1
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Springer E, Heimsch KC, Rahlfs S, Becker K, Przyborski JM. Real-time measurements of ATP dynamics via ATeams in Plasmodium falciparum reveal drug-class-specific response patterns. Antimicrob Agents Chemother 2024; 68:e0169023. [PMID: 38501806 PMCID: PMC11064498 DOI: 10.1128/aac.01690-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/26/2024] [Indexed: 03/20/2024] Open
Abstract
Malaria tropica, caused by the parasite Plasmodium falciparum (P. falciparum), remains one of the greatest public health burdens for humankind. Due to its pivotal role in parasite survival, the energy metabolism of P. falciparum is an interesting target for drug design. To this end, analysis of the central metabolite adenosine triphosphate (ATP) is of great interest. So far, only cell-disruptive or intensiometric ATP assays have been available in this system, with various drawbacks for mechanistic interpretation and partly inconsistent results. To address this, we have established fluorescent probes, based on Förster resonance energy transfer (FRET) and known as ATeam, for use in blood-stage parasites. ATeams are capable of measuring MgATP2- levels in a ratiometric manner, thereby facilitating in cellulo measurements of ATP dynamics in real-time using fluorescence microscopy and plate reader detection and overcoming many of the obstacles of established ATP analysis methods. Additionally, we established a superfolder variant of the ratiometric pH sensor pHluorin (sfpHluorin) in P. falciparum to monitor pH homeostasis and control for pH fluctuations, which may affect ATeam measurements. We characterized recombinant ATeam and sfpHluorin protein in vitro and stably integrated the sensors into the genome of the P. falciparum NF54attB cell line. Using these new tools, we found distinct sensor response patterns caused by several different drug classes. Arylamino alcohols increased and redox cyclers decreased ATP; doxycycline caused first-cycle cytosol alkalization; and 4-aminoquinolines caused aberrant proteolysis. Our results open up a completely new perspective on drugs' mode of action, with possible implications for target identification and drug development.
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Affiliation(s)
- Eric Springer
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
| | - Kim C. Heimsch
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
| | - Stefan Rahlfs
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
| | - Jude M. Przyborski
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University, Giessen, Germany
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2
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Sam-Yellowe TY, Asraf MM, Peterson JW, Fujioka H. Fluorescent Nanoparticle Uptake by Myzocytosis and Endocytosis in Colpodella sp. ATCC 50594. Microorganisms 2023; 11:1945. [PMID: 37630505 PMCID: PMC10458597 DOI: 10.3390/microorganisms11081945] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 07/27/2023] [Accepted: 07/27/2023] [Indexed: 08/27/2023] Open
Abstract
Colpodella sp. (ATCC 50594) is a free-living biflagellate predator closely related to pathogenic Apicomplexa such as Plasmodium, Cryptosporidium and Toxoplasma gondii. Colpodella sp. (ATCC 50594) obtain nutrients by preying on Parabodo caudatus using myzocytosis. The organization of the myzocytic apparatus and the mechanism of nutrient uptake into the posterior food vacuole of Colpodella species is unknown. In this study, we investigated myzocytosis using light and transmission electron microscopy. We investigated the uptake of 40 nm and 100 nm fluorescent nanoparticles and E. coli BioParticles by Colpodella sp. (ATCC 50594) in a diprotist culture. Transmission electron microscopy was used to investigate the morphology of the tubular tether formed during myzocytosis. E. coli BioParticles were taken up by P. caudatus but not by Colpodella sp. (ATCC 50594). Both protists took up the 100 nm and 40 nm beads, which were observed distributed in the cytoplasm of free unattached Colpodella sp. (ATCC 50594) trophozoites, and also in feeding Colpodella sp. (ATCC 50594) trophozoites and in the pre-cysts. Fragments of the nucleus and kinetoplast of P. caudatus and the nanoparticles were identified in the tubular tether being aspirated into the posterior food vacuole of Colpodella sp. (ATCC 50594). Unattached Colpodella sp. (ATCC 50594) endocytose nutrients from the culture medium independently from myzocytosis. The mechanisms of myzocytosis and endocytosis among Colpodella species may provide important insights into nutrient uptake among the pathogenic apicomplexans.
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Affiliation(s)
- Tobili Y. Sam-Yellowe
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA;
| | - Mary M. Asraf
- Department of Biological, Geological and Environmental Sciences, Cleveland State University, Cleveland, OH 44115, USA;
| | - John W. Peterson
- Cleveland Clinic Lerner Research Institute, Cleveland, OH 44195, USA;
| | - Hisashi Fujioka
- Cryo-EM Core, Case Western Reserve University, Cleveland, OH 44106, USA;
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3
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Spirofused Tetrahydroisoquinoline-Oxindole Hybrids (Spiroquindolones) as Potential Multitarget Antimalarial Agents: Preliminary Hit Optimization and Efficacy Evaluation in Mice. Antimicrob Agents Chemother 2022; 66:e0060722. [PMID: 36409128 PMCID: PMC9765129 DOI: 10.1128/aac.00607-22] [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: 11/23/2022] Open
Abstract
Previous studies suggest that 3',5'-dihydro-2'H-spiro[indoline-3,1'-isoquinolin]-2-ones (DSIIQs [spiroquindolones]) are multitarget antiplasmodial agents that combine the actions of spiroindolone and naphthylisoquinoline antimalarial agents. In this study, 12 analogues of compound (±)-5 (moxiquindole), the prototypical spiroquindolone, were synthesized and tested for antiplasmodial activity. Compound (±)-11 (a mixture of compounds 11a and 11b), the most potent analogue, displayed low-nanomolar activity against P. falciparum chloroquine-sensitive 3D7 strain (50% inhibitory concentration [IC50] for 3D7 = 21 ± 02 nM) and was active against all major erythrocytic stages of the parasite life cycle (ring, trophozoite, and schizont); it also inhibited hemoglobin metabolism and caused extensive vacuolation in parasites. In drug-resistant parasites, compound (±)-11 exhibited potent activity (IC50 for Dd2 = 58.34 ± 2.04 nM) against the P. falciparum multidrug-resistant Dd2 strain, and both compounds (±)-5 and (±)-11 displayed significant cross-resistance against the P. falciparum ATP4 mutant parasite Dd2 SJ733 but not against the Dd2 KAE609 strain. In mice, both compounds (±)-5 and (±)-11 displayed dose-dependent reduction of parasitemia with suppressive 50% effective dose (ED50) values of 0.44 and 0.11 mg/kg of body weight, respectively. The compounds were also found to be curative in vivo and are thus worthy of further investigation.
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4
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Hidayati AR, Melinda, Ilmi H, Sakura T, Sakaguchi M, Ohmori J, Hartuti ED, Tumewu L, Inaoka DK, Tanjung M, Yoshida E, Tokumasu F, Kita K, Mori M, Dobashi K, Nozaki T, Syafruddin D, Hafid AF, Waluyo D, Widyawaruyanti A. Effect of geranylated dihydrochalcone from Artocarpus altilis leaves extract on Plasmodium falciparum ultrastructural changes and mitochondrial malate: Quinone oxidoreductase. Int J Parasitol Drugs Drug Resist 2022; 21:40-50. [PMID: 36565667 PMCID: PMC9798170 DOI: 10.1016/j.ijpddr.2022.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 12/05/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022]
Abstract
Nearly half of the world's population is at risk of being infected by Plasmodium falciparum, the pathogen of malaria. Increasing resistance to common antimalarial drugs has encouraged investigations to find compounds with different scaffolds. Extracts of Artocarpus altilis leaves have previously been reported to exhibit in vitro antimalarial activity against P. falciparum and in vivo activity against P. berghei. Despite these initial promising results, the active compound from A. altilis is yet to be identified. Here, we have identified 2-geranyl-2', 4', 3, 4-tetrahydroxy-dihydrochalcone (1) from A. altilis leaves as the active constituent of its antimalarial activity. Since natural chalcones have been reported to inhibit food vacuole and mitochondrial electron transport chain (ETC), the morphological changes in food vacuole and biochemical inhibition of ETC enzymes of (1) were investigated. In the presence of (1), intraerythrocytic asexual development was impaired, and according to the TEM analysis, this clearly affected the ultrastructure of food vacuoles. Amongst the ETC enzymes, (1) inhibited the mitochondrial malate: quinone oxidoreductase (PfMQO), and no inhibition could be observed on dihydroorotate dehydrogenase (DHODH) as well as bc1 complex activities. Our study suggests that (1) has a dual mechanism of action affecting the food vacuole and inhibition of PfMQO-related pathways in mitochondria.
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Affiliation(s)
- Agriana Rosmalina Hidayati
- Doctoral Program, Faculty of Pharmacy, Universitas Airlangga, Surabaya, Indonesia,Department of Pharmacy, Faculty of Medicine, Universitas Mataram, Mataram, Indonesia
| | - Melinda
- Research Center for Genetic Engineering, National Research and Innovation Agency (BRIN), Bogor, Indonesia
| | - Hilkatul Ilmi
- Center of Natural Product Medicine Research and Development, Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia
| | - Takaya Sakura
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Miako Sakaguchi
- Central Laboratory, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Junko Ohmori
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan
| | - Endah Dwi Hartuti
- Research Center for Genetic Engineering, National Research and Innovation Agency (BRIN), Bogor, Indonesia,Graduate School of Biomedical Science, Nagasaki University, Nagasaki, Japan
| | - Lidya Tumewu
- Center of Natural Product Medicine Research and Development, Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia
| | - Daniel Ken Inaoka
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan,School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan
| | - Mulyadi Tanjung
- Department of Chemistry, Faculty of Science and Technology, Universitas Airlangga, Surabaya, Indonesia
| | - Eri Yoshida
- Department of Molecular Infection Dynamics, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Fuyuki Tokumasu
- Department of Cellular Architecture Studies, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Kiyoshi Kita
- School of Tropical Medicine and Global Health, Nagasaki University, Nagasaki, Japan,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan,Department of Host-Defense Biochemistry, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Mihoko Mori
- Kitasato Institute for Life Science, Kitasato University, Tokyo, Japan
| | - Kazuyuki Dobashi
- Kitasato Institute for Life Science, Kitasato University, Tokyo, Japan
| | - Tomoyoshi Nozaki
- Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Japan
| | - Din Syafruddin
- Department of Parasitology, Faculty of Medicine, Hasanudin University, Makassar, Indonesia
| | - Achmad Fuad Hafid
- Center of Natural Product Medicine Research and Development, Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia,Department of Pharmaceutical Sciences, Faculty of Pharmacy, Universitas Airlangga, Surabaya, Indonesia
| | - Danang Waluyo
- Research Center for Genetic Engineering, National Research and Innovation Agency (BRIN), Bogor, Indonesia
| | - Aty Widyawaruyanti
- Center of Natural Product Medicine Research and Development, Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia,Department of Pharmaceutical Sciences, Faculty of Pharmacy, Universitas Airlangga, Surabaya, Indonesia,Corresponding author. Center of Natural Product Medicine Research and Development, Institute of Tropical Disease, Universitas Airlangga, Surabaya, Indonesia.
