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Sample records for fibronectin drives focal

  1. Micrometer scale spacings between fibronectin nanodots regulate cell morphology and focal adhesions

    NASA Astrophysics Data System (ADS)

    Horzum, Utku; Ozdil, Berrin; Pesen-Okvur, Devrim

    2014-04-01

    Cell adhesion to extracellular matrix is an important process for both health and disease states. Surface protein patterns that are topographically flat, and do not introduce other chemical, topographical or rigidity related functionality and, more importantly, that mimic the organization of the in vivo extracellular matrix are desired. Previous work showed that vinculin and cytoskeletal organization are modulated by size and shape of surface nanopatterns. However, quantitative analysis on cell morphology and focal adhesions as a function of micrometer scale spacings of FN nanopatterns was absent. Here, electron beam lithography was used to pattern fibronectin nanodots with micrometer scale spacings on a K-casein background on indium tin oxide coated glass which, unlike silicon, is transparent and thus suitable for many light microscopy techniques. Exposure times were significantly reduced using the line exposure mode with micrometer scale step sizes. Micrometer scale spacings of 2, 4 and 8 μm between fibronectin nanodots proved to modulate cell adhesion through modification of cell area, focal adhesion number, size and circularity. Overall, cell behavior was shown to shift at the apparent threshold of 4 μm spacing. The findings presented here offer exciting new opportunities for cell biology research.

  2. Mechanotransduction through fibronectin-integrin focal adhesion in microvascular smooth muscle cells: is calcium essential?

    PubMed Central

    Li, Zhaohui; Meininger, Gerald A.

    2012-01-01

    It is believed that increased transmural pressure exerts force on vascular smooth muscle cells (VSMCs) and triggers Ca2+ signaling as an initiating event responsible for the arteriolar myogenic response. However, the mechanisms linking the pressure increase to Ca2+ signaling are unclear. We have shown previously using atomic force microscopy (AFM) that mechanical force induces a VSMC contractile response when applied to single fibronectin (FN; Sun Z, Martinez-Lemus LA, Hill MA, Meininger GA. Am J Physiol Cell Physiol 295; C268–C278, 2008) focal adhesion sites. This current study seeks to determine whether application of force to single focal adhesions can cause a change in VSMC Ca2+. Experiments were performed in low passage (p3∼10) as well as in freshly isolated skeletal muscle arteriole VSMCs. AFM-attached microbeads (5 μm) were coated with FN or collagen type I (CN-I) or type IV (CN-IV) and placed on a VSMC for 20 min, resulting in formation of a focal adhesion between the cell and the microbead. In low passage VSMCs, mechanically pulling on the FN-coated beads (800∼3000 pN) did not induce a Ca2+ increase but did cause a contractile response. In freshly isolated VSMCs, application of an FN or CN-I-coated bead onto the cell surface induced global Ca2+ increases. However, these Ca2+ increases were not correlated with the application of AFM pulling force to the bead or with the VSMC contractile responses to FN-coupled pulling. Chelating cytosolic Ca2+ using BAPTA loading had no negative effect on the focal adhesion-related contractile response in both freshly isolated and low passage VSMCs, while the Rho-kinase inhibitor Y27632 abolished the micromyogenic response in both cases. These observations suggest that, in freshly isolated and cultured VSMCs, application of mechanical force to a focal adhesion does not invoke an acute global Ca2+ increase. On the other hand, our data support a role for Rho-linked signaling mechanism involved in mechanotransduction

  3. Full-Length Fibronectin Drives Fibroblast Accumulation at the Surface of Collagen Microtissues during Cell-Induced Tissue Morphogenesis.

    PubMed

    Foolen, Jasper; Shiu, Jau-Ye; Mitsi, Maria; Zhang, Yang; Chen, Christopher S; Vogel, Viola

    2016-01-01

    Generating and maintaining gradients of cell density and extracellular matrix (ECM) components is a prerequisite for the development of functionality of healthy tissue. Therefore, gaining insights into the drivers of spatial organization of cells and the role of ECM during tissue morphogenesis is vital. In a 3D model system of tissue morphogenesis, a fibronectin-FRET sensor recently revealed the existence of two separate fibronectin populations with different conformations in microtissues, i.e. 'compact and adsorbed to collagen' versus 'extended and fibrillar' fibronectin that does not colocalize with the collagen scaffold. Here we asked how the presence of fibronectin might drive this cell-induced tissue morphogenesis, more specifically the formation of gradients in cell density and ECM composition. Microtissues were engineered in a high-throughput model system containing rectangular microarrays of 12 posts, which constrained fibroblast-populated collagen gels, remodeled by the contractile cells into trampoline-shaped microtissues. Fibronectin's contribution during the tissue maturation process was assessed using fibronectin-knockout mouse embryonic fibroblasts (Fn-/- MEFs) and floxed equivalents (Fnf/f MEFs), in fibronectin-depleted growth medium with and without exogenously added plasma fibronectin (full-length, or various fragments). In the absence of full-length fibronectin, Fn-/- MEFs remained homogenously distributed throughout the cell-contracted collagen gels. In contrast, in the presence of full-length fibronectin, both cell types produced shell-like tissues with a predominantly cell-free compacted collagen core and a peripheral surface layer rich in cells. Single cell assays then revealed that Fn-/- MEFs applied lower total strain energy on nanopillar arrays coated with either fibronectin or vitronectin when compared to Fnf/f MEFs, but that the presence of exogenously added plasma fibronectin rescued their contractility. While collagen decoration of

  4. Full-Length Fibronectin Drives Fibroblast Accumulation at the Surface of Collagen Microtissues during Cell-Induced Tissue Morphogenesis

    PubMed Central

    Foolen, Jasper; Shiu, Jau-Ye; Mitsi, Maria; Zhang, Yang; Chen, Christopher S.; Vogel, Viola

    2016-01-01

    Generating and maintaining gradients of cell density and extracellular matrix (ECM) components is a prerequisite for the development of functionality of healthy tissue. Therefore, gaining insights into the drivers of spatial organization of cells and the role of ECM during tissue morphogenesis is vital. In a 3D model system of tissue morphogenesis, a fibronectin-FRET sensor recently revealed the existence of two separate fibronectin populations with different conformations in microtissues, i.e. ‘compact and adsorbed to collagen’ versus ‘extended and fibrillar’ fibronectin that does not colocalize with the collagen scaffold. Here we asked how the presence of fibronectin might drive this cell-induced tissue morphogenesis, more specifically the formation of gradients in cell density and ECM composition. Microtissues were engineered in a high-throughput model system containing rectangular microarrays of 12 posts, which constrained fibroblast-populated collagen gels, remodeled by the contractile cells into trampoline-shaped microtissues. Fibronectin’s contribution during the tissue maturation process was assessed using fibronectin-knockout mouse embryonic fibroblasts (Fn-/- MEFs) and floxed equivalents (Fnf/f MEFs), in fibronectin-depleted growth medium with and without exogenously added plasma fibronectin (full-length, or various fragments). In the absence of full-length fibronectin, Fn-/- MEFs remained homogenously distributed throughout the cell-contracted collagen gels. In contrast, in the presence of full-length fibronectin, both cell types produced shell-like tissues with a predominantly cell-free compacted collagen core and a peripheral surface layer rich in cells. Single cell assays then revealed that Fn-/- MEFs applied lower total strain energy on nanopillar arrays coated with either fibronectin or vitronectin when compared to Fnf/f MEFs, but that the presence of exogenously added plasma fibronectin rescued their contractility. While collagen

  5. Introduction of four different drive systems used in LAMOST focal plane

    NASA Astrophysics Data System (ADS)

    Wang, Guomin; Jiang, Xiang; Wang, Yuefei; Li, Guoping; Gu, Bozhong

    2006-06-01

    This paper describes four different drive systems adopted in LAMOST focal plane mechanism to achieve four movements: field derotation, focal plane attitude adjustment, focusing and move aside out of light path for optical checking. Different type drive systems, such as worm gear drive, spur gear drive, friction drive and direct drive, which were devised and used in telescopes in the past years, have their own inherent characteristics and their working conditions. According to feasibility, reliability, suitability and cost effective, friction drive, worm gear drive, ball screw drive and chain drive are selected to as the drive systems for the above four movements. The on-shop test results show that all the drive systems have met the design goals with the accuracy of image field derotation 0.45 arcsec, attitude adjustment 0.24 arcsec, focusing 2 microns and move aside 0.02mm.

  6. SYSTEMATIC ANALYSIS OF REAL-WORLD DRIVING BEHAVIOR FOLLOWING FOCAL BRAIN LESIONS

    PubMed Central

    Thompson, Kelsey; Read, Katherine; Anderson, Steven; Rizzo, Matthew

    2012-01-01

    Summary Many patients with circumscribed brain injuries, such as those caused by stroke or focal trauma, return to driving after a period of acute recovery. These persons often have chronic residual cognitive deficits that may impact on driving safety, but little is known about their driving behavior in the real world. Extant studies tend to rely on driving simulators or controlled on-road drives. These methods of observation are not able to capture the complexities of the typical driving environment, and may not accurately represent a driver’s usual behavior on the road. The current study used a video event-activated data recorder (VEADR) system to observe drivers with focal brain lesions in their normal daily driving environment over a three-month period. In the context of primarily safe driving behavior, we were able to document a number of relatively infrequent and hitherto unobserved high risk behaviors and traffic violations. These findings demonstrate the feasibility and value of sampling real-world driving in neurologic patient populations such as those with focal brain lesions, and highlight the critical importance of evaluating unsafe driving behaviors which may occur with insufficient frequency to be captured by relatively brief simulator or controlled on-road evaluations. PMID:25309966

  7. Fast focal zooming scheme for direct drive fusion implemented by inserting KD2PO4 crystal

    NASA Astrophysics Data System (ADS)

    Zhong, Zheqiang; Hu, Xiaochuan; Zhang, Bin

    2016-06-01

    The highly required uniformity of target in direct-drive fusion is difficult to achieve and maintain during the entire laser fusion implosion. To mitigate the increasing nonuniformity, the fast focal zooming scheme implemented by inserting an electro-optic (EO) crystal in the front end of beamline has been proposed. Functioning as a phase plate, the specifically designed EO crystal may add the induced spherical wavefront to the laser beam and alter its focusing characteristics. However, in order to zoom out the focal spot by half, the required voltage for KD2PO4 (DKDP) with single pair of electrodes is relatively high. In order to decrease the voltage while maintaining the zooming performance, the DKDP cylinder with multi pairs of electrodes has been presented. The continuous phase plate (CPP) is designed according to both the injected beam and the output field. However, the conventional CPP is designed based on the assumption of an injected beam without wavefront distortion, which would zoom in the focal spot variation in the focal zooming scheme. In order to zoom out the focal spot, a redesigned CPP has been proposed by adding a spherical wavefront to the phase variation of the conventional CPP and further optimizing. On the basis, the focusing characteristics of laser beam during the fast focal zooming process have been analyzed. Results indicate that the focal spot size decreases with the increasing voltage on DKDP crystal, meanwhile the uniformity maintains high during the focal zooming process.

  8. Whole-genome plasma sequencing reveals focal amplifications as a driving force in metastatic prostate cancer

    PubMed Central

    Ulz, Peter; Belic, Jelena; Graf, Ricarda; Auer, Martina; Lafer, Ingrid; Fischereder, Katja; Webersinke, Gerald; Pummer, Karl; Augustin, Herbert; Pichler, Martin; Hoefler, Gerald; Bauernhofer, Thomas; Geigl, Jochen B.; Heitzer, Ellen; Speicher, Michael R.

    2016-01-01

    Genomic alterations in metastatic prostate cancer remain incompletely characterized. Here we analyse 493 prostate cancer cases from the TCGA database and perform whole-genome plasma sequencing on 95 plasma samples derived from 43 patients with metastatic prostate cancer. From these samples, we identify established driver aberrations in a cancer-related gene in nearly all cases (97.7%), including driver gene fusions (TMPRSS2:ERG), driver focal deletions (PTEN, RYBP and SHQ1) and driver amplifications (AR and MYC). In serial plasma analyses, we observe changes in focal amplifications in 40% of cases. The mean time interval between new amplifications was 26.4 weeks (range: 5–52 weeks), suggesting that they represent rapid adaptations to selection pressure. An increase in neuron-specific enolase is accompanied by clonal pattern changes in the tumour genome, most consistent with subclonal diversification of the tumour. Our findings suggest a high plasticity of prostate cancer genomes with newly occurring focal amplifications as a driving force in progression. PMID:27328849

  9. Whole-genome plasma sequencing reveals focal amplifications as a driving force in metastatic prostate cancer.

    PubMed

    Ulz, Peter; Belic, Jelena; Graf, Ricarda; Auer, Martina; Lafer, Ingrid; Fischereder, Katja; Webersinke, Gerald; Pummer, Karl; Augustin, Herbert; Pichler, Martin; Hoefler, Gerald; Bauernhofer, Thomas; Geigl, Jochen B; Heitzer, Ellen; Speicher, Michael R

    2016-01-01

    Genomic alterations in metastatic prostate cancer remain incompletely characterized. Here we analyse 493 prostate cancer cases from the TCGA database and perform whole-genome plasma sequencing on 95 plasma samples derived from 43 patients with metastatic prostate cancer. From these samples, we identify established driver aberrations in a cancer-related gene in nearly all cases (97.7%), including driver gene fusions (TMPRSS2:ERG), driver focal deletions (PTEN, RYBP and SHQ1) and driver amplifications (AR and MYC). In serial plasma analyses, we observe changes in focal amplifications in 40% of cases. The mean time interval between new amplifications was 26.4 weeks (range: 5-52 weeks), suggesting that they represent rapid adaptations to selection pressure. An increase in neuron-specific enolase is accompanied by clonal pattern changes in the tumour genome, most consistent with subclonal diversification of the tumour. Our findings suggest a high plasticity of prostate cancer genomes with newly occurring focal amplifications as a driving force in progression. PMID:27328849

  10. Three-dimensional imaging system by using a low-voltage-driving LC lens with a tunable focal length

    NASA Astrophysics Data System (ADS)

    Kawamura, Marenori; Ishikuro, Shunsuke

    2015-09-01

    We develop a three-dimensional imaging system by using a low-voltage-driving liquid crystal (LC) lens for determining depth mapping properties of three-dimensional objects. The sequential photo images without the magnification and reduction are taken by electrically controlling a focal plane along a depth direction with no mechanical movements. The depth mapping properties can be obtained by processing an image digital filter from the different focal images.

  11. Inverted formin 2 in focal adhesions promotes dorsal stress fiber and fibrillar adhesion formation to drive extracellular matrix assembly

    PubMed Central

    Skau, Colleen T.; Plotnikov, Sergey V.; Doyle, Andrew D.; Waterman, Clare M.

    2015-01-01

    Actin filaments and integrin-based focal adhesions (FAs) form integrated systems that mediate dynamic cell interactions with their environment or other cells during migration, the immune response, and tissue morphogenesis. How adhesion-associated actin structures obtain their functional specificity is unclear. Here we show that the formin-family actin nucleator, inverted formin 2 (INF2), localizes specifically to FAs and dorsal stress fibers (SFs) in fibroblasts. High-resolution fluorescence microscopy and manipulation of INF2 levels in cells indicate that INF2 plays a critical role at the SF–FA junction by promoting actin polymerization via free barbed end generation and centripetal elongation of an FA-associated actin bundle to form dorsal SF. INF2 assembles into FAs during maturation rather than during their initial generation, and once there, acts to promote rapid FA elongation and maturation into tensin-containing fibrillar FAs in the cell center. We show that INF2 is required for fibroblasts to organize fibronectin into matrix fibers and ultimately 3D matrices. Collectively our results indicate an important role for the formin INF2 in specifying the function of fibrillar FAs through its ability to generate dorsal SFs. Thus, dorsal SFs and fibrillar FAs form a specific class of integrated adhesion-associated actin structure in fibroblasts that mediates generation and remodeling of ECM. PMID:25918420

  12. Fibronectin and craniofacial surgery.

    PubMed

    Al-Qattan, Mohammad M; AlShomer, Feras; Alqahtani, Abdullah; Alhadlg, Ahmad

    2014-12-01

    Fibronectin is an essential component of the extracellular matrix. The role of fibronectin in craniofacial surgery has not been previously reviewed. Fibronectin mediates bone differentiation and development of the skull. Studies have shown that normal development of the skull requires a specific pattern of expression around the epithelial-mesenchymal interface of the neurocranium. Fibronectin is also essential in mediating the migration of neural crest cells to form the facial skeleton. The calvaria of patients with Apert and Crouzon syndromes have an abnormally elevated collagen level. However, fibronectin levels are elevated in the former syndrome and decreased in the latter syndrome. The significance of this requires further research. Fibronectin gene expression is increased in port wine-derived fibroblasts in patients with Sturge-Weber syndrome. Normal palatogenesis also requires a specific pattern of expression of fibronectin around the maxillary process as well as the roof of the stomodeum, and several studies have linked the development of cleft lip/palate to an imbalance of fibronectin content of the extracellular matrix. Fibronectin mediates cell-to-cell attachment during repair of calvarial defects; hence, fibronectin has been used as a carrier for bone morphogenetic proteins to treat calvarial defects. Finally, fibronectin is now an essential component in stem cell technology related to craniofacial surgery. PMID:24322634

  13. Haematopoietic focal adhesion kinase deficiency alters haematopoietic homeostasis to drive tumour metastasis.

    PubMed

    Batista, Silvia; Maniati, Eleni; Reynolds, Louise E; Tavora, Bernardo; Lees, Delphine M; Fernandez, Isabelle; Elia, George; Casanovas, Oriol; Lo Celso, Cristina; Hagemann, Thorsten; Hodivala-Dilke, Kairbaan

    2014-01-01

    Metastasis is the main cause of cancer-related death and thus understanding the molecular and cellular mechanisms underlying this process is critical. Here, our data demonstrate, contrary to established dogma, that loss of haematopoietic-derived focal adhesion kinase (FAK) is sufficient to enhance tumour metastasis. Using both experimental and spontaneous metastasis models, we show that genetic ablation of haematopoietic FAK does not affect primary tumour growth but enhances the incidence of metastasis significantly. At a molecular level, haematopoietic FAK deletion results in an increase in PU-1 levels and decrease in GATA-1 levels causing a shift of hematopoietic homeostasis towards a myeloid commitment. The subsequent increase in circulating granulocyte number, with an increase in serum CXCL12 and granulocyte CXCR4 levels, was required for augmented metastasis in mice lacking haematopoietic FAK. Overall our findings provide a mechanism by which haematopoietic FAK controls cancer metastasis. PMID:25270220

  14. Quantitative changes in focal adhesion kinase and its inhibitor, FRNK, drive load-dependent expression of costamere components.

    PubMed

    Klossner, Stephan; Li, Ruowei; Ruoss, Severin; Durieux, Anne-Cécile; Flück, Martin

    2013-09-15

    Costameres are mechanosensory sites of focal adhesion in the sarcolemma that reinforce the muscle-fiber composite and provide an anchor for myofibrillogenesis. We hypothesized that elevated content of the integrin-associated regulator of costamere turnover in culture, focal adhesion kinase (FAK), drives changes in costamere component content in antigravity muscle in a load-dependent way in correspondence with altered muscle weight. The content of FAK in soleus muscle being phosphorylated at autoregulatory tyrosine 397 (FAK-pY397) was increased after 20 s of stretch. FAK-pY397 content remained elevated after 24 h of stretch-overload due to upregulated FAK content. Overexpression of FAK in soleus muscle fibers by means of gene electrotransfer increased the β1-integrin (+56%) and meta-vinculin (+88%) content. α7-Integrin (P = 0.46) and γ-vinculin (P = 0.18) content was not altered after FAK overexpression. Co-overexpression of the FAK inhibitor FAK-related nonkinase (FRNK) reduced FAK-pY397 content by 33% and increased the percentage of fast-type fibers that arose in connection with hybrid fibers with gene transfer. Transplantation experiments confirmed the association of FRNK expression with slow-to-fast fiber transformation. Seven days of unloading blunted the elevation of FAK-pY397, β1-integrin, and meta-vinculin content with FAK overexpression, and this was reversed by 1 day of reloading. The results highlight that the expression of components for costameric attachment sites of myofibrils is under load- and fiber type-related control via FAK and its inhibitor FRNK. PMID:23904105

  15. Fibronectin adsorption, cell adhesion, and proliferation on nanostructured tantalum surfaces.

    PubMed

    Dolatshahi-Pirouz, A; Jensen, T; Kraft, David Christian; Foss, Morten; Kingshott, Peter; Hansen, John Lundsgaard; Larsen, Arne Nylandsted; Chevallier, Jacques; Besenbacher, Flemming

    2010-05-25

    The interaction between dental pulp derived mesenchymal stem cells (DP-MSCs) and three different tantalum nanotopographies with and without a fibronectin coating is examined: sputter-coated tantalum surfaces with low surface roughness <0.2 nm, hut-nanostructured surfaces with a height of 2.9 +/- 0.6 nm and a width of 35 +/- 8 nm, and dome structures with a height of 13 +/- 2 nm and a width of 52 +/- 14 nm. Using ellipsometry, the adsorption and the availability of fibronectin cell-binding domains on the tantalum surfaces were examined, as well as cellular attachment, proliferation, and vinculin focal adhesion spot assembly on the respective surfaces. The results showed the highest fibronectin mass uptake on the hut structures, with a slightly higher availability of cell-binding domains and the most pronounced formation of vinculin focal adhesion spots as compared to the other surfaces. The proliferation of DP-MSCs was found to be significantly higher on dome and hut surfaces coated with fibronectin compared to the uncoated flat tantalum surfaces. Consequently, the results presented in this study indicate that fibronectin-coated nanotopographies with a vertical dimension of less than 5 nm influence cell adhesion. This rather interesting behavior is argued to originate from the more available fibronectin cell-binding domains observed on the hut structures. PMID:20443575

  16. Fibronectin regulates calvarial osteoblast differentiation

    NASA Technical Reports Server (NTRS)

    Moursi, A. M.; Damsky, C. H.; Lull, J.; Zimmerman, D.; Doty, S. B.; Aota, S.; Globus, R. K.

    1996-01-01

    The secretion of fibronectin by differentiating osteoblasts and its accumulation at sites of osteogenesis suggest that fibronectin participates in bone formation. To test this directly, we determined whether fibronectin-cell interactions regulate progressive differentiation of cultured fetal rat calvarial osteoblasts. Spatial distributions of alpha 5 integrin subunit, fibronectin, osteopontin (bone sialoprotein I) and osteocalcin (bone Gla-protein) were similar in fetal rat calvaria and mineralized, bone-like nodules formed by cultured osteoblasts. Addition of anti-fibronectin antibodies to cultures at confluence reduced subsequent formation of nodules to less than 10% of control values, showing that fibronectin is required for normal nodule morphogenesis. Anti-fibronectin antibodies selectively inhibited steady-state expression of mRNA for genes associated with osteoblast differentiation; mRNA levels for alkaline phosphatase and osteocalcin were suppressed, whereas fibronectin, type I collagen and osteopontin were unaffected. To identify functionally relevant domains of fibronectin, we treated cells with soluble fibronectin fragments and peptides. Cell-binding fibronectin fragments (type III repeats 6-10) containing the Arg-Gly-Asp (RGD) sequence blocked both nodule initiation and maturation, whether or not they contained a functional synergy site. In contrast, addition of the RGD-containing peptide GRGDSPK alone did not inhibit nodule initiation, although it did block nodule maturation. Thus, in addition to the RGD sequence, other features of the large cell-binding fragments contribute to the full osteogenic effects of fibronectin. Nodule formation and osteoblast differentiation resumed after anti-fibronectin antibodies or GRGDSPK peptides were omitted from the media, showing that the inhibition was reversible and the treatments were not cytotoxic. Outside the central cell-binding domain, peptides from the IIICS region and antibodies to the N terminus did not

  17. THE α4β1 INTEGRIN AND THE EDA DOMAIN OF FIBRONECTIN REGULATE A PROFIBROTIC PHENOTYPE IN DERMAL FIBROBLASTS*

    PubMed Central

    Shinde, Arti V.; Kelsh, Rhiannon; Peters, John H.; Sekiguchi, Kiyotoshi; Van De Water, Livingston; McKeown-Longo, Paula J.

    2015-01-01

    Prompt deposition of fibronectin-rich extracellular matrix is a critical feature of normal development and the host-response to injury. Fibronectin isoforms that include the EDA and EDB domains are prominent in these fibronectin matrices. We now report using human dermal fibroblast cultures that the EDA domain of fibronectin or EDA-derived peptides modeled after the C-C’ loop promote stress fiber formation and myosin-light chain phosphorylation. These changes are accompanied by an increase in fibronectin synthesis and fibrillogenesis. These effects are blocked by pretreating cells with either siRNA or blocking antibody to the α4 integrin. Our data indicate that the interaction between the α4β1 integrin and the EDA domain of fibronectin helps to drive tissue fibrosis by promoting a contractile phenotype and an increase in fibronectin synthesis and deposition. PMID:25433338

  18. The α4β1 integrin and the EDA domain of fibronectin regulate a profibrotic phenotype in dermal fibroblasts.

    PubMed

    Shinde, Arti V; Kelsh, Rhiannon; Peters, John H; Sekiguchi, Kiyotoshi; Van De Water, Livingston; McKeown-Longo, Paula J

    2015-01-01

    Prompt deposition of fibronectin-rich extracellular matrix is a critical feature of normal development and the host-response to injury. Fibronectin isoforms that include the EDA and EDB domains are prominent in these fibronectin matrices. We now report using human dermal fibroblast cultures that the EDA domain of fibronectin or EDA-derived peptides modeled after the C-C' loop promote stress fiber formation and myosin-light chain phosphorylation. These changes are accompanied by an increase in fibronectin synthesis and fibrillogenesis. These effects are blocked by pretreating cells with either siRNA or blocking antibody to the α4 integrin. Our data indicate that the interaction between the α4β1 integrin and the EDA domain of fibronectin helps to drive tissue fibrosis by promoting a contractile phenotype and an increase in fibronectin synthesis and deposition. PMID:25433338

  19. Dynamic Structure of Plasma Fibronectin

    PubMed Central

    Maurer, Lisa M.; Ma, Wenjiang; Mosher, Deane F.

    2016-01-01

    Fibronectin is a large vertebrate glycoprotein that is found in soluble and insoluble forms and involved in diverse processes. Protomeric fibronectin is a dimer of subunits, each of which comprises 29 to 31 modules—12 type I, two type II, and 15-17 type III. Plasma fibronectin is secreted by hepatocytes and circulates in a compact conformation before it binds to cell surfaces, converts to an extended conformation, and is assembled into fibronectin fibrils. Here we review biophysical and structural studies that have shed light on how plasma fibronectin transitions from the compact to the extended conformation. The three types of modules each have a well-organized secondary and tertiary structure as defined by NMR and crystallography and have been likened to “beads on a string”. There are flexible sequences in the N-terminal tail, between the fifth and sixth type I modules, between the first two and last two of the type III modules, and at the C-terminus. Several specific module-module interactions have been identified that likely maintain the compact quaternary structure of circulating fibronectin. The quaternary structure is perturbed in response to binding events, including binding of fibronectin to the surface of vertebrate cells for fibril assembly and to bacterial adhesins. PMID:27185500

  20. Collagenofibrotic glomerulonephropathy with fibronectin deposition in a dog.

    PubMed

    Kamiie, J; Yasuno, K; Ogihara, K; Nakamura, A; Tamahara, S; Fujino, Y; Ono, K; Shirota, K

    2009-07-01

    We report herein a case of collagenofibrotic glomerulonephropathy in a 3-year-old Shiba Inu with severe proteinuria. Histologically, renal glomeruli were enlarged with massive deposition of a homogeneous eosinophilic substance within the mesangium and capillary walls. The deposits reacted weakly with periodic acid-Schiff, stained deep blue with Masson's trichrome, and were positive by immunofluorescence for type III collagen and fibronectin. Ultrastructurally, the deposits consisted of fibrils and amorphous material in the mesangial matrix and beneath the glomerular capillary endothelium. The fibrils had transverse bands analogous to those of collagen fibrils. Electron microscopy also revealed focal detachment of podocytes and foot process effacement in glomerular tufts, which suggested that podocyte injury had contributed to the development of proteinuria in this dog. The current case resembles collagenofibrotic glomerulonephropathy (CFGN) in humans in histopathologic, immunofluorescence, and electron microscopic findings. This is the first report of CFGN in a nonhuman species with glomerular deposition of fibronectin and type III collagen. PMID:19276051

  1. Genetics Home Reference: fibronectin glomerulopathy

    MedlinePlus

    ... any age. It eventually leads to irreversible kidney failure (end-stage renal disease). Individuals with fibronectin glomerulopathy usually have blood ... Health Topic: High Blood Pressure Health Topic: Kidney Failure ... Renal Disease (ESRD) KidsHealth from Nemours: Renal Tubular Acidosis ...

  2. Engineering of Self-Assembled Fibronectin Matrix Protein and Its Effects on Mesenchymal Stem Cells

    PubMed Central

    Yun, Ye-Rang; Pham, Le B. Hang; Yoo, Yie-Ri; Lee, Sujin; Kim, Hae-Won; Jang, Jun-Hyeog

    2015-01-01

    Fibronectin (FN) contributes to cell adhesion, proliferation, and differentiation in various cell types. To enhance the activity of fibronectin at the sites of focal adhesion, we engineered a novel recombinant fibronectin (FNIII10) fragment connected to the peptide amphiphile sequence (PA), LLLLLLCCCGGDS. In this study, the effects of FNIII10-PA on rat mesenchymal stem cells (rMSCs) were compared with those of FNIII10. FNIII10-PA showed the prominent protein adhesion activity. In addition, FNIII10-PA showed a significantly higher effect on adhesion, proliferation, and differentiation of rMSCs than FNIII10. Taken together, the FNIII10-containing self-assembled sequence enhanced rMSCs adhesion, proliferation, and differentiation. PMID:26295389

  3. Matrix Gla Protein Binds to Fibronectin and Enhances Cell Attachment and Spreading on Fibronectin

    PubMed Central

    Nishimoto, Satoru Ken; Nishimoto, Miyako

    2014-01-01

    Background. Matrix Gla protein (MGP) is a vitamin K-dependent, extracellular matrix protein. MGP is a calcification inhibitor of arteries and cartilage. However MGP is synthesized in many tissues and is especially enriched in embryonic tissues and in cancer cells. The presence of MGP in those instances does not correlate well with the calcification inhibitory role. This study explores a potential mechanism for MGP to bind to matrix proteins and alter cell matrix interactions. Methods. To determine whether MGP influences cell behavior through interaction with fibronectin, we studied MGP binding to fibronectin, the effect of MGP on fibronectin mediated cell attachment and spreading and immunolocalized MGP and fibronectin. Results. First, MGP binds to fibronectin. The binding site for MGP is in a specific fibronectin fragment, called III1-C or anastellin. The binding site for fibronectin is in a MGP C-terminal peptide comprising amino acids 61–77. Second, MGP enhances cell attachment and cell spreading on fibronectin. MGP alone does not promote cell adhesion. Third, MGP is present in fibronectin-rich regions of tissue sections. Conclusions. MGP binds to fibronectin. The presence of MGP increased cell-fibronectin interactions. PMID:25210519

  4. The evolution of tenascins and fibronectin

    PubMed Central

    Adams, Josephine C; Chiquet-Ehrismann, Ruth; Tucker, Richard P

    2015-01-01

    Tenascins are extracellular matrix glycoproteins that act both as integrin ligands and as modifiers of fibronectin-integrin interactions to regulate cell adhesion, migration, proliferation and differentiation. In tetrapods, both tenascins and fibronectin bind to integrins via RGD and LDV-type tripeptide motifs found in exposed loops in their fibronectin-type III domains. We previously showed that tenascins appeared early in the chordate lineage and are represented by single genes in extant cephalochordates and tunicates. Here we have examined the genomes of the coelacanth Latimeria chalumnae, the elephant shark Callorhinchus milii as well as the lampreys Petromyzon marinus and Lethenteron japonicum to learn more about the evolution of the tenascin gene family as well as the timing of the appearance of fibronectin during chordate evolution. The coelacanth has 4 tenascins that are more similar to tetrapod tenascins than are tenascins from ray-finned fishes. In contrast, only 2 tenascins were identified in the elephant shark and the Japanese lamprey L. japonicum. An RGD motif exposed to integrin binding is observed in tenascins from many, but not all, classes of chordates. Tetrapods that lack this RGD motif in tenascin-C have a similar motif in the paralog tenascin-W, suggesting the potential for some overlapping function. A predicted fibronectin with the same domain organization as the fibronectin from tetrapods is found in the sea lamprey P. marinus but not in tunicates, leading us to infer that fibronectin first appeared in vertebrates. The motifs that recognize LDV-type integrin receptors are conserved in fibronectins from a broad spectrum of vertebrates, but the RGD integrin-binding motif may have evolved in gnathostomes. PMID:25482621

  5. The evolution of tenascins and fibronectin.

    PubMed

    Adams, Josephine C; Chiquet-Ehrismann, Ruth; Tucker, Richard P

    2015-01-01

    Tenascins are extracellular matrix glycoproteins that act both as integrin ligands and as modifiers of fibronectin-integrin interactions to regulate cell adhesion, migration, proliferation and differentiation. In tetrapods, both tenascins and fibronectin bind to integrins via RGD and LDV-type tripeptide motifs found in exposed loops in their fibronectin-type III domains. We previously showed that tenascins appeared early in the chordate lineage and are represented by single genes in extant cephalochordates and tunicates. Here we have examined the genomes of the coelacanth Latimeria chalumnae, the elephant shark Callorhinchus milii as well as the lampreys Petromyzon marinus and Lethenteron japonicum to learn more about the evolution of the tenascin gene family as well as the timing of the appearance of fibronectin during chordate evolution. The coelacanth has 4 tenascins that are more similar to tetrapod tenascins than are tenascins from ray-finned fishes. In contrast, only 2 tenascins were identified in the elephant shark and the Japanese lamprey L. japonicum. An RGD motif exposed to integrin binding is observed in tenascins from many, but not all, classes of chordates. Tetrapods that lack this RGD motif in tenascin-C have a similar motif in the paralog tenascin-W, suggesting the potential for some overlapping function. A predicted fibronectin with the same domain organization as the fibronectin from tetrapods is found in the sea lamprey P. marinus but not in tunicates, leading us to infer that fibronectin first appeared in vertebrates. The motifs that recognize LDV-type integrin receptors are conserved in fibronectins from a broad spectrum of vertebrates, but the RGD integrin-binding motif may have evolved in gnathostomes. PMID:25482621

  6. Fibronectin phosphorylation by ecto-protein kinase

    SciTech Connect

    Imada, Sumi; Sugiyama, Yayoi; Imada, Masaru )

    1988-12-01

    The presence of membrane-associated, extracellular protein kinase (ecto-protein kinase) and its substrate proteins was examined with serum-free cultures of Swiss 3T3 fibroblast. When cells were incubated with ({gamma}-{sup 32})ATP for 10 min at 37{degree}C, four proteins with apparent molecular weights between 150 and 220 kDa were prominently phosphorylated. These proteins were also radiolabeled by lactoperoxidase catalyzed iodination and were sensitive to mild tryptic digestion, suggesting that they localized on the cell surface or in the extracellular matrix. Phosphorylation of extracellular proteins with ({gamma}-{sup 32}P)ATP in intact cell culture is consistent with the existence of ecto-protein kinase. Anti-fibronectin antibody immunoprecipitated one of the phosphoproteins which comigrated with a monomer and a dimer form of fibronectin under reducing and nonreducing conditions of electrophoresis, respectively. The protein had affinity for gelatin as demonstrated by retention with gelatin-conjugated agarose. This protein substrate of ecto-protein kinase was thus concluded to be fibronectin. The sites of phosphorylation by ecto-protein kinase were compared with those of intracellularly phosphorylated fibronectin by the analysis of radiolabeled amino acids and peptides. Ecto-protein kinase phosphorylated fibronectin at serine and threonine residues which were distinct from the sites of intracellular fibronectin phosphorylation.

  7. Dynamic Modeling of Cell Migration and Spreading Behaviors on Fibronectin Coated Planar Substrates and Micropatterned Geometries

    PubMed Central

    Kim, Min-Cheol; Neal, Devin M.; Kamm, Roger D.; Asada, H. Harry

    2013-01-01

    An integrative cell migration model incorporating focal adhesion (FA) dynamics, cytoskeleton and nucleus remodeling, actin motor activity, and lamellipodia protrusion is developed for predicting cell spreading and migration behaviors. This work is motivated by two experimental works: (1) cell migration on 2-D substrates under various fibronectin concentrations and (2) cell spreading on 2-D micropatterned geometries. These works suggest (1) cell migration speed takes a maximum at a particular ligand density (∼1140 molecules/µm2) and (2) that strong traction forces at the corners of the patterns may exist due to combined effects exerted by actin stress fibers (SFs). The integrative model of this paper successfully reproduced these experimental results and indicates the mechanism of cell migration and spreading. In this paper, the mechanical structure of the cell is modeled as having two elastic membranes: an outer cell membrane and an inner nuclear membrane. The two elastic membranes are connected by SFs, which are extended from focal adhesions on the cortical surface to the nuclear membrane. In addition, the model also includes ventral SFs bridging two focal adhesions on the cell surface. The cell deforms and gains traction as transmembrane integrins distributed over the outer cell membrane bond to ligands on the ECM surface, activate SFs, and form focal adhesions. The relationship between the cell migration speed and fibronectin concentration agrees with existing experimental data for Chinese hamster ovary (CHO) cell migrations on fibronectin coated surfaces. In addition, the integrated model is validated by showing persistent high stress concentrations at sharp geometrically patterned edges. This model will be used as a predictive model to assist in design and data processing of upcoming microfluidic cell migration assays. PMID:23468612

  8. High-affinity binding of fibronectin to cultured Kupffer cells

    SciTech Connect

    Cardarelli, P.M.; Blumenstock, F.A.; McKeown-Longo, P.J.; Saba, T.M.; Mazurkiewicz, J.E.; Dias, J.A. )

    1990-11-01

    Hepatic Kupffer cells are a major component of the reticuloendothelial or macrophage system. They were the first phagocytic cell type whose phagocytosis was shown to be influenced by plasma fibronectin, a dimeric opsonic glycoprotein. In the current study, the binding of soluble radioiodinated fibronectin purified from rat serum to isolated rat hepatic Kupffer cells was investigated using a cultured Kupffer cell monolayer technique. Binding was specific, since unlabeled purified fibronectin competed in a dose-dependent manner with the 125I-fibronectin for binding to the Kupffer cells. Addition of gelatin enhanced the binding of 125I-fibronectin to Kupffer cells. The phagocytosis of gelatinized-coated red cells by Kupffer cells was increased either by preopsonizing the target particles with purified fibronectin or by the addition of purified fibronectin to the culture medium. In contrast, exposure of the Kupffer cells to medium containing purified fibronectin followed by wash-removal of the fibronectin did not increase the uptake of gelatin-coated red blood cells, even though fibronectin was detected on the surface of the Kupffer cells by immunofluorescence. Trypsinized monolayers expressed decreased capacity to bind 125I-fibronectin as well as fibronectin-coated sheep erythrocytes. The binding of 125I-fibronectin-gelatin complexes was inhibited by excess unlabeled fibronectin. We calculated that specific high-affinity (Kd = 7.46 x 10(-9) M) binding sites for fibronectin exist on Kupffer cells. There are approximately 2,800-3,500 binding sites or putative fibronectin receptors per Kupffer cell. These sites appear to mediate the enhanced phagocytosis of gelatin-coated particles opsonized by fibronectin.

  9. Fibronectin is a survival factor for differentiated osteoblasts

    NASA Technical Reports Server (NTRS)

    Globus, R. K.; Doty, S. B.; Lull, J. C.; Holmuhamedov, E.; Humphries, M. J.; Damsky, C. H.

    1998-01-01

    The skeletal extracellular matrix produced by osteoblasts contains the glycoprotein fibronectin, which regulates the adhesion, differentiation and function of various adherent cells. Interactions with fibronectin are required for osteoblast differentiation in vitro, since fibronectin antagonists added to cultures of immature fetal calvarial osteoblasts inhibit their progressive differentiation. To determine if fibronectin plays a unique role in fully differentiated osteoblasts, cultures that had already formed mineralized nodules in vitro were treated with fibronectin antagonists. Fibronectin antibodies caused >95% of the cells in the mature cultures to display characteristic features of apoptosis (nuclear condensation, apoptotic body formation, DNA laddering) within 24 hours. Cells appeared to acquire sensitivity to fibronectin antibody-induced apoptosis as a consequence of differentiation, since antibodies failed to kill immature cells and the first cells killed were those associated with mature nodules. Intact plasma fibronectin, as well as fragments corresponding to the amino-terminal, cell-binding, and carboxy-terminal domains of fibronectin, independently induced apoptosis of mature (day-13), but not immature (day-4), osteoblasts. Finally, transforming growth factor-beta1 partially protected cells from the apoptotic effects of fibronectin antagonists. Thus, in the course of maturation cultured osteoblasts switch from depending on fibronectin for differentiation to depending on fibronectin for survival. These data suggest that fibronectin, together with transforming growth factor-beta1, may affect bone formation, in part by regulating the survival of osteoblasts.

  10. Fibronectin mediates mesendodermal cell fate decisions

    PubMed Central

    Cheng, Paul; Andersen, Peter; Hassel, David; Kaynak, Bogac L.; Limphong, Pattraranee; Juergensen, Lonny; Kwon, Chulan; Srivastava, Deepak

    2013-01-01

    Non-cell-autonomous signals often play crucial roles in cell fate decisions during animal development. Reciprocal signaling between endoderm and mesoderm is vital for embryonic development, yet the key signals and mechanisms remain unclear. Here, we show that endodermal cells efficiently promote the emergence of mesodermal cells in the neighboring population through signals containing an essential short-range component. The endoderm-mesoderm interaction promoted precardiac mesoderm formation in mouse embryonic stem cells and involved endodermal production of fibronectin. In vivo, fibronectin deficiency resulted in a dramatic reduction of mesoderm accompanied by endodermal expansion in zebrafish embryos. This event was mediated by regulation of Wnt signaling in mesodermal cells through activation of integrin-β1. Our findings highlight the importance of the extracellular matrix in mediating short-range signals and reveal a novel function of endoderm, involving fibronectin and its downstream signaling cascades, in promoting the emergence of mesoderm. PMID:23715551

  11. Formation of focal adhesion-stress fibre complexes coordinated by adhesive and non-adhesive surface domains.

    PubMed

    Zimerman, B; Arnold, M; Ulmer, J; Blümmel, J; Besser, A; Spatz, J P; Geiger, B

    2004-04-01

    Cell motility consists of repeating cycles of protrusion of a leading edge in the direction of migration, attachment of the advancing membrane to the matrix, and pulling of the trailing edge forward. In this dynamic process there is a major role for the cytoskeleton, which drives the protrusive events via polymerisation of actin in the lamellipodium, followed by actomyosin contractility. To study the transition of the actin cytoskeleton from a 'protrusive' to 'retractive' form, we have monitored the formation of focal adhesions and stress fibres during cell migration on a micro-patterned surface. This surface consisted of parallel arrays of 2 microm-wide, fibronectin-coated gold stripes, separated by non-adhesive (poly(ethylene glycol)-coated) glass areas with variable width, ranging from 4-12 microm. Monitoring the spreading of motile cells indicated that cell spreading was equally effective along and across the adhesive stripes, as long as the non-adhesive spaces between them did not exceed 6 microm. When the width of the PEG region was 8 microm or more, cells became highly polarised upon spreading, and failed to reach the neighboring adhesive stripes. It was also noted that as soon as the protruding lamella successfully crossed the PEG-coated area and reached an adhesive region, the organisation of actin in that area was transformed from a diffuse meshwork into a bundle, oriented perpendicularly to the stripes and anchored at its ends in focal adhesions. This transition depends on actomyosin-based contractility and is apparently triggered by the adhesion to the rigid fibronectin surface. PMID:16475844

  12. Ethanol Enhances the Interaction of Breast Cancer Cells Over-Expressing ErbB2 With Fibronectin

    PubMed Central

    Xu, Mei; Bower, Kimberly A.; Chen, Gang; Shi, Xianglin; Dong, Zheng; Ke, Zunji; Luo, Jia

    2016-01-01

    Background Ethanol is a tumor promoter and may enhance the metastasis of breast cancer. However, the underlying cellular / molecular mechanisms remain unknown. Amplification of ErbB2 or HER2, a receptor tyrosine kinase of the ErbB family, is found in 20 to 30% of patients with breast cancer. We have previously demonstrated that the effect of ethanol on the migration / invasion of breast cancer cells positively correlated with the expression levels of ErbB2. Adhesion to the extracellular matrix (ECM) is an important initial step for cancer cell invasion and metastasis. In this study, we investigated the effects of ethanol on the adhesion of MCF7 breast cancer cells over-expressing ErbB2 (MCF7ErbB2) to human plasma fibronectin. Methods To test the hypothesis that ethanol may enhance the attachment of human breast cancer cells to fibronectin, an important component of the ECM, we evaluated the effect of ethanol on the expression of focal adhesions, cell attachment, and ErbB2 signaling in cultured MCF7ErbB2 cells. Results Exposure to ethanol drastically enhanced the adhesion of MCFErbB2 cells to fibronectin and increased the expression of focal adhesions. Ethanol induced phosphorylation of ErbB2 at Tyr1248, FAK at Tyr861, and cSrc at Try216. Ethanol promoted the interaction among ErbB2, FAK, and cSrc, and the formation of a focal complex. AG825, a selective ErbB2 inhibitor, attenuated the ethanol-induced phosphorylation of ErbB2 and its association with FAK. Furthermore, AG825 blocked ethanol-promoted cell / fibronectin adhesion as well as the expression of focal adhesions. Conclusions Our results suggest that ethanol enhances the adhesion of breast cancer cells to fibronectin in an ErbB2-dependent manner, and the FAK pathway plays an important role in ethanol-induced formation of a focal complex. PMID:20201928

  13. Recipient-derived EDA fibronectin promotes cardiac allograft fibrosis.

    PubMed

    Booth, Adam J; Wood, Sherri C; Cornett, Ashley M; Dreffs, Alyssa A; Lu, Guanyi; Muro, Andrés F; White, Eric S; Bishop, D Keith

    2012-03-01

    Advances in donor matching and immunosuppressive therapies have decreased the prevalence of acute rejection of cardiac grafts; however, chronic rejection remains a significant obstacle for long-term allograft survival. While initiating elements of anti-allograft immune responses have been identified, the linkage between these factors and the ultimate development of cardiac fibrosis is not well understood. Tissue fibrosis resembles an exaggerated wound healing response, in which extracellular matrix (ECM) molecules are central. One such ECM molecule is an alternatively spliced isoform of the ubiquitous glycoprotein fibronectin (FN), termed extra domain A-containing cellular fibronectin (EDA cFN). EDA cFN is instrumental in fibrogenesis; thus, we hypothesized that it might also regulate fibrotic remodelling associated with chronic rejection. We compared the development of acute and chronic cardiac allograft rejection in EDA cFN-deficient (EDA(-/-)) and wild-type (WT) mice. While EDA(-/-) mice developed acute cardiac rejection in a manner indistinguishable from WT controls, cardiac allografts in EDA(-/-) mice were protected from fibrosis associated with chronic rejection. Decreased fibrosis was not associated with differences in cardiomyocyte hypertrophy or intra-graft expression of pro-fibrotic mediators. Further, we examined expression of EDA cFN and total FN by whole splenocytes under conditions promoting various T-helper lineages. Conditions supporting regulatory T-cell (Treg) development were characterized by greatest production of total FN and EDA cFN, though EDA cFN to total FN ratios were highest in Th1 cultures. These findings indicate that recipient-derived EDA cFN is dispensable for acute allograft rejection responses but that it promotes the development of fibrosis associated with chronic rejection. Further, conditions favouring the development of regulatory T cells, widely considered graft-protective, may drive production of ECM molecules which enhance

  14. Material-driven fibronectin assembly for high-efficiency presentation of growth factors

    PubMed Central

    Llopis-Hernández, Virginia; Cantini, Marco; González-García, Cristina; Cheng, Zhe A.; Yang, Jingli; Tsimbouri, Penelope M; García, Andrés J.; Dalby, Matthew J.; Salmerón-Sánchez, Manuel

    2016-01-01

    Growth factors (GFs) are powerful signaling molecules with the potential to drive regenerative strategies, including bone repair and vascularization. However, GFs are typically delivered in soluble format at supraphysiological doses because of rapid clearance and limited therapeutic impact. These high doses have serious side effects and are expensive. Although it is well established that GF interactions with extracellular matrix proteins such as fibronectin control GF presentation and activity, a translation-ready approach to unlocking GF potential has not been realized. We demonstrate a simple, robust, and controlled material-based approach to enhance the activity of GFs during tissue healing. The underlying mechanism is based on spontaneous fibrillar organization of fibronectin driven by adsorption onto the polymer poly(ethyl acrylate). Fibrillar fibronectin on this polymer, but not a globular conformation obtained on control polymers, promotes synergistic presentation of integrin-binding sites and bound bone morphogenetic protein 2 (BMP-2), which enhances mesenchymal stem cell osteogenesis in vitro and drives full regeneration of a nonhealing bone defect in vivo at low GF concentrations. This simple and translatable technology could unlock the full regenerative potential of GF therapies while improving safety and cost-effectiveness. PMID:27574702

  15. Material-driven fibronectin assembly for high-efficiency presentation of growth factors.

    PubMed

    Llopis-Hernández, Virginia; Cantini, Marco; González-García, Cristina; Cheng, Zhe A; Yang, Jingli; Tsimbouri, Penelope M; García, Andrés J; Dalby, Matthew J; Salmerón-Sánchez, Manuel

    2016-08-01

    Growth factors (GFs) are powerful signaling molecules with the potential to drive regenerative strategies, including bone repair and vascularization. However, GFs are typically delivered in soluble format at supraphysiological doses because of rapid clearance and limited therapeutic impact. These high doses have serious side effects and are expensive. Although it is well established that GF interactions with extracellular matrix proteins such as fibronectin control GF presentation and activity, a translation-ready approach to unlocking GF potential has not been realized. We demonstrate a simple, robust, and controlled material-based approach to enhance the activity of GFs during tissue healing. The underlying mechanism is based on spontaneous fibrillar organization of fibronectin driven by adsorption onto the polymer poly(ethyl acrylate). Fibrillar fibronectin on this polymer, but not a globular conformation obtained on control polymers, promotes synergistic presentation of integrin-binding sites and bound bone morphogenetic protein 2 (BMP-2), which enhances mesenchymal stem cell osteogenesis in vitro and drives full regeneration of a nonhealing bone defect in vivo at low GF concentrations. This simple and translatable technology could unlock the full regenerative potential of GF therapies while improving safety and cost-effectiveness. PMID:27574702

  16. Small GTPase Rab21 Mediates Fibronectin Induced Actin Reorganization in Entamoeba histolytica: Implications in Pathogen Invasion

    PubMed Central

    Emmanuel, Merlyn; Nakano, Yumiko Saito; Nozaki, Tomoyoshi; Datta, Sunando

    2015-01-01

    The protozoan parasite Entamoeba histolytica causes a wide spectrum of intestinal infections. In severe cases, the trophozoites can breach the mucosal barrier, invade the intestinal epithelium and travel via the portal circulation to the liver, where they cause hepatic abscesses, which can prove fatal if left untreated. The host Extra Cellular Matrix (ECM) plays a crucial role in amoebic invasion by triggering an array of cellular responses in the parasite, including induction of actin rich adhesion structures. Similar actin rich protrusive structures, known as ‘invadosomes’, promote chemotactic migration of the metastatic cancer cells and non-transformed cells by remodeling the ECM. Recent studies showed a central role for Rab GTPases, the master regulators of vesicular trafficking, in biogenesis of invadosomes. Here, we showed that fibronectin, a major host ECM component induced actin remodeling in the parasite in a Rab21 dependent manner. The focalized actin structures formed were reminiscent of the mammalian invadosomes. By using various approaches, such as immunofluorescence confocal microscopy and scanning electron microscopy, along with in vitro invasion assay and matrix degradation assay, we show that the fibronectin induced formation of amoebic actin dots depend on the nucleotide status of the GTPase. The ECM components, fibronectin and collagen type I, displayed differential control over the formation of actin dots, with fibronectin positively and collagen type I negatively modulating it. The cell surface adhesion molecule Gal/GalNAc complex was also found to impose additional regulation on this process, which might have implication in collagen type I mediated suppression of actin dots. PMID:25730114

  17. Bonds between fibronectin and fibronectin-binding proteins on Staphylococcus aureus and Lactococcus lactis.

    PubMed

    Buck, Andrew W; Fowler, Vance G; Yongsunthon, Ruchirej; Liu, Jie; DiBartola, Alex C; Que, Yok-Ai; Moreillon, Philippe; Lower, Steven K

    2010-07-01

    Bacterial cell-wall-associated fibronectin binding proteins A and B (FnBPA and FnBPB) form bonds with host fibronectin. This binding reaction is often the initial step in prosthetic device infections. Atomic force microscopy was used to evaluate binding interactions between a fibronectin-coated probe and laboratory-derived Staphylococcus aureus that are (i) defective in both FnBPA and FnBPB (fnbA fnbB double mutant, DU5883), (ii) capable of expressing only FnBPA (fnbA fnbB double mutant complemented with pFNBA4), or (iii) capable of expressing only FnBPB (fnbA fnbB double mutant complemented with pFNBB4). These experiments were repeated using Lactococcus lactis constructs expressing fnbA and fnbB genes from S. aureus. A distinct force signature was observed for those bacteria that expressed FnBPA or FnBPB. Analysis of this force signature with the biomechanical wormlike chain model suggests that parallel bonds form between fibronectin and FnBPs on a bacterium. The strength and covalence of bonds were evaluated via nonlinear regression of force profiles. Binding events were more frequent (p < 0.01) for S. aureus expressing FnBPA or FnBPB than for the S. aureus double mutant. The binding force, frequency, and profile were similar between the FnBPA and FnBPB expressing strains of S. aureus. The absence of both FnBPs from the surface of S. aureus removed its ability to form a detectable bond with fibronectin. By contrast, ectopic expression of FnBPA or FnBPB on the surface of L. lactis conferred fibronectin binding characteristics similar to those of S. aureus. These measurements demonstrate that fibronectin-binding adhesins FnBPA and FnBPB are necessary and sufficient for the binding of S. aureus to prosthetic devices that are coated with host fibronectin. PMID:20218549

  18. Fibronectin Deposition Participates in Extracellular Matrix Assembly and Vascular Morphogenesis

    PubMed Central

    Hielscher, Abigail; Ellis, Kim; Qiu, Connie; Porterfield, Josh; Gerecht, Sharon

    2016-01-01

    The extracellular matrix (ECM) has been demonstrated to facilitate angiogenesis. In particular, fibronectin has been documented to activate endothelial cells, resulting in their transition from a quiescent state to an active state in which the cells exhibit enhanced migration and proliferation. The goal of this study is to examine the role of polymerized fibronectin during vascular tubulogenesis using a 3 dimensional (3D) cell-derived de-cellularized matrix. A fibronectin-rich 3D de-cellularized ECM was used as a scaffold to study vascular morphogenesis of endothelial cells (ECs). Confocal analyses of several matrix proteins reveal high intra- and extra-cellular deposition of fibronectin in formed vascular structures. Using a small peptide inhibitor of fibronectin polymerization, we demonstrate that inhibition of fibronectin fibrillogenesis in ECs cultured atop de-cellularized ECM resulted in decreased vascular morphogenesis. Further, immunofluorescence and ultrastructural analyses reveal decreased expression of stromal matrix proteins in the absence of polymerized fibronectin with high co-localization of matrix proteins found in association with polymerized fibronectin. Evaluating vascular kinetics, live cell imaging showed that migration, migration velocity, and mean square displacement, are disrupted in structures grown in the absence of polymerized fibronectin. Additionally, vascular organization failed to occur in the absence of a polymerized fibronectin matrix. Consistent with these observations, we tested vascular morphogenesis following the disruption of EC adhesion to polymerized fibronectin, demonstrating that block of integrins α5β1 and αvβ3, abrogated vascular morphogenesis. Overall, fibronectin deposition in a 3D cell-derived de-cellularized ECM appears to be imperative for matrix assembly and vascular morphogenesis. PMID:26811931

  19. Sorption of fibronectin to human root surfaces in vitro

    SciTech Connect

    Mendieta, C.; Caravana, C.; Fine, D.H. )

    1990-05-01

    The purpose of this study was to determine the conditions that favor the sorption and retention of human plasma fibronectin to cementum. Rectangular root segments prepared from teeth extracted for orthodontic reasons were mounted on a capillary pipette and immersed in solutions of {sup 125}I fibronectin for assay of cementum sorption under various conditions. Kinetic studies showed sorption to be rapid, with 77% of the maximum fibronectin sorption occurring within 1 minute. Fibronectin sorption was reduced when added in conjunction with serum and was inhibited by monovalent ions (such as sodium), but enhanced in the presence of divalent cations (such as calcium). Exposure of cementum to serum partially blocked subsequent sorption of fibronectin, while cementum bound fibronectin was eluted by subsequent exposure to serum. Treatment of cementum with citric acid pH 1.1 (4 minutes) followed by 5% sodium hypochlorite (5 minutes) caused a significant increase in fibronectin sorption with maximum retention upon subsequent exposure to serum (P less than 0.05). Fibronectin sorption to cementum was: rapid, electrostatic in nature, competitive, reversible, Ca+(+)-facilitated, and maximized by prior treatment of the root with citric acid and sodium hypochlorite. It is concluded that sorption of fibronectin to cementum can be achieved for clinical gain; however, conditions of application can significantly influence both accumulation and subsequent release of root sorbed material.

  20. Periostin promotes secretion of fibronectin from the endoplasmic reticulum.

    PubMed

    Kii, Isao; Nishiyama, Takashi; Kudo, Akira

    2016-02-19

    Extracellular matrix (ECM) proteins are synthesized in the endoplasmic reticulum (ER), transported to the extracellular milieu through the secretory pathway, and assembled into an extracellular architecture. A previous study of ours showed that periostin, a secretory protein, interacts with fibronectin and is involved in ECM remodeling. Here we show that periostin played a role in fibronectin secretion from the ER. Co-immunoprecipitation and in situ proximity ligation assays revealed an interaction between periostin and fibronectin in the ER. Although accumulation of fibronectin was detected in the ER of fibroblastic C3H10T1/2 cells, forced expression of periostin in those cells decreased the accumulation of fibronectin in the ER, suggesting that periostin promoted the secretion of fibronectin. A substitution mutant of tryptophan at the position 65 to alanine in the EMI domain of periostin, which caused periostin to lose its ability to interact with fibronectin, did not decrease the accumulation. Furthermore, targeted disruption of periostin in mice caused the non-fibrillar and ectopic deposition of fibronectin in the periodontal ligament. Thus, these results demonstrate a subcellular role of periostin in promotion of fibronectin secretion from the ER. PMID:26820539

  1. Plasma fibronectin deficiency during chemotherapy of acute myeloid leukaemia.

    PubMed

    Brodin, B; Liedén, G; Malm, C; Vikrot, O

    1983-03-01

    Plasma fibronectin was determined using a laser nephelometric method in 10 patients with acute myeloid leukaemia undergoing chemotherapy. There was a continuous fall during the first 3 weeks to about 50% of the normal level. The decrease of fibronectin may contribute to the lowered resistance against infection characteristic of these patients. PMID:6574587

  2. Molecular architecture of native fibronectin fibrils.

    PubMed

    Früh, Susanna Maria; Schoen, Ingmar; Ries, Jonas; Vogel, Viola

    2015-01-01

    Fibronectin fibrils within the extracellular matrix play central roles in physiological and pathological processes, yet many structural details about their hierarchical and molecular assembly remain unknown. Here we combine site-specific protein labelling with single-molecule localization by stepwise photobleaching or direct stochastic optical reconstruction microscopy (dSTORM), and determine the relative positions of various labelled sites within native matrix fibrils. Single end-labelled fibronectin molecules in fibrils display an average end-to-end distance of ∼133 nm. Sampling of site-specific antibody epitopes along the thinnest fibrils (protofibrils) shows periodic punctate label patterns with ∼95 nm repeats and alternating N- and C-terminal regions. These measurements suggest an antiparallel 30-40 nm overlap between N-termini, suggesting that the first five type I modules bind type III modules of the adjacent molecule. Thicker fibres show random bundling of protofibrils without a well-defined line-up. This super-resolution microscopy approach can be applied to other fibrillar protein assemblies of unknown structure. PMID:26041410

  3. Molecular architecture of native fibronectin fibrils

    NASA Astrophysics Data System (ADS)

    Früh, Susanna Maria; Schoen, Ingmar; Ries, Jonas; Vogel, Viola

    2015-06-01

    Fibronectin fibrils within the extracellular matrix play central roles in physiological and pathological processes, yet many structural details about their hierarchical and molecular assembly remain unknown. Here we combine site-specific protein labelling with single-molecule localization by stepwise photobleaching or direct stochastic optical reconstruction microscopy (dSTORM), and determine the relative positions of various labelled sites within native matrix fibrils. Single end-labelled fibronectin molecules in fibrils display an average end-to-end distance of ~133 nm. Sampling of site-specific antibody epitopes along the thinnest fibrils (protofibrils) shows periodic punctate label patterns with ~95 nm repeats and alternating N- and C-terminal regions. These measurements suggest an antiparallel 30-40 nm overlap between N-termini, suggesting that the first five type I modules bind type III modules of the adjacent molecule. Thicker fibres show random bundling of protofibrils without a well-defined line-up. This super-resolution microscopy approach can be applied to other fibrillar protein assemblies of unknown structure.

  4. Molecular architecture of native fibronectin fibrils

    PubMed Central

    Früh, Susanna Maria; Schoen, Ingmar; Ries, Jonas; Vogel, Viola

    2015-01-01

    Fibronectin fibrils within the extracellular matrix play central roles in physiological and pathological processes, yet many structural details about their hierarchical and molecular assembly remain unknown. Here we combine site-specific protein labelling with single-molecule localization by stepwise photobleaching or direct stochastic optical reconstruction microscopy (dSTORM), and determine the relative positions of various labelled sites within native matrix fibrils. Single end-labelled fibronectin molecules in fibrils display an average end-to-end distance of ∼133 nm. Sampling of site-specific antibody epitopes along the thinnest fibrils (protofibrils) shows periodic punctate label patterns with ∼95 nm repeats and alternating N- and C-terminal regions. These measurements suggest an antiparallel 30–40 nm overlap between N-termini, suggesting that the first five type I modules bind type III modules of the adjacent molecule. Thicker fibres show random bundling of protofibrils without a well-defined line-up. This super-resolution microscopy approach can be applied to other fibrillar protein assemblies of unknown structure. PMID:26041410

  5. Fibronectin as a Prognostic Indicator in Portal Hypertension

    PubMed Central

    Maharaj, D. P.; Garden, O. J.; Carter, D. C.

    1992-01-01

    Plasma fibronectin levels were measured in 33 patients with portal hypertension and c6mpared with modified Child’s grading and a previously described prognostic index. Outcome at one year from blood sampling was recorded. Mean plasma fibronectin level was 304.1 mg/ml (sem 24.3) and significantly lower levels were found in patients who had had a variceal bleed within the previous seven days. Plasma fibronectin levels tended to be lower in patients with poor liver function as assessed by modified Child’s grading but this did not achieve statistical significance. Plasma fibronectin alone was not an accurate predictor of one year survival in these patients but only one of seven patients who had a plasma fibronectin level below 300mg/l in association with a poor prognostic index survived for one year. PMID:1390363

  6. Fibroblast migration on fibronectin requires three distinct functional domains.

    PubMed

    Clark, Richard A F; An, Jian-Qiang; Greiling, Doris; Khan, Azim; Schwarzbauer, Jean E

    2003-10-01

    Mesenchymal cell movement is normally constrained; however, fibronectin can provide a pathway for stromal cell migration during embryogenesis, morphogenesis, and wound healing. Cells can adhere to fibronectin via integrin and nonintegrin receptors, which bind multiple unique peptide sequences. Synthetic peptides and recombinant proteins were used to delineate the functional domains needed for human fibroblast migration over fibronectin. The 9th and 10th fibronectin type III repeats, which contain RGD and PHSRN synergy cell attachment sequences, support almost maximal fibroblast attachment, but not migration of primary dermal fibroblasts. Specific sequences within the heparin domain and the IIICS region are also required for migration. These findings predict and additional data confirm the necessity for the cooperation of multiple integrin and nonintegrin receptors for fibroblast migration on fibronectin. Such stringency of migration most likely imposes an immense constraint on normal mesenchymal cell mobility in unperturbed tissue. Loss of such restraint may be critical for the migration cancer cells through the extracellular matrix. PMID:14632184

  7. Characterization of the fibronectin-attachment protein of Mycobacterium avium reveals a fibronectin-binding motif conserved among mycobacteria.

    PubMed

    Schorey, J S; Holsti, M A; Ratliff, T L; Allen, P M; Brown, E J

    1996-07-01

    Mycobacterium avium is an intracellular pathogen and a major opportunistic infectious agent observed in patients with acquired immune deficiency syndrome (AIDS). Evidence suggests that the initial portal of infection by M. avium is often the gastrointestinal tract. However, the mechanism by which the M. avium crosses the epithelial barrier is unclear. A possible mechanism is suggested by the ability of M. avium to bind fibronectin, an extracellular matrix protein that is a virulence factor for several extracellular pathogenic bacteria which bind to mucosal surfaces. To further characterize fibronectin binding by M. avium, we have cloned the M. avium fibronectin-attachment protein (FAP). The M. avium FAP (FAP-A) has an unusually large number of Pro and Ala residues (40% overall) and is 50% identical to FAP of both Mycobacterium leprae and Mycobacterium tuberculosis. Using recombinant FAP-A and FAP-A peptides, we show that two non-continuous regions in FAP-A bind fibronectin. Peptides from these regions and homologous sequences from M. leprae FAP inhibit fibronectin binding by both M. avium and Mycobacterium bovis Bacillus Calmette-Guerin (BCG). These regions have no homology to eukaryotic fibronectin-binding proteins and are only distantly related to fibronectin-binding peptides of Gram-positive bacteria. Nevertheless, these fibronectin-binding regions are highly conserved among the mycobacterial FAPs, suggesting an essential function for this interaction in mycobacteria infection of their metazoan hosts. PMID:8858587

  8. Utilizing Fibronectin Integrin-Binding Specificity to Control Cellular Responses

    PubMed Central

    Bachman, Haylee; Nicosia, John; Dysart, Marilyn; Barker, Thomas H.

    2015-01-01

    Significance: Cells communicate with the extracellular matrix (ECM) protein fibronectin (Fn) through integrin receptors on the cell surface. Controlling integrin–Fn interactions offers a promising approach to directing cell behavior, such as adhesion, migration, and differentiation, as well as coordinated tissue behaviors such as morphogenesis and wound healing. Recent Advances: Several different groups have developed recombinant fragments of Fn that can control epithelial to mesenchymal transition, sequester growth factors, and promote bone and wound healing. It is thought that these physiological responses are, in part, due to specific integrin engagement. Furthermore, it has been postulated that the integrin-binding domain of Fn is a mechanically sensitive switch that drives binding of one integrin heterodimer over another. Critical Issues: Although computational simulations have predicted the mechano-switch hypothesis and recent evidence supports the existence of varying strain states of Fn in vivo, experimental evidence of the Fn integrin switch is still lacking. Future Directions: Evidence of the integrin mechano-switch will enable the development of new Fn-based peptides in tissue engineering and wound healing, as well as deepen our understanding of ECM pathologies, such as fibrosis. PMID:26244106

  9. Recipient–derived EDA fibronectin promotes cardiac allograft fibrosis

    PubMed Central

    Booth, Adam J; Wood, Sherri C; Cornett, Ashley M; Dreffs, Alyssa A; Lu, Guanyi; Muro, Andrés F; White, Eric S; Bishop, D Keith

    2014-01-01

    Advances in donor matching and immunosuppressive therapies have decreased the prevalence of acute rejection of cardiac grafts; however, chronic rejection remains a significant obstacle for long-term allograft survival. While initiating elements of anti-allograft immune responses have been identified, the linkage between these factors and the ultimate development of cardiac fibrosis is not well understood. Tissue fibrosis resembles an exaggerated wound healing response, in which extracellular matrix (ECM) molecules are central. One such ECM molecule is an alternatively spliced isoform of the ubiquitous glycoprotein fibronectin (FN), termed extra domain A-containing cellular fibronectin (EDA cFN). EDA cFN is instrumental in fibrogenesis; thus, we hypothesized that it might also regulate fibrotic remodelling associated with chronic rejection. We compared the development of acute and chronic cardiac allograft rejection in EDA cFN-deficient (EDA−/−) and wild-type (WT) mice. While EDA−/− mice developed acute cardiac rejection in a manner indistinguishable from WT controls, cardiac allografts in EDA−/− mice were protected from fibrosis associated with chronic rejection. Decreased fibrosis was not associated with differences in cardiomyocyte hypertrophy or intra-graft expression of pro-fibrotic mediators. Further, we examined expression of EDA cFN and total FN by whole splenocytes under conditions promoting various T-helper lineages. Conditions supporting regulatory T-cell (Treg) development were characterized by greatest production of total FN and EDA cFN, though EDA cFN to total FN ratios were highest in Th1 cultures. These findings indicate that recipient-derived EDA cFN is dispensable for acute allograft rejection responses but that it promotes the development of fibrosis associated with chronic rejection. Further, conditions favouring the development of regulatory T cells, widely considered graft-protective, may drive production of ECM molecules which

  10. Differential deposition of fibronectin by asthmatic bronchial epithelial cells.

    PubMed

    Ge, Qi; Zeng, Qingxiang; Tjin, Gavin; Lau, Edmund; Black, Judith L; Oliver, Brian G G; Burgess, Janette K

    2015-11-15

    Altered ECM protein deposition is a feature in asthmatic airways. Fibronectin (Fn), an ECM protein produced by human bronchial epithelial cells (HBECs), is increased in asthmatic airways. This study investigated the regulation of Fn production in asthmatic or nonasthmatic HBECs and whether Fn modulated HBEC proliferation and inflammatory mediator secretion. The signaling pathways underlying transforming growth factor (TGF)-β1-regulated Fn production were examined using specific inhibitors for ERK, JNK, p38 MAPK, phosphatidylinositol 3 kinase, and activin-like kinase 5 (ALK5). Asthmatic HBECs deposited higher levels of Fn in the ECM than nonasthmatic cells under basal conditions, whereas cells from the two groups had similar levels of Fn mRNA and soluble Fn. TGF-β1 increased mRNA levels and ECM and soluble forms of Fn but decreased cell proliferation in both cells. The rate of increase in Fn mRNA was higher in nonasthmatic cells. However, the excessive amounts of ECM Fn deposited by asthmatic cells after TGF-β1 stimulation persisted compared with nonasthmatic cells. Inhibition of ALK5 completely prevented TGF-β1-induced Fn deposition. Importantly, ECM Fn increased HBEC proliferation and IL-6 release, decreased PGE2 secretion, but had no effect on VEGF release. Soluble Fn had no effect on cell proliferation and inflammatory mediator release. Asthmatic HBECs are intrinsically primed to produce more ECM Fn, which when deposited into the ECM, is capable of driving remodeling and inflammation. The increased airway Fn may be one of the key driving factors in the persistence of asthma and represents a novel, therapeutic target. PMID:26342086

  11. Cadherin-11 localizes to focal adhesions and promotes cell–substrate adhesion

    PubMed Central

    Langhe, Rahul P.; Gudzenko, Tetyana; Bachmann, Michael; Becker, Sarah F.; Gonnermann, Carina; Winter, Claudia; Abbruzzese, Genevieve; Alfandari, Dominique; Kratzer, Marie-Claire; Franz, Clemens M.; Kashef, Jubin

    2016-01-01

    Cadherin receptors have a well-established role in cell–cell adhesion, cell polarization and differentiation. However, some cadherins also promote cell and tissue movement during embryonic development and tumour progression. In particular, cadherin-11 is upregulated during tumour and inflammatory cell invasion, but the mechanisms underlying cadherin-11 stimulated cell migration are still incompletely understood. Here, we show that cadherin-11 localizes to focal adhesions and promotes adhesion to fibronectin in Xenopus neural crest, a highly migratory embryonic cell population. Transfected cadherin-11 also localizes to focal adhesions in different mammalian cell lines, while endogenous cadherin-11 shows focal adhesion localization in primary human fibroblasts. In focal adhesions, cadherin-11 co-localizes with β1-integrin and paxillin and physically interacts with the fibronectin-binding proteoglycan syndecan-4. Adhesion to fibronectin mediated by cadherin-11/syndecan-4 complexes requires both the extracellular domain of syndecan-4, and the transmembrane and cytoplasmic domains of cadherin-11. These results reveal an unexpected role of a classical cadherin in cell–matrix adhesion during cell migration. PMID:26952325

  12. Guidance of myogenic cell migration by oriented deposits of fibronectin.

    PubMed

    Turner, D C; Lawton, J; Dollenmeier, P; Ehrismann, R; Chiquet, M

    1983-02-01

    Fibronectin mediates myoblast-substratum attachment; one region of the molecule binds directly to the cell surface, while others bind to collagen, glycosaminoglycans, and other fibronectin molecules. There is evidence to suggest that fibronectin-containing extracellular matrices guide cell migration in vivo. We describe a method for producing regular deposits of fibronectin in vitro that can serve as a model system for studying cell-substrate interactions, cell orientation, and contact guidance. The novel culture substrate is prepared by allowing an aqueous solution of fibronectin and urea to dry in a culture dish and then washing away the urea crystals. Myogenic cells in vitro adhere to, align with, and migrate along, parallel streaks of fibronectin. This leads to the formation of myotubes that are long and thin, with little branching. Myogenic clones are highly elongated in the direction of the deposits, in contrast with the roughly circular clones seen in conventional cultures. Fibroblasts and limb bud mesenchymal cells align with fibronectin deposits, assuming a bipolar shape. PMID:6825944

  13. Propolis Modulates Fibronectin Expression in the Matrix of Thermal Injury

    PubMed Central

    Komosinska-Vassev, Katarzyna; Wisowski, Grzegorz; Mencner, Lukasz; Stojko, Jerzy; Kozma, Ewa M.

