Navegando por Palavras-chave "laminin"

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    Autoantibodies directed to extracellular matrix components in patients with different clinical forms of periodontitis
    (Amer Acad Periodontology, 2006-12-01) De-Gennaro, Luiz A.; Lopes, Jose D.; Mariano, Mario; Universidade Federal de São Paulo (UNIFESP)
    Background: Periodontal disease occurs in different clinical forms, from mild and easily controllable to more aggressive inflammatory manifestations, with difficult clinical or surgical control. There is evidence that a local autoimmune reaction may participate in the onset and persistence of the aggressive forms of periodontal disease. As the underlying mechanism in this process is not fully understood, we decided to investigate whether patients bearing this form of disease presented higher levels of antibodies directed to extracellular matrix (ECM) components such as type I collagen, fibronectin, and laminin.Methods: Three groups of patients were selected by clinical criteria: 22 subjects with aggressive periodontitis (AgP) = group A; 18 subjects with chronic periodontitis (CP) = group B; and 10 healthy (H) volunteers without periodontal disease = group C. Autoantibody levels were evaluated in the sera of these patients using the enzyme-linked immunosorbent assay (ELISA) method.Results: the levels of autoantibodies directed to ECM components (type I collagen, fibronectin and laminin) in the sera of patients with AgP and CP were shown to be statistically different (P < 0.05).Conclusions: Although the present findings suggest an involvement of autoantibodies directed to ECM components per se in the pathogeny of certain types of periodontal disease, the available data do not support the classification of the lesions as autoimmune. Nevertheless, the findings open a possibility for the development of an additional method for a differential diagnosis of the aggressive forms of periodontal disease.
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    Binding of laminin to Paracoccidioides brasiliensis induces a less severe pulmonary paracoccidioidomycosis caused by virulent and low-virulence isolates
    (Elsevier B.V., 2004-05-01) Andre, D. C.; Lopes, J. D.; Franco, M. F.; Vaz, CAC; Calich, VLG; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The pathogenic fungus Parracoccidioides brasiliensis is the causative agent of paraeoccidioidomycosis (PCM). This pulmonary mycosis, acquired by inhalation of airborne propagules, may disseminate to several internal organs and tissues, leading to severe disease. Adhesion to host cell components is the first step involved in dissemination of pathogens. Previous studies showed that laminin, the most abundant glycoprotein of the basement membrane, binds to P. brasiliensis yeast cells, enhancing their pathogenicity in the hamster testicle model. As PCM is primarily a pulmonary infection, we studied the influence of previous treatment of yeast cells with laminin on the course of the intratracheal infection of resistant and susceptible mice using high-virulence (Pb18) and low-virulence (Pb265) P. brasiliensis isolates. Laminin treatment did not alter fungal loads, delayed-type hypersensitivity reactions, levels of pulmonary cytokines and production of specific antibodies in any group of Pb18-infected mice. However, early in the infection, a less intense inflammatory reaction was detected in the lungs of the laminin-treated groups. in addition, laminin treatment of P6265 resulted in a less severe infection as revealed by the lower fungal loads recovered from lungs. Antibody and cytokine levels, however, did not change after laminin treatment. Altogether, our results demonstrate that laminin binding to yeast cells diminishes P. brasiliensis pathogenicity. the lower inflammatory response observed with the virulent isolate and the decreased pulmonary fungal burden with the low-virulence isolate indicate an inhibitory effect of laminin treatment on P. brasiliensis infectivity and interaction with pulmonary host cells or extracellular matrix proteins. (C) 2004 Elsevier SAS. All rights reserved.
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    Cellular prion protein binds laminin and mediates neuritogenesis
    (Elsevier B.V., 2000-03-10) Graner, E.; Mercadante, A. F.; Zanata, S. M.; Forlenza, O. V.; Cabral, ALB; Veiga, S. S.; Juliano, M. A.; Roesler, R.; Walz, R.; Minetti, A.; Izquierdo, I; Martins, V. R.; Brentani, R. R.; Ludwig Inst Canc Res; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); UFRGS; Ctr Tratamento; Pesquisa Hosp Canc
    Laminin (LN) plays a major role in neuronal differentiation, migration and survival. Here, we show that the cellular prion protein (PrPc) is a saturable, specific, high-affinity receptor for LN. the PrPc-LN interaction is involved in the neuritogenesis induced by NGF plus LN in the PC-12 cell line and the binding site resides in a carboxy-terminal decapeptide from the gamma-1 LN chain. Neuritogenesis induced by LN or its gamma-1-derived peptide in primary cultures from rat or either wild type or PrP null mice hippocampal neurons, indicated that PrPc is the main cellular receptor for that particular LN domain. These results point out to the importance of the PrPc-LN interaction for the neuronal plasticity mechanism. (C) 2000 Elsevier Science B.V. All rights reserved.
