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With approximately 8.5 million unwanted cats euthanized in the U.S. annually, convenient, cost effective methods of sterilization are greatly needed. Current spay/neuter techniques, such as surgery and hormonal intervention, are not satisfying this need due to their high cost, significant expertise required, and the need for feral cats to be collected and brought into clinics for treatment. The aim of this research is to develop a safe contraceptive vaccine that could be delivered to the feral cat population in bait without compromising non-feline species. Feline Herpes Virus (FHV) is a feline specific virus. The USDA has approved the immunization of cats with an attenuated, non-pathogenic strain of FHV expressing foreign antigens. In our research, we have partially replaced Glycoprotein I of FHV to express a fusion protein of Flagellin (FliC), Enhanced Green Fluorescent Protein (EGFP), and Gonadotropin Releasing Hormone (GnRH). FliC has been shown to stimulate a heightened antibody response when antigens are expressed as fusion proteins with it. GnRH, a major reproductive hormone responsible for the development of testes and ovaries in felines, is the target of our vaccine vector. Expression of EGFP will allow tracking of the viral vector. The expression of the fusion protein (FliC-EGFP-GnRH) is expected to stimulate an antibody and cell mediated immune response directed towards feline GnRH, which will provide an immunocontraceptive effect specific to cats. / Master of Science

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal. / Il est maintenant bien établi que les GHRPs constituent une classe de peptides synthétiques stimulant la sécrétion de l'hormone de croissance par interaction avec leur récepteur spécifique au niveau hypophysaire. Ce récepteur constitué de 364 acides aminés appartient à la famille des récepteurs à sept passages transmembranaires couplé aux protéines G. Il est exprimé non seulement au niveau de l'hypophyse mais également au niveau de l'hypothalamus, des noyaux arqués et paraventriculaires. Récemment, il a été découvert par étude de photomarquage covalent que l'hexarelin, un hexapeptide de la famille des GHRPs se lie de façon spécifique à une glycoprotéine membranaire de poids moléculaire de 84 kDa exprimée dans les membranes de coeur de rat. La liaison de l'hexarelin à ce récepteur au niveau cardiaque induit une forte vasoconstriction coronarienne de façon dose­dépendante dans le modèle de coeur de rat perfusé. Les buts de la présente étude sont premièrement de déterminer si la liaison est spécifique seulement à l'hexarelin ou à d'autres analogues peptidiques de la famille des GHRPs, notamment le dérivé EP 70905. Dans un deuxième temps nous déterminerons si les analogues se liant au récepteur cardiaque des GHRPs exercent un effet vasoconstricteur sur les coronaires utilisant le modèle de cœur de rat perfusé. Troisièmement nous caractériserons les voies de signalisation impliquées dans la vasoconstriction induite par les GHRPs. Les études de compétition entre le radioligand photoactivable [125] I-Tyr-Ala-Bpa­hexarelin et le EP 70905 effectuées sur les membranes de cœur de rat démontrent une affinité de liaison comparable du EP 70905 et de l'hexarelin au récepteur cardiaque des GHRPs. Cependant, le EP 70905 induit une augmentation de la pression coronarienne significativement plus élevée que celle induite par l'hexarelin. Les études des voies de signalisation démontrent que les tyrosine kinases ne semblent pas être impliquées dans la vasoconstriction induite par le EP 70905, puisque la perfusion simultanée avec la génistéine n'affecte pas la vasoconstriction induite par ce peptide. Le rôle de l'endothéline endogène dont la libération est stimulée par le EP 70905 semble être mineur dans la vasoconstriction observée considérant les taux femtomolaires d'endothéline libérés dans le perfusat. De plus, la perfusion simultanée d'un antagoniste des récepteurs d'endothéline, le LU 302872 affecte que faiblement la vasoconstriction induite par le EP 70905. Par contre, la vasoconstriction coronarienne induite par le EP 70905 est inhibée de façon majeure suite à la perfusion de la nifédipine, un bloqueur des canaux calciques de type L. La perfusion simultanée d'un inhibiteur de la protéine kinase C, la chélérythrine affecte de façon significative la vasoconstriction induite par le EP 70905.

