• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 33
  • 6
  • 4
  • 2
  • 2
  • 1
  • 1
  • 1
  • Tagged with
  • 56
  • 27
  • 14
  • 10
  • 7
  • 7
  • 6
  • 6
  • 6
  • 6
  • 5
  • 5
  • 5
  • 5
  • 5
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Endothelin converting and degrading enzymes

Kaw, Semiko January 1993 (has links)
No description available.
2

Theoretical Insight into Mechanisms of Natural and Artificial Metalloproteases

Li, Shanghao 22 June 2011 (has links)
In this study, theoretical and computational approaches have been utilized to investigate the mechanisms of natural and artificial metalloproteases. The active sites of most natural metalloproteases contain a tetrahedral zinc center, coordinated by three amino acid residues combinated from His(N), Cys(S), Glu(O), and Asp(O) with a water molecule as the fourth ligand. However, the roles played by the ligands environment in the catalytic functions of enzyme are not clear. In this study, the effects of different ligand combinations (NS2, N2S, N2O, N3, S3, NO2 and NSO) in the mechanism were investigated energy barriers were compared. The machanism and energetics of the substrate bound artificial metalloproteases Ni(II)cyclen (cyclen: 1,4,7,10-tetraazacyclododecane) and Cd(II)cyclen have been investigated. In addition, the mechanism of hydrolysis of Phe-Phe peptide bond catalyzed by another artificial metalloprotease [Pd(H2O)4]2+ has also been studied.
3

Biochemical Investigation of Progeroid Disease-Associated Mutations in Human ZMPSTE24

Erh-Ting Hsu (5929769) 17 January 2019 (has links)
<p>ZMPSTE24 is a unique intramembrane zinc metalloprotease that plays critical roles in the lamin A maturation pathway. Lamin A comprises a dense network underlying the inner nuclear membrane that maintains the structural integrity and proper function of the nucleus. The precursor of lamin A, prelamin A, terminates with a CAAX motif, where “C” is cysteine, “A” is typically an aliphatic amino acid, and “X” is one of several different amino acids. Like all CAAX proteins, prelamin A undergoes a series of post-translational modifications, including farnesylation of the cysteine by farnesyltransferase, endoproteolysis of the AAX residues by ZMPSTE24 or possibly a related protease RCE1, and carboxyl methylation by isoprenylcysteine carboxyl methyltransferase (ICMT). After CAAX processing, an additional cleavage event by ZMPSTE24 occurs to remove 15 residues from the C-terminus, including the farnasylated and carboxyl methylated cysteine, releasing mature lamin A into the nucleoplasm. Mutations in the gene encoding ZMPSTE24 that impair proteolytic activity cause a set of progeroid diseases, including B-type mandibuloacral dysplasia (MAD-B) and restrictive dermopathy (RD). Recently, ZMPSTE24 mutations were also detected in patients with metabolic syndrome (MS) and nonalcoholic fatty liver disease (NAFLD). Patients with these diseases have shown defective prelamin A processing, leading to the accumulation of persistently farnesylated prelamin A in the nucleus. However, how this accumulation causes disease remains unclear. We demonstrated that both ZMPSTE24 and another known CAAX protease, RCE1 are both capable of mediating the C-terminal cleavage of prelamin A. RCE1 retains the capacity to cleave the AAX residues of prelamin A in progeroid diseases induced by inactive ZMPSTE24 mutants, therefore the disease molecule will be most likely farnesylated and methylated prelamin A. These factors suggest that the ability of ZMPSTE24 to perform the upstream cleavage determines the accumulation level of uncleaved prelamin A in progeroid diseases. However, there was no available assay that could quantitatively demonstrate the <i>in vitro</i> upstream cleavage activity of ZMPSTE24. Therefore, we first developed a FRET-based assay that was able to precisely quantify the upstream cleavage activity of Ste24, the yeast homolog of ZMPSTE24. The 33-mer analog of <b>a</b>-factor, Ste24 natural substrate, has a 2-aminobenzoic acid (Abz) fluorophore at the N-terminus and a dinitophenol (Dnp) quencher located on the either side of the proposed cleavage site. After cleavage, quantification of the fluorescence from the dequenced peptide enabled us to continuously monitor the upstream cleavage activity of Ste24. We then utilized this FRET-based assay to examine the upstream cleavage activity of wild-type ZMPSTE24 and its disease mutants. We demonstrated that the <b>a</b>-factor analog FRET substrate could be recognized and cleaved at the predicted position by ZMPSTE24. Disease variants were examined using this assay and the results revealed reduced upstream cleavage activity. Moreover, blocking ubiquitylation restored catalytic activity of some ZMPSTE24 disease variants, suggesting that diminished activity of these mutants is due to protein instability. Limited trypsin digestion results also indicated that some variants may not be properly folded, as compared to wild-type. The crystal structure of ZMPSTE24 revealed that seven transmembrane helices of ZMPSTE24 surround a large intramembrane chamber. The HEXXH zinc metalloprotease motif faces inward to cap the top of the chamber inside which proteolysis is proposed to occur. The four side portals apparent in the structure may provide substrate entry and exit routes. Based on structural considerations, besides interfering with structural integrity, these disease mutations may decrease ZMPSTE24 activity by preventing substrate binding in the active site or occluding substrate entry into or exit from the enzyme chamber. Using a yeast <b>a</b>-factor sequence-based photoactive analog containing benzophenone in the farnesyl portion, which can be well processed by ZMPSTE24, we have shown that certain disease mutants may affect farnesyl binding of the C-terminal cleavage substrate. We also designed several double cysteine mutants near portal 1 in Cys-less background of Ste24. We then utilized bismaleimide sulfhydryl-to-sulfhydryl crosslinkers to block the portal opening. Some of the crosslinked double mutants showed reduced AAX cleavage activity, suggesting the portal 1 may be important for the C-terminal cleavage. Together, these data will clarify how the enzyme functions and also provide further insights into progeroid diseases.</p>
4

