Characterization of the respiratory chain of Leishmania donovani promastigotes

Santhamma, Kizhakkekara R.; Bhaduri, Amar

doi:10.1016/0166-6851(95)02510-3

Cited by 51 publications

(33 citation statements)

References 25 publications

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“…FRD catalyzes the reduction of fumarate to succinate, which is a key enzyme in anaerobic energy metabolism for many organisms respiring with fumarate as a terminal electron acceptor. This enzyme has been found among some bacteria such as Helicobacter pylori and Escherichia coli (16,18), among and protozoal parasites of the genera Trypanosoma (5,11,31,34), Plasmodium (14), and Leishmania (31), and in helminths (17,29). In mammalian cells, succinate is converted to fumarate by the action of SDH and then converted to malate via fumarase.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Fumarate Reductase in Leishmania major and L. donovani by Chalcones

Chen

Zhai

Christensen

et al. 2001

Antimicrob Agents Chemother

200

130

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Our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. Preliminary studies showed that these compounds destroyed the ultrastructure of Leishmania parasite mitochondria and inhibited the respiration and the activity of mitochondrial dehydrogenases of Leishmania parasites. The present study was designed to further investigate the mechanism of action of chalcones, focusing on the parasite respiratory chain. The data show that licochalcone A inhibited the activity of fumarate reductase (FRD) in the permeabilized Leishmania major promastigote and in the parasite mitochondria, and it also inhibited solubilized FRD and a purified FRD from L. donovani. Two other chalcones, 2,4-dimethoxy-4-allyloxychalcone (24m4ac) and 2,4-dimethoxy-4-butoxychalcone (24mbc), also exhibited inhibitory effects on the activity of solubilized FRD in L. major promastigotes. Although licochalcone A inhibited the activities of succinate dehydrogenase (SDH), NADH dehydrogenase (NDH), and succinate-and NADHcytochrome c reductases in the parasite mitochondria, the 50% inhibitory concentrations (IC 50 ) of licochalcone A for these enzymes were at least 20 times higher than that for FRD. The IC 50 of licochalcone A for SDH and NDH in human peripheral blood mononuclear cells were at least 70 times higher than that for FRD. These findings indicate that FRD, one of the enzymes of the parasite respiratory chain, might be the specific target for the chalcones tested. Since FRD exists in the Leishmania parasite and does not exist in mammalian cells, it could be an excellent target for antiprotozoal drugs.Leishmaniasis is a major and increasing public health problem, particularly in Africa, Asia, and Latin America (23, 37). Some 350 million people are at risk of infection with Leishmania spp., and more than 12 million people are infected with different species of the parasite. Each year, there are 1.5 million new cases, and 500,000 of these are visceral leishmaniasis, which is nearly always fatal if left untreated (23). Treatment of leishmaniasis is unsatisfactory in that the existing drugs require repeated parenteral administration, and none of them are effective in all cases or are totally free of side effects (1, 26, 37). Furthermore, large-scale clinical resistance to antimonials, the first-line antileishmanial drugs, has been reported recently. This resistance occurred in 5 to 70% of patients in some areas of endemicity (28, 36). There is, therefore, a great and urgent need for the development of new, effective, and safe drugs for the treatment of leishmaniasis.A number of investigations to explore potential antileishmanial drugs have been carried out during the last 2 decades (2,6,15,21,22,25,30,33,38). We have previously reported that chalcones have potent antileishmanial and antimalarial activities and might be developed into a new class of antileishmanial drugs (7-10, 39). Attempting to elucidate the antileishmanial mechanism of action of the chalcones, we have previously fou...