Le CD36 est un récepteur de type éboueur de classe B exprimé à la surface de nombreux types cellulaires dont les macrophages, les cellules endothéliales de la microvasculature et les plaquettes. Ce récepteur multiligand est impliqué dans plusieurs processus pathologiques notamment l’athérosclérose, l’angiogénèse et la malaria via la liaison spécifique de ligands comme les lipoprotéines oxydées de basse densité, la thrombospondine-1 et la protéine PfEMP-1, respectivement. Les peptides de la relâche de l’hormone de croissance (GHRP) ont été identifiés comme les premiers ligands synthétiques du CD36. Afin de développer de nouveaux ligands synthétiques du CD36, l’établissement d’une méthode de criblage est essentiel pour découvrir des composés avec une liaison de haute affinité pour ce récepteur. Pour y parvenir, nous avons surexprimé le domaine extracellulaire du CD36 humain dans les cellules d’insectes Sf9. La protéine soluble purifiée par chromatographie d’affinité fut immobilisée à la surface d’une plaque de résonance de plasmons de surface (SPR) pour les études de liaison. La méthodologie développée a permis de caractériser les ligands du CD36 en déterminant leurs constantes de dissociation (KD), et d’établir une relation structure-activité des ligands de la famille des azapeptides, des composés dérivés du GHRP-6. Afin de valider la méthode par spectroscopie SPR, une corrélation a été établie entre les valeurs de KD obtenues en SPR et les valeurs d’CI50 de courbes d’inhibition de la phosphorylation des MAP kinases JNK1/2 induite par un phospholipide oxydé, le POVPC, en présence de concentrations croissantes de ligands du CD36 dans les macrophages RAW 264.7. / CD36 is a class B scavenger receptor expressed at the cell surface of macrophages, endothelial cells and platelets, among others. This multiligand receptor is implicated in various diseases such as atherosclerosis, angiogenesis and malaria through the specific binding of ligands, such as oxidized low-density lipoproteins, thrombospondin-1 and the PfEMP-1 protein, respectively. Growth hormone-releasing peptides (GHRP) were identified as the first CD36 synthetic ligands. In order to identify new CD36 synthetic ligands, the development of a high-throughput method is essential to unveil compounds of high binding affinity. We have expressed a recombinant CD36 ectodomain protein in Sf9 insect cells. The soluble and affinity purified protein was immobilized on a surface plasmon resonance (SPR) sensor for binding studies. Synthetic ligands were analyzed by SPR spectroscopy for determination of their respective dissociation constant (KD). A structure-activity relationship of CD36 ligands was established. To validate the SPR binding signal, a good correlation was observed between KD and the IC50 values obtained from the inhibition curves of the MAPK kinase JNK1/2 phosphorylation induced by an oxidized phospholipid, the POVPC, in the presence of increasing concentrations of CD36 ligands in RAW 264.7 macrophage cells.

This diploma thesis deals with the analysis of structural and dynamic organization of thyrotropin releasing hormone receptor (TRH-R) and δ-opioid receptor (DOR) within plasma membrane (PM) in relation to the specific sub-compartments of PM denominated as domains or membrane rafts. Modern fluorescence microscopy techniques FLIM, FRAP and RICS were used for this purpose. The experiments were performed on the live cells derived from HEK293 cell line. To reach the main goal of this work, the integrity of PM structure was altered by depletion of cholesterol which was performed by incubation of cells with β cyclodextrin. Results clearly support our previously suggested idea that the vast majority of TRH-R is localized in non-raft regions of plasma membrane. This work also compared different modes of performance of FRAP and results obtained by FRAP and RICS because these methods are to some extent analogous. This is one of the first works that used the RICS approach to characterize the G protein-coupled receptors. In the second part of this work, the setup of transient transfection of the HEK293 cells with DOR-ECFP and DOR EYFP constructs was established. Simultaneously, the functionality of these constructs, i.e. the ability of DOR to activate the cognate G protein was determined. Powered by TCPDF (www.tcpdf.org)

