In recent decades, transmission of Trypanosoma cruzi, the causative agent of Chagas disease, by Triatoma infestans and other vector insects has expanded from historically rural areas to urban centers across Latin America. The urbanization of the T. cruzi transmission cycle necessitates new understanding of Chagas disease ecology and epidemiology, as well as new approaches to the surveillance, control, and prevention of vector infestation and parasite transmission. In rural La Joya, Peru, analyses highlight how the complexities of human migration and intermittent intervention influence the prevalence and incidence of Chagas disease. Substantial prevalence of T. cruzi infection was found in the adult population as a result of relatively higher incidence of infection among long-term inhabitants and relatively lower incidence of infection among short-term in-migrants. While an insecticide intervention in 1995 effectively eliminated incidence of infection among children, T. infestans and T. cruzi were rapidly reemerging in the absence of continuing vector control. In Arequipa, Peru, T. infestans had extensively and intensively infested an urban and peri-urban landscape prior to vector control. Environmental and social factors, which may directly or indirectly influence insect biology and behavior, were associated with infestation. Large clusters of infestation and spatial dependence among infested households at short and long distances suggest that T. infestans can disperse by crawling or flying in an urban environment, which may challenge ongoing vector surveillance and control. Reemergence of vector insects, including T. infestans, complicates continuing control of Chagas disease. While relatively rare, reemergence of T. infestans is a present and possibly persistent problem in urban and peri-urban Arequipa. The probability of a reemergence event varied spatially. Events were both clustered and non-clustered, and were spatially dependent at distances up to 1,600 meters. Event-to-event spatial proximity occurred at shorter distances in higher risk areas and longer distances in lower risk areas. Identifiable predictors and patterns of risk offer opportunities for more effective and efficient strategies for vector surveillance and control.

In insects, ecdysis is an important feature of growth and development and is tightly controlled by a variety of neuropeptides. In holometabolous insects, crustacean cardioactive peptide (CCAP) is one of many factors that regulate ecdysis behaviours; however, not much is known about the control of ecdysis in hemimetabolous insects. In this thesis, the CCAP-signaling pathway is shown to be essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus. The cDNA sequence of the CCAP gene has been cloned from the R. prolixus central nervous system (CNS) and the functional role of CCAP as a neuromodulator/neurotransmitter demonstrated. Specifically, the expression of RhoprCCAP in CNS neurons producing extensive CCAP-like immunoreactive processes within the neuropile indicates that CCAP plays central roles in coordination of other neurons. RhoprCCAP also acts as a neurohomone/neuromodulator released peripherally to coordinate many tissues. Thus, CCAP-like immunoreactive processes are found in neurohemal sites and also on peripheral tissues. The RhoprCCAP receptor (RhoprCCAPR) has been cloned and shown to be a G-protein coupled receptor (GPCR). RhoprCCAPR expression is observed in the CNS and certain peripheral tissues of R. prolixus. Also, CCAP stimulates hindgut contractions and increases the heartbeat rate in a dose-dependent manner. The involvement of CCAP in R. prolixus ecdysis has been investigated. Up-regulation of the RhoprCCAP transcript in the CNS and the RhoprCCAP receptor (RhoprCCAPR) transcript in the CNS and specific peripheral tissues was observed immediately prior to ecdysis. Also, decreasing staining intensity of CCAP-like immunoreactivity in neurons immediately following ecdysis indicates the release of CCAP during ecdysis. The critical importance of the CCAP-signalling pathway was further demonstrated by knockdown of the RhoprCCAP and RhoprCCAPR transcripts utilizing double stranded RNA interference. Insects with these transcripts knocked down have high mortality (up to 84%), typically at the expected time of ecdysis, or have ecdysis extremely delayed. Taken together, this thesis demonstrates that RhoprCCAP plays a crucial role in regulating ecdysis behaviours in R. prolixus, and clearly shows the conserved nature of the CCAP-signaling pathway in ecdysis for both holometabolous and hemimetabolous insects.