    2014-01-01

    The aim of the study was to assess the propolis effect on fibronectin metabolism in the course of burn wounds healing process. A model of burn wound healing of pig skin was applied. The amount of the released glycoprotein was assessed by a surface plasmon resonance. The profile of extracted fibronectin components was also assessed by an electrophoresis in polyacrylamide gel, with a subsequent immunodetection by Western Blotting. Propolis burn treatment decreased the release of fibronectin components from healing wounds in relation to damages treated with silver sulfadiazine. The main reason of decreased extraction of fibronectin components from wounds treated with propolis was a substantial decrease of degradation product release of the mentioned glycoprotein, which was observed particularly from the 3rd to 5th day of the repair. Wounds treatment with propolis demonstrated, especially in relation to damages treated with silver sulfadiazine, the decreased release of synthesized fibronectin molecules. The obtained results suggest that propolis modifies fibronectin metabolism in the course of wound healing process. The influence of propolis is reflected in prevention of fibronectin biosynthesis as well as its degradation in the wound area. The above-mentioned metabolic changes may decrease the risk of complications in the repair wounds process. PMID:24738072

  14. Propolis modulates fibronectin expression in the matrix of thermal injury.

    PubMed

    Olczyk, Pawel; Komosinska-Vassev, Katarzyna; Wisowski, Grzegorz; Mencner, Lukasz; Stojko, Jerzy; Kozma, Ewa M

    2014-01-01

    The aim of the study was to assess the propolis effect on fibronectin metabolism in the course of burn wounds healing process. A model of burn wound healing of pig skin was applied. The amount of the released glycoprotein was assessed by a surface plasmon resonance. The profile of extracted fibronectin components was also assessed by an electrophoresis in polyacrylamide gel, with a subsequent immunodetection by Western Blotting. Propolis burn treatment decreased the release of fibronectin components from healing wounds in relation to damages treated with silver sulfadiazine. The main reason of decreased extraction of fibronectin components from wounds treated with propolis was a substantial decrease of degradation product release of the mentioned glycoprotein, which was observed particularly from the 3rd to 5th day of the repair. Wounds treatment with propolis demonstrated, especially in relation to damages treated with silver sulfadiazine, the decreased release of synthesized fibronectin molecules. The obtained results suggest that propolis modifies fibronectin metabolism in the course of wound healing process. The influence of propolis is reflected in prevention of fibronectin biosynthesis as well as its degradation in the wound area. The above-mentioned metabolic changes may decrease the risk of complications in the repair wounds process. PMID:24738072

  15. Fibronectin maintains the balance between hemostasis and thrombosis.

    PubMed

    Wang, Yiming; Ni, Heyu

    2016-09-01

    Fibronectin is a dimeric protein widely distributed in solid tissues and blood. This major extracellular matrix protein is indispensable for embryogenesis and plays crucial roles in many physiological and pathological processes. Fibronectin pre-mRNA undergoes alternative splicing to generate over 20 splicing variants, which are categorized as either plasma fibronectin (pFn) or cellular fibronectin (cFn). All fibronectin variants contain integrin binding motifs, as well as N-terminus collagen and fibrin binding motifs. With motifs that can be recognized by platelet integrins and coagulation factors, fibronectin, especially pFn, has long been suspected to be involved in hemostasis and thrombosis, but the exact function of fibronectin in these processes is controversial. The advances made using intravital microscopy models and fibronectin deficient and mutant mice have greatly facilitated the direct investigation of fibronectin function in vivo. Recent studies revealed that pFn is a vital hemostatic factor that is especially crucial for hemostasis in both genetic and anticoagulant-induced deficiencies of fibrin formation. pFn may also be an important self-limiting regulator to prevent hemorrhage as well as excessive thrombus formation and vessel occlusion. In addition to pFn, cFn is found to be prothrombotic and may contribute to thrombotic complications in various diseases. Further investigations of the role of pFn and cFn in thrombotic and hemorrhagic diseases may provide insights into development of novel therapeutic strategies (e.g., pFn transfusion) for the maintenance of the fine balance between hemostasis and thrombosis. PMID:27098513

  16. Adhesion of fibroblasts to fibronectin stimulates both serine and tyrosine phosphorylation of paxillin.

    PubMed Central

    Bellis, S L; Perrotta, J A; Curtis, M S; Turner, C E

    1997-01-01

    Tyrosine phosphorylation of paxillin by the focal adhesion kinase (FAK) has been implicated as a signal transduction mechanism associated with cell adhesion and cytoskeletal reorganization. The potential role of serine phosphorylation of paxillin in these events has not been well characterized. In this study we have examined the phosphorylation profile of paxillin both in vitro and in vivo. By using glutathione S-transferase-paxillin fusion proteins in precipitation-kinase assays in vitro we observed that a fusion protein spanning amino acid residues 54-313 of paxillin, and containing a FAK-binding site, precipitated substantial serine kinase activity as well as FAK activity from a smooth-muscle lysate. Together these kinases phosphorylated paxillin on tyrosine residue 118, a site that has been identified previously as a target for FAK phosphorylation, and on serine residues 188 and/or 190. The binding site for the serine kinase, the identity of which is currently unknown, was further mapped to residues 168-191 of paxillin. To assess the physiological relevance of these sites phosphorylated in vitro, the profile of paxillin phosphorylation in vivo stimulated by seeding fibroblasts on fibronectin was characterized. As expected, plating cells on fibronectin enhanced the tyrosine phosphorylation of paxillin. However, 96% of the phosphorylation of paxillin occurred on serine residues. Comparison by two-dimensional phosphopeptide analyses indicated that the major sites of tyrosine and serine phosphorylation detected in the assays in vitro co-migrate with phosphopeptides derived from paxillin phosphorylated in vivo in response to plating cells on fibronectin. These findings support a role for both tyrosine and serine kinases in the signal transduction pathway linking integrin activation to paxillin phosphorylation. PMID:9230116

  17. Plasma fibronectin concentrations in dogs with disseminated intravascular coagulation.

    PubMed

    Feldman, B F; Thomson, D B; O'Neill, S

    1985-05-01

    Plasma fibronectin concentrations were significantly (P less than 0.001) below the reference range in dogs with disseminated intravascular coagulation (DIC) secondary to nonlymphomatous neoplasia, acute necrotizing pancreatitis, sepsis, chronic active hepatitis, and heat stroke. There was no statistical evidence of a group effect. Decrease in fibronectin concentration was associated with severe DIC, although no attempt was made to correlate fibronectin concentration with prognosis. These findings parallel those reported for severely ill human beings with diseases associated with DIC. They exemplify the potential of spontaneous diseases in animals as models for the study of human disease. PMID:4003893

  18. A fibronectin mimetic motif improves integrin mediated cell biding to recombinant spider silk matrices.

    PubMed

    Widhe, Mona; Shalaly, Nancy Dekki; Hedhammar, My

    2016-01-01

    The cell binding motif RGD is the most widely used peptide to improve cell binding properties of various biomaterials, including recombinant spider silk. In this paper we use genetic engineering to further enhance the cell supportive capacity of spider silk by presenting the RGD motif as a turn loop, similar to the one found in fibronectin (FN), but in the silk stabilized by cysteines, and therefore denoted FNCC. Human primary cells cultured on FNCC-silk showed increased attachment, spreading, stress fiber formation and focal adhesions, not only compared to RGD-silk, but also to silk fused with linear controls of the RGD containing motif from fibronectin. Cell binding to FNCC-silk was shown to involve the α5β1 integrin, and to support proliferation and migration of keratinocytes. The FNCC-silk protein allowed efficient assembly, and could even be transformed into free standing films, on which keratinocytes could readily form a monolayer culture. The results hold promise for future applications within tissue engineering. PMID:26461118

  19. Small Molecules Antagonise the MIA-Fibronectin Interaction in Malignant Melanoma

    PubMed Central

    Yip, King Tuo; Zhong, Xue Yin; Seibel, Nadia; Pütz, Stefanie; Autzen, Jasmin; Gasper, Raphael; Hofmann, Eckhard; Scherkenbeck, Jürgen; Stoll, Raphael

    2016-01-01

    Melanoma inhibitory activity (MIA), an extracellular protein highly expressed by malignant melanoma cells, plays an important functional role in melanoma development, progression, and metastasis. After its secretion, MIA directly interacts with extracellular matrix proteins, such as fibronectin (FN). By this mechanism, MIA actively facilitates focal cell detachment from surrounding structures and strongly promotes tumour cell invasion and migration. Hence, the molecular understanding of MIA’s function provides a promising target for the development of new strategies in malignant melanoma therapy. Here, we describe for the first time the discovery of small molecules that are able to disrupt the MIA-FN complex by selectively binding to a new druggable pocket, which we could identify on MIA by structural analysis and fragment-based screening. Our findings may inspire novel drug discovery efforts aiming at a therapeutically effective treatment of melanoma by targeting MIA. PMID:27151361

  20. Small Molecules Antagonise the MIA-Fibronectin Interaction in Malignant Melanoma.

    PubMed

    Yip, King Tuo; Zhong, Xue Yin; Seibel, Nadia; Pütz, Stefanie; Autzen, Jasmin; Gasper, Raphael; Hofmann, Eckhard; Scherkenbeck, Jürgen; Stoll, Raphael

    2016-01-01

    Melanoma inhibitory activity (MIA), an extracellular protein highly expressed by malignant melanoma cells, plays an important functional role in melanoma development, progression, and metastasis. After its secretion, MIA directly interacts with extracellular matrix proteins, such as fibronectin (FN). By this mechanism, MIA actively facilitates focal cell detachment from surrounding structures and strongly promotes tumour cell invasion and migration. Hence, the molecular understanding of MIA's function provides a promising target for the development of new strategies in malignant melanoma therapy. Here, we describe for the first time the discovery of small molecules that are able to disrupt the MIA-FN complex by selectively binding to a new druggable pocket, which we could identify on MIA by structural analysis and fragment-based screening. Our findings may inspire novel drug discovery efforts aiming at a therapeutically effective treatment of melanoma by targeting MIA. PMID:27151361

  1. Porins of Pseudomonas fluorescens MFO as fibronectin-binding proteins.

    PubMed

    Rebière-Huët, J; Guérillon, J; Pimenta, A L; Di Martino, P; Orange, N; Hulen, C

    2002-09-24

    Bacterial adherence is a complex phenomenon involving specific interactions between receptors, including matricial fibronectin, and bacterial ligands. We show here that fibronectin and outer membrane proteins of Pseudomonas fluorescens were able to inhibit adherence of P. fluorescens to fibronectin-coated wells. We identified at least six fibronectin-binding proteins with molecular masses of 70, 55, 44, 37, 32 and 28 kDa. The presence of native (32 kDa) and heat-modified forms (37 kDa) of OprF was revealed by immuno-analysis and the 44-kDa band was composed of three proteins, their N-terminal sequences showing homologies with Pseudomonas aeruginosa porins (OprD, OprE1 and OprE3). PMID:12393211

  2. Beamlet focal plane diagnostic

    SciTech Connect

    Caird, J.A.; Nielsen, N.D.; Patton, H.G.; Seppala, L.G.; Thompson, C.E.; Wegner, P.J.

    1996-12-01

    This paper describes the major optical and mechanical design features of the Beamlet Focal Plane Diagnostic system as well as measurements of the system performance, and typical data obtained to date. We also discuss the NIF requirements on the focal spot that we are interested in measuring, and some of our plans for future work using this system.

  3. Fibronectin matrix assembly is essential for cell condensation during chondrogenesis

    PubMed Central

    Singh, Purva; Schwarzbauer, Jean E.

    2014-01-01

    ABSTRACT Mesenchymal cell condensation is the initiating event in endochondral bone formation. Cell condensation is followed by differentiation into chondrocytes, which is accompanied by induction of chondrogenic gene expression. Gene mutations involved in chondrogenesis cause chondrodysplasias and other skeletal defects. Using mesenchymal stem cells (MSCs) in an in vitro chondrogenesis assay, we found that knockdown of the diastrophic dysplasia (DTD) sulfate transporter (DTDST, also known as SLC26A2), which is required for normal cartilage development, blocked cell condensation and caused a significant reduction in fibronectin matrix. Knockdown of fibronectin with small interfering RNAs (siRNAs) also blocked condensation. Fibrillar fibronectin matrix was detected prior to cell condensation, and its levels increased during and after condensation. Inhibition of fibronectin matrix assembly by use of the functional upstream domain (FUD) of adhesin F1 from Streptococcus pyogenes prevented cell condensation by MSCs and also by the chondrogenic cell line ATDC5. Our data show that cell condensation and induction of chondrogenesis depend on fibronectin matrix assembly and DTDST, and indicate that this transporter is required earlier in chondrogenesis than previously appreciated. They also raise the possibility that certain of the skeletal defects in DTD patients might derive from the link between DTDST, fibronectin matrix and condensation. PMID:25146392

  4. In Vitro Analysis of Fibronectin-Modified Titanium Surfaces

    PubMed Central

    Chang, Yu-Chi; Lee, Wei-Fang; Feng, Sheng-Wei; Huang, Haw-Ming; Lin, Che-Tong; Teng, Nai-Chia; Chang, Wei Jen

    2016-01-01

    Background Glow discharge plasma (GDP) procedure is an effective method for grafting various proteins, including albumin, type I collagen, and fibronectin, onto a titanium surface. However, the behavior and impact of titanium (Ti) surface modification is yet to be unraveled. Purpose The purpose of this study is to evaluate and analyze the biological properties of fibronectin-grafted Ti surfaces treated by GDP. Materials and Methods Grade II Ti discs were initially cleaned and autoclaved to obtain original specimens. Subsequently, the specimens were GDP treated and grafted with fibronectin to form Ar-GDP (Argon GDP treatment only) and GDP-fib (fibronectin coating following GDP treatment) groups. Blood coagulation test and MG-63 cell culture were performed to evaluate the biological effects on the specimen. Results There was no significant difference between Ar-GDP and GDP-fib groups in blood compatibility analysis. While in the MTT test, cellular proliferation was benefited from the presence of fibronectin coating. The numbers of cells on Ar-GDP and GDP-fib specimens were greater than those in the original specimens after 24 h of culturing. Conclusions GDP treatment combined with fibronectin grafting favored MG-63 cell adhesion, migration, and proliferation on titanium surfaces, which could be attributed to the improved surface properties. PMID:26731536

  5. Fibronectin receptors of mononuclear phagocytes: Binding characteristics and biochemical isolation

    SciTech Connect

    Garcia-Pardo, A.; Ferreira, O.C.; Valinsky, J.; Bianco, C. )

    1989-04-01

    Fibronectin receptors on mononuclear phagocytes are involved in the localization of monocytes at inflammatory sites and in the subsequent expression of macrophage-like phenotypes. In this study, the authors have investigated the hypothesis that preteolytically derived fragments of fibronectin may interfere with binding of fibronectin to monocytes in the extracellular matrix. They report on the reactivity of U937 cells with an 80-kDa tryptic fragment of fibronectin which contains the cell-binding domain but lacks the gelatin/collagen-binding domain. U937 cells attached to surfaces coated with the 80-kDa fragment as well as with intact fibronectin. Preincubation of the cells with the 80-kDa fragment inhibited attachment to both surfaces while intact fibronectin had little or no inhibitory effect. This complex resolved into a single diffuse band of 144 kDa upon reduction. Binding of the protein complex to the affinity column required divalent cations. The complex bound to wheat germ agglutinin and could be specifically eluted by N-acetylglucosamine. Similar cell-surface proteins were isolated from peripheral blood monocytes.

  6. Fibronectin Inhibits Chronic Pain Development after Spinal Cord Injury

    PubMed Central

    Lee, Yu-Shang; Lin, Vernon W.; Silver, Jerry

    2012-01-01

    Abstract Chronic pain following spinal cord injury (SCI) is a highly prevalent clinical condition that is difficult to treat. Using both von Frey filaments and radiant infrared heat to assess mechanical allodynia and thermal hyperalgesia, respectively, we have demonstrated that a one-time injection of fibronectin (50 μg/mL) into the spinal dorsal column (1 μL/min each injection for a total of 5 μL) immediately after SCI inhibits the development of mechanical allodynia (but not thermal hyperalgesia) over an 8-month observation period following spinal cord dorsal column crush (DCC). DCC will only induce mechanical Allodynia, but not thermal hyperalgesia or overt motor deficits. By applying various fibronectin fragments as well as competitive inhibitors, these effects were shown to be dependent on the connecting segment-1 (CS-1) motif of fibronectin. Furthermore, we found that acute fibronectin treatment diminished inflammation and blood–spinal cord barrier permeability, which in turn leads to enhanced fiber sparing and sprouting. In particular, the reduction of serotonin (5-HT) in the superficial dorsal horn, an important descending brainstem system in the modulation of pain, was blocked with fibronectin treatment. We conclude that treatment of SCI with fibronectin preserves sensory regulation and prevents the development of chronic allodynia, providing a potential therapeutic intervention to treat chronic pain following SCI. PMID:22022865

  7. Tendon synovial cells secrete fibronectin in vivo and in vitro

    SciTech Connect

    Banes, A.J.; Link, G.W.; Bevin, A.G.; Peterson, H.D.; Gillespie, Y.; Bynum, D.; Watts, S.; Dahners, L.

    1988-01-01

    The chemistry and cell biology of the tendon have been largely overlooked due to the emphasis on collagen, the principle structural component of the tendon. The tendon must not only transmit the force of muscle contraction to bone to effect movement, but it must also glide simultaneously over extratendonous tissues. Fibronectin is classified as a cell attachment molecule that induces cell spreading and adhesion to substratum. The external surface of intact avian flexor tendon stained positively with antibody to cellular fibronectin. However, if the surface synovial cells were first removed with collagenase, no positive reaction with antifibronectin antibody was detected. Analysis of immunologically stained frozen sections of tendon also revealed fibronectin at the tendon synovium, but little was associated with cells internal in tendon. The staining pattern with isolated, cultured synovial cells and fibroblasts from the tendon interior substantiated the histological observations. Analysis of polyacrylamide gel profiles of /sup 35/S-methionine-labeled proteins synthesized by synovial cells and internal fibroblasts indicated that fibronectin was synthesized principally by synovial cells. Fibronectin at the tendon surface may play a role in cell attachment to prevent cell removal by the friction of gliding. Alternatively, fibronectin, with its binding sites for hyaluronic acid and collagen, may act as a complex for boundary lubrication.

  8. Integrin activation and focal complex formation in cardiac hypertrophy

    NASA Technical Reports Server (NTRS)

    Laser, M.; Willey, C. D.; Jiang, W.; Cooper, G. 4th; Menick, D. R.; Zile, M. R.; Kuppuswamy, D.

    2000-01-01

    Cardiac hypertrophy is characterized by both remodeling of the extracellular matrix (ECM) and hypertrophic growth of the cardiocytes. Here we show increased expression and cytoskeletal association of the ECM proteins fibronectin and vitronectin in pressure-overloaded feline myocardium. These changes are accompanied by cytoskeletal binding and phosphorylation of focal adhesion kinase (FAK) at Tyr-397 and Tyr-925, c-Src at Tyr-416, recruitment of the adapter proteins p130(Cas), Shc, and Nck, and activation of the extracellular-regulated kinases ERK1/2. A synthetic peptide containing the Arg-Gly-Asp (RGD) motif of fibronectin and vitronectin was used to stimulate adult feline cardiomyocytes cultured on laminin or within a type-I collagen matrix. Whereas cardiocytes under both conditions showed RGD-stimulated ERK1/2 activation, only collagen-embedded cells exhibited cytoskeletal assembly of FAK, c-Src, Nck, and Shc. In RGD-stimulated collagen-embedded cells, FAK was phosphorylated only at Tyr-397 and c-Src association occurred without Tyr-416 phosphorylation and p130(Cas) association. Therefore, c-Src activation is not required for its cytoskeletal binding but may be important for additional phosphorylation of FAK. Overall, our study suggests that multiple signaling pathways originate in pressure-overloaded heart following integrin engagement with ECM proteins, including focal complex formation and ERK1/2 activation, and many of these pathways can be activated in cardiomyocytes via RGD-stimulated integrin activation.

  9. Expression of fibronectin, fibronectin isoforms and integrin receptors in melanocytic lesions.

    PubMed Central

    Natali, P. G.; Nicotra, M. R.; Di Filippo, F.; Bigotti, A.

    1995-01-01

    In vitro studies have demonstrated that fibronectin (FN) can deliver a mitogenic signal to quiescent human melanoma cells and that the alpha 5/beta 1-integrin receptor mediates this stimulus. In view of this finding we have analysed the in vivo expression of FN, and of ED-A and ED-B FN isoforms, in benign and malignant lesions of melanocyte origin. In the same specimens the expression of fibronectin integrin receptors was evaluated. The results demonstrate that, while detection of FN does not correlate with transformation and tumour progression, the expression of the two isoforms is associated with transformation and that only the ED-A variant is found in metastases. Integrin phenotyping disclosed that alpha 3/beta 1 expression is associated with tumour progression, alpha v/beta 3 is a marker of transformation, alpha 4 is rarely expressed and alpha 5 is expressed by about 50% and 30% of the primary and metastatic lesions respectively. Taken together, the results of this study demonstrate that transformation and tumour progression of the melanocyte lineage are associated with modulation of expression of FN isoforms and FN integrin receptors. Furthermore, the expression of alpha 5-integrin in a considerable percentage of primary and metastatic lesions indicates that FN may deliver a proliferative stimulus to melanoma cells in vivo. Images Figure 1 PMID:7779718

  10. Purification of a mycobacterial adhesin for fibronectin.

    PubMed Central

    Ratliff, T L; McCarthy, R; Telle, W B; Brown, E J

    1993-01-01

    Previous studies have demonstrated that mycobacteria attach to fibronectin (FN). The attachment of mycobacteria to FN is considered to be biologically important in Mycobacterium bovis BCG therapy for superficial bladder cancer, initiation of delayed hypersensitivity to mycobacterial antigens, and the phagocytosis of mycobacteria by epithelial cells. Therefore, we purified the mycobacterial receptor for FN. Culture supernatants from 3-week cultures of Mycobacterium vaccae, which contained proteins that bound FN and inhibited the attachment of both M. vaccae and BCG to FN, were used as a source of receptor. Lyophilized M. vaccae supernatants were reconstituted in 0.02 M bis-Tris (pH 6.0) and applied sequentially to an ACA 54 gel filtration column and a DEAE-Sephacel anion-exchange column. A purified inhibitory protein of 55 kDa (p55) was obtained. The purified p55 protein was observed to bind to FN and to inhibit 125I-FN binding to viable BCG in a dose-dependent manner. Polyclonal and monoclonal antibodies to the protein were generated. The resulting polyclonal antiserum blotted a single protein band at 55 kDa in crude M. vaccae supernatants, cross-reacted with a 55-kDa BCG protein by Western blot (immunoblot), and recognized a 55-kDa band that was associated with the BCG cell wall, which is consistent with its function as a FN receptor. A monoclonal immunoglobulin M(lambda) was isolated from mice immunized with purified M. vaccae p55 protein that was not functional in Western blots but inhibited the attachment of viable BCG to FN. These studies demonstrate that a protein or antigenically related proteins with M(r)s of 55,000 function as FN receptors for at least two distinct mycobacteria. Images PMID:8478078

  11. Focal neurological deficits

    MedlinePlus

    A focal neurologic deficit is a problem with nerve, spinal cord, or brain function. It affects a specific ... of the back, neck, or head Electromyogram (EMG)/ nerve conduction velocities (NCV) MRI of the back, neck, or head Spinal tap

  12. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff RB, ... 6th ed. Philadelphia, PA: Elsevier Saunders; 2012:chap 67. ...

  13. Partial (focal) seizure

    MedlinePlus

    ... Jacksonian seizure; Seizure - partial (focal); Temporal lobe seizure; Epilepsy - partial seizures ... Abou-Khalil BW, Gallagher MJ, Macdonald RL. Epilepsies. In: Daroff ... Practice . 7th ed. Philadelphia, PA: Elsevier; 2016:chap 101. ...

  14. Focal vibration in neurorehabilitation.

    PubMed

    Murillo, N; Valls-Sole, J; Vidal, J; Opisso, E; Medina, J; Kumru, H

    2014-04-01

    During the last decade, many studies have been carried out to understand the effects of focal vibratory stimuli at various levels of the central nervous system and to study pathophysiological mechanisms of neurological disorders as well as the therapeutic effects of focal vibration in neurorehabilitation. This review aimed to describe the effects of focal vibratory stimuli in neurorehabilitation including the neurological diseases or disorders like stroke, spinal cord injury, multiple sclerosis, Parkinson's' disease and dystonia. In conclusion, focal vibration stimulation is well tolerated, effective and easy to use, and it could be used to reduce spasticity, to promote motor activity and motor learning within a functional activity, even in gait training, independent from etiology of neurological pathology. Further studies are needed in the future well-designed trials with bigger sample size to determine the most effective frequency, amplitude and duration of vibration application in the neurorehabilitation. PMID:24842220

  15. Mesothelial cells promote early ovarian cancer metastasis through fibronectin secretion

    PubMed Central

    Kenny, Hilary A.; Chiang, Chun-Yi; White, Erin A.; Schryver, Elizabeth M.; Habis, Mohammed; Romero, Iris L.; Ladanyi, Andras; Penicka, Carla V.; George, Joshy; Matlin, Karl; Montag, Anthony; Wroblewski, Kristen; Yamada, S. Diane; Mazar, Andrew P.; Bowtell, David; Lengyel, Ernst

    2014-01-01

    Ovarian cancer (OvCa) metastasizes to organs in the abdominal cavity, such as the omentum, which are covered by a single layer of mesothelial cells. Mesothelial cells are generally thought to be “bystanders” to the metastatic process and simply displaced by OvCa cells to access the submesothelial extracellular matrix. Here, using organotypic 3D cultures, we found that primary human mesothelial cells secrete fibronectin in the presence of OvCa cells. Moreover, we evaluated the tumor stroma of 108 human omental metastases and determined that fibronectin was consistently overexpressed in these patients. Blocking fibronectin production in primary mesothelial cells in vitro or in murine models, either genetically (fibronectin 1 floxed mouse model) or via siRNA, decreased adhesion, invasion, proliferation, and metastasis of OvCa cells. Using a coculture model, we determined that OvCa cells secrete TGF-β1, which in turn activates a TGF-β receptor/RAC1/SMAD-dependent signaling pathway in the mesothelial cells that promotes a mesenchymal phenotype and transcriptional upregulation of fibronectin. Additionally, blocking α5 or β1 integrin function with antibodies reduced metastasis in an orthotopic preclinical model of OvCa metastasis. These findings indicate that cancer-associated mesothelial cells promote colonization during the initial steps of OvCa metastasis and suggest that mesothelial cells actively contribute to metastasis. PMID:25202979

  16. Expression of laminin and fibronectin in renal dysplasia.

    PubMed

    Menon, Santosh; Kakkar, Nandita; Radotra, B D

    2004-01-01

    The pathogenesis of renal dysplasia is a matter of debate. Recent theories have conceptualized the role of extracellular matrix proteins in the genesis of renal dysplasia. During normal nephrogenesis, collagen type I and III and fibronectins are lost and laminin and syndecan appear once proper induction has occurred. Any deviation from the normal pattern is said to lead to dysplasia. In this study, the expressions of adhesive glycoproteins, laminin, and fibronectin were studied immunohistochemically in 25 autopsy cases of renal dysplasia and normal age-matched control cases. These cases of renal dysplasia were categorized into 3 groups based on the period of gestation: 20 to 26 weeks, 27 to 33 weeks, and 34 to 40 weeks. The immunohistochemical findings were graded from 0 to 4+ based on the visual intensity. Chi-square analysis was used to calculate the difference in expressions of laminin and fibronectin in cases and controls as a whole and within and between age groups. Immunostaining for laminin in all age groups showed a significant difference in expression between dysplastic kidneys (less expression) and normal controls (greater expression). In the case of fibronectin expression, all but 1 group showed a significant difference, with dysplastic kidneys showing more and normal controls showing less expression. The inference derived is that laminin expression decreases and fibronectin expression increases in renal dysplasia compared with normal nephrogenesis. PMID:15630524

  17. The dispersion-focalization theory of sound systems

    NASA Astrophysics Data System (ADS)

    Schwartz, Jean-Luc; Abry, Christian; Boë, Louis-Jean; Vallée, Nathalie; Ménard, Lucie

    2005-04-01

    The Dispersion-Focalization Theory states that sound systems in human languages are shaped by two major perceptual constraints: dispersion driving auditory contrast towards maximal or sufficient values [B. Lindblom, J. Phonetics 18, 135-152 (1990)] and focalization driving auditory spectra towards patterns with close neighboring formants. Dispersion is computed from the sum of the inverse squared inter-spectra distances in the (F1, F2, F3, F4) space, using a non-linear process based on the 3.5 Bark critical distance to estimate F2'. Focalization is based on the idea that close neighboring formants produce vowel spectra with marked peaks, easier to process and memorize in the auditory system. Evidence for increased stability of focal vowels in short-term memory was provided in a discrimination experiment on adult French subjects [J. L. Schwartz and P. Escudier, Speech Comm. 8, 235-259 (1989)]. A reanalysis of infant discrimination data shows that focalization could well be the responsible for recurrent discrimination asymmetries [J. L. Schwartz et al., Speech Comm. (in press)]. Recent data about children vowel production indicate that focalization seems to be part of the perceptual templates driving speech development. The Dispersion-Focalization Theory produces valid predictions for both vowel and consonant systems, in relation with available databases of human languages inventories.

  18. [A simple and effective step in the purification of bovine blood fibronectin].

    PubMed

    Zykova, T A; Zlatopol'skiĭ, A D; Mazurov, V I

    1983-01-01

    Preparations of fibronectin from bovine blood serum, obtained by means of affinity chromatography on collagen-Sepharose, contained immunoglobulins and other proteins, concentration of which constituted 48 +/- 5%. Differential salting out of fibronectin and other non-fibronectin proteins, using 0.8-2.0 M ammonium sulfate at pH 5.0, demonstrated that precipitation of fibronectin occurred more effectively as compared with non-fibronectin proteins at all the salt concentrations studied. If 0.8 M or 1.0 M ammonium sulfate concentrations were used, the fibronectin preparations contained less than 10% of other proteins and fibronectin loss was about 20%. Salting out of fibronectin is an effective additional step of its purification. PMID:6649521

  19. Fibronectin Binds to Some Bacteria but Does not Promote Their Uptake by Phagocytic Cells

    NASA Astrophysics Data System (ADS)

    van de Water, L.; Destree, A. T.; Hynes, R. O.

    1983-04-01

    The involvement of plasma fibronectin in phagocytosis of bacteria was investigated by testing the binding of fibronectin to several species of bacteria and by evaluating the ability of fibronectin to promote binding and endocytosis of two species of these bacteria by phagocytic cells. Fibronectin binds non-covalently to Gram-positive and Gram-negative bacteria and to yeast but did not appear to be necessary or sufficient for uptake of Staphylococcus aureus and Salmonella typhimurium by several different phagocytic cell types.

  20. Display of Cell Surface Sites for Fibronectin Assembly Is Modulated by Cell Adherence to 1F3 and C-Terminal Modules of Fibronectin

    PubMed Central

    Zhang, Qinghong; Annis, Douglas S.; Erickson, Harold P.; Mosher, Deane F.

    2009-01-01

    Background Fibronectin-null cells assemble soluble fibronectin shortly after adherence to a substrate coated with intact fibronectin but not when adherent to the cell-binding domain of fibronectin (modules 7F3-10F3). Interactions of adherent cells with regions of adsorbed fibronectin other than modules 7F3-10F3, therefore, are required for early display of the cell surface sites that initiate and direct fibronectin assembly. Methodology/Principal Findings To identify these regions, coatings of proteolytically derived or recombinant pieces of fibronectin containing modules in addition to 7F3-10F3 were tested for effects on fibronectin assembly by adherent fibronectin-null fibroblasts. Pieces as large as one comprising modules 2F3-14F3, which include the heparin-binding and cell adhesion domains, were not effective in supporting fibronectin assembly. Addition of module 1F3 or the C-terminal modules to modules 2F3-14F3 resulted in some activity, and addition of both 1F3 and the C-terminal modules resulted in a construct, 1F3-C, that best mimicked the activity of a coating of intact fibronectin. Constructs 1F3-C V0, 1F3-C V64, and 1F3-C Δ(V15F310F1) were all able to support fibronectin assembly, suggesting that 1F3 through 11F1 and/or 12F1 were important for activity. Coatings in which the active parts of 1F3-C were present in different proteins were much less active than intact 1F3-C. Conclusions These results suggest that 1F3 acts together with C-terminal modules to induce display of fibronectin assembly sites on adherent cells. PMID:19119318

  1. SNAP focal plane

    SciTech Connect

    Lampton, Michael L.; Kim, A.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Berkovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro,R.; Ealet, A.; Ellis, R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland, S.E.; Huterer, D.; Karcher, A.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder,E.V.; Loken, S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto, E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.

    2002-07-29

    The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square-degree field sensitive in the visible and near-infrared wavelength regime. We describe the requirements for the instrument suite and the evolution of the focal plane design to the present concept in which all the instrumentation--visible and near-infrared imagers, spectrograph, and star guiders--share one common focal plane.

  2. Selective Cell Growth on Fibronectin-Carbon Nanotube Hybrid Nanostructures

    NASA Astrophysics Data System (ADS)

    Namgung, Seon; Park, Sung Young; Lee, Byung Yang; Lee, Minbaek; Nam, Jwa-Min; Hong, Seunghun

    2008-03-01

    Carbon nanotubes (CNT) have been considered a promising material for biological applications including biosensors, therapeutic application, and nano-structured scaffolds. However, there are still controversies associated with toxicity and biocompatibility of CNTs on live cells. Here, we report general strategy to functionalize CNTs with cell adhesion molecules (fibronectins) for selective and stable adhesion of cells on CNTs. Interestingly, more fibronectins were adsorbed and activated on CNTs rather than on hydrophobic self assembled monolayers (SAMs) or bare substrates (SiO2). We demonstrate the functionality of fibronectins on CNTs with immunofluorescence and molecule-level force measurement study using atomic force microscopy (AFM). These fibronectin-CNT hybrid nanostructures were successfully applied to attract cells selectively onto predefined regions on the substrate. Our strategy was generally available on various cell types including mesenchymal stem cells, KB cells, and NIH3T3 fibroblast cells (Advanced Materials 19, 2530-2534 (2007)). We will also discuss about its impacts on cell biology combined with CNTs.

  3. Detection of fibronectin receptor in sera: its clinical significance as a parameter of hepatic fibrosis.

    PubMed

    Yamauchi, M; Nakajima, H; Ohata, M; Hirakawa, J; Mizuhara, Y; Nakahara, M; Kimura, K; Fujisawa, K; Kameda, H

    1991-08-01

    Pooled sera collected from cirrhotic patients was fractionated by affinity chromatography with a fibronectin receptor monoclonal antibody against the beta-subunit of fibronectin receptor. Eluates were assayed using Western immunoblotting. The relative mobility of the protein reactive with fibronectin receptor antibody was nearly identical to that of the beta-subunit of fibronectin receptor, confirming that fibronectin receptor is present in human serum. Serum levels of the beta-subunit of fibronectin receptor were analyzed by sandwich enzyme-linked immunosorbent assay in patients with various liver diseases. The serum level of fibronectin receptor (micrograms/ml) was significantly higher in patients with chronic hepatitis (inactive, 2.59 +/- 0.04; active, 3.45 +/- 0.13), cirrhosis (4.77 +/- 0.30), alcoholic liver disease (2.96 +/- 0.16) and hepatocellular carcinoma (4.71 +/- 0.49) than in normal subjects (2.11 +/- 0.08). Strong positive correlation was observed between serum levels of fibronectin receptor and histological findings, particularly in the degree of hepatic fibrosis. Immunohistochemical studies with fibronectin receptor antibody revealed that the beta-subunit of fibronectin receptor was present on the plasma membrane of hepatocytes and sinusoidal lining cells in the normal liver and was increased in fibrotic areas and on the plasma membrane of hepatocytes and sinusoidal lining cells of fibrotic liver. The serum level of fibronectin receptor in patients with chronic liver diseases may therefore be a useful marker of hepatic fibrosis. PMID:1830562

  4. Focal adhesions, stress fibers and mechanical tension

    PubMed Central

    Burridge, Keith; Guilluy, Christophe

    2016-01-01

    Stress fibers and focal adhesions are complex protein arrays that produce, transmit and sense mechanical tension. Evidence accumulated over many years led to the conclusion that mechanical tension generated within stress fibers contributes to the assembly of both stress fibers themselves and their associated focal adhesions. However, several lines of evidence have recently been presented against this model. Here we discuss the evidence for and against the role of mechanical tension in driving the assembly of these structures. We also consider how their assembly is influenced by the rigidity of the substratum to which cells are adhering. Finally, we discuss the recently identified connections between stress fibers and the nucleus, and the roles that these may play, both in cell migration and regulating nuclear function. PMID:26519907

  5. Allosteric Regulation of Fibronectin/α5β1 Interaction by Fibronectin-Binding MSCRAMMs

    PubMed Central

    Liang, Xiaowen; Garcia, Brandon L.; Visai, Livia; Prabhakaran, Sabitha; Meenan, Nicola A. G.; Potts, Jennifer R.; Humphries, Martin J.; Höök, Magnus

    2016-01-01

    Adherence of microbes to host tissues is a hallmark of infectious disease and is often mediated by a class of adhesins termed MSCRAMMs (Microbial Surface Components Recognizing Adhesive Matrix Molecules). Numerous pathogens express MSCRAMMs that specifically bind the heterodimeric human glycoprotein fibronectin (Fn). In addition to roles in adhesion, Fn-binding MSCRAMMs exploit physiological Fn functions. For example, several pathogens can invade host cells by a mechanism whereby MSCRAMM-bound Fn bridges interaction with α5β1 integrin. Here, we investigate two Fn-binding MSCRAMMs, FnBPA (Staphylococcus aureus) and BBK32 (Borrelia burgdorferi) to probe structure-activity relationships of MSCRAMM-induced Fn/α5β1integrin activation. Circular dichroism, fluorescence resonance energy transfer, and dynamic light scattering techniques uncover a conformational rearrangement of Fn involving domains distant from the MSCRAMM binding site. Surface plasmon resonance experiments demonstrate a significant enhancement of Fn/α5β1 integrin affinity in the presence of FnBPA or BBK32. Detailed kinetic analysis of these interactions reveal that this change in affinity can be attributed solely to an increase in the initial Fn/α5β1 on-rate and that this rate-enhancement is dependent on high-affinity Fn-binding by MSCRAMMs. These data implicate MSCRAMM-induced perturbation of specific intramolecular contacts within the Fn heterodimer resulting in activation by exposing previously cryptic α5β1 interaction motifs. By correlating structural changes in Fn to a direct measurement of increased Fn/α5β1 affinity, this work significantly advances our understanding of the structural basis for the modulation of integrin function by Fn-binding MSCRAMMs. PMID:27434228

  6. Requirement of focal adhesion kinase in branching tubulogenesis.

    PubMed

    Wei, Wei-Chun; Kopec, Anna K; Tang, Ming-Jer

    2009-01-01

    We previously demonstrated that alpha3beta1 integrins are essential to hepatocyte growth factor (HGF)-independent branching tubulogenesis in Mardin-Darby Canine Kidney (MDCK) cells. However, the involvement of integrin downstream signaling molecules remains unclear. In the present study, we successfully isolated cell lines possessing different tubulogenic potentials from the MDCK cells; cyst clones (CA4, CA6) forming cystic structures when cultured in 0.3% type I collagen gel and mass clones (M610, M611, M612) forming aggregated masses. Cyst clones maintained cystic structure in 0.1% collagen gel, whereas mass clones spontaneously developed into tubules. Both clones exhibited various morphologies when cultured on a dish: cyst clones formed aggregated islands, while mass clones were more scattered and exhibited higher migration capacity. Among several focal adhesion machinery proteins examined, only the expression and phosphorylation level of focal adhesion kinase (FAK) in mass clones was higher than in cyst clones, while other proteins showed no obvious differences. However, overexpression of wild type FAK in CA6 cells did not facilitate branching tubule formation in 0.1% collagen gel. Targeted decrease in the expression level of FAK in M610 cells with the application of antisense cDNA resulted in a marked reduction of branching tubule formation in 0.1% collagen gel and showed a down-regulation of fibronectin assembly, which is known to promote tubulogenesis. In contrast, overexpression of wild type FAK in CA6 cells had no effect on fibronectin assembly. Taken together, our data demonstrates that FAK is required, but not sufficient for HGF-independent branching tubulogenesis in MDCK cells. PMID:19272169

  7. Demonstration of fibronectin in human articular cartilage by an indirect immunoperoxidase technique.

    PubMed

    Clemmensen, I; Hølund, B; Johansen, N; Andersen, R B

    1982-01-01

    Fresh frozen tissue sections of human articular cartilage was treated without and with human testicular hyaluronidase (2 x 10(6) units/l) for 60 min at 37 degrees C and stained by the indirect immunoperoxidase technique with rabbit antihuman fibronectin. The rabbit antihuman fibronectin was purified by affinity chromatography on human fibronectin-Sepharose. Fibronectin was only found on the acellular surface of the articular cartilage in tissue sections not treated with hyaluronidase. In this surface layer, probably identical to "lamina splendens", the arrangement of fibronectin was as a membrane. No collagen was seen in this area by van Gieson staining. No staining for fibronectin was found in the cartilage matrix or in the chondrocytes. Treatment of the cartilage tissue with hyaluronidase resulted in visualization of high amount of fibronectin in the cartilage matrix, with the highest intensity around the chondrocytes. The staining of the acellular surface layer of the articular cartilage was identical with the results obtained without hyaluronidase treatment. These results indicate that articular cartilage is rich in fibronectin probably in complex with hyaluronic acid, and that the chondrocytes produce fibronectin in situ. It also demonstrates the steric hindrance of hyaluronic acid aggregates in diffusion of the antibody and the value of hyaluronidase treatment of tissue before demonstration of fibronectin. PMID:6757202

  8. Dexamethasone-Mediated Activation of Fibronectin Matrix Assembly Reduces Dispersal of Primary Human Glioblastoma Cells

    PubMed Central

    Shannon, Stephen; Vaca, Connan; Jia, Dongxuan; Entersz, Ildiko; Schaer, Andrew; Carcione, Jonathan; Weaver, Michael; Avidar, Yoav; Pettit, Ryan; Nair, Mohan; Khan, Atif; Foty, Ramsey A.

    2015-01-01

    Despite resection and adjuvant therapy, the 5-year survival for patients with Glioblastoma multiforme (GBM) is less than 10%. This poor outcome is largely attributed to rapid tumor growth and early dispersal of cells, factors that contribute to a high recurrence rate and poor prognosis. An understanding of the cellular and molecular machinery that drive growth and dispersal is essential if we are to impact long-term survival. Our previous studies utilizing a series of immortalized GBM cell lines established a functional causation between activation of fibronectin matrix assembly (FNMA), increased tumor cohesion, and decreased dispersal. Activation of FNMA was accomplished by treatment with Dexamethasone (Dex), a drug routinely used to treat brain tumor related edema. Here, we utilize a broad range of qualitative and quantitative assays and the use of a human GBM tissue microarray and freshly-isolated primary human GBM cells grown both as conventional 2D cultures and as 3D spheroids to explore the role of Dex and FNMA in modulating various parameters that can significantly influence tumor cell dispersal. We show that the expression and processing of fibronectin in a human GBM tissue-microarray is variable, with 90% of tumors displaying some abnormality or lack in capacity to secrete fibronectin or assemble it into a matrix. We also show that low-passage primary GBM cells vary in their capacity for FNMA and that Dex treatment reactivates this process. Activation of FNMA effectively “glues” cells together and prevents cells from detaching from the primary mass. Dex treatment also significantly increases the strength of cell-ECM adhesion and decreases motility. The combination of increased cohesion and decreased motility discourages in vitro and ex vivo dispersal. By increasing cell-cell cohesion, Dex also decreases growth rate of 3D spheroids. These effects could all be reversed by an inhibitor of FNMA and by the glucocorticoid receptor antagonist, RU-486. Our

  9. Fish Rhabdovirus Cell Entry Is Mediated by Fibronectin

    PubMed Central

    Bearzotti, Monique; Delmas, Bernard; Lamoureux, Annie; Loustau, Anne-Marie; Chilmonczyk, Stefan; Bremont, Michel

    1999-01-01

    Three monoclonal antibodies (MAbs) generated against rainbow trout gonad cells (RTG-2) have been selected for their ability to protect cells from the viral hemorrhagic septicemia virus (VHSV) infection, a salmonid rhabdovirus. Protection from infection was restricted to the salmonid-derived cell lines indicating species specificity of the blocking MAbs. Surprisingly, the blocking activity of these MAbs was also effective against other nonantigenically related fish rhabdoviruses. Indirect immunofluorescence and immunoelectron microscopy observations demonstrated that the three MAbs were all directed against an abundant cell plasma membrane component, and immunoprecipitation studies indicated that the target consisted of a heterodimeric complex with molecular masses of 200 and 44 kDa. Biochemical data provided the following evidence that fibronectin is part of this complex and that it could represent the main receptor for fish rhabdoviruses. (i) An antiserum generated against the 200-kDa protein reacted against the recombinant rainbow trout fibronectin expressed in Escherichia coli. (ii) The purified rainbow trout fibronectin was able to bind specifically to VHSV. To our knowledge, this is the first identification of a cellular component acting as a primary receptor for a virus replicating in lower vertebrates and, more interestingly, for viruses belonging to the Rhabdoviridae family. PMID:10438860

  10. Improved interaction of osteoblast-like cells with apatite-nanodiamond coatings depends on fibronectin.

    PubMed

    Hristova, K; Pecheva, E; Pramatarova, L; Altankov, G

    2011-08-01

    New apatite (AP)/nanodiamond (ND) coating has been developed to improve physical and biological properties of stainless steel (SS) versus single AP coating. Homogeneously electrodeposited AP-ND layer demonstrates increased mechanical strength, interlayer cohesion and ductility. In the absence of serum, osteoblast-like MG63 cells attach well but poorly spread on both AP and AP-ND substrata. Pre-adsorption with serum or fibronectin (FN) improves the cellular interaction-an effect that is better pronounced on the AP-ND coating. In single protein adsorption study fluorescein isothiocyanate-labeled FN (FITC-FN) shows enhanced deposition on the AP-ND layer consistent with the significantly improved cell adhesion, spreading and focal adhesions formation (in comparison to SS and AP), particularly at low FN adsorption concentrations (1 μg/ml). Higher FN concentrations (20 μg/ml) abolish this difference suggesting that the promoted cellular interaction of serum (where FN is low) is caused by the greater affinity for FN. Moreover, it is found that MG63 cells tend to rearrange both adsorbed and secreted FN on the AP-ND layer suggesting facilitated FN matrix formation. PMID:21706219

  11. Suberoylanilide hydroxamic acid (SAHA) at subtoxic concentrations increases the adhesivity of human leukemic cells to fibronectin.

    PubMed

    Kuzelová, Katerina; Pluskalová, Michaela; Brodská, Barbora; Otevrelová, Petra; Elknerová, Klára; Grebenová, Dana; Hrkal, Zbynek

    2010-01-01

    Suberoylanilide hydroxamic acid (SAHA) is an inhibitor of histone deacetylases (HDACs) which is being introduced into clinic for the treatment of hematological diseases. We studied the effect of this compound on six human hematopoietic cell lines (JURL-MK1, K562, CML-T1, Karpas-299, HL-60, and ML-2) as well as on normal human lymphocytes and on leukemic primary cells. SAHA induced dose-dependent and cell type-dependent cell death which displayed apoptotic features (caspase-3 activation and apoptotic DNA fragmentation) in most cell types including the normal lymphocytes. At subtoxic concentrations (0.5-1 microM), SAHA increased the cell adhesivity to fibronectin (FN) in all leukemia/lymphoma-derived cell lines but not in normal lymphocytes. This increase was accompanied by an enhanced expression of integrin beta1 and paxillin, an essential constituent of focal adhesion complexes, both at the protein and mRNA level. On the other hand, the inhibition of ROCK protein, an important regulator of cytoskeleton structure, had no consistent effect on SAHA-induced increase in the cell adhesivity. The promotion of cell adhesivity to FN seems to be specific for SAHA as we observed no such effects with other HDAC inhibitors (trichostatin A and sodium butyrate). PMID:19911379

  12. Evolutionary connections between coding and splicing regulatory regions in the fibronectin EDA exon.

    PubMed

    Zago, Paola; Buratti, Emanuele; Stuani, Cristiana; Baralle, Francisco E

    2011-08-01

    Research on exonic coding sequences has demonstrated that many substitutions at the amino acid level may also reflect profound changes at the level of splicing regulatory regions. These results have revealed that, for many alternatively spliced exons, there is considerable pressure to strike a balance between two different and sometimes conflicting forces: the drive to improve the quality and production efficiency of proteins and the maintenance of proper exon recognition by the splicing machinery. Up to now, the systems used to investigate these connections have mostly focused on short alternatively spliced exons that contain a high density of splicing regulatory elements. Although this is obviously a desirable feature in order to maximize the chances of spotting connections, it also complicates the process of drawing straightforward evolutionary pathways between different species (because of the numerous alternative pathways through which the same end point can be achieved). The alternatively spliced fibronectin extra domain A exon (also referred to as EDI or EIIIA) does not have these limitations, as its inclusion is already known to depend on a single exonic splicing enhancer element within its sequence. In this study, we have compared the rat and human fibronectin EDA exons with regard to RNA structure, exonic splicing enhancer strengths, and SR protein occupancy. The results gained from these analyses have then been used to perform an accurate evaluation of EDA sequences observed in a wide range of animal species. This comparison strongly suggests the existence of an evolutionary connection between changes at the nucleotide levels and the need to maintain efficient EDA recognition in different species. PMID:21663748

  13. Focal adhesions in osteoneogenesis

    PubMed Central

    Biggs, M.J.P; Dalby, M.J

    2010-01-01

    As materials technology and the field of tissue engineering advances, the role of cellular adhesive mechanisms, in particular the interactions with implantable devices, becomes more relevant in both research and clinical practice. A key tenet of medical device technology is to use the exquisite ability of biological systems to respond to the material surface or chemical stimuli in order to help develop next-generation biomaterials. The focus of this review is on recent studies and developments concerning focal adhesion formation in osteoneogenesis, with an emphasis on the influence of synthetic constructs on integrin mediated cellular adhesion and function. PMID:21287830

  14. Nuclear transport of paxillin depends on focal adhesion dynamics and FAT domains

    PubMed Central

    Sathe, Aneesh R.; Shivashankar, G. V.; Sheetz, Michael P.

    2016-01-01

    ABSTRACT The nuclear transport of paxillin appears to be crucial for paxillin function but the mechanism of transport remains unclear. Here, we show that the nuclear transport of paxillin is regulated by focal adhesion turnover and the presence of FAT domains. Focal adhesion turnover was controlled using triangular or circular fibronectin islands. Circular islands caused higher focal adhesion turnover and increased the nuclear transport of paxillin relative to triangular islands. Mutating several residues of paxillin had no effect on its nuclear transport, suggesting that the process is controlled by multiple domains. Knocking out FAK (also known as PTK2) and vinculin caused an increase in nuclear paxillin. This could be reversed by rescue with wild-type FAK but not by FAK with a mutated FAT domain, which inhibits paxillin binding. Expressing just the FAT domain of FAK not only brought down nuclear levels of paxillin but also caused a large immobile fraction of paxillin to be present at focal adhesions, as demonstrated by fluorescence recovery after photobleaching (FRAP) studies. Taken together, focal adhesion turnover and FAT domains regulate the nuclear localization of paxillin, suggesting a possible role for transcriptional control, through paxillin, by focal adhesions. PMID:27068537

  15. Self-assembly of fibronectin mimetic peptide-amphiphile nanofibers

    NASA Astrophysics Data System (ADS)

    Rexeisen, Emilie Lynn

    Many therapeutic strategies incorporate peptides into their designs to mimic the natural protein ligands found in vivo. A few examples are the short peptide sequences RGD and PHSRN that mimic the primary and synergy-binding domains of the extracellular matrix protein, fibronectin, which is recognized by the cell surface receptor, alpha5beta 1 integrin. Even though scaffold modification with biomimetic peptides remains one of the most promising approaches for tissue engineering, the use of these peptides in therapeutic tissue-engineered products and drug delivery systems available on the commercial market is limited because the peptides are not easily able to mimic the natural protein. The design of a peptide that can effectively target the alpha5beta1 integrin would greatly increase biomimetic scaffold therapeutic potential. A novel peptide containing both the RGD primary binding domain and PHSRN synergy-binding domain for fibronectin joined with the appropriate linker should bind alpha 5beta1 integrin more efficiently and lead to greater cell adhesion over RGD alone. Several fibronectin mimetic peptides were designed and coupled to dialkyl hydrocarbon tails to make peptide-amphiphiles. The peptides contained different linkers connecting the two binding domains and different spacers separating the hydrophobic tails from the hydrophilic headgroups. The peptide-amphiphiles were deposited on mica substrates using the Langmuir-Blodgett technique. Langmuir isotherms indicated that the peptide-amphiphiles that contained higher numbers of serine residues formed a more tightly packed monolayer, but the increased number of serines also made transferring the amphiphiles to the mica substrate more difficult. Atomic force microscopy (AFM) images of the bilayers showed that the headgroups might be bent, forming small divots in the surface. These divots may help expose the PHSRN synergy-binding domain. Parallel studies undertaken by fellow group members showed that human

  16. iDriving (Intelligent Driving)

    Energy Science and Technology Software Center (ESTSC)

    2012-09-17

    iDriving identifies the driving style factors that have a major impact on fuel economy. An optimization framework is used with the aim of optimizing a driving style with respect to these driving factors. A set of polynomial metamodels is constructed to reflect the responses produced in fuel economy by changing the driving factors. The optimization framework is used to develop a real-time feedback system, including visual instructions, to enable drivers to alter their driving stylesmore » in responses to actual driving conditions to improve fuel efficiency.« less

  17. iDriving (Intelligent Driving)

    SciTech Connect

    Malikopoulos, Andreas

    2012-09-17

    iDriving identifies the driving style factors that have a major impact on fuel economy. An optimization framework is used with the aim of optimizing a driving style with respect to these driving factors. A set of polynomial metamodels is constructed to reflect the responses produced in fuel economy by changing the driving factors. The optimization framework is used to develop a real-time feedback system, including visual instructions, to enable drivers to alter their driving styles in responses to actual driving conditions to improve fuel efficiency.

  18. A focal adhesion protein-based mechanochemical checkpoint regulates cleft progression during branching morphogenesis

    PubMed Central

    Daley, William P.; Kohn, Joshua M.; Larsen, Melinda

    2011-01-01

    Cleft formation is the initial step of branching morphogenesis in many organs. We previously demonstrated that ROCK 1 regulates a non-muscle myosin II-dependent mechanochemical checkpoint to transition initiated clefts to progressing clefts in developing submandibular salivary glands. Here, we report that ROCK-mediated integrin activation and subsequent formation of focal adhesion complexes comprise this mechanochemical checkpoint. Inhibition of ROCK1 and non-muscle myosin II activity decreased integrin β1 activation in the cleft region and interfered with localization and activation of focal adhesion complex proteins, such as focal adhesion kinase (FAK). Inhibition of FAK activity also prevented cleft progression, by disrupting recruitment of the focal adhesion proteins talin and vinculin and subsequent fibronectin assembly in the cleft region while decreasing ERK1/2 activation. These results demonstrate that inside-out integrin signaling leading to a localized recruitment of active FAK-containing focal adhesion protein complexes generates a mechanochemical checkpoint that facilitates progression of branching morphogenesis. PMID:22016182

  19. Mosaic Focal Plane Development

    NASA Astrophysics Data System (ADS)

    Mason, David L.; Horner, Scott D.; Aamodt, Earl K.

    2002-12-01

    Advances in systems engineering, applied sciences, and manufacturing technologies have enabled the development of large ground based and spaced based astronomical instruments having a large Field of View (FOV) to capture a large portion of the universe in a single image. A larger FOV can be accomplished using light weighted optical elements, improved support structures, and the development of mosaic Focal Plane Assemblies (mFPA). A mFPA designed for astronomy can use multiple Charged Coupled Devices (CCD) mounted onto a single camera baseplate integrated at the instrument plane of focus. Examples of current, or proposed, missions utilizing mFPA technology include FAME, GEST, Kepler, GAIA, LSST, and SNAP. The development of a mFPA mandates tighter control on the design trades, component development, CCD characterization, component integration, and performance verification testing. This paper addresses the capability Lockheed Martin Space Systems Company's (LMSSC) Advanced Technology Center (ATC) has developed to perform CCD characterization, mFPA assembly and alignment, and mFPA system level testing.

  20. Mosaic Focal Plane Development

    NASA Astrophysics Data System (ADS)

    Mason, D.; Horner, S.; Aamodt, E.

    Advances in manufacturing and applied sciences have enabled the development of large ground and spaced based astronomical instruments having a Field of View (FOV) large enough to capture a large portion of the universe in a single image. A large FOV can be accomplished using light weighted optics, improved structures, and the development of mosaic Focal Plane Assemblies (mFPAs). A mFPA comprises multiple Charged Coupled Devices (CCD) mounted onto a single baseplate integrated at the focus plane of the instrument. Examples of current, or proposed, missions utilizing mFPA technology include FAME, GEST, Kepler, GAIA, LSST, and SNAP. The development of a mFPA mandates tight control on the design trades of component development, CCD definition and characterization, component integration, and performance verification testing. This paper addresses the results of the Lockheed Martin Space Systems Company (LMSSC), Advanced Technology Center (ATC) developed mFPA. The design trades and performance characterization are services provided by the LMSSC ATC but not detailed in this paper.

  1. Fibronectin and stem cell differentiation – lessons from chondrogenesis

    PubMed Central

    Singh, Purva; Schwarzbauer, Jean E.

    2012-01-01

    Summary The extracellular matrix (ECM) is an intricate network of proteins that surrounds cells and has a central role in establishing an environment that is conducive to tissue-specific cell functions. In the case of stem cells, this environment is the stem cell niche, where ECM signals participate in cell fate decisions. In this Commentary, we describe how changes in ECM composition and mechanical properties can affect cell shape and stem cell differentiation. Using chondrogenic differentiation as a model, we examine the changes in the ECM that occur before and during mesenchymal stem cell differentiation. In particular, we focus on the main ECM protein fibronectin, its temporal expression pattern during chondrogenic differentiation, its potential effects on functions of differentiating chondrocytes, and how its interactions with other ECM components might affect cartilage development. Finally, we discuss data that support the possibility that the fibronectin matrix has an instructive role in directing cells through the condensation, proliferation and/or differentiation stages of cartilage formation. PMID:22976308

  2. Stretching Fibroblasts Remodels Fibronectin and Alters Cancer Cell Migration

    NASA Astrophysics Data System (ADS)

    Ao, Mingfang; Brewer, Bryson M.; Yang, Lijie; Franco Coronel, Omar E.; Hayward, Simon W.; Webb, Donna J.; Li, Deyu

    2015-02-01

    Most investigations of cancer-stroma interactions have focused on biochemical signaling effects, with much less attention being paid to biophysical factors. In this study, we investigated the role of mechanical stimuli on human prostatic fibroblasts using a microfluidic platform that was adapted for our experiments and further developed for both repeatable performance among multiple assays and for compatibility with high-resolution confocal microscopy. Results show that mechanical stretching of normal tissue-associated fibroblasts (NAFs) alters the structure of secreted fibronectin. Specifically, unstretched NAFs deposit and assemble fibronectin in a random, mesh-like arrangement, while stretched NAFs produce matrix with a more organized, linearly aligned structure. Moreover, the stretched NAFs exhibited an enhanced capability for directing co-cultured cancer cell migration in a persistent manner. Furthermore, we show that stretching NAFs triggers complex biochemical signaling events through the observation of increased expression of platelet derived growth factor receptor α (PDGFRα). A comparison of these behaviors with those of cancer-associated fibroblasts (CAFs) indicates that the observed phenotypes of stretched NAFs are similar to those associated with CAFs, suggesting that mechanical stress is a critical factor in NAF activation and CAF genesis.

  3. Stretching Fibroblasts Remodels Fibronectin and Alters Cancer Cell Migration

    PubMed Central

    Ao, Mingfang; Brewer, Bryson M.; Yang, Lijie; Franco Coronel, Omar E.; Hayward, Simon W.; Webb, Donna J.; Li, Deyu

    2015-01-01

    Most investigations of cancer-stroma interactions have focused on biochemical signaling effects, with much less attention being paid to biophysical factors. In this study, we investigated the role of mechanical stimuli on human prostatic fibroblasts using a microfluidic platform that was adapted for our experiments and further developed for both repeatable performance among multiple assays and for compatibility with high-resolution confocal microscopy. Results show that mechanical stretching of normal tissue-associated fibroblasts (NAFs) alters the structure of secreted fibronectin. Specifically, unstretched NAFs deposit and assemble fibronectin in a random, mesh-like arrangement, while stretched NAFs produce matrix with a more organized, linearly aligned structure. Moreover, the stretched NAFs exhibited an enhanced capability for directing co-cultured cancer cell migration in a persistent manner. Furthermore, we show that stretching NAFs triggers complex biochemical signaling events through the observation of increased expression of platelet derived growth factor receptor α (PDGFRα). A comparison of these behaviors with those of cancer-associated fibroblasts (CAFs) indicates that the observed phenotypes of stretched NAFs are similar to those associated with CAFs, suggesting that mechanical stress is a critical factor in NAF activation and CAF genesis. PMID:25660754

  4. In vitro splicing of fibronectin pre-mRNAs.

    PubMed Central

    Norton, P A; Hynes, R O

    1990-01-01

    We have investigated the alternative splicing of the EIIIB exon of the rat fibronectin gene. Mini-gene constructs containing this exon and portions of adjacent introns and exons, when transfected into HeLa cells, are transcribed and spliced, but omit the EIIIB exon. In vitro, HeLa nuclear extracts similarly splice out (skip) the EIIIB exon from similarly structured transcripts. Therefore, the HeLa splicing apparatus recognizes as atypical the EIIIB exon and its flanking intron sequences, both in vivo and in vitro. We also report that alterations in the ionic conditions of the in vitro splicing reaction can promote the initiation of EIIIB exon inclusion, as reflected by the formation of intermediate and product RNAs related to the removal of the intron upstream of EIIIB. Processing of this intron correlates with the formation of complexes resembling intermediates in spliceosome assembly. The branch sites involved in this alternative processing pathway are rather distant from the EIIIB 3' splice site, and lie within a region which is well conserved in the fibronectin genes of other species. Thus, the intron upstream of EIIIB shows singular structure and behavior which probably have a bearing on the regulated alternative splicing of this exon. Images PMID:2377454

  5. Adhesion and migration of avian neural crest cells on fibronectin require the cooperating activities of multiple integrins of the (beta)1 and (beta)3 families.

    PubMed

    Testaz, S; Delannet, M; Duband, J

    1999-12-01

    Based on genetic, functional and histological studies, the extracellular matrix molecule fibronectin has been proposed to play a key role in the migration of neural crest cells in the vertebrate embryo. In the present study, we have analyzed in vitro the repertoire and function of integrin receptors involved in the adhesive and locomotory responses of avian truncal neural crest cells to fibronectin. Immunoprecipitation experiments showed that neural crest cells express multiple integrins, namely (alpha)3(beta)1, (alpha)4(beta)1, (alpha)5(beta)1, (alpha)8(beta)1, (alpha)v(beta)1, (alpha)v(beta)3 and a (beta)8 integrin, as potential fibronectin receptors, and flow cytometry analyses revealed no major heterogeneity among the cell population for expression of integrin subunits. In addition, the integrin repertoire expressed by neural crest cells was found not to change dramatically during migration. At the cellular level, only (alpha)v(beta)1 and (alpha)v(beta)3 were concentrated in focal adhesion sites in connection with the actin microfilaments, whereas the other integrins were predominantly diffuse over the cell surface. In inhibition assays with function-perturbing antibodies, it appeared that complete abolition of cell spreading and migration could be achieved only by blocking multiple integrins of the (beta)1 and (beta)3 families, suggesting possible functional compensations between different integrins. In addition, these studies provided evidence for functional partitioning of integrins in cell adhesion and migration. While spreading was essentially mediated by (alpha)v(beta)1 and (alpha)8(beta)1, migration involved primarily (alpha)4(beta)1, (alpha)v(beta)3 and (alpha)8(beta)1 and, more indirectly, (alpha)3(beta)1. (alpha)5(beta)1 and the (beta)8 integrin were not found to play any major role in either adhesion or migration. Finally, consistent with the results of inhibition experiments, recruitment of (alpha)4(beta)1 and (alpha)v(beta)3, individually or in

  6. Impaired Driving

    MedlinePlus

    ... Risk Factors BAC Effects Prevention Additional Resources How big is the problem? In 2014, 9,967 people ... Driving: A Threat to Everyone (October 2011) Additional Data Drunk Driving State Data and Maps Motor Vehicle ...

  7. Drugged Driving

    MedlinePlus

    ... Infographics » Drugged Driving Drugged Driving Email Facebook Twitter Text Description of Infographic Top Right Figure : In 2009, ... crash than those who don't smoke. Bottom Text: Develop Social Strategies Offer to be a designated ...

  8. Fibronectin receptor functions in embryonic cells deficient in alpha 5 beta 1 integrin can be replaced by alpha V integrins.

    PubMed Central

    Yang, J T; Hynes, R O

    1996-01-01

    alpha 5 beta 1 integrin mediates cell adhesion to extracellular matrix by interacting with fibronectin (FN). Mouse lines carrying null mutations in genes encoding either the alpha 5 integrin subunit or FN have been generated previously. Both mutations are embryonic lethal with overlapping defects, but the defects of alpha 5-null embryos are less severe. Primary embryonic cells lacking alpha 5 beta 1 are able to adhere to FN, form focal contacts, migrate on FN, and assemble FN matrix. These results suggest the involvement of (an)other FN receptors(s). In this study, we examined functions of alpha 4 beta 1 and alpha V integrins in embryonic cells lacking alpha 5 beta 1. Our analysis of cells lacking both alpha 4 beta 1 and alpha 5 beta 1 showed that alpha 4 beta 1 is also not required for these FN-dependent functions. Using alpha V-specific blocking reagents, we showed that alpha V integrins are required for alpha 5-null cells, but not wild-type cells, to adhere and spread on FN. Our data also showed that, although the expression levels of alpha V integrins on the wild-type and alpha 5-null cells are similar, there is an increase in recruitment of alpha V integrins into focal contacts in alpha 5-null cells plated on FN, indicating that alpha V integrins can compensate functionally for the loss of alpha 5 beta 1 in focal contacts of alpha 5-null cells. Finally, our data suggested possible roles for alpha V integrins in replacing the role of alpha 5 beta 1 in FN matrix assembly in vitro and in FN-dependent embryonic functions in vivo. Images PMID:8930896

  9. Plakoglobin regulates cell motility through Rho- and fibronectin-dependent Src signaling

    PubMed Central

    Todorović, Viktor; Desai, Bhushan V.; Patterson, Melanie J. Schroeder; Amargo, Evangeline V.; Dubash, Adi D.; Yin, Taofei; Jones, Jonathan C. R.; Green, Kathleen J.

    2010-01-01

    We previously showed that the cell–cell junction protein plakoglobin (PG) not only suppresses motility of keratinocytes in contact with each other, but also, unexpectedly, of single cells. Here we show that PG deficiency results in extracellular matrix (ECM)-dependent disruption of mature focal adhesions and cortical actin organization. Plating PG−/− cells onto ECM deposited by PG+/− cells partially restored normal cell morphology and inhibited PG−/− cell motility. In over 70 adhesion molecules whose expression we previously showed to be altered in PG−/− cells, a substantial decrease in fibronectin (FN) in PG−/− cells stood out. Re-introduction of PG into PG−/− cells restored FN expression, and keratinocyte motility was reversed by plating PG−/− cells onto FN. Somewhat surprisingly, based on previously reported roles for PG in regulating gene transcription, PG-null cells exhibited an increase, not a decrease, in FN promoter activity. Instead, PG was required for maintenance of FN mRNA stability. PG−/− cells exhibited an increase in activated Src, one of the kinases controlled by FN, a phenotype reversed by plating PG−/− cells on ECM deposited by PG+/− keratinocytes. PG−/− cells also exhibited Src-independent activation of the small GTPases Rac1 and RhoA. Both Src and RhoA inhibition attenuated PG−/− keratinocyte motility. We propose a novel role for PG in regulating cell motility through distinct ECM–Src and RhoGTPase-dependent pathways, influenced in part by PG-dependent regulation of FN mRNA stability. PMID:20876660

  10. Combinatorial Fibronectin and Laminin Signaling Promote Highly Efficient Cardiac Differentiation of Human Embryonic Stem Cells

    PubMed Central

    Sa, Silin; Wong, Lian

    2014-01-01

    Abstract Cardiomyocytes (CMs) differentiated from human embryonic stem cells (hESCs) are a promising and potentially unlimited cell source for myocardial repair and regeneration. Recently, multiple methodologies—primarily based on the optimization of growth factors—have been described for efficient cardiac differentiation of hESCs. However, the role of extracellular matrix (ECM) signaling in CM differentiation has not yet been explored fully. This study examined the role of ECM signaling in the efficient generation of CMs from both H7 and H9 ESCs. The hESCs were differentiated on ECM substrates composed of a range of fibronectin (FN) and laminin (LN) ratios and gelatin and evaluated by the fluorescence activated cell scanning (FACS) analysis on day 14. Of the ECM substrates examined, the 70:30 FN:LN reproducibly generated the greatest numbers of CMs from both hESC lines. Moreover, the LN receptor integrin β4 (ITGB4) and FN receptor integrin β5 (ITGB5) genes, jointly with increased phosphorylated focal adhension kinase and phosphorylated extracellular signal-regulated kinases (p-ERKs), were up-regulated over 13-fold in H7 and H9 cultured on 70:30 FN:LN compared with gelatin. Blocking studies confirmed the role of all these molecules in CM specification, suggesting that the 70:30 FN:LN ECM promotes highly efficient differentiation of CMs through the integrin-mediated MEK/ERK signaling pathway. Lastly, the data suggest that FN:LN-induced signaling utilizes direct cell-to-cell signaling from distinct ITGB4+ and ITGB5+ cells. PMID:25126479

  11. WISE focal plane module lessons learned in light of success

    NASA Astrophysics Data System (ADS)

    Masterjohn, S.; Hogue, H.; Muzilla, M.; Rector, S.; Mattson, R.

    2010-08-01

    DRS Sensors & Targeting Systems, under contract to the Space Dynamics Laboratory of Utah State University, provided the focal plane detector system for NASA's Wide-field Infrared Survey Explorer (WISE). The focal plane detector system consists of two mercury cadmium telluride (MCT) focal plane module assemblies (FPMAs), two arsenic doped silicon (Si:As) Blocked Impurity Band (BIB) FPMAs, electronics to drive the FPMAs and report digital data from them, and the cryogenic and ambient temperature cabling that connect the FPMAs and electronics. The WISE Satellite was launched in late 2009 and has been a very rewarding success. In light of the recent success on orbit, there were many challenges and hurdles the DRS team had to overcome in order to guarantee the ultimate success of the instrument. This report highlights a few of the challenges that the team overcame in hopes that the information can be made available to the astronomy community for future use.

  12. Statistical Earthquake Focal Mechanism Forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Y. Y.; Jackson, D. D.

    2013-12-01

    The new whole Earth focal mechanism forecast, based on the GCMT catalog, has been created. In the present forecast, the sum of normalized seismic moment tensors within 1000 km radius is calculated and the P- and T-axes for the focal mechanism are evaluated on the basis of the sum. Simultaneously we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms. This average angle shows tectonic complexity of a region and indicates the accuracy of the prediction. The method was originally proposed by Kagan and Jackson (1994, JGR). Recent interest by CSEP and GEM has motivated some improvements, particularly to extend the previous forecast to polar and near-polar regions. The major problem in extending the forecast is the focal mechanism calculation on a spherical surface. In the previous forecast as our average focal mechanism was computed, it was assumed that longitude lines are approximately parallel within 1000 km radius. This is largely accurate in the equatorial and near-equatorial areas. However, when one approaches the 75 degree latitude, the longitude lines are no longer parallel: the bearing (azimuthal) difference at points separated by 1000 km reach about 35 degrees. In most situations a forecast point where we calculate an average focal mechanism is surrounded by earthquakes, so a bias should not be strong due to the difference effect cancellation. But if we move into polar regions, the bearing difference could approach 180 degrees. In a modified program focal mechanisms have been projected on a plane tangent to a sphere at a forecast point. New longitude axes which are parallel in the tangent plane are corrected for the bearing difference. A comparison with the old 75S-75N forecast shows that in equatorial regions the forecasted focal mechanisms are almost the same, and the difference in the forecasted focal mechanisms rotation angle is close to zero. However, though the forecasted focal mechanisms are similar

  13. Fibronectin tetrapeptide is target for syphilis spirochete cytadherence

    SciTech Connect

    Thomas, D.D.; Baseman, J.B.; Alderete, J.F.

    1985-11-01

    The syphilis bacterium, Treponema pallidum, parasitizes host cells through recognition of fibronectin (Fn) on cell surfaces. The active site of the Fn molecule has been identified as a four-amino acid sequence, arg-gly-asp-ser (RGDS), located on each monomer of the cell-binding domain. The synthetic heptapeptide gly-arg-gly-asp-ser-pro-cys (GRGDSPC), with the active site sequence RGDS, specifically competed with SVI-labeled cell-binding domain acquisition by T. pallidum. Additionally, the same heptapeptide with the RGDS sequence diminished treponemal attachment to HEp-2 and HT1080 cell monolayers. Related heptapeptides altered in one key amino acid within the RGDS sequence failed to inhibit Fn cell-binding domain acquisition or parasitism of host cells by T. pallidum. The data support the view that T. pallidum cytadherence of host cells is through recognition of the RGDS sequence also important for eukaryotic cell-Fn binding.

  14. Fibronectin in the ruptured human Achilles tendon and its paratenon. An immunoperoxidase study.

    PubMed

    Lehto, M; Jozsa, L; Kvist, M; Järvinen, M; Balint, B J; Reffy, A

    1990-01-01

    The purpose of the present study was to examine the role and distribution of fibronectin--a major connective tissue protein--in normal and ruptured Achilles tendon and its paratenon using peroxidase antiperoxidase (PAP) method and conventional histology. Samples were taken intraoperatively 6 to 48 hours after rupture from 30 patients, and 4 male cadavers served as controls. In controls fibronectin could not be detected in the tendinous connective tissue or in the areolar tissue of the paratenon. In the ruptured tendons fibronectin was detected around the tenocytes and in the collagen fibres in the necrotic and mucinous degenerated areas, but also in the macroscopically healthy areas of the tendon. In the oedematous paratenon vascular walls were rich in fibronectin and fat cells were outlined by fibronectin. Areas of homogenous deposition of fibronectin were also frequently seen in the paratenon. A vast amount of fibronectin was observed also at the site of rupture. The present results indicate that there are striking changes in the composition of connective tissue in degenerated tendon and paratenon. These changes seem to have increased susceptibility of the tendon to rupture. PMID:2201247

  15. Role of Fibronectin in the Adhesion of Acinetobacter baumannii to Host Cells

    PubMed Central

    Smani, Younes; McConnell, Michael J.; Pachón, Jerónimo

    2012-01-01

    Adhesion to host cells is an initial and important step in Acinetobacter baumannii pathogenesis. However, there is relatively little information on the mechanisms by which A. baumannii binds to and interacts with host cells. Adherence to extracellular matrix proteins, such as fibronectin, affords pathogens with a mechanism to invade epithelial cells. Here, we found that A. baumannii adheres more avidly to immobilized fibronectin than to control protein. Free fibronectin used as a competitor resulted in dose-dependent decreased binding of A. baumannii to fibronectin. Three outer membrane preparations (OMPs) were identified as fibronectin binding proteins (FBPs): OMPA, TonB-dependent copper receptor, and 34 kDa OMP. Moreover, we demonstrated that fibronectin inhibition and neutralization by specific antibody prevented significantly the adhesion of A. baumannii to human lung epithelial cells (A549 cells). Similarly, A. baumannii OMPA neutralization by specific antibody decreased significantly the adhesion of A. baumannii to A549 cells. These data indicate that FBPs are key adhesins that mediate binding of A. baumannii to human lung epithelial cells through interaction with fibronectin on the surface of these host cells. PMID:22514602

  16. A fibronectin receptor on Candida albicans mediates adherence of the fungus to extracellular matrix

    SciTech Connect

    Klotz, S.A.; Smith, R.L. )

    1991-03-01

    Binding of fibronectin, an extracellular matrix (ECM) protein, to Candida albicans was measured, and adherence of the fungus to immobilized ECM proteins, fibronectin, laminin, types I and IV collagen, and subendothelial ECM was studied. 125I-labeled fibronectin was inhibited from binding to the fungus by unlabeled human plasma fibronectin and by Arg-Gly-Asp (RGD), Gly-Arg-Gly-Glu-Ser-Pro (GRGESP), and Gly-Arg-Gly-Asp-Thr-Pro (GRGDTP), but binding was not inhibited by Gly-Arg-Gly-Asp-Ser-Pro. Soluble fibronectin, RGD, GRGESP, and GRGDTP also inhibited fungal adherence to the individual immobilized ECM proteins in a complex pattern, but only soluble fibronectin (10(-7) M) inhibited fungal adherence to subendothelial ECM. Thus, C. albicans possesses at least one type of cell surface receptor for binding soluble fibronectin that can be inhibited with peptides. This receptor apparently is used to bind the fungus to immobilized ECM proteins and to subendothelial ECM and may play a role in the initiation of disseminated disease by bloodborne fungi by providing for adherence of the microorganisms to ECM proteins.

  17. Fibronectin-Containing Extracellular Vesicles Protect Melanocytes against Ultraviolet Radiation-Induced Cytotoxicity.

    PubMed

    Bin, Bum-Ho; Kim, Dae-Kyum; Kim, Nan-Hyung; Choi, Eun-Jeong; Bhin, Jinhyuk; Kim, Sung Tae; Gho, Yong Song; Lee, Ai-Young; Lee, Tae Ryong; Cho, Eun-Gyung

    2016-05-01

    Skin melanocytes are activated by exposure to UV radiation to secrete melanin-containing melanosomes to protect the skin from UV-induced damage. Despite the continuous renewal of the epidermis, the turnover rate of melanocytes is very slow, and they survive for long periods. However, the mechanisms underlying the survival of melanocytes exposed to UV radiation are not known. Here, we investigated the role of melanocyte-derived extracellular vesicles in melanocyte survival. Network analysis of the melanocyte extracellular vesicle proteome identified the extracellular matrix component fibronectin at a central node, and the release of fibronectin-containing extracellular vesicles was increased after exposure of melanocytes to UVB radiation. Using an anti-fibronectin neutralizing antibody and specific inhibitors of extracellular vesicle secretion, we demonstrated that extracellular vesicles enriched in fibronectin were involved in melanocyte survival after UVB radiation. Furthermore, we observed that in the hyperpigmented lesions of patients with melasma, the extracellular space around melanocytes contained more fibronectin compared with normal skin, suggesting that fibronectin is involved in maintaining melanocytes in pathological conditions. Collectively, our findings suggest that melanocytes secrete fibronectin-containing extracellular vesicles to increase their survival after UVB radiation. These data provide important insight into how constantly stimulated melanocytes can be maintained in pathological conditions such as melasma. PMID:26854492

  18. Plasma fibronectin promotes lung metastasis by contributions to fibrin clots and tumor cell invasion.

    PubMed

    Malik, Gunjan; Knowles, Lynn M; Dhir, Rajiv; Xu, Shuping; Yang, Shuting; Ruoslahti, Erkki; Pilch, Jan

    2010-06-01

    The attachment of circulating tumor cells to the blood vessels of distant organs is an important step in metastasis. We show here that experimental lung metastasis by two cell lines, B16F1 melanoma and 3LL lung carcinoma, is greatly reduced in transgenic mice that lack plasma fibronectin. This multifunctional adhesive glycoprotein becomes cross-linked to fibrin during clotting. Here, we report that eliminating plasma fibronectin from the blood circulation reverses the prometastatic effects of blood clotting and tumor cell integrin alphavbeta3. In vitro studies showed that fibrin-fibronectin complexes, but not purified fibrin, supported tumor cell attachment and invasion. These functions correlate with the ability of fibrin-fibronectin complexes to induce the activation of integrin alphavbeta3. Our findings reveal an important contribution of plasma fibronectin in lung metastasis. Furthermore, they suggest that the previously noted effects of blood clotting on lung metastasis might be mediated in part by a fibronectin-alphavbeta3 integrin axis, in which plasma fibronectin has to be incorporated into the blood clot. PMID:20501851

  19. Conformational changes of fibronectin induced by polystyrene derivatives with a heparin-like function

    SciTech Connect

    Stanislawski, L. ); Serne, H.; Jozefowicz, M. ); Stanislawski, M. )

    1993-05-01

    It was previously reported that polystyrene substituted with the sulfonate group, PSSO[sub 3], which has anticoagulant heparin-like properties, and then coated with fibronectin supports the growth of human umbilical vein endothelial cells. On the other hand, polystyrene substituted with the amino acid sulfamide group, PSSO[sub 2]-Asp, which has a higher anticoagulant activity, and then coated with fibronectin no longer supported the growth of endothelial cells. The authors report here that, while the affinity of fibronectin to either polymer is of the same order of magnitude, fibronectin is adsorbed onto the PSSO[sub 2]-Asp polymer in a different conformation compared to the PSSO[sub 3] polymer. This was shown by a higher binding of polyclonal antifibronectin antibodies to fibronectin-coated PSSO[sub 2]-Asp polymer, and by a decreased susceptibility of the coated fibronectin to proteolysis by thermolysin. This study provides evidence that a solid phase substrate with a strong heparin-like function may influence the conformation and biological properties of fibronectin.