Etude de l'effet des modulations de l'expression des métalloprotéases et de leurs inhibiteurs dans la réaction bronchique aux aéroallergènes.

Guéders, Maud 17 April 2008 (has links)
Lasthme est une pathologie inflammatoire caractérisée par une inflammation, une hyperréactivité et un remodelage bronchique. Des études menées sur des souris déficientes en MMP-8 et en MMP-19 nous ont permis de démontrer que ces deux protéases jouaient un rôle protecteur vis-à-vis du développement de l'inflammation dans la pathologie asthmatique. En effet, suite à la sensibilisation et à l'exposition par inhalation à lallergène (Ovalbumine),les souris déficientes en MMP-8 en MMP-19 développent respectivement une inflammation neutrophilique et éosinophilique significativement plus importante comparativement aux souris wild-type. Dans une seconde partie de ce travail, nous avons évalué les effets de deux inhibiteurs synthétiques des MMPs administrés en inhalation sous une formulation adéquate dans notre modèle murin dasthme. Suite à ladministration de ces deux inhibiteurs, nous avons observé une diminution de linflammation au sein du lavage bronchoalvéolaire. De plus, nous observons une diminution de linfiltration du tissu pulmonaire par les cellules inflammatoires. Lhyperréactivité bronchique observée suite à linhalation de doses croissantes de méthacholine est également significativement diminuée. Ces résultats sont comparables à ceux obtenus après linhalation de Fluticasone, stéroïde inhalé utilisé très largement en clinique humaine et utilisé dans nos expériences comme médicament de référence. Afin dobserver les modifications morphologiques bronchiques, nous avons mis au point un modèle murin dasthme permettant une exposition de longue durée (90 jours) aux allergènes. En plus de développer une inflammation pulmonaire, les souris traitées vont voir la structure de leurs bronches se modifier. L'inhalation de doxycycline diminue significativement l'inflammation, la réactivité bronchique et diverses caractéristiques du remodelage bronchique telles que l'hyperplasie des cellules à mucus, le dépôt de collagène péribronchique, l'épaisseur de la membrane basale sous-épithéliale et l'épaisseur de la couche de cellules musculaires lisses. Au cours de ces travaux, nous avons caractérisé des modèles murins dasthme. Nous avons démontré que linhibition de certaines MMPs est délétère, nous incitant à les considérer comme des « anti targets ». Nous avons, dans une seconde partie, pu apporter la démonstration que linhibition de certaines MMPs précises (MMP-2, -9 et -14) par des inhibiteurs relativement spécifiques administrés en inhalation améliore le phénotype asthmatique. Par ces travaux, nous avons contribué à la compréhension globale des mécanismes impliquant les MMPs dans la pathologie asthmatique et nous suggérons que de nouvelles voies thérapeutiques, basées sur linhibition de certaines MMPs, pourraient faire lobjet de développements futurs.
5

LIM KINASE 1 MODULATES EXPRESSION OF MATRIX METALLOPROTEINASES AND ASSOCIATES WITH GAMMA-TUBULIN: DUAL ROLE IN INVASION AND MITO

