression of renal injury. To determine the signaling pathway of aldosterone in relation to fibrosis and inflammation in mesangial cells, we investigated the effects of aldosterone on expression and activation of serum- and glucocorticoid-inducible protein kinase-1 (SGK1), the activation of nuclear factor-kappa B (NF-κB activation, and the expressions of intercellular adhesion molecule-1 (ICAM-1) and connective tissue growth factor (CTGF). Aldosterone stimulated SGK1 expression, phosphorylation (Ser-256), and kinase activity. The increments of phosphorylation and expression of SGK1 induced by aldosterone were inhibited by mineralocorticoid receptor (MR) inhibitor (eplerenone). Aldosterone stimulated NF-κB activity measured by NF-κB responsive elements, luciferase assay, and the levels of inhibitor of kappa B (IκB) phosphorylation. This aldosterone-induced activation of NF-κB was inhibited by the transfection of dominant-negative SGK1. Furthermore, aldosterone augmented the promoter activities and protein expressions of ICAM-1 and CTGF. The effects of aldosterone on ICAM-1 and CTGF promoter activities and protein expressions were inhibited by the transfection of dominant-negative SGK1 and dominant-negative IκBα. We also found that the MR antagonist significantly ameliorated the glomerular injury and enhancements in SGK1, ICAM-1, and CTGF expressions induced by 1% sodium chloride and aldosterone in vivo. In conclusion, our findings suggest that aldosterone stimulates ICAM-1 and CTGF transcription via activation of SGK1 and NF-κB, which may be involved in the progression of aldosterone-induced mesangial fibrosis and inflammation. MR antagonists may serve as useful therapeutic targets for the treatment of glomerular inflammatory disease.

  9. The Neural Cell Adhesion Molecule (NCAM) Promotes Clustering and Activation of EphA3 Receptors in GABAergic Interneurons to Induce Ras Homolog Gene Family, Member A (RhoA)/Rho-associated protein kinase (ROCK)-mediated Growth Cone Collapse.

    Science.gov (United States)

    Sullivan, Chelsea S; Kümper, Maike; Temple, Brenda S; Maness, Patricia F

    2016-12-16

    Establishment of a proper balance of excitatory and inhibitory connectivity is achieved during development of cortical networks and adjusted through synaptic plasticity. The neural cell adhesion molecule (NCAM) and the receptor tyrosine kinase EphA3 regulate the perisomatic synapse density of inhibitory GABAergic interneurons in the mouse frontal cortex through ephrin-A5-induced growth cone collapse. In this study, it was demonstrated that binding of NCAM and EphA3 occurred between the NCAM Ig2 domain and EphA3 cysteine-rich domain (CRD). The binding interface was further refined through molecular modeling and mutagenesis and shown to be comprised of complementary charged residues in the NCAM Ig2 domain (Arg-156 and Lys-162) and the EphA3 CRD (Glu-248 and Glu-264). Ephrin-A5 induced co-clustering of surface-bound NCAM and EphA3 in GABAergic cortical interneurons in culture. Receptor clustering was impaired by a charge reversal mutation that disrupted NCAM/EphA3 association, emphasizing the importance of the NCAM/EphA3 binding interface for cluster formation. NCAM enhanced ephrin-A5-induced EphA3 autophosphorylation and activation of RhoA GTPase, indicating a role for NCAM in activating EphA3 signaling through clustering. NCAM-mediated clustering of EphA3 was essential for ephrin-A5-induced growth cone collapse in cortical GABAergic interneurons, and RhoA and a principal effector, Rho-associated protein kinase, mediated the collapse response. This study delineates a mechanism in which NCAM promotes ephrin-A5-dependent clustering of EphA3 through interaction of the NCAM Ig2 domain and the EphA3 CRD, stimulating EphA3 autophosphorylation and RhoA signaling necessary for growth cone repulsion in GABAergic interneurons in vitro, which may extend to remodeling of axonal terminals of interneurons in vivo.

  10. RP1 is a phosphorylation target of CK2 and is involved in cell adhesion.

    Directory of Open Access Journals (Sweden)

    Frank Stenner

    Full Text Available RP1 (synonym: MAPRE2, EB2 is a member of the microtubule binding EB1 protein family, which interacts with APC, a key regulatory molecule in the Wnt signalling pathway. While the other EB1 proteins are well characterized the cellular function and regulation of RP1 remain speculative to date. However, recently RP1 has been implicated in pancreatic cancerogenesis. CK2 is a pleiotropic kinase involved in adhesion, proliferation and anti-apoptosis. Overexpression of protein kinase CK2 is a hallmark of many cancers and supports the malignant phenotype of tumor cells. In this study we investigate the interaction of protein kinase CK2 with RP1 and demonstrate that CK2 phosphorylates RP1 at Ser(236 in vitro. Stable RP1 expression in cell lines leads to a significant cleavage and down-regulation of N-cadherin and impaired adhesion. Cells expressing a Phospho-mimicking point mutant RP1-ASP(236 show a marked decrease of adhesion to endothelial cells under shear stress. Inversely, we found that the cells under shear stress downregulate endogenous RP1, most likely to improve cellular adhesion. Accordingly, when RP1 expression is suppressed by shRNA, cells lacking RP1 display significantly increased cell adherence to surfaces. In summary, RP1 phosphorylation at Ser(236 by CK2 seems to play a significant role in cell adhesion and might initiate new insights in the CK2 and EB1 family protein association.

  11. RP1 Is a Phosphorylation Target of CK2 and Is Involved in Cell Adhesion

    Science.gov (United States)

    Göttig, Stephan; Henschler, Reinhard; Markuly, Norbert; Kleber, Sascha; Faust, Michael; Mischo, Axel; Bauer, Stefan; Zweifel, Martin; Knuth, Alexander; Renner, Christoph; Wadle, Andreas

    2013-01-01

    RP1 (synonym: MAPRE2, EB2) is a member of the microtubule binding EB1 protein family, which interacts with APC, a key regulatory molecule in the Wnt signalling pathway. While the other EB1 proteins are well characterized the cellular function and regulation of RP1 remain speculative to date. However, recently RP1 has been implicated in pancreatic cancerogenesis. CK2 is a pleiotropic kinase involved in adhesion, proliferation and anti-apoptosis. Overexpression of protein kinase CK2 is a hallmark of many cancers and supports the malignant phenotype of tumor cells. In this study we investigate the interaction of protein kinase CK2 with RP1 and demonstrate that CK2 phosphorylates RP1 at Ser236 in vitro. Stable RP1 expression in cell lines leads to a significant cleavage and down-regulation of N-cadherin and impaired adhesion. Cells expressing a Phospho-mimicking point mutant RP1-ASP236 show a marked decrease of adhesion to endothelial cells under shear stress. Inversely, we found that the cells under shear stress downregulate endogenous RP1, most likely to improve cellular adhesion. Accordingly, when RP1 expression is suppressed by shRNA, cells lacking RP1 display significantly increased cell adherence to surfaces. In summary, RP1 phosphorylation at Ser236 by CK2 seems to play a significant role in cell adhesion and might initiate new insights in the CK2 and EB1 family protein association. PMID:23844040

  12. cGMP-dependent protein kinase type II knockout mice exhibit working memory impairments, decreased repetitive behavior, and increased anxiety-like traits.

    Science.gov (United States)

    Wincott, Charlotte M; Abera, Sinedu; Vunck, Sarah A; Tirko, Natasha; Choi, Yoon; Titcombe, Roseann F; Antoine, Shannon O; Tukey, David S; DeVito, Loren M; Hofmann, Franz; Hoeffer, Charles A; Ziff, Edward B

    2014-10-01

    Neuronal activity regulates AMPA receptor trafficking, a process that mediates changes in synaptic strength, a key component of learning and memory. This form of plasticity may be induced by stimulation of the NMDA receptor which, among its activities, increases cyclic guanosine monophosphate (cGMP) through the nitric oxide synthase pathway. cGMP-dependent protein kinase type II (cGKII) is ultimately activated via this mechanism and AMPA receptor subunit GluA1 is phosphorylated at serine 845. This phosphorylation contributes to the delivery of GluA1 to the synapse, a step that increases synaptic strength. Previous studies have shown that cGKII-deficient mice display striking spatial learning deficits in the Morris Water Maze compared to wild-type littermates as well as lowered GluA1 phosphorylation in the postsynaptic density of the prefrontal cortex (Serulle et al., 2007; Wincott et al., 2013). In the current study, we show that cGKII knockout mice exhibit impaired working memory as determined using the prefrontal cortex-dependent Radial Arm Maze (RAM). Additionally, we report reduced repetitive behavior in the Marble Burying task (MB), and heightened anxiety-like traits in the Novelty Suppressed Feeding Test (NSFT). These data suggest that cGKII may play a role in the integration of information that conveys both anxiety-provoking stimuli as well as the spatial and environmental cues that facilitate functional memory processes and appropriate behavioral response.

  13. A proteomic approach links decreased pyruvate kinase M2 expression to oxaliplatin resistance in patients with colorectal cancer and in human cell lines.

    Science.gov (United States)

    Martinez-Balibrea, Eva; Plasencia, Carmen; Ginés, Alba; Martinez-Cardús, Anna; Musulén, Eva; Aguilera, Rodrigo; Manzano, José Luis; Neamati, Nouri; Abad, Albert

    2009-04-01

    We aimed to gain further understanding of the molecular mechanisms involved in oxaliplatin resistance in colorectal cancer by using a proteomic approach. A 5-fold oxaliplatin-resistant cell line, HTOXAR3, was compared with its parental cell line, HT29, using two-dimensional PAGE. Mass spectrometry, Western blot, and real-time quantitative PCR confirmed the down-regulation of pyruvate kinase M2 (PK-M2) in HTOXAR3 cells. In a panel of eight colorectal cancer cell lines, we found a negative correlation between oxaliplatin resistance and PK-M2 mRNA levels (Spearman r=-0.846, P=0.008). Oxaliplatin exposure in both HT29 and HTOXAR3 led to PK-M2 mRNA up-regulation. PK-M2 mRNA levels were measured by real-time quantitative PCR in 41 tumors treated with oxaliplatin/5-fluorouracil. Tumors with the lowest PK-M2 levels attained the lowest response rates (20% versus 64.5%, P=0.026). High PK-M2 levels were associated with high p53 levels (P=0.032). In conclusion, the data provided clearly link PK-M2 expression and oxaliplatin resistance mechanisms and further implicate PK-M2 as a predictive marker of response in patients with oxaliplatin-treated colorectal cancer.

  14. Role of cell adhesion signal molecules in hepatocellular carcinoma cell apoptosis

    Institute of Scientific and Technical Information of China (English)

    Jian-Min Su; Li-Ying Wang; Yu-Long Liang; Xi-Liang Zha

    2005-01-01

    AIM: Cell adhesion molecules and their signal molecules play a very important role in carcinogenesis. The aim of this study is to elucidate the role of these molecules and the signal molecules of integrins and E-cadherins, such as (focal adhesion kinase) FAK, (integrin linked kinase)ILK, and β-catenin in hepatocellular carcinoma cell apoptosis.METHODS: We first synthesized the small molecular compound, S-(1,2-dichlorovinyl)-L-cysteine (DCVC), and identified it, by element analysis and 1H NMR. To establish the apoptosis model of the SMMC-7721 hepatocellular carcinoma cell, we treated cells with DCVC in EBSS for different concentrations or for various length times in the presence of 20 μmol/L N,N-diphenyl-p-phenylenediamine,which blocks necrotic cell death and identified this model by flow cytometry and DNA ladder. Then we studied the changes of FAK, ILK, β-catenin, and PKB in this apoptotic model by Western blot.RESULTS: We found that the loss or decrease of cell adhesion signal molecules is an important reason in apoptosis of SMMC-7721 hepatocellular carcinoma cell and the apoptosis of SMMC-7721 cell was preceded by the loss or decrease of FAK, ILK, PKB, and β-catenin or the damage of cell-matrix and cell-cell adhesion.CONCLUSION: Our results suggested that the decrease of adhesion signal molecules, FAK, ILK, PKB, and β-catenin,could induce hepatocellular carcinoma cell apoptosis.

  15. Adhesion of ZAP-70+ chronic lymphocytic leukemia cells to stromal cells is enhanced by cytokines and blocked by inhibitors of the PI3-kinase pathway.

    Science.gov (United States)

    Lafarge, Sandrine T; Johnston, James B; Gibson, Spencer B; Marshall, Aaron J

    2014-01-01

    CLL cell survival and proliferation is enhanced through direct contact with supporting cells present in lymphoid tissues. PI3Ks are critical signal transduction enzymes controlling B cell survival and activation. PI3K inhibitors have entered clinical trials and show promising therapeutic activity; however, it is unclear whether PI3K inhibitor drugs differentially affect ZAP-70 positive versus negative CLL cells or target specific microenvironmental interactions. Here we provide evidence that CD40L+IL-4, IL-8 or IL-6 enhance adhesion to stromal cells, with IL-6 showing a selective effect on ZAP-70 positive cells. Stimulatory effects of IL-8 or IL-6 are fully reversed by PI3K inhibition, while the effects of CD40L+IL-4 are partially reversed. While CD40L+IL-4 is the only stimulation increasing CLL cell survival for all patient groups, IL-6 protects ZAP-70 positive cells from cell death induced by PI3K inhibition. Altogether, our results indicate that targeting the PI3K pathway can reverse protective CLL-microenvironment interactions in both ZAP-70 positive and negative CLL despite their differences in cytokine responsiveness.

  16. Endothelial PI 3-kinase activity regulates lymphocyte diapedesis.

    Science.gov (United States)

    Nakhaei-Nejad, Maryam; Hussain, Amer M; Zhang, Qiu-Xia; Murray, Allan G

    2007-12-01

    Lymphocyte recruitment to sites of inflammation involves a bidirectional series of cues between the endothelial cell (EC) and the leukocyte that culminate in lymphocyte migration into the tissue. Remodeling of the EC F-actin cytoskeleton has been observed after leukocyte adhesion, but the signals to the EC remain poorly defined. We studied the dependence of peripheral blood lymphocyte transendothelial migration (TEM) through an EC monolayer in vitro on EC phosphatidylinositol 3-kinase (PI 3-kinase) activity. Lymphocytes were perfused over cytokine-activated EC using a parallel-plate laminar flow chamber. Inhibition of EC PI 3-kinase activity using LY-294002 or wortmannin decreased lymphocyte TEM (48 +/- 6 or 34 +/- 7%, respectively, vs. control; mean +/- SE; P structure" after intercellular adhesion molecule-1 ligation, whereas this was inhibited by jasplakinolide treatment. A similar fraction of lymphocytes migrated on control or LY-294002-treated EC and localized to interendothelial junctions. However, lymphocytes failed to extend processes below the level of vascular endothelial (VE)-cadherin on LY-294002-treated EC. Together these observations indicate that EC PI 3-kinase activity and F-actin remodeling are required during lymphocyte diapedesis and identify a PI 3-kinase-dependent step following initial separation of the VE-cadherin barrier.

  17. Decreased spontaneous activity in AMPK alpha 2 muscle specific kinase dead mice is not caused by changes in brain dopamine metabolism

    DEFF Research Database (Denmark)

    Møller, Lisbeth Liliendal Valbjørn; Sylow, Lykke; Gøtzsche, Casper René

    2016-01-01

    capacity and display reduced voluntary wheel running activity. Striatal content of dopamine and its metabolites were measured under basal physiological conditions and after cocaine-induced dopamine efflux from the ventral striatum by in vivo microdialysis. Moreover, cocaine-induced locomotor activity...... to WT when treated with saline or cocaine, respectively, but the increase induced by cocaine was similar in AMPK α2 KD and WT mice. The efflux of dopamine in ventral striatum after cocaine treatment increased similarly by 2.5-fold in the two genotypes, and basal levels of dopamine and its metabolites...... DOPAC and HVA were also similar between genotypes. These findings show that decreased AMPK activity in muscle leads to decreased voluntary activity which is not due to secondary abnormalities in dopamine levels in the ventral striatum or sensitivity to cocaine. Thus, decreased voluntary activity in AMPK...

  18. Spreading depolarization in the brain of Drosophila is induced by inhibition of the Na+/K+-ATPase and mitigated by a decrease in activity of protein kinase G.

    Science.gov (United States)

    Spong, Kristin E; Rodríguez, Esteban C; Robertson, R Meldrum

    2016-09-01

    Spreading depolarization (SD) is characterized by a massive redistribution of ions accompanied by an arrest in electrical activity that slowly propagates through neural tissue. It has been implicated in numerous human pathologies, including migraine, stroke, and traumatic brain injury, and thus the elucidation of control mechanisms underlying the phenomenon could have many health benefits. Here, we demonstrate the occurrence of SD in the brain of Drosophila melanogaster, providing a model system, whereby cellular mechanisms can be dissected using molecular genetic approaches. Propagating waves of SD were reliably induced by disrupting the extracellular potassium concentration ([K(+)]o), either directly or by inhibition of the Na(+)/K(+)-ATPase with ouabain. The disturbance was monitored by recording the characteristic surges in [K(+)]o using K(+)-sensitive microelectrodes or by monitoring brain activity by measuring direct current potential. With the use of wild-type flies, we show that young adults are more resistant to SD compared with older adults, evidenced by shorter bouts of SD activity and attenuated [K(+)]o disturbances. Furthermore, we show that the susceptibility to SD differs between wild-type flies and w1118 mutants, demonstrating that our ouabain model is influenced by genetic strain. Lastly, flies with low levels of protein kinase G (PKG) had increased latencies to onset of both ouabain-induced SD and anoxic depolarization compared with flies with higher levels. Our findings implicate the PKG pathway as a modulator of SD in the fly brain, and given the conserved nature of the signaling pathway, it could likely play a similar role during SD in the mammalian central nervous system.

  19. EPS-SJ exopolisaccharide produced by the strain Lactobacillus paracasei subsp. paracasei BGSJ2-8 is involved in adhesion to epithelial intestinal cells and decrease on E. coli association to Caco-2 cells

    Directory of Open Access Journals (Sweden)

    Milica eZivkovic

    2016-03-01

    Full Text Available The aim of this study was to determine the role of an exopolysaccharide produced by natural dairy isolate Lactobacillus paracasei subsp. paracasei BGSJ2-8, in the adhesion to intestinal epithelial cells and a decrease in E. coli’s association with Caco-2 cells. Annotation of the BGSJ2-8 genome showed the presence of a gene cluster, epsSJ, which encodes the biosynthesis of the strain-specific exopolysaccharide EPS-SJ, detected as two fractions (P1 and P2 by size exclusion chromatography (SEC coupled with multi-angle laser light scattering (MALLS detection. SEC-MALLS analysis revealed that an EPS-SJ‒ mutant (EPS7, obtained by insertion mutagenesis of the glps_2198 gene encoding primary glycosyltransferase does not produce the P2 fraction of EPS-SJ. Transmission electron microscopy showed that EPS7 mutant has a thinner cell wall compared to the EPS-SJ+ strain BGSJ2-83 (a plasmid free-derivative of BGSJ2-8. Interestingly, strain BGSJ2-83 showed higher adhesion to Caco-2 epithelial intestinal cell line than the EPS7 mutant. Accordingly, BGSJ2-83 effectively reduced E. coli ATCC25922’s association with Caco-2 cells, while EPS7 did not show statistically significant differences. In addition, the effect of EPS-SJ on the proliferation of lymphocytes in gastrointestinal associated lymphoid tissue (GALT was tested and the results showed that the reduction of GALT lymphocyte proliferation was higher by BGSJ2-83 than by the mutant. To the best of our knowledge this is the first report indicating that the presence of EPS (EPS-SJ on the surface of lactobacilli can improve communication between bacteria and intestinal epithelium, implying its possible role in gut colonization.

  20. Lipid Raft is required for PSGL-1 ligation induced HL-60 cell adhesion on ICAM-1.

    Directory of Open Access Journals (Sweden)

    Tingshuang Xu

    Full Text Available P-selectin glycoprotein ligand-1 (PSGL-1 and integrins are adhesion molecules that play critical roles in host defense and innate immunity. PSGL-1 mediates leukocyte rolling and primes leukocytes for integrin-mediated adhesion. However, the mechanism that PSGL-1 as a rolling receptor in regulating integrin activation has not been well characterized. Here, we investigate the function of lipid raft in regulating PSGL-1 induced β2 integrin-mediated HL-60 cells adhesion. PSGL-1 ligation with antibody enhances the β2 integrin activation and β2 integrin-dependent adhesion to ICAM-1. Importantly, with the treatment of methyl-β-cyclodextrin (MβCD, we confirm the role of lipid raft in regulating the activation of β2 integrin. Furthermore, we find that the protein level of PSGL-1 decreased in raft fractions in MβCD treated cells. PSGL-1 ligation induces the recruitment of spleen tyrosine kinase (Syk, a tyrosine kinase and Vav1 (the pivotal downstream effector of Syk signaling pathway involved in cytoskeleton regulation to lipid raft. Inhibition of Syk activity with pharmacologic inhibitor strongly reduces HL-60 cells adhesion, implicating Syk is crucial for PSGL-1 mediated β2 integrin activation. Taken together, we report that ligation of PSGL-1 on HL-60 cells activates β2 integrin, for which lipid raft integrity and Syk activation are responsible. These findings have shed new light on the mechanisms that connect leukocyte initial rolling with subsequent adhesion.

  1. Reduction of atherosclerosis in cholesterol-fed rabbits and decrease of expressions of intracellular adhesion molecule-1 and vascular endothelial growth factor in foam cells by a water-soluble fraction of Polygonum multiflorum.

    Science.gov (United States)

    Yang, Peng-Yuan; Almofti, Mohamad Radwan; Lu, Ling; Kang, Hui; Zhang, Jing; Li, Tie-Jun; Rui, Yao-Cheng; Sun, Lian-Na; Chen, Wan-Sheng

    2005-11-01

    Polygonum multiflorum stilbeneglycoside (PMS) is a water-soluble fraction of Polygonum multiflorum Thunb., one of the most famous tonic traditional Chinese medicines, that has protective effects on the cardiovascular system. The purpose of the present study is to elucidate the effects of PMS on macrophage-derived foam cell functions and the reduction of severity of atherosclerosis in hypercholesterolemic New Zealand White (NZW) rabbits. NZW rabbits were fed for 12 weeks with a normal diet, a high cholesterol diet, or a high cholesterol diet associated with irrigation with different doses of PMS (25, 50, or 100 mg/kg). Treatment of NZW rabbits fed with high cholesterol diet with 100 mg/kg PMS attenuated the increase in plasma cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and plasma triglyceride. Treatment with 50 and 100 mg/kg PMS caused 43% and 60% decrease in atherosclerotic lesioned area ratio to total surface area, respectively. In U937 foam cells, PMS could decrease the high expression of intercellular adhesion molecule (ICAM)-1 protein and the vascular endothelial growth factor (VEGF) protein levels in the medium induced by oxidized lipoprotein when analyzed by flow cytometry. The results proved that PMS is a powerful agent against atherosclerosis and that PMS action could possibly be through the inhibition of the expression of ICAM-1 and VEGF in foam cells.

  2. Serine34 phosphorylation of RHO guanine dissociation inhibitor (RHOGDI{alpha}) links signaling from conventional protein kinase C to RHO GTPase in cell adhesion

    DEFF Research Database (Denmark)

    Dovas, Athanassios; Choi, Youngsil; Yoneda, Atsuko;

    2010-01-01

    , resulting in a specific decrease in affinity for RhoA, but not Rac1 or cdc42. The mechanism of RhoGDIalpha phosphorylation is distinct, requiring PKCalpha and phosphatidylinositol 4,5 bisphosphate, consistent with recent evidence that the inositide can activate, localize and orient PKCalpha in membranes...

  3. Adhesive Categories

    DEFF Research Database (Denmark)

    Lack, Stephen; Sobocinski, Pawel

    2004-01-01

    We introduce adhesive categories, which are categories with structure ensuring that pushouts along monomorphisms are well-behaved. Many types of graphical structures used in computer science are shown to be examples of adhesive categories. Double-pushout graph rewriting generalises well to rewrit...

  4. Smooth muscle hyperplasia due to loss of smooth muscle α-actin is driven by activation of focal adhesion kinase, altered p53 localization and increased levels of platelet-derived growth factor receptor-β.

    Science.gov (United States)

    Papke, Christina L; Cao, Jiumei; Kwartler, Callie S; Villamizar, Carlos; Byanova, Katerina L; Lim, Soon-Mi; Sreenivasappa, Harini; Fischer, Grant; Pham, John; Rees, Meredith; Wang, Miranda; Chaponnier, Christine; Gabbiani, Giulio; Khakoo, Aarif Y; Chandra, Joya; Trache, Andreea; Zimmer, Warren; Milewicz, Dianna M

    2013-08-01

    Mutations in ACTA2, encoding the smooth muscle cell (SMC)-specific isoform of α-actin (α-SMA), cause thoracic aortic aneurysms and dissections and occlusive vascular diseases, including early onset coronary artery disease and stroke. We have shown that occlusive arterial lesions in patients with heterozygous ACTA2 missense mutations show increased numbers of medial or neointimal SMCs. The contribution of SMC hyperplasia to these vascular diseases and the pathways responsible for linking disruption of α-SMA filaments to hyperplasia are unknown. Here, we show that the loss of Acta2 in mice recapitulates the SMC hyperplasia observed in ACTA2 mutant SMCs and determine the cellular pathways responsible for SMC hyperplasia. Acta2(-/-) mice showed increased neointimal formation following vascular injury in vivo, and SMCs explanted from these mice demonstrated increased proliferation and migration. Loss of α-SMA induced hyperplasia through focal adhesion (FA) rearrangement, FA kinase activation, re-localization of p53 from the nucleus to the cytoplasm and increased expression and ligand-independent activation of platelet-derived growth factor receptor beta (Pdgfr-β). Disruption of α-SMA in wild-type SMCs also induced similar cellular changes. Imatinib mesylate inhibited Pdgfr-β activation and Acta2(-/-) SMC proliferation in vitro and neointimal formation with vascular injury in vivo. Loss of α-SMA leads to SMC hyperplasia in vivo and in vitro through a mechanism involving FAK, p53 and Pdgfr-β, supporting the hypothesis that SMC hyperplasia contributes to occlusive lesions in patients with ACTA2 missense mutations.

  5. Inhibition of tumor vasculogenic mimicry and prolongation of host survival in highly aggressive gallbladder cancers by norcantharidin via blocking the ephrin type a receptor 2/focal adhesion kinase/paxillin signaling pathway.

    Directory of Open Access Journals (Sweden)

    Hui Wang

    Full Text Available Vasculogenic mimicry (VM is a newly-defined tumor microcirculation pattern in highly aggressive malignant tumors. We recently reported tumor growth and VM formation of gallbladder cancers through the contribution of the ephrin type a receptor 2 (EphA2/focal adhesion kinase (FAK/Paxillin signaling pathways. In this study, we further investigated the anti-VM activity of norcantharidin (NCTD as a VM inhibitor for gallbladder cancers and the underlying mechanisms. In vivo and in vitro experiments to determine the effects of NCTD on tumor growth, host survival, VM formation of GBC-SD nude mouse xenografts, and vasculogenic-like networks, malignant phenotypes i.e., proliferation, apoptosis, invasion and migration of GBC-SD cells. Expression of VM signaling-related markers EphA2, FAK and Paxillin in vivo and in vitro were examined by immunofluorescence, western blotting and real-time polymerase chain reaction (RT-PCR, respectively. The results showed that after treatment with NCTD, GBC-SD cells were unable to form VM structures when injecting into nude mouse, growth of the xenograft was inhibited and these observations were confirmed by facts that VM formation by three-dimensional (3-D matrix, proliferation, apoptosis, invasion, migration of GBC-SD cells were affected; and survival time of the xenograft mice was prolonged. Furthermore, expression of EphA2, FAK and Paxillin proteins/mRNAs of the xenografts was downregulated. Thus, we concluded that NCTD has potential anti-VM activity against human gallbladder cancers; one of the underlying mechanisms may be via blocking the EphA2/FAK/Paxillin signaling pathway.

  6. G-Protein Inwardly Rectifying Potassium Channel 1 (GIRK1 Knockdown Decreases Beta-Adrenergic, MAP Kinase and Akt Signaling in the MDA-MB-453 Breast Cancer Cell Line

    Directory of Open Access Journals (Sweden)

    Michael W. Hance

    2008-01-01

    Full Text Available Previous data from our laboratory have indicated that there is a functional link between the beta-adrenergic receptor signaling pathway and the G-protein inwardly rectifying potassium channel (GIRK1 in breast cancer cell lines and that these pathways are involved in growth regulation of these cells. To determine functionality, MDA-MB-453 breast cancer cells were stimulated with ethanol, known to open GIRK channels. Decreased GIRK1 protein levels were seen after treatment with 0.12% ethanol. In addition, serum-free media completely inhibited GIRK1 protein expression. This data indicates that there are functional GIRK channels in breast cancer cells and that these channels are involved in cellular signaling. In the present research, to further define the signaling pathways involved, we performed RNA interference (siRNA studies. Three stealth siRNA constructs were made starting at bases 1104, 1315, and 1490 of the GIRK1 sequence. These constructs were transfected into MDA-MB-453 cells, and both RNA and protein were isolated. GIRK1, β2-adrenergic and 18S control levels were determined using real-time PCR 24 hours after transfection. All three constructs decreased GIRK1 mRNA levels. However, β2 mRNA levels were unchanged by the GIRK1 knockdown. GIRK1 protein levels were also reduced by the knockdown, and this knockdown led to decreases in beta-adrenergic, MAP kinase and Akt signaling.

  7. Propofol protects against high glucose-induced endothelial adhesion molecules expression in human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Zhu Minmin

    2013-01-01

    Full Text Available Abstract Background Hyperglycemia could induce oxidative stress, activate transcription factor nuclear factor kappa B (NF-κB, up-regulate expression of endothelial adhesion molecules, and lead to endothelial injury. Studies have indicated that propofol could attenuate oxidative stress and suppress NF-κB activation in some situations. In the present study, we examined whether and how propofol improved high glucose-induced up-regulation of endothelial adhesion molecules in human umbilical vein endothelial cells (HUVECs. Methods Protein expression of endothelial adhesion molecules, NF-κB, inhibitory subunit of NF-κBα (IκBα, protein kinase Cβ2 (PKCβ2, and phosphorylation of PKCβ2 (Ser660 were measured by Western blot. NF-κB activity was measured by electrophoretic mobility shift assay. PKC activity was measured with SignaTECT PKC assay system. Superoxide anion (O2.- accumulation was measured with the reduction of ferricytochrome c assay. Human peripheral mononuclear cells were prepared with Histopaque-1077 solution. Results High glucose induced the expression of endothelial selectin (E-selectin, intercellular adhesion molecule 1 (ICAM-1, vascular cell adhesion molecule 1 (VCAM-1, and increased mononuclear-endothelial adhesion. High glucose induced O2.- accumulation, PKCβ2 phosphorylation and PKC activation. Further, high glucose decreased IκBα expression in cytoplasm, increased the translocation of NF-κB from cytoplasm to nuclear, and induced NF-κB activation. Importantly, we found these high glucose-mediated effects were attenuated by propofol pretreatment. Moreover, CGP53353, a selective PKCβ2 inhibitor, decreased high glucose-induced NF-κB activation, adhesion molecules expression, and mononuclear-endothelial adhesion. Conclusion Propofol, via decreasing O2.- accumulation, down-regulating PKCβ2 Ser660 phosphorylation and PKC as well as NF-κB activity, attenuated high glucose-induced endothelial adhesion molecules expression

  8. Alterations in ovarian cancer cell adhesion drive taxol resistance by increasing microtubule dynamics in a FAK-dependent manner.

    Science.gov (United States)

    McGrail, Daniel J; Khambhati, Niti N; Qi, Mark X; Patel, Krishan S; Ravikumar, Nithin; Brandenburg, Chandler P; Dawson, Michelle R

    2015-04-17

    Chemorefractory ovarian cancer patients show extremely poor prognosis. Microtubule-stabilizing Taxol (paclitaxel) is a first-line treatment against ovarian cancer. Despite the close interplay between microtubules and cell adhesion, it remains unknown if chemoresistance alters the way cells adhere to their extracellular environment, a process critical for cancer metastasis. To investigate this, we isolated Taxol-resistant populations of OVCAR3 and SKOV3 ovarian cancer cell lines. Though Taxol-resistant cells neither effluxed more drug nor gained resistance to other chemotherapeutics, they did display increased microtubule dynamics. These changes in microtubule dynamics coincided with faster attachment rates and decreased adhesion strength, which correlated with increased surface β1-integrin expression and decreased focal adhesion formation, respectively. Adhesion strength correlated best with Taxol-sensitivity, and was found to be independent of microtubule polymerization but dependent on focal adhesion kinase (FAK), which was up-regulated in Taxol-resistant cells. FAK inhibition also decreased microtubule dynamics to equal levels in both populations, indicating alterations in adhesive signaling are up-stream of microtubule dynamics. Taken together, this work demonstrates that Taxol-resistance dramatically alters how ovarian cancer cells adhere to their extracellular environment causing down-stream increases in microtubule dynamics, providing a therapeutic target that may improve prognosis by not only recovering drug sensitivity, but also decreasing metastasis.

  9. Signaling transduction pathways involved in basophil adhesion and histamine release

    DEFF Research Database (Denmark)

    Sha, Quan; Poulsen, Lars K.; Gerwien, Jens

    2006-01-01

    Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles ...... of beta1 and beta2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase (PI3K), src-kinases and extracellular signal regulated kinase (ERK) 1/2 in basophil adhesion and histamine release (HR)....

  10. [Study on FAK regulation of migration of vascular endothelial cells depending upon focal adhesion proteins].

    Science.gov (United States)

    Gao, Min; Liu, Xiaoheng; Sun, Heng; Ren, Hongyi; Wang, Lijuan; Shen, Yang

    2013-06-01

    Tumor angiogenesis induced by vascular endothelial cells (VECs) migration is a necessary condition for tumor growth and metastasis. The purpose of this study is to investigate the effect of focal adhesion kinase (FAK) inhibitor (50nmol/mL) on the adhesion and migration of endothelial cells(ECs) and the expression of focal adhesion proteins vinculin, talin and paxillin. Scratch wound migration assay was performed to examine the effect of FAK inhibitor with 50nmol/mL on ECs migration at 0, 5, 10, 30, 60 and 120min, respectively. And immunofluorescence analysis was performed to detect the expression of F-actin in ECs treated with FAK inhibitor within 2h. Western blot was carried out to determine the effect of FAK inhibitor on expression of vinculin, talin and paxillin proteins. The results showed that the migration distance and the expression of F-actin in ECs treated with FAK inhibitor decreased significantly compared with that of the controls, and the level of vinculin showed no significant difference with increasing of treated time of FAK inhibitor. However, the talin and paxillin showed an identical decreasing tendency in 5-10min, but slowly going up in 30min and then after subsequently decreasing. The results of this study proved that blocking phosphorylation of FAK could inhibit VECs adhesion and migration by downregulating focal adhesion proteins so that it may inhibit tumor angiogenesis. This may provide a new approach for tumor therapy.

  11. UVB therapy decreases the adhesive interaction between peripheral blood mononuclear cells and dermal microvascular endothelium, and regulates the differential expression of CD54, VCAM-1, and E-selectin in psoriatic plaques

    Energy Technology Data Exchange (ETDEWEB)

    Cai, J.-P.; Harris, K.; Chin, Y.H. [Miami Univ., FL (United States). School of Medicine; Falanga, V.; Taylor, J.R. [Miami Univ., FL (United States). School of Medicine]|[Miami Veteran Affairs Medical Center, Miami, FL (United States)

    1996-01-01

    A dermal lymphocytic infiltrate is a characteristic feature of psoriasis, and may be involved in the pathogenesis of the disease. We have previously shown that specialized dermal microvascular endothelial cells (DMEC) in psoriatic lesions promote the selective adherence of the CD4 CD45Ro helper T-cell subset. In this study, we examined the adhesive interaction between peripheral blood mononuclear cells and psoriatic DMEC in patients treated with ultraviolet B light (UVB), and correlated the results with the expression and function of endothelial adhesion molecules on DMEC. (author).

  12. NCAM-mimetic, FGL peptide, restores disrupted fibroblast growth factor receptor (FGFR) phosphorylation and FGFR mediated signaling in neural cell adhesion molecule (NCAM)-deficient mice

    DEFF Research Database (Denmark)

    Aonurm-Helm, Anu; Berezin, Vladimir; Bock, Elisabeth;

    2010-01-01

    Neural cell adhesion molecule (NCAM) is a membrane-bound glycoprotein expressed on the surface of neuronal and glial cells. Previous in vitro studies have demonstrated that NCAM promotes neuronal functions largely via three main interaction partners: the fibroblast growth factor receptor (FGFR...... compared the levels of phosphorylation of FGFR1, Src kinase Fyn, Raf1 kinase, MAP kinases, Akt kinase and calcium/calmodulin-dependent kinases II and IV (CaMKII and CaMKIV) in the hippocampus of NCAM knockout mice to their wild-type littermates. The data of our study show that mice constitutively deficient...... in all isoforms of NCAM have decreased basal phosphorylation levels of FGFR1 and CaMKII and CaMKIV. Furthermore, NCAM-mimetic, FGL peptide, is found to be able to restore FGFR1, CaMKII and CaMKIV phosphorylation levels and thereby mimic the interactions of NCAM at this receptor in NCAM deficient mice...

  13. Combined glutamine and arginine decrease proinflammatory cytokine production by biopsies from Crohn's patients in association with changes in nuclear factor-kappaB and p38 mitogen-activated protein kinase pathways.

    Science.gov (United States)

    Lecleire, Stéphane; Hassan, Aktham; Marion-Letellier, Rachel; Antonietti, Michel; Savoye, Guillaume; Bôle-Feysot, Christine; Lerebours, Eric; Ducrotté, Philippe; Déchelotte, Pierre; Coëffier, Moïse

    2008-12-01

    Glutamine (Gln) and arginine (Arg) are conditionally essential amino acids with immunomodulatory properties. The aim of the study was to assess the effects of Gln and Arg alone or in combination on cytokine release by cultured colonic biopsies from patients with active Crohn's disease (CD). Ten consecutive patients [mean (range) age 26 (18-39) y] with active colonic CD (mean CD activity index: 383.7 +/- 129.8) were prospectively included in the study. Eight colonic biopsies were obtained via a colonoscopy and incubated during 18 h with low (physiological) or high (pharmacological) doses of Arg (0.1 or 2 mmol/L designated as Arg(low) or Arg(high), respectively) and Gln (0.6 or 10 mmol/L designated as Gln(low) or Gln(high), respectively). The concentrations of cytokines [interleukin (IL)-4, IL-10, IL-8, IL-6, tumor necrosis factor-alpha (TNFalpha), IL-1beta, interferon-gamma) were assessed by ELISA, and nitric oxide (NO) production was evaluated by Griess assay. Nuclear factor (NF)-kappaB p65 subunit, inhibitor of NFkappaB-alpha, and p38 mitogen-activated protein kinase (MAPK) were assessed by immunoblotting. Arg(high)/Gln(high) decreased the production of TNFalpha, IL-1beta, IL-8, and IL-6 (each P < 0.01). Arg(low)/Gln(high) decreased IL-6 and IL-8 production (both P < 0.01), whereas Arg(high)/Gln(low) did not affect cytokine and NO production. Arg(low)/Gln(high) and Arg(high)/Gln(high) decreased NF-kappaB p65 subunit expression, whereas p38 MAPK was decreased only by Arg(high)/Gln(high). Combined pharmacological doses of Arg and Gln decreased TNFalpha and the main proinflammatory cytokines release in active colonic CD biopsies via NF-kappaB and p38 MAPK pathways. These results could be the basis of prospective studies evaluating the effects of enteral supply of combined Arg and Gln during active CD.

  14. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion...... is the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental parameters......, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to significantly...

  15. Adhesive plasters

    Science.gov (United States)

    Holcombe, Jr., Cressie E.; Swain, Ronald L.; Banker, John G.; Edwards, Charlene C.

    1978-01-01

    Adhesive plaster compositions are provided by treating particles of Y.sub.2 O.sub.3, Eu.sub.2 O.sub.3, Gd.sub.2 O.sub.3 or Nd.sub.2 O.sub.3 with dilute acid solutions. The resulting compositions have been found to spontaneously harden into rigid reticulated masses resembling plaster of Paris. Upon heating, the hardened material is decomposed into the oxide, yet retains the reticulated rigid structure.

  16. Control of mesenchymal stem cell phenotype and differentiation depending on cell adhesion mechanism

    Directory of Open Access Journals (Sweden)

    J Kang

    2014-11-01

    Full Text Available Control of cell-matrix adhesion has become an important issue in the regulation of stem cell function. In this study, a maltose-binding protein (MBP-linked basic fibroblast growth factor (FGF2-immobilised polystyrene surface (PS-MBP-FGF2 was applied as an artificial matrix to regulate integrin-mediated signalling. We sought to characterise human mesenchymal-stem cell (hMSC behaviour in response to two different mechanisms of cell adhesion; (i FGF2-heparan sulphate proteoglycan (HSPG-mediated adhesion vs. (ii fibronectin (FN-integrin-mediated adhesion. Heparin inhibited hMSC adhesion to PS-MBP-FGF2 but not to FN-coated surface. The phosphorylation of focal adhesion kinase, cytoskeletal re-organisation, and cell proliferation were restricted in hMSCs adhering to PS-MBP-FGF2 compared to FN-coated surface. Expression of MSC markers, such as CD105, CD90 and CD166, decreased in hMSCs expanded on PS-MBP-FGF2 compared to expression in cells expanded on FN-coated surface. hMSCs that were expanded on FN-coated surface differentiated into osteogenic and adipogenic cells more readily than those that were expanded on PS-MBP-FGF2. Furthermore, we characterised the N-linked glycan structures of hMSCs depending on the cell adhesion mechanism using mass spectrometry (MS-based quantitative techniques. MS analysis revealed that 2,3-sialylated glycans, a potential marker of stem cell function, were more abundant on hMSCs expanded on FN-coated surface than on those expanded on PS-MBP-FGF2. Thus, the differentiation potential of hMSCs is controlled by the type of adhesion substrate that might provide an idea for the design of biomaterials to control stem cell fate. Elucidation of the glycan structure on the cell membrane may help characterise hMSC function.

  17. Control of mesenchymal stem cell phenotype and differentiation depending on cell adhesion mechanism.

    Science.gov (United States)

    Kang, J; Park, H M; Kim, Y W; Kim, Y H; Varghese, S; Seok, H K; Kim, Y G; Kim, S H

    2014-11-25

    Control of cell-matrix adhesion has become an important issue in the regulation of stem cell function. In this study, a maltose-binding protein (MBP)-linked basic fibroblast growth factor (FGF2)-immobilised polystyrene surface (PS-MBP-FGF2) was applied as an artificial matrix to regulate integrin-mediated signalling. We sought to characterise human mesenchymal-stem cell (hMSC) behaviour in response to two different mechanisms of cell adhesion; (i) FGF2-heparan sulphate proteoglycan (HSPG)-mediated adhesion vs. (ii) fibronectin (FN)-integrin-mediated adhesion. Heparin inhibited hMSC adhesion to PS-MBP-FGF2 but not to FN-coated surface. The phosphorylation of focal adhesion kinase, cytoskeletal re-organisation, and cell proliferation were restricted in hMSCs adhering to PS-MBP-FGF2 compared to FN-coated surface. Expression of MSC markers, such as CD105, CD90 and CD166, decreased in hMSCs expanded on PS-MBP-FGF2 compared to expression in cells expanded on FN-coated surface. hMSCs that were expanded on FN-coated surface differentiated into osteogenic and adipogenic cells more readily than those that were expanded on PS-MBP-FGF2. Furthermore, we characterised the N-linked glycan structures of hMSCs depending on the cell adhesion mechanism using mass spectrometry (MS)-based quantitative techniques. MS analysis revealed that 2,3-sialylated glycans, a potential marker of stem cell function, were more abundant on hMSCs expanded on FN-coated surface than on those expanded on PS-MBP-FGF2. Thus, the differentiation potential of hMSCs is controlled by the type of adhesion substrate that might provide an idea for the design of biomaterials to control stem cell fate. Elucidation of the glycan structure on the cell membrane may help characterise hMSC function.

  18. Focal adhesions and assessment of cytotoxicity

    NARCIS (Netherlands)

    van Kooten, TG; Klein, CL; Wagner, M; Kirkpatrick, CJ

    1999-01-01

    Focal adhesions are highly ordered assemblies of transmembrane receptors, extracellular matrix proteins, and a large number of cytoplasmic proteins, including structural proteins, as well as tyrosine kinases, phosphatases, and their substrates. They are now accepted as a prime component of signal tr

  19. Adhesion and cohesion.

    Science.gov (United States)

    von Fraunhofer, J Anthony

    2012-01-01

    The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  20. Adhesion and Cohesion

    Directory of Open Access Journals (Sweden)

    J. Anthony von Fraunhofer

    2012-01-01

    Full Text Available The phenomena of adhesion and cohesion are reviewed and discussed with particular reference to dentistry. This review considers the forces involved in cohesion and adhesion together with the mechanisms of adhesion and the underlying molecular processes involved in bonding of dissimilar materials. The forces involved in surface tension, surface wetting, chemical adhesion, dispersive adhesion, diffusive adhesion, and mechanical adhesion are reviewed in detail and examples relevant to adhesive dentistry and bonding are given. Substrate surface chemistry and its influence on adhesion, together with the properties of adhesive materials, are evaluated. The underlying mechanisms involved in adhesion failure are covered. The relevance of the adhesion zone and its importance with regard to adhesive dentistry and bonding to enamel and dentin is discussed.

