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Amanzougaghene N, Tajeri S, Franetich JF, Ashraf K, Soulard V, Bigeard P, Guindo CO, Bouillier C, Lemaitre J, Relouzat F, Legrand R, Kocken CHM, Zeeman AM, Roobsoong W, Sattabongkot J, Yang Z, Snounou G, Mazier D. Azithromycin disrupts apicoplast biogenesis in replicating and dormant liver stages of the relapsing malaria parasites Plasmodium vivax and Plasmodium cynomolgi. Int J Antimicrob Agents 2024; 63:107112. [PMID: 38367843 DOI: 10.1016/j.ijantimicag.2024.107112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 01/31/2024] [Accepted: 02/08/2024] [Indexed: 02/19/2024]
Abstract
The control and elimination of malaria caused by Plasmodium vivax is hampered by the threat of relapsed infection resulting from the activation of dormant hepatic hypnozoites. Currently, only the 8-aminoquinolines, primaquine and tafenoquine, have been approved for the elimination of hypnozoites, although their use is hampered by potential toxicity. Therefore, an alternative radical curative drug that safely eliminates hypnozoites is a pressing need. This study assessed the potential hypnozoiticidal activity of the antibiotic azithromycin, which is thought to exert antimalarial activity by inhibiting prokaryote-like ribosomal translation within the apicoplast, an indispensable organelle. The results show that azithromycin inhibited apicoplast development during liver-stage schizogony in P. vivax and Plasmodium cynomolgi, leading to impaired parasite maturation. More importantly, this study found that azithromycin is likely to impair the hypnozoite's apicoplast, resulting in the loss of this organelle. Subsequently, using a recently developed long-term hepatocyte culture system, this study found that this loss likely induces a delay in the hypnozoite activation rate, and that those parasites that do proceed to schizogony display liver-stage arrest prior to differentiating into hepatic merozoites, thus potentially preventing relapse. Overall, this work provides evidence for the potential use of azithromycin for the radical cure of relapsing malaria, and identifies apicoplast functions as potential drug targets in quiescent hypnozoites.
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Affiliation(s)
- Nadia Amanzougaghene
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France; Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France
| | - Shahin Tajeri
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Jean-François Franetich
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Kutub Ashraf
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Valérie Soulard
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Pierre Bigeard
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Cheick Oumar Guindo
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France
| | - Camille Bouillier
- Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France
| | - Julien Lemaitre
- Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France
| | - Francis Relouzat
- Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France
| | - Roger Legrand
- Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France
| | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Anne-Marie Zeeman
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, The Netherlands
| | - Wanlapa Roobsoong
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine Mahidol University, Bangkok, Thailand
| | - Jetsumon Sattabongkot
- Mahidol Vivax Research Unit, Faculty of Tropical Medicine Mahidol University, Bangkok, Thailand
| | - Zhaoqing Yang
- Department of Pathogen Biology and Immunology, Kunming Medical University, Chenggong New Town, Kunming, Yunnan Province,China
| | - Georges Snounou
- Université Paris-Saclay, Inserm, CEA, Immunologie des maladies virales, auto-immunes, hématologiques et bactériennes (IMVA-HB/IDMIT/UMR1184), Fontenay-aux-Roses and Kremlin-Bicêtre, France.
| | - Dominique Mazier
- Sorbonne Université, INSERM, CNRS, Centre d'Immunologie et des Maladies Infectieuses, CIMI-Paris, Paris, France.
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Holbrook NR, Klontz EH, Adams GC, Schnittman SR, Issa NC, Bond SA, Branda JA, Lemieux JE. Babesia microti Variant With Multiple Resistance Mutations Detected in an Immunocompromised Patient Receiving Atovaquone Prophylaxis. Open Forum Infect Dis 2023; 10:ofad097. [PMID: 36968958 PMCID: PMC10034591 DOI: 10.1093/ofid/ofad097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 02/21/2023] [Indexed: 02/25/2023] Open
Abstract
We report Babesia microti genomic sequences with multiple mutations in the atovaquone-target region of cytochrome b, including a newly identified Y272S mutation, plus 1 mutation of undetermined significance in the azithromycin-associated ribosomal protein L4. The parasite was sequenced from an immunocompromised patient on prophylactic atovaquone for Pneumocystis pneumonia before diagnosis of babesiosis.
