Identification of cisapride as new inhibitor of putrescine uptake in Trypanosoma cruzi by combined ligand- and structure-based virtual screening

Nowadays, the pharmacological therapy for the treatment of Chagas disease is based on two old drugs, benznidazole and nifurtimox, which have restricted efficacy against the chronic phase of the illness. To overcome the lack of efficacy of the traditional drugs (and their considerable toxicity), new molecular targets have been studied as starting points to the discovery of new antichagasic compounds. Among them, polyamine transporter TcPAT12 (also known as TcPOT1.1) represents an interesting macromolecule, since polyamines are essential for Trypanosoma cruzi, the parasite that causes the illness, but it cannot synthesize them de novo. In this investigation we report the results of a combined ligand- and structure-based virtual screening for the discovery of new inhibitors of TcPAT12. Initially we filtered out ZINC and Drugbank databases with similarity and QSAR models and then we submitted the candidates to a validated docking based screening. Four structures were selected and tested in T. cruzi epimastigotes proliferation and two of them, Cisapride and [2-(cyclopentyloxy)phenyl]methanamine showed inhibitory effects. Additionally, we performed transport assays which demonstrated that Cisapride interferes with putrescine uptake in a specific mode.Fil: Dietrich, Roque Carlos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación y Desarrollo de Bioactivos; ArgentinaFil: Alberca, Lucas Nicolás. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación y Desarrollo de Bioactivos; ArgentinaFil: Ruiz, María Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Palestro, Pablo Hernán. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación y Desarrollo de Bioactivos; ArgentinaFil: Carrillo, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Talevi, Alan. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación y Desarrollo de Bioactivos; Argentin

Identification of cisapride as new inhibitor of putrescine uptake in Trypanosoma cruzi by combined ligand- and structure-based virtual screening

Nowadays, the pharmacological therapy for the treatment of Chagas disease is based on two old drugs, benznidazole and nifurtimox, which have restricted efficacy against the chronic phase of the illness. To overcome the lack of efficacy of the traditional drugs (and their considerable toxicity), new molecular targets have been studied as starting points to the discovery of new antichagasic compounds. Among them, polyamine transporter TcPAT12 (also known as TcPOT1.1) represents an interesting macromolecule, since polyamines are essential for Trypanosoma cruzi, the parasite that causes the illness, but it cannot synthesize them de novo. In this investigation we report the results of a combined ligand- and structure-based virtual screening for the discovery of new inhibitors of TcPAT12. Initially we filtered out ZINC and Drugbank databases with similarity and QSAR models and then we submitted the candidates to a validated docking based screening. Four structures were selected and tested in T. cruzi epimastigotes proliferation and two of them, Cisapride and [2-(cyclopentyloxy)phenyl]methanamine showed inhibitory effects. Additionally, we performed transport assays which demonstrated that Cisapride interferes with putrescine uptake in a specific mode.Laboratorio de Investigación y Desarrollo de Bioactivo

Cascade ligand- and structure-based virtual screening to identify new trypanocidal compounds inhibiting putrescine uptake

Chagas disease is a neglected tropical disease endemic to Latin America, though migratory movements have recently spread it to other regions. Here, we have applied a cascade virtual screening campaign combining ligand- and structure-based methods. In order to find novel inhibitors of putrescine uptake in Trypanosoma cruzi, an ensemble of linear ligand-based classifiers obtained by has been applied as initial screening filter, followed by docking into a homology model of the putrescine permease TcPAT12. 1,000 individual linear classifiers were inferred from a balanced dataset. Subsequently, different schemes were tested to combine the individual classifiers: MIN operator, average ranking, average score, average voting, with MIN operator leading to the best performance. The homology model was based on the arginine/agmatine antiporter (AdiC) from Escherichia coli as template. It showed 64% coverage of the entire query sequence and it was selected based on the normalized Discrete Optimized Protein Energy parameter and the GA341 score. The modeled structure had 96% in the allowed area of Ramachandran's plot, and none of the residues located in non-allowed regions were involved in the active site of the transporter. Positivity Predictive Value surfaces were applied to optimize the score thresholds to be used in the ligand-based virtual screening step: for that purpose Positivity Predictive Value was charted as a function of putative yields of active in the range 0.001-0.010 and the Se/Sp ratio. With a focus on drug repositioning opportunities, DrugBank and Sweetlead databases were subjected to screening. Among 8 hits, cinnarizine, a drug frequently prescribed for motion sickness and balance disorder, was tested against T. cruzi epimastigotes and amastigotes, confirming its trypanocidal effects and its inhibitory effects on putrescine uptake. Furthermore, clofazimine, an antibiotic with already proven trypanocidal effects, also displayed inhibitory effects on putrescine uptake. Two other hits, meclizine and butoconazole, also displayed trypanocidal effects (in the case of meclizine, against both epimastigotes and amastigotes), without inhibiting putrescine uptake.Facultad de Ciencias ExactasLaboratorio de Investigación y Desarrollo de Bioactivo

