RESUMO
Human leishmaniasis is a neglected tropical disease which affects nearly 1.5 million people every year, with Mexico being an important endemic region. One of the major defense mechanisms of these parasites is based in the polyamine metabolic pathway, as it provides the necessary compounds for its survival. Among the enzymes in this route, trypanothione reductase (TryR), an oxidoreductase enzyme, is crucial for the Leishmania genus' survival against oxidative stress. Thus, it poses as an attractive drug target, yet due to the size and features of its catalytic pocket, modeling techniques such as molecular docking focusing on that region is not convenient. Herein, we present a computational study using several structure-based approaches to assess the druggability of TryR from L. mexicana, the predominant Leishmania species in Mexico, beyond its catalytic site. Using this consensus methodology, three relevant pockets were found, of which the one we call σ-site promises to be the most favorable one. These findings may help the design of new drugs of trypanothione-related diseases.
Assuntos
Antiprotozoários , Leishmania , Leishmaniose , Humanos , Simulação de Acoplamento Molecular , Leishmania/metabolismo , NADH NADPH Oxirredutases/metabolismo , Leishmaniose/parasitologia , Antiprotozoários/uso terapêuticoRESUMO
The majority of OX40L is found on professional antigen-presenting cells (APC), the potency of OX40L to enhance the immunogenicity of potential vaccines against leishmania is not yet fully investigated. There is no report of administration of OX40L on cutaneous leishmaniasis either in therapy or prophylactic immunisation and the present study for the first time reports the effect of OX40L on L. mexicana infection. In this study, B9B8E2 cells were transfected with the murine OX40L and IgG1 plasmids, were used to produce the mOX40-mIgG1 (MM1). The therapeutic effects of MM1(mOX40L-mIgG1) was tested in a challenge experiment using L. mexicana infected BALB/c mice. Mice received two doses of MM1, on day 3 and 7 after the infection. Mice receiving MM1 generated an inflammatory reaction a few days after the injection of the OX40L, which was gradually dampened and finally disappeared 3 weeks later. There was a significant delay in the growth of developing lesions in mice receiving OX40L compared to controls injected with PBS and the size of lesions in the group receiving MM1 was significantly smaller than that of injected with either PBS. 40% of mice given MM1 remained lesion free for two months, when experiments were terminated. The results clearly indicate the high therapeutic effect of mOX40L-mIgG1 fusion protein in L. mexicana infection. The effect of OX40L on the enhancement of immunisation, needs to be further investigated for developing new vaccine strategies.
Assuntos
Leishmania , Leishmaniose Cutânea , Animais , Camundongos , Imunoglobulina G , Camundongos Endogâmicos BALB C , Leishmaniose Cutânea/prevenção & controle , Leishmaniose Cutânea/veterináriaRESUMO
Leishmania is the unicellular parasite transmitted by phlebotomine sand fly bite. It exists in two different forms; extracellular promastigotes, occurring in the gut of sand flies, and intracellular, round-shaped amastigotes residing mainly in vertebrate macrophages. As amastigotes originating from infected animals are often present in insufficient quality and quantity, two alternative types of amastigotes were introduced for laboratory experiments: axenic amastigotes and amastigotes from macrophages infected in vitro. Nevertheless, there is very little information about the degree of similarity/difference among these three types of amastigotes on proteomic level, whose comparison is crucial for assessing the suitability of using alternative types of amastigotes in experiments. In this study, L. mexicana amastigotes obtained from lesion of infected BALB/c mice were proteomically compared with alternatively cultivated amastigotes (axenic and macrophage-derived ones). Amastigotes of all three types were isolated, individually treated and analysed by LC-MS/MS proteomic analysis with quantification using TMT10-plex isobaric labeling. Significant differences were observed in the abundance of metabolic enzymes, virulence factors and proteins involved in translation and condensation of DNA. The most pronounced differences were observed between axenic amastigotes and lesion-derived amastigotes, macrophage-derived amastigotes were mostly intermediate between axenic and lesion-derived ones.