  20. Defects in MAP1S-mediated autophagy turnover of fibronectin cause renal fibrosis

    PubMed Central

    He, Yongzhong; Li, Xun; Zhao, Haibo; Su, Zhengming; Jiang, Xianhan; Li, Wenjiao; Zou, Jing; Chen, Qi; Liu, Leyuan

    2016-01-01

    Excessive deposition of extracellular matrix proteins in renal tissues causes renal fibrosis and renal function failure. Mammalian cells primarily use the autophagy-lysosome system to degrade misfolded/aggregated proteins and dysfunctional organelles. MAP1S is an autophagy activator and promotes the biogenesis and degradation of autophagosomes. Previously, we reported that MAP1S suppresses hepatocellular carcinogenesis in a mouse model and predicts a better prognosis in patients suffering from clear cell renal cell carcinomas. Furthermore, we have characterized that MAP1S enhances the turnover of fibronectin, and mice overexpressing LC3 but with MAP1S deleted accumulate fibronectin and develop liver fibrosis because of the synergistic impact of LC3-induced over-synthesis of fibronectin and MAP1S depletion-caused impairment of fibronectin degradation. Here we show that a suppression of MAP1S in renal cells caused an impairment of autophagy clearance of fibronectin and an activation of pyroptosis. Depletion of MAP1S in mice leads to an accumulation of fibrosis-related proteins and the development of renal fibrosis in aged mice. The levels of MAP1S were dramatically reduced and levels of fibronectin were greatly elevated in renal fibrotic tissues from patients diagnosed as renal atrophy and renal failure. Therefore, MAP1S deficiency may cause the accumulation of fibronectin and the development of renal fibrosis. PMID:27236336

  1. Design of large aperture focal plane shutter

    NASA Astrophysics Data System (ADS)

    Hu, Jia-wen; Ma, Wen-li; Huang, Jin-long

    2012-09-01

    To satisfy the requirement of large telescope, a large aperture focal plane shutter with aperture size of φ200mm was researched and designed to realize, which could be started and stopped in a relative short time with precise position, and also the blades could open and close at the same time at any orientation. Timing-belts and stepper motors were adopted as the drive mechanism. Velocity and position of the stepper motors were controlled by the PWM pulse generated by DSP. Exponential curve is applied to control the velocity of the stepper motors to make the shutter start and stop in a short time. The closing/open time of shutter is 0.2s, which meets the performance requirements of large telescope properly.

  2. Drug discovery in focal and segmental glomerulosclerosis.

    PubMed

    Pullen, Nick; Fornoni, Alessia

    2016-06-01

    Despite the high medical burden experienced by patients with focal segmental glomerulosclerosis, the etiology of the condition remains largely unknown. Focal segmental glomerulosclerosis is highly heterogeneous in clinical and morphologic manifestations. While this presents challenges for the development of new treatments, research investments over the last 2 decades have yielded a surfeit of potential avenues for therapeutic intervention. The development of many of those ideas and concepts into new therapies, however, has been very disappointing. Here, we describe some of the factors that have potentially contributed to the poor translational performance from this research investment, including the confidence we ascribe to a target, the conduct of experimental studies, and the availability of selective reagents to test hypotheses. We will discuss the significance of genetic and systems traits as well as other methods for reducing bias. We will analyze the limitations of a successful drug development. We will use specific examples hoping that these will guide a consensus for investment and drive greater translational quality. We hope that this substrate will serve to exemplify the tremendous opportunity for intervention as well as facilitate greater collaborative effort between industry, academia, and private foundations in promoting appropriate validation of these targets. Only then will we have achieved our goal for curative therapies for this devastating disease. PMID:27165834

  3. The Focal Surface of the JEM-EUSO Instrument

    SciTech Connect

    Kawasaki, Y.; Casolino, M.; Gorodetzky, P.; Santangelo, A.; Ricci, M.; Kajino, F.; Ebisuzaki, T.

    2011-09-22

    The Extreme Universe Space Observatory on JEM/EF (JEM-EUSO) is a space mission to study extremely high-energy cosmic rays. The JEM-EUSO instrument is a wide-angle refractive telescope in the near-ultraviolet wavelength region which will be mounted to the International Space Station. Its goal is to measure time-resolved fluorescence images of extensive air showers in the atmosphere. In this paper we describe in detail the main features and technological aspects of the focal surface of the instrument. The JEM-EUSO focal surface is a spherically curved surface, with an area of about 4.5m{sup 2}. The focal surface detector is made of more than 5,000 multi-anode photomultipliers (MAPMTs). Current baseline is Hamamatsu R11265-03-M64. The approach to the focal surface detector is highly modular. Photo-Detector-Modules (PDM) are the basic units that drive the mechanical structure and data acquisition. Each PDM consists of 9 Elementary Cells (ECs). The EC, which is the basic unit of the MAPMT support structure and of the front-end electronics, contains 4 units of MAPMTs. In total, about 1,200 ECs or about 150 PDMs are arranged on the whole of the focal surface of JEM-EUSO.

  4. Fibronectin binding by Streptococcus milleri group strains and partial characterisation of the fibronectin receptor of Streptococcus anginosus F4.

    PubMed

    Willcox, M D; Loo, C Y; Harty, D W; Knox, K W

    1995-09-01

    The Streptococcus milleri group were shown to bind fibronectin (Fn) to their cell-surface and this binding increased the adhesion of cells to hydroxyapatite. The binding of Fn to Streptococcus anginosus F4 was studied in more detail. Fn binding to bacterial cells increased the association of the bacteria with the polymorphonuclear leukocytes obtained from the peritoneal cavity of rats but did not increase killing of the bacteria. The cell-surface receptor was a protein of M(r) 14,000 which was released from cells after mutanolysin digestion. The binding was specific, with cells having a maximum number of binding sites per cell of 770. Electron microscopy, using gold-labelled Fn, localised the receptor to areas between daughter cells. PMID:8559042

  5. Pile Driving

    NASA Technical Reports Server (NTRS)

    1987-01-01

    Machine-oriented structural engineering firm TERA, Inc. is engaged in a project to evaluate the reliability of offshore pile driving prediction methods to eventually predict the best pile driving technique for each new offshore oil platform. Phase I Pile driving records of 48 offshore platforms including such information as blow counts, soil composition and pertinent construction details were digitized. In Phase II, pile driving records were statistically compared with current methods of prediction. Result was development of modular software, the CRIPS80 Software Design Analyzer System, that companies can use to evaluate other prediction procedures or other data bases.

  6. Precise Measurement of Effective Focal Length

    NASA Technical Reports Server (NTRS)

    Wise, T. D.; Young, J. B.

    1983-01-01

    Computerized instrument measures effective focal lengths to 0.01 percent accuracy. Laser interferometers measure mirror angle and stage coordinate y in instrument for accurate measurment of focal properties of optical systems. Operates under computer control to measure effective focal length, focal surface shape, modulation transfer function, and astigmatism.

  7. Sex prevalence of focal dystonias.

    PubMed Central

    Soland, V L; Bhatia, K P; Marsden, C D

    1996-01-01

    The sex prevalence of idiopathic focal dystonia is reported from a data base review of all patients seen at the National Hospital of Neurology, Queen Square and King's College, London up to 1993. There was a higher prevalence of females to males in all categories of focal dystonia involving the craniocervical region. The female to male ratio for cranial dystonia was 1.92:1 (P < 0.01) and 1.6:1 (P < 0.001) for spasmodic torticollis. On the other hand, twice as many men than women had writer's cramp (M:F = 2.0:1, P < 0.01). At present, there is no clear explanation to account for this differences in the sex prevalence of different types of focal dystonia. PMID:8708656

  8. Continuously variable focal length lens

    DOEpatents

    Adams, Bernhard W; Chollet, Matthieu C

    2013-12-17

    A material preferably in crystal form having a low atomic number such as beryllium (Z=4) provides for the focusing of x-rays in a continuously variable manner. The material is provided with plural spaced curvilinear, optically matched slots and/or recesses through which an x-ray beam is directed. The focal length of the material may be decreased or increased by increasing or decreasing, respectively, the number of slots (or recesses) through which the x-ray beam is directed, while fine tuning of the focal length is accomplished by rotation of the material so as to change the path length of the x-ray beam through the aligned cylindrical slows. X-ray analysis of a fixed point in a solid material may be performed by scanning the energy of the x-ray beam while rotating the material to maintain the beam's focal point at a fixed point in the specimen undergoing analysis.

  9. Fibronectin is a binding partner for the myelin-associated glycoprotein (siglec-4a).

    PubMed

    Strenge, K; Brossmer, R; Ihrig, P; Schauer, R; Kelm, S

    2001-06-22

    The myelin-associated glycoprotein (MAG) mediates cell-cell interactions between myelinating glial cells and neurons. Here we describe the extracellular matrix glycoprotein fibronectin as a binding partner of MAG. It has been identified by affinity precipitation with MAG-Fc from NG108-15 cells and by microsequencing of two peptides derived from a 210-kDa protein band. Western blot analysis showed that fibronectin is also present in MAG binding partners isolated from N(2)A (murine neuroblastoma) cells, rat brain and rat spinal cord. Different fibronectin isoforms have been isolated from brains of young and adult rats, indicating that the expression of MAG binding fibronectin changes during development. PMID:11423128

  10. Anastellin, an FN3 Fragment with Fibronectin Polymerization Activity, Resembles Amyloid Fibril Precursors

    SciTech Connect

    Briknarova, Klara; Akermann, Maria; Hoyt, David W. ); Ruoslahti, Erkki; Ely, Kathryn R.

    2003-08-01

    Anastellin is a carboxy-terminal fragment of the 1st FN3 domain from human fibronectin. It is capable of polymerizing fibronectin in vitro, and it displays anti-tumor, antimetastatic and anti-angiogenic properties in vivo. We have determined the structure of anastellin using nuclear magnetic resonance spectroscopy and identified residues critical for its activity. Anastellin exhibits dynamic fluctuations and conformational exchange in solution. Its overall topology is very similar to the corresponding region of full-length FN3 domains. However, its hydrophobic core becomes solvent accessible and some of its -strands lose their protection against hydrogen bonding to -strands from other molecules. These features seem to be relevant for the fibronectin polymerization activity of anastellin and resemble the characteristics of amyloid fibril precursors. We suggest that this analogy is not random and may reflect similarities between fibronectin and amyloid fibril formation.

  11. Interaction between Fibronectin and β1 Integrin Is Essential for Tooth Development

    PubMed Central

    Yamada, Aya; Yuasa, Kenji; Yoshizaki, Keigo; Iwamoto, Tsutomu; Saito, Masahiro; Nakamura, Takashi; Fukumoto, Satoshi

    2015-01-01

    The dental epithelium and extracellular matrix interact to ensure that cell growth and differentiation lead to the formation of teeth of appropriate size and quality. To determine the role of fibronectin in differentiation of the dental epithelium and tooth formation, we analyzed its expression in developing incisors. Fibronectin mRNA was expressed during the presecretory stage in developing dental epithelium, decreased in the secretory and early maturation stages, and then reappeared during the late maturation stage. The binding of dental epithelial cells derived from postnatal day-1 molars to a fibronectin-coated dish was inhibited by the RGD but not RAD peptide, and by a β1 integrin-neutralizing antibody, suggesting that fibronectin-β1 integrin interactions contribute to dental epithelial-cell binding. Because fibronectin and β1 integrin are highly expressed in the dental mesenchyme, it is difficult to determine precisely how their interactions influence dental epithelial differentiation in vivo. Therefore, we analyzed β1 integrin conditional knockout mice (Intβ1lox-/lox-/K14-Cre) and found that they exhibited partial enamel hypoplasia, and delayed eruption of molars and differentiation of ameloblasts, but not of odontoblasts. Furthermore, a cyst-like structure was observed during late ameloblast maturation. Dental epithelial cells from knockout mice did not bind to fibronectin, and induction of ameloblastin expression in these cells by neurotrophic factor-4 was inhibited by treatment with RGD peptide or a fibronectin siRNA, suggesting that the epithelial interaction between fibronectin and β1 integrin is important for ameloblast differentiation and enamel formation. PMID:25830530

  12. Renal proximal tubular cell fibronectin accumulation in response to glucose is polyol pathway dependent

    PubMed

    Morrisey; Steadman; Williams; Phillips

    1999-06-01

    Thickening and reduplication of the tubular basement membrane has been reported as an early event in diabetic nephropathy. In the current study we have examined the polar requirements of proximal tubular cells for the D-glucose stimulated accumulation of fibronectin. We also examined the mechanism by which glucose led to accumulation of fibronectin, with particular emphasis on the polyol pathway. Incubation of confluent monolayers of LLC-PK1 cells grown on tissue culture inserts with 25 mM D-glucose on either their apical or basolateral aspect, led to fibronectin accumulation in the basolateral compartment. This reached statistical significance 24 h following apical addition of glucose (2.7 fold increase compared to 5 mM D-glucose, p = 0.007, n = 6), and 12 h after the basolateral addition of glucose (2.54 fold increase compared to 5 mM D-glucose, p = 0.02, n = 6). The increase in fibronectin concentration in response to glucose was inhibited by the aldose reductase inhibitor sorbinil. At a dose of 100&mgr;M sorbinil there was 59% inhibition of fibronectin accumulation in response to glucose, 48 h after the addition of the inhibitor (4.76 +/- 1.4 vs 11.53 +/- 1.41, mean +/- SD, p = 0.01, n = 3). Exposure of cells to glucose at either their apical or basolateral aspect lead to accumulation of intracellular glucose and polyol pathway activation, as assessed by sorbitol accumulation. Accumulation of intracellular glucose and hence subsequent polyol pathway activation occurred independently of transport of glucose by either apical sodium linked glucose transporter (SLGT) or basolateral GLUT 1. The data demonstrate that fibronectin generation in response to glucose was non-polar in terms application of glucose, but polar in terms of fibronectin accumulation. Furthermore modulation of fibronectin was mediated by polyol pathway activation, and more specifically related to the metabolism of sorbitol to fructose. PMID:10354307

  13. Effects of class I heparin binding growth factor and fibronectin on platelet adhesion and aggregation

    SciTech Connect

    Greisler, H.P.; Klosak, J.J.; Steinam, S.J.; Lam, T.M.; Burgess, W.H.; Kim, D.U. )

    1990-05-01

    Fibronectin and heparin binding growth factor-type 1 have been affixed to vascular graft surfaces to enhance the attachment and the proliferation of transplanted endothelial cells, respectively. The current study examines the effect of fibronectin and heparin binding growth factor-type 1 on platelet adhesion and activation in vivo and on platelet aggregation in vitro. Expanded polytetrafluoroethylene prostheses (5 cm x 4 mm internal diameter) were treated either with fibronectin (n = 9), fibronectin/heparin/heparin binding growth factor-type 1/heparin (n = 12), or neither (n = 13) and were interposed into canine aortoiliac systems bilaterally. Autogenous radiolabeled (Indium 111 oxine, 650 microCi) platelets were injected intravenously before reestablishment of circulation. Perfusion was maintained for 30 minutes, and prostheses were removed with segments of native aorta and distal iliac arteries bilaterally. Specimens were examined for thrombus-free surface area, by gamma well counting for adherent radiolabeled platelets, and by light microscopy and transmission and scanning electron microscopic techniques. Results showed that both the fibronectin and fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained significantly greater numbers of platelets and adherent radioactivity than did control graft segments when normalized to their ipsilateral iliac arteries. Fibronectin/heparin/heparin binding growth factor-type 1/heparin pretreated prostheses contained 27 +/- 16 times more radioactivity per square millimeter than ipsilateral iliac arteries, fibronectin pretreated prostheses had 13 +/- 8 times more radioactivity per square millimeter than ipsilateral iliac arteries, and untreated expanded polytetrafluoroethylene had 4 +/- 3 times more radioactivity per square millimeter than ipsilateral iliac arteries.

  14. α-Actinin-4 Enhances Colorectal Cancer Cell Invasion by Suppressing Focal Adhesion Maturation

    PubMed Central

    Yamada, Tesshi; Takenawa, Tadaomi

    2015-01-01

    α-Actinins (ACTNs) are known to crosslink actin filaments at focal adhesions in migrating cells. Among the four isoforms of mammalian ACTNs, ACTN1 and ACTN4 are ubiquitously expressed. Recently, ACTN4 was reported to enhance cancer cell motility, invasion, and metastasis. However, the mechanism by which ACTN4 drives these malignant phenotypes remains unclear. Here, we show that ACTN4, but not ACTN1, induces the formation of immature focal adhesions in DLD-1 cells, leading to the rapid turnover of focal adhesions. Interestingly, zyxin (ZYX) assembly to focal adhesions was markedly decreased in ACTN4-expressing DLD-1 cells, while the recruitment of paxillin (PAX) occurred normally. On the other hand, in ACTN1-expressing DLD-1 cells, PAX and ZYX were normally recruited to focal adhesions, suggesting that ACTN4 specifically impairs focal adhesion maturation by inhibiting the recruitment of ZYX to focal complexes. Using purified recombinant proteins, we found that ZYX binding to ACTN4 was defective under conditions where ZYX binding to ACTN1 was observed. Furthermore, Matrigel invasion of SW480 cells that express high endogenous levels of ACTN4 protein was inhibited by ectopic expression of ACTN1. Altogether, our results suggest that ZYX defective binding to ACTN4, which occupies focal adhesions instead of ACTN1, induces the formation of immature focal adhesions, resulting in the enhancement of cell motility and invasion. PMID:25860875

  15. Transforming growth factor beta increases cell surface binding and assembly of exogenous (plasma) fibronectin by normal human fibroblasts.

    PubMed Central

    Allen-Hoffmann, B L; Crankshaw, C L; Mosher, D F

    1988-01-01

    Transforming growth factor beta (TGF-beta) enhances the cell surface binding of 125I-fibronectin by cultured human fibroblasts. The effect of TGF-beta on cell surface binding was maximal after 2 h of exposure to TFG-beta and did not require epidermal growth factor or protein synthesis. The enhancement was dose dependent and was found with the 125I-labeled 70-kilodalton amino-terminal fragment of fibronectin as well as with 125I-fibronectin. Treatment of cultures with TGF-beta for 6 h resulted in a threefold increase in the estimated number of fibronectin binding sites. The increase in number of binding sites was accompanied by an increased accumulation of labeled fibronectin in detergent-insoluble extracellular matrix. The effect of TGF-beta was biphasic; after 6 h of exposure, less labeled fibronectin bound to treated cultures than to control cultures. Exposure of cells to TGF-beta for greater than 6 h caused a two- to threefold increase in the accumulation of cellular fibronectin in culture medium as detected by a quantitative enzyme-linked immunosorbent assay. The second phase of the biphasic effect and the increase in soluble cellular fibronectin were blocked by cycloheximide. Immunofluorescence staining of fibroblast cultures with antifibronectin revealed that TGF-beta caused a striking increase in fibronectin fibrils. The 70-kilodalton amino-terminal fragment of fibronectin, which blocks incorporation of fibronectin into extracellular matrix, blocked anchorage-independent growth of NRK-49F cells in the presence of epidermal growth factor. Our results show that an increase in the binding and rate of assembly of exogenous fibronectin is an early event preceding the increase in expression of extracellular matrix proteins. Such an early increase in cell surface binding of exogenous fibronectin may be a mechanism whereby TGF-beta can modify extracellular matrix characteristics rapidly after tissue injury or during embryonic morphogenesis. Images PMID:3054513

  16. Cryptic activity within the Type III1 domain of fibronectin regulates tissue inflammation and angiogenesis

    PubMed Central

    Cho, Christina; Kelsh-Lasher, Rhiannon; Ambesi, Anthony; McKeown-Longo, Paula J.

    2016-01-01

    The fibronectin matrix provides mechanical and biochemical information to regulate homeostatic and pathological processes within tissues. Fibronectin consists of independently-folded modules termed Types I, II and III. In response to cellular contractile force, Type III domains unfold to initiate a series of homophilic binding events which result in the assembly of a complex network of intertwining fibrils. The unfolding of Type III modules provides elasticity to the assembled fibronectin matrix allowing it to function as a dynamic scaffold which provides binding sites for cellular receptors, growth factors and other matrix molecules. Access to bioactive sites within the fibronectin matrix is under complex regulation and controlled through a combination of mechanical and proteolytic activity. Mechanical unfolding of Type III modules and limited proteolysis can alter the topographical display of bioactive sites within the fibronectin fibrils by exposing previously cryptic sites and disrupting functional sites. In this review we will discuss cryptic activity found within the first Type III module of fibronectin and its impact on tissue angiogenesis and inflammation.

  17. Binding of tenascin-C to soluble fibronectin and matrix fibrils.

    PubMed

    Chung, C Y; Zardi, L; Erickson, H P

    1995-12-01

    The small splice variant of tenascin-C (TN) has eight fibronectin type III (FN3) domains. The major large splice variant has three (in chicken) or seven (in human) additional FN3 domains inserted between domains five and six. Chiquet-Ehrismann et al. (Chiquet-Ehrismann, R., Matsuoka, Y., Hofer, U., Spring, J., Bernasconi, C., and Chiquet, M. (1991, Cell Regul. 2, 927-938) demonstrated that the small variant bound preferentially to fibronectin in enzyme-linked immunosorbent assay, and only the small variant was incorporated into the matrix by cultures of chicken fibroblasts. Here we have studied human TN, and confirmed that the small variant binds preferentially to purified fibronectin and to fibronectin-containing extracellular matrix. Thus this differential binding appears to be conserved across vertebrate species. Using bacterial expression proteins, we mapped the major binding site to the third FN3 domain of TN. Consistent with this mapping, a monoclonal antibody against an epitope in this domain did not stain TN segments bound to cell culture matrix fibrils. The enhanced binding of the small TN variant suggests the existence of another, weak binding site probably in FN3 domains 6-8, which is only positioned to bind fibronectin in the small splice variant. This binding of domains 6-8 may involve a third molecule present in matrix fibrils, as the enhanced binding of small TN was much more prominent to matrix fibrils than to purified fibronectin. PMID:7499434

  18. Fibronectin and asialoglyprotein receptor mediate hepatitis B surface antigen binding to the cell surface.

    PubMed

    Yang, Jing; Wang, Feng; Tian, Linlin; Su, Jing; Zhu, Xiangqian; Lin, Li; Ding, Xiaoran; Wang, Xuejun; Wang, Shengqi

    2010-06-01

    Both fibronectin and the asialoglycoprotein receptor (ASGPR) have been identified by some investigators as partners for hepatitis B virus (HBV) envelope proteins. Because fibronectin is a natural ligand for ASGPR, we speculated that HBV might attach to ASGPR expressed on the hepatocyte surface via fibronectin. To test this hypothesis, we first confirmed by co-immunoprecipitation that ASGPR, fibronectin and HBsAg bind to each other in HepG2.2.15 cells, and possible binding domains were identified by GST pull-down. In addition, by measuring binding of HBsAg to cells, we found that ASGPR and fibronectin enhanced the binding capability of HBsAg to HepG2 cells, and even to 293T and CHO cells, which normally do not bind HBV. In conclusion, our findings suggest that both fibronectin and ASGPR mediate HBsAg binding to the cell surface, which provides further evidence for the potential roles of these two proteins in mediating HBV binding to liver cells. PMID:20364278

  19. Fibronectin-like protein in Porifera: its role in cell aggregation.

    PubMed Central

    Labat-Robert, J; Robert, L; Auger, C; Lethias, C; Garrone, R

    1981-01-01

    Experiments were carried out on a freshwater sponge (Ephydatia mulleri) in order to demonstrate the presence of fibronectin in Porifera. By using antibodies to highly purified human plasma fibronectin, the presence of a similar or identical protein could be demonstrated in the membranes of E. mulleri cells such as epithelial cells, fibroblast-like cells, and choanocytes. The reaction was specific, could be abolished by the addition of excess fibronectin, and was not observed with nonimmune rabbit serum. The immune fluorescent reaction became stronger when the sponge cells were pretreated with acetone and could also be observed, although with a less intense staining, on the intercellular matrix. This shows the predominant presence of a sponge fibronectin-like protein in the cell membranes and also its presence to a lesser extent in the intercellular matrix. When dissociated sponge cells were led to reassociate under the microscope, reassociation could be completely inhibited by anti-human fibronectin antiserum up to a dilution of 1:120 and partially inhibited up to a dilution of 1:240. The reassociation of dissociated sponge cells could also be inhibited by the addition of purified gelatin but not with serum albumin or with a normal, nonimmune rabbit serum. These results clearly indicate that a sponge cell fibronectin-like protein may play an important role as the (or one of the) recognition site(s) of the aggregation factor(s) and can therefore be directly involved in cell association, morphogenesis, and differentiation. Images PMID:7031644

  20. Expression of α5 integrin rescues fibronectin responsiveness in NT2N CNS neuronal cells

    PubMed Central

    Meland, Marit N.; Herndon, Mary E.; Stipp, Christopher S.

    2010-01-01

    The extracellular matrix protein fibronectin is implicated in neuronal regeneration in the peripheral nervous system. In the central nervous system (CNS), fibronectin is upregulated at sites of penetrating injuries and stroke; however, CNS neurons downregulate the fibronectin receptor, α5β1 integrin, during differentiation and generally respond poorly to fibronectin. NT2N CNS neuron-like cells (derived from NT2 precursor cells) have been used in pre-clinical and clinical studies for treatment of stroke and a variety of CNS injury and disease models. Here we show that, like primary CNS neurons, NT2N cells downregulate α5β1 integrin during differentiation and respond poorly to fibronectin. The poor neurite outgrowth by NT2N cells on fibronectin can be rescued by transducing NT2 precursors with a retroviral vector expressing α5 integrin under the control of the Murine Stem Cell Virus 5′ long terminal repeat. Sustained α5 integrin expression is compatible with the CNS-like neuronal differentiation of NT2N cells and does not prevent robust neurite outgrowth on other integrin ligands. Thus, α5 integrin expression in CNS neuronal precursor cells may provide a strategy for enhancing the outgrowth and survival of implanted cells in cell replacement therapies for CNS injury and disease. PMID:19598247

  1. Mapping the Ligand-Binding Region of Borrelia hermsii Fibronectin-Binding Protein

    PubMed Central

    Brenner, Christiane; Bomans, Katharina; Habicht, Jüri; Simon, Markus M.; Wallich, Reinhard

    2013-01-01

    Many pathogenic microorganisms express fibronectin-binding molecules that facilitate their adherence to the extracellular matrix and/or entry into mammalian cells. We have previously described a Borrelia recurrentis gene, cihC that encodes a 40-kDa surface receptor for both, fibronectin and the complement inhibitors C4bp and C1-Inh. We now provide evidence for the expression of a group of highly homologues surface proteins, termed FbpA, in three B. hermsii isolates and two tick-borne relapsing fever spirochetes, B. parkeri and B. turicatae. When expressed in Escherichia coli or B. burgdorferi, four out of five proteins were shown to selectively bind fibronectin, whereas none of five proteins were able to bind the human complement regulators, C4bp and C1-Inh. By applying deletion mutants of the B. hermsii fibronectin-binding proteins a putative high-affinity binding site for fibronectin was mapped to its central region. In addition, the fibronectin-binding proteins of B. hermsii were found to share sequence homology with BBK32 of the Lyme disease spirochete B. burgdorferi with similar function suggesting its involvement in persistence and/or virulence of relapsing fever spirochetes. PMID:23658828

  2. Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice.

    PubMed

    Lukjanenko, Laura; Jung, M Juliane; Hegde, Nagabhooshan; Perruisseau-Carrier, Claire; Migliavacca, Eugenia; Rozo, Michelle; Karaz, Sonia; Jacot, Guillaume; Schmidt, Manuel; Li, Liangji; Metairon, Sylviane; Raymond, Frederic; Lee, Umji; Sizzano, Federico; Wilson, David H; Dumont, Nicolas A; Palini, Alessio; Fässler, Reinhard; Steiner, Pascal; Descombes, Patrick; Rudnicki, Michael A; Fan, Chen-Ming; von Maltzahn, Julia; Feige, Jerome N; Bentzinger, C Florian

    2016-08-01

    Age-related changes in the niche have long been postulated to impair the function of somatic stem cells. Here we demonstrate that the aged stem cell niche in skeletal muscle contains substantially reduced levels of fibronectin (FN), leading to detrimental consequences for the function and maintenance of muscle stem cells (MuSCs). Deletion of the gene encoding FN from young regenerating muscles replicates the aging phenotype and leads to a loss of MuSC numbers. By using an extracellular matrix (ECM) library screen and pathway profiling, we characterize FN as a preferred adhesion substrate for MuSCs and demonstrate that integrin-mediated signaling through focal adhesion kinase and the p38 mitogen-activated protein kinase pathway is strongly de-regulated in MuSCs from aged mice because of insufficient attachment to the niche. Reconstitution of FN levels in the aged niche remobilizes stem cells and restores youth-like muscle regeneration. Taken together, we identify the loss of stem cell adhesion to FN in the niche ECM as a previously unknown aging mechanism. PMID:27376579

  3. Focal weakness following herpes zoster.

    PubMed Central

    Cockerell, O C; Ormerod, I E

    1993-01-01

    Three patients presented with focal weakness of an arm which followed segmental herpes zoster affecting the same limb. Neurophysiological investigations suggest that the site of the lesion lay at the root, plexus, or peripheral nerve level. This reflects the various ways in which the virus may affect the peripheral nervous system. PMID:8410022

  4. FibronectinEDA Promotes Chronic Cutaneous Fibrosis Through Toll-like Receptor Signaling

    PubMed Central

    Bhattacharyya, Swati; Tamaki, Zenshiro; Wang, Wenxia; Hinchcliff, Monique; Hoover, Paul; Getsios, Spiro; White, Eric S.; Varga, John

    2015-01-01

    Scleroderma is a progressive autoimmune disease affecting multiple organs. Fibrosis, the hallmark of scleroderma, represents transformation of self-limited wound healing into a deregulated self-sustaining process. The factors responsible for maintaining persistent fibroblast activation in scleroderma and other conditions with chronic fibrosis are not well understood. Toll-like receptor 4 (TLR4) and its damage-associated endogenous ligands are implicated in immune and fibrotic responses. We now show that fibronectin extra domain A (FnEDA) is an endogenous TLR4 ligand markedly elevated in the circulation and lesional skin biopsies from patients with scleroderma, as well as in mice with experimentally induced cutaneous fibrosis. Synthesis of FnEDA was preferentially stimulated by transforming growth factor–β in normal fibroblasts and was constitutively up-regulated in scleroderma fibroblasts. Exogenous FnEDA was a potent stimulus for collagen production, myofibroblast differentiation, and wound healing in vitro and increased the mechanical stiffness of human organotypic skin equivalents. Each of these profibrotic FnEDA responses was abrogated by genetic, RNA interference, or pharmacological disruption of TLR4 signaling. Moreover, either genetic loss of FnEDA or TLR4 blockade using a small molecule mitigated experimentally induced cutaneous fibrosis in mice. These observations implicate the FnEDA-TLR4 axis in cutaneous fibrosis and suggest a paradigm in which aberrant FnEDA accumulation in the fibrotic milieu drives sustained fibroblast activation via TLR4. This model explains how a damage-associated endogenous TLR4 ligand might contribute to converting self-limited tissue repair responses into intractable fibrogenesis in chronic conditions such as scleroderma. Disrupting sustained TLR4 signaling therefore represents a potential strategy for the treatment of fibrosis in scleroderma. PMID:24739758

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

    SciTech Connect

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

    1997-03-14

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

  6. EDA-containing fibronectin increases proliferation of embryonic stem cells.

    PubMed

    Losino, Noelia; Waisman, Ariel; Solari, Claudia; Luzzani, Carlos; Espinosa, Darío Fernández; Sassone, Alina; Muro, Andrés F; Miriuka, Santiago; Sevlever, Gustavo; Barañao, Lino; Guberman, Alejandra

    2013-01-01

    Embryonic stem cells (ESC) need a set of specific factors to be propagated. They can also grow in conditioned medium (CM) derived from a bovine granulosa cell line BGC (BGC-CM), a medium that not only preserves their main features but also increases ESC´s proliferation rate. The mitogenic properties of this medium were previously reported, ascribing this effect to an alternative spliced generated fibronectin isoform that contains the extra domain A (FN EDA(+)). Here, we investigated if the FN EDA(+) isoform increased proliferation of mouse and human ES cells. We analyzed cell proliferation using conditioned media produced by different mouse embryonic fibroblast (MEF) lines genetically engineered to express FN constitutively including or excluding the EDA domain (FN EDA(-)), and in media supplemented with recombinant peptides containing or not the EDA. We found that the presence of EDA in the medium increased mouse and human ESC's proliferation rate. Here we showed for the first time that this FN isoform enhances ESC's proliferation. These findings suggest a possible conserved behavior for regulation of ES cells proliferation by this FN isoform and could contribute to improve their culturing conditions both for research and cell therapy. PMID:24244705

  7. EDA-Containing Fibronectin Increases Proliferation of Embryonic Stem Cells

    PubMed Central

    Losino, Noelia; Waisman, Ariel; Solari, Claudia; Luzzani, Carlos; Espinosa, Darío Fernández; Sassone, Alina; Muro, Andrés F.; Miriuka, Santiago; Sevlever, Gustavo; Barañao, Lino; Guberman, Alejandra

    2013-01-01

    Embryonic stem cells (ESC) need a set of specific factors to be propagated. They can also grow in conditioned medium (CM) derived from a bovine granulosa cell line BGC (BGC-CM), a medium that not only preserves their main features but also increases ESC´s proliferation rate. The mitogenic properties of this medium were previously reported, ascribing this effect to an alternative spliced generated fibronectin isoform that contains the extra domain A (FN EDA+). Here, we investigated if the FN EDA+ isoform increased proliferation of mouse and human ES cells. We analyzed cell proliferation using conditioned media produced by different mouse embryonic fibroblast (MEF) lines genetically engineered to express FN constitutively including or excluding the EDA domain (FN EDA-), and in media supplemented with recombinant peptides containing or not the EDA. We found that the presence of EDA in the medium increased mouse and human ESC’s proliferation rate. Here we showed for the first time that this FN isoform enhances ESC’s proliferation. These findings suggest a possible conserved behavior for regulation of ES cells proliferation by this FN isoform and could contribute to improve their culturing conditions both for research and cell therapy. PMID:24244705

  8. Fibronectin fragments modulate monocyte VLA-5 expression and monocyte migration.

    PubMed

    Trial, J; Baughn, R E; Wygant, J N; McIntyre, B W; Birdsall, H H; Youker, K A; Evans, A; Entman, M L; Rossen, R D

    1999-08-01

    To identify the mechanisms that cause monocyte localization in infarcted myocardium, we studied the impact of ischemia-reperfusion injury on the surface expression and function of the monocyte fibronectin (FN) receptor VLA-5 (alpha(5)beta(1) integrin, CD49e/CD29). Myocardial infarction was associated with the release of FN fragments into cardiac extracellular fluids. Incubating monocytes with postreperfusion cardiac lymph that contained these FN fragments selectively reduced expression of VLA-5, an effect suppressed by specific immunoadsorption of the fragments. Treating monocytes with purified, 120-kDa cell-binding FN fragments (FN120) likewise decreased VLA-5 expression, and did so by inducing a serine proteinase-dependent proteolysis of this beta(1) integrin. We postulated that changes in VLA-5 expression, which were induced by interactions with cell-binding FN fragments, may alter monocyte migration into tissue FN, a prominent component of the cardiac extracellular matrix. Support for this hypothesis came from experiments showing that FN120 treatment significantly reduced both spontaneous and MCP-1-induced monocyte migration on an FN-impregnated collagen matrix. In vivo, it is likely that contact with cell-binding FN fragments also modulates VLA-5/FN adhesive interactions, and this causes monocytes to accumulate at sites where the fragment concentration is sufficient to ensure proteolytic degradation of VLA-5. PMID:10449434

  9. Fibronectin contributes to pathological cardiac hypertrophy but not physiological growth

    PubMed Central

    Konstandin, Mathias H.; Völkers, Mirko; Collins, Brett; Quijada, Pearl; Quintana, Mercedes; De La Torre, Andrea; Ormachea, Lucy; Din, Shabana; Gude, Natalie; Toko, Haruhiro; Sussman, Mark A.

    2013-01-01

    Background Ability of the heart to undergo pathological or physiological hypertrophy upon increased wall stress is critical for long-term compensatory function in response to increased workload demand. While substantial information has been published on the nature of the fundamental molecular signaling involved in hypertrophy, the role of extracellular matrix (ECM) protein Fibronectin (Fn) in hypertrophic signaling is unclear. Objective Delineate the role of Fn during pressure overload-induced pathological cardiac hypertrophy and physiological growth prompted by exercise. Methods and Results Genetic conditional ablation of Fn in adulthood blunts cardiomyocyte hypertrophy upon pressure overload via attenuated activation of Nuclear Factor of Activated T cells (NFAT). Loss of Fn delays development of heart failure and improves survival. In contrast, genetic deletion of Fn has no impact on physiological cardiac growth induced by voluntary wheel running. Down regulation of the transcription factor c/EBPβ (Ccaat-enhanced binding protein β), which is essential for induction of the physiological growth program, is unaffected by Fn deletion. Nuclear NFAT translocation is triggered by Fn in conjunction with up-regulation of the fetal gene program and hypertrophy of cardiomyocytes in vitro. Furthermore, activation of the physiological gene program induced by Insulin stimulation in vitro is attenuated by Fn, whereas Insulin had no impact on Fn-induced pathological growth program. Conclusion Fn contributes to pathological cardiomyocyte hypertrophy in vitro and in vivo via NFAT activation. Fn is dispensable for physiological growth in vivo, and Fn attenuates the activation of the physiological growth program in vitro. PMID:23912225

  10. Exposure to Biomass Smoke Extract Enhances Fibronectin Release from Fibroblasts

    PubMed Central

    Krimmer, David; Ichimaru, Yukikazu; Burgess, Janette; Black, Judith; Oliver, Brian

    2013-01-01

    COPD induced following biomass smoke exposure has been reported to be associated with a more fibrotic phenotype than cigarette smoke induced COPD. This study aimed to investigate if biomass smoke induced extracellular matrix (ECM) protein production from primary human lung fibroblasts in vitro. Primary human lung fibroblasts (n = 5–10) were stimulated in vitro for up to 72 hours with increasing concentrations of biomass smoke extract (BME) or cigarette smoke extract (CSE) prior to being assessed for deposition of ECM proteins, cytokine release, and activation of intracellular signalling molecules. Deposition of the ECM proteins perlecan and fibronectin was upregulated by both CSE (p<0.05) and BME (p<0.05). The release of the neutrophilic chemokine IL-8 was also enhanced by BME. ERK1/2 phosphorylation was significantly upregulated by BME (p<0.05). Chemical inhibition of ERK signalling molecules partially attenuated these effects (p<0.05). Stimulation with endotoxin had no effect. This study demonstrated that BME had similar effects to CSE in vitro and had the capacity to directly induce fibrosis by upregulating production of ECM proteins. The mechanisms by which both biomass and cigarette smoke exposure cause lung damage may be similar. PMID:24386310

  11. Fibronectin-Grafted Titanium Dental Implants: An In Vivo Study.

    PubMed

    Chang, Yu-Chi; Ho, Kuo-Ning; Feng, Sheng-Wei; Huang, Haw-Ming; Chang, Chia-Hsun; Lin, Che-Tong; Teng, Nai-Chia; Pan, Yu Hwa; Chang, Wei-Jen

    2016-01-01

    Modification of the physiochemical properties of titanium surfaces using glow discharge plasma (GDP) and fibronectin coating has been shown to enhance the surface hydrophilicity, surface roughness, cell adhesion, migration, and proliferation. This in vivo study aimed to evaluate the bone integration efficacy of a biologically modified implant surface. Two different surface-modified implants (Ar-GDP and GDP-fib) were placed in the mandibular premolar area of six beagle dogs for 2-8 weeks. Three techniques [histologic evaluation, resonance frequency analysis (RFA), and microcomputed tomography (micro-CT) evaluation] were used to detect the implant stability and bone-implant contact. The implant stability quotient values of GDP-fib implants were significantly greater than the Ar-GDP implants at 2 and 4 weeks (P < 0.01). The bone volume/total volume ratio of GDP-fib implants was greater than the Ar-GDP implants in micro-CT evaluation. A high positive correlation was observed between RFA and micro-CT measurements. At 2 weeks, osteoblasts were seen to line the implant surface, and multinuclear osteoclasts could be seen on the surface of old parent bone. After 8 weeks, a majority of the space in the wound chamber appeared to be replaced by bone. Enhancement of the stability of biologically modified implants was proved by the results of RFA, micro-CT, and histological analysis. This enhanced stability may help fasten treatment and be clinically beneficial. PMID:27366739

  12. Plasma fibronectin promotes thrombus growth and stability in injured arterioles

    PubMed Central

    Ni, Heyu; Yuen, Peter S. T.; Papalia, Jessie M.; Trevithick, Jane E.; Sakai, Takao; Fässler, Reinhard; Hynes, Richard O.; Wagner, Denisa D.

    2003-01-01

    Mice lacking both of the best-known platelet ligands, von Willebrand factor and fibrinogen, can still form occlusive thrombi in injured arterioles. The platelets of these animals accumulate excessive amounts of fibronectin (FN). These observations led us to examine the contribution of plasma FN (pFN) to thrombus formation. Inactivation of the FN gene in FN conditional knockout mice reduced pFN levels to <2% and platelet FN to ≈20% of the levels in similarly treated control mice. The mice were then observed in a model of arterial injury to evaluate their capacity to form thrombi. The deficiency of pFN did not affect the initial platelet adhesion, but a delay of several minutes in thrombus formation was observed in the arterioles of pFN-deficient mice as compared with control mice. The thrombi that formed in the absence of pFN were stably anchored to the vessel wall but continuously shed platelets or small platelet clumps, thus slowing their growth significantly; the platelet/platelet cohesion was apparently diminished. Consequently the occlusion of pFN-deficient vessels was delayed, with the majority of vessels remaining patent at the end of the 40-min observation period. We conclude that, in addition to von Willebrand factor and fibrinogen, FN plays a significant role in thrombus initiation, growth, and stability at arterial shear rates and that deficiency in each of the three platelet ligands has its own specific impact on platelet plug formation. PMID:12606706

  13. Fibronectin Fiber Extension Decreases Cell Spreading and Migration.

    PubMed

    Hubbard, Brant; Buczek-Thomas, Jo Ann; Nugent, Matthew A; Smith, Michael L

    2016-08-01

    The extracellular matrix (ECM) is present in a range of molecular conformations and intermolecular arrangements. Fibronectin (Fn) molecules that constitute fibers within the ECM can exist in a variety of conformations that result from both mechanical stress and chemical factors such as allosteric binding partners. The long-standing hypothesis that conformational changes regulate the binding of cells to Fn fibers has only been tested for mutated molecules of Fn and has yet to be fully evaluated with Fn fibers. Using time-lapse microscopy we examined how mechanical extension of single fibers of Fn affects the adhesion and migration of endothelial cells. Using this single fiber adhesion technique, we show that high levels of mechanical strain applied to Fn fibers decreases the rates of both cell spreading and cell migration. These data indicate a fundamental cellular response to mechanical strain in the ECM that might have important implications for understanding how cells are recruited during tissue development and repair. J. Cell. Physiol. 231: 1728-1736, 2016. © 2015 Wiley Periodicals, Inc. PMID:26621030

  14. Increased plasma fibronectin in patients with systemic lupus erythematosus.

    PubMed

    Nishinarita, S; Yamamoto, M; Takizawa, T; Hayakawa, J; Karasaki, M; Sawada, S

    1990-06-01

    To add to our knowledge of collagen diseases, plasma fibronectin (FN) in patients with systemic lupus erythematosus (SLE) has been measured, and it was determined that the plasma FN value in those with SLE was 454 +/- 36 micrograms/ml, is significantly higher than the FN value in normal subjects (234 +/- 21 micrograms/ml) than that of patients with FN value of patients with active SLE was significantly higher (591 +/- 46 micrograms/ml) that of the patients with non-active SLE (287 +/- 31 micrograms/ml). The plasma FN value of SLE patients was also seen to be associated with the peripheral blood platelet count and with the dose level of the corticosteroid hormone administered to patients. In active SLE patients, it was similarly found that the plasma FN value had a significant correlation with the peripheral blood lymphocyte count and with the dose level of the corticosteroid hormone given to patients. Since the plasma FN value is known to be high in untreated SLE patients, it was felt that the increase of the FN value in SLE patients is not due to the effect of the corticosteroid but to the disease itself. PMID:2202543

  15. Fibronectin-Grafted Titanium Dental Implants: An In Vivo Study

    PubMed Central

    Chang, Yu-Chi; Ho, Kuo-Ning; Feng, Sheng-Wei; Huang, Haw-Ming; Chang, Chia-Hsun; Lin, Che-Tong; Teng, Nai-Chia; Pan, Yu Hwa; Chang, Wei-Jen

    2016-01-01

    Modification of the physiochemical properties of titanium surfaces using glow discharge plasma (GDP) and fibronectin coating has been shown to enhance the surface hydrophilicity, surface roughness, cell adhesion, migration, and proliferation. This in vivo study aimed to evaluate the bone integration efficacy of a biologically modified implant surface. Two different surface-modified implants (Ar-GDP and GDP-fib) were placed in the mandibular premolar area of six beagle dogs for 2–8 weeks. Three techniques [histologic evaluation, resonance frequency analysis (RFA), and microcomputed tomography (micro-CT) evaluation] were used to detect the implant stability and bone-implant contact. The implant stability quotient values of GDP-fib implants were significantly greater than the Ar-GDP implants at 2 and 4 weeks (P < 0.01). The bone volume/total volume ratio of GDP-fib implants was greater than the Ar-GDP implants in micro-CT evaluation. A high positive correlation was observed between RFA and micro-CT measurements. At 2 weeks, osteoblasts were seen to line the implant surface, and multinuclear osteoclasts could be seen on the surface of old parent bone. After 8 weeks, a majority of the space in the wound chamber appeared to be replaced by bone. Enhancement of the stability of biologically modified implants was proved by the results of RFA, micro-CT, and histological analysis. This enhanced stability may help fasten treatment and be clinically beneficial. PMID:27366739

  16. Statistical earthquake focal mechanism forecasts

    NASA Astrophysics Data System (ADS)

    Kagan, Yan Y.; Jackson, David D.

    2014-04-01

    Forecasts of the focal mechanisms of future shallow (depth 0-70 km) earthquakes are important for seismic hazard estimates and Coulomb stress, and other models of earthquake occurrence. Here we report on a high-resolution global forecast of earthquake rate density as a function of location, magnitude and focal mechanism. In previous publications we reported forecasts of 0.5° spatial resolution, covering the latitude range from -75° to +75°, based on the Global Central Moment Tensor earthquake catalogue. In the new forecasts we have improved the spatial resolution to 0.1° and the latitude range from pole to pole. Our focal mechanism estimates require distance-weighted combinations of observed focal mechanisms within 1000 km of each gridpoint. Simultaneously, we calculate an average rotation angle between the forecasted mechanism and all the surrounding mechanisms, using the method of Kagan & Jackson proposed in 1994. This average angle reveals the level of tectonic complexity of a region and indicates the accuracy of the prediction. The procedure becomes problematical where longitude lines are not approximately parallel, and where shallow earthquakes are so sparse that an adequate sample spans very large distances. North or south of 75°, the azimuths of points 1000 km away may vary by about 35°. We solved this problem by calculating focal mechanisms on a plane tangent to the Earth's surface at each forecast point, correcting for the rotation of the longitude lines at the locations of earthquakes included in the averaging. The corrections are negligible between -30° and +30° latitude, but outside that band uncorrected rotations can be significantly off. Improved forecasts at 0.5° and 0.1° resolution are posted at http://eq.ess.ucla.edu/kagan/glob_gcmt_index.html.

  17. Distracted Driving

    MedlinePlus

    ... combines all three types of distraction. 3 How big is the problem? Deaths In 2013, 3,154 ... European countries. More A CDC study analyzed 2011 data on distracted driving, including talking on a cell ...

  18. Distracted driving

    MedlinePlus

    ... stay safe with a cell phone in the car. ... for Disease Control and Prevention Injury Prevention & Control. Motor Vehicle Safety. www.cdc.gov/motorvehiclesafety/distracted_driving . Accessed May ...

  19. Driving Safely

    MedlinePlus

    ... drivers’ flexibility and coordination, and reduced driving errors. S l Hand grip strengthening to help you hold on to the steering wheel l Shoulder and upper arm flexibility exercises to make ...

  20. Interactions between integrin receptors and fibronectin are required for calvarial osteoblast differentiation in vitro

    NASA Technical Reports Server (NTRS)

    Moursi, A. M.; Globus, R. K.; Damsky, C. H.

    1997-01-01

    We previously showed that anti-fibronectin antibodies or soluble fibronectin fragments containing the central cell-binding domain inhibit formation of mineralized nodules by fetal calvarial osteoblasts in vitro. These findings suggest a critical role for fibronectin in osteoblast differentiation and morphogenesis. In this study we tested the hypothesis that fibronectin's effects on osteogenesis are mediated via direct interactions with integrin receptors for fibronectin on osteoblasts. Immunocytochemical analysis identified the integrin fibronectin receptor alpha5ss1 in fetal rat calvarial tissue and in cultured osteoblasts at all stages of differentiation. Three other integrins, alpha3ss1, alpha8ss1 and alphavss3, which can bind fibronectin, as well as other matrix components, were also identified in tissue and at all stages of cell culture. Immunoprecipitation data showed that alpha5ss1 levels are constant throughout osteoblast differentiation whereas levels of alpha3ss1 and alpha8ss1 decline in mature mineralized cultures. To determine whether integrin fibronectin receptors are required for osteoblast formation of mineralized nodules, we examined the extent of nodule formation in the presence and absence of function-perturbing anti-integrin antibodies. The antibodies were present continuously in cultures beginning at confluence (day 3), and nodule formation was measured at days 10 and 20. An anti-alpha5 integrin subunit antibody reduced nodule formation to less than 5% of control values at both time points. Inhibition of nodule formation was reversible and did not affect cell attachment and viability. Function-perturbing antibodies against alpha3ss1 and alpha8ss1 also reduced nodule formation, to less than 20% of control values. In contrast, function-perturbing antibodies to alphavss3 and alphavss5 did not affect nodule formation, indicating that the inhibitions noted were indeed specific. To determine the effect of antibody treatment on gene expression, steady

  1. Quantification of fibronectin as a method to assess ex vivo extracellular matrix remodeling.

    PubMed

    Bager, C L; Gudmann, N; Willumsen, N; Leeming, D J; Karsdal, M A; Bay-Jensen, A C; Høgdall, E; Balslev, I; He, Y

    2016-09-16

    Altered architecture, composition and quality of the extracellular matrix (ECM) are pathological hallmarks of several inflammatory and fibro-proliferative pathological processes such as osteoarthritis (OA), rheumatoid arthritis (RA), fibrosis and cancer. One of the most important components of the ECM is fibronectin. Fibronectin serves as an adhesion molecule anchoring cells to the underlying basement membrane through direct interaction with integrin receptors. Fibronectin hereby modulates the properties of the ECM and affects cellular processes. Quantification of fibronectin remodeling could therefore be used to assess the changes in the ECM that occur during progression of fibro-proliferative pathologies. Ex vivo models are becoming state-of-the-art tools to study ECM remodeling as the cellular composition and the organization of the ECM are preserved. Ex vivo models may therefore be a valuable tool to study the ECM remodeling that occurs during progression of fibro-proliferative pathologies. The aim of this study was to quantify fibronectin remodeling in ex vivo models of cartilage and cancer. A competitive The enzyme-linked immunosorbent assay (ELISA) against the C-terminus of fibronectin was developed (FBN-C). The assay was evaluated in relation to specificity, technical performance and as a marker for quantification of fibronectin in cartilage and cancer ex vivo models. The ELISA was specific and technically stable. Cleavage of tumor tissue with MMP-2 released significantly higher levels of FBN-C compared to tissue with buffer only and western blot analysis revealed that FBN-C recognizes both full length and degraded fibronectin. When ex vivo cartilage cultures were stimulated with the anabolic factor TGFβ and catabolic factors TNF-α and OSM, significantly higher levels of FBN-C were found in the conditioned media. Lastly, FBN-C was released from a cancer ex vivo model. In conclusion, we were able to quantify fibronectin remodeling in ex vivo models

  2. Fibronectin fibrillogenesis facilitates mechano-dependent cell spreading, force generation, and nuclear size in human embryonic fibroblasts.

    PubMed

    Scott, Lewis E; Mair, Devin B; Narang, Jiten D; Feleke, Kirubel; Lemmon, Christopher A

    2015-11-01

    Cells respond to mechanical cues from the substrate to which they are attached. These mechanical cues drive cell migration, proliferation, differentiation, and survival. Previous studies have highlighted three specific mechanisms through which substrate stiffness directly alters cell function: increasing stiffness drives (1) larger contractile forces; (2) increased cell spreading and size; and (3) altered nuclear deformation. While studies have shown that substrate mechanics are an important cue, the role of the extracellular matrix (ECM) has largely been ignored. The ECM is a crucial component of the mechanosensing system for two reasons: (1) many ECM fibrils are assembled by application of cell-generated forces, and (2) ECM proteins have unique mechanical properties that will undoubtedly alter the local stiffness sensed by a cell. We specifically focused on the role of the ECM protein fibronectin (FN), which plays a critical role in de novo tissue production. In this study, we first measured the effects of substrate stiffness on human embryonic fibroblasts by plating cells onto microfabricated pillar arrays (MPAs) of varying stiffness. Cells responded to increasing substrate stiffness by generating larger forces, spreading to larger sizes, and altering nuclear geometry. These cells also assembled FN fibrils across all stiffnesses, with optimal assembly occurring at approximately 6 kPa. We then inhibited FN assembly, which resulted in dramatic reductions in contractile force generation, cell spreading, and nuclear geometry across all stiffnesses. These findings suggest that FN fibrils play a critical role in facilitating cellular responses to substrate stiffness. PMID:26412391

  3. Analysis of Soluble Molecular Fibronectin-Fibrin Complexes and EDA-Fibronectin Concentration in Plasma of Patients with Atherosclerosis.

    PubMed

    Lemańska-Perek, Anna; Krzyżanowska-Gołąb, Dorota; Pupek, Małgorzata; Klimeczek, Piotr; Witkiewicz, Wojciech; Kątnik-Prastowska, Iwona

    2016-06-01

    Atherosclerosis, a chronic vascular disease, leads to molecular events bound with interplaying processes of inflammation and coagulation. In the present study, fibronectin (FN), FN containing extra domain A (EDA-FN), frequency of occurrence, and relative amounts of soluble plasma FN-fibrin complexes were analyzed in 80 plasma samples of patients suspected of coronary artery disease based on clinical evaluation and changes in arteries found by computed tomographic coronary angiography. The study showed that in the plasma of the patients' group with high risk of coronary artery disease EDA-FN concentration was significantly higher (3.5 ± 2.5 mg/L; P < 0.025) and the molecular FN-fibrin complexes of 1000 kDa and higher occurred more often than in the groups of patients with mild risk of coronary artery disease and the normal age-matched. The increased level of EDA-FN and occurrence of FN-fibrin complexes could have a potential diagnostic value in the diagnosis and management of patients with coronary artery disease. PMID:27022744

  4. Fibronectin Regulation by Vitamin C Treatment in Kidneys of Nicotinic Mice Offspring

    PubMed Central

    Pahang, Hasan; Nikravesh, Mohammad Reza; Jalali, Mehdi; Ebrahimzadeh Bideskan, Alireza; Zargari, Peyman; Sadr Nabavi, Ariane

    2014-01-01

    Background: Maternal cigarette smoking causes health risks and developmental defects in the offspring. So far, many studies have been conducted to suppress the effects of nicotine. However, the effects of coadministration of vitamin C and nicotine on extracellular matrix have not gained enough attention. Objectives: This study decided to investigate the effects of vitamin C on fibronectin expression in kidneys of mice offspring, treated with nicotine. Materials and Methods: Eighteen female pregnant BALB/c mice were selected; six mice in the experimental group 1 (exp 1) received nicotine (3 mg/kg/day), six mice in the experimental group 2 (exp 2) received 3 mg/kg/day nicotine and 9 mg/kg/day vitamin C simultaneously, and six were used as the control group and received 3 mL/kg/day normal saline via intraperitoneal (IP) injection parallel to other groups, since the 6th day of gestation to the end of prenatal period. In the first days of delivery, fibronectin content of neonatal kidneys was studied by immunohistochemistry (IHC) assay and gene expression was studied by the real-time PCR. Results: IHC results showed that fibronectin reaction significantly increased in proximal convoluted tubules of exp 1 compared with the control offspring; on the other hand, fibronectin reaction decreased in the mice offspring of exp 2. Gene expression results showed that fibronectin expression in the exp 1 offspring significantly increased compared with the control ones and fibronectin expression decreased in the mice offspring of exp 2. Conclusions: This study revealed that vitamin C could reduce the fibronectin accumulation effects of nicotine on kidney. PMID:25237577

  5. Trop-2 is up-regulated in invasive prostate cancer and displaces FAK from focal contacts.

    PubMed

    Trerotola, Marco; Ganguly, Kirat K; Fazli, Ladan; Fedele, Carmine; Lu, Huimin; Dutta, Anindita; Liu, Qin; De Angelis, Tiziana; Riddell, Luke W; Riobo, Natalia A; Gleave, Martin E; Zoubeidi, Amina; Pestell, Richard G; Altieri, Dario C; Languino, Lucia R

    2015-06-10

    In this study, we show that the transmembrane glycoprotein Trop-2 is up-regulated in human prostate cancer (PCa) with extracapsular extension (stages pT3/pT4) as compared to organ-confined (stage pT2) PCa. Consistent with this evidence, Trop-2 expression is found to be increased in metastatic prostate tumors of Transgenic Adenocarcinoma of Mouse Prostate mice and to strongly correlate with α5β1 integrin levels. Using PCa cells, we show that Trop-2 specifically associates with the α5 integrin subunit, as binding to α3 is not observed, and that Trop-2 displaces focal adhesion kinase from focal contacts. In support of the role of Trop-2 as a promoter of PCa metastatic phenotype, we observe high expression of this molecule in exosomes purified from Trop-2-positive PCa cells. These vesicles are then found to promote migration of Trop-2-negative PCa cells on fibronectin, an α5β1 integrin/focal adhesion kinase substrate, thus suggesting that the biological function of Trop-2 may be propagated to recipient cells. In summary, our findings show that Trop-2 promotes an α5β1 integrin-dependent pro-metastatic signaling pathway in PCa cells and that the altered expression of Trop-2 may be utilized for early identification of capsule-invading PCa. PMID:26015409

  6. MRI of Focal Liver Lesions.

    PubMed

    Albiin, Nils

    2012-05-01

    Magnetic resonance imaging, MRI has more advantages than ultrasound, computed tomography, CT, positron emission tomography, PET, or any other imaging modality in diagnosing focal hepatic masses. With a combination of basic T1 and T2 weighted sequences, diffusion weighted imaging, DWI, and hepatobiliary gadolinium contrast agents, that is gadobenate dimeglumine (Gd-BOPTA) and gadoxetic acid (Gd-EOB), most liver lesions can be adequately diagnosed. Benign lesions, as cyst, hemangioma, focal nodular hyperplasia, FNH or adenoma, can be distinguished from malignant lesions. In a non-cirrhotic liver, the most common malignant lesions are metastases which may be hypovascular or hypervascular. In the cirrhotic liver hepatocellular carcinoma, HCC, is of considerable importance. Besides, intrahepatic cholangiocarcinoma and other less common malignancies has to be assessed. In this review, the techniques and typical MRI features are presented as well as the new algorithm issued by American Association for the Study of the Liver Diseases (AASLD). PMID:23049491

  7. Variable focal length deformable mirror

    DOEpatents

    Headley, Daniel; Ramsey, Marc; Schwarz, Jens

    2007-06-12

    A variable focal length deformable mirror has an inner ring and an outer ring that simply support and push axially on opposite sides of a mirror plate. The resulting variable clamping force deforms the mirror plate to provide a parabolic mirror shape. The rings are parallel planar sections of a single paraboloid and can provide an on-axis focus, if the rings are circular, or an off-axis focus, if the rings are elliptical. The focal length of the deformable mirror can be varied by changing the variable clamping force. The deformable mirror can generally be used in any application requiring the focusing or defocusing of light, including with both coherent and incoherent light sources.

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

    SciTech Connect

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

    1996-11-15

    The authors have examined the role of the {beta}{sub 1} integrin family of adhesion receptors (VLA) and the extracellular matrix protein fibronectin (FN) in macrophage differentiation of (1) human HL-60 myeloid leukemia cells induced by phorbol 12-myristate 13-acetate (PMA) and (2) human peripheral blood monocytes induced by either PMA or macrophage-colony stimulating factor (M=CSF). Increased VLA and FN gene expression was observed as early as 4 h after PMA treatment of HL-60 cells and PMA- or M-CSF-treatment of monocytes, and it preceded the manifestation of macrophage markers. Treated HL-60 cells and monocytes also released and deposited FN on the surface of the tissue culture dishes. An HL-60 cell variant, HL-525, which is deficient in protein kinase C {beta} and resistant to PMA-induced differentiation, exhibited elevated levels of the VLA antigen but failed to express the FN gene. Incubation of HL-525 cells on dishes precoated with exogenous FN resulted in a macrophage differentiation. The macrophage phenotype induced in HL-60 cells, HL-525 cells, or monocytes was attenuated to various degrees by anti-VLA or anti-FN MAbs or by exogenous RGDS, a VLA-binding motif on FN. The authors suggest that macrophage differentiation is initiated by the activation of protein kinase C, which leads to the expression of the integrin, FN and related genes. The integrins mediate cell attachment and spreading on appropriate substrates by binding to deposited extracellular proteins such as FN. This attachment and spreading, in turn, leads to the expression of genes that code for the macrophage functions.

  9. Novel Mycobacteria Antigen 85 Complex Binding Motif on Fibronectin*

    PubMed Central

    Kuo, Chih-Jung; Bell, Hannah; Hsieh, Ching-Lin; Ptak, Christopher P.; Chang, Yung-Fu

    2012-01-01

    The members of the antigen 85 protein family (Ag85), consisting of members Ag85A, Ag85B, and Ag85C, are the predominantly secreted proteins of mycobacteria and possess the ability to specifically interact with fibronectin (Fn). Because Fn-binding proteins are likely to be important virulence factors of Mycobacterium spp., Ag85 may contribute to the adherence, invasion, and dissemination of organisms in host tissue. In this study, we reported the Fn binding affinity of Ag85A, Ag85B, and Ag85C from Mycobacterium avium subsp. paratuberculosis (MAP) (KD values were determined from 33.6 to 68.4 nm) and mapped the Ag85-binding motifs of Fn. Fn14, a type III module located on the heparin-binding domain II (Hep-2) of Fn, was discovered to interact with Ag85 from MAP. The peptide inhibition assay subsequently demonstrated that a peptide consisting of residues 17–26 from Fn14 (17SLLVSWQPPR26, termed P17–26) could interfere with Ag85B binding to Fn (73.3% reduction). In addition, single alanine substitutions along the sequence of P17–26 revealed that the key residues involved in Ag85-Fn binding likely contribute through hydrophobic and charge interactions. Moreover, binding of Ag85 on Fn siRNA-transfected Caco2 cells was dramatically reduced (44.6%), implying the physiological significance of the Ag85-Fn interaction between mycobacteria and host cells during infection. Our results indicate that Ag85 binds to Fn at a novel motif and plays a critical role in mycobacteria adherence to host cells by initiating infection. Ag85 might serve as an important colonization factor potentially contributing to mycobacterial virulence. PMID:22128161

  10. Modulation of endothelial cell adhesion to synthetic vascular grafts using biotinylated fibronectin in a dual ligand protein system

    NASA Astrophysics Data System (ADS)

    Anamelechi, Charles Chibuzor

    Over half a million coronary artery bypass operations are performed annually in the US yielding an annual health care cost of over 16 billion dollars. Only five percent of bypasses are repeat operations in spite of the procedures prevalence. Patients facing repeat coronary artery bypass operations often lack transplantable autologous arteries or veins, necessitating the use of substitutes. Unfortunately, synthetic small diameter vascular grafts have unacceptable patency rates, primarily due to lumenal thrombus formation and intimal thickening. Endothelial cells (EC) mediate the anti-thrombotic activity in healthy blood vessels, and due to the scarcity of suitable autologous vascular replacement, EC-seeded small diameter synthetic vascular grafts represent a clear, immediate, and practical solution. The fundamental goal of this project was to optimize the dual ligand (DL) system on synthetic vascular graft (SVG) surrogates to show enhanced cell adhesion, retention, and native functionality compared to fibronectin alone. Initially, two SVG surrogates were identified through characterization by x-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and 125I radiolabeling. The first modification to the DL system involved direct biotinylation of fibronectin (bFN) as a replacement for co-adsorption of FN with biotinylated bovine serum albumin (bBSA). This was analyzed with a Langmuir model using surface plasmon resonance (SPR) spectroscopy to verify the binding affinity of bFN and ELISA to detect the availability of the RGD binding motif post biotinylation. The second major change in this project examined cell binding and formation of focal adhesion after shifting from direct incubation of HUVECs with RGD-SA to sequentially adsorbing bFN(9) and RGD-SA prior to introducing unmodified HUVECs. These experiments were conducted under static seeding conditions. Next, dynamic cell seeding onto the sequentially adsorbed protein surface was examined as a function

  11. [Focal liver lesion, incidental finding].

    PubMed

    Dietrich, C F; Jenssen, C

    2012-10-01

    The differential diagnosis of incidentally found Focal Liver Lesions (FLL) is complex. Screening procedures so far are only defined for patients with liver cirrhosis. Characterization of a FLL begins as soon as it is detected. Taking patients history and thorough clinical examination are essential. An imaging procedure that is used to detect liver masses should also allow the examiner to determine whether the lesion is benign or malignant. Conventional B-mode US and colour Doppler imaging are effective at detecting and characterizing typical liver cysts and calcifications. Laboratory data, computed tomography, magnetic resonance imaging and imaging guided liver biopsy are complementary methods.Contrast Enhanced Ultrasound (CEUS) is a well established diagnostic imaging technique for a variety of indications and applications. One of the most important applications is in the liver where it is frequently a first-line technique for the detection and diagnosis (characterization) of focal liver lesions (FLL). In this setting the accurate differentiation of benign from malignant lesions is critical to ensure the patient undergoes the appropriate therapeutic option. This has been documented in recently published guidelines, in particular in terms of the enhancement patterns of the most common FLL hemangioma, focal nodular hyperplasia hepatocellular adenoma and their differentiation from malignant lesions. In this article the role of CEUS in the characterization of incidentally found FLL is described. PMID:23033169

  12. Persistent Focal Behavior and Physical Activity Performance

    ERIC Educational Resources Information Center

    Erfle, Stephen E.

    2014-01-01

    This article examines the proclivity and performance attributes of focal students across time and activities using data from 9,345 students. Three systematic focal behavior partitions are examined: Across activities, across time, and across activities and time. A student's performance is focal if it ends in 0 or 5 for push-ups and 0 for…

  13. Epstein–Barr virus LMP1 induces focal adhesions and epithelial cell migration through effects on integrin-α5 and N-cadherin

    PubMed Central

    Wasil, L R; Shair, K H Y

    2015-01-01

    Epstein–Barr virus (EBV) is a γ-herpesvirus associated with human epithelial and B-cell malignancies. The EBV latent membrane protein (LMP) 1 is expressed in nasopharyngeal carcinoma (NPC) and promotes oncogenic intracellular signaling mechanisms. LMP1 also promotes a pro-migratory phenotype through potential effects on cell surface proteins, as expression of LMP1 induces an epithelial–mesenchymal transition (EMT) in epithelial cell lines. In this study, LMP1 was examined for potential effects on cadherin and integrin surface interactions, and assessed for biological effects on adhesion and motility to fibronectin. Expression of LMP1 in the non-tumorigenic epithelial cell line MCF10a induced an EMT-associated cadherin switch. The induced N-cadherin was ligated and localized to the cell surface as determined by triton-solubility and immunofluorescence assays. In addition, LMP1 induced the assembly of focal adhesions (FAs) with increased production of fibronectin in MCF10a and NP460hTERT-immortalized nasopharyngeal cells. Biochemical enrichment of fibronectin-associated proteins indicated that LMP1 selectively promoted the recruitment of integrin-α5 and Src family kinase proteins to FA complexes. Neutralizing antibodies to N-cadherin and integrin-α5, but not integrin-αV, blocked the adhesion and transwell motility of MCF10a cells to fibronectin induced by LMP1. LMP1-induced transwell motility was also decreased by Src inhibition with the PP2 kinase inhibitor and short hairpin RNAs. These studies reveal that LMP1 has multiple mechanisms to promote the adhesive and migratory properties of epithelial cells through induction of fibronectin and modulation of cell surface interactions involving integrin-α5 and N-cadherin, which may contribute to the metastatic potential of NPC. PMID:26479443

  14. Fibronectin and Cyclic Strain Improve Cardiac Progenitor Cell Regenerative Potential In Vitro.

    PubMed

    French, Kristin M; Maxwell, Joshua T; Bhutani, Srishti; Ghosh-Choudhary, Shohini; Fierro, Marcos J; Johnson, Todd D; Christman, Karen L; Taylor, W Robert; Davis, Michael E

    2016-01-01

    Cardiac progenitor cells (CPCs) have rapidly advanced to clinical trials, yet little is known regarding their interaction with the microenvironment. Signaling cues present in the microenvironment change with development and disease. This work aims to assess the influence of two distinct signaling moieties on CPCs: cyclic biaxial strain and extracellular matrix. We evaluate four endpoints for improving CPC therapy: paracrine signaling, proliferation, connexin43 expression, and alignment. Vascular endothelial growth factor A (about 900 pg/mL) was secreted by CPCs cultured on fibronectin and collagen I. The application of mechanical strain increased vascular endothelial growth factor A secretion 2-4-fold for CPCs cultured on poly-L-lysine, laminin, or a naturally derived cardiac extracellular matrix. CPC proliferation was at least 25% higher on fibronectin than that on other matrices, especially for lower strain magnitudes. At 5% strain, connexin43 expression was highest on fibronectin. With increasing strain magnitude, connexin43 expression decreased by as much as 60% in CPCs cultured on collagen I and a naturally derived cardiac extracellular matrix. Cyclic mechanical strain induced the strongest CPC alignment when cultured on fibronectin or collagen I. This study demonstrates that culturing CPCs on fibronectin with 5% strain magnitude is optimal for their vascular endothelial growth factor A secretion, proliferation, connexin43 expression, and alignment. PMID:27610140

  15. The glycation of fibronectin by glycolaldehyde and methylglyoxal as a model for aging in Bruch's membrane.

    PubMed

    Thao, Mai T; Gaillard, Elizabeth R

    2016-07-01

    The purpose of the study is to identify the sites of modification when fibronectin reacts with glycolaldehyde or methylglyoxal as a model system for aging of Bruch's membrane. A synthetic peptide consisting of the α5β1 integrin binding region of fibronectin was incubated with glycolaldehyde for 12 h or with methylglyoxal for 1 h at 37 °C. After tryptic digestion, the samples were analyzed with liquid chromatography-mass spectrometry (LC/MS). Tandem MS was used to determine the sites of modification. The adducts, aldoamine and N (ε)-carboxymethyl-lysine, attached preferably at lysine residues when the fibronectin peptide reacted with glycolaldehyde. When the fibronectin peptide reacted with methylglyoxal, modifications occurred at lysine and arginine residues. At lysine residues, N (ε)-carboxyethyl-lysine adducts were present. At arginine residues, hydroimidazolone and tetrapyrimidine adducts were present. Several advanced glycation endproducts were generated when fibronectin was glycated via glycolaldehyde and methylglyoxal. These results can help explain the structural changes Bruch's membrane undergoes during aging. PMID:27084712

  16. Matrix fibronectin disruption and altered endothelial cell adhesion induced by activated leukocytes

    SciTech Connect

    Vincent, P.; Richards, P.; Saba, T.; DelVecchio, P.

    1986-03-01

    Sequestration of activated leukocytes (PMN) within the lung may contribute to pulmonary vascular injury following trauma, sepsis, or intravascular coagulation. Monolayers of cultured rat endothelial cells were utilized to evaluate the effect of activated PMNs on endothelial cell attachment and the extracellular fibronectin matrix over a 4 hr incubation interval. Rat endothelial cells were identified by immunofluorescent staining of Factor VIII R:Ag. Endothelial cells were labeled with /sup 51/Cr in order to establish a cell injury assay in which the release of pelletable (cell associated) or non-pelletable activity was measured in the media. PMN activation was verified by chemiluminescence activity. Following phorbol myristate acetate (PMA) the leukocytes aggregated, chemiluminesced, and caused detachment of /sup 51/Cr endothelial cells. Endothelial detachment increased as a function of time with a plateau by 3 hrs. Immunofluorescent analysis of extracellular fibronectin in endothelial cell cultures revealed disruption of the fibrillar matrix fibronectin in association with endothelial cell disadhesion. Matrix fibronectin disruption was not seen with PMNs or PMA alone. Thus, disruption of the fibronectin matrix by released proteases may contribute to endothelial cell detachment.

  17. Fibronectin and Cyclic Strain Improve Cardiac Progenitor Cell Regenerative Potential In Vitro

    PubMed Central

    Ghosh-Choudhary, Shohini; Fierro, Marcos J.; Christman, Karen L.; Taylor, W. Robert

    2016-01-01

    Cardiac progenitor cells (CPCs) have rapidly advanced to clinical trials, yet little is known regarding their interaction with the microenvironment. Signaling cues present in the microenvironment change with development and disease. This work aims to assess the influence of two distinct signaling moieties on CPCs: cyclic biaxial strain and extracellular matrix. We evaluate four endpoints for improving CPC therapy: paracrine signaling, proliferation, connexin43 expression, and alignment. Vascular endothelial growth factor A (about 900 pg/mL) was secreted by CPCs cultured on fibronectin and collagen I. The application of mechanical strain increased vascular endothelial growth factor A secretion 2–4-fold for CPCs cultured on poly-L-lysine, laminin, or a naturally derived cardiac extracellular matrix. CPC proliferation was at least 25% higher on fibronectin than that on other matrices, especially for lower strain magnitudes. At 5% strain, connexin43 expression was highest on fibronectin. With increasing strain magnitude, connexin43 expression decreased by as much as 60% in CPCs cultured on collagen I and a naturally derived cardiac extracellular matrix. Cyclic mechanical strain induced the strongest CPC alignment when cultured on fibronectin or collagen I. This study demonstrates that culturing CPCs on fibronectin with 5% strain magnitude is optimal for their vascular endothelial growth factor A secretion, proliferation, connexin43 expression, and alignment. PMID:27610140

  18. Polymorphisms in Fibronectin Binding Protein A of Staphylococcus Aureus are Associated with Infection of Cardiovascular Devices

    SciTech Connect

    Lower, Steven; Lamlertthon, Supaporn; Casillas-Ituarte, Nadia; Lins, Roberto D.; Yongsunthon, Ruchirej; Taylor, Eric S.; DiBartola, Alex; Edmondson, Catherine; McIntyre, Lauren M.; Reller, L. Barth; Que, Yok-Ai; Ros, Robert; Lower, Brian; Fowler, Vance

    2011-11-08

    Medical implants, like cardiovascular devices, improve the quality of life for countless individuals but may become infected with bacteria like Staphylococcus aureus. Such infections take the form of a bio-film, a structured community of bacterial cells adherent to the surface of a solid substrate. Every bio-film begins with an attractive force or bond between bacterium and substratum. We used atomic force microscopy to probe experimentally forces between a fibronectin-coated surface (i.e., proxy for an implanted cardiac device) and fibronectin-binding receptors on the surface of individual living bacteria from each of 80 clinical isolates of S. aureus. These isolates originated from humans with infected cardiac devices (CDI; n = 26), uninfected cardiac devices (n = 20), and the anterior nares of asymptomatic subjects (n = 34). CDI isolates exhibited a distinct bindingforce signature and had speci!c single amino acid polymorphisms in fibronectin-binding protein A corresponding to E652D, H782Q, and K786N. In silico molecular dynamics simulations demonstrate that residues D652, Q782, and N786 in fibronectin-binding protein A form extra hydrogen bonds with fibronectin, complementing the higher binding force and energy measured by atomic force microscopy for the CDI isolates. This study is significant, because it links pathogenic bacteria biofilms from the length scale of bonds acting across a nanometer-scale space to the clinical presentation of disease at the human dimension.

  19. Fibronectin Binding Protein BBK32 of the Lyme Disease Spirochete Promotes Bacterial Attachment to Glycosaminoglycans

    PubMed Central

    Fischer, Joshua R.; LeBlanc, Kimberly T.; Leong, John M.

    2006-01-01

    Borrelia burgdorferi, the agent of Lyme disease, causes a multisystemic illness that can affect the skin, heart, joints, and nervous system and is capable of attachment to diverse cell types. Among the host components recognized by this spirochete are fibronectin and glycosaminoglycans (GAGs). Three surface-localized GAG-binding bacterial ligands, Bgp, DbpA, and DbpB, have been previously identified, but recent studies suggested that at least one additional GAG-binding ligand is expressed on the spirochetal surface when the spirochete is adapted to the mammalian host environment. BBK32 is a surface lipoprotein that is produced during infection and that has been shown to bind to fibronectin. In this study, we show that, when BBK32 was produced from a shuttle vector in an otherwise nonadherent high-passage B. burgdorferi strain, the protein localized on the bacterial surface and conferred attachment to fibronectin and to mammalian cell monolayers. In addition, the high-passage strain producing BBK32 bound to purified preparations of the GAGs dermatan sulfate and heparin, as well as to these GAGs on the surfaces of cultured mammalian cells. Recombinant BBK32 recognized purified heparin, indicating that the bacterial attachment to GAGs was due to direct binding by BBK32. This GAG-binding activity of BBK32 is apparently independent of fibronectin recognition, because exogenous heparin had no effect on BBK32-mediated bacterial binding to fibronectin. PMID:16368999

  20. Lipoprotein(a) binds to fibronectin and has serine proteinase activity capable of cleaving it.

    PubMed Central

    Salonen, E M; Jauhiainen, M; Zardi, L; Vaheri, A; Ehnholm, C

    1989-01-01

    The plasma concentration of human lipoprotein(a) [Lp(a)] is correlated with the risk of heart disease. A distinct feature of the Lp(a) particle is the apolipoprotein (a) [apo(a)], which is associated with apoB-100, the main protein component of low-density lipoprotein. We now report that apo(a), which has extensive homology to plasminogen, binds to immobilized fibronectin. The binding of Lp(a) was localized to the C-terminal heparin-binding domain of fibronectin. Incubation of Lp(a) with fibronectin resulted in fragmentation of fibronectin. The cleavage pattern, as visualized by gel electrophoresis and immunoblotting, was reproducibly obtained with Lp(a) purified from five different individuals and was distinct from that obtained upon proteolysis of fibronectin by plasmin or kallikrein. The use of synthetic peptide substrates demonstrated that the amino acid specificity for Lp(a) was arginine rather than lysine. The proteolytic activity of Lp(a) was localized to apo(a) and experiments with inhibitors indicated that the proteolytic activity was of serine proteinase-type. Images PMID:2531657

  1. Polymorphisms in fibronectin binding protein A of Staphylococcus aureus are associated with infection of cardiovascular devices

    PubMed Central

    Lower, Steven K.; Lamlertthon, Supaporn; Casillas-Ituarte, Nadia N.; Lins, Roberto D.; Yongsunthon, Ruchirej; Taylor, Eric S.; DiBartola, Alex C.; Edmonson, Catherine; McIntyre, Lauren M.; Reller, L. Barth; Que, Yok-Ai; Ros, Robert; Lower, Brian H.; Fowler, Vance G.