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Affiliation(s)
- Nolan R Holbrook
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
- Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Erik H Klontz
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Gordon C Adams
- Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Samuel R Schnittman
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Nicolas C Issa
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - Sheila A Bond
- Division of Infectious Diseases, Brigham and Women’s Hospital, Boston, Massachusetts, USA
| | - John A Branda
- Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Jacob E Lemieux
- Infectious Diseases Division, Massachusetts General Hospital, Boston, Massachusetts, USA
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Sié A, Bountogo M, Zakane A, Compaoré G, Ouedraogo T, Lebas E, Nyatigo F, Hu H, Brogdon J, Arnold BF, Lietman TM, Oldenburg CE. Effect of Neonatal Azithromycin on All-Cause and Cause-Specific Infant Mortality: A Randomized Controlled Trial. Am J Trop Med Hyg 2022; 107:1331-1336. [PMID: 36343592 PMCID: PMC9768279 DOI: 10.4269/ajtmh.22-0245] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 08/20/2022] [Indexed: 11/09/2022] Open
Abstract
Mass azithromycin distribution reduces all-cause childhood mortality in some high-mortality settings in sub-Saharan Africa. Although the greatest benefits have been shown in children 1 to 5 months old living in areas with high mortality rates, no evidence of a benefit was found of neonatal azithromycin in a low-mortality setting on mortality at 6 months. We conducted a 1:1 randomized, placebo-controlled trial evaluating the effect of a single oral 20-mg/kg dose of azithromycin or matching placebo administered during the neonatal period on all-cause and cause-specific infant mortality at 12 months of age in five regions of Burkina Faso. Neonates were eligible if they were between the ages of 8 and 27 days and weighed at least 2,500 g at enrollment. Cause of death was determined via the WHO 2016 verbal autopsy tool. We compared all-cause and cause-specific mortality using binomial regression. Of 21,832 infants enrolled in the study, 116 died by 12 months of age. There was no significant difference in all-cause mortality between the azithromycin and placebo groups (azithromycin: 52 deaths, 0.5%; placebo, 64 deaths, 0.7%; hazard ratio, 0.81; 95% CI, 0.56-1.17; P = 0.30). There was no evidence of a difference in the distribution of causes of death (P = 0.40) and no significant difference in any specific cause of death between groups. Mortality rates were low at 12 months of age, and there was no evidence of an effect of neonatal azithromycin on all-cause or cause-specific mortality.
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Affiliation(s)
- Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | | | | | | | | | - Elodie Lebas
- Francis I Proctor Foundation, University of California, San Francisco, California
| | - Fanice Nyatigo
- Francis I Proctor Foundation, University of California, San Francisco, California
| | - Huiyu Hu
- Francis I Proctor Foundation, University of California, San Francisco, California
| | - Jessica Brogdon
- Francis I Proctor Foundation, University of California, San Francisco, California
| | - Benjamin F. Arnold
- Francis I Proctor Foundation, University of California, San Francisco, California
- Department of Ophthalmology, University of California, San Francisco, California
| | - Thomas M. Lietman
- Francis I Proctor Foundation, University of California, San Francisco, California
- Department of Ophthalmology, University of California, San Francisco, California
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California
| | - Catherine E. Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, California
- Department of Ophthalmology, University of California, San Francisco, California
- Department of Epidemiology & Biostatistics, University of California, San Francisco, California
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Burns AL, Sleebs BE, Gancheva M, McLean KT, Siddiqui G, Venter H, Beeson JG, O’Handley R, Creek DJ, Ma S, Frölich S, Goodman CD, McFadden GI, Wilson DW. Targeting malaria parasites with novel derivatives of azithromycin. Front Cell Infect Microbiol 2022; 12:1063407. [PMID: 36530422 PMCID: PMC9748569 DOI: 10.3389/fcimb.2022.1063407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 11/09/2022] [Indexed: 12/02/2022] Open
Abstract
