Made available in DSpace on 2016-01-07T13:36:23Z (GMT). No. of bitstreams: 2 bianca_vitorio_ioc_mest_2014.pdf: 8997482 bytes, checksum: 58bdb04feb407967d076809db7227935 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2015-04-14 / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Rio de Janeiro, RJ, Brasil / As diversas espécies de Leishmania são parasitas de considerável importância médica e econômica. As drogas atualmente utilizadas no tratamento da leishmaniose apresentam efeitos adversos, alta toxicidade, elevado custo e surgimento de cepas resistentes. Nesse contexto, inibidores proteolíticos é uma alternativa para o tratamento desta doença. Este estudo está focado nas calpaínas, que compreendem uma família de cisteína peptidases neutras dependentes de cálcio, envolvidas numa ampla variedade de funções fisiológicas. As calpaínas estão envolvidas em importantes doenças humanas, portanto inibidores de calpaínas já vêm sendo desenvolvidos e testados para o tratamento dessas doenças, alguns encontra-se em estágios avançados de triagem clínica. Dessa forma, o presente trabalho avalia a expressão e identificação de homólogos das calpaínas em Leishmania braziliensis e o efeito do inibidor de calpaínas MDL28170 em ensaios in vitro. Através da busca por sequências no GenBank, alinhamentos múltiplos, filogenia e análise de domínios conservados nas sequências obtidas, selecionamos como alvo inicial sequências de calpaínas que possuíam o maior número de domínios conservados. A análise da expressão gênica relativa indica que 13 das 20 calpaínas estudadas apresentam níveis constitutivos de mRNA nas formas procíclica e metacíclica de L. braziliensis. A expressão de cinco alvos é maior na forma procíclica, e a de um alvo é maior na forma metacíclica e há expressão estágio específica de apenas um alvo na forma procíclica. A partir de análises in silico, das sequências proteicas dessas calpaínas, selecionamos uma região consenso e um peptídeo correspondente a essa região foi sintetizado e empregado na imunização de coelhos A reatividade do anticorpo gerado (Anti-TryTrip CALPAIN) foi avaliada por Western blotting, citometria de fluxo e imunocitoquímica. Em ensaios de Western blotting,verificamos que o anticorpo foi capaz de reagir contra uma proteína de 50 kDa. Já na imunolocalização foi possível observar calpaínas dispersas no citoplasma, membrana e núcleo. Além disso, através de citometria de fluxo, as moléculas homólogas às calpaínas foram identificadas em maior abundância no interior das células. Nos ensaios de inibição com o MDL28170, inibidor de calpaínas, foi possível observar a redução da proliferação nas formas promastigotas recém isoladas e múltiplas passagens de forma dose-dependente nas diferentes concentrações do inibidor ao longo de quatro dias. O efeito reversíveldo inibidor também foi avaliado nas formas promastigotas, com taxas menores comparado com o controle. O efeito do inibidor, também foi capaz de diminuir de maneira dose-dependente o índice de associação e aumentou o percentual de células com parasitos aderidos durante o processo de interação com macrófagos peritoneais. O parasito aumentou a expressão de uma peptidse clássica (gp63) quando tratado com o MDL28170, já a expressão de calpaínas e cpb não foi alterada pelo estresse induzido pelo composto. Estes dados sugerem mais estudos para melhor caracterizar as calpaínas em L. braziliensis e sugerem uma maior avaliação para uma possível associação de moléculas similares as calpaínas com a virulência ou não do parasito. Assim este trabalho acrescenta novas possibilidades para a utilização de inibidores de calpaínas como um potencial alvo de desenvolvimento para o tratamento da leishmaniose / The various species of Leishmania are parasites of considerable medical and economic importance. The drugs used in the treatment of leishmaniasis have adverse effects, high toxicity, high cost and emergence of resistant strains. In this context, proteolytic inhibitors could be an alternative for the treatment of this disease. This study is focused on calpains, which comprise a family of neutral cysteine peptidases, which are strictly dependent of calcium, and are there of known as Calcium Dependent Peptidases.These enzymes play a variety of physiological functions, and are involved in human diseases, therefore calpains inhibitors are under trial to treat these diseases. Thus, this study aimed to assess calpain expression levels in Leishmania braziliensis, as well as the effect of the calpain inhibitor MDL28170 in vitro. Through the searching for sequencesin GenBank, multiple alignments, and phylogenetic analysis of the obtained sequences conserved domains, selected as an initial target sequences of calpain which possessed the greatest number of conserved domains. In this sense, we assessed