1
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Elahi R, Prigge ST. New insights into apicoplast metabolism in blood-stage malaria parasites. Curr Opin Microbiol 2023; 71:102255. [PMID: 36563485 PMCID: PMC9852000 DOI: 10.1016/j.mib.2022.102255] [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: 10/03/2022] [Revised: 11/21/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022]
Abstract
The apicoplast of Plasmodium falciparum is the only source of essential isoprenoid precursors and Coenzyme A (CoA) in the parasite. Isoprenoid precursor synthesis relies on the iron-sulfur cluster (FeS) cofactors produced within the apicoplast, rendering FeS synthesis an essential function of this organelle. Recent reports provide important insights into the roles of FeS cofactors and the use of isoprenoid precursors and CoA both inside and outside the apicoplast. Here, we review the recent insights into the roles of these metabolites in blood-stage malaria parasites and discuss new questions that have been raised in light of these discoveries.
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Affiliation(s)
- Rubayet Elahi
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, MD, USA; The Johns Hopkins Malaria Research Institute, Baltimore, MD, USA
| | - Sean T Prigge
- Department of Molecular Microbiology and Immunology, Johns Hopkins University, Baltimore, MD, USA; The Johns Hopkins Malaria Research Institute, Baltimore, MD, USA.
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2
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Identification and Validation of Toxoplasma gondii Mitoribosomal Large Subunit Components. Microorganisms 2022; 10:microorganisms10050863. [PMID: 35630308 PMCID: PMC9145746 DOI: 10.3390/microorganisms10050863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 12/10/2022] Open
Abstract
Mitochondrial ribosomes are fundamental to mitochondrial function, and thus survival, of nearly all eukaryotes. Despite their common ancestry, mitoribosomes have evolved divergent features in different eukaryotic lineages. In apicomplexans, the mitochondrial rRNA is extremely fragmented raising questions about its evolution, protein composition and structure. Apicomplexan mitochondrial translation and the mitoribosomes are essential in all parasites and life stages studied, highlighting mitoribosomes as a promising target for drugs. Still, the apicomplexan mitoribosome is understudied, with one of the obstacles being that its composition is unknown. Here, to facilitate the study of apicomplexan mitoribosomes, we identified and validated components of the mitoribosomal large subunit in the model apicomplexan Toxoplasma gondii.
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3
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Pamukcu S, Cerutti A, Bordat Y, Hem S, Rofidal V, Besteiro S. Differential contribution of two organelles of endosymbiotic origin to iron-sulfur cluster synthesis and overall fitness in Toxoplasma. PLoS Pathog 2021; 17:e1010096. [PMID: 34793583 PMCID: PMC8639094 DOI: 10.1371/journal.ppat.1010096] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 12/02/2021] [Accepted: 11/05/2021] [Indexed: 11/21/2022] Open
Abstract
Iron-sulfur (Fe-S) clusters are one of the most ancient and ubiquitous prosthetic groups, and they are required by a variety of proteins involved in important metabolic processes. Apicomplexan parasites have inherited different plastidic and mitochondrial Fe-S clusters biosynthesis pathways through endosymbiosis. We have investigated the relative contributions of these pathways to the fitness of Toxoplasma gondii, an apicomplexan parasite causing disease in humans, by generating specific mutants. Phenotypic analysis and quantitative proteomics allowed us to highlight notable differences in these mutants. Both Fe-S cluster synthesis pathways are necessary for optimal parasite growth in vitro, but their disruption leads to markedly different fates: impairment of the plastidic pathway leads to a loss of the organelle and to parasite death, while disruption of the mitochondrial pathway trigger differentiation into a stress resistance stage. This highlights that otherwise similar biochemical pathways hosted by different sub-cellular compartments can have very different contributions to the biology of the parasites, which is something to consider when exploring novel strategies for therapeutic intervention.
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Affiliation(s)
| | - Aude Cerutti
- LPHI, Univ Montpellier, CNRS, Montpellier, France
| | - Yann Bordat
- LPHI, Univ Montpellier, CNRS, Montpellier, France
| | - Sonia Hem
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
| | - Valérie Rofidal
- BPMP, Univ Montpellier, CNRS, INRAE, Institut Agro, Montpellier, France
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4
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Smith NC, Goulart C, Hayward JA, Kupz A, Miller CM, van Dooren GG. Control of human toxoplasmosis. Int J Parasitol 2020; 51:95-121. [PMID: 33347832 DOI: 10.1016/j.ijpara.2020.11.001] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/12/2020] [Accepted: 11/15/2020] [Indexed: 12/21/2022]
Abstract
Toxoplasmosis is caused by Toxoplasma gondii, an apicomplexan parasite that is able to infect any nucleated cell in any warm-blooded animal. Toxoplasma gondii infects around 2 billion people and, whilst only a small percentage of infected people will suffer serious disease, the prevalence of the parasite makes it one of the most damaging zoonotic diseases in the world. Toxoplasmosis is a disease with multiple manifestations: it can cause a fatal encephalitis in immunosuppressed people; if first contracted during pregnancy, it can cause miscarriage or congenital defects in the neonate; and it can cause serious ocular disease, even in immunocompetent people. The disease has a complex epidemiology, being transmitted by ingestion of oocysts that are shed in the faeces of definitive feline hosts and contaminate water, soil and crops, or by consumption of intracellular cysts in undercooked meat from intermediate hosts. In this review we examine current and future approaches to control toxoplasmosis, which encompass a variety of measures that target different components of the life cycle of T. gondii. These include: education programs about the parasite and avoidance of contact with infectious stages; biosecurity and sanitation to ensure food and water safety; chemo- and immunotherapeutics to control active infections and disease; prophylactic options to prevent acquisition of infection by livestock and cyst formation in meat; and vaccines to prevent shedding of oocysts by definitive feline hosts.
