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Association of efflux pump inihibitors with antileishmanial drugs as an alternative treatment for leishmaniasis
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A leishmaniose é uma das doenças mais negligenciadas em todo o Mundo, de acordo com a OMS, sendo todos os anos registados 300 000 novos casos. A doença afecta, sobretudo, indivíduos de países em vias de desenvolvimento, onde o acesso ao diagnóstico e ao tratamento se torna extremamente complicado. Para além disso, a quimioterapia disponível apresenta uma eficácia progressivamente menor devido ao aparecimento de estirpes resistentes. Com tudo isto, torna-se imperativo o desenvolvimento de novos compostos antileishmania e de novas estratégias para diminuir o impacto da doença. As proteínas pertencentes à família ATP-binding cassette (ABC) são transportadores que se encontram presentes numa grande variedade de células (desde procariotas a eucariotas) e que são responsáveis pelo efluxo de moléculas. Muitas vezes, estes transportadores originam fenótipos resistentes, como é o caso do fenótipo multidrug resistant (MDR). Uma forma de ultrapassar esta resistência é recorrendo ao uso de inibidores destas bombas de efluxo. O principal objectivo deste trabalho é determinar a acção de bombas de efluxo num contexto em que macrófagos de uma linha celular (P388D1) são infectados com promastigotas mais resistentes pertences a diferentes espécies de Leishmania (Leishmania infantum, Leishmania amazonensis, Leishmania shawi e Leishmania guyanensis) e são expostos simultaneamente a fármacos/compostos experimentais antileishmania e inibidores das bombas de efluxo. No presente trabalho, o primeiro passo foi obter estirpes susceptíveis ao Glucantime (GLUC), à Miltefosina (MILT), ao ácido ursólico (URS), à chalcona-8 (CH8) e à quercetine (QC). Para as estirpes que se conseguiram obter, foi determinado o valor de IC50 para os compostos experimentais URS, CH8 e QC. Por último, num contexto em que macrófagos foram infectados com diferentes estirpes mais resistentes, foi determinado o efeito na taxa de infecção relativa de um tratamento constituído por um composto antileishmania e por um inibidor das bombas de efluxo (EPI), como o verapamil (VER), o ortovanadato de sódio (ORT) e o Phe-Arg β-naftilamida (PaβN). Todos os tratamentos foram capazes de reduzir a taxa de infecção relativa de macrófagos infectados com as estirpes susceptíveis de Leishmania infantum, à excepção do tratamento com CH8 e VER feito à estirpe INF CH8. Para as diferentes estirpes de Leishmania amazonensis, todos os tratamentos apresentaram resultados positivos, à excepção daqueles que incluíam ORT, que parece ser inofensivo para esta espécie. No extremo oposto, encontram-se as estirpes de Leishmania shawi e Leishmania guyanensis, em que nenhum dos tratamentos reduziu a taxa de infecção. Os inibidores das bombas de efluxo (EPI) conseguem reduzir a actividade das bombas de efluxo e aumentar a eficácia dos fármacos antileishmania, e, por causa disso, o seu uso pode constituir um bom tratamento alternativo para a leishmaniose.