    2011-01-01

    Medical implants, like cardiovascular devices, improve the quality of life for countless individuals but may become infected with bacteria like Staphylococcus aureus. Such infections take the form of a biofilm, a structured community of bacterial cells adherent to the surface of a solid substrate. Every biofilm begins with an attractive force or bond between bacterium and substratum. We used atomic force microscopy to probe experimentally forces between a fibronectin-coated surface (i.e., proxy for an implanted cardiac device) and fibronectin-binding receptors on the surface of individual living bacteria from each of 80 clinical isolates of S. aureus. These isolates originated from humans with infected cardiac devices (CDI; n = 26), uninfected cardiac devices (n = 20), and the anterior nares of asymptomatic subjects (n = 34). CDI isolates exhibited a distinct binding-force signature and had specific single amino acid polymorphisms in fibronectin-binding protein A corresponding to E652D, H782Q, and K786N. In silico molecular dynamics simulations demonstrate that residues D652, Q782, and N786 in fibronectin-binding protein A form extra hydrogen bonds with fibronectin, complementing the higher binding force and energy measured by atomic force microscopy for the CDI isolates. This study is significant, because it links pathogenic bacteria biofilms from the length scale of bonds acting across a nanometer-scale space to the clinical presentation of disease at the human dimension. PMID:22025727

  2. Impact of fibronectin fragments on the transendothelial migration of HIV-infected leukocytes and the development of subendothelial foci of infectious leukocytes.

    PubMed

    Birdsall, Holly H; Porter, Wendy J; Green, David M; Rubio, Jose; Trial, JoAnn; Rossen, Roger D

    2004-08-15

    Leukocyte infiltrates that can serve as viral reservoirs, and sites for viral replication are found in many organs of HIV-1-infected patients. Patients whose blood leukocytes migrate across confluent endothelial monolayers ex vivo and transmit infectious virus to mononuclear leukocytes (MNLs) lodged beneath this endothelial barrier have a worse prognosis. We evaluated the ability of 110- to 120-kDa fibronectin fragments (FNf), which are found in the blood of >60% of HIV-1-infected patients, to stimulate transendothelial migration and drive productively infected MNLs into a potential perivascular space. FNf induced MNLs to release TNF-alpha in a dose-dependent fashion; the resulting increase in lymphocyte and monocyte transendothelial migration could be blocked with soluble TNF receptor I. Rather than penetrate deeply into the subendothelial matrix, as is seen with untreated controls, FNf-treated MNLs clustered just below the endothelial monolayer. Treatment with FNf during migration increased subsequent recovery of HIV-infected cells from the subendothelial compartment. FNf treatment also significantly increased the numbers of HLA-DR(bright), dendritic-type cells that reverse-migrated from the subendothelial depot to the apical endothelial surface 48 h after migration. Fibronectin fragments can be produced by viral and host proteases in the course of inflammatory conditions. The ability of FNf to stimulate transendothelial migration of HIV-1-infected MNLs may help to explain the dissemination of this infection into cardiac, renal, and CNS tissues. PMID:15294993

  3. klf2a couples mechanotransduction and zebrafish valve morphogenesis through fibronectin synthesis

    PubMed Central

    Steed, Emily; Faggianelli, Nathalie; Roth, Stéphane; Ramspacher, Caroline; Concordet, Jean-Paul; Vermot, Julien

    2016-01-01

    The heartbeat and blood flow signal to endocardial cell progenitors through mechanosensitive proteins that modulate the genetic program controlling heart valve morphogenesis. To date, the mechanism by which mechanical forces coordinate tissue morphogenesis is poorly understood. Here we use high-resolution imaging to uncover the coordinated cell behaviours leading to heart valve formation. We find that heart valves originate from progenitors located in the ventricle and atrium that generate the valve leaflets through a coordinated set of endocardial tissue movements. Gene profiling analyses and live imaging reveal that this reorganization is dependent on extracellular matrix proteins, in particular on the expression of fibronectin1b. We show that blood flow and klf2a, a major endocardial flow-responsive gene, control these cell behaviours and fibronectin1b synthesis. Our results uncover a unique multicellular layering process leading to leaflet formation and demonstrate that endocardial mechanotransduction and valve morphogenesis are coupled via cellular rearrangements mediated by fibronectin synthesis. PMID:27221222

  4. Clinical studies on plasma fibronectin and factor XIII; with special reference to hyperlipoproteinemia.

    PubMed

    Cucuianu, M; Rus, H G; Cristea, A; Niculescu, F; Bedeleanu, D; Poruţiu, D; Roman, S

    1985-04-30

    When compared to age-matched normal weight normolipidemic control subjects, plasma factor XIII, plasma fibronectin and serum cholinesterase levels were found to be markedly decreased in patients with decompensated cirrhosis of the liver, not significantly changed in hyperlipoproteinemia type IIa (heterozygous subjects) and increased in hypertriglyceridemic subjects (type IIb and IV) as well as in hyperlipidemic nephrotic patients. A possible accelerated hepatic synthesis of certain plasma proteins including factor XIII and fibronectin in patients with the nephrotic syndrome as well as in endogenous hypertriglyceridemia is envisaged. It is also considered that mural thrombi, richer in factor XIII and fibronectin, would be more resistant to fibrinolysis and more readily attached to subendothelial structures. PMID:3922652

  5. Single-molecule dynamic force spectroscopy of the fibronectin-heparin interaction

    SciTech Connect

    Mitchell, Gabriel; Lamontagne, Charles-Antoine; Lebel, Rejean; Grandbois, Michel Malouin, Francois

    2007-12-21

    The integrity of cohesive tissues strongly depends on the presence of the extracellular matrix, which provides support and anchorage for cells. The fibronectin protein and the heparin-like glycosaminoglycans are key components of this dynamic structural network. In this report, atomic force spectroscopy was used to gain insight into the compliance and the resistance of the fibronectin-heparin interaction. We found that this interaction can be described by an energetic barrier width of 3.1 {+-} 0.2 A and an off-rate of 0.2 {+-} 0.1 s{sup -1}. These dissociation parameters are similar to those of other carbohydrate-protein interactions and to off-rate values reported for more complex interactions between cells and extracellular matrix components. Our results indicate that the function of the fibronectin-heparin interaction is supported by its capacity to sustain significant deformations and considerable external mechanical forces.

  6. Nucleotide sequence analysis of the DNA binding region of the chicken fibronectin gene.

    PubMed

    Karasaki, Y; Gotoh, S; Kubomura, S; Higashi, K; Hirano, H

    1988-12-01

    We have determined the nucleotide sequence of 2.0 kb EcoRI segment from the clone lambda FC32 of the genomic chicken fibronectin gene, which is called DNA binding domain. This segment overlapped another clone lambda FC36 and contained three exons which were 16, 17 and 18. They were classified as Type III repeat as originally shown in bovine plasma fibronectin. The average homologies of these three exons among the chicken, rat and human fibronectins in amino acid level are very high (87-98%) compared with that (79-88%) of the exons in the cell binding domain, indicating that this region is highly conservative during the evolution. PMID:3212295

  7. Large format focal plane array integration with precision alignment, metrology and accuracy capabilities

    NASA Astrophysics Data System (ADS)

    Neumann, Jay; Parlato, Russell; Tracy, Gregory; Randolph, Max

    2015-09-01

    Focal plane alignment for large format arrays and faster optical systems require enhanced precision methodology and stability over temperature. The increase in focal plane array size continues to drive the alignment capability. Depending on the optical system, the focal plane flatness of less than 25μm (.001") is required over transition temperatures from ambient to cooled operating temperatures. The focal plane flatness requirement must also be maintained in airborne or launch vibration environments. This paper addresses the challenge of the detector integration into the focal plane module and housing assemblies, the methodology to reduce error terms during integration and the evaluation of thermal effects. The driving factors influencing the alignment accuracy include: datum transfers, material effects over temperature, alignment stability over test, adjustment precision and traceability to NIST standard. The FPA module design and alignment methodology reduces the error terms by minimizing the measurement transfers to the housing. In the design, the proper material selection requires matched coefficient of expansion materials minimizes both the physical shift over temperature as well as lowering the stress induced into the detector. When required, the co-registration of focal planes and filters can achieve submicron relative positioning by applying precision equipment, interferometry and piezoelectric positioning stages. All measurements and characterizations maintain traceability to NIST standards. The metrology characterizes the equipment's accuracy, repeatability and precision of the measurements.

  8. Potential regulation of cartilage metabolism in osteoarthritis by fibronectin fragments.

    PubMed

    Homandberg, G A

    1999-10-15

    There are few candidates for biochemical pathways that either initiate or amplify catabolic processes involved in osteoarthritis (OA). Perhaps, one of the most likely sources for such pathways may be within the extracellular matrix itself. This review focuses on an example of how specific degradation products of the extracellular matrix of cartilage, produced during proteolytic damage, have the potential to enhance OA-like processes. In this example, these products can induce or activate other factors, such as catabolic cytokines, that amplify the damage. The damage, in turn, enhances levels of the degradation products themselves, as in a positive feedback loop. Since these products are derived from the cartilage matrix, they could be considered barometers of the health of the cartilage that signal to the chondrocyte, through outside to inside signaling, the health or status of the surrounding matrix. The best example and most characterized system is that of fragments of the matrix protein, fibronectin (Fn), although as discussed later, other recently discovered fragment systems may also have the potential to regulate cartilage metabolism. In the case of Fn fragments (Fn-fs), the Fn-fs enhance levels of catabolic cytokines as in OA and, thus, are potentially earlier damage mediators than catabolic cytokines. The Fn-fs up-regulate matrix metalloproteinase (MMP) expression, significantly enhance degradation and loss of proteoglycan (PG) from cartilage and temporarily suppress PG synthesis, all events observed in OA. However, this Fn-f system may be involved in normal cartilage homeostasis as well. For example, low concentrations of Fn-fs enhance anabolic activities and could play a role in normal homeostasis. This system may also be involved in not only amplifying damage but also coupling damage to repair. For example, high concentrations of Fn-fs that might arise in OA temporarily offset the anabolic response of lower Fn-f concentrations and cause short

  9. Fibronectin Terminated Multilayer Films: Protein Adsorption and Cell Attachment Studies

    PubMed Central

    Wittmer, Corinne R.; Phelps, Jennifer A.; Saltzman, W. Mark; Van Tassel, Paul R.

    2006-01-01

    Electrostatically driven layer-by-layer (LbL) assembly is a simple and robust method for producing structurally tailored thin film biomaterials, of thickness ca. 10 nanometers, containing biofunctional ligands. We investigate the LbL formation of multilayer films composed of polymers of biological origin (poly(L-lysine) (PLL) and dextran sulfate (DS)), the adsorption of fibronectin (Fn) - a matrix protein known to promote cell adhesion - onto these films, and the subsequent spreading behavior of human umbilical vein endothelial cells (HUVEC). We employ optical waveguide lightmode spectroscopy (OWLS) and quartz crystal microgravimetry with dissipation (QCMD) to characterize multilayer assembly in situ, and find adsorbed Fn mass on PLL terminated films to exceed that on DS terminated films by 40%, correlating with the positive charge and lower degree of hydration of PLL terminated films. The extent and initial rate of Fn adsorption to both PLL and DS terminated films exceed those onto the bare substrate, indicating the important role of electrostatic complexation between negatively charged protein and positively charged PLL at or near the film surface. We use phase contrast optical microscopy to investigate the time dependent morphological changes of HUVEC as a function of layer number, charge of terminal layer, and the presence of Fn. We observe HUVEC to attach, spread, and lose circularity on all surfaces. (Positively charged) PLL terminated films exhibit a greater extent of cell spreading than do (negatively charged) DS terminated films, and spreading is enhanced while circularity loss is suppressed by the presence of adsorbed Fn. The number of layers plays a significant role only for DS terminated films with Fn, where spreading on a bilayer greatly exceeds that on a multilayer, and PLL terminated films without Fn, where initial spreading is significantly higher on a monolayer. We observe initial cell spreading to be followed by retraction (i.e. decreased cell

  10. Cellular fibronectin response to supervised moderate aerobic training in patients with type 2 diabetes

    PubMed Central

    Alghadir, Ahmad H.; Gabr, Sami A.; Al-Eisa, Einas

    2016-01-01

    [Purpose] Physical activity is one of the most pivotal targets for the prevention and management of vascular complications, especially endothelial dysfunctions. Cellular fibronectin is an endothelium-derived protein involved in subendothelial matrix assembly. Its plasma levels reflect matrix alterations and vessel wall destruction in patients with type II diabetes. This study investigated the influence of 12 weeks of supervised aerobic training on cellular fibronectin and its relationship with insulin resistance and body weight in type II diabetic subjects. [Subjects and Methods] This study included 50 men with type II diabetes who had a mean age of 48.8 ± 14.6 years and were randomly divided into two groups: an aerobic exercise group (12 weeks, three 50 minutes sessions per week) and control group. To examine changes in cellular fibronectin, glycosylated hemoglobin, insulin resistance, fasting insulin, fasting blood sugar, and lipid profile, 5 ml of blood was taken from the brachial vein of patients before and 48 hours after completion of the exercise period and after 12 hours of fasting at rest. Data analysis was performed using the SPSS-16 software with the independent and paired t-tests. [Results] A significant decrease was observed in body mass index and body fat percentage in the experimental group. Compared with the control group, the aerobic exercise group showed a significant decrease in cellular fibronectin, glycosylated hemoglobin, insulin resistance, fasting insulin, fasting blood sugar, and lipid profile after 12 weeks of aerobic exercise. The change in cellular fibronectin showed positive significant correlation with body mass index, diabetic biomarkers, and physical activity level. [Conclusion] The results showed that supervised aerobic exercise as a stimulus can change the levels of cellular fibronectin as matrix metalloproteinase protein a long with improvement of insulin sensitivity and glycosylated hemoglobin in order to prevent

  11. Cellular fibronectin response to supervised moderate aerobic training in patients with type 2 diabetes.

    PubMed

    Alghadir, Ahmad H; Gabr, Sami A; Al-Eisa, Einas

    2016-04-01

    [Purpose] Physical activity is one of the most pivotal targets for the prevention and management of vascular complications, especially endothelial dysfunctions. Cellular fibronectin is an endothelium-derived protein involved in subendothelial matrix assembly. Its plasma levels reflect matrix alterations and vessel wall destruction in patients with type II diabetes. This study investigated the influence of 12 weeks of supervised aerobic training on cellular fibronectin and its relationship with insulin resistance and body weight in type II diabetic subjects. [Subjects and Methods] This study included 50 men with type II diabetes who had a mean age of 48.8 ± 14.6 years and were randomly divided into two groups: an aerobic exercise group (12 weeks, three 50 minutes sessions per week) and control group. To examine changes in cellular fibronectin, glycosylated hemoglobin, insulin resistance, fasting insulin, fasting blood sugar, and lipid profile, 5 ml of blood was taken from the brachial vein of patients before and 48 hours after completion of the exercise period and after 12 hours of fasting at rest. Data analysis was performed using the SPSS-16 software with the independent and paired t-tests. [Results] A significant decrease was observed in body mass index and body fat percentage in the experimental group. Compared with the control group, the aerobic exercise group showed a significant decrease in cellular fibronectin, glycosylated hemoglobin, insulin resistance, fasting insulin, fasting blood sugar, and lipid profile after 12 weeks of aerobic exercise. The change in cellular fibronectin showed positive significant correlation with body mass index, diabetic biomarkers, and physical activity level. [Conclusion] The results showed that supervised aerobic exercise as a stimulus can change the levels of cellular fibronectin as matrix metalloproteinase protein a long with improvement of insulin sensitivity and glycosylated hemoglobin in order to prevent

  12. Heterologously Expressed Staphylococcus aureus Fibronectin-Binding Proteins Are Sufficient for Invasion of Host Cells

    PubMed Central

    Sinha, Bhanu; Francois, Patrice; Que, Yok-Ai; Hussain, Muzaffar; Heilmann, Christine; Moreillon, Philippe; Lew, Daniel; Krause, Karl-Heinz; Peters, Georg; Herrmann, Mathias

    2000-01-01

    Staphylococcus aureus invasion of mammalian cells, including epithelial, endothelial, and fibroblastic cells, critically depends on fibronectin bridging between S. aureus fibronectin-binding proteins (FnBPs) and the host fibronectin receptor integrin α5β1 (B. Sinha et al., Cell. Microbiol. 1:101–117, 1999). However, it is unknown whether this mechanism is sufficient for S. aureus invasion. To address this question, various S. aureus adhesins (FnBPA, FnBPB, and clumping factor [ClfA]) were expressed in Staphylococcus carnosus and Lactococcus lactis subsp. cremoris. Both noninvasive gram-positive microorganisms are genetically distinct from S. aureus, lack any known S. aureus surface protein, and do not bind fibronectin. Transformants of S. carnosus and L. lactis harboring plasmids coding for various S. aureus surface proteins (FnBPA, FnBPB, and ClfA) functionally expressed adhesins (as determined by bacterial clumping in plasma, specific latex agglutination, Western ligand blotting, and binding to immobilized and soluble fibronectin). FnBPA or FnBPB but not of ClfA conferred invasiveness to S. carnosus and L. lactis. Invasion of 293 cells by transformants was comparable to that of strongly invasive S. aureus strain Cowan 1. Binding of soluble and immobilized fibronectin paralleled invasiveness, demonstrating that the amount of accessible surface FnBPs is rate limiting. Thus, S. aureus FnBPs confer invasiveness to noninvasive, apathogenic gram-positive cocci. Furthermore, FnBP-coated polystyrene beads were internalized by 293 cells, demonstrating that FnBPs are sufficient for invasion of host cells without the need for (S. aureus-specific) coreceptors. PMID:11083807

  13. Lectins as probes for assessing the accessibility of N-linked glycans in relation to the conformational changes of fibronectin.

    PubMed

    Agniel, Rémy; Vendrely, Charlotte; Poulouin, Laurent; Bascetin, Rümeyza; Benachour, Hamanou; Gallet, Olivier; Leroy-Dudal, Johanne

    2015-12-01

    Fibronectin, a ≈ 450-kDa protein with 4-9% (w/w) glycosylation, is a key component of extracellular matrices and has a high conformational lability regarding its functions. However, the accessibility and the role of glycosylated moieties associated with the conformational changes of fibronectin are poorly understood. Using lectins as probes, we developed an approach comprising dynamic light scattering, turbidimetry measurements, and isothermal titration calorimetry to assess the accessibility of glycosylated moieties of fibronectin undergoing thermal-induced conformational changes. Among a set of 14 lectins, fibronectin mainly reacted with mannose-binding lectins, specifically concanavalin A. When temperature was raised from 25 to 50 °C, fibronectin underwent progressive unfolding, but the conformation of concanavalin A was unaffected. Dynamic light scattering, turbidimetry measurements, and isothermal titration calorimetry showed increased concanavalin A binding to fibronectin during progressive thermal-induced unfolding of the protein core. Such data suggest that mannosylated residues are progressively exposed as fibronectin unfolds. Because oligosaccharide moieties can be differently exposed to cells, and the cell's responses could be modified physiologically or pathologically, modulation of fibronectin sugar chains could be relevant to its biological functions. Thus, lectins might be useful tools to probe the glycosylation accessibility accompanying changes in protein core folding, for which a better understanding would be of value for biological and biomedical research. PMID:26148749

  14. REGULATION OF p38 MAP KINASE BY ANASTELLIN IS INDEPENDENT OF ANASTELLIN’S EFFECT ON MATRIX FIBRONECTIN

    PubMed Central

    You, Ran; Klein, R. Matthew; Zheng, Mingzhe; McKeown-Longo, Paula J.

    2009-01-01

    Anastellin is an angiogenesis inhibitor derived from the first type III repeat of fibronectin (FN). Anastellin binds to fibronectin and promotes the polymerization of soluble fibronectin into a highly polymerized form termed superfibronectin. In addition, anastellin also causes remodeling of pre-existing fibronectin matrix and modulates cell signaling pathways in both endothelial cells and fibroblasts. In the present study, we address the relationship of anastellin’s effects on fibronectin matrix to its effects on p38 MAP kinase (MAPK) activation. Using a mutant form of anastellin which binds to fibronectin matrix, but does not stimulate formation of superfibronectin, we demonstrate that the activation of p38 MAPK by anastellin is not dependent on the formation of superfibronectin. The mutant form of anastellin does stimulate matrix remodeling, but experiments using FN−/− cells show that the effect of anastellin on p38-MAPK activation is completely independent of fibronectin. Anastellin was able to activate p38 MAPK on cells in suspension as well as on cells null for β1 integrins, suggesting that anastellin activity did not require ligation of integrins. These data suggest that the activation of p38 MAPK by anastellin is independent of anastellin’s effects on fibronectin matrix organization. PMID:19379667

  15. Mislocalized Scaffolding by the Na-H Exchanger NHE1 Dominantly Inhibits Fibronectin Production and TGF-β Activation

    PubMed Central

    Karydis, Anastasios; Jimenez-Vidal, Maite; Denker, Sheryl P.

    2009-01-01

    Secretion and assembly of the extracellular matrix protein fibronectin regulates a number of normal cell and tissue functions and is dysregulated in disease states such as fibrosis, diabetes, and cancer. We found that mislocalized scaffolding by the plasma membrane Na-H exchanger NHE1 suppresses fibronectin expression, secretion, and assembly. In fibroblasts, wild-type NHE1 localizes to the distal margin of membrane protrusions or lamellipodia but a mutant NHE1-KRA2 lacking binding sites for PI(4,5)P2 and the ERM proteins ezrin, radixin, and moesin is mislocalized and found uniformly along the plasma membrane. Although NHE1 regulates intracellular pH homeostasis, fibronectin production is not regulated by changes in intracellular pH, nor is it attenuated in NHE1-deficient cells, indicating fibronectin expression is independent of NHE1 activity. However, fibronectin production is nearly absent in cells expressing NHE1-KRA2 because scaffolding by NHE1 is mislocalized. Additionally, secretion of active but not latent TGF-β is reduced and exogenous TGF-β restores fibronectin secretion and assembly. Our data indicate that scaffolding by NHE1-KRA2 dominantly suppresses fibronectin synthesis and TGF-β activation, and they suggest that NHE1-KRA2 can be used for obtaining a mechanistic understanding of how fibronectin production is regulated and speculatively for therapeutic control of dysregulated production in pathological conditions. PMID:19225158

  16. SNAP Satellite Focal Plane Development

    SciTech Connect

    Bebek, C.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bercovitz, J.; Bergstrom, L.; Berstein, G.P.; Bester, M.; Bohlin, R.; Bonissent, A.; Bower, C.; Campbell, M.; Carithers, W.; Commins, E.; Day, C.; Deustua, S.; DiGennaro, R.; Ealet, A.; Ellis, R.; Emmett, W.; Eriksson, M.; Fouchez,D.; Fruchter, A.; Genat, J-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Holland, S.; Huterer, D.; Johnson, W.; Kadel, R.; Karcher,A.; Kim, A.; Kolbe, W.; Lafever, R.; Lamoureaux, J.; Lampton, M.; Lefevre, O.; Levi, M.; Levin, D.; Linder, E.; Loken, S.; Malina, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Roe, N.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Prieto, E.; Rabinowitz,D.; Refregier, A.; Rhodes, J.; Schubnell, M.; Sholl, M.; Smadja, G.; Smith, R.; Smoot, G.; Snyder, J.; Spadafora, A.; Szymkowiak, A.; Tarle,G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.

    2003-07-07

    The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to advance our preparedness for mission proposal in the areas of detectors and electronics.

  17. Design of an Osteoinductive Extracellular Fibronectin Matrix Protein for Bone Tissue Engineering

    PubMed Central

    Lee, Sujin; Lee, Dong-Sung; Choi, Ilsan; Pham, Le B. Hang; Jang, Jun-Hyeog

    2015-01-01

    Integrin-mediated cell-matrix interactions play an important role in osteogenesis. Here, we constructed a novel osteoinductive fibronectin matrix protein (oFN) for bone tissue engineering, designed to combine the integrin-binding modules from fibronectin (iFN) and a strong osteoinductive growth factor, bone morphogenetic protein-2. Compared with iFN, the purified oFN matrix protein caused a significant increase in cell adhesion and osteogenic differentiation of pre-osteoblast MC3T3-E1 cells (p < 0.05). PMID:25853265

  18. Frcp1 and Frcp2, two novel fibronectin type III repeat containing genes.

    PubMed

    Teufel, Andreas; Malik, Nasir; Mukhopadhyay, Mahua; Westphal, Heiner

    2002-09-01

    The fibronectin type III (FNIII) repeat is one of three structural motifs originally identified in the fibronectin protein and has been well characterized in recent years. The consensus sequence has since been found in many different proteins including receptors and cell adhesion molecules. We report the cloning and expression analysis of Frcp1 and Frcp2, two members of a new FNIII repeat containing gene family. During embryonic development both genes are primarily expressed in the brain. In adult tissues, Frcp1 is strongly expressed in the liver and Frcp2 in the heart. PMID:12384288

  19. Expression of DFak56, a Drosophila homolog of vertebrate focal adhesion kinase, supports a role in cell migration in vivo

    PubMed Central

    Fox, George L.; Rebay, Ilaria; Hynes, Richard O.

    1999-01-01

    Focal adhesion kinase (FAK) is a highly conserved, cytoplasmic tyrosine kinase that has been implicated in promoting cell migration and transmission of antiapoptotic signals in vertebrate cells. In cultured cells, integrin engagement with the extracellular matrix promotes the recruitment of FAK to focal contacts and increases in its phosphotyrosine content and kinase activity, suggesting FAK is an intracellular mediator of integrin signaling. We have identified a Drosophila FAK homolog, DFak56, that is 33% identical to vertebrate FAK, with the highest degree of homology in domains critical for FAK function, including the kinase and focal adhesion targeting domains, and several protein–protein interaction motifs. Furthermore, when expressed in NIH 3T3 cells, DFak56 both localizes to focal contacts and displays the characteristic elevation of phosphotyrosine content in response to plating the cells on fibronectin. During embryogenesis, DFak56 is broadly expressed, and it becomes elevated in the gut and central nervous system at later stages. Consistent with a role in cell migration, we also observe that DFak56 is abundant in the border cells of developing egg chambers before the onset of, and during, their migration. PMID:10611323

  20. Supporting prostate cancer focal therapy: a multidisciplinary International Consensus of Experts ("ICE").

    PubMed

    Reis, Leonardo O; Billis, Athanase; Zequi, Stenio C; Tobias-Machado, Marcos; Viana, Publio; Cerqueira, Michael; Ward, John F

    2014-06-01

    Prostate cancer is a common malignancy among men, and the current screening, imaging and sampling approaches aim to detect early-stage, organ-confined disease. In such scenario, focal prostate cancer therapy currently relies on the index lesion concept as the dominant lesion that drives the disease natural history. Focal therapy demands the essential imaging and sampling techniques to strategically locate and qualify the disease, but, despite advances in technology, prostate imaging and biopsy have several limitations that need to be overcome if focal therapy is to be developed further. The I Prostate Cancer Focal Treatment International Symposium was convened to foster discussion on this topic that sits at the crossroads of multiple disciplines (Urology, Pathology, Radiology, Radiation Oncology and Medical Oncology) all of which were represented for this comprehensive multidisciplinary review of the current literature. PMID:24597940

  1. Focal plane detectors for the WISE 12- and 23-μm bands

    NASA Astrophysics Data System (ADS)

    Hogue, H. H.; Mattson, R. B.; Stapelbroek, M. G.; Masterjohn, S. A.; Larsen, M. F.; Elwell, J. D.

    2007-09-01

    DRS Sensors & Targeting Systems, under contract to the Space Dynamics Laboratory of Utah State University, is providing the focal plane detector system for NASA's Wide-field Infrared Survey Explorer (WISE). The focal plane detector system consists of two mercury cadmium telluride (MCT) focal plane module assemblies (FPMAs), two arsenic doped silicon (Si:As) Blocked Impurity Band (BIB) FPMAs, electronics to drive the FPMAs and report digital data from them, and the cryogenic and ambient temperature cabling that connect the FPMAs and electronics. The MCT and Si:As BIB focal plane arrays (FPAs) utilized in the WISE FPMAs are both megapixel class indium-bump hybridized devices fabricated by Teledyne Imaging Systems and DRS Sensors & Targeting Systems, respectively. This paper reports performance of the WISE Si:As BIB FPAs that are used for the WISE 12- and 23-μm wavelength bands.

  2. Hemodynamics of focal choroidal excavations.

    PubMed

    Soma, Ryoko; Moriyama, Muka; Ohno-Matsui, Kyoko

    2015-04-01

    The purpose of this study was to investigate the hemodynamics of focal choroidal excavations (FCEs). Four eyes of four patients with a FCE were studied. Indocyanine green angiography (ICGA), laser speckle flowgraphy (LSFG), optical coherence tomography (OCT), and multi-focal electroretinography (mfERG) were performed to investigate the choroidal hemodynamics and the morphological and functional changes. The mean depth of the FCE determined by OCT was 222.5 ± 49.5 μm with a range of 164-272 μm. In one case, subretinal fluid was observed in the excavation, and in three cases, subretinal fluid was not observed. ICGA showed hypofluorescence, and laser flowgraphy (LSFG) showed decreased choroidal blood flow at the excavation in all cases. Three cases were symptomatic, and the amplitudes of the mfERGs were reduced. FCEs cause a decrease of choroidal blood flow. In three of four cases, the mfERGs were depressed over the FCEs leading to symptoms. PMID:25626897

  3. Rewritable photochromic focal plane masks

    NASA Astrophysics Data System (ADS)

    Molinari, Emilio; Bertarelli, Chiara; Bianco, Andrea; Bortoletto, Fabio; Conconi, Paolo; Crimi, Giuseppe; Gallazzi, Maria C.; Giro, Enrico; Lucotti, Andrea; Pernechele, Claudio; Zerbi, Filippo M.; Zerbi, Giuseppe

    2003-02-01

    The application of organic photochromic materials in astronomy is opening new possibilities which we are investigating in order to design innovative devices for future instrumentation. The photochromic property of transparent/opaque transition (although in a limited wavelength range) and the changes in intrinsic refractive index have led our studies to application in astronomic spectrographs, both as focal plane mask (for MOS application) and as dispersive elements (volume phase holographic gratings, VPHG), respectively. In both cases the possibility to write and erase devices with suitable irradiation has revealed a new perspective for non-disposable and fully customizable items for spectroscopy. Pursuing this goal we have synthesized a series of novel photochromic materials belonging to the diarylethenes. They fulfill the requirements of thermal stability and fatigue resistance necessary to build functional devices. Prototypes of high contrast focal plane mask working in the H-alpha spectral region have been manufactured and characterized both in laboratory and with the AFOSC camera at Asiago telescope (1.8 m). A custom writing robot (ARATRO) which, taking imaging frames and with the aid of interactive mask design software and ad hoc control electronics, is able to write MOS masks, has been constructed. The design of the MOS masks allow the fitting in the AFOSC slit wheel. The overall set-up is ready for the sky tests.

  4. Implementation of focal zooming on the Nike KrF laser.

    PubMed

    Kehne, D M; Karasik, M; Aglitsky, Y; Smyth, Z; Terrell, S; Weaver, J L; Chan, Y; Lehmberg, R H; Obenschain, S P

    2013-01-01

    In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ = 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters. PMID:23387652

  5. Implementation of focal zooming on the Nike KrF laser

    NASA Astrophysics Data System (ADS)

    Kehne, D. M.; Karasik, M.; Aglitsky, Y.; Smyth, Z.; Terrell, S.; Weaver, J. L.; Chan, Y.; Lehmberg, R. H.; Obenschain, S. P.

    2013-01-01

    In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser (λ = 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 μm thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

  6. Implementation of focal zooming on the Nike KrF laser

    SciTech Connect

    Kehne, D. M.; Karasik, M.; Weaver, J. L.; Chan, Y.; Obenschain, S. P.; Aglitsky, Y.; Smyth, Z.; Lehmberg, R. H.; Terrell, S.

    2013-01-15

    In direct drive inertial confinement laser fusion, a pellet containing D-T fuel is imploded by ablation arising from absorption of laser energy at its outer surface. For optimal coupling, the focal spot of the laser would continuously decrease to match the reduction in the pellet's diameter, thereby minimizing wasted energy. A krypton-fluoride laser ({lambda}= 248 nm) that incorporates beam smoothing by induced spatial incoherence has the ability to produce a high quality focal profile whose diameter varies with time, a property known as focal zooming. A two-stage focal zoom has been demonstrated on the Nike laser at the Naval Research Laboratory. In the experiment, a 4.4 ns laser pulse was created in which the on-target focal spot diameter was 1.3 mm (full width at half maximum) for the first 2.4 ns and 0.28 mm for the final 2 ns. These two diameters appear in time-integrated focal plane equivalent images taken at several locations in the amplification chain. Eight of the zoomed output beams were overlapped on a 60 {mu}m thick planar polystyrene target. Time resolved images of self-emission from the rear of the target show the separate shocks launched by the two corresponding laser focal diameters.

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

    PubMed

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

    2010-11-01

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

  8. Mechanotransduction at focal adhesions: integrating cytoskeletal mechanics in migrating cells

    PubMed Central

    Kuo, Jean-Cheng

    2013-01-01

    Focal adhesions (FAs) are complex plasma membrane-associated macromolecular assemblies that serve to physically connect the actin cytoskeleton to integrins that engage with the surrounding extracellular matrix (ECM). FAs undergo maturation wherein they grow and change composition differentially to provide traction and to transduce the signals that drive cell migration, which is crucial to various biological processes, including development, wound healing and cancer metastasis. FA-related signalling networks dynamically modulate the strength of the linkage between integrin and actin and control the organization of the actin cytoskeleton. In this review, we have summarized a number of recent investigations exploring how FA composition is affected by the mechanical forces that transduce signalling networks to modulate cellular function and drive cell migration. Understanding the fundamental mechanisms of how force governs adhesion signalling provides insights that will allow the manipulation of cell migration and help to control migration-related human diseases. PMID:23551528

  9. Focal axis resolver for offset reflector antennas

    NASA Technical Reports Server (NTRS)

    Schmidt, R. F. (Inventor)

    1983-01-01

    Method and apparatus for determining the focal axis of an asymmetrical antenna such as an offset paraboloid reflector whose physical rim is not coincident with the boundary of the electrical aperture but whose focal point is known is provided. A transmitting feed horn array consisting of at least two feed horn elements is positioned asymmetrically on either side of an estimated focal axis which is generally inclined with respect to the boresight axis of the antenna. The feed horn array is aligned with the estimated focal axis so that the phase centers (CP sub 1, CP sub 2) of the two feed horn elements are located on a common line running through the focal point (F) orthogonally with respect to the estimated focal axis.

  10. Signal processing of microbolometer infrared focal-plane arrays

    NASA Astrophysics Data System (ADS)

    Zhang, Junju; Qian, Yunsheng; Chang, Benkang; Xing, Suxia; Sun, Lianjun

    2005-01-01

    A 320×240-uncooled-microbolometer-based signal processing circuit for infrared focal-plane arrays is presented, and the software designs of this circuit system are also discussed in details. This signal processing circuit comprises such devices as FPGA, D/A, A/D, SRAM, Flash, DSP, etc., among which, FPGA is the crucial part, which realizing the generation of drive signals for infrared focal-plane, nonuniformity correction, image enhancement and video composition. The device of DSP, mainly offering auxiliary functions, carries out communication with PC and loads data when power-up. The phase locked loops (PLL) is used to generate high-quality clocks with low phase dithering and multiple clocks are to used satisfy the demands of focal-plane arrays, A/D, D/A and FPGA. The alternate structure is used to read or write SRAM in order to avoid the contradiction between different modules. FIFO embedded in FPGA not only makes full use of the resources of FPGA but acts as the channel between different modules which have different-speed clocks. What's more, working conditions, working process, physical design and management of the circuit are discussed. In software designing, all the function modules realized by FPGA and DSP devices, which are mentioned in the previous part, are discussed explicitly. Particularly to the nonuniformity correction module, the pipeline structure is designed to improve the working frequency and the ability to realize more complex algorithm.

  11. Multiplicative and subtractive focal volume engineering in coherent Raman microscopy

    PubMed Central

    Raghunathan, Varun; Potma, Eric Olaf

    2012-01-01

    Rigorous calculations are performed to study the effective reduction of the nonlinear excitation volumes when using phase-only masks to condition the pump and Stokes driving fields. Focal volume reduction was achieved using both a multiplicative operation of the excitation fields as well as a subtractive operation. Using a tunable optical bottle beam for the Stokes field, an effective reduction of the width of the excitation volume by a factor of 1.5 can be achieved in the focal plane. Further reduction of the focal volume introduces a rapid growth of sidelobes, which renders such volumes unsuitable for imaging applications. In addition, phase sensitive detection was found to provide information from selective sub-divisions of the engineered coherent anti-Stokes Raman scattering excitation volume. In the case of isolated nanoparticles, an apparent resolution improvement by a factor of 3 is demonstrated, and it is shown that the size of sub-diffraction-limited particles can be accurately determined using phase sensitive detection. PMID:21045900

  12. Functional Analysis of an S-Layer-Associated Fibronectin-Binding Protein in Lactobacillus acidophilus NCFM

    PubMed Central

    Hymes, Jeffrey P.; Johnson, Brant R.; Barrangou, Rodolphe

    2016-01-01

    Bacterial surface layers (S-layers) are crystalline arrays of self-assembling proteinaceous subunits called S-layer proteins (Slps) that comprise the outermost layer of the cell envelope. Many additional proteins that are associated with or embedded within the S-layer have been identified in Lactobacillus acidophilus NCFM, an S-layer-forming bacterium that is widely used in fermented dairy products and probiotic supplements. One putative S-layer-associated protein (SLAP), LBA0191, was predicted to mediate adhesion to fibronectin based on the in silico detection of a fibronectin-binding domain. Fibronectin is a major component of the extracellular matrix (ECM) of intestinal epithelial cells. Adhesion to intestinal epithelial cells is considered an important trait for probiotic microorganisms during transit and potential association with the intestinal mucosa. To investigate the functional role of LBA0191 (designated FbpB) in L. acidophilus NCFM, an fbpB-deficient strain was constructed. The L. acidophilus mutant with a deletion of fbpB lost the ability to adhere to mucin and fibronectin in vitro. Homologues of fbpB were identified in five additional putative S-layer-forming species, but no homologues were detected in species outside the L. acidophilus homology group. PMID:26921419

  13. Tenascin variants: differential binding to fibronectin and distinct distribution in cell cultures and tissues.

    PubMed Central

    Chiquet-Ehrismann, R; Matsuoka, Y; Hofer, U; Spring, J; Bernasconi, C; Chiquet, M

    1991-01-01

    In the chicken, three tenascin variants have been characterized that are generated by alternative splicing of 3 of its 11 fibronectin type III repeats. Using monoclonal antibodies that react with common regions versus extra repeats of tenascin, we could distinguish and separate tenascin variants and investigate their interaction with fibronectin using multiple experimental procedures. Interestingly, in all assays used the smallest tenascin variant bound more strongly to fibronectin than the larger ones. These biochemical data were paralleled by the observation that in chick embryo fibroblast cultures only the smallest form of tenascin could be detected in the fibronectin-rich extracellular matrix network laid down by the cells. Furthermore, each tissue present in adult chicken gizzard contained a distinct set of tenascin variants. Those tissues particularly rich in extracellular matrix, such as the tendon, contained the smallest tenascin only. Intermediate-sized tenascin was present in smooth muscle, whereas the largest form was exclusively detectable underneath the epithelial lining of the villi. Thus it appears that cell type-specific forms of tenascin exist that are appropriate for the functional requirements of the respective extracellular matrices. Images PMID:1725601

  14. Modification of shear modulus and creep compliance of fibrin clots by fibronectin.

    PubMed

    Kamykowski, G W; Mosher, D F; Lorand, L; Ferry, J D

    1981-02-01

    Shear moduli and creep compliances have been measured for four types of clots of human fibrin (about 7 mg/ml) clotted with and without human plasma fibronectin (usually 1.2 mg/ml). Fine clots (with little lateral aggregation of the fibrin protofibrils) were found at pH 8.5, ionic strength 0.45; coarse clots (with substantial lateral aggregation) were formed at pH 7.5, ionic strength 0.15; in both cases with and without ligation by fibrinoligase. In fine clots, the addition of fibronectin without ligation scarcely affected the shear modulus; with ligation, the modulus was decreased by a factor of 0.48. In coarse clots, the shear modulus was increased by addition of fibronectin. The increase was by a factor of 2.0 without ligation and by a factor of 2.4 with ligation. Creep and creep recovery in clots formed with and without fibronectin were similar except for the scale factor represented by the change in modulus. PMID:7260326

  15. Upregulation of fibronectin expression by COX-2 is mediated by interaction with ELMO1.

    PubMed

    Yang, Chen; Sorokin, Andrey

    2011-01-01

    Engulfment and cell motility 1 (ELMO1), a bipartite guanine nucleotide exchange factor (GEF) for the small GTPase Rac 1, was identified as a susceptibility gene for glomerular disease. Here, we reported that ELMO1 interacted with COX-2 in human mesangial cells. Furthermore, we identified ELMO1 as a posttranslational regulator of COX-2 activity. We demonstrated that COX-2 cyclooxygenase activity increased fibronectin promoter activity. The protein-protein interaction between ELMO1 and COX-2 increased the cyclooxygenase activity of COX-2 and, correspondingly, fibronectin expression. We also found that ET625, the dominant negative form of ELMO1 lacking Rac1 activity, interacted with COX-2, increased cyclooxygenase activity of COX-2 and enhanced COX-2-mediated fibronectin upregulation. To further rule out Rac1 as an ELMO1-mediated regulator of COX-2 activity, we employed the constitutive active Rac1, Rac1(Q63E), and demonstrated that Rac1 signaling has no effect on COX-2-mediated fibronectin promoter activity. These results suggest that ELMO1 contributes to the development of glomerular injury through serving as a regulator of COX-2 activity. The interaction of ELMO1 with COX-2 could play an important role in the development and progression of renal glomerular injury. PMID:20732417

  16. Fabrication of functional fibronectin patterns by nanosecond excimer laser direct write for tissue engineering applications.

    PubMed

    Grigorescu, S; Hindié, M; Axente, E; Carreiras, F; Anselme, K; Werckmann, J; Mihailescu, I N; Gallet, O

    2013-07-01

    Laser direct write techniques represent a prospective alternative for engineering a new generation of hybrid biomaterials via the creation of patterns consisting of biological proteins onto practically any type of substrate. In this paper we report on the characterization of fibronectin features obtained onto titanium substrates by UV nanosecond laser transfer. Fourier-transform infrared spectroscopy measurements evidenced no modification in the secondary structure of the post-transferred protein. The molecular weight of the transferred protein was identical to the initial fibronectin, no fragment bands being found in the transferred protein's Western blot migration profile. The presence of the cell-binding domain sequence and the mannose groups within the transferred molecules was revealed by anti-fibronectin monoclonal antibody immunolabelling and FITC-Concanavalin-A staining, respectively. The in vitro tests performed with MC3T3-E1 osteoblast-like cells and Swiss-3T3 fibroblasts showed that the cells' morphology and spreading were strongly influenced by the presence of the fibronectin spots. PMID:23615786

  17. Immunohistochemical demonstration of fibronectin in the most superficial layer of normal rabbit articular cartilage.

    PubMed Central

    Nishida, K; Inoue, H; Murakami, T

    1995-01-01

    OBJECTIVE--To locate fibronectin ultrastructurally in the most superficial layer of normal articular cartilage of rabbits, in order to clarify its role in joint physiology. METHODS--Articular cartilage was obtained from the femoral condyle of seven normal adult rabbits and prepared by a method that included tannic acid fixation. Polyclonal antibodies against rabbit fibronectin were used in an immunohistochemical electron microscopic study, without any enzymic digestion but with a pre-embedding method for the transmission electron microscopy. RESULTS--The cartilage surface was successfully preserved by tannic acid fixation. The most superficial layer in electron photomicrographs was approximately 200-300 nm thick, cell free, and appeared to have two parallel components: the more superficial lamina and the deeper lamina. Gold labelled fibronectin lined this layer in immunohistochemical electron photomicrographs. CONCLUSIONS--Fibronectin covering the surface of the articular cartilage may have a role in joint lubrication and protection of the cartilage by binding with the collagenous matrix and hyaluronic acid in synovial fluid. Chondroitin sulphates may act as a charge barrier in close relationship with the collagen fibrils in the deeper lamina. Significant alteration in these functions may be one of the first causal steps leading to destruction of the articular cartilage. Images PMID:8546534

  18. Beta 8 integrins mediate interactions of chick sensory neurons with laminin-1, collagen IV, and fibronectin.

    PubMed Central

    Venstrom, K; Reichardt, L

    1995-01-01

    Integrins are major receptors used by cells to interact with extracellular matrices. In this paper, we identify the first ligands for the beta 8 family of integrins, presenting evidence that integrin heterodimers containing the beta 8 subunit mediate interactions of chick sensory neurons with laminin-1, collagen IV, and fibronectin. A polyclonal antibody, anti-beta 8-Ex, was prepared to a bacterial fusion protein expressing an extracellular portion of the chicken beta 8 subunit. In nonreducing conditions, this antibody immunoprecipitated from surface-labeled embryonic dorsal root ganglia neurons a M(r) 100 k protein, the expected M(r) of the beta 8 subunit, and putative alpha subunit(s) of M(r) 120 k. Affinity-purified anti-beta 8-Ex strongly inhibited sensory neurite outgrowth on laminin-1, collagen IV, and fibronectin-coated substrata. Binding sites were identified in a heat-resistant domain in laminin-1 and in the carboxyl terminal, 40-kDa fibronectin fragment. On substrates coated with the carboxyl terminal fragment of fibronectin, antibodies to beta 1 and beta 8 were only partially effective alone, but were completely effective in combination, at inhibiting neurite outgrowth. Results thus indicate that the integrin beta 8 subunit in association with one or more alpha subunits forms an important set of extracellular matrix receptors on sensory neurons. Images PMID:7542940

  19. Focal axis resolver for offset reflector antennas

    NASA Technical Reports Server (NTRS)

    Schmidt, R. F.

    1980-01-01

    Described are electrical means for determining the focal axis of an offset reflector antenna whose physical rim is not coincident with the boundary of the electrical aperture. Even and odd sensing functions are employed in the focal region, leading to both amplitude and phase criteria for resolving a focal axis generally inclined with respect to the system axis. The analytical aspects of the problem are discussed, and an example related to a 4-meter Large-Antenna Multiple-Frequency Microwave Radiometer (LAMMR) is included. The technique is useful for focal axis determination in mathematical simulations and in the physical world.

  20. Digital scanner infrared focal plane technology

    NASA Astrophysics Data System (ADS)

    Ortiz, M. A.; Malone, N. R.; Harris, M.; Shin, J.; Byers, S.; Price, D.; Vampola, J.

    2011-09-01

    Advancements in finer geometry and technology advancements in circuit design now allow placement of digital architecture on cryogenic focal planes while using less power than heritage analog designs. These advances in technology reduce the size, weight, and power of modern focal planes. In addition, the interface to the focal plane is significantly simplified and is more immune to Electromagnetic Interference (EMI). The cost of the customer's instrument after integration with the digital scanning Focal Plane Array (FPA) has been significantly reduced by placing digital architecture such as Analog to digital convertors and Low Voltage Differential Signaling (LVDS) Inputs and Outputs (I/O) on the Read Out Integrated Circuit (ROIC).

  1. Neurocysticercosis presenting as focal hydrocephalus

    PubMed Central

    Malik, Azharuddin Mohammed; Shamim, Md Dilawez; Ahmad, Mehtab; Abdali, Nasar

    2014-01-01

    A 40-year-old man presented with a 2-month history of headache, nausea and vomiting, with generalised seizures for the past 15 days. On examination he had bilateral papilloedema, visual acuity was 6/6 in both eyes but perimetry showed right homonymous inferior quadrantanopia. His MRI showed numerous small cystic lesions with eccentric nodules, diffusely distributed in bilateral cerebral and cerebellar hemispheres. There was also focal hydrocephalus involving occipital and temporal horns of the left lateral ventricle leading to its selective dilation. Stool examination showed ova of Taenia solium. He was treated with albendazole, prednisone and sustained release sodium valproate for 1 month. His headache resolved and he is free of seizures. Repeat perimetry at 1 month also showed resolution of visual field defect. PMID:24962486

  2. Optimal focal-plane restoration

    NASA Technical Reports Server (NTRS)

    Reichenbach, Stephen E.; Park, Stephen K.

    1989-01-01

    Image restoration can be implemented efficiently by calculating the convolution of the digital image and a small kernel during image acquisition. Processing the image in the focal-plane in this way requires less computation than traditional Fourier-transform-based techniques such as the Wiener filter and constrained least-squares filter. Here, the values of the convolution kernel that yield the restoration with minimum expected mean-square error are determined using a frequency analysis of the end-to-end imaging system. This development accounts for constraints on the size and shape of the spatial kernel and all the components of the imaging system. Simulation results indicate the technique is effective and efficient.

  3. Regulation of the innate immune response by fibronectin: synergism between the III-1 and EDA domains.

    PubMed

    Kelsh, Rhiannon; You, Ran; Horzempa, Carol; Zheng, Mingzhe; McKeown-Longo, Paula J

    2014-01-01

    Fibronectin is a critical component of the extracellular matrix and alterations to its structure will influence cellular behavior. Matrix fibronectin is subjected to both mechanical and biochemical regulation. The Type III domains of fibronectin can be unfolded in response to increased cellular contractility, included or excluded from the molecule by alternative splicing mechanisms, or released from the matrix by proteolysis. Using Inflammatory Cytokine microarrays we found that the alternatively spliced fibronectin Type III domain, FnEDA, and the partially unfolded III-1 domain, FnIII-1c, induced the expression of a multitude of pro-inflammatory cytokines in human dermal fibroblasts, most notably CXCL1-3, IL-8 and TNF-α. FnIII-1c, a peptide representing an unfolded intermediate structure of the first Type III domain has been shown to initiate the toll-like receptor-4 (TLR4)-NFκB-dependent release of cytokines from human dermal fibroblasts (You, et al., J. Biol. Chem., 2010). Here we demonstrate that FnIII-1c and the alternatively spliced FnEDA domain induce a TLR4 dependent activation of p38 MAP kinase and its downstream effector, MAPKAP Kinase-2 (MK-2), to regulate cytokine expression in fibroblasts. RT-qPCR analysis indicated that the p38-MK-2 pathway regulates IL-8 mRNA stability. Interestingly, addition of FnIII-1c and FnEDA synergistically enhanced TLR4-dependent IL-8 release. These data indicate that Fn contains two Type III domains which can activate TLR signaling to induce an inflammatory response in fibroblasts. Furthermore, our data identifies the NF-κB and p38/MK2 signaling pathways as transducers of signals initiated in response to structural changes in fibronectin. PMID:25051083

  4. Regulation of the Innate Immune Response by Fibronectin: Synergism between the III-1 and EDA Domains

    PubMed Central

    Kelsh, Rhiannon; You, Ran; Horzempa, Carol; Zheng, Mingzhe; McKeown-Longo, Paula J.

    2014-01-01

    Fibronectin is a critical component of the extracellular matrix and alterations to its structure will influence cellular behavior. Matrix fibronectin is subjected to both mechanical and biochemical regulation. The Type III domains of fibronectin can be unfolded in response to increased cellular contractility, included or excluded from the molecule by alternative splicing mechanisms, or released from the matrix by proteolysis. Using Inflammatory Cytokine microarrays we found that the alternatively spliced fibronectin Type III domain, FnEDA, and the partially unfolded III-1 domain, FnIII-1c, induced the expression of a multitude of pro-inflammatory cytokines in human dermal fibroblasts, most notably CXCL1-3, IL-8 and TNF-α. FnIII-1c, a peptide representing an unfolded intermediate structure of the first Type III domain has been shown to initiate the toll-like receptor-4 (TLR4)-NFκB-dependent release of cytokines from human dermal fibroblasts (You, et al., J. Biol. Chem., 2010). Here we demonstrate that FnIII-1c and the alternatively spliced FnEDA domain induce a TLR4 dependent activation of p38 MAP kinase and its downstream effector, MAPKAP Kinase-2 (MK-2), to regulate cytokine expression in fibroblasts. RT-qPCR analysis indicated that the p38-MK-2 pathway regulates IL-8 mRNA stability. Interestingly, addition of FnIII-1c and FnEDA synergistically enhanced TLR4-dependent IL-8 release. These data indicate that Fn contains two Type III domains which can activate TLR signaling to induce an inflammatory response in fibroblasts. Furthermore, our data identifies the NF-κB and p38/MK2 signaling pathways as transducers of signals initiated in response to structural changes in fibronectin. PMID:25051083

  5. Structure and unfolding of the third type III domain from human fibronectin.

    PubMed

    Stine, Jessica M; Sun, Yizhi; Armstrong, Geoffrey; Bowler, Bruce E; Briknarová, Klára

    2015-11-10

    Fibronectin is a modular extracellular matrix protein that is essential for vertebrate development. The third type III domain (3FN3) in fibronectin interacts with other parts of fibronectin and with anastellin, a protein fragment that causes fibronectin aggregation. 3FN3 opens readily both as an isolated domain in solution and when part of fibronectin in stretched fibrils, and it was proposed that this opening is important for anastellin binding. We determined the structure of 3FN3 using nuclear magnetic resonance spectroscopy, and we investigated its stability, folding, and unfolding. Similar to most other FN3 domains, 3FN3 contains two antiparallel β-sheets that are composed of three (A, B, and E) and four (C, D, F, and G) β-strands, respectively, and are held together by a conserved hydrophobic interface. cis-trans isomerization of P847 at the end of β-strand C leads to observable conformational heterogeneity in 3FN3, with a cis peptide bond present in almost one-quarter of the molecules. The chemical stability of 3FN3 is relatively low, but the folding rate constant in the absence of denaturant is in the same range as those of other, more stable FN3 domains. Interestingly, the unfolding rate constant in the absence of denaturant is several orders of magnitude higher than the unfolding rate constants of other FN3 domains investigated to date. This unusually fast rate is comparable to the rate of binding of 3FN3 to anastellin at saturating anastellin concentrations, consistent with the model in which 3FN3 has to unfold to interact with anastellin. PMID:26517579

  6. The Fibronectin-Binding Protein Fnm Contributes to Adherence to Extracellular Matrix Components and Virulence of Enterococcus faecium

    PubMed Central

    Somarajan, Sudha R.; La Rosa, Sabina Leanti; Singh, Kavindra V.; Roh, Jung H.; Höök, Magnus

    2015-01-01

    The interaction between bacteria and fibronectin is believed to play an important role in the pathogenicity of clinically important Gram-positive cocci. In the present study, we identified a gene encoding a predicted fibronectin-binding protein of Enterococcus faecium (fnm), a homologue of Streptococcus pneumoniae pavA, in the genomes of E. faecium strain TX82 and all other sequenced E. faecium isolates. Full-length recombinant Fnm from strain TX82 bound to immobilized fibronectin in a concentration-dependent manner and also appeared to bind collagen type V and laminin, but not other proteins, such as transferrin, heparin, bovine serum albumin, mucin, or collagen IV. We demonstrated that the N-terminal fragment of Fnm is required for full fibronectin binding, since truncation of this region caused a 2.4-fold decrease (P < 0.05) in the adhesion of E. faecium TX82 to fibronectin. Deletion of fnm resulted in a significant reduction (P < 0.001) in the ability of the mutant, TX6128, to bind fibronectin relative to that of the wild-type strain; in situ reconstitution of fnm in the deletion mutant strain restored adherence. In addition, the Δfnm mutant was highly attenuated relative to TX82 (P ≤ 0.0001) in a mixed-inoculum rat endocarditis model. Taken together, these results demonstrate that Fnm affects the adherence of E. faecium to fibronectin and is important in the pathogenesis of experimental endocarditis. PMID:26371130

  7. Hormonal regulation of focal adhesions in bovine adrenocortical cells: induction of paxillin dephosphorylation by adrenocorticotropic hormone.

    PubMed Central

    Vilgrain, I; Chinn, A; Gaillard, I; Chambaz, E M; Feige, J J

    1998-01-01

    A study of bovine adrenocortical cell shape on adrenocorticotropic hormone (ACTH) challenge showed that the cells round up and develop arborized processes. This effect was found to be (1) specific for ACTH because angiotensin II and basic fibroblast growth factor have no effect; (2) mediated by a cAMP-dependent pathway because forskolin reproduces the effect of the hormone; (3) inhibited by sodium orthovanadate, a phosphotyrosine phosphatase inhibitor, but unchanged by okadaic acid, a serine/threonine phosphatase inhibitor; and (4) correlated with a complete loss of focal adhesions. Biochemical studies of the focal-adhesion-associated proteins showed that pp125fak, vinculin (110 kDa) and paxillin (70 kDa) were detected in the Triton X-100-insoluble fraction from adrenocortical cells. During cell adhesion on fibronectin as substratum, two major phosphotyrosine-containing proteins of molecular masses 125 and 68 kDa were immunodetected in the same fraction. A dramatic decrease in the extent of tyrosine phosphorylation of these proteins was observed within 60 min after treatment with ACTH. No change in pp125fak tyrosine phosphorylation nor in Src activity was detected. In contrast, paxillin was found to be tyrosine-dephosphorylated in a time-dependent manner in ACTH-treated cells. Sodium orthovanadate completely prevented the effect of ACTH. These observations suggest a possible role for phosphotyrosine phosphatases in hormone-dependent cellular regulatory processes. PMID:9601084

  8. Cleavage of extracellular matrix in periodontitis: gingipains differentially affect cell adhesion activities of fibronectin and tenascin-C

    PubMed Central

    Ruggiero, Sabrina; Cosgarea, Raluca; Potempa, Jan; Potempa, Barbara; Eick, Sigrun; Chiquet, Matthias

    2014-01-01

    Gingipains are cysteine proteases that represent major virulence factors of the periodontopathogenic bacterium Porphyromonas gingivalis. Gingipains are reported to degrade extracellular matrix (ECM) of periodontal tissues, leading to tissue destruction and apoptosis. The exact mechanism is not known, however. Fibronectin and tenascin-C are pericellular ECM glycoproteins present in periodontal tissues. Whereas fibronectin mediates fibroblast adhesion, tenascin-C binds to fibronectin and inhibits its cell-spreading activity. Using purified proteins in vitro, we asked whether fibronectin and tenascin-C are cleaved by gingipains at clinically relevant concentrations, and how fragmentation by the bacterial proteases affects their biological activity in cell adhesion. Fibronectin was cleaved into distinct fragments by all three gingipains; however, only arginine-specific HRgpA and RgpB but not lysine-specific Kgp destroyed its cell-spreading activity. This result was confirmed with recombinant cell-binding domain of fibronectin. Of the two major tenascin-C splice variants, the large but not the small was a substrate for gingipains, indicating that cleavage occurred primarily in the alternatively spliced domain. Surprisingly, cleavage of large tenascin-C variant by all three gingipains generated fragments with increased anti-adhesive activity towards intact fibronectin. Fibronectin and tenascin-C fragments were detected in gingival crevicular fluid of a subset of periodontitis patients. We conclude that cleavage by gingipains directly affects the biological activity of both fibronectin and tenascin-C in a manner that might lead to increased cell detachment and loss during periodontal disease. PMID:23313574

  9. Cleavage of extracellular matrix in periodontitis: gingipains differentially affect cell adhesion activities of fibronectin and tenascin-C.

    PubMed

    Ruggiero, Sabrina; Cosgarea, Raluca; Potempa, Jan; Potempa, Barbara; Eick, Sigrun; Chiquet, Matthias

    2013-04-01

    Gingipains are cysteine proteases that represent major virulence factors of the periodontopathogenic bacterium Porphyromonas gingivalis. Gingipains are reported to degrade extracellular matrix (ECM) of periodontal tissues, leading to tissue destruction and apoptosis. The exact mechanism is not known, however. Fibronectin and tenascin-C are pericellular ECM glycoproteins present in periodontal tissues. Whereas fibronectin mediates fibroblast adhesion, tenascin-C binds to fibronectin and inhibits its cell-spreading activity. Using purified proteins in vitro, we asked whether fibronectin and tenascin-C are cleaved by gingipains at clinically relevant concentrations, and how fragmentation by the bacterial proteases affects their biological activity in cell adhesion. Fibronectin was cleaved into distinct fragments by all three gingipains; however, only arginine-specific HRgpA and RgpB but not lysine-specific Kgp destroyed its cell-spreading activity. This result was confirmed with recombinant cell-binding domain of fibronectin. Of the two major tenascin-C splice variants, the large but not the small was a substrate for gingipains, indicating that cleavage occurred primarily in the alternatively spliced domain. Surprisingly, cleavage of large tenascin-C variant by all three gingipains generated fragments with increased anti-adhesive activity towards intact fibronectin. Fibronectin and tenascin-C fragments were detected in gingival crevicular fluid of a subset of periodontitis patients. We conclude that cleavage by gingipains directly affects the biological activity of both fibronectin and tenascin-C in a manner that might lead to increased cell detachment and loss during periodontal disease. PMID:23313574

  10. Production of Fibronectin by the Human Alveolar Macrophage: Mechanism for the Recruitment of Fibroblasts to Sites of Tissue Injury in Interstitial Lung Diseases

    NASA Astrophysics Data System (ADS)

    Rennard, Stephen I.; Hunninghake, Gary W.; Bitterman, Peter B.; Crystal, Ronald G.

    1981-11-01

    Because cells of the mononuclear phagocyte system are known to produce fibronectin and because alveolar macrophages are activated in many interstitial lung diseases, the present study was designed to evaluate a role for the alveolar macrophage as a source of the increased levels of fibronectin found in the lower respiratory tract in interstitial lung diseases and to determine if such fibronectin might contribute to the development of the fibrosis found in these disorders by being a chemoattractant for human lung fibroblasts. Production of fibronectin by human alveolar macrophages obtained by bronchoalveolar lavage and maintained in short-term culture in serum-free conditions was demonstrated; de novo synthesis was confirmed by the incorporation of [14C]proline. This fibronectin had a monomer molecular weight of 220,000 and was antigenically similar to plasma fibronectin. Macrophages from patients with idiopathic pulmonary fibrosis produced fibronectin at a rate 20 times higher than did normal macrophages; macrophages from patients with pulmonary sarcoidosis produced fibronectin at 10 times the normal rate. Macrophages from 6 of 10 patients with various other interstitial disorders produced fibronectin at rates greater than the rate of highest normal control. Human alveolar macrophage fibronectin was chemotactic for human lung fibroblasts, suggesting a functional role for this fibronectin in the derangement of the alveolar structures that is characteristic of these disorders.

  11. Dementia and driving

    MedlinePlus

    ... not drive at times of the day when traffic is heaviest. Do not drive when the weather is bad. Do not drive long distances. Drive only on roads the person is used to. Caregivers should try to lessen ...

  12. A liquid crystalline polymer microlens array with tunable focal intensity by the polarization control of a liquid crystal layer

    NASA Astrophysics Data System (ADS)

    Choi, Yoonseuk; Kim, Hak-Rin; Lee, Kwang-Ho; Lee, Yong-Min; Kim, Jae-Hoon

    2007-11-01

    We propose a focal intensity tunable microlens array by using a birefringent liquid crystalline polymer for lensing action. Due to the difference of effective refractive indices, it acts as a positive or negative microlens with respect to the polarization state. As we control the incident polarization by adding a liquid crystal layer, the focal intensity can be tuned by an applied voltage. Twisted nematic and bistable ferroelectric liquid crystal modes were applied to demonstrate the possibility of various driving features such as a continuously tunable focal intensity or fast switching with memory effect.

  13. GABAergic networks jump-start focal seizures.

    PubMed

    de Curtis, Marco; Avoli, Massimo

    2016-05-01

    Abnormally enhanced glutamatergic excitation is commonly believed to mark the onset of a focal seizure. This notion, however, is not supported by firm evidence, and it will be challenged here. A general reduction of unit firing has been indeed observed in association with low-voltage fast activity at the onset of seizures recorded during presurgical intracranial monitoring in patients with focal, drug-resistant epilepsies. Moreover, focal seizures in animal models start with increased γ-aminobutyric acid (GABA)ergic interneuronal activity that silences principal cells. In vitro studies have shown that synchronous activation of GABAA receptors occurs at seizure onset and causes sizeable elevations in extracellular potassium, thus facilitating neuronal recruitment and seizure progression. A paradoxical involvement of GABAergic networks is required for the initiation of focal seizures characterized by low-voltage fast activity, which represents the most common seizure-onset pattern in focal epilepsies. PMID:27061793

  14. Focal adhesion kinase-dependent focal adhesion recruitment of SH2 domains directs SRC into focal adhesions to regulate cell adhesion and migration

    PubMed Central

    Wu, Jui-Chung; Chen, Yu-Chen; Kuo, Chih-Ting; Wenshin Yu, Helen; Chen, Yin-Quan; Chiou, Arthur; Kuo, Jean-Cheng

    2015-01-01

    Directed cell migration requires dynamical control of the protein complex within focal adhesions (FAs) and this control is regulated by signaling events involving tyrosine phosphorylation. We screened the SH2 domains present in tyrosine-specific kinases and phosphatases found within FAs, including SRC, SHP1 and SHP2, and examined whether these enzymes transiently target FAs via their SH2 domains. We found that the SRC_SH2 domain and the SHP2_N-SH2 domain are associated with FAs, but only the SRC_SH2 domain is able to be regulated by focal adhesion kinase (FAK). The FAK-dependent association of the SRC_SH2 domain is necessary and sufficient for SRC FA targeting. When the targeting of SRC into FAs is inhibited, there is significant suppression of SRC-mediated phosphorylation of paxillin and FAK; this results in an inhibition of FA formation and maturation and a reduction in cell migration. This study reveals an association between FAs and the SRC_SH2 domain as well as between FAs and the SHP2_N-SH2 domains. This supports the hypothesis that the FAK-regulated SRC_SH2 domain plays an important role in directing SRC into FAs and that this SRC-mediated FA signaling drives cell migration. PMID:26681405

  15. Report on SEQUAL/FOCAL

    NASA Astrophysics Data System (ADS)

    Katz, E. J.; Philander, S. G. H.; Richardson, P. L.

    In Eos (April 6, 1982), United States plans for a program to study the dynamic response of the equatorial Atlantic to seasonally varying surface winds were described. Now, 6 years later, we report on progress toward our goal “to describe accurately, and to model correctly” the changes in the currents and density field of the upper equatorial Atlantic Ocean during a 2-year period. A major effort toward this goal was the field phase of SEQUAL (Seasonal Response of the Equatorial Atlantic) and the closely coordinated French program FOCAL (Français Océan et Climat dans l'Atlantique Equatorial).Between February 1983 and September 1984 changes in the surface winds and in oceanic conditions in the equatorial Atlantic were monitored continuously with a variety of instruments. Figure 1 shows key deployments and sections. The resulting data include six current meter moorings, 15 inverted echo sounders and island tide gauges, 57 near-surface drifters, and 18 French and five U.S. cruises that made 1200 hydrographic stations and 800 current profiles. All these data, as well as nearly 10,000 expendable bathythermographs (XBTs) (from the cruises, from air-dropped expendable bathythermograph (AXBT) programs, and from repeated ship of opportunity lines run between 1980 and 1985) were combined and documented by George Heimerdinger, of the National Oceanographic Data Center, and are available from NODC on request.

  16. Focal liver lesions found incidentally

    PubMed Central

    Algarni, Abdullah A; Alshuhri, Abdullah H; Alonazi, Majed M; Mourad, Moustafa Mabrouk; Bramhall, Simon R

    2016-01-01

    Incidentally found focal liver lesions are a common finding and a reason for referral to hepatobiliary service. They are often discovered in patients with history of liver cirrhosis, colorectal cancer, incidentally during work up for abdominal pain or in a trauma setting. Specific points should considered during history taking such as risk factors of liver cirrhosis; hepatitis, alcohol consumption, substance exposure or use of oral contraceptive pills and metabolic syndromes. Full blood count, liver function test and tumor markers can act as a guide to minimize the differential diagnosis and to categorize the degree of liver disease. Imaging should start with B-mode ultrasound. If available, contrast enhanced ultrasound is a feasible, safe, cost effective option and increases the ability to reach a diagnosis. Contrast enhanced computed tomography should be considered next. It is more accurate in diagnosis and better to study anatomy for possible operation. Contrast enhanced magnetic resonance is the gold standard with the highest sensitivity. If doubt still remains, the options are biopsy or surgical excision. PMID:27028805

  17. Early vision and focal attention

    NASA Astrophysics Data System (ADS)

    Julesz, Bela

    1991-07-01

    At the thirty-year anniversary of the introduction of the technique of computer-generated random-dot stereograms and random-dot cinematograms into psychology, the impact of the technique on brain research and on the study of artificial intelligence is reviewed. The main finding-that stereoscopic depth perception (stereopsis), motion perception, and preattentive texture discrimination are basically bottom-up processes, which occur without the help of the top-down processes of cognition and semantic memory-greatly simplifies the study of these processes of early vision and permits the linking of human perception with monkey neurophysiology. Particularly interesting are the unexpected findings that stereopsis (assumed to be local) is a global process, while texture discrimination (assumed to be a global process, governed by statistics) is local, based on some conspicuous local features (textons). It is shown that the top-down process of "shape (depth) from shading" does not affect stereopsis, and some of the models of machine vision are evaluated. The asymmetry effect of human texture discrimination is discussed, together with recent nonlinear spatial filter models and a novel extension of the texton theory that can cope with the asymmetry problem. This didactic review attempts to introduce the physicist to the field of psychobiology and its problems-including metascientific problems of brain research, problems of scientific creativity, the state of artificial intelligence research (including connectionist neural networks) aimed at modeling brain activity, and the fundamental role of focal attention in mental events.

  18. [The influence of immobilized fibronectin on karyotypic variability of two rat kangaroo kidney cell lines].

    PubMed

    Polianskaia, G G; Goriachaia, T S; Pinaev, G P

    2007-01-01

    The numerical and structural karyotypic variability has been investigated in "markerless" Rat kangaroo kidney cell lines NBL-3-17 and NBL-3-11 when cultivating on a fibronectin-coated surface. In cell line NBL-3-17, cultivated on the fibronectin-coated surface for 1, 2, 4 and 8 days, the character of cell distribution for the chromosome number has changed. These changes involve a significant decrease in frequency of cells with modal number of chromosomes, and an increase in frequency of cells with lower chromosomal number. Many new additional structural variants of the karyotype (SVK) appear. The observed alterations seem to be due preference adhesion of cells with lower chromosome number, disturbances of mitotic apparatus and selection of SVK, which are more adopted to changes in culture conditions. Detachment of cells from the fibronectin-coated surface, followed by 5 days cultivation on a hydrophilic surface restored control distribution. In cell line NBL-3-11, cultivated on the fibronectin-coated surface for 1, 2, 4 and 8 days, the character of numerical karyotypic variability did not change compared to control variants. In cell line NBL-3-17 the frequency of chromosomal aberrations under cultivation on the fibronectin-coated surface for 1, 2, 4 and 8 days did not change relative to control variants. In cell line NBL-3-11 the frequency of chromosomal aberrations under the same conditions significantly increases, mainly at the expence of chromosomal, chromatid breaks and dicentrics (telomeric association) relative to control variants. We discuss possible reasons of differences in the character of numerical and structural karyotypic variability between cell lines NBL-3-17 (hypotriploid) and NBL-3-11 (hypodiploid) under cultivation on fibronectin. The reasons of the observed interline karyotypic differences possibly consist in peculiarity of karyotypic structure of cell line NBL-3-11 and in the change of gene expression, namely in a dose of certain functioning

  19. Surface oxide net charge of a titanium alloy: modulation of fibronectin-activated attachment and spreading of osteogenic cells.

    PubMed

    Rapuano, Bruce E; MacDonald, Daniel E

    2011-01-01

    In the current study, we have altered the surface oxide properties of a Ti6Al4V alloy using heat treatment or radiofrequency glow discharge (RFGD) in order to evaluate the relationship between the physico-chemical and biological properties of the alloy's surface oxide. The effects of surface pretreatments on the attachment of cells from two osteogenic cell lines (MG63 and MC3T3) and a mesenchymal stem cell line (C3H10T1/2) to fibronectin adsorbed to the alloy were measured. Both heat and RFGD pretreatments produced a several-fold increase in the number of cells that attached to fibronectin adsorbed to the alloy at a range of coating concentrations (0.001-10nM FN) for each cell line tested. An antibody (HFN7.1) directed against the central integrin binding domain of fibronectin produced a 65-70% inhibition of cell attachment to fibronectin-coated disks, indicating that cell attachment to the metal discs was dependent on fibronectin binding to cell integrin receptors. Both treatments also accelerated the cell spreading response manifested by extensive flattening and an increase in mean cellular area. The treatment-induced increases in the cell attachment activity of adsorbed fibronectin were correlated with previously demonstrated increases in Ti6Al4V oxide negative net surface charge at physiological pH produced by both heat and RFGD pretreatments. Since neither treatment increased the adsorption mass of fibronectin, these findings suggest that negatively charged surface oxide functional groups in Ti6Al4V can modulate fibronectin's integrin receptor activity by altering the adsorbed protein's conformation. Our results further suggest that negatively charged functional groups in the surface oxide can play a prominent role in the osseointegration of metallic implant materials. PMID:20884181

  20. Fibronectin-binding protein of Streptococcus pyogenes: sequence of the binding domain involved in adherence of streptococci to epithelial cells.

    PubMed Central

    Talay, S R; Valentin-Weigand, P; Jerlström, P G; Timmis, K N; Chhatwal, G S

    1992-01-01

    The sequence of the fibronectin-binding domain of the fibronectin-binding protein of Streptococcus pyogenes (Sfb protein) was determined, and its role in streptococcal adherence was investigated by use of an Sfb fusion protein in adherence studies. A 1-kb DNA fragment coding for the binding domain of Sfb protein was cloned into the expression vector pEX31 to produce an Sfb fusion protein consisting of the N-terminal part of MS2 polymerase and a C-terminal fragment of the streptococcal protein. Induction of the vector promoter resulted in hyperexpression of fibronectin-binding fusion protein in the cytoplasm of the recombinant Escherichia coli cells. Sequence determination of the cloned 1-kb fragment revealed an in-frame reading frame for a 268-amino-acid peptide composed of a 37-amino-acid sequence which is completely repeated three times and incompletely repeated a fourth time. Cloning of one repeat into pEX31 resulted in expression of small fusion peptides that show fibronectin-binding activity, indicating that one repeat contains at least one binding domain. Each repeat exhibits two charged domains and shows high homology with the 38-amino-acid D3 repeat of the fibronectin-binding protein of Staphylococcus aureus. Sequence comparison with other streptococcal ligand-binding surface proteins, including M protein, failed to reveal significant homology, which suggests that Sfb protein represents a novel type of functional protein in S. pyogenes. The Sfb fusion protein isolated from the cytoplasm of recombinant cells was purified by fast protein liquid chromatography. It showed a strong competitive inhibition of fibronectin binding to S. pyogenes and of the adherence of bacteria to cultured epithelial cells. In contrast, purified streptococcal lipoteichoic acid showed only a weak inhibition of fibronectin binding and streptococcal adherence. These results demonstrate that Sfb protein is directly involved in the fibronectin-mediated adherence of S. pyogenes to

  1. Simple application of fibronectin-mimetic coating enhances osseointegration of titanium implants

    PubMed Central

    Petrie, Timothy A.; Reyes, Catherine D.; Burns, Kellie L.; García, Andrés J.

    2009-01-01

    Integrin-mediated cell adhesion to biomolecules adsorbed onto biomedical devices regulates device integration and performance. Because of the central role of integrin-fibronectin (FN) interactions in osteoblastic function and bone formation, we evaluated the ability of fibronectin-inspired biomolecular coatings to promote osteoblastic differentiation and implant osseointegration. Notably, these biomolecular coatings relied on physical adsorption of FN-based ligands onto biomedical-grade titanium as a simple, clinically-translatable strategy to functionalize medical implants. Surfaces coated with a recombinant fragment of FN spanning the central cell binding domain enhanced osteoblastic differentiation and mineralization in bone marrow stromal cell cultures and increased implant osseointegration in a rat cortical bone model compared to passively adsorbed RGD peptides, serum proteins, and full-length FN. Differences in biological responses correlated with integrin binding specificity and signaling among surface coatings. This work validates a simple, clinically-translatable, surface biofunctionalization strategy to enhance biomedical device integration. PMID:18752639

  2. EDA-containing fibronectin levels in the cerebrospinal fluid of children with meningitis.

    PubMed

    Pupek, Małgorzata; Jasonek, Jolanta; Kątnik-Prastowska, Iwona

    2013-01-01

    Fibronectin containing an alternatively spliced extra domain A (EDA-FN) participates in diverse biological cell functions, being also directly or indirectly engaged during an inflammatory response to brain injury and/or neuron regeneration. We analyzed FN and EDA-FN isoform levels by ELISA in 85 cerebrospinal fluid samples and 67 plasma samples obtained from children suffering from bacterial or viral meningitis and non-meningitis peripheral inflammation. We have found that the cerebrospinal level of EDA-FN was significantly lower in the bacterial meningitis group than in the viral- and non-meningitis groups. In the patients' plasma, EDA-FN was almost undetectable. The determination of fibronectin containing the EDA segment might be considered as an additional diagnostic marker of bacterial meningitis in children. PMID:23884219

  3. Identification of Surface Proteins from Lactobacillus casei BL23 Able to Bind Fibronectin and Collagen.

    PubMed

    Muñoz-Provencio, Diego; Pérez-Martínez, Gaspar; Monedero, Vicente

    2011-03-01

    Strains of lactobacilli show the capacity to attach to extracellular matrix proteins. Cell-wall fractions of Lactobacillus casei BL23 enriched in fibronectin, and collagen-binding proteins were isolated. Mass spectrometry analysis of their protein content revealed the presence of stress-related proteins (GroEL, ClpL), translational elongation factors (EF-Tu, EF-G), oligopeptide solute-binding proteins, and the glycolytic enzymes enolase and glyceraldehyde-3-phosphate dehydrogenase (GAPDH). The latter two enzymes were expressed in Escherichia coli and purified as glutathione-S-transferase (GST) fusion proteins, and their in vitro binding activity to fibronectin and collagen was confirmed. These results reinforce the idea that lactobacilli display on their surfaces a variety of moonlighting proteins that can be important in their adaptation to survive at intestinal mucosal sites and in the interaction with host cells. PMID:26781495

  4. Unilateral Isolated Proximal Femoral Focal Deficiency

    PubMed Central

    Doğer, Emek; Köpük, Şule Y.; Çakıroğlu, Yiğit; Çakır, Özgür; Yücesoy, Gülseren

    2013-01-01

    Objective. To discuss a patient with a prenatal diagnosis of unilateral isolated femoral focal deficiency. Case. Antenatal diagnosis of unilateral isolated femoral focal deficiency was made at 20 weeks of gestation. The length of left femur was shorter than the right, and fetal femur length was below the fifth percentile. Proximal femoral focal deficiency was diagnosed. After delivery, the diagnosis was confirmed with skeletal radiographs and magnetic resonance imaging. In prenatal ultrasonographic examination, the early recognition and exclusion of skeletal dysplasias is important; moreover, treatment plans should be initiated, and valuable information should be provided to the family. PMID:23984135

  5. Oxidative damage to fibronectin. 2. The effect of H2O2 and the hydroxyl radical

    SciTech Connect

    Vissers, M.C.; Winterbourn, C.C. )

    1991-03-01

    The effect of H2O2 and the hydroxyl radical (.OH) on fibronectin was investigated. .OH was generated in three ways: (1) by radiolysis with 60Co under N2O, or by the Fenton system using either (2) equimolar Fe(2+)-EDTA and H2O2 or (3) H2O2 and catalytic amounts of Fe(2+)-EDTA recycled with ascorbate. Each system had a different effect. H2O2 alone caused no changes, even at an 800-fold molar excess. Radiolytic .OH caused a rapid loss of tryptophan fluorescence, an increase in bityrosine fluorescence, and extensive crosslinking. The Fenton system using Fe-EDTA, H2O2, and ascorbate caused a loss in tryptophan fluorescence, a smaller increase in bityrosine than was seen with radiolytic .OH, and a threefold increase in carbonyl groups. On sodium dodecyl sulfate-polyacrylamide gel electrophoresis fragmentation of fibronectin was seen. In contrast, when .OH was generated with equimolar Fe-EDTA and H2O2, the only change was a small increase in bityrosine fluorescence at the highest dose of oxidant. None of the systems used affected cysteine. All the changes except the loss of tryptophan by radiolytic .OH were completely inhibited with mannitol. The differences seen with radiolytic .OH and the Fe-EDTA, H2O2, ascorbate system were not solely due to O2 in the latter system since similar results were obtained under N2. The differences between radiolytic .OH and the Fenton systems could be partly due to the components of the latter systems reacting with .OH and thus competing with fibronectin. The authors results demonstrate that the extent and type of fibronectin damage by .OH is dependent on the mode of radical generation.