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Affiliation(s)
- Nicholas C Smith
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; Research School of Biology, Australian National University, Canberra, ACT 0200, Australia.
| | - Cibelly Goulart
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia; Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Jenni A Hayward
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
| | - Andreas Kupz
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD 4878, Australia
| | - Catherine M Miller
- College of Public Health, Medical and Veterinary Science, James Cook University, Cairns, QLD 4878, Australia
| | - Giel G van Dooren
- Research School of Biology, Australian National University, Canberra, ACT 0200, Australia
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5
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Doshi K, Pandya N, Datt M. In silico assessment of natural products and approved drugs as potential inhibitory scaffolds targeting aminoacyl-tRNA synthetases from Plasmodium. 3 Biotech 2020; 10:470. [PMID: 33088666 DOI: 10.1007/s13205-020-02460-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/30/2020] [Indexed: 10/23/2022] Open
Abstract
Malaria remains the leading cause of deaths globally, despite significant advancement towards understanding its epidemiology and availability of multiple therapeutic interventions. Poor efficacy of the approved vaccine, and the rapid emergence of antimalarial drug resistance, warrants an urgent need to expedite the process of development of new lead molecules targeting malaria. Aminoacyl-tRNA synthetases (aaRSs) are essential enzymes crucial for ribosomal protein synthesis and are valid antimalarial targets. This study explores the prospects of (re-)positioning the repertoire of approved drugs and natural products as potential malarial aaRS inhibitors. Molecular docking of these two sets of small-molecules to lysyl-, prolyl-, and tyrosyl- synthetases from Plasmodium followed by a comparison of the top-ranking docked compounds against human homologs facilitated identification of promising molecular scaffolds. Raltitrexed and Cefprozil, an anticancer drug and an antibiotic, respectively, showed stronger binding to Plasmodium aaRSs compared to human homologs with > 4 kcal/mol difference in the docking scores. Similarly, a difference of ~ 3 kcal/mol in Glide scores was observed for docked Calcipotriol, a drug used for psoriasis treatment, against the two lysyl-tRNA synthetases. Natural products such as Dihydroxanthohumol and Betmidin, having aromatic rings as a substructure, showed preferential docking to the purine binding pocket in Plasmodium tyrosyl-tRNA synthetase as evident from the calculated change in binding free energies. We present detailed analyses of the calculated intermolecular interaction for all top-scoring docked poses. Overall, this study provides a compelling foundation to design and develop specific antimalarials.
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Affiliation(s)
- Ketki Doshi
- Biological and Life Sciences Division, School of Arts and Sciences, Ahmedabad University, Ahmedabad, Gujarat 380009 India
| | - Niyati Pandya
- Biological and Life Sciences Division, School of Arts and Sciences, Ahmedabad University, Ahmedabad, Gujarat 380009 India
| | - Manish Datt
- Biological and Life Sciences Division, School of Arts and Sciences, Ahmedabad University, Ahmedabad, Gujarat 380009 India
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6
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Baral B, Mozafari MR. Strategic Moves of "Superbugs" Against Available Chemical Scaffolds: Signaling, Regulation, and Challenges. ACS Pharmacol Transl Sci 2020; 3:373-400. [PMID: 32566906 PMCID: PMC7296549 DOI: 10.1021/acsptsci.0c00005] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Indexed: 12/12/2022]
Abstract
Superbugs' resistivity against available natural products has become an alarming global threat, causing a rapid deterioration in public health and claiming tens of thousands of lives yearly. Although the rapid discovery of small molecules from plant and microbial origin with enhanced bioactivity has provided us with some hope, a rapid hike in the resistivity of superbugs has proven to be the biggest therapeutic hurdle of all times. Moreover, several distinct mechanisms endowed by these notorious superbugs make them immune to these antibiotics subsequently causing our antibiotic wardrobe to be obsolete. In this unfortunate situation, though the time frame for discovering novel "hit molecules" down the line remains largely unknown, our small hope and untiring efforts injected in hunting novel chemical scaffolds with unique molecular targets using high-throughput technologies may safeguard us against these life-threatening challenges to some extent. Amid this crisis, the current comprehensive review highlights the present status of knowledge, our search for bacteria Achilles' heel, distinct molecular signaling that an opportunistic pathogen bestows to trespass the toxicity of antibiotics, and facile strategies and appealing therapeutic targets of novel drugs. Herein, we also discuss multidimensional strategies to combat antimicrobial resistance.