Benznidazol associado a outros fármacos para o tratamento da doença de Chagas

Trabalho de Conclusão de Curso (graduação)—Universidade de Brasília, Faculdade de Ceilândia, 2018.Introdução: a doença de Chagas é uma doença parasitária endêmica na América Latina, com cerca de 6 a 7 milhões de pessoas infectadas. Embora descoberta a mais de 100 anos seu tratamento limita-se ao Benznidazol e Nifurtimox, dois nitro-imidazóis de eficácia limitada que promovem uma série de efeitos adversos importantes. Objetivo: o presente trabalho busca evidências que apontam para uma melhora na terapêutica da doença por meio da associação de Benznidazol a outros fármacos. Metodologia: para tal foi realizado uma revisão de artigos indexados nas principais bases de dados, em busca de trabalhos que abordam a associação do Benznidazol a outros fármacos no tratamento dessa enfermidade. Em seguida foi realizada a extração padronizada dos dados, análise criteriosa dos resultados e agrupamento em classes. Resultados: foram encontrados um total de 17 artigos dos quais 6 deles associados a Benznidazol resultaram em cura, no entanto, outros efeitos sinérgicos foram detectados em boa parte das associações como redução da parasitemia, diminuição dos danos cardíacos e aumento da atividade motora e exploratória em murinos. Consideração final: foi possível concluir que os resultados apontam evidências que no futuro podem resultar em terapêuticas mais eficazes, entretanto, os resultados evidenciam em boa parte efeitos sinérgicos expressivos, mas tratam-se de estudos pré-clínicos que precisam seguir em direção as demais fases da pesquisa clínica.Introduction: Chagas' disease is an endemic parasitic disease in Latin America, with about 6 to 7 million people infected. Although discovered more than 100 years ago, its treatment is limited to Benznidazole and Nifurtimox, two limited-effectiveness nitroheterocyclics that promote a number of important adverse effects. Objective: the present work seeks evidence to show an improvement in the treatment of chagas' disease through the association of BZ with other drugs. Methodology: a review of articles indexed in the main databases, then standardized extraction of the data, careful analysis of the results and grouping in classes. Results: a total of 21 articles were found, 6 of them associated with BZ resulted in cure; however, other synergistic effects were detected in most of the associations, such as reduction of parasitemia, reduction of cardiac damage and increased motor and exploratory activity in murine. Final considerations: although the results show a significant synergistic effect, these are preclinical studies that need to follow the other phases of clinical research

Review of pharmacological options for the treatment of Chagas disease

Chagas disease (CD) is a worldwide problem, with over 8 million people infected in both rural and urban areas. CD was first described over a century ago, but only two drugs are currently available for CD treatment: benznidazole (BZN) and nifurtimox (NF). Treating CD-infected patients, especially children and women of reproductive age, is vital in order to prevent long-term sequelae, such as heart and gastrointestinal dysfunction, but this aim is still far from being accomplished. Currently, the strongest data to support benefit–risk considerations come from trials in children. Treatment response biomarkers need further development as serology is being questioned as the best method to assess treatment response. This article is a narrative review on the pharmacology of drugs for CD, particularly BZN and NF. Data on drug biopharmaceutical characteristics, safety and efficacy of both drugs are summarized from a clinical perspective. Current data on alternative compounds under evaluation for CD treatment, and new possible treatment response biomarkers are also discussed. Early diagnosis and treatment of CD, especially in paediatric patients, is vital for an effective and safe use of the available drugs (i.e. BZN and NF). New biomarkers for CD are urgently needed for the diagnosis and evaluation of treatment efficacy, and to guide efforts from academia and pharmaceutical companies to accelerate the process of new drug development