In insects, ecdysis is an important feature of growth and development and is tightly controlled by a variety of neuropeptides. In holometabolous insects, crustacean cardioactive peptide (CCAP) is one of many factors that regulate ecdysis behaviours; however, not much is known about the control of ecdysis in hemimetabolous insects. In this thesis, the CCAP-signaling pathway is shown to be essential for successful ecdysis in the hemimetabolous insect, Rhodnius prolixus. The cDNA sequence of the CCAP gene has been cloned from the R. prolixus central nervous system (CNS) and the functional role of CCAP as a neuromodulator/neurotransmitter demonstrated. Specifically, the expression of RhoprCCAP in CNS neurons producing extensive CCAP-like immunoreactive processes within the neuropile indicates that CCAP plays central roles in coordination of other neurons. RhoprCCAP also acts as a neurohomone/neuromodulator released peripherally to coordinate many tissues. Thus, CCAP-like immunoreactive processes are found in neurohemal sites and also on peripheral tissues. The RhoprCCAP receptor (RhoprCCAPR) has been cloned and shown to be a G-protein coupled receptor (GPCR). RhoprCCAPR expression is observed in the CNS and certain peripheral tissues of R. prolixus. Also, CCAP stimulates hindgut contractions and increases the heartbeat rate in a dose-dependent manner. The involvement of CCAP in R. prolixus ecdysis has been investigated. Up-regulation of the RhoprCCAP transcript in the CNS and the RhoprCCAP receptor (RhoprCCAPR) transcript in the CNS and specific peripheral tissues was observed immediately prior to ecdysis. Also, decreasing staining intensity of CCAP-like immunoreactivity in neurons immediately following ecdysis indicates the release of CCAP during ecdysis. The critical importance of the CCAP-signalling pathway was further demonstrated by knockdown of the RhoprCCAP and RhoprCCAPR transcripts utilizing double stranded RNA interference. Insects with these transcripts knocked down have high mortality (up to 84%), typically at the expected time of ecdysis, or have ecdysis extremely delayed. Taken together, this thesis demonstrates that RhoprCCAP plays a crucial role in regulating ecdysis behaviours in R. prolixus, and clearly shows the conserved nature of the CCAP-signaling pathway in ecdysis for both holometabolous and hemimetabolous insects.

Diss. (sammanfattning) Uppsala : Univ., 2003. / Härtill 4 uppsatser.

Thesis (M.Sc.). / Written for the Dept. of Microbiology and Immunology. Title from title page of PDF (viewed 2008/05/28). Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 132-145).

A doença de Chagas, transmitida pelo protozoário Trypanosoma cruzi, afeta mais de 18 milhões de pessoas na América Latina e mesmo tendo sido descrita há 100 anos por Carlos Chagas, esta ainda representa um importante problema de saúde pública, sendo encontrados casos em 18 países em desenvolvimento na América do Sul e Central. No Brasil, o benzonidazol, (ROCHAGAN), é a única droga de atividade tripanocida disponível no mercado mesmo apresentando vários efeitos colaterais e limitada eficácia na fase crônica da infecção. Em vista da necessidade de novas substâncias com atividade biológica sobre T.cruzi, o interesse pela pesquisa vem crescendo com o intuito de se obter compostos capazes de atuarem sobre o parasita, desprovidos dos graves efeitos colaterais. Estudos desenvolvidos em nosso laboratório envolvendo lignanas demonstraram uma importante atividade destes compostos sobre as formas tripomastigotas sanguíneas. Assim este estudo tem como objetivo avaliar a atividade terapêutica de derivados de lignana dibenzilbutirolactônicas em sistema in vivo, em fase aguda e crônica da infecção por T. cruzi. Como critérios de estudo avaliamos o comportamento parasitêmico dos animais na fase aguda, quantificamos a enzima -galactosidase nos tecidos do