Assuntos
Leishmania mexicana , Camundongos , Animais , Leishmania mexicana/metabolismo , Proteoma/metabolismo , Proteômica , Cromatografia Líquida , Espectrometria de Massas em Tandem , Camundongos Endogâmicos BALB CRESUMO
We evaluated the leishmanicidal activity of commercially available 5α-cholest-7-en-3ß-ol [5α-chol], (+)-4-cholesten-3-one [(+)-4-chol] and the equimolar mixture of the two of them in promastigotes and amastigotes of two different strains of Leishmania mexicana (LCL) and (DCL). The leishmanicidal effectiveness of these sterols was determined by promastigote growth-kinetic experiments and promastigote viability using the propidium iodide staining procedure. The proliferation test was performed using the CFSE (5-Carboxyfluorescein N-succinimidyl ester) staining of parasites at different time points. To determine the leishmanicidal effectiveness of these sterols in amastigotes, we evaluated parasite killing inside of macrophages at different time points. The trypan blue exclusion test was used to determine cytotoxicity of sterols in uninfected macrophages. We included in all experiments a control group of parasites treated with 2% DMSO (Dimethyl Sulfoxide) and another one treated with the reference drug sodium stibogluconate (Sb). Our results showed that the equimolar mixture at 2000 times lower concentration presented similar leishmanicidal activity as Sb. This mixture was similarly effective at 100 times lower concentration than individual sterols tested separately indicating the existence of a synergistic effect against LCL and DCL parasites. The therapeutic index of the equimolar mixture was 10,000-16,000 times higher than the one recorded by Sb and was not cytotoxic to macrophages. Therefore, the equimolar mixture of 5α-Chol and (+)-4-chol may represent a potential alternative for the treatment of cutaneous leishmaniasis.
Assuntos
Leishmania mexicana , Leishmaniose Cutânea , Gluconato de Antimônio e Sódio/farmacologia , Colesterol , Humanos , Leishmaniose Cutânea/tratamento farmacológico , Esteróis/farmacologiaRESUMO
In previous studies, carried out in humans, we showed that females are resistant to Leishmania mexicana infection. We also showed that 17ß-estradiol (E2) induces killing of parasites inside of murine macrophages. In this work, we compared, for the first time, L mexicana survival inside of male (male BMDM) and female (female BMDM) bone marrow-derived macrophages (BMDM) treated in vitro with E2 or dihydrotestosterone (DHT). We also compared their levels of nitric oxide (NO), interleukin (IL)-6, IL-10, IL-12p70 and tumour necrosis factor (TNF-α). We found that female BMDM are a lot less susceptible to infection as compared with male BMDM. 17ß-estradiol induced killing of most parasites inside of female BMDM. Dihydrotestosterone, on the other hand, induced some parasite killing inside of some infected male BMDM. Interleukin-6 levels were higher in female BMDM treated with either hormone. Neither TNF-α nor IL-10 levels showed significant differences compared with sham controls. Interestingly IL-12p70 was more abundantly produced by sham female BMDM as compared with sham male BMDM. Only female BMDM treated with E2 trigger a robust IL-12p70 production, but it was significantly reduced in male BMDM. This suggests IL-12p70 is an important factor in female-macrophage resistance to L mexicana parasites.
Assuntos
Estradiol/metabolismo , Interleucina-12/imunologia , Leishmania mexicana/fisiologia , Leishmaniose Cutânea/imunologia , Macrófagos/imunologia , Animais , Citocinas/análise , Di-Hidrotestosterona/administração & dosagem , Estradiol/administração & dosagem , Feminino , Humanos , Leishmaniose Cutânea/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos CBA , Óxido Nítrico/análise , Fatores SexuaisRESUMO
To identify new agents for the treatment of American cutaneous leishmaniasis, a series of eight 1,4-bis(substituted benzalhydrazino)phthalazines was evaluated against Leishmania braziliensis and Leishmania mexicana parasites. These compounds represent a disubstituted version of the 1-chloro-4-(monoaryl/heteroarylhydranizyl)phthalazine that exhibited a significant response against L. braziliensis according to our previous findings. Two disubstituted phthalazines 3b and 3f were identified as potential antileishmanial agents against L. braziliensis parasites, exhibiting a submicromolar IC50 response of 2.37 and 7.90 µM on the promastigote form, and of 1.82 and 4.56 µM against intracellular amastigotes, respectively. In particular, compound 3b showed interesting responses against amastigote isolates from reference, glucantime-resistant and clinical human strains, which were by far superior to the biological response found for the glucantime drug. With regard to the toxicity results, both 3b and 3f exhibited moderate LD50 values against murine macrophages (BMDM), with good selectivity indexes on promastigotes and intracellular amastigotes of L. braziliensis. A comparison of biological response was established between the monosubstituted and disubstituted versions of these benzalhydrazino-phthalazines. Easy synthetic procedure and significant response against amastigote strains including against resistant lines made compound 3b a potential candidate for further pharmacokinetic and in vivo experiments as antileishmanial agent, and as a platform for further structural optimization. Mechanism-of-action studies and molecular docking simulations discarded to inhibition of superoxide dismutase as possible mode of action.