  1. Cardiomyocyte apoptosis triggered by RAFTK/pyk2 via Src kinase is antagonized by paxillin.

    Science.gov (United States)

    Melendez, Jaime; Turner, Christopher; Avraham, Hava; Steinberg, Susan F; Schaefer, Erik; Sussman, Mark A

    2004-12-17

    Altered cellular adhesion and apoptotic signaling in cardiac remodeling requires coordinated regulation of multiple constituent proteins that comprise cytoskeletal focal adhesions. One such protein activated by cardiac remodeling is related adhesion focal tyrosine kinase (RAFTK, also known as pyk2). Adenoviral-mediated expression of RAFTK in neonatal rat cardiomyocytes involves concurrent increases in phosphorylation of Src, c-Jun N-terminal kinase, and p38 leading to characteristic apoptotic changes including cleavage of poly(ADP-ribose) polymerase, caspase-3 activation, and increased DNA laddering. DNA laddering was decreased by mutation of the Tyr(402) Src-binding site in RAFTK, suggesting a central role for Src activity in apoptotic cell death that was confirmed by adenoviral-mediated Src expression. Multiple apoptotic signaling cascades are recruited by RAFTK as demonstrated by prevention of apoptosis using caspase-3 inhibitor IV (caspase-3 specific inhibitor), PP2 (Src-specific kinase inhibitor), or Csk (cellular negative regulator for Src), as well as dominant negative constructs for p38beta or MKP-1. These RAFTK-mediated phenotypic characteristics are prevented by concurrent expression of wild-type or a phosphorylation-deficient paxillin mutated at Tyr(31) and Tyr(118). Wild-type or mutant paxillin protein accumulation in the cytoplasm has no overt effect upon cell structure, but paxillin accumulation prevents losses of myofibril organization as well as focal adhesion kinase, vinculin, and paxillin protein levels mediated by RAFTK. Apoptotic signaling cascade inhibition by paxillin indicates interruption of signaling proximal to but downstream of RAFTK activity. Chronic RAFTK activation in cardiac remodeling may represent a maladaptive reactive response that can be modulated by paxillin, opening up novel possibilities for inhibition of cardiomyocyte apoptosis and structural degeneration in heart failure.

  2. The Rheological Property of Potato Starch Adhesives

    Directory of Open Access Journals (Sweden)

    Junjun Liu

    2014-02-01

    Full Text Available The main goal of this study was to use potato starch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly potato starch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of potato starch adhesives decreased with the increasing of temperature; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared within potato starch adhesives which was pseudo-plastic fluids. Potato starch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  3. Advanced adhesives in electronics

    CERN Document Server

    Bailey, C

    2011-01-01

    Adhesives are widely used in the manufacture of electronic devices to act as passive and active components. Recently there has been considerable interest in the use of conductive adhesives. This book reviews key types of conductive adhesives, processing methods, properties and the way they can be modelled as well as potential applications.$bAdhesives for electronic applications serve important functional and structural purposes in electronic components and packaging, and have developed significantly over the last few decades. Advanced adhesives in electronics reviews recent developments in adhesive joining technology, processing and properties. The book opens with an introduction to adhesive joining technology for electronics. Part one goes on to cover different types of adhesive used in electronic systems, including thermally conductive adhesives, isotropic and anisotropic conductive adhesives and underfill adhesives for flip-chip applications. Part two focuses on the properties and processing of electronic ...

  4. Adhesion in microelectronics

    CERN Document Server

    Mittal, K L

    2014-01-01

    This comprehensive book will provide both fundamental and applied aspects of adhesion pertaining to microelectronics in a single and easily accessible source. Among the topics to be covered include; Various theories or mechanisms of adhesionSurface (physical or chemical) characterization of materials as it pertains to adhesionSurface cleaning as it pertains to adhesionWays to improve adhesionUnraveling of interfacial interactions using an array of pertinent techniquesCharacterization of interfaces / interphasesPolymer-polymer adhesionMetal-polymer adhesion  (metallized polymers)Polymer adhesi

  5. Decreased signaling competence as a result of receptor overexpression: overexpression of CD4 reduces its ability to activate p56lck tyrosine kinase and to regulate T-cell antigen receptor expression in immature CD4+CD8+ thymocytes.

    OpenAIRE

    Nakayama, T.; Wiest, D L; Abraham, K.M.; Munitz, T I; Perlmutter, R M; Singer, A

    1993-01-01

    Thymic selection of the developing T-cell repertoire occurs in immature CD4+CD8+ thymocytes, with the fate of individual thymocytes determined by the specificity of T-cell antigen receptor they express. However, T-cell antigen receptor expression in immature CD4+CD8+ thymocytes is actively down-regulated in CD4+CD8+ thymocytes by CD4-mediated tyrosine kinase signals that are generated in the thymus as a result of CD4 engagement by intrathymic ligands. In the present study we have examined the...

  6. Upregulation of paxillin and focal adhesion signaling follows Dystroglycan Complex deletions and promotes a hypertensive state of differentiation.

    Science.gov (United States)

    Sen, Shamik; Tewari, Manorama; Zajac, Allison; Barton, Elisabeth; Sweeney, H Lee; Discher, Dennis E

    2011-01-01

    Anchorage to matrix is mediated for many cells not only by integrin-based focal adhesions but also by a parallel assembly of integral and peripheral membrane proteins known as the Dystroglycan Complex. Deficiencies in either dystrophin (mdx mice) or γ-sarcoglycan (γSG(-/-) mice) components of the Dystroglycan Complex lead to upregulation of numerous focal adhesion proteins, and the phosphoprotein paxillin proves to be among the most prominent. In mdx muscle, paxillin-Y31 and Y118 are both hyper-phosphorylated as are key sites in focal adhesion kinase (FAK) and the stretch-stimulatable pro-survival MAPK pathway, whereas γSG(-/-) muscle exhibits more erratic hyper-phosphorylation. In cultured myotubes, cell tension generated by myosin-II appears required for localization of paxillin to adhesions while vinculin appears more stably integrated. Overexpression of wild-type (WT) paxillin has no obvious effect on focal adhesion density or the physical strength of adhesion, but WT and a Y118F mutant promote contractile sarcomere formation whereas a Y31F mutant shows no effect, implicating Y31 in striation. Self-peeling of cells as well as Atomic Force Microscopy (AFM) probing of cells with or without myosin-II inhibition indicate an increase in cell tension within paxillin-overexpressing cells. However, prednisolone, a first-line glucocorticoid for muscular dystrophies, decreases cell tension without affecting paxillin at adhesions, suggesting a non-linear relationship between paxillin and cell tension. Hypertension that results from upregulation of integrin adhesions is thus a natural and treatable outcome of Dystroglycan Complex down-regulation.

  7. Sesamin attenuates intercellular cell adhesion molecule-1 expression in vitro in TNF-alpha-treated human aortic endothelial cells and in vivo in apolipoprotein-E-deficient mice.

    Science.gov (United States)

    Wu, Wen-Huey; Wang, Shu-Huei; Kuan, I-I; Kao, Ya-Shi; Wu, Pei-Jhen; Liang, Chan-Jung; Chien, Hsiung-Fei; Kao, Chiu-Hua; Huang, Ching-Jang; Chen, Yuh-Lien

    2010-09-01

    Sesame lignans have antioxidative and anti-inflammatory properties. We focused on the effects of the lignans sesamin and sesamol on the expression of endothelial-leukocyte adhesion molecules in tumor necrosis factor-alpha (TNF-alpha)-treated human aortic endothelial cells (HAECs). When HAECs were pretreated with sesamin (10 or 100 microM), the TNF-alpha-induced expression of intercellular cell adhesion molecule-1 (ICAM-1) was significantly reduced (35 or 70% decrease, respectively) by Western blotting. Sesamol was less effective at inhibiting ICAM-1 expression (30% decrease at 100 microM). Sesamin and sesamol reduced the marked TNF-alpha-induced increase in human antigen R (HuR) translocation and the interaction between HuR and the 3'UTR of ICAM-1 mRNA. Both significantly reduced the binding of monocytes to TNF-alpha-stimulated HAECs. Sesamin significantly attenuated TNF-alpha-induced ICAM-1 expression and cell adhesion by downregulation of extracellular signal-regulated kinase 1/2 and p38. Furthermore, in vivo, sesamin attenuated intimal thickening and ICAM-1 expression seen in aortas of apolipoprotein-E-deficient mice. Taken together, these data suggest that sesamin inhibits TNF-alpha-induced extracellular signal-regulated kinase/p38 phosphorylation, nuclear translocation of NF-kappaB p65, cytoplasmic translocalization of HuR and thereby suppresses ICAM-1 expression, resulting in reduced adhesion of leukocytes. These results also suggest that sesamin may prevent the development of atherosclerosis and inflammatory responses.

  8. Hyaluronan synthase 3 (HAS3) overexpression downregulates MV3 melanoma cell proliferation, migration and adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Takabe, Piia, E-mail: piia.takabe@uef.fi [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland); Bart, Geneviève [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland); Ropponen, Antti [University of Eastern Finland, Institute of Clinical Medicine, 70211 Kuopio (Finland); Rilla, Kirsi; Tammi, Markku; Tammi, Raija; Pasonen-Seppänen, Sanna [University of Eastern Finland, Institute of Biomedicine, 70211 Kuopio (Finland)

    2015-09-10

    Malignant skin melanoma is one of the most deadly human cancers. Extracellular matrix (ECM) influences the growth of malignant tumors by modulating tumor cells adhesion and migration. Hyaluronan is an essential component of the ECM, and its amount is altered in many tumors, suggesting an important role for hyaluronan in tumorigenesis. Nonetheless its role in melanomagenesis is not understood. In this study we produced a MV3 melanoma cell line with inducible expression of the hyaluronan synthase 3 (HAS3) and studied its effect on the behavior of the melanoma cells. HAS3 overexpression expanded the cell surface hyaluronan coat and decreased melanoma cell adhesion, migration and proliferation by cell cycle arrest at G1/G0. Melanoma cell migration was restored by removal of cell surface hyaluronan by Streptomyces hyaluronidase and by receptor blocking with hyaluronan oligosaccharides, while the effect on cell proliferation was receptor independent. Overexpression of HAS3 decreased ERK1/2 phosphorylation suggesting that inhibition of MAP-kinase signaling was responsible for these suppressive effects on the malignant phenotype of MV3 melanoma cells. - Highlights: • Inducible HAS3-MV3 melanoma cell line was generated using Lentiviral transduction. • HAS3 overexpression inhibits MV3 cell migration via hyaluronan–receptor interaction. • HAS3 overexpression decreases MV3 melanoma cell proliferation and adhesion. • ERK1/2 phosphorylation is downregulated by 50% in HAS3 overexpressing cells. • The results suggest that hyaluronan has anti-cancer like effects in melanoma.

  9. Microtubule-dependent modulation of adhesion complex composition.

    Science.gov (United States)

    Ng, Daniel H J; Humphries, Jonathan D; Byron, Adam; Millon-Frémillon, Angélique; Humphries, Martin J

    2014-01-01

    The microtubule network regulates the turnover of integrin-containing adhesion complexes to stimulate cell migration. Disruption of the microtubule network results in an enlargement of adhesion complex size due to increased RhoA-stimulated actomyosin contractility, and inhibition of adhesion complex turnover; however, the microtubule-dependent changes in adhesion complex composition have not been studied in a global, unbiased manner. Here we used label-free quantitative mass spectrometry-based proteomics to determine adhesion complex changes that occur upon microtubule disruption with nocodazole. Nocodazole-treated cells displayed an increased abundance of the majority of known adhesion complex components, but no change in the levels of the fibronectin-binding α5β1 integrin. Immunofluorescence analyses confirmed these findings, but revealed a change in localisation of adhesion complex components. Specifically, in untreated cells, α5-integrin co-localised with vinculin at peripherally located focal adhesions and with tensin at centrally located fibrillar adhesions. In nocodazole-treated cells, however, α5-integrin was found in both peripherally located and centrally located adhesion complexes that contained both vinculin and tensin, suggesting a switch in the maturation state of adhesion complexes to favour focal adhesions. Moreover, the switch to focal adhesions was confirmed to be force-dependent as inhibition of cell contractility with the Rho-associated protein kinase inhibitor, Y-27632, prevented the nocodazole-induced conversion. These results highlight a complex interplay between the microtubule cytoskeleton, adhesion complex maturation state and intracellular contractile force, and provide a resource for future adhesion signaling studies. The proteomics data have been deposited in the ProteomeXchange with identifier PXD001183.

  10. Signaling transduction pathways involved in basophil adhesion and histamine release

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Background Little is known about basophil with respect to the different signaling transduction pathways involved in spontaneous, cytokine or anti-IgE induced adhesion and how this compares to IgE-dependent and IgE-independent mediator secretion. The purpose of the present study was to investigate the roles of β1 andβ2 integrins in basophil adhesion as well as hosphatidylinositol 3-kinase (PI3K), src-kinases and extracellular signal regulated kinase (ERK)1/2 in basophil adhesion and histamine release (HR). Methods Basophils (purity of 10%-50%) were preincubated with anti-CD29 or anti-CD18 blocking antibodies before used for adhesion study. Basophils were preincubated with the pharmacological inhibitors wortmannin, PP1, PD98059 before used for adhesion and HR study. Cell adherence to bovine serum albumin (BSA) or fibronectin (Fn) was monitored using cell associated histamine as a basophil marker and the histamine was measured by the glass fiber assay.Results Basophil spontaneous adhesion to Fn was inhibited by anti-CD29. Interleukin (IL)-3, granulocyte/macrophage colony stimulating factor (GM-CSF) induced adhesion to BSA was inhibited by anti-CD18. Wortmannin at 1 μmol/L and PP1 at 20 μmol/L strongly interfered with, whereas PD98059 at 50 μmol/L weakly inhibited basophil spontaneous adhesion to Fn. One μmol/L wortmannin strongly inhibited IL-3, IL-5, GM-CSF and anti-IgE induced adhesion to BSA. PP1 at 20 μmol/L partly inhibited anti-IgE induced adhesion. Fifty μmol/L PD98059 marginally inhibited IL-5, weakly inhibited anti-IgE, partly inhibited GM-CSF induced adhesion. Wortmannin, PP1 and PD98059 inhibited anti-IgE (1:100 or 1:1000) induced basophil HR in a dose dependent manner. They inhibited calcium ionophore A23187 (10 μmol/L, 5 μmol/L) induced basophil HR in a dose dependent manner, but to different extend with PP1 being the most efficient.Conclusions Basophil spontaneous adhesion to Fn is mediated by β1-integrins whereas cytokine induced adhesion

  11. Role of phosphoinositide 3-kinase/protein kinase B signal pathway in monocyte-endothelial adhesion induced by serum of rats with electrical burn%磷脂酰肌醇3激酶/蛋白激酶B通路在电烧伤大鼠血清诱导单核-内皮细胞黏附中的作用

    Institute of Scientific and Technical Information of China (English)

    阮琼芳; 赵超莉; 叶子青; 张卫东; 谢琼慧; 谢卫国

    2014-01-01

    24 h,THP-1细胞中磷酸化蛋白激酶B/Akt比值分别是正常血清组培养同时相点的2.66、3.69、1.17倍.(2)正常血清组、正常血清+阻断剂组、烧伤血清组、烧伤血清+阻断剂组培养3、6h,每100倍视野下黏附EA.hy926细胞的THP-1细胞数量分别为(231 ±45)、(280 ±47)、(703±169)、(335±85)个,(219±49)、(235±21)、(562±123)、(226±29)个,总体比较均差异明显(F值分别为25.630、18.975,P值均小于0.01).与正常血清组比较,烧伤血清组黏附EA.hy926细胞的THP-1细胞数在培养3、6h均明显增多(£值分别为6.189、6.601,P值均小于0.01);烧伤血清+阻断剂组黏附EA.hy926细胞的THP-1细胞数在培养3、6h较烧伤血清组均明显减少(t值分别为6.821、6.465,P值均小于0.01). 结论 电烧伤大鼠血清可诱导单核细胞分泌TNF-α,促进单核-内皮细胞黏附.而阻断PI3K/Akt信号通路,可有效抑制单核-内皮细胞的黏附.%Objective To observe the change in phosphoinositide 3-kinase/protein kinase B (PI3K/Akt) signal pathway in monocytes as induced by serum of rats with electrical burn,and to explore the effects of PI3K/Akt pathway on monocyte-endothelial cell adhesion.Methods Sixty-four SD rats of clean grade were inflicted with electrical burn for the collection of serum of rats with electrical burn ; another group of twenty-four SD rats were used to obtain normal serum without treatment.(1) Human monocyte line THP-1 was routinely cultured.The THP-1 cells in logarithmic phase were divided into normal serum group (resuspended in RPMI 1640 medium with 20% normal rat serum) and burn serum group (resuspended with RPMI 1640 medium with 20% serum of rats with electrical burn) according to the random number table,with 6 wells in each group.Morphology of THP-1 cells in normal serum group was observed at post culture hour (PCH) 24,and that in burn serum group at PCH 3,6,24.The contents of TNF-α in culture supernatant were determined by double

  12. Decreased Degradation of Internalized Follicle-Stimulating Hormone Caused by Mutation of Aspartic Acid 6.30550 in a Protein Kinase-CK2 Consensus Sequence in the Third Intracellular Loop of Human Follicle-Stimulating Hormone Receptor1

    Science.gov (United States)

    Kluetzman, Kerri S.; Thomas, Richard M.; Nechamen, Cheryl A.; Dias, James A.

    2011-01-01

    A naturally occurring mutation in follicle-stimulating hormone receptor (FSHR) gene has been reported: an amino acid change to glycine occurs at a conserved aspartic acid 550 (D550, D567, D6.30567). This residue is contained in a protein kinase-CK2 consensus site present in human FSHR (hFSHR) intracellular loop 3 (iL3). Because CK2 has been reported to play a role in trafficking of some receptors, the potential roles for CK2 and D550 in FSHR function were evaluated by generating a D550A mutation in the hFSHR. The hFSHR-D550A binds hormone similarly to WT-hFSHR when expressed in HEK293T cells. Western blot analyses showed lower levels of mature hFSHR-D550A. Maximal cAMP production of both hFSHR-D550A as well as the naturally occurring mutation hFSHR-D550G was diminished, but constitutive activity was not observed. Unexpectedly, when 125I-hFSH bound to hFSHR-D550A or hFSHR-D550G, intracellular accumulation of radiolabeled FSH was observed. Both sucrose and dominant-negative dynamin blocked internalization of radiolabeled FSH and its commensurate intracellular accumulation. Accumulation of radiolabeled FSH in cells transfected with hFSHR-D550A is due to a defect in degradation of hFSH as measured in pulse chase studies, and confocal microscopy imaging revealed that FSH accumulated in large intracellular structures. CK2 kinase activity is not required for proper degradation of internalized FSH because inhibition of CK2 kinase activity in cells expressing hFSHR did not uncouple degradation of internalized radiolabeled FSH. Additionally, the CK2 consensus site in FSHR iL3 is not required for binding because CK2alpha coimmunoprecipitated with hFSHR-D550A. Thus, mutation of D550 uncouples the link between internalization and degradation of hFSH. PMID:21270425

  13. Image analysis of blood platelets adhesion.

    Science.gov (United States)

    Krízová, P; Rysavá, J; Vanícková, M; Cieslar, P; Dyr, J E

    2003-01-01

    Adhesion of blood platelets is one of the major events in haemostatic and thrombotic processes. We studied adhesion of blood platelets on fibrinogen and fibrin dimer sorbed on solid support material (glass, polystyrene). Adhesion was carried on under static and dynamic conditions and measured as percentage of the surface covered with platelets. Within a range of platelet counts in normal and in thrombocytopenic blood we observed a very significant decrease in platelet adhesion on fibrin dimer with bounded active thrombin with decreasing platelet count. Our results show the imperative use of platelet poor blood preparations as control samples in experiments with thrombocytopenic blood. Experiments carried on adhesive surfaces sorbed on polystyrene showed lower relative inaccuracy than on glass. Markedly different behaviour of platelets adhered on the same adhesive surface, which differed only in support material (glass or polystyrene) suggest that adhesion and mainly spreading of platelets depends on physical quality of the surface. While on polystyrene there were no significant differences between fibrin dimer and fibrinogen, adhesion measured on glass support material markedly differed between fibrin dimer and fibrinogen. We compared two methods of thresholding in image analysis of adhered platelets. Results obtained by image analysis of spreaded platelets showed higher relative inaccuracy than results obtained by image analysis of platelets centres and aggregates.

  14. Economic Impact of the Use of an Absorbable Adhesion Barrier in Preventing Adhesions Following Open Gynecologic Surgeries.

    Science.gov (United States)

    Roy, Sanjoy; Carlton, Rashad; Weisberg, Martin; Clark, Ryan; Migliaccio-Walle, Kristen; Chapa, Hector

    2015-01-01

    We used an economic model to assess the impact of using the GYNECARE INTERCEED absorbable adhesion barrier for reducing the incidence of postoperative adhesions in open surgical gynecologic procedures. Caesarean section surgery, hysterectomy, myomectomy, ovarian surgery, tubal surgery, and endometriosis surgery were modeled with and without the use of GYNECARE INTERCEED absorbable adhesion barrier. Incremental GYNECARE INTERCEED absorbable adhesion barrier material costs, medical costs arising from complications, and adhesion-related readmissions were considered. GYNECARE INTERCEED absorbable adhesion barrier use was assumed in 75% of all procedures. The economic impact was reported during a 3-year period from a United States hospital perspective. Assuming 100 gynecologic surgeries of each type and an average of one GYNECARE INTERCEED absorbable adhesion barrier sheet per surgery, a net savings of $540,823 with GYNECARE INTERCEED absorbable adhesion barrier during 3 years is estimated. In addition, GYNECARE INTERCEED absorbable adhesion barrier use resulted in 62 fewer cases of patients developing adhesions. Although the use of GYNECARE INTERCEED absorbable adhesion barrier added $137,250 in material costs, this was completely offset by the reduction in length of stay ($178,766 savings), fewer adhesion-related readmissions ($458,220 savings), and operating room cost ($41,078 savings). Adoption of the GYNECARE INTERCEED absorbable adhesion barrier for appropriate gynecologic surgeries would likely result in significant savings for hospitals, driven primarily by clinical patient benefits in terms of decreased length of stay and adhesion-related readmissions.

  15. Microbial Degradation of Cellular Kinases Impairs Innate Immune Signaling and Paracrine TNFα Responses.

    Science.gov (United States)

    Barth, Kenneth; Genco, Caroline Attardo

    2016-10-04

    The NFκB and MAPK signaling pathways are critical components of innate immunity that orchestrate appropriate immune responses to control and eradicate pathogens. Their activation results in the induction of proinflammatory mediators, such as TNFα a potent bioactive molecule commonly secreted by recruited inflammatory cells, allowing for paracrine signaling at the site of an infection. In this study we identified a novel mechanism by which the opportunistic pathogen Porphyromonas gingivalis dampens innate immune responses by disruption of kinase signaling and degradation of inflammatory mediators. The intracellular immune kinases RIPK1, TAK1, and AKT were selectively degraded by the P. gingivalis lysine-specific gingipain (Kgp) in human endothelial cells, which correlated with dysregulated innate immune signaling. Kgp was also observed to attenuate endothelial responsiveness to TNFα, resulting in a reduction in signal flux through AKT, ERK and NFκB pathways, as well as a decrease in downstream proinflammatory mRNA induction of cytokines, chemokines and adhesion molecules. A deficiency in Kgp activity negated decreases to host cell kinase protein levels and responsiveness to TNFα. Given the essential role of kinase signaling in immune responses, these findings highlight a unique mechanism of pathogen-induced immune dysregulation through inhibition of cell activation, paracrine signaling, and dampened cellular proinflammatory responses.

  16. Casein kinases

    DEFF Research Database (Denmark)

    Issinger, O G

    1993-01-01

    subunits are highly conserved during evolution. The relationship between CK-2 alpha from humans and plants is still 73%. Similar relationships are reported for the beta-subunit. Chromosomal assignment of CK-2 alpha shows two gene loci, one of which is a pseudogene. They are located on different chromosomes......, no genetic changes are necessarily involved; the observed changes may be entirely due to a signal transduction pathway where CK-2 could be phosphorylated by another kinase(s). CK-2 cDNAs from various organisms have been isolated and characterized. From the deduced amino acid sequence it turns out that CK-2......-subunit affecting: (i) stability, (ii) enzyme specificity and (iii) enzyme activity. The question where CK-2 and its subunits are located throughout the cell cycle has also been addressed, mainly because of the large discrepancies that still exist between results obtained by different investigators. Tissue...

  17. PH dependent adhesive peptides

    Science.gov (United States)

    Tomich, John; Iwamoto, Takeo; Shen, Xinchun; Sun, Xiuzhi Susan

    2010-06-29

    A novel peptide adhesive motif is described that requires no receptor or cross-links to achieve maximal adhesive strength. Several peptides with different degrees of adhesive strength have been designed and synthesized using solid phase chemistries. All peptides contain a common hydrophobic core sequence flanked by positively or negatively charged amino acids sequences.

  18. Phosphatidylinositol 4-phosphate in the Golgi apparatus regulates cell-cell adhesion and invasive cell migration in human breast cancer.

    Science.gov (United States)

    Tokuda, Emi; Itoh, Toshiki; Hasegawa, Junya; Ijuin, Takeshi; Takeuchi, Yukiko; Irino, Yasuhiro; Fukumoto, Miki; Takenawa, Tadaomi

    2014-06-01

    Downregulation of cell-cell adhesion and upregulation of cell migration play critical roles in the conversion of benign tumors to aggressive invasive cancers. In this study, we show that changes in cell-cell adhesion and cancer cell migration/invasion capacity depend on the level of phosphatidylinositol 4-phosphate [PI(4)P] in the Golgi apparatus in breast cancer cells. Attenuating SAC1, a PI(4)P phosphatase localized in the Golgi apparatus, resulted in decreased cell-cell adhesion and increased cell migration in weakly invasive cells. In contrast, silencing phosphatidylinositol 4-kinase IIIβ, which generates PI(4)P in the Golgi apparatus, increased cell-cell adhesion and decreased invasion in highly invasive cells. Furthermore, a PI(4)P effector, Golgi phosphoprotein 3, was found to be involved in the generation of these phenotypes in a manner that depends on its PI(4)P-binding ability. Our results provide a new model for breast cancer cell progression in which progression is controlled by PI(4)P levels in the Golgi apparatus.

  19. Resveratrol and Estradiol Exert Disparate Effects on Cell Migration, Cell Surface Actin Structures, and Focal Adhesion Assembly in MDA-MB-231 Human Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Nicolas G. Azios

    2005-02-01

    Full Text Available Resveratrol, a grape polyphenol, is thought to be a cancer preventive, yet its effects on metastatic breast cancer are relatively unknown. Since cancer cell invasion is dependent on cell migration, the chemotactic response of MDA-MB-231 metastatic human breast cancer cells to resveratrol, estradiol (E2, or epidermal growth factor (EGF was investigated. Resveratrol decreased while E2 and EGF increased directed cell migration. Resveratrol may inhibit cell migration by altering the cytoskeleton. Resveratrol induced a rapid global array of filopodia and decreased focal adhesions and focal adhesion kinase (FAK activity. E2 or EGF treatment did not affect filopodia extension but increased lamellipodia and associated focal adhesions that are integral for cell migration. Combined resveratrol and E2 treatment resulted in a filopodia and focal adhesion response similar to resveratrol alone. Combined resveratrol and EGF resulted in a lamellipodia and focal adhesion response similar to EGF alone. E2 and to a lesser extent resveratrol increased EGFR activity. The cytoskeletal changes and EGFR activity in response to E2 were blocked by EGFR1 inhibitor indicating that E2 may increase cell migration via crosstalk with EGFR signaling. These data suggest a promotional role for E2 in breast cancer cell migration but an antiestrogenic, preventative role for resveratrol.

  20. Particle adhesion and removal

    CERN Document Server

    Mittal, K L

    2015-01-01

    The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal.  The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments.  Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand  particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and  n

  1. Understanding adhesive dentistry.

    Science.gov (United States)

    Burrow, Michael

    2010-03-01

    This review paper firstly provides an outline of the development of resin-based adhesives. A simple classification method is described based on whether an acid etching agent requiring a washing and drying step is used. These systems are called etch and rinse systems. The other adhesives that do not have the washing and drying steps are referred to as self-etching adhesives. The advantages and disadvantages of these groups of adhesives are discussed. Methods of adhering to the tooth surface are provided, especially where the resin-based adhesive reliability is difficult to control.

  2. IL-2 induces beta2-integrin adhesion via a wortmannin/LY294002-sensitive, rapamycin-resistant pathway. Phosphorylation of a 125-kilodalton protein correlates with induction of adhesion, but not mitogenesis

    DEFF Research Database (Denmark)

    Nielsen, M; Svejgaard, A; Skov, S;

    1996-01-01

    beta2-integrin-dependent, homotypic adhesion in Ag-specific, human T cell lines. The IL-2 adhesion response is blocked by wortmannin and LY294002, inhibitors of phosphatidylinositol-3 (PI-3) kinase activity. In contrast, rapamycin strongly inhibits IL-2-induced proliferation without inhibiting IL-2......, and cytochalasin E almost completely inhibit cytokine-induced tyrosine phosphorylation of p125, whereas tyrosine phosphorylation of PI-3 kinase, Janus kinases, Stat3, Stat5, and other proteins is unaffected. In contrast, rapamycin has little effect on IL-2-induced phosphorylation of p125. Taken together......, these data suggest that 1) IL-2R ligation induces homotypic adhesion through a wortmannin/LY294002-sensitive, rapamycin-resistant pathway, 2) tyrosine kinases play a critical role in cytokine-induced adhesion, and 3) adhesion, but not mitogenesis, correlates with enhanced tyrosine phosphorylation...

  3. Shear adhesion strength of aligned electrospun nanofibers.

    Science.gov (United States)

    Najem, Johnny F; Wong, Shing-Chung; Ji, Guang

    2014-09-01

    Inspiration from nature such as insects' foot hairs motivates scientists to fabricate nanoscale cylindrical solids that allow tens of millions of contact points per unit area with material substrates. In this paper, we present a simple yet robust method for fabricating directionally sensitive shear adhesive laminates. By using aligned electrospun nylon-6, we create dry adhesives, as a succession of our previous work on measuring adhesion energies between two single free-standing electrospun polymer fibers in cross-cylinder geometry, randomly oriented membranes and substrate, and peel forces between aligned fibers and substrate. The synthetic aligned cylindrical solids in this study are electrically insulating and show a maximal Mode II shear adhesion strength of 27 N/cm(2) on a glass slide. This measured value, for the purpose of comparison, is 270% of that reported from gecko feet. The Mode II shear adhesion strength, based on a commonly known "dead-weight" test, is 97-fold greater than the Mode I (normal) adhesion strength of the same. The data indicate a strong shear binding on and easy normal lifting off. Anisotropic adhesion (Mode II/Mode I) is pronounced. The size and surface boundary effects, crystallinity, and bending stiffness of fibers are used to understand these electrospun nanofibers, which vastly differ from otherwise known adhesive technologies. The anisotropic strength distribution is attributed to a decreasing fiber diameter and an optimized laminate thickness, which, in turn, influences the bending stiffness and solid-state "wettability" of points of contact between nanofibers and surface asperities.

  4. Adhesion in ceramics and magnetic media

    Science.gov (United States)

    Miyoshi, Kazuhisa

    1989-01-01

    When a ceramic is brought into contact with a metal or a polymeric material such as a magnetic medium, strong bonds form between the materials. For ceramic-to-metal contacts, adhesion and friction are strongly dependent on the ductility of the metals. Hardness of metals plays a much more important role in adhesion and friction than does the surface energy of metals. Adhesion, friction, surface energy, and hardness of a metal are all related to its Young's modulus and shear modulus, which have a marked dependence on the electron configuration of the metal. An increase in shear modulus results in a decrease in area of contact that is greater than the corresponding increase in surface energy (the fond energy) with shear modulus. Consequently, the adhesion and friction decrease with increasing shear modulus. For ceramics in contact with polymeric magnetic tapes, environment is extremely important. For example, a nitrogen environment reduces adhesion and friction when ferrite contacts polymeric tape, whereas a vacuum environment strengthens the ferrite-to-tape adhesion and increases friction. Adhesion and friction are strongly dependent on the particle loading of the tape. An increase in magnetic particle concentration increases the complex modulus of the tape, and a lower real area of contact and lower friction result.

  5. Inhibition of potentially anti-apoptotic proteins by antisense protein kinase C-alpha (Isis 3521) and antisense bcl-2 (G3139) phosphorothioate oligodeoxynucleotides: relationship to the decreased viability of T24 bladder and PC3 prostate cancer cells.

    Science.gov (United States)

    Benimetskaya, L; Miller, P; Benimetsky, S; Maciaszek, A; Guga, P; Beaucage, S L; Wilk, A; Grajkowski, A; Halperin, A L; Stein, C A

    2001-12-01

    Isis 3521 and G3139 are 20- and 18-mer phosphorothioate oligonucleotides, respectively, targeted to the protein kinase C (PKC)-alpha and bcl-2 mRNAs. Treatment of T24 bladder and PC3 prostate carcinoma cells with full-length and 3'-truncation mutants of Isis 3521 causes down-regulation of PKC-alpha protein and mRNA. However, at the level of a 15-mer and shorter, down-regulation of mRNA expression is no longer observed. Further, no diminution in cellular viability, as measured by 3-(4,5-dimethylthiazol-2-yl)2,5-diphenyl tetrazolium bromide assay, in response to increasing concentrations of paclitaxel, can be observed for these shorter oligomers. These observations not only indicate that PKC-alpha protein expression can be down-regulated by both RNase H-dependent and -independent mechanisms but also that down-regulation of PKC-alpha is insufficient by itself to "chemosensitize" cells. G3139, which down-regulates bcl-2 protein and mRNA expression, also down-regulates PKC-alpha protein and mRNA expression but not that of PKC-betaI, -epsilon, or -zeta. However, the down-regulation of PKC-alpha and bcl-2 are not linked. When the carrier Eufectin 5 is employed, only bcl-2 is down-regulated in both T24 and PC3 cells at 50 nM oligonucleotide concentration. At 100 nM, both bcl-2 and PKC-alpha expression are down-regulated, and only at this concentration can "chemosensitization" to paclitaxel and carboplatin be observed. In contrast, the down-regulation of bcl-2 seems to be linked with that of RelA (p65). However, this too is also not sufficient for chemosensitization, even though it leads to the loss of expression of genes under the putative control of nuclear factor-kappaB and to detachment of the cells from plastic surfaces. These results underscore the complexity of the intracellular requirements for the initiation of chemosensitization to anti-neoplastic agents.

  6. Syndecans promote integrin-mediated adhesion of mesenchymal cells in two distinct pathways

    DEFF Research Database (Denmark)

    Whiteford, James; Behrends, Volker; Kirby, Hishani;

    2007-01-01

    to form focal adhesions in response to fibronectin. Consistent with actin cytoskeleton organization, the process required Rho-GTP and Rho kinase. While syndecan-2 and -4 ectodomains could both promote integrin-mediated adhesion, their pathways were distinct, as shown by competition assays. Evidence...

  7. Regulation of Cell Adhesion Strength by Peripheral Focal Adhesion Distribution

    OpenAIRE

    2011-01-01

    Cell adhesion to extracellular matrices is a tightly regulated process that involves the complex interplay between biochemical and mechanical events at the cell-adhesive interface. Previous work established the spatiotemporal contributions of adhesive components to adhesion strength and identified a nonlinear dependence on cell spreading. This study was designed to investigate the regulation of cell-adhesion strength by the size and position of focal adhesions (FA). The cell-adhesive interfac...

  8. Gangliosides regulate tumor cell adhesion to collagen.

    Science.gov (United States)

    Kazarian, Tamara; Jabbar, Adnan A; Wen, Fei-Qui; Patel, Dharmesh A; Valentino, Leonard A

    2003-01-01

    The ability of tumor cells to adhere to extracellular matrix proteins is critical for migration and invasion. The factors that regulate tumor cell adhesion are poorly characterized. Gangliosides promote platelet adhesion and may also play a role in the adhesion of other cell types. We hypothesized that pharmacological depletion of membrane gangliosides from adherent cells would abrogate adhesion to collagen and promote migration and invasion. To test these hypotheses, LA-N1 neuroblastoma cells, which avidly adhere to collagen and are rich with membrane gangliosides (43.69 nmol/10(8) cells), were cultured in the presence of D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol-HCl. Endogenous gangliosides were reduced by 98% (0.76 nmol/10(8) cells) and adhesion to collagen decreased by 67%. There were no changes in cell morphology, viability, proliferation rate or apoptosis. Pre-incubation of ganglioside-depleted cells in conditioned medium from control cells restored adhesion to collagen (0.45 +/- 0.002), comparable to that of control cells (0.49 +/- 0.035). Similarly, pre-incubation of ganglioside-depleted cells with purified GD2 completely restored adhesion in a concentration-dependent manner. When LA-N1 cells were cultured with retinoic acid, a biological response modifier known to increase endogenous gangliosides, adhesion to collagen increased. Next, we questioned whether changes in adhesion would be reflected as changes in migration and invasion. Cells depleted of endogenous cellular gangliosides migrated more than control cells. Finally, control cells replete with their endogenous gangliosides demonstrated less invasive potential than control cells. The data demonstrate that endogenous tumor gangliosides increase neuroblastoma cell adhesion to collagen and reduce migration and invasion in vitro.

  9. Controllable and switchable capillary adhesion mechanism for bio-adhesive pads: Effect of micro patterns

    Institute of Scientific and Technical Information of China (English)

    ZHANG XiangJun; LIU Yuan; LIU YongHe; AHMED S.I.-U.

    2009-01-01

    Some insects and animals, such as bugs, grasshoppers and tree frogs, realize their efficient adhesion mechanism to glass surface, wall and ceiling by injecting a wetting liquid thin film into the pad-substrate contact area. Their ability to control adhesion (attaching or detaching from a surface) is in many cases connected to the contact geometry and surface patterns of their attachment pads. This paper focuses on the dependence of the capillary adhesion (wet adhesion) on the micro patterns of the bio-adhesive pads. The objective is to reveal the possible mechanism for a bio-adhesive pad to control capillary force through adjusting its micro-scale surface pattern and topography. A capillary adhesion force model is built up taking account of the combined role of micro-dimple geometry as well as the wetting behavior of the confined liquid thin film. Calculated results of the apparent contact angle on the regularly micro-dimpled surfaces are compared with and in good agreement with the experimental measurements. Simulation of the capillary adhesion force reveals that it is controllable in a large mag-nitude by adjusting a dimensionless surface pattern parameter k defined as a/(a+b), where a is the dia-meter of micro dimple, and (a+b) is the side length of one pattern cell. When adjusting the parameter k more than 0.75, the capillary adhesion force could be switchable from attractive to repulsive. This effect of micro patterns on the interfacial capillary force is proved to be dominant when the pad-substrate clearance decreases to the nano/micrometer scale. These results indicate that a controllable and switchable capillary adhesive mechanism might be utilized by a living insect or animal to realize its stable adhesion and quick releasing movement through adjusting the micro-pattern topography of its bio-adhesive pad.

  10. Electro-dry-adhesion.

    Science.gov (United States)

    Krahn, Jeffrey; Menon, Carlo

    2012-03-27

    This work presents novel conductive bioinspired dry adhesives with mushroom caps that enable the use of a synergistic combination of electrostatic and van der Waals forces (electro-dry-adhesion). An increase in shear adhesion bond strength of up to 2046% on a wide range of materials is measured when a maximum electrical field of 36.4 V μm(-1) is applied. A suction effect, due to the shape of the dry adhesive fibers, on overall adhesion was not noted for electro-dry-adhesives when testing was performed at both atmospheric and reduced pressure. Utilization of electrostatics to apply a preloading force to dry adhesive fiber arrays allows increased adhesion even after electrostatic force generation has been halted by ensuring the close contact necessary for van der Waals forces to be effective. A comparison is made between self-preloading of the electro-dry-adhesives and the direct application of a normal preloading pressure resulting in nearly the same shear bond strength with an applied voltage of 3.33 kV on the same sample.

  11. Reversible Thermoset Adhesives

    Science.gov (United States)

    Mac Murray, Benjamin C. (Inventor); Tong, Tat H. (Inventor); Hreha, Richard D. (Inventor)

    2016-01-01

    Embodiments of a reversible thermoset adhesive formed by incorporating thermally-reversible cross-linking units and a method for making the reversible thermoset adhesive are provided. One approach to formulating reversible thermoset adhesives includes incorporating dienes, such as furans, and dienophiles, such as maleimides, into a polymer network as reversible covalent cross-links using Diels Alder cross-link formation between the diene and dienophile. The chemical components may be selected based on their compatibility with adhesive chemistry as well as their ability to undergo controlled, reversible cross-linking chemistry.

  12. More automation, more adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Jens-Peter

    2012-07-01

    Although aluminium has become established as an absorber plate material, it is still seldom used for piping. Moreover, adhesive processes are becoming increasingly important in collector production. (orig.)

  13. Group I PAK inhibitor IPA-3 induces cell death and affects cell adhesivity to fibronectin in human hematopoietic cells.

    Directory of Open Access Journals (Sweden)

    Kateřina Kuželová

    Full Text Available P21-activated kinases (PAKs are involved in the regulation of multiple processes including cell proliferation, adhesion and migration. However, the current knowledge about their function is mainly based on results obtained in adherent cell types. We investigated the effect of group I PAK inhibition using the compound IPA-3 in a variety of human leukemic cell lines (JURL-MK1, MOLM-7, K562, CML-T1, HL-60, Karpas-299, Jurkat, HEL as well as in primary blood cells. IPA-3 induced cell death with EC50 ranging from 5 to more than 20 μM. Similar range was found for IPA-3-mediated dephosphorylation of a known PAK downstream effector, cofilin. The cell death was associated with caspase-3 activation, PARP cleavage and apoptotic DNA fragmentation. In parallel, 20 μM IPA-3 treatment induced rapid and marked decrease of the cell adhesivity to fibronectin. Per contra, partial reduction of PAK activity using lower dose IPA-3 or siRNA resulted in a slight increase in the cell adhesivity. The changes in the cell adhesivity were also studied using real-time microimpedance measurement and by interference reflection microscopy. Significant differences in the intracellular IPA-3 level among various cell lines were observed indicating that an active mechanism is involved in IPA-3 transport.

  14. Capillary adhesion forces between flexible fibers

    Science.gov (United States)

    Duprat, Camille; Protière, Suzie

    2016-11-01

    We consider the capillary adhesion produced by a drop placed between two elastic fibers. We measure the force exerted by the drop as we vary the inter-fiber distance, and report two types of wet adhesion: a weak capillary adhesion, where a liquid drop bridges the fibers, and a strong elastocapillary adhesion where the liquid is spread between two collapsed fibers. The weak adhesion is characterized by a force that increases linearly with the liquid length. With flexible fibers, the force exerted by the drop can induce deformation and rapid collapse, or zipping, of the fibers. This zipping results in a sudden increase of the wetted length and a force that departs from the linear evolution. As the inter-fiber distance is subsequently increased, the liquid length decreases while the fibers deformation increases, and the force actually reaches a plateau, i.e. remains constant until unzipping, or detachment of the fibers occurs. We measure the value of this plateau, i.e. the maximal adhesion force, as we vary the drop volume and the fibers elasticity. We also show that flexibility extends capillary adhesion to inter-fiber distances impossible to reach with rigid fibers, while keeping a constant pull-out force characteristic of the elastocapillary coupling.

  15. A new light on an old disease: adhesion signaling in pemphigus vulgaris.

    Science.gov (United States)

    Galichet, Arnaud; Borradori, Luca; Müller, Eliane J

    2014-01-01

    Disruption of desmosomal cadherin adhesion leads to the activation of intracellular signaling pathways that are responsible for blister formation in pemphigus vulgaris (PV). Recent studies corroborate the implication of the p38 mitogen-activated protein kinase in PV blistering via its downstream effector mitogen-activated protein kinase activated protein kinase 2. These insights highlight the key role of cadherins in tissue homeostasis and are expected to change pemphigus management.

  16. Attenuation of BPDE-induced p53 accumulation by TPA is associated with a decrease in stability and phosphorylation of p53 and down-regulation of NF-κB activation: Role of p38 MAP kinase

    Science.gov (United States)

    Mukherjee, Jagat J.; Sikka, Harish C.

    2005-01-01

    DNA damage caused by benzo[a]pyrene (BP) or other PAHs induce p53 protein as a protective measure to eliminate the possibility of mutagenic fixation of the DNA damage. 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibits p53 response induced by BP and other DNA-damaging agents and may cause tumor promotion. The molecular mechanism of attenuation of BP-induced p53 response by TPA is not known. We investigated the effect of TPA on p53 response in BPDE-treated mouse epidermal JB6(P+) Cl 41 cells. BPDE treatment induced p53 accumulation which was attenuated significantly by TPA. Cells treated with BPDE and TPA showed increased ratio of Mdm2 to p53 proteins in p53 immunoprecipitate and decreased p53 life span compared to BPDE-treated cells indicating p53 destabilization by TPA. TPA also inhibited BPDE-induced p53 phosphorylation at serine15. Activation of both ERKs and p38 MAPK by BPDE and attenuation of BPDE-induced p53 accumulation by U0126 or SB202190, specific inhibitor of MEK1/2 or p38 MAPK, indicate the role of ERKs and p38 MAPK in p53 accumulation. Interestingly, TPA potentiated BPDE-induced activation of ERKs whereas p38 MAPK activation was significantly inhibited by TPA, suggesting that inhibition of p38 MAPK is involved in p53 attenuation by TPA. Furthermore SB202190 treatment caused decreased p53 stability and inhibition of phosphorylation of p53 at serine 15 in BPDE-treated cells. We also observed that TPA or SB202190 attenuated BPDE-induced NF-κB activation in JB6 (Cl 41) cells harboring NF-κB reporter plasmid. To our knowledge this is the first report that TPA inhibits chemical carcinogen-induced NF-κB activation. Interference of TPA with BPDE-induced NF-κB activation implicates abrogation of p53 function which has been discussed. Overall our data suggest that abrogation of BPDE-induced p53 response and of NF-κB activation by TPA is mediated by impairment of signaling pathway involving p38 MAPK. PMID:16244358

  17. Angiogenin enhances cell migration by regulating stress fiber assembly and focal adhesion dynamics.

    Directory of Open Access Journals (Sweden)

    Saisai Wei

    Full Text Available Angiogenin (ANG acts on both vascular endothelial cells and cancer cells, but the underlying mechanism remains elusive. In this study, we carried out a co-immunoprecipitation assay in HeLa cells and identified 14 potential ANG-interacting proteins. Among these proteins, β-actin, α-actinin 4, and non-muscle myosin heavy chain 9 are stress fiber components and involved in cytoskeleton organization and movement, which prompted us to investigate the mechanism of action of ANG in cell migration. Upon confirmation of the interactions between ANG and the three proteins, further studies revealed that ANG co-localized with β-actin and α-actinin 4 at the leading edge of migrating cells. Down-regulation of ANG resulted in fewer but thicker stress fibers with less dynamics, which was associated with the enlargements of focal adhesions. The focal adhesion kinase activity and cell migration capacity were significantly decreased in ANG-deficient cells. Taken together, our data demonstrated that the existence of ANG in the cytoplasm optimizes stress fiber assembly and focal adhesion formation to accommodate cell migration. The finding that ANG promoted cancer cell migration might provide new clues for tumor metastasis research.