Tapia, Tenekua 18 September 2007 (has links)
LIM kinase 1 (LIMK1) is a unique dual specificity serine/threonine kinase containing two N-terminal LIM domains in tandem, a PDZ domain and a C-terminal catalytic domain. LIMK1 is involved in modulation of actin cytoskeleton through inactivating phosphorylation of the ADF (actin depolymerization factor) family protein cofilin. Recent studies have shown that LIMK1 is upregulated in breast and prostate cancer cells and tissues, promotes metastasis in animals and induces acquisition of an invasive phenotype when ectopically expressed in benign prostate epithelial (BPH) cells. Furthermore, overexpression of LIMK1 was associated with altered sub cellular localization of the membrane type 1 matrix metalloprotease (MT1-MMP). Matrix metalloproteases (MMPs) are a family of zinc dependant proteolytic enzymes that hydrolyze extra cellular matrix and cell surface molecules. A number of MMPs including MMP-2, MMP-9 and their activator MT1-MMP are over expressed in a variety of cancers including prostate cancer. The abundant expression of these enzymes contributes to changes in the tumor microenvironment, which facilitate degradation of the surrounding collagen matrix and migration of cells through the matrix defects. In this study, we show that MMPs are involved in LIMK1 induced invasion of otherwise non-invasive BPH cells. We also show that (a) the kinase activity of LIMK is not essential for the invasive behavior of the cells and (b) the absence of LIM domains significantly retards cell invasion. We have established transfected sub lines of BPH cells stably expressing 1) constitutively active LIMK1 (BPHLCA), 2) kinase dead LIMK1 (BPHLKD) and 3) only the kinase domain of LIMK1 (BPHLK) for our study. In vitro invasion assays revealed that LIMK1 induced invasion was inhibited by the MMP specific inhibitor, GM6001, and that cells expressing kinase-dead LIMK1 were equally invasive. Furthermore, BPH cells expressing LIMK1 mutants expressed higher amounts of MMP-2 and MMP-9. Substrate zymography revealed increased concentration of secreted MMP-2 and MMP-9 in the media of BPHLCA and BPHLK cells respectively compared to BPHV (vector control) cells. Quantitative RT-PCR also showed a ~10 fold increase in the steady state concentration of MMP-2 in BPHLCA cells compared to the control BPHLV cells. Expression of active LIMK1 stimulated cell-surface expression of MT1-MMP in BPHLCA cells as determined by flow cytometry. A modest increase in expression of MT1-MMP was noted in BPHLKD cells compared to BPHLK and BPHV cells. Immunoflourescence analysis indicated differential localization of MT1-MMP and LIMK1 in BPH cells expressing different mutants of LIMK1. Co-localization of LIMK1 and MT1-MMP in the plasma membrane and in the perinuclear region was also evident in these cells. Furthermore, here we provide evidence that suggests a functional role for phosphorylated (activated) LIMK1/2 (p-LIMK1/2) during mitosis through its association with &#947;-tubulin. Immunoflourescence analysis showed distinct co-localization of &#947; -tubulin and p-LIMK1/2 in the centrosomes during mitosis from early prophase to the beginning of telophase. No association was seen in the interphase or in late telophase. Phospho-LIMK1/2 was co-precipitated in immunoprecipitates of &#947; -tubulin using an anti- &#947; -tubulin antibody suggesting a physical association between these proteins in a complex. This finding reveals a novel role of LIMK1 in the mitotic process. In summary, our data suggests that MMPs are involved in LIMK1 induced invasion of prostate epithelial cells, and that this effect is mediated through altered expression and activation of specific MMPs. Furthermore, LIMK1 induced invasion is dependant on the presence of LIM domains more than the kinase activity. Finally, we show that phosphorylated LIMK1 and LIMK2 are involved in the mitotic process in a stage specific manner through its association with the centrosomal protein &#947; -tubulin. Because LIMK1 promotes invasion in vitro, regulates expression of MMPs, and is involved in mitotic processes, it is an attractive drug target for prostate cancer therapy. / M.S. / Department of Molecular Biology and Microbiology / Burnett College of Biomedical Sciences / Molecular and Microbiology MS
6

Functional characterization of the Cydia pomonella granulovirus matrix metalloprotease

