Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-23T14:56:57Z No. of bitstreams: 1 DIS_FERNANDA_TEIXEIRA_SUBTIL_COMPLETO.pdf: 1495988 bytes, checksum: 70f1cb1dccabfa7c302effb51db76e03 (MD5) / Made available in DSpace on 2017-06-23T14:56:57Z (GMT). No. of bitstreams: 1 DIS_FERNANDA_TEIXEIRA_SUBTIL_COMPLETO.pdf: 1495988 bytes, checksum: 70f1cb1dccabfa7c302effb51db76e03 (MD5) Previous issue date: 2017-03-03 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The high incidence of tuberculosis is a great concern worldwide. Different strategies are being developed by the World Health Organization to fight tuberculosis. Amongst the three pillars that are part of the End TB Strategy, we can highlight the intensive research and innovation pillar. In this extent, the development of new drugs for tuberculosis treatment is a field that is gaining importance. The 2(quinolin-4-yloxy) acetamides are molecules that showed promising bactericidal effects in Mycobacterium tuberculosis, which motivated us to continue studying to improve their mycobactericidal activity and also perform their chemical and biological characterization. In order to continue the 2(quinolin-4-yloxy) acetamides derivatives development, the target identification of these molecules is a keystone and is also the focus of this study. Initially, it was hypothesized that DNA gyrase was their molecular target due to the great chemical similarities between the 2(quinolin-4-yloxy) acetamides and the fluoroquinolones. Despite our results that the 2(quinolin-4-yloxy) acetamides have diminished effects in ofloxacin resistant clinical isolates, the results obtained with the gyrA point mutant and with DNA gyrase protein revealed that this enzyme is not the molecular target of these compounds. The new target identification strategy involved the selection of spontaneous mutants for our lead compound 12L, characterization of this mutant strain against other 2(quinolin-4-yloxy) acetamides derivates and whole genome sequencing. Whole genome sequencing data allowed the identification of a single mutation (T313A) in the QcrB protein, which is the B subunit of cytochrome bc1 complex. This mutation was confirmed by Sanger sequencing and molecular docking results confirmed the importance of this residue for proteindrug interaction. The cytochrome bc1 complex is involved in the electron transport of the bacilli?s respiratory chain, and therefore it appears to be an interesting target, especially to treat the latent form of the disease. We hope that this work contributes to the 2(quinolin-4-yloxy) acetamides development for tuberculosis treatment. / A alta incid?ncia da tuberculose, em ?mbito mundial, ? de grande preocupa??o. Para combater esta doen?a, diferentes estrat?gias v?m sendo desenvolvidas pela Organiza??o Mundial da Sa?de (OMS). Dentre os pilares que comp?em a End TB strategy, podemos destacar a pesquisa intensiva e a inova??o. Neste ?mbito, o desenvolvimento de novos f?rmacos para tuberculose vem ganhando destaque. As 2(quinolin-4-il?xi) acetamidas s?o mol?culas que demonstraram resultados bactericidas promissores frente ao Mycobacterium tuberculosis, o que nos motivou a realizar novos estudos para melhorar a atividade e realizar a caracteriza??o qu?mica e biol?gica destas mol?culas. A fim de continuar o desenvolvimento da s?rie quinol?nica, a identifica??o do seu alvo molecular foi o foco deste trabalho. Inicialmente, levantou-se a hip?tese de que a DNA girase seria o alvo molecular, uma vez que as 2(quinolin- 5-il?xi) acetamidas possuem grande similaridade estrutural com as fluoroquinolonas. Apesar das 2(quinolin-4-il?xi) acetamidas terem apresentado menor atividade frente a isolados cl?nicos resistentes a ofloxacino, os resultados de atividade obtidos frente a uma mutante pontual de gyrA e frente ? prote?na indicam que a DNA girase n?o ? o alvo destas mol?culas. A nova estrat?gia para identifica??o de alvo envolveu a sele??o de mutantes espont?neos para o composto l?der 12L, caracteriza??o desta cepa frente aos demais compostos da s?rie e sequencimento total do genoma. Este permitiu a identifica??o de uma ?nica muta??o (T313A) localizada na prote?na QcrB, que ? a subunidade B do complexo citocromo bc1. Esta muta??o foi confirmada por sequenciamento de Sanger e o docking molecular aferiu a import?ncia deste res?duo na intera??o prote?na-composto. O complexo citocromo bc1 est? envolvido no transporte de el?trons na cadeia respirat?ria do bacilo, e por isso ? um alvo molecular interessante, principalmente para combater a forma latente da doen?a. Esperamos que este trabalho contribua no processo de desenvolvimento das 2(quinolin-4-il?xi) acetamidas para o tratamento da tuberculose.