En odontologie, la perte d'éléments naturels est palliée par l'utilisation de biomatériaux de reconstruction d'origine métallique ou céramique, celle-ci connait actuellement un fort développement avec une propension à supplanter le métal pour n'avoir que du « tout céramique ». Ces matériaux sont, par leur fonction, amenés à séjourner durablement dans le milieu buccal favorisant l'apparition de phénomènes corrosifs. La salive est un électrolyte efficace auquel viennent s'ajouter les variations de pH, de température, le polymétallisme, augmentant la vitesse de corrosion et le relargage des éléments constituants. L'étude porte sur cinq alliages couramment utilisés en odontologie prothétique : un précieux, un semi précieux et trois non précieux, et des céramiques d'infrastructure, visant à remplacer les alliages : zircone, alumine et disilicate de lithium. Tous les échantillons subissent en statique une attaque salivaire, et en dynamique une combinaison d'action salivaire et d'usure grâce à une machine unique, simulant le plus précisément possible les mouvements cuspidiens en présence constante de salive artificielle reproduisant de très près les conditions intra-buccales. L'analyse des échantillons au M.E.B.et les résultats de la spectrométrie montrent au niveau alliage un excellent comportement du Cr Co et du titane. Les céramiques montrent aussi des propriétés remarquables sur le plan biologique infirmant pour certaines les ressentis cliniques. Par contre une usure importante des dents naturelles antagonistes ne leur confère pas une biocompatibilité parfaite / In dentistry, the loss of natural elements is made up for by the use of reconstruction biomaterials of metal or ceramic origin. The use of the latter is now fastly developing and tends to supersede metal, to have only "all ceramic" elements. All these materials will remain in the mouth of the patients for a long time, which creates optimal conditions for the appearance of corrosion phenomena. Saliva is indeed an effective electrolyte. The variations in pH, temperature and polymetalism increase the speed of corrosion and the release of the component elements. The present study concerns five alloys usually used in prosthetic dentistry: one noble, one high noble, three basic alloys and several ceramics of infrastructure to replace alloys: zirconia, alumina and lithium disilicate. All the samples undergo a salivary attack in statics, and a combination of salivary action and wear in dynamics thanks to a unique machine, simulating as exactly as possible the buccal conditions. The analysis of the samples in the S.E.M., as well as the spectrometry results, suggest that the Co-Cr alloy and titanium present an excellent behaviour. Ceramics also show remarkable properties on the biological plan, in spite of certain people's clinical experience. However, an important wear of the opposing natural teeth does not give them a perfect biocompatibility

A doença de Chagas é uma parasitose extremamente negligenciada, cujo agente etiológico é o protozoário Trypanosoma cruzi. Atualmente, 21 países da América Latina são considerados regiões endêmicas, onde 75-90 milhões de pessoas estão expostas à infecção, 6-7 milhões estão infectadas e mais de 41 mil novos casos surgem por ano. Entretanto, apenas os fármacos nifurtimox e benznidazol estão disponíveis no mercado. Estes, além da baixa eficácia na fase crônica da parasitose, apresentam diversos efeitos adversos, sendo que no Brasil apenas o benznidazol é utilizado. Este fato mostra a importância de se ampliar o número de fármacos disponíveis e propor quimioterapia mais eficaz para o tratamento da doença de Chagas. Como forma de contribuir para essa busca, este trabalho objetiva a síntese de compostos híbridos bioisostéricos N-acilidrazônicos e sulfonilidrazônicos, contendo grupo liberador de óxido nítrico, com potencial de interação com cisteíno-proteases parasitárias, tais como a cruzaína. Nestes derivados, os grupos liberadores de óxido nítrico utilizados foram os grupos furoxano (contendo substituinte metílico e fenílico) e éster nitrato. Propôs-se a variação de anéis aromáticos substituídos e não-substituídos, com o intuito de avaliar a possível relação estrutura-atividade (REA) desses análogos. Até o momento, somente os compostos da série N-acilidrazônica tiveram avaliação biológica realizada. Os valores de IC50 dos compostos na forma amastigota do parasita variaram entre >100 a 2,88 µM, sendo este último valor comparável ao fármaco de referência. A atividade inibitória frente à cruzaína foi de 25,2 µM a 2,2 µM. Já a liberação