Ishimwe, Egide January 1900 (has links)
Master of Science / Department of Biology / A. Lorena Passarelli / Cydia pomonella granulovirus (CpGV) is a member of the Baculoviridae family of viruses. The CpGV open reading frame 46 (CpGV-ORF46) predicts a 545 amino acid protein that shares homology with matrix metalloproteases (MMPs), a family of zinc-dependent endopeptidases that degrade extracellular matrix proteins. In silico analyses revealed the presence of putative mmp genes in all species from the Betabaculovirus genus, while no mmps were identified in members of the Alphabaculovirus, Gammabaculovirus or Deltabaculovirus genera. Unlike most cellular MMPs, baculovirus MMPs do not have a propeptide domain, a domain involved in regulating MMP activation, or a hemopexin-like domain, which is necessary for substrate binding and specificity in many MMPs. However, Betabaculovirus MMPs do contain a predicted conserved zinc-binding motif (HEXGHXXGXXHS/T) within their catalytic domain. The function of CpGV-MMP and its effects on baculovirus replication in cultured cells and insect larvae were investigated. CpGV-MMP was expressed in and purified from Escherichia coli, and activity was measured using a generic MMP substrate in vitro. CpGV-MMP had in vitro activity and its activity was specifically inhibited by MMP inhibitors. To study the effects of CpGV-MMP on virus replication and dissemination, CpGV-MMP was expressed from Autographa californica nucleopolyhedrovirus (AcMNPV) under the control of a strong and constitutive promoter, the Drosophila heat shock 70 protein promoter. Expression of CpGV-MMP did not affect virus replication in cultured cells. The effects of expressing CpGV-MMP from AcMNPV during larval infection were evaluated in the presence or absence of the AcMNPV chitinase and cathepsin genes. Insect bioassays showed that the absence of cathepsin resulted in a significant delay in larval time of death; however, this delay was compensated by expression of CpGV-MMP. In addition, larval time of death was accelerated when cathepsin, chitinase, and CpGV-MMP were all expressed. Finally, we determined the effects of CpGV-MMP on larvae melanization and liquefaction. CpGV-MMP was able to promote larvae melanization in the absence of cathepsin. CpGV-MMP, in the absence of cathepsin, was not able to promote larvae liquefaction. When chitinase was engineered to be secreted from cells, CpGV-MMP rescued liquefaction in the absence of cathepsin. In conclusion, CpGV-MMP is a functional MMP which can enhance larvae mortality with the presence of cathepsin. In addition, CpGV-MMP can promote larvae melanization; however, it can only promote liquefaction when chitinase is engineered to be secreted from cells.
7

Caracterização biológica e molecular de cepas de Trypanosoma cruzi Chagas, 1909 (Kinetoplastida, Trypanosomatidae) isoladas da Bahia, Rio Grande do Sul, Santa Catarina e São Paulo / Biological and molecular characterization of strains of Trypanosoma cruzi Chagas, 1909 (Kinetoplastida, Trypanosomatidae) isolated from Bahia, Rio Grande do Sul, Santa Catarina and São Paulo

