RESUMO
BACKGROUND: The mechanisms that mediate immune protection in individuals with subclinical (SC) or asymptomatic infection with L. braziliensis are largely unknown. Neutrophils (PMNs) have been implicated in progressive symptomatic cutaneous leishmaniasis (CL), but their potential participation in maintenance of subclinical infection is unexplored. The aim of this study was to compare the phenotypic and functional profiles of PMNs in individuals with SC infection versus patients with symptomatic CL due to L. braziliensis. METHODS: Subjects were recruited in the endemic region of Corte de Pedra, Bahia, Brazil. Surface markers to define activation status were characterized by flow cytometry. Functional responses of PMNs including phagocytic capacity, production of oxidative species, and oxidative killing of intracellular parasites were studied in vitro. RESULTS: PMNs from individuals with SC infection displayed a more activated phenotype and greater ability to control the infection than PMNs from patients with CL. In contrast, PMNs from patients with CL exhibited higher expression of HLA-DR and higher production of oxidative species than PMNs from subjects with SC infection. CONCLUSION: PMNs from individuals with SC infection can control the infection more efficiently than PMNs from patients with CL, despite the lower production of oxidants. Our observations suggest that L. braziliensis may evade microbicidal mechanisms of PMNs from patients with CL, contributing to parasite dissemination and the establishment of disease.
RESUMO
Disseminated leishmaniasis is an emerging clinical form of Leishmania braziliensis infection. Evidence shows that co-infection by L. braziliensis and intestinal helminths does not affect clinical manifestations or response to therapy in cutaneous leishmaniasis patients. We evaluated whether co-infection was associated with those aspects in disseminated leishmaniasis patients in Brazil.
Assuntos
Coinfecção , Helmintíase , Enteropatias Parasitárias , Humanos , Brasil/epidemiologia , Enteropatias Parasitárias/epidemiologia , Enteropatias Parasitárias/complicações , Enteropatias Parasitárias/parasitologia , Masculino , Feminino , Adulto , Helmintíase/complicações , Helmintíase/epidemiologia , Helmintíase/parasitologia , Pessoa de Meia-Idade , Leishmania braziliensis/isolamento & purificação , Adulto Jovem , Adolescente , Animais , IdosoRESUMO
Disseminated leishmaniasis (DL) is an emergent severe disease manifesting with multiple lesions. To determine the relationship between immune response and clinical and therapeutic outcomes, we studied 101 DL and 101 cutaneous leishmaniasis (CL) cases and determined cytokines and chemokines in supernatants of mononuclear cells stimulated with leishmania antigen. Patients were treated with meglumine antimoniate (20 mg/kg) for 20 days (CL) or 30 days (DL); 19 DL patients were instead treated with amphotericin B, miltefosine, or miltefosine and meglumine antimoniate. High levels of chemokine ligand 9 were associated with more severe DL. The cure rate for meglumine antimoniate was low for both DL (44%) and CL (60%), but healing time was longer in DL (p = 0.003). The lowest cure rate (22%) was found in DL patients with >100 lesions. However, meglumine antimoniate/miltefosine treatment cured all DL patients who received it; therefore, that combination should be considered as first choice therapy.
Assuntos
Leishmania braziliensis , Leishmania , Leishmaniose Cutânea , Fosforilcolina/análogos & derivados , Humanos , Antimoniato de Meglumina/uso terapêutico , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/tratamento farmacológicoRESUMO
Leishmania braziliensis is a pathogenic protozoan parasite that causes American Tegumentary Leishmaniasis (ATL), an important tropical neglected disease. ENTPDases are nucleotidases that hydrolyze intracellular and/or extracellular nucleotides. ENTPDases are known as regulators of purinergic signalling induced by extracellular nucleotides. Leishmania species have two isoforms of ENTPDase, and, particularly, ENTPDase2 seems to be involved in infectivity and virulence. In this study, we conducted the heterologous expression and biochemical characterization of the recombinant ENTPDase2 of L. braziliensis (rLbNTPDase2). Our results show that this enzyme is a canonical ENTPDase with apyrase activity, capable of hydrolysing triphosphate and diphosphate nucleotides, and it is dependent on divalent cations (calcium or magnesium). Substrate specificity was characterized as UDP>GDP>ADP>GTP>ATP=UTP. The enzyme showed optimal activity at a neutral to basic pH and was partially inhibited by suramin and DIDS. Furthermore, the low apparent Km for ADP suggests that the enzyme may play a role in adenosine-mediated signalling. The biochemical characterization of this enzyme can open new avenues for using LbNTPDase2 as a drug target.
