Uso de anfotericina B liposomal en leishmaniasis cutánea diseminada causada por Leishmania braziliensis en un paciente pediátrico con síndrome de Down / Use of liposomal anfotericin B in diseminated cutaneous leishmaniasis caused by Leishmania braziliensis in a pediatric patient with Down syndrome

Se presenta un caso de leishmaniasis selvática cutánea diseminada con manifestación extensa en una paciente pediátrica con síndrome de Down. El caso se confirmó a través de estudios parasitológicos e inmunológicos, mientras que la identificación se realizó mediante la técnica de reacción en cadena de la polimerasa-polimorfismos de longitud de fragmentos de restricción (PCR-RFLP, por sus siglas en inglés), determinándose la especie como Leishmania (Viannia) braziliensis. La manifestación clínica agresiva y prolongada con poca respuesta a estibogluconato y anfotericina desoxicolato pueden deberse al déficit inmunológico que se presenta como parte del síndrome de Down. La paciente eventualmente recibió tratamiento con anfotericina B liposomal y al término de la terapia, mostró mejoría clínica de las lesiones. El presente reporte ilustra los desafíos tanto de diagnóstico como tratamiento de leishmaniasis cutánea en pacientes pediátricos inmunosuprimidos, especialmente en un entorno de difícil acceso social, económico y geográfico, a los servicios de salud. Se recomienda considerar a la leishmaniasis en el diagnóstico diferencial cuando se atienda ulceras crónicas dermatológicas atípicas; así como tener en cuenta el uso de anfotericina liposomal en pacientes inmunocomprometidos.

We present a case of disseminated cutaneous leishmaniasis with extensive manifestation in a pediatric patient with Down syndrome. The case was confirmed by parasitological and immunological tests. The species was identified as Leishmania (Viannia) braziliensis by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). The immune deficit that occurs as part of Down syndrome may have been the reason for the aggressive and prolonged clinical manifestations as well as the poor response to stibogluconate and deoxycholate amphotericin. The patient was treated with liposomal amphotericin B and at the end of therapy, showed clinical improvement of the lesions. This report highlights the challenges of the diagnosis and treatment of cutaneous leishmaniasis in immunosuppressed pediatric patients, especially under difficult social, economic and geographic conditions. Leishmaniasis should be considered as a differential diagnosis when treating atypical chronic dermatologic ulcers; the use of liposomal amphotericin in immunocompromised patients should also be considered in these cases.

Desenvolvimento e avaliação de uma proteína quimérica recombinante para o diagnóstico e prognóstico das leishmanioses tegumentar e visceral / Development and evaluation of a recombinant chimeric protein for the diagnosis and prognosis of tegumentary and visceral leishmaniasis

As leishmanioses são doenças tropicais negligenciadas com alta endemicidade e que afetam milhares de pessoas no mundo. Sua infecção é causada por parasitos protozoários do gênero Leishmania. A diversidade biológica entre as espécies é quem permite determinar as manifestações clínicas, sendo elas na forma de leishmaniose visceral (LV) ou leishmaniose tegumentar (LT). Dentre estas manifestações, a LV é considerada a mais grave, devido sua alta letalidade e grande emergência em indivíduos com a infecção provocada pelo vírus da imunodeficiência humana (HIV). Atualmente, as medidas de controle e prevenção adotadas pela Organização Mundial da Saúde (OMS), baseiam-se em uma combinação de estratégias de intervenção contra a infecção, uma vez que o diagnóstico eficaz e precoce é indispensável para que se possa intervir com o tratamento adequado, diminuindo índices de mortalidade e a evolução de complicações clínicas. Entretanto, os testes sorológicos utilizados apresentam sensibilidade e especificidade prejudicadas em pacientes com leishmanioses e/ou coinfectados LV/HIV, devido a baixos ní-veis de anticorpos antileishmanial ou pela presença de doenças que causem reação cruzada, levando a resultados falso-positivos. A sensibilidade torna-se também variável em pacientes tratados, uma vez que a sorologia pode manter-se positiva por meses ou anos após o fim do tratamento e cura da doença. Buscando resolver tal problemática, a identificação de novos antígenos, por meio de análises de bioinformática associadas à imunoproteômica, tem permitido a detecção de novas proteínas com potencial aplicação diagnóstica. Em estudos anteriores, as proteínas hipotéticas LiHyT, LiHyD, LiHyV e LiHyP foram encontradas em espécies de Leishmania spp, e avaliadas em suas versões recombinantes por meio de ensaios de ELISA, obtendo resultados satisfatórios para a detecção da LV humana e canina. Com base nessas informações, o presente trabalho teve como objetivo desenvolver uma proteína quimera recombinante base-ada na predição de epítopos lineares específicos de células B das quatro proteínas antigênicas de L. infantum citadas e avaliar o potencial diagnóstico, assim como dos peptídeos individuais que a constituíram, frente à leishmaniose humana, bem como com a coinfecção com HIV, além de testar os antígenos como marcadores prognóstico após o tratamento da LV e LT. As sequências de aminoácidos das proteínas foram avaliadas e oito epítopos de células B foram preditos e utilizados na construção de uma nova proteína quimérica. A proteína foi expressa, purificada e avaliada como antígeno recombinante em ELISA para o diagnóstico de LV, LT, coinfecção LV/HIV e prognóstico em amostras de pacientes tratados de LV e LT. Os epítopos de células B usados na construção da quimera foram sintetizados e também testados em ELISA frente às mesmas amostras, assim como um extrato antigênico solúvel de Leishmania braziliensis (SLA). Os resultados mostraram que a proteína quimera apresentou sensibilidade e especificidade de 100% para diagnosticar a LV, LT e LV/HIV, enquanto os peptídeos sintéticos apresentaram sensibilidade variando entre eles de 9,1% a 90,9% para amostras de LT e 76,8% a 99,2% para amostras de LV e LV/HIV, já os valores de especificidade atingiram 98,3% a 99,1% para LT e 67,1% a 95,7% para LV e LV/HIV. O SLA apresentou sensibilidade e especificidade de 18,2% e 98,3% para LT, e 56,8% a 69,5% para amostras de LV e LV/HIV, respectivamente. Uma avaliação prognóstica preliminar mostrou ainda que os anticorpos anti-quimera diminuíram em níveis significativos, quando comparada a reatividade sorológica antes e seis meses após o tratamento, sugerindo um possível papel prognóstico da quimera para as leishmanioses. O presente estudo, mostrou-se eficaz na construção e avaliação de novos candidatos, que demonstram ter um bom desempenho na detecção diagnóstica e prognóstica para as leishmanioses e dos casos de coinfecção LV/HIV.

