Molecular mechanism underlying antileishmanial effect of oxabicyclo[3.3.1]nonanones: Inhibition of key redox enzymes of the pathogen

Saudagar, Prakash; Saha, Pipas; Saikia, Anil K.; Dubey, Vikash Kumar

doi:10.1016/j.ejpb.2013.08.014

Cited by 51 publications

(47 citation statements)

References 39 publications

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“…Untreated promastigotes of Leishmania donovani were used at a cell density of 2.5 ϫ 10 6 cells/ml, and staining with annexin V-FITC and propidium iodide (PI) was performed according to the instructions given by the manufacturer. The fluorescence of the stained promastigotes was detected with a BD FACSCalibur flow cytometer, and the results were analyzed using CellQuestPro software (14). Similarly, hypericin (18 M)-treated promastigotes, with or without trypanothione (0.5 M) or spermidine (100 M) supplementation, were analyzed for apoptosis/necrosis.…”

Section: Methodsmentioning

confidence: 99%

“…The effect of hypericin on the survival of Leishmania promastigotes was analyzed by using the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay (19), as reported in our earlier publications (14,15). In brief, 200 l of Leishmania promastigotes (2.5 ϫ 10 6 cells/ml) was treated with various doses (10 M, 20 M, 40 M, 80 M, and 100 M) of hypericin for 24 h at 25°C.…”

Section: Methodsmentioning

confidence: 99%

“…Analysis of apoptotic/necrotic features was performed as reported in our earlier publications, using an annexin V-fluorescein isothiocyanate (FITC) apoptosis kit from Life Technologies (14,15). Untreated promastigotes of Leishmania donovani were used at a cell density of 2.5 ϫ 10 6 cells/ml, and staining with annexin V-FITC and propidium iodide (PI) was performed according to the instructions given by the manufacturer.…”

Section: Methodsmentioning

confidence: 99%

“…The macrophage cell line (J774A.1) used in the study was obtained from the National Centre for Cell Science (NCCS) (Pune, India). The procedures for Leishmania donovani and macrophage cell line J774A.1 were optimized and reported in our previous publications (12)(13)(14)(15). Decarboxylated S-adenosylmethionine (dcSAM) was given by Keijiro Sameijima (Tokyo Metropolitan Kamagome Hospital, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…ROS production was also monitored in Leishmania promastigotes with trypanothione (0.5 M) or spermidine (100 M) supplementation followed by treatment with hypericin (18 M). The fluorescence of the probe, indicating ROS levels, was assessed and analyzed by using a BD FACSCalibur flow cytometer and CellQuestPro software (12)(13)(14)(15).…”

Section: Methodsmentioning

confidence: 99%

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Probing the Molecular Mechanism of Hypericin-Induced Parasite Death Provides Insight into the Role of Spermidine beyond Redox Metabolism in Leishmania donovani

Singh

Sarma

Katiyar

et al. 2015

Antimicrob Agents Chemother

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bHypericin, a natural compound from Hypericum perforatum (St. John's wort), has been identified as a specific inhibitor of Leishmania donovani spermidine synthase (LdSS) using integrated computational and biochemical approaches. Hypericin showed in vitro inhibition of recombinant LdSS enzyme activity. The in vivo estimation of spermidine levels in Leishmania promastigotes after hypericin treatment showed significant decreases in the spermidine pools of the parasites, indicating target specificity of the inhibitor molecule. The inhibitor, hypericin, showed significant antileishmanial activity, and the mode of death showed necrosis-like features. Further, decreased trypanothione levels and increased glutathione levels with elevated reactive oxygen species (ROS) levels were observed after hypericin treatment. Supplementation with trypanothione in the medium with hypericin treatment restored in vivo trypanothione levels and ROS levels but could not prevent necrosis-like death of the parasites. However, supplementation with spermidine in the medium with hypericin treatment restored in vivo spermidine levels and parasite death was prevented to a large extent. The data overall suggest that the parasite death due to spermidine starvation as a result of LdSS inhibition is not related to elevated levels of reactive oxygen species. This suggests the involvement of spermidine in processes other than redox metabolism in Leishmania parasites. Moreover, the work provides a novel scaffold, i.e., hypericin, as a potent antileishmanial molecule. Leishmaniasis is a widespread tropical disease caused by the protozoan parasite Leishmania, which belongs to the order Kinetoplastida and the family Trypanosomatidae. This parasite is transmitted by the vector sandfly, of the genera Phlebotomus and Lutzomyia. There are three forms of clinical manifestations of leishmaniasis, depending on the type of infecting species, namely, cutaneous, mucocutaneous, and visceral leishmaniasis (1). The most deadly form of the disease is visceral leishmaniasis, also known as kala-azar, which is caused mainly by Leishmania donovani in India. According to WHO statistics, 350 million people in 88 countries are at risk of developing the disease. Every year there are 2 million new cases of the disease, of which 0.5 million are cases of visceral leishmaniasis (2, 3). The treatment of leishmaniasis relies mainly on chemotherapy, as there are no vaccines available. Although many drugs are available on the market, they have several limitations (4, 5), indicating a need for novel drug candidates with specific drug targets.All aerobic organisms are exposed to oxidative stress and generate toxic reactive oxygen species (ROS) that can degrade DNA, modify proteins, and adversely affect survival of the organism. The amastigote form of the parasite resides and multiplies inside macrophages, which produce large amounts of hydrogen peroxide. Leishmania parasites are reported to be very sensitive to oxidative stress if the functions of trypanothione metabolism enzymes are d...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 3 more Smart Citations