Review of pharmacological options for the treatment of Chagas disease

Chagas disease (CD) is a worldwide problem, with over 8 million people infected in both rural and urban areas. CD was first described over a century ago, but only two drugs are currently available for CD treatment: benznidazole (BZN) and nifurtimox (NF). Treating CD-infected patients, especially children and women of reproductive age, is vital in order to prevent long-term sequelae, such as heart and gastrointestinal dysfunction, but this aim is still far from being accomplished. Currently, the strongest data to support benefit–risk considerations come from trials in children. Treatment response biomarkers need further development as serology is being questioned as the best method to assess treatment response. This article is a narrative review on the pharmacology of drugs for CD, particularly BZN and NF. Data on drug biopharmaceutical characteristics, safety and efficacy of both drugs are summarized from a clinical perspective. Current data on alternative compounds under evaluation for CD treatment, and new possible treatment response biomarkers are also discussed. Early diagnosis and treatment of CD, especially in paediatric patients, is vital for an effective and safe use of the available drugs (i.e. BZN and NF). New biomarkers for CD are urgently needed for the diagnosis and evaluation of treatment efficacy, and to guide efforts from academia and pharmaceutical companies to accelerate the process of new drug development.Fil: Lascano, María Fernanda. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; ArgentinaFil: García Bournissen, Facundo. Public Health Ontario; CanadáFil: Altcheh, Jaime Marcelo. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; Argentina. Gobierno de la Ciudad de Buenos Aires. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto Multidisciplinario de Investigaciones en Patologías Pediátricas; Argentin

Tratamento farmacológico da Doença de Chagas e suas perspectivas

Trabalho de conclusão de curso (graduação)—Universidade de Brasília, Faculdade de Ciências da Saúde, Curso de Farmácia, 2017.A doença de Chagas, descoberta há mais de 100 anos pelo médico sanitarista brasileiro Carlos Chagas, é considerada uma doença negligenciada, afetando principalmente populações com baixo desenvolvimento socioeconômico. Estima-se que em 2016, 6-8 milhões de pessoas na América Latina estariam infectadas com o T. cruzi, agente etiológico da doença. Apesar dos seus impactos, a enfermidade permanece sem tratamento eficiente. Como evidenciado pelo recente estudo BENEFIT, o fármaco considerado como referência (benznidazol) possui atividade limitada, especialmente sobre a fase crônica da doença. Este trabalho teve por objetivo avaliar, através de revisão de literatura, o tratamento atual da doença e apresentar as novas alternativas farmacológicas que estão em fase de pesquisa. Os artigos foram divididos de acordo com a sua estratégia de desenvolvimento, sendo: avaliação da terapia atual pelos fármacos benznidazol e nifurtimox, pesquisa por novas drogas, reposicionamento de fármacos, associação de fármacos, comparação de compostos com atividade anteriormente descrita, e pesquisa em biblioteca de compostos. É possível concluir que muitos desafios necessitam ser superados para o desenvolvimento de uma alternativa farmacológica para doença de Chagas, pois o processo de pesquisa e desenvolvimento de novos fármacos envolve altos custos e não desperta interesse na indústria farmacêutica devido ao baixo retorno financeiro, por se tratar de doença parasitária, claramente negligenciada, e tida como doença de países pobres

Búsqueda de nuevos fármacos antichagásicos inhibidores de la Tripanotión sintetasa

Objetivo General - Identificar, mediante búsqueda racional asistida por computadora, nuevos compuestos químicos capaces de inhibir/modular la actividad de la enzima Tripanotión Sintetasa; los cuales puedan ser candidatos para utilizarse en la farmacoterapia de enfermedades originadas por tripanosomátidos. Objetivos Específicos - Compilar, a partir de literatura, un set de datos de compuestos con actividad reportada frente a la enzima Tripanotión Sintetasa. - Desarrollar y validar modelos computacionales basados en el ligando capaces de identificar compuestos químicos, tipo-fármaco. - Aplicar los modelos generados en campañas del tamizado virtual de diversas bibliotecas químicas. En particular, la identificación de drogas aprobadas por diferentes agencias regulatorias, permitiendo detectar la actividad de interés en fármacos ya utilizados en clínica para otras indicaciones terapéuticas (estrategia conocida como knowledge-based drug repurposing, es decir, búsqueda de segundos usos médicos basada en el conocimiento). - Adquirir los candidatos seleccionados a partir de la metodología in silico. - Evaluar experimentalmente, en ensayos in vitro, los compuestos adquiridos. Hipótesis de trabajo Mediante modelado in silico basado en el ligando se podrían identificar nuevos compuestos con actividad tripanocida, inhibidores de la enzima Tripanotión Sintetasa, entre los cuales existen posibles candidatos a fármacos, es decir, compuestos con las características farmacocinéticas/farmacodinámicas adecuadas para convertirse en potenciales agentes para el tratamiento de la enfermedad de Chagas.Facultad de Ciencias Exacta