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Affiliation(s)
- Bikash Baral
- Department
of Biochemistry, University of Turku, Tykistökatu 6, Turku, Finland
| | - M. R. Mozafari
- Australasian
Nanoscience and Nanotechnology Initiative, 8054 Monash University LPO, Clayton, Victoria 3168, Australia
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7
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Messenger RNAs with large numbers of upstream open reading frames are translated via leaky scanning and reinitiation in the asexual stages of Plasmodium falciparum. Parasitology 2020; 147:1100-1113. [DOI: 10.1017/s0031182020000840] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AbstractThe genome of Plasmodium falciparum has one of the most skewed base-pair compositions of any eukaryote, with an AT content of 80–90%. As start and stop codons are AT-rich, the probability of finding upstream open reading frames (uORFs) in messenger RNAs (mRNAs) is high and parasite mRNAs have an average of 11 uORFs in their leader sequences. Similar to other eukaryotes, uORFs repress the translation of the downstream open reading frame (dORF) in P. falciparum, yet the parasite translation machinery is able to bypass these uORFs and reach the dORF to initiate translation. This can happen by leaky scanning and/or reinitiation.In this report, we assessed leaky scanning and reinitiation by studying the effect of uORFs on the translation of a dORF, in this case, the luciferase reporter gene, and showed that both mechanisms are employed in the asexual blood stages of P. falciparum. Furthermore, in addition to the codon usage of the uORF, translation of the dORF is governed by the Kozak sequence and length of the uORF, and inter-cistronic distance between the uORF and dORF. Based on these features whole-genome data was analysed to uncover classes of genes that might be regulated by uORFs. This study indicates that leaky scanning and reinitiation appear to be widespread in asexual stages of P. falciparum, which may require modifications of existing factors that are involved in translation initiation in addition to novel, parasite-specific proteins.
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8
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Sharaf A, Füssy Z, Tomčala A, Richtová J, Oborník M. Isolation of plastids and mitochondria from Chromera velia. PLANTA 2019; 250:1731-1741. [PMID: 31422509 DOI: 10.1007/s00425-019-03259-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/08/2019] [Indexed: 06/10/2023]
Abstract
We present an easy and effective procedure to purify plastids and mitochondria from Chromera velia. Our method enables downstream analyses of protein and metabolite content of the organelles. Chromerids are alveolate algae that are the closest known phototrophic relatives to apicomplexan parasites such as Plasmodium or Toxoplasma. While genomic and transcriptomic resources for chromerids are in place, tools and experimental conditions for proteomic studies have not been developed yet. Here we describe a rapid and efficient protocol for simultaneous isolation of plastids and mitochondria from the chromerid alga Chromera velia. This procedure involves enzymatic treatment and breakage of cells, followed by differential centrifugation. While plastids sediment in the first centrifugation step, mitochondria remain in the supernatant. Subsequently, plastids can be purified from the crude pellet by centrifugation on a discontinuous 60%/70% sucrose density gradient, while mitochondria can be obtained by centrifugation on a discontinuous 33%/80% Percoll density gradient. Isolated plastids are autofluorescent, and their multi-membrane structure was confirmed by transmission electron microscopy. Fluorescent optical microscopy was used to identify isolated mitochondria stained with MitoTrackerTM green, while their intactness and membrane potential were confirmed by staining with MitoTrackerTM orange CMTMRos. Total proteins were extracted from isolated organellar fractions, and the purity of isolated organelles was confirmed using immunoblotting. Antibodies against the beta subunit of the mitochondrial ATP synthase and the plastid protochlorophyllide oxidoreductase did not cross-react on immunoblots, suggesting that each organellar fraction is free of the residues of the other. The presented protocol represents an essential step for further proteomic, organellar, and cell biological studies of C. velia and can be employed, with minor optimizations, in other thick-walled unicellular algae.
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Affiliation(s)
- Abdoallah Sharaf
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.
- Genetic Department, Faculty of Agriculture, Ain Shams University, Cairo, 11241, Egypt.
| | - Zoltán Füssy
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Aleš Tomčala
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Jitka Richtová
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic
| | - Miroslav Oborník
- Institute of Parasitology, Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.
- Faculty of Science, University of South Bohemia, Branišovská 31, 37005, České Budějovice, Czech Republic.
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9
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Tiwari A, Kuldeep J, Siddiqi MI, Habib S. Plasmodium falciparumApn1 homolog is a mitochondrial base excision repair protein with restricted enzymatic functions. FEBS J 2019; 287:589-606. [DOI: 10.1111/febs.15032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 06/18/2019] [Accepted: 08/02/2019] [Indexed: 01/14/2023]
Affiliation(s)
- Anupama Tiwari
- Division of Molecular and Structural Biology CSIR‐Central Drug Research Institute Lucknow India
| | - Jitendra Kuldeep
- Division of Molecular and Structural Biology CSIR‐Central Drug Research Institute Lucknow India
| | - Mohammad Imran Siddiqi
- Division of Molecular and Structural Biology CSIR‐Central Drug Research Institute Lucknow India
| | - Saman Habib
- Division of Molecular and Structural Biology CSIR‐Central Drug Research Institute Lucknow India
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10
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Kennedy K, Crisafulli EM, Ralph SA. Delayed Death by Plastid Inhibition in Apicomplexan Parasites. Trends Parasitol 2019; 35:747-759. [PMID: 31427248 DOI: 10.1016/j.pt.2019.07.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 01/11/2023]
Abstract
The discovery of a plastid in apicomplexan parasites was hoped to be a watershed moment in the treatment of parasitic diseases as it revealed drug targets that are implicitly divergent from host molecular processes. Indeed, this organelle, known as the apicoplast, has since been a productive therapeutic target for pharmaceutical interventions against infections by Plasmodium, Toxoplasma, Babesia, and Theileria. However, some inhibitors of the apicoplast are restricted in their treatment utility because of their slow-kill kinetics, and this characteristic is called the delayed death effect. Here we review the recent genetic and pharmacological experiments that interrogate the causes of delayed death and explore the foundation of this phenomenon in Plasmodium and Toxoplasma parasites.