Introduction The spread of artemisinin resistant Plasmodium falciparum parasites is of global concern and highlights the need to identify new antimalarials for future treatments. Azithromycin, a macrolide antibiotic used clinically against malaria, kills parasites via two mechanisms: 'delayed death' by inhibiting the bacterium-like ribosomes of the apicoplast, and 'quick-killing' that kills rapidly across the entire blood stage development. Methods Here, 22 azithromycin analogues were explored for delayed death and quick-killing activities against P. falciparum (the most virulent human malaria) and P. knowlesi (a monkey parasite that frequently infects humans). Results Seventeen analogues showed improved quick-killing against both Plasmodium species, with up to 38 to 20-fold higher potency over azithromycin after less than 48 or 28 hours of treatment for P. falciparum and P. knowlesi, respectively. Quick-killing analogues maintained activity throughout the blood stage lifecycle, including ring stages of P. falciparum parasites (<12 hrs treatment) and were >5-fold more selective against P. falciparum than human cells. Isopentenyl pyrophosphate supplemented parasites that lacked an apicoplast were equally sensitive to quick-killing analogues, confirming that the quick killing activity of these drugs was not directed at the apicoplast. Further, activity against the related apicoplast containing parasite Toxoplasma gondii and the gram-positive bacterium Streptococcus pneumoniae did not show improvement over azithromycin, highlighting the specific improvement in antimalarial quick-killing activity. Metabolomic profiling of parasites subjected to the most potent compound showed a build-up of non-haemoglobin derived peptides that was similar to chloroquine, while also exhibiting accumulation of haemoglobin-derived peptides that was absent for chloroquine treatment. Discussion The azithromycin analogues characterised in this study expand the structural diversity over previously reported quick-killing compounds and provide new starting points to develop azithromycin analogues with quick-killing antimalarial activity.
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Affiliation(s)
- Amy L. Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,School of Science and Technology, the University of New England, Armidale, NSW, Australia
| | - Brad E. Sleebs
- ACRF Chemical Biology Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia,Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Maria Gancheva
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Kimberley T. McLean
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | - Ghizal Siddiqui
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Henrietta Venter
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - James G. Beeson
- Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Department of Medicine, University of Melbourne, Parkville, VIC, Australia,Central Clinical School, Monash University, Melbourne, Vic, Australia,Department of Microbiology, Monash University, Melbourne, Vic, Australia
| | - Ryan O’Handley
- School of Animal and Veterinary Science, University of Adelaide, Adelaide, SA, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia
| | - Darren J. Creek
- Drug Delivery Disposition and Dynamics, Monash University, Parkville, VIC, Australia
| | - Shutao Ma
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology, Ministry of Education, School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Sonja Frölich
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia
| | | | | | - Danny W. Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, the University of Adelaide, Adelaide, SA, Australia,Healthy Mothers, Healthy Babies Program, Burnet Institute, Melbourne, VIC, Australia,Australian Centre for Antimicrobial Resistance Ecology, The University of Adelaide, Adelaide, SA, Australia,*Correspondence: Danny W. Wilson,
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Effect of biannual azithromycin distribution on antibody responses to malaria, bacterial, and protozoan pathogens in Niger. Nat Commun 2022; 13:976. [PMID: 35190534 PMCID: PMC8861117 DOI: 10.1038/s41467-022-28565-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 02/02/2022] [Indexed: 11/30/2022] Open
Abstract
The MORDOR trial in Niger, Malawi, and Tanzania found that biannual mass distribution of azithromycin to children younger than 5 years led to a 13.5% reduction in all-cause mortality (NCT02048007). To help elucidate the mechanism for mortality reduction, we report IgG responses to 11 malaria, bacterial, and protozoan pathogens using a multiplex bead assay in pre-specified substudy of 30 communities in the rural Niger placebo-controlled trial over a three-year period (n = 5642 blood specimens, n = 3814 children ages 1–59 months). Mass azithromycin reduces Campylobacter spp. force of infection by 29% (hazard ratio = 0.71, 95% CI: 0.56, 0.89; P = 0.004) but serological measures show no significant differences between groups for other pathogens against a backdrop of high transmission. Results align with a recent microbiome study in the communities. Given significant sequelae of Campylobacter infection among preschool aged children, our results support an important mechanism through which biannual mass distribution of azithromycin likely reduces mortality in Niger. In a randomized placebo-controlled trial in rural Niger, biannual azithromycin distribution to children 1-59 months reduced all-cause mortality. Based on serology, Arzika et al. here report a reduction of Campylobacter infection, supporting one mechanism for the intervention’s impact on mortality.