RESUMO
In this serum panel-based study, we evaluated the accuracy of serological tests originally developed for visceral leishmaniasis (VL), for diagnosis of mucosal leishmaniasis (ML). A total of five tests were evaluated, four of which are registered at the National Agency of Sanitary Surveillance (Agência Nacional de Vigilância Sanitária-ANVISA) (RIDASCREEN® Leishmania Ab from R-Biopharm AG., Leishmania ELISA IgG + IgM from Vircell S.L., IFI Leishmaniose Humana-BioManguinhos, and IT-LEISH® from Bio-Rad Laboratories, Inc.), and the other a direct agglutination test (DAT-LPC) prototype kit developed at Fiocruz. The panel was composed of 40 serum samples from patients with confirmed ML and 20 from patients with mucosal involvement and negative parasitological/molecular tests for leishmaniasis and confirmation of another etiology. All cases were treated from 2009 to 2016 in a referral center for leishmaniasis in Belo Horizonte, Minas Gerais, Brazil (Instituto René Rachou, Fiocruz). Diagnostic accuracy, based on the cut-off point for VL diagnosis, was 86.2% with RIDASCREEN® Leishmania Ab, 73.3% with Leishmania ELISA IgG + IgM, and 66.7% with IFI Leishmaniose Humana, while IT-LEISH® and DAT-LPC had the lowest accuracy (38.3%), despite high specificity (100% and 95%, respectively). New cut-off points defined with sera from ML patients improved accuracy from 86.2 to 89% (p = 0.64) and 73.3 to 88% (p = 0.04) for RIDASCREEN® Leishmania Ab and Leishmania ELISA IgG + IgM, respectively. Moreover, these tests presented greater sensitivity and immunoreactivity in patients with moderate/severe clinical ML forms. The data of this study suggest that ELISA assays can contribute to laboratory diagnosis, especially for patients with moderate or severe mucosal involvement.
Assuntos
Leishmania , Leishmaniose Visceral , Humanos , Sensibilidade e Especificidade , Testes Sorológicos , Testes de Aglutinação , Leishmaniose Visceral/diagnóstico , Ensaio de Imunoadsorção Enzimática , Imunoglobulina G , Imunoglobulina M , Anticorpos Antiprotozoários , Antígenos de ProtozoáriosRESUMO
BACKGROUND: We have previously shown that seropositivity to rLinB-13, a salivary protein from Lutzomyia intermedia, predicted sand fly exposure and was associated with increased risk of developing cutaneous leishmaniasis (CL). METHODS: Here, we investigated the cellular immune response to saliva from Lu. intermedia, using rLinB-13 as a surrogate antigen in naturally exposed individuals presenting positive serology to LinB-13. We also investigated the response to rLinB-13 in leishmaniasis patients, displaying active ulcers and positive PCR for Leishmania braziliensis. RESULTS: Peripheral blood mononuclear cells (PBMCs) stimulated in vitro with rLinB-13 secreted elevated levels of interleukin-10 (IL-10), IL-4, IL-1ß, IL-1α, IL-6, and chemokines (CCL3, CCL4, CCL5, and CXCL5). CL and disseminated leishmaniasis (DL) patients displayed a significantly higher immunoglobulin G (IgG) response to rLinB-13 compared with healthy subjects, and anti-rLinB-13 IgG was positively correlated with the number of lesions in DL patients. Positive serology to rLinB-13 was also associated with chemotherapy failure. PBMCs from DL patients stimulated with rLINB-13 secreted significantly higher levels of IL-10 and IL-1ß compared with CL individuals. CONCLUSIONS: In this study, we observed an association between humoral and cellular immune response to the sand fly salivary protein rLinB-13 and disease severity in tegumentary leishmaniasis. This study brings evidence that immunity to rLinB-13 influences disease outcome in L. braziliensis infection and results indicate that positive serology to rLinB-13 IgG can be used as a marker of DL, an emerging and severe form of disease caused by L. braziliensis.
