scholarly journals Evaluation of α,β-Unsaturated Ketones as Antileishmanial Agents

2015 ◽  
Vol 59 (6) ◽  
pp. 3598-3601 ◽  
Author(s):  
Miguel A. Vasquez ◽  
Eva Iniguez ◽  
Umashankar Das ◽  
Stephen M. Beverley ◽  
Linda J. Herrera ◽  
...  
Keyword(s):  
Murine Model ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Effective Concentration ◽  
Bioluminescent Imaging ◽  
Content Type ◽  
Unsaturated Ketones ◽  
Parasite Replication ◽  
20 Nm

ABSTRACTIn this study, we assessed the antileishmanial activity of 126 α,β-unsaturated ketones. The compounds NC901, NC884, and NC2459 showed high leishmanicidal activity for both the extracellular (50% effective concentration [EC50], 456 nM, 1,122 nM, and 20 nM, respectively) and intracellular (EC50, 1,870 nM, 937 nM, and 625 nM, respectively) forms ofLeishmania majorpropagated in macrophages, with little or no toxicity to mammalian cells. Bioluminescent imaging of parasite replication showed that all three compounds reduced the parasite burden in the murine model, with no apparent toxicity.

scholarly journals Zinc(II)-Dipicolylamine Coordination Complexes as Targeting and Chemotherapeutic Agents for Leishmania major

2016 ◽  
Vol 60 (5) ◽  
pp. 2932-2940 ◽  
Author(s):  
Douglas R. Rice ◽  
Paola Vacchina ◽  
Brianna Norris-Mullins ◽  
Miguel A. Morales ◽  
Bradley D. Smith
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Coordination Complexes ◽  
Chemotherapeutic Agents ◽  
Selective Toxicity ◽  
Content Type

ABSTRACTCutaneous leishmaniasis is a neglected tropical disease that causes painful lesions and severe disfigurement. Modern treatment relies on a few chemotherapeutics with serious limitations, and there is a need for more effective alternatives. This study describes the selective targeting of zinc(II)-dipicolylamine (ZnDPA) coordination complexes towardLeishmania major, one of the species responsible for cutaneous leishmaniasis. Fluorescence microscopy ofL. majorpromastigotes treated with a fluorescently labeled ZnDPA probe indicated rapid accumulation of the probe within the axenic promastigote cytosol. The antileishmanial activities of eight ZnDPA complexes were measured using anin vitroassay. All tested complexes exhibited selective toxicity againstL. majoraxenic promastigotes, with 50% effective concentration values in the range of 12.7 to 0.3 μM. Similar toxicity was observed against intracellular amastigotes, but there was almost no effect on the viability of mammalian cells, including mouse peritoneal macrophages.In vivotreatment efficacy studies used fluorescence imaging to noninvasively monitor changes in the red fluorescence produced by an infection of mCherry-L. majorin a mouse model. A ZnDPA treatment regimen reduced the parasite burden nearly as well as the reference care agent, potassium antimony(III) tartrate, and with less necrosis in the local host tissue. The results demonstrate that ZnDPA coordination complexes are a promising new class of antileishmanial agents with potential for clinical translation.

scholarly journals Identification of Metal Dithiocarbamates as a Novel Class of Antileishmanial Agents

2015 ◽  
Vol 59 (4) ◽  
pp. 2144-2152 ◽  
Author(s):  
Dhiman Sankar Pal ◽  
Dipon Kumar Mondal ◽  
Rupak Datta
Keyword(s):  
Mammalian Cells ◽  
Leishmania Major ◽  
Lethal Dose ◽  
Parasite Burden ◽  
Intracellular Acidosis ◽  
Content Type ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Metal Dithiocarbamates ◽  
Morphological Deformities