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6
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Endo T, Takemae H, Sharma I, Furuya T. Multipurpose Drugs Active Against Both Plasmodium spp. and Microorganisms: Potential Application for New Drug Development. Front Cell Infect Microbiol 2021; 11:797509. [PMID: 35004357 PMCID: PMC8740689 DOI: 10.3389/fcimb.2021.797509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/01/2021] [Indexed: 12/29/2022] Open
Abstract
Malaria, a disease caused by the protozoan parasites Plasmodium spp., is still causing serious problems in endemic regions in the world. Although the WHO recommends artemisinin combination therapies for the treatment of malaria patients, the emergence of artemisinin-resistant parasites has become a serious issue and underscores the need for the development of new antimalarial drugs. On the other hand, new and re-emergences of infectious diseases, such as the influenza pandemic, Ebola virus disease, and COVID-19, are urging the world to develop effective chemotherapeutic agents against the causative viruses, which are not achieved to the desired level yet. In this review article, we describe existing drugs which are active against both Plasmodium spp. and microorganisms including viruses, bacteria, and fungi. We also focus on the current knowledge about the mechanism of actions of these drugs. Our major aims of this article are to describe examples of drugs that kill both Plasmodium parasites and other microbes and to provide valuable information to help find new ideas for developing novel drugs, rather than merely augmenting already existing drug repurposing efforts.
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Affiliation(s)
- Takuro Endo
- Laboratory of Veterinary Infectious Diseases, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Hitoshi Takemae
- Center for Infectious Disease Epidemiology and Prevention Research, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Indu Sharma
- Department of Biological Sciences, Hampton University, Hampton, VA, United States
| | - Tetsuya Furuya
- Laboratory of Veterinary Infectious Diseases, Cooperative Department of Veterinary Medicine, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Tokyo, Japan
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Bhadra PK, Magwaza RN, Nirmalan N, Freeman S, Barber J, Arsic B. Selected Derivatives of Erythromycin B- In Silico and Anti-Malarial Studies. MATERIALS 2021; 14:ma14226980. [PMID: 34832380 PMCID: PMC8618316 DOI: 10.3390/ma14226980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/10/2021] [Accepted: 11/12/2021] [Indexed: 12/01/2022]
Abstract
Erythromycin A is an established anti-bacterial agent against Gram-positive bacteria, but it is unstable to acid. This led to an evaluation of erythromycin B and its derivatives because these have improved acid stability. These compounds were investigated for their anti-malarial activities, by their in silico molecular docking into segments of the exit tunnel of the apicoplast ribosome from Plasmodium falciparum. This is believed to be the target of the erythromycin A derivative, azithromycin, which has mild anti-malarial activity. The erythromycin B derivatives were evaluated on the multi-drug (chloroquine, pyrimethamine, and sulfadoxine)-resistant strain K1 of P. falciparum for asexual growth inhibition on asynchronous culture. The erythromycin B derivatives were identified as active in vitro inhibitors of asexual growth of P. falciparum with low micro-molar IC50 values after a 72 h cycle. 5-Desosaminyl erythronolide B ethyl succinate showed low IC50 of 68.6 µM, d-erythromycin B 86.8 µM, and erythromycin B 9-oxime 146.0 µM on the multi-drug-resistant K1 of P. falciparum. Based on the molecular docking, it seems that a small number of favourable interactions or the presence of unfavourable interactions of investigated derivatives of erythromycin B with in silico constructed segment from the exit tunnel from the apicoplast of P. falciparum is the reason for their weak in vitro anti-malarial activities.
