Bioluminescent Imaging Identifies Thymus, As Overlooked Colonized Organ, in a Chronic Model of Leishmania donovani Mouse Visceral Leishmaniasis

Background: Visceral leishmaniasis is a vector-borne disease caused by Leishmania donovani transmitted by sand fly species. It is the third most common vector-borne disease globally. Visceral leishmaniasis is endemic in Ethiopia with an estimated annual incidence ranging from 3700 to 7400 cases. This research aimed to assess the clinical presentations and laboratory profiles of visceral leishmaniasis for early diagnosis and timely initiation of management. Objective: To describe the clinical and laboratory manifestation and diagnostic modalities of visceral leishmaniasis among adult patients admitted to Felege Hiwot Hospital, from 1 September 2016 to 30 August 2019. Method: Institution-based retrospective cross-sectional study was conducted among 141 patients admitted to Felege Hiwot Hospital from 1 September 2016 to 30 August 2019. Descriptive statistics were used to describe the clinical presentation and laboratory profiles of patients with visceral leishmaniasis. Results: Among a total of 141 enrolled patients in the study, males were affected 13-fold. Most of them were travelers to endemic areas during the winter season for labor work. The mean duration of illness was 48 days. Common symptoms were fever (96.5%), weightless (82.5%), jaundice (18.4%), vomiting/diarrhea (13.5%), and bleeding episodes (11.3%). Splenomegaly was seen in 98.6%, ascites in 35.5%, and lymphadenopathy in 9.9%. Lymphadenopathy was seen significantly in HIV patients (40%). Anemia was seen in 95%, thrombocytopenia in 90.2%, leukopenia in 86.4%, and pancytopenia in 79.4%. Half of the patients had coinfection. Neutropenic sepsis was seen in 21.3%. The diagnosis was made by tissue aspiration in 65% of patients. Conclusion: The majority of patients who were diagnosed to have visceral leishmaniasis were young male adults who traveled to the endemic areas seasonally. Fever and splenomegaly were seen as the commonest clinical presentation. Lymphadenopathy occurred in high frequency among HIV co-infected patients. Anemia was the commonest hematologic finding.

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A novel recombinant Leishmania donovani p45, a partial coding region of methionine aminopeptidase, generates protective immunity by inducing a Th1 stimulatory response against experimental visceral leishmaniasis

International Journal for Parasitology ◽

10.1016/j.ijpara.2012.02.013 ◽

2012 ◽

Vol 42 (5) ◽

pp. 429-435 ◽

Cited By ~ 20

Author(s):

Reema Gupta ◽

Pramod K. Kushawaha ◽

Chandra Dev Pati Tripathi ◽

Shyam Sundar ◽

Anuradha Dube

Keyword(s):

Visceral Leishmaniasis ◽

Protective Immunity ◽

Leishmania Donovani ◽

Methionine Aminopeptidase ◽

Coding Region

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Hemophagocytosis in Experimental Visceral Leishmaniasis by Leishmania donovani

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0004505 ◽

2016 ◽

Vol 10 (3) ◽

pp. e0004505 ◽

Cited By ~ 8

Author(s):

Ayako Morimoto ◽

Satoko Omachi ◽

Yasutaka Osada ◽

James K. Chambers ◽

Kazuyuki Uchida ◽

...

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Donovani

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Diagnosis and Causative Species of Visceral Leishmaniasis in Southwest Saudi Arabia

American Journal of Tropical Medicine and Hygiene ◽

10.4269/ajtmh.20-1006 ◽

2021 ◽

Author(s):

Aymen Abdelhaleem ◽

Nabil Dhayhi ◽

Mohamed Salih Mahfouz ◽

Ommer Daffalla ◽

Mansour Mubarki ◽

...