  18. MAP kinase pathways and calcitonin influence CD44 alternate isoform expression in prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Yang Kui

    2008-09-01

    Full Text Available Abstract Background Dysregulated expression and splicing of cell adhesion marker CD44 is found in many types of cancer. In prostate cancer (PC specifically, the standard isoform (CD44s has been found to be downregulated compared with benign tissue whereas predominant variant isoform CD44v7-10 is upregulated. Mitogen-activated protein kinase pathways and paracrine calcitonin are two common factors linked to dysregulated expression and splicing of CD44 in cancer. Calcitonin has been found to increase proliferation and invasion in PC acting through the protein kinase A pathway. Methods In androgen-independent PC with known high CD44v7-10 expression, CD44 total and CD44v7-10 RNA or protein were assessed in response to exogenous and endogenous calcitonin and to inhibitors of protein kinase A, MEK, JNK, or p38 kinase. Benign cells and calcitonin receptor-negative PC cells were also tested. Results MEK or p38 but not JNK reduced CD44 total RNA by 40%–65% in cancer and benign cells. Inhibition of protein kinase A reduced CD44 total and v7-10 protein expression. In calcitonin receptor-positive cells only, calcitonin increased CD44 variant RNA and protein by 3 h and persisting to 48 h, apparently dependent on an uninhibited p38 pathway. Cells with constitutive CT expression showed an increase in CD44v7-10 mRNA but a decrease in CD44 total RNA. Conclusion The MEK pathway increases CD44 RNA, while calcitonin, acting through the protein kinase A and p38 pathway, facilitates variant splicing. These findings could be used in the formulation of therapeutic methods for PC targeting CD44 alternate splicing.

  19. Preparation and Properties of Cornstarch Adhesives

    Directory of Open Access Journals (Sweden)

    Li Yang

    2013-08-01

    Full Text Available The main goal of this study was to use cornstarch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly cornstarch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of cornstarch adhesives increased and then decreased with the increasing of temperature and the maximum value was obtained at 10oC; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared wither cornstarch adhesives which was pseudo-plastic fluids. Cornstarch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  20. Neuroprotection of GluR5-containing kainate receptor activation against ischemic brain injury through decreasing tyrosine phosphorylation of N-methyl-D-aspartate receptors mediated by Src kinase.

    Science.gov (United States)

    Xu, Jie; Liu, Yong; Zhang, Guang-Yi

    2008-10-24

    Previous studies indicate that cerebral ischemia breaks the dynamic balance between excitatory and inhibitory inputs. The neural excitotoxicity induced by ionotropic glutamate receptors gain the upper hand during ischemia-reperfusion. In this paper, we investigate whether GluR5 (glutamate receptor 5)-containing kainate receptor activation could lead to a neuroprotective effect against ischemic brain injury and the related mechanism. The results showed that (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl) propanoic acid (ATPA), a selective GluR5 agonist, could suppress Src tyrosine phosphorylation and interactions among N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A), postsynaptic density protein 95 (PSD-95), and Src and then decrease NMDA receptor activation through attenuating tyrosine phosphorylation of NR2A and NR2B. More importantly, ATPA had a neuroprotective effect against ischemia-reperfusion-induced neuronal cell death in vivo. However, four separate drugs were found to abolish the effects of ATPA. These were selective GluR5 antagonist NS3763; GluR5 antisense oligodeoxynucleotides; CdCl(2), a broad spectrum blocker of voltage-gated calcium channels; and bicuculline, an antagonist of gamma-aminobutyric acid A (GABA(A)) receptor. GABA(A) receptor agonist muscimol could attenuate Src activation and interactions among NR2A, PSD-95 and Src, resulting the suppression of NMDA receptor tyrosine phosphorylation. Moreover, patch clamp recording proved that the activated GABA(A) receptor could inhibit NMDA receptor-mediated whole-cell currents. Taken together, the results suggest that during ischemia-reperfusion, activated GluR5 may facilitate Ca(2+)-dependent GABA release from interneurons. The released GABA can activate postsynaptic GABA(A) receptors, which then attenuates NMDA receptor tyrosine phosphorylation through inhibiting Src activation and disassembling the signaling module NR2A-PSD-95-Src. The final result of this process is that the pyramidal

  1. Study on the Rheological Property of Cassava Starch Adhesives

    Directory of Open Access Journals (Sweden)

    Junjun Liu

    2014-03-01

    Full Text Available The main goal of this study was to use cassava starch in the production of environmentally sound adhesives. ‘Three-formaldehyde glue’ pollutes the environment and harms to human health strongly, which widely used for wood-based panels preparation. Environment-friendly cassava starch adhesives were prepared using method of oxidation-gelatinization, insteading of the three formaldehyde glue. The effects of the quality ratio of starch and water, temperature and shear rate on the apparent viscosity of the adhesive were studied. The rheological eigenvalue of apparent viscosity was studied through nonlinear regression. The results showed that the apparent viscosity of cassava starch adhesives decreased with the increasing of temperature; the apparent viscosity decreased slowly with the increasing of rotor speed; the phenomenon of shear thinning appeared within cassava starch adhesives which was pseudo-plastic fluids. Cassava starch adhesives with characteristics of non-toxic, no smell and pollution could be applied in interior and upscale packaging.

  2. Prevention of bacterial adhesion

    DEFF Research Database (Denmark)

    Klemm, Per; Vejborg, Rebecca Munk; Hancock, Viktoria

    2010-01-01

    Management of bacterial infections is becoming increasingly difficult due to the emergence and increasing prevalence of bacterial pathogens that are resistant to available antibiotics. Conventional antibiotics generally kill bacteria by interfering with vital cellular functions, an approach...... that imposes selection pressure for resistant bacteria. New approaches are urgently needed. Targeting bacterial virulence functions directly is an attractive alternative. An obvious target is bacterial adhesion. Bacterial adhesion to surfaces is the first step in colonization, invasion, and biofilm formation....... As such, adhesion represents the Achilles heel of crucial pathogenic functions. It follows that interference with adhesion can reduce bacterial virulence. Here, we illustrate this important topic with examples of techniques being developed that can inhibit bacterial adhesion. Some of these will become...

  3. Tissue adhesives in otorhinolaryngology

    Directory of Open Access Journals (Sweden)

    Schneider, Gerlind

    2009-01-01

    Full Text Available The development of medical tissue adhesives has a long history without finding an all-purpose tissue adhesive for clinical daily routine. This is caused by the specific demands which are made on a tissue adhesive, and the different areas of application. In otorhinolaryngology, on the one hand, this is the mucosal environment as well as the application on bones, cartilage and periphery nerves. On the other hand, there are stressed regions (skin, oral cavity, pharynx, oesophagus, trachea and unstressed regions (middle ear, nose and paranasal sinuses, cranial bones. But due to the facts that adhesives can have considerable advantages in assuring surgery results, prevention of complications and so reduction of medical costs/treatment expenses, the search for new adhesives for use in otorhinolaryngology will be continued intensively. In parallel, appropriate application systems have to be developed for microscopic and endoscopic use.

  4. Hyperoxia increases the elastic modulus of alveolar epithelial cells through Rho kinase.

    Science.gov (United States)

    Wilhelm, Kristina R; Roan, Esra; Ghosh, Manik C; Parthasarathi, Kaushik; Waters, Christopher M

    2014-02-01

    Patients with acute lung injury are administered high concentrations of oxygen during mechanical ventilation, and while both hyperoxia and mechanical ventilation are necessary, each can independently cause additional injury. However, the precise mechanisms that lead to injury are not well understood. We hypothesized that alveolar epithelial cells may be more susceptible to injury caused by mechanical ventilation because hyperoxia causes cells to be stiffer due to increased filamentous actin (f-actin) formation via the GTPase RhoA and its effecter Rho kinase (ROCK). We examined cytoskeletal structures in cultured murine lung alveolar epithelial cells (MLE-12) under normoxic and hyperoxic (48 h) conditions. We also measured cell elasticity (E) using an atomic force microscope in the indenter mode. Hyperoxia caused increased f-actin stress fibers and bundle formation, an increase in g- and f-actin, an increase in nuclear area and a decrease in nuclear height, and cells became stiffer (higher E). Treatment with an inhibitor (Y-27632) of ROCK significantly decreased E and prevented the cytoskeletal changes, while it did not influence the nuclear height and area. Pre-exposure of cells to hyperoxia promoted detachment when cells were subsequently stretched cyclically, but the ROCK inhibitor prevented this effect. Hyperoxia caused thickening of vinculin focal adhesion plaques, and inhibition of ROCK reduced the formation of distinct focal adhesion plaques. Phosphorylation of focal adhesion kinase was significantly reduced by both hyperoxia and treatment with Y-27632. Hyperoxia caused increased cell stiffness and promoted cell detachment during stretch. These effects were ameliorated by inhibition of ROCK.

  5. Ganoderiol A-enriched extract suppresses migration and adhesion of MDA-MB-231 cells by inhibiting FAK-SRC-paxillin cascade pathway.

    Directory of Open Access Journals (Sweden)

    Guo-Sheng Wu

    Full Text Available Cell adhesion, migration and invasion are critical steps for carcinogenesis and cancer metastasis. Ganoderma lucidum, also called Lingzhi in China, is a traditional Chinese medicine, which exhibits anti-proliferation, anti-inflammation and anti-metastasis properties. Herein, GAEE, G. lucidum extract mainly contains ganoderiol A (GA, dihydrogenated GA and GA isomer, was shown to inhibit the abilities of adhesion and migration, while have a slight influence on that of invasion in highly metastatic breast cancer MDA-MB-231 cells at non-toxic doses. Further investigation revealed that GAEE decreased the active forms of focal adhesion kinase (FAK and disrupted the interaction between FAK and SRC, which lead to deactivating of paxillin. Moreover, GAEE treatment downregulated the expressions of RhoA, Rac1, and Cdc42, and decreased the interaction between neural Wiskott-Aldrich Syndrome protein (N-WASP and Cdc42, which impair cell migration and actin assembly. To our knowledge, this is the first report to show that G.lucidum triterpenoids could suppress cell migration and adhesion through FAK-SRC-paxillin signaling pathway. Our study also suggests that GAEE may be a potential agent for treatment of breast cancer.

  6. Platelet Adhesion to Podoplanin Under Flow is Mediated by the Receptor CLEC-2 and Stabilised by Src/Syk-Dependent Platelet Signalling

    Science.gov (United States)

    Pollitt, Alice Y.; Lowe, Kate; Latif, Arusa; Nash, Gerard B.

    2015-01-01

    Summary Platelet-specific deletion of CLEC-2, which signals through Src and Syk kinases, or global deletion of its ligand podoplanin results in blood-filled lymphatics during mouse development. Platelet-specific Syk deficiency phenocopies this defect, indicating that platelet activation is required for lymphatic development. In the present study, we investigated whether CLEC-2-podoplanin interactions could support platelet arrest from blood flow and whether platelet signalling is required for stable platelet adhesion to lymphatic endothelial cells (LECs) and recombinant podoplanin under flow. Perfusion of human or mouse blood over human LEC monolayers led to platelet adhesion and aggregation. Following αIIbβ3 blockade, individual platelets still adhered. Platelet binding occurred at venous but not arterial shear rates. There was no adhesion using CLEC-2-deficient blood or to vascular endothelial cells (which lack podoplanin). Perfusion of human blood over human Fc-podoplanin (hFcPDPN) in the presence of monoclonal antibody IV.3 to block FcγRIIA receptors led to platelet arrest at similar shear rates to those used on LECs. Src and Syk inhibitors significantly reduced global adhesion of human or mouse platelets to LECs and hFcPDPN. A similar result was seen using Syk-deficient mouse platelets. Reduced platelet adhesion was due to a decrease in the stability of binding. In conclusion, our data reveal that CLEC-2 is an adhesive receptor that supports platelet arrest to podoplanin under venous shear. Src/Syk-dependent signalling stabilises platelet adhesion to podoplanin, providing a possible molecular mechanism contributing to the lymphatic defects of Syk-deficient mice. PMID:25694214

  7. Improving adhesion of seasonings to crackers with hydrocolloid solutions.

    Science.gov (United States)

    Armstrong, Matthew E; Barringer, Sheryl A

    2013-11-01

    Food powders were applied on crackers that had been coated using water, oil, emulsion, sucrose, or hydrocolloid solutions. The hydrocolloids that were used include gellan gum, kappa-carrageenan, methylcellulose, gum karaya, gum tragacanth, gum arabic, guar gum, modified starch, and maltodextrin. Solutions of similar hydrophobicity to the powder gave the greatest adhesion. NaCl, barbecue (BBQ), ranch, and sour cream & onion (SC&O) seasoning showed greatest adhesion with water, cheese powder with an emulsion of 12.5% to 25% oil, and cocoa powder with oil. For NaCl, BBQ, ranch, and SC&O seasoning, hydrocolloids improved the adhesion over using water alone, with gellan gum providing the greatest adhesion. Hydrocolloid structural differences, including the presence or absence of branching, substitution of sugar units, and molecular weight affect water binding and thickening of the hydrocolloid spray that seemed to be significant factors affecting adhesion of powders to the target surface. For cheese powder, hydrocolloids were capable of replacing the oil within an emulsion while improving or maintaining the same level of adhesion, with gum arabic providing the greatest adhesion. For cocoa powder, hydrocolloid solutions were ineffective adhesives due to differences in hydrophilicity that result in insolubility. The effect of hydrocolloid concentration on adhesion was dependent both on the hydrocolloid type and the concentration that is sprayable, with 0.5% being the optimum concentration for most gums. Adhesion using sucrose solutions was determined by particle size and relative hydrophobicity. Increasing sucrose concentration decreased adhesion of smaller particles, but increased adhesion of larger particles. Adhesion of NaCl significantly increased with decreasing NaCl size using oil, water, and sucrose solutions.

  8. [Endothelial cell adhesion molecules].

    Science.gov (United States)

    Ivanov, A N; Norkin, I A; Puchin'ian, D M; Shirokov, V Iu; Zhdanova, O Iu

    2014-01-01

    The review presents current data concerning the functional role of endothelial cell adhesion molecules belonging to different structural families: integrins, selectins, cadherins, and the immunoglobulin super-family. In this manuscript the regulatory mechanisms and factors of adhesion molecules expression and distribution on the surface of endothelial cells are discussed. The data presented reveal the importance of adhesion molecules in the regulation of structural and functional state of endothelial cells in normal conditions and in pathology. Particular attention is paid to the importance of these molecules in the processes of physiological and pathological angiogenesis, regulation of permeability of the endothelial barrier and cell transmigration.

  9. Lactobacillus Adhesion to Mucus

    Directory of Open Access Journals (Sweden)

    Maxwell L. Van Tassell

    2011-05-01

    Full Text Available Mucus provides protective functions in the gastrointestinal tract and plays an important role in the adhesion of microorganisms to host surfaces. Mucin glycoproteins polymerize, forming a framework to which certain microbial populations can adhere, including probiotic Lactobacillus species. Numerous mechanisms for adhesion to mucus have been discovered in lactobacilli, including partially characterized mucus binding proteins. These mechanisms vary in importance with the in vitro models studied, which could significantly affect the perceived probiotic potential of the organisms. Understanding the nature of mucus-microbe interactions could be the key to elucidating the mechanisms of probiotic adhesion within the host.

  10. Bioinspired pressure actuated adhesive system

    NARCIS (Netherlands)

    Paretkar, D.R.; Kamperman, M.M.G.; Schneider, A.S.; Martina, D.; Creton, C.; Arzt, E.

    2011-01-01

    We developed a dry synthetic adhesive system inspired by gecko feet adhesion that can switch reversibly from adhesion to non-adhesion with applied pressure as external stimulus. Micropatterned polydimethylsiloxane (PDMS) surfaces with pillars of 30 µm length and 10 µm diameter were fabricated using

  11. Rho-kinase inhibition in the therapy of cardiovascular disease.

    Science.gov (United States)

    Lai, Andrew; Frishman, William H

    2005-01-01

    Rho is a GTPase known to be a major mediator in the formation of stress fibers and focal adhesions, cell morphology, and smooth muscle contraction. Its role in smooth muscle contraction has led to exploration into the connection between Rho-mediated kinase activity and cardiovascular disease. The role of Rho-kinase in calcium sensitization for vascular smooth muscle contraction has recently been characterized. Inappropriate coronary artery vasoconstriction resulting from increased Rho-kinase in the vascular system is likely involved in the pathogenesis of exercise-induced myocardial ischemia, spontaneous coronary artery spasm, and hypertension. In clinical trials, Rho-kinase inhibitors such as fasudil and Y-27632 have demonstrated antiischemic, antivasospastic, and antihypertensive effects. These compounds have also exhibited the ability to blunt progression of cardiomyocyte hypertrophy and cardiac remodeling in heart failure. As such, Rho-kinase inhibition represents a potential novel therapeutic approach in cardiovascular disease.

  12. Immunotherapeutic modulation of intraperitoneal adhesions by Asparagus racemosus.

    Directory of Open Access Journals (Sweden)

    Rege N

    1989-10-01

    Full Text Available The hypothesis that macrophages appear to play a pivotal role in the development of intraperitoneal adhesions and that modulation of macrophage activity, therefore, is likely to provide a tool for prevention of adhesions, was tested in the present study. Effect of Asparagus racemosus, an indigenous agent with immunostimulant properties, was evaluated in an animal model of intraperitoneal adhesions induced by caecal rubbing. Animals were sacrificed 15 days following surgery. The peritoneal macrophages were collected to assess their activity. At the same time, peritoneal cavity was examined for the presence of adhesions, which were graded. A significant decrease was observed in the adhesion scores attained by animals receiving Asparagus racemosus. This was associated with significant increase in the activity of macrophages (70.1 +/- 2.52, compared to that in surgical controls (53.77 +/- 10.8. These findings support our hypothesis and provide a novel approach for the prevention and management of post-operative adhesions.

  13. FAK Inhibition Decreases Hepatoblastoma Survival Both In Vitro and In Vivo12

    Science.gov (United States)

    Gillory, Lauren A; Stewart, Jerry E; Megison, Michael L; Nabers, Hugh C; Mroczek-Musulman, Elizabeth; Beierle, Elizabeth A

    2013-01-01

    Hepatoblastoma is the most frequently diagnosed liver tumor of childhood, and children with advanced, metastatic or relapsed disease have a disease-free survival rate under 50%. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumor development and progression. FAK has been found in other pediatric solid tumors and in adult hepatocellular carcinoma, leading us to hypothesize that FAK would be present in hepatoblastoma and would impact its cellular survival. In the current study, we showed that FAK was present and phosphorylated in human hepatoblastoma tumor specimens. We also examined the effects of FAK inhibition upon hepatoblastoma cells using a number of parallel approaches to block FAK including RNAi and small molecule FAK inhibitors. FAK inhibition resulted in decreased cellular survival, invasion, and migration and increased apoptosis. Further, small molecule inhibition of FAK led to decreased tumor growth in a nude mouse xenograft model of hepatoblastoma. The findings from this study will help to further our understanding of the regulation of hepatoblastoma tumorigenesis and may provide desperately needed novel therapeutic strategies and targets for aggressive, recurrent, or metastatic hepatoblastomas. PMID:23544173

  14. Underwater Adhesives Retrofit Pipelines with Advanced Sensors

    Science.gov (United States)

    2015-01-01

    Houston-based Astro Technology Inc. used a partnership with Johnson Space Center to pioneer an advanced fiber-optic monitoring system for offshore oil pipelines. The company's underwater adhesives allow it to retrofit older deepwater systems in order to measure pressure, temperature, strain, and flow properties, giving energy companies crucial data in real time and significantly decreasing the risk of a catastrophe.

  15. Dry adhesives with sensing features

    Science.gov (United States)

    Krahn, J.; Menon, C.

    2013-08-01

    Geckos are capable of detecting detachment of their feet. Inspired by this basic observation, a novel functional dry adhesive is proposed, which can be used to measure the instantaneous forces and torques acting on an adhesive pad. Such a novel sensing dry adhesive could potentially be used by climbing robots to quickly realize and respond appropriately to catastrophic detachment conditions. The proposed torque and force sensing dry adhesive was fabricated by mixing Carbon Black (CB) and Polydimethylsiloxane (PDMS) to form a functionalized adhesive with mushroom caps. The addition of CB to PDMS resulted in conductive PDMS which, when under compression, tension or torque, resulted in a change in the resistance across the adhesive patch terminals. The proposed design of the functionalized dry adhesive enables distinguishing an applied torque from a compressive force in a single adhesive pad. A model based on beam theory was used to predict the change in resistance across the terminals as either a torque or compressive force was applied to the adhesive patch. Under a compressive force, the sensing dry adhesive was capable of measuring compression stresses from 0.11 Pa to 20.9 kPa. The torque measured by the adhesive patch ranged from 2.6 to 10 mN m, at which point the dry adhesives became detached. The adhesive strength was 1.75 kPa under an applied preload of 1.65 kPa for an adhesive patch with an adhesive contact area of 7.07 cm2.

  16. Dynamin forms a Src kinase-sensitive complex with Cbl and regulates podosomes and osteoclast activity.

    Science.gov (United States)

    Bruzzaniti, Angela; Neff, Lynn; Sanjay, Archana; Horne, William C; De Camilli, Pietro; Baron, Roland

    2005-07-01

    Podosomes are highly dynamic actin-containing adhesion structures found in osteoclasts, macrophages, and Rous sarcoma virus (RSV)-transformed fibroblasts. After integrin engagement, Pyk2 recruits Src and the adaptor protein Cbl, forming a molecular signaling complex that is critical for cell migration, and deletion of any molecule in this complex disrupts podosome ring formation and/or decreases osteoclast migration. Dynamin, a GTPase essential for endocytosis, is also involved in actin cytoskeleton remodeling and is localized to podosomes where it has a role in actin turnover. We found that dynamin colocalizes with Cbl in the actin-rich podosome belt of osteoclasts and that dynamin forms a complex with Cbl in osteoclasts and when overexpressed in 293VnR or SYF cells. The association of dynamin with Cbl in osteoclasts was decreased by Src tyrosine kinase activity and we found that destabilization of the dynamin-Cbl complex involves the recruitment of Src through the proline-rich domain of Cbl. Overexpression of dynamin increased osteoclast bone resorbing activity and migration, whereas overexpression of dynK44A decreased osteoclast resorption and migration. These studies suggest that dynamin, Cbl, and Src coordinately participate in signaling complexes that are important in the assembly and remodeling of the actin cytoskeleton, leading to changes in osteoclast adhesion, migration, and resorption.

  17. Coatings against corrosion and microbial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Telegdi, J.; Szabo, T.; Al-Taher, F.; Pfeifer, E.; Kuzmann, E.; Vertes, A. [Chemical Research Center, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59/67 (Hungary)

    2010-12-15

    A systematic study on anti-corrosion and anti-fouling effect of hydrophobic Langmuir-Blodgett and self-assembled molecular layers deposited on metal surfaces, as well as anti-microbial adhesion properties of coatings with biocide is presented. Both types of efficiencies produced by LB films are enhanced by Fe{sup 3+} ions built in the molecular film. The quaternary ammonium type biocide embedded into the cross-linked gelatin decreased significantly the microbial adhesion, the biofilm formation. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Asymmetric Tyrosine Kinase Arrangements in Activation or Autophosphorylation of Receptor Tyrosine Kinases

    Energy Technology Data Exchange (ETDEWEB)

    J Bae; J Schlessinger

    2011-12-31

    Receptor tyrosine kinases (RTKs) play important roles in the control of many cellular processes including cell proliferation, cell adhesion, angiogenesis, and apoptosis. Ligand-induced dimerization of RTKs leads to autophosphorylation and activation of RTKs. Structural studies have shown that while isolated ectodomains of several RTKs form symmetric dimers the isolated cytoplasmic kinase domains of epidermal growth factor receptor (EGFR) and fibroblast growth factor receptor (FGFR) form asymmetric dimers during their activation. Binding of one kinase molecule of EGFR to a second kinase molecule asymmetrically leads to stimulation of kinase activity and enhanced autophosphorylation. Furthermore, the structures of the kinase domain of FGFR1 and FGFR2 reveal the formation of asymmetric interfaces in the processes of autophosphorylation at their specific phosphotyrosine (pY) sites. Disruption of asymmetric dimer interface of EGFR leads to reduction in enzymatic activity and drastic reduction of autophosphorylation of FGFRs in ligandstimulated live cells. These studies demonstrate that asymmetric dimer formation is as a common phenomenon critical for activation and autophosphorylation of RTKs.

  19. The effect of acrylic latex-based polymer on cow blood adhesive resins for wood composites

    Science.gov (United States)

    Yan, J.; Lin, H. L.; Feng, G. Z.; Gunasekaran, S.

    2016-07-01

    In this paper, alkali-modified cow blood adhesive (BA) and blood adhesive/acrylic latex-based adhesive (BA/ALB) were prepared. The physicochemical and adhesion properties of cow blood adhesive such as UV- visible spectra, particle size, viscosity were evaluated; share strength, water resistance were tested. UV- visible spectra indicates that the strong bonding strength of BA/ALB appeared after incorporating; the particle size of adhesive decreased with the increase of ALB concentration, by mixing ALB and BA, hydrophilic polymer tends locate or extand the protein chains and provide stability of the particles; viscosity decreased as shear rate increased in concordance with a pseudoplastic behavior; both at dry and soak conditions, BA and ALB/BA show significant difference changes when mass fraction of ALB in blend adhesive was over 30% (p latex-based adhesive significantly increased the strength and water resistance of the resulting wood.

  20. Pharmacological blockade of FAK autophosphorylation decreases human glioblastoma tumor growth and synergizes with temozolomide

    Science.gov (United States)

    Golubovskaya, Vita M.; Huang, Grace; Ho, Baotran; Yemma, Michael; Morrison, Carl D.; Lee, Jisook; Eliceiri, Brian P.; Cance, William G.

    2012-01-01

    Malignant gliomas are characterized by aggressive tumor growth with a mean survival of 15–18 months and frequently developed resistance to temozolomide. Therefore, strategies that sensitize glioma cells to temozolomide have a high translational impact. We have studied focal adhesion kinase (FAK), a tyrosine kinase and emerging therapeutic target that is known to be highly expressed and activated in glioma. In this report we tested the FAK autophosphorylation inhibitor, Y15 in DBTRG and U87 glioblastoma cells. Y15 significantly decreased viability and clonogenicity in a dose-dependent manner, increased detachment in a dose and time-dependent manner, caused apoptosis and inhibited cell invasion in both cell lines. In addition, Y15 treatment decreased autophosphorylation of FAK in a dose-dependent manner and changed cell morphology by causing cell rounding in DBTRG and U87 cells. Administration of Y15 significantly decreased subcutaneous DBTRG tumor growth with decreased Y397-FAK autophosphorylation, activated caspase-3 and PARP. Y15 was administered in an orthotopic glioma model, leading to an increase in mouse survival. The combination of Y15 with temozolomide was more effective than either agent alone in decreasing viability and activating caspase-8 in DBTRG and U87 cells in vitro. In addition, the combination of Y15 and temozolomide synergistically blocked U87 brain tumor growth in vivo. Thus, pharmacologic blockade of FAK autophosphorylation with the oral administration of a small molecule inhibitor Y15 has a potential to be an effective therapy approach for glioblastoma either alone or in combination with chemotherapy agents such as temozolomide. PMID:23243059

  1. Pharmacologic blockade of FAK autophosphorylation decreases human glioblastoma tumor growth and synergizes with temozolomide.

    Science.gov (United States)

    Golubovskaya, Vita M; Huang, Grace; Ho, Baotran; Yemma, Michael; Morrison, Carl D; Lee, Jisook; Eliceiri, Brian P; Cance, William G

    2013-02-01

    Malignant gliomas are characterized by aggressive tumor growth with a mean survival of 15 to 18 months and frequently developed resistance to temozolomide. Therefore, strategies that sensitize glioma cells to temozolomide have a high translational impact. We have studied focal adhesion kinase (FAK), a tyrosine kinase and emerging therapeutic target that is known to be highly expressed and activated in glioma. In this report, we tested the FAK autophosphorylation inhibitor, Y15, in DBTRG and U87 glioblastoma cells. Y15 significantly decreased viability and clonogenicity in a dose-dependent manner, increased detachment in a dose- and time-dependent manner, caused apoptosis, and inhibited cell invasion in both cell lines. In addition, Y15 treatment decreased autophosphorylation of FAK in a dose-dependent manner and changed cell morphology by causing cell rounding in DBTRG and U87 cells. Administration of Y15 significantly decreased subcutaneous DBTRG tumor growth with decreased Y397-FAK autophosphorylation, activated caspase-3 and PARP. Y15 was administered in an orthotopic glioma model, leading to an increase in mouse survival. The combination of Y15 with temozolomide was more effective than either agent alone in decreasing viability and activating caspase-8 in DBTRG and U87 cells in vitro. In addition, the combination of Y15 and temozolomide synergistically blocked U87 brain tumor growth in vivo. Thus, pharmacologic blockade of FAK autophosphorylation with the oral administration of a small-molecule inhibitor Y15 has a potential to be an effective therapy approach for glioblastoma either alone or in combination with chemotherapy agents such as temozolomide.

  2. Paeonia lactiflora Enhances the Adhesion of Trophoblast to the Endometrium via Induction of Leukemia Inhibitory Factor Expression.

    Directory of Open Access Journals (Sweden)

    Hee-Jung Choi

    Full Text Available In the present study, we investigated the role of Paeonia lactiflora Pall. extract on embryo implantation in vitro and in vivo. A polysaccharides depleted-water extract of P. lactiflora (PL-PP increased LIF expression in human endometrial Ishikawa cells at non-cytotoxic doses. PL-PP significantly increased the adhesion of the human trophectoderm-derived JAr spheroids to endometrial Ishikawa cells. PL-PP-induced LIF expression was decreased in the presence of a p38 kinase inhibitor SB203580 and an MEK/ERK inhibitor U0126. Furthermore, endometrial LIF knockdown by shRNA reduced the expression of integrins β3 and β5 and adhesion of JAr spheroids to Ishikawa cells. In vivo administration of PL-PP restored the implantation of mouse blastocysts in a mifepristone-induced implantation failure mice model. Our results demonstrate that PL-PP increases LIF expression via the p38 and MEK/ERK pathways and favors trophoblast adhesion to endometrial cells.

  3. Regulation of cell adhesion strength by peripheral focal adhesion distribution.

    Science.gov (United States)

    Elineni, Kranthi Kumar; Gallant, Nathan D

    2011-12-21

    Cell adhesion to extracellular matrices is a tightly regulated process that involves the complex interplay between biochemical and mechanical events at the cell-adhesive interface. Previous work established the spatiotemporal contributions of adhesive components to adhesion strength and identified a nonlinear dependence on cell spreading. This study was designed to investigate the regulation of cell-adhesion strength by the size and position of focal adhesions (FA). The cell-adhesive interface was engineered to direct FA assembly to the periphery of the cell-spreading area to delineate the cell-adhesive area from the cell-spreading area. It was observed that redistributing the same adhesive area over a larger cell-spreading area significantly enhanced cell-adhesion strength, but only up to a threshold area. Moreover, the size of the peripheral FAs, which was interpreted as an adhesive patch, did not directly govern the adhesion strength. Interestingly, this is in contrast to the previously reported functional role of FAs in regulating cellular traction where sizes of the peripheral FAs play a critical role. These findings demonstrate, to our knowledge for the first time, that two spatial regimes in cell-spreading area exist that uniquely govern the structure-function role of FAs in regulating cell-adhesion strength.

  4. Mapping cell surface adhesion by rotation tracking and adhesion footprinting

    Science.gov (United States)

    Li, Isaac T. S.; Ha, Taekjip; Chemla, Yann R.

    2017-03-01

    Rolling adhesion, in which cells passively roll along surfaces under shear flow, is a critical process involved in inflammatory responses and cancer metastasis. Surface adhesion properties regulated by adhesion receptors and membrane tethers are critical in understanding cell rolling behavior. Locally, adhesion molecules are distributed at the tips of membrane tethers. However, how functional adhesion properties are globally distributed on the individual cell’s surface is unknown. Here, we developed a label-free technique to determine the spatial distribution of adhesive properties on rolling cell surfaces. Using dark-field imaging and particle tracking, we extract the rotational motion of individual rolling cells. The rotational information allows us to construct an adhesion map along the contact circumference of a single cell. To complement this approach, we also developed a fluorescent adhesion footprint assay to record the molecular adhesion events from cell rolling. Applying the combination of the two methods on human promyelocytic leukemia cells, our results surprisingly reveal that adhesion is non-uniformly distributed in patches on the cell surfaces. Our label-free adhesion mapping methods are applicable to the variety of cell types that undergo rolling adhesion and provide a quantitative picture of cell surface adhesion at the functional and molecular level.

  5. Adhesive particle shielding

    Science.gov (United States)

    Klebanoff, Leonard Elliott; Rader, Daniel John; Walton, Christopher; Folta, James

    2009-01-06

    An efficient device for capturing fast moving particles has an adhesive particle shield that includes (i) a mounting panel and (ii) a film that is attached to the mounting panel wherein the outer surface of the film has an adhesive coating disposed thereon to capture particles contacting the outer surface. The shield can be employed to maintain a substantially particle free environment such as in photolithographic systems having critical surfaces, such as wafers, masks, and optics and in the tools used to make these components, that are sensitive to particle contamination. The shield can be portable to be positioned in hard-to-reach areas of a photolithography machine. The adhesive particle shield can incorporate cooling means to attract particles via the thermophoresis effect.

  6. Dystroglycan versatility in cell adhesion: a tale of multiple motifs

    Directory of Open Access Journals (Sweden)

    Winder Steve J

    2010-02-01

    Full Text Available Abstract Dystroglycan is a ubiquitously expressed heterodimeric adhesion receptor. The extracellular α-subunit makes connections with a number of laminin G domain ligands including laminins, agrin and perlecan in the extracellular matrix and the transmembrane β-subunit makes connections to the actin filament network via cytoskeletal linkers including dystrophin, utrophin, ezrin and plectin, depending on context. Originally discovered as part of the dystrophin glycoprotein complex of skeletal muscle, dystroglycan is an important adhesion molecule and signalling scaffold in a multitude of cell types and tissues and is involved in several diseases. Dystroglycan has emerged as a multifunctional adhesion platform with many interacting partners associating with its short unstructured cytoplasmic domain. Two particular hotspots are the cytoplasmic juxtamembrane region and at the very carboxy terminus of dystroglycan. Regions which between them have several overlapping functions: in the juxtamembrane region; a nuclear localisation signal, ezrin/radixin/moesin protein, rapsyn and ERK MAP Kinase binding function, and at the C terminus a regulatory tyrosine governing WW, SH2 and SH3 domain interactions. We will discuss the binding partners for these motifs and how their interactions and regulation can modulate the involvement of dystroglycan in a range of different adhesion structures and functions depending on context. Thus dystroglycan presents as a multifunctional scaffold involved in adhesion and adhesion-mediated signalling with its functions under exquisite spatio-temporal regulation.

  7. Regulation of embryonic cell adhesion by the prion protein.

    Directory of Open Access Journals (Sweden)

    Edward Málaga-Trillo

    2009-03-01

    Full Text Available Prion proteins (PrPs are key players in fatal neurodegenerative disorders, yet their physiological functions remain unclear, as PrP knockout mice develop rather normally. We report a strong PrP loss-of-function phenotype in zebrafish embryos, characterized by the loss of embryonic cell adhesion and arrested gastrulation. Zebrafish and mouse PrP mRNAs can partially rescue this knockdown phenotype, indicating conserved PrP functions. Using zebrafish, mouse, and Drosophila cells, we show that PrP: (1 mediates Ca(+2-independent homophilic cell adhesion and signaling; and (2 modulates Ca(+2-dependent cell adhesion by regulating the delivery of E-cadherin to the plasma membrane. In vivo time-lapse analyses reveal that the arrested gastrulation in PrP knockdown embryos is due to deficient morphogenetic cell movements, which rely on E-cadherin-based adhesion. Cell-transplantation experiments indicate that the regulation of embryonic cell adhesion by PrP is cell-autonomous. Moreover, we find that the local accumulation of PrP at cell contact sites is concomitant with the activation of Src-related kinases, the recruitment of reggie/flotillin microdomains, and the reorganization of the actin cytoskeleton, consistent with a role of PrP in the modulation of cell adhesion via signaling. Altogether, our data uncover evolutionarily conserved roles of PrP in cell communication, which ultimately impinge on the stability of adherens cell junctions during embryonic development.

  8. [Molecular basis of red blood cell adhesion to endothelium].

    Science.gov (United States)

    Wautier, J-L; Wautier, M-P

    2011-01-01

    The extent of red blood cell adhesion is correlated with the incidence of vascular complications and the severity of the disease. Patients with sickle cell anemia (HbSS) experience vasoocclusive episodes. The adhesion of RBCs from HbSS patients is increased and related to VLA-4 exposure, which binds to vascular cell adhesion molecule (VCAM-1). Inter Cellular Adhesion Molecule (ICAM-1), CD31, CD36 and glycans are potential receptors for PfEMP1 of RBCs parasited by plasmodium falciparum. The incidence of vascular complications is very high in patients with diabetes mellitus. RBC adhesion is increased and statistically correlated with the severity of the angiopathy. Glycation of RBC membrane proteins is responsible for binding to the receptor for advanced glycation end products (RAGE). Polycythemia Vera (PV) is the most frequent myeloproliferative disorder and characterized by a high occurrence of thrombosis of mesenteric and cerebral vessels. PV is due to a mutation of the Janus kinase 2 (JAK2 V617F). This mutation stimulates erythropoiesis and is the cause of Lu/BCAM (CD239) phosphorylation, which potentiated the interaction with laminin alpha 5. The couple laminin alpha 5 endothelial and phosphorylated Lu/BCAM explained the increased adhesion of RBCs from patients PV to endothelium.

  9. Using Adhesive Patterning to Construct 3D Paper Microfluidic Devices.

    Science.gov (United States)

    Kalish, Brent; Tsutsui, Hideaki

    2016-04-01

    We demonstrate the use of patterned aerosol adhesives to construct both planar and nonplanar 3D paper microfluidic devices. By spraying an aerosol adhesive through a metal stencil, the overall amount of adhesive used in assembling paper microfluidic devices can be significantly reduced. We show on a simple 4-layer planar paper microfluidic device that the optimal adhesive application technique and device construction style depends heavily on desired performance characteristics. By moderately increasing the overall area of a device, it is possible to dramatically decrease the wicking time and increase device success rates while also reducing the amount of adhesive required to keep the device together. Such adhesive application also causes the adhesive to form semi-permanent bonds instead of permanent bonds between paper layers, enabling single-use devices to be non-destructively disassembled after use. Nonplanar 3D origami devices also benefit from the semi-permanent bonds during folding, as it reduces the likelihood that unrelated faces may accidently stick together. Like planar devices, nonplanar structures see reduced wicking times with patterned adhesive application vs uniformly applied adhesive.

  10. Adhesion in hydrogel contacts

    Science.gov (United States)

    Torres, J. R.; Jay, G. D.; Kim, K.-S.; Bothun, G. D.

    2016-05-01

    A generalized thermomechanical model for adhesion was developed to elucidate the mechanisms of dissipation within the viscoelastic bulk of a hyperelastic hydrogel. Results show that in addition to the expected energy release rate of interface formation, as well as the viscous flow dissipation, the bulk composition exhibits dissipation due to phase inhomogeneity morphological changes. The mixing thermodynamics of the matrix and solvent determines the dynamics of the phase inhomogeneities, which can enhance or disrupt adhesion. The model also accounts for the time-dependent behaviour. A parameter is proposed to discern the dominant dissipation mechanism in hydrogel contact detachment.

  11. PI3K{gamma} activation by CXCL12 regulates tumor cell adhesion and invasion

    Energy Technology Data Exchange (ETDEWEB)

    Monterrubio, Maria; Mellado, Mario; Carrera, Ana C. [Department of Immunology and Oncology, Centro Nacional de Biotecnologia/CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain); Rodriguez-Frade, Jose Miguel, E-mail: jmrfrade@cnb.csic.es [Department of Immunology and Oncology, Centro Nacional de Biotecnologia/CSIC, Campus de Cantoblanco, E-28049 Madrid (Spain)

    2009-10-16

    Tumor dissemination is a complex process, in which certain steps resemble those in leukocyte homing. Specific chemokine/chemokine receptor pairs have important roles in both processes. CXCL12/CXCR4 is the most commonly expressed chemokine/chemokine receptor pair in human cancers, in which it regulates cell adhesion, extravasation, metastatic colonization, angiogenesis, and proliferation. All of these processes require activation of signaling pathways that include G proteins, phosphatidylinositol-3 kinase (PI3K), JAK kinases, Rho GTPases, and focal adhesion-associated proteins. We analyzed these pathways in a human melanoma cell line in response to CXCL12 stimulation, and found that PI3K{gamma} regulates tumor cell adhesion through mechanisms different from those involved in cell invasion. Our data indicate that, following CXCR4 activation after CXCL12 binding, the invasion and adhesion processes are regulated differently by distinct downstream events in these signaling cascades.

  12. Differential regulation of adhesion complex turnover by ROCK1 and ROCK2.

    Directory of Open Access Journals (Sweden)

    Frances E Lock

    Full Text Available BACKGROUND: ROCK1 and ROCK2 are serine/threonine kinases that function downstream of the small GTP-binding protein RhoA. Rho signalling via ROCK regulates a number of cellular functions including organisation of the actin cytoskeleton, cell adhesion and cell migration. METHODOLOGY/PRINCIPAL FINDINGS: In this study we use RNAi to specifically knockdown ROCK1 and ROCK2 and analyse their role in assembly of adhesion complexes in human epidermal keratinocytes. We observe that loss of ROCK1 inhibits signalling via focal adhesion kinase resulting in a failure of immature adhesion complexes to form mature stable focal adhesions. In contrast, loss of ROCK2 expression results in a significant reduction in adhesion complex turnover leading to formation of large, stable focal adhesions. Interestingly, loss of either ROCK1 or ROCK2 expression significantly impairs cell migration indicating both ROCK isoforms are required for normal keratinocyte migration. CONCLUSIONS: ROCK1 and ROCK2 have distinct and separate roles in adhesion complex assembly and turnover in human epidermal keratinocytes.

  13. A Study on Adhesive Properties of Materials Based on Biomimetic Results of Gecko's Feet

    Institute of Scientific and Technical Information of China (English)

    Hao Zhang; Zhendong Dai; Stanislav Gorb

    2004-01-01

    Many animals have a magic ability to move or hold on ceilings and walls because of the design of their adhesive pads.The experiments were carried out to study the effects of material properties (elastic modulus EM and chemical components CC) and contact geometry (surface roughness, connecting stiffness) on their adhesive properties. The adhesion of the lowest EM samples is the highest ( 15 kPa) and the surface roughness has strong effects on adhesion and the adhesion decreases to 1.5 kPa for the highest EM samples. The adhesive forces are heavily influenced by CC of polyurethane. Surface roughness heavily influences the adhesion and when the roughness is higher than Ra 0.3 μm, the obtained adhesion of the samples is the same. The adhesion does not change with the normal forces when a sphere is used to contact with flat PU samples. But when the two matually contact surfaces are flat, the adhesion of a material increases with the normal load at first and then turns to slightly raise. The adhesion of them is the same for the contact angles from 1 to 3 degree when the samples are softly connected. But when they are adhesive hardly to each other the adhesion decreases with increase of the contact angle.

  14. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives

    OpenAIRE

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-01-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structur...

  15. Switchable bio-inspired adhesives

    Science.gov (United States)

    Kroner, Elmar

    2015-03-01

    Geckos have astonishing climbing abilities. They can adhere to almost any surface and can run on walls and even stick to ceilings. The extraordinary adhesion performance is caused by a combination of a complex surface pattern on their toes and the biomechanics of its movement. These biological dry adhesives have been intensely investigated during recent years because of the unique combination of adhesive properties. They provide high adhesion, allow for easy detachment, can be removed residue-free, and have self-cleaning properties. Many aspects have been successfully mimicked, leading to artificial, bio-inspired, patterned dry adhesives, and were addressed and in some aspects they even outperform the adhesion capabilities of geckos. However, designing artificial patterned adhesion systems with switchable adhesion remains a big challenge; the gecko's adhesion system is based on a complex hierarchical surface structure and on advanced biomechanics, which are both difficult to mimic. In this paper, two approaches are presented to achieve switchable adhesion. The first approach is based on a patterned polydimethylsiloxane (PDMS) polymer, where adhesion can be switched on and off by applying a low and a high compressive preload. The switch in adhesion is caused by a reversible mechanical instability of the adhesive silicone structures. The second approach is based on a composite material consisting of a Nickel- Titanium (NiTi) shape memory alloy and a patterned adhesive PDMS layer. The NiTi alloy is trained to change its surface topography as a function of temperature, which results in a change of the contact area and of alignment of the adhesive pattern towards a substrate, leading to switchable adhesion. These examples show that the unique properties of bio-inspired adhesives can be greatly improved by new concepts such as mechanical instability or by the use of active materials which react to external stimuli.