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5
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Chiang YH, Lin YC, Wang SY, Lee YP, Chen CF. Effects of Artemisia annua on experimentally induced leucocytozoonosis in chickens. Poult Sci 2021; 101:101690. [PMID: 35149282 PMCID: PMC8842078 DOI: 10.1016/j.psj.2021.101690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 11/29/2022] Open
Abstract
The biting midge Culicoides arakawae is the vector for the parasite Leucocytozoon caulleryi. Birds infected with L. caulleryi develop leucocytozoonosis. Given the food safety concern regarding drug residue in eggs, discovering a natural alternative to antibiotics is a worthy of exploration. Thus, we investigated the effects of the antimalarial herb Artemisia annua on experimentally induced leucocytozoonosis in chickens. We reared C. arakawae in the laboratory. Eggs were cultured, developing into larvae, pupae, and imagoes. Female midges sucked the blood of sick chickens and then were ground into a solution injected into healthy chickens. The control group was given empty capsules daily, whereas the 2 experimental groups were given 40 mg/kg sulfadimethoxine or 0.5 g of A. annua powder. Leucocytozoon gametocytes were detected in chicken blood through Giemsa staining. PCR detected the cytochrome b gene of L. caulleryi in the infected chickens. No significant among-group differences in body weight gain were observed before d 14 postinoculation (P > 0.05). Body weight gain in the control group was significantly lower from day 14 to 28 postinoculation (P < 0.05). After day 14, rectal temperature in the experimental groups decreased significantly compared with that in the control group. Lower rates of pale comb and green feces were observed in the animals receiving treatment from day 0. The experimental groups had a higher recovery rate and recovered earlier than did the control group. By day 31, all the animals had recovered. PCR detected L. caulleryi in the infected chickens with high sensitivity and accuracy. The animals receiving A. annua exhibited increased weight gain and reduced parasite concentrations in the blood. This in turn reduced mortality and the occurrence of pale comb and green feces. The findings are informative for research on leucocytozoonosis.
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Affiliation(s)
- Yu-Huan Chiang
- Department of Animal Science, National Chung Hsing University, Taichung 402, Taiwan
| | - Yen-Cheng Lin
- Department of Animal Science, National Chung Hsing University, Taichung 402, Taiwan
| | - Sheng-Yang Wang
- Department of Forestry, National Chung Hsing University, Taichung 402, Taiwan; Agricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan
| | - Yen-Pai Lee
- Department of Animal Science, National Chung Hsing University, Taichung 402, Taiwan
| | - Chih-Feng Chen
- Department of Animal Science, National Chung Hsing University, Taichung 402, Taiwan; The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan.
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6
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Bannerman BP, Júlvez J, Oarga A, Blundell TL, Moreno P, Floto RA. Integrated human/SARS-CoV-2 metabolic models present novel treatment strategies against COVID-19. Life Sci Alliance 2021; 4:e202000954. [PMID: 34353886 PMCID: PMC8343166 DOI: 10.26508/lsa.202000954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 07/26/2021] [Accepted: 07/27/2021] [Indexed: 01/20/2023] Open
Abstract
The coronavirus disease 2019 (COVID-19) pandemic caused by the new coronavirus (SARS-CoV-2) is currently responsible for more than 3 million deaths in 219 countries across the world and with more than 140 million cases. The absence of FDA-approved drugs against SARS-CoV-2 has highlighted an urgent need to design new drugs. We developed an integrated model of the human cell and SARS-CoV-2 to provide insight into the virus' pathogenic mechanism and support current therapeutic strategies. We show the biochemical reactions required for the growth and general maintenance of the human cell, first, in its healthy state. We then demonstrate how the entry of SARS-CoV-2 into the human cell causes biochemical and structural changes, leading to a change of cell functions or cell death. A new computational method that predicts 20 unique reactions as drug targets from our models and provides a platform for future studies on viral entry inhibition, immune regulation, and drug optimisation strategies. The model is available in BioModels (https://www.ebi.ac.uk/biomodels/MODEL2007210001) and the software tool, findCPcli, that implements the computational method is available at https://github.com/findCP/findCPcli.
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Affiliation(s)
- Bridget P Bannerman
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, Cambridge, UK
- The Center for Research and Interdisciplinarity, Paris, France
| | - Jorge Júlvez
- Department of Computer Science and Systems Engineering, University of Zaragoza, Zaragoza, Spain
| | - Alexandru Oarga
- Department of Computer Science and Systems Engineering, University of Zaragoza, Zaragoza, Spain
| | - Tom L Blundell
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Pablo Moreno
- EMBL-EBI, European Bioinformatics Institute, Hinxton, UK
| | - R Andres Floto
- Molecular Immunity Unit, Department of Medicine, University of Cambridge, Cambridge, UK
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7
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17-AAG-Induced Activation of the Autophagic Pathway in Leishmania Is Associated with Parasite Death. Microorganisms 2021; 9:microorganisms9051089. [PMID: 34069389 PMCID: PMC8158731 DOI: 10.3390/microorganisms9051089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/20/2021] [Accepted: 04/23/2021] [Indexed: 12/14/2022] Open
Abstract
The heat shock protein 90 (Hsp90) is thought to be an excellent drug target against parasitic diseases. The leishmanicidal effect of an Hsp90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin (17-AAG), was previously demonstrated in both in vitro and in vivo models of cutaneous leishmaniasis. Parasite death was shown to occur in association with severe ultrastructural alterations in Leishmania, suggestive of autophagic activation. We hypothesized that 17-AAG treatment results in the abnormal activation of the autophagic pathway, leading to parasite death. To elucidate this process, experiments were performed using transgenic parasites with GFP-ATG8-labelled autophagosomes. Mutant parasites treated with 17-AAG exhibited autophagosomes that did not entrap cargo, such as glycosomes, or fuse with lysosomes. ATG5-knockout (Δatg5) parasites, which are incapable of forming autophagosomes, demonstrated lower sensitivity to 17-AAG-induced cell death when compared to wild-type (WT) Leishmania, further supporting the role of autophagy in 17-AAG-induced cell death. In addition, Hsp90 inhibition resulted in greater accumulation of ubiquitylated proteins in both WT- and Δatg5-treated parasites compared to controls, in the absence of proteasome overload. In conjunction with previously described ultrastructural alterations, herein we present evidence that treatment with 17-AAG causes abnormal activation of the autophagic pathway, resulting in the formation of immature autophagosomes and, consequently, incidental parasite death.
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8
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Plasmodium falciparum Atg18 localizes to the food vacuole via interaction with the multi-drug resistance protein 1 and phosphatidylinositol 3-phosphate. Biochem J 2021; 478:1705-1732. [PMID: 33843972 DOI: 10.1042/bcj20210001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/10/2021] [Accepted: 04/12/2021] [Indexed: 12/27/2022]
Abstract
Autophagy, a lysosome-dependent degradative process, does not appear to be a major degradative process in malaria parasites and has a limited repertoire of genes. To better understand the autophagy process, we investigated Plasmodium falciparum Atg18 (PfAtg18), a PROPPIN family protein, whose members like S. cerevisiae Atg18 (ScAtg18) and human WIPI2 bind PI3P and play an essential role in autophagosome formation. Wild type and mutant PfAtg18 were expressed in P. falciparum and assessed for localization, the effect of various inhibitors and antimalarials on PfAtg18 localization, and identification of PfAtg18-interacting proteins. PfAtg18 is expressed in asexual erythrocytic stages and localized to the food vacuole, which was also observed with other Plasmodium Atg18 proteins, indicating that food vacuole localization is likely a shared feature. Interaction of PfAtg18 with the food vacuole-associated PI3P is essential for localization, as PfAtg18 mutants of PI3P-binding motifs neither bound PI3P nor localized to the food vacuole. Interestingly, wild type ScAtg18 interacted with PI3P, but its expression in P. falciparum showed complete cytoplasmic localization, indicating additional requirement for food vacuole localization. The food vacuole multi-drug resistance protein 1 (MDR1) was consistently identified in the immunoprecipitates of PfAtg18 and P. berghei Atg18, and also interacted with PfAtg18. In contrast with PfAtg18, ScAtg18 did not interact with MDR1, which, in addition to PI3P, could play a critical role in localization of PfAtg18. Chloroquine and amodiaquine caused cytoplasmic localization of PfAtg18, suggesting that these target PfAtg18 transport pathway. Thus, PI3P and MDR1 are critical mediators of PfAtg18 localization.
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9
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Efange NM, Lobe MMM, Keumoe R, Ayong L, Efange SMN. Spirofused tetrahydroisoquinoline-oxindole hybrids as a novel class of fast acting antimalarial agents with multiple modes of action. Sci Rep 2020; 10:17932. [PMID: 33087791 PMCID: PMC7578093 DOI: 10.1038/s41598-020-74824-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/07/2020] [Indexed: 11/15/2022] Open
Abstract
Molecular hybridization of privileged scaffolds may generate novel antiplasmodial chemotypes that display superior biological activity and delay drug resistance. In the present study, we describe the in vitro activities and mode of action of 3′,4′-dihydro-2′H-spiro[indoline-3,1′-isoquinolin]-2-ones, a novel class of spirofused tetrahydroisoquinoline–oxindole hybrids, as novel antimalarial agents. Whole cell phenotypic screening of these compounds identified (14b), subsequently named (±)-moxiquindole, as the most potent compound in the current series with equipotent antiplasmodial activity against both chloroquine sensitive and multidrug resistant parasite strains with good selectivity. The compound was active against all asexual stages of the parasite including inhibition of merozoite egress. Additionally, (±)-moxiquindole exhibited significant inhibitory effects on hemoglobin degradation, and disrupted vacuolar lipid dynamics. Taken together, our data confirm the antiplasmodial activity of (±)-moxiquindole, and identify 3′4′-dihydro-2′H-spiro[indoline-3,1′-isoquinolin]-2-ones as a novel class of antimalarial agents with multiple modes of action.