Keyword(s):

Saudi Arabia ◽

Visceral Leishmaniasis ◽

Real Time ◽

Real Time Pcr ◽

Leishmania Donovani ◽

Target Genes ◽

Sample Volume ◽

Pcr Products ◽

Polymerase Chain ◽

Robust Evidence

Visceral leishmaniasis (VL) is the most severe clinical form of the disease and has been reported in the Jazan region of southwest Saudi Arabia. This study aimed to diagnose VL by real-time polymerase chain reaction (PCR) and the direct agglutination test (DAT) and to identify the causative Leishmania species. A total of 80 participants, including 30 suspected VL patients, 30 healthy endemic control individuals, and 20 malaria disease controls, were enrolled in this study. Blood samples were collected and tested for Leishmania DNA by real-time PCR and for antibody by the DAT. Sequencing of some amplified PCR products was used to identify the causative Leishmania species. The diagnosis of VL was successfully achieved by both real-time PCR and by DAT with 100% sensitivity. Leishmania donovani and Leishmania infantum species were detected by sequencing both by the kDNA and ITS1 target genes, followed a BLASTn search. The detection of VL antibody by the DAT followed by the confirmatory detection of Leishmania DNA in patient blood by PCR could promote the adoption of the much less invasive and more sensitive methods for the routine diagnosis of VL. Further study with high sample volume to evaluate the PCR and the DAT are needed, to generate more robust evidence. Based on the sequencing results, emerging studies on VL should focus on the causative Leishmania species, reservoirs, and vectors that are important in the study area.

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Genetic Validation of Leishmania donovani Lysyl-tRNA Synthetase Shows that It Is Indispensable for Parasite Growth and Infectivity

mSphere ◽

10.1128/mspheredirect.00340-17 ◽

2017 ◽

Vol 2 (4) ◽

Author(s):

Sanya Chadha ◽

N. Arjunreddy Mallampudi ◽

Debendra K. Mohapatra ◽

Rentala Madhubala

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Donovani ◽

Essential Gene ◽

Protozoan Parasite ◽

Protein Translation ◽

Trna Synthetase ◽

Parasite Growth ◽

Coding Sequences ◽

Trna Synthetases ◽

Aminoacyl Trna Synthetases

ABSTRACT Leishmania donovani is a protozoan parasite that causes visceral leishmaniasis. Increasing resistance and severe side effects of existing drugs have led to the need to identify new chemotherapeutic targets. Aminoacyl-tRNA synthetases (aaRSs) are ubiquitous and are required for protein synthesis. aaRSs are known drug targets for bacterial and fungal pathogens. Here, we have characterized and evaluated the essentiality of L. donovani lysyl-tRNA synthetase (LdLysRS). Two different coding sequences for lysyl-tRNA synthetases are annotated in the Leishmania genome database. LdLysRS-1 (LdBPK_150270.1), located on chromosome 15, is closer to apicomplexans and eukaryotes, whereas LdLysRS-2 (LdBPK_300130.1), present on chromosome 30, is closer to bacteria. In the present study, we have characterized LdLysRS-1. Recombinant LdLysRS-1 displayed aminoacylation activity, and the protein localized to the cytosol. The LdLysRS-1 heterozygous mutants had a restrictive growth phenotype and attenuated infectivity. LdLysRS-1 appears to be an essential gene, as a chromosomal knockout of LdLysRS-1 could be generated when the gene was provided on a rescuing plasmid. Cladosporin, a fungal secondary metabolite and a known inhibitor of LysRS, was more potent against promastigotes (50% inhibitory concentration [IC50], 4.19 µM) and intracellular amastigotes (IC50, 1.09 µM) than were isomers of cladosporin (3-epi-isocladosporin and isocladosporin). These compounds exhibited low toxicity to mammalian cells. The specificity of inhibition of parasite growth caused by these inhibitors was further assessed using LdLysRS-1 heterozygous mutant strains and rescue mutant promastigotes. These inhibitors inhibited the aminoacylation activity of recombinant LdLysRS. Our data provide a framework for the development of a new class of drugs against this parasite. IMPORTANCE Aminoacyl-tRNA synthetases are housekeeping enzymes essential for protein translation, providing charged tRNAs for the proper construction of peptide chains. These enzymes provide raw materials for protein translation and also ensure fidelity of translation. L. donovani is a protozoan parasite that causes visceral leishmaniasis. It is a continuously proliferating parasite that depends heavily on efficient protein translation. Lysyl-tRNA synthetase is one of the aaRSs which charges lysine to its cognate tRNA. Two different coding sequences for lysyl-tRNA synthetases (LdLysRS) are present in this parasite. LdLysRS-1 is closer to apicomplexans and eukaryotes, whereas LdLysRS-2 is closer to bacteria. Here, we have characterized LdLysRS-1 of L. donovani. LdLysRS-1 appears to be an essential gene, as the chromosomal null mutants did not survive. The heterozygous mutants showed slower growth kinetics and exhibited attenuated virulence. This study also provides a platform to explore LdLysRS-1 as a potential drug target.

