Navegando por Palavras-chave "Laminin"

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    Cytotoxic activity and degradation patterns of structural proteins by corneal isolates of Acanthamoeba spp
    (Springer, 2015-01-01) Sant'ana, Viviane Peracini [UNIFESP]; Carrijo-Carvalho, Linda Christian [UNIFESP]; Foronda, Annette Silva [UNIFESP]; Chudzinski-Tavassi, Ana Marisa; Freitas, Denise de [UNIFESP]; Souza de Carvalho, Fabio Ramos [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Butantan Inst
    Proteolytic enzymes secreted by trophozoites (amoebic secretome) are suggested as the main virulence factor involved in the severity of Acanthamoeba keratitis. the degradation profile of the main glycoprotein components of anterior and posterior portions of the cornea and the cytopathic effect of secretomes on endothelial cells by contact-independent mechanism were evaluated.Trophozoites were isolated primarily from corneal tissue samples (n = 11) and extracellular proteins were collected from axenic cell culture supernatants. the molecular weights of proteolytic enzymes were estimated by zymography. Enzymatic cleavage of laminin and fibronectin substrates by amoebic secretome was investigated and cluster analysis was applied to the proteolysis profiles. Primary cultures of endothelial cells were used in both qualitative and quantitative assays of cytophatogenicity.Differential patterns of proteolysis were observed among the Acanthamoeba secretomes that were analysed. the uniformity of laminin degradation contrasted with the diversity of the proteolysis profiles observed in the fibronectin substrate. Acanthamoeba secretome extracted from four clinical isolates was shown to be toxic when in contact with the endothelial cell monolayer (p < 0.01). Induction of apoptosis and membrane permeability, at different percentual values, were suggested as the main mechanisms that could induce endothelial cell death when in contact with amoebic secretome.Our results provide evidence that virulence factors secreted by Acanthamoeba trophozoites can be related to an increased pathogenicity pattern by an independent contact-trophozoite mechanism, through induction of endothelial cell death by apoptosis at a higher percentage than providing the lack of cell viability by the membrane-associated pore-forming toxin activity.
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    Elevação dos níveis séricos de laminina na cirrose hepática induzida pelo tetracloreto de carbono
    (Instituto Brasileiro de Estudos e Pesquisas de Gastroenterologia - IBEPEGE Colégio Brasileiro de Cirurgia Digestiva - CBCD Sociedade Brasileira de Motilidade Digestiva - SBMD Federação Brasileira de Gastroenterologia - FBGSociedade Brasileira de Hepatologia - SBHSociedade Brasileira de Endoscopia Digestiva - SOBED, 2003-09-01) Neves, Lindalva Batista [UNIFESP]; Catarino, Regina Maria [UNIFESP]; Silva, Maria Regina Regis [UNIFESP]; Parise, Edison Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    BACKGROUND: Serum laminin has been correlated with portal hypertension and sinusoid capillarization in chronic liver diseases. Little is known about its dynamics in liver diseases. AIM: To investigate the levels of serum laminin in experimental cirrhosis induced by carbon tetrachloride, as well as to correlate its level with the degree of hepatic fibrosis and portal hypertension. MATERIAL AND METHODS: Forty-nine albino Wistar rats were studied. Twenty-three were treated with carbon tetrachloride solution at 8% and 16 were kept as controls. Between the 6th and 16th weeks, all animals were sacrificed, submitted to measurement of portal pressure and blood sampling of the femoral veins. Liver fragments were fixed for light microscopic studies. Hepatic fibrosis was classified as perivenular fibrosis, complete and incomplete septal fibrosis and cirrhosis. Determination of laminin concentration was performed by ELISA with an antibody against laminin isolated from Engelbreth-Holm-Swarm tumor. RESULTS: The portal pressure was correlated with the degree of hepatic fibrosis (rs = 0.82; n = 45). Its levels in septal fibrosis (10.8 ± 1.2 cm H(2)0) and cirrhosis (13.6 ± 3.1 cm H(2)0) were statistically higher when compared to control (7.9 ± 1.5 cm H20) and perivenular fibrosis (9.1 ± 0.8 cm H(2)0) groups. Peripheral blood laminin concentration in cirrhosis (40.0 ± 18.7 mg/dL) was significantly higher when compared to control (13.8 ± 12.1 mg/dL), perivenular fibrosis (19.1 ± 15.5 mg/dL) and septal fibrosis (22.2 ± 27.0 mg/dL) groups. The circulating laminin was correlated to the degree of hepatic fibrosis (rs = 0.59; n = 49) and to portal pressure (r = 0.29; n = 45). CONCLUSIONS: In the chronic carbon tetrachloride intoxication, laminin levels are better correlated with the development of hepatic fibrosis than with portal hypertension.