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Affiliation(s)
- Noella M Efange
- Department of Biochemistry and Molecular Biology, University of Buea, P.O. Box 63, Buea, Cameroon.,Centre Pasteur du Cameroon, Yaoundé, Cameroon
| | - Maloba M M Lobe
- Department of Chemistry, University of Buea, P.O. Box 63, Buea, Cameroon
| | | | | | - Simon M N Efange
- Department of Chemistry, University of Buea, P.O. Box 63, Buea, Cameroon.
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10
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Cytotoxic and Anti-Plasmodial Activities of Stephania dielsiana Y.C. Wu Extracts and the Isolated Compounds. Molecules 2020; 25:molecules25163755. [PMID: 32824689 PMCID: PMC7465040 DOI: 10.3390/molecules25163755] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/11/2020] [Accepted: 08/13/2020] [Indexed: 12/12/2022] Open
Abstract
Natural products remain a viable source of novel therapeutics, and as detection and extraction techniques improve, we can identify more molecules from a broader set of plant tissues. The aim of this study was an investigation of the cytotoxic and anti-plasmodial activities of the methanol extract from Stephania dielsiana Y.C. Wu leaves and its isolated compounds. Our study led to the isolation of seven alkaloids, among which oxostephanine (1) is the most active against several cancer cell lines including HeLa, MDA-MB231, MDA-MB-468, MCF-7, and non-cancer cell lines, such as 184B5 and MCF10A, with IC50 values ranging from 1.66 to 4.35 μM. Morever, oxostephanine (1) is on average two-fold more active against cancer cells than stephanine (3), having a similar chemical structure. Cells treated with oxostephanine (1) are arrested at G2/M cell cycle, followed by the formation of aneuploidy and apoptotic cell death. The G2/M arrest appears to be due, at least in part, to the inactivation of Aurora kinases, which is implicated in the onset and progression of many forms of human cancer. An in-silico molecular modeling study suggests that oxostephanine (1) binds to the ATP binding pocket of Aurora kinases to inactivate their activities. Unlike oxostephanine (1), thailandine (2) is highly effective against only the triple-negative MDA-MB-468 breast cancer cells. However, it showed excellent selectivity against the cancer cell line when compared to its effects on non-cancer cells. Furthermore, thailandine (2) showed excellent anti-plasmodial activity against both chloroquine-susceptible 3D7 and chloroquine-resistant W2 Plasmodium falciparum strains. The structure-activity relationship of isolated compound was also discussed in this study. The results of this study support the traditional use of Stephania dielsiana Y.C. Wu and the lead molecules identified can be further optimized for the development of highly effective and safe anti-cancer and anti-plasmodial drugs.
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11
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Davis SN, Wu P, Camci ED, Simon JA, Rubel EW, Raible DW. Chloroquine kills hair cells in zebrafish lateral line and murine cochlear cultures: Implications for ototoxicity. Hear Res 2020; 395:108019. [PMID: 32768772 PMCID: PMC7345387 DOI: 10.1016/j.heares.2020.108019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/08/2020] [Accepted: 06/10/2020] [Indexed: 02/09/2023]
Abstract
Hearing and balance deficits have been reported during and following treatment with the antimalarial drug chloroquine. However, experimental work examining the direct actions of chloroquine on mechanoreceptive hair cells in common experimental models is lacking. This study examines the effects of chloroquine on hair cells using two common experimental models: the zebrafish lateral line and neonatal mouse cochlear cultures. Zebrafish larvae were exposed to varying concentrations of chloroquine phosphate or hydroxychloroquine for 1 h or 24 h, and hair cells assessed by antibody staining. A significant, dose-dependent reduction in the number of surviving hair cells was seen across conditions for both exposure periods. Hydroxychloroquine showed similar toxicity. In mouse cochlear cultures, chloroquine damage was specific to outer hair cells in tissue from the cochlear basal turn, consistent with susceptibility to other ototoxic agents. These findings suggest a need for future studies employing hearing and balance monitoring during exposure to chloroquine and related compounds, particularly with interest in these compounds as therapeutics against viral infections including coronavirus.
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Affiliation(s)
- Samantha N Davis
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA; Department of Speech and Hearing Sciences, University of Washington, Seattle, WA, USA
| | - Patricia Wu
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA; Department of Biological Structure, University of Washington, Seattle, WA, USA
| | - Esra D Camci
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA; Department of Otolaryngology - Head and Neck Surgery, University of Washington, Seattle, WA, USA
| | - Julian A Simon
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA; Fred Hutch Cancer Research Center, Seattle, WA, USA
| | - Edwin W Rubel
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA
| | - David W Raible
- Virginial Merrill Bloedel Hearing Research Center, University of Washington, Seattle, WA, USA; Department of Biological Structure, University of Washington, Seattle, WA, USA.
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Siddiqui AA, Saha D, Iqbal MS, Saha SJ, Sarkar S, Banerjee C, Nag S, Mazumder S, De R, Pramanik S, Debsharma S, Bandyopadhyay U. Rab7 of Plasmodium falciparum is involved in its retromer complex assembly near the digestive vacuole. Biochim Biophys Acta Gen Subj 2020; 1864:129656. [PMID: 32512169 DOI: 10.1016/j.bbagen.2020.129656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 04/22/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Intracellular protein trafficking is crucial for survival of cell and proper functioning of the organelles; however, these pathways are not well studied in the malaria parasite. Its unique cellular architecture and organellar composition raise an interesting question to investigate. METHODS The interaction of Plasmodium falciparum Rab7 (PfRab7) with vacuolar protein sorting-associated protein 26 (PfVPS26) of retromer complex was shown by coimmunoprecipitation (co-IP). Confocal microscopy was used to show the localization of the complex in the parasite with respect to different organelles. Further chemical tools were employed to explore the role of digestive vacuole (DV) in retromer trafficking in parasite and GTPase activity of PfRab7 was examined. RESULTS PfRab7 was found to be interacting with retromer complex that assembled mostly near DV and the Golgi in trophozoites. Chemical disruption of DV by chloroquine (CQ) led to its disassembly that was further validated by using compound 5f, a heme polymerization inhibitor in the DV. PfRab7 exhibited Mg2+ dependent weak GTPase activity that was inhibited by a specific Rab7 GTPase inhibitor, CID 1067700, which prevented the assembly of retromer complex in P. falciparum and inhibited its growth suggesting the role of GTPase activity of PfRab7 in retromer assembly. CONCLUSION Retromer complex was found to be interacting with PfRab7 and the functional integrity of the DV was found to be important for retromer assembly in P. falciparum. GENERAL SIGNIFICANCE This study explores the retromer trafficking in P. falciparum and describes amechanism to validate DV targeting antiplasmodial molecules.
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Affiliation(s)
- Asim Azhar Siddiqui
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Debanjan Saha
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Mohd Shameel Iqbal
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Shubhra Jyoti Saha
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Souvik Sarkar
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Chinmoy Banerjee
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Shiladitya Nag
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Somnath Mazumder
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Rudranil De
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Saikat Pramanik
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Subhashis Debsharma
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India
| | - Uday Bandyopadhyay
- Division of Infectious Diseases and Immunology, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, West Bengal, India.
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Uzun T, Toptas O. Artesunate: could be an alternative drug to chloroquine in COVID-19 treatment? Chin Med 2020; 15:54. [PMID: 32514287 PMCID: PMC7254722 DOI: 10.1186/s13020-020-00336-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 05/21/2020] [Indexed: 12/15/2022] Open
Abstract
SARS (Severe Acute Respiratory Syndrome Coronavirus)-CV-2 (2019-nCov), which showed up in China in December 2019 and spread all over the world, has becomed a serious health problem. An effective, safe and proven treatment has not yet been found. Chloroquine has been recommended by some authors to be used for the treatment of patients infected with this virus however chloroquine may have side effects and drug resistance problems. Artesunate is a semisynthetic derivative of artemisinin, an antimalarial drug. Artesunate was thought to be an effective treatment for covid-19 because of its anti-inflammatory activity, NF-κB (nuclear Factor kappa B)-coronavirus effect and chloroquine-like endocytosis inhibition mechanism.
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Affiliation(s)
- Tuğçenur Uzun
- Department of Oral and Maxillofacial Surgery, Trabzon Oral and Dental Health Hospital, DDS, Trabzon, Turkey
| | - Orcun Toptas
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Abant Izzet Baysal University, Bolu, Turkey
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14
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Aktaş İ, Özmen Ö, Tutun H, Yalçın A, Türk A. Artemisinin attenuates doxorubicin induced cardiotoxicity and hepatotoxicity in rats. Biotech Histochem 2019; 95:121-128. [DOI: 10.1080/10520295.2019.1647457] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Affiliation(s)
- İ. Aktaş
- Vocational School of Health Services, Adıyaman University, Adıyaman, Turkey
| | - Ö. Özmen
- Faculty of Veterinary Medicine, Department of Pathology, Burdur Mehmet Akif Ersoy University, Burdur, Turkey
| | - H. Tutun
- Faculty of Veterinary Medicine, Department of Pharmacology and Toxicology, Burdur Mehmet Akif Ersoy University, Burdur, Turkey
| | - A. Yalçın
- Faculty of Medicine, Departments of Histology, Adıyaman University, Adıyaman, Turkey
| | - A. Türk
- Faculty of Medicine, Departments of Histology, Adıyaman University, Adıyaman, Turkey
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15
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Engwerda AHJ, Maassen R, Tinnemans P, Meekes H, Rutjes FPJT, Vlieg E. Attrition-Enhanced Deracemization of the Antimalaria Drug Mefloquine. Angew Chem Int Ed Engl 2018; 58:1670-1673. [PMID: 30508314 DOI: 10.1002/anie.201811289] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Indexed: 11/10/2022]
Abstract
Mefloquine is an important drug for prevention and treatment of malaria. It is commercially available as a racemic mixture, wherein only one enantiomer is active against malaria, while the other one causes severe psychotropic effects. By converting the drug into a compound that crystallizes as a racemizable racemic conglomerate, the deracemization of mefloquine into the desired enantiomer was achieved.
