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Nwonuma CO, Balogun EA, Gyebi GA. Evaluation of Antimalarial Activity of Ethanolic Extract of Annona muricata L.: An in vivo and an in silico Approach. J Evid Based Integr Med 2023; 28:2515690X231165104. [PMID: 37019435 PMCID: PMC10084581 DOI: 10.1177/2515690x231165104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
In Nigeria, Annona muricata L. has been used to treat a variety of ailments. The mechanism of the antimalarial activity of ethanolic leaf extract of Annona muricata (EEAML) was investigated using both an in vivo and an in silico approach. The experimental mice were divided into five groups: A-F. The mice in groups B-F were inoculated with Plasmodium berghei NK-65 and treated accordingly. Groups A and B are the negative and positive controls (infected and untreated), respectively. Group C received 10 mg/kg chloroquine (standard drug), whereas groups D-F received 100, 200, and 300 mg/kg body weight of the extract orally respectively. The mice were euthanized eight days after infection, and their liver and blood were collected and used in biochemical tests. Molecular docking was performed using the extract's HPLC compounds and Plasmodium falciparum proteins. In the suppressive, prophylactic, and curative tests, there was a significant decrease (p < 0.05) in parasitemia levels in groups treated with the extract compared to the positive control and standard drug. When compared to the positive control, there was a significant (p < 0.05) reduction in liver MDA, total cholesterol, and total triglyceride levels. The binding energies of luteolin and apigenin-pfprotein complexes were significantly (p < 0.05) higher compared to their respective references. The anti-plasmodial activity of the extract may result from its hypolipidemic effect, which deprives the parasite of essential lipid molecules needed for parasite growth, as well as from the inhibitory effects of apigenin and luteolin on specific proteins required for the Plasmodium metabolic pathway.
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Affiliation(s)
- Charles Obiora Nwonuma
- Department of Biochemistry, College of Pure and Applied Science, Landmark University, Omu-Aran, Kwara State, Nigeria
| | | | - Gideon Ampoma Gyebi
- Department of Biochemistry, Faculty of Science and Technology, Bingham University, Karu, Nigeria
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Adebayo J, Ceravolo I, Gyebi G, Olorundare E, Babatunde A, Penna-Coutinho J, Koketsu M, Krettli A. Iloneoside, an antimalarial pregnane glycoside isolated from Gongronema latifolium leaf, potentiates the activity of chloroquine against multidrug resistant Plasmodium falciparum. Mol Biochem Parasitol 2022; 249:111474. [DOI: 10.1016/j.molbiopara.2022.111474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2021] [Revised: 03/09/2022] [Accepted: 03/13/2022] [Indexed: 10/18/2022]
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Bueno JM, Calderon F, Chicharro J, De la Rosa JC, Díaz B, Fernández J, Fiandor JM, Fraile MT, García M, Herreros E, García-Pérez A, Lorenzo M, Mallo A, Puente M, Saadeddin A, Ferrer S, Angulo-Barturen I, Burrows JN, León ML. Synthesis and Structure-Activity Relationships of the Novel Antimalarials 5-Pyridinyl-4(1 H)-Pyridones. J Med Chem 2018; 61:3422-3435. [PMID: 29589932 DOI: 10.1021/acs.jmedchem.7b01256] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Malaria is still one of the most prevalent parasitic infections in the world, with half of the world's population at risk for malaria. The effectiveness of current antimalarial therapies, even that of the most recent class of antimalarial drugs (artemisinin-combination therapies, ACTs), is under continuous threat by the spread of resistant Plasmodium strains. As a consequence, there is still an urgent requirement for new antimalarial drugs. We previously reported the identification of 4(1 H)-pyridones as a novel series with potent antimalarial activities. The low solubility was identified as an issue to address. In this paper, we describe the synthesis and biological evaluation of 4(1 H)-pyridones with potent antimalarial activities in vitro and in vivo and improved pharmacokinetic profiles. Their main structural novelties are the presence of polar moieties, such as hydroxyl groups, and the replacement of the lipophilic phenyl rings with pyridines on their lipophilic side chains.