Leishmaniasis are neglected tropical diseases with high endemicity that affect thousands of people in the world. Infection is caused by protozoan parasites of the genus Leishmania. The biological diversity between species is what allows determining the clinical manifestations, either in the form of visceral leishmaniasis (VL) or tegumentary leishmaniasis (TL). Among these clinical manifestations, VL is considered the most serious, due to its high lethality and great emergence in individuals with infection caused by the human immunodeficiency virus (HIV). Currently, the control and prevention measures adopted by the World Health Organiza-tion (WHO) are based on a combination of intervention strategies against the infection, since an effective and early diagnosis is essential to intervene with the appropriate treatment, decrea-sing mortality rates and evolution of clinical complications. However, the serological tests used show impaired sensitivity and specificity in patients with leishmaniasis and/or coinfected with VL/HIV, due to low levels of anti-leishmanial antibodies or the presence of diseases that cause cross-reaction, leading to false-positive results. The sensitivity also becomes variable in treated patients, since the serology can remain positive for months or years after the end of the trea-tment and cure of the disease. Seeking to solve this problem, the identification of new antigens, through bioinformatic analysis associated with immunoproteomic, has allowed the detection of new proteins with potential diagnostic application. In previous studies, the hypothetical proteins LiHyT, LiHyD, LiHyV and LiHyP were found in species of Leishmania spp, and evaluated in their recombinant versions through ELISA assays, and satisfactory results were obtained for the detection of human and canine VL. Based on this information, the present work aimed to develop a recombinant chimera protein through on the prediction of specific linear epitopes of B cells derived from these four antigenic proteins of L. infantum and to evaluate its diagnostic potential, as well as the individual peptides that constitute it, against human leishmaniasis, as well as co-infection with HIV, in addition to testing them as possible prognostic markers of patients after VL and TL treatment. The amino acid sequences of the proteins were evaluated and eight B cell epitopes were predicted and used in the construction of a new chimeric protein. The protein was expressed, purified and evaluated as a recombinant antigen in ELISA for the diagnosis of VL, TL, VL/HIV co-infection and prognosis in samples from patients treated for VL and TL. The B cell epitopes used in the construction of the chimera were synthesized and also tested in ELISA against the same samples, as well as a soluble Leishmania braziliensis antigenic extract (SLA). The results showed that the chimera protein apresented sensitivity and specificity of 100% for diagnosing VL, TL and VL/HIV, while the synthetic peptides showed sensitivity ranging from 9.1% to 90.9% for TL samples and 76.8 % to 99.2% for VL and VL/HIV samples, while the specificity values reached from 98.3% to 99.1% for TL and 67.1% to 95.7% for VL and VL/HIV. The SLA showed sensitivity and specificity of 18.2% and 98.3% for TL, and 56.8% to 69.5% for VL and VL/HIV samples, respectively. A preliminary prog-nostic evaluation also showed that anti-chimera antibodies significantly decreased when com-pared to serological reactivity before and six months after treatment, suggesting a possible prognostic role of the antigen for leishmaniasis. The present study proved to be effective in the construction and evaluation of new candidates, who demonstrate good performance in diagnos-tic and prognostic detection for leishmaniasis and VL/HIV co-infection.

Exuberant case of verrucous cutaneous leishmaniasis

Abstract Cutaneous leishmaniasis represents a public health problem that affects 85 countries. It is an endemic disease in Brazil, having an important socioeconomic impact. An exuberant case of cutaneous leishmaniasis is reported herein. A 28-year-old male patient with Down syndrome had had verrucous plaques on the back for over a year, with progressive growth. PCR of a lesion sample was positive for Leishmania braziliensis. The patient's condition was classified as atypical cutaneous leishmaniasis. He was successfully treated with amphotericin B and miltefosine. The treatment remains a challenge, given the toxicity and low cure rate of the currently recommended drugs.

Anti-leishmanial activity of 29 daily sessions of intralesional-pentavalent antimony administration on Leishmania (Viannia)-infected BALB/c mice / Actividad antileishmania de 29 sesiones diarias de antimonio pentavalente intralesional en ratones BALB/c infectados con Leishmania (Viannia)

Abstract Introduction: Intralesional-pentavalent antimonials (IL-SbV) are recommended for simple cutaneous leishmaniasis (CL). Few treatment sessions (1-5) and drug volumes (1-5 ml each), relative to lesion size (LS), are recommended. There is not a validated IL-SbV protocol using doses calculated as mg/kg body weight and administered over a large number of IL-sessions, with small injection volumes. Objective: The study aim was to determine the efficacy of different concentrations of IL-SbV administered in 29 daily sessions of 100 μL each, on CL infected mice. Methods: Leishmania (Viannia) panamensis and L. (V.) braziliensis-infected mice (N = 6) were treated with 150, 50, and 16.6 mgSbV/kg/day x 29 days. Percentage of lesion area reduction, aesthetic and final (no lesions, no parasites) efficacy and effective dose (ED)50 were determined. In vitro-SbV activity against parasites was evaluated for both species. Results: The ED50 values were 72.2 and 66.3 (at the end of treatment), 54.3 and 37.7 (15-days pt.), and 145.3 and 148.6 (60-days pt.) for each species, respectively. Differences were observed between Leishmania species at 15-days pt., but not later. At 60-day pt., IL-SbV-150 mg showed final cure rates of 66.6 % for L. (V.) panamensis and 33.3 % for L. (V.) braziliensis-infected mice. After 15 days pt., lesion reactivation was observed in some "aesthetically cured" mice. Glucantime was not active in in vitro assays. Conclusions: The IL-SbV use with a dose calculated as mg/kg body weight and administered over a large number of IL-sessions, with small injection volumes each day could be effective against L. (V.) panamensis and L. (V.) braziliensis-CL infection. An appropriate SbV-dose (higher than 150 mg/kg/day x less than 29 days) must be evaluated.