  16. Human β-Defensin 3 Reduces TNF-α-Induced Inflammation and Monocyte Adhesion in Human Umbilical Vein Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Tianying Bian

    2017-01-01

    Full Text Available The aim of this study was to investigate the role of human β-defensin 3 (hBD3 in the initiation stage of atherosclerosis with human umbilical vein endothelial cells (HUVECs triggered by tumor necrosis factor- (TNF- α. The effects of hBD3 on TNF-α-induced endothelial injury and inflammatory response were evaluated. Our data revealed that first, hBD3 reduced the production of interleukin-6 (IL-6, IL-8, monocyte chemoattractant protein-1 (MCP-1, and macrophage migration inhibitory factor (MIF in HUVECs in a dose-dependent manner. In addition, hBD3 significantly prevented intracellular reactive oxygen species (ROS production by HUVECs. Second, western blot analysis demonstrated that hBD3 dose-dependently suppressed the protein levels of intracellular adhesion molecule-1 (ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1 in TNF-α-induced HUVECs. As a result, hBD3 inhibited monocyte adhesion to TNF-α-treated endothelial cells. Additionally, hBD3 suppressed TNF-α-induced F-actin reorganization in HUVECs. Third, hBD3 markedly inhibited NF-κB activation by decreasing the phosphorylation of IKK-α/β, IκB, and p65 subunit within 30 min. Moreover, the phosphorylation of p38 and c-Jun N-terminal protein kinase (JNK in the mitogen-activated protein kinase (MAPK pathway were also inhibited by hBD3 in HUVECs. In conclusion, hBD3 exerts anti-inflammatory and antioxidative effects in endothelial cells in response to TNF-α by inhibiting NF-κB and MAPK signaling.

  17. Human β-Defensin 3 Reduces TNF-α-Induced Inflammation and Monocyte Adhesion in Human Umbilical Vein Endothelial Cells

    Science.gov (United States)

    Bian, Tianying; Li, Houxuan; Zhou, Qian; Ni, Can; Zhang, Yangheng

    2017-01-01

    The aim of this study was to investigate the role of human β-defensin 3 (hBD3) in the initiation stage of atherosclerosis with human umbilical vein endothelial cells (HUVECs) triggered by tumor necrosis factor- (TNF-) α. The effects of hBD3 on TNF-α-induced endothelial injury and inflammatory response were evaluated. Our data revealed that first, hBD3 reduced the production of interleukin-6 (IL-6), IL-8, monocyte chemoattractant protein-1 (MCP-1), and macrophage migration inhibitory factor (MIF) in HUVECs in a dose-dependent manner. In addition, hBD3 significantly prevented intracellular reactive oxygen species (ROS) production by HUVECs. Second, western blot analysis demonstrated that hBD3 dose-dependently suppressed the protein levels of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in TNF-α-induced HUVECs. As a result, hBD3 inhibited monocyte adhesion to TNF-α-treated endothelial cells. Additionally, hBD3 suppressed TNF-α-induced F-actin reorganization in HUVECs. Third, hBD3 markedly inhibited NF-κB activation by decreasing the phosphorylation of IKK-α/β, IκB, and p65 subunit within 30 min. Moreover, the phosphorylation of p38 and c-Jun N-terminal protein kinase (JNK) in the mitogen-activated protein kinase (MAPK) pathway were also inhibited by hBD3 in HUVECs. In conclusion, hBD3 exerts anti-inflammatory and antioxidative effects in endothelial cells in response to TNF-α by inhibiting NF-κB and MAPK signaling.

  18. Switchable Adhesion in Vacuum Using Bio-Inspired Dry Adhesives.

    Science.gov (United States)

    Purtov, Julia; Frensemeier, Mareike; Kroner, Elmar

    2015-11-01

    Suction based attachment systems for pick and place handling of fragile objects like glass plates or optical lenses are energy-consuming and noisy and fail at reduced air pressure, which is essential, e.g., in chemical and physical vapor deposition processes. Recently, an alternative approach toward reversible adhesion of sensitive objects based on bioinspired dry adhesive structures has emerged. There, the switching in adhesion is achieved by a reversible buckling of adhesive pillar structures. In this study, we demonstrate that these adhesives are capable of switching adhesion not only in ambient air conditions but also in vacuum. Our bioinspired patterned adhesive with an area of 1 cm(2) provided an adhesion force of 2.6 N ± 0.2 N in air, which was reduced to 1.9 N ± 0.2 N if measured in vacuum. Detachment was induced by buckling of the structures due to a high compressive preload and occurred, independent of air pressure, at approximately 0.9 N ± 0.1 N. The switch in adhesion was observed at a compressive preload between 5.6 and 6.0 N and was independent of air pressure. The difference between maximum adhesion force and adhesion force after buckling gives a reasonable window of operation for pick and place processes. High reversibility of the switching behavior is shown over 50 cycles in air and in vacuum, making the bioinspired switchable adhesive applicable for handling operations of fragile objects.

  19. Hyperphosphorylated FAK Delocalizes from Focal Adhesions to Membrane Ruffles

    Directory of Open Access Journals (Sweden)

    Abdelkader Hamadi

    2010-01-01

    Full Text Available Cell adhesion and migration are key determinants in tumor metastasis. Adherence of tumor cell to the extracellular matrix is mediated via integrin containing focal adhesions (FAs. Binding of integrins to ECM triggers phosphorylation of two major components of FAs, focal adhesion kinase (FAK and Src, activating downstream signaling pathway which leads to FA disassembly and cell migration. In this paper, we analyze how phosphorylation of FAK regulates its trafficking at FAs in living human astrocytoma cells. Upon pervanadate-induced FAK phosphorylation, phosphorylated FAK appeared highly expressed at newly formed membrane ruffles. This effect was abolished in presence of the specific Src inhibitor PP2. Our findings demonstrate that upon phosphorylation, FAK delocalizes from FAs to membrane ruffles.

  20. Syndecan 4 heparan sulfate proteoglycan is a selectively enriched and widespread focal adhesion component

    DEFF Research Database (Denmark)

    Woods, A; Couchman, J R

    1994-01-01

    Focal adhesion formation in fibroblasts results from complex transmembrane signaling processes initiated by extracellular matrix molecules. Although a role for integrins with attendant tyrosine kinases has been established, there is evidence that cell surface heparan sulfate proteoglycans (HSPGs......) are also involved with an associated role of protein kinase C. The identity of the proteoglycan has remained elusive, but we now report that syndecan 4 (ryudocan/amphiglycan) is present in focal adhesions of a number of cell types. Affinity-purified antibodies raised against a unique portion...

  1. Adhesive tape exfoliation

    DEFF Research Database (Denmark)

    Bohr, Jakob

    2015-01-01

    Single-crystal graphite can be cleaved by the use of an adhesive tape. This was also the initial route for obtaining graphene, a one-layer thick graphite slab. In this letter a few simple and fun considerations are presented in an attempt to shed some light on why this procedure is successful...

  2. Biological adhesion of Parthenocissus tricuspidata

    Directory of Open Access Journals (Sweden)

    He Tianxian

    2011-01-01

    Full Text Available Parthenocissus tricuspidata is a climbing plant of the grape family. It can climb with its adhesive discs on different substrates such as stone mountains, roadside stone banks, exterior walls of buildings, thereby withstanding strong winds and storms without detachment. The details about the adhesion process of Parthenocissus tricuspidata are not yet entirely understood. We studied the component-structure-property relationship of the adhesive discs in detail and propose a twostage model to describe the biological adhesion: (i structural contact and (ii adhesive action. These two stages and their variations play an important role for the attaching of the adhesive disc to different structural surfaces. We believe that in Parthenocissus tricuspidata different mechanisms work together to allow the adhesive disc to climb on various vertical substrates and reveal strong adhesive properties.

  3. Pharmacological blockade of FAK autophosphorylation decreases human glioblastoma tumor growth and synergizes with temozolomide

    OpenAIRE

    2012-01-01

    Malignant gliomas are characterized by aggressive tumor growth with a mean survival of 15–18 months and frequently developed resistance to temozolomide. Therefore, strategies that sensitize glioma cells to temozolomide have a high translational impact. We have studied focal adhesion kinase (FAK), a tyrosine kinase and emerging therapeutic target that is known to be highly expressed and activated in glioma. In this report we tested the FAK autophosphorylation inhibitor, Y15 in DBTRG and U87 gl...

  4. Regulation of brain tumor dispersal by NKCC1 through a novel role in focal adhesion regulation.

    Directory of Open Access Journals (Sweden)

    Tomas Garzon-Muvdi

    Full Text Available Glioblastoma (GB is a highly invasive and lethal brain tumor due to its universal recurrence. Although it has been suggested that the electroneutral Na(+-K(+-Cl(- cotransporter 1 (NKCC1 can play a role in glioma cell migration, the precise mechanism by which this ion transporter contributes to GB aggressiveness remains poorly understood. Here, we focused on the role of NKCC1 in the invasion of human primary glioma cells in vitro and in vivo. NKCC1 expression levels were significantly higher in GB and anaplastic astrocytoma tissues than in grade II glioma and normal cortex. Pharmacological inhibition and shRNA-mediated knockdown of NKCC1 expression led to decreased cell migration and invasion in vitro and in vivo. Surprisingly, knockdown of NKCC1 in glioma cells resulted in the formation of significantly larger focal adhesions and cell traction forces that were approximately 40% lower than control cells. Epidermal growth factor (EGF, which promotes migration of glioma cells, increased the phosphorylation of NKCC1 through a PI3K-dependant mechanism. This finding is potentially related to WNK kinases. Taken together, our findings suggest that NKCC1 modulates migration of glioma cells by two distinct mechanisms: (1 through the regulation of focal adhesion dynamics and cell contractility and (2 through regulation of cell volume through ion transport. Due to the ubiquitous expression of NKCC1 in mammalian tissues, its regulation by WNK kinases may serve as new therapeutic targets for GB aggressiveness and can be exploited by other highly invasive neoplasms.

  5. Underwater Reversible Adhesion Between Oppositely Charged Weak Polyelectrolytes

    Science.gov (United States)

    Alfhaid, Latifah; Geoghegan, Mark; Williams, Nicholas; Seddon, William

    2015-03-01

    Force-distance data has shown that the adhesion between two oppositely charged polyelectrolytes: poly(methacrylic acid) (PMAA, a polyacid) and poly[2-(diethylamino)ethyl methacrylate] (PDEAEMA, a polybase), was controllable by varying the pH level of their surrounding. Accordingly, adhesive force at the interface between these two polymers was higher inside basic surroundings at pH 6 and 7, and then it started to decrease at pH level below 3 and above 8. Stimulating adhesion between PMAA gel and PDEAEMA brushes by adding salt to their surrounded water has only a limited effect on the adhesive force between them, contradicting previous results. Increasing the molar concentration of sodium chloride (NaCl) in the surrounded water of these two polymers from 0.1 to 1M did not decrease the adhesion forces between a PMAA gel and a grafted PDEAEMA layer (brush). The JKR equation was used to evaluate the adhesion forces between the polymer gel and the brushes and it was observed that the adhesion increased with the elastic modulus of the gel decreased.

  6. Resolving fundamental limits of adhesive bonding in microfabrication.

    Energy Technology Data Exchange (ETDEWEB)

    Hall, Jessica S.; Frischknecht, Amalie Lucile; Emerson, John Allen; Adkins, Douglas Ray; Kent, Michael Stuart; Read, Douglas H.; Giunta, Rachel Knudsen; Lamppa, Kerry P.; Kawaguchi, Stacie; Holmes, Melissa A.

    2004-04-01

    As electronic and optical components reach the micro- and nanoscales, efficient assembly and packaging require the use of adhesive bonds. This work focuses on resolving several fundamental issues in the transition from macro- to micro- to nanobonding. A primary issue is that, as bondline thicknesses decrease, knowledge of the stability and dewetting dynamics of thin adhesive films is important to obtain robust, void-free adhesive bonds. While researchers have studied dewetting dynamics of thin films of model, non-polar polymers, little experimental work has been done regarding dewetting dynamics of thin adhesive films, which exhibit much more complex behaviors. In this work, the areas of dispensing small volumes of viscous materials, capillary fluid flow, surface energetics, and wetting have all been investigated. By resolving these adhesive-bonding issues, we are allowing significantly smaller devices to be designed and fabricated. Simultaneously, we are increasing the manufacturability and reliability of these devices.

  7. ADHESION-INDUCE PROTEIN TYROSINE PHOSPHORY-LATION IS ASSOCIATED WITH INVASIVE AND METASTATIC POTENTIALS IN B16-BL6 MELANOMA CELLS

    Institute of Scientific and Technical Information of China (English)

    Yan Chunhong; Han Rui

    1998-01-01

    Objective: The interaction of cancer cell with extracellular matrix (ECM) happens as an earlier and specific event in the invasive and metastatic cascade. To explore the key element(s) in cancer metastasis and observe the cell-ECM interaction and its role. Methods:To interrupt the cell-ECM interaction by suppression of adhesion-induced protein tyrosine phosphorylation with protein tyrosine kinase inhibitor genistein in B16-B16mouse melanoma cells. Results: When B16-BL6 cells attached to Matrigel, a solubilized basement membrane preparation from EHS sarcoma, a 125 kDa protein increased its phosphotyrosine content dramatically. In contrast, when the cells were pretreated with 20μM or 30μM genistein for 3 days, it was revealed a less increase in the phosphotyrosine content of this 125 kDa protein inresponse to cell attachment to ECM was revealed with immunoblot analysis. Accompanied by the lower level of adhesion-induced protein tyrosine phosphorylation the genistein-treated cells exhibited a decrease in their capabilities of adhesion to Matrigel and invasion through reconstituted basement membrane. The potentials of and forming lung metastatic nodules were also shown to be decreased dramatically in these genistein-treated cells.Conclusion: It was suggested that protein tyrosine phosphorylation in cell-ECM interaction might be associated with invasive and metastatic potentials in cancer cells.

  8. Plant protein kinase genes induced by drought, high salt and cold stresses

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Drought, high salt and cold are three different kinds of environment stresses that severely influence the growth, development and productivity of crops. They all decrease the water state of plant cells, and consequently result in the harm of plant from water deficit. Several genes encoding protein kinases and induced by drought, high salt and low temperature have been isolated from Arabidopsis. These protein kinases include receptor protein kinase (RPK), MAP kinases, ribosomal-protein kinases and transcription-regulation protein kinase. The expression features of these genes and the regulatory roles of these protein kinases in stress response and signal transduction are discussed.

  9. Staphylococcus epidermidis adhesion on hydrophobic and hydrophilic textured biomaterial surfaces.

    Science.gov (United States)

    Xu, Li-Chong; Siedlecki, Christopher A

    2014-06-01

    It is of great interest to use nano- or micro-structured surfaces to inhibit microbial adhesion and biofilm formation and thereby to prevent biomaterial-associated infection, without modification of the surface chemistry or bulk properties of the materials and without use of the drugs. Our previous study showed that a submicron textured polyurethane surface can inhibit staphylococcal bacterial adhesion and biofilm formation. To further understand the effect of the geometry of textures on bacterial adhesion as well as the underlying mechanism, in this study, submicron and micron textured polyurethane surfaces featuring ordered arrays of pillars were fabricated and modified to have different wettabilities. All the textured surfaces were originally hydrophobic and showed significant reductions in Staphylococcus epidermidis RP62A adhesion in phosphate buffered saline or 25% platelet poor plasma solutions under shear, as compared to smooth surfaces. After being subjected to an air glow discharge plasma treatment, all polyurethane surfaces were modified to hydrophilic, and reductions in bacterial adhesion on surfaces were subsequently found to be dependent on the size of the patterns. The submicron patterned surfaces reduced bacterial adhesion, while the micron patterned surfaces led to increased bacterial adhesion. The extracellular polymeric substances (EPS) from the S. epidermidis cell surfaces were extracted and purified, and were coated on a glass colloidal surface so that the adhesion force and separation energy in interactions of the EPS and the surface could be measured by colloidal probe atomic force microscopy. These results were consistent with the bacterial adhesion observations. Overall, the data suggest that the increased surface hydrophobicity and the decreased availability of the contact area contributes to a reduction in bacterial adhesion to the hydrophobic textured surfaces, while the availability of the contact area is the primary determinant factor

  10. Thymidine kinases in archaea

    DEFF Research Database (Denmark)

    Clausen, A.R.; Matakos, A.; Sandrini, Michael;

    2006-01-01

    Twenty-six fully sequenced archaeal genomes were searched for genes coding for putative deoxyribonucleoside kinases (dNKs). We identified only 5 human-like thymidine kinase 1 genes (TK1s) and none for non-TK1 kinases. Four TK1s were identified in the Euryarchaea and one was found in the Crenarchaea...... that a functional deoxyribonucleoside salvage pathway is not crucial for the archaeal cell....

  11. Analysis of the surface effects on adhesion in MEMS structures

    Science.gov (United States)

    Rusu, F.; Pustan, M.; Bîrleanu, C.; Müller, R.; Voicu, R.; Baracu, A.

    2015-12-01

    One of the main failure causes in microelectromechanical systems (MEMS) is stiction. Stiction is the adhesion of contacting surfaces due to surface forces. Adhesion force depends on the operating conditions and is influenced by the contact area. In this study, the adhesion force between MEMS materials and the AFM tips is analyzed using the spectroscopy in point mode of the AFM. The aim is to predict the stiction failure mode in MEMS. The investigated MEMS materials are silicon, polysilicon, platinum, aluminum, and gold. Three types of investigations were conducted. The first one aimed to determine the variation of the adhesion force with respect to the variation of the roughness. The roughness has a strong influence on the adhesion because the contact area between components increases if the roughness decreases. The second type of investigation aimed to determine the adhesion force in multiple points of each considered sample. The values obtained experimentally for the adhesion force were also validated using the JKR and DMT models. The third type of investigation was conducted with the purpose of determining the influence of the temperature on the adhesion force.

  12. Management of adhesive capsulitis

    Directory of Open Access Journals (Sweden)

    Stupay KL

    2015-08-01

    Full Text Available Kristen L Stupay,1 Andrew S Neviaser2 1Tulane University School of Medicine, New Orleans, LA, USA; 2George Washington University Medical Faculty Associates, Washington, DC, USA Abstract: Adhesive capsulitis of the shoulder is a condition of capsular contracture that reduces both active and passive glenohumeral motion. The cause of adhesive capsulitis is not known but it is strongly associated with endocrine abnormalities such as diabetes. Diverse terminology and the absence of definitive criteria for diagnosis make evaluating treatment modalities difficult. Many treatment methods have been reported, most with some success, but few have been proved to alter the natural course of this disease. Most afflicted patients will achieve acceptable shoulder function without surgery. Those who remain debilitated after 8–12 months are reasonable candidates for invasive treatments. Here, the various treatment methods and the data to support their use are reviewed. Keywords: frozen shoulder, stiff shoulder, periarthritis, painful shoulder 

  13. Polymerization behavior within adhesive layer of one- and two-step self-etch adhesives: a micro-Raman spectroscopic study.

    Science.gov (United States)

    Sakano, Wakae; Nakajima, Masatoshi; Prasansuttiporn, Taweesak; Foxton, Richard M; Tagami, Junji

    2013-01-01

    This study investigated the polymerization behavior within the adhesive layer of one- and two-step self-etch adhesives at the dentincomposite interface. Dentin surfaces were applied with Clearfil S(3) Bond (TS), Clearfil S(3) Bond Plus (TSP) and Clearfil SE Bond (SE), and then placed with a light-curing resin composite. After water storage for 24 h, the bonded teeth were sectioned and polished perpendicular to the adhesive interface, and the degree of conversion (DC) of the adhesive layer between the dentin and composite were determined using micro-Raman analysis. For all the adhesives, the DCs of the adhesive layers significantly decreased near the adhesive-composite join (padhesive-composite join (Pitf), TS was significantly lower than TSP and SE (padhesive could not reach maximum DC even after polymerization of the overlying resin composite.

  14. Syndecans and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Chen, L; Woods, A

    2001-01-01

    Now that transmembrane signaling through primary cell-matrix receptors, integrins, is being elucidated, attention is turning to how integrin-ligand interactions can be modulated. Syndecans are transmembrane proteoglycans implicated as coreceptors in a variety of physiological processes, including...... cell adhesion, migration, response to growth factors, development, and tumorigenesis. This review will describe this family of proteoglycans in terms of their structures and functions and their signaling in conjunction with integrins, and indicate areas for future research....

  15. FAK acts as a suppressor of RTK-MAP kinase signalling in Drosophila melanogaster epithelia and human cancer cells.

    OpenAIRE

    2014-01-01

    Receptor Tyrosine Kinases (RTKs) and Focal Adhesion Kinase (FAK) regulate multiple signalling pathways, including mitogen-activated protein (MAP) kinase pathway. FAK interacts with several RTKs but little is known about how FAK regulates their downstream signalling. Here we investigated how FAK regulates signalling resulting from the overexpression of the RTKs RET and EGFR. FAK suppressed RTKs signalling in Drosophila melanogaster epithelia by impairing MAPK pathway. This regulation was also ...

  16. The Aging Behavior of Polyurethane Adhesive in Medium

    Institute of Scientific and Technical Information of China (English)

    NI Xiaoxue; LI Xiaogang; ZHANG Sanping; QIU Dajian

    2009-01-01

    The aging behavior of polyurethane adhesive in medium was investigated and compared by means of scanning electronic microscopy(SEM),infrared spectroscopy(IR),interface analysis and shearing strength test.The experimental results show that the shear strength of polyure-thane adhesive in salt water is decreased more quickly than that in water.Na~+ and Cl~- ions could makethe polyurethane adhesive age faster and the interface metal corrosion.The high temperature acceler-ates the diffusion of water molecule,Na~+ and Cl~- ions and the degradation of the giant molecule.

  17. Prostaglandins in Cancer Cell Adhesion, Migration, and Invasion

    Directory of Open Access Journals (Sweden)

    David G. Menter

    2012-01-01

    Full Text Available Prostaglandins exert a profound influence over the adhesive, migratory, and invasive behavior of cells during the development and progression of cancer. Cyclooxygenase-2 (COX-2 and microsomal prostaglandin E2 synthase-1 (mPGES-1 are upregulated in inflammation and cancer. This results in the production of prostaglandin E2 (PGE2, which binds to and activates G-protein-coupled prostaglandin E1-4 receptors (EP1-4. Selectively targeting the COX-2/mPGES-1/PGE2/EP1-4 axis of the prostaglandin pathway can reduce the adhesion, migration, invasion, and angiogenesis. Once stimulated by prostaglandins, cadherin adhesive connections between epithelial or endothelial cells are lost. This enables cells to invade through the underlying basement membrane and extracellular matrix (ECM. Interactions with the ECM are mediated by cell surface integrins by “outside-in signaling” through Src and focal adhesion kinase (FAK and/or “inside-out signaling” through talins and kindlins. Combining the use of COX-2/mPGES-1/PGE2/EP1-4 axis-targeted molecules with those targeting cell surface adhesion receptors or their downstream signaling molecules may enhance cancer therapy.

  18. Muscle phosphorylase kinase deficiency

    DEFF Research Database (Denmark)

    Preisler, N; Orngreen, M C; Echaniz-Laguna, A;

    2012-01-01

    To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD).......To examine metabolism during exercise in 2 patients with muscle phosphorylase kinase (PHK) deficiency and to further define the phenotype of this rare glycogen storage disease (GSD)....

  19. Why do receptor-ligand bonds in cell adhesion cluster into discrete focal-adhesion sites?

    Science.gov (United States)

    Gao, Zhiwen; Gao, Yanfei

    2016-10-01

    Cell adhesion often exhibits the clustering of the receptor-ligand bonds into discrete focal-adhesion sites near the contact edge, thus resembling a rosette shape or a contracting membrane anchored by a small number of peripheral forces. The ligands on the extracellular matrix are immobile, and the receptors in the cell plasma membrane consist of two types: high-affinity integrins (that bond to the substrate ligands and are immobile) and low-affinity integrins (that are mobile and not bonded to the ligands). Thus the adhesion energy density is proportional to the high-affinity integrin density. This paper provides a mechanistic explanation for the clustering/assembling of the receptor-ligand bonds from two main points: (1) the cellular contractile force leads to the density evolution of these two types of integrins, and results into a large high-affinity integrin density near the contact edge and (2) the front of a propagating crack into a decreasing toughness field will be unstable and wavy. From this fracture mechanics perspective, the chemomechanical equilibrium is reached when a small number of patches with large receptor-ligand bond density are anticipated to form at the cell periphery, as opposed to a uniform distribution of bonds on the entire interface. Cohesive fracture simulations show that the de-adhesion force can be significantly enhanced by this nonuniform bond density field, but the de-adhesion force anisotropy due to the substrate elastic anisotropy is significantly reduced.

  20. Phosphoinositide 3-kinase regulates crosstalk between Trk A tyrosine kinase and p75(NTR)-dependent sphingolipid signaling pathways.

    Science.gov (United States)

    Bilderback, T R; Gazula, V R; Dobrowsky, R T

    2001-03-01

    The mechanism of crosstalk between signaling pathways coupled to the Trk A and p75(NTR) neurotrophin receptors in PC12 cells was examined. In response to nerve growth factor (NGF), Trk A activation inhibited p75(NTR)-dependent sphingomyelin (SM) hydrolysis. The phosphoinositide 3-kinase (PI 3-kinase) inhibitor, LY294002, reversed this inhibition suggesting that Trk A activation of PI 3-kinase is necessary to inhibit sphingolipid signaling by p75(NTR). In contrast, SM hydrolysis induced by neurotrophin-3 (NT-3), which did not activate PI-3 kinase, was uneffected by LY294002. However, transient expression of a constituitively active PI 3-kinase inhibited p75(NTR)-dependent SM hydrolysis by both NGF and NT-3. Intriguingly, NGF induced an association of activated PI 3-kinase with acid sphingomyelinase (SMase). This interaction localized to caveolae-related domains and correlated with a 50% decrease in immunoprecipitated acid SMase activity. NGF-stimulated PI 3-kinase activity was necessary for inhibition of acid SMase but was not required for ligand-induced association of the p85 subunit of PI 3-kinase with the phospholipase. Finally, this interaction was specific for NGF since EGF did not induce an association of PI 3-kinase with acid SMase. In summary, our data suggest that PI 3-kinase regulates the inhibitory crosstalk between Trk A tyrosine kinase and p75(NTR)-dependent sphingolipid signaling pathways and that this interaction localizes to caveolae-related domains.

  1. Hemocyte–hemocyte adhesion and nodulation reactions of the greater wax moth, Galleria mellonella are influenced by cholera toxin and its B-subunit

    Science.gov (United States)

    Lapointe, Jason F.; Dunphy, Gary B.; Mandato, Craig A.

    2012-01-01

    Nodulation, the lepidopteran insect immune response to large numbers of microbes in the blood (hemolymph) consists of the coordination of the blood cell (hemocyte) types the granular cells and plasmatocytes in terms of granular cell–bacteria adhesion and hemocyte–hemocyte adhesion (microaggregation). Hemocyte–microbe adhesion is influenced by the secondary messenger, cAMP, and cAMP-dependent protein kinase A. In the present study, cholera toxin, an AB5 protein known to indirectly stimulate adenylate cyclase, is used to examine the hemocyte responses to glass, bacteria and hemocyte–hemocyte microaggregates. In vitro, this toxin induces a bimodal hemocyte adhesion response that varies with the holotoxin concentration in terms of the individual and aggregated hemocyte adhesion responses: the lower CTX concentration (1.2 nM) increases microaggregate adhesion and decreases individual hemocyte binding to glass, as does higher concentrations (6–120 nM), however microaggregates induced by lower concentrations do not adhere to glass. Cholera toxin-induced microaggregation is inhibited by RGDS, suggestive of integrin involvement. In vivo, cholera toxin (1.2–120 nM) injected into larvae induces also a bimodal hemocytic response: low levels (1.2–6 nM) cause reduced hemocyte adhesion, while high levels (12–120 nM) increase hemocyte release or mobilization of adhesive hemocyte counts in the hemolymph. Increasing levels of cholera toxin concomitantly injected with the non-pathogenic bacterium, Bacillus subtilis produces a bimodal pattern in bacterial removal from the hemolymph which correlates with nodule frequency in larvae injected with cholera toxin only. The effects of higher concentrations of cholera toxin in vitro (6–120 nM) and in vivo (12–120 nM) are mediated by the B-subunit, whereas the isolated A-subunit has no effect on hemocyte activity. Cholera toxin and its individual subunits did not detectably alter levels of intracellular cAMP in the

  2. Hemocyte-hemocyte adhesion and nodulation reactions of the greater wax moth, Galleria mellonella are influenced by cholera toxin and its B-subunit.

    Science.gov (United States)

    Lapointe, Jason F; Dunphy, Gary B; Mandato, Craig A

    2012-01-01

    Nodulation, the lepidopteran insect immune response to large numbers of microbes in the blood (hemolymph) consists of the coordination of the blood cell (hemocyte) types the granular cells and plasmatocytes in terms of granular cell-bacteria adhesion and hemocyte-hemocyte adhesion (microaggregation). Hemocyte-microbe adhesion is influenced by the secondary messenger, cAMP, and cAMP-dependent protein kinase A. In the present study, cholera toxin, an AB5 protein known to indirectly stimulate adenylate cyclase, is used to examine the hemocyte responses to glass, bacteria and hemocyte-hemocyte microaggregates. In vitro, this toxin induces a bimodal hemocyte adhesion response that varies with the holotoxin concentration in terms of the individual and aggregated hemocyte adhesion responses: the lower CTX concentration (1.2 nM) increases microaggregate adhesion and decreases individual hemocyte binding to glass, as does higher concentrations (6-120 nM), however microaggregates induced by lower concentrations do not adhere to glass. Cholera toxin-induced microaggregation is inhibited by RGDS, suggestive of integrin involvement. In vivo, cholera toxin (1.2-120 nM) injected into larvae induces also a bimodal hemocytic response: low levels (1.2-6 nM) cause reduced hemocyte adhesion, while high levels (12-120 nM) increase hemocyte release or mobilization of adhesive hemocyte counts in the hemolymph. Increasing levels of cholera toxin concomitantly injected with the non-pathogenic bacterium, Bacillus subtilis produces a bimodal pattern in bacterial removal from the hemolymph which correlates with nodule frequency in larvae injected with cholera toxin only. The effects of higher concentrations of cholera toxin in vitro (6-120 nM) and in vivo (12-120 nM) are mediated by the B-subunit, whereas the isolated A-subunit has no effect on hemocyte activity. Cholera toxin and its individual subunits did not detectably alter levels of intracellular cAMP in the hemocytes, suggesting

  3. Opa+ Neisseria gonorrhoeae exhibits reduced survival in human neutrophils via Src family kinase-mediated bacterial trafficking into mature phagolysosomes.

    Science.gov (United States)

    Johnson, M Brittany; Ball, Louise M; Daily, Kylene P; Martin, Jennifer N; Columbus, Linda; Criss, Alison K

    2015-05-01

    During gonorrhoeal infection, there is a heterogeneous population of Neisseria gonorrhoeae (Gc) varied in their expression of opacity-associated (Opa) proteins. While Opa proteins are important for bacterial attachment and invasion of epithelial cells, Opa+ Gc has a survival defect after exposure to neutrophils. Here, we use constitutively Opa- and OpaD+ Gc in strain background FA1090 to show that Opa+ Gc is more sensitive to killing inside adherent, chemokine-treated primary human neutrophils due to increased bacterial residence in mature, degradative phagolysosomes that contain primary and secondary granule antimicrobial contents. Although Opa+ Gc stimulates a potent oxidative burst, neutrophil killing of Opa+ Gc was instead attributable to non-oxidative components, particularly neutrophil proteases and the bactericidal/permeability-increasing protein. Blocking interaction of Opa+ Gc with carcinoembryonic antigen-related cell adhesion molecules (CEACAMs) or inhibiting Src family kinase signalling, which is downstream of CEACAM activation, enhanced the survival of Opa+ Gc in neutrophils. Src family kinase signalling was required for fusion of Gc phagosomes with primary granules to generate mature phagolysosomes. Conversely, ectopic activation of Src family kinases or coinfection with Opa+ Gc resulted in decreased survival of Opa- Gc in neutrophils. From these results, we conclude that Opa protein expression is an important modulator of Gc survival characteristics in neutrophils by influencing phagosome dynamics and thus bacterial exposure to neutrophils' full antimicrobial arsenal.

  4. Fusicoccin A, a Phytotoxic Carbotricyclic Diterpene Glucoside of Fungal Origin, Reduces Proliferation and Invasion of Glioblastoma Cells by Targeting Multiple Tyrosine Kinases1

    Science.gov (United States)

    Bury, Marina; Andolfi, Anna; Rogister, Bernard; Cimmino, Alessio; Mégalizzi, Véronique; Mathieu, Véronique; Feron, Olivier; Evidente, Antonio; Kiss, Robert

    2013-01-01

    Glioblastoma multiforme (GBM) is a deadly cancer that possesses an intrinsic resistance to pro-apoptotic insults, such as conventional chemotherapy and radiotherapy, and diffusely invades the brain parenchyma, which renders it elusive to total surgical resection. We found that fusicoccin A, a fungal metabolite from Fusicoccum amygdali, decreased the proliferation and migration of human GBM cell lines in vitro, including several cell lines that exhibit varying degrees of resistance to pro-apoptotic stimuli. The data demonstrate that fusicoccin A inhibits GBM cell proliferation by decreasing growth rates and increasing the duration of cell division and also decreases two-dimensional (measured by quantitative video microscopy) and three-dimensional (measured by Boyden chamber assays) migration. These effects of fusicoccin A treatment translated into structural changes in actin cytoskeletal organization and a loss of GBM cell adhesion. Therefore, fusicoccin A exerts cytostatic effects but low cytotoxic effects (as demonstrated by flow cytometry). These cytostatic effects can partly be explained by the fact that fusicoccin inhibits the activities of a dozen kinases, including focal adhesion kinase (FAK), that have been implicated in cell proliferation and migration. Overexpression of FAK, a nonreceptor protein tyrosine kinase, directly correlates with the invasive phenotype of aggressive human gliomas because FAK promotes cell proliferation and migration. Fusicoccin A led to the down-regulation of FAK tyrosine phosphorylation, which occurred in both normoxic and hypoxic GBM cell culture conditions. In conclusion, the current study identifies a novel compound that could be used as a chemical template for generating cytostatic compounds designed to combat GBM. PMID:23544164

  5. Fusicoccin a, a phytotoxic carbotricyclic diterpene glucoside of fungal origin, reduces proliferation and invasion of glioblastoma cells by targeting multiple tyrosine kinases.

    Science.gov (United States)

    Bury, Marina; Andolfi, Anna; Rogister, Bernard; Cimmino, Alessio; Mégalizzi, Véronique; Mathieu, Véronique; Feron, Olivier; Evidente, Antonio; Kiss, Robert

    2013-04-01

    Glioblastoma multiforme (GBM) is a deadly cancer that possesses an intrinsic resistance to pro-apoptotic insults, such as conventional chemotherapy and radiotherapy, and diffusely invades the brain parenchyma, which renders it elusive to total surgical resection. We found that fusicoccin A, a fungal metabolite from Fusicoccum amygdali, decreased the proliferation and migration of human GBM cell lines in vitro, including several cell lines that exhibit varying degrees of resistance to pro-apoptotic stimuli. The data demonstrate that fusicoccin A inhibits GBM cell proliferation by decreasing growth rates and increasing the duration of cell division and also decreases two-dimensional (measured by quantitative video microscopy) and three-dimensional (measured by Boyden chamber assays) migration. These effects of fusicoccin A treatment translated into structural changes in actin cytoskeletal organization and a loss of GBM cell adhesion. Therefore, fusicoccin A exerts cytostatic effects but low cytotoxic effects (as demonstrated by flow cytometry). These cytostatic effects can partly be explained by the fact that fusicoccin inhibits the activities of a dozen kinases, including focal adhesion kinase (FAK), that have been implicated in cell proliferation and migration. Overexpression of FAK, a nonreceptor protein tyrosine kinase, directly correlates with the invasive phenotype of aggressive human gliomas because FAK promotes cell proliferation and migration. Fusicoccin A led to the down-regulation of FAK tyrosine phosphorylation, which occurred in both normoxic and hypoxic GBM cell culture conditions. In conclusion, the current study identifies a novel compound that could be used as a chemical template for generating cytostatic compounds designed to combat GBM.

  6. Phosphoproteome Reveals an Atlas of Protein Signaling Networks During Osteoblast Adhesion

    NARCIS (Netherlands)

    Milani, Renato; Ferreira, Carmen V.; Granjeiro, Jose M.; Paredes-Gamero, Edgar J.; Silva, Rodrigo A.; Justo, Giselle Z.; Nader, Helena B.; Galembeck, Eduardo; Peppelenbosch, Maikel P.; Aoyama, Hiroshi; Zambuzzi, Willian F.

    2010-01-01

    Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important r

  7. Adhesive tape exfoliation

    DEFF Research Database (Denmark)

    Bohr, Jakob

    2015-01-01

    cleaving of a single chunk of graphite. For both cases, parallel and serial exfoliation, it is investigated how many generations of cleavages are needed. An approximate model with the probability distribution expressed as a simple closed form is presented and compared with the simulations.......Single-crystal graphite can be cleaved by the use of an adhesive tape. This was also the initial route for obtaining graphene, a one-layer thick graphite slab. In this letter a few simple and fun considerations are presented in an attempt to shed some light on why this procedure is successful...

  8. [Adhesive cutaneous pharmaceutical forms].

    Science.gov (United States)

    Gafiţanu, E; Matei, I; Mungiu, O C; Pavelescu, M; Mîndreci, I; Apostol, I; Ionescu, G

    1989-01-01

    The adhesive cutaneous pharmaceutical forms aimed to local action release the drug substance in view of a dermatological, traumatological, antirheumatic, cosmetic action. Two such preparations were obtained and their stability, consistency and pH were determined. The "in vitro" tests of their bioavailability revealed the dynamics of calcium ions release according to the associations of each preparation. The bioavailability determined by evaluating the pharmacological response demonstrated the antiinflammatory action obtained by the association of calcium ions with the components extracted from poplar muds. The therapeutical efficiency of the studied preparations has proved in the treatment of some sport injuries.

  9. Syndecan proteoglycans and cell adhesion

    DEFF Research Database (Denmark)

    Woods, A; Oh, E S; Couchman, J R

    1998-01-01

    It is now becoming clear that a family of transmembrane proteoglycans, the syndecans, have important roles in cell adhesion. They participate through binding of matrix ligand to their glycosaminoglycan chains, clustering, and the induction of signaling cascades to modify the internal microfilament...... organization. Syndecans can modulate the type of adhesive responses induced by other matrix ligand-receptor interactions, such as those involving the integrins, and so contribute to the control of cell morphology, adhesion and migration....

  10. Adhesion properties of gecko setae

    Science.gov (United States)

    Hill, Ginel; Peattie, Anne; Daniels, Roxanne; Full, Robert; Kenny, Thomas

    2005-03-01

    Millions of keratin hairs on gecko feet, called setae, act as a spectacular dry adhesive. Each seta branches into hundreds of smaller fibers that terminate in spatula-shaped ends. Morphological differences between the setae from different gecko species are suspected to affect both single-seta and whole-animal adhesion properties. Single-seta adhesive force measurements made using a MEMS piezoresistive cantilever capable of two-axis measurements are presented.

  11. pH Responsive and Oxidation Resistant Wet Adhesive based on Reversible Catechol-Boronate Complexation.

    Science.gov (United States)

    Narkar, Ameya R; Barker, Brett; Clisch, Matthew; Jiang, Jingfeng; Lee, Bruce P

    2016-08-09

    A smart adhesive capable of binding to a wetted surface was prepared by copolymerizing dopamine methacrylamide (DMA) and 3-acrylamido phenylboronic acid (AAPBA). pH was used to control the oxidation state and the adhesive property of the catechol side chain of DMA and to trigger the catechol-boronate complexation. FTIR spectroscopy confirmed the formation of the complex at pH 9, which was not present at pH 3. The formation of the catechol-boronate complex increased the cross-linking density of the adhesive network. Most notably, the loss modulus values of the adhesive were more than an order of magnitude higher for adhesive incubated at pH 9 when compared to those measured at pH 3. This drastic increase in the viscous dissipation property is attributed to the introduction of reversible complexation into the adhesive network. Based on the Johnson Kendall Roberts (JKR) contact mechanics test, adhesive containing both DMA and AAPBA demonstrated strong interfacial binding properties (work of adhesion (Wadh) = 2000 mJ/m(2)) to borosilicate glass wetted with an acidic solution (pH 3). When the pH was increased to 9, Wadh values (180 mJ/m(2)) decreased by more than an order of magnitude. During successive contact cycles, the adhesive demonstrated the capability to transition reversibly between its adhesive and nonadhesive states with changing pH. Adhesive containing only DMA responded slowly to repeated changes in pH and became progressively oxidized without the protection of boronic acid. Although adhesive containing only AAPBA also demonstrated strong wet adhesion (Wadh ∼ 500 mJ/m(2)), its adhesive properties were not pH responsive. Both DMA and AAPBA are required to fabricate a smart adhesive with tunable and reversible adhesive properties.

  12. Coordinated cell motility is regulated by a combination of LKB1 farnesylation and kinase activity

    Science.gov (United States)

    Wilkinson, S.; Hou, Y.; Zoine, J. T.; Saltz, J.; Zhang, C.; Chen, Z.; Cooper, L. A. D.; Marcus, A. I.

    2017-01-01

    Cell motility requires the precise coordination of cell polarization, lamellipodia formation, adhesion, and force generation. LKB1 is a multi-functional serine/threonine kinase that associates with actin at the cellular leading edge of motile cells and suppresses FAK. We sought to understand how LKB1 coordinates these multiple events by systematically dissecting LKB1 protein domain function in combination with live cell imaging and computational approaches. We show that LKB1-actin colocalization is dependent upon LKB1 farnesylation leading to RhoA-ROCK-mediated stress fiber formation, but membrane dynamics is reliant on LKB1 kinase activity. We propose that LKB1 kinase activity controls membrane dynamics through FAK since loss of LKB1 kinase activity results in morphologically defective nascent adhesion sites. In contrast, defective farnesylation mislocalizes nascent adhesion sites, suggesting that LKB1 farnesylation serves as a targeting mechanism for properly localizing adhesion sites during cell motility. Together, we propose a model where coordination of LKB1 farnesylation and kinase activity serve as a multi-step mechanism to coordinate cell motility during migration. PMID:28102310

  13. The neural cell adhesion molecule

    DEFF Research Database (Denmark)

    Berezin, V; Bock, E; Poulsen, F M

    2000-01-01

    During the past year, the understanding of the structure and function of neural cell adhesion has advanced considerably. The three-dimensional structures of several of the individual modules of the neural cell adhesion molecule (NCAM) have been determined, as well as the structure of the complex...... between two identical fragments of the NCAM. Also during the past year, a link between homophilic cell adhesion and several signal transduction pathways has been proposed, connecting the event of cell surface adhesion to cellular responses such as neurite outgrowth. Finally, the stimulation of neurite...

  14. A gecko-inspired double-sided adhesive.

    Science.gov (United States)

    Wang, Zhengzhi; Gu, Ping; Wu, Xiaoping

    2013-12-21

    Geckos' outstanding abilities to adhere to various surfaces are widely credited to the large actual contact areas of the fibrillar and hierarchical structures on their feet. These special features regulate the essential structural compliance for every attachment and thus provide robust yet reversible adhesions. Inspired by gecko's feet and our commonly used double-faced tape, we have successfully fabricated a gecko-inspired double-sided dry adhesive by using porous anodic alumina template assisted nano-wetting on a stiff polymer. It was determined that the obtained 2-sided structure showed largely decreased effective stiffness compared with its 1-sided counterpart, which favored better compliance and interfacial integrity. We also demonstrated that the repeatable double-sided adhesive improved the macroscopic normal and shear adhesion capacities over the widely-studied 1-side structure by ~50% and ~85%, respectively. By using the synthetic double-sided adhesive, the usage of traditional pressure-sensitive/chemical adhesives could be well avoided. Besides, the double-sided nanostructures showed great potential in finding new interesting properties and practical applications for the synthetic dry adhesives.

  15. Hydrolytic stability of self-etch adhesives bonded to dentin.

    Science.gov (United States)

    Inoue, S; Koshiro, K; Yoshida, Y; De Munck, J; Nagakane, K; Suzuki, K; Sano, H; Van Meerbeek, B

    2005-12-01

    Functional monomers chemically interact with hydroxyapatite that remains within submicron hybrid layers produced by mild self-etch adhesives. The functional monomer 10-MDP interacts most intensively with hydroxyapatite, and its calcium salt appeared most hydrolytically stable, as compared with 4-MET and phenyl-P. We investigated the hypothesis that additional chemical interaction of self-etch adhesives improves bond stability. The micro-tensile bond strength (muTBS) of the 10-MDP-based adhesive did not decrease significantly after 100,000 cycles, but did after 50,000 and 30,000 cycles, respectively, for the 4-MET-based and the phenyl-P-based adhesives. Likewise, the interfacial ultrastructure was unchanged after 100,000 thermocycles for the 10-MDP-based adhesive, while that of both the 4-MET- and phenyl-P-based adhesives contained voids and less-defined collagen. The findings of this study support the concept that long-term durability of adhesive-dentin bonds depends on the chemical bonding potential of the functional monomer.

  16. Three functions of cadherins in cell adhesion.

    Science.gov (United States)

    Maître, Jean-Léon; Heisenberg, Carl-Philipp

    2013-07-22

    Cadherins are transmembrane proteins that mediate cell-cell adhesion in animals. By regulating contact formation and stability, cadherins play a crucial role in tissue morphogenesis and homeostasis. Here, we review the three major functions of cadherins in cell-cell contact formation and stability. Two of those functions lead to a decrease in interfacial tension at the forming cell-cell contact, thereby promoting contact expansion--first, by providing adhesion tension that lowers interfacial tension at the cell-cell contact, and second, by signaling to the actomyosin cytoskeleton in order to reduce cortex tension and thus interfacial tension at the contact. The third function of cadherins in cell-cell contact formation is to stabilize the contact by resisting mechanical forces that pull on the contact.