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Affiliation(s)
- Kit Kennedy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Emily M Crisafulli
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria, 3010, Australia.
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11
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Targeting the apicoplast in malaria. Biochem Soc Trans 2019; 47:973-983. [PMID: 31383817 DOI: 10.1042/bst20170563] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 05/22/2019] [Accepted: 06/10/2019] [Indexed: 12/25/2022]
Abstract
Malaria continues to be one of the leading causes of human mortality in the world, and the therapies available are insufficient for eradication. Severe malaria is caused by the apicomplexan parasite Plasmodium falciparum Apicomplexan parasites, including the Plasmodium spp., are descendants of photosynthetic algae, and therefore they possess an essential plastid organelle, named the apicoplast. Since humans and animals have no plastids, the apicoplast is an attractive target for drug development. Indeed, after its discovery, the apicoplast was found to host the target pathways of some known antimalarial drugs, which motivated efforts for further research into its biological functions and biogenesis. Initially, many apicoplast inhibitions were found to result in 'delayed death', whereby parasite killing is seen only at the end of one invasion-egress cycle. This slow action is not in line with the current standard for antimalarials, which seeded scepticism about the potential of compounds targeting apicoplast functions as good candidates for drug development. Intriguingly, recent evidence of apicoplast inhibitors causing rapid killing could put this organelle back in the spotlight. We provide an overview of drugs known to inhibit apicoplast pathways, alongside recent findings in apicoplast biology that may provide new avenues for drug development.
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12
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Kennedy K, Cobbold SA, Hanssen E, Birnbaum J, Spillman NJ, McHugh E, Brown H, Tilley L, Spielmann T, McConville MJ, Ralph SA. Delayed death in the malaria parasite Plasmodium falciparum is caused by disruption of prenylation-dependent intracellular trafficking. PLoS Biol 2019; 17:e3000376. [PMID: 31318858 PMCID: PMC6667170 DOI: 10.1371/journal.pbio.3000376] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2019] [Revised: 07/30/2019] [Accepted: 07/01/2019] [Indexed: 02/07/2023] Open
Abstract
Apicomplexan parasites possess a plastid organelle called the apicoplast. Inhibitors that selectively target apicoplast housekeeping functions, including DNA replication and protein translation, are lethal for the parasite, and several (doxycycline, clindamycin, and azithromycin) are in clinical use as antimalarials. A major limitation of such drugs is that treated parasites only arrest one intraerythrocytic development cycle (approximately 48 hours) after treatment commences, a phenotype known as the ‘delayed death’ effect. The molecular basis of delayed death is a long-standing mystery in parasitology, and establishing the mechanism would aid rational clinical implementation of apicoplast-targeted drugs. Parasites undergoing delayed death transmit defective apicoplasts to their daughter cells and cannot produce the sole, blood-stage essential metabolic product of the apicoplast: the isoprenoid precursor isopentenyl-pyrophosphate. How the isoprenoid precursor depletion kills the parasite remains unknown. We investigated the requirements for the range of isoprenoids in the human malaria parasite Plasmodium falciparum and characterised the molecular and morphological phenotype of parasites experiencing delayed death. Metabolomic profiling reveals disruption of digestive vacuole function in the absence of apicoplast derived isoprenoids. Three-dimensional electron microscopy reveals digestive vacuole fragmentation and the accumulation of cytostomal invaginations, characteristics common in digestive vacuole disruption. We show that digestive vacuole disruption results from a defect in the trafficking of vesicles to the digestive vacuole. The loss of prenylation of vesicular trafficking proteins abrogates their membrane attachment and function and prevents the parasite from feeding. Our data show that the proximate cause of delayed death is an interruption of protein prenylation and consequent cellular trafficking defects. After treatment with drugs that target apicoplast functions, malaria parasites are initially superficially healthy and go on to infect new erythrocytes. This cell biology study shows that the parasites subsequently die in their second cycle due to trafficking defects caused by depletion of prenyl groups.