fígado, baço e coração além da análise morfométrica dos tecidos. Com relação à parasitemia, dos animais na fase aguda, as substâncias cubebina e hinoquina, apresentaram significante redução parasitêmica comparado ao controle negativo e melhor atividade no tratamento pela via oral. Na análise por caracterização de -galactosidase, as substâncias apresentaram melhores resultados comparados ao controle positivo (Benzonidazol) e também melhor eficácia da resposta para o tratamento pela via oral. Nos resultados apresentados pela cariometria os grupos de tratamento com as substâncias cubebina e hinoquinina apresentaram valores próximos ao controle não infectado, mostrando que ocorreu uma resposta celular positiva comparado ao controle infectado. / Chagas disease, transmitted by the protozoan Trypanosoma cruzi, affects over 18 million people in Latin America. Even though it was described 100 years ago by Carlos Chagas, it still represents a major public health problem, and there are cases in 18 developing countries located in Central and South America. In Brazil, benznidazole (Rochagan) is the only trypanocidal drug available in the market; however, it has several side effects and limited efficacy in the chronic phase of the infection. In view of the need for new substances with biological activity against T. cruzi, there is growing interest in the search for compounds capable of acting on the parasite, but are devoid of serious side effects. Studies involving lignans developed in our laboratory have shown that these compounds are significantly active against bloodstream trypomastigotes. So this study aims to evaluate the therapeutic activity of derivatives of dibenzylbutyrolactone lignans in vivo, in the acute and chronic infection by T. cruzi. The present study examined the degree of parasitemia in the infected animals during the acute phase of the disease. To this end, the enzyme -galactosidase was measured in the tissues from the liver, spleen, and heart of infected animals, in addition to the morphometric analysis of these tissues. Cubebin and hinokinin led to significant reduction in parasitemia compared to the negative control, and better treatment was accomplished by the oral route. Concerning -galactosidase analysis, cubebin and hinokinin furnished better results compared to the positive control (Benznidazole), the most effective response to treatment being also achieved by oral route. Karyometry also revealed that cubebin and hinokinin were effective, giving values close to those obtained with the uninfected control, thereby showing that there was a positive cellular response.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2013-10-18T18:15:09Z No. of bitstreams: 1 Murilo F. Castro. Avaliação da atividade,,, 2012.pdf: 1468986 bytes, checksum: 7b9241cb49aba27e80628022c24eb12a (MD5) / Made available in DSpace on 2013-10-18T18:15:09Z (GMT). No. of bitstreams: 1 Murilo F. Castro. Avaliação da atividade,,, 2012.pdf: 1468986 bytes, checksum: 7b9241cb49aba27e80628022c24eb12a (MD5) Previous issue date: 2012 / Fundação Oswaldo Cruz. Centro de Pesquisas Gonçalo Moniz. Salvador, BA, Brasil / A doença de Chagas (DC) é considerada um agravo ainda negligenciado. Atualmente, estima-se cerca de 10 milhões de pessoas infectadas pelo Trypanosoma cruzi, em todo o mundo, principalmente na América Latina. Sabe-se que alguns derivados de naftoquinonas podem agir sobre a tripanotiona redutase (TR), enzima específica dos tripanossomatídeos responsável pelo controle oxidativo celular. A inibição da TR favorece um processo oxidativo e morte do protozoário. Este trabalho teve como objetivo investigar o potencial anti-T.cruzi da fitomenadiona, (K1) e menadiona (K3), ambas vitaminas K derivadas de naftoquinonas. Com este propósito, o efeito tripanocida de K1 e K3 foi avaliado através de ensaios in vitro com as formas tripomastigotas e epimastigotas