de óxido nítrico foi avaliada pelo método indireto de detecção de nitrato e os valores variaram entre 52,0 µM e 4.232,0 µM. Estes são bem inferiores ao composto padrão, além de não se identificar correlação direta entre a atividade biológica e a liberação de NO. Na sequência, os dois compostos mais ativos (6 e 14) foram submetidos a estudos de permeabilidade e de citotoxicidade. O composto 6 foi considerado o de maior permeabilidade segundo o Sistema de Classificação Biofarmacêutica (SCB) e todos os compostos apresentaram a taxa de fluxo menor que 2, indicando a ausência de mecanismo de efluxo. Na avaliação do potencial citotóxico desses compostos em células humanas, o derivado 6 apresentou índice de seletividade superior ao do benznidazol. Em estudos de modelagem molecular usando análise exploratória de dados (HCA e PCA), propriedades estéricas/geométricas e eletrônicas foram consideradas as mais relevantes para a atividade biológica. Além disso, estudos de docking mostraram que a posição do grupo nitro no anel aromático é importante para a interação com a cruzaína. Ademais o composto 6 não provocou mudanças significativas no ciclo celular e na fragmentação de DNA em células humanas, mostrando-se como líder promissor para futuros estudos in vivo. Atividade tripanomicida, citotoxicidade, potencial de liberação de NO e estudos de permeabilidade dos 23 derivados sulfonilidrazônicos e ésteres nitrato estão sendo avaliados. / Chagas disease is an extremely neglected parasitic disease whose etiologic agent is the protozoan Trypanosoma cruzi. Currently 21 Latin American countries are considered endemic regions, where 75-90 million people are exposed to infection, 6-7 million are infected and more than 41,000 new cases occur annually. However only nifurtimox and benznidazole are available on the market. These drugs, besides low efficacy in the chronic phase of the parasite have numerous adverse effects, and in Brazil only benznidazole is used. This fact shows the importance of increasing the number of drugs available and propose more effective chemotherapy for the Chagas disease treatment. As a contribution to the problem, this study aims the synthesis of biososteric compounds from N-acylhydrazone and sulfonylhydrazone, which have the potential to interact with parasitic cysteine protease, such as cruzain, containing nitric oxide releasing groups, which also has inhibitory activity in this enzyme class. In these derivatives nitric oxide releasing groups used were furoxan (containing methyl and phenyl substituent) and nitrate ester groups. The variation of aromatic rings substituted and unsubstituted was proposed in order to evaluate the possible structure-activity relationship (SAR) of these analogs. Only N-acylhydrazone series had its biological profile evaluated up to now. The IC50 values of the compounds against the amastigote form of the parasite ranged from >100 µM to 2.88 µM, the last value being comparable to that of reference drug. Cruzain inhibitory activity ranged from 25.2 µM to 2.2 µM. The nitric oxide releasing potential was evaluated using the indirect method of detection and nitrate values ranged between 52.0 µM and 4,232.0 µM. These results are below than those of the standard compound, and there is no direct correlation between the biological activity and nitric oxide releasing potential as well. Further, the two most active compounds (6 and 14) were submitted to permeability and cytotoxicity studies. Compound 6 showed the highest permeability value according to Biopharmaceutics Classification System (BCS), and both compounds showed flow rate lower than 2, indicating no efflux mechanism. In the cytotoxicity studies of these compounds in human cells, the derivative 6 showed selectivity index greater than benznidazole. In molecular modeling studies using exploratory data analysis (HCA and PCA) steric/geometric and electronic properties were considered the most relevant for biological activity. In addition, docking studies were performed and showed that the position of the nitro group on the aromatic ring is important for the interaction with cruzain. Compound 6 did not cause significant changes in cell cycle and DNA fragmentation in human cells, showing to be a promising lead compound for future in vivo studies. Trypanocidal activity, cytotoxicity assay, NO releasing potential and permeability studies of the 23 sulfonylhydrazones and nitrate ester derivatives are being evaluated.