Resumen Introducción: Los antimoniales pentavalentes aplicados intralesionalmente (IL-SbV) se recomiendan para el tratamiento de la leishmaniasis cutánea (LC) simple. Se recomiendan pocas sesiones (1-5) y volúmenes (1-5 ml cada uno) en relación con el tamaño de la lesión (LS). No existe un protocolo de IL-SbV validado que utilice dosis calculadas según el peso corporal (en mg/kg) y administradas durante varias sesiones en pocos volúmenes de inyección. Objetivo: El objetivo del estudio fue determinar la eficacia de diferentes concentraciones de IL-SbV administradas en 29 sesiones diarias de 100 μL cada una, en ratones con LC. Métodos: Ratones infectados con L. (V.) panamensis y L. (V.) braziliensis (N = 6) fueron tratados intralesionalmente con 150, 50 y 16,6 mg SbV/kg/día x 29 días. Se determinó el porcentaje de reducción del área de la lesión, la eficacia estética y final (sin lesiones, sin parásitos) y la dosis efectiva (DE)50. Adicionalmente de evaluó la actividad in vitro del SbV. Resultados: Los valores de DE50 fueron 72.2 y 66.3 (al final del tratamiento), 54.3 y 37.7 (15 días pt) y 145.3 y 148.6 (60 días pt) para cada especie. Se encontraron diferencias entre las especies sólo a los 15 días pt. La eficacia del tratamiento IL-SbV-150 mg, 60 días pt., fue de 66.6 y 33.3 % en ratones infectados con L. (V.) panamensis L. (V.) braziliensis respectivamente. Después de 15 días pt., se observó reactivación de la lesión en algunos ratones "estéticamente curados". Glucantime no fue activo in vitro. Conclusiones: El uso intralesional de SbV con una dosis calculada en mg/kg de peso corporal y administrada durante varias sesiones, con pequeños volúmenes de inyección cada día, podría ser eficaz en LC por L. (V.) panamensis y L. (V.) braziliensis. Dosis adecuadas de SbV (superiores a 150 mg/kg/día x 20) deben evaluarse.

Detección de Leishmania (viannia) braziliensis en piel de oreja de Rattus rattus que habitan área urbana de la ciudad de Corrientes

Resumen La leishmaniasis cutánea es una enfermedad zoonótica que se transmite al hombre y a los animales a través de la picadura de insectos dípteros de los géneros Phlebotomus y Lutzomyia infectados con diferentes especies de protozoos del género Leishmania. En América Latina el principal agente etiológico responsable de esta parasitosis es la especie L. braziliensis. Si bien se han identificado numerosas especies de mamíferos infectados naturalmente con especies de Leishmania, los roedores cumplirían un rol importante en el ciclo de transmisión de la enfermedad. El presente trabajo tuvo como objetivo la identificación de especie de leishmania que circula en roedores sinantrópicos que habitan el área urbana de la ciudad de Corrientes. Se trabajó con muestras de piel de oreja de roedores a los que se les aplicó las técnicas de Nested PCR para la identificación de Leishmania spp y PCR Simple para la detección de L. braziliensis. Se analizó un total de 30 muestras de roedores de la especie Rattus rattus de los cuales 2 muestras resultaron detectables a Nested PCR. Seguidamente, a las muestras detectables a Leishmania spp. se les aplicó PCR Simple a L. braziliensis resultando ambas detectables a esta especie. Si bien los valores obtenidos en este trabajo no son altos para poder considerarlos como reservorios, si se evidencia una infección natural que no afecta clínicamente a los roedores estudiados con circulación del parásito en piel, particularmente de la especie L. braziliensis.

Abstract Cutaneous leishmaniasis is a zoonotic disease that is transmitted to man and animals through the bite of dipteran insects of the genera Phlebotomus and Lutzomyia infected with different species of protozoa of the genus Leishmania. In Latin America the main etiological agent responsible for this parasitosis is the species L. braziliensis. Although numerous species of mammals have been identified naturally infected with Leishmania species, rodents would play an important role in the transmission cycle of the disease. The present work aimed to identify the species of leishmania that circulates in synanthropic rodents that inhabit the urban area of the city of Corrientes. We worked with rodent ear skin samples to which the Nested PCR techniques were applied for the identification of Leishmania spp and Simple PCR for the detection of L. braziliensis. A total of 30 rodent samples of the species Rattus rattus were analyzed, of which 2 samples were detectable by Nested PCR. Next, the samples detectable to Leishmania spp. Simple PCR was applied to L. braziliensis, both of which were detectable in this species. Although the values obtained in this work are not high to be considered as reservoirs, there is evidence of a natural infection that does not clinically affect the rodents studied with circulation of the parasite on the skin, particularly of the L. braziliensis species.

Identificación de una triparedoxina peroxidasa citoplasmática en Leishmania braziliensis / Identification of a cytoplasmic tryparedoxin peroxidase from Leishmania braziliensis / Identificação de uma triparedoxina peroxidase citoplasmica de Leishmania braziliensis

Resumen Los sistemas de defensa anti-oxidante utilizados por el parásito intracelular Leishmania braziliensis durante el proceso de infección permiten eliminar especies reactivas de oxígeno y nitrógeno a expensas de equivalentes reductores derivados de la tripanotiona, evitando daños celulares del patógeno. Con el objetivo de identificar potenciales blancos moleculares para el desarrollo de fármacos contra este parásito, se realizó la detección de la enzima triparedoxina peroxidasa citoplasmática de L. braziliensis (LbTXNPxII), la cual es esencial para disminuir concentraciones tóxicas de peróxido de hidrógeno en el contexto de infección. Para esto se generaron anticuerpos policlonales en modelo aviar, partiendo de la clonación, expresión y purificación de la proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) en el sistema heterólogo Escherichia coli. La proteína purificada se utilizó como antígeno para la producción de anticuerpos IgY, cuya implementación en estudios in situ permitió detectar y localizar la enzima LbTXNPxII endógena (22kDa) en el citoplasma de promastigotes fijados y verificar su interacción molecular con la nicotinamida/ nicotinato mononucleótido adenilil transferasa, enzima involucrada en la síntesis del NAD. De este modo, se reporta el desarrollo de una herramienta bioquímica para la identificación y estudio de la enzima LbTXNPxII y su participación en vías del metabolismo energético y de defensa anti-oxidante.