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    Extracellular matrix alterations in experimental murine Leishmania (L.) amazonensis infection
    (Cambridge Univ Press, 2004-04-01) Abreu-Silva, A. L.; Calabrese, K. S.; Mortara, R. A.; Tedesco, R. C.; Cardoso, F. O.; Carvalho, LOP; Da Costa, SCG; Univ Estadual Maranhao; Fiocruz MS; Universidade Federal de São Paulo (UNIFESP)
    Here we describe extracellular matrix alterations in footpad lesions and draining lymph nodes caused by Leishmania (L.) amazonensis in mouse strains with distinct susceptibilities to this parasite: BALB/c (susceptible), C57BL/6 (intermediate), and DBA/2 (resistant). Changes in ECM were observed mainly in BALB/c mice that, in general, presented tissue damage associated with high parasite burden. Under polarized light, Sirius Red revealed type I collagen that was predominant in the primary lesion in all strains studied at the early phase of infection, but gradually decreased and was replaced by abundant type III collagen fibre in chronic phase lesions. the presence of type III collagen seemed to provide support to inflammatory cells, mainly vacuolated and parasitized macrophages. Laminin expression was not altered during infection by L. (L.) amazonensis in any of the mouse strains studied. Furthermore, the decreased fibronectin expression, in all strains, in areas where amastigotes have been found, indicated that this decline was also not related to the genetic background.
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    Functional differences between two morphologically distinct cell subpopulations within a human colorectal carcinoma cell line
    (Associação Brasileira de Divulgação Científica, 2001-05-01) Solimene, A.c.c. [UNIFESP]; Carneiro, Celia Regina Whitaker [UNIFESP]; Melati, I. [UNIFESP]; Lopes, Jose Daniel [UNIFESP]; Fundação Antônio Prudente; Universidade Federal de São Paulo (UNIFESP)
    The LISP-I human colorectal adenocarcinoma cell line was isolated from a hepatic metastasis at the Ludwig Institute, São Paulo, SP, Brazil. The objective of the present study was to isolate morphologically different subpopulations within the LISP-I cell line, and characterize some of their behavioral aspects such as adhesion to and migration towards extracellular matrix components, expression of intercellular adhesion molecules and tumorigenicity in vitro. Once isolated, the subpopulations were submitted to adhesion and migration assays on laminin and fibronectin (crucial proteins to invasion and metastasis), as well as to anchorage-independent growth. Two morphologically different subpopulations were isolated: LISP-A10 and LISP-E11. LISP-A10 presents a differentiated epithelial pattern, and LISP-E11 is fibroblastoid, suggesting a poorly differentiated pattern. LISP-A10 expressed the two intercellular adhesion molecules tested, carcinoembryonic antigen (CEA) and desmoglein, while LISP-E11 expressed only low amounts of CEA. On the other hand, adhesion to laminin and fibronectin as well as migration towards these extracellular matrix proteins were higher in LISP-E11, as expected from its poorly differentiated phenotype. Both subpopulations showed anchorage-independent growth on a semi-solid substrate. These results raise the possibility that the heterogeneity found in the LISP-I cell line, which might have contributed to its ability to metastasize, was due to at least two different subpopulations herein identified.