Ribeiro, Aline Rimoldi, 1980- 12 January 2014 (has links)
Orientadores: João Aristeu da Rosa, Mário Steindel / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-27T12:48:03Z (GMT). No. of bitstreams: 1 Ribeiro_AlineRimoldi_D.pdf: 21726449 bytes, checksum: 28ac88cc86cc90e738eb70f9dca45f0b (MD5) Previous issue date: 2014 / Resumo: Trypanosoma cruzi, protozoário que faz parte da família Trypanosomatidae é o agente causador da doença de Chagas que afeta 6-8 milhões de pessoas na América Latina. A origem dessa família pode ser estudada por meio de técnicas moleculares, como a investigação da região V7V8 - SSUrRNA. Trypanosoma cruzi é subdividido em seis grupos independentes TcI-TcVI denominados Unidades Discretas de Tipagem (DTUs). A caracterização biológica e molecular de onze cepas de T. cruzi pertencentes aos grupos TcI (Bolívia; Tlenti; Tmelanocephala; SC90), TcII (Famema; SC96; SI8; Y) e TcIII (QMM3; QMM5; SI5) isoladas de cinco espécies de triatomíneos esclarece fatores biológicos por parâmetros como a cinética de crescimento, curva parasitêmica, taxa de infeção celular, caracterização molecular, ação de metaloproteinases, perfil protéico e sorologia. O objetivo do trabalho foi a caracterização biológica e molecular de cepas de T. cruzi isoladas de triatomíneos da Bahia, Rio Grande do Sul, Santa Catarina e São Paulo. O grupo TcII de T. cruzi mostrou maior capacidade multiplicativa em formas epimastigotas durante a cinética de crescimento, seguido por TcI e TcIII. A curva parasitêmica evidenciou variabilidade entre os camundongos Balb/c, contudo ao comparar os grupos TcI, TcII e TcIII de T. cruzi o perfil parasitêmico mostrou-se equivalente. Acrescentando os dados biológicos estudou-se a taxa de infecção de T. cruzi em linhagens celulares J774 e macrófagos peritoneais. O grupo TcI de T. cruzi apresentou maior taxa de infecção e menor tempo exigido para a multiplicação de formas amastigotas, assim como macrófagos peritoneias mostraram-se mais atrativos para T. cruzi. A caracterização molecular, por meio da região V7V8, mostrou que essas cepas pertencem às DTUs TcI, TcII e TcIII. A separação dos grupos torna-se evidente ao comparar o perfil protéico em formas epi e tripomastigotas de T. cruzi. O grupo TcI apresentou mais proteínas nos géis de acrilamida, particularidade que pode ser associada a intra-específicidade de TcI. A ação de metaloproteinases foi observada em formas epi e tripomastigotas sugerindo presença ativa e estável durante parte do ciclo do parasito. A reatividade sorológica foi comprovada nos grupos TcI, TcII e TcIII, por meio de ELISA em diluições de 1/100 até 1/12.800. A adição da técnica de Western Blotting aos ensaios por SDS-PAGE em soros de animais infectados após 50 dias mostrou o perfil protéico da cepa Y em membrana de nitrocelulose. Em conjunto, os resultados mostraram que as onze cepas de T. cruzi apresentaram diferenças entre os grupos do parasito. O grupo TcI mostrou maior taxa de infecção em células; TcII, os maiores valores para a cinética de crescimento e TcIII filogenéticamente próximo a TcV, grupo híbrido. A associação parasito-hospedeiro pode explicar diferenças biológicas e moleculares em cepas de T. cruzi, neste sentido o estudo de onze cepas isoladas de diferentes hospedeiros pode agregar informações a literatura e esclarecer alguns aspectos biológicos desse patógeno / Abstract: Trypanosoma cruzi, a protozoan from the family Trypanosomatidae, is responsible for Chagas disease which affects about 6 to 8 million people in Latin America. The origin of this family can be studied through molecular techniques, for instance the investigation of the region V7V8 ¿ SSurRNA. The protozoan is subdivided in six independents groups TcI-TcVI known as Discrete Typing of Units (DTUs). The biological and molecular characterization of eleven strains of T. cruzi from the group TcI (Bolivia; Tlenti; Tmelanocephala; SC90), TcII (Famema; SC96; SI8; Y) and TcIII (QMM3; QMM5; SI5) isolated from five different species of triatomine are able to elucidate biological factors through the kinetic growth, parasitemic curve, cell infection rate, molecular characterization, metalloproteinase action, proteic and serological profile. This investigation was conducted to provide a biological and molecular characterization of T. cruzi isolated from specimens of triatomines. The group TcII of T. cruzi demonstrated higher replicative capacity in epimastigotes forms during the kinetic growth curve, followed by TcI and TcIII. The parasitemic curve demonstrated variability between Balb/c mice; however, the groups TcI, TcII and TcIII showed equivalent parasitemic profile. Furthermore, the cell infection rate in J774 cellular lineages and peritoneal macrophages was used to corroborate the biological data. The group TcI of T. cruzi demonstrated higher infection rate and less time to amastigotes forms multiplication and the peritoneal macrophages showed more attractive to T. cruzi. The molecular characterization through the V7V8 region indicated that these strains belong to DTUs TcI, TcII and TcIII. The groups segregation is important to compare the proteic profile of epimastigotes and tripomastigotes forms of T. cruzi. The groups TcI presented more proteins in acrylamide gels, which can be associated with intra-specif of TcI. The metalloproteinase action was observed in epimastigotes and tripomastigotes forms, demonstrating active and stable presence at the parasite life cycle. The serological reactivity was proven in the groups TcI, TcII and TcIII through ELISA dilutions of 1/100 to 1/12.800. Moreover, the Western Blotting technique was added to SDS-PAGE experiments in infected animals¿ serum after 50 dias and the proteic profile of Y strain was observed in nitrocellulose membrane. The results demonstrated that these eleven strains of T. cruzi have differences between the groups of the parasite. The group TcI showed higher infection rate in cells; TcII, higher value for kinetic growth and TcIII is phylogenetically closer to TcV, which is a hybrid group. The association between parasite and host is able to explain the biological and molecular differences in T. cruzi strains; for this reason, the study of eleven strains isolated from different hosts can add information to the literature and clarify some of the biological aspects of the parasite / Doutorado / Parasitologia / Doutora em Parasitologia
8