Submitted by PPG Medicina e Ci?ncias da Sa?de (medicina-pg@pucrs.br) on 2018-03-16T19:55:06Z No. of bitstreams: 1 THA?S_CRISTINA_MURAD?S_DIS.pdf: 883340 bytes, checksum: 6481cc56bc005f400fcfc1ae75cea11e (MD5) / Approved for entry into archive by Tatiana Lopes (tatiana.lopes@pucrs.br) on 2018-03-28T13:57:53Z (GMT) No. of bitstreams: 1 THA?S_CRISTINA_MURAD?S_DIS.pdf: 883340 bytes, checksum: 6481cc56bc005f400fcfc1ae75cea11e (MD5) / Made available in DSpace on 2018-03-28T14:01:44Z (GMT). No. of bitstreams: 1 THA?S_CRISTINA_MURAD?S_DIS.pdf: 883340 bytes, checksum: 6481cc56bc005f400fcfc1ae75cea11e (MD5) Previous issue date: 2017-12-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / New effective compounds for tuberculosis (TB) treatment are currently needed. This study analyzed the anti-TB activity of a series of 16 quinoxaline-derived chalcones. From an initial in vitro screening, six molecules, namely N5, N9, N10, N15, N16, and N23 inhibited the growth of the M. tuberculosis H37Rv laboratory strain. The three compounds (N9, N15 and N23) with the lowest MIC values (3.13, 6.25, 5 ?g/mL, respectively) were further tested against clinical isolates and laboratory strains harboring mutations in katG or inhA genes. From these experimental set, N9 was selected as the lead compound for further investigations. This chalcone displayed a synergistic effect when combined with moxifloxacin, according to assessment in a checkerboard assay. Noteworthy, the anti-TB effects of N9 did not rely on inhibition of mycolic acids or non-hydroxylated fatty acids synthesis, circumventing important mechanisms of resistance in mycobacteria. Considering the safety of the tested chalcones, all the compounds behaved as substrates or inhibitors of at least one cytochrome P450 isoform, as indicated by in silico evaluation. Most compounds lacked tumorigenic, mutagenic, irritant, or reproductive effects, except N3 and N7, as shown by DataWarrior program. The chalcone N9 did not elicit any toxic alteration in doses up to 2000 mg/kg, in female mice. Based on the present results, N9 can be considered a potential candidate for development of a new anti-TB therapeutic choice. / Atualmente, s?o necess?rios novos compostos eficazes para o tratamento da tuberculose (TB). Este estudo analisou a atividade anti-TB de uma s?rie de 16 chalconas derivadas da quinoxalina. A partir de uma triagem inicial in vitro, seis mol?culas, nomeadas N5, N9, N10, N15, N16 e N23 inibiram o crescimento da cepa laboratorial de M. tuberculosis H37Rv. Os tr?s compostos (N9, N15 e N23) com os valores de MIC mais baixos (3.13, 6.25, 5 ?g/mL, respectivamente) foram testados adicionalmente contra isolados cl?nicos e cepas laboratoriais com muta??es nos genes katG ou inhA. A partir deste conjunto experimental, a chalcona quinoxal?nica N9 foi selecionada como composto principal para novas investiga??es. Esta chalcona mostrou um efeito sin?rgico quando combinada com moxifloxacino, de acordo com a avalia??o em ensaio checkerboard. Destaca-se que os efeitos anti-TB de N9 n?o dependeram da inibi??o de ?cidos mic?licos ou da s?ntese de ?cidos graxos n?o hidroxilados, envolvidos em importantes mecanismos de resist?ncia em micobact?rias. Considerando a seguran?a toxicol?gica das chalconas quinoxal?nicas testadas, todos os compostos comportaram-se como substratos ou inibidores