do T. cruzi nas cepas Colombiana e Y utilizando os testes de inibição, citotoxicidade dos compostos, ensaio de infecção em macrófagos, avaliação de alterações ultraestruturais, bem como ensaio em in vivo para avaliação na redução da parasitemia. Os valores de IC50 mais significativos para formas tripomastigotas do T. cruzi foram 27,55 μM para K1, 2,19 μM para K3 e 12,46 μM para o benzonidazol, a droga padrão. Contudo, o tratamento com a vitamina K1 não reduziu a parasitemia in vivo, que permaneceu alta assim como a do controle tratado com veículo. A vitamina K3 foi capaz de inibir ambas as cepas e diferentes formas do parasito em ensaios in vitro. No ensaio de infecção de macrófagos, a vitamina K3 em concentração de 21,4 μM inibiu de forma mais significativa a infecção de células em relação à droga padrão, em concentração de 38,4 μM. Apesar da citotoxicidade mais elevada, esta droga apresentou uma seletividade maior ao parasito do que a células de mamíferos e, em baixas doses, causou a redução na parasitemia in vivo. As avaliações ultraestruturais por microscopia eletrônica de transmissão evidenciaram alterações celulares induzidas por estes compostos, destacando-se a tumefação do cinetoplasto e a presença de vacúolos. A quantificação ultraestrutural na avaliação por microscopia eletrônica de varredura demonstrou alterações em cerca de 80% dos parasitos observados quando tratados com K3 a 5 μM. Nossos resultados demonstram o efeito anti-T. cruzi das moléculas testadas e sugerem que estas possam servir de base para o desenho de novos compostos candidatos a fármacos para o tratamento da doença de Chagas. / Chagas disease (AD) is considered a neglected disease. Currently, it is estimated 10 million people infected with Trypanosoma cruzi, worldwide, mostly in Latin America. It is known that some derivatives of naphthoquinones can act on the trypanothione reductase (TR), specific enzyme of trypanosomatids responsible for controlling oxidative stress. Inhibition of TR favors an oxidative process and death of the parasite. This work aimed to investigate the potential anti-T. cruzi of phytomenadione, (K1) and menadione (K3), both vitamin K derived from naphthoquinones. For this purpose, the trypanocidal effect of K1 and K3 was evaluated by in vitro assays with epimastigotes and trypomastigotes of T. cruzi in strains Colombian and Y using the inhibition tests, cytotoxicity of compounds of infection in macrophages test, evaluation of ultrastructural alterations as well as in vivo test to evaluate the reduction of the parasitemia. The best IC50 values to trypomastigote forms of T. cruzi were 27.55 μM to K1 and 2.19 μM to K3, compared to 12.46 μM of benznidazole, the standard drug. However, the treatment with vitamin K1 did not reduce parasitemia in vivo, which remains high similar to the vehicletreated control group. Vitamin K3 was able to inhibit both strains and different forms of the parasite in in vitro assays. In macrophage infection assay, vitamin K3 at a concentration of 21.4 μM significantly inhibited T. cruzi infection of cells when compared to the standard drug (benznidazole) in a concentration of 38.4 μM. Although this compound had a high cytotoxicity, vitamin K3 showed greater selectivity than the parasite mammalian cells, and in a low dose caused a reduction in parasitemia in vivo. The ultrastructural evaluation by transmission electron microscopy revealed cellular alterations induced by these compounds, especially the swelling of the kinetoplast and the presence of vacuoles. The ultrastructural quantification in the evaluation by scanning electron microscopy showed changes in about 80% of parasites observed when treated with 5 μM K3. Our results demonstrate the anti-T. cruzi molecules tested, suggesting that they may serve as a basis for designing new drug candidate compounds for the treatment of Chagas disease.