  6. Fibronectin and vitronectin promote human fetal osteoblast cell attachment and proliferation on nanoporous titanium surfaces

    PubMed Central

    Rivera-Chacon, D. M.; Alvarado-Velez, M.; Acevedo-Morantes, C.Y.; Singh, S.P.; Gultepe, E.; Nagesha, D.; Sridhar, S.; Ramirez-Vick, J.E.

    2013-01-01

    Improvements in osteoconduction of implant biomaterials require focusing on the bone-implant interface, which is a complex multifactorial system. Surface topography of implants plays a crucial role at this interface. Nanostructured surfaces have been shown to promote serum protein adsorption and osteoblast adhesion when compared to microstructured surfaces for bone-implant materials. We studied the influence of the serum proteins fibronectin and vitronectin on the attachment and proliferation of osteoblasts onto nanostructured titania surfaces. Human fetal osteoblastic cells hFOB 1.19 were used as model osteoblasts and were grown on nanoporous TiO2 templates, using Ti6Al4V and commercially pure Ti substrates as controls. Results show a significant increase in cell proliferation on nanoporous TiO2 over flat substrates. Initial cell attachment data exhibited a significant effect by either fibronectin or vitronectin on cell adhesion at the surface of any of the tested materials. In addition, the extent of cell adhesion was significantly different between the nanoporous TiO2 and both Ti6Al4V and commercially pure Ti substrates, with the first showing the highest surface coverage. There was no significant difference on osteoblast attachment or proliferation between the presence of fibronectin or vitronectin using any of the material substrates. Taken together, these results suggest that the increase in osteoblast attachment and proliferation shown on the nanoporous TiO2 is due to an increase in the adsorption of fibronectin and vitronectin because of the higher surface area and to an enhanced protein unfolding, which allows access to osteoblast binding motifs within these proteins. PMID:23858975

  7. Identification of a fibronectin interaction site in the extracellular matrix protein ameloblastin.

    PubMed

    Beyeler, Michael; Schild, Christof; Lutz, Roman; Chiquet, Matthias; Trueb, Beat

    2010-04-15

    Mammalian teeth are composed of hydroxyapatite crystals that are embedded in a rich extracellular matrix. This matrix is produced by only two cell types, the mesenchymal odontoblasts and the ectodermal ameloblasts. Ameloblasts secrete the enamel proteins amelogenin, ameloblastin, enamelin and amelotin. Odontoblasts secrete collagen type I and several calcium-binding phosphoproteins including dentin sialophosphoprotein, dentin matrix protein, bone sialoprotein and osteopontin. The latter four proteins have recently been grouped in the family of the SIBLINGs (small integrin-binding ligand, N-linked glycoproteins) because they display similar gene structures and because they contain an RGD tripeptide sequence that binds to integrin receptors and thus mediates cell adhesion. We have prepared all the other tooth-specific proteins in recombinant form and examined whether they might also promote cell adhesion similar to the SIBLINGs. We found that only ameloblastin consistently mediated adhesion of osteoblastic and fibroblastic cells to plastic or titanium surfaces. The activity was dependent on the intact three-dimensional structure of ameloblastin and required de novo protein synthesis of the adhering cells. By deletion analysis and in vitro mutagenesis, the active site could be narrowed down to a sequence of 13 amino acid residues (VPIMDFADPQFPT) derived from exon 7 of the rat ameloblastin gene or exons 7-9 of the human gene. Kinetic studies and RNA interference experiments further demonstrated that this sequence does not directly bind to a cell surface receptor but that it interacts with cellular fibronectin, which in turn binds to integrin receptors. The identification of a fibronectin-binding domain in ameloblastin might permit interesting applications for dental implantology. Implants could be coated with peptides containing the active sequence, which in turn would recruit fibronectin from the patient's blood. The recruited fibronectin should then promote cell

  8. Fibronectin induction abrogates the BRAF inhibitor response of BRAF V600E/PTEN-null melanoma cells

    PubMed Central

    Fedorenko, Inna V.; Abel, Ethan V.; Koomen, John M.; Fang, Bin; Wood, Elizabeth R.; Chen, Y. Ann; Fisher, Kate J.; Iyengar, Sanjana; Dahlman, Kimberly B.; Wargo, Jennifer A.; Flaherty, Keith T.; Sosman, Jeffrey A.; Sondak, Vernon K.; Messina, Jane L.; Gibney, Geoffrey T.; Smalley, Keiran S.M.

    2015-01-01

    The mechanisms by which some melanoma cells adapt to BRAF inhibitor therapy are incompletely understood. In the present study, we used mass spectrometry-based phosphoproteomics to determine how BRAF inhibition remodeled the signaling network of melanoma cell lines that were BRAF-mutant and PTEN-null. Short-term BRAF inhibition was associated with marked changes in fibronectin-based adhesion signaling that were PTEN-dependent. These effects were recapitulated through BRAF siRNA knockdown and following treatment with chemotherapeutic drugs. Increased fibronectin expression was also observed in mouse xenograft models as well as specimens from melanoma patients undergoing BRAF inhibitor treatment. Analysis of a melanoma TMA showed loss of PTEN expression to predict for a lower overall survival, with a trend for even lower survival being seen when loss of fibronectin was included in the analysis. Mechanistically, the induction of fibronectin limited the responses of these PTEN-null melanoma cell lines to vemurafenib, with enhanced cytotoxicity observed following the knockdown of either fibronectin or its receptor α5β1 integrin. This in turn abrogated the cytotoxic response to BRAF inhibition via increased AKT signaling, which prevented the induction of cell death by maintaining the expression of the pro-survival protein Mcl-1. The protection conveyed by the induction of fibronectin expression could be overcome through combined treatment with a BRAF and PI3K inhibitor. PMID:26073081

  9. Characterization of a novel family of fibronectin-binding proteins with M23 peptidase domains from Treponema denticola

    PubMed Central

    Bamford, C.V.; Francescutti, T.; Cameron, C.E.; Jenkinson, H.F.; Dymock, D.

    2011-01-01

    SUMMARY Interactions with fibronectin are important in the virulence strategies of a range of disease-related bacteria. The periodontitis-associated oral spirochaete Treponema denticola expresses at least two fibronectin-binding proteins, designated Msp (major surface protein) and OppA (oligopeptide-binding protein homologue). To identify other T. denticola outer membrane fibronectin-binding proteins, the amino acid sequence of the Treponema pallidum fibronectin-binding protein Tp0155 was used to survey the T. denticola genome. Seven T. denticola genes encoding orthologous proteins were identified. All but two were expressed in Escherichia coli and purified recombinant proteins bound fibronectin. Using antibodies to the N-terminal region of Tp0155, it was demonstrated that T. denticola TDE2318, with highest homology to Tp0155, was cell surface localized. Like Tp0155, the seven T. denticola proteins contained an M23 peptidase domain and four (TDE2318, TDE2753, TDE1738, TDE1297) contained one or two LysM domains. M23 peptidases can degrade peptidoglycan whereas LysM domains recognize carbohydrate polymers. In addition, TDE1738 may act as a bacteriocin based on homology with other bacterial lysins and the presence of an adjacent gene encoding a putative immunity factor. Collectively, these results suggest that T. denticola expresses fibronectin-binding proteins associated with the cell surface that may also have cell wall modifying or lytic functions. PMID:21040511

  10. Identification and isolation of a 140 kd cell surface glycoprotein with properties expected of a fibronectin receptor

    SciTech Connect

    Pytela, R.; Pierschbacher, M.D.; Ruoslahti, E.

    1985-01-01

    Affinity chromatography was used to identify a putative cell surface receptor for fibronectin. A large cell-attachment-promoting fibronectin fragment was used as the affinity matrix, and specific elution was effected by using synthetic peptides containing the sequence Arg-Gly-Asp, which is derived from the cell recognition sequence in the fibronectin cell attachment site. A 140 kd protein was bound by the affinity matrix from octylglucoside extracts of MG-63 human osteosarcoma cells and specifically eluted with the synthetic peptide Gly-Arg-Gly-Asp-Ser-Pro. The 140 kd protein was labeled by cell surface specific radioiodination and became incorporated into liposomes at a high efficiency. Liposomes containing this protein showed specific affinity toward fibronectin-coated surfaces, and this binding could be selectively inhibited by the synthetic cell-attachment peptide but not by inactive peptides. Affinity chromatography on wheat germ agglutinin-Sepharose showed that the 140 kd protein is a glycoprotein and, in combination with the fibronectin fragment chromatography, gave highly enriched preparations of the 140 kd protein. These properties suggest that the 140 kd glycoprotein is a membrane-embedded cell surface protein directly involved in the initial step of cell adhesion to fibronectin substrates.

  11. Fibronectin-Alginate microcapsules improve cell viability and protein secretion of encapsulated Factor IX-engineered human mesenchymal stromal cells.

    PubMed

    Sayyar, Bahareh; Dodd, Megan; Marquez-Curtis, Leah; Janowska-Wieczorek, Anna; Hortelano, Gonzalo

    2015-01-01

    Continuous delivery of proteins by engineered cells encapsu-lated in biocompatible polymeric microcapsules is of considerable therapeutic potential. However, this technology has not lived up to expectations due to inadequate cell--matrix interactions and subsequent cell death. In this study we hypoth-esize that the presence of fibronectin in an alginate matrix may enhance the viability and functionality of encapsulated human cord blood-derived mesenchymal stromal cells (MSCs) expressing the human Factor IX (FIX) gene. MSCs were encapsulated in alginate-PLL microcapsules containing 10, 100, or 500 μg/ml fibronectin to ameliorate cell survival. MSCs in microcapsules with 100 and 500 μg/ml fibronectin demonstrated improved cell viability and proliferation and higher FIX secretion compared to MSCs in non-supplemented microcapsules. In contrast, 10 μg/ml fibronectin did not significantly affect the viability and protein secretion from the encapsulated cells. Differentiation studies demonstrated osteogenic (but not chondrogenic or adipogenic) differentiation capability and efficient FIX secretion of the enclosed MSCs in the fibronectin-alginate suspension culture. Thus, the use of recombinant MSCs encapsulated in fibronectin-alginate microcapsules in basal or osteogenic cultures may be of practical use in the treatment of hemophilia B. PMID:24564349

  12. Topical tretinoin increases the tropoelastin and fibronectin content of photoaged hairless mouse skin.

    PubMed

    Schwartz, E; Kligman, L H

    1995-04-01

    Topical tretinoin treatment of photoaged hairless mice has been shown in previous studies to stimulate formation of a subepidermal zone of new connective tissue characterized by enhanced collagen synthesis. The aims of this study were to localize and/or quantify elastin, fibronectin, and glycosaminoglycans in the same model. Hairless mice (Skh-1) were irradiated thrice weekly for 10 weeks with gradually increasing doses of ultraviolet (up to 4.5 minimal erythema doses per exposure) from Westinghouse FS-40 bulbs. Mice were then treated five times a week with either 0.05% tretinoin, the ethanol:propylene glycol vehicle, or nothing for another 10 weeks. Controls included mice sacrificed after 10 weeks of ultraviolet treatment and age-matched untreated animals. The distribution of elastin and fibronectin was examined by immunofluorescence microscopy, which revealed fine fibrils in the subepidermal zone in tretinoin-treated skin. A quantitative slot-blot immunobinding assay showed that tretinoin induced a threefold higher amount of tropoelastin compared with controls. Insoluble elastin content (desmosine levels) was similar in all groups. Although fibronectin content was increased by ultraviolet radiation, tretinoin treatment induced the largest increase. In contrast, the amount of glycosaminoglycans, although increased by UVB radiation, was reduced by tretinoin treatment. PMID:7706770

  13. Collagen fibrillogenesis: fibronectin, integrins, and minor collagens as organizers and nucleators

    PubMed Central

    Kadler, Karl E; Hill, Adele; Canty-Laird, Elizabeth G

    2008-01-01

    Collagens are triple helical proteins that occur in the extracellular matrix (ECM) and at the cell–ECM interface. There are more than 30 collagens and collagen-related proteins but the most abundant are collagens I and II that exist as D-periodic (where D = 67 nm) fibrils. The fibrils are of broad biomedical importance and have central roles in embryogenesis, arthritis, tissue repair, fibrosis, tumor invasion, and cardiovascular disease. Collagens I and II spontaneously form fibrils in vitro, which shows that collagen fibrillogenesis is a selfassembly process. However, the situation in vivo is not that simple; collagen I-containing fibrils do not form in the absence of fibronectin, fibronectin-binding and collagen-binding integrins, and collagen V. Likewise, the thin collagen II-containing fibrils in cartilage do not form in the absence of collagen XI. Thus, in vivo, cellular mechanisms are in place to control what is otherwise a protein self-assembly process. This review puts forward a working hypothesis for how fibronectin and integrins (the organizers) determine the site of fibril assembly, and collagens V and XI (the nucleators) initiate collagen fibrillogenesis. PMID:18640274

  14. Periodontal healing following guided tissue regeneration with citric acid and fibronectin application.

    PubMed

    Caffesse, R G; Nasjleti, C E; Anderson, G B; Lopatin, D E; Smith, B A; Morrison, E C

    1991-01-01

    This study was undertaken to determine the effects of guided tissue regeneration (GTR) with and without citric acid conditioning and autologous fibronectin application. The study subjects were four female beagle dogs with spontaneous periodontitis. The dogs were given thorough root debridement and 4 weeks later, mucoperiosteal flaps were raised on both sides of the mandible involving the 2nd, 3rd, and 4th premolar and 1st molar teeth. After debridement, notches were placed on the roots at the level of supporting bone. Citric acid (pH 1) was topically applied for 3 minutes on the exposed root surfaces of one side (experimental). The roots were irrigated with normal saline solution. Both the root surfaces and the inner surface of the flap were then bathed in autologous fibronectin in saline. Following this, Gore-Tex periodontal material was adapted to the roots of each tooth and sutured. The contralateral side, serving as control, was treated by surgery and application of Gore-Tex periodontal material only. All membranes were removed 1 month after surgery, and the dogs sacrificed at 3 months. Both mesio-distal and bucco-lingual microscopic histological sections were evaluated by descriptive histology, and linear measurements and surface area determination of the furcal tissues were made. Periodontal healing following the use of GTR procedure resulted in an increase in connective tissue and alveolar bone regeneration. Adjunctive critic acid plus autologous fibronectin produced slightly better results, but these differences were not statistically significant for this sample. PMID:2002428

  15. Functional Analysis of an S-Layer-Associated Fibronectin-Binding Protein in Lactobacillus acidophilus NCFM.

    PubMed

    Hymes, Jeffrey P; Johnson, Brant R; Barrangou, Rodolphe; Klaenhammer, Todd R

    2016-05-01

    Bacterial surface layers (S-layers) are crystalline arrays of self-assembling proteinaceous subunits called S-layer proteins (Slps) that comprise the outermost layer of the cell envelope. Many additional proteins that are associated with or embedded within the S-layer have been identified inLactobacillus acidophilusNCFM, an S-layer-forming bacterium that is widely used in fermented dairy products and probiotic supplements. One putative S-layer-associated protein (SLAP), LBA0191, was predicted to mediate adhesion to fibronectin based on thein silicodetection of a fibronectin-binding domain. Fibronectin is a major component of the extracellular matrix (ECM) of intestinal epithelial cells. Adhesion to intestinal epithelial cells is considered an important trait for probiotic microorganisms during transit and potential association with the intestinal mucosa. To investigate the functional role of LBA0191 (designated FbpB) inL. acidophilusNCFM, anfbpB-deficient strain was constructed. TheL. acidophilusmutant with a deletion offbpBlost the ability to adhere to mucin and fibronectinin vitro Homologues offbpBwere identified in five additional putative S-layer-forming species, but no homologues were detected in species outside theL. acidophilushomology group. PMID:26921419

  16. Tuning Mesenchymal Stem Cell Response onto Titanium-Niobium-Hafnium Alloy by Recombinant Fibronectin Fragments.

    PubMed

    Herranz-Diez, C; Mas-Moruno, C; Neubauer, S; Kessler, H; Gil, F J; Pegueroles, M; Manero, J M; Guillem-Marti, J

    2016-02-01

    Since metallic biomaterials used for bone replacement possess low bioactivity, the use of cell adhesive moieties is a common strategy to improve cellular response onto these surfaces. In recent years, the use of recombinant proteins has emerged as an alternative to native proteins and short peptides owing to the fact that they retain the biological potency of native proteins, while improving their stability. In the present study, we investigated the biological effect of two different recombinant fragments of fibronectin, spanning the 8-10th and 12-14th type III repeats, covalently attached to a new TiNbHf alloy using APTES silanization. The fragments were studied separately and mixed at different concentrations and compared to a linear RGD, a cyclic RGD and the full-length fibronectin protein. Cell culture studies using rat mesenchymal stem cells demonstrated that low to medium concentrations (30% and 50%) of type III 8-10th fragment mixed with type III 12-14th fragment stimulated cell spreading and proliferation compared to RGD peptides and the fragments separately. On the other hand, type III 12-14th fragment alone or mixed at low volume percentages ≤50% with type III 8-10th fragment increased alkaline phosphatase levels compared to the other molecules. These results are significant for the understanding of the role of fibronectin recombinant fragments in cell responses and thus to design bioactive coatings for biomedical applications. PMID:26735900

  17. Osteoblast mineralization requires β1 integrin/ICAP-1–dependent fibronectin deposition

    PubMed Central

    Brunner, Molly; Millon-Frémillon, Angélique; Chevalier, Genevieve; Nakchbandi, Inaam A.; Mosher, Deane; Block, Marc R.

    2011-01-01

    The morphogenetic and differentiation events required for bone formation are orchestrated by diffusible and insoluble factors that are localized within the extracellular matrix. In mice, the deletion of ICAP-1, a modulator of β1 integrin activation, leads to severe defects in osteoblast proliferation, differentiation, and mineralization and to a delay in bone formation. Deposition of fibronectin and maturation of fibrillar adhesions, adhesive structures that accompany fibronectin deposition, are impaired upon ICAP-1 loss, as are type I collagen deposition and mineralization. Expression of β1 integrin with a mutated binding site for ICAP-1 recapitulates the ICAP-1–null phenotype. Follow-up experiments demonstrated that ICAP-1 negatively regulates kindlin-2 recruitment onto the β1 integrin cytoplasmic domain, whereas an excess of kindlin-2 binding has a deleterious effect on fibrillar adhesion formation. These results suggest that ICAP-1 works in concert with kindlin-2 to control the dynamics of β1 integrin–containing fibrillar adhesions and, thereby, regulates fibronectin deposition and osteoblast mineralization. PMID:21768292

  18. Osteoblast mineralization requires beta1 integrin/ICAP-1-dependent fibronectin deposition.

    PubMed

    Brunner, Molly; Millon-Frémillon, Angélique; Chevalier, Genevieve; Nakchbandi, Inaam A; Mosher, Deane; Block, Marc R; Albigès-Rizo, Corinne; Bouvard, Daniel

    2011-07-25

    The morphogenetic and differentiation events required for bone formation are orchestrated by diffusible and insoluble factors that are localized within the extracellular matrix. In mice, the deletion of ICAP-1, a modulator of β1 integrin activation, leads to severe defects in osteoblast proliferation, differentiation, and mineralization and to a delay in bone formation. Deposition of fibronectin and maturation of fibrillar adhesions, adhesive structures that accompany fibronectin deposition, are impaired upon ICAP-1 loss, as are type I collagen deposition and mineralization. Expression of β1 integrin with a mutated binding site for ICAP-1 recapitulates the ICAP-1-null phenotype. Follow-up experiments demonstrated that ICAP-1 negatively regulates kindlin-2 recruitment onto the β1 integrin cytoplasmic domain, whereas an excess of kindlin-2 binding has a deleterious effect on fibrillar adhesion formation. These results suggest that ICAP-1 works in concert with kindlin-2 to control the dynamics of β1 integrin-containing fibrillar adhesions and, thereby, regulates fibronectin deposition and osteoblast mineralization. PMID:21768292

  19. Assay to mechanically tune and optically probe fibrillar fibronectin conformations from fully relaxed to breakage.

    PubMed

    Little, William C; Smith, Michael L; Ebneter, Urs; Vogel, Viola

    2008-06-01

    In response to growing needs for quantitative biochemical and cellular assays that address whether the extracellular matrix (ECM) acts as a mechanochemical signal converter to co-regulate cellular mechanotransduction processes, a new assay is presented where plasma fibronectin fibers are manually deposited onto elastic sheets, while force-induced changes in protein conformation are monitored by fluorescence resonance energy transfer (FRET). Fully relaxed assay fibers can be stretched at least 5-6 fold, which involves Fn domain unfolding, before the fibers break. In native fibroblast ECM, this full range of stretch-regulated conformations coexists in every field of view confirming that the assay fibers are physiologically relevant model systems. Since alterations of protein function will directly correlate with their extension in response to force, the FRET vs. strain curves presented herein enable the mapping of fibronectin strain distributions in 2D and 3D cell cultures with high spatial resolution. Finally, cryptic sites for fibronectin's N-terminal 70-kD fragment were found to be exposed at relatively low strain, demonstrating the assay's potential to analyze stretch-regulated protein-protein interactions. PMID:18417335

  20. Fibronectin-Tissue Transglutaminase Matrix Rescues RGD-impaired Cell Adhesion through Syndecan-4 and β1 Integrin Co-signaling*S⃞

    PubMed Central

    Telci, Dilek; Wang, Zhuo; Li, Xiaoling; Verderio, Elisabetta A. M.; Humphries, Martin J.; Baccarini, Manuela; Basaga, Huveyda; Griffin, Martin

    2008-01-01

    Heterotropic association of tissue transglutaminase (TG2) with extracellular matrix-associated fibronectin (FN) can restore the adhesion of fibroblasts when the integrin-mediated direct binding to FN is impaired using RGD-containing peptide. We demonstrate that the compensatory effect of the TG-FN complex in the presence of RGD-containing peptides is mediated by TG2 binding to the heparan sulfate chains of the syndecan-4 cell surface receptor. This binding mediates activation of protein kinase Cα (PKCα) and its subsequent interaction with β1 integrin since disruption of PKCα binding to β1 integrins with a cell-permeant competitive peptide inhibits cell adhesion and the associated actin stress fiber formation. Cell signaling by this process leads to the activation of focal adhesion kinase and ERK1/2 mitogen-activated protein kinases. Fibroblasts deficient in Raf-1 do not respond fully to the TG-FN complex unless either the full-length kinase competent Raf-1 or the kinase-inactive domain of Raf-1 is reintroduced, indicating the involvement of the Raf-1 protein in the signaling mechanism. We propose a model for a novel RGD-independent cell adhesion process that could be important during tissue injury and/or remodeling whereby TG-FN binding to syndecan-4 activates PKCα leading to its association with β1 integrin, reinforcement of actin-stress fiber organization, and MAPK pathway activation. PMID:18499669

  1. Biosynthesis, surface expression and function of the fibronectin receptor after rat liver cell transformation to tumorigenicity.

    PubMed Central

    Decastel, M; Doyennette-Moyne, M A; Gouet, E; Aubery, M; Codogno, P

    1993-01-01

    Zajdela hepatoma cells are poorly-adherent cells derived from an undifferentiated tumour and transplanted into rat. We compared the biosynthesis, structure and function of the fibronectin receptor in normal rat hepatocytes with that in Zajdela hepatoma cells. The rat hepatocyte fibronectin receptor has been isolated. It is composed of two subunits: alpha 5 (molecular mass 155 kDa) and beta 1 (molecular mass 115 kDa). However, its biosynthesis has not yet been described. Using polyclonal antibodies raised against each of the subunits of the receptor, we observed that the alpha 5-subunit was synthesized as a 155-kDa polypeptide in normal rat hepatocytes and Zajdela hepatoma cells. In contrast, the molecular mass of the beta 1-subunit was 130 kDa in Zajdela hepatoma cells versus 115 kDa in normal rat hepatocytes. Pulse-chase experiments showed that the apparent transition time from the 100-kDa beta 1-precursor to the 130-kDa mature form was abnormally prolonged in Zajdela hepatoma cells since the latter was not detected until 24 h, while the transition from the 100-kDa precursor to the 115-kDa mature form began within 3 h in normal rat hepatocytes. Digestion of both the normal rat hepatocytes and Zajdela hepatoma cells 100-kDa beta 1-precursors with endo-beta-N-acetylglucosaminidase H and peptide N-glycosidase yielded products from 100 kDa to 84 kDa and 82 kDa, respectively, as judged by SDS/PAGE, suggesting that the same polypeptide chain is synthesized in normal rat hepatocytes and in Zajdela hepatoma cells. Incubation of the mature normal rat hepatocyte beta 1-subunit with peptide N-glycosidase reduced its molecular mass from 115 kDa to 82 kDa, as judged by SDS/PAGE, while the molecular mass of the abnormal mature Zajdela hepatoma cell beta 1-subunit decreased from 130 to 110 kDa. Thus, in addition to alterations in the Asn-linked oligosaccharide processing, 'ascitic growth' induced other post-translational modifications in the Zajdela hepatoma cell beta 1-subunit

  2. Brain oedema in focal ischaemia: molecular pathophysiology and theoretical implications

    PubMed Central

    Simard, J Marc; Kent, Thomas A; Chen, Mingkui; Tarasov, Kirill V; Gerzanich, Volodymyr

    2009-01-01

    Focal cerebral ischaemia and post-ischaemic reperfusion cause cerebral capillary dysfunction, resulting in oedema formation and haemorrhagic conversion. There are substantial gaps in understanding the pathophysiology, especially regarding early molecular participants. Here, we review physiological and molecular mechanisms involved. We reaffirm the central role of Starling's principle, which states that oedema formation is determined by the driving force and the capillary “permeability pore”. We emphasise that the movement of fluids is largely driven without new expenditure of energy by the ischaemic brain. We organise the progressive changes in osmotic and hydrostatic conductivity of abnormal capillaries into three phases: formation of ionic oedema, formation of vasogenic oedema, and catastrophic failure with haemorrhagic conversion. We suggest a new theory suggesting that ischaemia-induced capillary dysfunction can be attributed to de novo synthesis of a specific ensemble of proteins that determine osmotic and hydraulic conductivity in Starling's equation, and whose expression is driven by a distinct transcriptional program. PMID:17303532

  3. Sighting optics including an optical element having a first focal length and a second focal length

    DOEpatents

    Crandall, David Lynn

    2011-08-01

    One embodiment of sighting optics according to the teachings provided herein may include a front sight and a rear sight positioned in spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus, for a user, images of the front sight and the target.

  4. Cellular fibronectin 1 promotes VEGF-C expression, lymphangiogenesis and lymph node metastasis associated with human oral squamous cell carcinoma.

    PubMed

    Morita, Yoshihiro; Hata, Kenji; Nakanishi, Masako; Omata, Tetsuji; Morita, Nobuo; Yura, Yoshiaki; Nishimura, Riko; Yoneda, Toshiyuki

    2015-10-01

    Lymph node metastasis (LNM) is associated with poor survival in patients with oral squamous cell carcinoma (OSCC). Vascular endothelial growth factor-C (VEGF-C) is thought to be responsible for increased lymphangiogenesis and LNM. Understanding of the mechanism by which VEGF-C expression is regulated in OSCC is thus important to design logic therapeutic interventions. We showed that inoculation of the SAS human OSCC cells expressing the venus GFP (V-SAS cells) into the tongue in nude mice developed LNM. V-SAS cells in LNM were isolated by FACS and re-inoculated into the tongue. This procedure was repeated eight times, establishing V-SAS-LM8 cells. Differential metastasis PCR array between the parental V-SAS and V-SAS-LM8 was performed to identify a molecule responsible for lymphangiogenesis and LNM. Fibronectin 1 (FN1) expression was elevated in V-SAS-LM8 cells compared to V-SAS-cells. V-SAS-LM8 tongue tumor showed increased expression of FN1 and VEGF-C, and promoted lymphangiogenesis and LNM compared with V-SAS tumor. Further, phosphorylation of focal adhesion kinase (FAK), a main downstream signaling molecule of FN1, was up-regulated, and epithelial-mesenchymal transition (EMT) was promoted in V-SAS-LM8 cells. Silencing of FN1 by shRNA in V-SAS-LM8 cells decreased FAK phosphorylation, VEGF-C expression and inhibited lymphangiogenesis and LNM. EMT was also reversed. The FAK phosphorylation inhibitor PF573228 also decreased VEGF-C expression and reversed EMT in V-SAS-LM8 cells. Finally, we detected intense FN1 expression in some clinical specimens obtained from OSCC patients with LNM. These results demonstrate that elevated expression of cellular FN1 and following activation of FAK lead to increased VEGF-C expression, lymphangiogenesis and LNM and promoted EMT in SAS human OSCC cells and suggest that FN1-phosphorylated FAK signaling cascade is a potential therapeutic target in the treatment of LNM in OSCC. PMID:26319373

  5. Role of a bacillus Calmette-Guérin fibronectin attachment protein in BCG-induced antitumor activity.

    PubMed

    Zhao, W; Schorey, J S; Bong-Mastek, M; Ritchey, J; Brown, E J; Ratliff, T L

    2000-04-01

    Intravesical Mycobacterium bovis bacillus Calmette-Gu*erin (BCG) is the treatment of choice for superficial bladder cancer. Previous studies showed that attachment of BCG to fibronectin within the bladder was necessary for mediation of the antitumor response. Further studies identified a bacterial receptor, fibronectin attachment protein (FAP), as an important mediator of BCG attachment to fibronectin. In vitro studies showed that a stable BCG/fibronectin interaction was dependent on FAP binding to fibronectin; however, no role for FAP in the attachment of BCG in vivo has been characterized. We now report the cloning of the M. bovis BCG FAP (FAP-B) and demonstrate an important role for FAP in the in vivo attachment of BCG to the bladder wall and in the induction of BCG-mediated antitumor activity. The predicted amino acid sequence for FAP-B shows 61% and 71% homology, respectively, with Mycobacterium avium FAP (FAP-A) and Mycobacterium leprae FAP (FAP-L). Rabbit polyclonal antibodies against Mycobacterium vaccae FAP (FAP-V) reacted with all 3 recombinant FAP proteins on Western blots. Functional studies show FAP-B to bind fibronectin via the highly conserved attachment regions previously identified for FAP-A and FAP-L and also to competitively inhibit attachment of BCG to matrix fibronectin. In vivo studies show FAP to be a necessary protein for the stable attachment of BCG to the bladder wall. Moreover, stable binding of BCG via FAP was shown to be necessary for the expression of BCG-induced antitumor activity. Our results demonstrate a biological role for FAP in the mediation of BCG-induced antitumor activity. PMID:10728599

  6. The extracellular matrix proteins laminin and fibronectin contain binding domains for human plasminogen and tissue plasminogen activator.

    PubMed

    Moser, T L; Enghild, J J; Pizzo, S V; Stack, M S

    1993-09-01

    This study describes the binding of plasminogen and tissue-type plasminogen activator (t-PA) to the extracellular matrix proteins fibronectin and laminin. Plasminogen bound specifically and saturably to both fibronectin and laminin immobilized on microtiter wells, with Kd(app) values of 115 and 18 nM, respectively. Limited proteolysis by endoproteinase V8 coupled with ligand blotting analysis showed that both plasminogen and t-PA preferentially bind to a 55-kDa fibronectin fragment and a 38-kDa laminin fragment. Amino acid sequence analysis demonstrated that the 5-kDa fragment originates with the fibronectin amino terminus whereas the laminin fragment was derived from the carboxyl-terminal globular domain of the laminin A chain. Ligand blotting experiments using isolated plasminogen domains were also used to identify distinct regions of the plasminogen molecule involved in fibronectin and laminin binding. Solution phase fibronectin binding to immobilized plasminogen was mediated primarily via lysine binding site-dependent interactions with plasminogen kringles 1-4. Lysine binding site-dependent binding of soluble laminin to immobilized plasminogen kringles 1-5 as well as an additional lysine binding site-independent interaction between mini-plasminogen and the 38-kDa laminin A chain fragment were also observed. These studies demonstrate binding of plasminogen and tissue-type plasminogen activator to specific regions of the extracellular matrix glycoproteins laminin and fibronectin and provide further insight into the mechanism of regulation of plasminogen activation by components of the extracellular matrix. PMID:8360181

  7. Focal Mechanism determination of local M

    NASA Astrophysics Data System (ADS)

    Vales, Dina; Custório, Susana; Carrilho, Fernando

    2015-04-01

    We determine the focal mechanisms of local small (ML<3.9) earthquakes that occurred between 2013 and 2014 in mainland Portugal. These low magnitude events were recorded by several stations that provide first-motion polarity solutions. However, only few stations are located near the epicenter and record a waveform with a signal-to-noise ratio (SNR) high enough to allow full waveform modelling. To overcome this limitation, we used a new approach called cyclic scanning of the polarity solutions (CSPS) (Fojtíková and Zahradnik, 2014), which performs a joint inversion of full waveform and first motion polarities to retrieve the focal mechanism. This methodology has the advantage of yielding reliable focal mechanism solutions, even when high SNR waveforms are available from only a few near field stations (or in the limiting case, only with one single station). To apply the CSPS method one needs to: i) run the the FOCal MEChanism (FOCMEC) code (Snoke, 2003) to obtain a suite of the DC solutions corresponding to the first motion polarities, and then ii) perform the waveform modelling in order to decrease the uncertainty. The ISOLated Asperities (ISOLA) software (Sokos and Zahradník, 2008, 2013) is used in this second step. We applied this method to weak events recorded by a network of 30 broadband seismic stations that transmit data in real-time to Instituto Português do Mar e da Atmosfera (IPMA), the institution responsible for seismic monitoring in Portugal. We interpret the obtained fault plane solutions in light of active faults and regional tectonics, and in comparison with focal mechanisms previously inferred for events in the region. The focal mechanisms obtained for small earthquakes allow us to significantly expand the database of available focal mechanisms in mainland Portugal, contributing to the understanding of active deformation in the region.

  8. NMDA receptor binding in focal epilepsies

    PubMed Central

    McGinnity, C J; Koepp, M J; Hammers, A; Riaño Barros, D A; Pressler, R M; Luthra, S; Jones, P A; Trigg, W; Micallef, C; Symms, M R; Brooks, D J; Duncan, J S

    2015-01-01

    Objective To demonstrate altered N-methyl-d-aspartate (NMDA) receptor availability in patients with focal epilepsies using positron emission tomography (PET) and [18F]GE-179, a ligand that selectively binds to the open NMDA receptor ion channel, which is thought to be overactive in epilepsy. Methods Eleven patients (median age 33 years, 6 males) with known frequent interictal epileptiform discharges had an [18F]GE-179 PET scan, in a cross-sectional study. MRI showed a focal lesion but discordant EEG changes in two, was non-localising with multifocal EEG abnormalities in two, and was normal in the remaining seven patients who all had multifocal EEG changes. Individual patient [18F]GE-179 volume-of-distribution (VT) images were compared between individual patients and a group of 10 healthy controls (47 years, 7 males) using Statistical Parametric Mapping. Results Individual analyses revealed a single cluster of focal VT increase in four patients; one with a single and one with multifocal MRI lesions, and two with normal MRIs. Post hoc analysis revealed that, relative to controls, patients not taking antidepressants had globally increased [18F]GE-179 VT (+28%; p<0.002), and the three patients taking an antidepressant drug had globally reduced [18F]GE-179 VT (−29%; p<0.002). There were no focal abnormalities common to the epilepsy group. Conclusions In patients with focal epilepsies, we detected primarily global increases of [18F]GE-179 VT consistent with increased NMDA channel activation, but reduced availability in those taking antidepressant drugs, consistent with a possible mode of action of this class of drugs. [18F]GE-179 PET showed focal accentuations of NMDA binding in 4 out of 11 patients, with difficult to localise and treat focal epilepsy. PMID:25991402

  9. Workforce. Focal Point: Research, Policy, and Practice in Children's Mental Health. Volume 22, Number 1, Winter 2008

    ERIC Educational Resources Information Center

    Walker, Janet S., Ed.; Gowen, L. Kris, Ed.; Aue, Nicole, Ed.

    2008-01-01

    This issue of "Focal Point" explores how the increasing emphasis on using evidence-based practices and a "system of care" approach is driving changes in jobs and roles related to children's mental health. Articles in the issue describe how agencies and providers of services and supports have responded to these changes by creating new types of…

  10. Extended Driving Impairs Nocturnal Driving Performances

    PubMed Central

    Sagaspe, Patricia; Taillard, Jacques; Åkerstedt, Torbjorn; Bayon, Virginie; Espié, Stéphane; Chaumet, Guillaume; Bioulac, Bernard; Philip, Pierre

    2008-01-01

    Though fatigue and sleepiness at the wheel are well-known risk factors for traffic accidents, many drivers combine extended driving and sleep deprivation. Fatigue-related accidents occur mainly at night but there is no experimental data available to determine if the duration of prior driving affects driving performance at night. Participants drove in 3 nocturnal driving sessions (3–5am, 1–5am and 9pm–5am) on open highway. Fourteen young healthy men (mean age [±SD] = 23.4 [±1.7] years) participated Inappropriate line crossings (ILC) in the last hour of driving of each session, sleep variables, self-perceived fatigue and sleepiness were measured. Compared to the short (3–5am) driving session, the incidence rate ratio of inappropriate line crossings increased by 2.6 (95% CI, 1.1 to 6.0; P<.05) for the intermediate (1–5am) driving session and by 4.0 (CI, 1.7 to 9.4; P<.001) for the long (9pm–5am) driving session. Compared to the reference session (9–10pm), the incidence rate ratio of inappropriate line crossings were 6.0 (95% CI, 2.3 to 15.5; P<.001), 15.4 (CI, 4.6 to 51.5; P<.001) and 24.3 (CI, 7.4 to 79.5; P<.001), respectively, for the three different durations of driving. Self-rated fatigue and sleepiness scores were both positively correlated to driving impairment in the intermediate and long duration sessions (P<.05) and increased significantly during the nocturnal driving sessions compared to the reference session (P<.01). At night, extended driving impairs driving performances and therefore should be limited. PMID:18941525

  11. Focal Plane Metrology for the LSST Camera

    SciTech Connect

    A Rasmussen, Andrew P.; Hale, Layton; Kim, Peter; Lee, Eric; Perl, Martin; Schindler, Rafe; Takacs, Peter; Thurston, Timothy; /SLAC

    2007-01-10

    Meeting the science goals for the Large Synoptic Survey Telescope (LSST) translates into a demanding set of imaging performance requirements for the optical system over a wide (3.5{sup o}) field of view. In turn, meeting those imaging requirements necessitates maintaining precise control of the focal plane surface (10 {micro}m P-V) over the entire field of view (640 mm diameter) at the operating temperature (T {approx} -100 C) and over the operational elevation angle range. We briefly describe the hierarchical design approach for the LSST Camera focal plane and the baseline design for assembling the flat focal plane at room temperature. Preliminary results of gravity load and thermal distortion calculations are provided, and early metrological verification of candidate materials under cold thermal conditions are presented. A detailed, generalized method for stitching together sparse metrology data originating from differential, non-contact metrological data acquisition spanning multiple (non-continuous) sensor surfaces making up the focal plane, is described and demonstrated. Finally, we describe some in situ alignment verification alternatives, some of which may be integrated into the camera's focal plane.

  12. Maturational changes in laminin, fibronectin, collagen IV, and perlecan in germinal matrix, cortex, and white matter and effect of betamethasone.

    PubMed

    Xu, Hongmin; Hu, Furong; Sado, Yoshikazu; Ninomiya, Yoshifumi; Borza, Dorin-Bogdan; Ungvari, Zoltan; Lagamma, Edmund F; Csiszar, Anna; Nedergaard, Maiken; Ballabh, Praveen

    2008-05-15

    Germinal matrix is selectively vulnerable to hemorrhage in premature infants, and use of prenatal betamethasone is associated with a lower occurrence of germinal matrix hemorrhage. Because the major components of extracellular matrix of the cerebral vasculature-laminin, fibronectin, collagen IV, and perlecan-provide structural stability to blood vessels, we examined whether the expression of these molecules was decreased in the germinal matrix and affected by betamethasone. In both human fetuses and premature infants, fibronectin was significantly lower in the germinal matrix than in the cortical mantle or white matter anlagen. Conversely, laminin alpha1 gene expression was greater in the human germinal matrix compared with the cortical mantle or white matter. Expression of alpha1- and alpha2(IV) collagen chains increased with advancing gestational age. Low-dose prenatal betamethasone treatment enhanced fibronectin level by 1.5-2-fold whereas a high dose reduced fibronectin expression by 2-fold in rabbit pups. Because fibronectin provides structural stability to the blood vessels, its reduced expression in the germinal matrix may contribute to the fragility of germinal matrix vasculature and the propensity to hemorrhage in premature neonates. PMID:18214989

  13. Interleukin-8 down-regulates the oxidative burst induced by tumor necrosis factor alpha in neutrophils adherent to fibronectin.

    PubMed

    Ottonello, L; Lindley, I J; Pastorino, G; Dapino, P; Dallegri, F

    1994-01-01

    Human neutrophils (5 x 10(4) incubated on fibronectin precoated wells released 2.83 +/- .25 nmoles of superoxide (0(2)-) (x +/- 1 SEM, n = 15) in response to 5.9 nM (100 ng/ml) Tumor Necrosis Factor Alpha (TNF). On the contrary, the 0(2)- production induced by interleukin-8 (IL-8) (doses ranging from 0.1 nM to 1 microM) was comparable to that of "resting" cells (< .6 nmoles/5 x 10(4) cells). IL-8 (100 nM) did not affect the TNF-dependent 0(2)- production when added with TNF at the beginning of the assay, but reduced it by approximately 80% when added with TNF on neutrophils previously incubated for 1 hour on fibronectin. As compared with IL-8, N-formyl-methionyl-leucyl-phenylalanine (FMLP, 100 nM) failed to suppress the TNF-triggering of the oxidative burst in neutrophils plated on fibronectin. The data suggest that the interaction of neutrophils with fibronectin uncovers the capacity of IL-8 to limit the cell response to TNF, without affecting the response to the combination of FMLP and TNF. Thus, although the chemotactic factors IL-8 and FMLP share the capacity of triggering the oxidative burst of neutrophils incubated in suspension, only IL-8 has the potential to down-regulate the responsiveness of fibronectin-adherent cells to TNF. PMID:8049357

  14. Fibronectin induction abrogates the BRAF inhibitor response of BRAF V600E/PTEN-null melanoma cells.

    PubMed

    Fedorenko, I V; Abel, E V; Koomen, J M; Fang, B; Wood, E R; Chen, Y A; Fisher, K J; Iyengar, S; Dahlman, K B; Wargo, J A; Flaherty, K T; Sosman, J A; Sondak, V K; Messina, J L; Gibney, G T; Smalley, K S M

    2016-03-10

    The mechanisms by which some melanoma cells adapt to Serine/threonine-protein kinase B-Raf (BRAF) inhibitor therapy are incompletely understood. In the present study, we used mass spectrometry-based phosphoproteomics to determine how BRAF inhibition remodeled the signaling network of melanoma cell lines that were BRAF mutant and PTEN null. Short-term BRAF inhibition was associated with marked changes in fibronectin-based adhesion signaling that were PTEN dependent. These effects were recapitulated through BRAF siRNA knockdown and following treatment with chemotherapeutic drugs. Increased fibronectin expression was also observed in mouse xenograft models as well as specimens from melanoma patients undergoing BRAF inhibitor treatment. Analysis of a melanoma tissue microarray showed loss of PTEN expression to predict for a lower overall survival, with a trend for even lower survival being seen when loss of fibronectin was included in the analysis. Mechanistically, the induction of fibronectin limited the responses of these PTEN-null melanoma cell lines to vemurafenib, with enhanced cytotoxicity observed following the knockdown of either fibronectin or its receptor α5β1 integrin. This in turn abrogated the cytotoxic response to BRAF inhibition via increased AKT signaling, which prevented the induction of cell death by maintaining the expression of the pro-survival protein Mcl-1. The protection conveyed by the induction of FN expression could be overcome through combined treatment with a BRAF and PI3K inhibitor. PMID:26073081

  15. Electrical drive for automobile

    SciTech Connect

    Fobbs, H.

    1980-09-16

    Electrical apparatus for driving an automobile is described that is comprised of a dc motor operationally connected to the rear axle through a drive shaft with the motor energized from storage batteries and recharged from alternators coupled to the drive shaft adjacent a clutch at the rear end of the automobile through an auxiliary drive shaft.

  16. Coaxial Redundant Drives

    NASA Technical Reports Server (NTRS)

    Brissette, R.

    1983-01-01

    Harmonic drives allow redundancy and high out put torque in small package. If main drive fails, standby drive takes over and produces torque along same axis as main drive. Uses include power units in robot for internal pipeline inspection, manipulators in deep submersible probes or other applications in which redundancy protects against costly failures.

  17. Solid-state curved focal plane arrays

    NASA Technical Reports Server (NTRS)

    Nikzad, Shouleh (Inventor); Hoenk, Michael (Inventor); Jones, Todd (Inventor)

    2010-01-01

    The present invention relates to curved focal plane arrays. More specifically, the present invention relates to a system and method for making solid-state curved focal plane arrays from standard and high-purity devices that may be matched to a given optical system. There are two ways to make a curved focal plane arrays starting with the fully fabricated device. One way, is to thin the device and conform it to a curvature. A second way, is to back-illuminate a thick device without making a thinned membrane. The thick device is a special class of devices; for example devices fabricated with high purity silicon. One surface of the device (the non VLSI fabricated surface, also referred to as the back surface) can be polished to form a curved surface.

  18. Measuring microfocus focal spots using digital radiography

    SciTech Connect

    Fry, David A

    2009-01-01

    Measurement of microfocus spot size can be important for several reasons: (1) Quality assurance during manufacture of microfocus tubes; (2) Tracking performance and stability of microfocus tubes; (3) Determining magnification (especially important for digital radiography where the native spatial resolution of the digital system is not adequate for the application); (4) Knowledge of unsharpness from the focal spot alone. The European Standard EN 12543-5 is based on a simple geometrical method of calculating focal spot size from unsharpness of high magnification film radiographs. When determining microfocus focal spot dimensions using unsharpness measurements both signal-to-noise (SNR) and magnification can be important. There is a maximum accuracy that is a function of SNR and therefore an optimal magnification. Greater than optimal magnification can be used but it will not increase accuracy.

  19. Peptide therapies for ocular surface disturbances based on fibronectin-integrin interactions.

    PubMed

    Nishida, Teruo; Inui, Makoto; Nomizu, Motoyoshi

    2015-07-01

    The condition of the corneal epithelium is a critical determinant of corneal transparency and clear vision. The corneal epithelium serves as a barrier to protect the eye from external insults, with its smooth surface being essential for its optical properties. Disorders of the corneal epithelium include superficial punctate keratopathy, corneal erosion, and persistent epithelial defects (PEDs). The prompt resolution of these disorders is important for minimization of further damage to the cornea. Currently available treatment modalities for corneal epithelial disorders are based on protection of the ocular surface in order to allow natural healing to proceed. PEDs remain among the most difficult corneal conditions to treat, however. On the basis of characterization of the pathobiology of PEDs at the cell and molecular biological levels, we have strived to develop new modes of treatment for these defects. These treatments rely on two key concepts: provision of a substrate, such as the adhesive glycoprotein fibronectin, for the attachment and migration of corneal epithelial cells, and activation of these cells by biological agents such as the combination of substance P and insulin-like growth factor-1 (IGF-1). Central to both approaches is the role of the fibronectin-integrin system in corneal epithelial wound healing. Determination of the minimum amino acid sequences required for the promotion of corneal epithelial wound closure by fibronectin (PHSRN) and by substance P (FGLM-amide) plus IGF-1 (SSSR) has led to the development of peptide eyedrops for the treatment of PEDs that are free of adverse effects of the parent molecules. PMID:25645519

  20. Novel Potential Interacting Partners of Fibronectin in Spontaneous Animal Model of Interstitial Cystitis

    PubMed Central

    Treutlein, Gudrun; Dorsch, Roswitha; Euler, Kerstin N.; Hauck, Stefanie M.; Amann, Barbara; Hartmann, Katrin; Deeg, Cornelia A.

    2012-01-01

    Feline idiopathic cystitis (FIC) is the only spontaneous animal model for human interstitial cystitis (IC), as both possess a distinctive chronical and relapsing character. Underlying pathomechanisms of both diseases are not clearly established yet. We recently detected increased urine fibronectin levels in FIC cases. The purpose of this study was to gain further insight into the pathogenesis by assessing interacting partners of fibronectin in urine of FIC affected cats. Several candidate proteins were identified via immunoprecipitation and mass spectrometry. Considerable changes in FIC conditions compared to physiological expression of co-purified proteins were detected by Western blot and immunohistochemistry. Compared to controls, complement C4a and thioredoxin were present in higher levels in urine of FIC patients whereas loss of signal intensity was detected in FIC affected tissue. Galectin-7 was exclusively detected in urine of FIC cats, pointing to an important role of this molecule in FIC pathogenesis. Moderate physiological signal intensity of galectin-7 in transitional epithelium shifted to distinct expression in transitional epithelium under pathophysiological conditions. I-FABP expression was reduced in urine and urinary bladder tissue of FIC cats. Additionally, transduction molecules of thioredoxin, NF-κB p65 and p38 MAPK, were examined. In FIC affected tissue, colocalization of thioredoxin and NF-κB p65 could be demonstrated compared to absent coexpression of thioredoxin and p38 MAPK. These considerable changes in expression level and pattern point to an important role for co-purified proteins of fibronectin and thioredoxin-regulated signal transduction pathways in FIC pathogenesis. These results could provide a promising starting point for novel therapeutic approaches in the future. PMID:23236492

  1. Leishmania infection modulates beta-1 integrin activation and alters the kinetics of monocyte spreading over fibronectin

    PubMed Central

    Figueira, Cláudio Pereira; Carvalhal, Djalma Gomes Ferrão; Almeida, Rafaela Andrade; Hermida, Micely d’ El-Rei; Touchard, Dominique; Robert, Phillipe; Pierres, Anne; Bongrand, Pierre; dos-Santos, Washington LC

    2015-01-01

    Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue. In this work, we studied the early stages of bond formation between VLA4 and fibronectin, measured the kinetics of membrane alignment and the monocyte cytoplasm spreading area over a fibronectin-coated surface, and studied the expression of high affinity integrin epitope in uninfected and Leishmania-infected human monocytes. Our results show that the initial VLA4-mediated interaction of Leishmania-infected monocyte with a fibronectin-coated surface is preserved, however, the later stage, leukocyte spreading over the substrate is abrogated in Leishmania-infected cells. The median of spreading area was 72 [55–89] μm2 for uninfected and 41 [34–51] μm2 for Leishmania-infected monocyte. This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody. After the initial contact with the fibronectrin-coated surface, uninfected monocyte quickly spread the cytoplasm at a 15 μm2 s−1 ratio whilst Leishmania-infected monocytes only made small contacts at a 5.5 μm2 s−1 ratio. The expression of high affinity epitope by VLA4 (from 39 ± 21% to 14 ± 3%); and LFA1 (from 37 ± 32% to 18 ± 16%) molecules was reduced in Leishmania-infected monocytes. These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis. PMID:26249106

  2. Fibronectin-based scaffold domain proteins that bind myostatin: a patent evaluation of WO2014043344.

    PubMed

    Walker, Ryan G; Thompson, Thomas B

    2015-05-01

    Muscular dystrophies (MD) are commonly characterized by progressive loss of muscle mass and function. It is hypothesized that therapeutic blockade of the TGF-β ligand myostatin, a negative regulator of muscle mass, will stimulate muscle growth and restore muscle function. Although many anti-myostatin targets are currently being pursued in the clinical setting, the efficacies of the tested molecules have shown mixed results. The patent WO2014043344 describes a novel approach for myostatin inhibition using a modified fibronectin type III domain that could potentially be used to treat MD and other muscle-related pathologies. PMID:25632990

  3. [Effect of fibronectin on the synthesis of extracellular matrix proteins in periodontal ligament cells].

    PubMed

    Wan, L; Wu, Z; Zhou, Y

    1996-11-01

    Immunofluorescence staining method and fluorescence spectrophotometry were used to study the synthesis of extracellular matrix proteins in periodontal ligament cells (PDL cells) when exogenous fibronectin (FN) existed. The results showed that the right amount of exogenous FN (0.044 mumol/l) could increase the amount of type I collagen and type III collagen in PDL cells (P < 0.01), inhibit the synthesis of FN itself (P < 0.01). It suggested that exogenous FN can effect the synthesis of extracellular matrix proteins so as to promote a new connective tissue attachment formation. PMID:9592289

  4. EDA Fibronectin in Keloids Create a Vicious Cycle of Fibrotic Tumor Formation.

    PubMed

    Kelsh, Rhiannon M; McKeown-Longo, Paula J; Clark, Richard A F

    2015-07-01

    During the early phase of wound healing, first plasma fibronectin (FN) and then in situ FN are deposited at the site of injury. In situ FN--FN made by tissue cells at the injury site--often contains an extra domain A (EDA) insert. Multiple wound-related signal transduction pathways control the deposition of EDA FN, and the EDA insert can in turn trigger pathways that induce inflammation, increased extracellular matrix molecule deposition including FN and collagen, and activation of fibroblasts. Together these pathways can create a vicious cycle that leads to fibrosis or keloid formation. PMID:26066891

  5. Surface displaced alfa-enolase of Lactobacillus plantarum is a fibronectin binding protein

    PubMed Central

    Castaldo, Cristiana; Vastano, Valeria; Siciliano, Rosa Anna; Candela, Marco; Vici, Manuela; Muscariello, Lidia; Marasco, Rosangela; Sacco, Margherita

    2009-01-01

    Background Lactic acid bacteria of the genus Lactobacillus and Bifidobacterium are one of the most important health promoting groups of the human intestinal microbiota. Their protective role within the gut consists in out competing invading pathogens for ecological niches and metabolic substrates. Among the features necessary to provide health benefits, commensal microorganisms must have the ability to adhere to human intestinal cells and consequently to colonize the gut. Studies on mechanisms mediating adhesion of lactobacilli to human intestinal cells showed that factors involved in the interaction vary mostly among different species and strains, mainly regarding interaction between bacterial adhesins and extracellular matrix or mucus proteins. We have investigated the adhesive properties of Lactobacillus plantarum, a member of the human microbiota of healthy individuals. Results We show the identification of a Lactobacillus plantarum LM3 cell surface protein (48 kDa), which specifically binds to human fibronectin (Fn), an extracellular matrix protein. By means of mass spectrometric analysis this protein was identified as the product of the L. plantarum enoA1 gene, coding the EnoA1 alfa-enolase. Surface localization of EnoA1 was proved by immune electron microscopy. In the mutant strain LM3-CC1, carrying the enoA1 null mutation, the 48 kDa adhesin was not anymore detectable neither by anti-enolase Western blot nor by Fn-overlay immunoblotting assay. Moreover, by an adhesion assay we show that LM3-CC1 cells bind to fibronectin-coated surfaces less efficiently than wild type cells, thus demonstrating the significance of the surface displaced EnoA1 protein for the L. plantarum LM3 adhesion to fibronectin. Conclusion Adhesion to host tissues represents a crucial early step in the colonization process of either pathogens or commensal bacteria. We demonstrated the involvement of the L. plantarum Eno A1 alfa-enolase in Fn-binding, by studying LM3 and LM3-CC1 surface

  6. Solar array drive system

    NASA Technical Reports Server (NTRS)

    Berkopec, F. D.; Sturman, J. C.; Stanhouse, R. W.

    1976-01-01

    A solar array drive system consisting of a solar array drive mechanism and the corresponding solar array drive electronics is being developed. The principal feature of the solar array drive mechanism is its bidirectional capability which enables its use in mechanical redundancy. The solar array drive system is of a widely applicable design. This configuration will be tested to determine its acceptability for generic mission sets. Foremost of the testing to be performed is the testing for extended duration.

  7. Actinic Granuloma with Focal Segmental Glomerulosclerosis

    PubMed Central

    Phasukthaworn, Ruedee; Chanprapaph, Kumutnart; Vachiramon, Vasanop

    2016-01-01

    Actinic granuloma is an uncommon granulomatous disease, characterized by annular erythematous plaque with central clearing predominately located on sun-damaged skin. The pathogenesis is not well understood, ultraviolet radiation is recognized as precipitating factor. We report a case of a 52-year-old woman who presented with asymptomatic annular erythematous plaques on the forehead and both cheeks persisting for 2 years. The clinical presentation and histopathologic findings support the diagnosis of actinic granuloma. During that period of time, she also developed focal segmental glomerulosclerosis. The association between actinic granuloma and focal segmental glomerulosclerosis needs to be clarified by further studies. PMID:27293392

  8. Hybrid Extrinsic Silicon Focal Plane Architecture

    NASA Astrophysics Data System (ADS)

    Pommerrenig, D. H.; Meinhardt, T.; Lowe, J.

    1981-02-01

    Large-area focal planes require mechanical assembly techniques which must be compatible with optical alignment, minimum deadspace, and cryogenic requirements in order to achieve optimum performance. Hybrid extrinsic silicon has been found particularly suitable for such an application. It will be shown that by choosing a large-area extrinsic silicon detector array which is hybrid-mated to a multiplicity of multiplexers a very cost-effective and high-density focal plane module can be assembled. Other advantages of this approach are inherent optical alignment and excellent performance.

  9. Ambroxol-induced focal epileptic seizure.

    PubMed

    Lapenta, Leonardo; Morano, Alessandra; Fattouch, Jinane; Casciato, Sara; Fanella, Martina; Giallonardo, Anna Teresa; Di Bonaventura, Carlo

    2014-01-01

    It is well known that in epileptic patients some compounds and different drugs used for the treatment of comorbidities can facilitate or provoke seizures, this evidence regarding a wide spectrum of pharmacological categories. The potential facilitating factors usually include direct toxic effects or pharmacological interactions of either active ingredients or excipients. We report the case of a patient with drug-resistant epilepsy who experienced focal epileptic seizures, easily and constantly reproducible, after each administration of a cough syrup. This is, to our knowledge, the first electroencephalogram-documented case of focal epileptic seizures induced by cough syrup containing ambroxol as active ingredient. PMID:24824664

  10. [Liver ultrasound: focal lesions and diffuse diseases].

    PubMed

    Segura Grau, A; Valero López, I; Díaz Rodríguez, N; Segura Cabral, J M

    2016-01-01

    Liver ultrasound is frequently used as a first-line technique for the detection and characterization of the most common liver lesions, especially those incidentally found focal liver lesions, and for monitoring of chronic liver diseases. Ultrasound is not only used in the Bmode, but also with Doppler and, more recently, contrast-enhanced ultrasound. It is mainly used in the diagnosis of diffuse liver diseases, such as steatosis or cirrhosis. This article presents a practical approach for diagnosis workup, in which the different characteristics of the main focal liver lesions and diffuse liver diseases are reviewed. PMID:25523277

  11. Expression and function of a putative cell surface receptor for fibronectin in hamster and human cell lines

    SciTech Connect

    Brown, P.J.; Juliano, R.L.

    1986-10-01

    The authors have previously reported the use of monoclonal antibodies to identify a 140-kD cell surface glycoprotein in mammalian cells that is specifically involved in fibronectin-mediated cell adhesion. They now report the purification of this molecule using immunoaffinity chromatography and the subsequent generation of polyclonal antibodies that selectively immunoprecipitate 140-kD putative fibronectin receptor glycoprotein (gp140) extracted from rodent or human cells; these antibodies also specifically block fibronectin-mediated cell adhesion but not adhesion mediated by other factors in serum. Expression of gp140-like molecules was detected on the surfaces of several adherent human cell lines (HDF, WISH, and EFC) but not on erythrocytes; however, gp140 was also detected on a nonadherent human lymphoid line (DAUDI). Analysis of gp140 on nonreducing SDS gels revealed two closely migrating bands. Protease digestion and peptide mapping suggests that the two bnads are closely related polypeptides.

  12. Decipher the dynamic coordination between enzymatic activity and structural modulation at focal adhesions in living cells

    NASA Astrophysics Data System (ADS)

    Lu, Shaoying; Seong, Jihye; Wang, Yi; Chang, Shiou-Chi; Eichorst, John Paul; Ouyang, Mingxing; Li, Julie Y.-S.; Chien, Shu; Wang, Yingxiao

    2014-07-01

    Focal adhesions (FAs) are dynamic subcellular structures crucial for cell adhesion, migration and differentiation. It remains an enigma how enzymatic activities in these local complexes regulate their structural remodeling in live cells. Utilizing biosensors based on fluorescence resonance energy transfer (FRET), we developed a correlative FRET imaging microscopy (CFIM) approach to quantitatively analyze the subcellular coordination between the enzymatic Src activation and the structural FA disassembly. CFIM reveals that the Src kinase activity only within the microdomain of lipid rafts at the plasma membrane is coupled with FA dynamics. FA disassembly at cell periphery was linearly dependent on this raft-localized Src activity, although cells displayed heterogeneous levels of response to stimulation. Within lipid rafts, the time delay between Src activation and FA disassembly was 1.2 min in cells seeded on low fibronectin concentration ([FN]) and 4.3 min in cells on high [FN]. CFIM further showed that the level of Src-FA coupling, as well as the time delay, was regulated by cell-matrix interactions, as a tight enzyme-structure coupling occurred in FA populations mediated by integrin αvβ3, but not in those by integrin α5β1. Therefore, different FA subpopulations have distinctive regulation mechanisms between their local kinase activity and structural FA dynamics.

  13. The focal adhesion protein PINCH-1 associates with EPLIN at integrin adhesion sites

    PubMed Central

    Karaköse, Esra; Geiger, Tamar; Flynn, Kevin; Lorenz-Baath, Katrin; Zent, Roy; Mann, Matthias; Fässler, Reinhard

    2015-01-01

    ABSTRACT PINCH-1 is a LIM-only domain protein that forms a ternary complex with integrin-linked kinase (ILK) and parvin (to form the IPP complex) downstream of integrins. Here, we demonstrate that PINCH-1 (also known as Lims1) gene ablation in the epidermis of mice caused epidermal detachment from the basement membrane, epidermal hyperthickening and progressive hair loss. PINCH-1-deficient keratinocytes also displayed profound adhesion, spreading and migration defects in vitro that were substantially more severe than those of ILK-deficient keratinocytes indicating that PINCH-1 also exerts functions in an ILK-independent manner. By isolating the PINCH-1 interactome, the LIM-domain-containing and actin-binding protein epithelial protein lost in neoplasm (EPLIN, also known as LIMA1) was identified as a new PINCH-1-associated protein. EPLIN localized, in a PINCH-1-dependent manner, to integrin adhesion sites of keratinocytes in vivo and in vitro and its depletion severely attenuated keratinocyte spreading and migration on collagen and fibronectin without affecting PINCH-1 levels in focal adhesions. Given that the low PINCH-1 levels in ILK-deficient keratinocytes were sufficient to recruit EPLIN to integrin adhesions, our findings suggest that PINCH-1 regulates integrin-mediated adhesion of keratinocytes through the interactions with ILK as well as EPLIN. PMID:25609703

  14. Role of focal adhesions and mechanical stresses in the formation and progression of the lamellipodium-lamellum interface [corrected].

    PubMed

    Shemesh, Tom; Verkhovsky, Alexander B; Svitkina, Tatyana M; Bershadsky, Alexander D; Kozlov, Michael M

    2009-09-01

    Actin network in the front part of a moving cell is organized into a lamellipodium and a lamellum. A distinct lamellipodium-lamellum interface is associated with focal adhesions and consists of a series of arclike segments linking neighboring focal adhesions in the front row. The interface advances by leaping onto new rows of focal adhesions maturating underneath the lamellipodium. We propose a mechanism of the lamellipodium-lamellum boundary generation, shape formation, and progression based on the elastic stresses generated in the lamellipodial actin gel by its friction against the focal adhesions. The crucial assumption of the model is that stretching stresses trigger actin gel disintegration. We compute the stress distribution throughout the actin gel and show that the gel-disintegrating stresses drive formation of a gel boundary passing through the row of focal adhesions. Our computations recover the lamellipodium-lamellum boundary shapes detected in cells and predict the mode of the boundary transition to the row of the newly maturing focal adhesions in agreement with the experimental observations. The model fully accounts for the current phenomenology of the lamellipodium-lamellum interface formation and advancing, and makes experimentally testable predictions on the dependence of these phenomena on the sizes of the focal adhesions, the character of the focal adhesion distribution on the substrate, and the velocity of the actin retrograde flow with respect to the focal adhesions. The phase diagram resulting from the model provides a background for quantitative classification of different cell types with respect to their ability to form a lamellipodium-lamellum interface. In addition, the model suggests a mechanism of nucleation of the dorsal and arclike actin bundles found in the lamellum. PMID:19720013

  15. Coordinate regulation of fibronectin matrix assembly by the plasminogen activator system and vitronectin in human osteosarcoma cells

    PubMed Central

    Vial, Daniel; Monaghan-Benson, Elizabeth; McKeown-Longo, Paula J

    2006-01-01

    Background Plasminogen activators are known to play a key role in the remodeling of bone matrix which occurs during tumor progression, bone metastasis and bone growth. Dysfunctional remodeling of bone matrix gives rise to the osteoblastic and osteolytic lesions seen in association with metastatic cancers. The molecular mechanisms responsible for the development of these lesions are not well understood. Studies were undertaken to address the role of the plasminogen activator system in the regulation of fibronectin matrix assembly in the osteoblast-like cell line, MG-63. Results Treatment of MG-63 cells with P25, a peptide ligand for uPAR, resulted in an increase in assembly of fibronectin matrix which was associated with an increase in the number of activated β1 integrins on the cell surface. Overexpression of uPAR in MG-63 cells increased the effect of P25 on fibronectin matrix assembly and β1 integrin activation. P25 had no effect on uPAR null fibroblasts, confirming a role for uPAR in this process. The addition of plasminogen activator inhibitor Type I (PAI-1) to cells increased the P25-induced fibronectin polymerization, as well as the number of activated integrins. This positive regulation of PAI-1 on fibronectin assembly was independent of PAI-1's anti-proteinase activity, but acted through PAI-1 binding to the somatomedin B domain of vitronectin. Conclusion These results indicate that vitronectin modulates fibronectin matrix assembly in osteosarcoma cells through a novel mechanism involving cross-talk through the plasminogen activator system. PMID:16569238

  16. Regulation of ionizing radiation-induced adhesion of breast cancer cells to fibronectin by alpha5beta1 integrin.

    PubMed

    Lee, Shin Hee; Cheng, Huiwen; Yuan, Ye; Wu, Shiyong

    2014-06-01

    Ionizing radiation (IR) is commonly used for cancer therapy, however, its potential influence on cancer metastatic potential remains controversial. In this study, we elucidated the role of integrins in regulation of IR-altered adhesion between breast cancer cells and extracellular matrix (ECM) proteins, which is a key step in the initial phase of metastasis. Our data suggest that the extent of effect that ionizing radiation had on cell adhesion depended on the genetic background of the breast cancer cells. Ionizing radiation was a better adhesion inducer for p53-mutated cells, such as MDA-MB-231 cells, than for p53 wild-type cells, such as MCF-7 cells. While IR-induced adhesions between MDA-MB-231 cells to fibronectin, laminin, collagen I and collagen IV, only blocking of the adhesion between α5β1 integrin and fibronectin using anti-α5β1 integrin antibody could completely inhibit the radiation-induced adhesion of the cells. A soluble Arg-Gly-Asp peptide, the binding motif for fibronectin binding integrins, could also reduce the adhesion of the cells to fibronectin with or without ionizing radiation exposure. The inhibition of the cell-fibronectin interaction also affected, but did not always correlate with, transwell migration of the cancer cells. In addition, our data showed that the total expression of α5 integrin and surface expression of α5β1 integrin were increased in the cells treated with ionizing radiation. The increased surface expression of α5β1 integrin, along with the adhesion between the cells and fibronectin, could be inhibited by both ataxia telangiectasia mutated (ATM) and Rad3-related (ATR) kinase inhibitors. These results suggested that ATM/ATR-mediated surface expression of α5β1 integrin might play a central role in regulation of ionizing radiation-altered adhesion. PMID:24785587

  17. Nano-Stenciled RGD-Gold Patterns That Inhibit Focal Contact Maturation Induce Lamellipodia Formation in Fibroblasts

    PubMed Central

    Lutz, Roman; Pataky, Kristopher; Gadhari, Neha; Marelli, Mattia; Brugger, Juergen; Chiquet, Matthias

    2011-01-01

    Cultured fibroblasts adhere to extracellular substrates by means of cell-matrix adhesions that are assembled in a hierarchical way, thereby gaining in protein complexity and size. Here we asked how restricting the size of cell-matrix adhesions affects cell morphology and behavior. Using a nanostencil technique, culture substrates were patterned with gold squares of a width and spacing between 250 nm and 2 µm. The gold was functionalized with RGD peptide as ligand for cellular integrins, and mouse embryo fibroblasts were plated. Limiting the length of cell-matrix adhesions to 500 nm or less disturbed the maturation of vinculin-positive focal complexes into focal contacts and fibrillar adhesions, as indicated by poor recruitment of α5-integrin. We found that on sub-micrometer patterns, fibroblasts spread extensively, but did not polarize. Instead, they formed excessive numbers of lamellipodia and a fine actin meshwork without stress fibers. Moreover, these cells showed aberrant fibronectin fibrillogenesis, and their speed of directed migration was reduced significantly compared to fibroblasts on 2 µm square patterns. Interference with RhoA/ROCK signaling eliminated the pattern-dependent differences in cell morphology. Our results indicate that manipulating the maturation of cell-matrix adhesions by nanopatterned surfaces allows to influence morphology, actin dynamics, migration and ECM assembly of adhering fibroblasts. PMID:21980465

  18. Nano-stenciled RGD-gold patterns that inhibit focal contact maturation induce lamellipodia formation in fibroblasts.

    PubMed

    Lutz, Roman; Pataky, Kristopher; Gadhari, Neha; Marelli, Mattia; Brugger, Juergen; Chiquet, Matthias

    2011-01-01

    Cultured fibroblasts adhere to extracellular substrates by means of cell-matrix adhesions that are assembled in a hierarchical way, thereby gaining in protein complexity and size. Here we asked how restricting the size of cell-matrix adhesions affects cell morphology and behavior. Using a nanostencil technique, culture substrates were patterned with gold squares of a width and spacing between 250 nm and 2 µm. The gold was functionalized with RGD peptide as ligand for cellular integrins, and mouse embryo fibroblasts were plated. Limiting the length of cell-matrix adhesions to 500 nm or less disturbed the maturation of vinculin-positive focal complexes into focal contacts and fibrillar adhesions, as indicated by poor recruitment of α5-integrin. We found that on sub-micrometer patterns, fibroblasts spread extensively, but did not polarize. Instead, they formed excessive numbers of lamellipodia and a fine actin meshwork without stress fibers. Moreover, these cells showed aberrant fibronectin fibrillogenesis, and their speed of directed migration was reduced significantly compared to fibroblasts on 2 µm square patterns. Interference with RhoA/ROCK signaling eliminated the pattern-dependent differences in cell morphology. Our results indicate that manipulating the maturation of cell-matrix adhesions by nanopatterned surfaces allows to influence morphology, actin dynamics, migration and ECM assembly of adhering fibroblasts. PMID:21980465

  19. Data on cell spread area and directional contraction in human umbilical vein endothelial cells on fibronectin and on collagen type I-coated micro-posts

    PubMed Central

    Han, Jing-Jing; Tan, Hui-Foon; Feng, Chen; Wee, Wei-Kiat; Tee, Shang-You; Tan, Suet-Mien

    2016-01-01

    Fibronectin and collagen type I are abundant extracellular matrix proteins that modulate cell mechanics and they regulate angiogenic sprouting. In this data article, fibronectin- or collagen type I-coated micro-posts were used to examine the traction force, cell spread area and directional contraction of human umbilical vein endothelial cells (HUVECs). PMID:26937451

  20. Complex source description of focal regions.

    PubMed

    Monzon, Cesar; Forester, Donald W; Moore, Peter

    2006-04-01

    Closed-form solutions of the two-dimensional homogeneous wave equation are presented that provide focal-region descriptions corresponding to a converging bundle of rays. The solutions do have evanescent wave content and can be described as a source-sink pair or particle-antiparticle pair, collocated in complex space, with the complex location being critical in the determination of beam shape and focal region size. The wave solutions are not plagued by singularities, have a finite energy, and have a limitation on how small the focal size can get, with a penalty for limiting small spot sizes in the form of impractically high associated reactive energy. The electric-field-defined spot-size limiting value is 0.35lambda x 0.35lambda, which is about 38% of the Poynting-vector-defined minimum spot size (0.8lambda x 0.4lambda) and corresponds to a condition related to the maximum possible beam angle. A multiple set of solutions is introduced, and the elementary solutions are used to produce new solutions via superposition, resulting in fields with chiral character or with increased depth of focus. We do not claim generality, as the size of focal regions exhibited by the closed-form solutions has a lower bound and hence is not able to account for Pendry's "ideal lens" scenario. PMID:16604758

  1. Focal Dermal Hypoplasia: A Rare Case Report

    PubMed Central

    Srinivas, Sahana M; Hiremagalore, Ravi

    2015-01-01

    Focal dermal hypoplasia (Goltz syndrome) is a rare genetic multisystem disorder primarily involving the skin, skeletal system, eyes, and face. We report the case of an eight-month-old female child who presented with multiple hypopigmented atrophic macules along the lines of blaschko, skeletal anomalies, umbilical hernia, developmental delay, hypoplastic nails, syndactyly, and lobster claw deformity characteristic of Goltz syndrome. PMID:25657436

  2. MTI Focal Plane Assembly Design and Performance

    SciTech Connect

    Ballard, M.; Rienstra, J.L.

    1999-06-17

    The focal plane assembly for the Multispectral Thermal Imager (MTI) consists of sensor chip assemblies, optical filters, and a vacuum enclosure. Sensor chip assemblies, composed of linear detector arrays and readout integrated circuits, provide spatial resolution in the cross-track direction for the pushbroom imager. Optical filters define 15 spectral bands in a range from 0.45 {micro}m to 10.7 {micro}m. All the detector arrays are mounted on a single focal plane and are designed to operate at 75 K. Three pairs of sensor chip assemblies (SCAs) are required to provide cross-track coverage in all 15 spectral bands. Each pair of SCAs includes detector arrays made from silicon, iridium antimonide, and mercury cadmium telluride. Read out integrated circuits multiplex the signals from the detectors to 18 separate video channels. Optical filter assemblies defining the spectral bands are mounted over the linear detector arrays. Each filter assembly consists of several filter strips bonded together side-by-side. The MTI focal plane assembly has been integrated with the rest of the payload and has undergone detailed testing and calibration. This paper includes representative test data for the various spectral bands and the overall performance of the focal plane assembly.

  3. Optical interconnections to focal plane arrays

    SciTech Connect

    Rienstra, J.L.; Hinckley, M.K.

    2000-11-01

    The authors have successfully demonstrated an optical data interconnection from the output of a focal plane array to the downstream data acquisition electronics. The demonstrated approach included a continuous wave laser beam directed at a multiple quantum well reflectance modulator connected to the focal plane array analog output. The output waveform from the optical interconnect was observed on an oscilloscope to be a replica of the input signal. They fed the output of the optical data link to the same data acquisition system used to characterize focal plane array performance. Measurements of the signal to noise ratio at the input and output of the optical interconnection showed that the signal to noise ratio was reduced by a factor of 10 or more. Analysis of the noise and link gain showed that the primary contributors to the additional noise were laser intensity noise and photodetector receiver noise. Subsequent efforts should be able to reduce these noise sources considerably and should result in substantially improved signal to noise performance. They also observed significant photocurrent generation in the reflectance modulator that imposes a current load on the focal plane array output amplifier. This current loading is an issue with the demonstrated approach because it tends to negate the power saving feature of the reflectance modulator interconnection concept.