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Affiliation(s)
- José M Bueno
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Félix Calderon
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Jesús Chicharro
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Juan C De la Rosa
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Beatriz Díaz
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Jorge Fernández
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - José M Fiandor
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - María T Fraile
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Mercedes García
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Esperanza Herreros
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Adolfo García-Pérez
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Milagros Lorenzo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Araceli Mallo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Margarita Puente
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Anas Saadeddin
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Santiago Ferrer
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Iñigo Angulo-Barturen
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
| | - Jeremy N Burrows
- Medicines for Malaria Venture, ICC , Route de Pré-Bois 20 , PO Box 1826, 1215 Geneva , Switzerland
| | - María L León
- Tres Cantos Medicines Development Campus, Diseases of the Developing World , GlaxoSmithKline , Calle de Severo Ochoa, 2 , 28760 Tres Cantos , Madrid , Spain
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Chalcone scaffolds as anti-infective agents: structural and molecular target perspectives. Eur J Med Chem 2015; 101:496-524. [PMID: 26188621 DOI: 10.1016/j.ejmech.2015.06.052] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/27/2015] [Accepted: 06/28/2015] [Indexed: 12/11/2022]
Abstract
In recent years, widespread outbreak of numerous infectious diseases across the globe has created havoc among the population. Particularly, the inhabitants of tropical and sub-tropical regions are mainly affected by these pathogens. Several natural and (semi) synthetic chalcones deserve the credit of being potential anti-infective candidates that inhibit various parasitic, malarial, bacterial, viral, and fungal targets like cruzain-1/2, trypanopain-Tb, trans-sialidase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fumarate reductase, falcipain-1/2, β-hematin, topoisomerase-II, plasmepsin-II, lactate dehydrogenase, protein kinases (Pfmrk and PfPK5), and sorbitol-induced hemolysis, DEN-1 NS3, H1N1, HIV (Integrase/Protease), protein tyrosine phosphatase A/B (Ptp-A/B), FtsZ, FAS-II, lactate/isocitrate dehydrogenase, NorA efflux pump, DNA gyrase, fatty acid synthase, chitin synthase, and β-(1,3)-glucan synthase. In this review, a comprehensive study (from Jan. 1982 to May 2015) of the structural features of anti-infective chalcones, their mechanism of actions (MOAs) and structure activity relationships (SARs) have been highlighted. With the knowledge of molecular targets, structural insights and SARs, this review may be helpful for (medicinal) chemists to design more potent, safe, selective and cost effective anti-infective agents.
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Siregar JE, Kurisu G, Kobayashi T, Matsuzaki M, Sakamoto K, Mi-ichi F, Watanabe YI, Hirai M, Matsuoka H, Syafruddin D, Marzuki S, Kita K. Direct evidence for the atovaquone action on the Plasmodium cytochrome bc1 complex. Parasitol Int 2014; 64:295-300. [PMID: 25264100 DOI: 10.1016/j.parint.2014.09.011] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Revised: 09/09/2014] [Accepted: 09/15/2014] [Indexed: 11/16/2022]
Abstract
Atovaquone, a coenzyme Q analogue has been indicated to specifically target the cytochrome bc1 complex of the mitochondrial respiratory chain in the malarial parasite and other protozoan. Various mutations in the quinone binding site of the cytochrome b gene of Plasmodium spp. such as M133I, L144S, L271V, K272R, Y268C, Y268S, Y268N, and V284F are suggesting to associate with resistance to atovaquone. There is no direct evidence of relation between the mutations and resistance to atovaquone in Plasmodium parasite that has been available. Technical difficulties in isolating active assayable mitochondria in the malarial parasite hinder us to obtain direct biochemical evidence to support the relation between the mutations and drug resistance. The establishment of a mitochondrial isolation method for the malaria parasite has allowed us to test the degree of resistance of Plasmodium berghei isolates to atovaquone directly. We have tested the activity of dihydroorotate (DHO)-cytochrome c reductase in various P. berghei atovaquone resistant clones in the presence of a wide concentration range of atovaquone. Our results show the IC(50) of P. berghei atovaquone resistant clones is much higher (1.5 up to 40 nM) in comparison to the atovaquone sensitive clones (0.132-0.465 nM). The highest IC(50) was revealed in clones carrying Y268C and Y268N mutations (which play an important role in atovaquone resistance in Plasmodium falciparum), with an approximately 100-fold increase. The findings indicate the importance of the mutation in the quinone binding site of the cytochrome b gene and that provide a direct evidence for the atovaquone inhibitory mechanism in the cytochrome bc1 complex of the parasite.