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Affiliation(s)
- Anthonius H J Engwerda
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
| | - Rick Maassen
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
| | - Paul Tinnemans
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
| | - Hugo Meekes
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
| | - Floris P J T Rutjes
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
| | - Elias Vlieg
- Institute for Molecules and Materials, Radboud University, Heyendaalseweg 135, 6525, AJ, Nijmegen, The Netherlands
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17
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Current and Future Use of Chloroquine and Hydroxychloroquine in Infectious, Immune, Neoplastic, and Neurological Diseases: A Mini-Review. Clin Drug Investig 2018; 38:653-671. [DOI: 10.1007/s40261-018-0656-y] [Citation(s) in RCA: 180] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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18
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Nyboer B, Heiss K, Mueller AK, Ingmundson A. The Plasmodium liver-stage parasitophorous vacuole: A front-line of communication between parasite and host. Int J Med Microbiol 2017; 308:107-117. [PMID: 28964681 DOI: 10.1016/j.ijmm.2017.09.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/19/2017] [Accepted: 09/11/2017] [Indexed: 12/13/2022] Open
Abstract
The intracellular development and differentiation of the Plasmodium parasite in the host liver is a prerequisite for the actual onset of malaria disease pathology. Since liver-stage infection is clinically silent and can be completely eliminated by sterilizing immune responses, it is a promising target for urgently needed innovative antimalarial drugs and/or vaccines. Discovered more than 65 years ago, these stages remain poorly understood regarding their molecular repertoire and interaction with their host cells in comparison to the pathogenic erythrocytic stages. The differentiating and replicative intrahepatic parasite resides in a membranous compartment called the parasitophorous vacuole, separating it from the host-cell cytoplasm. Here we outline seminal work that contributed to our present understanding of the fundamental dynamic cellular processes of the intrahepatic malarial parasite with both specific host-cell factors and compartments.
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Affiliation(s)
- Britta Nyboer
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany
| | - Kirsten Heiss
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany
| | - Ann-Kristin Mueller
- Centre for Infectious Diseases, Parasitology, University Hospital Heidelberg, Im Neuenheimer Feld 324, 69120 Heidelberg, Germany; Centre for Infection Research (DZIF), D 69120 Heidelberg, Germany,.
| | - Alyssa Ingmundson
- Department of Molecular Parasitology, Institute of Biology, Humboldt University Berlin, Philippstrasse 13, 10115 Berlin, Germany.
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19
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The pharmacological activities and mechanisms of artemisinin and its derivatives: a systematic review. Med Chem Res 2017. [DOI: 10.1007/s00044-016-1778-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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20
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Parallel inhibition of amino acid efflux and growth of erythrocytic Plasmodium falciparum by mefloquine and non-piperidine analogs: Implication for the mechanism of antimalarial action. Bioorg Med Chem Lett 2016; 26:4846-4850. [DOI: 10.1016/j.bmcl.2016.08.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 08/01/2016] [Accepted: 08/02/2016] [Indexed: 11/18/2022]
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21
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Mefloquine induces ROS mediated programmed cell death in malaria parasite: Plasmodium. Apoptosis 2016; 21:955-64. [DOI: 10.1007/s10495-016-1265-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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22
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Tilley L, Straimer J, Gnädig NF, Ralph SA, Fidock DA. Artemisinin Action and Resistance in Plasmodium falciparum. Trends Parasitol 2016; 32:682-696. [PMID: 27289273 DOI: 10.1016/j.pt.2016.05.010] [Citation(s) in RCA: 206] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 05/10/2016] [Accepted: 05/13/2016] [Indexed: 12/16/2022]
Abstract
The worldwide use of artemisinin-based combination therapies (ACTs) has contributed in recent years to a substantial reduction in deaths resulting from Plasmodium falciparum malaria. Resistance to artemisinins, however, has emerged in Southeast Asia. Clinically, resistance is defined as a slower rate of parasite clearance in patients treated with an artemisinin derivative or an ACT. These slow clearance rates associate with enhanced survival rates of ring-stage parasites briefly exposed in vitro to dihydroartemisinin. We describe recent progress made in defining the molecular basis of artemisinin resistance, which has identified a primary role for the P. falciparum K13 protein. Using K13 mutations as molecular markers, epidemiological studies are now tracking the emergence and spread of artemisinin resistance. Mechanistic studies suggest potential ways to overcome resistance.
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Affiliation(s)
- Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia.
| | - Judith Straimer
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Nina F Gnädig
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Australia
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University College of Physicians and Surgeons, New York, NY, USA; Division of Infectious Diseases, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA.
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Raphemot R, Posfai D, Derbyshire ER. Current therapies and future possibilities for drug development against liver-stage malaria. J Clin Invest 2016; 126:2013-20. [PMID: 27249674 DOI: 10.1172/jci82981] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Malaria remains a global public health threat, with half of the world's population at risk. Despite numerous efforts in the past decade to develop new antimalarial drugs to surmount increasing resistance to common therapies, challenges remain in the expansion of the current antimalarial arsenal for the elimination of this disease. The requirement of prophylactic and radical cure activities for the next generation of antimalarial drugs demands that new research models be developed to support the investigation of the elusive liver stage of the malaria parasite. In this Review, we revisit current antimalarial therapies and discuss recent advances for in vitro and in vivo malaria research models of the liver stage and their importance in probing parasite biology and the discovery of novel drug candidates.
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24
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Dalal S, Klemba M. Amino acid efflux by asexual blood-stage Plasmodium falciparum and its utility in interrogating the kinetics of hemoglobin endocytosis and catabolism in vivo. Mol Biochem Parasitol 2015. [PMID: 26215764 DOI: 10.1016/j.molbiopara.2015.07.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The endocytosis and catabolism of large quantities of host cell hemoglobin is a hallmark of the intraerythrocytic asexual stage of the human malaria parasite Plasmodium falciparum. It is known that the parasite's production of amino acids from hemoglobin far exceeds its metabolic needs. Here, we show that P. falciparum effluxes large quantities of certain non-polar (Ala, Leu, Val, Pro, Phe, Gly) and polar (Ser, Thr, His) amino acids to the external medium. That these amino acids originate from hemoglobin catabolism is indicated by the strong correlation between individual amino acid efflux rates and their abundances in hemoglobin, and the ability of the food vacuole falcipain inhibitor E-64d to greatly suppress efflux rates. We then developed a rapid, sensitive and precise method for quantifying flux through the hemoglobin endocytic-catabolic pathway that is based on leucine efflux. Optimization of the method involved the generation of a novel amino acid-restricted RPMI formulation as well as the validation of D-norvaline as an internal standard. The utility of this method was demonstrated by characterizing the effects of the phosphatidylinositol-3-kinase inhibitors wortmannin and dihydroartemisinin on the kinetics of Leu efflux. Both compounds rapidly inhibited Leu efflux, which is consistent with a role for phosphtidylinositol-3-phosphate production in the delivery of hemoglobin to the food vacuole; however, wortmannin inhibition was transient, which was likely due to the instability of this compound in culture medium. The simplicity, convenience and non-invasive nature of the Leu efflux assay described here makes it ideal for characterizing the in vivo kinetics of hemoglobin endocytosis and catabolism, for inhibitor target validation studies, and for medium-throughput screens to identify novel inhibitors of cytostomal endocytosis.
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Affiliation(s)
- Seema Dalal
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA
| | - Michael Klemba
- Department of Biochemistry, Virginia Tech, Blacksburg, VA 24061, USA.
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25
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van der Velden M, Rijpma SR, Russel FGM, Sauerwein RW, Koenderink JB. PfMDR2 and PfMDR5 are dispensable for Plasmodium falciparum asexual parasite multiplication but change in vitro susceptibility to anti-malarial drugs. Malar J 2015; 14:76. [PMID: 25884516 PMCID: PMC4350286 DOI: 10.1186/s12936-015-0581-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/25/2015] [Indexed: 01/09/2023] Open
Abstract
Background Membrane-associated ATP binding cassette (ABC) transport proteins hydrolyze ATP in order to translocate a broad spectrum of substrates, from single ions to macromolecules across membranes. In humans, members from this transport family have been linked to drug resistance phenotypes, e.g., tumour resistance by enhanced export of chemotherapeutic agents from cancer cells due to gene amplifications or polymorphisms in multidrug resistance (MDR) protein 1. Similar mechanisms have linked the Plasmodium falciparum PfMDR1 transporter to anti-malarial drug resistance acquisition. In this study, the possible involvement of two related MDR proteins, PfMDR2 and PfMDR5, to emerging drug resistance is investigated by a reverse genetics approach. Methods A homologous double crossover strategy was used to generate P. falciparum parasites lacking the Pfmdr2 (PfΔmdr2) or Pfmdr5 (PfΔmdr5) gene. Plasmodium lactate dehydrogenase activity was used as read-out for sensitivity to artemisinin (ART), atovaquone (ATO), dihydroartemisinin (DHA), chloroquine (CQ), lumefantrine (LUM), mefloquine (MQ), and quinine (QN). Differences in half maximal inhibitory concentration (IC50) values between wild type and each mutant line were determined using a paired t-test. Results Both PfΔmdr2 and PfΔmdr5 clones were capable of asexual multiplication. Upon drug exposure, PfΔmdr2 showed a marginally decreased sensitivity to ATO (IC50 of 1.2 nM to 1.8 nM), MQ (124 nM to 185 nM) and QN (40 nM to 70 nM), as compared to wild type (NF54) parasites. On the other hand, PfΔmdr5 showed slightly increased sensitivity to ART (IC50 of 26 nM to 19 nM). Conclusion Both Pfmdr2 and Pfmdr5 are dispensable for blood stage development while the deletion lines show altered sensitivity profiles to commonly used anti-malarial drugs. The findings show for the first time that next to PfMDR2, the PfMDR5 transport protein could play a role in emerging drug resistance. Electronic supplementary material The online version of this article (doi:10.1186/s12936-015-0581-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maarten van der Velden
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Sanna R Rijpma
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Frans G M Russel
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Robert W Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.
| | - Jan B Koenderink
- Department of Pharmacology and Toxicology, Radboud University Medical Center, Nijmegen, The Netherlands.