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Distinct Roles for CD4+ Foxp3+ Regulatory T Cells and IL-10–Mediated Immunoregulatory Mechanisms during Experimental Visceral Leishmaniasis Caused by Leishmania donovani

The Journal of Immunology ◽

10.4049/jimmunol.1701582 ◽

2018 ◽

Vol 201 (11) ◽

pp. 3362-3372 ◽

Cited By ~ 10

Author(s):

Patrick T. Bunn ◽

Marcela Montes de Oca ◽

Fabian de Labastida Rivera ◽

Rajiv Kumar ◽

Susanna S. Ng ◽

...

Keyword(s):

T Cells ◽

Visceral Leishmaniasis ◽

Regulatory T Cells ◽

Leishmania Donovani ◽

Immunoregulatory Mechanisms

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Genomic and phenotypic characterization of experimentally selected resistant Leishmania donovani reveals a role for dynamin-1 like protein in the mechanism of resistance to a novel anti-leishmanial compound

10.1101/2021.01.05.425522 ◽

2021 ◽

Author(s):

Aya Hefnawy ◽

Gabriel Negreira ◽

Marlene Jara ◽

James A. Cotton ◽

Ilse Maes ◽

...

Keyword(s):

Drug Resistance ◽

Visceral Leishmaniasis ◽

Infectious Diseases ◽

Leishmania Donovani ◽

Neglected Tropical Diseases ◽

Arms Race ◽

Etiological Agent ◽

Phenotypic Characterization ◽

Tropical Diseases

AbstractThe implementation of prospective drug resistance (DR) studies in the R&D pipelines is a common practice for many infectious diseases, but not for Neglected Tropical Diseases. Here, we explored and demonstrated the importance of this approach, using as paradigms Leishmania donovani, the etiological agent of Visceral Leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK ‘Leishbox’ to treat VL. We experimentally selected resistance to TCMDC-143345 in vitro and characterized resistant parasites at genomic and phenotypic levels. We found that it took more time to develop resistance to TCMDC-143345 than to other drugs in clinical use and that there was no cross resistance to these drugs, suggesting a new and unique mechanism. By whole genome sequencing, we found two mutations in the gene encoding the L. donovani dynamin-1-like protein (LdoDLP1) that were fixed at highest drug pressure. Through phylogenetic analysis, we identified LdoDLP1 as a family member of the dynamin-related proteins, a group of proteins that impacts the shapes of biological membranes by mediating fusion and fission events, with a putative role in mitochondrial fission. We found that L. donovani lines genetically engineered to harbor the two identified LdoDLP1 mutations were resistant to TCMDC-143345 and displayed altered mitochondrial properties. By homology modeling, we showed how the two LdoDLP1 mutations may influence protein structure and function. Taken together, our data reveal a clear involvement of LdoDLP1 in the adaptation/resistance of L. donovani to TCMDC-143345.ImportanceHumans and their pathogens are continuously locked in a molecular arms race during which the eventual emergence of pathogen drug resistance (DR) seems inevitable. For neglected tropical diseases (NTDs), DR is generally studied retrospectively, once it has already been established in clinical settings. We previously recommended to keep one step ahead in the host-pathogen arms race and implement prospective DR studies in the R&D pipeline, a common practice for many infectious diseases, but not for NTDs. Here, using Leishmania donovani, the etiological agent of Visceral Leishmaniasis (VL), and TCMDC-143345, a promising compound of the GSK ‘Leishbox’ to treat VL, as paradigms, we experimentally selected resistance to the compound and proceeded to genomic and phenotypic characterization of DR parasites. The results gathered in the present study suggest a new DR mechanism involving the L. donovani dynamin-1 like protein (LdoDLP1) and demonstrate the practical relevance of prospective DR studies.

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