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    Expressão de moléculas da matriz extracelular em células endoteliais resistentes ao anoikis
    (Universidade Federal de São Paulo, 2016-04-19) Lopes, Silvana de Araujo [UNIFESP]; Azevedo, Carla Cristina Lopes de [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The extracellular matrix (ECM) is a structure composed of several macromolecules that are differently distributed among tissues of organisms. The interaction between ECM molecules and receptors present on the cell membrane affect several cell properties, including migration, proliferation, differentiation and apoptosis.The process of apoptosis by loss of cell adhesion is named anoikis. This process is considered an important mechanism in preventing independent growth of cell adhesion, because it difficult the binding of cells to inappropriate matrix, thus preventing the colonization of other tissues. However, resistance to anoikis is a critical step in tumor progression and metastasis.Because of the importance and complexity of cell-cell and cell-ECM interactions, studies on the ECM components have important relevance because it represents progress in the development of new drugs for the treatment of cancer.Thus, we studied the expression and localization of various ECM molecules in endothelial cells derived from rabbit aorta (EC), EC transfected with EJ-ras oncogene (EJ-ras EC) and EC resistant to anoikis (Adh1-EC e Adh2-EC).The results show that there was a decrease in the expression of fibronectin, collagen IV and hyaluronic acid as well as an increase in the expression of perlecam, laminin, integrinsαvβ3 and α5β1, MMPs-2 and -9 and hyaluronidases 1, 2 and 3 in anoikis resistant and transfected endothelial cells in relation to parental cells. These results suggest that changes in ECM molecules expression can be directly related to the acquisition of resistance to anoikis in endothelial cells.
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    Identification of enolase as a laminin-binding protein on the surface of Staphylococcus aureus
    (Elsevier B.V., 2004-05-01) Carneiro, Celia Regina Whitaker [UNIFESP]; Postol, Edilberto; Nomizo, Regina; Reis, Luiz Fernando Lima; Brentani, Ricardo Renzo; Hosp Canc AC Camargo; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Ludwig Inst Canc Res
    We have previously demonstrated that Staphylococcus aureus, a highly invasive bacteria, presents a 52-kDa surface protein that mediates its binding to laminin. in order to better characterize this receptor, we excised this putative laminin receptor from two-dimensional (2-D) PAGE and used it as antigen for raising a mouse hyperimmune serum which was for screening an S. aureus expression library. A single clone of 0.3 kb was obtained, and its sequence revealed 100% homology with S. aureus a-enolase. Moreover, amino acid sequencing of the 52-kDa protein eluted from the 2-D gel indicated its molecular homology with a-enolase, an enzyme that presents a high evolutionary conservation among species. in parallel, monoclonal antibodies raised against the S. aureus 52-kDa band also recognized yeast a-enolase in western blot analysis. These monoclonal antibodies were also able to promote capture of iodine-labeled bacteria when adsorbed to a solid phase, and this capture was inhibited by the addition of excess rabbit muscle a-enolase. Finally, the cell surface localization of S. aureus a-enolase was further confirmed by flow cytometry. Hence, a-enolase might play a critical role in the pathogenesis of S. aureus by allowing its adherence to laminin-containing extracellular matrix. (C) 2004 Elsevier SAS. All rights reserved.
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    Serum laminin, type IV collagen and hyaluronan as fibrosis markers in non-alcoholic fatty liver disease
    (Associação Brasileira de Divulgação Científica, 2005-05-01) Santos, V.n. dos [UNIFESP]; Leite-Mór, Marilisa Moraes Barros [UNIFESP]; Kondo, Mario [UNIFESP]; Martins, J.r. [UNIFESP]; Nader, Helena Bonciani [UNIFESP]; Lanzoni, Valeria Pereira [UNIFESP]; Parise, Edison Roberto [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    Hepatic fibrosis in patients with non-alcoholic fatty liver disease is associated with progression of the disease. In the present study, we analyzed the discriminative ability of serum laminin, type IV collagen and hyaluronan levels to predict the presence of fibrosis in these patients. In this preliminary report, we studied 30 overweight patients divided into two groups according to the absence (group I, N = 19) or presence (group II, N = 11) of fibrosis in a liver biopsy. Triglycerides, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltranspeptidade, hyaluronan (noncompetitive fluoroassay), type IV collagen, and laminin (ELISA) were determined. Group II presented significantly higher mean laminin, hyaluronan, type IV collagen, and aspartate aminotransferase values, which were due to the correlation between these parameters and the stage of fibrosis in the biopsy (Spearman's correlation coefficient, rS = 0.65, 0.62, 0.53, and 0.49, respectively). Analysis of the ROC curve showed that laminin values >282 ng/ml were those with the best diagnostic performance, with 87% accuracy. Association of laminin with type IV collagen showed improvement in the positive predictive value (100%), but with reduction in diagnostic sensitivity (64%). When compared with the criteria of Ratziu et al. [Gastroenterology (2000) 118: 1117-1123] for the diagnosis of septal fibrosis, laminin values presented a better diagnostic accuracy (83 vs 70%). Determination of extracellular matrix components in serum, especially of laminin, may identify patients with non-alcoholic fatty liver disease and fibrosis and these components may be used as indicators for liver biopsy in these patients.