  17. Pressure sensitive adhesives from renewable resources

    OpenAIRE

    Maaßen, Wiebke

    2015-01-01

    Pressure-sensitive adhesives (PSAs) represent an important segment of the adhesives market. In this work, novel insights into the adhesive performance of bio-based pressure sensitive adhesives are presented. Three different homopolymers based on fatty acids derived from native vegetable oils as renewable feedstock were characterized in terms of their mechanical and adhesive properties.

  18. Stretchable, adhesion-tunable dry adhesive by surface wrinkling.

    Science.gov (United States)

    Jeong, Hoon Eui; Kwak, Moon Kyu; Suh, Kahp Y

    2010-02-16

    We introduce a simple yet robust method of fabricating a stretchable, adhesion-tunable dry adhesive by combining replica molding and surface wrinkling. By utilizing a thin, wrinkled polydimethyl siloxane (PDMS) sheet with a thickness of 1 mm with built-in micropillars, active, dynamic control of normal and shear adhesion was achieved. Relatively strong normal (approximately 10.8 N/cm(2)) and shear adhesion (approximately 14.7 N/cm(2)) forces could be obtained for a fully extended (strained) PDMS sheet (prestrain of approximately 3%), whereas the forces could be rapidly reduced to nearly zero once the prestrain was released (prestrain of approximately 0.5%). Moreover, durability tests demonstrated that the adhesion strength in both the normal and shear directions was maintained over more than 100 cycles of attachment and detachment.

  19. Effect of adhesive thickness on adhesively bonded T-joint

    Science.gov (United States)

    Abdullah, A. R.; Afendi, Mohd; Majid, M. S. Abdul

    2013-12-01

    The aim of this work is to analyze the effect of adhesive thickness on tensile strength of adhesively bonded stainless steel T-joint. Specimens were made from SUS 304 Stainless Steel plate and SUS 304 Stainless Steel perforated plate. Four T-joint specimens with different adhesive thicknesses (0.5, 1.0, 1.5 and 2.0 mm) were made. Experiment result shows T-joint specimen with adhesive thickness of 1.0 mm yield highest maximum load. Identical T-joint specimen jointed by spot welding was also tested. Tensile test shows welded T-Joint had eight times higher tensile load than adhesively bonded T-joint. However, in low pressure application such as urea granulator chamber, high tensile strength is not mandatory. This work is useful for designer in fertilizer industry and others who are searching for alternative to spot welding.

  20. Stretchable, Adhesion-Tunable Dry Adhesive by Surface Wrinkling

    KAUST Repository

    Jeong, Hoon Eui

    2010-02-16

    We introduce a simple yet robust method of fabricating a stretchable, adhesion-tunable dry adhesive by combining replica molding and surface wrinkling. By utilizing a thin, wrinkled polydimethyl siloxane (PDMS) sheet with a thickness of 1 mm with built-in micropillars, active, dynamic control of normal and shear adhesion was achieved. Relatively strong normal (∼10.8 N/cm2) and shear adhesion (∼14.7 N/cm2) forces could be obtained for a fully extended (strained) PDMS sheet (prestrain of∼3%), whereas the forces could be rapidly reduced to nearly zero once the prestrain was released (prestrain of ∼0.5%). Moreover, durability tests demonstrated that the adhesion strength in both the normal and shear directions was maintained over more than 100 cycles of attachment and detachment. © 2010 American Chemical Society.

  1. Improved Adhesion and Compliancy of Hierarchical Fibrillar Adhesives.

    Science.gov (United States)

    Li, Yasong; Gates, Byron D; Menon, Carlo

    2015-08-01

    The gecko relies on van der Waals forces to cling onto surfaces with a variety of topography and composition. The hierarchical fibrillar structures on their climbing feet, ranging from mesoscale to nanoscale, are hypothesized to be key elements for the animal to conquer both smooth and rough surfaces. An epoxy-based artificial hierarchical fibrillar adhesive was prepared to study the influence of the hierarchical structures on the properties of a dry adhesive. The presented experiments highlight the advantages of a hierarchical structure despite a reduction of overall density and aspect ratio of nanofibrils. In contrast to an adhesive containing only nanometer-size fibrils, the hierarchical fibrillar adhesives exhibited a higher adhesion force and better compliancy when tested on an identical substrate.

  2. Cooperative inhibitory effects of antisense oligonucleotide of cell adhesion molecules and cimetidine on cancer cell adhesion

    Institute of Scientific and Technical Information of China (English)

    Nan-Hong Tang; Yan-Ling Chen; Xiao-Qian Wang; Xiu-Jin Li; Feng-Zhi Yin; Xiao-Zhong Wang

    2004-01-01

    AIM: To explore the cooperative effects of antisense oligonucleotide (ASON) of cell adhesion molecules and cimetidine on the expression of E-selectin and ICAM-1 in endothelial cells and their adhesion to tumor cells.METHODS: After treatment of endothelial cells with ASON and/or cimetidine and induction with TNF-α, the protein and mRNA changes of E-selectin and ICAM-1 in endothelial cells were examined by flow cytometry and RT-PCR,respectively. The adhesion rates of endothelial cells to tumor cells were measured by cell adhesion experiment.RESULTS: In comparison with TNF-α inducing group, lipoASON and lipo-ASON/cimetidine could significantly decrease the protein and mRNA levels of E-selectin and ICAM-1 in endothelial cells, and lipo-ASON/cimetidine had most significant inhibitory effect on E-selectin expression (from 36.37±1.56% to 14.23±1.07%, P<0.001). Meanwhile,cimetidine alone could inhibit the expression of E-selectin (36.37±1.56% vs 27.2±1.31%, P<0.001), but not ICAM-1 (69.34±2.50% vs68.07±2.10%,P>O.05)and the two kinds of mRNA, either. Compared with TNF-αα inducing group, the rate of adhesion was markedly decreased in lipo-E-selectin ASON and lipo-E-selectin ASON/cimetidine treated groups(P<0.05),and Jipo-E-selectin ASON/cimetidine worked better than lipo-E-selectin ASON alone except for HepG2/ECV304 group(P<0.05). However, the decrease of adhesion was not significant in lipo-ICAM-1 ASON and lipo-ICAM-1 ASON/cimetidine treated groups except for HepG2/ECV304 group (P >0.05).CONCLUSION: These data demonstrate that ASON in combination with cimetidine in vitro can significantly reduce the adhesion between endothelial cells and hepatic or colorectal cancer cells, which is stronger than ASON or cimetidine alone. This study provides some useful proofs for gene therapy of antiadhesion.

  3. Studying Kinetochore Kinases

    NARCIS (Netherlands)

    Saurin, Adrian T; Kops, Geert J P L

    2016-01-01

    Mitotic kinetochores are signaling network hubs that regulate chromosome movements, attachment error-correction, and the spindle assembly checkpoint. Key switches in these networks are kinases and phosphatases that enable rapid responses to changing conditions. Describing the mechanisms and dynamics

  4. Cleaning properties of dry adhesives

    Institute of Scientific and Technical Information of China (English)

    J.; P.; DíAZ; TéLLEZ; D.; SAMEOTO; C.; MENON

    2010-01-01

    In this paper we present a study into the cleaning properties of synthetic dry adhesives. We have manufactured the adhesive micro-fibres through a low-cost, high yield fabrication method using Sylgard 184 Polydimethylsiloxane (PDMS) as the structural material. We deliberately contaminated the adhesive samples with different sized particles in the micro and macro scales and tested different cleaning methods for their efficacy with respect to each particle size. We investigated different cleaning methods, which included the use of wax moulding, vibration and pressure sensitive adhesives. For adhesion testing we used a custom system with a linear stage and a force sensor indenting a hemispherical probe into the adhesive surface and measuring the pull-off force. To characterize the cleaning efficacy we visually inspected each sample in a microscope and weighed the samples with a microgram-accuracy analytical balance. Results showed that the moulding method induced adhesion recovery in a greater percentage than the other cleaning methods and even helped with the recovery of collapsed posts in some cases. On the other hand pressure sensitive adhesives seem to have the upper hand with regards to certain particle sizes that can potentially pose problems with the moulding method.

  5. 21 CFR 880.5240 - Medical adhesive tape and adhesive bandage.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Medical adhesive tape and adhesive bandage. 880... Personal Use Therapeutic Devices § 880.5240 Medical adhesive tape and adhesive bandage. (a) Identification. A medical adhesive tape or adhesive bandage is a device intended for medical purposes that...

  6. Comparative evaluation of tensile bond strengths of total-etch adhesives and self-etch adhesives with single and multiple consecutive applications: An in vitro study

    Directory of Open Access Journals (Sweden)

    Mandava Deepthi

    2009-01-01

    Full Text Available Aim: This study evaluates the effect of single and multiple consecutive applications of adhesives on the tensile bond strength. The currently available adhesives follow either the total-etch or the self-etch concept. However, in both techniques the uniformity and thickness of the adhesive layer plays a significant role in the development of a good bond. Materials and Methods: Sixty composite-dentin bonded specimens were prepared using a total-etch adhesive (Gluma and another 60 using a self-etch adhesive (AdheSE. Each group was further divided into six subgroups based on the number of applications, i.e., single application and multiple (2, 3, 4, 6, and 8 applications. The tensile bond strength was tested with the Instron universal testing machine. The values were analyzed with one-way ANOVA and multiple range tests by Tukey′s HSD procedure to identify those subgroups that had significantly higher bond strength. Results: The results indicate that with total-etch adhesive the bond strength increases significantly as the number of applications are increased from one to two or from two to three", for self-etch adhesive the bond strength obtained with two applications is significantly higher than that with one application. However, for both adhesive systems, there was a decrease in the tensile bond strength values with further applications. Conclusion: We conclude that, in the clinical setting, the application of multiple coats of total etch adhesive improves bonding.

  7. Decreasing relative risk premium

    DEFF Research Database (Denmark)

    Hansen, Frank

    2007-01-01

    such that the corresponding relative risk premium is a decreasing function of present wealth, and we determine the set of associated utility functions. We find a new characterization of risk vulnerability and determine a large set of utility functions, closed under summation and composition, which are both risk vulnerable...... and have decreasing relative risk premium. We finally introduce the notion of partial risk neutral preferences on binary lotteries and show that partial risk neutrality is equivalent to preferences with decreasing relative risk premium...

  8. Shear lag sutures: Improved suture repair through the use of adhesives.

    Science.gov (United States)

    Linderman, Stephen W; Kormpakis, Ioannis; Gelberman, Richard H; Birman, Victor; Wegst, Ulrike G K; Genin, Guy M; Thomopoulos, Stavros

    2015-09-01

    Suture materials and surgical knot tying techniques have improved dramatically since their first use over five millennia ago. However, the approach remains limited by the ability of the suture to transfer load to tissue at suture anchor points. Here, we predict that adhesive-coated sutures can improve mechanical load transfer beyond the range of performance of existing suture methods, thereby strengthening repairs and decreasing the risk of failure. The mechanical properties of suitable adhesives were identified using a shear lag model. Examination of the design space for an optimal adhesive demonstrated requirements for strong adhesion and low stiffness to maximize the strength of the adhesive-coated suture repair construct. To experimentally assess the model, we evaluated single strands of sutures coated with highly flexible cyanoacrylates (Loctite 4903 and 4902), cyanoacrylate (Loctite QuickTite Instant Adhesive Gel), rubber cement, rubber/gasket adhesive (1300 Scotch-Weld Neoprene High Performance Rubber & Gasket Adhesive), an albumin-glutaraldehyde adhesive (BioGlue), or poly(dopamine). As a clinically relevant proof-of-concept, cyanoacrylate-coated sutures were then used to perform a clinically relevant flexor digitorum tendon repair in cadaver tissue. The repair performed with adhesive-coated suture had significantly higher strength compared to the standard repair without adhesive. Notably, cyanoacrylate provides strong adhesion with high stiffness and brittle behavior, and is therefore not an ideal adhesive for enhancing suture repair. Nevertheless, the improvement in repair properties in a clinically relevant setting, even using a non-ideal adhesive, demonstrates the potential for the proposed approach to improve outcomes for treatments requiring suture fixation. Further study is necessary to develop a strongly adherent, compliant adhesive within the optimal design space described by the model.

  9. Soy protein isolate molecular level contributions to bulk adhesive properties

    Science.gov (United States)

    Shera, Jeanne Norton

    Increasing environmental awareness and the recognized health hazards of formaldehyde-based resins has prompted a strong demand for environmentally-responsible adhesives for wood composites. Soy protein-based adhesives have been shown to be commercially viable with 90-day shelf stability and composite physical properties comparable to those of commercial formaldehyde-based particleboards. The main research focus is to isolate and characterize the molecular level features in soy protein isolate responsible for providing mechanical properties, storage stability, and water resistance during adhesive formulation, processing, and wood composite fabrication. Commercial composite board will be reviewed to enhance our understanding of the individual components and processes required for particleboard production. The levels of protein structure will be defined and an overview of current bio-based technology will be presented. In the process, the logic for utilizing soy protein as a sole binder in the adhesive will be reinforced. Variables such as adhesive components, pH, divalent ions, blend aging, protein molecular weight, formulation solids content, and soy protein functionalization will relate the bulk properties of soy protein adhesives to the molecular configuration of the soybean protein. This work has demonstrated that when intermolecular beta-sheet interactions and protein long-range order is disrupted, viscosity and mechanical properties decrease. Storage stability can be maintained through the stabilization of intermolecular beta-sheet interactions. When molecular weight is reduced through enzymatic digestion, long-range order is disrupted and viscosity and mechanical properties decrease accordingly. Processibility and physical properties must be balanced to increase solids while maintaining low viscosity, desirable mechanical properties, and adequate storage stability. The structure of the soybean protein must be related to the particleboard bulk mechanical

  10. Interfacial adhesion for microelectronics and MEMS devices

    Science.gov (United States)

    Kennedy, Marian Siobhan

    2007-12-01

    The reliability of thin film systems is important to the continued development of microelectronic and micro-electro-mechanical systems. Most often, reliability of these systems is tied to the ability of the films to remain adhered to its substrate. By measuring the amount of energy to separate the film, interfacial fracture energy, and prediciting trends researchers can predicts film lifetimes. Recent work to measure this energy has resulted in several different testing techniques including spontaneous buckling, indentation induced delamination and four point bending. Literature has shown good agreement between delamination test methods, but only when energy dissipation into the substrate is minimized. Using a W/Si system, the effect of energy dissipation was shown to decrease from 0.6 J/m2 to 0.2 J/m2 between different methods; one where the only fracture was along the interface and the other where cracking also occurred in the film and substrate. For systems where fracture only occurs along the interface, such as Au/Si, the calculated fracture energies are identical if the energy put into the system is kept near the needed strain energy to cause delamination. Overlayers of different stresses and thickness on Au/Si showed that the adhesion energies could change by a factor of three (Chapter 3). This dependence on applied energy is also shown when comparisons of four point bending and stressed overlayer test methods were completed on Pt/Si systems. The fracture energies of Pt/Ti/SiO2 were studied using four-point bending and compressive overlayers. Varying the thickness of the Ti film from 2 to 17 nm in a Pt/Ti/SiO2 system, both test methods showed an increase of adhesion energy until the nominal Ti thickness was 12nm. Then this adhesion energy began to decrease. This decrease was due to an increase in the Pt grain size after a nominal 12nm thickness (Chapter 4 and 5). While the trends in energy release rate are similar, the magnitude of the toughness between the

  11. Molecular mechanisms underlying synergistic adhesion of sickle red blood cells by hypoxia and low nitric oxide bioavailability.

    Science.gov (United States)

    Gutsaeva, Diana R; Montero-Huerta, Pedro; Parkerson, James B; Yerigenahally, Shobha D; Ikuta, Tohru; Head, C Alvin

    2014-03-20

    The molecular mechanisms by which nitric oxide (NO) bioavailability modulates the clinical expression of sickle cell disease (SCD) remain elusive. We investigated the effect of hypoxia and NO bioavailability on sickle red blood cell (sRBC) adhesion using mice deficient for endothelial NO synthase (eNOS) because their NO metabolite levels are similar to those of SCD mice but without hypoxemia. Whereas sRBC adhesion to endothelial cells in eNOS-deficient mice was synergistically upregulated at the onset of hypoxia, leukocyte adhesion was unaffected. Restoring NO metabolite levels to physiological levels markedly reduced sRBC adhesion to levels seen under normoxia. These results indicate that sRBC adherence to endothelial cells increases in response to hypoxia prior to leukocyte adherence, and that low NO bioavailability synergistically upregulates sRBC adhesion under hypoxia. Although multiple adhesion molecules mediate sRBC adhesion, we found a central role for P-selectin in sRBC adhesion. Hypoxia and low NO bioavailability upregulated P-selectin expression in endothelial cells in an additive manner through p38 kinase pathways. These results demonstrate novel cellular and signaling mechanisms that regulate sRBC adhesion under hypoxia and low NO bioavailability. Importantly, these findings point us toward new molecular targets to inhibit cell adhesion in SCD.

  12. Translucent titanium coating altered the composition of focal adhesions and promoted migration of osteoblast-like MG-63 cells on glass.

    Science.gov (United States)

    Ho, Yi; Kok, Sang-Heng; Wang, Juo-Song; Lin, Li-Deh

    2014-04-01

    "TiGlass" was designed and was known to promote initial adhesion and increase migration of rat calvarial osteoblats. In this article, migration study and a series of epifluorescence microscopic studies were conducted to find out the composition of focal adhesion on titanium surface. The translucent titanium surface was applied in random migration analysis and immunofluorescence cell staining. In the immunofluorescent double staining, phosphorylated focal adhesion kinase was tested with vinculin. Various integrin subunits were then tested with vinculin to study the composition of activated focal adhesions. Integrin subunit α5 and αV were tested against β3; integrin subunits α5, αV, β3, and αVβ3 were tested with F-actin, respectively. The MG-63 cells began migration earlier and migrated faster on "TiGlass." Immunofluorescent double staining revealed that all focal adhesion kinase in the focal adhesions were activated on both the surfaces. The osteoblast was inferred to made adhesion to titanium and glass through integrins. The focal adhesions on glass were found to be composed of integrin subunits αV and β3. However, on "TiGlass," integrin subunits α5 might have supplemented the adhesion to titanium. Results from double staining of integrin subunits α5, αV, β3, and αVβ3 with F-actin also supported integrin subunits α5 might have involved in adhesion of titanium.

  13. Universal adhesives: the next evolution in adhesive dentistry?

    Science.gov (United States)

    Alex, Gary

    2015-01-01

    Every so often a new material, technique, or technological breakthrough spurs a paradigm shift in the way dentistry is practiced. The development and evolution of reliable enamel and dentin bonding agents is one such example. Indeed, the so-called "cosmetic revolution" in dentistry blossomed in large part due to dramatic advances in adhesive technology. It is the ability to bond various materials in a reasonably predictable fashion to both enamel and dentin substrates that enables dentists to routinely place porcelain veneers, direct and indirect composites, and a plethora of other restorative and esthetic materials. In fact, the longevity and predictability of many (if not most) current restorative procedures is wholly predicated on the dentist's ability to bond various materials to tooth tissues. Adhesive systems have progressed from the largely ineffective systems of the 1970s and early 1980s to the relatively successful total- and self-etching systems of today. The latest players in the adhesive marketplace are the so-called "universal adhesives." In theory, these systems have the potential to significantly simplify and expedite adhesive protocols and may indeed represent the next evolution in adhesive dentistry. But what defines a universal system, and are all these new systems truly "universal" and everything they are claimed to be? This article will examine the origin, chemistry, strengths, weaknesses, and clinical relevance of this new genre of dental adhesives.

  14. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion.

    Directory of Open Access Journals (Sweden)

    Wagner Shin Nishitani

    Full Text Available A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7 expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion.

  15. Rapid and Localized Mechanical Stimulation and Adhesion Assay: TRPM7 Involvement in Calcium Signaling and Cell Adhesion.

    Science.gov (United States)

    Nishitani, Wagner Shin; Alencar, Adriano Mesquita; Wang, Yingxiao

    2015-01-01

    A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs) in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7) expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount) and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment) and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion.

  16. Effect of H2O2,extracellular matrix and out segment of photoreceptor on expression of focal adhesion kinase in RPE cell%氧化衰老、细胞外基质和光感受器外节膜盘对RPE细胞中黏着斑激酶表达的影响

    Institute of Scientific and Technical Information of China (English)

    朱洁; 王雨生; 赵炜; 杨秀梅; 李夏; 姜廷帅

    2011-01-01

    Background The underlying mechanism of choroidal neovascularization(CNV) is multifactorial and complex.Focal adhesion kinase(FAK) plays a crucial role in controlling essential cellular processes and influencing distinct steps of the angiogenic response.But to our knowledge,seldom study on the effect of FAK on CNV formation has been reported previously.Objective In this study,the effect of several CNV risk factors on the expression of FAK in cultured retinal pigment epithelium(RPE) cells was investigated to illuminate effect of FAK on CNV.Methods Human RPE cells were isolated from donor eyes and exposed to H2O2,swallow of outer segment of photoreceptors(POS) and extracellular matrix(ECM) separately with the treating as follows:RPE cells were co-cultured with 10,20,50 and 100μmol/L H2O2 for 20 days;POS(1×106/ml) were co-cultivated with RPE cells for 20 days(setting control group,POS group,hypoxia group with 200μmol/L CoCl2,and POS+hyoxia group);RPE cells were cultured on the plates coated with 100mg/L fibronectin(FN),laminin(LN) or collagen typeⅠfor 30minutes or 1 hour.The expression of FAK and pFAK in RPE cells were examined by Western blot analysis.Results FAK was highly expressed in the 20μmol/L and 50μmol/L H2O2 groups compared with control group(P<0.01);while he expression level of pFAK was reduced after treated with H2O2 in comparison with the control group(P<0.01).After cultured with POS for 20 days,the undigested lysosome could be observed in RPE cells.The expressions of FAK and pFAK in RPE cells were not significantly changed between control group and POS groups(P>0.05),but those in hypoxia group were significantly up-regulated in comparison with control group(P<0.01).Compared with the hypoxia group,the expression amount of pFAK was elevated in POS+hyoxia group(P<0.01).In comparison with control group,the increased pFAK expression was seen in FN,LN and collagen typeⅠtreating for 1-hour groups(P<0.05,P<0.01).Conclusion FAK pathway

  17. 烟酸对p38丝裂原活化蛋白激酶信号通路介导的内皮细胞功能障碍的早期干预研究%Effects of niacin on cell adhesion and early atherogenesis:involvement of the p38 mitogen-activated protein kinases pathway

    Institute of Scientific and Technical Information of China (English)

    牛娜; 韩波; 孙书珍; 于永慧; 汪翼; 王立俊

    2013-01-01

    制有待进一步研究.%Objective To examine the effects of niacin on lysophosphatidylcholine (LPC)-induced intercellular adhesion molecule-1 (ICAM-1),and gained insight to the mechanisms.Method Human umbilical vein endothelial cell line was cultured using Medium 200 medium in incubator at 37 ℃ and 5% CO2 condition.Experimental groups:(1) the negative control group:medium; (2) LPC different time groups:the medium added with 20 μmol/L final concentration of LPC,were cultured for 10 min and 8 h,24 h; (3) LPC + p38-mitogen-activated protein kinase (p38MAPK) inhibitor (SB203580) group:the medium added with 10 μmol/L p38MAPK inhibitor (SB203580) was cultured for 1 h,then human umbilical vein endothelial cells (HUVECs) added with the LPC were cultured for 10 min,8 h and 24 h.(4) LPC + different niacin dose group:after separately adding with 0.25,0.5,1 mmol/L niacin,the cells were cultured for 18 h,then HUVECs added with the LPC were cultured for 10 min,8 h and 24 h.Cell concentration in each group was 5 × 105/ml,inoculated in 6-well plates,each well 1 ml.Detected by Western blot analysis of pp38MAPK,ICAM-1 protein content,real-time quantitative PCR to detect endothelial cell ICAM-1 mRNA expression,cell immunofluorescence to detect LPC-induced ICAM-1 protein expression.Result In LPC 24 h group,the expression of ICAM-1 protein was significantly increased 0.786 ± 0.02,the LPC + niacin group,ICAM-1 protein levels (0.487 ±0.015) was significantly lower than the LPC 24 h group (P <0.01),in LPC + SB203580 intervention group,ICAM-1 protein levels (0.461 ± 0.011) was significantly lower than that of the LPC 24 h group (P < 0.01),but did not reach the level of the control group.Adding LPC to culture for 10 min,phosphorylation of p38MAPK (pp38MAPK) reached its peak (0.47 ± 0.02),niacin could reduce the pp38MAPK (0.07 ± 0.02),SB203580 could also reduce its activity (0.11 ± 0.02).Adding LPC to culture for 8 h,ICAM-1 mRNA expression (8.16 ± 0.15) compared with the control group (1.00 ± 0.02) had a

  18. Glycogen Synthase Kinase 3 (GSK-3) influences epithelial barrier function by regulating Occludin, Claudin-1 and E-cadherin expression

    Energy Technology Data Exchange (ETDEWEB)

    Severson, Eric A.; Kwon, Mike; Hilgarth, Roland S.; Parkos, Charles A. [Epithelial Pathobiology Research Unit, Dept. of Pathology, Emory University, Atlanta, GA 30322 (United States); Nusrat, Asma, E-mail: anusrat@emory.edu [Epithelial Pathobiology Research Unit, Dept. of Pathology, Emory University, Atlanta, GA 30322 (United States)

    2010-07-02

    The Apical Junctional Complex (AJC) encompassing the tight junction (TJ) and adherens junction (AJ) plays a pivotal role in regulating epithelial barrier function and epithelial cell proliferative processes through signaling events that remain poorly characterized. A potential regulator of AJC protein expression is Glycogen Synthase Kinase-3 (GSK-3). GSK-3 is a constitutively active kinase that is repressed during epithelial-mesenchymal transition (EMT). In the present study, we report that GSK-3 activity regulates the structure and function of the AJC in polarized model intestinal (SK-CO15) and kidney (Madin-Darby Canine Kidney (MDCK)) epithelial cells. Reduction of GSK-3 activity, either by small molecule inhibitors or siRNA targeting GSK-3 alpha and beta mRNA, resulted in increased permeability to both ions and bulk solutes. Immunofluorescence labeling and immunoblot analyses revealed that the barrier defects correlated with decreased protein expression of AJC transmembrane proteins Occludin, Claudin-1 and E-cadherin without influencing other TJ proteins, Zonula Occludens-1 (ZO-1) and Junctional Adhesion Molecule A (JAM-A). The decrease in Occludin and E-cadherin protein expression correlated with downregulation of the corresponding mRNA levels for these respective proteins following GSK-3 inhibition. These observations implicate an important role of GSK-3 in the regulation of the structure and function of the AJC that is mediated by differential modulation of mRNA transcription of key AJC proteins, Occludin, Claudin-1 and E-cadherin.

  19. Cell adhesion during bullet motion in capillaries.

    Science.gov (United States)

    Takeishi, Naoki; Imai, Yohsuke; Ishida, Shunichi; Omori, Toshihiro; Kamm, Roger D; Ishikawa, Takuji

    2016-08-01

    A numerical analysis is presented of cell adhesion in capillaries whose diameter is comparable to or smaller than that of the cell. In contrast to a large number of previous efforts on leukocyte and tumor cell rolling, much is still unknown about cell motion in capillaries. The solid and fluid mechanics of a cell in flow was coupled with a slip bond model of ligand-receptor interactions. When the size of a capillary was reduced, the cell always transitioned to "bullet-like" motion, with a consequent decrease in the velocity of the cell. A state diagram was obtained for various values of capillary diameter and receptor density. We found that bullet motion enables firm adhesion of a cell to the capillary wall even for a weak ligand-receptor binding. We also quantified effects of various parameters, including the dissociation rate constant, the spring constant, and the reactive compliance on the characteristics of cell motion. Our results suggest that even under the interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin, which is mainly responsible for leukocyte rolling, a cell is able to show firm adhesion in a small capillary. These findings may help in understanding such phenomena as leukocyte plugging and cancer metastasis.

  20. Current aspects on bonding effectiveness and stability in adhesive dentistry.

    Science.gov (United States)

    Cardoso, M V; de Almeida Neves, A; Mine, A; Coutinho, E; Van Landuyt, K; De Munck, J; Van Meerbeek, B

    2011-06-01

    Improved dental adhesive technology has extensively influenced modern concepts in restorative dentistry. In light of minimal-invasive dentistry, this new approach promotes a more conservative cavity design, which basically relies on the effectiveness of current enamel-dentine adhesives. Nowadays, the interaction of adhesives with the dental substrate is based on two different strategies, commonly described as an etch-and-rinse and a self-etch approach. In an attempt to simplify the bonding technique, manufacturers have decreased the number of steps necessary for the accomplishment of the bonding procedure. As a consequence, two-step etch-and-rinse and one-step (self-etch) adhesives were introduced and gained rapid popularity in the dental market due to their claimed user-friendliness and lower technique sensitivity. However, many concerns have been raised on the bonding effectiveness of these simplified adhesives, especially in terms of durability, although this tends to be very material dependent. In order to blend all the adhesive components into one single solution, one-step adhesives were made more acidic and hydrophilic. Unfortunately, these properties induce a wide variety of seemingly unrelated problems that may jeopardize the effectiveness and stability of adhesion to the dental substrate. Being more susceptible to water sorption and thus nanoleakage, these adhesives are more prone to bond degradation and tend to fail prematurely as compared to their multi-step counterparts. Incidentally, another factor that may interfere with the bonding effectiveness of adhesives is the technique used for caries removal and cavity preparation. Several tools are on the market today to effectively remove carious tissue, thereby respecting the current trend of minimum intervention. Despite their promising performance, such techniques modify the tooth substrate in different aspects, possibly affecting bonding effectiveness. Altogether, we may conclude that not only the

  1. Frictional adhesion: A new angle on gecko attachment.

    Science.gov (United States)

    Autumn, K; Dittmore, A; Santos, D; Spenko, M; Cutkosky, M

    2006-09-01

    Directional arrays of branched microscopic setae constitute a dry adhesive on the toes of pad-bearing geckos, nature's supreme climbers. Geckos are easily and rapidly able to detach their toes as they climb. There are two known mechanisms of detachment: (1) on the microscale, the seta detaches when the shaft reaches a critical angle with the substrate, and (2) on the macroscale, geckos hyperextend their toes, apparently peeling like tape. This raises the question of how geckos prevent detachment while inverted on the ceiling, where body weight should cause toes to peel and setal angles to increase. Geckos use opposing feet and toes while inverted, possibly to maintain shear forces that prevent detachment of setae or peeling of toes. If detachment occurs by macroscale peeling of toes, the peel angle should monotonically decrease with applied force. In contrast, if adhesive force is limited by microscale detachment of setae at a critical angle, the toe detachment angle should be independent of applied force. We tested the hypothesis that adhesion is increased by shear force in isolated setal arrays and live gecko toes. We also tested the corollary hypotheses that (1) adhesion in toes and arrays is limited as on the microscale by a critical angle, or (2) on the macroscale by adhesive strength as predicted for adhesive tapes. We found that adhesion depended directly on shear force, and was independent of detachment angle. Therefore we reject the hypothesis that gecko toes peel like tape. The linear relation between adhesion and shear force is consistent with a critical angle of release in live gecko toes and isolated setal arrays, and also with our prior observations of single setae. We introduced a new model, frictional adhesion, for gecko pad attachment and compared it to existing models of adhesive contacts. In an analysis of clinging stability of a gecko on an inclined plane each adhesive model predicted a different force control strategy. The frictional adhesion

  2. Aspirin and pravastatin reduce lectin-like oxidized low density lipoprotein receptor-1 expression, adhesion molecules and oxidative stress in human coronary artery endothelial cells

    Institute of Scientific and Technical Information of China (English)

    CHEN Jia-wei; ZHOU Shi-bei; TAN Zhi-ming

    2010-01-01

    Background Oxidative stress and inflammation are important steps in the pathogenesis of atherosclerosis. We postulated that therapeutic concentrations of aspirin and pravastatin, especially in combination, may suppress oxidative stress and inflammation in endothelial cells, and this concept was examined in human coronary artery endothelial cells (HCAECs).Methods Human coronary artery endothelial cells were cultured and treated with oxidized-low density iipoprotein (ox-LDL, 60 μg/ml for 24 hours) alone, or pre-treated with aspirin (1, 2 or 5 mmol/L), pravastatin (1, 5 or 10 μmol/L) or their combination (1 mmol/L aspirin and 5 μmol/L pravastatin), followed by ox-LDL treatment. After respective treatment,superoxide anion production, p38 mitogen activated protein kinase and transcription factor NF-κB activation, protein expression of lectin-like ox-LDL receptor-1 (LOX-1) and adhesion molecules, and monocyte adhesion were measured.Results Ox-LDL treatment greatly elicited its receptor LOX-1 expression, superoxide anion production and inflammatory response, which were minimally affected by low concentration of aspidn (1 mmol/L) or pravastatin (5 μmol/L), but were markedly decreased by their combination. Activation of p38 mitogen activated protein kinase and NF-κB, the expression of intercellular adhesion molecule-1 and monocyte chemotactic protein-1, which were only mildly affected by aspirin or pravastatin alone, were significantly attenuated by their combination. As a consequence, monocyte adhesion to endothelial cells was markedly attenuated by the combination of the two agents. Well-known anti-oxidants α-tocopherol and γ-tocopherol had similar inhibitory effects on ox-LDL-mediated oxidative stress and LOX-1 expression as well as monocyte adhesion as did the combination of aspirin and pravastatin.Conclusions These studies point to a positive interaction between aspidn and pravastatin with regard to endothelial biology. Anti-oxidant and subsequent anti

  3. SRC kinase regulation in progressively invasive cancer.

    Directory of Open Access Journals (Sweden)

    Weichen Xu

    Full Text Available Metastatic progression is a multistep process that involves tumor growth and survival, motility and invasion, and subsequent proliferation in an inappropriate environment. The Src protein tyrosine kinase has been implicated in many of the biochemical pathways that drive these behaviors. Although Src itself is only rarely mutated in human tumors, its aberrant activity has been noted in various cancers and suggested to serve as a barometer of metastatic potential. With these features in mind, we examined Src kinase regulation at the structural, enzymatic, and expression levels as a function of progressively invasive prostate cancer cell lines. Surprisingly, both total Src content and kinase activity decrease with increasing cell line aggressiveness, an observation that appears to be inconsistent with the well-documented role of Src in the signaling pathways that drive growth and invasion. However, we do observe a direct correlation between Src kinase specific activity (total Src kinase activity/total Src content and metastatic aggressiveness, possibly suggesting that in highly aggressive cell lines, key signaling enzymes are globally recruited to drive the cancerous phenotype. In addition, although the expected enhanced phosphorylation of Src at Tyr-416 (activation site is present in the most aggressive prostate cancer cell lines, unexpectedly high phosphorylation levels at the Tyr-527 inhibitory site are observed as well. The latter, rather than representative of inhibited enzyme, is more indicative of primed Src responsive to local phosphorylated binding partners.

  4. Effect of water storage on the bonding effectiveness of 6 adhesives to Class I cavity dentin.

    Science.gov (United States)

    De Munck, Jan; Shirai, Kenichi; Yoshida, Yasuhiro; Inoue, Satoshi; Van Landuyt, Kirsten; Lambrechts, Paul; Suzuki, Kazuomi; Shintani, Hideaki; Van Meerbeek, Bart

    2006-01-01

    Adhesive-dentin interfaces degrade with time. This study determined the effect water storage may have on the bonding effectiveness of adhesives to occlusal Class I cavity-bottom dentin. Six adhesives, all representing contemporary classes of adhesives, were applied: a 3-step (OptiBond FL, Kerr) and 2-step (Scotchbond 1*, 3M ESPE) etch-and-rinse adhesive, a 2-step (Clearfil SE, Kuraray) and 1-step (Adper prompt, 3M ESPE) self-etch adhesive and a 2-step (FujiBond LC, GC) and 1-step (Reactmer, Shofu) resin-modified glass-ionomer adhesive. Bonding effectiveness was assessed by microtensile bond strength testing (MTBS) and electron microscopy (Feg-SEM and TEM). The MTBS was determined after 1 day and 1 year water storage of the entire restored cavity (indirect exposure of the adhesive-dentin interface to water) and prepared microTBS-beams (direct exposure of the adhesive-dentin interface to water). The hypotheses tested were: (1) resin-dentin bonds formed at the bottom of Class I cavities resist 1-year water storage and (2) an adjacent composite-enamel bond protects the composite-dentin bond against degradation. Non-parametric Kruskal-Wallis analysis statistically analyzed the microTBSs. The first hypothesis was rejected, as only the microTBS of OptiBond FL and Clearfil SE did not significantly decrease after 1-year direct and/or indirect water storage. The second hypothesis was corroborated, as the bonding effectiveness of most simplified adhesives (Scotchbond 1, Adper Prompt, FujiBond LC and Reactmer) approached 0 (because of the frequent pre-testing failures) after 1-year direct water exposure. The second hypothesis concluded that the 3-step etch-and-rinse adhesive must still be regarded the "gold standard." Though microTBS decreased significantly, Clearfil SE, as a 2-step self-etch adhesive, was the only simplified adhesive to perform reliably after 1-year direct water exposure.

  5. TANNIN ADHESIVES AS AN ALTENATIVE TO THE SYNTHETIC PHENOLIC ADHESIVES

    Directory of Open Access Journals (Sweden)

    Semra Çolak

    2003-04-01

    Full Text Available Recently, increasing attention has been paid industrially to the use of tannin formaldehyde adhesives in production of wood based panel products such as particleboard, fiber board and plywood. The researches on the use of tannin extracts as a wood adhesive started in 1950, however, they proceeded very slowly since the problems associated with the application of them. The idea which tannin extract can be used replace the oil-based phenolic adhesive was the base of several studies after the oil crisis of the 1970s. In the past, the economical aspects were important in the researches on the tannin-based adhesives. Nowadays, however, both economical and ecological factors should have taken into consideration in wood bonding.

  6. Decreasing Relative Risk Premium

    DEFF Research Database (Denmark)

    Hansen, Frank

    We consider the risk premium demanded by a decision maker with wealth x in order to be indifferent between obtaining a new level of wealth y1 with certainty, or to participate in a lottery which either results in unchanged present wealth or a level of wealth y2 > y1. We define the relative risk...... premium as the quotient between the risk premium and the increase in wealth y1–x which the decision maker puts on the line by choosing the lottery in place of receiving y1 with certainty. We study preferences such that the relative risk premium is a decreasing function of present wealth, and we determine...... relative risk premium in the small implies decreasing relative risk premium in the large, and decreasing relative risk premium everywhere implies risk aversion. We finally show that preferences with decreasing relative risk premium may be equivalently expressed in terms of certain preferences on risky...

  7. Decreasing Serial Cost Sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Østerdal, Lars Peter

    The increasing serial cost sharing rule of Moulin and Shenker [Econometrica 60 (1992) 1009] and the decreasing serial rule of de Frutos [Journal of Economic Theory 79 (1998) 245] have attracted attention due to their intuitive appeal and striking incentive properties. An axiomatic characterization...... of the increasing serial rule was provided by Moulin and Shenker [Journal of Economic Theory 64 (1994) 178]. This paper gives an axiomatic characterization of the decreasing serial rule...

  8. Photovoltaic module with adhesion promoter

    Science.gov (United States)

    Xavier, Grace

    2013-10-08

    Photovoltaic modules with adhesion promoters and methods for fabricating photovoltaic modules with adhesion promoters are described. A photovoltaic module includes a solar cell including a first surface and a second surface, the second surface including a plurality of interspaced back-side contacts. A first glass layer is coupled to the first surface by a first encapsulating layer. A second glass layer is coupled to the second surface by a second encapsulating layer. At least a portion of the second encapsulating layer is bonded directly to the plurality of interspaced back-side contacts by an adhesion promoter.

  9. Adhesives from modified soy protein

    Science.gov (United States)

    Sun, Susan; Wang, Donghai; Zhong, Zhikai; Yang, Guang

    2008-08-26

    The, present invention provides useful adhesive compositions having similar adhesive properties to conventional UF and PPF resins. The compositions generally include a protein portion and modifying ingredient portion selected from the group consisting of carboxyl-containing compounds, aldehyde-containing compounds, epoxy group-containing compounds, and mixtures thereof. The composition is preferably prepared at a pH level at or near the isoelectric point of the protein. In other preferred forms, the adhesive composition includes a protein portion and a carboxyl-containing group portion.

  10. Effect of thermal aging on the tensile bond strength at reduced areas of seven current adhesives.

    Science.gov (United States)

    Baracco, Bruno; Fuentes, M Victoria; Garrido, Miguel A; González-López, Santiago; Ceballos, Laura

    2013-07-01

    The purpose of this study was to determine the micro-tensile bond strength (MTBS) to dentin of seven adhesive systems (total and self-etch adhesives) after 24 h and 5,000 thermocycles. Dentin surfaces of human third molars were exposed and bonded with two total-etch adhesives (Adper Scotchbond 1 XT and XP Bond), two two-step self-etch adhesives (Adper Scotchbond SE and Filtek Silorane Adhesive System) and three one-step self-etch adhesives (G-Bond, Xeno V and Bond Force). All adhesive systems were applied following manufacturers' instructions. Composite buildups were constructed and the bonded teeth were then stored in water (24 h, 37 °C) or thermocycled (5,000 cycles) before being sectioned and submitted to MTBS test. Two-way ANOVA and subsequent comparison tests were applied at α = 0.05. Characteristic de-bonded specimens were analyzed using scanning electron microscopy (SEM). After 24 h water storage, MTBS values were highest with XP Bond, Adper Scotchbond 1 XT, Filtek Silorane Adhesive System and Adper Scotchbond SE and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. After thermocycling, MTBS values were highest with XP Bond, followed by Filtek Silorane Adhesive System, Adper Scotchbond SE and Adper Scotchbond 1 XT and lowest with the one-step self-etch adhesives Bond Force, Xeno V and G-Bond. Thermal aging induced a significant decrease in MTBS values with all adhesives tested. The resistance of resin-dentin bonds to thermal-aging degradation was material dependent. One-step self-etch adhesives obtained the lowest MTBS results after both aging treatments, and their adhesive capacity was significantly reduced after thermocycling.

  11. Adhesion of Spores of Bacillus thuringiensis on a Planar Surface

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Lee, Ida [University of Tennessee, Knoxville (UTK); Joy, David Charles [ORNL; Palumbo, Anthony Vito [ORNL; Tsouris, Costas [ORNL

    2010-01-01

    Adhesion of spores of Bacillus thuringiensis (Bt) and spherical silica particles on surfaces was experimentally and theoretically investigated in this study. Topography analysis via atomic force microscopy (AFM) and electron microscopy indicates that Bt spores are rod shaped, {approx}1.3 {mu}m in length and {approx}0.8 {mu}m in diameter. The adhesion force of Bt spores and silica particles on gold-coated glass was measured at various relative humidity (RH) levels by AFM. It was expected that the adhesion force would vary with RH because the individual force components contributing to the adhesion force depend on RH. The adhesion force between a particle and a planar surface in atmospheric environments was modeled as the contribution of three major force components: capillary, van der Waals, and electrostatic interaction forces. Adhesion force measurements for Bt spore (silica particle) and the gold surface system were comparable with calculations. Modeling results show that there is a critical RH value, which depends on the hydrophobicity of the materials involved, below which the water meniscus does not form and the contribution of the capillary force is zero. As RH increases, the van der Waals force decreases while the capillary force increases to a maximum value.

  12. Enhanced platelet adhesion in essential thrombocythemia after in vitro activation

    Directory of Open Access Journals (Sweden)

    Andreas C. Eriksson

    2010-06-01

    Full Text Available Objective: Essential thrombocythemia (ET is a chronic myeloproliferative disorder characterized by elevated platelet counts and increased risk of thrombosis. Ex vivo data suggest increased platelet reactivity in agreement with the increased thrombosis risk, while in vitro tests often detect decreased platelet activity. The present study aimed to investigate adhesion of ET-platelets in vitro, which is an aspect of platelet function that has been addressed in only a few studies on ET patients. Material and Methods: The study included 30 ET patients and 14 healthy controls. Platelet adhesion was measured with a static platelet adhesion assay. Results: The main finding was that ET-platelets were more readily activated by adhesion-inducing stimuli in vitro than control platelets. This was particularly evident in elderly patients and when using multiple stimuli, such as surfaces of collagen or fibrinogen combined with addition of adenosine 5’-diphosphate or ristocetin. Such multiple stimuli resulted in adhesion above the control mean +2 standard deviations for approximately 50% of the patients.Conclusion: The results are in accordance with the concept of increased platelet activity in ET, but opposite to most other in vitro studies. We suggest that the conditions in the adhesion assay might mimic the in vivo situation regarding the presence of chronic platelet activation.

  13. Adhesion between silica surfaces due to hydrogen bonding

    Science.gov (United States)

    Bowen, James; Rossetto, Hebert L.; Kendall, Kevin

    2016-09-01

    The adhesion between surfaces can be enhanced significantly by the presence of hydrogen bonding. Confined water at the nanoscale can display behaviour remarkably different to bulk water due to the formation of hydrogen bonds between two surfaces. In this work we investigate the role of confined water on the interaction between hydrophilic surfaces, specifically the effect of organic contaminants in the aqueous phase, by measuring the peak adhesive force and the work of adhesion. Atomic force microscope cantilevers presenting hemispherical silica tips were interacted with planar single crystals of silica in the presence of dimethylformamide, ethanol, and formamide; solution compositions in the range 0-100 mol% water were investigated for each molecule. Each molecule was chosen for its ability to hydrogen bond with water molecules, with increasing concentrations likely to disrupt the structure of surface-bound water layers. With the exception of aqueous solutions containing low concentrations of ethanol, all molecules decreased the ability of confined water to enhance the adhesion between the silica surfaces in excess of the predicted theoretical adhesion due to van der Waals forces. The conclusion was that adhesion depends strongly on the formation of a hydrogen-bonding network within the water layers confined between the silica surfaces.