Probing the Molecular Mechanism of Hypericin-Induced Parasite Death Provides Insight into the Role of Spermidine beyond Redox Metabolism in Leishmania donovani

Singh

Sarma

Katiyar

et al. 2015

Antimicrob Agents Chemother

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Identification of novel anti‐leishmanials targeting glutathione synthetase of the parasite: a drug repurposing approach

Sarma,

Bora,

Ranjan

et al. 2024

FEBS Letters

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Drug repurposing has emerged as an effective strategy against infectious diseases such as visceral leishmaniasis. Here, we evaluated four FDA‐approved drugs–valrubicin, ciclesonide, deflazacort, and telithromycin—for their anti‐leishmanial activity on Leishmania donovani parasites, especially their ability to target the enzyme glutathione synthetase (LdGS), which enables parasite survival under oxidative stress in host macrophages. Valrubicin and ciclesonide exhibited superior inhibitory effects compared to deflazacort and telithromycin, inhibiting the promastigotes at very low concentrations, with IC50 values of 1.09 ± 0.09 μm and 2.09 ± 0.09 μm, respectively. Subsequent testing on amastigotes revealed the IC50 values of 1.74 ± 0.05 μm and 3.32 ± 0.21 μm for valrubicin and ciclesonide, respectively. Molecular and cellular level analysis further elucidated the mechanisms underlying the anti‐leishmanial activity of valrubicin and ciclesonide.

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Recent Advancement in the Search of Innovative Antiprotozoal Agents Targeting Trypanothione Metabolism

2020

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Leishmania and Trypanosoma parasites are responsible for the challenging neglected tropical diseases leishmaniases, Chagas disease, and human African trypanosomiasis, which account for up to 40,000 deaths annually mainly in developing countries. Current chemotherapy relies on drugs with significant limitations in efficacy and safety, prompting the urgent need to explore innovative approaches to improve the drug discovery pipeline. The unique trypanothione‐based redox pathway, which is absent in human hosts, is vital for all trypanosomatids and offers valuable opportunities to guide the rational development of specific, broad‐spectrum and innovative anti‐trypanosomatid agents. Major efforts focused on the key metabolic enzymes trypanothione synthetase‐amidase and trypanothione reductase, whose inhibition should affect the entire pathway and, finally, parasite survival. Herein, we will report and comment on the most recent studies in the search for enzyme inhibitors, underlining the promising opportunities that have emerged so far to drive the exploration of future successful therapeutic approaches.

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Molecular mechanism underlying antileishmanial effect of oxabicyclo[3.3.1]nonanones: Inhibition of key redox enzymes of the pathogen

Cited by 51 publications

References 39 publications

Probing the Molecular Mechanism of Hypericin-Induced Parasite Death Provides Insight into the Role of Spermidine beyond Redox Metabolism in Leishmania donovani

Probing the Molecular Mechanism of Hypericin-Induced Parasite Death Provides Insight into the Role of Spermidine beyond Redox Metabolism in Leishmania donovani

Identification of novel anti‐leishmanials targeting glutathione synthetase of the parasite: a drug repurposing approach

Recent Advancement in the Search of Innovative Antiprotozoal Agents Targeting Trypanothione Metabolism

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