the expression levels of mRNA from a group of twenty sequences containing archetypal calpain domain. The analysis indicated that 13 out of the 20 studied calpains have constitutive levels of mRNA between the procyclic and metacyclic forms of L. braziliensis, while five calpains presented higher expression levels at the procyclic stage, and only one sequence is augmented at the metacyclic stage. One calpain molecule was found to be procyclic-specific. After that, we selected a consensus region and a peptide was synthesized and used to immunize rabbits. The reactivity of the antibody (anti-calpainTryTrip) was evaluated by Western blotting, flow cytometry and immunocytochemistry. In Western blotting assays, we found that the anti-calpain TriTryp antibody was able to recognize a 50 kDa protein. The immunolocalization assays revealed calpain molecules present at the membrane, nucleus and dispersed throughout the cytoplasm. Also, by flow cytometry, molecules homologous to calpains have been identified in abundance within cells. In inhibition assays employing MDL28170, a potent and specific calpain inhibitor, it was possible to observe a dose-dependent reduction in the proliferation rate, either in freshly isolated promastigotes or multiple passages parasites. MDL28170 presents a reversible inhibitory effect. The inhibitor was also able to decrease in a dose-dependent manner the association index and the percentage of host cells with attached parasites during the process of interaction with peritoneal macrophages. Finally, MDL28170 enhanced the expression of gp63 molecules, while cpb and calpains expression were not affect. Further studies to better characterize the calpain in L. braziliensis should be performed, aiming to add new possibilities for the exploitation of calpain inhibitors as a potential for the treatment of leishmaniasis. / The various species of Leishmania are parasites of considerable medical and economic importance. The drugs used in the treatment of leishmaniasis have adverse effects, high toxicity, high cost and emergence of resistant strains. In this context, proteolytic inhibitors could be an alternative for the treatment of this disease. This study is focused on calpains, which comprise a family of neutral cysteine peptidases, which are strictly dependent of calcium, and are there of known as Calcium Dependent Peptidases.These enzymes play a variety of physiological functions, and are involved in human diseases, therefore calpains inhibitors are under trial to treat these diseases. Thus, this study aimed to assess calpain expression levels in Leishmania braziliensis, as well as the effect of the calpain inhibitor MDL28170 in vitro. Through the searching for sequencesin GenBank, multiple alignments, and phylogenetic analysis of the obtained sequences conserved domains, selected as an initial target sequences of calpain which possessed the greatest number of conserved domains. In this sense, we assessed the expression levels of mRNA from a group of twenty sequences containing archetypal calpain domain. The analysis indicated that 13 out of the 20 studied calpains have constitutive levels of mRNA between the procyclic and metacyclic forms of L. braziliensis, while five calpains presented higher expression levels at the procyclic stage, and only one sequence is augmented at the metacyclic stage. One calpain molecule was found to be procyclic-specific. After that, we selected a consensus region and a peptide was synthesized and used to immunize rabbits. The reactivity of the antibody (anti-calpainTryTrip) was evaluated by Western blotting, flow cytometry and immunocytochemistry. In Western blotting assays, we found that the anti-calpain TriTryp antibody was able to recognize a 50 kDa protein. The immunolocalization assays revealed calpain molecules present at the membrane, nucleus and dispersed throughout the cytoplasm. Also, by flow cytometry, molecules homologous to calpains have been identified in abundance within cells. In inhibition assays employing MDL28170, a potent and specific calpain inhibitor, it was possible to observe a dose-dependent reduction in the proliferation rate, either in freshly isolated promastigotes or multiple passages parasites. MDL28170 presents a reversible inhibitory effect. The inhibitor was also able to decrease in a dose-dependent manner the association index and the percentage of host cells with attached parasites during the process of interaction with peritoneal macrophages. Finally, MDL28170 enhanced the expression of gp63 molecules, while cpb and calpains expression were not affect. Further studies to better characterize the calpain in L. braziliensis should be performed, aiming to add new possibilities for the exploitation of calpain inhibitors as a potential for the treatment of leishmaniasis.