  14. Treatment to Control Adhesion of Silicone-Based Elastomers

    Science.gov (United States)

    deGroh, Henry C., III; Puleo, Bernadette J.; Waters, Deborah L.

    2013-01-01

    Seals are used to facilitate the joining of two items, usually temporarily. At some point in the future, it is expected that the items will need to be separated. This innovation enables control of the adhesive properties of silicone-based elastomers. The innovation may also be effective on elastomers other than the silicone-based ones. A technique has been discovered that decreases the level of adhesion of silicone- based elastomers to negligible levels. The new technique causes less damage to the material compared to alternative adhesion mitigation techniques. Silicone-based elastomers are the only class of rubber-like materials that currently meet NASA s needs for various seal applications. However, silicone-based elastomers have natural inherent adhesive properties. This stickiness can be helpful, but it can frequently cause problems as well, such as when trying to get items apart. In the past, seal adhesion was not always adequately addressed, and has caused in-flight failures where seals were actually pulled from their grooves, preventing subsequent spacecraft docking until the seal was physically removed from the flange via an extravehicular activity (EVA). The primary method used in the past to lower elastomer seal adhesion has been the application of some type of lubricant or grease to the surface of the seal. A newer method uses ultraviolet (UV) radiation a mixture of UV wavelengths in the range of near ultraviolet (NUV) and vacuum ultraviolet (VUV) wavelengths.

  15. A Bone Glue with Sustained Adhesion under Wet Conditions.

    Science.gov (United States)

    Wistlich, Laura; Rücker, Anja; Schamel, Martha; Kübler, Alexander C; Gbureck, Uwe; Groll, Jürgen

    2017-02-01

    Bone glues often suffer from low adhesion to bone under wet conditions. This study aims to improve wet adhesiveness of a bone glue based on a photocurable poly(ethylene glycol) dimethacrylate matrix through in situ interpenetrating network formation by addition of six-armed isocyanate functional star-shaped prepolymers (NCO-sP(EO-stat-PO)). Biodegradable ceramic fillers are added to adjust the paste workability. The 3-point bending strength of the bone glues is in the range of 3.5-5.5 MPa and not significantly affected by the addition of NCO-sP(EO-stat-PO). Storage in phosphate buffered saline (PBS) decreases the bending strength of all formulations to approximately 1 MPa but the adhesion to cortical bone increases from 0.15-0.2 to 0.3-0.5 MPa after adding 20-40 wt% NCO-sP(EO-stat-PO) to the matrix. Bone glues without the NCO-sP(EO-stat-PO) additive lose their adhesiveness to bone after aging in PBS for 7 days, whereas modified glues maintain a shear strength of 0.18-0.25 MPa demonstrating the efficacy of the approach. Scanning electron microscopy and energy-dispersive X-ray spectroscopy investigations of the fracture surfaces prove a high amount of residual adhesive on the bone surface indicating that adhesion to the bone under wet conditions is stronger than cohesion.

  16. Enterococcus faecalis phosphomevalonate kinase.

    Science.gov (United States)

    Doun, Stephanie S; Burgner, John W; Briggs, Scott D; Rodwell, Victor W

    2005-05-01

    The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram-positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic DNA and the polymerase chain reaction were used to clone DNA thought to encode phosphomevalonate kinase into pET28b(+). Double-stranded DNA sequencing verified the sequence of the recombinant gene. The encoded N-terminal hexahistidine-tagged protein was expressed in Escherichia coli with induction by isopropylthiogalactoside and purified by Ni(++) affinity chromatography, yield 20 mg protein per liter. Analysis of the purified protein by MALDI-TOF mass spectrometry established it as E. faecalis phosphomevalonate kinase. Analytical ultracentrifugation revealed that the kinase exists in solution primarily as a dimer. Assay for phosphomevalonate kinase activity used pyruvate kinase and lactate dehydrogenase to couple the formation of ADP to the oxidation of NADH. Optimal activity occurred at pH 8.0 and at 37 degrees C. The activation energy was approximately 5.6 kcal/mol. Activity with Mn(++), the preferred cation, was optimal at about 4 mM. Relative rates using different phosphoryl donors were 100 (ATP), 3.6 (GTP), 1.6 (TTP), and 0.4 (CTP). K(m) values were 0.17 mM for ATP and 0.19 mM for (R,S)-5-phosphomevalonate. The specific activity of the purified enzyme was 3.9 micromol substrate converted per minute per milligram protein. Applications to an immobilized enzyme bioreactor and to drug screening and design are discussed.

  17. Phosphoproteome reveals an atlas of protein signaling networks during osteoblast adhesion.

    Science.gov (United States)

    Milani, Renato; Ferreira, Carmen V; Granjeiro, José M; Paredes-Gamero, Edgar J; Silva, Rodrigo A; Justo, Giselle Z; Nader, Helena B; Galembeck, Eduardo; Peppelenbosch, Maikel P; Aoyama, Hiroshi; Zambuzzi, Willian F

    2010-04-01

    Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important regulatory mechanism in eukaryotes. Therefore, the goal of this study is to assess osteoblast adhesion through a molecular prism under a peptide array technology, revealing essential signaling proteins governing adhesion-related events. First, we showed that there are main morphological changes on osteoblast shape during adhesion up to 3 h. Second, besides classical proteins activated upon integrin activation, our results showed a novel network involving signaling proteins such as Rap1A, PKA, PKC, and GSK3beta during osteoblast adhesion on polystyrene. Third, these proteins were grouped in different signaling cascades including focal adhesion establishment, cytoskeleton rearrangement, and cell-cycle arrest. We have thus provided evidence that a global phosphorylation screening is able to yield a systems-oriented look at osteoblast adhesion, providing new insights for understanding of bone formation and improvement of cell-substratum interactions. Altogether, these statements are necessary means for further intervention and development of new approaches for the progress of tissue engineering.

  18. The structural features of Trask that mediate its anti-adhesive functions.

    Directory of Open Access Journals (Sweden)

    Danislav S Spassov

    Full Text Available Trask/CDCP1 is a transmembrane protein with a large extracellular and small intracellular domains. The intracellular domain (ICD undergoes tyrosine phosphorylation by Src kinases during anchorage loss and, when phosphorylated, Trask functions to inhibit cell adhesion. The extracellular domain (ECD undergoes proteolytic cleavage by serine proteases, although the functional significance of this remains unknown. There is conflicting evidence regarding whether it functions to signal the phosphorylation of the ICD. To better define the structural determinants that mediate the anti-adhesive functions of Trask, we generated a series of deletion mutants of Trask and expressed them in tet-inducible cell models to define the structural elements involved in cell adhesion signaling. We find that the ECD is dispensable for the phosphorylation of the ICD or for the inhibition of cell adhesion. The anti-adhesive functions of Trask are entirely embodied within its ICD and are specifically due to tyrosine phosphorylation of the ICD as this function is completely lost in a phosphorylation-defective tyrosine-phenylalanine mutant. Both full length and cleaved ECDs are fully capable of phosphorylation and undergo phosphorylation during anchorage loss and cleavage is not an upstream signal for ICD phosphorylation. These data establish that the anti-adhesive functions of Trask are mediated entirely through its tyrosine phosphorylation. It remains to be defined what role, if any, the Trask ECD plays in its adhesion functions.

  19. Decreasing strabismus surgery

    Science.gov (United States)

    Arora, A; Williams, B; Arora, A K; McNamara, R; Yates, J; Fielder, A

    2005-01-01

    Aim: To determine whether there has been a consistent change across countries and healthcare systems in the frequency of strabismus surgery in children over the past decade. Methods: Retrospective analysis of data on all strabismus surgery performed in NHS hospitals in England and Wales, on children aged 0–16 years between 1989 and 2000, and between 1994 and 2000 in Ontario (Canada) hospitals. These were compared with published data for Scotland, 1989–2000. Results: Between 1989 and 1999–2000 the number of strabismus procedures performed on children, 0–16 years, in England decreased by 41.2% from 15 083 to 8869. Combined medial rectus recession with lateral rectus resection decreased from 5538 to 3013 (45.6%) in the same period. Bimedial recessions increased from 489 to 762, oblique tenotomies from 43 to 121, and the use of adjustable sutures from 29 to 44, in 2000. In Ontario, operations for squint decreased from 2280 to 1685 (26.1%) among 0–16 year olds between 1994 and 2000. Conclusion: The clinical impression of decrease in the frequency of paediatric strabismus surgery is confirmed. In the authors’ opinion this cannot be fully explained by a decrease in births or by the method of healthcare funding. Two factors that might have contributed are better conservative strabismus management and increased subspecialisation that has improved the quality of surgery and the need for re-operation. This finding has a significant impact upon surgical services and also on the training of ophthalmologists. PMID:15774914

  20. Regulative mechanisms of chondrocyte adhesion

    DEFF Research Database (Denmark)

    Schmal, Hagen; Mehlhorn, Alexander T; Fehrenbach, Miriam;

    2006-01-01

    -matrix interaction, as well as collagen type II expression in the cartilage graft after two weeks of in vitro cultivation. Basic fibroblast growth factor (bFGF) treated chondrocytes showed increased adhesion to collagen types I and II, fibronectin, and fibrinogen. Attachment to these investigated proteins......%) increased. A cartilage construct was developed based on a clinically established collagen type I scaffold. In this matrix, more than 80% of the cells could be immobilized by mechanisms of adhesion, filtration, and cell entrapment. Confocal laser microscopy revealed focal adhesion sites as points of cell...... significantly enhanced cell proliferation. Matrix design in cartilage engineering must meet the biological demands of amplified cells, because adhesion of chondrocytes depends on their differentiation status and is regulated by bFGF....

  1. Adhesion Transition of Flexible Filaments

    Science.gov (United States)

    Evans, Arthur; Lauga, Eric

    2009-03-01

    As forays into fabrication and self-assembly venture to increasingly small length scales, the role of adhesion events between material elements of the system must be closely scrutinized. This area of study is typically dominated by investigations into capillary adhesion, but relatively recent interest in carbon nanotubes and biomimetic devices have spurred interest in intermolecular forces as another source of micro- and nano-scale adhesion. We present here a far-field model for ``dry'' adhesion. We consider a small number N of flexible beams interacting with each other via a typical Lennard-Jones 6-12 potential, and describe the behavior of the system as the ratio of bending rigidity to beam-beam attraction is reduced. Applications ranging from fibrillar systems to the comparatively stiff carbon nanotubes are discussed.

  2. Laser surface modification and adhesion

    CERN Document Server

    Mittal, K L

    2014-01-01

    The book provides a unique overview on laser techniques and applications for the purpose of improving adhesion by altering surface chemistry and topography/morphology of the substrate. It details laser surface modification techniques for a wide range of industrially relevant materials (plastics, metals, ceramics, composites) with the aim to improve and enhance their adhesion to other materials. The joining of different materials is of critical importance in the fabrication of many and varied products.

  3. Mechanisms of adhesion in geckos.

    Science.gov (United States)

    Autumn, Kellar; Peattie, Anne M

    2002-12-01

    The extraordinary adhesive capabilities of geckos have challenged explanation for millennia, since Aristotle first recorded his observations. We have discovered many of the secrets of gecko adhesion, yet the millions of dry, adhesive setae on the toes of geckos continue to generate puzzling new questions and valuable answers. Each epidermally-derived, keratinous seta ends in hundreds of 200 nm spatular tips, permitting intimate contact with rough and smooth surfaces alike. Prior studies suggested that adhesive force in gecko setae was directly proportional to the water droplet contact angle (θ) , an indicator of the free surface energy of a substrate. In contrast, new theory suggests that adhesion energy between a gecko seta and a surface (W(GS)) is in fact proportional to (1 + cosθ), and only for θ > 60°. A reanalysis of prior data, in combination with our recent study, support the van der Waals hypothesis of gecko adhesion, and contradict surface hydrophobicity as a predictor of adhesion force. Previously, we and our collaborators measured the force production of a single seta. Initial efforts to attach a seta failed because of improper 3D orientation. However, by simulating the dynamics of gecko limbs during climbing (based on force plate data) we discovered that, in single setae, a small normal preload, combined with a 5 μm displacement yielded a very large adhesive force of 200 microNewton (μN), 10 times that predicted by whole-animal measurements. 6.5 million setae of a single tokay gecko attached maximally could generate 130 kg force. This raises the question of how geckos manage to detach their feet in just 15 ms. We discovered that simply increasing the angle that the setal shaft makes with the substrate to 30° causes detachment. Understanding how simultaneous attachment and release of millions of setae are controlled will require an approach that integrates levels ranging from molecules to lizards.

  4. Effect of adhesive thickness and surface treatment on shear strength on single lap joint Al/CFRP using adhesive of epoxy/Al fine powder

    Science.gov (United States)

    Diharjo, Kuncoro; Anwar, Miftahul; Tarigan, Roy Aries P.; Rivai, Ahmad

    2016-02-01

    The objective of this study is to investigate the effect of adhesive thickness and surface treatment on the shear strength and failure type characteristic of single lap joint (SLJ) CFRP/Al using adhesive epoxy/Al-fine-powder. The CFRP was produced by using hand layup method for 30% of woven roving carbon fiber (w/w) and the resin used was bisphenolic. The adhesive was prepared using 12.5% of aluminum fine powder (w/w) in the epoxy adhesive. The powder was mixed by using a mixing machine at 60 rpm for 6 minutes, and then it was used to join the Al plate-2024 and CFRP. The start time to pressure for the joint process was 20 minutes after the application of adhesive on the both of adherends. The variables in this research are adhesive thickness (i.e. 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm and 1 mm) and surface treatment of adherends (i.e. acetone, chromate sulphuric acid, caustic etch and tucker's reagent). Before shear testing, all specimens were post-cured at 100 °C for 15 minutes. The result shows that the SLJ has the highest shear strength for 0.4 mm of adhesive thickness. When the adhesive thickness is more than 0.4 mm (0.6-1 mm), the shear strength decreases significantly. It might be caused by the property change of adhesive from ductile to brittle. The acetone surface treatment produces the best bonding between the adhesive and adherends (CFRP and Al-plate 2024), and the highest shear strength is 9.31 MPa. The surface treatment give the humidification effect of adherend surfaces by adhesive. The failure characteristic shows that the mixed failure of light-fiber-tear-failure and cohesive-failure are occurred on the high shear strength of SLJ, and the low shear strength commonly has the adhesive-failure type.

  5. 21 CFR 878.4010 - Tissue adhesive.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tissue adhesive. 878.4010 Section 878.4010 Food... DEVICES GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4010 Tissue adhesive. (a) Tissue adhesive for the topical approximation of skin—(1) Identification. A tissue adhesive for the...

  6. Contraction stress in dentin adhesives bonded to dentin.

    Science.gov (United States)

    Hashimoto, M; de Gee, A J; Kaga, M; Feilzer, A J

    2006-08-01

    Adhesives cured under constrained conditions develop contraction stresses. We hypothesized that, with dentin as a bonding substrate, the stress would reach a maximum, followed by a continuous decline. Stress development was determined with a tensilometer for two total-etch systems and two systems with self-etching primers. The adhesives were placed in a thin layer between a glass plate and a flat dentin surface pretreated with phosphoric acid or self-etching primer. After an initial maximum shortly after light-curing, the stress decreased dramatically for the total-etch systems (70%) and, to a lesser extent, for the adhesives with self-etching primers (30%). The greater stress decrease for the total-etch systems was ascribed to water and/or solvents released into the adhesives from the fully opened dentinal tubules by the pulling/sucking action of the contraction stress. This happened less with the adhesives with self-etching primers, where the tubules remained mainly closed.

  7. Fibrillar Adhesive for Climbing Robots

    Science.gov (United States)

    Pamess, Aaron; White, Victor E.

    2013-01-01

    A climbing robot needs to use its adhesive patches over and over again as it scales a slope. Replacing the adhesive at each step is generally impractical. If the adhesive or attachment mechanism cannot be used repeatedly, then the robot must carry an extra load of this adhesive to apply a fresh layer with each move. Common failure modes include tearing, contamination by dirt, plastic deformation of fibers, and damage from loading/ unloading. A gecko-like fibrillar adhesive has been developed that has been shown useful for climbing robots, and may later prove useful for grasping, anchoring, and medical applications. The material consists of a hierarchical fibrillar structure that currently contains two levels, but may be extended to three or four levels in continuing work. The contacting level has tens of thousands of microscopic fibers made from a rubberlike material that bend over and create intimate contact with a surface to achieve maximum van der Waals forces. By maximizing the real area of contact that these fibers make and minimizing the bending energy necessary to achieve that contact, the net amount of adhesion has been improved dramatically.

  8. Exploring the formation of focal adhesions on patterned surfaces using super-resolution imaging.

    Science.gov (United States)

    Chien, Fan-Ching; Kuo, Chiung Wen; Yang, Zong-Han; Chueh, Di-Yen; Chen, Peilin

    2011-10-17

    The formation of focal adhesions on various sizes of fibronectin patterns, ranging from 200 μm to 250 nm, was systematically investigated by total internal reflection fluorescence microscopy and super-resolution imaging. It was found that cells adhered to and spread on these micro/nanopatterns, forming focal adhesions. On a micrometer scale the shape of the focal adhesions was elongated. However, on the nanometer scale, the shape of focal adhesions became dotlike. To further explore the distribution of focal adhesion proteins formed on surfaces, a localization-based super-resolution imaging technique was employed in order to determine the position and density of vinculin proteins. A characteristic distance of 50 nm was found between vinculin molecules in the focal adhesions, which did not depend on the size of the fibronectin nanopatterns. This distance was found to be crucial for the formation of focal adhesions. In addition, the density of vinculin at the focal adhesions formed on the nanopatterns increased as the pattern size decreased. The density of the protein was found to be 425 ± 247, 584 ± 302, and 703 ± 305 proteins μm(-2) on the 600, 400, and 250 nm fibronectin patterns respectively. Whereas 226 ± 77 proteins μm(-2) was measured for the matured focal adhesions on homogeneous fibronectin coated substrates. The increase in vinculin density implies that an increase in mechanical load was applied to the focal adhesions formed on the smaller nanopatterns.

  9. Identification of Differentially Expressed Kinase and Screening Potential Anticancer Drugs in Papillary Thyroid Carcinoma

    Science.gov (United States)

    Zhang, Huairong

    2016-01-01

    Aim. We aim to identify protein kinases involved in the pathophysiology of papillary thyroid carcinoma (PTC) in order to provide potential therapeutic targets for kinase inhibitors and unfold possible molecular mechanisms. Materials and Methods. The gene expression profile of GSE27155 was analyzed to identify differentially expressed genes and mapped onto human protein kinases database. Correlation of kinases with PTC was addressed by systematic literature search, GO and KEGG pathway analysis. Results. The functional enrichment analysis indicated that “mitogen-activated protein kinases pathway” expression was extremely enriched, followed by “neurotrophin signaling pathway,” “focal adhesion,” and “GnRH signaling pathway.” MAPK, SRC, PDGFRa, ErbB, and EGFR were significantly regulated to correct these pathways. Kinases investigated by the literature on carcinoma were considered to be potential novel molecular therapeutic target in PTC and application of corresponding kinase inhibitors could be possible therapeutic tool. Conclusion. SRC, MAPK, and EGFR were the most important differentially expressed kinases in PTC. Combined inhibitors may have high efficacy in PTC treatment by targeting these kinases. PMID:27703281

  10. [Studies on the pre-treatment of dental alloy for adhesive restorations. 4. Adhesive durability of adhesive resin to various dental alloys treated with composite plating].

    Science.gov (United States)

    Kondo, Y; Yamashita, A; Suzuki, K; Omura, I; Yamauchi, J I

    1989-07-01

    In this study, the durability of adhesion between an adhesive resin (Panavia EX) and dental alloys (gold or Ni-Cr) were examined in regard to thermal cycling, immersion, either in water (70 degrees C or 100 degrees C) or in sodium chloride solutions (pH was 3, 7 and 9). An favourable adhesive strength, such as 450-500 kgf/cm2, was obtained even after 24 hours immersion in 37 degrees C water, when the surface pre-treatment of the alloy was done with either Sn- or composite (TMSAC/Sn or PVC/Sn)-plating. However, during the durability test, the adhesive strength has decreased to such on extent, that about 60% of early strength with Sn-plating and 80% with TMSAC/Sn composite plating. But, with PVC/Sn composite-plating, more than 90% of the early strength was maintained. In regard to the pH of the corrosive solution, no apparent difference was observed regarding the above mentioned adhesive characteristics.

  11. Adhesion of smooth and rough phenotypes of Flavobacterium psychrophilum to polystyrene surfaces.

    Science.gov (United States)

    Högfors-Rönnholm, E; Norrgård, J; Wiklund, T

    2015-05-01

    Phenotypic smooth cells of the fish pathogenic bacterium Flavobacterium psychrophilum have previously been reported to be more adhesive to polystyrene surfaces than corresponding rough cells. In this study, the adhesion ability of smooth and rough cells of F. psychrophilum to polystyrene surfaces was investigated in detail with a crystal violet staining method. By treating both polystyrene surfaces with fish mucus and carbohydrates and the bacterial cells with carbohydrates, the involvement of lectins in the adhesion process was investigated. Smooth cells showed significantly higher adhesion ability to untreated polystyrene surfaces compared with corresponding rough cells and increasing water hardness had an inhibitory effect on the adhesion. Treatment of polystyrene surfaces with D-glucose, D-galactose and fish mucus increased the adhesion ability of smooth cells to polystyrene. Furthermore, treatment of the smooth cells with D-glucose, D-galactose and sialic acid decreased the adhesion ability of the cells, indicating that the adhesion is likely mediated by complementary lectins on the surface of the cells. Sodium (meta)periodate treatment of smooth cells also decreased the adhesion ability to polystyrene, suggesting that the lectins, such as the dominating sialic acid-binding lectin, are probably localized in the extracellular polysaccharides surrounding the cells.

  12. The in vitro effect of desflurane preconditioning on endothelial adhesion molecules and mRNA expression.

    Science.gov (United States)

    Biao, Zhu; Zhanggang, Xue; Hao, Jiang; Changhong, Miao; Jing, Cang

    2005-04-01

    Lower expression of intercellular adhesion molecule-1 (ICAM-1), vascular adhesion molecule-1 (VCAM-1), and E-selectin may be responsible for attenuated ischemic-reperfusion neutrophil adhesion to vascular endothelium. Desflurane reduces ischemia-reperfusion injury. Therefore, we assessed whether desflurane affects the protein expression of ICAM-1 and E-selectin and mRNA expression of ICAM-1 and VCAM-1 of human umbilical venous endothelial cells (HUVEC) stimulated with tumor necrosis factor-alpha (TNF-alpha). HUVEC were preconditioned for 60 min with 1 minimum alveolar concentration desflurane before stimulating with TNF-alpha. Protein expression of adhesion molecules ICAM-1 and E-selectin of HUVEC were evaluated via immunocytochemical techniques combined with image cytometry. ICAM-1 and VCAM-1 mRNA expression of HUVEC were determined via reverse transcription-polymerase chain reaction. Desflurane not only reduced the protein expression of ICAM-1 and E-selectin but also ICAM-1 and VCAM-1 mRNA expression of the HUVEC. The adhesion rate of neutrophils with desflurane-treated HUVEC was slower. The decreased neutrophil adhesion on the desflurane-treated HUVEC correlated well with the decrease in adhesion molecule expression. These results show that desflurane affects the expression of adhesion molecules involved in the multistep process of neutrophil recruitment. Desflurane related ischemia-reperfusion injury reduction correlates well with expression inhibition of ICAM-1, VCAM-1, and E-selectin that mediates neutrophil rotation and firm adhesion on the vascular endothelium.

  13. Effect of repeated contact on adhesion measurements involving polydimethylsiloxane structural material

    Science.gov (United States)

    Kroner, E.; Maboudian, R.; Arzt, E.

    2009-09-01

    During the last few years several research groups have focused on the fabrication of artificial gecko inspired adhesives. For mimicking these structures, different polymers are used as structure material, such as polydimethylsiloxanes (PDMS), polyurethanes (PU), and polypropylene (PP). While these polymers can be structured easily and used for artificial adhesion systems, the effects of repeated adhesion testing have never been investigated closely. In this paper we report on the effect of repeated adhesion measurements on the commercially available poly(dimethylsiloxane) polymer kit Sylgard 184 (Dow Corning). We show that the adhesion force decreases as a function of contact cycles. The rate of change and the final value of adhesion are found to depend on the details of the PDMS synthesis and structuring.

  14. Effect of repeated contact on adhesion measurements involving polydimethylsiloxane structural material

    Energy Technology Data Exchange (ETDEWEB)

    Kroner, E; Arzt, E [INM-Leibniz Institute for New Materials, Campus D2 2, 66125 Saarbruecken (Germany); Maboudian, R, E-mail: elmar.kroner@inm-gmbh.de [Department of Chem. Eng., 201 Gilman Hall, University of California, Berkeley, CA 94720-1462 (United States)

    2009-09-15

    During the last few years several research groups have focused on the fabrication of artificial gecko inspired adhesives. For mimicking these structures, different polymers are used as structure material, such as polydimethylsiloxanes (PDMS), polyurethanes (PU), and polypropylene (PP). While these polymers can be structured easily and used for artificial adhesion systems, the effects of repeated adhesion testing have never been investigated closely. In this paper we report on the effect of repeated adhesion measurements on the commercially available poly(dimethylsiloxane) polymer kit Sylgard 184 (Dow Corning). We show that the adhesion force decreases as a function of contact cycles. The rate of change and the final value of adhesion are found to depend on the details of the PDMS synthesis and structuring.

  15. Neuron Membrane Trafficking and Protein Kinases Involved in Autism and ADHD

    Directory of Open Access Journals (Sweden)

    Yasuko Kitagishi

    2015-01-01

    Full Text Available A brain-enriched multi-domain scaffolding protein, neurobeachin has been identified as a candidate gene for autism patients. Mutations in the synaptic adhesion protein cell adhesion molecule 1 (CADM1 are also associated with autism spectrum disorder, a neurodevelopmental disorder of uncertain molecular origin. Potential roles of neurobeachin and CADM1 have been suggested to a function of vesicle transport in endosomal trafficking. It seems that protein kinase B (AKT and cyclic adenosine monophosphate (cAMP-dependent protein kinase A (PKA have key roles in the neuron membrane trafficking involved in the pathogenesis of autism. Attention deficit hyperactivity disorder (ADHD is documented to dopaminergic insufficiencies, which is attributed to synaptic dysfunction of dopamine transporter (DAT. AKT is also essential for the DAT cell-surface redistribution. In the present paper, we summarize and discuss the importance of several protein kinases that regulate the membrane trafficking involved in autism and ADHD, suggesting new targets for therapeutic intervention.

  16. The Rho kinases I and II regulate different aspects of myosin II activity

    DEFF Research Database (Denmark)

    Yoneda, Atsuko; Multhaupt, Hinke A B; Couchman, John R

    2005-01-01

    persistent ROCK II and guanine triphosphate-bound RhoA. In contrast, the microfilament cytoskeleton was enhanced by ROCK II down-regulation. Phagocytic uptake of fibronectin-coated beads was strongly down-regulated in ROCK II-depleted cells but not those lacking ROCK I. These effects originated in part from......The homologous mammalian rho kinases (ROCK I and II) are assumed to be functionally redundant, based largely on kinase construct overexpression. As downstream effectors of Rho GTPases, their major substrates are myosin light chain and myosin phosphatase. Both kinases are implicated in microfilament...... bundle assembly and smooth muscle contractility. Here, analysis of fibroblast adhesion to fibronectin revealed that although ROCK II was more abundant, its activity was always lower than ROCK I. Specific reduction of ROCK I by siRNA resulted in loss of stress fibers and focal adhesions, despite...

  17. Bond strength of adhesive resin cement with different adhesive systems

    Science.gov (United States)

    Lorenzoni e Silva, Fabrizio; Pamato, Saulo; Kuga, Milton-Carlos; Só, Marcus-Vinicius-Reis

    2017-01-01

    Background To assess the immediate bond strength of a dual-cure adhesive resin cement to the hybridized dentin with different bonding systems. Material and Methods Fifty-six healthy human molars were randomly divided into 7 groups (n=8). After 3 longitudinal sections, the central cuts were included in PVC matrix and were submitted to dentin hybridization according to the groups: G1 - etch & rinse system with 3-step (Apder™ Scotchbond™ Multi-Purpose, 3M ESPE), G2 - etch & rinse system with 3-step (Optibond™ FL, Kerr), G3 - etch & rinse system with 3-step (All-Bond 3®, Bisco), G4 - etch & rinse simplified system (Adper™ Single Bond 2, 3M ESPE), G5 - self-etching system with one step (Bond Force, Tokuyama), G6 - universal system in moist dentin (Single Bond Universal, 3M ESPE), G7 - universal system in dry dentin (Single Bond Universal, 3M ESPE). Then all groups received the cementing of a self-adhesive resin cement cylinder (Duo-link, Bisco) made from a polypropylene matrix. In the evaluation of bond strength, the samples were subjected to the microshear test and evaluated according to the fracture pattern by optical microscopy. Results The Kruskal-Wallis test suggests a statistically significant difference between groups (p=0,039), and Tukey for multiple comparisons, indicating a statistically significant difference between G3 and G4 (p<0.05). It was verified high prevalence of adhesive failures, followed by mixed failure and cohesive in dentin. Conclusions The technique and the system used to dentin hybridization are able to affect the immediate bond strength of resin cement dual adhesive. Key words:Adhesion, adhesive resin cement, adhesive systems, microshear. PMID:28149471

  18. Decreasing serial cost sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Østerdal, Lars Peter Raahave

    2009-01-01

    The increasing serial cost sharing rule of Moulin and Shenker (Econometrica 60:1009-1037, 1992) and the decreasing serial rule of de Frutos (J Econ Theory 79:245-275, 1998) are known by their intuitive appeal and striking incentive properties. An axiomatic characterization of the increasing serial...

  19. Decreasing Serial Cost Sharing

    DEFF Research Database (Denmark)

    Hougaard, Jens Leth; Østerdal, Lars Peter

    The increasing serial cost sharing rule of Moulin and Shenker [Econometrica 60 (1992) 1009] and the decreasing serial rule of de Frutos [Journal of Economic Theory 79 (1998) 245] have attracted attention due to their intuitive appeal and striking incentive properties. An axiomatic characterization...

  20. Plant phosphatidylinositol 3-kinase

    NARCIS (Netherlands)

    Lee, Y.; Munnik, T.; Munnik, T.

    2010-01-01

    Phosphatidylinositol 3-kinase (PI3K) phosphorylates the D-3 position of phosphoinositides. In Arabidopsis, only one PI3K exists, which belongs to the class-III PI3K subfamily which makes phosphatidylinositol 3-phosphate (PtdIns3P). The single AtPI3K gene is essential for survival, since loss of its

  1. Differential Regulation of Adhesion Complex Turnover by ROCK1 and ROCK2

    OpenAIRE

    Lock, Frances E.; Katie R Ryan; Poulter, Natalie S.; Maddy Parsons; Hotchin, Neil A

    2012-01-01

    BACKGROUND: ROCK1 and ROCK2 are serine/threonine kinases that function downstream of the small GTP-binding protein RhoA. Rho signalling via ROCK regulates a number of cellular functions including organisation of the actin cytoskeleton, cell adhesion and cell migration. METHODOLOGY/PRINCIPAL FINDINGS: In this study we use RNAi to specifically knockdown ROCK1 and ROCK2 and analyse their role in assembly of adhesion complexes in human epidermal keratinocytes. We observe that loss of ROCK1 inhibi...

  2. DDRs: receptors that mediate adhesion, migration and invasion in breast cancer cells

    Directory of Open Access Journals (Sweden)

    Emmanuel Reyes-Uribe

    2015-08-01

    Full Text Available Discoidin domain receptors (DDRs are receptor tyrosine kinases that are activated by native collagens and have an important role during cell adhesion, development, differentiation, proliferation, and migration. DDR deregulation is associated with progression of several different cancers. However, there is limited information about the role of DDRs in the progression of breast cancer. In this review we attempt to collect the most relevant information about DDR signaling and their role in various cancer-related processes such as adhesion, epithelial to mesenchymal transition, migration, invasion, and survival, with a focus on breast cancer.

  3. Proteomic dataset of the sea urchin Paracentrotus lividus adhesive organs and secreted adhesive

    NARCIS (Netherlands)

    Lebesgue, Nicolas; da Costa, Gonçalo; Ribeiro, Raquel Mesquita; Ribeiro-Silva, Cristina; Martins, Gabriel G; Matranga, Valeria; Scholten, Arjen; Cordeiro, Carlos; Heck, Albert J R; Santos, Romana

    2016-01-01

    Sea urchins have specialized adhesive organs called tube feet, which mediate strong but reversible adhesion. Tube feet are composed by a disc, producing adhesive and de-adhesive secretions for substratum attachment, and a stem for movement. After detachment the secreted adhesive remains bound to the

  4. Cardamonin Inhibits Metastasis of Lewis Lung Carcinoma Cells by Decreasing mTOR Activity.

    Directory of Open Access Journals (Sweden)

    Pei-Guang Niu

    Full Text Available The mammalian target of rapamycin (mTOR regulates the motility and invasion of cancer cells. Cardamonin is a chalcone that exhibits anti-tumor activity. The previous study had proved that the anti-tumor effect of cardamonin was associated with mTOR inhibition. In the present study, the anti-metastatic effect of cardamonin and its underlying molecule mechanisms were investigated on the highly metastatic Lewis lung carcinoma (LLC cells. The proliferation, invasion and migration of LLC cells were measured by MTT, transwell and wound healing assays, respectively. The expression and activation of mTOR- and adhesion-related proteins were assessed by Western blotting. The in vivo effect of cardamonin on the metastasis of the LLC cells was investigated by a mouse model. Treated with cardamonin, the proliferation, invasion and migration of LLC cells were significantly inhibited. The expression of Snail was decreased by cardamonin, while that of E-cadherin was increased. In addition, cardamonin inhibited the activation of mTOR and its downstream target ribosomal S6 kinase 1 (S6K1. Furthermore, the tumor growth and its lung metastasis were inhibited by cardamonin in C57BL/6 mice. It indicated that cardamonin inhibited the invasion and metastasis of LLC cells through inhibiting mTOR. The metastasis inhibitory effect of cardamonin was correlated with down-regulation of Snail and up-regulation of E-cadherin.

  5. Optimizing Adhesive Design by Understanding Compliance.

    Science.gov (United States)

    King, Daniel R; Crosby, Alfred J

    2015-12-23

    Adhesives have long been designed around a trade-off between adhesive strength and releasability. Geckos are of interest because they are the largest organisms which are able to climb utilizing adhesive toepads, yet can controllably release from surfaces and perform this action over and over again. Attempting to replicate the hierarchical, nanoscopic features which cover their toepads has been the primary focus of the adhesives field until recently. A new approach based on a scaling relation which states that reversible adhesive force capacity scales with (A/C)(1/2), where A is the area of contact and C is the compliance of the adhesive, has enabled the creation of high strength, reversible adhesives without requiring high aspect ratio, fibrillar features. Here we introduce an equation to calculate the compliance of adhesives, and utilize this equation to predict the shear adhesive force capacity of the adhesive based on the material components and geometric properties. Using this equation, we have investigated important geometric parameters which control force capacity and have shown that by controlling adhesive shape, adhesive force capacity can be increased by over 50% without varying pad size. Furthermore, we have demonstrated that compliance of the adhesive far from the interface still influences shear adhesive force capacity. Utilizing this equation will allow for the production of adhesives which are optimized for specific applications in commercial and industrial settings.

  6. Innovative Electrostatic Adhesion Technologies

    Science.gov (United States)

    Bryan, Tom; Macleod, Todd; Gagliano, Larry; Williams, Scott; McCoy, Brian

    2015-01-01

    Developing specialized Electro-Static grippers (commercially used in Semiconductor Manufacturing and in package handling) will allow gentle and secure Capture, Soft Docking, and Handling of a wide variety of materials and shapes (such as upper-stages, satellites, arrays, and possibly asteroids) without requiring physical features or cavities for a pincher or probe or using harpoons or nets. Combined with new rigid boom mechanisms or small agile chaser vehicles, flexible, high speed Electro-Static Grippers can enable compliant capture of spinning objects starting from a safe stand-off distance. Electroadhesion (EA) can enable lightweight, ultra-low-power, compliant attachment in space by using an electrostatic force to adhere similar and dissimilar surfaces. A typical EA enabled device is composed of compliant space-rated materials, such as copper-clad polyimide encapsulated by polymers. Attachment is induced by strong electrostatic forces between any substrate material, such as an exterior satellite panel and a compliant EA gripper pad surface. When alternate positive and negative charges are induced in adjacent planar electrodes in an EA surface, the electric fields set up opposite charges on the substrate and cause an electrostatic adhesion between the electrodes and the induced charges on the substrate. Since the electrodes and the polymer are compliant and can conform to uneven or rough surfaces, the electrodes can remain intimately close to the entire surface, enabling high clamping pressures. Clamping pressures of more than 3 N/cm2 in shear can be achieved on a variety of substrates with ultra-low holding power consumption (measured values are less than 20 microW/Newton weight held). A single EA surface geometry can be used to clamp both dielectric and conductive substrates, with slightly different physical mechanisms. Furthermore EA clamping requires no normal force be placed on the substrate, as conventional docking requires. Internally funded research and

  7. Innovative Electrostatic Adhesion Technologies

    Science.gov (United States)

    Gagliano, L.; Bryan, T.; Williams, S.; McCoy, B.; MacLeod, T.

    Developing specialized Electro-Static grippers (commercially used in Semiconductor Manufacturing and in package handling) will allow gentle and secure Capture, Soft Docking, and Handling of a wide variety of materials and shapes (such as upper-stages, satellites, arrays, and possibly asteroids) without requiring physical features or cavities for a pincher or probe or using harpoons or nets. Combined with new rigid boom mechanisms or small agile chaser vehicles, flexible, high speed Electro-Static Grippers can enable compliant capture of spinning objects starting from a safe stand-off distance. Electroadhesion (EA) can enable lightweight, ultra-low-power, compliant attachment in space by using an electrostatic force to adhere similar and dissimilar surfaces. A typical EA enabled device is composed of compliant space-rated materials, such as copper-clad polyimide encapsulated by polymers. Attachment is induced by strong electrostatic forces between any substrate material, such as an exterior satellite panel and a compliant EA surface. When alternate positive and negative charges are induced in adjacent planar electrodes in an EA surface, the electric fields set up opposite charges on the substrate and cause an electrostatic adhesion between the electrodes and the induced charges on the substrate. Since the electrodes and the polymer are compliant and can conform to uneven or rough surfaces, the electrodes can remain intimately close to the entire surface, enabling high clamping pressures. Clamping pressures of more than 3 N/cm2 in shear can be achieved on a variety of substrates with ultra-low holding power consumption (measured values are less than 20 microW/Newton weight held). A single EA surface geometry can be used to clamp both dielectric and conductive substrates, with slightly different physical mechanisms. Furthermore EA clamping requires no normal force be placed on the substrate, as conventional docking requires. Internally funded research and development

  8. Adhesion energy, surface traction and surface tension in liquid xenon

    Indian Academy of Sciences (India)

    B Mathew; G A Adebayo

    2011-12-01

    We calculated the adhesion energy, the surface traction and the surface energy of liquid xenon using molecular dynamics (MD) simulation. The value of the adhesion energy for liquid xenon at a reduced density of 0.630 was found to be 0.591 J/m2 and the surface traction has a peak at = 3.32 Å. It was observed that the attraction of the molecules in the liquid surface which produces a resistance to penetration decreases with temperature. This may be attributed to the greater average separation of molecules at higher temperature.

  9. Contribution of casein kinase 2 and spleen tyrosine kinase to CFTR trafficking and protein kinase A-induced activity.

    Science.gov (United States)

    Luz, Simão; Kongsuphol, Patthara; Mendes, Ana Isabel; Romeiras, Francisco; Sousa, Marisa; Schreiber, Rainer; Matos, Paulo; Jordan, Peter; Mehta, Anil; Amaral, Margarida D; Kunzelmann, Karl; Farinha, Carlos M

    2011-11-01

    Previously, the pleiotropic "master kinase" casein kinase 2 (CK2) was shown to interact with CFTR, the protein responsible for cystic fibrosis (CF). Moreover, CK2 inhibition abolished CFTR conductance in cell-attached membrane patches, native epithelial ducts, and Xenopus oocytes. CFTR possesses two CK2 phosphorylation sites (S422 and T1471), with unclear impact on its processing and trafficking. Here, we investigated the effects of mutating these CK2 sites on CFTR abundance, maturation, and degradation coupled to effects on ion channel activity and surface expression. We report that CK2 inhibition significantly decreased processing of wild-type (wt) CFTR, with no effect on F508del CFTR. Eliminating phosphorylation at S422 and T1471 revealed antagonistic roles in CFTR trafficking: S422 activation versus T1471 inhibition, as evidenced by a severe trafficking defect for the T1471D mutant. Notably, mutation of Y512, a consensus sequence for the spleen tyrosine kinase (SYK) possibly acting in a CK2 context adjacent to the common CF-causing defect F508del, had a strong effect on both maturation and CFTR currents, allowing the identification of this kinase as a novel regulator of CFTR. These results reinforce the importance of CK2 and the S422 and T1471 residues for regulation of CFTR and uncover a novel regulation of CFTR by SYK, a recognized controller of inflammation.

  10. Osteoclast-specific inactivation of the Integrin-Linked Kinase (ILK) inhibits bone resorption

    Science.gov (United States)

    Dossa, Tanya; Arabian, Alice; Windle, Jolene J.; Dedhar, Shoukat; Teitelbaum, Steven L.; Ross, F. Patrick; Roodman, G. David; St-Arnaud, René

    2014-01-01

    Bone resorption requires the adhesion of osteoclasts to extracellular matrix (ECM) components, a process mediated by the αvβ3 integrin. Following engagement with the ECM, integrin receptors signal via multiple downstream effectors, including the Integrin-Linked Kinase (ILK). In order to characterize the physiological role of ILK in bone resorption, we generated mice with an osteoclast-specific Ilk gene ablation by mating mice with a floxed Ilk allele with TRAP-Cre transgenic mice. The TRAP-Cre mice specifically excised floxed alleles in osteoclasts, as revealed by crossing them with the ROSA26R reporter strain. Osteoclast-specific Ilk mutant mice appeared phenotypically normal, but histomorphometric analysis of the proximal tibia revealed an increase in bone volume and trabecular thickness. Osteoclast-specific Ilk ablation was associated with an increase in osteoclastogenesis both in vitro and in vivo. However, the mutant osteoclasts displayed a decrease in resorption activity as assessed by reduced pit formation on dentin slices in vitro and decreased serum concentrations of the C-terminal telopeptide of collagen in vivo. Interestingly, compound heterozygous mice in which one allele of Ilk and one allele of the β3 integrin gene were inactivated (ILK+/−; β3+/−) also had increased trabecular thickness, confirming that β3 integrin and Ilk form part of the same genetic cascade. Our results show that ILK is important for the function, but not the differentiation, of osteoclasts. PMID:20564195

  11. Alcohol and polyphenolic grape extract inhibit platelet adhesion in flowing blood

    NARCIS (Netherlands)

    de Lange, DW; Scholman, WLG; Kraaijenhagen, RJ; Akkerman, JWN; van de Wiel, A

    2004-01-01

    Background Moderate and prolonged alcohol consumption has been associated with decreased cardiovascular morbidity and mortality. Inhibition of platelet function in suspension attributes to these effects. Whether alcohol, red wine, or polyphenolic grape extracts (PGE) inhibit platelet adhesion is not

  12. The Phosphoinositide 3-OH Kinase/AKT2 Pathway as a Critical Target for Farnesyltransferase Inhibitor-Induced Apoptosis

    OpenAIRE

    Jiang, Kun; Coppola, Domenico; Crespo, Nichole C.; Nicosia, Santo V.; Hamilton, Andrew D.; Sebti, Said M.; Cheng, Jin Q.

    2000-01-01

    Farnesyltransferase inhibitors (FTIs) represent a novel class of anticancer drugs that exhibit a remarkable ability to inhibit malignant transformation without toxicity to normal cells. However, the mechanism by which FTIs inhibit tumor growth is not well understood. Here, we demonstrate that FTI-277 inhibits phosphatidylinositol 3-OH kinase (PI 3-kinase)/AKT2-mediated growth factor- and adhesion-dependent survival pathways and induces apoptosis in human cancer cells that overexpress AKT2. Fu...

  13. Prostate Cancer Cell Growth: Stimulatory Role of Neurotensin and Mechanism of Inhibition by Flavonoids as Related to Protein Kinase C

    Science.gov (United States)

    2010-01-01

    contribute to the malignant state [61–63]. In a prior study [28], we found that NTstimulates PC3 cells to release HB -EGF, which presumably transactivates...growth factor EGFR, EGF receptor ERK, extracellular signal-regulated kinase FAK, focal adhesion kinase GPCR, G protein-coupled receptor Hb -EGF, heparin...al. reported that levels of NT but not CCK (measured by immunoassay ) in fasted sera from patients with pancreatic cancer were significantly elevated in

  14. Assessing the impact of modifications neoprene adhesives amine-containing compounds the mechanisms to improve adhesion

    OpenAIRE

    KABLOV V.F.; KEYBAL N.A.; S. N. Bondarenko; RUDENKO K.U.; Zaikov, G. E.

    2015-01-01

    Possible mechanisms for an increase in the adhesion parameters of neopren-based adhesive compositions modified with adhesion promoters on the basis of epoxy compounds and aniline derivatives are studied.