A kisspeptina, codificada pelo gene KISS1, é um neuropeptídeo crucial na regulação do início da puberdade. A kisspeptina estimula a secreção hipotalâmica do hormônio liberador de gonadotrofinas (GnRH) após se ligar ao seu receptor GPR54. Mutações inativadoras do GPR54 são atualmente consideradas como uma causa rara de hipogonadismo hipogonadotrófico isolado (HHI) normósmico. Recentemente, uma mutação ativadora no receptor GPR54 foi implicada na patogênese da puberdade precoce dependente de gonadotrofinas (PPDG). Com base nesses achados, levantamos a hipótese de que alterações no gene KISS1 poderiam contribuir para a patogênese de distúrbios puberais centrais. O objetivo do presente estudo foi investigar a presença de variantes no gene KISS1 em pacientes com PPDG e HHI. Sessenta e sete crianças brasileiras com PPDG (63 meninas e 4 meninos) e 61 pacientes com HHI (40 homens e 21 mulheres) foram selecionados, incluindo casos esporádicos e familiares em ambos os grupos. A população controle consistiu de 200 indivíduos com história de desenvolvimento puberal normal. A região promotora e os 3 exons do gene KISS1 foram amplificados e submetidos a sequenciamento automático. Duas novas variantes no gene KISS1, p.P74S e p.H90D, foram identificadas em duas crianças não relacionadas, portadoras de PPDG idiopática. Ambas as variantes estão localizadas na região amino-terminal da kisspeptina-54 e estavam ausentes em 400 alelos controles. A variante p.P74S foi identificada em heterozigose em um menino que desenvolveu puberdade com um ano de idade. Sua mãe e avó materna, que apresentavam história de desenvolvimento puberal normal, eram portadoras da mesma variante em heterozigose, sugerindo penetrância incompleta e/ou herança sexo-dependente. A variante p.H90D foi identificada em homozigose em uma menina com PPDG, que desenvolveu puberdade aos seis anos de idade. Sua mãe, com história de menarca aos dez anos de idade, era portadora da mesma variante em heterozigose. Células transfectadas estavelmente com GPR54 foram estimuladas com concentrações crescentes de kisspeptina-54 (kp-54) humana selvagem ou contendo as mutações (kp-54 H90D e kp-54 P74S) e o acúmulo de fosfato de inositol (IP) foi medido. Nos estudos in vitro, a kp-54 P74S apresentou uma capacidade de ativação do receptor GPR54 semelhante à kp-54 selvagem. A kp-54 p.H90D mostrou uma ativação da sinalização do receptor significativamente mais potente que a kp-54 selvagem, sugerindo que essa é uma mutação ativadora. No grupo de HHI, uma nova variante (c.588-589insT) foi identificada em heterozigose na região 3 não traduzida do gene KISS1 em um paciente do sexo masculino. O papel dessa variante no fenótipo de HHI permanece indeterminado. Em conclusão, duas mutações no gene KiSS1 foram descritas pela primeira vez em associação com PPDG. / Kisspeptin, encoded by the KISS1 gene, is an important regulator of puberty onset. After binding to its receptor GPR54, kisspeptin stimulates gonadotropin-releasing hormone secretion by the hypothalamic neurons. Inactivating GPR54 mutations are a rare cause of normosmic isolated hypogonadotropic hypogonadism (IHH). Recently, a unique GPR54 activating mutation was implicated in the pathogenesis of gonadotropin dependent precocious puberty (GDPP). Based on these observations, we hypothesized that mutations in the KISS1 gene might be associated with central pubertal disorders. The aim of this study was to investigate KISS1 mutations in idiopathic GDPP and normosmic IHH. Sixty-seven Brazilian children (63 girls and 4 boys) with idiopathic GDPP and 61 patients with normosmic IHH (40 men and 21 women) were selected. Familial and sporadic cases were included in both groups. The control population consisted of 200 individuals who had normal timing of puberty. The promoter region and the 3 exons of the KISS1 gene were amplified and automatically sequenced. Two novel KISS1 missense mutations, p.P74S and p.H90D, were identified in two unrelated children with idiopathic GDPP. Both mutations were absent in 400 control alleles and are located in the amino-terminal region of kisspeptin-54. The p.P74S mutation was identified in the heterozygous state in a boy who developed puberty at 1 yr of age. His mother and maternal grandmother, who had normal pubertal development, were also heterozygous for the p.P74S mutation, suggesting incomplete penetrance and/or sex-dependent inheritance. The p.H90D mutation was identified in the homozygous state in a girl with GDPP, who developed puberty at 6 yr of age. Her mother, who had menarche at 10 yr of age, carried the p.H90D mutation in the heterozygous state. CHO cells stably transfected with GPR54 were stimulated with different concentrations of synthetic human wild type or mutant kisspeptin-54 (KP54) and inositol phosphate (IP) accumulation was measured. In vitro studies revealed that the capacity of the p.P74S mutant KP54 to stimulate IP production was similar to the wild type. The p.H90D kisspeptin-54 showed a significantly more potent activation of GPR54 signaling in comparison to the wild type in vitro, suggesting a gain-of-function mutation. In the IHH group, a heterozygous variant in the 3 UTR of the KISS1 gene (c.588-589insT) was identified. The role of this variant in the IHH phenotype remains to be determined. In conclusion, two KiSS1 mutations were described for the first time in association with GDPP.

