Navegando por Palavras-chave "Dermatan sulfate"
Agora exibindo 1 - 5 de 5
Resultados por página
Opções de Ordenação
- ItemAcesso aberto (Open Access)Collagens and proteoglycans of the corneal extracellular matrix(Associação Brasileira de Divulgação Científica, 2003-08-01) Michelacci, Yara Maria [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)The cornea is a curved and transparent structure that provides the initial focusing of a light image into the eye. It consists of a central stroma that constitutes 90% of the corneal depth, covered anteriorly with epithelium and posteriorly with endothelium. Its transparency is the result of the regular spacing of collagen fibers with remarkably uniform diameter and interfibrillar space. Corneal collagen is composed of heterotypic fibrils consisting of type I and type V collagen molecules. The cornea also contains unusually high amounts of type VI collagen, which form microfibrillar structures, FACIT collagens (XII and XIV), and other nonfibrillar collagens (XIII and XVIII). FACIT collagens and other molecules, such as leucine-rich repeat proteoglycans, play important roles in modifying the structure and function of collagen fibrils.Proteoglycans are macromolecules composed of a protein core with covalently linked glycosaminoglycan side chains. Four leucine-rich repeat proteoglycans are present in the extracellular matrix of corneal stroma: decorin, lumican, mimecan and keratocan. The first is a dermatan sulfate proteoglycan, and the other three are keratan sulfate proteoglycans. Experimental evidence indicates that the keratan sulfate proteoglycans are involved in the regulation of collagen fibril diameter, and dermatan sulfate proteoglycan participates in the control of interfibrillar spacing and in the lamellar adhesion properties of corneal collagens. Heparan sulfate proteoglycans are minor components of the cornea, and are synthesized mainly by epithelial cells. The effect of injuries on proteoglycan synthesis is discussed.
- ItemAcesso aberto (Open Access)Estudo bioquímico do glicosaminoglicano dermatam sulfato em homens adultos portadores de hérnia inguinal tipo II de Nyhus(Colégio Brasileiro de Cirurgiões, 2011-06-01) Silva, Evandro de Moraes e; Lopes Filho, Gaspar de Jesus [UNIFESP]; Nader, Helena Bonciani [UNIFESP]; Gonçalves, Rogério de Oliveira [UNIFESP]; Kobayashi, Elza Yoko [UNIFESP]; Dreyfuss, Juliana Luporini [UNIFESP]; UNIFOA; Universidade Federal de São Paulo (UNIFESP)OBJECTIVE: To compare the amount of the dermatan sulfate glycosaminoglycan between male patients with Nyhus type II inguinal hernias and subjects without inguinal hernia, aged between 20 and 40 years. METHODS: Two groups were formed: One with 15 male patients with Nyhus type II inguinal hernia and aged between 20 and 40 years with ASA risk I and II, and a control group of ten individuals, also males between 20 and 40, who had died up to 24 h before. We excluded female patients, diabetic patients with connective tissue disease, smokers and surgical risk ASA III and IV. We resected a sample of 1 cm² of the transversalis fascia in the middle of the inguinal trigone, and 1 cm² of the anterior sheath of the rectus abdominis muscle in the groin for the quantification of dermatan sulfate glycosaminoglycans by densitometry after agarose gel electrophoresis. RESULTS: The amount of dermatan sulfate showed no statistically significant difference between patients with inguinal hernia and individuals without inguinal hernia in both the transverse fascia (p = 0.108) and anterior sheath of the rectus abdominis muscle (p = 0.292). CONCLUSION: There was no difference in the amount of the dermatan sulfate glycosaminoglycan among patients with Nyhus type II inguinal hernias and subjects without inguinal hernia in adult males.
- ItemSomente MetadadadosEvaluation of glycosaminoglycans and heparanase in placentas of women with preeclampsia(Elsevier B.V., 2014-11-01) Brosco Fama, Eduardo Augusto; Souza, Renan Salvioni; Melo, Carina Mucciolo [UNIFESP]; Pompei, Luciano Melo; Silva Pinhal, Maria Aparecida [UNIFESP]; FMABC; Universidade Federal de São Paulo (UNIFESP)Background: Preedampsia is a multisystem disorder whose etiology remains unclear. It is already known that circulation of soluble fms-like tyrosine kinase-1 (sFlt-1) is directly involved in pre-eclampsia development. However, the molecular mechanisms involved with sFlt-1 shedding are still unidentified. We identified, quantified glycosaminoglycans and determined the enzymatic activity of heparanase in placentas of women with preeclampsia, in order to possibly explain if these compounds could be related to cellular processes involved with preeclampsia.Methods:A total of 45 samples collected from placentas, 15 samples from placentas of preeclampsia women and 30 samples from non-affected women. Heparan sulfate and dermatan sulfate were identified and quantified by agarose gel electrophoresis, whilst hyaluronic acid was quantified by an ELISA like assay. Heparanase activity was determined using biotynilated heparan sulfate as substrate.Results: the results showed that dermatan sulfate (P = 0.019), heparan sulfate levels (P = 0.015) and heparanase activity (P = 0.006) in preeclampsia were significantly higher than in the control group. There was no significant difference between the groups for hyaluronic acid expression in placentas (P = 0.110). the present study is the first to demonstrate directly the increase of heparan sulfate in human placentas from patients with preeclampsia, suggesting that endogenous heparan sulfate could be involved in the release of sFlt-1 from placenta, increasing the level of circulating sFlt-1.Conclusion: Alterations of extracellular matrix components in placentas with preeclampsia raise the possibility that heparan sulfate released by heparanase is involved in mechanisms of preeclampsia development. Published by Elsevier B.V.