Estudo das consequências do bloqueio da produção endógena de ácidos graxos sobre a expressão das integrinas e mmps em modelo murino de melanoma / Effects of the fatty synthesis blockage on the integrin and matrix metalloproteases expression in mouse melanoma

Carvalho, Marco Antonio 12 February 2010 (has links)
Orientador: Edgard Graner / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T08:53:18Z (GMT). No. of bitstreams: 1 Carvalho_MarcoAntonio_D.pdf: 4182553 bytes, checksum: 178a34f020339db79ce9dcd7b7ce717c (MD5) Previous issue date: 2010 / Resumo: O melanoma é, dentre as neoplasias malignas de pele, a de pior prognóstico devido ao seu alto potencial metastático e resistência aos agentes quimioterápicos existentes. A enzima metabólica ácido graxo sintase (FASN, EC2.3.1.85) é a responsável por catalisar a síntese de ácidos graxos saturados de cadeia longa. FASN é um homodímero com massa molecular de 250 kDa responsável pela produção do palmitato endógeno. Em tecidos normais, a atividade metabólica de FASN é mínima, uma vez que a maior parte dos ácidos graxos usados pelas células provém da dieta, com exceção dos tecidos lipogênicos. Por outro lado, tem sido demonstrado que nas células malignas a maior parte dos ácidos graxos provém da biossíntese endógena conseqüente ao aumento da atividade de FASN e que existe uma associação positiva entre a expressão desta enzima metabólica e o comportamento agressivo de tumores malignos, pois sua alta expressão ocorre principalmente em casos com prognóstico ruim. Inibidores específicos da atividade FASN bloqueiam a síntese de DNA e causam apoptose em linhagens celulares derivadas de neoplasias malignas de próstata, mama, cólon, estômago, intestino, endométrio, cavidade bucal, ovário e melanoma. A droga orlistat (Xenical®), aprovada pela FDA e utilizada para o tratamento de obesidade, foi descrita como tendo propriedades anti-neoplásicas em câncer de próstata, mama, cólon, estômago e melanoma, devido a sua capacidade de bloquear especificamente a atividade de FASN. Este trabalho teve como objetivo principal estudar o efeito do tratamento de camundongos C57BL6 com a droga orlistat sobre as atividades de MMPs, expressão de integrinas por células B16F10, adesão destas últimas à macromoléculas da MEC e formação de colônias pulmonares a partir da inoculação na veia caudal de camundongos C57BL6. Através de ensaios zimográficos, não observamos alterações das atividades de MMP-2 e -9 em células B16F10 tratadas com orlistat. No entanto, a inibição de FASN aumentou a adesão das células B16F10 aos componentes de matrix extracelular laminina e fibronectina. Através de ensaios de imunofluorescência observamos uma redução das regiões de adesão focal das integrinas ?v?3 nas células B16F10 tratadas com orlistat. Finalmente, o tratamento com orlistat reduziu em 53,6% o número de colônias metastáticas pulmonares, em comparação aos grupos controle. Em conjunto, os resultados aqui descritos sugerem que esta FASN é um alvo terapêutico em potencial para estes tumores. / Abstract: Malignant melanoma has poor prognosis due to its high metastatic potential and resistance to the existing chemotherapeutic agents. Fatty acid synthase (FASN, EC2.3.1.58) is a metabolic enzyme with molecular mass of 250 kDa responsible for the endogenous biosynthesis of saturated long chain fatty acids. FASN activity is relatively low in most normal human tissues, since most of the fatty acids used by the cells come from the diet, except in liver, adipose tissue, fetal lung and lacting breast. On the other hand, it has been demonstrated that in several cultured malignant cells fatty acids are mostly produced by FASN. A similar phenomenon is also observed in melanoma cells and overexpression of FASN has been associated with a poor prognosis for patients with this malignancy. Specific inhibitors of FASN activity block DNA synthesis and cause apoptosis in prostate, breast, colon, stomach, endometrial, oral cavity, ovary and melanoma cancer cells lines. Orlistat (Xenical®), approved for FDA and used for the treatment of obesity, has antitumor properties in prostate, breast, colon, gastric cancers and melanoma, due to its capacity to block the FASN activity. This work had as main objectives to study the effect of orlistat on the expression and activity of MMPs and expression of integrins in B16F10 cells, as well as on the adhesion of these cells to ECM macromolecules fibronectin and laminin. Moreover, we sought to verify the effect of this drug on the lung colonization by B16F10 innoculated in the tail vein of C57BL6 mice. The treatment with orlistat did not change MMP-2 and -9 gelatinolytic activities in B16F10 cells and enhanced the adhesion of these cells on laminin or fibronectin. Interestingly, treatment of B16F10 cells with orlistat promoted a reduction on the number of integrin ?v?3 focal adhesion plates observed in the immunofluorescence assay. Finally, orlistat promoted an inhibition of 53,6% in the number of lung metastatic foci, in comparison with the control groups, further confirming the anticancer potential of FASN inhibitors. Finally, the results here described suggest that FASN is a therapeutical target in potential for these tumors. / Doutorado / Patologia / Doutor em Estomatopatologia
9