Assuntos
Leishmania braziliensis , Leishmaniose Cutânea , Phlebotomus , Psychodidae , Animais , Interleucina-10/metabolismo , Leucócitos Mononucleares , Proteínas e Peptídeos Salivares , Imunidade Celular , Imunoglobulina G , Índice de Gravidade de DoençaRESUMO
Tegumentary leishmaniasis (TL) is a disease of high severity and incidence in Brazil, and Leishmania braziliensis is its main etiological agent. The inefficiency of control measures, such as high toxicity and costs of current treatments and the lack of effective immunoprophylactic strategies, makes the development of vaccines indispensable and imminent. In this light, the present work developed a gene encoding multiple T-cell (CD4+/CD8+) epitope, derived from conserved proteins found in Leishmania species and associated with TL, to generate a chimeric protein (rMEP/TL) and compose a vaccine formulation. For this, six T-cell epitopes were selected by immunoinformatics approaches from proteins present in the amastigote stage and associated with host-parasite interactions. The following formulations were then tested in an L. braziliensis murine infection model: rMEP/TL in saline or associated with MPLA-PHAD®. Our data revealed that, after immunization (three doses; 14-day intervals) and subsequent challenging, rMEP/TL and rMEP/TL + MPLA-vaccinated mice showed an increased production of key immunological biomarkers of protection, such as IgG2a, IgG2a/IgG1, NO, CD4+, and CD8+ T-cells with IFN-γ and TNF-α production, associated with a reduction in CD4+IL-10+ and CD8+IL-10+ T-cells. Vaccines also induced the development of central (CD44highCD62Lhigh) and effector (CD44highCD62Llow) memory of CD4+ and CD8+ T-cells. These findings, associated with the observation of lower rates of parasite burdens in the vaccinated groups, when compared to the control groups, suggest that immunization with rMEP/TL and, preferably, associated with an adjuvant, may be considered an effective tool to prevent TL. KEY POINTS: ⢠Rational design approaches for vaccine development. ⢠Central and effector memory of CD4+ and CD8+ T-cells. ⢠Vaccine comprised of rMEP/TL plus MPLA as an effective tool to prevent TL.
Assuntos
Vacinas contra Leishmaniose , Leishmaniose , Animais , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Epitopos de Linfócito T/genética , Imunoglobulina G , Interleucina-10/metabolismo , Leishmaniose/prevenção & controle , Vacinas contra Leishmaniose/genética , Camundongos , Camundongos Endogâmicos BALB CRESUMO
Leishmania (Viannia) braziliensis is the main species responsible for American tegumentary leishmaniasis in Brazil. Nevertheless, the use of this parasite species to study Leishmania infection in the murine model has been less conducted when compared with other Leishmania species. The control of murine infection with Leishmania has been associated with nitric oxide (NO) produced by inducible NO synthase (iNOS) from M1 macrophages, while arginase expressed by M2 macrophages is related to Leishmania proliferation. Here we use three different strains of L. (V.) braziliensis and one strain of L. (L.) major to study a 9-day infection of macrophages in vitro. Wild-type bone marrow-derived macrophages (BMDM) supported the proliferation of L. (L) major amastigotes from the 3rd day after infection, while all strains of L. (V.) braziliensis did not proliferate even inside IL-4-treated or iNOS knockout (KO) macrophages. The arginase activity was higher in iNOS KO than IL-4-treated macrophage showing that the absence of proliferation is independent of arginase. Importantly, L. (V.) braziliensis was able to cause uncontrolled disease in iNOS KO mice in vivo demonstrating that murine macrophages present at the site of infection have additional changes beyond inhibition of NO production or stimulation of arginase activity to support parasite proliferation.