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Affiliation(s)
- Kit Kennedy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Simon A. Cobbold
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Eric Hanssen
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
- Advanced Microscopy Facility, Bio21 Molecular Science and Biotechnology Institute, Victoria, Australia
| | - Jakob Birnbaum
- Molecular Biology and Immunology Section, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Natalie J. Spillman
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Emma McHugh
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Hannah Brown
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Tobias Spielmann
- Molecular Biology and Immunology Section, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Malcolm J. McConville
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
| | - Stuart A. Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria, Australia
- * E-mail:
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13
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Skinner-Adams TS, Fisher GM, Riches AG, Hutt OE, Jarvis KE, Wilson T, von Itzstein M, Chopra P, Antonova-Koch Y, Meister S, Winzeler EA, Clarke M, Fidock DA, Burrows JN, Ryan JH, Andrews KT. Cyclization-blocked proguanil as a strategy to improve the antimalarial activity of atovaquone. Commun Biol 2019; 2:166. [PMID: 31069275 PMCID: PMC6499835 DOI: 10.1038/s42003-019-0397-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 03/15/2019] [Indexed: 12/28/2022] Open
Abstract
Atovaquone-proguanil (Malarone®) is used for malaria prophylaxis and treatment. While the cytochrome bc1-inhibitor atovaquone has potent activity, proguanil's action is attributed to its cyclization-metabolite, cycloguanil. Evidence suggests that proguanil has limited intrinsic activity, associated with mitochondrial-function. Here we demonstrate that proguanil, and cyclization-blocked analogue tBuPG, have potent, but slow-acting, in vitro anti-plasmodial activity. Activity is folate-metabolism and isoprenoid biosynthesis-independent. In yeast dihydroorotate dehydrogenase-expressing parasites, proguanil and tBuPG slow-action remains, while bc1-inhibitor activity switches from comparatively fast to slow-acting. Like proguanil, tBuPG has activity against P. berghei liver-stage parasites. Both analogues act synergistically with bc1-inhibitors against blood-stages in vitro, however cycloguanil antagonizes activity. Together, these data suggest that proguanil is a potent slow-acting anti-plasmodial agent, that bc1 is essential to parasite survival independent of dihydroorotate dehydrogenase-activity, that Malarone® is a triple-drug combination that includes antagonistic partners and that a cyclization-blocked proguanil may be a superior combination partner for bc1-inhibitors in vivo.
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Affiliation(s)
- Tina S. Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111 Australia
| | - Gillian M. Fisher
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111 Australia
| | - Andrew G. Riches
- Commonwealth Scientific and Industrial Research Organization, Biomedical Manufacturing, Clayton, VIC 3168 Australia
| | - Oliver E. Hutt
- Commonwealth Scientific and Industrial Research Organization, Biomedical Manufacturing, Clayton, VIC 3168 Australia
| | - Karen E. Jarvis
- Commonwealth Scientific and Industrial Research Organization, Biomedical Manufacturing, Clayton, VIC 3168 Australia
| | - Tony Wilson
- Commonwealth Scientific and Industrial Research Organization, Biomedical Manufacturing, Clayton, VIC 3168 Australia
| | - Mark von Itzstein
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, QLD 4222 Australia
| | - Pradeep Chopra
- Institute for Glycomics, Griffith University Gold Coast Campus, Gold Coast, QLD 4222 Australia
| | - Yevgeniya Antonova-Koch
- School of Medicine, University of California, San Diego, La Jolla, CA 92093 USA
- Present Address: California Institute for Biomedical Research (Calibr), La Jolla, CA 92037 USA
| | - Stephan Meister
- School of Medicine, University of California, San Diego, La Jolla, CA 92093 USA
- Present Address: Beckman Coulter Life Sciences in Indianapolis, Indianapolis, IN 46268 USA
| | | | - Mary Clarke
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111 Australia
| | - David A. Fidock
- Department of Microbiology and Immunology, and Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY 10032 USA
| | - Jeremy N. Burrows
- Medicines for Malaria Venture (MMV), Route de Pré Bois 20, Geneva, 1215 Switzerland
| | - John H. Ryan
- Commonwealth Scientific and Industrial Research Organization, Biomedical Manufacturing, Clayton, VIC 3168 Australia
| | - Katherine T. Andrews
- Griffith Institute for Drug Discovery, Griffith University, Nathan, QLD 4111 Australia
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14
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Identification of Antimalarial Compounds That Require CLAG3 for Their Uptake by Plasmodium falciparum-Infected Erythrocytes. Antimicrob Agents Chemother 2019; 63:AAC.00052-19. [PMID: 30782998 DOI: 10.1128/aac.00052-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 01/15/2023] Open
Abstract
During the intraerythrocytic asexual cycle malaria parasites acquire nutrients and other solutes through a broad selectivity channel localized at the membrane of the infected erythrocyte termed the plasmodial surface anion channel (PSAC). The protein product of the Plasmodium falciparum clonally variant clag3.1 and clag3.2 genes determines PSAC activity. Switches in the expression of clag3 genes, which are regulated by epigenetic mechanisms, are associated with changes in PSAC-dependent permeability that can result in resistance to compounds toxic for the parasite, such as blasticidin S. Here, we investigated whether other antimalarial drugs require CLAG3 to reach their intracellular target and consequently are prone to parasite resistance by epigenetic mechanisms. We found that the bis-thiazolium salts T3 (also known as albitiazolium) and T16 require the product of clag3 genes to enter infected erythrocytes. P. falciparum populations can develop resistance to these compounds via the selection of parasites with dramatically reduced expression of both genes. However, other compounds previously demonstrated or predicted to enter infected erythrocytes through transport pathways absent from noninfected erythrocytes, such as fosmidomycin, doxycycline, azithromycin, lumefantrine, or pentamidine, do not require expression of clag3 genes for their antimalarial activity. This suggests that they use alternative CLAG3-independent routes to access parasites. Our results demonstrate that P. falciparum can develop resistance to diverse antimalarial compounds by epigenetic changes in the expression of clag3 genes. This is of concern for drug development efforts because drug resistance by epigenetic mechanisms can arise quickly, even during the course of a single infection.