Ação de diferentes cimentos endodônticos sobre a citotoxicidade e a produção de gelatinases em cultura de fibroblastos / Cytotoxic evaluation and up-regulation of gelatinases by root canal sealers in human fibroblast cells

Silva, Emanuel João Nogueira Leal da 17 August 2018 (has links)
Orientador: Alexandre Augusto Zaia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-17T13:58:27Z (GMT). No. of bitstreams: 1 Silva_EmanuelJoaoNogueiraLealda_M.pdf: 1275118 bytes, checksum: 8ef8a33ae74c9038dfc4736d6a1c2cd6 (MD5) Previous issue date: 2011 / Resumo: Os cimentos endodônticos podem entrar em contato com os tecidos periapicais no momento da obturação, gerando uma inflamação transitória. Esta inflamação pode estar associada a uma degradação das proteínas da matriz extracelular pelas metaloproteinases da matriz (MMPs). Dessa forma, o objetivo deste estudo foi avaliar os efeitos de exposição de cimentos endodônticos sobre a atividade gelatinolítica das MMP-2 e -9, produzidas por fibroblastos humanos. Fibroblastos da linhagem MRC5 (3x105 células/poço) foram incubados diretamente ou indiretamente com os cimentos AH Plus, Endomethasone N, Pulp Canal Sealer EWT e Sealapex nos períodos de 1/2h, 1h, 4h e 24h. A citotoxicidade dos cimentos foi determinada pela contagem de células viáveis, utilizando para isso o teste do azul de tripan. Sobrenadantes da cultura de células incubadas com os cimentos endodônticos, nas duas formas testadas, foram coletadas após cada período de exposição, com o objetivo de determinar os níveis de atividade gelatinolítica de MMP-2 e -9, pela técnica da zimografia. Os dados foram submetidos à análise de variância (ANOVA) e avaliados estatisticamente através do teste t (p<0,05). Os resultados mostraram haver uma maior atividade gelatinolítica de MMP-2 após os períodos de 4 e 24 horas, sem haver diferença entre os cimentos testados. Uma maior atividade gelatinolítica pode ser observada nas células que foram expostas ao cimento de forma direta, quando comparadas com aquelas que de receberam o contato indireto com o cimento (p<0,05). Nos períodos de tempo testados nenhuma atividade gelatinolítica pode ser observada no grupo controle, que não recebeu contato com os cimentos. Os resultados de citotoxicidade mostraram que os cimentos testados foram citotóxicos em ambas as formas de contato sendo que o Sealapex apresentou menor citotoxicidade e que o AH Plus foi o cimento mais citotóxico. Pode-se concluir que todos os cimentos endodônticos podem induzir a expressão de MMP-2 em fibroblastos MRC5 e que apesar de o AH Plus possuir a maior citotoxicidade, todos os cimentos testados apresentaram efeitos citotóxicos. / Abstract: Root canal sealers might be into contact with periapical tissues during root canal filling. This inflammation can be associated with extracellular matrix proteins degradation by matrix metalloproteinases (MMPs). The aim of this study was to investigate the effects of root canal sealers on the gelatinolytic acitivity of MMP-2 and -9 produced by human fibroblast cells. Human fibroblast cells MRC5 (3x105 cells/well) were incubated directly or indirectly with AH Plus, Endomethasone N, Pulp Canal Sealer EWT or Sealapex for 1/2h, 1h, 4h or 24h (timepoints). The cytotoxicity of all root canal sealers was determined by counting viable cells using the trypan blue assay. Supernatants of cell cultures incubated with root sealers, directly or indirectly, were collected after each time point to determine the levels of MMP-2 and MMP-9 gelatinolytic activity by gelatin zymography. Data were analyzed using ANOVA and t tests (p<0.05). The results showed that the cells secreted MMP-2 after the periods of 4 and 24 hours. However, there were no statistical differences between the sealers. Secretion of gelatinases was found to be elevated by the sealers in direct contact with the cell monolayer, when compared to the indirect contact (p<0.05). In the timepoints tested no MMP activity could be detected in the control group without the sealers. The cytotoxicity results showed that all the sealers were cytotoxic in both contact forms. These results indicated that Sealapex had a lower cytotoxicity while AH Plus was the most citotoxic endodontic sealer. In conclusion all root canal sealers can induce the expression of MMP-2 in MRC5 fibroblast cells. AH Plus presented the highest cytotoxicity among the tested sealers, but all tested sealers presents citotoxic effects. / Mestrado / Endodontia / Mestre em Clínica Odontológica
10