Assuntos
Leishmania braziliensis , Leishmania , Leishmaniose Cutânea , Animais , Arginase/genética , Proliferação de Células , Interleucina-4 , Leishmaniose Cutânea/parasitologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Knockout , Óxido NítricoRESUMO
BACKGROUND: Leishmania skin test (LST) evaluates the delayed type hypersensitivity to Leishmania antigens (LA) and has been used for diagnosis of cutaneous leishmaniasis (CL). In CL patients LST is usually positive but a small percentage have negative LST. The aim of this study was to determine the clinical and immunologic features and response to antimony therapy in LST-negative CL patients. METHODS: We compare the clinical presentation, response to therapy, and immune response of CL patients with negative vs positive LST. RESULTS: The clinical presentation was similar in both groups but LST-negative patients had a lower cure rate. In the lesions, LST-negative patients displayed less inflammation and necrosis, and higher frequency of CD8+ T cells. Mononuclear cells from LST-negative patients had a poor T helper 1 cell (Th1) response but levels of interleukin-1ß (IL-1ß), IL-6, IL-17, granzyme B, and metalloproteinase-9 (MMP-9) were similar to the LST-positive group upon stimulation with LA. Leishmania internalization and killing by macrophages were similar in both groups. Cure of disease was associated with restoration of Th1 response. CONCLUSIONS: In LST-negative patients, impaired Th1 response is associated with therapeutic failure. Increased frequency of CD8+ T cells and high production of inflammatory cytokines, granzyme B, and MMP-9 contributes to immunopathology.
Assuntos
Leishmania braziliensis/imunologia , Leishmaniose Cutânea/parasitologia , Células Th1/imunologia , Adolescente , Adulto , Idoso , Antimônio , Brasil , Linfócitos T CD8-Positivos/imunologia , Citocinas/metabolismo , Feminino , Granzimas , Humanos , Inflamação , Leishmania/imunologia , Leishmaniose Cutânea/patologia , Masculino , Metaloproteinase 9 da Matriz , Pessoa de Meia-Idade , Necrose , Pele/parasitologia , Pele/patologia , Adulto JovemRESUMO
BACKGROUND: Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by a single ulcer or multiple cutaneous lesions with raised borders. Cure rates <60% are observed in response to meglumine antimoniate therapy. We investigated the impact of obesity on CL clinical presentation and therapeutic response. METHODS: A total of 90 age-matched patients with CL were included (30 obese, 30 overweight, and 30 with normal body mass index [BMI]). CL was diagnosed through documentation of L. braziliensis DNA by polymerase chain reaction or identification of amastigotes in biopsied skin-lesion samples. Serum cytokine levels were determined by chemiluminescence. Antimony therapy with Glucantime (Sanofi-Aventis; 20 mg/kg/day) was administered for 20 days. RESULTS: Obese CL patients may present hypertrophic ulcers rather than typical oval, ulcerated lesions. A direct correlation between BMI and healing time was noted. After 1 course of antimony, cure was achieved in 73% of patients with normal BMI, 37% of overweight subjects, yet just 18% of obese CL patients (P < .01). Obese CL cases additionally presented higher leptin levels than overweight patients or those with normal BMI (P < .05). CONCLUSIONS: Obesity modifies the clinical presentation of CL and host immune response and is associated with greater failure to therapy.