  4. Focal dermal hypoplasia: a rare case report.

    PubMed

    Srinivas, Sahana M; Hiremagalore, Ravi

    2015-01-01

    Focal dermal hypoplasia (Goltz syndrome) is a rare genetic multisystem disorder primarily involving the skin, skeletal system, eyes, and face. We report the case of an eight-month-old female child who presented with multiple hypopigmented atrophic macules along the lines of blaschko, skeletal anomalies, umbilical hernia, developmental delay, hypoplastic nails, syndactyly, and lobster claw deformity characteristic of Goltz syndrome. PMID:25657436

  5. Dual band QWIP focal plane array

    NASA Technical Reports Server (NTRS)

    Gunapala, Sarath D. (Inventor); Choi, Kwong Kit (Inventor); Bandara, Sumith V. (Inventor)

    2005-01-01

    A quantum well infrared photodetector (QWIP) that provides two-color image sensing. Two different quantum wells are configured to absorb two different wavelengths. The QWIPs are arrayed in a focal plane array (FPA). The two-color QWIPs are selected for readout by selective electrical contact with the two different QWIPs or by the use of two different wavelength sensitive gratings.

  6. Sensory-motor integration in focal dystonia.

    PubMed

    Avanzino, Laura; Tinazzi, Michele; Ionta, Silvio; Fiorio, Mirta

    2015-12-01

    Traditional definitions of focal dystonia point to its motor component, mainly affecting planning and execution of voluntary movements. However, focal dystonia is tightly linked also to sensory dysfunction. Accurate motor control requires an optimal processing of afferent inputs from different sensory systems, in particular visual and somatosensory (e.g., touch and proprioception). Several experimental studies indicate that sensory-motor integration - the process through which sensory information is used to plan, execute, and monitor movements - is impaired in focal dystonia. The neural degenerations associated with these alterations affect not only the basal ganglia-thalamic-frontal cortex loop, but also the parietal cortex and cerebellum. The present review outlines the experimental studies describing impaired sensory-motor integration in focal dystonia, establishes their relationship with changes in specific neural mechanisms, and provides new insight towards the implementation of novel intervention protocols. Based on the reviewed state-of-the-art evidence, the theoretical framework summarized in the present article will not only result in a better understanding of the pathophysiology of dystonia, but it will also lead to the development of new rehabilitation strategies. PMID:26164472

  7. Towards Dualband Megapixel QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Hill, C. J.; Rafol, S. B.; Salazar, D.; Woolaway, J.; LeVan, P. D.; Tidrow, M. Z.

    2006-01-01

    Mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) 1024 x 1024 pixel quantum well infrared photodetector (QWIP) focal planes have been demonstrated with excellent imaging performance. The MWIR QWIP detector array has demonstrated a noise equivalent differential temperature (NEDT) of 17 mK at a 95 K operating temperature with f/2.5 optics at 300 K background and the LWIR detector array has demonstrated a NEDT of 13 mK at a 70 K operating temperature with the same optical and background conditions as the MWIR detector array after the subtraction of system noise. Both MWIR and LWIR focal planes have shown background limited performance (BLIP) at 90 K and 70 K operating temperatures respectively, with similar optical and background conditions. In addition, we have demonstrated MWIR and LWIR pixel co-registered simultaneously readable dualband QWIP focal plane arrays. In this paper, we will discuss the performance in terms of quantum efficiency, NEDT, uniformity, operability, and modulation transfer functions of the 1024 x 1024 pixel arrays and the progress of dualband QWIP focal plane array development work.

  8. Large Format Multicolor QWIP Focal Plane Arrays

    NASA Technical Reports Server (NTRS)

    Soibel, A.; Gunapala, S. D.; Bandara, S. V.; Liu, J. K.; Mumolo, J. M.; Ting, D. Z.; Hill, C. J.; Nguyen, J.

    2009-01-01

    Mid-wave infrared (MWIR) and long-wave infrared (LWIR) multicolor focal plane array (FPA) cameras are essential for many DoD and NASA applications including Earth and planetary remote sensing. In this paper we summarize our recent development of large format multicolor QWIP FPA that cover MWIR and LWIR bands.

  9. Silibinin inhibits fibronectin induced motility, invasiveness and survival in human prostate carcinoma PC3 cells via targeting integrin signaling.

    PubMed

    Deep, Gagan; Kumar, Rahul; Jain, Anil K; Agarwal, Chapla; Agarwal, Rajesh

    2014-10-01

    Prostate cancer (PCA) is the 2nd leading cause of cancer-related deaths among men in the United States. Preventing or inhibiting metastasis-related events through non-toxic agents could be a useful approach for lowering high mortality among PCA patients. We have earlier reported that natural flavonoid silibinin possesses strong anti-metastatic efficacy against PCA however, mechanism/s of its action still remains largely unknown. One of the major events during metastasis is the replacement of cell-cell interaction with integrins-based cell-matrix interaction that controls motility, invasiveness and survival of cancer cells. Accordingly, here we examined silibinin effect on advanced human PCA PC3 cells' interaction with extracellular matrix component fibronectin. Silibinin (50-200 μM) treatment significantly decreased the fibronectin (5 μg/ml)-induced motile morphology via targeting actin cytoskeleton organization in PC3 cells. Silibinin also decreased the fibronectin-induced cell proliferation and motility but significantly increased cell death in PC3 cells. Silibinin also inhibited the PC3 cells invasiveness in Transwell invasion assays with fibronectin or cancer associated fibroblasts (CAFs) serving as chemoattractant. Importantly, PC3-luc cells cultured on fibronectin showed rapid dissemination and localized in lungs following tail vein injection in athymic male nude mice; however, in silibinin-treated PC3-luc cells, dissemination and lung localization was largely compromised. Molecular analyses revealed that silibinin treatment modulated the fibronectin-induced expression of integrins (α5, αV, β1 and β3), actin-remodeling (FAK, Src, GTPases, ARP2 and cortactin), apoptosis (cPARP and cleaved caspase 3), EMT (E-cadherin and β-catenin), and cell survival (survivin and Akt) related signaling molecules in PC3 cells. Furthermore, PC3-xenograft tissue analyses confirmed the inhibitory effect of silibinin on fibronectin and integrins expression. Together, these

  10. Adhesion of Staphylococcus epidermidis to biomaterials is inhibited by fibronectin and albumin

    PubMed Central

    Linnes, J.C.; Mikhova, K.; Bryers, J.D.

    2012-01-01

    Decades of contradictory results have obscured the exact role of adsorbed fibronectin in the adhesion of the bacterium, Staphylococcus epidermidis (S. epidermidis), to biomaterials. Here, the ability of adsorbed fibronectin (FN) or bovine serum albumin (BSA) to modulate S. epidermidis adhesion to various biomaterials is reported. FN or BSA were adsorbed in increasing surface densities up to saturated monolayer coverage onto various common biomaterials, including poly(ethylene terephthalate) (PET), fluorinated ethylene propylene (FEP), poly(ether urethane) (PEU), silicone, and borosilicate glass. Despite the wide range of surface characteristics represented, adsorption isotherms varied only subtly between materials for the two proteins considered. S. epidermidis adhesion to the various protein-coated biomaterials was quantified in a static-fluid batch adhesion assay. While slight differences in overall adherent cell numbers were observed between the various protein-coated substrata, all materials exhibited significant dose-dependent decreases in S. epidermidis adhesion with increasing adsorption of either protein (FN, BSA) to all surfaces. Results here indicate that S. epidermidis adhesion to FN-coated surfaces is not a specific adhesion (i.e., receptor:ligand) mediated process, as no significant difference in adhesion was found between FN- and BSA-coated materials. Rather, results indicate that increasing surface density of either FN or BSA actually inhibited S. epidermidis adhesion to all biomaterials examined. PMID:22566405

  11. In Vitro and In Vivo investigations on fibronectin coated and hydroxyapatite incorporated scaffolds.

    PubMed

    Mohamadyar-Toupkanlou, F; Vasheghani-Farahani, E; Bakhshandeh, B; Soleimani, M; Ardeshirylajimi, A

    2015-01-01

    Topological and biochemical aspects of the matrices are essential factors to be extensively studied for more successful tissue engineering. Other characteristics including biodegradability and biocompatibility should be also considered. Nanofibrous structure mimics topography of the natural matrix. Previous in vitro studies reported the favorable effects of nanohydroxyapatite (nHA) and fibronectin (Fn) on biodegradability and biocompatibility of scaffold. Herein, the synergistic outcome of co-application of Fn and nHA incorporation into aligned electrospun polycaprolactone (PCL) seeded by mouse mesenchymal stem cells (MSC) was investigated both in vitro and in vivo. Scanning Electron Microscopy (SEM), contact angle measurement and tensile test were applied for scaffold characterization. In vitro evaluation of the seeded cells was performed by MTT, SEM and cell-cycle analyses. In congruence with in vitro findings, in vivo assessment of four weeks fibronectin coated PCL/ nHA scaffold transplanted mice illustrated the suitable compact surrounding tissue with the most penetrated cells generation. Furthermore, Fn coating resulted in cell infiltration enhancement while nHA addition led to more scaffold biodegradation. In conclusion, fabrication of nanofiberous scaffold with this combination of biochemical composition and surface stimulation caused improved biodegradability and biocompatibility of the scaffold which are desirable in more effective tissue regeneration. PMID:26255261

  12. A Biosynthetic Nerve Guide Conduit Based on Silk/SWNT/Fibronectin Nanocomposite for Peripheral Nerve Regeneration

    PubMed Central

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Zaminy, Arash; Kokabi, Mehrdad; Soleimani, Masoud; Mirahmadi, Fereshteh

    2013-01-01

    As a contribution to the functionality of nerve guide conduits (NGCs) in nerve tissue engineering, here we report a conduit processing technique through introduction and evaluation of topographical, physical and chemical cues. Porous structure of NGCs based on freeze-dried silk/single walled carbon nanotubes (SF/SWNTs) has shown a uniform chemical and physical structure with suitable electrical conductivity. Moreover, fibronectin (FN) containing nanofibers within the structure of SF/SWNT conduits produced through electrospinning process have shown aligned fashion with appropriate porosity and diameter. Moreover, fibronectin remained its bioactivity and influenced the adhesion and growth of U373 cell lines. The conduits were then implanted to 10 mm left sciatic nerve defects in rats. The histological assessment has shown that nerve regeneration has taken places in proximal region of implanted nerve after 5 weeks following surgery. Furthermore, nerve conduction velocities (NCV) and more myelinated axons were observed in SF/SWNT and SF/SWNT/FN groups after 5 weeks post implantation, indicating a functional recovery for the injured nerves. With immunohistochemistry, the higher S-100 expression of Schwann cells in SF/SWNT/FN conduits in comparison to other groups was confirmed. In conclusion, an oriented conduit of biocompatible SF/SWNT/FN has been fabricated with acceptable structure that is particularly applicable in nerve grafts. PMID:24098649

  13. A comparison of adsorbed and grafted fibronectin coatings under static and dynamic conditions.

    PubMed

    Montaño-Machado, Vanessa; Hugoni, Ludivine; Díaz-Rodríguez, Sergio; Tolouei, Ranna; Chevallier, Pascale; Pauthe, Emmanuel; Mantovani, Diego

    2016-09-21

    Coatings for medical devices are expected to improve their surface biocompatibility mainly by being bioactive, i.e. stimulating healing-oriented interactions with living cells, tissues and organs. In particular, for stent applications, coatings are often designed to enhance the endothelialization process. The coating strategy will be primarily responsible for the interfacial properties between the substrate and the coating, which must show high stability. Therefore, the present work aims at comparing the stability of adsorbed and grafted fibronectin, a protein well-known to promote endothelialization. Fibronectin coatings were deposited on fluorocarbon films generated by a plasma-based process on stainless steel substrates. Then, deformation tests were performed in order to simulate the stenting procedure and stability tests were completed under static and under-flow conditions. Coatings were characterized by XPS, AFM, water contact angle, immunostaining and ToF-SIMS analyses. The results show higher stability for the grafted coatings; indeed, the integrity of the protein simply adsorbed was strongly compromised especially after under-flow tests. Both coatings exhibited similar behavior after deformation and static tests. These results clearly show the impact of the coating strategy on the overall stability of the coatings as well as the importance of under-flow investigations. PMID:27546569

  14. MRI detection of breast cancer micrometastases with a fibronectin-targeting contrast agent

    PubMed Central

    Zhou, Zhuxian; Qutaish, Mohammed; Han, Zheng; Schur, Rebecca M.; Liu, Yiqiao; Wilson, David L.; Lu, Zheng-Rong

    2015-01-01

    Metastasis is the primary cause of death in breast cancer patients. Early detection of high-risk breast cancer, including micrometastasis, is critical in tailoring appropriate and effective interventional therapies. Increased fibronectin expression, a hallmark of epithelial-to-mesenchymal transition, is associated with high-risk breast cancer and metastasis. We have previously developed a penta-peptide CREKA (Cys-Arg-Glu-Lys-Ala)-targeted gadolinium-based magnetic resonance imaging (MRI) contrast agent, CREKA-Tris(Gd-DOTA)3 (Gd-DOTA (4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecyl gadolinium), which binds to fibrin–fibronectin complexes that are abundant in the tumour microenvironment of fast-growing breast cancer. Here we assess the capability of CREKA-Tris(Gd-DOTA)3 to detect micrometastasis with MRI in co-registration with high-resolution fluorescence cryo-imaging in female mice bearing metastatic 4T1 breast tumours. We find that CREKA-Tris(Gd-DOTA)3 provides robust contrast enhancement in the metastatic tumours and enables the detection of micrometastases of size <0.5 mm, extending the detection limit of the current clinical imaging modalities. These results demonstrate that molecular MRI with CREKA-Tris(Gd-DOTA)3 may facilitate early detection of high-risk breast cancer and micrometastasis in the clinic. PMID:26264658

  15. Two-Dimensional Motility of a Macrophage Cell Line on Microcontact-Printed Fibronectin

    PubMed Central

    Hind, Laurel E.; MacKay, Joanna L.; Cox, Dianne; Hammer, Daniel A.

    2014-01-01

    The ability of macrophages to migrate to sites of infection and inflammation is critical for their role in the innate immune response. Macrophage cell lines have made it possible to study the roles of individual proteins responsible for migration using molecular biology, but it has not been possible to reliably elicit the motility of macrophage cell lines in two-dimensions. In the past, measurements of the motility of macrophage cell lines have been largely limited to transwell assays which provide limited quantitative information on motility and limited ability to visualize cell morphology. We used microcontact printing to create polydimethylsiloxane (PDMS) surfaces functionalized with fibronectin that otherwise support little macrophage adhesion. We used these surfaces to measure macrophage migration in two-dimensions and found that these cells migrate efficiently in a uniform field of colony-stimulating factor-1, CSF-1. Knockdown of Cdc42 led to a non-statistically significant reduction in motility, whereas chemical inhibition of PI3K activity led to a complete loss of motility. Inhibition of the RhoA kinase, ROCK, did not abolish the motility of these cells but caused a quantitative change in motility, reducing motility significantly on high concentrations of fibronectin but not on low concentrations. This study illustrates the importance of studying cell motility on well controlled materials to better understand the exact roles of specific proteins on macrophage migration. PMID:25186818

  16. Fibronectin extra domain A (EDA) sustains CD133(+)/CD44(+) subpopulation of colorectal cancer cells.

    PubMed

    Ou, Juanjuan; Deng, Jia; Wei, Xing; Xie, Ganfeng; Zhou, Rongbin; Yu, Liqing; Liang, Houjie

    2013-09-01

    Fibronectin is a major extracellular matrix glycoprotein with several alternatively spliced variants, including extra domain A (EDA), which was demonstrated to promote tumorigenesis via stimulating angiogenesis and lymphangiogenesis. Given that CD133(+)/CD44(+) cancer cells are critical in tumorigenesis of colorectal cancer (CRC), we hypothesize that fibronectin EDA may promote tumorigenesis by sustaining the properties of CD133(+)/CD44(+) colon cancer cells. We found that tumor tissue and serum EDA levels are substantially higher in advanced versus early stage human CRC. Additionally we showed that tumor tissue EDA levels are positively correlated with differentiation status and chemoresistance, and correlated with a poor prognosis of CRC patients. We also showed that in colon cancer cells SW480, CD133(+)/CD44(+) versus CD133(-)/CD44(-) cells express significantly elevated EDA receptor integrin α9β1. Silencing EDA in SW480 cells reduces spheroid formation and cells positive for CD133 or CD44, which is associated with reduced expressions of embryonic stem cell markers and increased expressions of differentiation markers. Blocking integrin α9β1 function strongly reversed the effect of EDA overexpression. We also provided evidence suggesting that EDA sustains Wnt/β-catenin signaling activity via activating integrin/FAK/ERK pathway. In xenograft models, EDA-silenced SW480 cells exhibit reduced tumorigenic and metastatic capacity. In conclusion, EDA is essential for the maintenance of the properties of CD133(+)/CD44(+) colon cancer cells. PMID:23811539

  17. Alternatively Spliced EDA Domain of Fibronectin Is a Target for Pharmacodelivery Applications in Inflammatory Bowel Disease.

    PubMed

    Bootz, Franziska; Schmid, Anja Sophie; Neri, Dario

    2015-08-01

    The antibody-based pharmacodelivery of cytokines to sites of disease has been extensively studied for various indications but not for the treatment of inflammatory bowel diseases. Here, we report that the alternatively spliced EDA domain of fibronectin, a marker of angiogenesis and of tissue remodeling, is expressed in the dextran sodium sulfate mouse model of colitis and in patients with inflammatory bowel conditions, while being virtually undetectable in most normal adult tissues. Radiolabeled preparations of the F8 antibody, specific to the EDA domain of fibronectin, were shown to selectively localize to sites of inflammation in mice with colitis, as revealed by autoradiographic analysis. Fusion proteins of the F8 antibody with various murine payloads (interleukin-4, the p40 subunit of interleukin-12, interleukin-13) were administered to mice with colitis. IL12p40-F8 mediated an anti-inflammatory activity, which was comparable with the one of cyclosporine, whereas F8-IL4 did not inhibit colitis and F8-IL13 worsened the inflammatory conditions. PMID:25993691

  18. Fibronectin Splice Variation in Human Knee Cartilage, Meniscus and Synovial Membrane: Observations in Osteoarthritic Knee

    PubMed Central

    Scanzello, Carla R.; Markova, Dessislava Z.; Chee, Ana; Xiu, Yan; Adams, Sherrill L.; Anderson, Greg; Zgonis, Miltiadis; Qin, Ling; An, Howard S.; Zhang, Yejia

    2014-01-01

    Objective Fibronectin (FN) is a widely expressed molecule that can participate in development of osteoarthritis (OA) affecting cartilage, meniscus, and synovial membrane (SM). The alternatively spliced isoforms of FN in joint tissues other than cartilage have not been extensively studied previously. The present study compares FN splice variation in patients with varying degrees of osteoarthritic change. Design Joint tissues were collected from asymptomatic donors and patients undergoing arthroscopic procedures. Total RNA was amplified by PCR using primers flanking alternatively spliced Extra Domain A (EDA), Extra Domain B (EDB) and Variable (V) regions. Results EDB+, EDB− and EDA− and V+ variants were present in all joint tissues, while the EDA+ variant was rarely detected. Expression levels of EDB+ and EDV+ variants were similar in cartilage, synovium and meniscal tissues. Synovial expression of V+ FN in arthroscopy patients varied with degree of cartilage degeneration. Two V− isoforms, previously identified in cartilage, were also present in SM and meniscus. Conclusions Fibronectin splicing in meniscus and SM bears striking resemblance to that of cartilage. Expression levels of synovial V+ FN varied with degree of cartilage degeneration. V+ FN should be investigated as a potential biomarker of disease stage or progression in larger populations. PMID:25410897

  19. Interleukin 6 and fetal fibronectin as a predictors of preterm delivery in symptomatic patients

    PubMed Central

    Hadži-Lega, Marija; Markova, Ana Daneva; Stefanovic, Milan; Tanturovski, Mile

    2015-01-01

    Preterm delivery is the leading cause of neonatal mortality and morbidity. The rate of preterm births has been estimated to be about 15 million, which accounts for 11.1% of all live births worldwide. The purpose of this study was to evaluate the cervico-vaginal (CVF) cytokine IL-6 and fetal fibronectin (fFN) status as predictors of preterm delivery in patients with symptoms of preterm labor. Patients with symptoms suggestive of preterm labor were recruited from September 2013 to March 2014. Vaginal swabs were taken for fetal fibronectin test (fFN) and CVF IL-6. Antibiotics, steroids and tocolytics were administered, where appropriate. The outcome was measured by the occurrence of preterm delivery within 14 days from the day of hospital admission. Cut-off value of 1305 pg/mL for the concentration of IL-6 in the CVF was the best predictor of preterm delivery, with the sensitivity of 69.4% and specificity of 68.2%. Patients with positive fFN test had the OR of 6.429 (95%CI 1.991-20.758) to deliver prematurely. The multivariate analysis of combined fFN and CVF IL-6 tests resulted in risk of 86.7% to deliver prematurely, if both tests were positive. The combination of both tests performed better than the individual tests and decreased the false positive rate, which in turn reduced the chances for inappropriate patient treatment, bringing down the costs. PMID:25725144

  20. Hand2 ensures an appropriate environment for cardiac fusion by limiting Fibronectin function.

    PubMed

    Garavito-Aguilar, Zayra V; Riley, Heather E; Yelon, Deborah

    2010-10-01

    Heart formation requires the fusion of bilateral cardiomyocyte populations as they move towards the embryonic midline. The bHLH transcription factor Hand2 is essential for cardiac fusion; however, the effector genes that execute this function of Hand2 are unknown. Here, we provide in zebrafish the first evidence for a downstream component of the Hand2 pathway that mediates cardiac morphogenesis. Although hand2 is expressed in cardiomyocytes, mosaic analysis demonstrates that it plays a non-autonomous role in regulating cardiomyocyte movement. Gene expression profiles reveal heightened expression of fibronectin 1 (fn1) in hand2 mutant embryos. Reciprocally, overexpression of hand2 leads to decreased Fibronectin levels. Furthermore, reduction of fn1 function enables rescue of cardiac fusion in hand2 mutants: bilateral cardiomyocyte populations merge and exhibit improved tissue architecture, albeit without major changes in apicobasal polarity. Together, our data provide a novel example of a tissue creating a favorable environment for its morphogenesis: the Hand2 pathway establishes an appropriate environment for cardiac fusion through negative modulation of Fn1 levels. PMID:20724450

  1. Fibronectin glycation increases IGF-I induced proliferation of human aortic smooth muscle cells

    PubMed Central

    2012-01-01

    The advanced glycation end products, namely AGEs, contribute to long-termed complications of diabetes mellitus, including macroangiopathy, where smooth muscle cells (SMC) proliferation stimulated by platelet-derived growth factor (PDGF) isoforms and insulin-like growth factor-I (IGF-I) plays an important role. The objective of the present study was to investigate the effect of an AGE-modified extracellular matrix protein on IGF-I induced SMC proliferation and on the IGF-I-IGF binding protein 4 (IGFBP-4) axis under basal conditions and after stimulation with PDGF-BB. IGF-I resulted in significantly higher thymidine incorporation in SMC seeded on AGE-modified fibronectin (AGE-FN) in comparison to cells seeded on fibronectin (FN). This augmented proliferation could not be accounted for by increased expression of IGF-IR, by decreased secretion of IGFBP-4, a binding protein that inhibits IGF-I mitogenic effects or by increased IGF-IR autophosphorylation. PDGF-BB did not modulate IGF-IR and IGFBP-4 mRNA expression in any of the substrata, however, this growth factor elicited opposite effects on the IGFBP-4 content in the conditioned media, increasing it in cells plated on FN and diminishing it in cells plated on AGE-FN. These findings suggest that one mechanism by which AGE-modified proteins is involved in the pathogenesis of diabetes-associated atherosclerosis might be by increasing SMC susceptibility to IGF-I mitogenic effects. PMID:22553932

  2. Nano-TiO2 particles impair adhesion of airway epithelial cells to fibronectin

    PubMed Central

    Zarogiannis, Sotirios G.; Filippidis, Aristotelis S.; Fernandez, Solana; Jurkuvenaite, Asta; Ambalavanan, Namasivayam; Stanishevsky, Andrei; Vohra, Yogesh K.; Matalon, Sadis

    2016-01-01

    Titanium dioxide engineered nanoparticles (nano-TiO2) are widely used in the manufacturing of a number of products. Due to their size (<100 nm), when inhaled they may be deposited in the distal lung regions and damage Clara cells. We investigated the mechanisms by which short-term (one-hour) incubation of human airway Clara-like (H441) cells to nano-TiO2 (6 nm in diameter) alters the ability of H441 cells to adhere to extracellular matrix. Our results show that one h post incubation, there was a three fold increase of extracellular H2O2, increased intracellular oxidative stress as demonstrated by 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA) oxidation, and a five-fold increase of phosphor-ERK1/2 as measured by Western blotting. These changes were accompanied by a 25% decrease of H441 adherence to fibronectin (p<0.05 compared to vehicle incubated H441 cells). Pretreatment with the ERK1/2 inhibitor U0126 for three h, partially prevented this effect. In conclusion, short-term exposure of H441 cells to nano-TiO2 appears to reduce adherence to fibronectin due to oxidative stress and activation of ERK1/2. PMID:22947217

  3. Fibroblast cluster formation on 3D collagen matrices requires cell contraction dependent fibronectin matrix organization.

    PubMed

    da Rocha-Azevedo, Bruno; Ho, Chin-Han; Grinnell, Frederick

    2013-02-15

    Fibroblasts incubated on 3D collagen matrices in serum or lysophosphatidic acid (LPA)-containing medium self-organize into clusters through a mechanism that requires cell contraction. However, in platelet-derived growth factor (PDGF)-containing medium, cells migrate as individuals and do not form clusters even though they constantly encounter each other. Here, we present evidence that a required function of cell contraction in clustering is formation of fibronectin (FN) fibrillar matrix. We found that in serum or LPA but not in PDGF or basal medium, cells organized FN (both serum and cellular) into a fibrillar, detergent-insoluble matrix. Cell clusters developed concomitant with FN matrix formation. FN fibrils accumulated beneath cells and along the borders of cell clusters in regions of cell-matrix tension. Blocking Rho kinase or myosin II activity prevented FN matrix assembly and cell clustering. Using siRNA silencing and function-blocking antibodies and peptides, we found that cell clustering and FN matrix assembly required α5β1 integrins and fibronectin. Cells were still able to exert contractile force and compact the collagen matrix under the latter conditions, which showed that contraction was not sufficient for cell clustering to occur. Our findings provide new insights into how procontractile (serum/LPA) and promigratory (PDGF) growth factor environments can differentially regulate FN matrix assembly by fibroblasts interacting with collagen matrices and thereby influence mesenchymal cell morphogenetic behavior under physiologic circumstances such as wound repair, morphogenesis and malignancy. PMID:23117111

  4. Shotgun phage display of Lactobacillus casei BL23 against collagen and fibronectin.

    PubMed

    Munoz-Provencio, Diego; Monedero, Vicente

    2011-02-01

    Lactobacilli are normal constituents of the intestinal microbiota, and some strains show the capacity to bind to extracellular matrix proteins and components of the mucosal layer, which represents an adaptation to persist in this niche. A shotgun phage-display library of Lactobacillus casei BL23 was constructed and screened for peptides able to bind to fibronectin and collagen. Clones showing binding to these proteins were isolated, which encoded overlapping fragments of a putative transcriptional regulator (LCABL_29260), a hypothetical protein exclusively found in the L. casei/rhamnosus group (LCABL_01820), and a putative phage-related endolysin (LCABL_13470). The construction of different glutathione S-transferase (GST) fusions confirmed the binding activity and demonstrated that the three identified proteins could interact with fibronectin, fibrinogen, and collagen. The results illustrate the utility of phage display for the isolation of putative adhesins in lactobacilli. However, it remains to be determined whether the primary function of these proteins actually is adhesion to mucosal surfaces. PMID:21364304

  5. A beta 1-integrin receptor for fibronectin in human kidney glomeruli.

    PubMed Central

    Kerjaschki, D.; Ojha, P. P.; Susani, M.; Horvat, R.; Binder, S.; Hovorka, A.; Hillemanns, P.; Pytela, R.

    1989-01-01

    The fibronectin receptor (FNR) is a transmembrane heterodimeric glycoprotein which shares a common beta 1-chain with several other members of the integrin family of adhesion receptors. The authors have prepared a membrane fraction of isolated human glomeruli, from which two proteins (apparent molecular weights 120 kd and 140 kd) bound to a fibronectin-column, and were selectively released by the synthetic peptide Arg-Gly-Asp-Ser. These molecules were labeled in immune overlays by an antibody raised against the FNR from human placenta that recognizes both the FNR-specific a-chain and the group-specific beta 1-integrin chain. In sections of normal human kidneys this antibody labeled predominately the mesangia and the peripheral capillary walls of glomeruli by an immunoperoxidase procedure. Quantitative immunoelectron microscopy, using an indirect immunogold procedure, revealed a preferential localization along the cell membranes of mesangial, epithelial, and endothelial cells that face the mesangial matrix or the glomerular basement membrane (GBM). In kidney biopsies from patients with various glomerular diseases (membranous and other forms of glomerulonephritis, minimal change disease) the distribution was similar to that in normal glomeruli. These findings indicate that a beta 1-integrin-related FNR is present in normal and diseased human glomeruli. Images Figure 1-4 Figure 5 Figure 6-10 Figure 11-16 PMID:2521774

  6. Fibronectin Extra Domain A (EDA) Sustains CD133+/CD44+ Subpopulation of Colorectal Cancer Cells

    PubMed Central

    Ou, Juanjuan; Deng, Jia; Wei, Xing; Xie, Ganfeng; Zhou, Rongbin; Yu, Liqing; Liang, Houjie

    2013-01-01

    Fibronectin is a major extracellular matrix glycoprotein with several alternatively spliced variants, including extra domain A (EDA), which was demonstrated to promote tumorigenesis via stimulating angiogenesis and lymphangiogenesis. Given that CD133+/CD44+ cancer cells are critical in tumorigenesis of colorectal cancer (CRC), we hypothesize that fibronectin EDA may promote tumorigenesis by sustaining the properties of CD133+/CD44+ colon cancer cells. We found that tumor tissue and serum EDA levels are substantially higher in advanced versus early stage human CRC. Additionally we showed that tumor tissue EDA levels are positively correlated with differentiation status and chemoresistance, and correlated with a poor prognosis of CRC patients. We also showed that in colon cancer cells SW480, CD133+/CD44+ versus CD133−/CD44− cells express significantly elevated EDA receptor integrin α9β1. Silencing EDA in SW480 cells reduces spheroid formation and cells positive for CD133 or CD44, which is associated with reduced expressions of embryonic stem cell markers and increased expressions of differentiation markers. Blocking integrin α9β1 function strongly reversed the effect of EDA overexpression. We also provided evidence suggesting that EDA sustains Wnt/β-catenin signaling activity via activating integrin/FAK/ERK pathway. In xenograft models, EDA-silenced SW480 cells exhibit reduced tumorigenic and metastatic capacity. In conclusions, EDA is essential for the maintenance of the properties of CD133+/CD44+ colon cancer cells. PMID:23811539

  7. Genetic analysis of the cell binding domain region of the chicken fibronectin gene.

    PubMed

    Kubomura, S; Obara, M; Karasaki, Y; Taniguchi, H; Gotoh, S; Tsuda, T; Higashi, K; Ohsato, K; Hirano, H

    1987-11-20

    We have determined the nucleotide sequence of the cell binding domain region of the chicken fibronectin gene and analyzed it evolutionaly. We present here the complete nucleotide sequence of 4.3 kb HindIII/EcoRI segment from the clone lambda FC23 of the chicken fibronectin gene. There were five exons in this segment. When we lined up the amino acid of exons 28, 29 and 31, three alignments, known as the Type III repeat, appeared. Tetrapeptide, -RGDS-, called the cell binding domain, existed in the second repeat, coding exon 30. It was presumed that the Type III repeats were composed of two exons in the chicken gene, the same as in the rat and humans. We found repeatedly appearing amino-acid sequences such as -TIT- (three arrays in these Type III repeats) but also found one of the amino acids substituted in the tripeptide in these Type III repeats (seven arrays). We analyzed these repeats from the point of view of evolution. We used three of the nucleotide sequences (12-18 bp) coding such -TIT- repeats as a unit length for comparing the various homologies after dividing the coding region into 56 segments. The mutual homology of the divided segments to each one of three showed 53% on average. On the other hand, the mutual nucleotide homology of the Type III repeat was 44%. This suggested that the Type III repeat may have been developed by frequent duplication of small gene units. PMID:2823899

  8. Fetal Fibronectin

    MedlinePlus

    ... best Order bereavement materials News Moms Need Blog News & Media News Videos Mission stories Ambassadors Spotlights Tools & ... information about healthy pregnancies on your iPad. GO News Moms Need Blog Read about what moms and ...

  9. Hybridoma antibodies to the lipid-binding site(s) in the amino-terminal region of fibronectin inhibits binding of streptococcal lipoteichoic acid.

    PubMed

    Stanislawski, L; Courtney, H S; Simpson, W A; Hasty, D L; Beachey, E H; Robert, L; Ofek, I

    1987-08-01

    In this report, we present evidence to suggest that streptococci and lipoteichoic acid (LTA) interact with a fatty acid binding site located near the NH2-terminus of fibronectin. The evidence is based on the following observations. Antibodies directed against a synthetic peptide (residues 1-30 of the amino-terminus of fibronectin) reacted with the two thermolysin-generated peptides (24 and 28 kilodaltons [kDa]) that were adsorbed by and eluted from streptococci. The adsorption of the 24- and 28-kDa peptides to streptococci was inhibited by LTA. The two monoclonal antibodies that inhibited the binding of LTA to fibronectin reacted only with the 24- and 28-kDa fragments of fibronectin. Conversely, LTA, as well as lauric acid and oleic acid, blocked the binding of the same monoclonal antibodies to fibronectin. LTA had no effect on the binding of hybridoma antibodies directed against the collagen or cell-binding domain. PMID:3298457

  10. Driving and neurodegenerative diseases.

    PubMed

    Uc, Ergun Y; Rizzo, Matthew

    2008-09-01

    The proportion of elderly people in the general population is rising, resulting in greater numbers of drivers with neurodegenerative disorders such as Alzheimer's disease and Parkinson's disease. These neurodegenerative disorders impair cognition, visual perception, and motor function, leading to reduced driver fitness and greater crash risk. Yet neither medical diagnosis nor age alone is reliable enough to predict driver safety or crashes or to revoke the driving privileges of these individuals. Driving research utilizes tools such as questionnaires about driving habits and history, driving simulators, standardized road tests utilizing instrumented vehicles, and state driving records. Research challenges include outlining the evolution of driving safety, understanding the mechanisms of driving impairment, and developing a reliable and efficient standardized test battery for prediction of driver safety in neurodegenerative disorders. This information will enable healthcare providers to advise their patients with neurodegenerative disorders with more certainty, affect policy, and help develop rehabilitative measures for driving. PMID:18713573

  11. Gear bearing drive

    NASA Technical Reports Server (NTRS)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  12. Molecular Interactions of Human Plasminogen with Fibronectin-binding Protein B (FnBPB), a Fibrinogen/Fibronectin-binding Protein from Staphylococcus aureus.

    PubMed

    Pietrocola, Giampiero; Nobile, Giulia; Gianotti, Valentina; Zapotoczna, Marta; Foster, Timothy J; Geoghegan, Joan A; Speziale, Pietro

    2016-08-26

    Staphylococcus aureus is a commensal bacterium that has the ability to cause superficial and deep-seated infections. Like several other invasive pathogens, S. aureus can capture plasminogen from the human host where it can be converted to plasmin by host plasminogen activators or by endogenously expressed staphylokinase. This study demonstrates that sortase-anchored cell wall-associated proteins are responsible for capturing the bulk of bound plasminogen. Two cell wall-associated proteins, the fibrinogen- and fibronectin-binding proteins A and B, were found to bind plasminogen, and one of them, FnBPB, was studied in detail. Plasminogen captured on the surface of S. aureus- or Lactococcus lactis-expressing FnBPB could be activated to the potent serine protease plasmin by staphylokinase and tissue plasminogen activator. Plasminogen bound to recombinant FnBPB with a KD of 0.532 μm as determined by surface plasmon resonance. Plasminogen binding did not to occur by the same mechanism through which FnBPB binds to fibrinogen. Indeed, FnBPB could bind both ligands simultaneously indicating that their binding sites do not overlap. The N3 subdomain of FnBPB contains the full plasminogen-binding site, and this includes, at least in part, two conserved patches of surface-located lysine residues that were recognized by kringle 4 of the host protein. PMID:27387503

  13. Magnetic drive coupling

    NASA Technical Reports Server (NTRS)

    Carter, Edward L. (Inventor)

    1987-01-01

    The driving and driven members of a magnetic drive are separated by en enlarged gap to provide clearance for a conduit or other member. Flux pins in the gap maintain the torque transmitting capability of the drive. The spacing between two of the flux pins is increased to provide space for the conduit.

  14. Magnetic drive coupling

    NASA Technical Reports Server (NTRS)

    Carter, Edward L. (Inventor)

    1989-01-01

    The driving (30) and driven (32) members of a magnetic drive (20) are separated by an enlarged gap (35) to provide clearance for a conduit (23) or other member. Flux pins (40) in the gap (35) maintain the torque transmitting capability of the drive (20). The spacing between two of the flux pins is increased to provide space for the conduit (23).

  15. Sequential Dependencies in Driving

    ERIC Educational Resources Information Center

    Doshi, Anup; Tran, Cuong; Wilder, Matthew H.; Mozer, Michael C.; Trivedi, Mohan M.

    2012-01-01

    The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find…

  16. Grieving while Driving

    ERIC Educational Resources Information Center

    Rosenblatt, Paul C.

    2004-01-01

    Secondary analysis of data from 84 people in 2 interview studies shows that some bereaved people grieve actively while driving. The grief can be intense, even years after a death. Grief while driving may erupt spontaneously or be set off by a wide range of reminders. Some bereaved people seem to save their grieving for times when they drive,…

  17. Role of factor VIII-von Willebrand factor and fibronectin in the interaction of platelets in flowing blood with monomeric and fibrillar human collagen types I and III.

    PubMed

    Houdijk, W P; Sakariassen, K S; Nievelstein, P F; Sixma, J J

    1985-02-01

    Platelet adhesion to monomeric collagen types I and III, which were purified from human umbilical arteries, was studied in a perfusion chamber under well defined flow conditions. For this purpose, glass coverslips were coated with 20-30 micrograms/cm2 of collagen types I and III by spraying a solution of these collagens with a retouching air brush. Platelet deposition increased with the time of perfusion. Adhesion to both collagen types was similar in the first 3 min, but increased platelet deposition occurred on collagen type III after 3 min due to thrombus formation. Adhesion at a shear rate of 800 s-1 was strongly impaired with plasma of a patient with von Willebrand's disease or with fibronectin-free plasma. Addition of purified fibronectin to fibronectin-free plasma restored adhesion to the level obtained with normal plasma. Platelet deposition in normal plasma increased with increasing shear rates. Platelet deposition in VWD-plasma was normal at 490 s-1, but there was no increase at higher shear rates. Platelet deposition in fibronectin-free plasma was diminished at all shear rates studied from 490 to 1,300 s-1. Perfusion with a human albumin solution (HAS) to which purified Factor VIII-von Willebrand factor complex (FVIII-VWF) and fibronectin had been added gave similar platelet deposition as with normal plasma. Preincubation of collagen with FVIII-VWF and perfusion with HAS containing fibronectin, or, conversely, preincubation with fibronectin and perfusion with HAS containing FVIII-VWF, also resulted in adhesion similar to that observed in normal plasma. Similar adhesion was also observed after preincubation with both FVIII-VWF and fibronectin and subsequent perfusion with HAS alone. Sequential preincubations with first FVIII-VWF and then fibronectin, or with first fibronectin and then FVIII-VWF followed by perfusion with HAS, also gave a similar adhesion as observed with normal plasma. These data indicate that platelet adhesion to monomeric collagen types

  18. Role of factor VIII-von Willebrand factor and fibronectin in the interaction of platelets in flowing blood with monomeric and fibrillar human collagen types I and III.

    PubMed Central

    Houdijk, W P; Sakariassen, K S; Nievelstein, P F; Sixma, J J

    1985-01-01

    Platelet adhesion to monomeric collagen types I and III, which were purified from human umbilical arteries, was studied in a perfusion chamber under well defined flow conditions. For this purpose, glass coverslips were coated with 20-30 micrograms/cm2 of collagen types I and III by spraying a solution of these collagens with a retouching air brush. Platelet deposition increased with the time of perfusion. Adhesion to both collagen types was similar in the first 3 min, but increased platelet deposition occurred on collagen type III after 3 min due to thrombus formation. Adhesion at a shear rate of 800 s-1 was strongly impaired with plasma of a patient with von Willebrand's disease or with fibronectin-free plasma. Addition of purified fibronectin to fibronectin-free plasma restored adhesion to the level obtained with normal plasma. Platelet deposition in normal plasma increased with increasing shear rates. Platelet deposition in VWD-plasma was normal at 490 s-1, but there was no increase at higher shear rates. Platelet deposition in fibronectin-free plasma was diminished at all shear rates studied from 490 to 1,300 s-1. Perfusion with a human albumin solution (HAS) to which purified Factor VIII-von Willebrand factor complex (FVIII-VWF) and fibronectin had been added gave similar platelet deposition as with normal plasma. Preincubation of collagen with FVIII-VWF and perfusion with HAS containing fibronectin, or, conversely, preincubation with fibronectin and perfusion with HAS containing FVIII-VWF, also resulted in adhesion similar to that observed in normal plasma. Similar adhesion was also observed after preincubation with both FVIII-VWF and fibronectin and subsequent perfusion with HAS alone. Sequential preincubations with first FVIII-VWF and then fibronectin, or with first fibronectin and then FVIII-VWF followed by perfusion with HAS, also gave a similar adhesion as observed with normal plasma. These data indicate that platelet adhesion to monomeric collagen types

  19. Focal adhesion proteins connect IgE receptors to the cytoskeleton as revealed by micropatterned ligand arrays

    PubMed Central

    Torres, Alexis J.; Vasudevan, Lavanya; Holowka, David; Baird, Barbara A.

    2008-01-01

    Patterned surfaces that present specific ligands in spatially defined arrays are used to examine structural linkages between clustered IgE receptors (IgE-FcεRI) and the cytoskeleton in rat basophilic leukemia (RBL) mast cells. We showed with fluorescence microscopy that cytoskeletal F-actin concentrates in the same regions as cell surface IgE-FcεRI that bind to the micrometer-size patterned ligands. However, the proteins mediating these cytoskeletal connections and their functional relevance were not known. We now show that whereas the adaptor proteins ezrin and moesin do not detectably concentrate with the array of clustered IgE-FcεRI, focal adhesion proteins vinculin, paxillin, and talin, which are known to link F-actin with integrins, accumulate in these regions on the same time scale as F-actin. Moreover, colocalization of these focal adhesion proteins with clustered IgE-FcεRI is enhanced after addition of fibronectin-RGD peptides. Significantly, the most prominent rat basophilic leukemia cell integrin (α5) avoids the patterned regions occupied by the ligands and associates preferentially with exposed regions of the silicon substrate. Thus, spatial separation provided by the patterned surface reveals that particular focal adhesion proteins, which connect to the actin cytoskeleton, associate with ligand-cross-linked IgE-FcεRI, independently of integrins. We investigated the functional role of one of these proteins, paxillin, in IgE-FcεRI-mediated signaling by using small interfering RNA. From these results, we determine that paxillin reduces stimulated phosphorylation of the FcεRI β subunit but enhances stimulated Ca2+ release from intracellular stores. The results suggest that paxillin associated with clustered IgE-FcεRI has a net positive effect on FcεRI signaling. PMID:19004813

  20. THE FIBRONECTIN TYPE 3-LIKE REPEAT FROM THE CLOSTRIDIUM THERMOCELLUM CELLOBIOHYDROLASE CBHA PROMOTES HYDROLYSIS OF CELLULOSE BY MODIFYING ITS SURFACE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fibronectin type 3 homology domains (Fn3), as found in the cellobiohydrolase CbhA of Clostridium thermocellum, are common among bacterial extracellular glycohydrolases. The function of these domains is not clear. CbhA is modular and composed of an N-terminal family IV carbohydrate-binding domain (...

  1. The Fibronectin-Binding Protein EfbA Contributes to Pathogenesis and Protects against Infective Endocarditis Caused by Enterococcus faecalis

    PubMed Central

    Singh, Kavindra V.; La Rosa, Sabina Leanti; Somarajan, Sudha R.; Roh, Jung Hyeob

    2015-01-01

    EfbA is a PavA-like fibronectin adhesin of Enterococcus faecalis previously shown to be important in experimental urinary tract infection. Here, we expressed and purified the E. faecalis OG1RF EfbA and confirmed that this protein binds with high affinity to immobilized fibronectin, collagen I, and collagen V. We constructed an efbA deletion mutant and demonstrated that its virulence was significantly attenuated (P < 0.0006) versus the wild type in a mixed inoculum rat endocarditis model. Furthermore, efbA deletion resulted in diminished ability to bind fibronectin (P < 0.0001) and reduced biofilm (P < 0.001). Reintroduction of efbA into the original chromosomal location restored virulence, adherence to fibronectin, and biofilm formation to wild-type levels. Finally, vaccination of rats with purified recombinant EfbA protein protected against OG1RF endocarditis (P = 0.008 versus control). Taken together, our results demonstrate that EfbA is an important factor involved in E. faecalis endocarditis and that rEfbA immunization is effective in preventing such infection, likely by interfering with bacterial adherence. PMID:26351286

  2. EFFECT OF GROWTH FACTOR-FIBRONECTIN MATRIX INTERACTION ON RAT TYPE II CELL ADHESION AND DNA SYTHESIS

    EPA Science Inventory

    ABSTRACT

    Type II cells attach, migrate and proliferate on a provisional fibronectin-rich matrix during alveolar wall repair after lung injury. The combination of cell-substratum interactions via integrin receptors and exposure to local growth factors are likely to initiat...

  3. PDGF-A interactions with fibronectin reveal a critical role for heparan sulfate in directed cell migration during Xenopus gastrulation

    PubMed Central

    Smith, Erin M.; Mitsi, Maria; Nugent, Matthew A.; Symes, Karen

    2009-01-01

    Platelet-derived growth factor (PDGF) signaling is essential for processes involving cell motility and differentiation during embryonic development in a wide variety of organisms including the mouse, frog, zebrafish, and sea urchin. In early Xenopus laevis embryos, PDGF-AA provides guidance cues for the migration of anterior mesendoderm cells as they move across a fibronectin-rich extracellular matrix. The long form of PDGF-A includes a positively charged carboxyl-terminal retention motif that can interact with the extracellular matrix and heparan sulfate proteoglycans (HSPGs). In this study we demonstrate that PDGF-AA binds directly to fibronectin and that this association is greatly enhanced by heparin. The PDGF-AA-fibronectin binding occurs across a broad range of pHs (5.5–9), which is significant because the PDGF-guided migration of Xenopus mesendoderm cells occurs under basic extracellular conditions (pH 8.4). We further demonstrate that endogenous HSPG's are required for the PDGF-AA-guided mesendoderm movement, suggesting an in vivo role for HSPGs in mediating the interaction between PDGF-AA and fibronectin. PMID:19966216

  4. Identification of β integrin-like- and fibronectin-like proteins in the bivalve mollusk Mytilus trossulus.

    PubMed

    Dyachuk, Vyacheslav A; Maiorova, Maria A; Odintsova, Nelly A

    2015-09-01

    Integrins play a key role in the intermediation and coordination between cells and extracellular matrix components. In this study, we first determined the presence of the β integrin-like protein and its presumptive ligand, fibronectin-like protein, during development and in some adult tissues of the bivalve mollusc Mytilus trossulus. We found that β integrin-like protein expression correlated with the development and differentiation of the digestive system in larvae. Besides the presence of β integrin-like protein in the digestive epithelial larval cells, this protein was detected in the hemocytes and some adult tissues of M. trossulus. The fibronectin-like protein was detected firstly at the blastula stage and later, the FN-LP-immunoreactive cells were scattered in the trochophore larvae. The fibronectin-like protein was not expressed in the β integrin-positive cells of either the veliger stage larvae or the adult mussel tissues and the primary hemocyte cell culture. Despite the β integrin- and fibronectin-like proteins being expressed in different cell types of mussel larvae, we do not exclude the possibility of direct interaction between these two proteins during M. trossulus development or in adult tissues. PMID:26183371

  5. Epidermal growth factor-induced cyclooxygenase-2 enhances head and neck squamous cell carcinoma metastasis through fibronectin up-regulation

    PubMed Central

    Hsu, Jinn-Yuan; Chang, Kwang-Yu; Chen, Shang-Hung; Lee, Chung-Ta; Chang, Sheng-Tsung; Cheng, Hung-Chi; Chang, Wen-Chang; Chen, Ben-Kuen

    2015-01-01

    Epidermal growth factor receptor (EGFR) activation is a major cause of metastasis in many cancers, such as head and neck squamous cell carcinoma (HNSCC). However, whether the induction of cyclooxygenase-2 (COX-2) mediates EGF-enhanced HNSCC metastasis remains unclear. Interestingly, we found that EGF induced COX-2 expression mainly in HNSCC. The tumor cell transformation induced by EGF was repressed by COX-2 knockdown, and this repression was reversed by simultaneously treating the cells with EGF and prostaglandin E2 (PGE2). The down-regulation of COX-2 expression or inhibition of COX-2 activity significantly blocked EGF enhancement of cell migration and invasion, but the addition of PGE2 compensated for this inhibitory effect in COX-2-knockdown cells. COX-2 depletion inhibited EGF-induced matrix metalloproteinase (MMP)-1, MMP-2, MMP-3, MMP-9, and fibronectin expression and Rac1/cdc42 activation. The inhibitory effect of COX-2 depletion on MMPs and the fibronectin/Rac1/cdc42 axis were reversed by co-treatment with PGE2. Furthermore, depletion of fibronectin impeded the COX-2-enhanced binding of HNSCC cells to endothelial cells and tumor cells metastatic seeding of the lungs. These results demonstrate that EGF-induced COX-2 expression enhances HNSCC metastasis via activation of the fibronectin signaling pathway. The inhibition of COX-2 expression and activation may be a potential strategy for the treatment of EGFR-mediated HNSCC metastasis. PMID:25595899

  6. Fibronectin Modulates Cell Adhesion and Signaling to Promote Single Cell Migration of Highly Invasive Oral Squamous Cell Carcinoma

    PubMed Central

    Ramos, Grasieli de Oliveira; Bernardi, Lisiane; Lauxen, Isabel; Sant’Ana Filho, Manoel; Horwitz, Alan Rick; Lamers, Marcelo Lazzaron

    2016-01-01

    Cell migration is regulated by adhesion to the extracellular matrix (ECM) through integrins and activation of small RhoGTPases, such as RhoA and Rac1, resulting in changes to actomyosin organization. During invasion, epithelial-derived tumor cells switch from laminin-enriched basal membrane to collagen and fibronectin-enriched connective tissue. How this switch affects the tumor migration is still unclear. We tested the hypothesis that ECM dictates the invasiveness of Oral Squamous Cell Carcinoma (OSCC). We analyzed the migratory properties of two OSCC lines, a low invasive cell line with high e-cadherin levels (Linv/HE-cad) or a highly invasive cell line with low e-cadherin levels (Hinv/LE-cad), plated on different ECM components. Compared to laminin, fibronectin induced non-directional collective migration and decreased RhoA activity in Linv/HE-cad OSCC. For Hinv/LE-cad OSCC, fibronectin increased Rac1 activity and induced smaller adhesions, resulting in a fast single cell migration in both 2D and 3D environments. Consistent with these observations, human OSCC biopsies exhibited similar changes in cell-ECM adhesion distribution at the invasive front of the tumor, where cells encounter fibronectin. Our results indicate that ECM composition might induce a switch from collective to single cell migration according to tumor invasiveness due to changes in cell-ECM adhesion and the resulting signaling pathways that alter actomyosin organization. PMID:26978651

  7. Teal Amber Visible Focal Plane Technology

    NASA Astrophysics Data System (ADS)

    Johnson, Charles R.; Burczewski, Ron

    1981-12-01

    Deep-space surveillance missions have imposed severe demands on existing technology and simulated the search for new, advanced technology developments to provide higher performance. Defense Advanced Research Projects Agency (DARPA) sponsored Teal Amber as a visible charge-coupled device (CCD) and associated focal plane signal processing technology development and demonstration program. This paper describes this large-scale, staring-array-sensor concept. The current state of art in the resulting visibled CCD imagers is specified, along with the focal plane signal processor implementation in low power-weight-volume large-scale integrated (LSI) circuitry. Performance requirements and analytic predictions are compared to demonstration system results from an electro-optical test site in White Sands, New Mexico.

  8. Dynamic reactive astrocytes after focal ischemia

    PubMed Central

    Ding, Shinghua

    2014-01-01

    Astrocytes are specialized and most numerous glial cell type in the central nervous system and play important roles in physiology. Astrocytes are also critically involved in many neural disorders including focal ischemic stroke, a leading cause of brain injury and human death. One of the prominent pathological features of focal ischemic stroke is reactive astrogliosis and glial scar formation associated with morphological changes and proliferation. This review paper discusses the recent advances in spatial and temporal dynamics of morphology and proliferation of reactive astrocytes after ischemic stroke based on results from experimental animal studies. As reactive astrocytes exhibit stem cell-like properties, knowledge of dynamics of reactive astrocytes and glial scar formation will provide important insights for astrocyte-based cell therapy in stroke. PMID:25657720

  9. Myxoid adrenal adenoma with focal pseudoglandular pattern.

    PubMed

    De Padua, Michelle; Rajagopal, V

    2008-05-01

    Adrenal cortical tumors with myxoid change are rare tumors. To our knowledge, only 22 cases have been described so far in literature, which include 13 carcinomas and 9 adenomas. A pseudoglandular pattern has been described in 9 of these tumors. We report a case of a myxoid adenoma of the left adrenal gland in a 67-year-old woman, with a focal pseudoglandular pattern involving about 20% of the studied tumor. Rest of the tumor was composed of anastomosing cords of tumor cells. Abundant myxoid stroma was present, which stained positively with alcian blue and was weakly focally positive with periodic acid Schiff. Immunophenotype was consistent with an adrenal tumor, i.e., positive for vimentin, inhibin, and melan A. Cytokeratin AE1/AE3 and chromogranin were negative. MIB-1 index was < 0.1%. PMID:18579979

  10. Chest pain in focal musculoskeletal disorders.

    PubMed

    Stochkendahl, Mette Jensen; Christensen, Henrik Wulff

    2010-03-01

    The musculoskeletal system is a recognized source of chest pain. However, despite the apparently benign origin, patients with musculoskeletal chest pain remain under-diagnosed, untreated, and potentially continuously disabled in terms of anxiety, depression, and activities of daily living. Several overlapping conditions and syndromes of focal disorders, including Tietze syndrome, costochondritis, chest wall syndrome, muscle tenderness, slipping rib, cervical angina, and segmental dysfunction of the cervical and thoracic spine, have been reported to cause pain. For most of these syndromes, evidence arises mainly from case stories and empiric knowledge. For segmental dysfunction, clinical features of musculoskeletal chest pain have been characterized in a few clinical trials. This article summarizes the most commonly encountered syndromes of focal musculoskeletal disorders in clinical practice. PMID:20380955

  11. Focal tracer uptake in the jaw.

    PubMed

    El-Zahry, Mai R; Sinzinger, Helmut

    2014-01-01

    Focal tracer uptake in the jaw during conventional bone scintigraphy is a quite frequent finding usually due to dental disease and seldom to other diseases including malignant disease. Methylene diphosphonate-technetium-99m ((99m)Tc-MDP) 3-phase bone scan is considered the most sensitive imaging method for the detection of jaw osteonecrosis at an early stage. This finding can also but seldom be seen in patients undergoing palliative radionuclide treatment for bone metastases. In conclusion, focal jaw lesions are usually benign and of dental origin. In a small percentage of cancer patients of about 4.3%, jaw lesions as diagnosed among 347 cases of various carcinomas may be due to malignancy. Unfortunately, the number of studies is small, most of them are retrospective and few show biopsy results. PMID:25397621

  12. Focal region fields of distorted reflectors

    NASA Technical Reports Server (NTRS)

    Buris, N. E.; Kauffman, J. F.

    1988-01-01

    The problem of the focal region fields scattered by an arbitrary surface reflector under uniform plane wave illumination is solved. The physical optics (PO) approximation is used to calculate the current induced on the reflector. The surface of the reflector is described by a number of triangular domain-wise 5th degree bivariate polynomials. A 2-dimensional Gaussian quadrature is employed to numerically evaluate the integral expressions of the scattered fields. No Freshnel or Fraunhofer zone approximations are made. The relation of the focal fields problem to surface compensation techniques and other applications are mentioned. Several examples of distorted parabolic reflectors are presented. The computer code developed is included, together with instructions on its usage.

  13. Extensive Focal Epithelial Hyperplasia: A Case Report

    PubMed Central

    Mansouri, Zahra; Bakhtiari, Sedigheh; Noormohamadi, Robab

    2015-01-01

    Focal epithelial hyperplasia (FEH) or Heck’s disease is a rare viral infection of the oral mucosa caused by human papilloma virus especially subtypes 13 or 32. The frequency of this disease varies widely from one geographic region and ethnic groups to another. This paper reports an Iranian case of extensive focal epithelial hyperplasia. A 35-year-old man with FEH is described, in whom the lesions had persisted for more than 25 years. The lesion was diagnosed according to both clinical and histopathological features. Dental practitioner should be aware of these types of lesions and histopathological examination together and a careful clinical observation should be carried out for a definitive diagnosis. PMID:26351501

  14. Focal colors are universal after all

    PubMed Central

    Regier, Terry; Kay, Paul; Cook, Richard S.

    2005-01-01

    It is widely held that named color categories in the world's languages are organized around universal focal colors and that these focal colors tend to be chosen as the best examples of color terms across languages. However, this notion has been supported primarily by data from languages of industrialized societies. In contrast, recent research on a language from a nonindustrialized society has called this idea into question. We examine color-naming data from languages of 110 nonindustrialized societies and show that (i) best-example choices for color terms in these languages cluster near the prototypes for English white, black, red, green, yellow, and blue, and (ii) best-example choices cluster more tightly across languages than do the centers of category extensions, suggesting that universal best examples (foci) may be the source of universal tendencies in color naming. PMID:15923257

  15. Electric versus hydraulic drives

    SciTech Connect

    Not Available

    1983-01-01

    This volume records the proceedings of a conference organised by the Engineering Manufacturing Industries Division of the Institution of Mechanical Engineers. Topics considered include high performance position control - a review of the current state of developments; hydrostatic drives - present and future; electric drives - present and future trends; electrical and hydraulic drives for heavy industrial robots; the development of an electro-mechanical tilt system for the advanced passenger train; industrial hydraulic ring mains - effective or efficient. the comparison of performance of servo feed-drive systems; overhead crane drives; the future of d.c. servodrives; the choice of actuator for military systems; linear electro-hydraulic actuators; and actuation for industrial robots.

  16. Heparin binding by fibronectin module III-13 involves six discontinuous basic residues brought together to form a cationic cradle.

    PubMed

    Busby, T F; Argraves, W S; Brew, S A; Pechik, I; Gilliland, G L; Ingham, K C

    1995-08-01

    The thirteenth type III domain of fibronectin binds heparin almost as well as fibronectin itself and contains a so-called heparin-binding consensus sequence, Arg6-Arg7-Ala8-Arg9 (residues 1697-1700 in plasma fibronectin). Barkalow and Schwarzbauer (Barkalow, F.J., and Schwarzbauer, J.E. (1991) J. Biol. Chem. 266, 7812-7818) showed that mutation of Arg6-Arg7 in domain III-13 of recombinant truncated fibronectins abolished their ability to bind heparin-Sepharose. However, synthetic peptides containing this sequence have negligible affinity for heparin (Ingham, K.C., Brew, S.A., Migliorini, M. M., and Busby, T.F. (1993) Biochemistry 32, 12548-12553). We generated a three-dimensional model of fibronectin type III-13 based on the structure of a homologous domain from tenascin. The model places Arg23, Lys25, and Arg54 parallel to and in close proximity to the Arg6-Arg7-Ala8-Arg9 motif, suggesting that these residues may also contribute to the heparin-binding site. Domain III-13 and six single-site mutants containing Ser in place of each of the above-mentioned basic residues were expressed in Escherichia coli. All of the purified mutant domains melted reversibly with a Tm near that of the wild type indicating that they were correctly folded. When fluorescein-labeled heparin was titrated at physiological ionic strength, the wild type domain increased the anisotropy in a hyperbolic fashion with a Kd of 5-7 microM, close to that of the natural domain obtained by proteolysis of fibronectin. The R54S mutant bound 3-fold weaker and the remaining mutants bound at least 10-fold weaker than wild type. The results point out that the Arg6-Arg7-Ala8-Arg9 consensus sequence by itself has little affinity for heparin under physiological conditions, even when presented in the context of a folded domain. Thus, the heparin-binding site in fibronectin is more complex than previously realized. It is formed by a cluster of 6 positively charged residues that are remote in the sequence but

  17. Infrared fiber optic focal plane dispersers

    NASA Technical Reports Server (NTRS)

    Goebel, J. H.

    1981-01-01

    Far infrared transmissive fiber optics as a component in the design of integrated far infrared focal plane array utilization is discussed. A tightly packed bundle of fibers is placed at the focal plane, where an array of infrared detectors would normally reside, and then fanned out in two or three dimensions to individual detectors. Subsequently, the detectors are multiplexed by cryogenic electronics for relay of the data. A second possible application is frequency up-conversion (v sub 1 + v sub 2 = v sub 3), which takes advantage of the nonlinear optical index of refraction of certain infrared transmissive materials in fiber form. Again, a fiber bundle is utilized as above, but now a laser of frequency v sub 1 is mixed with the incoming radiation of frequency v sub 1 within the nonlinear fiber material. The sum, v sub 2 is then detected by near infrared or visible detectors which are more sensitive than those available at v sub 2. Due to the geometrical size limitations of detectors such as photomultipliers, the focal plane dispersal technique is advantageous for imaging up-conversion.

  18. Focal plane scanner with reciprocating spatial window

    NASA Technical Reports Server (NTRS)

    Mao, Chengye (Inventor)

    2000-01-01

    A focal plane scanner having a front objective lens, a spatial window for selectively passing a portion of the image therethrough, and a CCD array for receiving the passed portion of the image. All embodiments have a common feature whereby the spatial window and CCD array are mounted for simultaneous relative reciprocating movement with respect to the front objective lens, and the spatial window is mounted within the focal plane of the front objective. In a first embodiment, the spatial window is a slit and the CCD array is one-dimensional, and successive rows of the image in the focal plane of the front objective lens are passed to the CCD array by an image relay lens interposed between the slit and the CCD array. In a second embodiment, the spatial window is a slit, the CCD array is two-dimensional, and a prism-grating-prism optical spectrometer is interposed between the slit and the CCD array so as to cause the scanned row to be split into a plurality of spectral separations onto the CCD array. In a third embodiment, the CCD array is two-dimensional and the spatial window is a rectangular linear variable filter (LVF) window, so as to cause the scanned rows impinging on the LVF to be bandpass filtered into spectral components onto the CCD array through an image relay lens interposed between the LVF and the CCD array.

  19. [Focal therapy for prostate cancer: German version].

    PubMed

    Kasivisvanathan, V; Shah, T T; Donaldson, I; Kanthabalan, A; Moore, C M; Emberton, M; Ahmed, H U

    2015-02-01

    Focal therapy is a treatment strategy for men with localized prostate cancer that may serve as an alternative option to radical therapy. A number of minimally invasive ablative technologies are available to deliver treatment, and the energies most commonly used include high-intensity focused ultrasound and cryotherapy. The benefit of a tissue-preserving approach is the limitation of damage to key structures such as the neurovascular bundles, external urinary sphincter, rectal mucosa and bladder neck. This in turn minimizes side effects typically associated with radical therapies whilst also aiming to maintain oncological control. Over 30 single-centre studies of focal therapy have been published to date reporting excellent continence rates, good potency rates and acceptable short-term oncological outcomes. However, there are a number of controversial aspects associated with focal therapy including the index lesion hypothesis, patient selection criteria, assessment of treatment effect and the lack of medium- and long-term oncological outcomes. In the process of the adoption of new technology, there is a limited window of opportunity to provide this evidence in well-designed prospective trials. Men should be allowed to benefit from the potential advantages of this novel treatment whilst under close surveillance. An English version of this article is available under dx.doi.org/10.1007/s00120-014-3734-7. PMID:25690574

  20. Mechanism of Focal Adhesion Kinase Mechanosensing.

    PubMed

    Zhou, Jing; Aponte-Santamaría, Camilo; Sturm, Sebastian; Bullerjahn, Jakob Tómas; Bronowska, Agnieszka; Gräter, Frauke

    2015-11-01

    Mechanosensing at focal adhesions regulates vital cellular processes. Here, we present results from molecular dynamics (MD) and mechano-biochemical network simulations that suggest a direct role of Focal Adhesion Kinase (FAK) as a mechano-sensor. Tensile forces, propagating from the membrane through the PIP2 binding site of the FERM domain and from the cytoskeleton-anchored FAT domain, activate FAK by unlocking its central phosphorylation site (Tyr576/577) from the autoinhibitory FERM domain. Varying loading rates, pulling directions, and membrane PIP2 concentrations corroborate the specific opening of the FERM-kinase domain interface, due to its remarkably lower mechanical stability compared to the individual alpha-helical domains and the PIP2-FERM link. Analyzing downstream signaling networks provides further evidence for an intrinsic mechano-signaling role of FAK in broadcasting force signals through Ras to the nucleus. This distinguishes FAK from hitherto identified focal adhesion mechano-responsive molecules, allowing a new interpretation of cell stretching experiments. PMID:26544178

  1. The Focal Surface of EUSO Telescope

    NASA Technical Reports Server (NTRS)

    Shimizu, H. M.; Kawasaki, Y.; Takizawa, Y.; Sakaki, N.; Teshima, M.; Ebisuzaki, T.; Takahashi, Y.; Adams, J.; Catalano, O.; Scarisi, L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    The Extreme Universe Space Observatory (EUSO) is a science mission under conceptual design for the detection of extremely high energy cosmic rays and neutrinos by the observation of time-resolved images of atmospheric fluorescence photons generated along the extensive air shower, in the near ultraviolet wavelength region. A refractive telescope with double-sided double Fresnel lens will be employed to achieve a large field of view of 60 degrees. The energy and arrival direction of the primary particles will be determined by observing the time evolution of the airshower. The focal surface of the EUSO telescope will be segmented to a few hundred thousand pixels to resolve the entire field of view with the angular resolution of the order of 0.1 degree. The time evolution will be observed with the time resolution of 0.8 microsecond. A large scale array of multianode photomultiplier (MAPMT) is being studied as the EUSO focal surface. The MAPMT array is capable of detecting near ultraviolet photons at single photoelectron level. In this contribution, we will report the present status of the focal surface design including the optimization of anode segmentation and the minimization of the dead area and discuss overall experimental performance in detecting extensive airshowers.

  2. Mechanism of Focal Adhesion Kinase Mechanosensing

    PubMed Central

    Sturm, Sebastian; Bullerjahn, Jakob Tómas; Bronowska, Agnieszka; Gräter, Frauke

    2015-01-01

    Mechanosensing at focal adhesions regulates vital cellular processes. Here, we present results from molecular dynamics (MD) and mechano-biochemical network simulations that suggest a direct role of Focal Adhesion Kinase (FAK) as a mechano-sensor. Tensile forces, propagating from the membrane through the PIP2 binding site of the FERM domain and from the cytoskeleton-anchored FAT domain, activate FAK by unlocking its central phosphorylation site (Tyr576/577) from the autoinhibitory FERM domain. Varying loading rates, pulling directions, and membrane PIP2 concentrations corroborate the specific opening of the FERM-kinase domain interface, due to its remarkably lower mechanical stability compared to the individual alpha-helical domains and the PIP2-FERM link. Analyzing downstream signaling networks provides further evidence for an intrinsic mechano-signaling role of FAK in broadcasting force signals through Ras to the nucleus. This distinguishes FAK from hitherto identified focal adhesion mechano-responsive molecules, allowing a new interpretation of cell stretching experiments. PMID:26544178

  3. Multispectral linear array (MLA) focal plane mechanical and thermal design

    NASA Technical Reports Server (NTRS)

    Mitchell, A. S.; Kaminski, E. F.

    1982-01-01

    The mechanical and thermal design of an integrated focal plane subsystem of a Multispectral Linear Array (MLA) instrument is discussed in terms of focal-plane alignment, thermoelastic performance, and thermal requirements. The modular construction and thermal control of the focal plane array are discussed.

  4. Focus in Grade 1: Teaching with Curriculum Focal Points

    ERIC Educational Resources Information Center

    Fuson, Karen; Clements, Douglas; Beckmann, Sybilla

    2010-01-01

    "Focus in Grade 1: Teaching with Curriculum Focal Points" describes and illustrates learning paths for the mathematical concepts and skills of each grade 1 Focal Point as presented in Curriculum Focal Points for Prekindergarten through Grade 8 Mathematics. It includes representational supports for teaching and learning that can facilitate…

  5. Focus in Grade 2: Teaching with Curriculum Focal Points

    ERIC Educational Resources Information Center

    National Council of Teachers of Mathematics, 2011

    2011-01-01

    "Focus in Grade 2: Teaching with Curriculum Focal Points" describes and illustrates learning paths for the mathematical concepts and skills of each grade 2 Focal Point as presented in 'Curriculum Focal Points for Prekindergarten through Grade 8 Mathematics". It includes representational supports for teaching and learning that can facilitate…

  6. Drill drive mechanism

    DOEpatents

    Dressel, Michael O.

    1979-01-01

    A drill drive mechanism is especially adapted to provide both rotational drive and axial feed for a drill of substantial diameter such as may be used for drilling holes for roof bolts in mine shafts. The drill shaft is made with a helical pattern of scroll-like projections on its surface for removal of cuttings. The drill drive mechanism includes a plurality of sprockets carrying two chains of drive links which are arranged to interlock around the drill shaft with each drive link having depressions which mate with the scroll-like projections. As the chain links move upwardly or downwardly the surfaces of the depressions in the links mate with the scroll projections to move the shaft axially. Tangs on the drive links mate with notch surfaces between scroll projections to provide a means for rotating the shaft. Projections on the drive links mate together at the center to hold the drive links tightly around the drill shaft. The entire chain drive mechanism is rotated around the drill shaft axis by means of a hydraulic motor and gear drive to cause rotation of the drill shaft. This gear drive also connects with a differential gearset which is interconnected with a second gear. A second motor is connected to the spider shaft of the differential gearset to produce differential movement (speeds) at the output gears of the differential gearset. This differential in speed is utilized to drive said second gear at a speed different from the speed of said gear drive, this speed differential being utilized to drive said sprockets for axial movement of said drill shaft.

  7. Focal Points, Endogenous Processes, and Exogenous Shocks in the Autism Epidemic

    PubMed Central

    Liu, Kayuet; Bearman, Peter S.

    2014-01-01

    Autism prevalence has increased rapidly in the United States during the past two decades. We have previously shown that the diffusion of information about autism through spatially proximate social relations has contributed significantly to the epidemic. This study expands on this finding by identifying the focal points for interaction that drive the proximity effect on subsequent diagnoses. We then consider how diffusion dynamics through interaction at critical focal points, in tandem with exogenous shocks, could have shaped the spatial dynamics of autism in California. We achieve these goals through an empirically calibrated simulation model of the whole population of 3- to 9-year-olds in California. We show that in the absence of interaction at these foci—principally malls and schools—we would not observe an autism epidemic. We also explore the idea that epigenetic changes affecting one generation in the distal past could shape the precise spatial patterns we observe among the next generation. PMID:26166907

  8. Heparin-induced conformational changes of fibronectin within the extracellular matrix promote hMSC osteogenic differentiation.

    PubMed

    Li, Bojun; Lin, Zhe; Mitsi, Maria; Zhang, Yang; Vogel, Viola

    2015-01-01

    An increasing body of evidence suggests important roles of extracellular matrix (ECM) in regulating stem cell fate. This knowledge can be exploited in tissue engineering applications for the design of ECM scaffolds appropriate to direct stem cell differentiation. By probing the conformation of fibronectin (Fn) using fluorescence resonance energy transfer (FRET), we show here that heparin treatment of the fibroblast-derived ECM scaffolds resulted in more extended conformations of fibrillar Fn in ECM. Since heparin is a highly negatively charged molecule while fibronectin contains segments of positively charged modules, including FnIII13, electrostatic interactions between Fn and heparin might interfere with residual quaternary structure in relaxed fibronectin fibers thereby opening up buried sites. The conformation of modules FnIII12-14 in particular, which contain one of the heparin binding sites as well as binding sites for many growth factors, may be activated by heparin, resulting in alterations in growth factor binding to Fn. Indeed, upregulated osteogenic differentiation was observed when hMSCs were seeded on ECM scaffolds that had been treated with heparin and were subsequently chemically fixed. In contrast, either rigidifying relaxed fibers by fixation alone, or heparin treatment without fixation had no effect. We hypothesize that fibronectin's conformations within the ECM are activated by heparin such as to coordinate with other factors to upregulate hMSC osteogenic differentiation. Thus, the conformational changes of fibronectin within the ECM could serve as a 'converter' to tune hMSC differentiation in extracellular matrices. This knowledge could also be exploited to promote osteogenic stem cell differentiation on biomedical surfaces. PMID:26214191

  9. Fibroblast invasive migration into fibronectin/fibrin gels requires a previously uncharacterized dermatan sulfate-CD44 proteoglycan.

    PubMed

    Clark, Richard A F; Lin, Fubao; Greiling, Doris; An, Jianqang; Couchman, John R

    2004-02-01

    After tissue injury, fibroblast migration from the peri-wound collagenous stroma into the fibrin-laden wound is critical for granulation tissue formation and subsequent healing. Recently we found that fibroblast transmigration from a collagen matrix into a fibrin matrix required the presence of fibronectin. Several integrins-alpha 4 beta 1, alpha 5 beta 1, and alpha v beta 3-with known fibronectin binding affinity were necessary for this invasive migration. Here we examined another family of cell surface receptors: the proteoglycans. We found that dermatan sulfate was required for fibroblast migration into a fibronectin/fibrin gel. This conclusion was based on beta-xyloside inhibition of glycanation and specific glycosaminoglycan degradation. CD44, a cell surface receptor known to bind hyaluronan, not infrequently exists as a proteoglycan, decorated with various glycosaminoglycan chains including heparan sulfate and chondroitin sulfate, and as such can bind fibronectin. We found that CD44H, the non-spliced isoform of CD44, was necessary for fibroblast invasion into fibronectin/fibrin gels. Resting fibroblasts expressed mostly nonglycanated CD44H core protein, which became glycanated with chondroitin sulfate and dermatan sulfate, but not heparan sulfate, after a 24 h incubation with platelet-derived growth factor, the stimulus used in the migration assay. These results demonstrate that dermatan sulfate-CD44H proteoglycan is essential for fibroblast migration into fibrin clots and that platelet-derived growth factor, the stimulus for migration, induces the production of chondroitin-sulfate- and dermatan-sulfate-glycanated CD44H. PMID:15009704

  10. Construction and Myogenic Differentiation of 3D Myoblast Tissues Fabricated by Fibronectin-Gelatin Nanofilm Coating

    PubMed Central

    Gribova, Varvara; Liu, Chen Yun; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-01-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ~ 76 µm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  11. Fibronectin immobilization on to robotic-dispensed nanobioactive glass/polycaprolactone scaffolds for bone tissue engineering.

    PubMed

    Won, Jong-Eun; Mateos-Timoneda, Miguel A; Castano, Oscar; Planell, Josep A; Seo, Seog-Jin; Lee, Eun-Jung; Han, Cheol-Min; Kim, Hae-Won

    2015-04-01

    Bioactive nanocomposite scaffolds with cell-adhesive surface have excellent bone regeneration capacities. Fibronectin (FN)-immobilized nanobioactive glass (nBG)/polycaprolactone (PCL) (FN-nBG/PCL) scaffolds with an open pore architecture were generated by a robotic-dispensing technique. The surface immobilization level of FN was significantly higher on the nBG/PCL scaffolds than on the PCL scaffolds, mainly due to the incorporated nBG that provided hydrophilic chemical-linking sites. FN-nBG/PCL scaffolds significantly improved cell responses, including initial anchorage and subsequent cell proliferation. Although further in-depth studies on cell differentiation and the in vivo animal responses are required, bioactive nanocomposite scaffolds with cell-favoring surface are considered to provide promising three-dimensional substrate for bone regeneration. PMID:25502922

  12. A novel bipartite splicing enhancer modulates the differential processing of the human fibronectin EDA exon.

    PubMed Central

    Caputi, M; Casari, G; Guenzi, S; Tagliabue, R; Sidoli, A; Melo, C A; Baralle, F E

    1994-01-01

    EDA is a facultative type III homology of human fibronectin encoded by an alternative spliced exon. The EDA+ and EDA- mRNA forms show a cell type specific distribution with their relative proportion varying during development, aging and oncogenic transformation. We have previously demonstrated that an 81 bp nucleotide sequence within the exon itself is essential for differential RNA processing. Fine mapping of cis acting elements within this region has been carried out to identify possible target sites for the modulation of alternative splicing. There are at least two short nucleotide sequences involved. Element A (GAAGAAGA) is a positive modulator for the recognition of the exon, its deletion results in constitutive exclusion of the EDA exon. Element B (CAAGG) is a negative modulator for exon recognition, its deletion results in constitutive inclusion of the EDA exon. This bipartite structure of the splicing enhancer is a novel feature of the mammalian exons. Images PMID:8152907

  13. Integrin-fibronectin interactions at the cell-material interface: initial integrin binding and signaling.

    PubMed

    García, A J; Boettiger, D

    1999-12-01

    Integrin receptors mediate cell adhesion to extracellular matrices and provide signals that direct proliferation and differentiation. Integrin binding involves receptor-ligand interactions at the cell-substrate interface and assembly and reorganization of structural and signaling elements at the cytoplasmic face. Using a cross-linking/extraction/reversal method to quantify bound integrins, we demonstrate that the density of alpha5beta1 integrin-fibronectin bonds increases linearly with ligand density, as predicted by simple receptor-ligand equilibrium. This linear relationship is consistent with linear increases in cell adhesion strength with receptor and ligand surface densities. Furthermore, we show that phosphorylation of FAK, a tyrosine kinase involved in early integrin-mediated signaling, increases linearly with the number of integrin-Fn bonds. These linear relationships suggest the absence of cooperative effects in the initial stages of mechanical coupling and adhesion-mediated signaling. PMID:10614947

  14. Construction and myogenic differentiation of 3D myoblast tissues fabricated by fibronectin-gelatin nanofilm coating.

    PubMed

    Gribova, Varvara; Liu, Chun-Yen; Nishiguchi, Akihiro; Matsusaki, Michiya; Boudou, Thomas; Picart, Catherine; Akashi, Mitsuru

    2016-06-01

    In this study, we used a recently developed approach of coating the cells with fibronectin-gelatin nanofilms to build 3D skeletal muscle tissue models. We constructed the microtissues from C2C12 myoblasts and subsequently differentiated them to form muscle-like tissue. The thickness of the constructs could be successfully controlled by altering the number of seeded cells. We were able to build up to ∼76 μm thick 3D constructs that formed multinucleated myotubes. We also found that Rho-kinase inhibitor Y27632 improved myotube formation in thick constructs. Our approach makes it possible to rapidly form 3D muscle tissues and is promising for the in vitro construction of physiologically relevant human skeletal muscle tissue models. PMID:27125461

  15. The effect of fibronectin on structural and biological properties of single walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Mottaghitalab, Fatemeh; Farokhi, Mehdi; Atyabi, Fatemeh; Omidvar, Ramin; Shokrgozar, Mohammad Ali; Sadeghizadeh, Majid

    2015-06-01

    Despite the attractive properties of carbon nanotubes (CNTs), cytoxicity and hydrophobicity are two main considerable features which limit their application in biomedical fields. It was well established that treating CNTs with extracellular matrix components could reduce these unfavourable characteristics. In an attempt to address these issues, fibronectin (FN) with different concentrations was loaded on single walled carbon nanotubes (SWCNTs) substrate. Scanning electron microscope, atomic force microscopy (AFM), contact angles and X-ray photoelectron spectroscopy (XPS) were preformed in order to characterize FN loaded SWCNTs substrates. According to XPS and AFM results, FN could interact with SWCNTs and for this, the hydrophilicity of SWCNTs was improved. Additionally, SWCNT modified with FN showed less cytotoxicity compared with neat SWCNT. Finally, FN was shown to act as an interesting extracellular component for enhancing the biological properties of SWCNT.