La spasticité et la douleur neuropathique sont deux symptômes apparaissant fréquemment après une lésion médullaire. La spasticité est définie comme une augmentation du tonus musculaire qui provoque des contractures, tandis que la douleur neuropathique se caractérise par des sensations douloureuses survenant suite à une lésion du système nerveux.Ces deux symptômes résultent en partie d’une désinhibition des réseaux neuronaux sous-lésionnels lié à une diminution de l’expression du cotransporteur potassium-chlorure type 2 (KCC2). Pour être efficace,l’inhibition nécessite l’action de cette protéine qui extrait les ions chlorure des neurones.L’objectif de la présente thèse est donc d’identifier des médicaments capables d’activer KCC2 afin de restaurer l’inhibition dans le but de traiter la spasticité et la douleur neuropathique.Dans un premier temps, nos résultats ont montré que l’activation de récepteurs sérotoninergiques 5-HT2A avec le TCB-2 rétablit l’expression de KCC2 dans la corne dorsale après une lésion médullaire ou névrectomie. Or le TCB-2 réduit seulement la douleur neuropathique après la lésion spinale.Par la suite, nous avons identifié la prochlorperazine comme une molécule augmentant l’activité de KCC2. Si la prochlorperazine est efficace contre la spasticité, elle a néanmoins un effet plus modeste envers l’allodynie mécanique suite à une lésion médullaire.Enfin, nous avons démontré que la diminution de KCC2,ainsi que l’hyperexcitabilité des motoneurones suite à la lésion, dépendent de l’activation des calpaïnes.Cette thèse valide KCC2 comme une cible thérapeutique dans le traitement de la spasticité et la douleur neuropathique suite à une lésion médullaire. / Spasticity and neuropathic pain are two symptoms that arise frequently after a spinal cord injury. Spasticity is defined as an increase of the muscle tone contributing to cramps, whereas neuropathic pain consists of painful responses caused by a damaged nervous system. Both symptoms arise, in part, due to a loss of inhibition in the sublesional neural networks, linked to a downregulation of the expression of potassium-chloride cotransporter type 2 (KCC2). For inhibition to be efficient, the action of this protein, which extrudes chloride ions from neurons, is needed.The objective of this thesis is, therefore, to identify drugs capable of activating KCC2 to recover inhibition with the objective of treating spasticity and neuropathic pain.First, our results have proven that the activation of serotonin receptors 5-HT2A with TCB-2 restores KCC2 expression in the dorsal horn after a spinal cord or peripheral nerve injury. However, TCB-2 reduces neuropathic pain after a spinal cord injury exclusively.In the next stage of the work, we have identified prochlorperazine as an enhancer of KCC2 activity. Prochlorperazine is efficient against spasticity, although it only showed a modest reduction of mechanical hyperalgesia in animals with a spinal cord injury.Lastly, we have proven that KCC2 downregulation and motoneuron hyperexcitability after a spinal cord injury depend on the overactivation of calpains.This thesis validates KCC2 as a druggable target to treat spasticity and neuropathic pain after spinal cord injury.

Submitted by Tatiana Silva (tsilva@icict.fiocruz.br) on 2013-02-15T18:25:22Z No. of bitstreams: 1 vitor_e_vidal_ioc_bcm_0021_2010.pdf: 5115263 bytes, checksum: fa627a814efc2aa5bda7207fe780c399 (MD5) / Made available in DSpace on 2013-02-15T18:25:22Z (GMT). No. of bitstreams: 1 vitor_e_vidal_ioc_bcm_0021_2010.pdf: 5115263 bytes, checksum: fa627a814efc2aa5bda7207fe780c399 (MD5) Previous issue date: 2010 / Fundação Oswaldo Cruz.Instituto Oswaldo Cruz. Rio de janeiro, RJ, Brasil / As calpaínas constituem uma família de cisteína-peptidases neutras dependentes de cálcio presentes numa ampla variedade de organismos. Em virtude da relevância fisiológica dessa proteases, inibidores de calpaínas já vêm sendo desenvolvidos para o tratamento de doenças humanas e microbianas. Estudos recentes vêm relatando a presença de diversas proteínas relacionadas às calpaínas em tripanossomatídeos, mas pouco se sabe a respeito das funções específicas dessas proteínas nesses micro-organismos. Nesse contexto, uma vez que os fármacos atualmente disponíveis para o tratamento da doença de Chagas apresentam sérios efeitos colaterais e podem ser ineficazes, inibidores proteolíticos poderiam ser uma alternativa no tratamento desta doença. Portanto, o presente trabalho investiga a presença de moléculas similares às calpaínas no Trypanosoma cruzi e o efeito inibidor do inibidor III de calpaínas (MDL28170) sobre a proliferação, viabilidade, diferenciação, ultraestrutura e interação das diferentes formas do parasito com células hospedeiras em ensaios in vitro. Nossos resultados revelam a reatividade cruzada de anticorpos produzidos contra calpaínas já bem caracterizadas de Drosophila melanogaster, Homarus americanus