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    Lectin KM+-induced neutrophil haptotaxis involves binding to laminin
    (Elsevier B.V., 2005-01-18) Ganiko, L.; Martins, A. R.; Freymuller, E.; Mortara, R. A.; Roque-Barreira, M. C.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP)
    The lectin KM+ from Artocarpus integrifolia, also known as artocarpin, induces neutrophil migration by haptotaxis. the interactions of KM+ with both the extracellular matrix (ECM) and neutrophils depend on the lectin ability to recognize mannose-containing glycans. Here, we report the binding of KM+ to laminin and demonstrate that this interaction potentiates the KM+-induced neutrophil migration. Labeling of lung tissue by KM+ located its ligands on the endothelial cells, in the basement membrane, in the alveolus, and in the interstitial connective tissue. Such labeling was inhibited by 400 mM D-mannose, 10 mM Manalpha1-3[Manalpha1-6]Man or 10 muM peroxidase (a glycoprotein-containing mannosyl heptasaccharide). Laminin is a tissue ligand for KM+, since both KM+ and anti-laminin antibodies not only reacted with the same high molecular mass components of a lung extract, but also determined colocalized labeling in basement membranes of the lung tissue. the relevance of the KM+-laminin interaction to the KM+ property of inducing neutrophil migration was evaluated. the inability of low concentrations of soluble KM+ to induce human neutrophil migration was reversed by coating the microchamber filter with laminin. So, the interaction of KM+ with laminin promotes the formation of a substrate-bound KM+ gradient that is able to induce neutrophil haptotaxis. (C) 2004 Elsevier B.V. All rights reserved.
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    Modeling the Trypanosoma cruzi Tc85-11 protein and mapping the laminin-binding site
    (Elsevier B.V., 2004-12-10) Marroquin-Quelopana, M.; Oyama, S.; Pertinhez, T. A.; Spisni, A.; Juliano, M. A.; Juliano, L.; Colli, W.; Alves, MJM; Universidade de São Paulo (USP); Lab Nacl Luz Sincrotron; Univ Parma; Universidade Federal de São Paulo (UNIFESP)
    Trypanosoma cruzi expresses a set of glycoproteins encoded by the gp85/trans-sialidase gene superfamily. in this report a structure model is proposed for a cloned member of the superfamily, the Tc85-11 protein. the structure consists of an N-terminus beta-propeller and a C-terminus beta-sandwich interconnected by an alpha-helix, the recombinant protein, corresponding to the N-domain (Tc85-N), binds to laminin in a selective manner. Six synthetic 20-mer peptides from the N-domain adhere onto the surface of LLC-MK2 cells and two of these peptides specifically inhibit the Tc85-N/laminin interaction, indicating that they are the laminin-binding sites of the molecule. Thus, Tc85-11 and other related members of the family appear to be good candidates to play an important role in T cruzi infection via a laminin mediated host-parasite interaction. (C) 2004 Elsevier Inc. All rights reserved.
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    The predictive value of serum laminin for the risk of variceal bleeding related to portal pressure levels
    (H G E Update Medical Publ Ltd., 1995-09-01) Kondo, M.; Miszputen, Sender Jankiel [UNIFESP]; LeiteMor, MBM; Parise, Edison Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Background/Aims: This paper presents the results of the radioimmunologic determination of laminin, in serum of patients with alcoholic liver cirrhosis with a preserved hepatic function, trying to evaluate its predictive value for the risk of variceal bleeding, assessed by a portal pressure level equal to or higher than 12 mmHg (7).Patients and Methods: Twenty alcoholic cirrhotic patients with a preserved hepatic function as assessed by the Child-Pugh classification, had their peripheral blood taken for radioimmunological determination of serum laminin and were submitted to hepatic vein catheterization, for portal pressure measurement.Results: A positive and significant correlation (r=0.70, p<0.001) was found between serum laminin Levels (mean value+SD=2.70+1.13 U/ml) and hepatic vein pressure gradient (mean HVPG+SD=16.30+6.06 mmHg). Such correlation prompted us to find a value for the level of laminin that more closely represented a HVPG of 12 mmHg, a well known threshold pressure for esophageal varices bleeding. At a cut-off concentration, for laminin of 2.19 U/ml, sensitivity was 73%, specificity 60%, the positive predictive value was 85% and the negative predictive value 43%. In this study population with a prevalence of 75% of a HVPG greater than or equal to 12 mmHg, the diagnostic accuracy for such levels of serum laminin was 70%.Conclusions: Although a valid attempt in having a hypertension, peripheral serum laminin alone doesn't hypertension and to assess the risk of variceal bleeding in patients with alcoholic cirrhosis.