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Affiliation(s)
- Josephine E Siregar
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan
| | - Tamaki Kobayashi
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Motomichi Matsuzaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Kimitoshi Sakamoto
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Fumika Mi-ichi
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Yoh-ichi Watanabe
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Makoto Hirai
- Department of Medical Zoology, Jichi Medical School, Minami-kawachi, Tochigi 329-0498, Japan
| | - Hiroyuki Matsuoka
- Department of Medical Zoology, Jichi Medical School, Minami-kawachi, Tochigi 329-0498, Japan
| | - Din Syafruddin
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Sangkot Marzuki
- Eijkman Institute for Molecular Biology, Jl. Diponegoro 69, Jakarta 10430, Indonesia
| | - Kiyoshi Kita
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
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An FtsH protease is recruited to the mitochondrion of Plasmodium falciparum. PLoS One 2013; 8:e74408. [PMID: 24058559 PMCID: PMC3772908 DOI: 10.1371/journal.pone.0074408] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
The two organelles, apicoplast and mitochondrion, of the malaria parasite Plasmodium falciparum have unique morphology in liver and blood stages; they undergo complex branching and looping prior to division and segregation into daughter merozoites. Little is known about the molecular processes and proteins involved in organelle biogenesis in the parasite. We report the identification of an AAA+/FtsH protease homolog (PfFtsH1) that exhibits ATP- and Zn(2+)-dependent protease activity. PfFtsH1 undergoes processing, forms oligomeric assemblies, and is associated with the membrane fraction of the parasite cell. Generation of a transfectant parasite line with hemagglutinin-tagged PfFtsH1, and immunofluorescence assay with anti-PfFtsH1 Ab demonstrated that the protein localises to P. falciparum mitochondria. Phylogenetic analysis and the single transmembrane region identifiable in PfFtsH1 suggest that it is an i-AAA like inner mitochondrial membrane protein. Expression of PfFtsH1 in Escherichia coli converted a fraction of bacterial cells into division-defective filamentous forms implying a sequestering effect of the Plasmodium factor on the bacterial homolog, indicative of functional conservation with EcFtsH. These results identify a membrane-associated mitochondrial AAA+/FtsH protease as a candidate regulatory protein for organelle biogenesis in P. falciparum.
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Exploration of 4(1H)-pyridones as a novel family of potent antimalarial inhibitors of the plasmodial cytochrome bc1. Future Med Chem 2013; 4:2311-23. [PMID: 23234553 DOI: 10.4155/fmc.12.177] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A novel family of antimalarials based on the 4(1H)-pyridone scaffold is described. The compounds display potent antimalarial activity against Plasmodium falciparum in vitro and in vivo. Like atovaquone, 4(1H)-pyridones exert their antimalarial action by inhibiting selectively the electron-transport chain in P. falciparum at the cytochrome bc1 level (complex III). However, despite the similar mechanism of action, no cross-resistance with atovaquone has been found, suggesting that the binding mode of 4(1H)-pyridones might be different from that of atovaquone. The medicinal chemistry program, focused on improving potency and physicochemical properties, ultimately led to the discovery of GSK932121, which was progressed efficiently into first time in human studies. However, progression of GSK932121 was terminated when new toxicology results were obtained in the rat with a soluble phosphate prodrug of the candidate, indicating a potentially narrow therapeutic index.