Submitted by Ana Maria Fiscina Sampaio (fiscina@bahia.fiocruz.br) on 2014-02-07T18:23:30Z No. of bitstreams: 1 Renata Siqueira Portella.. Presença de células....pdf: 2025004 bytes, checksum: a85d3195f20f2a79bd6ff1b32049c260 (MD5) / Made available in DSpace on 2014-02-07T18:23:30Z (GMT). No. of bitstreams: 1 Renata Siqueira Portella.. Presença de células....pdf: 2025004 bytes, checksum: a85d3195f20f2a79bd6ff1b32049c260 (MD5) Previous issue date: 2013 / Fundação Oswaldo Cruz. Centro de Pesquisa Gonçalo Moniz. Salvador, BA, Brasil / Universidade Federal da Bahia. Faculdade de Medicina. Salvador, BA, Brasil / A doença de Chagas é caracterizada por apresentar duas fases com curso clínico bastante variável. Na fase aguda ocorre uma intensa miocardite, sendo o parasita facilmente detectado no sangue periférico e nos tecidos. A fase crônica cardíaca é caracterizada por uma cardiopatia, com intensa destruição das fibras cardíacas, presença de áreas de fibrose e escassos parasitas. Os mecanismos envolvidos na patogenia dessa miocardite ainda não são muito claros. Acredita-se que as células reguladoras e as células dendríticas estejam envolvidas nesse processo. Para compreender os mecanismos envolvidos, na resposta inflamatória à infecção pelo T. cruzi, resolvemos investigar a participação das células dendríticas, das células reguladoras e o perfil dos linfócitos T CD4+ e CD8+, utilizando duas linhagens de camundongos isogênicos, que apresentam diferentes graus de susceptibilidade a infecção. Em nossos resultados constatamos que os camundongos DBA/1 apresentaram maior sobrevida à fase aguda (90%), mesmo tratando os camundongos A (70%) com benzonidazol por três dias consecutivos, com o intuito de diminuir a carga parasitária prevenindo a alta mortalidade. A resistência dos DBA/1 e a susceptibilidade dos A, a infecção pelo T. cruzi, estaria relacionada ao perfil da resposta inflamatória e regulatória desenvolvida no decorrer da doença. Observamos que os camundongos DBA/1 possuem mais células dendríticas ativadas no baço e coração e mais células T CD4+CD25hi do que os camundongos da linhagem A. Essa diferença do perfil de resposta pode estar provocando uma maior expansão e diferenciação dos linfócitos T CD4+ pelas células dendríticas, levando ao controle da carga parasitaria. / Chagas’diseasse, due to Trypanosoma cruzi infection is characterized by the development of two phases with a variable clinical course. During the acute phase there occurs a severe myocarditis with the parasite being easily detected in peripheral blood and tissues. The chronic cardiac phase is characterized as a chronic cardiopathy, when severe destruction of cardiac myocells and fibrosis are present and parasites are rare. The mechanisms involved in the pathogenesis of this myocarditis are somewhat obscure. It is believed that regulatory and dendritic cells play a role in this process. In an attempt to clarify the mechanisms involved in the inflammatory response to infection with T. cruzi we decided to investigate the participation of dendritic and regulatory cells and of TCD4 and TCD8 lymphocytes, using two strains of isogenic mice , which exhibit different degrees of susceptibility to infection. Our results have shown that the DBA/1 mice presented a higher survival (90%) in the acute phase than the A mice (70%), even when these were treated with Benznidazole for three consecutive days, with the objective of to reduce the parasitemia and the high mortality. Resistance of DBA/1 mice and susceptibility of A mice could be related to the evolution of the inflammatory and regulatory responses, during the infection. It was seen that DBA/1 mice disclosed a higher number of activated dendritic cells in the spleen and heart and a higher number of T CD4+CD25hi than the mice of A strain. This differences of the response could be influencing in the TCD4 differentiation and on the control of parasitic load