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Abstract
Recent initiatives to develop more effective and affordable drugs, controlling mosquitoes and development of a preventative vaccine have been launched with the goal of completely eradicating malaria. To this end, Novartis (Surrey, UK) and GlaxoSmithKline (Middlesex, UK) screened their chemical libraries of approximately two million small molecules for antimalarial properties, which resulted in a set of over 20,000 'highly druggable' initial hits. Efforts in academia are centered on specific pathway targets. One such high-throughput screening effort has been focused on hemozoin formation, a unique heme detoxification pathway found in the malaria parasite. This review discusses the current approaches and limitations of high-throughput screening discovery of hemozoin inhibitors. In the future, new methods must be developed to validate the mechanism of action of these hit compounds within the parasite.
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Egan TJ, Kuter D. Dual-functioning antimalarials that inhibit the chloroquine-resistance transporter. Future Microbiol 2013; 8:475-89. [PMID: 23534360 PMCID: PMC7099626 DOI: 10.2217/fmb.13.18] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Malaria remains a major international health challenge. Resistance to a number of existing drugs and evidence of the emergence of artemisinin resistance has emphasized the need for new antimalarials. A new approach has been the preparation of dual-function compounds that include a chloroquine-like antimalarial group and a group that resembles a chloroquine chemosensitizer. This article reviews the recent discovery of such dual-function antimalarials that are proposed to target both hemozoin formation and the chloroquine resistance transporter, PfCRT. These are discussed in relation to the mechanism of action of 4-aminoquinolines, chloroquine resistance and resistance reversal.
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Affiliation(s)
- Timothy J Egan
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa.
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28
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Hain AUP, Bosch J. Autophagy in Plasmodium, a multifunctional pathway? Comput Struct Biotechnol J 2013; 8:e201308002. [PMID: 24688742 PMCID: PMC3962217 DOI: 10.5936/csbj.201308002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/18/2013] [Accepted: 07/24/2013] [Indexed: 11/23/2022] Open
Abstract
Autophagy is a catabolic process that normally utilizes the lysosome. The far-reaching implications of this system in disease are being increasingly understood. Studying autophagy is complicated by its role in cell survival and programmed cell death and the involvement of the canonical marker of autophagy, Atg8/LC3, in numerous non-autophagic roles. The malaria parasite, Plasmodium, has conserved certain aspects of the autophagic machinery but for what purpose has long remained a mystery. Major advances have recently been gained and suggest a role for Atg8 in apicoplast maintenance, degradation of heme inside the food vacuole, and possibly trafficking of proteins or organelles outside the parasite membrane. Autophagy may also participate in programmed cell death under drug treatment or as a selective tool to limit parasite load. We review the current findings and discuss discrepancies in the field of autophagy in the Plasmodium parasite.
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Affiliation(s)
- Adelaide U P Hain
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, United States
| | - Jürgen Bosch
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins Malaria Research Institute, Baltimore, MD 21205, United States
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Henriques G, Martinelli A, Rodrigues L, Modrzynska K, Fawcett R, Houston DR, Borges ST, d'Alessandro U, Tinto H, Karema C, Hunt P, Cravo P. Artemisinin resistance in rodent malaria--mutation in the AP2 adaptor μ-chain suggests involvement of endocytosis and membrane protein trafficking. Malar J 2013; 12:118. [PMID: 23561245 PMCID: PMC3655824 DOI: 10.1186/1475-2875-12-118] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 02/26/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The control of malaria, caused by Plasmodium falciparum, is hampered by the relentless evolution of drug resistance. Because artemisinin derivatives are now used in the most effective anti-malarial therapy, resistance to artemisinin would be catastrophic. Indeed, studies suggest that artemisinin resistance has already appeared in natural infections. Understanding the mechanisms of resistance would help to prolong the effective lifetime of these drugs. Genetic markers of resistance are therefore required urgently. Previously, a mutation in a de-ubiquitinating enzyme was shown to confer artemisinin resistance in the rodent malaria parasite Plasmodium chabaudi. METHODS Here, for a mutant P. chabaudi malaria parasite and its immediate progenitor, the in vivo artemisinin resistance phenotypes and the mutations arising using Illumina whole-genome re-sequencing were compared. RESULTS An increased artemisinin resistance phenotype is accompanied by one non-synonymous substitution. The mutated gene encodes the μ-chain of the AP2 adaptor complex, a component of the endocytic machinery. Homology models indicate that the mutated residue interacts with a cargo recognition sequence. In natural infections of the human malaria parasite P. falciparum, 12 polymorphisms (nine SNPs and three indels) were identified in the orthologous gene. CONCLUSION An increased artemisinin-resistant phenotype occurs along with a mutation in a functional element of the AP2 adaptor protein complex. This suggests that endocytosis and trafficking of membrane proteins may be involved, generating new insights into possible mechanisms of resistance. The genotypes of this adaptor protein can be evaluated for its role in artemisinin responses in human infections of P. falciparum.
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Affiliation(s)
- Gisela Henriques
- Centro de Malaria & Doenças Tropicais,LA/IHMT/Universidade Nova de Lisboa, Lisbon, Portugal.
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30
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Abstract
Malaria continues to affect public health and economic growth in many regions of the world. The number of infections continues to rise and is associated with increased mortality, despite basic science and public health efforts. Drug therapy remains the mainstay of treatment and prevention of this disease. Plasmodium has a complex life cycle involving an arthropod vector and distinct stages within the human host. Each parasite stage plays a unique role in transmission, disease, and latency. These different stages may vary in their response to the various antimalarial compounds. This article will review antimalarial therapies and drug resistance in the context of the parasites' biology.
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Affiliation(s)
- Johanna P Daily
- Brigham and Women's Hospital, Infectious Disease, 75 Francis Street, Boston, MA 02115, USA
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Kasturi K, Mallika DS, Amos SJ, Venkateshaiah P, Rao KRSS. Current opinion on an emergence of drug resistant strains of Plasmodium falciparum through genetic alterations. Bioinformation 2012; 8:1114-8. [PMID: 23251047 PMCID: PMC3523227 DOI: 10.6026/97320630081114] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2012] [Revised: 09/05/2012] [Accepted: 10/17/2012] [Indexed: 11/23/2022] Open
Abstract
The human malarial parasite Plasmodium falciparum is one of the world's most devastating pathogen. Its capability to regulate its genes under various stages of its life cycle as well as under unfavourable environmental conditions has led to the development of vaccine resistant strains. Similarly, under drug pressure it develops mutations in the target genes. These mutations confer mid and high-level resistance to the antimalarial drugs. Increasing a resistance of malaria parasites to conventional antimalarial drugs is an important factor contributing to the persistence of the disease as a major health threat. This article reviews current knowledge of stage specific malarial targets, antimalarial drugs and the mutations that have led to the emergence of resistant strains.
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Affiliation(s)
- Kondapalli Kasturi
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
| | - Donepudi Siva Mallika
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
| | - Seelam Jeevan Amos
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
| | - Pavithra Venkateshaiah
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
| | - KRS Sambasiva Rao
- Department of Biotechnology, Acharya Nagarjuna University, Guntur, Andhra Pradesh, India
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Lelièvre J, Almela MJ, Lozano S, Miguel C, Franco V, Leroy D, Herreros E. Activity of clinically relevant antimalarial drugs on Plasmodium falciparum mature gametocytes in an ATP bioluminescence "transmission blocking" assay. PLoS One 2012; 7:e35019. [PMID: 22514702 PMCID: PMC3325938 DOI: 10.1371/journal.pone.0035019] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 03/08/2012] [Indexed: 01/12/2023] Open
Abstract
Background Current anti-malarial drugs have been selected on the basis of their activity against the symptom-causing asexual blood stage of the parasite. Which of these drugs also target gametocytes, in the sexual stage responsible for disease transmission, remains unknown. Blocking transmission is one of the main strategies in the eradication agenda and requires the identification of new molecules that are active against gametocytes. However, to date, the main limitation for measuring the effect of molecules against mature gametocytes on a large scale is the lack of a standardized and reliable method. Here we provide an efficient method to produce and purify mature gametocytes in vitro. Based on this new procedure, we developed a robust, affordable, and sensitive ATP bioluminescence-based assay. We then assessed the activity of 17 gold-standard anti-malarial drugs on Plasmodium late stage gametocytes. Methods and Findings Difficulties in producing large amounts of gametocytes have limited progress in the development of malaria transmission blocking assays. We improved the method established by Ifediba and Vanderberg to obtain viable, mature gametocytes en masse, whatever the strain used. We designed an assay to determine the activity of antimalarial drugs based on the intracellular ATP content of purified stage IV–V gametocytes after 48 h of drug exposure in 96/384-well microplates. Measurements of drug activity on asexual stages and cytotoxicity on HepG2 cells were also obtained to estimate the specificity of the active drugs. Conclusions The work described here represents another significant step towards determination of the activity of new molecules on mature gametocytes of any strain with an automated assay suitable for medium/high-throughput screening. Considering that the biology of the forms involved in the sexual and asexual stages is very different, a screen of our 2 million-compound library may allow us to discover novel anti-malarial drugs to target gametocyte-specific metabolic pathways.