Abstract The antioxidant defense systems used by the intracellular parasite Leishmania braziliensis during the infection process make it possible to eliminate reactive oxygen and nitrogen species at the expense of reducing equivalents derived from trypanothione, avoiding cellular damage of the pathogen. In order to identify potential molecular targets for the development of drugs against this parasite, the cytoplasmic tryparedoxin peroxidase of L. braziliensis (LbTXNPxII), which is essential to reduce toxic concentrations of hydrogen peroxide in the context of infection, was carried out. In this regard, polyclonal antibodies were generated in an avian model, starting from the cloning, expression, and purification of the recombinant protein 6xHis-SUMO-LbTXNPxII (37kDa) in the heterologous system of Escherichia coli. The purified protein was used as an antigen for the production of IgY antibodies, whose implementation in in situ experiments allowed the detection and localization of the endogenous LbTXNPxII enzyme (22kDa) in the cytoplasm of fixed promastigotes, as well as the verification of its molecular interaction with nicotinamide/nicotinate mononucleotide adenylyltransferase, an enzyme involved in the synthesis of NAD. Thus, the development of a biochemical tool for the identification and study of the LbTXNPxII enzyme and its participation in energy metabolism and antioxidant defense pathways is reported.

Resumo Os sistemas de defesa antioxidante utilizados pelo parasita intracelular Leishmania braziliensis durante o processo de infecção, permitem a eliminação de espécies reativas de oxigênio e nitrogênio em detrimento de equivalentes redutores derivados de tripanotiona, evitando o dano celular do patógeno. Com o objetivo de identificar potenciais alvos moleculares para o desenvolvimento de drogas contra esse parasita, foi detectada a enzima citoplasmática triparedoxina peroxidase de L. braziliensis (LbTXNPxII), essencial para reduzir as concentrações tóxicas de peróxido de hidrogênio no contexto de infecção. Para isso, anticorpos policlonais foram gerados em modelo aviário, a partir da clonagem, expressão e purificação da proteína recombinante 6xHis-SUMO-LbTXNPxII (37kDa) no sistema heterólogo de Escherichia coli. A proteína purificada foi utilizada como antígeno para a produção de anticorpos IgY, cuja implementação em experimentos in situ permitiu a detecção e localização da enzima LbTXNPxII endógena (22kDa) no citoplasma de promastigotas fixos e verificar sua interação molecular com nicotinamida/nicotinato mononucleotídeo adenililtransferase, enzima envolvida na síntese de NAD. Assim, é relatado o desenvolvimento de uma ferramenta bioquímica para a identificação e estudo da enzima LbTXNPxII e sua participação no metabolismo energético e nas vias de defesa antioxidante.

Regulación de la actividad enzimática de la NMNAT de Leishmania braziliensis por péptidos representativos de su extremo N-terminal / Regulation of the enzymatic activity of the NMNAT of Leishmania braziliensis by representative peptides derived from its N-terminus end / Regulação da atividade enzimática do NMNAT de Leishmania braziliensis por peptídeos representativos derivados de sua extremidade N-terminal

Resumen El parásito intracelular Leishmania braziliensis es el agente causal de la leishmaniasis cutánea, enfermedad endémica de zonas tropicales, cuyos tratamientos farmacológicos son tóxicos y para la cual no se dispone de una vacuna en la actualidad. Por esta razón, el estudio de las proteínas relacionadas con el metabolismo energético del parásito es relevante dada su importancia para la supervivencia del mismo. En este estudio, utilizando como secuencia plantilla los primeros 18 residuos del extremo N-terminal de la proteína nicotinamida/ nicotinato mononucleótido adenilil transferasa de L. braziliensis (Lb-NMNAT), se sintetizaron péptidos implementando la estrategia Fmoc/ tert-Butilo en una resina Rink amida MBHA. Los péptidos se purificaron por cromatografía en columna C18 y se caracterizaron mediante RP-HPLC. La proteína recombinante 6xHisLb-NMNAT se expresó en células Escherichia coli M15 y se purificó parcialmente empleando cromatografía de afinidad a metales inmovilizados. De esta proteína se confirmó su actividad enzimática a través de ensayos enzimáticos directos analizados por RP-HPLC. Los péptidos sintetizados se utilizaron para evaluar su efecto sobre la actividad enzimática de la proteína 6xHisLb-NMNAT, observándose una modulación diferencial, lo cual resulta promisorio para el diseño de herramientas quimioterapéuticas basadas en la secuencia N-terminal de la proteína Lb-NMNAT.

Abstract The intracellular parasite Leishmania braziliensis is the etiological agent of cutaneous leishmaniasis, an endemic disease in the tropics, whose pharmacological treatments are toxic and for which there is currently no vaccine. For this reason, the study of proteins related to the energy metabolism of the parasite is relevant given its importance for its survival. In this study, based on the first 18 residues of the N-terminal end of the nicotinamide/nicotinate mononucleotide adenylyl transferase protein from L. braziliensis (Lb-NMNAT) as a template, peptides were synthesized implementing the Fmoc/tert-Butyl strategy in a Rink amide MBHA resin. The peptides were purified by C18 column chromatography and characterized by RP-HPLC. The recombinant 6xHisLb-NMNAT protein was expressed in Escherichia coli M15 cells and partially purified using immobilized metal affinity chromatography. The enzymatic activity of the protein was confirmed through direct enzymatic assays analyzed by RP-HPLC. The synthesized peptides were used to evaluate their effect on the enzymatic activity of the 6xHisLb-NMNAT protein, observing a differential modulation, which is promising for the design of chemotherapeutic tools based on the N-terminal sequence of the Lb-NMNAT protein.