Assuntos
Antiprotozoários , Leishmania braziliensis , Leishmaniose Cutânea , Antiprotozoários/uso terapêutico , Humanos , Leishmaniose Cutânea/tratamento farmacológico , Antimoniato de Meglumina/uso terapêutico , Obesidade/complicaçõesRESUMO
The severity of lesions that develop in patients infected by Leishmania braziliensis is mainly associated with a highly cytotoxic and inflammatory cutaneous environment. Recently, we demonstrated that senescent T and NK cells play a role in the establishment and maintenance of this tissue inflammation. Here, we extended those findings using transcriptomic analyses that demonstrate a strong co-induction of senescence and pro-inflammatory gene signatures in cutaneous leishmaniasis (CL) lesions. The senescence-associated signature was characterized by marked expression of key genes such as ATM, Sestrin 2, p16, p21 and p38. The cell type identification from deconvolution of bulk sequencing data showed that the senescence signature was linked with CD8+ effector memory and TEMRA subsets and also senescent NK cells. A key observation was that the senescence markers in the skin lesions are age-independent of patients and were correlated with lesion size. Moreover, a striking expression of the senescence-associated secretory phenotype (SASP), pro-inflammatory cytokine and chemokines genes was found within lesions that were most strongly associated with the senescent CD8 TEMRA subset. Collectively, our results confirm that there is a senescence transcriptomic signature in CL lesions and supports the hypothesis that lesional senescent cells have a major role in mediating immunopathology of the disease.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Imunossenescência/genética , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/etiologia , Leishmaniose Cutânea/patologia , Transcriptoma , Biomarcadores , Biópsia , Biologia Computacional/métodos , Citocinas/genética , Citocinas/metabolismo , Bases de Dados Genéticas , Suscetibilidade a Doenças/imunologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Humanos , Mediadores da Inflamação/metabolismo , Leishmaniose Cutânea/metabolismo , Carga Parasitária , Pele/patologiaRESUMO
Disseminated cutaneous leishmaniasis (DCL) is an uncommon form of Leishmania braziliensis infection. It remains unknown why some people develop this clinical condition. We describe 14 DCL patients in Northeast Brazil during 2015-2018. These patients regularly drank large amounts of alcohol, possibly increasing their risk for DCL.
Assuntos
Alcoolismo , Leishmania braziliensis , Leishmaniose Cutânea , Brasil/epidemiologia , Etanol , Humanos , Leishmaniose Cutânea/diagnóstico , Leishmaniose Cutânea/epidemiologiaRESUMO
Leishmania braziliensis is the main causative agent of American tegumentary leishmaniasis in Brazil. Current treatment includes different drugs that have important side effects and identification of cases of parasite resistance to treatment support the search for new therapeutic strategies. Recent findings have indicated that CXCL10, a chemokine that recruits and activates Th1 cells, NK cells, macrophages, dendritic cells and B lymphocytes, is a potential alternative to treat Leishmania infection. Here, we tested CXCL10 immunotherapy against experimental infection caused by an antimony-resistant isolate of Leishmania braziliensis. Following infection, mice were treated with CXCL10 for 7 days after onset of lesions. We demonstrate that mice treated with CXCL10 controlled lesion progression and parasite burden more efficiently comparing to controls. An increased IFN-γ, IL-10, TGF-ß and low IL-4 production combined with a distinct inflammatory infiltrate composed by activated macrophages, lymphocytes and granulomas was observed in the CXCL10-treated group comparing to controls. However, CXCL10 and Glucantime combined therapy did not improve CXCL10-induced protective effect. Our findings reinforce the potential of CXCL10 immunotherapy as an alternative treatment against infection caused by L. braziliensis resistant to conventional chemotherapy.