Introdução: A ativação do eixo hormônio liberador de corticotropina (CRH) e da pró-opiomelanocortina (POMC) leva a produção de vários derivados bioativos que incluem o hormônio adrenocorticotrófico (ACTH) e o hormônio estimulador de melanócito alfa (alfa-MSH). Estudos avaliando a participação desse eixo no lúpus eritematoso sistêmico (LES) são escassos, particularmente no envolvimento cutâneo da doença. Objetivo: Avaliar a participação do CRH e das melanocortinas (MCs) na fisiopatologia do lúpus eritematoso sistêmico com envolvimento cutâneo. Métodos: Dezessete pacientes com LES com envolvimento cutâneo foram avaliados clinicamente e biópsias da pele afetada e não afetada e do sangue periférico foram obtidas. Dezessete indivíduos saudáveis foram pareados por idade e gênero. Os fragmentos de pele foram submetidos à análise imuno-histoquímica para avaliação da expressão de CRH, ACTH, alfaMSH, e receptor de melanocortina tipo 1 (MC-1R). Os níveis séricos de alfa-MSH, IL-1, IL-1ra, IL-6, IL-10, IL-12p70, IL-17, TNF-alfa, e IFN-y foram determinados pelo método Multiplex. Resultados: A pele afetada de pacientes com LES apresentaram maior expressão CRH na derme profunda quando comparada à pele não afetada dos mesmos doentes e a pele saudável dos controles (p = 0,024). Níveis séricos de alfa-MSH foram similares entre LES e controles. Dentre as citocinas avaliadas, IFN-y, TNF-alfa e IL-6 foram mais elevadas nos pacientes com LES em relação aos controles (p = 0,041, p = 0,001 e p = 0,049, respectivamente). Embora não significativamente, os níveis de IL-17 também foram mais altos nos pacientes (p = 0,099). A expressão tecidual de ACTH, cortisol, alfa-MSH e seu receptor MC-1R foram semelhantes entre os pacientes e controles. Conclusões: Nossos resultados mostram, pela primeira vez a participação do eixo CRH-POMC na patogênese das lesões cutâneas do LES / Introduction: Corticotropin-releasing hormone (CRH) and pro-opiomelanocortin (POMC) axis activation leads to the production of several bioactive hormones including adrenocorticotrophic hormone (ACTH) and the neuropeptide alfa-melanocyte stimulating hormone (alfa-MSH). There are scarce data regarding their role in systemic lupus erythematosus (SLE) particularly in cutaneous involvement of this disease. Objective: To evaluate the role of CRH and melanocortins (MCs) in the pathophysiology of systemic lupus erythematosus with skin involvement. Methods: Seventeen patients with SLE with skin involvement were evaluated clinically and biopsies of affected and unaffected skin and peripheral blood were obtained. Seventeen healthy subjects were matched for age and gender. The skin fragments were subjected to immunohistochemical analysis for the expression of CRH, ACTH, alfa-MSH and melanocortin receptor type 1 (MC-1R). Serum levels of alfa-MSH, IL-1, IL-1ra, IL-6, IL-10, IL-12p70, IL-17, TNF-alfa and IFN-y were determined by multiplex. Results: The affected skin of SLE patients exhibited greater CRH expression in the deep dermis compared to unaffected skin of the same patients and the control\'s healthy skin (p = 0.024). alfa-MSH were similar between SLE and controls. Among the evaluated cytokines, IFN-y, TNF-alfa and IL-6 were significantly higher in SLE patients compared to controls (p = 0.041, p = 0.001 and p = 0.049, respectively). Although not significant, levels of IL-17 were also higher in patients (p = 0.099). Tissue expression of ACTH, cortisol, alfa-MSH and its receptor MC-1R were similar between patients and controls. Conclusions: Our results show for the first time the involvement of CRH-POMC axis in the pathogenesis of SLE cutaneous lesions through interactions between the brain-skin axis