- ItemAcesso aberto (Open Access)Glycosaminoglycan distribution in the rat uterine cervix during the estrous cycle(Faculdade de Medicina / USP, 2010-01-01) Cubas, Jairo Jose Matozinho [UNIFESP]; Simões, Ricardo Santos; Oliveira-Filho, Ricardo Martins; Simões, Manuel de Jesus [UNIFESP]; Baracat, Edmund Chada [UNIFESP]; Soares-Junior, José Maria [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)OBJECTIVE: To analyze the amount of glycosaminoglycans in the uterine cervix during each phase of the rat estrous cycle. DESIGN: Based on vaginal smears, forty female, regularly cycling rats were divided into four groups (n = 10 for each group): GI - proestrous, GII - estrous, GIII - metaestrous and GIV - diestrous. Animals were sacrificed at each phase of the cycle, and the cervix was immediately removed and submitted to biochemical extraction and determination of sulfated glycosaminoglycans and hyaluronic acid. The results were analyzed by ANOVA followed by the Bonferroni post-hoc test. RESULTS: The uterine cervix had the highest amount of total sulfated glycosaminoglycans and dermatan sulfate during the estrous phase (8.90 ± 0.55 mg/g of cetonic extract, p<0.001; and 8.86 ± 0.57 mg/g of cetonic extract, p<0.001). In addition, there was more heparan sulfate at the cervix during the proestrous phase (0.185 ± 0.03 mg/g of cetonic extract) than during any other phase (p<0.001). There were no significant changes in the concentration of hyaluronic acid in the uterine cervix during the estrous cycle. CONCLUSION: Our data suggest that the amount of total sulfated glycosaminoglycans may be influenced by hormonal fluctuations related to the estrous cycle, with dermatan sulfate and heparan sulfate being the glycosaminoglycans most sensitive to hormonal change.
- ItemAcesso aberto (Open Access)Heparan sulfate mediates trastuzumab effect in breast cancer cells(Biomed Central Ltd, 2013-10-01) Suarez, Eloah Rabello [UNIFESP]; Paredes-Gamero, Edgar Julian [UNIFESP]; Del Giglio, Auro; Tersariol, Ivarne Luis dos Santos [UNIFESP]; Nader, Helena Bonciani [UNIFESP]; Pinhal, Maria Aparecida Silva [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Fac Med ABCBackground: Trastuzumab is an antibody widely used in the treatment of breast cancer cases that test positive for the human epidermal growth factor receptor 2 (HER2). Many patients, however, become resistant to this antibody, whose resistance has become a major focus in breast cancer research. But despite this interest, there are still no reliable markers that can be used to identify resistant patients. A possible role of several extracellular matrix (ECM) components-heparan sulfate (HS), Syn-1(Syndecan-1) and heparanase (HPSE1)-in light of the influence of ECM alterations on the action of several compounds on the cells and cancer development, was therefore investigated in breast cancer cell resistance to trastuzumab.Methods: the cDNA of the enzyme responsible for cleaving HS chains from proteoglycans, HPSE1, was cloned in the pEGFP-N1 plasmid and transfected into a breast cancer cell lineage. We evaluated cell viability after trastuzumab treatment using different breast cancer cell lines. Trastuzumab and HS interaction was investigated by confocal microscopy and Fluorescence Resonance Energy Transfer (FRET). the profile of sulfated glycosaminoglycans was also investigated by [S-35]-sulfate incorporation. Quantitative RT-PCR and immunofluorescence were used to evaluate HPSE1, HER2 and Syn-1 mRNA expression. HPSE1 enzymatic activity was performed using biotinylated heparan sulfate.Results: Breast cancer cell lines responsive to trastuzumab present higher amounts of HER2, Syn-1 and HS on the cell surface, but lower levels of secreted HS. Trastuzumab and HS interaction was proven by FRET analysis. the addition of anti-HS to the cells or heparin to the culture medium induced resistance to trastuzumab in breast cancer cells previously sensitive to this monoclonal antibody. Breast cancer cells transfected with HPSE1 became resistant to trastuzumab, showing lower levels of HER2, Syn-1 and HS on the cell surface. in addition, HS shedding was increased significantly in these resistant cells.Conclusion: Trastuzumab action is dependent on the availability of heparan sulfate on the surface of breast cancer cells. Furthermore, our data suggest that high levels of heparan sulfate shed to the medium are able to capture trastuzumab, blocking the antibody action mediated by HER2. in addition to HER2 levels, heparan sulfate synthesis and shedding determine breast cancer cell susceptibility to trastuzumab.