Resumo O parasita intracelular Leishmania braziliensis é o agente causador da leishmaniose tegumentar, doença endêmica nos trópicos, cujos tratamentos farmacológicos são tóxicos e para a qual não existe vacina atualmente. Por este motivo, o estudo de proteínas relacionadas ao metabolismo energético do parasita é relevante dada a sua importância para a sua sobrevivência. Neste estudo, usando os primeiros 18 resíduos da extremidade N-terminal da proteína adenilil transferase de nicotinamida/mononucleotídeo nicotinato de L. braziliensis (Lb-NMNAT) como uma sequência modelo, os peptídeos foram sintetizados implementando a estratégia Fmoc/tert-Butil em uma resina Rink amida MBHA. Os peptídeos foram purificados por cromatografia em coluna C18 e caracterizados por RP-HPLC. A proteína recombinante 6xHisLb-NMNAT foi expressa em células de Escherichia coli M15 e parcialmente purificada usando cromatografia de afinidade com metal imobilizado. Desta proteína, sua atividade enzimática foi confirmada por meio de ensaios enzimáticos diretos analisados por RP-HPLC. Os peptídeos sintetizados foram utilizados para avaliar seu efeito na atividade enzimática da proteína 6xHisLb-NMNAT, observando uma modulação diferencial, o que é promissor para o projeto de ferramentas quimioterápicas baseadas na sequência N-terminal da proteína Lb-NMNAT

Cross-linking mass spectrometry reveals structural insights of the glutamine synthetase from Leishmania braziliensis

BACKGROUND Leishmaniasis is a neglected tropical disease caused by the parasite Leishmania braziliensis, commonly found in Brazil and associated with cutaneous and visceral forms of this disease. Like other organisms, L. braziliensis has an enzyme called glutamine synthetase (LbGS) that acts on the synthesis of glutamine from glutamate. This enzyme plays an essential role in the metabolism of these parasites and can be a potential therapeutic target for treating this disease. OBJECTIVES Investigate LbGS structure and generate structural models of the protein. METHODS We use the method of crosslinking mass spectrometry (XLMS) and generate structural models in silico using I-TASSER. FINDINGS 42 XLs peptides were identified, of which 37 are explained in a monomeric model with the other five indicating LbGS dimerization and pentamers interaction region. The comparison of 3D models generated in the presence and absence of XLMS restrictions probed the benefits of modeling with XLMS highlighting the inappropriate folding due to the absence of spatial restrictions. MAIN CONCLUSIONS In conclusion, we disclose the conservation of the active site and interface regions, but also unique features of LbGS showing the potential of XLMS to probe structural information and explore new drugs.

Clinical and epidemiological aspects of American cutaneous leishmaniasis with genital involvement

Abstract Genital lesions are an unusual presentation of American cutaneous leishmaniasis. Conditions such as disseminated cutaneous leishmaniasis and HIV infection may be associated with genital involvement. The authors present five cases of American cutaneous leishmaniasis with genital lesions and discuss the clinical and epidemiological aspects observed in this case series.

Identification of Leishmania species by high-resolution DNA dissociation in cases of American cutaneous leishmaniasis

Abstract Background American cutaneous leishmaniasis is an infectious dermatosis caused by protozoa of the genus Leishmania, which comprises a broad spectrum of clinical manifestations depending on the parasite species involved in the infections and the immunogenetic response of the host. The use of techniques for amplification of the parasites DNA based on polymerase chain reaction polymerase chain reaction and the recent application of combined techniques, such as high-resolution DNA dissociation, have been described as a viable alternative for the detection and identification of Leishmania spp. in biological samples. Objectives To identify the Leishmania species using the polymerase chain reaction high-resolution DNA dissociation technique in skin biopsies of hospital-treated patients, and compare with results obtained by other molecular identification techniques. Methods A retrospective study assessing patients with suspected American cutaneous leishmaniasis seen at a hospital in São Paulo/Brazil was conducted. The paraffin blocks of 22 patients were analyzed by polymerase chain reaction high-resolution DNA dissociation to confirm the diagnosis and identify the species. Results Of the 22 patients with suspected American cutaneous leishmaniasis, the parasite was identified in 14, comprising five cases (35.6%) of infection by L. amazonensis, four (28.5%) by L. braziliensis, two (14.4%) by L. amazonensis + L. infantum chagasi, two (14.4%) by L. guyanensis, and one (7.1%) by Leishmania infantum chagasi. In one of the samples, in which the presence of amastigotes was confirmed on histopathological examination, the polymerase chain reaction high-resolution DNA dissociation technique failed to detect the DNA of the parasite. Study limitations The retrospective nature of the study and small number of patients. Conclusions The method detected and identified Leishmania species in paraffin-embedded skin biopsies with a sensitivity of 96.4% and could be routinely used in the public health system.

Leishmaniasis en Bolivia, revisión y estado actual en Tarija, frontera con Argentina / Leishmaniasis en Bolivia. Comprehensive review and current status in Tarija, in the border with Argentina

Introducción. En 1997, en el departamento de Tarija, Bolivia, situado en la frontera con Argentina, se notificó por primera vez la presencia de pacientes con úlceras en las partes descubiertas de la piel, cuyas características clínicas y epidemiológicas correspondían a leishmaniasis. Objetivo. Describir y comprobar la presencia de leishmaniasis en Tarija, sexto departamento endémico en Bolivia. Materiales y métodos. Se hizo un estudio del brote (noviembre de 1998 a diciembre de 2002) y un estudio longitudinal (1997 a 2018) en humanos; además, se capturaron Phlebotominae y potenciales reservorios. Resultados. Se registraron 1.250 pacientes de leishmaniasis; 190 y 249 casos, en los brotes de 1998 y 2002, respectivamente, con periodos interepidémicos de 37 casos como promedio anual. El 68 % de los enfermos eran pobladores migrantes del altiplano asentados en viviendas precarias cercanas al bosque residual; el sexo predominante fue el masculino (2/1). El grupo etario económicamente activo (15 a 49 años) fue el más afectado (363/584, 62 %). Hubo 124/584 (21 %) menores de 15 años, 33/584 de menos de cuatro años. En 51/584 (8,7 %) pacientes se presentaron lesiones mucosas. Se aisló y caracterizó Leishmania (V.) braziliensis de úlceras mucosas de perros enfermos y se capturó abundantemente la especie antropofílica Nyssomyia neivai, incriminada como probable vector. Conclusiones. En 1997 se comprobó por primera vez la presencia de leishmaniasis tegumentaria en el municipio de Bermejo y, en el 2018, ya se había extendido a cuatro municipios: Padcaya, Caraparí, Entre Ríos y Yacuiba, en dirección noreste del departamento de Tarija.