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15
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Tang Y, Meister TR, Walczak M, Pulkoski-Gross MJ, Hari SB, Sauer RT, Amberg-Johnson K, Yeh E. A mutagenesis screen for essential plastid biogenesis genes in human malaria parasites. PLoS Biol 2019; 17:e3000136. [PMID: 30726238 PMCID: PMC6380595 DOI: 10.1371/journal.pbio.3000136] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 02/19/2019] [Indexed: 02/06/2023] Open
Abstract
Endosymbiosis has driven major molecular and cellular innovations. Plasmodium spp. parasites that cause malaria contain an essential, non-photosynthetic plastid-the apicoplast-which originated from a secondary (eukaryote-eukaryote) endosymbiosis. To discover organellar pathways with evolutionary and biomedical significance, we performed a mutagenesis screen for essential genes required for apicoplast biogenesis in Plasmodium falciparum. Apicoplast(-) mutants were isolated using a chemical rescue that permits conditional disruption of the apicoplast and a new fluorescent reporter for organelle loss. Five candidate genes were validated (out of 12 identified), including a triosephosphate isomerase (TIM)-barrel protein that likely derived from a core metabolic enzyme but evolved a new activity. Our results demonstrate, to our knowledge, the first forward genetic screen to assign essential cellular functions to unannotated P. falciparum genes. A putative TIM-barrel enzyme and other newly identified apicoplast biogenesis proteins open opportunities to discover new mechanisms of organelle biogenesis, molecular evolution underlying eukaryotic diversity, and drug targets against multiple parasitic diseases.
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Affiliation(s)
- Yong Tang
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Thomas R. Meister
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Marta Walczak
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Michael J. Pulkoski-Gross
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
| | - Sanjay B. Hari
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Robert T. Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Katherine Amberg-Johnson
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
| | - Ellen Yeh
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, United States of America
- Department of Pathology, Stanford University School of Medicine, Stanford, California, United States of America
- Chan Zuckerberg Biohub, San Francisco, California, United States of America
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16
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Mallo N, Fellows J, Johnson C, Sheiner L. Protein Import into the Endosymbiotic Organelles of Apicomplexan Parasites. Genes (Basel) 2018; 9:E412. [PMID: 30110980 PMCID: PMC6115763 DOI: 10.3390/genes9080412] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 07/31/2018] [Accepted: 08/07/2018] [Indexed: 01/26/2023] Open
Abstract
: The organelles of endosymbiotic origin, plastids, and mitochondria, evolved through the serial acquisition of endosymbionts by a host cell. These events were accompanied by gene transfer from the symbionts to the host, resulting in most of the organellar proteins being encoded in the cell nuclear genome and trafficked into the organelle via a series of translocation complexes. Much of what is known about organelle protein translocation mechanisms is based on studies performed in common model organisms; e.g., yeast and humans or Arabidopsis. However, studies performed in divergent organisms are gradually accumulating. These studies provide insights into universally conserved traits, while discovering traits that are specific to organisms or clades. Apicomplexan parasites feature two organelles of endosymbiotic origin: a secondary plastid named the apicoplast and a mitochondrion. In the context of the diseases caused by apicomplexan parasites, the essential roles and divergent features of both organelles make them prime targets for drug discovery. This potential and the amenability of the apicomplexan Toxoplasma gondii to genetic manipulation motivated research about the mechanisms controlling both organelles' biogenesis. Here we provide an overview of what is known about apicomplexan organelle protein import. We focus on work done mainly in T. gondii and provide a comparison to model organisms.
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Affiliation(s)
- Natalia Mallo
- Wellcome Centre for Molecular Parasitology, University of Glasgow, 120 University Place Glasgow, Glasgow G12 8QQ, UK.
| | - Justin Fellows
- Genetics and Biochemistry Branch, National Institute for Diabetes and Digestive and Kidney Disease, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Carla Johnson
- Wellcome Centre for Molecular Parasitology, University of Glasgow, 120 University Place Glasgow, Glasgow G12 8QQ, UK.
| | - Lilach Sheiner
- Wellcome Centre for Molecular Parasitology, University of Glasgow, 120 University Place Glasgow, Glasgow G12 8QQ, UK.