de pelo menos uma isoforma do citocromo P450, conforme indicado pela avalia??o in silico. A maioria dos compostos n?o possui efeitos tumorig?nicos, mutag?nicos, irritantes ou reprodutivos, exceto N3 e N7, conforme demonstrado pelo programa DataWarrior. A chalcona quinoxal?nica N9 n?o provocou qualquer altera??o t?xica em doses de at? 2000 mg/kg, em camundongos f?meas. Com base nos resultados atuais, N9 pode ser considerada como potencial candidata para o desenvolvimento de uma nova escolha terap?utica anti-TB.

Submitted by PPG Biologia Celular e Molecular (bcm@pucrs.br) on 2018-03-05T13:21:28Z No. of bitstreams: 1 BRUNO_LOPES_ABBADI_TES.pdf: 4934736 bytes, checksum: 58e4c3c86d9fb96bb1476ae3c18bfdf0 (MD5) / Approved for entry into archive by Caroline Xavier (caroline.xavier@pucrs.br) on 2018-03-06T16:15:19Z (GMT) No. of bitstreams: 1 BRUNO_LOPES_ABBADI_TES.pdf: 4934736 bytes, checksum: 58e4c3c86d9fb96bb1476ae3c18bfdf0 (MD5) / Made available in DSpace on 2018-03-06T16:21:42Z (GMT). No. of bitstreams: 1 BRUNO_LOPES_ABBADI_TES.pdf: 4934736 bytes, checksum: 58e4c3c86d9fb96bb1476ae3c18bfdf0 (MD5) Previous issue date: 2018-01-19 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Epidemiologic data regarding tuberculosis (TB) show that there is still a high burden of this disease worldwide. In addition, the emergence of drug-resistant strains imposes a new threat in preventing TB spread. Therefore, it is pivotal to continuously find new candidates for drug development. In the Chapter 2 of this thesis, the compound IQG-607 is presented, which is a metal complex that has been reported as a promising anti-TB molecule against isoniazid (INH)-resistant strains of M. tuberculosis. Previous studies suggested that the compound inhibits both the wild-type NADH-dependent trans-2-enoyl-[ACP] reductase (InhA) enzyme and some of its structural mutants in the absence of NAD+ or NADH and without requiring KatG enzyme. IQG-607 has also shown a favorable toxicological profile in vivo, with a considerable lesser toxicity compared to INH. However, there is still a gap regarding the activity of IQG-607 against strains carrying mutations in the katG gene, which are the most common genetic alterations in clinical isolates resistant to INH. Therefore, this study focused in elucidating the mechanism of resistance (MOR) of the Mycobacterium tuberculosis, the main causative agent of TB, to compound IQG-607. First the minimum inhibitory concentration (MIC) of IQG-607 was established against eight multi-drug resistant (MDR) clinical isolates, which were resistant to our compound. Then spontaneous mutants were selected using high concentrations of compound in 7H10 agar medium, and their whole genomes were sequenced; the results revealed alterations in the katG gene. A laboratory strain carrying the mutant katG(S315T) gene was developed to assess the effect of this single mutation in the compound activity both by MIC determination and by a macrophage infection model. Results showed that this mutation was indeed sufficient to confer resistance to IQG-607. Finally, the resistance observed for a strain expressing a mutant InhA(S94A) protein suggested that IQG-607 has this enzyme as its molecular target. In the Chapter 3, two new compounds, called Labio-16 and Labio-17, are presented, which were previously selected to interact and