Assuntos
Quimiocina CXCL10/uso terapêutico , Fatores Imunológicos/uso terapêutico , Leishmania braziliensis/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Cutânea/parasitologia , Animais , Antimônio/farmacologia , Brasil , Feminino , Interleucina-10/imunologia , Leishmania braziliensis/imunologia , Leishmania braziliensis/isolamento & purificação , Leishmaniose Cutânea/imunologia , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/farmacologia , Células Th1/imunologiaRESUMO
Leishmania braziliensis is responsible for most cases of human tegumentary leishmaniasis (HTL) and has caused a wide range of clinical manifestations, including cutaneous (CL) and mucosal leishmaniasis (ML). The diagnosis is based on criteria that consider epidemiological data, clinical findings, and laboratory tests and is hard to establish. For laboratory tests, none of the assays available can be considered gold standards for disease detection. In addition, the Montenegro skin test, essential to supporting infectologists in the clinical management of the disease, is no longer available in Brazil. Thus, the aim of this study was to develop new targets to be used in diagnostic tests for HTL. In the first step, we carried out two-dimensional gel electrophoresis, followed by mass spectrometry, combined with heat map analysis and immunoproteomics approach, and disclosed eight proteins expressed in the amastigote stage specifically recognized by serum from CL and ML patients. A chimeric protein was designed based on the combination of thirteen linear B-cell epitopes, identified by immunoinformatics analysis, from L. braziliensis proteins. Our results showed that the strategy used in this work was successful in developing an antigen to be used in immunological assays (100.0% sensitivity and specificity) in the detection of HTL cases and in comparison with results obtained from an ELISA using soluble L. braziliensis antigen (SLb-Antigen) and immunofluorescence assay (Bio-Manguinhos/FIOCRUZ). The present technology opens the door for its use in field exams by means of an immunochromatographic test, which will be even more helpful in regions without laboratory structures.Key points⢠Rational strategy to develop antigens.⢠Integration between immunoproteomic and immunoinformatics analysis.⢠Chimeric protein shows high performance in HTL diagnosis.
Assuntos
Leishmania braziliensis , Leishmaniose Cutânea , Ensaio de Imunoadsorção Enzimática , Humanos , Leishmaniose Cutânea/diagnóstico , Proteômica , Proteínas Recombinantes de FusãoRESUMO
Leishmaniasis is one of the most neglected parasitic infections of the world and current therapeutic options show several limitations. In the search for more effective drugs, plant compounds represent a powerful natural source. Artemisinin is a sesquiterpene lactone extracted from Artemisia annua L. leaves, from which dihydroartemisinin (DQHS) and artesunic acid (AA)/artesunate are examples of active derivatives. These lactones have been applied successfully on malaria therapy for decades. Herein, we investigated the sensitivity of Leishmania braziliensis, one of the most prevalent Leishmania species that cause cutaneous manifestations in the New World, to artemisinin, DQHS, and AA. L. braziliensis promastigotes and the stage that is targeted for therapy, intracelular amastigotes, were more sensitive to DQHS, showing EC50 of 62.3 ± 1.8 and 8.9 ± 0.9 µM, respectively. Cytotoxicity assays showed that 50% of bone marrow-derived macrophages cultures were inhibited with 292.8 ± 3.8 µM of artemisinin, 236.2 ± 4.0 µM of DQHS, and 396.8 ± 6.7 µM of AA. The control of intracellular infection may not be essentially attributed to the production of nitric oxide. However, direct effects on mitochondrial bioenergetics and H2O2 production appear to be associated with the leishmanicidal effect of DQHS. Our data provide support for further studies of artemisinin and derivatives repositioning for experimental leishmaniasis.
Assuntos
Antiprotozoários/farmacologia , Artemisininas/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Animais , Metabolismo Energético/efeitos dos fármacos , Peróxido de Hidrogênio/metabolismo , Leishmania braziliensis/metabolismo , Macrófagos/efeitos dos fármacos , Macrófagos/parasitologia , Mitocôndrias/metabolismo , Succinatos/farmacologiaRESUMO
Photodynamic therapy (PDT) with photosensitizer methylene blue was applied to Leishmania braziliensis, and Fourier transform infrared (FTIR) spectroscopy was used to study biochemical changes in the parasite after PDT in comparison to untreated (C), only irradiation (I), and only photosensitizer (PS). Spectral analysis suggests increase in lipids, proteins, and protein secondary structures in PDT compared with C and decrease in nucleic acids and carbohydrates. Interestingly, these trends are different from PDT of Leishmania major species, wherein lipids decrease; there are minimal changes in secondary structures and increase in nucleic acids and carbohydrates. The study thus suggests possibility of different biomolecular players/pathways in PDT-induced death of L. braziliensis and L. major.