Neglected diseases constitute a major public health problem worldwide, quantifying a total of 1 billion people suffering from some kind of infection of bacterial, viral or parasitic origin. Among them, we can highlight Chagas disease, caused by the parasite Trypanosoma cruzi, which affects more than 8 million people around the world. In order to discover new active compounds against T. cruzi, developed herein the synthesis of new prototypes of thiophene-2- thioureic and 2-iminothiazolidine rationally designed with potential antichagasic activity, biological evaluation and study docking. Initially, the start material was the polysubstituted thiophene derivatives synthesized via Gewald reaction, which were converted into thioureic derivatives and then cyclized with five different electrophiles, generating thiophene-2- iminothiazolidine derivatives. The intermediates and final compounds were synthesized in yields between 40 and 98%, and characterized by NMR. For docking study was initially performed by minimizing the energy of the ligands by ArgusLab® software, using AM1, and applying the software AutoDock Tools® and AutoDock Vina®, using the Gasteiger method. All compounds were evaluated in the anti-T. cruzi assays, in vitro, and the most active serie was selected for the cytotoxicity assay (MTT) in J774 cell line. It was possible to determine the enzymes involved in the probable mechanisms of action for the ligands. It has been observed that in 50% of cases, TcDHFR enzyme is the main target of the new compounds, in amastigotes. The pharmacological tests in amastigotes and trypomastigotes, line of C2C12 and MK2 cells was established as validation for the theoretical studies. The compound 3d probably develops its mechanism of action by inhibition of the enzyme TcTS (IC50= 10.3 µM) in trypomastigotes of the parasite. Since the compound 7c possibly acts by inhibition of the enzyme TcDHFR (IC50= 9.2 µM) in amastigotes. In additional, it was proposed that the compound 7b carries out its activity by inhibition of the enzyme TcDHFR (IC50 = 5.0 µM). Finally, it was observed that the most active compounds obtained in this study were more effective than the benznidazole, gold standard drug used in pharmacotherapy clinical of the Chagas disease, additionally has a low cytotoxicity (CC50> 100 µM). / As doenças negligenciadas configuram um grande problema de saúde pública mundial, quantificando um total de 1 bilhão de pessoas acometidas por algum tipo de infecção de origem bacteriana, viral ou parasitária. Dentre elas, podemos destacar a Doença de Chagas, causada pelo parasito Trypanosoma cruzi, a qual acomete mais de 8 milhões de pessoas em todo o mundo. No intuito de se descobrir novos compostos ativos capazes de combater o T. cruzi de maneira eficaz, desenvolvemos neste trabalho a síntese de novos protótipos de fármacos tiofeno-2-tioureicos e 2-iminotiazolidínicos racionalmente planejados com potencial atividade antichagásica, avaliação biológica e estudo de docking. Para a síntese dos compostos planejados, partiu-se de derivados tiofenos polissubstituídos, sintetizados via reação de Gewald, os quais foram convertidos em derivados tioureicos e, em seguida, ciclizados com cinco diferentes di-eletrófilos, gerando derivados tiofeno-2- iminotiazolidínicos. Os intermediários e compostos finais foram sintetizados com rendimentos entre 40 e 98%, e caracterizados por RMN. Para o estudo de docking, inicialmente foi realizada a minimização das energias dos ligantes pelo software ArgusLab®, usando o método AM1, e aplicando os softwares AutoDock Tools® e AutoDock Vina®, empregando o método de Gasteiger. Todos os compostos foram submetidos à avaliação in vitro de suas atividades anti-T. cruzi, e a série mais ativa foi selecionada para ensaio de citotoxicidade (MTT) em células da linhagem J774. Foi possível determinar as enzimas envolvidas nos prováveis mecanismos de ação para os ligantes. Foi observado que, em 50% dos casos, a enzima TcDHFR é o principal alvo dos novos composto, em formas amastigotas. Os ensaios farmacológicos em formas amastigotas e tripomastigotas, linhagem de células C2C12 e MK2 funcionaram como métodos de validação dos estudos teóricos. O composto 3d, provavelmente desenvolve seu mecanismo de ação através da inibição da enzima TcTS (IC50= 10.3 µM), em formas tripomastigotas do parasito. Já o composto 7c,possivelmente atua por meio da inibição da enzima TcDHFR (IC50= 9.2 µM) em formas amastigotas. Em adicional, foi proposto que o composto 7b desenvolve sua atividade através da inibição da enzima TcDHFR (IC50= 5.0 µM). Por fim, foi verificado que os compostos mais ativos obtidos neste trabalho se mostraram mais eficientes do que o fármaco benznidazol, padrão-ouro utilizado na clínica farmacológica da doença de Chagas, além destes apresentarem baixa citotoxicidade (CC50> 100 µM).