Assuntos
Antiprotozoários/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Leishmania mexicana/efeitos dos fármacos , Leishmania/efeitos dos fármacos , Ftalazinas/farmacologia , Animais , Antiprotozoários/química , Antiprotozoários/toxicidade , Células Cultivadas , Leishmania braziliensis/crescimento & desenvolvimento , Leishmania braziliensis/metabolismo , Leishmania mexicana/crescimento & desenvolvimento , Leishmania mexicana/metabolismo , Dose Letal Mediana , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Simulação de Acoplamento Molecular , Estrutura Molecular , Ftalazinas/química , Ftalazinas/toxicidade , Relação Estrutura-Atividade , Superóxido Dismutase/metabolismoRESUMO
Trifluoromethyl-substituted quinolones and their analogues have emerged as an interesting platform in the last 6 years to design antiparasite agents. Many of their derivatives have been demonstrated to display excellent efficacy against flagellate parasites such as Plasmodium spp. In order to identify new analogues of trifluoromethyl-substituted quinolones to treat the American cutaneous leishmaniasis, we evaluated the antiproliferative activity of a series of 2-(trifluoromethyl)benzo[b]-[1,8]naphthyridin-4(1H)-ones on the Leishmania braziliensis and Leishmania mexicana parasites. The mentioned derivatives have never been evaluated against any parasite strain. In general, an in vitro evaluation on L.(L)mexicana and L.(V)braziliensis showed that L.(L)mexicana was more sensitive to the action of the compounds than L.(V)braziliensis, either in the promastigote or in the amastigote form. Five compounds exhibited moderate efficacy against L.(L)mexicana promastigotes, with IC50 values ranging from 9.65 to 14.76 µM. From the mentioned molecules, three compounds, 1e, 1f, and 1h, showed a discrete response against axenic and intracellular amastigotes, with LD50 values between 19 and 24 µM. Moreover, an in vitro evaluation was performed on an antimony-resistant amastigote strain and a human isolate amastigote strain. These three compounds showed discrete toxicity on peritoneal macrophages; however, their relatively good antiamastigote response compared to the drug glucantime promoted our trifluoromethyl-substituted benzo[b][1,8]naphthyridin-4(1H)-ones as a potential platform to design potent antileishmanial agents.
RESUMO
We evaluated, for the first time, the leishmanicidal potential of decanethiol functionalized silver nanoparticles (AgNps-SCH) on promastigotes and amastigotes of different strains and species of Leishmania: L. mexicana and L. major isolated from different patients suffering from localized cutaneous leishmaniasis (CL) and L. mexicana isolated from a patient suffering from diffuse cutaneous leishmaniasis (DCL). We recorded the kinetics of promastigote growth by daily parasite counting for 5 days, promastigote mobility, parasite reproduction by CFSE staining's protocol and promastigote killing using the propidium iodide assay. We also recorded IC50's of promastigotes and amastigotes, therapeutic index, and cytotoxicity by co-culturing macrophages with AgNps-SCH or sodium stibogluconate (Sb) used as reference drug. We used Sb as a reference drug since it is used as the first line treatment for all different types of leishmaniasis. At concentrations 10,000 times lower than those used with Sb, AgNps-SCH had a remarkable leishmanicidal effect in all tested strains of parasites and there was no toxicity to J774A.1 macrophages since > 85% were viable at the concentrations used. Therapeutic index was about 20,000 fold greater than the corresponding one for Sb treated cells. AgNps-SCH inhibited > 80% promastigote proliferation in all tested parasites. These results demonstrate there is a high leishmanicidal potential of AgNps-SCH at concentrations of 0.04 µM. Although more studies are needed, including in vivo testing of AgNps-SCH against different types of leishmaniasis, they can be considered a potential new treatment alternative.