Assuntos
Leishmania braziliensis/metabolismo , Azul de Metileno/farmacologia , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Espectroscopia de Infravermelho com Transformada de Fourier , Leishmania braziliensis/efeitos dos fármacos , Leishmania braziliensis/efeitos da radiação , Proteínas de Protozoários/metabolismoRESUMO
The natural products pulchrol and pulchral, isolated from the roots of the Mexican plant Bourreria pulchra, have previously been shown to possess antiparasitic activity towards Trypanosoma cruzi, Leishmania braziliensis and L. amazonensis, which are protozoa responsible for Chagas disease and leishmaniasis. These infections have been classified as neglected diseases, and still require the development of safer and more efficient alternatives to their current treatments. Recent SARs studies, based on the pulchrol scaffold, showed which effects exchanges of its substituents have on the antileishmanial and antitrypanosomal activity. Many of the analogues prepared were shown to be more potent than pulchrol and the current drugs used to treat leishmaniasis and Chagas disease (miltefosine and benznidazole, respectively), in vitro. Moreover, indications of some of the possible interactions that may take place in the binding sites were also identified. In this study, 12 analogues with modifications at two or three different positions in two of the three rings were prepared by synthetic and semi-synthetic procedures. The molecules were assayed in vitro towards T. cruzi epimastigotes, L. braziliensis promastigotes, and L. amazonensis promastigotes. Some compounds had higher antiparasitic activity than the parental compound pulchrol, and in some cases even benznidazole and miltefosine. The best combinations in this subset are with carbonyl functionalities in the A-ring and isopropyl groups in the C-ring, as well as with alkyl substituents in both the A- and C-rings combined with a hydroxyl group in position 1 (C-ring). The latter corresponds to cannabinol, which indeed was shown to be potent towards all the parasites.
Assuntos
Benzopiranos , Leishmania braziliensis/crescimento & desenvolvimento , Tripanossomicidas , Trypanosoma cruzi/crescimento & desenvolvimento , Benzopiranos/química , Benzopiranos/farmacologia , Doença de Chagas/tratamento farmacológico , Humanos , Leishmaniose Cutânea/tratamento farmacológico , Tripanossomicidas/química , Tripanossomicidas/farmacologiaRESUMO
Cytotoxic activity mediated by CD8+ T cells is the main signature of the immunopathogenesis of cutaneous leishmaniasis (CL). Here, we performed a broad evaluation of natural killer (NK) cell phenotypic and functional features during cutaneous leishmaniasis. We demonstrate for the first time that CL patients present the accumulation of circulating NK cells with multiple features of replicative senescence including low proliferative capacity and shorter telomeres, elevated expression of CD57, KLRG1 but diminished CD27 stimulatory receptor expression. Moreover, they exhibited higher cytotoxic and inflammatory potential than age-matched controls. The accumulation of circulating senescent NK cells (CD56dim CD57bright ) correlated positively with skin lesion size in the same patients, suggesting that they, like circulating senescent CD8+ T cells, may contribute to the immunopathology of CL. However, this senescent population had lower cutaneous lymphocyte antigen expression and so had diminished skin-homing potential compared with total or senescent CD8+ T cells. This was confirmed in CL skin lesions where we found a predominance of CD8+ T cells (both senescent and non-senescent) that correlated with the severity of the disease. Although there was also a correlation between the proportions of senescent NK cells (CD56+ CD57+ ) in the skin and lesion size, this was less evident. Collectively our results demonstrate first-hand that senescent cytotoxic cells may mediate skin pathology during human cutaneous leishmaniasis. However, as senescent cytotoxic CD8+ T cells predominate in the skin lesions, they may have a greater role than NK cells in mediating the non-specific skin damage in CL.