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Torrentino-Madamet M, Almeras L, Travaillé C, Sinou V, Pophillat M, Belghazi M, Fourquet P, Jammes Y, Parzy D. Proteomic analysis revealed alterations of the Plasmodium falciparum metabolism following salicylhydroxamic acid exposure. Res Rep Trop Med 2011; 2:109-119. [PMID: 30881184 DOI: 10.2147/rrtm.s23127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES Although human respiratory metabolism is characterized by the mitochondrial electron transport chain, some organisms present a "branched respiratory chain." This branched pathway includes both a classical and an alternative respiratory chain. The latter involves an alternative oxidase. Though the Plasmodium falciparum alternative oxidase is not yet identified, a specific inhibitor of this enzyme, salicylhydroxamic acid (SHAM), showed a drug effect on P. falciparum respiratory function using oxygen consumption measurements. The present study aimed to highlight the metabolic pathways that are affected in P. falciparum following SHAM exposure. DESIGN A proteomic approach was used to analyze the P. falciparum proteome and determine the metabolic pathways altered following SHAM treatment. To evaluate the SHAM effect on parasite growth, the phenotypic alterations of P. falciparum after SHAM or/and hyperoxia exposure were observed. RESULTS After SHAM exposure, 26 proteins were significantly deregulated using a fluorescent two dimensional-differential gel electrophoresis. Among these deregulated proteins, some were particularly involved in energetic metabolism. And the combinatory effect of SHAM/hyperoxia seems deleterious for the growth of P. falciparum. CONCLUSION Our results indicated that SHAM appears to activate glycolysis and decrease stress defense systems. These data provide a better understanding of parasite biology.
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Affiliation(s)
| | - Lionel Almeras
- Unité de Recherche en Biologie et Epidémiologie Parasitaires, Antenne IRBA de Marseille (IMTSSA, Le Pharo)
| | - Christelle Travaillé
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
| | - Véronique Sinou
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
| | - Matthieu Pophillat
- Centre d'Immunologie de Marseille Luminy, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de la Méditerranée
| | - Maya Belghazi
- Centre d'Analyse Protéomique de Marseille, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord
| | - Patrick Fourquet
- Centre d'Immunologie de Marseille Luminy, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Université de la Méditerranée
| | - Yves Jammes
- UMR-MD2, Physiologie et Physiopathologie en Conditions d'Oxygénations Extrêmes, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord, Marseille, France
| | - Daniel Parzy
- UMR-MD3, Université de la Méditerranée, Antenne IRBA de Marseille (IMTSSA, Le Pharo),
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Vernon C, Letourneau JL. Lactic acidosis: recognition, kinetics, and associated prognosis. Crit Care Clin 2010; 26:255-83, table of contents. [PMID: 20381719 DOI: 10.1016/j.ccc.2009.12.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Lactic acidosis is a common condition encountered by critical care providers. Elevated lactate and decreased lactate clearance are important for prognostication. Not all lactate in the intensive care unit is due to tissue hypoxia or ischemia and other sources should be evaluated. Lactate, in and of itself, is unlikely to be harmful and is a preferred fuel for many cells. Treatment of lactic acidosis continues to be aimed the underlying source.
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Affiliation(s)
- Christopher Vernon
- Division of Pulmonary and Critical Care Medicine, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, UHN 67, Portland, OR 97239, USA
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Takashima E, Konishi K. Characterization of a quinol peroxidase mutant in Aggregatibacter actinomycetemcomitans. FEMS Microbiol Lett 2008; 286:66-70. [PMID: 18616592 DOI: 10.1111/j.1574-6968.2008.01253.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Aggregatibacter actinomycetemcomitans is an oral pathogen causing localized aggressive periodontitis (LAP). Recently, we characterized for the first time a quinol peroxidase (QPO) that catalyzes peroxidase activity using quinol in the respiratory chain of A. actinomycetemcomitans for the reduction of hydrogen peroxide. In the present study, we characterized the phenotype of a QPO null mutant. The QPO null mutant shows an oxidative stress phenotype, suggesting that QPO plays a certain role in scavenging endogenously generated reactive oxygen species. Notably, we discovered that the QPO null mutant exhibits a production defect of leukotoxin (LtxA), which is a secreted bacterial toxin and is known to target human leukocytes and erythrocytes. This result suggests that QPO would be considered as a potential drug target to inhibit the expression of LtxA from A. actinomycetemcomitans for the treatment and prevention of LAP.
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Affiliation(s)
- Eizo Takashima
- Department of Microbiology, School of Life Dentistry at Tokyo, Nippon Dental University, Tokyo, Japan.