ABSTRACTDithiocarbamates have emerged as potent carbonic anhydrase (CA) inhibitors in recent years. Given that CAs are important players in cellular metabolism, the objective of this work was to exploit the CA-inhibitory property of dithiocarbamates as a chemotherapeutic weapon against theLeishmaniaparasite. We report here strong antileishmanial activity of three hitherto unexplored metal dithiocarbamates, maneb, zineb, and propineb. They inhibited CA activity inLeishmania majorpromastigotes at submicromolar concentrations and resulted in a dose-dependent inhibition of parasite growth. Treatment with maneb, zineb, and propineb caused morphological deformities of the parasite andLeishmaniacell death with 50% lethal dose (LD50) values of 0.56 μM, 0.61 μM, and 0.27 μM, respectively. These compounds were even more effective against parasites growing in acidic medium, in which their LD50values were severalfold lower. Intracellular acidosis leading to apoptotic and necrotic death ofL. majorpromastigotes was found to be the basis of their leishmanicidal activity. Maneb, zineb, and propineb also efficiently reduced the intracellular parasite burden, suggesting that amastigote forms of the parasite are also susceptible to these metal dithiocarbamates. Interestingly, mammalian cells were unaffected by these compounds even at concentrations which are severalfold higher than their antileishmanial LD50s). Our data thus establish maneb, zineb, and propineb as a new class of antileishmanial compounds having broad therapeutic indices.

scholarly journals Leishmania major Telomerase TERT Protein Has a Nuclear/Mitochondrial Eclipsed Distribution That Is Affected by Oxidative Stress

2014 ◽  
Vol 83 (1) ◽  
pp. 57-66 ◽  
Author(s):  
Riward Campelo ◽  
Isabel Díaz Lozano ◽  
Katherine Figarella ◽  
Antonio Osuna ◽  
José Luis Ramírez
Keyword(s):  
Oxidative Stress ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Telomerase Activity ◽  
Kinetoplast Dna ◽  
Protein Subunit ◽  
Content Type ◽  
Human Parasite ◽  
Microscopy Techniques ◽  
Parasitic Cell

In its canonical role the reverse transcriptase telomerase recovers the telomeric repeats that are lost during DNA replication. Other locations and activities have been recently described for the telomerase protein subunit TERT in mammalian cells. In the present work, using biochemistry, molecular biology, and electron microscopy techniques, we found that in the human parasiteLeishmania major, TERT (and telomerase activity) shared locations between the nuclear, mitochondrial, and cytoplasmic compartments. Also, some telomerase activity and TERT protein could be found in ∼100-nm nanovesicles. In the mitochondrial compartment, TERT appears to be mainly associated with the kinetoplast DNA. WhenLeishmaniacells were exposed to H2O2, TERT changed its relative abundance and activity between the nuclear and mitochondrial compartments, with the majority of activity residing in the mitochondrion. Finally, overexpression of TERT inLeishmaniatransfected cells not only increased the parasitic cell growth rate but also increased their resistance to oxidative stress.

Leishmanicidal potentials of Gossypium hirsutum extract and its fractions on Leishmania major in a murine model: parasite burden, gene expression, and histopathological profile

2021 ◽  
Vol 70 (6) ◽  
Author(s):  
Fatemeh Sharifi ◽  
Fariba Sharififar ◽  
Mostafa Pournamdari ◽  
Mehdi Ansari ◽  
Razieh Tavakoli Oliaee ◽  
...  
Keyword(s):  
Gene Expression ◽  
Gossypium Hirsutum ◽  
Murine Model ◽  
Complex Disease ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Control Group ◽  
Standard Drug ◽  
Soxhlet Apparatus