Assuntos
Antiprotozoários/farmacologia , Leishmania/efeitos dos fármacos , Nanopartículas Metálicas/química , Prata/farmacologia , Animais , Gluconato de Antimônio e Sódio/farmacologia , Antiprotozoários/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Humanos , Concentração Inibidora 50 , Cinética , Leishmania/crescimento & desenvolvimento , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/parasitologia , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Prata/administração & dosagemRESUMO
Current chemotherapeutic agents for leishmaniasis have several disadvantages interfering with the effective treatment and therefore more and better antileishmanial drugs are needed. Discovery of candidates for leishmaniasis treatment requires not only accurate and precise methodologies but also well-known biological system to measure infectivity of parasites and antileishmanial activity of the new compounds. Significant variation in the in vitro and in vivo infectivity and sensitivity to established and experimental drugs in Leishmania strains are reported. This work reports the in vitro biological behavior and antileishmanial drugs sensitivity of different green fluorescent protein transfectant Leishmanias strains. The in vitro growth kinetic and infectivity to U937 cells vary slightly in the Leishmania transfectant strains in comparison with their correspondant wild-type. However, the insertion of the pIR3(-)-eGFP may affect the sensitivity of the parasites to meglumine antimoniate (MA) and miltefosine but not to amphotericin B (AMB) and pentamidine isethionate. In consequence, AMB or pentamidine isethionate but not MA or miltefosine should be used as antileishmanial control drugs during in vitro assays of antileishmanial activity. Furthermore, is recommended to test compounds against more than one Leishmania strain in order to verify that the antileihmanial activity of these compound is similar among species.
Assuntos
Antiprotozoários/farmacologia , Proteínas de Fluorescência Verde/genética , Leishmania/efeitos dos fármacos , Leishmaniose/tratamento farmacológico , Testes de Sensibilidade Parasitária , Especificidade da Espécie , TransfecçãoRESUMO
Peromyscus yucatanicus, the main reservoir of Leishmania (Leishmania) mexicana in the Yucatan peninsula of Mexico, reproduces clinical and histological pictures of LCL in human as well as subclinical infection. Thus, we used this rodent as a novel experimental model. In this work, we analyzed cytokine mRNA expression in P. yucatanicus infected with L. (L.) mexicana. Animals were inoculated with either 2.5×10(6) or 1×10(2) promastigotes and cytokine expressions were analyzed by real-time RT-PCR in skin at 4 and 12weeks post-infection (wpi). Independently of the parasite inoculum none of the infected rodents had clinical signs of LCL at 4wpi and all expressed high IFN-γ mRNA. All P. yucatanicus inoculated with 2.5×10(6) promastigotes developed signs of LCL at 12wpi while the mice inoculated with 1×10(2) remained subclinical. At that time, both IFN-γ and IL-10 were expressed in P. yucatanicus with clinical and subclinical infections. Expressions of TNF-α and IL-4 were significantly higher in clinical animals (2.5×10(6)) compared with subclinical ones (1×10(2)). High TGF-ß expression was observed in P. yucatanicus with clinical signs when compared with healthy animals. Results suggested that the clinical course of L. (L.) mexicana infection in P. yucatanicus was associated with a specific local pattern of cytokine production at 12wpi.
Assuntos
Citocinas/biossíntese , Regulação da Expressão Gênica , Leishmania mexicana/metabolismo , Leishmaniose Cutânea/metabolismo , Peromyscus/metabolismo , Animais , Peromyscus/parasitologia , RNA Mensageiro/biossínteseRESUMO
Ox40 ligand (Ox40L)-Ox40 pathway has been shown to enhance Th2 responses and play a role in pathogenesis of cutaneous leishmaniasis (CL) caused by Leishmania major. Using Ox40l(-/-) BALB/c mice we analyzed the role of this pathway in determining the outcome to CL caused by L. mexicana and compared to L. major. Contrary to our expectations, Ox40l(-/-) mice were highly susceptible to both L. major (LV39) and L. mexicana (M379) and developed large non-healing lesions containing parasites comparable to Ox40l(+/+) BALB/c mice. Interestingly, upon in vitro stimulation with Leishmania antigen (LmAg), the lymph node cells from L. major infected Ox40l(-/-) mice produced significantly less IL-4 and IL-10 compared to Ox40l(+/+) mice. L. mexicana infected Ox40l(-/-) and Ox40l(+/+) mice did not show any difference in the production of IL-4 and IL-10. No difference was noted in the amount of Th1 cytokines IFN-Ò¯ and IL-12 produced by Ox40l(-/-) and Ox40l(+/+) mice infected with either parasite. These results indicate that the Ox40L-Ox40 pathway promotes Th2 bias only in L. major infection but not L. mexicana infection and this pathway is not critical for susceptibility to CL.