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17
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Kattenberg JH, Erhart A, Truong MH, Rovira-Vallbona E, Vu KAD, Nguyen THN, Nguyen VH, Nguyen VV, Bannister-Tyrrell M, Theisen M, Bennet A, Lover AA, Tran TD, Nguyen XX, Rosanas-Urgell A. Characterization of Plasmodium falciparum and Plasmodium vivax recent exposure in an area of significantly decreased transmission intensity in Central Vietnam. Malar J 2018; 17:180. [PMID: 29703200 PMCID: PMC5923009 DOI: 10.1186/s12936-018-2326-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 04/18/2018] [Indexed: 11/30/2022] Open
Abstract
Background In Vietnam, malaria transmission has been reduced to very low levels over the past 20 years, and as a consequence, the country aims to eliminate malaria by 2030. This study aimed to characterize the dynamics and extent of the parasite reservoir in Central Vietnam, in order to further target elimination strategies and surveillance. Methods A 1-year prospective cohort study (n = 429) was performed in three rural communities in Quang Nam province. Six malaria screenings were conducted between November 2014 and November 2015, including systematic clinical examination and blood sampling for malaria parasite identification, as well as molecular and serological analysis of the study population. Malaria infections were detected by light microscopy (LM) and quantitative real time PCR (qPCR), while exposure to Plasmodium falciparum and Plasmodium vivax was measured in the first and last survey by ELISA for PfAMA1, PfGLURP R2, PvAMA1, and PvMSP1-19. Classification and regression trees were used to define seropositivity and recent exposure. Results Four malaria infections (2 P. falciparum, 2 P. vivax) were detected in the same village by qPCR and/or LM. No fever cases were attributable to malaria. At the same time, the commune health centre (serving a larger area) reported few cases of confirmed malaria cases. Nevertheless, serological data proved that 13.5% of the surveyed population was exposed to P. falciparum and/or P. vivax parasites during the study period, of which 32.6% were seronegative at the start of the study, indicating ongoing transmission in the area. Risk factor analysis for seroprevalence and exposure to P. falciparum and/or P. vivax identified structural or economic risk factors and activity/behaviour-related factors, as well as spatial heterogeneity at the village level. Conclusions Previous studies in Central Vietnam demonstrated high occurrence of asymptomatic and sub-microscopic infections. However, in this study very few asymptomatic infections were detected despite serological evidence of continued transmission. Nonetheless, the factors associated with spatial heterogeneity in transmission could be evaluated using serological classification of recent exposure, which supports the usefulness of serological methods to monitor malaria transmission. Electronic supplementary material The online version of this article (10.1186/s12936-018-2326-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Annette Erhart
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium.,MRC Unit, Fajara, The Gambia.,Global Health Institute, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Minh Hieu Truong
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | | | - Khac Anh Dung Vu
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Thi Hong Ngoc Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Van Hong Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Van Van Nguyen
- Provincial Malaria Station Quang Nam/Center for Malaria and Goitre Control, Quang Nam Province, Tam Ky, Vietnam
| | | | | | - Adam Bennet
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Andrew A Lover
- Malaria Elimination Initiative, Institute for Global Health Sciences, University of California, San Francisco, USA
| | - Thanh Duong Tran
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Xuan Xa Nguyen
- National Institute of Malariology, Parasitology and Entomology, Vietnam, Luong The Vinh Street 245-Trung Van, BC 10.200 Tu Liem, Hanoi, Vietnam
| | - Anna Rosanas-Urgell
- Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium.
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18
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Ke H, Dass S, Morrisey JM, Mather MW, Vaidya AB. The mitochondrial ribosomal protein L13 is critical for the structural and functional integrity of the mitochondrion in Plasmodium falciparum. J Biol Chem 2018; 293:8128-8137. [PMID: 29626096 DOI: 10.1074/jbc.ra118.002552] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/02/2018] [Indexed: 12/22/2022] Open
Abstract
The phylum Apicomplexa contains a group of protozoa causing diseases in humans and livestock. Plasmodium spp., the causative agent of malaria, contains a mitochondrion that is very divergent from that of their hosts. The malarial mitochondrion is a clinically validated target for the antimalarial drug atovaquone, which specifically blocks the electron transfer activity of the bc1 complex of the mitochondrial electron transport chain (mtETC). Most mtETC proteins are nuclear-encoded and imported from the cytosol, but three key protein subunits are encoded in the Plasmodium mitochondrial genome: cyt b, COXI, and COXIII. They are translated inside the mitochondrion by mitochondrial ribosomes (mitoribosomes). Here, we characterize the function of one large mitoribosomal protein in Plasmodium falciparum, PfmRPL13. We found that PfmRPL13 localizes to the parasite mitochondrion and is refractory to genetic knockout. Ablation of PfmRPL13 using a conditional knockdown system (TetR-DOZI-aptamer) caused a series of adverse events in the parasite, including mtETC deficiency, loss of mitochondrial membrane potential (Δψm), and death. The PfmRPL13 knockdown parasite also became hypersensitive to proguanil, a drug proposed to target an alternative process for maintaining Δψm Surprisingly, transmission EM revealed that PfmRPL13 disruption also resulted in an unusually elongated and branched mitochondrion. The growth arrest of the knockdown parasite could be rescued with a second copy of PfmRPL13, but not by supplementation with decylubiquinone or addition of a yeast dihydroorotate dehydrogenase gene. In summary, we provide first and direct evidence that mitoribosomes are essential for malaria parasites to maintain the structural and functional integrity of the mitochondrion.
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Affiliation(s)
- Hangjun Ke
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129.
| | - Swati Dass
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Joanne M Morrisey
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Michael W Mather
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
| | - Akhil B Vaidya
- Center for Molecular Parasitology, Department of Microbiology and Immunology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129
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19
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Manickam Y, Chaturvedi R, Babbar P, Malhotra N, Jain V, Sharma A. Drug targeting of one or more aminoacyl-tRNA synthetase in the malaria parasite Plasmodium falciparum. Drug Discov Today 2018; 23:1233-1240. [PMID: 29408369 DOI: 10.1016/j.drudis.2018.01.050] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/02/2018] [Accepted: 01/29/2018] [Indexed: 11/28/2022]
Abstract
Malaria remains a major infectious disease and, despite incidence reduction, it threatens resurgence in drug-resistant forms. Antimalarial drugs remain the mainstay of therapeutic options and hence there is a constant need to identify and validate new druggable targets. Plasmodium falciparum aminoacyl-tRNA synthetases (Pf-aaRSs) drive protein translation and are potent targets for development of next-generation antimalarials. Here, we detail advances made in structural-biology-based investigations in Pf-aaRSs and discuss their distribution of druggable pockets. This review establishes a platform for systematic experimental dissection of malarial parasite aaRSs as a new focus for sustained drug development efforts against malaria.