Introduction. Leishmaniasis is a neglected tropical and subtropical disease caused by over 20 protozoan species. Hypothesis. Treatment of this complex disease with traditional synthetic drugs is a major challenge worldwide. Natural constituents are unique candidates for future therapeutic development. Aim. This study aimed to assess the in vivo anti-leishmanial effect of the Gossypium hirsutum extract, and its fractions compared to the standard drug (Glucantime, MA) in a murine model and explore the mechanism of action. Methodology. Footpads of BALB/c mice were infected with stationary phase promastigotes and treated topically and intraperitoneally with G. hirsutum extract, its fractions, or Glucantime, 4 weeks post-infection. The extract and fractions were prepared using the Soxhlet apparatus with chloroform followed by the column procedure. Results. The crude extract significantly decreased the footpad parasite load and lesion size compared to the untreated control group (P<0.05), as revealed by dilution assay, quantitative real-time PCR, and histopathological analyses. The primary mode of action involved an immunomodulatory role towards the Th1 response in the up-regulation of IFN-γ and IL-12 and the suppression of IL-10 gene expression profiling against cutaneous leishmaniasis caused by Leishmania major. Conclusion. This finding suggests that the extract possesses multiple combinatory effects of diverse bioactive phytochemical compositions that exert its mechanisms of action through agonistic-synergistic interactions. The topical extract formulation could be a suitable and unique candidate for future investigation and pharmacological development. Further studies are crucial to evaluate the therapeutic potentials of the extract alone and in combination with conventional drugs using clinical settings.

scholarly journals Deletion of Interleukin-4 Receptor Alpha-Responsive Keratinocytes in BALB/c Mice Does Not Alter Susceptibility to Cutaneous Leishmaniasis

2018 ◽  
Vol 86 (12) ◽  
Author(s):  
Melissa Govender ◽  
Ramona Hurdayal ◽  
Berenice Martinez-Salazar ◽  
Kaya Gqada ◽  
Shandre Pillay ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Interleukin 4 ◽  
High Dose ◽  
Littermate Control ◽  
Content Type ◽  
Receptor Alpha ◽  
Th2 Immune Response

ABSTRACTThe skin microenvironment at the site of infection plays a role in the early events that determine protective T helper 1/type 1 immune responses during cutaneous leishmaniasis (CL) infection. During CL in nonhealing BALB/c mice, early interleukin-4 (IL-4) can instruct dendritic cells for protective Th1 immunity. Additionally, keratinocytes, which are the principal cell type in the skin epidermis, have been shown to secrete IL-4 early afterLeishmania majorinfection. Here, we investigated whether IL-4/IL-13 signaling via the common IL-4 receptor alpha chain (IL-4Rα) on keratinocytes contributes to susceptibility during experimental CL. To address this, keratinocyte-specific IL-4Rα-deficient (KRT14creIL-4Rα−/lox) mice on a BALB/c genetic background were generated by gene targeting and site-specific recombination (Cre/loxP) under the control of the keratinocyte-specifickrt14locus. Following high-dose infection withL. majorIL-81 and LV39 promastigotes subcutaneously in the footpad, footpad swelling, parasite burden, IFN-γ/IL-4/IL-13 cytokine production, and type 1 and type 2 antibody responses were similar between KRT14creIL-4Rα−/loxand littermate control IL-4Rα−/loxBALB/c mice. An intradermal infection with low-doseL. majorIL-81 and LV39 promastigotes in the ear showed results in infected KRT14creIL-4Rα−/loxBALB/c mice similar to those of littermate control IL-4Rα−/loxBALB/c mice, with the exception of a significant decrease observed in parasite burden only at the site of LV39 infection in the ear. Collectively, our results show that autocrine and paracrine signaling of IL-4/IL-13 through the IL-4Rα chain on keratinocytes does not influence the establishment of a nonhealing Th2 immune response in BALB/c mice duringL. majorinfection.

scholarly journals Impact of Interleukin-27p28 on T and B Cell Responses during Toxoplasmosis

2019 ◽  
Vol 87 (12) ◽  
Author(s):  
Jeongho Park ◽  
Jonathan H. DeLong ◽  
James J. Knox ◽  
Christoph Konradt ◽  
Elia D. Tait Wojno ◽  
...  
Keyword(s):  
T Cell ◽  
Ectopic Expression ◽  
Parasite Burden ◽  
Inhibitory Effect ◽  
Immune Serum ◽  
Negative Regulator ◽  
Content Type ◽  
Antibody Titers ◽  
The Central Nervous System ◽  
Parasite Replication