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Affiliation(s)
- Joël Lelièvre
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
- * E-mail: (JL); (EH)
| | - Maria Jesus Almela
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
| | - Sonia Lozano
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
| | - Celia Miguel
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
| | - Virginia Franco
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Esperanza Herreros
- GlaxoSmithKline R&D, Tres Cantos Medicine Development Campus, Malaria Discovery Performance Unit, Madrid, Spain
- * E-mail: (JL); (EH)
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Kritsiriwuthinan K, Chaotheing S, Shaw PJ, Wongsombat C, Chavalitshewinkoon-Petmitr P, Kamchonwongpaisan S. Global gene expression profiling of Plasmodium falciparum in response to the anti-malarial drug pyronaridine. Malar J 2011; 10:242. [PMID: 21849091 PMCID: PMC3224238 DOI: 10.1186/1475-2875-10-242] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 08/18/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pyronaridine (PN) and chloroquine (CQ) are structurally related anti-malarial drugs with primarily the same mode of action. However, PN is effective against several multidrug-resistant lines of Plasmodium falciparum, including CQ resistant lines, suggestive of important operational differences between the two drugs. METHODS Synchronized trophozoite stage cultures of P. falciparum strain K1 (CQ resistant) were exposed to 50% inhibitory concentrations (IC50) of PN and CQ, and parasites were harvested from culture after 4 and 24 hours exposure. Global transcriptional changes effected by drug treatment were investigated using DNA microarrays. RESULTS After a 4 h drug exposure, PN induced a greater degree of transcriptional perturbation (61 differentially expressed features) than CQ (10 features). More genes were found to respond to 24 h treatments with both drugs, and 461 features were found to be significantly responsive to one or both drugs across all treatment conditions. Filtering was employed to remove features unrelated to primary drug action, specifically features representing genes developmentally regulated, secondary stress/death related processes and sexual stage development. The only significant gene ontologies represented among the 46 remaining features after filtering relate to host exported proteins from multi-gene families. CONCLUSIONS The malaria parasite's molecular responses to PN and CQ treatment are similar in terms of the genes and pathways affected. However, PN appears to exert a more rapid response than CQ. The faster action of PN may explain why PN is more efficacious than CQ, particularly against CQ resistant isolates. In agreement with several other microarray studies of drug action on the parasite, it is not possible, however, to discern mechanism of drug action from the drug-responsive genes.
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Affiliation(s)
- Kanyanan Kritsiriwuthinan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand
- Department of Protozoology, Faculty of Tropical Medicine, Mahidol University, Bangkok 10400, Thailand
| | - Sastra Chaotheing
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand
| | - Philip J Shaw
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand
| | - Chayaphat Wongsombat
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand
| | | | - Sumalee Kamchonwongpaisan
- National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Thailand Science Park, Pathumthani 12120, Thailand
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Artemisinin activity against Plasmodium falciparum requires hemoglobin uptake and digestion. Proc Natl Acad Sci U S A 2011; 108:11405-10. [PMID: 21709259 DOI: 10.1073/pnas.1104063108] [Citation(s) in RCA: 248] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Combination regimens that include artemisinin derivatives are recommended as first line antimalarials in most countries where malaria is endemic. However, the mechanism of action of artemisinin is not fully understood and the usefulness of this drug class is threatened by reports of decreased parasite sensitivity. We treated Plasmodium falciparum for periods of a few hours to mimic clinical exposure to the short half-life artemisinins. We found that drug treatment retards parasite growth and inhibits uptake of hemoglobin, even at sublethal concentrations. We show that potent artemisinin activity is dependent on hemoglobin digestion by the parasite. Inhibition of hemoglobinase activity with cysteine protease inhibitors, knockout of the cysteine protease falcipain-2 by gene deletion, or direct deprivation of host cell lysate, significantly decreases artemisinin sensitivity. Hemoglobin digestion is also required for artemisinin-induced exacerbation of oxidative stress in the parasite cytoplasm. Arrest of hemoglobin digestion by early stage parasites provides a mechanism for surviving short-term artemisinin exposure. These insights will help in the design of new drugs and new treatment strategies to circumvent drug resistance.
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Feng TS, Guantai EM, Nell M, van Rensburg CEJ, Ncokazi K, Egan TJ, Hoppe HC, Chibale K. Effects of highly active novel artemisinin-chloroquinoline hybrid compounds on β-hematin formation, parasite morphology and endocytosis in Plasmodium falciparum. Biochem Pharmacol 2011; 82:236-47. [PMID: 21596024 DOI: 10.1016/j.bcp.2011.04.018] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 04/27/2011] [Accepted: 04/29/2011] [Indexed: 11/25/2022]
Abstract
4-Aminoquinolines were hybridized with artemisinin and 1,4-naphthoquinone derivatives via the Ugi-four-component condensation reaction, and their biological activities investigated. The artemisinin-containing compounds 6a-c and its salt 6c-citrate were the most active target compounds in the antiplasmodial assays. However, despite the potent in vitro activities, they also displayed cytotoxicity against a mammalian cell-line, and had lower therapeutic indices than chloroquine. Morphological changes in parasites treated with these artemisinin-containing hybrid compounds were similar to those observed after addition of artemisinin. These hybrid compounds appeared to share mechanism(s) of action with both chloroquine and artemisinin: they exhibited potent β-hematin inhibitory activities; they caused an increase in accumulation of hemoglobin within the parasites that was intermediate between the increase observed with artesunate and chloroquine; and they also appeared to inhibit endocytosis as suggested by the decrease in the number of transport vesicles in the parasites. No cross-resistance with chloroquine was observed for these hybrid compounds, despite the fact that they contained the chloroquinoline moiety. The hybridization strategy therefore appeared to be borrowing the best from both classes of antimalarials.
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Affiliation(s)
- Tzu-Shean Feng
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa
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Valderramos SG, Scanfeld D, Uhlemann AC, Fidock DA, Krishna S. Investigations into the role of the Plasmodium falciparum SERCA (PfATP6) L263E mutation in artemisinin action and resistance. Antimicrob Agents Chemother 2010; 54:3842-52. [PMID: 20566762 PMCID: PMC2935017 DOI: 10.1128/aac.00121-10] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 02/17/2010] [Accepted: 06/07/2010] [Indexed: 11/20/2022] Open
Abstract
Artemisinin-based combination therapies (ACTs) are highly effective for the treatment of Plasmodium falciparum malaria, yet their sustained efficacy is threatened by the potential spread of parasite resistance. Recent studies have provided evidence that artemisinins can inhibit the function of PfATP6, the P. falciparum ortholog of the ER calcium pump SERCA, when expressed in Xenopus laevis oocytes. Inhibition was significantly reduced in an L263E variant, which introduced the mammalian residue into a putative drug-binding pocket. To test the hypothesis that this single mutation could decrease P. falciparum susceptibility to artemisinins, we implemented an allelic-exchange strategy to replace the wild-type pfatp6 allele by a variant allele encoding L263E. Transfected P. falciparum clones were screened by PCR analysis for disruption of the endogenous locus and introduction of the mutant L263E allele under the transcriptional control of a calmodulin promoter. Expression of the mutant allele was demonstrated by reverse transcriptase (RT) PCR and verified by sequence analysis. Parasite clones expressing wild-type or L263E variant PfATP6 showed no significant difference in 50% inhibitory concentrations (IC(50)s) for artemisinin or its derivatives dihydroartemisinin and artesunate. Nonetheless, hierarchical clustering analysis revealed a trend toward reduced susceptibility that neared significance (artemisinin, P approximately = 0.1; dihydroartemisinin, P = 0.053 and P = 0.085; and artesunate, P = 0.082 and P = 0.162 for the D10 and 7G8 lines, respectively). Notable differences in the distribution of normalized IC(50)s provided evidence of decreased responsiveness to artemisinin and dihydroartemisinin (P = 0.02 for the D10 and 7G8 lines), but not to artesunate in parasites expressing mutant PfATP6.
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Affiliation(s)
- Stephanie Gaw Valderramos
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York 10032, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London, SW17 ORE, United Kingdom, Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York 10032, New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
| | - Daniel Scanfeld
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York 10032, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London, SW17 ORE, United Kingdom, Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York 10032, New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
| | - Anne-Catrin Uhlemann
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York 10032, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London, SW17 ORE, United Kingdom, Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York 10032, New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
| | - David A. Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York 10032, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London, SW17 ORE, United Kingdom, Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York 10032, New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
| | - Sanjeev Krishna
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York 10032, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, Division of Cellular and Molecular Medicine, Centre for Infection, St. George's University of London, London, SW17 ORE, United Kingdom, Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York 10032, New York Presbyterian Hospital, Columbia University Medical Center, New York, New York 10032
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Waknine-Grinberg JH, Hunt N, Bentura-Marciano A, McQuillan JA, Chan HW, Chan WC, Barenholz Y, Haynes RK, Golenser J. Artemisone effective against murine cerebral malaria. Malar J 2010; 9:227. [PMID: 20691118 PMCID: PMC2928250 DOI: 10.1186/1475-2875-9-227] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Accepted: 08/09/2010] [Indexed: 11/12/2022] Open
Abstract
Background Artemisinins are the newest class of drug approved for malaria treatment. Due to their unique mechanism of action, rapid effect on Plasmodium, and high efficacy in vivo, artemisinins have become essential components of malaria treatment. Administration of artemisinin derivatives in combination with other anti-plasmodials has become the first-line treatment for uncomplicated falciparum malaria. However, their efficiency in cases of cerebral malaria (CM) remains to be determined. Methods The efficacy of several artemisinin derivatives for treatment of experimental CM was evaluated in ICR or C57BL/6 mice infected by Plasmodium berghei ANKA. Both mouse strains serve as murine models for CM. Results Artemisone was the most efficient drug tested, and could prevent death even when administered at relatively late stages of cerebral pathogenesis. No parasite resistance to artemisone was detected in recrudescence. Co-administration of artemisone together with chloroquine was more effective than monotherapy with either drug, and led to complete cure. Artemiside was even more effective than artemisone, but this substance has yet to be submitted to preclinical toxicological evaluation. Conclusions Altogether, the results support the use of artemisone for combined therapy of CM.