Leishmaniasis is one of the most neglected diseases in the World, according to the WHO, with new registered 300 000 cases every year. This disease affects mainly individuals from low income countries, where the access to diagnosis and treatment is very difficult. Besides this, the available chemotherapy is losing efficacy due to the emergence of resistant strains. So, there is a need for the development of new antileishmanial compounds and new strategies to refrain the impact of the disease. The proteins belonging to the ATP-binding cassette (ABC) family are transporters present in a wide variety of cells (from prokaryotes to eukaryotes) involved in the efflux of molecules. In many cases, these transporters become responsible for multidrug resistant (MDR) phenotypes and other resistance events in cells. One of the strategy to overcome this resistance is to use efflux pump inhibitors (EPI). The general goal of the present work is determine the action of efflux pumps in a context where macrophages from a cellular line (P388D1) get infected with more resistant Leishmania promastigotes from several species (Leishmania infantum, Leishmania amazonensis, Leishmania shawi and Leishmania guyanensis) and are exposed simultaneously to antileishmanial drugs/experimental compounds and efflux pump inhibitors. In this work, the first step was to differentiate different strains susceptible to Glucantime (GLUC), Miltefosine (MILT), ursolic acid (URS), chalcone-8 (CH8) and quercetine (QC). For the resistant strains obtained, the IC50 of the experimental compounds URS, CH8 and QC were then calculated. At last, in a context of macrophages infected with the different more resistant strains, it was evaluated the effect in their relative infection rate of a treatment consisting in experimental compounds combined with EPI, such as verapamil (VER), sodium orthovanadate (ORT) and Phe-Arg β-naphthylamide (PAβN). All the treatments could significantly reduce the relative infection rate of macrophages infected with the susceptible strains of Leishmania infantum, with the exception of the treatment with CH8 and VER in INF CH8 strain. For the several strains of Leishmania amazonensis, all treatments reduced the relative infection rate, with the exception for the treatments containing ORT, which seems to be harmless to this species. On the opposite side are the strains of Leishmania shawi and Leishmania guyanensis, where none of the treatments was able to reduce the relative infection rate of the macrophages. The EPI can effectively decrease the activity of efflux pumps activity and increase the efficacy of antileishmanial drugs, and because of this, its use can be a possible alternative treatment for leishmaniasis.
Leishmaniasis is one of the most neglected diseases in the World, according to the WHO, with new registered 300 000 cases every year. This disease affects mainly individuals from low income countries, where the access to diagnosis and treatment is very difficult. Besides this, the available chemotherapy is losing efficacy due to the emergence of resistant strains. So, there is a need for the development of new antileishmanial compounds and new strategies to refrain the impact of the disease. The proteins belonging to the ATP-binding cassette (ABC) family are transporters present in a wide variety of cells (from prokaryotes to eukaryotes) involved in the efflux of molecules. In many cases, these transporters become responsible for multidrug resistant (MDR) phenotypes and other resistance events in cells. One of the strategy to overcome this resistance is to use efflux pump inhibitors (EPI). The general goal of the present work is determine the action of efflux pumps in a context where macrophages from a cellular line (P388D1) get infected with more resistant Leishmania promastigotes from several species (Leishmania infantum, Leishmania amazonensis, Leishmania shawi and Leishmania guyanensis) and are exposed simultaneously to antileishmanial drugs/experimental compounds and efflux pump inhibitors. In this work, the first step was to differentiate different strains susceptible to Glucantime (GLUC), Miltefosine (MILT), ursolic acid (URS), chalcone-8 (CH8) and quercetine (QC). For the resistant strains obtained, the IC50 of the experimental compounds URS, CH8 and QC were then calculated. At last, in a context of macrophages infected with the different more resistant strains, it was evaluated the effect in their relative infection rate of a treatment consisting in experimental compounds combined with EPI, such as verapamil (VER), sodium orthovanadate (ORT) and Phe-Arg β-naphthylamide (PAβN). All the treatments could significantly reduce the relative infection rate of macrophages infected with the susceptible strains of Leishmania infantum, with the exception of the treatment with CH8 and VER in INF CH8 strain. For the several strains of Leishmania amazonensis, all treatments reduced the relative infection rate, with the exception for the treatments containing ORT, which seems to be harmless to this species. On the opposite side are the strains of Leishmania shawi and Leishmania guyanensis, where none of the treatments was able to reduce the relative infection rate of the macrophages. The EPI can effectively decrease the activity of efflux pumps activity and increase the efficacy of antileishmanial drugs, and because of this, its use can be a possible alternative treatment for leishmaniasis.
Descrição
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Saúde pública Parasitologia médica Leishmaniose Compostos antileishmania Parasitas resistentes Bombas de efluxo Inibidores
Contexto Educativo
Citação
Editora
Instituto de Higiene e Medicina Tropical