Identification of antimony resistance markers in Leishmania tropica field isolates through a cDNA-AFLP approach

ABSTRACT Indian Leishmania donovani isolates (n = 19) from regional zones representing various levels of antimony resistance displayed significantly (P < 0.01) correlated results with respect to in vitro susceptibility to the antileishmanial drugs sodium antimony gluconate, amphotericin B, and Miltefosine, raising the possibility of cross-resistance mechanisms operating in the field isolates. The results of gene expression analysis of LdMT and LdRos3 were suggestive of alternate mechanisms of Miltefosine susceptibility in the isolates.

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A Telomeric Cluster of Antimony Resistance Genes on Chromosome 34 of Leishmania infantum

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00544-16 ◽

2016 ◽

Vol 60 (9) ◽

pp. 5262-5275 ◽

Cited By ~ 13

Author(s):

Paloma Tejera Nevado ◽

Eugenia Bifeld ◽

Katharina Höhn ◽

Joachim Clos

Keyword(s):

Gene Cluster ◽

Selective Advantage ◽

Marker Genes ◽

Leishmania Braziliensis ◽

Multidrug Resistance Gene ◽

Content Type ◽

Intracellular Amastigotes ◽

Antimony Resistance ◽

Resistance Markers ◽

Generation Sequencing

ABSTRACTThe mechanisms underlying the drug resistance ofLeishmaniaspp. are manifold and not completely identified. Apart from the highly conserved multidrug resistance gene family known from higher eukaryotes,Leishmaniaspp. also possess genus-specific resistance marker genes. One of them, ARM58, was first identified inLeishmania braziliensisusing a functional cloning approach, and its domain structure was characterized inL. infantum. Here we report thatL. infantumARM58 is part of a gene cluster at the telomeric end of chromosome 34 also comprising the neighboring genes ARM56 and HSP23. We show that overexpression of all three genes can confer antimony resistance to intracellular amastigotes. Upon overexpression inL. donovani, ARM58 and ARM56 are secreted via exosomes, suggesting a scavenger/secretion mechanism of action. Using a combination of functional cloning and next-generation sequencing, we found that the gene cluster was selected only under antimonyl tartrate challenge and weakly under Cu2+challenge but not under sodium arsenite, Cd2+, or miltefosine challenge. The selective advantage is less pronounced in intracellular amastigotes treated with the sodium stibogluconate, possibly due to the known macrophage-stimulatory activity of this drug, against which these resistance markers may not be active. Our data point to the specificity of these three genes for antimony resistance.

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Downregulation of Mitogen-Activated Protein Kinase 1 of Leishmania donovani Field Isolates Is Associated with Antimony Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00736-11 ◽

2011 ◽

Vol 56 (1) ◽

pp. 518-525 ◽

Cited By ~ 25

Author(s):

Ashutosh ◽

Mansi Garg ◽

Shyam Sundar ◽

Robert Duncan ◽

Hira L. Nakhasi ◽

...

Keyword(s):

Protein Kinase ◽

Leishmania Donovani ◽

Indian Subcontinent ◽

Field Isolate ◽

Laboratory Strain ◽

Mitogen Activated Protein Kinase ◽

Content Type ◽

Field Isolates ◽

Mitogen Activated Protein ◽

Antimony Resistance

ABSTRACTEmergence of resistance to pentavalent antimonials has become a severe obstacle in the treatment of visceral leishmaniasis (VL) on the Indian subcontinent. The mechanisms operating in laboratory-generated strains are somewhat known, but the determinants of clinical antimony resistance are not well understood. By utilizing a DNA microarray expression profiling approach, we identified a gene encoding mitogen-activated protein kinase 1 (MAPK1) for the kinetoplast protozoanLeishmania donovani(LdMAPK1) that was consistently downregulated in antimony-resistant field isolates. The expression level of the gene was validated by real-time PCR. Furthermore, decreased expression of LdMAPK1 was also confirmed at the protein level in resistant isolates. Primary structure analysis of LdMAPK1 revealed the presence of all of the characteristic features of MAPK1. When expressed inEscherichia coli, the recombinant enzyme showed kinase activity with myelin basic protein as the substrate and was inhibited by staurosporine. Interestingly, overexpression of this gene in a drug-sensitive laboratory strain and a resistant field isolate resulted in increased the sensitivity of the transfectants to potassium antimony tartrate, suggesting that it has a role in antimony resistance. Our results demonstrate that downregulation of LdMAPK1 may be in part correlated with antimony drug resistance in Indian VL isolates.