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11
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Yeates CL, Batchelor JF, Capon EC, Cheesman NJ, Fry M, Hudson AT, Pudney M, Trimming H, Woolven J, Bueno JM, Chicharro J, Fernández E, Fiandor JM, Gargallo-Viola D, Gómez de las Heras F, Herreros E, León ML. Synthesis and structure-activity relationships of 4-pyridones as potential antimalarials. J Med Chem 2008; 51:2845-52. [PMID: 18396855 DOI: 10.1021/jm0705760] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A series of diaryl ether substituted 4-pyridones have been identified as having potent antimalarial activity superior to that of chloroquine against Plasmodium falciparum in vitro and murine Plasmodium yoelii in vivo. These were derived from the anticoccidial drug clopidol through a systematic study of the effects of varying the side chain on activity. Relative to clopidol the most active compounds show >500-fold improvement in IC50 for inhibition of P. falciparum in vitro and about 100-fold improvement with respect to ED50 against P. yoelii in mice. These compounds have been shown elsewhere to act selectively by inhibition of mitochondrial electron transport at the cytochrome bc1 complex.
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Affiliation(s)
- Clive L Yeates
- Wellcome Research Laboratories, Langley Court, Beckenham, Kent, U.K
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van Dooren GG, Stimmler LM, McFadden GI. Metabolic maps and functions of the Plasmodium mitochondrion. FEMS Microbiol Rev 2006; 30:596-630. [PMID: 16774588 DOI: 10.1111/j.1574-6976.2006.00027.x] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The mitochondrion of Plasmodium species is a validated drug target. However, very little is known about the functions of this organelle. In this review, we utilize data available from the Plasmodium falciparum genome sequencing project to piece together putative metabolic pathways that occur in the parasite, comparing this with the existing biochemical and cell biological knowledge. The Plasmodium mitochondrion contains both conserved and unusual features, including an active electron transport chain and many of the necessary enzymes for coenzyme Q and iron-sulphur cluster biosynthesis. It also plays an important role in pyrimidine metabolism. The mitochondrion participates in an unusual hybrid haem biosynthesis pathway, with enzymes localizing in both the mitochondrion and plastid organelles. The function of the tricarboxylic acid cycle in the mitochondrion is unclear. We discuss directions for future research into this fascinating, yet enigmatic, organelle.
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Affiliation(s)
- Giel G van Dooren
- Plant Cell Biology Research Centre, School of Botany, University of Melbourne, Parkville, Victoria, Australia
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Hodges M, Yikilmaz E, Patterson G, Kasvosve I, Rouault TA, Gordeuk VR, Loyevsky M. An iron regulatory-like protein expressed in Plasmodium falciparum displays aconitase activity. Mol Biochem Parasitol 2005; 143:29-38. [PMID: 15963579 DOI: 10.1016/j.molbiopara.2005.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2005] [Accepted: 05/05/2005] [Indexed: 11/28/2022]
Abstract
Plasmodium falciparum iron regulatory-like protein (PfIRPa) has homology to both mammalian iron regulatory proteins and aconitases and is capable of binding RNA iron response elements. We examined the subcellular localization of PfIRPa and its enzymatic properties at low oxygen tension. Differential digitonin permeabilization of isolated trophozoites with subsequent Western blot analysis suggests that the localization of PfIRPa is predominantly in the membranous compartments of the parasite, such as the mitochondrion. Immunofluorescence analysis showed that PfIRPa colocalizes with heat shock protein 60 (Hsp60), a mitochondrial marker, and is also present in the parasitic cytosol/food vacuole. Under conditions favoring the formation of an iron-sulfur cluster, recombinant PfIRPa (rPfIRPa) had aconitase activity as detected by a colorimetric NADPH-MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. As assessed by the hydration of cis-aconitate spectrophotometrically at 240 nm, rPfIRPa had high affinity for cis-aconitate (Km=3.5 microM) but a low turnover number (Kcat= 3.3 s(-1)). The overall catalytic efficiency (Kcat/Km) of rPfIRPa was similar in magnitude to human cytosolic IRP1/aconitase and human mitochondrial aconitase. PfIRPa immunoprecipitated from parasite lysates also had aconitase activity, as assessed by an MTT-based assay. Our results provide evidence that PfIRPa localizes in the mitochondrion and in the cytosol/food vacuole and is able to demonstrate aconitase activity. Further understanding of the role of PfIRPa/aconitase in the regulation of P. falciparum homeostasis may contribute towards the development of novel antimalarial strategies against plasmodial species.