  15. Capillarity-based switchable adhesion.

    Science.gov (United States)

    Vogel, Michael J; Steen, Paul H

    2010-02-23

    Drawing inspiration from the adhesion abilities of a leaf beetle found in nature, we have engineered a switchable adhesion device. The device combines two concepts: The surface tension force from a large number of small liquid bridges can be significant (capillarity-based adhesion) and these contacts can be quickly made or broken with electronic control (switchable). The device grabs or releases a substrate in a fraction of a second via a low-voltage pulse that drives electroosmotic flow. Energy consumption is minimal because both the grabbed and released states are stable equilibria that persist with no energy added to the system. Notably, the device maintains the integrity of an array of hundreds to thousands of distinct interfaces during active reconfiguration from droplets to bridges and back, despite the natural tendency of the liquid toward coalescence. We demonstrate the scaling of adhesion strength with the inverse of liquid contact size. This suggests that strengths approaching those of permanent bonding adhesives are possible as feature size is scaled down. In addition, controllability is fast and efficient because the attachment time and required voltage also scale down favorably. The device features compact size, no solid moving parts, and is made of common materials.

  16. Polyurethane adhesives in flat roofs

    Directory of Open Access Journals (Sweden)

    Bogárová Markéta

    2017-01-01

    Full Text Available It is necessary to stabilize individual layers of flat roofs, mainly because of wind suction. Apart from anchoring and surcharge, these layers can be secured by bonding. At present gluing is an indispensable and widely used stabilization method. On our market we can found many types of adhesives, most widely used are based on polyurethane. This paper focuses on problematic about stabilization thermal insulation from expanded polystyrene to vapor barrier from bitumen. One of the main issues is to calculate the exact amount of adhesive, which is required to guarantee the resistance against wind suction. In this problematic we can not find help neither in technical data sheets provided by the manufactures. Some of these data sheets contain at least information about amount of adhesive depending on location in roof plane and building height, but they do not specify the strength of such connection. It was therefore resorted to select several representatives polyurethane adhesives and their subsequent testing on specimens simulating the flat roof segment. The paper described the test methodology and results for two types of polyurethane adhesives.

  17. Quantitative comparison of cancer and normal cell adhesion using organosilane monolayer templates: an experimental study on the anti-adhesion effect of green-tea catechins.

    Science.gov (United States)

    Sakamoto, Rumi; Kakinuma, Eisuke; Masuda, Kentaro; Takeuchi, Yuko; Ito, Kosaku; Iketaki, Kentaro; Matsuzaki, Takahisa; Nakabayashi, Seiichiro; Yoshikawa, Hiroshi Y; Yamamoto, Hideaki; Sato, Yuko; Tanii, Takashi

    2016-09-01

    The main constituent of green tea, (-)-Epigallocatechin-3-O-gallate (EGCG), is known to have cancer-specific chemopreventive effects. In the present work, we investigated how EGCG suppresses cell adhesion by comparing the adhesion of human pancreatic cancer cells (AsPC-1 and BxPC-3) and their counterpart, normal human embryonic pancreas-derived cells (1C3D3), in catechin-containing media using organosilane monolayer templates (OMTs). The purpose of this work is (1) to evaluate the quantitativeness in the measurement of cell adhesion with the OMT and (2) to show how green-tea catechins suppress cell adhesion in a cancer-specific manner. For the first purpose, the adhesion of cancer and normal cells was compared using the OMT. The cell adhesion in different type of catechins such as EGCG, (-)-Epicatechin-3-O-gallate (ECG) and (-)-Epicatechin (EC) was also evaluated. The measurements revealed that the anti-adhesion effect of green-tea catechins is cancer-specific, and the order is EGCG≫ECG>EC. The results agree well with the data reported to date, showing the quantitativeness of the new method. For the second purpose, the contact area of cells on the OMT was measured by reflection interference contrast microscopy. The cell-OMT contact area of cancer cells decreases with increasing EGCG concentration, whereas that of normal cells remains constant. The results reveal a twofold action of EGCG on cancer cell adhesion-suppressing cell attachment to a candidate adhesion site and decreasing the contact area of the cells-and validates the use of OMT as a tool for screening cancer cell adhesion.

  18. Tyrosine kinases in rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    Kobayashi Akiko

    2011-08-01

    Full Text Available Abstract Rheumatoid arthritis (RA is an inflammatory, polyarticular joint disease. A number of cellular responses are involved in the pathogenesis of rheumatoid arthritis, including activation of inflammatory cells and cytokine expression. The cellular responses involved in each of these processes depends on the specific signaling pathways that are activated; many of which include protein tyrosine kinases. These pathways include the mitogen-activated protein kinase pathway, Janus kinases/signal transducers and activators transcription pathway, spleen tyrosine kinase signaling, and the nuclear factor κ-light-chain-enhancer of activated B cells pathway. Many drugs are in development to target tyrosine kinases for the treatment of RA. Based on the number of recently published studies, this manuscript reviews the role of tyrosine kinases in the pathogenesis of RA and the potential role of kinase inhibitors as new therapeutic strategies of RA.

  19. Influence of subinhibitory concentrations of cefotaxime, imipenem and ciprofloxacin on adhesion of Escherichia coli strains to polystyrene.

    Science.gov (United States)

    Zalas-Wiecek, Patrycja; Gospodarek, Eugenia; Piecyk, Katarzyna

    2011-01-01

    The present study investigated the ability of sub MICs of cefotaxime, imipenem and ciprofloxacin to interfere with adhesion of E. coli strains to polystyrene (selected polymer used in studies on microorganisms' adhesion). It was observed that cefotaxime and imipenem at 1/2 and 1/4 MICs decreased the adherence of E. coli strains to polystyrene significantly. 1/2, 1/4 and 1/8 MICs of ciprofloxacin generally decreased the adhesive properties of E. coli strains, but two E. coli strains showed a noticeable enhancement of adhesion after incubation at sub MICs of this antibiotic.

  20. Adhesive application method in MDI-UF particleboard manufacture

    Institute of Scientific and Technical Information of China (English)

    Wang Weihong; Zhang Xianquan; Lu Renshu

    2006-01-01

    Chinese wood-based composite manufacturers,are plagued with serious formaldehyde emission (F-emisslon)problems.In this study,we investigated the use of an emulsifiable diphenylmethane-4,4'-diisocyanate (MDI) -urea formaldehyde (UF) mixture adhesive in particleboard manufacture,in order to decrease F-emission to below 9 mg per 100 g board.We paid close attention to the effect of NH4C1 on MDI-UF curing and the method of adhesive application by differential scanning calorimetric (DSC)analysis and compared mechanical properties.Both results showed that the acidic agent NH4C1 did hinder EMDI-UF curing and it also affected the adhesive application method.We are of the opinion that when EMDI and UF are mixed first,without adding NH4C1 and then sprayed onto particles,mechanical properties will be improved and F-emissions will meet E1 grade requirements.

  1. Adhesiveness of cold rolled steels for car body parts

    Directory of Open Access Journals (Sweden)

    Kleiner Marques Marra

    2007-09-01

    Full Text Available The aim of this work was to evaluate the adhesiveness of uncoated and zinc-electrogalvanized steel sheets used in the automotive industry. Three types of adhesives, one acrylic and two epoxy resins, were employed to join low carbon cold rolled steels, one uncoated and another electrogalvanized, both previously degreased or chemically pickled. Mechanical strength of the joints was evaluated by the T-peel and tensile strength tests. Steel grade, surface condition and heating below the cure temperatures did not influence the joints' mechanical strength. However, their shear strength decreased drastically as the test temperature increased. The exposure of the joints to an atmosphere with 90% relative humidity at 40 °C caused reduction of their shear strength. Epoxy adhesives showed higher mechanical strength, but exhibited higher degradation by humidity.

  2. Strong adhesion in nanocrystalline diamond films on silicon substrates

    Science.gov (United States)

    Sharda, T.; Umeno, M.; Soga, T.; Jimbo, T.

    2001-05-01

    Strong adhesion is shown to be achieved in the growth of smooth nanocrystalline diamond (NCD) thin films on silicon substrates at 600 °C using biased enhanced growth in microwave plasma chemical vapor deposition. The strong adhesion is evident from the films sustaining compressive stress, which may be as high as 85 GPa. The substrates are bent spherically after deposition, however, films are not peeled off, in spite of having enormous in-plane stress. The strong adhesion may be a result of implanted carbon below the substrate surface with an optimized ion flux density in the initial stages of growth. The compressive stress in the films is shown to be generating from the graphitic and other nondiamond carbon impurities in the films. It was observed that the NCD grain size decreases with biasing hence increasing grain boundary area in the films accommodating more graphitic impurities, which in turn results in an increase in compressive stress in the films.

  3. Enterococcus faecalis phosphomevalonate kinase

    OpenAIRE

    Doun, Stephanie S.; Burgner, John W.; Briggs, Scott D.; Rodwell, Victor W.

    2005-01-01

    The six enzymes of the mevalonate pathway of isopentenyl diphosphate biosynthesis represent potential for addressing a pressing human health concern, the development of antibiotics against resistant strains of the Gram-positive streptococci. We previously characterized the first four of the mevalonate pathway enzymes of Enterococcus faecalis, and here characterize the fifth, phosphomevalonate kinase (E.C. 2.7.4.2). E. faecalis genomic DNA and the polymerase chain reaction were used to clone D...

  4. Oncoprotein protein kinase

    Energy Technology Data Exchange (ETDEWEB)

    Karin, Michael (San Diego, CA); Hibi, Masahiko (San Diego, CA); Lin, Anning (La Jolla, CA); Davis, Roger (Princeton, MA); Derijard, Benoit (Shrewsbury, MA)

    2003-02-04

    An isolated polypeptide (JNK) characterized by having a molecular weight of 46kD as determined by reducing SDS-PAGE, having serine and threonine kinase activity, phosphorylating the c-Jun N-terminal activation domain and polynucleotide sequences and method of detection of JNK are provided herein. JNK phosphorylates c-Jun N-terminal activation domain which affects gene expression from AP-1 sites.

  5. Cell adhesion in embryo morphogenesis.

    Science.gov (United States)

    Barone, Vanessa; Heisenberg, Carl-Philipp

    2012-02-01

    Visualizing and analyzing shape changes at various scales, ranging from single molecules to whole organisms, are essential for understanding complex morphogenetic processes, such as early embryonic development. Embryo morphogenesis relies on the interplay between different tissues, the properties of which are again determined by the interaction between their constituent cells. Cell interactions, on the other hand, are controlled by various molecules, such as signaling and adhesion molecules, which in order to exert their functions need to be spatiotemporally organized within and between the interacting cells. In this review, we will focus on the role of cell adhesion functioning at different scales to organize cell, tissue and embryo morphogenesis. We will specifically ask how the subcellular distribution of adhesion molecules controls the formation of cell-cell contacts, how cell-cell contacts determine tissue shape, and how tissue interactions regulate embryo morphogenesis.

  6. Adhesion properties of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based adhesives in the presence of phenol formaldehyde resin

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available The adhesion properties, i. e. viscosity, tack and peel strength of styrene-butadiene rubber (SBR/Standard Malaysian Rubber (SMR L-based pressure-sensitive adhesive was studied using phenol formaldehyde resin as the tackifying resin. Toluene was used as the solvent throughout the experiment. SBR composition in SBR/SMR L blend used was 0, 20, 40, 60, 80, 100%. Three different resin loadings, i. e. 40, 80 and 120 parts per hundred parts of rubber (phr were used in the adhesive formulation. The viscosity of adhesive was determined by a HAAKE Rotary Viscometer whereas loop tack and peel strength of paper/polyethylene terephthalate (PET film were measured using a Lloyd Adhesion Tester operating at 30 cm/min. Results indicate that the viscosity of adhesive decreases with increasing % SBR whereas loop tack passes through a maximum value at 20% SBR for all resin loadings. Except for the control sample (without resin, the peel strength shows a maximum value at 60% SBR for the three modes of peel tests. For a fixed % SBR, adhesive sample containing 40 phr phenol formaldehyde resin always exhibits the highest loop tack and peel strength, an observation which is associated to the optimum wettability of adhesive on the substrate.

  7. The conveyor belt hypothesis for thymocyte migration: participation of adhesion and de-adhesion molecules

    Directory of Open Access Journals (Sweden)

    Villa-Verde D.M.S.

    1999-01-01

    Full Text Available Thymocyte differentiation is the process by which bone marrow-derived precursors enter the thymus, proliferate, rearrange the genes and express the corresponding T cell receptors, and undergo positive and/or negative selection, ultimately yielding mature T cells that will represent the so-called T cell repertoire. This process occurs in the context of cell migration, whose cellular and molecular basis is still poorly understood. Kinetic studies favor the idea that these cells leave the organ in an ordered pattern, as if they were moving on a conveyor belt. We have recently proposed that extracellular matrix glycoproteins, such as fibronectin, laminin and type IV collagen, among others, produced by non-lymphoid cells both in the cortex and in the medulla, would constitute a macromolecular arrangement allowing differentiating thymocytes to migrate. Here we discuss the participation of both molecules with adhesive and de-adhesive properties in the intrathymic T cell migration. Functional experiments demonstrated that galectin-3, a soluble ß-galactoside-binding lectin secreted by thymic microenvironmental cells, is a likely candidate for de-adhesion proteins by decreasing thymocyte interaction with the thymic microenvironment.

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

    Science.gov (United States)

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

    2006-10-01

    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 beta1-integrin in the cell area contacting the substrate. In this study, we isolated additional antisense-Dp71 clones to analyze in detail the potential involvement of Dp71f isoform with the beta1-integrin adhesion system of PC12 cells. Immunofluorescence analyses as well as immunoprecipitation assays demonstrated that the PC12 cell beta1-integrin adhesion complex is composed of beta1-integrin, talin, paxillin, alpha-actinin, FAK and actin. In addition, our results showed that Dp71f associates with most of the beta1-integrin complex components (beta1-integrin, FAK, alpha-actinin, talin and actin). In the antisense-Dp71 cells, the deficiency of Dp71 provokes a significant reduction of the beta1-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 beta1-integrin. Our data indicate that Dp71f is a structural component of the beta1-integrin adhesion complex of PC12 cells that modulates PC12 cell adhesion by conferring proper complex assembly and/or maintenance.

  9. Switchable Dry Adhesion with Step-like Micropillars and Controllable Interfacial Contact.

    Science.gov (United States)

    Wang, Yue; Tian, Hongmiao; Shao, Jinyou; Sameoto, Dan; Li, Xiangming; Wang, Li; Hu, Hong; Ding, Yucheng; Lu, Bingheng

    2016-04-20

    Dry adhesives have attracted much attention because of their repeatable and reversible attachment. Many research groups have made fruitful achievements in fabricating and designing various dry adhesives. However, most of these studies focus on imitating bioinspired geometry to achieve this smart adhesion, neglecting the contact interface control through their peeling motion. Here, we present an alternative design to achieve this switchable adhesion on the basis of controlling contact areas. This unique design includes micropillars array with large overhanging caps and a "step" located at the center line of the cap. When dragging the pillars in the direction of the upper surface of the step, the lower surface is brought into contact, rapidly yielding stronger adhesion (switched-on state). Alternatively, when dragging the pillars in the direction of the lower surface of the step, the contact areas decrease sharply, leading to weak adhesion (switched-off state). Such switchable property under strong adhesion force is exactly what many practical applications need, and the ability to achieve this property by controlling the adhesion area size presented here opens a new way to dry adhesives design.

  10. The Influence of Biochemical Modification on the Properties of Adhesive Compounds

    Directory of Open Access Journals (Sweden)

    Anna Rudawska

    2016-12-01

    Full Text Available The main objective of this study was to determine the effect of biochemical modification of epoxy adhesive compounds on the mechanical properties of a cured adhesive exposed to various climatic factors. The epoxy adhesive was modified by lyophilized fungal metabolites and prepared by three methods. Additionally, the adhesive compound specimens were seasoned for two months at a temperature of 50 °C and 50% humidity in a climate test chamber, Espec SH 661. The tensile strength tests of the adhesive compounds were performed using a Zwick/Roell Z150 testing machine in compliance with the DIN EN ISO 527-1 standard. The examination of the adhesive specimens was performed using two microscopes: a LEO 912AB transmission electron microscope equipped with Quantax 200 for EDS X-ray spectroscopy and a Zeiss 510 META confocal microscope coupled to an AxioVert 200M. The experiments involved the use of a CT Skyscan 1172 tomograph. The results revealed that some mechanical properties of the modified adhesives were significantly affected by both the method of preparation of the adhesive compound and the content of the modifying agent. In addition, it was found that seasoning of the modified adhesives does not lead to a decrease in some of their mechanical properties.

  11. Hydrostatic Compress Force Enhances the Viability and Decreases the Apoptosis of Condylar Chondrocytes through Integrin-FAK-ERK/PI3K Pathway

    Science.gov (United States)

    Ma, Dandan; Kou, Xiaoxing; Jin, Jing; Xu, Taotao; Wu, Mengjie; Deng, Liquan; Fu, Lusi; Liu, Yi; Wu, Gang; Lu, Haiping

    2016-01-01

    Reduced mechanical stimuli in many pathological cases, such as hemimastication and limited masticatory movements, can significantly affect the metabolic activity of mandibular condylar chondrocytes and the growth of mandibles. However, the molecular mechanisms for these phenomena remain unclear. In this study, we hypothesized that integrin-focal adhesion kinase (FAK)-ERK (extracellular signal–regulated kinase)/PI3K (phosphatidylinositol-3-kinase) signaling pathway mediated the cellular response of condylar chondrocytes to mechanical loading. Primary condylar chondrocytes were exposed to hydrostatic compressive forces (HCFs) of different magnitudes (0, 50, 100, 150, 200, and 250 kPa) for 2 h. We measured the viability, morphology, and apoptosis of the chondrocytes with different treatments as well as the gene, protein expression, and phosphorylation of mechanosensitivity-related molecules, such as integrin α2, integrin α5, integrin β1, FAK, ERK, and PI3K. HCFs could significantly increase the viability and surface area of condylar chondrocytes and decrease their apoptosis in a dose-dependent manner. HCF of 250 kPa resulted in a 1.51 ± 0.02-fold increase of cell viability and reduced the ratio of apoptotic cells from 18.10% ± 0.56% to 7.30% ± 1.43%. HCFs could significantly enhance the mRNA and protein expression of integrin α2, integrin α5, and integrin β1 in a dose-dependent manner, but not ERK1, ERK2, or PI3K. Instead, HCF could significantly increase phosphorylation levels of FAK, ERK1/2, and PI3K in a dose-dependent manner. Cilengitide, the potent integrin inhibitor, could dose-dependently block such effects of HCFs. HCFs enhances the viability and decreases the apoptosis of condylar chondrocytes through the integrin-FAK-ERK/PI3K pathway. PMID:27827993

  12. Developing Strategies to Block Beta-Catenin Action in Signaling and Cell Adhesion During Carcinogenesis

    Science.gov (United States)

    2002-07-01

    Chapel Hill NC July, 2001 "Cell adhesion, signal transduction, and cancer: the Armadillo Connection." Department of Embryology , Carnegie Institution...Published online May 30, 2001 Copyright © 2001 by Academic Prcss. All rights of reproduction in any form rescrved. Article Abelson kinase regulates epithelial...in APC2 divisions, when astral microtubules are prominent during late mutants: (1 ) abnormal mitoses owing to pseudocleavage furrow mitosis (Fig. 3i,j

  13. Microtubules Inhibit E-Cadherin Adhesive Activity by Maintaining Phosphorylated p120-Catenin in a Colon Carcinoma Cell Model.

    Directory of Open Access Journals (Sweden)

    Stephanie L Maiden

    Full Text Available Tight regulation of cadherin-mediated intercellular adhesions is critical to both tissue morphogenesis during development and tissue homeostasis in adults. Cell surface expression of the cadherin-catenin complex is often directly correlated with the level of adhesion, however, examples exist where cadherin appears to be inactive and cells are completely non-adhesive. The state of p120-catenin phosphorylation has been implicated in regulating the adhesive activity of E-cadherin but the mechanism is currently unclear. We have found that destabilization of the microtubule cytoskeleton, independent of microtubule plus-end dynamics, dephosphorylates p120-catenin and activates E-cadherin adhesion in Colo 205 cells. Through chemical screening, we have also identified several kinases as potential regulators of E-cadherin adhesive activity. Analysis of several p120-catenin phosphomutants suggests that gross dephosphorylation of p120-catenin rather than that of specific amino acids may trigger E-cadherin adhesion. Uncoupling p120-catenin binding to E-cadherin at the membrane causes constitutive adhesion in Colo 205 cells, further supporting an inhibitory role of phosphorylated p120-catenin on E-cadherin activity.

  14. Microtubules Inhibit E-Cadherin Adhesive Activity by Maintaining Phosphorylated p120-Catenin in a Colon Carcinoma Cell Model.

    Science.gov (United States)

    Maiden, Stephanie L; Petrova, Yuliya I; Gumbiner, Barry M

    2016-01-01

    Tight regulation of cadherin-mediated intercellular adhesions is critical to both tissue morphogenesis during development and tissue homeostasis in adults. Cell surface expression of the cadherin-catenin complex is often directly correlated with the level of adhesion, however, examples exist where cadherin appears to be inactive and cells are completely non-adhesive. The state of p120-catenin phosphorylation has been implicated in regulating the adhesive activity of E-cadherin but the mechanism is currently unclear. We have found that destabilization of the microtubule cytoskeleton, independent of microtubule plus-end dynamics, dephosphorylates p120-catenin and activates E-cadherin adhesion in Colo 205 cells. Through chemical screening, we have also identified several kinases as potential regulators of E-cadherin adhesive activity. Analysis of several p120-catenin phosphomutants suggests that gross dephosphorylation of p120-catenin rather than that of specific amino acids may trigger E-cadherin adhesion. Uncoupling p120-catenin binding to E-cadherin at the membrane causes constitutive adhesion in Colo 205 cells, further supporting an inhibitory role of phosphorylated p120-catenin on E-cadherin activity.

  15. Dependence of Adhesion Property of Epoxidized Natural Rubber (ENR 25/Ethylene-Propylene-Diene Rubber Blend Adhesives Crosslinked by Benzoyl Peroxide

    Directory of Open Access Journals (Sweden)

    B. T. Poh

    2014-01-01

    Full Text Available The loop tack, peel strength, and shear strength of crosslinked epoxidized natural rubber (ENR 25/ethylene-propylene-diene rubber (EPDM blend adhesives were investigated. Coumarone-indene resin, toluene, and benzoyl peroxide were used as the tackifier, solvent, and crosslinking agent, respectively, throughout the experiment. The adhesive was coated on a polyethylene terephthalate (PET substrate using a SHEEN hand coater at 60 μm and 120 μm coating thickness. It was cured at 80°C for 30 minutes before testing on a Lloyd adhesion tester operating at testing rates from 10 to 60 cm min−1. Results show that loop tack and peel strength of the ENR 25/EPDM adhesive pass through a maximum value at 2 parts per hundred parts of rubber (phr of benzoyl peroxide content. This observation is attributed to the increase in crosslinking which enhances the cohesive strength of the adhesive. Further addition of the crosslinking agent decreases the tack and peel strength due to the decrease in wettability of the over-crosslinked adhesive. Shear strength, however, increases steadily with benzoyl peroxide content, an observation which is associated with the steady increase in the cohesive strength. The adhesion properties increase with increasing coating thickness and testing rate.

  16. Regulation of Autophagy by Kinases

    Energy Technology Data Exchange (ETDEWEB)

    Sridharan, Savitha; Jain, Kirti; Basu, Alakananda, E-mail: alakananda.basu@unthsc.edu [Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, TX 76107 (United States)

    2011-06-09

    Autophagy is a process of self-degradation that maintains cellular viability during periods of metabolic stress. Although autophagy is considered a survival mechanism when faced with cellular stress, extensive autophagy can also lead to cell death. Aberrations in autophagy are associated with several diseases, including cancer. Therapeutic exploitation of this process requires a clear understanding of its regulation. Although the core molecular components involved in the execution of autophagy are well studied there is limited information on how cellular signaling pathways, particularly kinases, regulate this complex process. Protein kinases are integral to the autophagy process. Atg1, the first autophagy-related protein identified, is a serine/threonine kinase and it is regulated by another serine/threonine kinase mTOR. Emerging studies suggest the participation of many different kinases in regulating various components/steps of this catabolic process. This review focuses on the regulation of autophagy by several kinases with particular emphasis on serine/threonine protein kinases such as mTOR, AMP-activated protein kinase, Akt, mitogen-activated protein kinase (ERK, p38 and JNK) and protein kinase C that are often deregulated in cancer and are important therapeutic targets.

  17. Interfacial Friction and Adhesion of Polymer Brushes

    KAUST Repository

    Landherr, Lucas J. T.

    2011-08-02

    A bead-probe lateral force microscopy (LFM) technique is used to characterize the interfacial friction and adhesion properties of polymer brushes. Our measurements attempt to relate the physical structure and chemical characteristics of the brush to their properties as thin-film, tethered lubricants. Brushes are synthesized at several chain lengths and surface coverages from polymer chains of polydimethylsiloxane (PDMS), polystyrene (PS), and a poly(propylene glycol)-poly(ethylene glycol) block copolymer (PPG/PEG). At high surface coverage, PDMS brushes manifest friction coefficients (COFs) that are among the lowest recorded for a dry lubricant film (μ ≈ 0.0024) and close to 1 order of magnitude lower than the COF of a bare silicon surface. Brushes synthesized from higher molar mass chains exhibit higher friction forces than those created using lower molar mass polymers. Increased grafting density of chains in the brush significantly reduces the COF by creating a uniform surface of stretched chains with a decreased surface viscosity. Brushes with lower surface tension and interfacial shear stresses manifest the lowest COF. In particular, PDMS chains exhibit COFs lower than PS by a factor of 3.7 and lower than PPG/PEG by a factor of 4.7. A scaling analysis conducted on the surface coverage (δ) in relation to the fraction (ε) of the friction force developing from adhesion predicts a universal relation ε ∼ δ4/3, which is supported by our experimental data. © 2011 American Chemical Society.

  18. p38 signaling and receptor recycling events in a microfluidic endothelial cell adhesion assay.

    Directory of Open Access Journals (Sweden)

    Dwayne A L Vickers

    Full Text Available Adhesion-based microfluidic cell separation has proven to be very useful in applications ranging from cancer diagnostics to tissue engineering. This process involves functionalizing microchannel surfaces with a capture molecule. High specificity and purity capture can be achieved using this method. Despite these advances, little is known about the mechanisms that govern cell capture within these devices and their relationships to basic process parameters such as fluid shear stress and the presence of soluble factors. This work examines how the adhesion of human endothelial cells (ECs is influenced by a soluble tetrapeptide, Arg-Glu-Asp-Val (REDV and fluidic shear stress. The ability of these ECs to bind within microchannels coated with REDV is shown to be governed by shear- and soluble-factor mediated changes in p38 mitogen-activated protein kinase expression together with recycling of adhesion receptors from the endosome.

  19. Computational Chemistry of Adhesive Bonds

    Science.gov (United States)

    Phillips, Donald H.

    1999-01-01

    This investigation is intended to determine the electrical mechanical, and chemical properties of adhesive bonds at the molecular level. The initial determinations will be followed by investigations of the effects of environmental effects on the chemistry and properties of the bond layer.

  20. Polymer Claw: Instant Underwater Adhesive

    Science.gov (United States)

    2012-10-23

    surface. The amine reacts with the sticky, isocyanate putty to form a tough polyurea. The catalyzed isocyanates likewise bond with alcohols, amines, acids...the metal bristles and displaces the gel to make way for the adhesive. The entire system will be sealed in disposable packaging for safe storage and

  1. Foreign material in postoperative adhesions

    NARCIS (Netherlands)

    R.W. Luijendijk; D.C.D. de Lange (Diederik); C.C. Wauters; W.C.J. Hop (Wim); J.J. Duron; J.L. Pailler; B.R. Camprodon; L. Holmdahl; H.J. van Geldorp; J. Jeekel (Hans)

    1996-01-01

    textabstractOBJECTIVE: The authors determined the prevalence of foreign body granulomas in intra-abdominal adhesions in patients with a history of abdominal surgery. PATIENTS AND METHODS: In a cross-sectional, multicenter, multinational study, adult patients with a hist

  2. Creep behaviour of flexible adhesives

    NARCIS (Netherlands)

    Straalen, IJ.J. van; Botter, E.; Berg, A. van den; Beers, P. van

    2004-01-01

    Since flexible adhesives are used more and more in structural applications, designers should have a better understanding of its behaviour under various conditions as ultimate load, fatigue load, long-term load and environmental conditions. This paper focuses on long-term load conditions and its effe

  3. Tackifier Dispersions to Make Pressure Sensitive Adhesives

    Energy Technology Data Exchange (ETDEWEB)

    None

    2003-02-01

    Development of new processes for tackifier dispersion could improve the production of pressure sensitive adhesives. Pressure sensitive adhesives (PSAs) have the ability to adhere to different surfaces with manual or finger pressure.

  4. Adhesion of Antireflective Coatings in Multijunction Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Brock, Ryan; Miller, David C.; Dauskardt, Reinhold H.

    2016-11-21

    The development of a new composite dual cantilever beam (cDCB) thin-film adhesion testing method is reported, which allows the measurement of adhesion on the fragile thin substrates used in multijunction photovoltaics. We address the adhesion of several antireflective coating systems on multijunction cells. By varying interface chemistry and morphology, we demonstrate the ensuing effects on adhesion and help to develop an understanding of how high adhesion can be achieved, as adhesion values ranging from 0.5 J/m2 to 10 J/m2 were measured. Damp Heat (85 degrees C/85% RH) was used to invoke degradation of interfacial adhesion. We show that even with germanium substrates that fracture easily, quantitative measurements of adhesion can still be made at high test yield. The cDCB test is discussed as an important new methodology, which can be broadly applied to any system that makes use of thin, brittle, or otherwise fragile substrates.

  5. Adhesion of biocompatible and biodegradable micropatterned surfaces

    NARCIS (Netherlands)

    Kaiser, J.S.; Kamperman, M.M.G.; Souza, E.J.; Schick, B.; Arzt, E.

    2011-01-01

    We studied the effects of pillar dimensions and stiffness of biocompatible and biodegradable micropatterned surfaces on adhesion on different compliant substrates. The micropatterned adhesives were based on biocompatible polydimethylsiloxane (PDMS) and biodegradable poly(lactic-co-glycolic) acid (PL

  6. A kinase inhibitor screen identifies Mcl-1 and Aurora kinase A as novel treatment targets in antiestrogen-resistant breast cancer cells

    DEFF Research Database (Denmark)

    Thrane, S; Pedersen, A M; Thomsen, M B H;

    2015-01-01

    of the anti-apoptotic protein Mcl-1. Mcl-1 expression was found upregulated in the antiestrogen-resistant cell lines and depletion of Mcl-1 in resistant cells caused decreased viability. JNJ-7706621, a dual Aurora kinase and cyclin-dependent kinase inhibitor, specifically inhibited growth and caused G2 phase...

  7. The Role of the Electrostatic Force in Spore Adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Eunhyea [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Lee, Ida [University of Tennessee, Knoxville (UTK); Tsouris, Costas [ORNL

    2010-01-01

    Electrostatic force is investigated as one of the components of the adhesion force between Bacillus thuringiensis (Bt) spores and planar surfaces. The surface potentials of a Bt spore and a mica surface are experimentally obtained using a combined atomic force microscopy (AFM)-scanning surface potential microscopy technique. On the basis of experimental information, the surface charge density of the spores is estimated at 0.03 {micro}C/cm{sup 2} at 20% relative humidity and decreases with increasing humidity. The Coulombic force is introduced for the spore-mica system (both charged, nonconductive surfaces), and an electrostatic image force is introduced to the spore-gold system because gold is electrically conductive. The Coulombic force for spore-mica is repulsive because the components are similarly charged, while the image force for the spore-gold system is attractive. The magnitude of both forces decreases with increasing humidity. The electrostatic forces are added to other force components, e.g., van der Waals and capillary forces, to obtain the adhesion force for each system. The adhesion forces measured by AFM are compared to the estimated values. It is shown that the electrostatic (Coulombic and image) forces play a significant role in the adhesion force between spores and planar surfaces.

  8. Morphology and contact mechanics influence adhesive characteristics of Dung Beetle's bristle and Gecko's setae

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Geckos (Gekko gecko) use their hairy setae to adhere on various solid surfaces and dung beetles ( Copris ochus Motschulsky) use their hairy bristles to anti-adhere in sticky environments. We study why two hairy systems express a conflict in functions by using SEM, histological approaches and functional experiments. Adhesion models and various parameters were collected and analyzed. Based on the morphological data and functional experimental results carried out by natural and denatured gecko setae and beetle bristles, we first demonstrated that the stiffness along the hair is 1000 to 30000 times that perpendicular to the hair. This stiffness difference is the key factor leading to the two hairy systems' functional differences. Slope of gecko setae reduces contact stiffness, increases contact points and real contact area that results in amazing adhesive abilities. On the other hand, stiff bristles in a beetle have higher contact stiffness, which reduces the real contact area and decreases the adhesion between two contact surfaces. Deformation of gecko setae destroys the hierarchical structure, increases the contact stiffness and results in a decrease of adhesion forces. Similarly, deformation of beetle bristles destroys the erect structure of the hair, interconnects the separated bristles and thus decreases the anti-adhesive functions. These observations inspire us in designing anti-adhesive and adhesive biomimetic systems.

  9. A dual role for integrin-linked kinase and β1-integrin in modulating cardiac aging.

    Science.gov (United States)

    Nishimura, Mayuko; Kumsta, Caroline; Kaushik, Gaurav; Diop, Soda B; Ding, Yun; Bisharat-Kernizan, Jumana; Catan, Hannah; Cammarato, Anthony; Ross, Robert S; Engler, Adam J; Bodmer, Rolf; Hansen, Malene; Ocorr, Karen

    2014-06-01

    Cardiac performance decreases with age, which is a major risk factor for cardiovascular disease and mortality in the aging human population, but the molecular mechanisms underlying cardiac aging are still poorly understood. Investigating the role of integrin-linked kinase (ilk) and β1-integrin (myospheroid, mys) in Drosophila, which colocalize near cardiomyocyte contacts and Z-bands, we find that reduced ilk or mys function prevents the typical changes of cardiac aging seen in wildtype, such as arrhythmias. In particular, the characteristic increase in cardiac arrhythmias with age is prevented in ilk and mys heterozygous flies with nearly identical genetic background, and they live longer, in line with previous findings in Caenorhabditis elegans for ilk and in Drosophila for mys. Consistent with these findings, we observed elevated β1-integrin protein levels in old compared with young wild-type flies, and cardiac-specific overexpression of mys in young flies causes aging-like heart dysfunction. Moreover, moderate cardiac-specific knockdown of integrin-linked kinase (ILK)/integrin pathway-associated genes also prevented the decline in cardiac performance with age. In contrast, strong cardiac knockdown of ilk or ILK-associated genes can severely compromise cardiac integrity, including cardiomyocyte adhesion and overall heart function. These data suggest that ilk/mys function is necessary for establishing and maintaining normal heart structure and function, and appropriate fine-tuning of this pathway can retard the age-dependent decline in cardiac performance and extend lifespan. Thus, ILK/integrin-associated signaling emerges as an important and conserved genetic mechanism in longevity, and as a new means to improve age-dependent cardiac performance, in addition to its vital role in maintaining cardiac integrity.

  10. Phosphatidylinositol 3-kinase in myogenesis.

    Science.gov (United States)

    Kaliman, P; Zorzano, A

    1997-08-01

    Phosphatidylinositol 3-kinase (PI 3-kinase) has been cloned and characterized in a wide range of organisms. PI 3-kinases are activated by a diversity of extracellular stimuli and are involved in multiple cell processes such as cell proliferation, protein trafficking, cell motility, differentiation, regulation of cytoskeletal structure, and apoptosis. It has recently been shown that PI 3-kinase is a crucial second messenger in the signaling of myogenesis. Two structurally unrelated highly specific inhibitors of PI 3-kinase-wortmannin and LY294002-block the morphological and biochemical differentiation program of different skeletal-muscle cell models. Moreover, L6E9 myoblasts overexpressing a dominant-negative mutant of PI 3-kinase p85 regulatory subunit (Δp85) are unable to differentiate. Furthermore, PI 3-kinase is specifically involved in the insulinlike growth factor (IGF)-dependent myogenic pathway. Indeed, the ability of IGF-I, des-1,3-IGF-I, and IGF-II to promote cell fusion and muscle-specific protein expression is impaired after treatment with PI 3-kinase inhibitors or in cells overexpressing Δp85. The identification of additional key downstream elements of the IGF/PI 3-kinase myogenic cascade is crucial to a detailed understanding of the process of muscle differentiation and may generate new tools for skeletal and cardiac muscle regeneration therapies. (Trends Cardiovasc Med 1997;7:198-202). © 1997, Elsevier Science Inc.

  11. Film adhesion in amorphous silicon solar cells

    Indian Academy of Sciences (India)

    A R M Yusoff; M N Syahrul; K Henkel

    2007-08-01

    A major issue encountered during fabrication of triple junction -Si solar cells on polyimide substrates is the adhesion of the solar cell thin films to the substrates. Here, we present our study of film adhesion in amorphous silicon solar cells made on different polyimide substrates (Kapton VN, Upilex-S and Gouldflex), and the effect of tie coats on film adhesion.

  12. Current dental adhesives systems. A narrative review.

    Science.gov (United States)

    Milia, Egle; Cumbo, Enzo; Cardoso, Rielson Jose A; Gallina, Giuseppe

    2012-01-01

    Adhesive dentistry is based on the development of materials which establish an effective bond with the tooth tissues. In this context, adhesive systems have attracted considerable research interest in recent years. Successful adhesive bonding depends on the chemistry of the adhesive, on appropriate clinical handling of the material as well as on the knowledge of the morphological changes caused on dental tissue by different bonding procedures. This paper outlines the status of contemporary adhesive systems, with particular emphasis on chemical characteristics and mode of interaction of the adhesives with enamel and dentinal tissues. Dental adhesives are used for several clinical applications and they can be classified based on the clinical regimen in "etch-and-rinse adhesives" and "self-etch adhesives". Other important considerations concern the different anatomical characteristics of enamel and dentine which are involved in the bonding procedures that have also implications for the technique used as well as for the quality of the bond. Etch-and-rinse adhesive systems generally perform better on enamel than self-etching systems which may be more suitable for bonding to dentine. In order to avoid a possible loss of the restoration, secondary caries or pulp damage due to bacteria penetration or due to cytotoxicity effects of eluted adhesive components, careful consideration of several factors is essential in selecting the suitable bonding procedure and adhesive system for the individual patient situation.

  13. Self-Adjustable Adhesion of Polyampholyte Hydrogels.

    Science.gov (United States)

    Roy, Chanchal Kumar; Guo, Hong Lei; Sun, Tao Lin; Ihsan, Abu Bin; Kurokawa, Takayuki; Takahata, Masakazu; Nonoyama, Takayuki; Nakajima, Tasuku; Gong, Jian Ping

    2015-12-02

    Developing nonspecific, fast, and strong adhesives that can glue hydrogels and biotissues substantially promotes the application of hydrogels as biomaterials. Inspired by the ubiquitous adhesiveness of bacteria, it is reported that neutral polyampholyte hydrogels, through their self-adjustable surface, can show rapid, strong, and reversible adhesion to charged hydrogels and biological tissues through the Coulombic interaction.

  14. 21 CFR 878.4380 - Drape adhesive.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Drape adhesive. 878.4380 Section 878.4380 Food and... GENERAL AND PLASTIC SURGERY DEVICES Surgical Devices § 878.4380 Drape adhesive. (a) Identification. A drape adhesive is a device intended to be placed on the skin to attach a surgical drape....

  15. PCTK3/CDK18 regulates cell migration and adhesion by negatively modulating FAK activity

    Science.gov (United States)

    Matsuda, Shinya; Kawamoto, Kohei; Miyamoto, Kenji; Tsuji, Akihiko; Yuasa, Keizo

    2017-01-01

    PCTAIRE kinase 3 (PCTK3) is a member of the cyclin dependent kinase family, but its physiological function remains unknown. We previously reported that PCTK3-knockdown HEK293T cells showed actin accumulation at the leading edge, suggesting that PCTK3 is involved in the regulation of actin reorganization. In this study, we investigated the physiological function and downstream signal transduction molecules of PCTK3. PCTK3 knockdown in HEK293T cells increased cell motility and RhoA/Rho-associated kinase activity as compared with control cells. We also found that phosphorylation at residue Tyr-397 in focal adhesion kinase (FAK) was increased in PCTK3-knockdown cells. FAK phosphorylation at Tyr-397 was increased in response to fibronectin stimulation, whereas its phosphorylation was suppressed by PCTK3. In addition, excessive expression of PCTK3 led to the formation of filopodia during the early stages of cell adhesion in HeLa cells. These results indicate that PCTK3 controls actin cytoskeleton dynamics by negatively regulating the FAK/Rho signaling pathway. PMID:28361970

  16. Improving the performance of starch-based wood adhesive by using sodium dodecyl sulfate.

    Science.gov (United States)

    Li, Zhaofeng; Wang, Jian; Cheng, Li; Gu, Zhengbiao; Hong, Yan; Kowalczyk, Agnieszka

    2014-01-01

    Sodium dodecyl sulfate (SDS) was used to improve the performance of starch-based wood adhesive. The effects of SDS on shear strength, viscosity and storage stability were investigated. It was shown that, although the addition of 1.5-2% (dry starch basis) SDS resulted in a slight decrease in shear strength, the mobility and storage stability of adhesive were significantly enhanced. Possible mechanisms regarding specific action of SDS were discussed. It was proved, using blue value or differential scanning calorimetry (DSC) analysis, that the amylose-SDS complexes were formed in the adhesive. The complex formation or simple adsorption of SDS with starch molecules might hinder the aggregation of latex particles, as shown by scanning electron microscopy images, and inhibit starch retrogradation, as observed by DSC analysis. As a result, in the presence of SDS, the adhesive had higher mobility and storage stability, indicating that SDS could be used to prepare starch-based wood adhesives with high performance.

  17. Fetotoxic effects of exposure to the vapor of organic solvents from a synthetic adhesive in mice

    Energy Technology Data Exchange (ETDEWEB)

    Tachi, N.; Shimotori, S.; Naruse, N.; Itani, T.; Aoyama, M. (Nagoya City Univ. Medical School (Japan)); Fujise, H.; Sonoki, S. (Azabu Univ., Kanagawa (Japan))

    1994-09-01

    Synthetic adhesives are widely used in various industries as well as at home. Adhesives usually contain several organic solvents which easily vaporize. Exposure can cause aplastic anemia and polyneuropathy in adults. Chronic glue sniffing results in aplastic anemia, polyneuropathy, and muscular atrophy. Inhalation of the solvent contained in adhesives, such as n-hexane, toluene, xylene, and benzene by pregnant animals can decrease the number of live fetuses and retard fetal growth. In humans, the risk of spontaneous abortion is increased in workers exposed to organic solvents. However, information is still limited about the effects of exposure to organic solvents vaporized from adhesives on fetuses. In the present study, female mice were exposed throughout pregnancy to organic solvents vaporized from an adhesive to clarify the effects of the inhalation on progeny. 19 refs., 1 fig., 4 tabs.

  18. A Theoretical Characterization of Curvature Controlled Adhesive Properties of Bio-Inspired Membranes

    DEFF Research Database (Denmark)

    Afferante, Luciano; Heepe, Lars; Casdorff, Kirstin;

    2016-01-01

    Some biological systems, such as the tree frog, Litoria caerulea, and the bush-cricket, Tettigonia viridissima, have developed the ability to control adhesion by changing the curvature of their pads. Active control systems of adhesion inspired by these biological models can be very attractive...... for the development of devices with controllable adhesive properties. In this paper, we present a theory describing the adhesive behavior of an artificial system consisting of an inflatable membrane clamped to a metallic cylinder and filled with air. In such a system, by controlling the internal pressure acting...... on the membrane, it is possible to modulate the adhesive strength. In particular, an increase of the internal pressure and, hence, the curvature of the membrane, results in a decrease of the pull-off force. Results predicted by the theoretical model are in good agreement with experimental data. The model explains...

  19. Application of Organosilane Monolayer Template to Quantitative Evaluation of Cancer Cell Adhesive Ability

    Science.gov (United States)

    Tanii, Takashi; Sasaki, Kosuke; Ichisawa, Kota; Demura, Takanori; Beppu, Yuichi; Vu, Hoan Anh; Thanh Chi, Hoan; Yamamoto, Hideaki; Sato, Yuko

    2011-06-01

    The adhesive ability of two human pancreatic cancer cell lines was evaluated using organosilane monolayer templates (OMTs). Using the OMT, the spreading area of adhered cells can be limited, and this enables us to focus on the initial attachment process of adhesion. Moreover, it becomes possible to arrange the cells in an array and to quantitatively evaluate the number of attached cells. The adhesive ability of the cancer cells cultured on the OMT was controlled by adding (-)-epigallocatechin-3-gallate (EGCG), which blocks a receptor that mediates cell adhesion and is overexpressed in cancer cells. Measurement of the relative ability of the cancer cells to attach to the OMT revealed that the ability for attachment decreased with increasing EGCG concentration. The results agreed well with the western blot analysis, indicating that the OMT can potentially be employed to evaluate the adhesive ability of various cancer cells.

  20. Syndecan-4 proteoglycan regulates the distribution and activity of protein kinase C

    DEFF Research Database (Denmark)

    Oh, E S; Woods, A; Couchman, J R

    1997-01-01

    proteoglycan with heparin-binding moieties. This correlates with protein kinase C (PKC) activation, and PKCalpha can become localized to focal adhesions in normal, but not transformed, cells. PKC activation has been thought to be downstream of initial receptor-ligand interactions. We now show, however......, that syndecan-4 transmembrane heparan sulfate proteoglycan and PKC co-immunoprecipitate and co-patch in vivo. The core protein of syndecan-4 can directly bind the catalytic domain of PKCalpha and potentiate its activation by phospholipid mediators. It can also directly activate PKCalpha in the absence of other...... adhesions. This represents the first report of direct transmembrane signaling through cell surface proteoglycans....