Introduction: In the department of Tarija in the Bolivian-Argentine border, human cases with ulcers on uncovered parts of the skin plus clinical and epidemiological characteristics related to leishmaniasis were reported for the first time in 1997. Objective: To describe and to verify the presence of leishmaniasis in Tarija, sixth endemic department in Bolivia. Materials and methods: We conducted both an outbreak study (November, 1998, to December, 2002) and a longitudinal study (1997 to 2018) in humans, as well as captures of Phlebotominae and potential reservoirs. Results: A total of 1,250 patients were registered; in the outbreaks, 190 (1998) to 249 cases (2002) were reported and inter-epidemic periods with 37 cases as an annual average; 68% of the patients were highland migrants who inhabited precarious housing near residual forests. The predominant sex was male (ratio 2:1); the most affected group (363/584 cases, 62%) was the economically active (15 to 49 years old); 124/584 cases (21%) were children under 15 years old, 33/584 of them were under 4 years old; 51 patients/584 (8.7%) had mucosal lesions. Leishmania (V.) braziliensis was isolated and characterized from mucous ulcers of sick dogs. Nyssomyia neivai, an abundant anthropophilic species incriminated as a probable vector, was captured. Conclusions: The initial 1997 leishmaniosis presence in the municipality of Bermejo had spread out over four municipalities in 2018 (Padcaya, Caraparí, Entre Ríos, and Yacuiba), northeast of the department of Tarija.

The heterologous expression of Escherichia coli MutT enzyme is involved in the protection against oxidative stress in Leishmania braziliensis

BACKGROUND Oxidative stress is responsible for generating DNA lesions and the 8-oxoguanine (8-oxoG) is the most commonly lesion found in DNA damage. When this base is incorporated during DNA replication, it could generate double-strand DNA breaks and cellular death. MutT enzyme hydrolyzes the 8-oxoG from the nucleotide pool, preventing its incorporation during DNA replication. OBJECTIVES To investigate the importance of 8-oxoG in Leishmania infantum and L. braziliensis, in this study we analysed the impact of heterologous expression of Escherichia coli MutT (EcMutT) enzyme in drug-resistance phenotype and defense against oxidative stress. METHODS Comparative analysis of L. braziliensis and L. infantum H2O2 tolerance and cell cycle profile were performed. Lines of L. braziliensis and L. infantum expressing EcMutT were generated and evaluated using susceptibility tests to H2O2 and SbIII, cell cycle analysis, γH2A western blotting, and BrdU native detection assay. FINDINGS Comparative analysis of tolerance to oxidative stress generated by H2O2 showed that L. infantum is more tolerant to exogenous H2O2 than L. braziliensis. In addition, cell cycle analysis showed that L. infantum, after treatment with H2O2, remains in G1 phase, returning to its normal growth rate after 72 h. In contrast, after treatment with H2O2, L. braziliensis parasites continue to move to the next stages of the cell cycle. Expression of the E. coli MutT gene in L. braziliensis and L. infantum does not interfere in parasite growth or in susceptibility to SbIII. Interestingly, we observed that L. braziliensis EcMutT-expressing clones were more tolerant to H2O2 treatment, presented lower activation of γH2A, a biomarker of genotoxic stress, and lower replication stress than its parental non-transfected parasites. In contrast, the EcMutT is not involved in protection against oxidative stress generated by H2O2 in L. infantum. MAIN CONCLUSIONS Our results showed that 8-oxoG clearance in L. braziliensis is important to avoid misincorporation during DNA replication after oxidative stress generated by H2O2.

Minor temperature shifts do not affect chromosomal ploidy but cause transcriptomic changes in Leishmania braziliensis promastigotes in vitro

BACKGROUND The leishmaniases are complex neglected diseases caused by protozoan parasites of the genus Leishmania. Leishmania braziliensis is the main etiological agent of cutaneous leishmaniasis in the New World. In recent studies, genomic changes such as chromosome and gene copy number variations (CNVs), as well as transcriptomic changes have been highlighted as mechanisms used by Leishmania species to adapt to stress situations. OBJECTIVES The aim of this study was to determine the effect of short-term minor temperature shifts in the genomic and transcriptomic responses of L. braziliensis promastigotes in vitro. METHODS Growth curves, genome and transcriptome sequencing of L. braziliensis promastigotes were conducted from cultures exposed to three different temperatures (24ºC, 28ºC and 30ºC) compared with the control temperature (26ºC). FINDINGS Our results showed a decrease in L. braziliensis proliferation at 30ºC, with around 3% of the genes showing CNVs at each temperature, and transcriptomic changes in genes encoding amastin surface-like proteins, heat shock proteins and transport proteins, which may indicate a direct response to temperature stress. MAIN CONCLUSIONS This study provides evidence that L. braziliensis promastigotes exhibit a decrease in cell density, and noticeable changes in the transcriptomic profiles. However, there were not perceptible changes at chromosome CNVs and only ~3% of the genes changed their copies in each treatment.

Serological study of feline leishmaniasis and molecular detection of Leishmania infantum and Leishmania braziliensis in cats (Felis catus) / Pesquisa sorológica da leishmaniose felina e detecção molecular de Leishmania infantum e Leishmania braziliensis em gatos (Felis catus)

Abstract Blood samples and swabs from ocular conjunctiva and mouth were obtained from 64 cats. Of 64 serum samples, 19 were positive for Leishmania antibodies by ELISA (29.80%). Eight cats were positive by PCR (12.5%) in swab samples from mouth and/or ocular mucosa. Poor kappa agreement between serological and molecular results (k = 0.16) was obtained. From five positive PCR samples one was L. braziliensis and four were L. infantum. Phylogenetic analysis performed with the five isolates of Leishmania, showed that samples of L. infantum isolated from the cats were phylogenetically close to those isolated from domestic dogs in Brazil, while the L. braziliensis is very similar to the one described in humans in Venezuela. The study demonstrated that, despite high seropositivity for Leishmania in cats living in the study region, poor agreement between serological and molecular results indicate that positive serology is not indicative of Leishmania infection in cats. Parasite DNA can be detected in ocular conjunctiva and oral swabs from cats, indicating that such samples could be used for diagnosis. Results of phylogenetic analyzes show that L. infantum circulating in Brazil is capable of infecting different hosts, demonstrating the parasite's ability to overcome the interspecies barrier.