Assuntos
Citotoxicidade Imunológica , Células Matadoras Naturais/patologia , Leishmania braziliensis/patogenicidade , Leishmaniose Cutânea/patologia , Pele/patologia , Linfócitos T Citotóxicos/patologia , Antígeno CD56/genética , Antígeno CD56/imunologia , Antígenos CD57/genética , Antígenos CD57/imunologia , Estudos de Casos e Controles , Senescência Celular/imunologia , Feminino , Regulação da Expressão Gênica , Interações Hospedeiro-Parasita/genética , Interações Hospedeiro-Parasita/imunologia , Humanos , Interferon gama/genética , Interferon gama/imunologia , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/parasitologia , Lectinas Tipo C/genética , Lectinas Tipo C/imunologia , Leishmania braziliensis/imunologia , Leishmaniose Cutânea/imunologia , Leishmaniose Cutânea/parasitologia , Masculino , Oligossacarídeos/genética , Oligossacarídeos/imunologia , Receptores Imunológicos/genética , Receptores Imunológicos/imunologia , Índice de Gravidade de Doença , Antígeno Sialil Lewis X/análogos & derivados , Antígeno Sialil Lewis X/genética , Antígeno Sialil Lewis X/imunologia , Transdução de Sinais , Pele/imunologia , Pele/parasitologia , Linfócitos T Citotóxicos/imunologia , Linfócitos T Citotóxicos/parasitologiaRESUMO
Leishmaniasis is caused by several species of protozoan parasites of the genus Leishmania and represents an important global health problem. Leishmania braziliensis in particular is responsible of cutaneous and mucocutaneous forms of this parasitosis, with prevalence in Latin America. In the present work, we describe in L. braziliensis promastigotes and amastigotes the presence of a Phospholipase A1 (PLA1) activity, an enzyme that catalyses extensive deacylation of phospholipids like phosphatidylcholine. In order to deepen the knowledge about L. braziliensis PLA1, the cloning and expression of the gene that codifies for this enzyme was carried out in a baculovirus expression system with the obtaintion of a purified recombinant protein that displayed PLA1 activity. Given that this is the first molecular and functional protein characterization of a PLA1 in the Leishmania genus, we also performed a phylogenetic analysis of this gene throughout 12 species whose genome sequences were available. The results presented here will contribute to increase the knowledge about trypanosome phospholipases, which could be novel and valuable as potential targets to fight neglected diseases like Leishmaniasis.
Assuntos
Leishmania braziliensis , Fosfolipases A1 , Animais , Baculoviridae/genética , Clonagem Molecular/métodos , Expressão Gênica , Genes de Protozoários , América Latina , Leishmania braziliensis/genética , Leishmania braziliensis/metabolismo , Leishmaniose Cutânea/parasitologia , Fosfolipases A1/genética , Fosfolipases A1/isolamento & purificação , Fosfolipases A1/metabolismo , Filogenia , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Células Sf9RESUMO
Cutaneous leishmaniasis (CL) is a common disease affecting millions in endemic areas worldwide. We present a case of lupoid leishmaniasis, a rare variant of CL, which clinically mimicked sarcoidosis and/or granulomatous rosacea for 10 years until ultimate diagnosis. An 82-year-old U.S. citizen with an extensive travel history presented with a 10-year history of facial plaques on the cheeks and was previously diagnosed and treated as sarcoidosis. Multiple biopsies (previously and at presentation) revealed tuberculoid granulomas with negative special stains for microorganisms and negative sterile tissue cultures for acid-fast bacilli, bacteria, and fungal organisms. A diagnosis of granulomatous rosacea was rendered and multiple medical therapies were attempted, none with sustained improvement. Repeat biopsy of a new lesion revealed intracellular organisms consistent with leishmaniasis, which was confirmed by polymerase chain reaction (PCR). Lupoid leishmaniasis is a rare presentation of CL including facial plaques that can mimic granulomatous diseases affecting the face including sarcoidosis and granulomatous rosacea. CL can sometimes be challenging to diagnose through standard histopathologic examination; immunohistochemistry for CD1a can be used to augment tissue-based examination and PCR should be sent early in cases with sufficient concern.