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Affiliation(s)
- Judith H Waknine-Grinberg
- Department of Microbiology and Molecular Genetics, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel
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Cardi D, Pozza A, Arnou B, Marchal E, Clausen JD, Andersen JP, Krishna S, Møller JV, le Maire M, Jaxel C. Purified E255L mutant SERCA1a and purified PfATP6 are sensitive to SERCA-type inhibitors but insensitive to artemisinins. J Biol Chem 2010; 285:26406-16. [PMID: 20530490 PMCID: PMC2924071 DOI: 10.1074/jbc.m109.090340] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The antimalarial drugs artemisinins have been described as inhibiting Ca(2+)-ATPase activity of PfATP6 (Plasmodium falciparum ATP6) after expression in Xenopus oocytes. Mutation of an amino acid residue in mammalian SERCA1 (Glu(255)) to the equivalent one predicted in PfATP6 (Leu) was reported to induce sensitivity to artemisinin in the oocyte system. However, in the present experiments, we found that artemisinin did not inhibit mammalian SERCA1a E255L either when expressed in COS cells or after purification of the mutant expressed in Saccharomyces cerevisiae. Moreover, we found that PfATP6 after expression and purification from S. cerevisiae was insensitive to artemisinin and significantly less sensitive to thapsigargin and 2,5-di(tert-butyl)-1,4-benzohydroquinone than rabbit SERCA1 but retained higher sensitivity to cyclopiazonic acid, another type of SERCA1 inhibitor. Although mammalian SERCA and purified PfATP6 appear to have different pharmacological profiles, their insensitivity to artemisinins suggests that the mechanism of action of this class of drugs on the calcium metabolism in the intact cell is complex and cannot be ascribed to direct inhibition of PfATP6. Furthermore, the successful purification of PfATP6 affords the opportunity to develop new antimalarials by screening for inhibitors against PfATP6.
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Affiliation(s)
- Delphine Cardi
- Commissariat à l'Energie Atomique, Institut de Biologie et de Technologies de Saclay, SB2SM, France
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Min-Oo G, Ayi K, Bongfen SE, Tam M, Radovanovic I, Gauthier S, Santiago H, Rothfuchs AG, Roffê E, Sher A, Mullick A, Fortin A, Stevenson MM, Kain KC, Gros P. Cysteamine, the natural metabolite of pantetheinase, shows specific activity against Plasmodium. Exp Parasitol 2010; 125:315-24. [PMID: 20219464 DOI: 10.1016/j.exppara.2010.02.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Revised: 01/21/2010] [Accepted: 02/22/2010] [Indexed: 11/26/2022]
Abstract
In mice, loss of pantetheinase activity causes susceptibility to infection with Plasmodium chabaudi AS. Treatment of mice with the pantetheinase metabolite cysteamine reduces blood-stage replication of P. chabaudi and significantly increases survival. Similarly, a short exposure of Plasmodium to cysteamine ex vivo is sufficient to suppress parasite infectivity in vivo. This effect of cysteamine is specific and not observed with a related thiol (dimercaptosuccinic acid) or with the pantethine precursor of cysteamine. Also, cysteamine does not protect against infection with the parasite Trypanosoma cruzi or the fungal pathogen Candida albicans, suggesting cysteamine acts directly against the parasite and does not modulate host inflammatory response. Cysteamine exposure also blocks replication of P. falciparum in vitro; moreover, these treated parasites show higher levels of intact hemoglobin. This study highlights the in vivo action of cysteamine against Plasmodium and provides further evidence for the involvement of pantetheinase in host response to this infection.
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Affiliation(s)
- Gundula Min-Oo
- Department of Biochemistry, McGill University, 3655 Promenade Sir William Osler, Montréal, QC, Canada
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PfPI3K, a phosphatidylinositol-3 kinase from Plasmodium falciparum, is exported to the host erythrocyte and is involved in hemoglobin trafficking. Blood 2010; 115:2500-7. [PMID: 20093402 DOI: 10.1182/blood-2009-08-238972] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Polyphosphorylated phosphoinositides (PIPs) are potent second messengers, which trigger a wide variety of signaling and trafficking events in most eukaryotic cells. However, the role and metabolism of PIPs in malaria parasite Plasmodium have remained largely unexplored. Our present studies suggest that PfPI3K, a novel phosphatidylinositol-3-kinase (PI3K) in Plasmodium falciparum, is exported to the host erythrocyte by the parasite in an active form. PfPI3K is a versatile enzyme as it can generate various 3'-phosphorylated PIPs. In the parasite, PfPI3K was localized in vesicular compartments near the membrane and in its food vacuole. PI3K inhibitors wortmannin and LY294002 were effective against PfPI3K and were used to study PfPI3K function. We found that PfPI3K is involved in endocytosis from the host and trafficking of hemoglobin in the parasite. The inhibition of PfPI3K resulted in entrapment of hemoglobin in vesicles in the parasite cytoplasm, which prevented its transport to the food vacuole, the site of hemoglobin catabolism. As a result, hemoglobin digestion, which is a source of amino acids necessary for parasite growth, was attenuated and caused the inhibition of parasite growth.
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Abu Bakar N, Klonis N, Hanssen E, Chan C, Tilley L. Digestive-vacuole genesis and endocytic processes in the early intraerythrocytic stages of Plasmodium falciparum. J Cell Sci 2010; 123:441-50. [PMID: 20067995 DOI: 10.1242/jcs.061499] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The digestive vacuole of the malaria parasite Plasmodium falciparum is the site of haemoglobin digestion and haem detoxification, and is the target of chloroquine and other antimalarials. The mechanisms for genesis of the digestive vacuole and transfer of haemoglobin from the host cytoplasm are still debated. Here, we use live-cell imaging and photobleaching to monitor the uptake of the pH-sensitive fluorescent tracer SNARF-1-dextran from the erythrocyte cytoplasm in ring-stage and trophozoite-stage parasites. We compare these results with electron tomography of serial sections of parasites at different stages of growth. We show that uptake of erythrocyte cytoplasm is initiated in mid-ring-stage parasites. The host cytoplasm is internalised via cytostome-derived invaginations and concentrated into several acidified peripheral structures. Haemoglobin digestion and haemozoin formation take place in these vesicles. The ring-stage parasites can adopt a deeply invaginated cup shape but do not take up haemoglobin via macropinocytosis. As the parasite matures, the haemozoin-containing compartments coalesce to form a single acidic digestive vacuole that is fed by haemoglobin-containing vesicles. There is also evidence for haemoglobin degradation in compartments outside the digestive vacuole. The work has implications for the stage specificity of quinoline and endoperoxide antimalarials.
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Totino PRR, Daniel-Ribeiro CT, Ferreira-da-Cruz MDF. Pro-apoptotic effects of antimalarial drugs do not affect mature human erythrocytes. Acta Trop 2009; 112:236-8. [PMID: 19665984 DOI: 10.1016/j.actatropica.2009.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 07/31/2009] [Accepted: 08/03/2009] [Indexed: 10/20/2022]
Abstract
Malaria is an important public health problem worldwide, representing also an obstacle for the development of the countries, mainly in the African continent. Since no effective vaccine has been developed yet, early diagnosis and prompt treatment are the main strategy to control malaria transmission. Many of the drugs used for malaria treatment have the ability to induce apoptosis in different cell types. In addition, apoptosis has also been identified in enucleated cells. The present work is aimed, therefore, to evaluate the pro-apoptotic aptness of chloroquine, quinine, artemisinin and mefloquine on mature erythrocytes by flow cytometry through the detection of cell shrinkage and phosphatidylserine exposure at the cell surface-hallmarks of apoptosis. Although we observed that known apoptosis inducer, such as ionomycin, had led to erythrocyte apoptosis, we were not able to detect any pro-apoptotic effect of the studied antimalarial drugs on these cells. We conclude that chloroquine, quinine, artemisinin and mefloquine may not be able to induce apoptosis in erythrocytes and, therefore, do not seem to contribute to malaria associated erythrocyte destruction and anemia.
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Role of Plasmodium falciparum digestive vacuole plasmepsins in the specificity and antimalarial mode of action of cysteine and aspartic protease inhibitors. Antimicrob Agents Chemother 2009; 53:4968-78. [PMID: 19752273 DOI: 10.1128/aac.00882-09] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hemoglobin (Hb) degradation is essential for the growth of the intraerythrocytic stages of malarial parasites. This process, which occurs inside an acidic digestive vacuole (DV), is thought to involve the action of four aspartic proteases, termed plasmepsins (PMs). These enzymes have received considerable attention as potential antimalarial drug targets. Leveraging the availability of a set of PM-knockout lines generated in Plasmodium falciparum, we report here that a wide range of previously characterized or novel aspartic protease inhibitors exert their antimalarial activities independently of their effect on the DV PMs. We also assayed compounds previously shown to inhibit cysteine proteases residing in the DV. The most striking observation was a ninefold increase in the potency of the calpain inhibitor N-acetyl-leucinyl-leucinyl-norleucinal (ALLN) against parasites lacking all four DV PMs. Genetic ablation of PM III or PM IV also decreased the level of parasite resistance to the beta-hematin binding antimalarial chloroquine. On the basis of the findings of drug susceptibility and isobologram assays, as well as the findings of studies of the inhibition of Hb degradation, morphological analyses, and stage specificity, we conclude that the DV PMs and falcipain cysteine proteases act cooperatively in Hb hydrolysis. We also identify several aspartic protease inhibitors, designed to target DV PMs, which appear to act on alternative targets early in the intraerythrocytic life cycle. These include the potent diphenylurea compound GB-III-32, which was found to be fourfold less potent against a P. falciparum line overexpressing plasmepsin X than against the parental nontransformed parasite line. The identification of the mode of action of these inhibitors will be important for future antimalarial drug discovery efforts focusing on aspartic proteases.
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The malarial parasite Plasmodium falciparum imports the human protein peroxiredoxin 2 for peroxide detoxification. Proc Natl Acad Sci U S A 2009; 106:13323-8. [PMID: 19666612 DOI: 10.1073/pnas.0905387106] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Coevolution of the malarial parasite and its human host has resulted in a complex network of interactions contributing to the homeodynamics of the host-parasite unit. As a rapidly growing and multiplying organism, Plasmodium falciparum depends on an adequate antioxidant defense system that is efficient despite the absence of genuine catalase and glutathione peroxidase. Using different experimental approaches, we demonstrate that P. falciparum imports the human redox-active protein peroxiredoxin 2 (hPrx-2, hTPx1) into its cytosol. As shown by confocal microscopy and immunogold electron microscopy, hPrx-2 is also present in the Maurer's clefts, organelles that are described as being involved in parasite protein export. Enzyme kinetic analyses prove that hPrx-2 accepts Plasmodium cytosolic thioredoxin 1 as a reducing substrate. hPrx-2 accounts for roughly 50% of thioredoxin peroxidase activity in parasite extracts, thus indicating a functional role of hPrx-2 as an enzymatic scavenger of peroxides in the parasite. Under chloroquine treatment, a drug promoting oxidative stress, the abundance of hPrx-2 in the parasite increases significantly. P. falciparum has adapted to adopt the hPrx-2, thereby using the host protein for its own purposes.