e. Trypanosoma brucei contra moléculas de superfície do T. cruzi, conforme demonstrado por imunofluorescência e citometria de fluxo. Em ensaios de Western Blotting foi possível observar que o anticorpo anti-DM-calpaína foi capaz de reagir contra uma proteína de 80 kDa. Pesquisas realizadas no GenBank demonstraram a presença de 4 seqüências nomólogas à calpaína de D. melanogaster no genoma do T. cruzi. Essas 4 seqüências foram identificadas como cisteína-paptidases de massa molecular predita em torno de 80kDa. Nos ensaios de inibição com o MDL28170 foi possível observar a redução da proliferação das formas epimastigotas ao longo de 5 dias de cultura; e a redução significativa da viabilidade das formas tripomastigotas sanguíneas dos parasitos tratados com 25 µM do composto. O inibidor, adicionado nas concentrações de 6,25 à 25 µM, também foi capaz de diminuir de forma dose- e tempo-dependente o número de macrófagos parasitados e o número de parasitas interiorizados nos ensaios de interação com macrófagos peritoneais murinos. O MDL28170 em concentração a partir de 12,5 µM teve ainda um efeito inibitório significativo sobre a adesão de formas epimastigotas ao epitélio intestinal de Rhodnius prolixus; assim como os anticorpos anti-calpaínas foram capazes de inibir significativamente a interação com o inseto vetor. Por fim, foi possível observar uma redução significativa no processo de diferenciação por metaciclogênese em meio TAU e alterações ultraestruturais em reservossomos, Golgi e membrana plasmática quando formas epimastigotas do T. cruzi foram tratadas com MDL28170.. Embora mais estudos sejam necessários para melhor caracterizar moléculas similares às calpaínas no T. cruzi, o nosso trabalho acrescenta novos conhecimentos sobre as possíveis funções dessas moléculas e sobre a possibilidade de utilização de inibidores de calpaínas como uma alternativa promissora para o desenvolvimento de compostos mais potentes e seletivos para o tratamento da doença de Chagas. / The calpains are a family of cysteine ​​peptidases neutral calcium dependent present in a wide variety of organisms. Due to the physiological relevance of such proteases, calpain inhibitors have already been developed for the treatment of human diseases and microbial. Recent studies have reported the presence of several proteins related to calpain in trypanosomatids, but little is known about the specific functions of these proteins in these micro-organisms. In this context, since the drugs currently available for the treatment of Chagas' disease have serious side effects and can be ineffective, proteolytic inhibitors could be an alternative in treatment of this disease. Therefore, the present study investigates the presence of molecules similar to calpain in Trypanosoma cruzi and the inhibitory effect of calpain inhibitor III (MDL28170) on proliferation, viability, differentiation, ultrastructure and interaction of the different forms of the parasite with host cells in vitro tests . Our results reveal the cross-reactivity of antibodies produced against calpains already well-characterized Drosophila melanogaster, and Homarus americanus. Trypanosoma brucei against surface molecules of T. cruzi, as demonstrated by immunofluorescence and flow cytometry. In assays Western Blotting was observed that the anti-DM-calpain was able to react against a protein of 80 kDa. Surveys conducted in GenBank showed the presence of 4 nomólogas the calpain sequences of D. melanogaster genome of T. cruzi. These four sequences were identified as cysteine ​​paptidases predicted molecular mass of around 80 kDa. In inhibition assays with MDL28170 was possible to observe a reduction in the proliferation of epimastigotes over 5 days of culture, a significant reduction in the viability of blood trypomastigotes of parasites treated with 25 mM of the compound. The inhibitor added at concentrations of 6.25 to 25 mM, was also able to decrease in a dose-and time-dependent number of infected macrophages and the number of parasites internalized interaction assays with murine peritoneal macrophages. The MDL28170 in concentration from 12.5 mM still had a significant inhibitory effect on the adhesion of epimastigotes to the intestinal epithelium of Rhodnius prolixus, as well as anti-calpain were able to significantly inhibit the interaction with the insect vector. Finally, we observed a significant reduction in the differentiation process by metacyclogenesis amid TAU and ultrastructural changes in reservossomos, Golgi and the plasma membrane when epimastigotes of T. cruzi were treated with MDL28170 .. Although more studies are needed to better characterize molecules similar to calpains in T. cruzi, our work adds new insights into the possible roles of these molecules and the possibility of using inhibitors of calpain as a promising alternative for the development of more potent and selective compounds for the treatment of Chagas' disease.