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Affiliation(s)
- Yogavel Manickam
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Rini Chaturvedi
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Palak Babbar
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Nipun Malhotra
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India
| | - Vitul Jain
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India; Present address: Division of Structural Biology, Wellcome Trust Centre for Human Genetics, The Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK
| | - Amit Sharma
- Molecular Medicine Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi 110067, India.
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20
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Mundra S, Thakur V, Bello AM, Rathore S, Asad M, Wei L, Yang J, Chakka SK, Mahesh R, Malhotra P, Mohmmed A, Kotra LP. A novel class of Plasmodial ClpP protease inhibitors as potential antimalarial agents. Bioorg Med Chem 2017; 25:5662-5677. [DOI: 10.1016/j.bmc.2017.08.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 08/17/2017] [Accepted: 08/24/2017] [Indexed: 01/25/2023]
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21
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Blasco B, Leroy D, Fidock DA. Antimalarial drug resistance: linking Plasmodium falciparum parasite biology to the clinic. Nat Med 2017; 23:917-928. [PMID: 28777791 DOI: 10.1038/nm.4381] [Citation(s) in RCA: 325] [Impact Index Per Article: 46.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 06/30/2017] [Indexed: 02/08/2023]
Abstract
The global adoption of artemisinin-based combination therapies (ACTs) in the early 2000s heralded a new era in effectively treating drug-resistant Plasmodium falciparum malaria. However, several Southeast Asian countries have now reported the emergence of parasites that have decreased susceptibility to artemisinin (ART) derivatives and ACT partner drugs, resulting in increasing rates of treatment failures. Here we review recent advances in understanding how antimalarials act and how resistance develops, and discuss new strategies for effectively combatting resistance, optimizing treatment and advancing the global campaign to eliminate malaria.
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Affiliation(s)
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, New York, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, New York, USA
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22
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The Candidate Antimalarial Drug MMV665909 Causes Oxygen-Dependent mRNA Mistranslation and Synergizes with Quinoline-Derived Antimalarials. Antimicrob Agents Chemother 2017; 61:AAC.00459-17. [PMID: 28652237 PMCID: PMC5571370 DOI: 10.1128/aac.00459-17] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/17/2017] [Indexed: 12/18/2022] Open
Abstract
To cope with growing resistance to current antimalarials, new drugs with novel modes of action are urgently needed. Molecules targeting protein synthesis appear to be promising candidates. We identified a compound (MMV665909) from the Medicines for Malaria Venture (MMV) Malaria Box of candidate antimalarials that could produce synergistic growth inhibition with the aminoglycoside antibiotic paromomycin, suggesting a possible action of the compound in mRNA mistranslation. This mechanism of action was substantiated with a Saccharomyces cerevisiae model using available reporters of mistranslation and other genetic tools. Mistranslation induced by MMV665909 was oxygen dependent, suggesting a role for reactive oxygen species (ROS). Overexpression of Rli1 (a ROS-sensitive, conserved FeS protein essential in mRNA translation) rescued inhibition by MMV665909, consistent with the drug's action on translation fidelity being mediated through Rli1. The MMV drug also synergized with major quinoline-derived antimalarials which can perturb amino acid availability or promote ROS stress: chloroquine, amodiaquine, and primaquine. The data collectively suggest translation fidelity as a novel target of antimalarial action and support MMV665909 as a promising drug candidate.
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23
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Bharti DR, Lynn AM. QSAR based predictive modeling for anti-malarial molecules. Bioinformation 2017; 13:154-159. [PMID: 28690382 PMCID: PMC5498782 DOI: 10.6026/97320630013154] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 04/21/2017] [Indexed: 01/16/2023] Open
Abstract
Malaria is a predominant infectious disease, with a global footprint, but especially severe in developing countries in the African subcontinent. In recent years, drug-resistant malaria has become an alarming factor, and hence the requirement of new and improved drugs is more crucial than ever before. One of the promising locations for antimalarial drug target is the apicoplast, as this organelle does not occur in humans. The apicoplast is associated with many unique and essential pathways in many Apicomplexan pathogens, including Plasmodium. The use of machine learning methods is now commonly available through open source programs. In the present work, we describe a standard protocol to develop molecular descriptor based predictive models (QSAR models), which can be further utilized for the screening of large chemical libraries. This protocol is used to build models using training data sourced from apicoplast specific bioassays. Multiple model building methods are used including Generalized Linear Models (GLM), Random Forest (RF), C5.0 implementation of a decision tree, Support Vector Machines (SVM), K-Nearest Neighbour and Naive Bayes. Methods to evaluate the accuracy of the model building method are included in the protocol. For the given dataset, the C5.0, SVM and RF perform better than other methods, with comparable accuracy over the test data.
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Affiliation(s)
- Deepak R. Bharti
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi-67
| | - Andrew M. Lynn
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi-67
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