inhibit the InhA enzyme and that had already shown to be active against M. tuberculosis H37Rv strain. A set of experiments were conducted to elucidate their mechanism of action (MOA) and to understand the MOR of the M. tuberculosis against them, similar to those carried for studying IQG-607. So far, results suggested that the InhA is not the molecular target of these compounds. Other experiments are undergoing in our laboratory to evaluate in a murine model of TB infection their potential as anti-TB drug candidates. / Os dados epidemiol?gicos relacionados ? tuberculose (TB) indicam que ainda existe uma carga elevada desta doen?a no mundo todo. Al?m disso, o surgimento de cepas resistentes aos f?rmacos imp?e uma nova amea?a na preven??o da propaga??o da TB. Portanto, ? fundamental buscar continuamente novos candidatos para o desenvolvimento de medicamentos. No Cap?tulo 2 desta tese ? apresentado o composto IQG-607, que ? um complexo met?lico que tem sido reportado como uma mol?cula anti-TB promissora contra cepas de M. tuberculosis resistentes ? isoniazida (INH). Estudos pr?vios sugeriram que o composto inibe a enzima selvagem trans-2-enoil-[ACP] redutase dependente de NADH (InhA) e algumas das suas mutantes estruturais, na aus?ncia de NAD+ ou NADH e sem necessitar da enzima KatG. O IQG-607 tamb?m mostrou um perfil toxicol?gico favor?vel in vivo, com uma menor toxicidade em compara??o ? INH. No entanto, ainda existe uma lacuna em rela??o ? atividade do IQG-607 contra cepas que carregam muta??es no gene katG, as quais s?o as altera??es gen?ticas mais comuns em isolados cl?nicos resistentes ? INH. Sendo assim, este estudo focou em elucidar o mecanismo de resist?ncia (MOR) do Mycobacterium tuberculosis, o principal agente causador da TB, ao composto IQG-607. Primeiramente, a concentra??o inibit?ria m?nima (MIC) do IQG-607 foi estabelecida contra oito isolados cl?nicos multirresistentes a f?rmacos (MDR), os quais foram resistentes ao nosso composto. Ent?o, mutantes espont?neos foram selecionados, usando-se altas concentra??es do composto em meio ?gar 7H10, e seus genomas completos foram sequenciados; os resultados revelaram altera??es no gene katG. Uma cepa laboratorial, carregando o gene katG(S315T) mutante, foi desenvolvida para acessar o efeito desta ?nica muta??o na atividade do composto, atrav?s da determina??o de MIC e por meio de um modelo de infec??o de macr?fagos. Os resultados mostraram que essa muta??o de fato foi suficiente para conferir resist?ncia ao IQG-607. Finalmente, a resist?ncia observada para a cepa que expressa a prote?na InhA(S94A) mutante sugeriu que o IQG-607 tem esta enzima como seu alvo molecular. No Cap?tulo 3, dois novos compostos, denominados Labio-16 e Labio-17, s?o apresentados, os quais foram previamente selecionados para interagir e inibir a enzima InhA, e que j? tinham mostrado ser ativos contra a cepa H37Rv de M. tuberculosis. Um conjunto de experimentos foi conduzido para elucidar os seus mecanismos de a??o (MOA) e para compreender o MOR do M. tuberculosis contra eles, similar ?quele usado para estudar o IQG-607. At? o momento, os resultados sugerem que a InhA n?o ? o alvo molecular desses compostos. Outros experimentos est?o em andamento em nosso laborat?rio, para avaliar em um modelo murino da infec??o da TB os seus potenciais como candidatos a f?rmacos anti-TB.