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Section: Discussionmentioning

confidence: 99%

Inhibition of Fumarate Reductase in Leishmania major and L. donovani by Chalcones

Chen

Zhai

Christensen

et al. 2001

Antimicrob Agents Chemother

200

130

View full text Add to dashboard Cite

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“…Cells were harvested and washed with respiration buffer (50 mM sucrose, 145 mM KCl, 5 mM NaCl, 1 mM EDTA, 1 mM MgCl 2 and 10 mM sodium-phosphate buffer, pH 7.4) and finally suspended in the same buffer. Oxygen uptake was determined with a Clarke type oxi-electrode 54 having a cell capacity of 2 ml. The oxygen electrode was calibrated with air-saturated water containing sodium metabisulphite.…”

Section: Study Of Parasite Ultrastructure By Temmentioning

confidence: 99%

Camptothecin induced mitochondrial dysfunction leading to programmed cell death in unicellular hemoflagellate Leishmania donovani

et al. 2004

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The parasites of the order kinetoplastidae including Leishmania spp. emerge from most ancient phylogenic branches of unicellular eukaryotic lineages. In their life cycle, topoisomerase I plays a significant role in carrying out vital cellular processes. Camptothecin (CPT), an inhibitor of DNA topoisomerase I, induces programmed cell death (PCD) both in the amastigotes and promastigotes form of L. donovani parasites. CPT-induced cellular dysfunction in L. donovani promastigotes is characterized by several cytoplasmic and nuclear features of apoptosis. CPT inhibits cellular respiration that results in mitochondrial hyperpolarization taking place by oligomycin-sensitive F0-F1 ATPase-like protein in leishmanial cells. During the early phase of activation, there is an increase in reactive oxygen species (ROS) inside cells, which causes subsequent elevation in the level of lipid peroxidation and decrease in reducing equivalents like GSH. Endogenous ROS formation and lipid peroxidation cause eventual loss of mitochondrial membrane potential. Furthermore, cytochrome c is released into the cytosol in a manner independent of involvement of CED3/CPP32 group of proteases and unlike mammalian cells it is insensitive to cyclosporin A. These events are followed by activation of both CED3/CPP32 and ICE group of proteases in PCD of Leishmania. Taken together, our study indicates that different biochemical events leading to apoptosis in leishmanial cells provide information that could be exploited to develop newer potential therapeutic targets.

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“…P/O Ratio Assays-P/O ratio (the relationship between ATP synthesis and oxygen consumption) in digitonin-permeabilized cells were carried out by measuring the oxygen consumption during the rapid burst of state 3 respiration after adding 0.1 mM ADP (45). The measurements were made on 1.0 ϫ 10 8 cells permeabilized with 30 g of digitonin/mg of protein for 5 min at 28°C in an assay buffer consisting of 200 mM sucrose, 10 mM phosphate buffer, pH 7.4, 1.0 mM EDTA, 2 mM MgCl 2 , and succinate (2.5 mM) as respiratory substrate.…”

Section: Generation Of Knock-out Strain For Lmncb5ormentioning

confidence: 99%

NAD(P)H Cytochrome b5 Oxidoreductase Deficiency in Leishmania major Results in Impaired Linoleate Synthesis Followed by Increased Oxidative Stress and Cell Death

Mukherjee

Santara

Das

et al. 2012

Journal of Biological Chemistry

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Background: NAD(P)H cytochrome b 5 oxidoreductase (Ncb5or) participates in a variety of metabolic conversions. Results: A new Ncb5or acts as a redox partner of ⌬12 fatty acid desaturase. Conclusion: Ncb5or null mutant suffers from impaired linoleate synthesis leading to oxidative stress and cell death. Significance: Our results have exposed a novel fatty acid synthesis pathway in L. major that differs from the mammalian system.

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Characterization of the respiratory chain of Leishmania donovani promastigotes

Cited by 51 publications

References 25 publications

Inhibition of Fumarate Reductase in Leishmania major and L. donovani by Chalcones

Inhibition of Fumarate Reductase in Leishmania major and L. donovani by Chalcones

Camptothecin induced mitochondrial dysfunction leading to programmed cell death in unicellular hemoflagellate Leishmania donovani

NAD(P)H Cytochrome b5 Oxidoreductase Deficiency in Leishmania major Results in Impaired Linoleate Synthesis Followed by Increased Oxidative Stress and Cell Death

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