Assuntos
Leishmania major , Leishmania mexicana , Leishmaniose Cutânea/imunologia , Ligante OX40/metabolismo , Receptores OX40/metabolismo , Células Th2/metabolismo , Animais , Anticorpos Antiprotozoários/sangue , Citocinas/sangue , Feminino , Leishmania major/imunologia , Leishmania major/patogenicidade , Leishmania mexicana/imunologia , Leishmania mexicana/patogenicidade , Leishmaniose Cutânea/parasitologia , Leishmaniose Cutânea/patologia , Camundongos , Camundongos Endogâmicos BALB C , Ligante OX40/imunologia , Receptores OX40/imunologia , Células Th2/imunologia , VirulênciaRESUMO
Peromyscus yucatanicus (Rodentia: Cricetidae) is a primary reservoir of Leishmania (Leishmania) mexicana (Kinetoplastida: Trypanosomatidae). Nitric oxide (NO) generally plays a crucial role in the containment and elimination of Leishmania. The aim of this study was to determine the amount of NO produced by P. yucatanicus infected with L. (L.) mexicana. Subclinical and clinical infections were established in P. yucatanicus through inoculation with 1 x 10 2 and 2.5 x 10 6 promastigotes, respectively. Peritoneal macrophages were cultured alone or co-cultured with lymphocytes with or without soluble Leishmania antigen. The level of NO production was determined using the Griess reaction. The amount of NO produced was significantly higher (p ≤ 0.0001) in co-cultured macrophages and lymphocytes than in macrophages cultured alone. No differences in NO production were found between P. yucatanicus with subclinical L. (L.) mexicana infections and animals with clinical infections. These results support the hypothesis that the immunological mechanisms of NO production in P. yucatanicus are similar to those described in mouse models of leishmaniasis and, despite NO production, P. yucatanicus is unable to clear the parasite infection.
Assuntos
Animais , Leishmania mexicana/imunologia , Leishmaniose Cutânea/imunologia , Macrófagos Peritoneais/parasitologia , Óxido Nítrico/biossíntese , Peromyscus/metabolismo , Modelos Animais de Doenças , Macrófagos Peritoneais/imunologia , Peromyscus/parasitologiaRESUMO
Antecedentes. En el modelo murino más estudiado, producido por L, major, se observa correlación entre cepas resistentes (C57BL6) y susceptibles (BALB/c), con respuestas inmunes Th1 o Th2, respectivamente. Esta dicotomía no se observa en modelos desarrollados con otras especies de Leishmania (L). Por ello es importante avanzar en el estudio de modelos experimentales con especies predominantes de nuestra zona. El objetivo fue reproducir la enfermedad en diferentes cepas murinas luego de la infección por L. amazonensis. Métodos. Para conocer el efecto de la variable cepa de ratones sobre la susceptibilidad a la infección por L. amazonensis, se aplicó un inóculo constante del parásito a las cepas en estudio. Se evaluó la respuesta de las cepas C57BL/6, BALB/c y Swiss, por medición de lesiones, estimación de carga parasitaria e histopatología. Por ELISA se determinaron anticuerpos y citoquinas en suero. Test estadístico: análisis de la varianza (ANOVA). Resultados. BALB/c demostró máxima susceptibilidad a la infección; Swiss presentó un fenotipo intermedio, y C57BL/6 fue la menos susceptible. Se obtuvieron modelos murinos que reprodujeron distintas formas clínicas comparables a la enfermedad humana. Conclusiones. Los resultados servirán para extrapolar a la patología humana las conclusiones de posteriores ensayos terapéuticos y profilácticos sobre animales experimentales.
Background.Most studies have been based onL. majormouse mo-dels, where Th1 and Th2 immune responses are associated with resistant(C57BL/6) and susceptible (BALB/c) strains, respectively. This dichotomyis not generally observed in models developed with otherLeishmania (L.)species. Therefore, the study of mouse models involving species respon-sible for human infections in our region represents an important challen-ge. The aim was to induce the disease in diff erent mouse strains after theinfection withL. amazonensis.Methods.To study the eff ect of mice strain variable over susceptibilityforL. amazonensisinfection, a constant parasite inoculum was appliedto the studied mice strains. Response to infection was characterized inC57BL/6, BALB/c, and Swiss strains by lesion measurement, parasitic loadestimate and histological analysis. Serum presence of antibodies andcytokines was determinated by ELISA. Statistical analysis: ANOVA test.Results.BALB/c showed the maximum level of susceptibility towardsthe infection. Swiss demonstrated an intermediate phenotype andC57BL/6 was the most resistant strain. We could obtain murine modelsrefl ecting diff erent clinical forms present in human disease.Conclusions.These results will be useful to extrapolate to human pa-thology future conclusions about therapeutic and prophylaxis analysison experimental models (Dermatol Argent 2009;15(5):334-339)