Avaliação de metaloproteinases e de marcadores inflamatorios em pacientes com sindrome metabolica / Assesment of metaloproteinases and pro-inflammatory markers in patients with metabolic syndrome

Gonçalves, Flávia Magazoni, 1983- 14 August 2018 (has links)
Orientador: Jose Eduardo Tanus dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T03:26:17Z (GMT). No. of bitstreams: 1 Goncalves_FlaviaMagazoni_M.pdf: 1731236 bytes, checksum: 1cf31c8af3a0b8e13751175c3be1b4fe (MD5) Previous issue date: 2009 / Resumo: A síndrome metabólica (MetS) é caracterizada por conjunto de fatores de risco para doenças cardiovasculares e diabetes. As metaloproteinases (MMPs) são enzimas envolvidas na manutenção da homeostase da matriz extracelular e um desequilíbrio entre suas concentrações e as de seus inibidores endógenos (TIMPs) pode ter um papel importante nas modificações cardiovasculares associadas com a MetS. Além disso, um estado inflamatório crônico tem sido descrito em pacientes com MetS e podem levar ao desenvolvimento de aterosclerose. A hipótese deste estudo é que aumento nas concentrações de alguns marcadores pró-inflamatórios e um desequilíbrio entre as concentrações de metaloproteinases de matriz extracelular (MMPs) e seus inibidores endógenos (TIMPs) possam estar envolvidos na fisiopatologia da MetS. Para abordar esta questão, foram estudados 25 indivíduos saudáveis (controles) e 25 pacientes com MetS. As concentrações plasmáticas de pró-MMP-2 e de pró-MMP-9 foram determinadas por zimografia. A concentração plasmática de MMP-8, MMP-3, TIMP-1, TIMP-2, proteína quimioatraente de monócitos-1 (MCP-1), interleucina-6 (IL-6), molécula de adesão intracelular-1 (sICAM-1) e sP-selectina foram medidas por kits de ELISA. Os resultados revelaram um aumento nas concentrações de sP-selectina, sICAM-1, MCP-1, IL-6, pró-MMP-9, MMP-8 e TIMP-1 em pacientes com MetS comparados com controles saudáveis. Além disso, nenhuma diferença nos níveis de pró-MMP-2, MMP- 3 e TIMP-2 foi encontrada. Nossos resultados sugerem que as MMPs podem ter um papel no aumento do risco cardiovascular em pacientes com MetS e que intervenções farmacológicas no alvo das MMPs, especialmente a MMP-9 e a MMP-8 merecem maior atenção em pacientes com MetS / Abstract: The metabolic syndrome (MetS) denotes a clustering of cardiovascular and diabetes risk factors. The metalloproteinase (MMPs) are enzymes involved in maintaining the homeostasis of the extracellular matrix and an imbalance between their concentrations and their endogenous inhibitors (TIMPs) may play important role in the cardiovascular modifications associated with MetS. In addition, a chronic inflammatory state has been described in patients with MetS, thus leading to the development of atherosclerosis. We hypothesized that increased concentrations of pro-inflammatory mediators and imbalanced concentrations of matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs) may reflect the pathophysiology of MetS. To address this issue, we studied 25 healthy subjects and 25 MetS patients. The plasma levels of pro-MMP-2 and pro-MMP-9 were determined by gelatin zymography. The plasma concentrations of MMP-8, MMP-3, TIMP-1, TIMP-2, monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), intercellular adhesion molecule (sICAM-1), and sP-selectin were measured by ELISA kits. The results revealed an increase in sP-selectin, sICAM-1, MCP-1, IL-6, pro-MMP-9, MMP-8, and TIMP-1 in MetS patients compared with healthy controls. In addition, no differences in pro-MMP-2, MMP-3, and TIMP-2 levels were found. These findings suggest that MMPs may have a role in the increased cardiovascular risk of MetS patients and pharmacological interventions targeting MMPs, especially MMP-9 and MMP-8 deserve further investigation in MetS patients / Mestrado / Mestre em Farmacologia

Page generated in 0.1046 seconds