  1. 家蚕吡哆醛激酶基因干扰降低转氨酶基因的转录表达%RNA interference of pyridoxal kinase gene decreases the expression of aminotransferase gene in the silkworm, Bombyx mori

    Institute of Scientific and Technical Information of China (English)

    姚丽丽; 杨欢欢; 张剑韵; 黄龙全

    2015-01-01

    [目的]维生素B6在氨基酸代谢中是多种酶的辅酶,维持氨基酸代谢的正常运行.磷酸吡哆醛(pyridoxal-5'-phosphate,PLP)是维生素B6的主要辅酶形式,吡哆醛激酶(pyridoxal kinase, PLK)是PLP的重要生成酶,本研究试图明确PLK基因与PLP依赖酶之间转录水平的调节关系.[方法]本研究采用RNA干扰(RNA interference,RNAi)方法对家蚕Bombyx mori的PLK基因进行干扰,通过体外合成PLK基因的3个干扰片段(siRNA1,siRNA2和siRNA3),将siRNA从体腔注入5龄第3天的家蚕幼虫体内诱导RNAi.利用荧光定量PCR测定不同干扰片段、不同时间点及不同组织中PLK基因表达量的变化;并测定家蚕体内磷酸丝氨酸转氨酶(phosphoserine aminotransferase,SerB)和天门冬氨酸氨基转移酶(asparate aminotransferase, AST)基因的表达量.[结果]注射干扰片段后48 h干扰效果达到最佳.3个干扰片段干扰效果从高到低依次为siRNA1,siRNA2和siRNA3.RNAi效果最好的是中肠组织,其PLK基因的相对表达量下降了55%.RNA干扰PLK基因后,后部丝腺中SerB和AST基因相对表达量分别下降了90%和29%.[结论]本研究通过RNAi实现了家蚕PLK基因干扰,并进一步证明了家蚕PLK基因和SerB基因及AST基因存在联动调节关系.

  2. Biodegradable beta-Tri-Calciumphosphate/hydroxyethyl methacrylate enhanced three component bone adhesive demonstrates biocompatibility without evidence of systemic toxicity in a rabbit model.

    Science.gov (United States)

    Bauer, Natali B; Brinke, Nina; Heiss, Christian; Skorupa, Agnes B; Peters, Fabian; Kraus, Ralf; Schnettler, Reinhard; Moritz, Andreas

    2009-08-01

    Bone gluing is an attractive surgical technique; however, its use in patients is hampered by a variety of side effects. Therefore, it was the aim of this ethically approved study to evaluate a novel biodegradable beta-Tri-Calciumphosphate (beta-TCP, Cerasorb)-enhanced bone adhesive regarding its toxicity and biocompatibility in a rabbit model. Fifty healthy New Zealand White rabbits were assigned in the study (n = 21) and sham-operated control group (n = 29). In the study group, a cylindrical part (4.6 x 10.0 mm) of the proximal tibia and distal femur was removed, reimplanted, and bone adhesive was applied. Blinded physical examination and sampling for hematology, clinical chemistry, and acute phase proteins (haptoglobin, C-reactive protein (CRP)) was performed before surgery and after 12, 24, 48, 72, 240, and 504 h. Significant findings of the physical examination included a slightly higher grading of warmth (p = 0.0019) and pain (p < 0.0001) of the wound 240 h after surgery in the study group. No significant differences between albumin, haptoglobin, CRP, and urea concentrations in both groups were evident, whereas the study group demonstrated significantly lower leukocyte count, total protein, and globulin concentrations (p < 0.0001). As expected, both groups showed a marked transient increase in muscle enzymes (Creatine Kinase and Aspartate Aminotransferase) following the surgery (p < 0.0001). Twelve to 24 h after surgery, a significant decrease in ionized calcium from 1.38 +/- 0.12 mmol/L to 1.06 +/- 0.13 mmol/L was noted in the study group (p < 0.0001). The results clearly indicated that the novel beta-TCP-enhanced bone adhesive showed good biocompatibility without significant evidence of acute or subacute local or systemic toxicity.

  3. Rho-kinase as a novel therapeutic target in treatment of cardiovascular diseases.

    Science.gov (United States)

    Shimokawa, Hiroaki

    2002-03-01

    Rho-kinase has been identified as one of the effectors of the small GTP-binding protein Rho. Accumulating evidence has demonstrated that the Rho/Rho-kinase-mediated pathway plays an important role in various cellular functions, not only in vascular smooth muscle contraction but also in actin cytoskeleton organization, cell adhesion and motility, cytokinesis, and gene expressions, all of which may be involved in the pathogenesis of arteriosclerosis/atherosclerosis. Indeed, animal experiments have demonstrated that Rho-kinase inhibitors effectively suppress coronary artery spasm and that long-term inhibition of Rho-kinase inhibits the development of coronary arteriosclerotic lesions and even causes regression of coronary vascular lesions in vivo. Recent clinical studies also have demonstrated the inhibitory effect of a Rho-kinase inhibitor on coronary artery spasm in patients with vasospastic angina and on exercise-induced myocardial ischemia in patients with stable effort angina with adequate safety. It is possible that Rho-kinase is also involved in the pathogenesis of other forms of cardiovascular diseases. Thus, Rho-kinase could be regarded as a novel therapeutic target in treatment of cardiovascular diseases.

  4. Photochemical tissue bonding with chitosan adhesive films

    Directory of Open Access Journals (Sweden)

    Piller Sabine C

    2010-09-01

    Full Text Available Abstract Background Photochemical tissue bonding (PTB is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Methods Adhesive films, based on chitosan and containing ~0.1 wt% RB were manufactured and bonded to calf intestine by a solid state laser (λ = 532 nm, Fluence~110 J/cm2, spot size~0.5 cm. A single-column tensiometer, interfaced with a personal computer, tested the bonding strength. K-type thermocouples recorded the temperature (T at the adhesive-tissue interface during laser irradiation. Human fibroblasts were also seeded on the adhesive and cultured for 48 hours to assess cell growth. Results The RB-chitosan adhesive bonded firmly to the intestine with adhesion strength of 15 ± 2 kPa, (n = 31. The adhesion strength dropped to 0.5 ± 0.1 (n = 8 kPa when the laser was not applied to the adhesive. The average temperature of the adhesive increased from 26°C to 32°C during laser exposure. Fibroblasts grew confluent on the adhesive without morphological changes. Conclusion A new biocompatible chitosan adhesive has been developed that bonds photochemically to tissue with minimal temperature increase.

  5. Gecko adhesion pad: a smart surface?

    Science.gov (United States)

    Pesika, Noshir S.; Zeng, Hongbo; Kristiansen, Kai; Zhao, Boxin; Tian, Yu; Autumn, Kellar; Israelachvili, Jacob

    2009-11-01

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  6. Gecko adhesion pad: a smart surface?

    Energy Technology Data Exchange (ETDEWEB)

    Pesika, Noshir S [Chemical and Biomolecular Engineering Department, Tulane University, New Orleans, LA 70118 (United States); Zeng Hongbo [Chemical and Materials Engineering Department, University of Alberta, Edmonton, AB, T6G 2V4 (Canada); Kristiansen, Kai; Israelachvili, Jacob [Chemical Engineering Department, University of California, Santa Barbara, CA 93117 (United States); Zhao, Boxin [Chemical Engineering Department and Waterloo Institute of Nanotechnology, University of Waterloo, Ontario, N2L 3G1 (Canada); Tian Yu [State Key Laboratory of Tribology, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Autumn, Kellar, E-mail: npesika@tulane.ed [Department of Biology, Lewis and Clark College, Portland, OR 97219 (United States)

    2009-11-18

    Recently, it has been shown that humidity can increase the adhesion of the spatula pads that form the outermost (adhesive) surface of the tokay gecko feet by 50% relative to the main adhesion mechanism (i.e. van der Waals adhesive forces), although the mechanism by which the enhancement is realized is still not well understood. A change in the surface hydrophobicity of a gecko setal array is observed when the array, which supports the spatulae, is exposed to a water drop for more than 20 min, suggesting a change in the hydrophilic-lyophilic balance (HLB), and therefore of the conformation of the surface proteins. A surface force apparatus (SFA) was used to quantify these changes, i.e. in the adhesion and friction forces, while shearing the setal array against a silica surface under (i) dry conditions, (ii) 100% humidity and (iii) when fully immersed in water. The adhesion increased in the humid environment but greatly diminished in water. Although the adhesion forces changed significantly, the friction forces remained unaffected, indicating that the friction between these highly textured surfaces is 'load-controlled' rather than 'adhesion-controlled'. These results demonstrate that the gecko adhesive pads have the ability to exploit environmental conditions to maximize their adhesion and stabilize their friction forces. Future designs of synthetic dry adhesives inspired by the gecko can potentially include similar 'smart' surfaces that adapt to their environment.

  7. Nanocapillary Adhesion between Parallel Plates.

    Science.gov (United States)

    Cheng, Shengfeng; Robbins, Mark O

    2016-08-01

    Molecular dynamics simulations are used to study capillary adhesion from a nanometer scale liquid bridge between two parallel flat solid surfaces. The capillary force, Fcap, and the meniscus shape of the bridge are computed as the separation between the solid surfaces, h, is varied. Macroscopic theory predicts the meniscus shape and the contribution of liquid/vapor interfacial tension to Fcap quite accurately for separations as small as two or three molecular diameters (1-2 nm). However, the total capillary force differs in sign and magnitude from macroscopic theory for h ≲ 5 nm (8-10 diameters) because of molecular layering that is not included in macroscopic theory. For these small separations, the pressure tensor in the fluid becomes anisotropic. The components in the plane of the surface vary smoothly and are consistent with theory based on the macroscopic surface tension. Capillary adhesion is affected by only the perpendicular component, which has strong oscillations as the molecular layering changes.

  8. Compomers: adhesion and setting reactions.

    Science.gov (United States)

    Moodley, Desi; Grobler, Sias R

    2003-02-01

    The term compomer is misleading as it suggests a combination of glass-ionomer and composite technology. This has led to confusion as to its clinical uses as well as the way it bonds to tooth structure. However, the properties and adhesion of compomers to tooth structure suggest a closer link to composites than to glass-ionomers. The clinical significance of this is that compomers lack direct chemical adhesion to any tooth structure and therefore needs to be bonded to tooth structure similar to composites via a separate bonding agent. Their closeness to composites however, does not make them composite substitutes or replacements. Dentists should strictly follow instructions by the manufacturers because failure of materials can mostly be blamed on the clinician rather than on the material.

  9. Effects of tensile and compressive in-plane stress fields on adhesion in laser induced delamination experiments

    NARCIS (Netherlands)

    Fedorov, A.; Vellinga, W. P.; De Hosson, J. Th. M.

    2008-01-01

    In this work, the adhesion of a polymer coating on steel substrate subjected to uniaxial tensile plastic deformations was studied with the laser induced delamination technique. A decrease in the practical work of adhesion has been measured as the deformation of the substrate progressed. Moreover, it

  10. Bacterial adhesion and biofilms on surfaces

    Institute of Scientific and Technical Information of China (English)

    Trevor Roger Garrett; Manmohan Bhakoo; Zhibing Zhang

    2008-01-01

    Bacterial adhesion has become a significant problem in industry and in the domicile,and much research has been done for deeper understanding of the processes involved.A generic biological model of bacterial adhesion and population growth called the bacterial biofilm growth cycle,has been described and modified many times.The biofilm growth cycle encompasses bacterial adhesion at all levels,starting with the initial physical attraction of bacteria to a substrate,and ending with the eventual liberation of cell dusters from the biofilm matrix.When describing bacterial adhesion one is simply describing one or more stages of biofilm development,neglecting the fact that the population may not reach maturity.This article provides an overview of bacterial adhesion.cites examples of how bac-terial adhesion affects industry and summarises methods and instrumentation used to improve our understanding of the adhesive prop-erties of bacteria.

  11. Raman microspectroscopic study of biomolecular structure inside living adhesive cells

    Institute of Scientific and Technical Information of China (English)

    李光; 杨红英; 许以明; 张志义

    2002-01-01

    Cells adhesion is very important for many physiological processes. Using advanced Raman microspectroscopic technique, we selected T Leukemia cells (Jurkat) as the materials and obtained simultaneously conformation information of various biomolecules inside the whole living cells. By comparing the Raman microspectroscopic spectra of single and adhesive cancer cells, we found for the first time that when cells adhered, the conformation of the biomolecules (DNA, protein, carbohydrates and lipids) inside the cells had different changes: (i) the backbone of double-stranded DNA maintained orderly B-form or modified B-form conformation, whereas the groups of its deoxyribose and bases were modified; (ii) the conformational changes of the main chain and the side chain in the protein were obviously variant. The lines intensity belonging to α-helix andβ-sheet decreased, while that ofβ-turn increased. Tyrosine and tryptophane residues of the protein changed from "buried state" to "exposed state"; the lines intensity of its sulfhydryl group also increased; the conformation of its disulfide bond changed from two kinds to three kinds. These facts suggest that the cells adhesion causes changes in H-bonds organization of the main chain and environment of the side chain in the protein; (iii) the groups of the carbohydrates were also modified simultaneously; (iv) the conformation of the lipids bilayers of the membranes changed obviously; the order parameter for lateral interaction between chains decreased gradually with the increase of number of the adhesive cells. So cells adhesion resulted in an increase in fluidity of the membrane and ion permeability on the membrane.

  12. Effect of antibacterial dental adhesive on multispecies biofilms formation.

    Science.gov (United States)

    Zhang, K; Wang, S; Zhou, X; Xu, H H K; Weir, M D; Ge, Y; Li, M; Wang, S; Li, Y; Xu, X; Zheng, L; Cheng, L

    2015-04-01

    Antibacterial adhesives have favorable prospects to inhibit biofilms and secondary caries. The objectives of this study were to investigate the antibacterial effect of dental adhesives containing dimethylaminododecyl methacrylate (DMADDM) on different bacteria in controlled multispecies biofilms and its regulating effect on development of biofilm for the first time. Antibacterial material was synthesized, and Streptococcus mutans, Streptococcus gordonii, and Streptococcus sanguinis were chosen to form multispecies biofilms. Lactic acid assay and pH measurement were conducted to study the acid production of controlled multispecies biofilms. Anthrone method and exopolysaccharide (EPS):bacteria volume ratio measured by confocal laser scanning microscopy were performed to determine the EPS production of biofilms. The colony-forming unit counts, scanning electron microscope imaging, and dead:live volume ratio decided by confocal laser scanning microscopy were used to study the biomass change of controlled multispecies biofilms. The TaqMan real-time polymerase chain reaction and fluorescent in situ hybridization imaging were used to study the proportion change in multispecies biofilms of different groups. The results showed that DMADDM-containing adhesive groups slowed the pH drop and decreased the lactic acid production noticeably, especially lactic acid production in the 5% DMADDM group, which decreased 10- to 30-fold compared with control group (P biofilms compared with control group (P biofilm had a more healthy development tendency after the regulation of DMADDM. In conclusion, the adhesives containing DMADDM had remarkable antimicrobial properties to serve as "bioactive" adhesive materials and revealed its potential value for antibiofilm and anticaries clinical applications.

  13. Syndecans, signaling, and cell adhesion

    DEFF Research Database (Denmark)

    Couchman, J R; Woods, A

    1996-01-01

    Syndecans are transmembrane proteoglycans which can participate in diverse cell surface interactions, involving extracellular matrix macromolecules, growth factors, protease inhibitors, and even viral entry. Currently, all extracellular interactions are believed to be mediated by distinct...... structures within the heparan sulfate chains, leaving the roles of chondroitin sulfate chains and extracellular portion of the core proteins to be elucidated. Evidence that syndecans are a class of receptor involved in cell adhesion is mounting, and their small cytoplasmic domains may link...

  14. Underwater adhesion: The barnacle way

    Digital Repository Service at National Institute of Oceanography (India)

    Khandeparker, L.; Anil, A.C.

    the cement proteins of M. rosa were separated using reversed-phase High Performance Liquid Chromatography (HPLC) and previously unidentified protein named 20 kDa M. rosa cement protein (Mrcp-20k) was found [67]. Its primary structure was revealed by cloning... to be an effective method of combating fouling. Barnacle adhesion strength was used to screen seventy-seven polydimethylsiloxane elastomeric coatings for fouling-release properties. Optimum fouling- release performance was dependent on the interaction of fluid type...

  15. Shelf Stable Epoxy Repair Adhesive

    Science.gov (United States)

    2015-02-01

    manufacturing operations are more efficient , discarding less expired film. Commercial and military aircraft repair operations at Boeing experience very similar...successfully encapsulated at concentrations greater than 50 wt% within four N N = CC Infoscitex Corporation Shelf Stable Epoxy Resin Adhesive WP-1763 8...affects the composition of the encapsulant , which in turn affects the ability of the encapsulant to wet the core phase, the barrier properties of the

  16. Thrombin generation in abdominal sepsis is Rho-kinase-dependent.

    Science.gov (United States)

    Wang, Yongzhi; Braun, Oscar Ö; Zhang, Su; Norström, Eva; Thorlacius, Henrik

    2015-05-08

    Sepsis causes severe derangements of the coagulation system. However, the signaling mechanisms regulating sepsis-induced thrombin generation remain elusive. Herein, we hypothesized that Rho-kinase might be an important regulator of thrombin generation in abdominal sepsis. Abdominal sepsis was induced by cecal ligation and puncture (CLP) in C57Bl/6 mice. Thrombin generation, coagulation factors, lung histology and myeloperoxidase (MPO) activity were determined 6 h and 24 h after induction of CLP. Induction of CLP triggered a systemic inflammatory response characterized by neutrophil accumulation and tissue injury in the lung as well as thrombocytopenia and leukocytopenia. Administration of Y-27632, a Rho-kinase inhibitor, attenuated these markers of systemic inflammation in CLP animals. Moreover, peak thrombin formation was decreased by 77% and 81% in plasma from mice 6 h and 24 h after induction of CLP. Total thrombin generation was reduced by 64% and 67% 6 h and 24 h after CLP induction, respectively. Notably, administration of Y-27632 increased peak formation by 99% and total thrombin generation by 66% in plasma from septic animals. In addition, CLP markedly decreased plasma levels of prothrombin, factor V and factor X at 6 h and 24 h. Interestingly, Rho-kinase inhibition significantly enhanced levels of prothrombin, factor V and factor X in plasma from septic mice. In addition, inhibition of Rho-kinase decreased CLP-induced elevations of CXCL2 by 36% and interleukin-6 by 38%. These novel findings suggest that sepsis-induced thrombin generation is regulated by Rho-kinase. Moreover, inhibition of Rho-kinase reverses sepsis-evoked consumption of coagulation factors. Thus, our results show that targeting Rho-kinase signaling might protect against coagulation dysfunction in abdominal sepsis.

  17. Impact of pericardial adhesions on diastolic function as assessed by vortex formation time, a parameter of transmitral flow efficiency

    Directory of Open Access Journals (Sweden)

    Heys Jeffrey J

    2010-09-01

    Full Text Available Abstract Background Pericardial adhesions are a pathophysiological marker of constrictive pericarditis (CP, which impairs cardiac filling by limiting the total cardiac volume compliance and diastolic filling function. We studied diastolic transmitral flow efficiency as a new parameter of filling function in a pericardial adhesion animal model. We hypothesized that vortex formation time (VFT, an index of optimal efficient diastolic transmitral flow, is altered by patchy pericardial-epicardial adhesions. Methods In 8 open-chest pigs, the heart was exposed while preserving the pericardium. We experimentally simulated early pericardial constriction and patchy adhesions by instilling instant glue into the pericardial space and using pericardial-epicardial stitches. We studied left ventricular (LV function and characterized intraventricular blood flow with conventional and Doppler echocardiography at baseline and following the experimental intervention. Results Significant decreases in end-diastolic volume, ejection fraction, stroke volume, and late diastolic filling velocity reflected the effects of the pericardial adhesions. The mean VFT value decreased from 3.61 ± 0.47 to 2.26 ± 0.45 (P = 0.0002. Hemodynamic variables indicated the inhibiting effect of pericardial adhesion on both contraction (decrease in systolic blood pressure and +dP/dt decreased and relaxation (decrease in the magnitude of -dP/dt and prolongation of Tau function. Conclusion Patchy pericardial adhesions not only negatively impact LV mechanical functioning but the decrease of VFT from normal to suboptimal value suggests impairment of transmitral flow efficiency.

  18. Activation of sonic hedgehog signaling enhances cell migration and invasion by induction of matrix metalloproteinase-2 and -9 via the phosphoinositide-3 kinase/AKT signaling pathway in glioblastoma.

    Science.gov (United States)

    Chang, Liang; Zhao, Dan; Liu, Hui-Bin; Wang, Qiu-Shi; Zhang, Ping; Li, Chen-Long; Du, Wen-Zhong; Wang, Hong-Jun; Liu, Xing; Zhang, Zhi-Ren; Jiang, Chuan-Lu

    2015-11-01

    Aberrant hedgehog signaling contributes to the development of various malignancies, including glioblastoma (GBM). However, the potential mechanism of hedgehog signaling in GBM migration and invasion has remained to be elucidated. The present study showed that enhanced hedgehog signaling by recombinant human sonic hedgehog N‑terminal peptide (rhSHH) promoted the adhesion, invasion and migration of GBM cells, accompanied by increases in mRNA and protein levels of matrix metalloproteinase‑2 (MMP‑2) and MMP‑9. However, inhibition of hedgehog signaling with cyclopamine suppressed the adhesion, invasion and migration of GBM cells, accompanied by decreases in mRNA and protein levels of MMP‑2 and ‑9. Furthermore, it was found that MMP‑2- and MMP‑9-neutralizing antibodies or GAM6001 reversed the inductive effects of rhSHH on cell migration and invasion. In addition, enhanced hedgehog signaling by rhSHH increased AKT phosphorylation, whereas blockade of hedgehog signaling decreased AKT phosphorylations. Further experiments showed that LY294002, an inhibitor of phosphoinositide-3 kinase (PI3K), decreased rhSHH‑induced upregulation of MMP‑2 and ‑9. Finally, the protein expression of glioblastoma-associated oncogene 1 was positively correlated with levels of phosphorylated AKT as well as protein expressions of MMP‑2 and ‑9 in GBM tissue samples. In conclusion, the present study indicated that the hedgehog pathway regulates GBM-cell migration and invasion by increasing MMP-2 and MMP-9 production via the PI3K/AKT pathway.

  19. Modeling of Sylgard Adhesive Strength

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, Ralph Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-02-03

    Sylgard is the name of a silicone elastomeric potting material manufactured by Dow Corning Corporation.1 Although the manufacturer cites its low adhesive strength as a feature of this product, thin layers of Sylgard do in fact have a non-negligible strength, which has been measured in recent tensile and shear debonding tests. The adhesive strength of thin layers of Sylgard potting material can be important in applications in which components having signi cantly di erent thermal expansion properties are potted together, and the potted assembly is subjected to temperature changes. The tensile and shear tractions developed on the potted surfaces of the components can cause signi cant internal stresses, particularly for components made of low-strength materials with a high area-to-volume ratio. This report is organized as follows: recent Sylgard debonding tests are rst brie y summarized, with particular attention to the adhesion between Sylgard and PBX 9501, and also between Sylgard and aluminum. Next, the type of numerical model that will be used to simulate the debonding behavior exhibited in these tests is described. Then the calibration of the debonding model will be illustrated. Finally, the method by which the model parameters are adjusted (scaled) to be applicable to other, non- tested bond thicknesses is summarized, and all parameters of the model (scaled and unscaled) are presented so that other investigators can reproduce all of the simulations described in this report as well as simulations of the application of interest.

  20. A review of our development of dental adhesives--effects of radical polymerization initiators and adhesive monomers on adhesion.

    Science.gov (United States)

    Ikemura, Kunio; Endo, Takeshi

    2010-03-01

    This paper reviews the development of dental adhesives by collating information of related studies from original scientific papers, reviews, and patent literatures. Through our development, novel radical polymerization initiators, adhesive monomers, and microcapsules were synthesized, and their effects on adhesion were investigated. It was found that 5-monosubstituted barbituric acid (5-MSBA)-containing ternary initiators in conjunction with adhesive monomers contributed to effective adhesion with good polymerization reactivity. Several kinds of novel adhesive monomers bearing carboxyl group, phosphonic acid group or sulfur-containing group were synthesized, and investigated their multi-purpose bonding functions. It was suggested that the flexible methylene chain in the structure of adhesive monomers played a pivotal role in their enhanced bonding durability. It was found that the combination of acidic monomers with sulfur-containing monomer markedly improved adhesion to enamel, dentin, porcelain, alumina, zirconia, non-precious metals and precious metals. A new poly(methyl methacrylate) (PMMA)-type adhesive resin comprising microencapsulated polymerization initiators was also found to exhibit both good formulation stability and excellent adhesive property.

  1. Adhesion of food-borne bacteria to stainless steel is reduced by food conditioning films

    DEFF Research Database (Denmark)

    Bernbom, Nete; Ng, Yin; Jorgensen, R.L.

    2009-01-01

    Preconditioning of stainless steel with aqueous cod muscle extract significantly impedes subsequent bacterial adhesion most likely due to repelling effects of fish tropomyosin. The purpose of this study was to determine if other food conditioning films decrease or enhance bacterial adhesion...... to stainless steel. Attachment of Pseudomonas fluorescens AH2 to stainless steel coated with water-soluble coatings of animal origin was significantly reduced as compared with noncoated stainless steel or stainless steel coated with laboratory substrate or extracts of plant origin. Coating with animal extracts...... also decreases adhesion of other food-relevant bacteria. The manipulation of adhesion was not attributable to growth inhibitory effects. Chemical analysis revealed that the stainless steels were covered by homogenous layers of adsorbed proteins. The presence of tropomyocin was indicated by appearance...

  2. The role of Na-hylan in reducing postsurgical tendon adhesions: Part 2.

    Science.gov (United States)

    Weiss, C; Suros, J M; Michalow, A; Denlinger, J; Moore, M; Tejeiro, W

    1987-01-01

    Na-hylan, a chemically modified sodium hyaluronate jelly, was studied mechanically and histologically as a surgical device to diminish tendon adhesions in rabbit extensor hallucis longus tendons after severe surgical trauma. Na-hylan jelly of high viscoelastic properties was found to be highly effective in decreasing tendon adhesions. Na-hylan jelly of low viscoelastic properties was not effective in diminishing adhesion formation. There was no interference with the tensile strength of tendon healing, and no evidence of acute or chronic inflammatory response to the Na-hylan jelly.

  3. Dynamic interplay between adhesion surfaces in carcinomas:Cell-cell and cell-matrix crosstalk

    Institute of Scientific and Technical Information of China (English)

    Yvonne E Smith; Sri HariKrishna Vellanki; Ann M Hopkins

    2016-01-01

    Cell-cell and cell-matrix signaling and communication between adhesion sites involve mechanisms which are required for cellular functions during normal development and homeostasis; however these cellular functions and mechanisms are often deregulated in cancer. Aberrant signaling at cell-cell and cell-matrix adhesion sites often involves downstream mediators including Rho GTPases and tyrosine kinases. This review discusses these molecules as putative mediators of cellular crosstalk between cell-cell and cell-matrix adhesion sites, in addition to their attractiveness as therapeutic targets in cancer. Interestingly, inter-junctional crosstalk mechanisms are frequently typified by the way in which bacterial and viral pathogens opportunistically infect or intoxicate mammalian cells. This review therefore also discusses the concept of learning from pathogen-host interaction studies to better understand coordinated communication between cell-cell and cell-matrix adhesion sites, in addition to highlighting the potential therapeutic usefulness of exploiting pathogens or their products to tap into inter-junctional crosstalk. Taken together, we feel that increased knowledge around mechanisms of cell-cell and cell-matrix adhesion site crosstalk and consequently a greater understanding of their therapeutic targeting offers a unique opportunity to contribute to the emerging molecular revolution in cancer biology.

  4. Matrine inhibits the expression of adhesion molecules in activated vascular smooth muscle cells.

    Science.gov (United States)

    Liu, Jun; Zhang, Lihua; Ren, Yingang; Gao, Yanli; Kang, Li; Lu, Shaoping

    2016-03-01

    Atherosclerosis is a chronic inflammatory disease associated with increased expression of adhesion molecules in vascular smooth muscle cells (VSMCs). Matrine is a main active ingredient of Sophora flavescens roots, which are used to treat inflammatory diseases. However, the effects of matrine on the expression of adhesion molecules in VSMCs have largely remained elusive. Therefore, the present study investigated the effects of matrine on the expression of adhesion molecules in tumor necrosis factor (TNF)‑α‑stimulated human aortic smooth muscle cells (HASMCs). The results showed that matrine inhibited the expression of vascular cell adhesion molecule‑1 (VCAM‑1) and intercellular adhesion molecule‑1 (ICAM‑1) in TNF‑α‑stimulated HASMCs. Matrine markedly inhibited the TNF‑α‑induced expression of nuclear factor (NF)‑κB p65 and prevented the TNF‑α‑caused degradation of inhibitor of NF‑κB; it also inhibited TNF‑α‑induced activation of mitogen‑activated protein kinases (MAPKs). Furthermore, matrine inhibited the production of intracellular reactive oxygen species (ROS) in TNF‑α‑stimulated HASMCs. In conclusion, the results of the present study demonstrated that matrine inhibited the expression of VCAM‑1 and ICAM‑1 in TNF‑α‑stimulated HASMCs via the suppression of ROS production as well as NF‑κB and MAPK pathway activation. Therefore, matrine may have a potential therapeutic use for preventing the advancement of atherosclerotic lesions.

  5. Roles of paxillin family members in adhesion and ECM degradation coupling at invadosomes

    Science.gov (United States)

    Petropoulos, Christos; Oddou, Christiane; Emadali, Anouk; Hiriart-Bryant, Edwige; Boyault, Cyril; Faurobert, Eva; Vande Pol, Scott; Kim-Kaneyama, Joo-ri; Kraut, Alexandra; Coute, Yohann; Block, Marc; Albiges-Rizo, Corinne

    2016-01-01

    Invadosomes are acto-adhesive structures able to both bind the extracellular matrix (ECM) and digest it. Paxillin family members—paxillin, Hic-5, and leupaxin—are implicated in mechanosensing and turnover of adhesion sites, but the contribution of each paxillin family protein to invadosome activities is unclear. We use genetic approaches to show that paxillin and Hic-5 have both redundant and distinctive functions in invadosome formation. The essential function of paxillin-like activity is based on the coordinated activity of LD motifs and LIM domains, which support invadosome assembly and morphology, respectively. However, paxillin preferentially regulates invadosome assembly, whereas Hic-5 regulates the coupling between ECM degradation and acto-adhesive functions. Mass spectrometry analysis revealed new partners that are important for paxillin and Hic-5 specificities: paxillin regulates the acto-adhesive machinery through janus kinase 1 (JAK1), whereas Hic-5 controls ECM degradation via IQGAP1. Integrating the redundancy and specificities of paxillin and Hic-5 in a functional complex provides insights into the coupling between the acto-adhesive and ECM-degradative machineries in invadosomes. PMID:27269065

  6. Genistein inhibits human TNF-α-induced porcine endothelial cell adhesiveness for human monocytes and natural killer cells

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Cellular immune response is a major barrier to xenotransplantation. Human tumor necrosis factor-α (hTNF-α) possesses cross-species activity and directly amplifies the immune rejection via the upregulation of adhesion molecules on porcine endothelium. We investigated the role of protein tyrosine phosphorylation in the induction of expression of E-sclectin and vascular cell adhesion molecule-1 (VCAM-1), and the augmentation of adhesion of human peripheral blood monocytes (PBMo) and natural killer cells (PBNK), after rhTNF-α-stimulation of porcine aortic endothelial cells (PAEC) in vitro, rhTNF-α-increased adhesiveness of PAEC for both PBMo and PBNK was dose-dependently reduced by pretreatment of PAEC with the selective protein tyrosine kinase (PTK) inhibitor genistein. The inhibitory effect occurred at the early time of PAEC activation triggered by rhTNF-α, and was completely reversible. PTK activity assay indicated that genistein also suppressed rhTNF-α stimulated activation of protein tyrosine kinases (PTKs) in PAEC in a dose-dependent manner. Flow cytometric analysis showed that genistein inhibited the upregulation of E-selectin and VCAM-1 by rhTNF-α. These results suggest that PTKs may regulate the expression of E-selectin and VCAM-1 on PAEC and the adherence of PBMo and PBNK induced by rhTNF-α. Moreover, dietary genistein, used as an adhesion antagonist, may contribute to managing the cell-mediated rejection in the clinical application.

  7. Diacylglycerol Kinase Inhibition and Vascular Function.

    Science.gov (United States)

    Choi, Hyehun; Allahdadi, Kyan J; Tostes, Rita C A; Webb, R Clinton

    2009-01-01

    Diacylglycerol kinases (DGKs), a family of lipid kinases, convert diacylglycerol (DG) to phosphatidic acid (PA). Acting as a second messenger, DG activates protein kinase C (PKC). PA, a signaling lipid, regulates diverse functions involved in physiological responses. Since DGK modulates two lipid second messengers, DG and PA, regulation of DGK could induce related cellular responses. Currently, there are 10 mammalian isoforms of DGK that are categorized into five groups based on their structural features. These diverse isoforms of DGK are considered to activate distinct cellular functions according to extracellular stimuli. Each DGK isoform is thought to play various roles inside the cell, depending on its subcellular localization (nuclear, ER, Golgi complex or cytoplasm). In vascular smooth muscle, vasoconstrictors such as angiotensin II, endothelin-1 and norepinephrine stimulate contraction by increasing inositol trisphosphate (IP(3)), calcium, DG and PKC activity. Inhibition of DGK could increase DG availability and decrease PA levels, as well as alter intracellular responses, including calcium-mediated and PKC-mediated vascular contraction. The purpose of this review is to demonstrate a role of DGK in vascular function. Selective inhibition of DGK isoforms may represent a novel therapeutic approach in vascular dysfunction.

  8. A measurement system analysis with design of experiments: Investigation of the adhesion performance of a pressure sensitive adhesive with the probe tack test.

    Science.gov (United States)

    Michaelis, Marc; Leopold, Claudia S

    2015-12-30

    The tack of a pressure sensitive adhesive (PSA) is not an inherent material property and strongly depends on the measurement conditions. Following the concept of a measurement system analysis (MSA), influencing factors of the probe tack test were investigated by a design of experiments (DoE) approach. A response surface design with 38 runs was built to evaluate the influence of detachment speed, dwell time, contact force, adhesive film thickness and API content on tack, determined as the maximum of the stress strain curve (σmax). It could be shown that all investigated factors have a significant effect on the response and that the DoE approach allowed to detect two-factorial interactions between the dwell time, the contact force, the adhesive film thickness and the API content. Surprisingly, it was found that tack increases with decreasing and not with increasing adhesive film thickness.

  9. Chinese medicine compound Changtong oral liquid on postoperative intestinal adhesions

    Institute of Scientific and Technical Information of China (English)

    Xi-Xiao Yang; Han-Ping Shi; Lian-Bing Hou

    2005-01-01

    AIM: The aim of this study was to observe the effect of a Chinese medicine compound Changtong oral liquid (CT) on tissue plasminogen activity (t-PA), plasminogen activator inhibitor (PAI), TGF-β1 and hydroxyproline (OHP).METHODS: Two sets of animal experiments were performed in the present study. Forty New Zealand rabbits and 48 Sprague-Dawley (SD) rats were assigned randomly to one of the five groups: sham adhesion, adhesion with saline, adhesion with low dosage of the CT, adhesion with middle dosage of the CT and adhesion with high dosage of the CT. t-PA and PAI activity in plasma, OHP and TGF-β1 expression in adhesion were investigated. Analysis of variance was used to test differences among groups.RESULTS: CT treatment increased plasma t-PA activity in rabbits but decreased TGF-β1 activity in rats. The data were expressed from low to high dose respectively as follows: t-PA, 46.1±8.6 μkat/L, 59.6±10.1 μkat/L, 64.0±11.5 μkat/L; TGF-β1 28±7.23%, 31±3.05%, 30±4.04%. There were significant differences compared with saline-treated animals (t-PA 26.4±5.1 μkat/L, TGF-β1 54±5.51%). OHP content in cecum of rabbits from middle and high but not low dose of CT lowered significantly as compared with saline-treated rabbits, 0.3641±0.1373, 0.3348±0.0321, 0.2757±0.0497 mg/g vs0.4183±0.0883 mg/g of protein, P>0.05, P<0.05, P<0.05 respectively. The rabbit plasma PAI activity and OHP content in abdominal wall had no difference in all groups.CONCLUSION: CT treatment significantly enhanced t-PA activity in rabbits, but decreased TGF-β1 content in rats, OHP content in cecum of rabbits, and failed to affect the activity of PAI and OHP content in abdominal wall in rabbits,compared with saline group. The result suggests that CT could effectively prevent adhesions without interfering wound healing.

  10. Adhesion measurement of a buried Cr interlayer on polyimide

    Science.gov (United States)

    Marx, Vera M.; Kirchlechner, Christoph; Zizak, Ivo; Cordill, Megan J.; Dehm, Gerhard

    2015-06-01

    A fundamental knowledge and understanding of the adhesion behaviour of metal-polymer systems is important as interface failure leads to a complete breakdown of flexible devices. A combination of in situ atomic force microscopy for studying topological changes and in situ synchrotron based stress measurements both during film tensile testing were used to estimate the adhesion energy of a thin bilayer film. The film systems consisted of 50-200 nm Cu with a 10 nm Cr adhesion layer on 50 μm thick polyimide. If the Cu film thickness is decreased to 50 nm the Cr interlayer starts dominating the system behaviour. An apparent transition from plastic to predominantly brittle deformation behaviour of the Cu can be observed. Then, compressive stresses in the transverse direction are high enough to cause delamination and buckling of the Cr interlayer from the substrate. This opens a new route to induce buckling of a brittle interlayer between a ductile film and a compliant substrate which is used to determine the interfacial adhesion energy.

  11. Effect of Superhydrophobic Surface of Titanium on Staphylococcus aureus Adhesion

    Directory of Open Access Journals (Sweden)

    Peifu Tang

    2011-01-01

    Full Text Available Despite the systemic antibiotics prophylaxis, orthopedic implants still remain highly susceptible to bacterial adhesion and resulting in device-associated infection. Surface modification is an effective way to decrease bacterial adhesion. In this study, we prepared surfaces with different wettability on titanium surface based on TiO2 nanotube to examine the effect of bacterial adhesion. Firstly, titanium plates were calcined to form hydrophilic TiO2 nanotube films of anatase phase. Subsequently, the nanotube films and inoxidized titaniums were treated with 1H, 1H, 2H, 2H-perfluorooctyl-triethoxysilane (PTES, forming superhydrophobic and hydrophobic surfaces. Observed by SEM and contact angle measurements, the different surfaces have different characteristics. Staphylococcus aureus (SA adhesion on different surfaces was evaluated. Our experiment results show that the superhydrophobic surface has contact angles of water greater than 150∘ and also shows high resistance to bacterial contamination. It is indicated that superhydrophobic surface may be a factor to reduce device-associated infection and could be used in clinical practice.

  12. Study of the Mechanism of Essential Garlic Oil Inhibiting Interleukin-1α-Induced Monocyte Adhesion to Endothelial Cells

    Institute of Scientific and Technical Information of China (English)

    葛璐璐; 张薇; 戴云; 臧燕; 黄纯洁

    2001-01-01

    To observe the effects of essential garlic oil (EGO) on vascular cell adhesive molecule-1 (VCAM-1) expression of endothelial cells and monocyte-endothelial cell adhesion rate induced by interleukin-1α (IL-1α). Methods: Human umbilical vein endothelial cells (HUVEC) were isolated by trypsin digestion method and co-cultured with IL-1α or EGO+IL-1α in the absence or presence of U937 monocyte. Monocyte-endothelial cell adhesion rate was examined with reverted microscope. VCAM-1 expression of endothelial cells was measured by ACAS 570 confocal microscope, and the data were presented as mean fluorescent intensity. Results: EGO significantly inhibited IL-1α-induced endothelial expression of VCAM-1, and thus markedly decreased monocyte-endothelial cell adhesion rate. Conclusion: EGO has the effect on antagonizing adhesion of monocyte and vascular endothelial cell, which might be due to its inhibition on adhesive molecular expression on the surface of endothelial cells.

  13. ERK kinases modulate the activation of PI3 kinase related kinases (PIKKs) in DNA damage response.

    Science.gov (United States)

    Lin, Xiaozeng; Yan, Judy; Tang, Damu

    2013-12-01

    DNA damage response (DDR) is the critical surveillance mechanism in maintaining genome integrity. The mechanism activates checkpoints to prevent cell cycle progression in the presence of DNA lesions, and mediates lesion repair. DDR is coordinated by three apical PI3 kinase related kinases (PIKKs), including ataxia-telangiectasia mutated (ATM), ATM- and Rad3-related (ATR), and DNA-PKcs (the catalytic subunit of the DNA dependent protein kinase). These kinases are activated in response to specific DNA damage or lesions, resulting in checkpoint activation and DNA lesion repair. While it is clear that the pathways of ATM, ATR, and DNA-PK are the core components of DDR, there is accumulating evidence revealing the involvement of other cellular pathways in regulating DDR; this is in line with the concept that in addition to being a nuclear event DDR is also a cellular process. One of these pathways is the extracellular signal-regulated kinase (ERK) MAPK (mitogen-activated protein kinase) pathway. ERK is a converging point of multiple signal transduction pathways involved in cell proliferation, differentiation, and apoptosis. Adding to this list of pathways is the recent development of ERK in DDR. The ERK kinases (ERK1 and ERK2) contribute to the proper execution of DDR in terms of checkpoint activation and the repair of DNA lesions. This review summarizes the contributions of ERK to DDR with emphasis on the relationship of ERK kinases with the activation of ATM, ATR, and DNA-PKcs.

  14. Compromized geranylgeranylation of RhoA and Rac1 in mevalonate kinase deficiency

    NARCIS (Netherlands)

    Henneman, L.; Schneiders, M.S.; Turkenburg, M.; Waterham, H.R.

    2010-01-01

    Mevalonate kinase deficiency (MKD) is an autoinflammatory disorder caused by mutations in the MVK gene resulting in decreased activity of the enzyme mevalonate kinase (MK). Although MK is required for biosynthesis of all isoprenoids, in MKD, in particular, the timely synthesis of geranylgeranyl pyro

  15. Molecular Imaging of the ATM Kinase Activity

    Energy Technology Data Exchange (ETDEWEB)

    Williams, Terence M. [Department of Radiation Oncology, Ohio State University, Columbus, Ohio (United States); Nyati, Shyam [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Center for Molecular Imaging, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Ross, Brian D. [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Rehemtulla, Alnawaz, E-mail: alnawaz@umich.edu [Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Center for Molecular Imaging, University of Michigan Medical Center, Ann Arbor, Michigan (United States); Department of Radiology, University of Michigan Medical Center, Ann Arbor, Michigan (United States)

    2013-08-01

    Purpose: Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA-damage response, including from DNA double-strand breaks. ATM activation results in the initiation of a complex cascade of events including DNA damage repair, cell cycle checkpoint control, and survival. We sought to create a bioluminescent reporter that dynamically and noninvasively measures ATM kinase activity in living cells and subjects. Methods and Materials: Using the split luciferase technology, we constructed a hybrid cDNA, ATM-reporter (ATMR), coding for a protein that quantitatively reports on changes in ATM kinase activity through changes in bioluminescence. Results: Treatment of ATMR-expressing cells with ATM inhibitors resulted in a dose-dependent increase in bioluminescence activity. In contrast, induction of ATM kinase activity upon irradiation resulted in a decrease in reporter activity that correlated with ATM and Chk2 activation by immunoblotting in a time-dependent fashion. Nuclear targeting improved ATMR sensitivity to both ATM inhibitors and radiation, whereas a mutant ATMR (lacking the target phosphorylation site) displayed a muted response. Treatment with ATM inhibitors and small interfering (si)RNA-targeted knockdown of ATM confirm the specificity of the reporter. Using reporter expressing xenografted tumors demonstrated the ability of ATMR to report in ATM activity in mouse models that correlated in a time-dependent fashion with changes in Chk2 activity. Conclusions: We describe the development and validation of a novel, specific, noninvasive bioluminescent reporter that enables monitoring of ATM activity in real time, in vitro and in vivo. Potential applications of this reporter include the identification and development of novel ATM inhibitors or ATM-interacting partners through high-throughput screens and in vivo pharmacokinetic/pharmacodynamic studies of ATM inhibitors in preclinical models.

  16. Chitosan Adhesive Films for Photochemical Tissue Bonding

    Science.gov (United States)

    Lauto, Antonio; Mawad, Damia; Barton, Matthew; Piller, Sabine C.; Longo, Leonardo

    2011-08-01

    Photochemical tissue bonding (PTB) is a promising sutureless technique for tissue repair. PTB is often achieved by applying a solution of rose bengal (RB) between two tissue edges, which are irradiated by a green laser to crosslink collagen fibers with minimal heat production. In this study, RB has been incorporated in chitosan films to create a novel tissue adhesive that is laser-activated. Materials and Methods. Adhesive films, based on chitosan and containing ˜0.1wt% RB were manufactured and bonded to calf intestine by a solid state laser (wavelength = 532 nm, Fluence ˜110 J/cm2, spot size ˜5 mm). A single-column tensiometer, interfaced with a personal computer, tested the bonding strength. K-type thermocouples recorded the temperature (T) at the adhesive-tissue interface during laser irradiation. Human fibroblasts were also seeded on the adhesive and cultured for 48 hours to assess cell growth. Results and Conclusion. The RB-chitosan adhesive bonded firmly to the intestine (15±2 kPa, n = 31). The adhesion strength dropped to 0.5±0.1 kPa (n = 8) when the laser was not applied to the adhesive. The average temperature of the adhesive increased from 26 °C to 32 °C during laser exposure. Fibroblasts grew confluent on the adhesive without morphological changes. A new