ABSTRACT Interleukin-27 (IL-27) is a heterodimeric cytokine composed of the subunits IL-27p28 and EBi3, and while the IL-27 heterodimer influences T cell activities, there is evidence that IL-27p28 can have EBi3-independent activities; however, their relevance to infection is unclear. Therefore, the studies presented here compared how IL-27p28 transgenics and IL-27p28−/− mice responded to the intracellular parasite Toxoplasma gondii. While the loss of IL-27p28 and its overexpression both result in increased susceptibility to T. gondii, the basis for this phenotype reveals distinct roles for IL-27p28. As a component of IL-27, IL-27p28 is critical to limit infection-induced T cell-mediated pathology, whereas the ectopic expression of IL-27p28 reduced the effector T cell population and had a major inhibitory effect on parasite-specific antibody titers and a failure to control parasite replication in the central nervous system. Indeed, transfer of immune serum to infected IL-27p28 transgenics resulted in reduced parasite burden and pathology. Thus, IL-27p28, independent of its role as a component of IL-27, can act as a negative regulator of humoral and cellular responses during toxoplasmosis.

scholarly journals Development of anEx VivoLymph Node Explant Model for Identification of Novel Molecules Active against Leishmania major

2013 ◽  
Vol 58 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Alex G. Peniche ◽  
Yaneth Osorio ◽  
Adam R. Renslo ◽  
Doug E. Frantz ◽  
Peter C. Melby ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Drug Efficacy ◽  
Peritoneal Macrophages ◽  
Effective Concentration ◽  
Content Type ◽  
Drug Candidates ◽  
New Drug ◽  
Vector Borne

ABSTRACTLeishmaniasis is a vector-borne zoonotic infection affecting people in tropical and subtropical regions of the world. Current treatments for cutaneous leishmaniasis are difficult to administer, toxic, expensive, and limited in effectiveness and availability. Here we describe the development and application of a medium-throughput screening approach to identify new drug candidates for cutaneous leishmaniasis using anex vivolymph nodeexplantculture (ELEC) derived from the draining lymph nodes ofLeishmania major-infected mice. The ELEC supported intracellular amastigote proliferation and contained lymph node cell populations (and their secreted products) that enabled the testing of compounds within a system that mimicked the immunopathological environment of the infected host, which is known to profoundly influence parasite replication, killing, and drug efficacy. The activity of known antileishmanial drugs in the ELEC system was similar to the activity measured in peritoneal macrophages infectedin vitrowithL. major. Using the ELEC system, we screened a collection of 334 compounds, some of which we had demonstrated previously to be active againstL. donovani, and identified 119 hits, 85% of which were confirmed to be active by determination of the 50% effective concentration (EC50). We found 24 compounds (7%) that had aninvitrotherapeuticindex (IVTI; 50% cytotoxic/effective concentration [CC50]/EC50) > 100; 19 of the compounds had an EC50below 1 μM. According to PubChem searchs, 17 of those compounds had not previously been reported to be active againstLeishmania. We expect that this novel method will help to accelerate discovery of new drug candidates for treatment of cutaneous leishmaniasis.

scholarly journals Antileishmanial Effects of Synthetic EhPIb Analogs Derived from the Entamoeba histolytica Lipopeptidephosphoglycan

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
Helena Fehling ◽  
Siew Ling Choy ◽  
Frederic Ting ◽  
Dirk Landschulze ◽  
Hannah Bernin ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Entamoeba Histolytica ◽  
Murine Model ◽  
Leishmania Major ◽  
Interleukin 4 ◽  
Intestinal Protozoan ◽  
Cutaneous Lesions ◽  
Content Type ◽  
Arginase 1