  16. Enhanced cell growth by nanoengineering zirconia to stimulate electrostatic fibronectin activation

    NASA Astrophysics Data System (ADS)

    Rubinstein, A. I.; Sabirianov, R. F.; Namavar, F.

    2014-02-01

    We address the enhanced bone growth on designed nanocrystalline zirconia implants as reported by in vivo experiments. In vitro experiments demonstrate that the activation of adhesive proteins on nanoengineered zirconia stimulates cell adhesion and growth as shown by confocal microscopy. Fibrillar fibronectin (FN) forms a matrix assembly on the nanostructured surface in the cell adhesion process. We discuss the importance of FN dimer activation due to its immobilization on the designed nanocrystalline ZrO2 implant fabricated by ion beam assisted deposition. The Monte-Carlo analysis indicates that FN activation on the surface can be promoted by selective electrostatic interactions between negatively charged ZrO2 surface patches and oppositely charged FN domains.

  17. Chemical shift assignments of the fibronectin III like domains 7-8 of type VII collagen.

    PubMed

    Hermsdorf, Ulrike; Seeger, Karsten

    2016-04-01

    Type VII collagen (Col7) is important for skin stability. This is underlined by the severe skin blistering phenotype in the Col7 related diseases dystrophic epidermolysis bullosa and epidermolysis bullosa acquisita (EBA). Col7 has a large N-terminal non-collagenous domain (NC1) that is followed by the triple helical collagenous domain. The NC1 domain has subdomains with homology to adhesion molecules and mediates important interactions within the extracellular matrix. An 185 amino acid long part of the NC1-subdomain termed fibronectin III like domains 7 and 8 (FNIII7-8) was investigated. Antibodies against this region are pathogenic in a mouse model of EBA and one reported missense mutations of Col7 lies within these domains. The nearly complete NMR resonance assignment of recombinant FNIII7-8 of Col7 is reported. PMID:26364055

  18. Fibers with Integrated Mechanochemical Switches: Minimalistic Design Principles Derived from Fibronectin

    PubMed Central

    Peleg, Orit; Savin, Thierry; Kolmakov, German V.; Salib, Isaac G.; Balazs, Anna C.; Kröger, Martin; Vogel, Viola

    2012-01-01

    Inspired by molecular mechanisms that cells exploit to sense mechanical forces and convert them into biochemical signals, chemists dream of designing mechanochemical switches integrated into materials. Using the adhesion protein fibronectin, whose multiple repeats essentially display distinct molecular recognition motifs, we derived a computational model to explain how minimalistic designs of repeats translate into the mechanical characteristics of their fibrillar assemblies. The hierarchy of repeat-unfolding within fibrils is controlled not only by their relative mechanical stabilities, as found for single molecules, but also by the strength of cryptic interactions between adjacent molecules that become activated by stretching. The force-induced exposure of cryptic sites furthermore regulates the nonlinearity of stress-strain curves, the strain at which such fibers break, and the refolding kinetics and fraction of misfolded repeats. Gaining such computational insights at the mesoscale is important because translating protein-based concepts into novel polymer designs has proven difficult. PMID:23199919

  19. Fibronectin and other DIC-related variables in septic ICU patients receiving cryoprecipitate.

    PubMed

    Hesselvik, F; Brodin, B; Blombäck, M; Cedergren, B; Lieden, G; Maller, R

    1985-01-01

    In a controlled study of fibronectin supplementation in sepsis, 11 ICU patients in septic shock were scheduled to receive either cryoprecipitate from 20-40 donors (n = 6) or 250-300 ml of stored plasma (n = 5) (two infusions over 24 h). We wanted to: compare some "conventional" DIC variables in the ICU (platelet count, prothrombin complex = NT, FDP) to additional variables: Fibronectin (Fn), fibrinogen (Fg), F V, FVIII R:Ag, F VIII:C activity, F XII, plasminogen (Plg), antiplasmin (AP), antithrombin (AT), kallikrein inhibiting activity (KI) and spontaneous proteolytic activity (SPA): study the effects of cryoprecipitate or plasma infusion on three variables. Samples were taken before the first infusion, and 24 and 48 h after. At onset, high levels (p less than .001 when compared to blood donors) of Fg, VIIIR:Ag and VIII:C were seen. KI levels were within the normal range. F V was low (p less than .05). Fn, NT, XII, Plg, AP and AT were markedly low (p less than .001). SPA showed great variation. When compared to 28 patients with severe infections, but not in septic shock, the ICU group had higher VIIIR:Ag (p less than .05) and VIII:C (p less than .01), and lower XII, Plg, AP and AT (p less than .001). FDP was elevated in all ICU patients. Five patients were thrombocytopenic, and in these a pattern with low levels of Plg and AT was observed. Fn did not correlate well to the other variables measured. These results indicate a marked activation of coagulation and fibrinolysis in these severely ill patients.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3937220

  20. The Structure of Irisin Reveals a Novel Intersubunit β-Sheet Fibronectin Type III (FNIII) Dimer

    PubMed Central

    Schumacher, Maria A.; Chinnam, Nagababu; Ohashi, Tomoo; Shah, Riddhi Sanjay; Erickson, Harold P.

    2013-01-01

    Irisin was recently identified as a putative myokine that is induced by exercise. Studies suggest that it is produced by cleavage of the FNDC5 (fibronectin domain-containing protein 5) receptor; irisin corresponds to the extracellular receptor ectodomain. Data suggesting that irisin stimulates white-to-brown fat conversion have led to the hypothesis that it does so by binding an unknown receptor, thus functioning as a myokine. As brown fat promotes energy dissipation, myokines that elicit the transformation of white to brown fat have potentially profound benefits in the treatment of obesity and metabolic disorders. Understanding the molecular basis for such exercise-induced phenomena is thus of considerable interest. Moreover, FNDC5-like receptors are highly conserved and have been shown to be critical for neuronal development. However, the structural and molecular mechanisms utilized by these proteins are currently unknown. Here, we describe the crystal structure and biochemical characterization of the FNDC5 ectodomain, corresponding to the irisin myokine. The 2.28 Å structure shows that irisin consists of an N-terminal fibronectin III (FNIII)-like domain attached to a flexible C-terminal tail. Strikingly, the FNIII-like domain forms a continuous intersubunit β-sheet dimer, previously unobserved for any FNIII protein. Biochemical data confirm that irisin is a dimer and that dimerization is unaffected by glycosylation. This finding suggests a possible mechanism for receptor activation by the irisin domain as a preformed myokine dimer ligand or as a paracrine or autocrine dimerization module on FNDC5-like receptors. PMID:24114836

  1. Fibronectin-Binding Protein of Borrelia hermsii Expressed in the Blood of Mice with Relapsing Fever

    PubMed Central

    Lewis, Eric R. G.; Marcsisin, Renee A.; Campeau Miller, Shelley A.; Hue, Fong; Phillips, April; AuCoin, David P.

    2014-01-01

    To identify and characterize surface proteins expressed by the relapsing fever (RF) agent Borrelia hermsii in the blood of infected mice, we used a cell-free filtrate of their blood to immunize congenic naive mice. The resultant antiserum was used for Western blotting of cell lysates, and gel slices corresponding to reactive bands were subjected to liquid chromatography-tandem mass spectrometry, followed by a search of the proteome database with the peptides. One of the immunogens was identified as the BHA007 protein, which is encoded by a 174-kb linear plasmid. BHA007 had sequence features of lipoproteins, was surface exposed by the criteria of in situ protease susceptibility and agglutination of Vtp− cells by anti-BHA007 antibodies, and was not essential for in vitro growth. BHA007 elicited antibodies during experimental infection of mice, but immunization with recombinant protein did not confer protection against needle-delivered infection. Open reading frames (ORFs) orthologous to BHA007 were found on large plasmids of other RF species, including the coding sequences for the CihC proteins of Borrelia duttonii and B. recurrentis, but not in Lyme disease Borrelia species. Recombinant BHA007 bound both human and bovine fibronectin with Kd (dissociation constant) values of 22 and 33 nM, respectively, and bound to C4-binding protein with less affinity. The distant homology of BHA007 and its orthologs to BBK32 proteins of Lyme disease species, as well as to previously described BBK32-like proteins in relapsing fever species, indicates that BHA007 is a member of a large family of multifunctional proteins in Borrelia species that bind to fibronectin as well as other host proteins. PMID:24686059

  2. Fibronectin- and Collagen-Mimetic Ligands Regulate BMSC Chondrogenesis in 3D Hydrogels

    PubMed Central

    Connelly, J.T.; Petrie, T.A.; García, A.J.; Levenston, M.E.

    2016-01-01

    Modification of tissue engineering scaffolds with bioactive molecules is a potential strategy for modulating cell behavior and guiding tissue regeneration. While adhesion to RGD peptides has been shown to inhibit in vitro chondrogenesis, the effects of extracellular matrix (ECM)-mimetic ligands with complex secondary and tertiary structures are unknown. This study aimed to determine whether collagen- and fibronectin-mimetic ligands would retain biologic functionality in three-dimensional (3D) hydrogels, whether different ECM-mimetic ligands differentially influence in vitro chondrogenesis, and if effects of ligands on differentiation depend on soluble biochemical stimuli. A linear RGD peptide, a recombinant fibronectin fragment containing the seven to 10 Type III repeats (FnIII7-10) and a triple helical, collagen mimetic peptide with the GFOGER motif were covalently coupled to agarose gels using the sulfo-SANPAH crosslinker, and bone marrow stromal cells (BMSCs) were cultured within the 3D hydrogels.. The ligands retained biologic functionality within the agarose gels and promoted density-dependent BMSC spreading. Interactions with all adhesive ligands inhibited stimulation by chondrogenic factors of collagen Type II and aggrecanmRNA levels and deposition of sulfated glycosaminoglycans. In medium containing fetal bovine serum, interactions with the GFOGER peptide enhanced mRNA expression of the osteogenic gene osteocalcin whereas FnIII7-10 inhibited osteocalcin expression. In conclusion, modification of agarose hydrogels with ECM-mimetic ligands can influence the differentiation of BMSCs in a manner that depends strongly on the presence and nature of soluble biochemical stimuli. PMID:21932193

  3. Fibronectin provides a conduit for fibroblast transmigration from collagenous stroma into fibrin clot provisional matrix.

    PubMed

    Greiling, D; Clark, R A

    1997-04-01

    After injury, the wound space is filled with a fibrin/fibronectin clot containing growth factors released by platelets and monocytes. In response to these factors, fibroblasts migrate into the fibrin clot and contribute to the formation of granulation tissue. The functional mechanisms allowing fibroblasts to leave the collagenous matrix of normal connective tissue and invade the provisional matrix of the fibrin clot have not been fully defined. To investigate these mechanisms we established a new in vitro model which simulates specific aspects of early wound healing, that is, the migration of fibroblasts from a three-dimensional collagen matrix into a fibrin clot. This transmigration could be induced by physiological concentrations of platelet releasate or platelet-derived growth factor BB (PDGF-BB) in a concentration-dependent manner. At 24 hours irradiated fibroblasts invaded the fibrin gel almost as well as non-irradiated cells, indicating that transmigration was independent of proliferation. Plasminogen and its activators appear to be necessary for invasion of the fibrin clot since protease inhibitors decreased the amount of migration. These serine proteases, however, were not necessary for exit from the collagen gel as fibroblasts migrated out of the collagen gel onto a surface coated with fibrin fibrils even in the presence of inhibitors. Removal of fibronectin (FN) from either the collagen gel or the fibrin gel markedly decreased the number of migrating cells, suggesting that FN provides a conduit for transmigration. Cell movement in the in vitro model was inhibited by RGD peptide, and by monoclonal antibodies against the subunits of the alpha5 beta1 and alpha v beta3 integrin receptor. Thus, the functional requirements for fibroblast transmigration from collagen-rich to fibrin-rich matrices, such as occurs in early wound healing, have been partially defined using an in vitro paradigm of this important biologic process. PMID:9133673

  4. Magnetostrictive roller drive motor

    NASA Astrophysics Data System (ADS)

    Vranish, John M.

    1992-01-01

    A magnetostrictive drive motor is disclosed which has a rotary drive shaft in the form of a drum which is encircled by a plurality of substantially equally spaced roller members in the form of two sets of cones which are in contact with the respective cam surfaces on the inside surface of an outer drive ring. The drive ring is attached to sets of opposing pairs of magnetostrictive rods. Each rod in a pair is mutually positioned end to end within respective energizing coils. When one of the coils in an opposing pair is energized, the energized rod expands while the other rod is caused to contract, causing the drive ring to rock, i.e., rotate slightly in either the clockwise or counterclockwise direction, depending upon which rod in a pair is energized. As the drive ring is activated in repetitive cycles in either direction, one set of drive cones attempts to roll up their respective cam surface but are pinned between the drive shaft drum and the drive ring. As the frictional force preventing sliding builds up, the cones become locked, setting up reaction forces including a tangential component which is imparted to the drive shaft drum to provide a source of motor torque. Simultaneously the other set of cones are disengaged from the drive shaft drum. Upon deactivation of the magnetostrictive rod coils, the force on the drive cones is released, causing the system to return to an initial rest position. By repetitively cycling the energization of the magnetostrictive rods, the drive shaft drum indexes in microradian rotational steps.

  5. Dynamic focal spots registration algorithm for freeform surface measurement

    NASA Astrophysics Data System (ADS)

    Guo, Wenjiang; Zhao, Liping; Chen, I.-Ming

    2013-06-01

    In a wavefront sensing system, the raw data for surface reconstruction, either the slope matrix or curvature matrix, is obtained through centroiding on the focal spot images. Centroiding is to calculate the first moment within a certain area of interest, which encloses the focal spot. As the distribution of focal spots is correlated to the surface sampling condition, while a uniform rectangular grid is good enough to register all the focal spots of a uniformly sampled near flat surface, the focal spots of aspherical or freeform surfaces have varying shapes and sizes depending on the surface geometry. In this case, the normal registration method is not applicable. This paper proposed a dynamic focal spots registration algorithm to automatically analyze the image, identify and register every focal spot for centroiding at one go. Through experiment on a freeform surface with polynomial coefficients up to 10th order, the feasibility and effectiveness of the proposed algorithm is proved.

  6. Superluminal warp drive

    NASA Astrophysics Data System (ADS)

    González-Díaz, Pedro F.

    2007-09-01

    In this Letter we consider a warp drive spacetime resulting from that suggested by Alcubierre when the spaceship can only travel faster than light. Restricting to the two dimensions that retains most of the physics, we derive the thermodynamic properties of the warp drive and show that the temperature of the spaceship rises up as its apparent velocity increases. We also find that the warp drive spacetime can be exhibited in a manifestly cosmological form.

  7. A kinetic model for RNA-interference of focal adhesions

    PubMed Central

    2013-01-01

    Background Focal adhesions are integrin-based cell-matrix contacts that transduce and integrate mechanical and biochemical cues from the environment. They develop from smaller and more numerous focal complexes under the influence of mechanical force and are key elements for many physiological and disease-related processes, including wound healing and metastasis. More than 150 different proteins localize to focal adhesions and have been systematically classified in the adhesome project (http://www.adhesome.org). First RNAi-screens have been performed for focal adhesions and the effect of knockdown of many of these components on the number, size, shape and location of focal adhesions has been reported. Results We have developed a kinetic model for RNA interference of focal adhesions which represents some of its main elements: a spatially layered structure, signaling through the small GTPases Rac and Rho, and maturation from focal complexes to focal adhesions under force. The response to force is described by two complementary scenarios corresponding to slip and catch bond behavior, respectively. Using estimated and literature values for the model parameters, three time scales of the dynamics of RNAi-influenced focal adhesions are identified: a sub-minute time scale for the assembly of focal complexes, a sub-hour time scale for the maturation to focal adhesions, and a time scale of days that controls the siRNA-mediated knockdown. Our model shows bistability between states dominated by focal complexes and focal adhesions, respectively. Catch bonding strongly extends the range of stability of the state dominated by focal adhesions. A sensitivity analysis predicts that knockdown of focal adhesion components is more efficient for focal adhesions with slip bonds or if the system is in a state dominated by focal complexes. Knockdown of Rho leads to an increase of focal complexes. Conclusions The suggested model provides a kinetic description of the effect of RNA

  8. Diabetes and driving.

    PubMed

    Inkster, B; Frier, B M

    2013-09-01

    The principal safety concern for driving for people treated with insulin or insulin secretagogues is hypoglycaemia, which impairs driving performance. Other complications, such as those causing visual impairment and peripheral neuropathy, are also relevant to medical fitness to drive. Case control studies have suggested that drivers with diabetes pose a modestly increased but acceptable and measurable risk of motor vehicle accidents compared to non-diabetic drivers, but many studies are limited and of poor quality. Factors which have been shown to increase driving risk include previous episodes of severe hypoglycaemia, previous hypoglycaemia while driving, strict glycaemic control (lower HbA1c) and absence of blood glucose monitoring before driving. Impaired awareness of hypoglycaemia may be counteracted by frequent blood glucose testing. The European Union Third directive on driving (2006) has necessitated changes in statutory regulations for driving licences for people with diabetes in all European States, including the UK. Stricter criteria have been introduced for Group 1 vehicle licences while those for Group 2 licences have been relaxed. Insulin-treated drivers can now apply to drive Group 2 vehicles, but in the UK must meet very strict criteria and be assessed by an independent specialist to be issued with a 1-year licence. PMID:23350766

  9. Efficacy of lacosamide by focal seizure subtype.

    PubMed

    Sperling, Michael R; Rosenow, Felix; Faught, Edward; Hebert, David; Doty, Pamela; Isojärvi, Jouko

    2014-10-01

    The purpose of this post hoc exploratory analysis was to determine the effects of the antiepileptic drug, lacosamide, on focal (partial-onset) seizure subtypes. Patient data from the three lacosamide pivotal trials were grouped and pooled by focal seizure subtype at Baseline: simple partial seizures (SPS), complex partial seizures (CPS), and secondarily generalized partial seizures (SGPS). Both efficacy outcomes (median percent change from Baseline to Maintenance Phase in seizure frequency per 28 days and the proportion of patients experiencing at least a 50% reduction in seizures) were evaluated by lacosamide dose (200, 400, or 600 mg/day) compared to placebo for each seizure subtype. An additional analysis was performed to determine whether a shift from more severe focal seizure subtypes to less severe occurred upon treatment with lacosamide. In patients with CPS or SGPS at Baseline, lacosamide 400 mg/day (maximum recommended daily dose) and 600 mg/day reduced the frequency of CPS and SGPS compared to placebo. Likewise, a proportion of patients with CPS and SGPS at Baseline experienced at least a 50% reduction in the frequency of CPS and SGPS (≥50% responder rate) in the lacosamide 400 and 600 mg/day groups compared with placebo. For both outcomes, numerically greatest responses were observed in the lacosamide 600 mg/day group among patients with SGPS at Baseline. In patients with SPS at Baseline, no difference between placebo and lacosamide was observed for either efficacy outcome. An additional exploratory analysis suggests that in patients with SPS at Baseline, CPS and SGPS may have been shifted to less severe SPS upon treatment with lacosamide. The results of these exploratory analyses revealed reductions in CPS and SGPS frequency with adjunctive lacosamide. Reduction in CPS and SGPS may confound assessment of SPS since the CPS or SGPS may possibly change to SPS by effective treatment. PMID:25082395

  10. Wave statistics in a coastal focal zone

    NASA Astrophysics Data System (ADS)

    Janssen, T. T.; Herbers, T. H. C.; Pearman, D. W.; Van Ettinger, E.; Smit, P. B.

    2014-12-01

    Wave-current dynamics in wave focal zones in exposed coastal inlets and river mouths are still poorly understood. This is in part due to lack of observations, which are complicated due to the presence of energetic waves, strong (tidal) currents, dynamic seabed morphology, and often busy ship traffic. Conventional (fixed) instruments, such as buoys and bottom-mounted current or pressure sensors, are difficult to maintain in such areas, and the spatial variability of the wave field is difficult to capture with single point measurements, or even arrays of fixed measurements. In addition to the observational difficulties, the effects of e.g. current shear, wave blocking, statistical inhomogeneity [see Smit & Janssen, 2013, J. Phys. Ocean., 43, pp 1741-1758], and nonlinearity [see Janssen & Herbers, 2009, J. Phys Ocean., 39, pp 1948-1964] on wave statistics are not fully understood, not accounted for in operational stochastic wave models, and - as a consequence - often ignored. In this paper, we consider new observational data of waves approaching the Mouth of the Columbia River undergoing bottom refraction and strong wave-current interaction. The data were collected during the 2013 ONR RIVET experiment using an array of free drifting wave-current buoys. The Lagrangian instruments capture the spatial variability of the wave field in the inlet and, by deploying them in large ensembles, resolve the (inhomogeneous and nonlinear) wave statistics in the focal zone. We discuss the use of free-drifting instruments to measure wave statistics in a coastal wave focal zone, consider the observed effects of wave inhomogeneity, and show that non-Gaussian effects are important and affect extreme wave occurrences in the Mouth of the Columbia River.

  11. Focal hepatic infarction with bile lake formation

    SciTech Connect

    Peterson, I.M.; Neumann, C.H.

    1984-06-01

    Venous thrombosis associated with oral contraceptives is a well recognized phenomenon. Arterial thrombosis, while less common, is also a known risk, as evidenced by the increased incidence of cerebral vascular accidents and myocardial ischemia or infarction. The liver is relatively protected from the usual consequences of arterial thrombosis because of its dual blood supply. The authors present an unusual case of a young woman with a history of oral contraceptive and cigarette use who developed hepatic artery thrombosis and had focal liver lesions on computed tomography (CT) due to hepatic infarction and bile lake formation despite an intact portal venous system.

  12. Characterization of DECam focal plane detectors

    SciTech Connect

    Diehl, H.Thomas; Angstadt, Robert; Campa, Julia; Cease, Herman; Derylo, Greg; Emes, John H.; Estrada, Juan; Kibik, Donna; Flaugher, Brenna L.; Holland, Steve E.; Jonas, Michelle; /Fermilab /Madrid, CIEMAT /LBL, Berkeley /Argonne /Pennsylvania U.

    2008-06-01

    DECam is a 520 Mpix, 3 square-deg FOV imager being built for the Blanco 4m Telescope at CTIO. This facility instrument will be used for the 'Dark Energy Survey' of the southern galactic cap. DECam has chosen 250 ?m thick CCDs, developed at LBNL, with good QE in the near IR for the focal plane. In this work we present the characterization of these detectors done by the DES team, and compare it to the DECam technical requirements. The results demonstrate that the detectors satisfy the needs for instrument.

  13. Reading Text While Driving

    PubMed Central

    Horrey, William J.; Hoffman, Joshua D.

    2015-01-01

    Objective In this study, we investigated how drivers adapt secondary-task initiation and time-sharing behavior when faced with fluctuating driving demands. Background Reading text while driving is particularly detrimental; however, in real-world driving, drivers actively decide when to perform the task. Method In a test track experiment, participants were free to decide when to read messages while driving along a straight road consisting of an area with increased driving demands (demand zone) followed by an area with low demands. A message was made available shortly before the vehicle entered the demand zone. We manipulated the type of driving demands (baseline, narrow lane, pace clock, combined), message format (no message, paragraph, parsed), and the distance from the demand zone when the message was available (near, far). Results In all conditions, drivers started reading messages (drivers’ first glance to the display) before entering or before leaving the demand zone but tended to wait longer when faced with increased driving demands. While reading messages, drivers looked more or less off road, depending on types of driving demands. Conclusions For task initiation, drivers avoid transitions from low to high demands; however, they are not discouraged when driving demands are already elevated. Drivers adjust time-sharing behavior according to driving demands while performing secondary tasks. Nonetheless, such adjustment may be less effective when total demands are high. Application This study helps us to understand a driver’s role as an active controller in the context of distracted driving and provides insights for developing distraction interventions. PMID:25850162

  14. BB0347, from the Lyme Disease Spirochete Borrelia burgdorferi, Is Surface Exposed and Interacts with the CS1 Heparin-Binding Domain of Human Fibronectin

    PubMed Central

    Gaultney, Robert A.; Gonzalez, Tammy; Floden, Angela M.; Brissette, Catherine A.

    2013-01-01

    The causative agent of Lyme disease, Borrelia burgdorferi, codes for several known fibronectin-binding proteins. Fibronectin a common the target of diverse bacterial pathogens, and has been shown to be essential in allowing for the development of certain disease states. Another borrelial protein, BB0347, has sequence similarity with these other known fibronectin-binding proteins, and may be important in Lyme disease pathogenesis. Herein, we perform an initial characterization of BB0347 via the use of molecular and biochemical techniques. We found that BB0347 is expressed, produced, and presented on the outer surface of intact B. burgdorferi. We also demonstrate that BB0347 has the potential to be important in Lyme disease progression, and have begun to characterize the nature of the interaction between human fibronectin and this bacterial protein. Further work is needed to define the role of this protein in the borrelial infection process. PMID:24086600

  15. Piezoelectric drive circuit

    DOEpatents

    Treu, C.A. Jr.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes. 7 figs.

  16. Piezoelectric drive circuit

    DOEpatents

    Treu, Jr., Charles A.

    1999-08-31

    A piezoelectric motor drive circuit is provided which utilizes the piezoelectric elements as oscillators and a Meacham half-bridge approach to develop feedback from the motor ground circuit to produce a signal to drive amplifiers to power the motor. The circuit automatically compensates for shifts in harmonic frequency of the piezoelectric elements due to pressure and temperature changes.

  17. Dual drive actuators

    NASA Technical Reports Server (NTRS)

    Packard, D. T.

    1982-01-01

    A new class of electromechanical actuators is described. These dual drive actuators were developed for the NASA-JPL Galileo Spacecraft. The dual drive actuators are fully redundant and therefore have high inherent reliability. They can be used for a variety of tasks, and they can be fabricated quickly and economically.

  18. Characterization of the KATRIN Focal Plane Detector

    NASA Astrophysics Data System (ADS)

    Bodine, Laura; Leber, Michelle; Myers, Allan; Tolich, Kazumi; Vandevender, Brent; Wall, Brandon

    2008-10-01

    The Karlsruhe Tritium Neutrino (KATRIN) Experiment is a next generation tritium beta decay experiment designed to measure directly the electron neutrino mass with a sensitivity of 0.2 eV. In the experiment, electrons from tritium decay of a gaseous source are magnetically guided through analyzing solenoidal retarding electrostatic spectrometers and detected via a focal plane detector. The focal plane detector is a 90mm diameter, 500 micron thick monolithic silicon pin-diode array with 148 pixels. The diode contacts have a titanium nitride overlayer and are connected to preamplifiers via an array of spring-loaded pogo pins. This novel connection scheme minimizes backgrounds from radioactive materials near the detector, facilitates characterization and replacement of the detector wafer, but requires a unique mounting design. The force of the pins strains the silicon, possibly altering the detector properties and performance. Results on the mechanical, thermal and electrical performance of a prototype detector under stress from pogo pin readouts will be presented.

  19. Visual function and perinatal focal cerebral infarction.

    PubMed Central

    Mercuri, E; Atkinson, J; Braddick, O; Anker, S; Nokes, L; Cowan, F; Rutherford, M; Pennock, J; Dubowitz, L

    1996-01-01

    AIMS: To evaluate the visual function of infants with perinatal cerebral infarction in whom the site and size of the lesion has been determined using magnetic resonance imaging (MRI). METHODS: Twelve infants with cerebral infarction on MRI were studied with a battery of tests specifically designed to evaluate visual function in infancy. This included tests: for visual attention (fixation shifts); of cerebral asymmetry (optokinetic nystagmus, visual fields); for assessment of acuity (forced choice preferential looking); and neurophysiological measures of vision (phase reversal and orientation reversal visual evoked potential). RESULTS: A considerable incidence of abnormalities on at least one of the tests for visual function used was observed. The presence or severity of visual abnormalities could not always be predicted by the site and extent of the lesion seen on imaging. CONCLUSIONS: Early focal lesions affecting the visual pathway can, to some extent, be compensated for by the immature developing brain. These data suggest that all the infants presenting with focal lesions need to be investigated with a detailed assessment of various aspects of vision. Images PMID:8949687

  20. Ultrasound elastographic techniques in focal liver lesions

    PubMed Central

    Conti, Clara Benedetta; Cavalcoli, Federica; Fraquelli, Mirella; Conte, Dario; Massironi, Sara

    2016-01-01

    Elastographic techniques are new ultrasound-based imaging techniques developed to estimate tissue deformability/stiffness. Several ultrasound elastographic approaches have been developed, such as static elastography, transient elastography and acoustic radiation force imaging methods, which include point shear wave and shear wave imaging elastography. The application of these methods in clinical practice aims at estimating the mechanical tissues properties. One of the main settings for the application of these tools has been liver stiffness assessment in chronic liver disease, which has been studied mainly using transient elastography. Another field of application for these techniques is the assessment of focal lesions, detected by ultrasound in organs such as pancreas, prostate, breast, thyroid, lymph nodes. Considering the frequency and importance of the detection of focal liver lesions through routine ultrasound, some studies have also aimed to assess the role that elestography can play in studying the stiffness of different types of liver lesions, in order to predict their nature and thus offer valuable non-invasive methods for the diagnosis of liver masses. PMID:26973405

  1. Idiopathic focal epilepsies: the "lost tribe".

    PubMed

    Pal, Deb K; Ferrie, Colin; Addis, Laura; Akiyama, Tomoyuki; Capovilla, Giuseppe; Caraballo, Roberto; de Saint-Martin, Anne; Fejerman, Natalio; Guerrini, Renzo; Hamandi, Khalid; Helbig, Ingo; Ioannides, Andreas A; Kobayashi, Katsuhiro; Lal, Dennis; Lesca, Gaetan; Muhle, Hiltrud; Neubauer, Bernd A; Pisano, Tiziana; Rudolf, Gabrielle; Seegmuller, Caroline; Shibata, Takashi; Smith, Anna; Striano, Pasquale; Strug, Lisa J; Szepetowski, Pierre; Valeta, Thalia; Yoshinaga, Harumi; Koutroumanidis, Michalis

    2016-09-01

    The term idiopathic focal epilepsies of childhood (IFE) is not formally recognised by the ILAE in its 2010 revision (Berg et al., 2010), nor are its members and boundaries precisely delineated. The IFEs are amongst the most commonly encountered epilepsy syndromes affecting children. They are fascinating disorders that hold many "treats" for both clinicians and researchers. For example, the IFEs pose many of the most interesting questions central to epileptology: how are functional brain networks involved in the manifestation of epilepsy? What are the shared mechanisms of comorbidity between epilepsy and neurodevelopmental disorders? How do focal EEG discharges impact cognitive functioning? What explains the age-related expression of these syndromes? Why are EEG discharges and seizures so tightly locked to slow-wave sleep? In the last few decades, the clinical symptomatology and the respective courses of many IFEs have been described, although they are still not widely appreciated beyond the specialist community. Most neurologists would recognise the core syndromes of IFE to comprise: benign epilepsy of childhood with centro-temporal spikes or Rolandic epilepsy (BECTS/RE); Panayiotopoulos syndrome; and the idiopathic occipital epilepsies (Gastaut and photosensitive types). The Landau-Kleffner syndrome and the related (idiopathic) epilepsy with continuous spikes and waves in sleep (CSWS or ESES) are also often included, both as a consequence of the shared morphology of the interictal discharges and their potential evolution from core syndromes, for example, CSWS from BECTS. Atypical benign focal epilepsy of childhood also has shared electro-clinical features warranting inclusion. In addition, a number of less well-defined syndromes of IFE have been proposed, including benign childhood seizures with affective symptoms, benign childhood epilepsy with parietal spikes, benign childhood seizures with frontal or midline spikes, and benign focal seizures of adolescence. The

  2. Focal embolic cerebral ischemia in the rat

    PubMed Central

    Zhang, Li; Zhang, Rui Lan; Jiang, Quan; Ding, Guangliang; Chopp, Michael; Zhang, Zheng Gang

    2015-01-01

    Animal models of focal cerebral ischemia are well accepted for investigating the pathogenesis and potential treatment strategies for human stroke. Occlusion of the middle cerebral artery (MCA) with an endovascular filament is a widely used model to induce focal cerebral ischemia. However, this model is not amenable to thrombolytic therapies. As thrombolysis with recombinant tissue plasminogen activator (rtPA) is a standard of care within 4.5 hours of human stroke onset, suitable animal models that mimic cellular and molecular mechanisms of thrombosis and thrombolysis of stroke are required. By occluding the MCA with a fibrin-rich allogeneic clot, we have developed an embolic model of MCA occlusion in the rat, which recapitulates the key components of thrombotic development and of thrombolytic therapy of rtPA observed from human ischemic stroke. The surgical procedures of our model can be typically completed within approximately 30 min and are highly adaptable to other strains of rats as well as mice for both genders. Thus, this model provides a powerful tool for translational stroke research. PMID:25741989

  3. Posttraumatic focal dystonia of the shoulder.

    PubMed

    Vasileiadis, Georgios I; Sakellariou, Vasileios I; Papagelopoulos, Panayiotis J; Zoubos, Aristeides B

    2012-06-01

    Focal posttraumatic shoulder dystonia is a rare and not easily identifiable entity. Its true pathophysiologic nature, predisposing factors, and disease course remain debatable.This article describes a rare case of a 40-year-old man with late symptoms of focal shoulder dystonia after peripheral trauma of his left shoulder girdle. The shoulder was indirectly injured from the impact of a fall off his motorbike 3 years earlier. He was referred to the authors' institution because remarkable reduction of arm abduction, muscle spasms, and circumscribed hypertrophy of the trapezius muscle were noted while his head and neck were in neutral position and had a full range of motion. The left shoulder had a fixed elevated posture compared with the contralateral shoulder. A continuous burning pain was localized over the area of the hypertrophied trapezius muscle, radiating to the ipsilateral side of the head and neck. Dystonic movements of the trapezius, rhomboid, and supraspinatus muscles were observed. The abduction of the shoulder was significantly decreased, and any repetitive effort for arm abduction induced an exaggeration of his movement disorder, leading to a more pronounced shoulder elevation.Plain radiographs and magnetic resonance imaging of the left shoulder revealed a suprascapular tendinitis with no other abnormalities. Repeated needle electromyography of the left trapezius muscle and neurography of the accessory nerve on both sides were normal. Injections of botulinum toxin A were effective in the resolution of muscle hypertrophy and abnormal posture. PMID:22691679

  4. Short Wavelength Infrared Hybrid Focal Plane Arrays

    NASA Astrophysics Data System (ADS)

    Vural, K.; Blackwell, J. D...; Marin, E. C.; Edwall, D. D...; Rode, J. P.

    1983-11-01

    Short wavelength (λc = 2.5 μm) 32 x 32 HgCdTe focal plane arrays have been fabricated for use in an Airborne Imaging Spectrometer (AIS) developed by the Jet Propulsion Labora-tory for NASA. An Imaging Spectrometer provides simultaneous imaging of several spectral bands for applications in the sensing and monitoring of earth resources. The detector material is HgCdTe grown on CdTe substrates using liquid phase epitaxy. Planar processing is used to make photovoltaic detectors on 68 um centers. The detector array is mated to a silicon charge coupled device multiplexer to make hybrid focal plane arrays. Results show high performance detectors with a mean RoA = 9.6 x 107 Ω --cm2 and IleakAge (-100 mV) = 0.037 pA at 120K and near zero background. The yield and uniformity are high. The ratio of the standard deviation of the dc responsivity to the mean is 3% for 98.5% of the pixels. The D1.0 = 1.3 x 1012 cm - âœ"fiz/W at a background of 1013 ph/cm2-s and 120K which is close to the background limited (BLIP) D* of 1.9 x 1012 cm- âœ"Hz/W.

  5. ORFEUS focal plane instrumentation: The Berkeley spectrometer

    NASA Technical Reports Server (NTRS)

    Hurwitz, Mark; Bowyer, Stuart

    1988-01-01

    A spectrograph for the ORFEUS mission that incorporates four varied line-space, spherically figured diffraction gratings was designed. The ORFEUS, a 1-m normal incidence telescope is equipped with 2 focal plane spectrographs. The Berkeley spectrograph was developed with an optimizing raytracing computer code. Each grating accepts the light from 20 percent of the aperture of the telescope primary mirror and has a unique set of characteristics to cover a sub-bandpass within the 390 to 1200 A spectral range. Two photon-counting detectors incorporating a time delay readout system are used to record the spectra from all four gratings simultaneously. The nominal design achieves a spectral resolution (FWHM) in excess of 5500 at all wavelengths within the bandpass. The resolution is limited primarily by the detector spatial resolution. The 1 sigma astigmatism of this design varies between 13 and 150 micrometer on the same focal surface. An independent, direct imaging system tracks the drift of the target within the spectrometer aperture and allows measurement of the misalignment between the telescope optical axis and that of the external star tracker. The resolution and astigmatism achievable with this design are superior to those of a standard Rowland spectrograph designed with the same constraints.

  6. The Piriform Cortex and Human Focal Epilepsy

    PubMed Central

    Vaughan, David N.; Jackson, Graeme D.

    2014-01-01

    It is surprising that the piriform cortex, when compared to the hippocampus, has been given relatively little significance in human epilepsy. Like the hippocampus, it has a phylogenetically preserved three-layered cortex that is vulnerable to excitotoxic injury, has broad connections to both limbic and cortical areas, and is highly epileptogenic – being critical to the kindling process. The well-known phenomenon of early olfactory auras in temporal lobe epilepsy highlights its clinical relevance in human beings. Perhaps because it is anatomically indistinct and difficult to approach surgically, as it clasps the middle cerebral artery, it has, until now, been understandably neglected. In this review, we emphasize how its unique anatomical and functional properties, as primary olfactory cortex, predispose it to involvement in focal epilepsy. From recent convergent findings in human neuroimaging, clinical epileptology, and experimental animal models, we make the case that the piriform cortex is likely to play a facilitating and amplifying role in human focal epileptogenesis, and may influence progression to epileptic intractability. PMID:25538678

  7. Small pixel oversampled IR focal plane arrays

    NASA Astrophysics Data System (ADS)

    Caulfield, John; Curzan, Jon; Lewis, Jay; Dhar, Nibir

    2015-06-01

    We report on a new high definition high charge capacity 2.1 Mpixel MWIR Infrared Focal Plane Array. This high definition (HD) FPA utilizes a small 5 um pitch pixel size which is below the Nyquist limit imposed by the optical systems Point Spread Function (PSF). These smaller sub diffraction limited pixels allow spatial oversampling of the image. We show that oversampling IRFPAs enables improved fidelity in imaging including resolution improvements, advanced pixel correlation processing to reduce false alarm rates, improved detection ranges, and an improved ability to track closely spaced objects. Small pixel HD arrays are viewed as the key component enabling lower size, power and weight of the IR Sensor System. Small pixels enables a reduction in the size of the systems components from the smaller detector and ROIC array, the reduced optics focal length and overall lens size, resulting in an overall compactness in the sensor package, cooling and associated electronics. The highly sensitive MWIR small pixel HD FPA has the capability to detect dimmer signals at longer ranges than previously demonstrated.

  8. Multiple molecular penumbras after focal cerebral ischemia.

    PubMed

    Sharp, F R; Lu, A; Tang, Y; Millhorn, D E

    2000-07-01

    Though the ischemic penumbra has been classically described on the basis of blood flow and physiologic parameters, a variety of ischemic penumbras can be described in molecular terms. Apoptosis-related genes induced after focal ischemia may contribute to cell death in the core and the selective cell death adjacent to an infarct. The HSP70 heat shock protein is induced in glia at the edges of an infarct and in neurons often at some distance from the infarct. HSP70 proteins are induced in cells in response to denatured proteins that occur as a result of temporary energy failure. Hypoxia-inducible factor (HIF) is also induced after focal ischemia in regions that can extend beyond the HSP70 induction. The region of HIF induction is proposed to represent the areas of decreased cerebral blood flow and decreased oxygen delivery. Immediate early genes are induced in cortex, hippocampus, thalamus, and other brain regions. These distant changes in gene expression occur because of ischemia-induced spreading depression or depolarization and could contribute to plastic changes in brain after stroke. PMID:10908035

  9. Focal Adhesion Kinase-Dependent Regulation of Adhesive Force Involves Vinculin Recruitment to Focal Adhesions

    PubMed Central

    Hanks, Steven K.; García, Andrés J.

    2016-01-01

    Background information Focal adhesion kinase (FAK), an essential non-receptor tyrosine kinase, plays pivotal roles in migratory responses, adhesive signaling, and mechanotransduction. FAK-dependent regulation of cell migration involves focal adhesion turnover dynamics as well as actin cytoskeleton polymerization and lamellipodia protrusion. Whereas roles for FAK in migratory and mechanosensing responses have been established, the contributions of FAK to the generation of adhesive forces are not well understood. Results Using FAK-null cells expressing wild-type and mutant FAK under an inducible tetracycline promoter, we analyzed the role of FAK in the generation of steady-state adhesive forces using micropatterned substrates and a hydrodynamic adhesion assay. FAK expression reduced steady-state strength by 30% compared to FAK-null cells. FAK expression reduced vinculin localization to focal adhesions by 35% independently from changes in integrin binding and localization of talin and paxillin. RNAi knockdown of vinculin abrogated the FAK-dependent differences in adhesive force. FAK-dependent changes in vinculin localization and adhesive force were confirmed in human primary fibroblasts with FAK knocked down by RNAi. The autophosphorylation Y397 and kinase domain Y576/Y577 sites were differentially required for FAK-mediated adhesive responses. Conclusions We demonstrate that FAK reduces steady-state adhesion strength by modulating vinculin recruitment to focal adhesions. These findings provide insights into the role of FAK in mechanical interactions between a cell and the extracellular matrix. PMID:19883375

  10. Design of traction drives

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Zaretsky, E. V.

    1985-01-01

    Traction drives are among the simplest of all speed-changing mechanisms. Because of their simplicity and their ability to smoothly and continuously adjust speed, they are excellent choices for many drive system applications. They have been used in industrial service for more than 100 years. Today's traction drives have power capacities which rival the best gear and belt drives due to modern traction fluids and highly fatigue-resistant bearing steels. This report summarizes methods to analyze and size traction drives. Lubrication principles, contact kinematics, stress, fatigue life, and performance prediction methods are presented. The effects of the lubricant's traction characteristics on life and power loss are discussed. An example problem is given which illustrates the effects of spin on power loss. Loading mechanism design and the design of nonlubricated friction wheels and rings are also treated.

  11. An RGD spacing of 440 nm is sufficient for integrin alpha V beta 3- mediated fibroblast spreading and 140 nm for focal contact and stress fiber formation

    PubMed Central

    1991-01-01

    The synthetic peptide Gly-Arg-Gly-Asp-Tyr (GRGDY), which contains the RGD sequence of several adhesion molecules, was covalently grafted to the surface of otherwise poorly adhesive glass substrates and was used to determine the minimal number of ligand-receptor interactions required for complete spreading of human foreskin fibroblasts. Well- defined adhesion substrates were prepared with GRGDY between 10(-3) fmol/cm2 and 10(4) fmol/cm2. As the adhesion ligand surface concentration was varied, several distinct morphologies of adherent cells were observed and categorized. The population of fully spread cells at 4 h reached a maximum at 1 fmol/cm2, with no further increases up to 10(4) fmol/cm2. Although maximal cell spreading was obtained at 1 fmol/cm2, focal contacts and stress fibers failed to form at RGD surface concentrations below 10 fmol/cm2. The minimal peptide spacings obtained in this work correspond to 440 nm for spreading and 140 nm for focal contact formation, and are much larger than those reported in previous studies with adsorbed adhesion proteins, adsorbed RGD-albumin conjugates, or peptide-grafted polyacrylamide gels. Vitronectin receptor antiserum specific for integrin alpha V beta 3 blocked cell adhesion and spreading on substrates containing 100 fmol/cm2 of surface- bound GRGDY, while fibronectin receptor antiserum specific for alpha 5 beta 1 did not. Furthermore, alpha V beta 3 was observed to cluster into focal contacts in spread cells, but alpha 5 beta 1 did not. It was thus concluded that a peptide-to-peptide spacing of 440 nm was required for alpha V beta 3-mediated cellular spreading, while 140 nm was required for alpha V beta 3-mediated focal contact formation and normal stress fiber organization in human foreskin fibroblasts; these spacings represent much fewer ligands than were previously thought to be required. PMID:1714913

  12. The ShdA adhesin binds to the cationic cradle of the fibronectin 13FnIII repeat module: evidence for molecular mimicry of heparin binding.

    PubMed

    Kingsley, Robert A; Keestra, A Marijke; de Zoete, Marcel R; Bäumler, Andreas J

    2004-04-01

    Introduction of Salmonella enterica serotype Typhimurium into food products results from its ability to persist in the intestine of healthy livestock by mechanisms that are poorly understood. The non-fimbrial adhesin ShdA is a fibronectin binding protein required for persistent intestinal carriage of S. Typhimurium. We further investigated the molecular mechanism of ShdA-mediated intestinal persistence by determining the binding-site of this receptor in fibronectin. Analysis of ShdA binding to fibronectin proteolytic fragments and to recombinant fibronectin fusion proteins identified the (13)FnIII repeat module of the Hep-2 domain as the primary binding site for this adhesin. The (13)FnIII repeat module of fibronectin contains a cationic cradle formed by six basic residues (R6, R7, R9, R23, K25 and R54) that is a high affinity heparin-binding site conserved among fibronectin sequences from frogs to man. Binding of ShdA to the (13)FnIII repeat module of fibronectin and to a second extracellular matrix protein, Collagen I, could be inhibited by heparin. Furthermore, binding of ShdA to the Hep-2 domain was sensitive to the ionic buffer strength, suggesting that binding involved ionic interactions. We therefore determined whether amino acid substitutions of basic residues in the cationic cradle of the Hep-2 domain that inhibit heparin binding also abrogate binding of ShdA. Combined substitution of R6S and R7S strongly reduced ShdA binding to (13)FnIII. These data suggest that ShdA binds the Hep-2 domain of fibronectin by a mechanism that may mimic binding of the host polysaccharide heparin. PMID:15066025

  13. Induction of Fibronectin-Binding Proteins and Increased Adhesion of Quinolone-Resistant Staphylococcus aureus by Subinhibitory Levels of Ciprofloxacin

    PubMed Central

    Bisognano, Carmelo; Vaudaux, Pierre; Rohner, Peter; Lew, Daniel P.; Hooper, David C.

    2000-01-01

    We recently reported that strain EN1252a, a fluoroquinolone-resistant derivative of Staphylococcus aureus NCTC8325 with mutations in grlA and gyrA, expressed increased levels of fibronectin-binding proteins (FnBPs) and showed a significantly higher attachment to fibronectin-coated polymer surfaces after growth in the presence of subinhibitory concentrations of ciprofloxacin. The present study evaluated the occurrence and frequency of fluoroquinolone-induced FnBP-mediated adhesion in clinical isolates of fluoroquinolone-resistant methicillin-resistant S. aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). Eight of ten MRSA isolates and four of six MSSA isolates with grlA and gyrA mutations exhibited significant increases in attachment to fibronectin-coated surfaces after growth in the presence of one-quarter the MIC of ciprofloxacin. Fluoroquinolone-induced FnBP-mediated adhesion of one clinical MRSA strain and the double mutant strain EN1252a also occurred on coverslips removed from the subcutaneous space of guinea pigs. For strain EN1252a, the regulation of fnb transcription by sub-MICs of ciprofloxacin was studied on reporter plasmids carrying fnb-luxAB fusions. One-quarter of the MIC of ciprofloxacin significantly increased fnbB, but not fnbA, promoter activity of the fluoroquinolone-resistant mutant but not its fluoroquinolone-susceptible parent ISP794. This response was abolished by pretreatment with rifampin, indicating an effect at the level of transcription. Activation of the fnbB promoter was not due to an indirect effect of ciprofloxacin on growth rate and still occurred in an agr mutant of strain EN1252a. These data suggest that sub-MIC levels of ciprofloxacin activate the fnbB promoter of some laboratory and clinical isolates, thus contributing to increased production of FnBP(s) and leading to higher levels of bacterial attachment to fibronectin-coated or subcutaneously implanted coverslips. PMID:10817688

  14. Introduction of the mec Element (Methicillin Resistance) into Staphylococcus aureus Alters In Vitro Functional Activities of Fibrinogen and Fibronectin Adhesins

    PubMed Central

    Vaudaux, Pierre E.; Monzillo, Vincenza; Francois, Patrice; Lew, Daniel P.; Foster, Tim J.; Berger-Bächi, Brigitte

    1998-01-01

    Some methicillin-resistant strains of Staphylococcus aureus are defective in the production of major surface components such as protein A, clumping factor, or other important adhesins to extracellular matrix components which may play a role in bacterial colonization and infection. To evaluate the impact of methicillin resistance (mec) determinants on bacterial adhesion mediated by fibrinogen or fibronectin adhesins, we compared the in vitro attachment of two genetically distinct susceptible strains (NCTC8325 and Newman) to protein-coated surfaces with that of isogenic methicillin-resistant derivatives. All strains containing an intact mec element in their chromosomes were found to be defective in adhesion to fibrinogen and fibronectin immobilized on polymethylmethacrylate coverslips, regardless of the presence or absence of additional mutations in the femA, femB, or femC gene, known to decrease expression of methicillin resistance in S. aureus. Western ligand affinity blotting or immunoblotting of cell wall-associated adhesins revealed similar contents of fibrinogen- or fibronectin-binding proteins in methicillin-resistant strains compared to those of their methicillin-susceptible counterparts. In contrast to methicillin-resistant strains carrying a mec element in their genomes, methicillin-resistant strains constructed in vitro, by introducing the mecA gene on a plasmid, retained their adhesion phenotypes. In conclusion, the chromosomal insertion of the mec element into genetically defined strains of S. aureus impairs the in vitro functional activities of fibrinogen or fibronectin adhesins without altering their production. This effect is unrelated to the activity of the mecA gene. PMID:9517933

  15. Increased expression of fibronectin-binding proteins by fluoroquinolone-resistant Staphylococcus aureus exposed to subinhibitory levels of ciprofloxacin.

    PubMed Central

    Bisognano, C; Vaudaux, P E; Lew, D P; Ng, E Y; Hooper, D C

    1997-01-01

    Bacterial adhesion, which plays an important role in Staphylococcus aureus colonization and infection, may be altered by the presence of antibiotics or/and antibiotic resistance determinants. This study evaluated the effect of fluoroquinolone resistance determinants on S. aureus adhesion to solid-phase fibronectin, which is specifically mediated by two surface-located fibronectin-binding proteins. Five isogenic mutants, derived from strain NCTC 8325 and expressing various levels of quinolone resistance, were tested in an in vitro bacterial adhesion assay with polymethylmethacrylate coverslips coated with increasing amounts of fibronectin. These strains contained single or combined mutations in the three major loci contributing to fluoroquinolone resistance, namely, grlA, gyrA, and flqB, which code for altered topoisomerase IV, DNA gyrase, and increased norA-mediated efflux of fluoroquinolones, respectively. Adhesion characteristics of the different quinolone-resistant mutants grown in the absence of fluoroquinolone showed only minor differences from those of parental strains. However, more important changes in adhesion were exhibited by mutants highly resistant to quinolones following their exponential growth in the presence of one-quarter MIC of ciprofloxacin. Increased bacterial adhesion of the highly quinolone-resistant mutants, which contained combined mutations in grlA and gyrA, was associated with and explained by the overexpression of their fibronectin-binding proteins as assessed by Western ligand affinity blotting. These findings contradict the notion that subinhibitory concentrations of antibiotics generally decrease the expression of virulence factors by S. aureus. Perhaps the increased adhesion of S. aureus strains highly resistant to fluoroquinolones contributes in part to that emergence in clinical settings. PMID:9145842

  16. In vitro behavior of a porous TiO2/perlite composite and its surface modification with fibronectin.

    PubMed

    von Walter, Matthias; Rüger, Matthias; Ragoss, Christian; Steffens, Guy C M; Hollander, Dirk A; Paar, Othmar; Maier, Horst R; Jahnen-Dechent, Willi; Bosserhoff, Anja K; Erli, Hans-Josef

    2005-06-01

    In this study, we introduce a porous composite material, termed "Ecopore", and describe in vitro investigation of the material and its modification with fibronectin. The material is a sintered compound of rutile TiO2 and the volcanic silicate perlite with a macrostructure of interconnecting pores. It is both inexpensive and easy to manufacture. We first investigated Ecopore for corrosion and leaching of elements in physiological saline. The corrosion supernatants did not contain critical concentrations of toxic trace elements. In an in vitro model, human primary osteoblasts (HOB) were cultured directly on Ecopore. HOB grew on the composite as well as on samples of its single constituents, TiO2 and perlite glass, and remained vital, but cellular spreading was less than on tissue culture plastic. The pro-inflammatory cytokines IL-1 and TNF-alpha were below detection limits in HOB culture supernatants, whereas IL-6 was detectable on a low level. To enhance cellular attachment and growth, the surface of the composite was modified by etching, functionalization with aminosilane and coupling of fibronectin. This modification greatly enhanced the spreading of HOB, indicated by vital staining and Sodium 3'-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) benzene sulfonic acid hydrate (XTT) metabolism assays. HOB grew on the entire visible surface of porous fibronectin-modified composite, expressing alkaline phosphatase, a mature osteoblast marker. We conclude that Ecopore is non-toxic and sustains HOB growth, cellular spreading being improvable by coating with fibronectin. The composite may be usable in the field of bone substitution. PMID:15603777

  17. Megakaryocytes contribute to the bone marrow-matrix environment by expressing fibronectin, type IV collagen and laminin

    PubMed Central

    Malara, Alessandro; Currao, Manuela; Gruppi, Cristian; Celesti, Giuseppe; Viarengo, Gianluca; Buracchi, Chiara; Laghi, Luigi; Kaplan, David L.; Balduini, Alessandra

    2014-01-01

    Megakaryocytes associate with the bone marrow vasculature where they convert their cytoplasm into proplatelets that protrude through the vascular endothelium into the lumen and release platelets. The extracellular matrix (ECM) microenvironment plays a critical role in regulating these processes. In this work we demonstrate that, among bone marrow ECM components, fibronectin, type IV collagen and laminin are the most abundant around bone marrow sinusoids and constitute a peri-cellular matrix surrounding megakaryocytes. Most importantly, we report, for the first time, that megakaryocytes express components of the basement membrane and that these molecules contribute to the regulation of megakaryocyte development and bone marrow ECM homeostasis both in vitro and in vivo. In vitro, fibronectin induced a three-fold increase in the proliferation rate of mouse hematopoietic stem cells leading to higher megakaryocyte output with respect to cells treated only with thrombopoietin or other matrices. However, megakaryocyte ploidy level in fibronectin-treated cultures was significantly reduced. Stimulation with type IV collagen resulted in a 1.4-fold increase in megakaryocyte output, while all tested matrices supported proplatelet formation to a similar extent in megakaryocytes derived from fetal liver progenitor cells. In vivo, megakaryocyte expression of fibronectin and basement membrane components was up-regulated during bone marrow reconstitution upon 5-fluorouracil induced myelosuppression, while only type IV collagen resulted up-regulated upon induced thrombocytopenia. In conclusion, this work demonstrates that ECM components impact megakaryocyte behavior differently during their differentiation and highlights a new role for megakaryocyte as ECM-producing cells for the establishment of cell niches during bone marrow regeneration. PMID:24357118

  18. Fibronectin Binding Proteins SpsD and SpsL Both Support Invasion of Canine Epithelial Cells by Staphylococcus pseudintermedius

    PubMed Central

    Pietrocola, Giampiero; Gianotti, Valentina; Richards, Amy; Nobile, Giulia; Geoghegan, Joan A.; Rindi, Simonetta; Monk, Ian R.; Bordt, Andrea S.; Foster, Timothy J.; Fitzgerald, J. Ross

    2015-01-01

    In this study, we investigated the cell wall-anchored fibronectin-binding proteins SpsD and SpsL from the canine commensal and pathogen Staphylococcus pseudintermedius for their role in promoting bacterial invasion of canine progenitor epidermal keratinocytes (CPEK). Invasion was examined by the gentamicin protection assay and fluorescence microscopy. An ΔspsD ΔspsL mutant of strain ED99 had a dramatically reduced capacity to invade CPEK monolayers, while no difference in the invasion level was observed with single mutants. Lactococcus lactis transformed with plasmids expressing SpsD and SpsL promoted invasion, showing that both proteins are important. Soluble fibronectin was required for invasion, and an RGD-containing peptide or antibodies recognizing the integrin α5β1 markedly reduced invasion, suggesting an important role for the integrin in this process. Src kinase inhibitors effectively blocked internalization, suggesting a functional role for the kinase in invasion. In order to identify the minimal fibronectin-binding region of SpsD and SpsL involved in the internalization process, recombinant fragments of both proteins were produced. The SpsD520–846 and SpsL538–823 regions harboring the major fibronectin-binding sites inhibited S. pseudintermedius internalization. Finally, the effects of staphylococcal invasion on the integrity of different cell lines were examined. Because SpsD and SpsL are critical factors for adhesion and invasion, blocking these processes could provide a strategy for future approaches to treating infections. PMID:26238710

  19. Real-time analysis of imatinib- and dasatinib-induced effects on chronic myelogenous leukemia cell interaction with fibronectin.

    PubMed

    Obr, Adam; Röselová, Pavla; Grebeňová, Dana; Kuželová, Kateřina

    2014-01-01

    Attachment of stem leukemic cells to the bone marrow extracellular matrix increases their resistance to chemotherapy and contributes to the disease persistence. In chronic myelogenous leukemia (CML), the activity of the fusion BCR-ABL kinase affects adhesion signaling. Using real-time monitoring of microimpedance, we studied in detail the kinetics of interaction of human CML cells (JURL-MK1, MOLM-7) and of control BCR-ABL-negative leukemia cells (HEL, JURKAT) with fibronectin-coated surface. The effect of two clinically used kinase inhibitors, imatinib (a relatively specific c-ABL inhibitor) and dasatinib (dual ABL/SRC family kinase inhibitor), on cell binding to fibronectin is described. Both imatinib and low-dose (several nM) dasatinib reinforced CML cell interaction with fibronectin while no significant change was induced in BCR-ABL-negative cells. On the other hand, clinically relevant doses of dasatinib (100 nM) had almost no effect in CML cells. The efficiency of the inhibitors in blocking the activity of BCR-ABL and SRC-family kinases was assessed from the extent of phosphorylation at autophosphorylation sites. In both CML cell lines, SRC kinases were found to be transactivated by BCR-ABL. In the intracellular context, EC50 for BCR-ABL inhibition was in subnanomolar range for dasatinib and in submicromolar one for imatinib. EC50 for direct inhibition of LYN kinase was found to be about 20 nM for dasatinib and more than 10 µM for imatinib. Cells pretreated with 100 nM dasatinib were still able to bind to fibronectin and SRC kinases are thus not necessary for the formation of cell-matrix contacts. However, a minimal activity of SRC kinases might be required to mediate the increase in cell adhesivity induced by BCR-ABL inhibition. Indeed, active (autophosphorylated) LYN was found to localize in cell adhesive structures which were visualized using interference reflection microscopy. PMID:25198091

  20. Fibronectin Binding to the Salmonella enterica Serotype Typhimurium ShdA Autotransporter Protein Is Inhibited by a Monoclonal Antibody Recognizing the A3 Repeat

    PubMed Central

    Kingsley, Robert A.; Abi Ghanem, Daad; Puebla-Osorio, Nahum; Keestra, A. Marijke; Berghman, Luc; Bäumler, Andreas J.

    2004-01-01

    ShdA is a large outer membrane protein of the autotransporter family whose passenger domain binds the extracellular matrix proteins fibronectin and collagen I, possibly by mimicking the host ligand heparin. The ShdA passenger domain consists of ∼1,500 amino acid residues that can be divided into two regions based on features of the primary amino acid sequence: an N-terminal nonrepeat region followed by a repeat region composed of two types of imperfect direct amino acid repeats, called type A and type B. The repeat region bound bovine fibronectin with an affinity similar to that for the complete ShdA passenger domain, while the nonrepeat region exhibited comparatively low fibronectin-binding activity. A number of fusion proteins containing truncated fragments of the repeat region did not bind bovine fibronectin. However, binding of the passenger domain to fibronectin was inhibited in the presence of immune serum raised to one truncated fragment of the repeat region that contained repeats A2, B8, A3, and B9. Furthermore, a monoclonal antibody that specifically recognized an epitope in a recombinant protein containing the A3 repeat inhibited binding of ShdA to fibronectin. PMID:15262930

  1. Fibronectin binding to the Salmonella enterica serotype Typhimurium ShdA autotransporter protein is inhibited by a monoclonal antibody recognizing the A3 repeat.

    PubMed

    Kingsley, Robert A; Abi Ghanem, Daad; Puebla-Osorio, Nahum; Keestra, A Marijke; Berghman, Luc; Bäumler, Andreas J

    2004-08-01

    ShdA is a large outer membrane protein of the autotransporter family whose passenger domain binds the extracellular matrix proteins fibronectin and collagen I, possibly by mimicking the host ligand heparin. The ShdA passenger domain consists of approximately 1,500 amino acid residues that can be divided into two regions based on features of the primary amino acid sequence: an N-terminal nonrepeat region followed by a repeat region composed of two types of imperfect direct amino acid repeats, called type A and type B. The repeat region bound bovine fibronectin with an affinity similar to that for the complete ShdA passenger domain, while the nonrepeat region exhibited comparatively low fibronectin-binding activity. A number of fusion proteins containing truncated fragments of the repeat region did not bind bovine fibronectin. However, binding of the passenger domain to fibronectin was inhibited in the presence of immune serum raised to one truncated fragment of the repeat region that contained repeats A2, B8, A3, and B9. Furthermore, a monoclonal antibody that specifically recognized an epitope in a recombinant protein containing the A3 repeat inhibited binding of ShdA to fibronectin. PMID:15262930

  2. Gallium-67 uptake in the lung of asbestos exposed sheep: early association with enhanced macrophage-derived fibronectin accumulation

    SciTech Connect

    Begin, R.; Bisson, G.; Lambert, R.; Cote, Y.; Fabi, D.; Martel, M.; Lamoureux, G.; Rola-Pleszczynski, M.; Boctor, M.; Dalle, D.

    1986-04-01

    To evaluate the time course and mechanisms of enhanced /sup 67/Ga lung uptake in asbestosis, we exposed two groups of sheep every 2 wk to either 100 ml saline (controls) or 100 mg UICC chrysotile fibers in 100 ml saline. The sheep were evaluated periodically by pulmonary function tests (PFT), thoracic radiograph (TR), /sup 67/Ga lung scan, bronchoalveolar lavage (BAL), and transbronchial lung biopsy (TLB). By month 24 of the study, 9/15 exposed sheep had developed the initial alveolitis and had significant changes in PFT, TR, and TLB. The other six exposed sheep differed from controls only by a 75% increase in BAL fibronectin until month 30, where significant changes in albumin occurred and /sup 67/Ga scan score increased. The nine sheep with alveolitis had significant sustained increases in /sup 67/Ga scan and BAL levels from month 6, associated with a 150% increase in BAL fibronectin and other parameters of disease activity changed from month 18 to 30. We concluded that in the sheep model of asbestosis, significant changes in /sup 67/Ga scan, /sup 67/Ga BAL counts, and excessive elevation of BAL fibronectin preceded other parameters of disease activity. The data suggest that excessively activated macrophages are primarily responsible for the early /sup 67/Ga lung uptake.

  3. Deep Moonquake Focal Mechanisms: Recovery and Implications

    NASA Technical Reports Server (NTRS)

    Knapmeyer, Martin; Weber, Renee C.

    2011-01-01

    A defining characteristic of deep moonquakes is their tendency to occur with tidal periodicity, prompting previous studies to infer that they are related to the buildup and release of tidal stress within the Moon. In studies of tidal forcing, a key constraint is the focal mechanism: the fault parameters describing the type of failure moonquakes represent. The quality of the lunar seismic data and the limited source/receiver geometries of the Apollo seismic network prohibit the determination of deep moonquake fault parameters using first-motion polarities, as is typically done in terrestrial seismology. Without being able to resolve tidal stress onto a known failure plane, we can examine only gross qualities of the tidal stress tensor with respect to moonquake occurrence, so we cannot fully address the role of tidal stress in moonquake generation. We will examine the extent to which shear (S) and compression (P) wave amplitude ratios can constrain moonquake fault geometry by determining whether, for a given cluster, there exists a focal mechanism that can produce a radiation pattern consistent with the amplitudes measured by the Apollo instruments. Amplitudes are read in the ray coordinate frame, directly from seismograms for which the P and S arrivals are clearly identifiable on all long-period channels of the four Apollo stations. We apply an empirical station correction to account for site effects and the differences between P- and S-wave attenuation. Instead of focusing on the best fitting solution only, we formulate the inverse problem using a falsification criterion: all source orientations that do not reproduce the observed SV/P ratios within an error margin derived from the uncertainty of amplitude readings are rejected. All others are accepted as possible solutions. The inversion is carried out using an exhaustive grid search on a regular grid with predefined step size, encompassing all possible combinations of strike, dip and slip. To assess the

  4. Physical Activity Performance of Focal Middle School Students

    ERIC Educational Resources Information Center

    Erfle, Stephen E.; Gelbaugh, Corey M.

    2013-01-01

    Histograms of push-ups and curl-ups from a sample of more than 9,000 students show periodic spikes at five and 10 unit intervals. This article argues that these spikes are related to focal points, a game theoretic concept popularized by Nobel Laureate Thomas Schelling. Being focal on one test makes one more likely to be focal on the other. Focal…

  5. Vision and Driving

    PubMed Central

    Owsley, Cynthia; McGwin, Gerald

    2010-01-01

    Driving is the primary means of personal travel in many countries and is relies heavily on vision for its successful execution. Research over the past few decades has addressed the role of vision in driver safety (motor vehicle collision involvement) and in driver performance (both on-road and using interactive simulators in the laboratory). Here we critically review what is currently known about the role of various aspects of visual function in driving. We also discuss translational research issues on vision screening for licensure and re-licensure and rehabilitation of visually impaired persons who want to drive. PMID:20580907

  6. Redundant motor drive system

    NASA Technical Reports Server (NTRS)

    Calvert, J. A. (Inventor)

    1980-01-01

    A drive system characterized by a base supporting a pair of pillars arranged in spaced parallelism, a shaft extended between and supported by the pillars for rotation about the longitudinal axis thereof, a worm gear affixed to the shaft and supported in coaxial relation therewith is described. A bearing housing of a sleeve like configuration is concentrically related to the shaft and is supported thereby for free rotation. A first and a second quiescent drive train, alternatively activatable, is provided for imparting rotation into said bearing housing. Each of the drive trains is characterized by a selectively energizable motor connected to a spur gear.

  7. The Test Drive

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This image taken at NASA's Jet Propulsion Laboratory shows engineers rehearsing the sol 133 (June 8, 2004) drive into 'Endurance' crater by NASA's Mars Exploration Rover Opportunity. Engineers and scientists have recreated the martian surface and slope the rover will encounter using a combination of bare and thinly sand-coated rocks, simulated martian 'blueberries' and a platform tilted at a 25-degree angle. The results of this test convinced engineers that the rover was capable of driving up and down a straight slope before it attempted the actual drive on Mars.

  8. Oral focal mucinosis of palatal mucosa: A rare case report

    PubMed Central

    Bharti, Vipin; Singh, Jagmohan

    2012-01-01

    Oral focal mucinosis (OFM), an oral counterpart of cutaneous focal mucinosis, is a rare disease of unknown etiology. Its pathogenesis may be due to the overproduction of hyaluronic acid by a fibroblast, at the expense of collagen production, resulting in focal myxoid degeneration of the connective tissue, primarily affecting the mucosa overlying the bone. It has no distinctive clinical features, as the diagnosis is solely based on the histopathological features. This article reports of a 32-year-old female having the rare disease of oral focal mucinosis, involving the posterior palatal mucosa, and discusses its clinicopathological features and differential diagnosis of myxomatous lesions of the oral cavity. PMID:23230367

  9. Smart trigger logic for focal plane arrays

    SciTech Connect

    Levy, James E; Campbell, David V; Holmes, Michael L; Lovejoy, Robert; Wojciechowski, Kenneth; Kay, Randolph R; Cavanaugh, William S; Gurrieri, Thomas M

    2014-03-25

    An electronic device includes a memory configured to receive data representing light intensity values from pixels in a focal plane array and a processor that analyzes the received data to determine which light values correspond to triggered pixels, where the triggered pixels are those pixels that meet a predefined set of criteria, and determines, for each triggered pixel, a set of neighbor pixels for which light intensity values are to be stored. The electronic device also includes a buffer that temporarily stores light intensity values for at least one previously processed row of pixels, so that when a triggered pixel is identified in a current row, light intensity values for the neighbor pixels in the previously processed row and for the triggered pixel are persistently stored, as well as a data transmitter that transmits the persistently stored light intensity values for the triggered and neighbor pixels to a data receiver.

  10. Deep Moonquake Focal Mechanisms: Recovery and Implications

    NASA Technical Reports Server (NTRS)

    Weber, Renee C.; Knapmeyer, Martin

    2012-01-01

    A defining characteristic of deep moonquakes is their tendency to occur with tidal periodicity, prompting previous studies to infer that they are related to the buildup and release of tidal stress within the Moon [refs]. In studies of tidal forcing, a key constraint is the focal mechanism: the fault parameters describing the type of failure moonquakes represent. The quality of the lunar seismic data and the limited source/receiver geometries of the Apollo seismic network prohibit the determination of deep moonquake fault parameters using first-motion polarities, as is typically done in terrestrial seismology [ref]. Without being able to resolve tidal stress onto a known failure plane, we can examine only gross qualities of the tidal stress tensor with respect to moonquake occurrence, so we cannot fully address the role of tidal stress in moonquake generation.

  11. Decreased subcortical cholinergic arousal in focal seizures

    PubMed Central

    Motelow, Joshua E.; Li, Wei; Zhan, Qiong; Mishra, Asht M.; Sachdev, Robert N. S.; Liu, Geoffrey; Gummadavelli, Abhijeet; Zayyad, Zaina; Lee, Hyun Seung; Chu, Victoria; Andrews, John P.; Englot, Dario J.; Herman, Peter; Sanganahalli, Basavaraju G.; Hyder, Fahmeed; Blumenfeld, Hal

    2015-01-01

    SUMMARY Impaired consciousness in temporal lobe seizures has a major negative impact on quality of life. The prevailing view holds that this disorder impairs consciousness by seizure spread to the bilateral temporal lobes. We propose instead that seizures invade subcortical regions and depress arousal, causing impairment through decreases rather than through increases in activity. Using functional magnetic resonance imaging in a rodent model, we found increased activity in regions known to depress cortical function including lateral septum and anterior hypothalamus. Importantly, we found suppression of intralaminar thalamic and brainstem arousal systems and suppression of the cortex. At a cellular level, we found reduced firing of identified cholinergic neurons in the brainstem pedunculopontine tegmental nucleus and basal forebrain. Finally, we used enzyme-based amperometry to demonstrate reduced cholinergic neurotransmission in both cortex and thalamus. Decreased subcortical arousal is a novel mechanism for loss of consciousness in focal temporal lobe seizures. PMID:25654258

  12. Short wavelength infrared hybrid focal plane arrays

    NASA Technical Reports Server (NTRS)

    Vural, K.; Blackwell, J. D.; Marin, E. C.; Edwall, D. D.; Rode, J. P.

    1983-01-01

    The employment of area focal plane arrays (FPA) has made it possible to obtain second generation infrared imaging systems with high resolution and sensitivity. The Short Wavelength Infrared (SWIR) region (1-2.5 microns) is of importance for imaging objects at high temperature and under conditions of reflected sunlight. The present investigation is concerned with electrooptical characterization results for 32 x 32 SWIR detector arrays and FPAs which are suitable for use in a prototype imaging spectrometer. The employed detector material is Hg(1-x)Cd(x)Te grown by liquid phase epitaxy on a CdTe transparent substrate. Attention is given to details of processing, the design of the detector array, the multiplexer, the fabrication of the hybrid FPA, and aspects of performance.

  13. Infrared focal plane array crosstalk measurement

    NASA Astrophysics Data System (ADS)

    Dang, Khoa V.; Kauffman, Christopher L.; Derzko, Zenon I.

    1992-07-01

    Crosstalk between two neighboring elements in a focal plane array (FPA) occurs when signal incident on one element in the array is seen on another. This undesired effect can occur due to both the electrical and optical properties of the FPA. An effort is underway at the U.S. Army's Night Vision and Electro-Optics Directorate to develop a capability to measure crosstalk on both mid-wave infrared and long-wave infrared FPAs. A single detector in an array is illuminated using a laser source coupled with a beam expander, collimating lens, and focusing lens. The relative response of that detector to that of its neighboring detectors is measured to calculate crosstalk. The various components of the test station, the methodology for implementing the crosstalk measurement, and a model of the laser spot size are discussed.

  14. Localized LoxL3-Dependent Fibronectin Oxidation Regulates Myofiber Stretch and Integrin-Mediated Adhesion.

    PubMed

    Kraft-Sheleg, Ortal; Zaffryar-Eilot, Shelly; Genin, Olga; Yaseen, Wesal; Soueid-Baumgarten, Sharon; Kessler, Ofra; Smolkin, Tatyana; Akiri, Gal; Neufeld, Gera; Cinnamon, Yuval; Hasson, Peleg

    2016-03-01

    For muscles to function, myofibers have to stretch and anchor at the myotendinous junction (MTJ), a region rich in extracellular matrix (ECM). Integrin signaling is required for MTJ formation, and mutations affecting the cascade lead to muscular dystrophies in mice and humans. Underlying mechanisms for integrin activation at the MTJ and ECM modifications regulating its signaling are unclear. We show that lysyl oxidase-like 3 (LoxL3) is a key regulator of integrin signaling that ensures localized control of the cascade. In LoxL3 mutants, myofibers anchor prematurely or overshoot to adjacent somites, and are loose and lack tension. We find that LoxL3 complexes with and directly oxidizes Fibronectin (FN), an ECM scaffold protein and integrin ligand enriched at the MTJ. We identify a mechanism whereby localized LoxL3 secretion from myofiber termini oxidizes FN, enabling enhanced integrin activation at the tips of myofibers and ensuring correct positioning and anchoring of myofibers along the MTJ. PMID:26954549

  15. Interaction of DNA and DNA-anti-DNA complexes to fibronectin

    SciTech Connect

    Gupta, R.C.; Simpson, W.A.; Raghow, R.; Hasty, K.

    1986-03-01

    Fibronectin (Fn) is a large multidomain glycoprotein found in the basement membrane, on cell surface and in plasma. The interactions of Fn with DNA may be significant in glomerular deposition of DNA-anti-DNA complexes in patients with systemic lupus erythematosus (SLE). The authors examined the binding of DNA and DNA-anti-DNA complexes to Fn by a solid phase assay in which Fn was coated to microtiter plates and reacted with (/sup 3/H)DNA or DNA complexes with a monoclonal anti-DNA antibody. The optimal interaction of DNA with Fn occurs at <0.1M NaCl suggesting that the binding is charge dependent; the specificity of this binding was shown by competitive inhibition and locking experiments using anti-Fn. The binding was maximum at pH 6.5 and in the absence of Ca/sup 2 +/. The addition of Clq enhanced the binding of DNA and DNA-anti-DNA complexes to Fn, whereas heparan sulfate inhibited such binding. The monomeric or aggregated IgC did not bind Fn but aggregated IgG bound to Fn in the presence of Clq. Furthermore, DNA-anti-DNA complexes in sera from active SLE patients bound Fn which was enhanced in the presence of Clq; DNase abolished this binding indicating that the interaction of these complexes was mediated by DNA. These observations may partially explain the molecular mechanism(s) of the deposition of DNA-anti-DNA complexes in basement membrane.