Resumo Amostras de sangue e swabs da conjuntiva ocular e oral foram obtidas de 64 gatos. Das 64 amostras de soro, 19 foram positivas para anticorpos contra Leishmania por ELISA (29,80%). Oito gatos foram positivos por PCR (12,5%) em amostras de swab da boca e / ou mucosa ocular. Demonstrou-se baixa concordância kappa entre os resultados sorológicos e moleculares (k = 0,16). Das cinco amostras positivas para PCR, uma era L. braziliensis e quatro eram L infantum. A análise filogenética realizada com os cinco isolados de Leishmania, mostrou que amostras de L. infantum, isoladas dos gatos, eram filogeneticamente próximas às isoladas de cães domésticos do Brasil enquanto L. braziliensis era muito semelhante ao descrito em humanos na Venezuela. O estudo demonstrou que, apesar da alta soropositividade para Leishmania, em gatos que vivem na região do estudo, pouca concordância entre os resultados sorológicos e moleculares indica que a sorologia positiva não é indicativa de infecção por Leishmania em gatos. O DNA do parasita pode ser detectado na conjuntiva ocular e nas zaragatoas orais de gatos, indicando que essas amostras podem ser usadas para o diagnóstico. . Resultados de análises filogenéticas mostram que L. infantum, circulando no Brasil, é capaz de infectar diferentes hospedeiros, demonstrando a capacidade do parasita de superar a barreira interespécies.

Sandflies in an endemic area for Visceral Leishmaniasis in Northeastern Brazil / Flebotomíneos em uma área endêmica para Leishmaniose Visceral no Nordeste do Brasil

Abstract Phlebotomines of the genus Lutzomyia are important vector for species of Leishmania, the etiological agent of leishmaniasis. The aim of this study was to assess the diversity of sandflies in an endemic area for Visceral Leishmaniasis (VL). Sampling was performed in four localities on the coast of the municipality of Goiana, state of Pernambuco, Northeastern Brazil. Specimens were collected monthly on three consecutive nights, from November 2017 to October 2018. CDC light traps were installed at a height of 1.5 m above the ground, in two ecotypes (i.e. tree and animal facility), both in peridomestic areas. A total of 5,205 sandflies were collected, among which the species Lutzomyia longipalpis (99.85%; 5,197/5,205) was the most common, followed by Lutzomyia evandroi (0.13%; 07/5,205) and Lutzomyia whitmani (0.02%; 01/5,205). Specimens of L. longipalpis were collected throughout the study period and most of them were found near to the animal facilities. The findings from this research indicate that vectors for Leishmania infantum are present in the study area throughout the year, along with occurrences of vectors relating to Cutaneous Leishmaniasis (CL). Preventive vector control measures need to be implemented in Goiana to reduce the risk of infection for the human and animal populations.

Resumo Flebotomíneos do gênero Lutzomyia são importantes vetores de espécies de Leishmania, agente etiológico das leishmanioses. O objetivo deste estudo foi avaliar a diversidade de flebotomíneos em área endêmica para Leishmaniose Visceral (LV). As coletas foram realizadas em quatro localidades do litoral do município de Goiana, Pernambuco, Nordeste do Brasil. Os espécimes foram coletados mensalmente em três noites consecutivas de novembro de 2017 a outubro de 2018. Foram instaladas armadilhas luminosas modelo CDC a uma altura de 1,5 m acima do solo em dois ecótopos (ex. árvore e instalações de animais), ambos em áreas peridomiciliares. Um total de 5.205 flebotomíneos foi coletado, sendo Lutzomyia longipalpis (99,85%; 5.197/5.205) a mais comum, seguida por Lutzomyia evandroi (0,13%; 07/5.205) e Lutzomyia whitmani (0,02%; 01/5.205). L. longipalpis foi coletada durante todo o período do estudo. A maioria dos espécimes foi detectada perto das instalações dos animais. Os achados deste estudo indicam a presença de vetores de Leishmania infantum na área avaliada ao longo do ano, bem como a ocorrência de vetores relacionados à Leishmaniose Cutânea (LC). Medidas preventivas de controle vetorial devem ser implementadas em Goiana para reduzir o risco de infecção à população humana e animal.

Leishmaniose Tegumentar Americana: uma análise histopatológica e molecular em lesões de dermatites no estado de Pernambuco, Brasil / American Cutaneous Leishmaniasis: a histopathological and molecular analysis of dermatitis lesions in the State of Pernambuco, Brazil

Objetivo: Realizar uma análise histopatológica e molecular em biópsia de pele entre as lesões de dermatites de pacientes com suspeita de Leishmaniose Tegumentar Americana (LTA) no hospital de referência do estado de Pernambuco entre o período de 2016 e 2017. Métodos: Trata-se de um estudo descritivo observacional, no qual todos os pacientes com lesões clinicamente sugestivas para LTA incluídos no estudo foram submetidos à coleta de biópsia de pele das lesões, as quais foram analisadas pela técnica histopatológica e PCR (Reação em Cadeia de Polimerase). Resultados: Foram analisadas 24 amostras de biópsia de pele de pacientes com suspeita clínica de LTA, por testes histopatológicos e confirmação pela PCR. As amostras foram caracterizadas pela busca do DNA de Leishmania braziliensis através da PCR. Das 24 amostras estudadas, em nenhuma foi encontrado DNA de L. braziliensis. Apenas em um caso foi detectada presença de amastigotas de Leishmania pela técnica histopatológica. Outros achados microscópicos observados foram: dermatite granulomatosa (33,33%), úlcera crônica (20,83%), carcinoma basocelular (16,66%), Leishmaniose, dermatite plasmocitária e inflamação granulomatosa (8,33%) e Hanseníase (4,16%). Conclusão: O diagnóstico histopatológico detectou um caso de LTA, porém, a PCR não encontrou DNA do parasito. A análise histopatológica mostrou que as lesões dermatotrópicas dos pacientes são oriundas principalmente de úlceras, tumores de pele e hanseníase.

Objective: Accomplish a histopathological and molecular analysis in skin biopsy between the dermatitis lesions of patients with suspected American Cutaneous Leishmaniasis (ATL) at the Hospital of Reference of the State of Pernambuco between the period of 2016 and 2017. Methods: This is a descriptive, observational study in which all patients with clinically suggestive lesions for ATL included in the study were submitted to skin biopsy of the lesions and analyzed by the histopathological technique and PCR (Polymerase Chain Reaction). Results: Were analyzed 24 skin biopsy samples from patients with clinical suspicion of ATL, by histopathological tests and confirmation by PCR. Samples were characterized by the search of Leishmania braziliensis DNA through PCR. Of the 24 samples studied, no DNA of L. braziliensis was found. Only in one case was detected presence of Leishmania amastigotes by histopathological technique. Other microscopic findings were granulomatous dermatitis (33.33%), chronic ulcer (20.83%), basal cell carcinoma (16.66%), Leishmaniasis, plasmacytoma dermatitis and granulomatous inflammation (8.33%) and leprosy, 16%). Conclusion: The histopathological diagnosis detected a case of ATL, however, the PCR did not find DNA of the parasite. The histopathological analysis showed that the dermatotropic lesions of the patients come mainly from ulcers, skin tumors and leprosy.