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Affiliation(s)
- Marcus Hodges
- The Center for Sickle Cell Disease, Howard University, Washington, DC 20059, USA
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Keithly JS, Langreth SG, Buttle KF, Mannella CA. Electron tomographic and ultrastructural analysis of the Cryptosporidium parvum relict mitochondrion, its associated membranes, and organelles. J Eukaryot Microbiol 2005; 52:132-40. [PMID: 15817118 DOI: 10.1111/j.1550-7408.2005.04-3317.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sporozoites of the apicomplexan Cryptosporidium parvum possess a small, membranous organelle sandwiched between the nucleus and crystalloid body. Based upon immunolabelling data, this organelle was identified as a relict mitochondrion. Transmission electron microscopy and tomographic reconstruction reveal the complex arrangement of membranes in the vicinity of this organelle, as well as its internal organization. The mitochondrion is enveloped by multiple segments of rough endoplasmic reticulum that extend from the outer nuclear envelope. In tomographic reconstructions of the mitochondrion, there is either a single, highly-folded inner membrane or multiple internal subcompartments (which might merge outside the reconstructed volume). The infoldings of the inner membrane lack the tubular "crista junctions" found in typical metazoan, fungal, and protist mitochondria. The absence of this highly conserved structural feature is congruent with the loss, through reductive evolution, of the normal oxidative phosphorylation machinery in C. parvum. It is proposed that the retention of a relict mitochondrion in C. parvum is a strategy for compartmentalizing away from the cytosol toxic ferrous iron and sulfide, which are needed for iron sulfur cluster biosynthesis, an essential function of mitochondria in all eukaryotes.
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Affiliation(s)
- Janet S Keithly
- Division of Infectious Diseases, Wadsworth Center, New York State Department of Health, Albany, New York 12201, USA.
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Yano K, Komaki-Yasuda K, Kobayashi T, Takemae H, Kita K, Kano S, Kawazu SI. Expression of mRNAs and proteins for peroxiredoxins in Plasmodium falciparum erythrocytic stage. Parasitol Int 2005; 54:35-41. [PMID: 15710548 DOI: 10.1016/j.parint.2004.08.005] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2004] [Accepted: 08/31/2004] [Indexed: 11/22/2022]
Abstract
mRNA and protein expression profiles for three peroxiredoxins (PfTPx-1, PfTPx-2 and Pf1-Cys-Prx) and a thioredoxin (PfTrx-1) of Plasmodium falciparum during the erythrocytic stage were examined by real-time quantitative reverse transcription-PCR (RT-PCR), Western blotting and confocal laser scanning microscopy. PfTPx-1 was expressed constitutively in the parasite cytoplasm throughout the erythrocytic stage, suggesting a housekeeping role of this enzyme for control of intercellular reactive oxygen species (ROS) in the parasite. Pf1-Cys-Prx showed elevated expression during the trophozoite and early schizont stages in the parasite cytoplasm, and this profile suggested that this peroxiredoxin (Prx) detoxifies metabolism-derived ROS such as those released from heme iron. The other 2-Cys Prx, PfTPx-2, was detected in mitochondria and was expressed in both the trophozoite and schizont stages. Detection of the Prx in mitochondria is consistent with recent reports of the existence of a respiratory chain, which produces ROS, in the mitochondria of P. falciparum. PfTrx-1 showed elevated expression during the trophozoite and schizont stages in the parasite cytoplasm. Finally, expression of these antioxidant protein genes is most likely regulated at the transcriptional level because their mRNA and protein expression profiles overlapped.
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Affiliation(s)
- Kazuhiko Yano
- Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
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Abstract
With the sequencing of the Plasmodium falciparum genome now complete, increasing attention is turning to the function of gene products and to cell-regulatory processes. The combination of in silico analyses with modern molecular and biophysical methods is leading to rapid advances in our understanding of the mechanisms underlying the biochemistry and physiology of the parasite and its host cell. In this brief review, we present a "snap shot" of recent work in this area, with particular emphasis on aspects relevant to the development of new antimalarial drugs.
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Affiliation(s)
- Katja Becker
- Department of Biochemistry, Interdisciplinary Research Center, Justus-Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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