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Ashcraft KA, Bonneau RH. Psychological stress exacerbates primary vaginal herpes simplex virus type 1 (HSV-1) infection by impairing both innate and adaptive immune responses. Brain Behav Immun 2008; 22:1231-40. [PMID: 18639627 PMCID: PMC3721735 DOI: 10.1016/j.bbi.2008.06.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2008] [Revised: 06/09/2008] [Accepted: 06/20/2008] [Indexed: 11/26/2022] Open
Abstract
Chronic psychological stress is generally immunosuppressive and contributes to an increase in herpes simplex virus (HSV) pathogenicity. We have previously shown that mice experiencing stress at the time of intranasal HSV infection have increased levels of infectious virus in their nasal cavity, as compared to control mice that were not subjected to stress. We have extended our studies to determine the effects of stress at another clinically-relevant mucosal site by examining the immune response to and pathogenesis of vaginal HSV infection. Mice experiencing psychological stress during vaginal HSV infection exhibited an increase in both vaginal viral titers and the pathology associated with this HSV infection. We demonstrate that these observations result from the failure of both the innate and HSV-specific adaptive immune responses. At 2 days post-infection, NK cell numbers were significantly decreased in mice experiencing restraint stress. Studies examining the adaptive immune response revealed a decrease in the number of HSV-specific CD8(+) T cells in not only the vaginal tissue itself but also the draining iliac lymph nodes (ILN). Furthermore, the number of functional cells, in terms of both their degranulation and interferon-gamma production, in the ILN of stressed mice was decreased as compared to non-stressed mice. We conclude that psychological stress, through its suppression of both innate and adaptive immune responses, may be an important factor in the ability to control vaginal HSV infection.
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Affiliation(s)
- Kathleen A. Ashcraft
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA
| | - Robert H. Bonneau
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA,Correspondence should be addressed to: Robert H. Bonneau, Ph.D., Department of Microbiology and Immunology (H107), The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, 500 University Drive, Hershey, Pennsylvania 17033, Telephone: 717-531-4078; Fax: 717-531-6522;
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Ashcraft KA, Hunzeker J, Bonneau RH. Psychological stress impairs the local CD8+ T cell response to mucosal HSV-1 infection and allows for increased pathogenicity via a glucocorticoid receptor-mediated mechanism. Psychoneuroendocrinology 2008; 33:951-63. [PMID: 18657369 PMCID: PMC3721759 DOI: 10.1016/j.psyneuen.2008.04.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2007] [Revised: 04/02/2008] [Accepted: 04/09/2008] [Indexed: 11/29/2022]
Abstract
Psychological stress and its associated increases in corticosterone are generally immunosuppressive and contribute to increased herpes simplex virus (HSV)-associated pathogenicity. However, the impact of stress on local control of the initial mucosal-based HSV infection has not been elucidated, nor have the ramifications of such failures of the immune response in terms of viral spread. To address these gaps in knowledge, the studies described herein sought to determine how psychological stress and associated increases in corticosterone may increase susceptibility to HSV encephalitis by allowing for increased viral titers at the site of initial infection. We have shown that in mice intranasally infected with HSV-1, a cell-mediated immune response occurs in the nasopharyngeal-associated lymphoid tissue (NALT), mediastinal lymph nodes (MLN), and superficial cervical lymph nodes (CLN). However, psychological stress induced by restraint decreased the number of lymphocytes in these tissues in HSV-infected mice. Surprisingly, the effects of this restraint stress on HSV-specific CTL function varied by immune tissue. Increased viral titers were found in the nasal cavity of stressed mice, an observation which correlated with an increased CD8+ cell response in the CLN. These findings led us to extend our studies to also determine the ramifications of decreased numbers of locally derived lymphocytes on viral titers following infection. Using an approach in which the NALT was surgically removed prior to infection, we confirmed that decreased numbers of NALT-derived lymphocytes at the time of infection allows for increased viral replication. We conclude that the increased viral titers observed in mice experiencing psychological stress are the consequence of a glucocorticoid-mediated reduction in the numbers of lymphocytes responsible for resolving the initial infection.
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MESH Headings
- Animals
- CD8-Positive T-Lymphocytes/immunology
- CD8-Positive T-Lymphocytes/physiology
- Cells, Cultured
- Corticosterone/physiology
- Down-Regulation/drug effects
- Down-Regulation/immunology
- Herpes Simplex/immunology
- Herpes Simplex/veterinary
- Herpesvirus 1, Human/immunology
- Herpesvirus 1, Human/pathogenicity
- Hormone Antagonists/pharmacology
- Immunity, Mucosal/immunology
- Immunity, Mucosal/physiology
- Lymphocyte Activation/immunology
- Lymphocytes/drug effects
- Lymphocytes/immunology
- Male
- Mice
- Mice, Inbred C57BL
- Mifepristone/pharmacology
- Receptors, Glucocorticoid/antagonists & inhibitors
- Receptors, Glucocorticoid/physiology
- Stress, Psychological/immunology
- Stress, Psychological/physiopathology
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Affiliation(s)
- Kathleen A. Ashcraft
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA
| | - John Hunzeker
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA
| | - Robert H. Bonneau
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033, USA
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Schlitzer M. Antimalarial drugs - what is in use and what is in the pipeline. Arch Pharm (Weinheim) 2008; 341:149-63. [PMID: 18297679 DOI: 10.1002/ardp.200700184] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Malaria continues to be a potentially fatal threat to almost half of the world's population. In light of this threat, the armory to fight this disease is rather limited. Resistance against the most common and affordable antimalarials is widespread. Only few new drugs are in clinical development, most of them belong to long used classes of antimalarial drugs. This review will concisely cover the drugs which are currently in use, and describe the drug candidates which are in clinical evaluation.
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Affiliation(s)
- Martin Schlitzer
- Philipps-Universität, Institut für Pharmazeutische Chemie, Marburg, Germany.
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Lazarus MD, Schneider TG, Taraschi TF. A new model for hemoglobin ingestion and transport by the human malaria parasite Plasmodium falciparum. J Cell Sci 2008; 121:1937-49. [PMID: 18477610 PMCID: PMC5105679 DOI: 10.1242/jcs.023150] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The current model for hemoglobin ingestion and transport by intraerythrocytic Plasmodium falciparum malaria parasites shares similarities with endocytosis. However, the model is largely hypothetical, and the mechanisms responsible for the ingestion and transport of host cell hemoglobin to the lysosome-like food vacuole (FV) of the parasite are poorly understood. Because actin dynamics play key roles in vesicle formation and transport in endocytosis, we used the actin-perturbing agents jasplakinolide and cytochalasin D to investigate the role of parasite actin in hemoglobin ingestion and transport to the FV. In addition, we tested the current hemoglobin trafficking model through extensive analysis of serial thin sections of parasitized erythrocytes (PE) by electron microscopy. We find that actin dynamics play multiple, important roles in the hemoglobin transport pathway, and that hemoglobin delivery to the FV via the cytostomes might be required for parasite survival. Evidence is provided for a new model, in which hemoglobin transport to the FV occurs by a vesicle-independent process.
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Affiliation(s)
- Michelle D. Lazarus
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Timothy G. Schneider
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Theodore F. Taraschi
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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de Villiers KA, Marques HM, Egan TJ. The crystal structure of halofantrine-ferriprotoporphyrin IX and the mechanism of action of arylmethanol antimalarials. J Inorg Biochem 2008; 102:1660-7. [PMID: 18508124 DOI: 10.1016/j.jinorgbio.2008.04.001] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 03/12/2008] [Accepted: 04/11/2008] [Indexed: 10/22/2022]
Abstract
The crystal structure of the complex formed between the antimalarial drug halofantrine and ferriprotoporphyrin IX (Fe(III)PPIX) has been determined by single crystal X-ray diffraction. The structure shows that halofantrine coordinates to the Fe(III) center through its alcohol functionality in addition to pi-stacking of the phenanthrene ring over the porphyrin. The length of the Fe(III)-O bond is consistent with an alkoxide and not an alcohol coordinating group. The iron porphyrin is five coordinate and monomeric. Changes in the electronic spectrum of Fe(III)PPIX upon addition of halofantrine base in acetonitrile solution are almost identical to those observed upon addition of quinidine free base in the same solvent. This suggests homologous binding. Molecular mechanics modeling of Fe(III)PPIX complexes of quinidine, quinine, 9-epiquinine and 9-epiquinidine based on this homology suggests that the antimalarially active quinidine and quinine can readily adopt conformations that permit formation of an intramolecular salt bridge between the protonated quinuclidine tertiary amino group and unprotonated heme propionate group, while the inactive epimers 9-epiquinidine and 9-epiquinine have to adopt high energy conformations in order to accommodate such salt bridge formation. We propose that salt bridge formation may interrupt formation of the hemozoin precursor dimer formed during the heme detoxification pathway and so account for the strong activity of the two active isomers.
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Affiliation(s)
- Katherine A de Villiers
- Department of Chemistry, University of Cape Town, Private Bag, Rondebosch 7701, South Africa
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Differential effects of quinoline antimalarials on endocytosis in Plasmodium falciparum. Antimicrob Agents Chemother 2008; 52:1840-2. [PMID: 18316523 DOI: 10.1128/aac.01478-07] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The effects of quinoline antimalarials on endocytosis by Plasmodium falciparum was investigated by measuring parasite hemoglobin levels, peroxidase uptake, and transport vesicle content. Mefloquine, quinine, and halofantrine inhibited endocytosis, and chloroquine inhibited vesicle trafficking, while amodiaquine shared both effects. Protease inhibitors moderated hemoglobin perturbations, suggesting a common role for heme binding.
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