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Affiliation(s)
- Pranab K. Bhadra
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK; (P.K.B.); (R.N.M.); (S.F.); (J.B.)
| | - Rachael N. Magwaza
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK; (P.K.B.); (R.N.M.); (S.F.); (J.B.)
| | - Niroshini Nirmalan
- School of Science, Engineering & Environment, University of Salford, Manchester M5 4WT, UK;
| | - Sally Freeman
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK; (P.K.B.); (R.N.M.); (S.F.); (J.B.)
| | - Jill Barber
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK; (P.K.B.); (R.N.M.); (S.F.); (J.B.)
| | - Biljana Arsic
- Division of Pharmacy and Optometry, School of Health Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK; (P.K.B.); (R.N.M.); (S.F.); (J.B.)
- Department of Chemistry, Faculty of Sciences and Mathematics, University of Nis, Visegradska 33, 18000 Nis, Serbia
- Correspondence: or
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8
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Renard I, Ben Mamoun C. Treatment of Human Babesiosis: Then and Now. Pathogens 2021; 10:pathogens10091120. [PMID: 34578153 PMCID: PMC8469882 DOI: 10.3390/pathogens10091120] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/23/2021] [Accepted: 08/27/2021] [Indexed: 12/26/2022] Open
Abstract
Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus Babesia. With its increasing incidence worldwide and the risk of human-to-human transmission through blood transfusion, babesiosis is becoming a rising public health concern. The current arsenal for the treatment of human babesiosis is limited and consists of combinations of atovaquone and azithromycin or clindamycin and quinine. These combination therapies were not designed based on biological criteria unique to Babesia parasites, but were rather repurposed based on their well-established efficacy against other apicomplexan parasites. However, these compounds are associated with mild or severe adverse events and a rapid emergence of drug resistance, thus highlighting the need for new therapeutic strategies that are specifically tailored to Babesia parasites. Herein, we review ongoing babesiosis therapeutic and management strategies and their limitations, and further review current efforts to develop new, effective, and safer therapies for the treatment of this disease.
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9
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Coulibaly B, Sié A, Dah C, Bountogo M, Ouattara M, Compaoré A, Nikiema M, Tiansi JN, Sibiri ND, Brogdon JM, Lebas E, Doan T, Porco TC, Lietman TM, Oldenburg CE. Effect of a single dose of oral azithromycin on malaria parasitaemia in children: a randomized controlled trial. Malar J 2021; 20:360. [PMID: 34465327 PMCID: PMC8407066 DOI: 10.1186/s12936-021-03895-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/25/2021] [Indexed: 11/10/2022] Open
Abstract
Background Azithromycin has recently been shown to reduce all-cause childhood mortality in sub-Saharan Africa. One potential mechanism of this effect is via the anti-malarial effect of azithromycin, which may help treat or prevent malaria infection. This study evaluated short- and longer-term effects of azithromycin on malaria outcomes in children. Methods Children aged 8 days to 59 months were randomized in a 1:1 fashion to a single oral dose of azithromycin (20 mg/kg) or matching placebo. Children were evaluated for malaria via thin and thick smear and rapid diagnostic test (for those with tympanic temperature ≥ 37.5 °C) at baseline and 14 days and 6 months after treatment. Malaria outcomes in children receiving azithromycin versus placebo were compared at each follow-up timepoint separately. Results Of 450 children enrolled, 230 were randomized to azithromycin and 220 to placebo. Children were a median of 26 months and 51% were female, and 17% were positive for malaria parasitaemia at baseline. There was no evidence of a difference in malaria parasitaemia at 14 days or 6 months after treatment. In the azithromycin arm, 20% of children were positive for parasitaemia at 14 days compared to 17% in the placebo arm (P = 0.43) and 7.6% vs. 5.6% in the azithromycin compared to placebo arms at 6 months (P = 0.47). Conclusions Azithromycin did not affect malaria outcomes in this study, possibly due to the individually randomized nature of the trial. Trial registration This study is registered at clinicaltrials.gov (NCT03676751; registered 19 September 2018). Supplementary Information The online version contains supplementary material available at 10.1186/s12936-021-03895-9.