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New Cryptic Species of Phlebotomus Illustrating the Paradigm Shift of the Species Concept, with Evaluation of Their Taxonomic Status and Their Roles as Vectors of Leishmania tropica in North Africa

Entomological News ◽

10.3157/021.128.0409 ◽

2019 ◽

Vol 128 (4) ◽

pp. 365

Author(s):

Ahmed Tabbabi

Keyword(s):

Cryptic Species ◽

North Africa ◽

Paradigm Shift ◽

Species Concept ◽

Taxonomic Status ◽

Leishmania Tropica

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Leishmanicidal Activity of Plant Extracts from Sefrou, a Moroccan Focus of Leishmaniasis, against Various Leishmania Parasites in the Promastigote Stage

Phytothérapie ◽

10.3166/phyto-2018-0085 ◽

2018 ◽

Vol 17 (2) ◽

pp. 83-89 ◽

Cited By ~ 1

Author(s):

I. Zeouk ◽

A. Et-Touys ◽

M. Balouiri ◽

H. Fellah ◽

A. El Ouali Lalami ◽

...

Keyword(s):

Cutaneous Leishmaniasis ◽

Plant Extracts ◽

Leishmania Infantum ◽

Leishmania Major ◽

Local Population ◽

Public Health Problem ◽

World Health ◽

Total Phenolic ◽

Leishmania Tropica ◽

Cistus Salviifolius

According to the World Health Organization, leishmaniasis remains a major worldwide public health problem. The province of Sefrou located in the center of Morocco is a focus of cutaneous leishmaniasis. The present study aims at evaluating the antileishmanial potential of Berberis sp.,Crataegus oxyacantha, Cistus salviifolius, Ephedra altissima and Lavandula dentatafrequently used by the local population. Methanolic extracts were tested against the promastigote form ofLeishmania tropica, Leishmania majorandLeishmania infantumusing tetrazolium-based colorimetric (MTT) assay. The total phenol and flavonoids content of all extracts were determined using the Folin–Ciocalteu reagent, aluminum chloride, and potassium acetate solutions respectively. The plant extracts exhibited antileishmanial activity with variability depending on the tested strain and the plant species compared to Glucantime® used as control (IC50 (the half maximal inhibitory concentration) > 1,000 μg/mL). The best inhibition was observed with Berberis sp., againstLeishmania major(IC50 = 394.40 ± 3.02 μg/ml), andEphedra altissima(reported for the first time) againstLeishmania infantum(IC50 = 490.84 ± 3.15 μg/mL).Leishmania tropicahas shown the same sensitivity behavior toward the five extracts (in average IC50 = 540 ± 11.20 μg/mL). The total phenolic content was higher forCrataegus oxyacanthaandCistus salviifolius(140.67 ± 3.17 μg eq Gallic Acid (GA)/ mg of Extract (E) and 133.83 ± 9.03 μg eq GA/mg of E respectively), while flavonoid was higher forCistus salviifoliusandLavandula dentata(57.92 ± 2.46 μg eq Quercetin (Que)/ mg of Extract (E) and 41.53 ± 1.74 μg eq Que/mg of E). All the tested extracts present some promising aspects that may cure cutaneous leishmaniasis in the center of Morocco; further bioguided assays are needed to isolate the fractions and the bioactive molecule.

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