  16. Adsorption and conformational modification of fibronectin and fibrinogen adsorbed on hydroxyapatite. A QCM-D study.

    PubMed

    Fernández-Montes Moraleda, Belén; San Román, Julio; Rodríguez-Lorenzo, Luís M

    2016-10-01

    Hydroxyapatite is a bioactive ceramic frequently used for bone engineering/replacement. One of the parameters that influence the biological response to implanted materials is the conformation of the first adsorbed protein layer. In this work, the adsorption and conformational changes of two fibroid serum proteins; fibronectin and fibrinogen adsorbed onto four different hydroxyapatite powders are studied with a Quartz Crystal Microbalance with Dissipation (QCM-D). Each of the calcined apatites adsorbs less protein than their corresponding synthesized samples. Adsorption on synthesized samples yields always an extended conformation whereas a reorganization of the layer is observed for the calcined samples. Fg acquires a "Side on" conformation in all the samples at the beginning of the experiment except for one of the synthesized samples where an "End-on" conformation is obtained during the whole experiment. The Extended conformation is the active conformation for Fn. This conformation is favored by apatites with large specific surface area (SSA) and on highly concentrated media. Apatite surface features should be considered in the selection or design of materials for bone regeneration, since it is possible to control the conformation mode of attachment of Fn and Fg by an appropriate selection of them. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2585-2594, 2016. PMID:27254464

  17. Dense Poly(ethylene glycol) Brushes Reduce Adsorption and Stabilize the Unfolded Conformation of Fibronectin.

    PubMed

    Faulón Marruecos, David; Kastantin, Mark; Schwartz, Daniel K; Kaar, Joel L

    2016-03-14

    Polymer brushes, in which polymers are end-tethered densely to a grafting surface, are commonly proposed for use as stealth coatings for various biomaterials. However, although their use has received considerable attention, a mechanistic understanding of the impact of brush properties on protein adsorption and unfolding remains elusive. We investigated the effect of the grafting density of poly(ethylene glycol) (PEG) brushes on the interactions of the brush with fibronectin (FN) using high-throughput single-molecule tracking methods, which directly measure protein adsorption and unfolding within the brush. We observed that, as grafting density increased, the rate of FN adsorption decreased; however, surface-adsorbed FN unfolded more readily, and unfolded molecules were retained on the surface for longer residence times relative to those of folded molecules. These results, which are critical for the rational design of PEG brushes, suggest that there is a critical balance between protein adsorption and conformation that underlies the utility of such brushes in physiological environments. PMID:26866385

  18. Comparison of the fibronectin-binding ability and antitumor efficacy of various mycobacteria.

    PubMed

    Hudson, M A; Ritchey, J K; Catalona, W J; Brown, E J; Ratliff, T L

    1990-07-01

    Although the mechanism by which Bacillus Calmette-Guerin (BCG) exerts an antitumor effect on superficial bladder tumors is not fully understood, recent evidence has implicated binding of BCG organisms to fibronectin (FN) as requisite for this antitumor efficacy. Various substrains of BCG and other mycobacteria were tested in vitro for their relative capacities to bind both matrix and soluble FN. A substrain of Mycobacterium kansasii, designated the "high-binding strain," was found to bind FN more readily (P less than 0.05) in in vitro studies, when compared to commercially available substrains of BCG (Tice, Connaught, and Armand Frappier). The binding by the three commercial strains of BCG to FN in vitro appeared to be equivalent. The high-binding strain was further demonstrated to attach more readily in vivo to the acutely injured murine bladder (P less than 0.005) than the Armand Frappier substrain. Finally, using the MB49 murine bladder tumor model, an enhanced antitumor effect (P less than 0.05) was noted in mice treated with intravesical high-binding strain, in comparison to the Armand Frappier substrain, during five weekly treatments. It appears not only that the commercial substrains of BCG bind FN in an equivalent manner but also that the relative binding capacities of the substrains correlate directly with antitumor activity. A substrain of M. kansasii appears to have been identified which may prove more clinically effective than the currently available strains of BCG. PMID:2191767

  19. Characterization of soluble fibronectin binding to Bacille Calmette-Guérin.

    PubMed

    Aslanzadeh, J; Brown, E J; Quillin, S P; Ritchey, J K; Ratliff, T L

    1989-10-01

    Fibronectin (FN), a 420 kDa glycoprotein, consists of two similar subunits linked by a disulphide bond near the C-terminal end. FN is present in soluble and matrix forms in various body fluids and tissues and has been shown to bind to variety of organisms. We characterized the conditions required for 125I-FN binding to Bacille Calmette-Guérin (BCG). The binding was dose-dependent, reached saturation within 3 min, and was essentially irreversible for at least 24 h under optimal binding conditions at pH 6.0. In contrast, the binding was reversible (greater than 90% in 24 h) when the pH was increased to 10.0. Scatchard analysis of the dose-response experiments produced a straight line, suggesting the presence of a single class of FN receptor on BCG. 125I-FN binding was trypsin-sensitive, suggesting that the BCG-binding molecule is a protein. The number of FN receptors was determined to be 8000-15,000 per bacterium. 125I-FN binding was pH dependent, with maximal binding at acidic pH. 125I-FN binding was sensitive to the presence of NaCl, with 0.08 M-NaCl inhibiting binding by 85%. These data demonstrate that soluble FN binds to a trypsin-sensitive cell-surface component of BCG in an essentially irreversible manner. PMID:2534398

  20. Role of fibronectin in intravesical BCG therapy for superficial bladder cancer.

    PubMed

    Ratliff, T L; Kavoussi, L R; Catalona, W J

    1988-02-01

    Intravesical bacillus Calmette-Guerin (BCG) has been demonstrated to be effective both for prophylaxis and treatment of superficial bladder cancer. In order to identify the progression of events that result in BCG-mediated antitumor activity, studies were performed to evaluate the mechanism of binding of BCG within the bladder. Histological and quantitative studies in a mouse model revealed that BCG attached to the bladder wall only in areas of urothelial damage. Preliminary in vitro data showed that BCG attached to surfaces coated with extracellular matrix proteins. Further studies were then performed using purified extracellular matrix proteins to identify the proteins responsible for attachment. BCG were observed to attach to surfaces coated only with purified fibronectin (FN) but not to other purified proteins including laminin, collagen or fibrinogen. The attachment of BCG to purified FN in vitro was dose dependent and was inhibited by anti-FN antibodies. Moreover, BCG attachment in vivo to bladders with damaged urothelial surfaces was inhibited more than 95% by anti-FN antibodies, but binding was not affected by anti-laminin antibodies or preimmune serum. A survey of commercially available BCG vaccines (Pasteur, Tice, Glaxo, Connaught) showed that only Glaxo BCG did not attach to FN-coated surfaces. Glaxo BCG also was shown to express inferior antitumor activity suggesting that the absence of FN binding by Glaxo may have been associated with the absence of antitumor activity of the vaccine. PMID:3276931

  1. Fibronectin adsorption on osteoconductive hydroxyapatite and non-osteoconductive α-alumina.

    PubMed

    Hasegawa, Maki; Kudo, Tada-Aki; Kanetaka, Hiroyasu; Miyazaki, Toshiki; Hashimoto, Masami; Kawashita, Masakazu

    2016-01-01

    The osteoconductivity mechanism of hydroxyapatite (HAp) has not been elucidated. It is hypothesized that specific proteins adsorb on HAp, promoting its osteoconductivity. To verify this hypothesis, we compared the adsorption behavior of fibronectin (Fn) on HAp powder and on α-alumina (α-Al2O3) powder, a material with no osteoconductivity. More Fn adsorbed on α-Al2O3 than on HAp, irrespective of the Fn concentration, and there was no significant difference in the secondary structure of Fn adsorbed on HAp and α-Al2O3. Further, it is possible that Fn did not adsorb on HAp and α-Al2O3 through the Arg-Gry-Asp motif of Fn. The amount of Fn adsorbed on HAp oriented to the a(b)-axis with very little decrease in carbonate and the adsorbed Fn had a smaller α-helix structure content. The results suggest that the secondary and/or higher-order structure rather than the amount of adsorbed Fn might affect the osteoconductivity of HAp, which might be electrostatically controlled by the crystal face orientation and/or carbonate content of HAp, although this should be confirmed by a cell culture test in the future. PMID:27509476

  2. Mechanical forces regulate the interactions of fibronectin and collagen I in extracellular matrix

    PubMed Central

    Kubow, Kristopher E.; Vukmirovic, Radmila; Zhe, Lin; Klotzsch, Enrico; Smith, Michael L.; Gourdon, Delphine; Luna, Sheila; Vogel, Viola

    2015-01-01

    Despite the crucial role of extracellular matrix (ECM) in directing cell fate in healthy and diseased tissues—particularly in development, wound healing, tissue regeneration and cancer—the mechanisms that direct the assembly and regulate hierarchical architectures of ECM are poorly understood. Collagen I matrix assembly in vivo requires active fibronectin (Fn) fibrillogenesis by cells. Here we exploit Fn-FRET probes as mechanical strain sensors and demonstrate that collagen I fibres preferentially co-localize with more-relaxed Fn fibrils in the ECM of fibroblasts in cell culture. Fibre stretch-assay studies reveal that collagen I's Fn-binding domain is responsible for the mechano-regulated interaction. Furthermore, we show that Fn-collagen interactions are reciprocal: relaxed Fn fibrils act as multivalent templates for collagen assembly, but once assembled, collagen fibres shield Fn fibres from being stretched by cellular traction forces. Thus, in addition to the well-recognized, force-regulated, cell-matrix interactions, forces also tune the interactions between different structural ECM components. PMID:26272817

  3. Three-dimensional culture regulates Raf-1 expression to modulate fibronectin matrix assembly.

    PubMed

    Winters, B S; Raj, B K Mohan; Robinson, E E; Foty, R A; Corbett, S A

    2006-08-01

    Oncogenic transformation has been associated with decreased fibronectin (FN) matrix assembly. For example, both the HT-1080 fibrosarcoma and MAT-LyLu cell lines fail to assemble a FN matrix when grown in monolayer culture (2-dimensional [2D] system). In this study, we show that these cells regain the ability to assemble a FN matrix when they are grown as aggregates (3-dimensional [3D] system). FN matrix assembly in 3D correlates with decreased Raf-1 protein expression compared with cells grown in monolayer culture. This effect is associated with reduced Raf-1 mRNA levels as determined by quantitative RT-PCR and not proteasome-mediated degradation of endogenous Raf-1. Interestingly, transient expression of a Raf-1 promoter-reporter construct demonstrates increased Raf-1 promoter activity in 3D, suggesting that the transition to 3D culture may modulate Raf-1 mRNA stability. Finally, to confirm that decreased Raf-1 expression results in increased FN matrix assembly, we used both pharmacological and small interfering RNA knockdown of Raf-1. This restored the ability of cells in 2D culture to assemble a FN matrix. Moreover, overexpression of Raf-1 prevented FN matrix assembly by cells cultured in 3D, resulting in decreased aggregate compaction. This work provides new insight into how the cell microenvironment may influence Raf-1 expression to modulate cell-FN interactions in 3D. PMID:16707572

  4. Fibronectin is Essential for Reparative Cardiac Progenitor Cell Response Following Myocardial Infarction

    PubMed Central

    Konstandin, Mathias H.; Toko, Haruhiro; Gastelum, Grady M.; Quijada, Pearl; De La Torre, Andrea; Quintana, Mercedes; Collins, Brett; Din, Shabana; Avitabile, Daniele; Völkers, Mirko; Gude, Natalie; Fässler, Reinhard; Sussman, Mark A.

    2013-01-01

    Rationale Adoptive transfer of cardiac progenitor cells (CPCs) has entered clinical application despite limited mechanistic understanding of the endogenous response following myocardial infarction (MI). Extracellular matrix (ECM) undergoes dramatic changes after MI and therefore might be linked to CPC-mediated repair. Objective Demonstrate the significance of Fibronectin (Fn), a component of the ECM, for induction of the endogenous CPC response to MI. Methods and Results This report shows that presence of CPCs correlates with expression of Fn during cardiac development and after MI. In vivo, genetic conditional ablation of Fn blunts CPC response measured 7 days after MI through reduced proliferation and diminished survival. Attenuated vasculogenesis and cardiogenesis during recovery was evident at the end of a 12 week follow-up period. Impaired CPC-dependent reparative remodeling ultimately leads to continuous decline of cardiac function in Fn knockout animals. In vitro, Fn protects and induces proliferation of CPCs via β1-Integrin-FAK-Stat3-Pim1 but Akt-independent mechanism. Conclusion Fn is essential for endogenous CPC expansion and repair needed for stabilization of cardiac function after MI. PMID:23652800

  5. Fibronectin promotes differentiation of neural crest progenitors endowed with smooth muscle cell potential

    SciTech Connect

    Costa-Silva, Bruno; Coelho da Costa, Meline; Melo, Fernanda Rosene; Neves, Cynara Mendes; Alvarez-Silva, Marcio; Calloni, Giordano Wosgrau; Trentin, Andrea Goncalves

    2009-04-01

    The neural crest (NC) is a model system used to investigate multipotency during vertebrate development. Environmental factors control NC cell fate decisions. Despite the well-known influence of extracellular matrix molecules in NC cell migration, the issue of whether they also influence NC cell differentiation has not been addressed at the single cell level. By analyzing mass and clonal cultures of mouse cephalic and quail trunk NC cells, we show for the first time that fibronectin (FN) promotes differentiation into the smooth muscle cell phenotype without affecting differentiation into glia, neurons, and melanocytes. Time course analysis indicated that the FN-induced effect was not related to massive cell death or proliferation of smooth muscle cells. Finally, by comparing clonal cultures of quail trunk NC cells grown on FN and collagen type IV (CLIV), we found that FN strongly increased both NC cell survival and the proportion of unipotent and oligopotent NC progenitors endowed with smooth muscle potential. In contrast, melanocytic progenitors were prominent in clonogenic NC cells grown on CLIV. Taken together, these results show that FN promotes NC cell differentiation along the smooth muscle lineage, and therefore plays an important role in fate decisions of NC progenitor cells.

  6. Adipose progenitor cells increase fibronectin matrix strain and unfolding in breast tumors

    NASA Astrophysics Data System (ADS)

    Chandler, E. M.; Saunders, M. P.; Yoon, C. J.; Gourdon, D.; Fischbach, C.

    2011-02-01

    Increased stiffness represents a hallmark of breast cancer that has been attributed to the altered physicochemical properties of the extracellular matrix (ECM). However, the role of fibronectin (Fn) in modulating the composition and mechanical properties of the tumor-associated ECM remains unclear. We have utilized a combination of biochemical and physical science tools to evaluate whether paracrine signaling between breast cancer cells and adipose progenitor cells regulates Fn matrix assembly and stiffness enhancement in the tumor stroma. In particular, we utilized fluorescence resonance energy transfer imaging to map the molecular conformation and stiffness of Fn that has been assembled by 3T3-L1 preadipocytes in response to conditioned media from MDA-MB231 breast cancer cells. Our results reveal that soluble factors secreted by tumor cells promote Fn expression, unfolding, and stiffening by adipose progenitor cells and that transforming growth factor-β serves as a soluble cue underlying these changes. In vivo experiments using orthotopic co-transplantation of primary human adipose-derived stem cells and MDA-MB231 into SCID mice support the pathological relevance of our results. Insights gained by these studies advance our understanding of the role of Fn in mammary tumorigenesis and may ultimately lead to improved anti-cancer therapies.

  7. Regulation of Fibronectin EDA Exon Alternative Splicing: Possible Role of RNA Secondary Structure for Enhancer Display

    PubMed Central

    Muro, Andrés F.; Caputi, Massimo; Pariyarath, Rajalakshmi; Pagani, Franco; Buratti, Emanuele; Baralle, Francisco E.

    1999-01-01

    The fibronectin primary transcript undergoes alternative splicing in three noncoordinated sites: the cassette-type EDA and EDB exons and the more complex IIICS region. We have shown previously that an 81-nucleotide region within the EDA exon is necessary for exon recognition and that this region contains at least two splicing-regulatory elements: a polypurinic enhancer (exonic splicing enhancer [ESE]) and a nearby silencer element (exonic splicing silencer [ESS]). Here, we have analyzed the function of both elements in different cell types. We have mapped the ESS to the nucleotide level, showing that a single base change is sufficient to abolish its function. Testing of the ESE and ESS elements in heterologous exons, individually or as part of the complete EDA regulatory region, showed that only the ESE element is active in different contexts. Functional studies coupled to secondary-structure enzymatic analysis of the EDA exon sequence variants suggest that the role of the ESS element may be exclusively to ensure the proper RNA conformation and raise the possibility that the display of the ESE element in a loop position may represent a significant feature of the exon splicing-regulatory region. PMID:10082532

  8. Absence of regulated splicing of fibronectin EDA exon reduces atherosclerosis in mice

    PubMed Central

    Babaev, Vladimir R.; Porro, Fabiola; Linton, MacRae F.; Fazio, Sergio; Baralle, Francisco E.; Muro, Andrés F.

    2008-01-01

    Atherosclerotic lesions are characterized by a profound alteration in the architecture of the arterial intima, with a marked increase of fibronectin (FN) and the appearance of the alternatively spliced FN variant containing the Extra Domain A (EDA). To analyze the role of FN isoforms in atherosclerotic lesion formation we utilized mouse strains devoid of EDA-exon regulated splicing, which constitutively include (EDA+/+) or exclude (EDA−/−) the exon. Both mutant mice had a 40% reduction in atherosclerotic lesions after the atherogenic-diet treatment (Mean±SE, μm2; 22969±2185; 13660±1533; 14260±2501 for EDAwt/wt, EDA+/+ and EDA−/−, respectively; p≤0.01 ANOVA test) associated to a lower capacity of macrophages to uptake modified LDL and undergo foam-cell formation. Lesions in control mice were more numerous and bigger, with augmented and deeper macrophage infiltration, and increased FN expression in the sub-endothelial area. Previous experiments have shown that apoE−/−EDA−/− mice have a decreased number and size of atherosclerotic lesions and, on this basis, it has been proposed that the EDA domain has a pro-atherogenic role. Our data with the EDA+/+ mice rules out this hypothesis and suggest that regulated splicing of the EDA exon of the FN gene is involved in progression of atherosclerosis, highlighting the importance of alternative splicing in regulating cellular processes. PMID:17897651

  9. Hepatitis B Virus Stimulated Fibronectin Facilitates Viral Maintenance and Replication through Two Distinct Mechanisms

    PubMed Central

    Ren, Sheng; Wang, Jun; Chen, Tie-Long; Li, Hao-Yu; Wan, Yu-Shun; Peng, Nan-Fang; Gui, Xi-En; Zhu, Ying

    2016-01-01

    Fibronectin (FN) is a high molecular weight extracellular matrix protein that functions in cell adhesion, growth, migration, and embryonic development. However, little is known about the role of FN during viral infection. In the present study, we found significantly higher levels of FN in sera, and liver tissues from hepatitis B virus (HBV) patients relative to healthy individuals. HBV expression enhanced FN mRNA and protein levels in the hepatic cell lines Huh7 and HepG2. HBV infection of susceptible HepG2-sodium taurocholate co-transporting polypeptide cells also increased FN expression. We also found that transcriptional factor specificity protein 1 was involved in the induction of FN by HBV. Knockdown of FN expression significantly inhibited HBV DNA replication and protein synthesis through activating endogenous IFN-α production. In addition, FN interacted with the transforming growth factor β-activated protein kinase 1 (TAK1) and TAK1-binding protein complex and attenuated interferon signaling by inhibiting TAK1 phosphorylation. Furthermore, the nuclear translocation of NF-κB/p65 was found to be inhibited by FN. We also observed that FN promoted HBV enhancers to support HBV expression. These results suggest novel functions of endogenous FN involved in immune evasion and maintenance of HBV replication. PMID:27023403

  10. Biocompatibility and Favorable Response of Mesenchymal Stem Cells on Fibronectin-Gold Nanocomposites

    PubMed Central

    Hung, Huey-Shan; Tang, Cheng-Ming; Lin, Chien-Hsun; Lin, Shinn-Zong; Chu, Mei-Yun; Sun, Wei-Shen; Kao, Wei-Chien; Hsien-Hsu, Hsieh

    2013-01-01

    A simple surface modification method, comprising of a thin coating with gold nanoparticles (AuNPs) and fibronectin (FN), was developed to improve the biocompatibility required for cardiovascular devices. The nanocomposites from FN and AuNPs (FN-Au) were characterized by the atomic force microscopy (AFM), UV-Vis spectrophotometry (UV-Vis), and Fourier transform infrared spectroscopy (FTIR). The biocompatibility of the nanocomposites was evaluated by the response of monocytes and platelets to the material surface in vitro. FN-Au coated surfaces demonstrated low monocyte activation and platelet activation. The behavior of human umbilical cord-derived mesenchymal stem cells (MSCs) on FN-Au was further investigated. MSCs on FN-Au nanocomposites particularly that containing 43.5 ppm of AuNPs (FN-Au 43.5 ppm) showed cell proliferation, low ROS generation, as well as increases in the protein expression levels of matrix metalloproteinase-9 (MMP-9) and endothelial nitric oxide synthase (eNOS), which may account for the enhanced MSC migration on the nanocomposites. These results suggest that the FN-Au nanocomposite thin film coating may serve as a potential and simple solution for the surface modification of blood-contacting devices such as vascular grafts. PMID:23826082

  11. Simple coating with fibronectin fragment enhances stainless steel screw osseointegration in healthy and osteoporotic rats.

    PubMed

    Agarwal, Rachit; González-García, Cristina; Torstrick, Brennan; Guldberg, Robert E; Salmerón-Sánchez, Manuel; García, Andrés J

    2015-09-01

    Metal implants are widely used to provide structural support and stability in current surgical treatments for bone fractures, spinal fusions, and joint arthroplasties as well as craniofacial and dental applications. Early implant-bone mechanical fixation is an important requirement for the successful performance of such implants. However, adequate osseointegration has been difficult to achieve especially in challenging disease states like osteoporosis due to reduced bone mass and strength. Here, we present a simple coating strategy based on passive adsorption of FN7-10, a recombinant fragment of human fibronectin encompassing the major cell adhesive, integrin-binding site, onto 316-grade stainless steel (SS). FN7-10 coating on SS surfaces promoted α5β1 integrin-dependent adhesion and osteogenic differentiation of human mesenchymal stem cells. FN7-10-coated SS screws increased bone-implant mechanical fixation compared to uncoated screws by 30% and 45% at 1 and 3 months, respectively, in healthy rats. Importantly, FN7-10 coating significantly enhanced bone-screw fixation by 57% and 32% at 1 and 3 months, respectively, and bone-implant ingrowth by 30% at 3 months compared to uncoated screws in osteoporotic rats. These coatings are easy to apply intra-operatively, even to implants with complex geometries and structures, facilitating the potential for rapid translation to clinical settings. PMID:26100343

  12. Effect of fibronectin adsorption on osteoblastic cellular responses to hydroxyapatite and alumina.

    PubMed

    Kawashita, Masakazu; Hasegawa, Maki; Kudo, Tada-Aki; Kanetaka, Hiroyasu; Miyazaki, Toshiki; Hashimoto, Masami

    2016-12-01

    Initial cellular responses following implantation are important for inducing osteoconduction. We investigated cell adhesion, spreading, proliferation and differentiation of mouse MC3T3-E1 osteoblastic cells on untreated or fibronectin (Fn)-coated discs of hydroxyapatite (HAp) or alpha-type alumina (α-Al2O3). Fn coating significantly enhanced adhesion and spreading of MC3T3-E1 cells on HAp, but did not affect MC3T3-E1 cell proliferation and differentiation on HAp or α-Al2O3. Fn-coated HAp likely does not stimulate pre-osteoblast cells to initiate the process of osteoconduction; however, Fn adsorption might affect the response of inflammatory cells to the implanted material or, in conjunction with other serum proteins, stimulate pre-osteoblast cell proliferation and differentiation. Further studies on the effect of serum proteins in cell culture and the efficacy of Fn-coated HAp and α-Al2O3in vivo are warranted. PMID:27612826

  13. Fibronectin and the adhesive properties of rat lymphocytes obtained from different peripheral lymphoid tissues.

    PubMed

    Altankov, G; Kostadinov, A; Marinova, L

    1990-01-01

    A comparative investigation has been carried out on the effect of plasma fibronectin (Fn) on the adhesive properties of normal rat lymphocytes obtained from different lymphoid tissues: blood, spleen, mesenteric and tonsillar lymph nodes. Fn was immobilized on the basis of its ability to bind to gelatin. We established that concentrations of 40-50 micrograms/ml are sufficient for a saturation effect on Fn coating. For spleen cells an adhesion of 55.7 +/- 9.3%, for mesenteric lymph nodes 34.5 +/- 8.7% and for tonsillar cells 33.8 +/- 3.2% was observed. Blood lymphocytes showed the lowest adhesion, 21.3 +/- 4.2%. Compared to the other lymphoid tissues, the spleen cells exhibited a "basal" adherence to surfaces coated with gelatin only: 19.2 +/- 4.1%. T lymphocytes participate to a greater extent in the process, since their number was significantly reduced in cell suspensions after adhesion to both gelatin and gelatin-Fn coated surfaces. The addition of soluble Fn leads to a competitive inhibition of the lymphocyte adhesion to gelatin-Fn coated surfaces. The data demonstrated the important role of Fn for the adhesive interactions of lymphocytes during their functional distribution in the tissues. PMID:2076848

  14. Recombinant expression and characterization of a novel fibronectin isoform expressed in cartilaginous tissues.

    PubMed

    Kozaki, Tomohiro; Matsui, Yoshito; Gu, Jianguo; Nishiuchi, Ryoko; Sugiura, Nobuo; Kimata, Koji; Ozono, Keiichi; Yoshikawa, Hideki; Sekiguchi, Kiyotoshi

    2003-12-12

    A novel fibronectin (FN) isoform lacking the segment from IIICS (type III connecting segment) through the I-10 module is expressed predominantly in normal cartilaginous tissues. We expressed and purified recombinant cartilage-type FN using a mammalian expression system and characterized its molecular and biological properties. Although FNs have been shown to be secreted as disulfide-bonded dimers, cartilage-type FN was secreted mainly as a monomer. It was less potent than plasma-type FN in promoting cell adhesion and binding to integrin alpha5beta1, although it was more active than plasma-type FN in binding to chondroitin sulfate E. When added exogenously, cartilage-type FN was poorly assembled into the fibrillar FN matrix, mostly because of its monomeric structure. Given that cartilage is characterized by its non-fibrillar matrix with abundant chondroitin sulfate-containing proteoglycans, it is likely that cartilage-type FN has evolved to adapt itself to the non-fibrillar structure of the cartilage matrix through acquisition of a novel mechanism of alternative pre-mRNA splicing. PMID:14525997

  15. Altered ECM deposition by diabetic foot ulcer-derived fibroblasts implicates fibronectin in chronic wound repair.

    PubMed

    Maione, Anna G; Smith, Avi; Kashpur, Olga; Yanez, Vanessa; Knight, Elana; Mooney, David J; Veves, Aristidis; Tomic-Canic, Marjana; Garlick, Jonathan A

    2016-07-01

    Current chronic wound treatments often fail to promote healing of diabetic foot ulcers (DFU), leading to amputation and increased patient morbidity. A critical mediator of proper wound healing is the production, assembly, and remodeling of the extracellular matrix (ECM) by fibroblasts. However, little is known about how these processes are altered in fibroblasts within the DFU microenvironment. Thus, we investigated the capacity of multiple, primary DFU-derived fibroblast strains to express, produce, and assemble ECM proteins compared to diabetic patient-derived fibroblasts and healthy donor-derived fibroblasts. Gene expression microarray analysis showed differential expression of ECM and ECM-regulatory genes by DFU-derived fibroblasts which translated to functional differences in a 3D in vitro ECM tissue model. DFU-derived fibroblasts produced thin, fibronectin-rich matrices, and responded abnormally when challenged with transforming growth factor-beta, a key regulator of matrix production during healing. These results provide novel evidence that DFU-derived fibroblasts contribute to the defective matrices of DFUs and chronic wound pathogenesis. PMID:27102877

  16. Guiding Epithelial Cell Phenotypes with Engineered Integrin-Specific Recombinant Fibronectin Fragments

    PubMed Central

    Brown, Ashley C.; Rowe, Jessica A.

    2011-01-01

    The extracellular matrix (ECM) provides important cues for directing cell phenotype. Cells interact with underlying ECM through cell-surface receptors known as integrins, which bind to specific sequences on their ligands. During tissue development, repair, and regeneration of epithelial tissues, cells must interact with an interstitial fibronectin (Fn)-rich matrix, which has been shown to direct a more migratory/repair phenotype, presumably through interaction with Fn’s cell binding domain comprised of both synergy Pro-His-Ser-Arg-Asn (PHSRN) and Arg-Gly-Asp (RGD) sequences. We hypothesized that the Fn synergy site is critical to the regulation of epithelial cell phenotype by directing integrin specificity. Epithelial cells were cultured on Fn fragments displaying stabilized synergy and RGD (FnIII9’10), or RGD alone (FnIII10) and cell phenotype analyzed by cytoskeleton changes, epithelial cell–cell contacts, changes in gene expression of epithelial and mesenchymal markers, and wound healing assay. Data indicate that epithelial cells engage RGD only with αv integrins and display a significant shift toward a mesenchymal phenotype due, in part, to enhanced transforming growth factor-β activation and/or signaling compared with cells on the synergy containing FnIII9’10. These studies demonstrate the importance of synergy in regulating epithelial cell phenotype relevant to tissue engineering as well as the utility of engineered integrin-specific ECM fragments in guiding cell phenotype. PMID:20695776

  17. Treatment of gingival recession using free gingival graft with fibrin fibronectin sealing system: A novel approach.

    PubMed

    Srinivas, B V V; Rupa, N; Halini Kumari, K V; Rajender, A; Reddy, M Narendra

    2015-08-01

    Periodontal plastic surgery is the branch of periodontology that is focused mainly on the correction or elimination of mucogingival problems associated with lack of attached gingiva, a shallow vestibule and aberrant frenum. Various mucogingival surgical procedures are used to halt the progression of the gingival recession and to correct poor esthetic appearance. Free gingival autograft is one of the most common techniques used for a gingival recession in areas of inadequate attached gingiva in the mandibular anterior region. Fibrin sealants are human plasma derivatives that mimic the final stages of blood coagulation, forming a fibrin clot. Fibrin Sealants enhances the overall outcome of surgical intervention because of their hemostatic, adhesive, and healing properties. These properties of fibrin sealants may reduce operating time, prevent complications, and enhance the overall outcome of many surgical interventions. Hence, this case report aims to investigate the clinical effectiveness of free gingival graft along with the commercially available fibrin-fibronectin sealing system (Tissucol(®)) in the treatment of Miller's class II gingival recession. PMID:26538956

  18. Fibronectin Interaction and Enhancement of Growth Factors: Importance for Wound Healing

    PubMed Central

    Sawicka, Katarzyna M.; Seeliger, Markus; Musaev, Tagai; Macri, Lauren K.; Clark, Richard A.F.

    2015-01-01

    Significance: This critical review focuses on interactions between cells, fibronectin (FN), and growth factors (GF). Recent Advances: Initially, the extracellular matrix (ECM) was thought to serve simply as a reservoir for GFs that would be released as soluble ligands during proteolytic degradation of ECM. This view was rather quickly extended by the observation that ECM could concentrate GFs to the pericellular matrix for more efficient presentation to cell surface receptors. However, recent reports support much more complex interactions among GFs and ECM molecules, particularly FN, and the way these interactions can fine-tune cell responses to the microenvironment. Critical Issues: Wounds that are unable to synthesize and sustain a functional ECM cannot optimally benefit from endogenous or exogenous GFs. Therefore, GF treatments have recently focused on utilizing ECM molecules as delivery vehicles. Thus, ECM can influence GF stability and activity, and GFs can modulate the ECM activity. Hence, both individually and together, ECM and GFs modulate cells that in turn control the type and level of GFs and ECM in the pericellular environment that ultimately results in new tissue generation. Although many ECM components are important for optimal tissue regeneration and wound healing, FN stands out as absolutely critical not only for wound healing and tissue regeneration but also for embryogenesis and morphogenesis. Future Directions: Understanding ECM/GF interactions will greatly facilitate our understanding of normal wound repair and regeneration, the failure of wounds to heal, and how the latter can be salvaged with proper ECM/GF combinations. PMID:26244103

  19. Neutrophil elastase and fetal fibronectin levels as predictors of single-birth prematurity

    PubMed Central

    AI, FANG; LI, GUI-QING; JIANG, JIANG; DONG, XU-DONG

    2015-01-01

    The aim of this study was to investigate the predictive values (PVs) of neutrophil elastase (NE) and fetal fibronectin (fFN) in cervical secretions for single-birth premature delivery. Samples of cervical secretions were obtained from 144 women with high-risk singleton pregnancies at 20–34 weeks' gestation and premature Creasy scores of >12 points for NE and fFN level testing, and the PVs of the two indicators for premature birth (PB) were retrospectively analyzed. NE and fFN had high negative PVs (NPVs) for PB; the NPV of NE and fFN for delivery 7 days after detection was significantly higher than the positive PV (P<0.01). In addition, the sensitivity of the combined use of NE and fFN levels for PB prediction was high if both were present, and the PB rate of the double-positive group was higher than that of the single-positive group (P<0.01). Clinical intervention could turn the NE and fFN values negative in certain cases; in these cases, the PB rate was significantly lower than that in the sustained-positive group. In conclusion, NE and fFN in cervical secretions could be used as objective predictors of premature delivery, and their combined application could improve the prediction sensitivity. Effective clinical intervention could then reduce the incidence of PB. PMID:26622372

  20. Migration of lymphocytes on fibronectin-coated surfaces: temporal evolution of migratory parameters

    NASA Technical Reports Server (NTRS)

    Bergman, A. J.; Zygourakis, K.; McIntire, L. V. (Principal Investigator)

    1999-01-01

    Lymphocytes typically interact with implanted biomaterials through adsorbed exogenous proteins. To provide a more complete characterization of these interactions, analysis of lymphocyte migration on adsorbed extracellular matrix proteins must accompany the commonly performed adhesion studies. We report here a comparison of the migratory and adhesion behavior of Jurkat cells (a T lymphoblastoid cell line) on tissue culture treated and untreated polystyrene surfaces coated with various concentrations of fibronectin. The average speed of cell locomotion showed a biphasic response to substrate adhesiveness for cells migrating on untreated polystyrene and a monotonic decrease for cells migrating on tissue culture-treated polystyrene. A modified approach to the persistent random walk model was implemented to determine the time dependence of cell migration parameters. The random motility coefficient showed significant increases with time when cells migrated on tissue culture-treated polystyrene surfaces, while it remained relatively constant for experiments with untreated polystyrene plates. Finally, a cell migration computer model was developed to verify our modified persistent random walk analysis. Simulation results suggest that our experimental data were consistent with temporally increasing random motility coefficients.

  1. Neuropilin-1 stimulates tumor growth by increasing fibronectin fibril assembly in the tumor microenvironment

    PubMed Central

    Yaqoob, Usman; Cao, Sheng; Shergill, Uday; Jagavelu, Kumaravelu; Geng, Zhimin; Yin, Meng; de Assuncao, Thiago M; Cao, Ying; Szabolcs, Anna; Thorgeirsson, Snorri; Schwartz, Martin; Yang, Ju Dong; Ehman, Richard; Roberts, Lewis; Mukhopadhyay, Debabrata; Shah, Vijay H.

    2012-01-01

    The tumor microenvironment, including stromal myofibroblasts and associated matrix proteins, regulates cancer cell invasion and proliferation. Here we report that neuropilin-1 (NRP-1) orchestrates communications between myofibroblasts and soluble fibronectin (FN) that promote α5β1 integrin-dependent FN fibril assembly, matrix stiffness, and tumor growth. Tumor growth and FN fibril assembly was reduced by genetic depletion or antibody neutralization of NRP-1 from stromal myofibroblasts in vivo. Mechanistically, the increase in FN fibril assembly required glycosylation of serine 612 of the extracellular domain of NRP-1, an intact intracellular NRP-1 SEA domain, and intracellular associations between NRP-1, the scaffold protein GIPC, and the nonreceptor tyrosine kinase c-Abl, that augmented α5β1 FN fibril assembly activity. Analysis of human cancer specimens established an association between tumoral NRP-1 levels and clinical outcome. Our findings indicate that NRP-1 activates the tumor microenvironment, thereby promoting tumor growth. These results not only identify new molecular mechanisms of FN fibril assembly but also have important implications for therapeutic targeting of the myofibroblast in the tumor microenvironment. PMID:22738912

  2. Revealing the dependence of cell spreading kinetics on its spreading morphology using microcontact printed fibronectin patterns

    PubMed Central

    Huang, Cheng-Kuang; Donald, Athene

    2015-01-01

    Since the dawn of in vitro cell cultures, how cells interact and proliferate within a given external environment has always been an important issue in the study of cell biology. It is now well known that mammalian cells typically exhibit a three-phase sigmoid spreading on encountering a substrate. To further this understanding, we examined the influence of cell shape towards the second rapid expansion phase of spreading. Specifically, 3T3 fibroblasts were seeded onto silicon elastomer films made from polydimethylsiloxane (PDMS), and micro-contact printed with fibronectin stripes of various dimensions. PDMS is adopted in our study for its biocompatibility, its ease in producing very smooth surfaces, and in the fabrication of micro-contact printing stamps. The substrate patterns are compared with respect to their influence on cell spreading over time. Our studies reveal, during the early rapid expansion phase, 3T3 fibroblasts are found to spread radially following a law; meanwhile, they proliferated in a lengthwise fashion on the striped patterns, following a law. We account for the observed differences in kinetics through a simple geometric analysis which predicted similar trends. In particular, a t2 law for radial spreading cells, and a t1 law for lengthwise spreading cells. PMID:25551146

  3. Exploring cell compatibility of a fibronectin-functionalized physically crosslinked poly(vinyl alcohol) hydrogel.

    PubMed

    Millon, Leonardo E; Padavan, Donna T; Hamilton, Amanda M; Boughner, Derek R; Wan, Wankei

    2012-01-01

    Physically crosslinked poly(vinyl alcohol) (PVA) hydrogels prepared using a low-temperature thermally cycled process have tunable mechanical properties that fall within the range of soft tissues, including cardiovascular tissue. An approach to render it hemocompatible is by endothelization, but its hydrophilic nature is not conducive to cell adhesion and spreading. We investigated the functionalization reaction of this class of PVA hydrogel with fibronectin (FN) for adhesion and spreading of primary porcine radial artery cells and vascular endothelial cells. These are cells relevant to small-diameter vascular graft development. FN functionalization was achieved using a multistep reaction, but the activation step involving carbonyl diimidazole normally required for chemically crosslinked PVA was found to be unnecessary. The reaction resulted in an increase in the elastic modulus of the PVA hydrogel but is still well within the range of cardiovascular tissue. Confocal microscopy confirmed the adhesion and spreading of both cell types on the PVA-FN surfaces, whereas cells failed to adhere to the PVA control. This is a first step toward an alternative for the realization of a synthetic replacement small-diameter vascular graft. PMID:21998037

  4. Focal cortical dysplasias in autism spectrum disorders

    PubMed Central

    2013-01-01

    Background Previous reports indicate the presence of histological abnormalities in the brains of individuals with autism spectrum disorders (ASD) suggestive of a dysplastic process. In this study we identified areas of abnormal cortical thinning within the cerebral cortex of ASD individuals and examined the same for neuronal morphometric abnormalities by using computerized image analysis. Results The study analyzed celloidin-embedded and Nissl-stained serial full coronal brain sections of 7 autistic (ADI-R diagnosed) and 7 age/sex-matched neurotypicals. Sections were scanned and manually segmented before implementing an algorithm using Laplace’s equation to measure cortical width. Identified areas were then subjected to analysis for neuronal morphometry. Results of our study indicate the presence within our ASD population of circumscribed foci of diminished cortical width that varied among affected individuals both in terms of location and overall size with the frontal lobes being particularly involved. Spatial statistic indicated a reduction in size of neurons within affected areas. Granulometry confirmed the presence of smaller pyramidal cells and suggested a concomitant reduction in the total number of interneurons. Conclusions The neuropathology is consistent with a diagnosis of focal cortical dysplasia (FCD). Results from the medical literature (e.g., heterotopias) and our own study suggest that the genesis of this cortical malformation seemingly resides in the heterochronic divisions of periventricular germinal cells. The end result is that during corticogenesis radially migrating neuroblasts (future pyramidal cells) are desynchronized in their development from those that follow a tangential route (interneurons). The possible presence of a pathological mechanism in common among different conditions expressing an autism-like phenotype argue in favor of considering ASD a “sequence” rather than a syndrome. Focal cortical dysplasias in ASD may serve to

  5. Focal symmetrical encephalomalacia in a goat.

    PubMed

    Oliveira, Diego M; Pimentel, Luciano A; Pessoa, André F; Dantas, Antônio F M; Uzal, Francisco; Riet-Correa, Franklin

    2010-09-01

    Focal symmetrical encephalomalacia (FSE) is the most prominent lesion seen in the chronic form of enterotoxemia caused by Clostridium perfringens type D in sheep. However, this lesion has not been reported in goats. The current paper reports a case of FSE in a goat from the state of Paraíba in the Brazilian semiarid region. As reported by the farmer, 30, 4-48-month-old animals from a flock of 150 goats died after showing nervous signs, including blindness and recumbence, for periods varying between 1 and 14 days. The flock was grazing native pasture supplemented with wheat and corn bran. Additionally, lactating goats were supplemented with soybeans. A 4-month-old goat with nervous signs was examined clinically and then necropsied 3 days after the onset of clinical signs. Bilateral, focal, and symmetrical areas of brown discoloration were observed in the internal capsule and thalamus. Histologic lesions in these areas consisted of multifocal, bilateral malacia with a few neutrophils; endothelial cell swelling; perivascular edema; and hemorrhages. The etiology of these lesions was not determined. However, FSE is considered pathognomonic for C. perfringens type D enterotoxemia in sheep, and it is speculated that this microorganism was the etiologic agent in the present case. The flock had been vaccinated against type D enterotoxemia only once, approximately 3 months before the beginning of the outbreak. Insufficient immunity due to the incorrect vaccination protocol, low efficacy of the vaccine used, and a diet including large amounts of highly fermentable carbohydrates were suspected to be predisposing factors for this outbreak. PMID:20807946

  6. Dementia and driving

    MedlinePlus

    ... getting more dangerous include: Getting lost on familiar roads Reacting more slowly in traffic Driving too slowly ... attention to traffic signs Taking chances on the road Drifting into other lanes Getting more agitated in ...

  7. Control rod drive

    SciTech Connect

    Hawke, Basil C.

    1986-01-01

    A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

  8. Drive program documentation

    NASA Technical Reports Server (NTRS)

    Graham, S.

    1979-01-01

    The program description and user's guide for the Downlist Requirement Integrated Verification and Evaluation (DRIVE) program is provided. The program is used to compare existing telemetry downlist files with updated downlist requirements.

  9. Safe driving for teens

    MedlinePlus

    ... drivers. Do not use cell phones for talking, texting, or email when you are driving. Mobile phones ... pull off of the road before answering or texting. Other tips include: Avoid putting on makeup while ...

  10. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett Lee; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-09-19

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  11. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2007-02-27

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  12. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Stowell, Jesse; Costin, Daniel

    2006-07-11

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  13. Direct drive wind turbine

    DOEpatents

    Bywaters, Garrett; Danforth, William; Bevington, Christopher; Jesse, Stowell; Costin, Daniel

    2006-10-10

    A wind turbine is provided that minimizes the size of the drive train and nacelle while maintaining the power electronics and transformer at the top of the tower. The turbine includes a direct drive generator having an integrated disk brake positioned radially inside the stator while minimizing the potential for contamination. The turbine further includes a means for mounting a transformer below the nacelle within the tower.

  14. CONTROL ROD DRIVE

    DOEpatents

    Chapellier, R.A.

    1960-05-24

    BS>A drive mechanism was invented for the control rod of a nuclear reactor. Power is provided by an electric motor and an outside source of fluid pressure is utilized in conjunction with the fluid pressure within the reactor to balance the loadings on the motor. The force exerted on the drive mechanism in the direction of scramming the rod is derived from the reactor fluid pressure so that failure of the outside pressure source will cause prompt scramming of the rod.

  15. Common drive unit

    NASA Technical Reports Server (NTRS)

    Ellis, R. C.; Fink, R. A.; Moore, E. A.

    1987-01-01

    The Common Drive Unit (CDU) is a high reliability rotary actuator with many versatile applications in mechanism designs. The CDU incorporates a set of redundant motor-brake assemblies driving a single output shaft through differential. Tachometers provide speed information in the AC version. Operation of both motors, as compared to the operation of one motor, will yield the same output torque with twice the output speed.

  16. Maladaptive effects of learning with the less-affected forelimb after focal cortical infarcts in rats

    PubMed Central

    Allred, Rachel P.; Jones, Theresa A.

    2009-01-01

    It is common following stroke to focus early rehabilitation efforts on developing compensatory use of the less-affected body side. Here we used a rat model of focal cortical infarct to examine how motor skill acquisition with the less-affected (“intact”) forelimb influences sensorimotor function of the infarct-impaired forelimb and neural activity in peri-infarct cortex. Rats proficient in skilled reaching with one forelimb were given focal ischemic lesions in the contralateral sensorimotor cortex (SMC). Recovery in this forelimb was tested following a period of reach training focused on the intact forelimb or control procedures. Quantitative measures of the cumulatively expressed transcription factor, FosB/ΔFosB, were used to assay intact forelimb training effects on neuronal activity in remaining SMC of the infarcted hemisphere. Intact forelimb training worsened behavioral recovery in the impaired forelimb following unilateral focal ischemia. Furthermore, it decreased neuronal FosB/ΔFosB expression in layer II/III of peri-infarct SMC. These effects were not found in sham-operated rats trained sequentially with both forelimbs or in animals receiving bilateral forelimb training after unilateral infarcts. Thus, focused use of the intact forelimb has detrimental effects on recovery of impaired forelimb function following a focal ischemic injury and this is linked to reduced neuronal activation in remaining cortex. These results suggest that peri-infarct cortex becomes vulnerable to early post-stroke experience with the less-affected forelimb and that this experience may drive neural plasticity here in a direction that is maladaptive for functional outcome. PMID:18054917

  17. Sighting optics including an optical element having a first focal length and a second focal length and methods for sighting

    DOEpatents

    Crandall, David Lynn

    2011-08-16

    Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.

  18. Self-driving carsickness.

    PubMed

    Diels, Cyriel; Bos, Jelte E

    2016-03-01

    This paper discusses the predicted increase in the occurrence and severity of motion sickness in self-driving cars. Self-driving cars have the potential to lead to significant benefits. From the driver's perspective, the direct benefits of this technology are considered increased comfort and productivity. However, we here show that the envisaged scenarios all lead to an increased risk of motion sickness. As such, the benefits this technology is assumed to bring may not be capitalised on, in particular by those already susceptible to motion sickness. This can negatively affect user acceptance and uptake and, in turn, limit the potential socioeconomic benefits that this emerging technology may provide. Following a discussion on the causes of motion sickness in the context of self-driving cars, we present guidelines to steer the design and development of automated vehicle technologies. The aim is to limit or avoid the impact of motion sickness and ultimately promote the uptake of self-driving cars. Attention is also given to less well known consequences of motion sickness, in particular negative aftereffects such as postural instability, and detrimental effects on task performance and how this may impact the use and design of self-driving cars. We conclude that basic perceptual mechanisms need to be considered in the design process whereby self-driving cars cannot simply be thought of as living rooms, offices, or entertainment venues on wheels. PMID:26446454

  19. Parkinson disease and driving

    PubMed Central

    Classen, Sherrilene; Uc, Ergun Y.

    2012-01-01

    ABSTRACT The growing literature on driving in Parkinson disease (PD) has shown that driving is impaired in PD compared to healthy comparison drivers. PD is a complex neurodegenerative disorder leading to motor, cognitive, and visual impairments, all of which can affect fitness to drive. In this review, we examined studies of driving performance (on-road tests and simulators) in PD for outcome measures and their predictors. We searched through various databases and found 25 (of 99) primary studies, all published in English. Using the American Academy of Neurology criteria, a study class of evidence was assigned (I–IV, I indicating the highest level of evidence) and recommendations were made (Level A: predictive or not; B: probably predictive or not; C: possibly predictive or not; U: no recommendations). From available Class II and III studies, we identified various cognitive, visual, and motor measures that met different levels of evidence (usually Level B or C) with respect to predicting on-road and simulated driving performance. Class I studies reporting Level A recommendations for definitive predictors of driving performance in drivers with PD are needed by policy makers and clinicians to develop evidence-based guidelines. PMID:23150533

  20. Hydraulic drive system prevents backlash

    NASA Technical Reports Server (NTRS)

    Acord, J. D.

    1965-01-01

    Hydraulic drive system uses a second drive motor operating at reduced torque. This exerts a relative braking action which eliminates the normal gear train backlash that is intolerable when driving certain heavy loads.

  1. Family Influences and Unconscious Drives.

    ERIC Educational Resources Information Center

    English, Fanita

    2001-01-01

    Drives for survival, expression, and quiescence influence early human development and continue to influence career development throughout life. Turmoil may arise when a drive conflicts with others or is suppressed by other drives. (SK)

  2. Intraplate Stress Field in Brazil Using Focal Mechanisms: Regional and Local Patterns: Examples of Regional Forces Controlling the Stress Field

    NASA Astrophysics Data System (ADS)

    Dias, F. L.; Assumpcao, M.

    2014-12-01

    The knowledge of stress field is fundamental not only to understand driving forces and plate deformation but also in the study of intraplate seismicity. In Brazil, the stress field has been determined mainly using focal mechanisms and a breakout data and in-situ measurements. However, the stress field still is poorly known in Brazil. We show a recent compilation of focal mechanism determined in Brazil (Fig 1). The focal mechanisms of some recent earthquakes (magnitude lower than 5 mb) were studied using waveform modeling. We stacked the record of several teleseismic stations (> 30°) with a good signal/noise ratio and we grouped then according to distance and azimuth. With the focal mechanisms available in literature and those obtained in this work, we were able to identify some patterns: the central region shows compressional pattern (E-W SHmax), which is predicted by regional theoretical models ( Coblentz & Richardson, 1996 and the TD0 model of Lithgow & Bertelloni, 2004). This compression is mainly due to the interaction of tectonic plate forces. Meanwhile in the Amazon region, we find an indication of SHMax oriented in the SE-NW direction, probably caused by the Caribbean plate interaction (Meijer, 1995) and Amazon Fan, we have flexural stresses caused by sedimentary load with is in agreement with local theoretical models (Watts et al., 2009) . In northern coastal region, the compression rotates following the coastline, which indicates an important local component related to spreading effects at the continental/oceanic transition (Assumpção, 1998). We determine the focal mechanism of several events in Brazil using different techniques according to the available data. The major difficulty is to determine focal mechanism of low magnitudes events (< 5.0 mb) using distant or few seismograph stations. We find examples of stress perturbations induced by local effects (e.g. flexure and continental spreading). The results of this work should be useful for future

  3. Mental workload and driving

    PubMed Central

    Paxion, Julie; Galy, Edith; Berthelon, Catherine

    2014-01-01

    The aim of this review is to identify the most representative measures of subjective and objective mental workload in driving, and to understand how the subjective and objective levels of mental workload influence the performance as a function of situation complexity and driving experience, i.e., to verify whether the increase of situation complexity and the lack of experience increase the subjective and physiological levels of mental workload and lead to driving performance impairments. This review will be useful to both researchers designing an experimental study of mental workload and to designers of drivers’ training content. In the first part, we will broach the theoretical approach with two factors of mental workload and performance, i.e., situation complexity and driving experience. Indeed, a low complex situation (e.g., highways), or conversely a high complex situation (e.g., town) can provoke an overload. Additionally, performing the driving tasks implies producing a high effort for novice drivers who have not totally automated the driving activity. In the second part, we will focus on subjective measures of mental workload. A comparison of questionnaires usually used in driving will allow identifying the most appropriate ones as a function of different criteria. Moreover, we will review the empirical studies to verify if the subjective level of mental workload is high in simple and very complex situations, especially for novice drivers compared to the experienced ones. In the third part, we will focus on physiological measures. A comparison of physiological indicators will be realized in order to identify the most correlated to mental workload. An empirical review will also take the effect of situation complexity and experience on these physiological indicators into consideration. Finally, a more nuanced comparison between subjective and physiological measures will be established from the impact on situation complexity and experience. PMID:25520678

  4. [Color Doppler sonography of focal abdominal lesions].

    PubMed

    Licanin, Zoran; Lincender, Lidija; Djurović, V; Salihefendić, Nizama; Smajlović, Fahrudin

    2004-01-01

    Color Doppler sonography (CDS--spectral, color and power), harmonic imaging techniques (THI, PHI), possibility of 3D analysis of picture, usage of contrast agents, have raised the values of ultrasound as a diagnostic method to a very high level. THI--non-linear gray scale modality, is based on the processing of higher reflected frequencies, that has improved a picture resolution, which is presented with less artifacts and limiting effects of obesity and gases. Ultrasound contrast agents improve analysis of micro and macro circulation of the examined area, and with the assessment of velocity of supply in ROI (wash in), distribution and time of signal weakening (wash out), are significantly increasing diagnostic value of ultrasound. Besides the anatomical and topographic presentation of examined region (color, power), Color Doppler sonography gives us haemodynamic-functional information on vascularisation of that region, as well as on pathologic vascularisation if present. Avascular aspect of a focal pathologic lesion corresponds to a cyst or haematoma, while coloration and positive spectral curve discover that anechogenic lesions actually represents aneurysms, pseudoaneurysms or AVF. In local inflammatory lesion, abscess in an acute phase, CDS shows first increased, and then decreased central perfusion, while in a chronic phase, a pericapsular vascularisation is present. Contribution of CDS in differentiation of hepatic tumors (hemangioma, HCC and metastasis) is very significant. Central color dots along the peripheral blood vessels and the blush phenomenon are characteristics of capillary hemangioma, peritumoral vascular ring "basket" of HCC, and "detour" sign of metastasis. The central artery, RI from 0.45 to 0.60 and radial spreading characterize FNH. Hepatic adenoma is characterized by an intratumoral vein, and rarely by a vascular hallo. Further on, blood velocity in tumor defined by Color Doppler, distinguishes malignant from benign lesion, where 40 cm/s is a

  5. Combined Scanning Transmission Electron Microscopy Tilt- and Focal Series

    SciTech Connect

    Dahmen, Tim; Baudoin, Jean-Pierre G; Lupini, Andrew R; Kubel, Christian; Slusallek, Phillip; De Jonge, Niels

    2014-01-01

    In this study, a combined tilt- and focal series is proposed as a new recording scheme for high-angle annular dark-field scanning transmission electron microscopy (STEM) tomography. Three-dimensional (3D) data were acquired by mechanically tilting the specimen, and recording a through-focal series at each tilt direction. The sample was a whole-mount macrophage cell with embedded gold nanoparticles. The tilt focal algebraic reconstruction technique (TF-ART) is introduced as a new algorithm to reconstruct tomograms from such combined tilt- and focal series. The feasibility of TF-ART was demonstrated by 3D reconstruction of the experimental 3D data. The results were compared with a conventional STEM tilt series of a similar sample. The combined tilt- and focal series led to smaller missing wedge artifacts, and a higher axial resolution than obtained for the STEM tilt series, thus improving on one of the main issues of tilt series-based electron tomography.

  6. Driving Anger and Driving Behavior in Adults with ADHD

    ERIC Educational Resources Information Center

    Richards, Tracy L.; Deffenbacher, Jerry L.; Rosen, Lee A.; Barkley, Russell A.; Rodricks, Trisha

    2006-01-01

    Objective: This study assesses whether anger in the context of driving is associated with the negative driving outcomes experienced by individuals with ADHD. Method: ADHD adults (n = 56) complete measures of driving anger, driving anger expression, angry thoughts behind the wheel, and aggressive, risky, and crash-related behavior. Results are…

  7. Focal interictal epileptiform discharges in idiopathic generalized epilepsy.

    PubMed

    Esmail, Eman H; Nawito, Amani M; Labib, Dalia M; Basheer, Mye A

    2016-07-01

    Are idiopathic generalized epilepsies (IGEs) truly generalized? Do IGEs represent a continuum or rather distinct syndromes? Focal changes in the electroencephalography (EEG) have been reported in IGEs. The aim of this work is to investigate focal interictal epileptiform discharges (IEDs) in IGEs, and their relation to clinical variables. Forty-one IGE patients (classified according to ILAE, 2001) were recruited from a tertiary center (age 23 ± 10.938 years). Their files were reviewed and they were subjected to clinical examination and interictal EEG. Patients with focal IEDs were compared to those without focal IEDs. Nine patients had juvenile myoclonic epilepsy (JME) and 32 had idiopathic epilepsy with generalized tonic-clonic seizures only (EGTCSA). Focal IEDs were found in 20 patients, mostly in the frontal (45.5 %) and temporal (31.8 %) distribution. Patients with focal IEDs were treated with a larger number of combined antiepileptic drugs (AEDs) (p value = 0.022). No significant difference was found between the two groups regarding age, sex, age at onset, epilepsy syndrome, seizure frequency, family history, AEDs used (sodium valproate and carbamazepine) and their doses. Seventeen EGTCSA patients had focal IEDs. They were treated with larger number of combined AEDs (p value = 0.0142). No significant difference was found between the EGTCSA patients with and those without focal IEDs regarding age, sex, age at onset, seizure frequency, family history and AEDs doses. Caution must be applied in the interpretation of interictal focal IEDs. These focal changes may be related to prognosis, however this needs further investigation. PMID:26956566

  8. An empirical assessment of the focal species hypothesis.

    PubMed

    Lindenmayer, D B; Lane, P W; Westgate, M J; Crane, M; Michael, D; Okada, S; Barton, P S

    2014-12-01

    Biodiversity surrogates and indicators are commonly used in conservation management. The focal species approach (FSA) is one method for identifying biodiversity surrogates, and it is underpinned by the hypothesis that management aimed at a particular focal species will confer protection on co-occurring species. This concept has been the subject of much debate, in part because the validity of the FSA has not been subject to detailed empirical assessment of the extent to which a given focal species actually co-occurs with other species in an assemblage. To address this knowledge gap, we used large-scale, long-term data sets of temperate woodland birds to select focal species associated with threatening processes such as habitat isolation and loss of key vegetation attributes. We quantified co-occurrence patterns among focal species, species in the wider bird assemblage, and species of conservation concern. Some, but not all, focal species were associated with high levels of species richness. One of our selected focal species was negatively associated with the occurrence of other species (i.e., it was an antisurrogate)-a previously undescribed property of nominated focal species. Furthermore, combinations of focal species were not associated with substantially elevated levels of bird species richness, relative to levels associated with individual species. Our results suggest that although there is some merit to the underpinning concept of the FSA, there is also a need to ensure that actions are sufficiently flexible because management tightly focused on a given focal species may not benefit some other species, including species of conservation concern, such of which might not occur in species-rich assemblages. PMID:25048948

  9. Control of intracellular pH and growth by fibronectin in capillary endothelial cells

    NASA Technical Reports Server (NTRS)

    Ingber, D. E.; Prusty, D.; Frangioni, J. V.; Cragoe, E. J. Jr; Lechene, C.; Schwartz, M. A.

    1990-01-01

    The aim of this work was to analyze the mechanism by which fibronectin (FN) regulates capillary endothelial cell proliferation. Endothelial cell growth can be controlled in chemically-defined medium by varying the density of FN coated on the substratum (Ingber, D. E., and J. Folkman. J. Cell Biol. 1989. 109:317-330). In this system, DNA synthetic rates are stimulated by FN in direct proportion to its effect on cell extension (projected cell areas) both in the presence and absence of saturating amounts of basic FGF. To investigate direct growth signaling by FN, we carried out microfluorometric measurements of intracellular pH (pHi), a cytoplasmic signal that is commonly influenced by soluble mitogens. pHi increased 0.18 pH units as FN coating densities were raised and cells progressed from round to spread. Intracellular alkalinization induced by attachment to FN was rapid and followed the time course of cell spreading. When measured in the presence and absence of FGF, the effects of FN and FGF on pHi were found to be independent and additive. Furthermore, DNA synthesis correlated with pHi for all combinations of FGF and FN. Ethylisopropylamiloride, a specific inhibitor of the plasma membrane Na+/H+ antiporter, completely suppressed the effects of FN on both pHi and DNA synthesis. However, cytoplasmic pH per se did not appear to be a critical determinant of growth since DNA synthesis was not significantly inhibited when pHi was lowered over the physiological range by varying the pH of the medium. We conclude that FN and FGF exert their growth-modulating effects in part through activation of the Na+/H+ exchanger, although they appear to trigger this system via separate pathways.

  10. Improved fibronectin-immobilized fibrinogen microthreads for the attachment and proliferation of fibroblasts

    PubMed Central

    Rajangam, Thanavel; An, Seong Soo A

    2013-01-01

    The aim of this study was to fabricate fibrinogen (Fbg) microfibers with different structural characteristics for the development of 3-D tissue-engineering scaffolds. Fabricated Fbg microfibers were investigated for their biomolecule encapsulation, cell adhesion, and proliferations. Microfibers with three different concentrations of Fbg (5, 10, and 15 wt%) were prepared by a gel solvent-extraction method using a silicone rubber tube. Fbg microfibers were covalently modified with fibronectin (FN) by using water-soluble 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as the cross-linking agent. Fbg microfibers were characterized by their FN cross-linking properties, structural morphology, and in vitro degradation. Furthermore, FN/Fbg microfibers were evaluated for cell attachment and proliferation. The bio-compatibility and cell proliferation of the microfibers were assessed by measuring adenosine triphosphate activity in C2C12 fibroblast cells. Cell attachment and proliferation on microfibers were further examined using fluorescence and scanning electron microscopic images. FN loading on the microfibers was confirmed by fluorescence and infrared spectroscopy. Surface morphology was characterized by scanning electron microscopy, and showed highly aligned nanostructures for fibers made with 15 wt% Fbg, a more porous structure for fibers made with 10 wt% Fbg, and a less porous structure for those made with 5 wt% Fbg. Controlled biodegradation of the fiber was observed for 8 weeks by using an in vitro proteolytic degradation assay. Fbg microfibers with highly aligned nanostructures (15 wt%) showed enhanced biomolecule encapsulation, as well as higher cell adhesion and proliferation than another two types of FN/Fbg fibers (5 and 10 wt%) and unmodified Fbg fibers. The promising results obtained from the present study reveal that optimal structure of Fbg microfibers could be used as a potential substratum for growth factors or drug release, especially in wound healing and

  11. Fibronectin and other DIC-related variables in patients with moderately severe infections receiving cryoprecipitate.

    PubMed

    Brodin, B; Hesselvik, F; Blombäck, M; Cedergren, B; Lieden, G; Maller, R; Strindberg, J

    1985-01-01

    Plasma fibronectin (Fn), a glucoprotein of suggested importance in host defence during infections also seems to be involved in blood coagulation and to be consumed during clot formation. Low Fn concentrations have been found in patients with DIC, but also in patients with infections without signs of overt DIC. In a randomized trial of Fn supplementation 28 patients with moderately severe infections, hospitalized in the Department for Infectious Diseases, were scheduled to receive either cryoprecipitate from 30 donors (n = 14) or 250-300 ml of stored plasma (n = 14). To elucidate the relationship between Fn plasma levels, Fn-rich cryoprecipitate infusion, and possible low-grade DIC in these patients, we measured platelet count, prothrombin complex (NT), fibrinogen, F V, F VIIIR:Ag, F VIII:C, F XII, plasminogen (Plg), antiplasmin (AP), antithrombin III (AT), kallikrein-inhibiting activity (KI) and spontaneous proteolytic activity (SPA). Compared to healthy controls, high initial values (p less than .001) were found for fibrinogen, F VIIIR:Ag, F VIII:C and SPA. Most values for platelets, F V, Plg, AP and KI were within the reference range. Low levels (p less than .001) were found for Fn, NT, F XII, AT and for the ratio F VIII:C/F CIIIR:Ag. A significant correlation was found between F XII, Plg and AT. Fn correlated poorly to the other variables. Cryoprecipitate infusion normalized the Fn concentration, but had no influence on other measured variables. Thus, although no patient had clinically overt DIC, and all survived, we observed a distinct pattern indicating activation of the coagulation system. Fn levels were low, but were not specifically related to this activation. PMID:3937219

  12. Quantitative microtiter fibronectin fibrillogenesis assay: use in high throughput screening for identification of inhibitor compounds

    PubMed Central

    Tomasini-Johansson, Bianca R.; Johnson, Ian A.; Hoffmann, F. Michael; Mosher, Deane F.

    2012-01-01

    Fibronectin (FN) is a plasma glycoprotein that circulates in the near micromolar concentration range and is deposited along with locally produced FN in the extracellular matrices of many tissues. Control of FN deposition is tightly controlled by cells. Agents that modulate FN assembly may be useful therapeutically in conditions characterized by excessive FN deposition, such as fibrosis, inflammatory diseases, and malignancies. To identify such agents by high throughput screening (HTS), we developed a microtiter assay of FN deposition by human fibroblasts. The assay provides a robust read-out of FN assembly. Alexa 488-FN (A488-FN) was added to cell monolayers, and the total fluorescence intensity of deposited A488-FN was quantified. The fluorescence intensity of deposited A488-FN correlated with the presence of FN fibrils visualized by fluorescence microscopy. The assay Z’ values were 0.67 or 0.54, respectively, when using background values of fluorescence either with no added A488-FN or with A488-FN added together with a known inhibitor of FN deposition. The assay was used to screen libraries comprising 4160 known bioactive compounds. Nine compounds were identified as non- or low-cytotoxic inhibitors of FN assembly. Four (ML-9, HA-100, tyrphostin and imatinib mesylate) are kinase inhibitors, a category of compounds known to inhibit FN assembly; two (piperlongumine and cantharidin) are promoters of cancer cell apoptosis; and three (maprotiline, CGS12066B, and aposcopolamine) are modulators of biogenic amine signaling. The latter six compounds have not been recognized heretofore as affecting FN assembly. The assay is straight-forward, adapts to 96- and 384-well formats, and should be useful for routine measurement of FN deposition and HTS. Screening of more diverse chemical libraries and identification of specific and efficient modulators of FN fibrillogenesis may result in therapeutics to control excessive connective tissue deposition. PMID:22986508

  13. Titanium dioxide nanoparticles disturb the fibronectin-mediated adhesion and spreading of pre-osteoblastic cells.

    PubMed

    Bernier, Marie-Charlotte; Besse, Marie; Vayssade, Muriel; Morandat, Sandrine; El Kirat, Karim

    2012-09-25

    In the context of rapid development of nanoparticles (NPs) for industrial applications, the question of their toxicity and biological effects must be considered. In this work, we have assessed the influence of titanium dioxide NPs on the adhesion and spreading of MC-3T3 pre-osteoblasts by using a cell subclone that does not produce its own extracellular matrix. Petri dishes were coated with the important adhesion protein fibronectin (Fn). By incubating these Fn-coated surfaces with different amounts of TiO(2) NPs, we have shown that the adhesion of pre-osteoblasts is disturbed, with an important decrease in the number of adherent cells (from 40 to 75% depending upon the concentration and type of NPs). Petri-dish surfaces were analyzed with environmental scanning electron microscropy (ESEM), with images showing that TiO(2) NP aggregates are bound to the layer of adsorbed Fn molecules. The cells cultured on these Fn/NP surfaces adopted an irregular shape and an aberrant organization of actin cytoskeleton, as revealed by fluorescence microscopy. Most importantly, these results, taken together, have revealed that the actin cytoskeleton forms abnormal aggregates, even on top of the nucleus, that coincide with the presence of large aggregates of NPs on top of cells. On the basis of these observations, we propose that some Fn molecules are able to desorb from the Petri dish surface to coat TiO(2) NPs. Fn/NP complexes are not attached firmly enough on the surface to allow for normal cell adhesion/spreading and the development of tense actin fibers. These results stress the paramount need for the assessment of the toxicology of NPs, with special attention to their interactions with biomolecules. PMID:22934655

  14. Pegylation of fibronectin and its functional domains: Effect on stability and biological activity

    NASA Astrophysics Data System (ADS)

    Zhang, Chen

    Delayed wound healing in many chronic wounds has been linked to the lack of extracellular matrix (ECM) support and the degradation of fibronectin (FN) by an abnormally high protease level. The ECM provides physical and chemical cues that direct tissue growth and development while FN is a key ECM protein that attracts and binds different molecules and cells. The goal of my study is creating an ECM analogue based on a composite of polyethylene glycol (PEG) hydrogels and FN binding domains and stabilizing FN against proteolytic degradation by conjugating it to PEG. The work presented here shows a two-prong approach by which the problem of ECM degradation and deficiency chronic wound healing can be addressed. The first approach for addressing ECM deficiency is through a scaffold design methodology. The novelty of the scaffold approach is that it uses the cell-binding domains of FN instead of the often-used RGD peptide. I demonstrate that a PEG hydrogel with the cell-binding domain produces a more robust biological response in cells than a PEG hydrogel with the RGD peptide. I also demonstrate that varying different functional domains of FN can be used to controllably stimulate multiple biological responses. The second approach demonstrates a method by which FN, a key ECM protein, is stabilized against proteolytic degradation without perturbing its activity. These studies of creating PEG-FN conjugates are the first of their kind. Collectively, the data that I present in this thesis will lead to novel therapeutic methods for treating chronic wounds.

  15. Fibronectin gene expression, synthesis and accumulation during in vitro differentiation of chicken osteoblasts

    NASA Technical Reports Server (NTRS)

    Winnard, R. G.; Gerstenfeld, L. C.; Toma, C. D.; Franceschi, R. T.; Landis, W. J. (Principal Investigator)

    1995-01-01

    A well-defined chicken osteoblast culture system(18) has been used to examine fibronectin (FN) mRNA levels, synthesis, and accumulation during in vitro differentiation and matrix mineralization. Immunofluorescent staining of cells after 6 or 18 days in culture revealed that FN was initially associated with the cell surface and in partial coalignment with cytoskeletal elements while at the latter time most FN was associated with the extracellular matrix as a ubiquitous fibrillar network. Western blot analysis of total cell-associated proteins also detected FN at all culture times. However, when results were normalized to cellular DNA, FN levels increased until 12-16 and remained relatively constant thereafter. Similarly, FN synthesis as measured by [35S]-methionine labeling, and immunoprecipitation was greatest in early cultures (culture day 3) and then declined such that synthesis decreased 60% at day 18 and 94% after 24-31 days. FN mRNA levels as measured by Northern blot analysis were well correlated with FN synthesis. These results clearly show that FN is made by primary osteoblasts during their in vitro maturation. In contrast to other osteoblast markers such as alkaline phosphatase, osteocalcin, and osteopontin, whose expression increases as cells differentiate, FN accumulates in the matrix during periods of early cell growth and attachment and then remains proportional to cell number. Results with FN differ from those obtained with collagen which continues to accumulate in the extracellular matrix during osteoblast maturation. These results are consistent with FN being important for the initial attachment of early osteoblasts or osteoblast precursors to the pericellular matrix.

  16. Clinical Application of Surface Plasmon Resonance-Based Biosensors for Fetal Fibronectin Detection

    PubMed Central

    Chen, Chen-Yu; Chang, Chia-Chen; Yu, Chun; Lin, Chii-Wann

    2012-01-01

    Preterm birth is the leading cause of perinatal morbidity and mortality. Fetal fibronectin (fFN), a glycoprotein in the extracellular matrix of the amniotic membranes, is the most powerful biomarker for predicting the risk of preterm birth. Biosensors using the surface plasmon resonance (SPR) response are potentially useful in quantitatively measuring molecules. We established a standard calibration curve of SPR intensity against fFN concentration and used the SPR-based biosensor to detect fFN concentrations in the cervicovaginal secretions of pregnant women between 22 and 34 weeks of gestation. The calibration curve extends from 0.5 ng/mL to 100 ng/mL with an excellent correlation (R2 = 0.985) based on standard fFN samples. A cutoff value of 50 ng/mL fFN concentration in commercial ELISA kits corresponds to a relative intensity of 17 arbitrary units (a.u.) in SPR. Thirty-two pregnant women were analyzed in our study. In 11 women, the SPR relative intensity was greater than or equal to 17 a.u., and in 21 women, the SPR relative intensity was less than 17 a.u. There were significant differences between the two groups in regular uterine contractions (p = 0.040), hospitalization for tocolysis (p = 0.049), and delivery weeks (p = 0.043). Our prospective study concluded that SPR-based biosensors can quantitatively measure fFN concentrations. These results reveal the potential utility of SPR-based biosensors in predicting the risk of preterm birth. PMID:22666007

  17. Monocyte activation by circulating fibronectin fragments in HIV-1-infected patients.

    PubMed

    Trial, JoAnn; Rubio, Jose A; Birdsall, Holly H; Rodriguez-Barradas, Maria; Rossen, Roger D

    2004-08-01

    To identify signals that can alter leukocyte function in patients receiving highly active antiretroviral therapy (HAART), we analyzed single blood samples from 74 HIV-1-infected patients and additional blood was collected at 90-day intervals from 51 HIV-1-infected patients over a 516 +/- 172 (mean +/- SD) day interval. Despite the absence of circulating immune complexes and normalization of phagocytic function, compared with controls, the fraction of patients' monocytes expressing CD49e and CD62L was decreased and expression of CD11b and CD86 increased. Plasma from 63% of patients but none from normal controls contained 110-120 kDa fibronectin fragments (FNf). Presence of FNf did not reflect poor adherence to therapy. Addition of FNf to normal donor blood in vitro replicated changes in monocyte CD49e, CD62L, CD11b, and CD86 seen in vivo. FNf also induced monocytes to release a serine proteinase, nominally identified as proteinase-3, that hydrolyzed cell surface CD49e. alpha(1)-Antitrypsin blocked FNf-induced shedding of CD49e in a dose-dependent manner. Plasma with a normal frequency of CD49e(+) monocytes contained antiproteases that partially blocked FNf-induced monocyte CD49e shedding, whereas plasma from patients with a low frequency of CD49e(+) monocytes did not block this effect of FNf. Electrophoretic analyses of plasma from the latter group of patients suggested that a significant fraction of their alpha(1)-antitrypsin was tied up in high molecular mass complexes. These results suggest that monocyte behavior in HIV-1-infected patients may be influenced by FNf and the ratio of protease and antiproteases in the cells' microenvironment. PMID:15265957

  18. Effect of auranofin on plasma fibronectin, C reactive protein, and albumin levels in arthritic rats.

    PubMed Central

    Connolly, K M; Stecher, V J; Pruden, D J

    1988-01-01

    Auranofin, a member of a class of compounds with disease modifying activity, was given to arthritic rats to determine if it could reverse the abnormal plasma concentrations of fibronectin (Fn), C reactive protein (CRP), and albumin, which were unaffected by treatment with non-steroidal anti-inflammatory drugs (NSAIDs). When auranofin was orally administered for two weeks to adjuvant induced arthritic rats it significantly inhibited swelling of the injected and non-injected paws at doses of 3 and 10 mg/kg. Rocket electroimmunoassay measurement of plasma proteins in normal, arthritic, and auranofin treated arthritic rats indicated that auranofin at 10 mg/kg significantly decreased (by 77%) the abnormally high concentration of arthritic rat plasma Fn, though it had no effect on Fn concentrations when administered to normal rats. CRP, which was raised approximately twofold above normal in arthritic rats, was reduced by 56% after treatment of arthritic rats with auranofin at 10 mg/kg, though CRP concentrations in normal rats were unaffected by auranofin treatment. Depressed albumin concentrations in arthritic rats were significantly enhanced (by 30%) by dosing with 10 mg/kg of auranofin. At the 3 mg/kg dose, auranofin did not significantly change plasma concentrations of Fn, CRP, and albumin in arthritic rats. At a dose of 10 mg/kg, however, auranofin, in addition to inhibiting chronic systemic paw inflammation, also altered abnormal concentrations of plasma Fn, CRP, and albumin in the adjuvant arthritic rat, thus distinguishing auranofin from standard NSAIDs we have previously tested. PMID:3260094

  19. Silence of fibronectin 1 increases cisplatin sensitivity of non-small cell lung cancer cell line.

    PubMed

    Gao, Weiwei; Liu, Ying; Qin, Ruiling; Liu, Daijian; Feng, Qingqing

    2016-07-15

    Fibronectin 1 (FN1) is a member of the glycoprotein family which is widely expressed by multiple cell types and involved in cellular adhesion and migration processes. Recent studies have reported that FN1 might have a role in regulating chemoresistance in tumors. However, the regulation of FN1 on cisplatin resistance in non-small cell lung cancer (NSCLC) has not been investigated. The present study aims to illustrate the effect of FN1 on cisplatin resistance in NSCLC and explore potential mechanisms. In the present study, the mRNA and protein expression levels of FN1 were investigated by RT-PCR and Western blot analysis, respectively, and the 50% inhibitory concentration (IC50) value of cisplatin was measured by MTT assay. Apoptotic ratio and migration were determined using an annexin V-FITC/PI detection kit and a Transwell assay, respectively. The interaction between FN1 and integrin-β1 was evaluated by co-immunoprecipitation assay. The protein expression of β-catenin, cyclin D1 and c-myc were tested using Western blot analysis. The results showed that FN1 was more highly expressed in A549/DDP than in A549 cells, and significantly upregulated by cisplatin treatment in H1299 cells. Knockdown of FN1 reduced the IC50 value of cisplatin, inhibited cell migration and promoted apoptosis. FN1 and integrin-β1 protein directly interacted with each other both in A549 and A549/DDP cells. FN1 silencing suppressed the Wnt/β-catenin signaling pathway, and this effect was dampened by integrin-β1-blocking antibody. Taken together, our findings first suggest that FN1 plays a role in the development of cisplatin resistance in NSCLC, possibly by modulation of β-catenin signaling through interaction with integrin-β1 in NSCLC. PMID:27207836

  20. Native and fragmented fibronectin oppositely modulate monocyte secretion of MMP-9.

    PubMed

    Marom, Barak; Rahat, Michal A; Lahat, Nitza; Weiss-Cerem, Lea; Kinarty, Amalia; Bitterman, Haim

    2007-06-01

    Monocytes remodel the extracellular matrix (ECM) by secreting proteins composing the ECM such as fibronectin (FN) and degrading proteases such as matrix metalloproteinase-9 (MMP-9), which cleaves FN into fragments. The effects of FN and its fragmented products on the expression of monocyte MMP-9 are controversial and largely unknown. We showed that in human monocytes, the proinflammatory cytokine TNF-alpha induced MMP-9 secretion and increased fragmentation of FN into distinct fragments. When primary monocytes or the U937 monocytic cell line were incubated on a plastic substrate, plastic-coated with native FN, and plastic-coated with fragmented FN (frag-FN), native FN inhibited TNF-alpha-induced proMMP-9 secretion by twofold (P<0.01) compared with plastic or frag-FN. Exploration of the dynamics of inflammation by incubating cells sequentially on the three substrates showed that frag-FN opposed the inhibitory effect of native FN. Inhibition of proMMP-9 by native FN was exerted at the translational level, as no change in MMP-9 mRNA, intracellular protein accumulation, or proteomic degradation was observed, and when degradation was blocked, no de novo translation of MMP-9 could be measured. We also showed that the reduction of MMP-9 secretion by native FN was responsible for attenuated migration of U937 cells (P<0.05). We suggest that in the inflammatory tissue, intact, native FN has a homeostatic role in harnessing MMP-9 activity. However, as fragmented products accumulate locally, they alleviate the inhibition and enable faster migration of the monocytes through the degraded ECM. PMID:17327485