Disseminated leishmaniasis: clinical, pathogenic, and therapeutic aspects

Abstract: Disseminated leishmaniasis is a severe and emerging form of American tegumentary leishmaniasis. Disseminated leishmaniasis is defined by the presence of more than 10 polymorphic cutaneous lesions, distributed over more than two noncontiguous parts of the body. Nasal mucosal involvement is observed in almost half of cases. Disseminated leishmaniasis patients present with a decreased production of Th1 cytokines in the peripheral blood due to the attraction of leishmania- activated T cells to the multiple cutaneous lesions. Disseminated leishmaniasis development is poorly understood and is related to a complex network involving environmental, host immune response, and parasite factors, in which L. braziliensis polymorphism plays an important role. Disseminated leishmaniasis is a challenging disease to cure, presenting a high failure rate of 75% to pentavalent antimony therapy. Despite its importance and severity, this form of American tegumentary leishmaniasis has been poorly studied and documented, deserving greater attention from professionals working in endemic areas.

Antimony resistance in Leishmania (Viannia) braziliensis clinical isolates from atypical lesions associates with increased ARM56/ARM58 transcripts and reduced drug uptake

BACKGROUND In addition to the limited therapeutic arsenal and the side effects of antileishmanial agents, drug resistance hinders disease control. In Brazil, Leishmania braziliensis causes atypical (AT) tegumentary leishmaniasis lesions, frequently refractory to treatment. OBJECTIVES The main goal of this study was to characterise antimony (Sb)-resistant (SbR) L. braziliensis strains obtained from patients living in Xakriabá indigenous community, Minas Gerais, Brazil. METHODS The aquaglyceroporin 1-encoding gene (AQP1) from L. braziliensis clinical isolates was sequenced, and its function was evaluated by hypo-osmotic shock. mRNA levels of genes associated with Sb resistance were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Atomic absorption was used to measure Sb uptake. FINDINGS Although clinical isolates presented delayed recovery time in hypo-osmotic shock, AQP1 function was maintained. Isolate 340 accumulated less Sb than all other isolates, supporting the 65-fold downregulation of AQP1 mRNA levels. Both 330 and 340 isolates upregulated antimony resistance marker (ARM) 56/ARM58 and multidrug resistant protein A (MRPA); however, only ARM58 upregulation was an exclusive feature of SbR field isolates. CA7AE seemed to increase drug uptake in L. braziliensis and represented a tool to study the role of glycoconjugates in Sb transport. MAIN CONCLUSIONS There is a clear correlation between ARM56/58 upregulation and Sb resistance in AT-harbouring patients, suggesting the use of these markers as potential indicators to help the treatment choice and outcome, preventing therapeutic failure.

Protein-protein interactions of the nicotinamide/nicotinate mononucleotide adenylyltransferase of Leishmania braziliensis

BACKGROUND Nicotinamide adenine dinucleotide (NAD) plays a central role in energy metabolism and integrates cellular metabolism with signalling and gene expression. NAD biosynthesis depends on the enzyme nicotinamide/nicotinate mononucleotide adenylyltransferase (NMNAT; EC: 2.7.7.1/18), in which converge the de novo and salvage pathways. OBJECTIVE The purpose of this study was to analyse the protein-protein interactions (PPI) of NMNAT of Leishmania braziliensis (LbNMNAT) in promastigotes. METHODS Transgenic lines of L. braziliensis promastigotes were established by transfection with the pSP72αneoαLbNMNAT-GFP vector. Soluble protein extracts were prepared, co-immunoprecipitation assays were performed, and the co-immunoprecipitates were analysed by mass spectrometry. Furthermore, bioinformatics tools such as network analysis were applied to generate a PPI network. FINDINGS Proteins involved in protein folding, redox homeostasis, and translation were found to interact with the LbNMNAT protein. The PPI network indicated enzymes of the nicotinate and nicotinamide metabolic routes, as well as RNA-binding proteins, the latter being the point of convergence between our experimental and computational results. MAIN CONCLUSION We constructed a model of PPI of LbNMNAT and showed its association with proteins involved in various functions such as protein folding, redox homeostasis, translation, and NAD synthesis.

Leishmanicidal compounds of Nectria pseudotrichia, an endophytic fungus isolated from the plant Caesalpinia echinata (Brazilwood)

BACKGROUND In a screen of extracts from plants and fungi to detect antileishmanial activity, we found that the ethyl acetate extract of the fungus Nectria pseudotrichia, isolated from the tree Caesalpinia echinata (Brazilwood), is a promising source of bioactive compounds. OBJECTIVES The aims of this study were to isolate and determine the chemical structures of the compounds responsible for the antileishmanial activity of the organic extract from N. pseudotrichia. METHODS Compounds were isolated by chromatographic fractionation using semi-preparative high-performance liquid chromatography, and their chemical structures were determined by analytical and spectral data and by comparison with published data. The antileishmanial activity of the isolated compounds was evaluated in intracellular amastigote forms of Leishmania (Viannia) braziliensis expressing firefly luciferase as reporter gene, and cytotoxicity was determined in Vero and THP-1 mammalian cell lines by MTT assay. FINDINGS Fractionation of the extract yielded seven compounds: 10-acetyl trichoderonic acid A (1), 6′-acetoxy-piliformic acid (2), 5′,6′-dehydropiliformic acid (3), piliformic acid (4), hydroheptelidic acid (5), xylaric acid D (6), and cytochalasin D (7). Compounds 1, 2 and 3 are reported here for the first time. Compounds 1, 2, and 5 were more active, with IC50 values of 21.4, 28.3, and 24.8 µM, respectively, and showed low toxicity to Vero and THP-1 cells. MAIN CONCLUSIONS N. pseudotrichia produces secondary metabolites that are more toxic to intracellular amastigote forms of L. (V.) braziliensis than to mammalian cells.