ABSTRACT With an estimated number of new cases annually of approximately 1.4 million, leishmaniasis belongs to the most important parasitic diseases in the world. Nevertheless, existing drugs against leishmaniasis in general have several drawbacks that urgently necessitate new drug development. A glycolipid molecule of the intestinal protozoan parasite Entamoeba histolytica and its synthetic analogs previously showed considerable immunotherapeutic effects against Leishmania major infection. Here, we designed and synthesized a series of new immunostimulatory compounds derived from the phosphatidylinositol b anchor of Entamoeba histolytica (EhPIb) subunit of the native compound and investigated their antileishmanial activity in vitro and in vivo in a murine model of cutaneous leishmaniasis. The new synthetic EhPIb analogs showed almost no toxicity in vitro. Treatment with the analogs significantly decreased the parasite load in murine and human macrophages in vitro. In addition, topical application of the EhPIb analog Eh-1 significantly reduced cutaneous lesions in the murine model, correlating with an increase in the production of selected Th1 cytokines. In addition, we could show in in vitro experiments that treatment with Eh-1 led to a decrease in mRNA expression of arginase-1 (Arg1) and interleukin 4 (IL-4), which are required by the parasites to circumvent their elimination by the immune response. The use of the host-targeting synthetic EhPIb compounds, either alone or in combination therapy with antiparasitic drugs, shows promise for treating cutaneous leishmaniasis and therefore might improve the current unsatisfactory status of chemotherapy against this infectious disease.

scholarly journals Antimalarial Activity of Tulathromycin in a Murine Model of Malaria

2015 ◽  
Vol 59 (6) ◽  
pp. 3672-3674 ◽  
Author(s):  
Nicolas Villarino ◽  
Joshua E. Denny ◽  
Nathan W. Schmidt
Keyword(s):  
Murine Model ◽  
Antimalarial Activity ◽  
Parasite Burden ◽  
Plasmodium Yoelii ◽  
Content Type ◽  
Antimalarial Agents ◽  
Progression Of Disease ◽  
Time Of Infection ◽  
And Control

ABSTRACTThere is an urgent need for new antimalarial agents and strategies to treat and control malaria. This study shows an antiplasmodium effect of tulathromycin in mice infected withPlasmodium yoelii. The administration of tulathromycin around the time of infection prevented the progression of disease in 100% of the animals. In addition, highly parasitized mice treated with tulathromycin showed a decreased parasite burden and cleared the parasite faster than did untreated infected mice.

scholarly journals Evaluating Aziridinyl Nitrobenzamide Compounds as Leishmanicidal Prodrugs

2013 ◽  
Vol 58 (1) ◽  
pp. 370-377 ◽  
Author(s):  
Andrew A. Voak ◽  
Karin Seifert ◽  
Nuala A. Helsby ◽  
Shane R. Wilkinson
Keyword(s):  
Mammalian Cells ◽  
Leishmania Major ◽  
Inhibitory Effect ◽  
Luciferase Reporter ◽  
Flavin Mononucleotide ◽  
Infection Model ◽  
Type I ◽  
Luciferase Reporter Gene ◽  
Content Type ◽  
Growth Inhibitory

ABSTRACTMany of the nitroaromatic agents used in medicine function as prodrugs and must undergo activation before exerting their toxic effects. In most cases, this is catalyzed by flavin mononucleotide (FMN)-dependent type I nitroreductases (NTRs), a class of enzyme absent from higher eukaryotes but expressed by bacteria and several eukaryotic microbes, including trypanosomes andLeishmania. Here, we utilize this difference to evaluate whether members of a library of aziridinyl nitrobenzamides have activity againstLeishmania major. Biochemical screens using purifiedL. majorNTR (LmNTR) revealed that compounds containing an aziridinyl-2,4-dinitrobenzyl core were effective substrates for the enzyme and showed that the 4-nitro group was important for this activity. To facilitate drug screening against intracellular amastigote parasites, we generated leishmanial cells that expressed the luciferase reporter gene and optimized a mammalian infection model in a 96-well plate format. A subset of aziridinyl-2,4-dinitrobenzyl compounds possessing a 5-amide substituent displayed significant growth-inhibitory properties against the parasite, with the most potent agents generating 50% inhibitory concentrations of <100 nM for the intracellular form. This antimicrobial activity was shown to be LmNTR specific sinceL. major NTR+/−heterozygote parasites were slightly resistance to most aziridinyl dinitrobenzyl agents tested. When the most potent leishmanicidal agents were screened against the mammalian cells in which the amastigote parasites were propagated, no growth-inhibitory effect was observed at concentrations of up to 100 μM. We conclude that the aziridinyl nitrobenzamides represent a new lead structure that may have the potential to treat leishmanial infections.

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