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Affiliation(s)
| | - Ali Sié
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | - Clarisse Dah
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | | | | | - Adama Compaoré
- Centre de Recherche en Santé de Nouna, Nouna, Burkina Faso
| | | | | | | | - Jessica M Brogdon
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA
| | - Elodie Lebas
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA
| | - Thuy Doan
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA.,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Travis C Porco
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA.,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Thomas M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA.,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA.,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA
| | - Catherine E Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, 490 Illinois St, Floor 2, San Francisco, CA, 94143, USA. .,Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA. .,Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, CA, USA.
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10
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Peric M, Pešić D, Alihodžić S, Fajdetić A, Herreros E, Gamo FJ, Angulo-Barturen I, Jiménez-Díaz MB, Ferrer-Bazaga S, Martínez MS, Gargallo-Viola D, Mathis A, Kessler A, Banjanac M, Padovan J, Bencetić Mihaljević V, Munic Kos V, Bukvić M, Eraković Haber V, Spaventi R. A novel class of fast-acting antimalarial agents: Substituted 15-membered azalides. Br J Pharmacol 2020; 178:363-377. [PMID: 33085774 PMCID: PMC9328652 DOI: 10.1111/bph.15292] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Revised: 09/01/2020] [Accepted: 10/08/2020] [Indexed: 12/18/2022] Open
Abstract
Background and Purpose Efficacy of current antimalarial treatments is declining as a result of increasing antimalarial drug resistance, so new and potent antimalarial drugs are urgently needed. Azithromycin, an azalide antibiotic, was found useful in malaria therapy, but its efficacy in humans is low. Experimental Approach Four compounds belonging to structurally different azalide classes were tested and their activities compared to azithromycin and chloroquine. in vitro evaluation included testing against sensitive and resistant Plasmodium falciparum, cytotoxicity against HepG2 cells, accumulation and retention in human erythrocytes, antibacterial activity, and mode of action studies (delayed death phenotype and haem polymerization). in vivo assessment enabled determination of pharmacokinetic profiles in mice, rats, dogs, and monkeys and in vivo efficacy in a humanized mouse model. Key Results Novel fast‐acting azalides were highly active in vitro against P. falciparum strains exhibiting various resistance patterns, including chloroquine‐resistant strains. Excellent antimalarial activity was confirmed in a P. falciparum murine model by strong inhibition of haemozoin‐containing trophozoites and quick clearance of parasites from the blood. Pharmacokinetic analysis revealed that compounds are metabolically stable and have moderate oral bioavailability, long half‐lives, low clearance, and substantial exposures, with blood cells as the preferred compartment, especially infected erythrocytes. Fast anti‐plasmodial action is achieved by the high accumulation into infected erythrocytes and interference with parasite haem polymerization, a mode of action different from slow‐acting azithromycin. Conclusion and Implications The hybrid derivatives described here represent excellent antimalarial drug candidates with the potential for clinical use in malaria therapy.
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Affiliation(s)
- Mihaela Peric
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Center for Translational and Clinical Research, Department for Intercellular Communication, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Dijana Pešić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Sulejman Alihodžić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Andrea Fajdetić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Esperanza Herreros
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,Medicines for Malaria Venture, Geneva 15, Switzerland
| | - Francisco Javier Gamo
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Iñigo Angulo-Barturen
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,The Art of Discovery, Bizkaia, Basque Country, Spain
| | - María Belén Jiménez-Díaz
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,The Art of Discovery, Bizkaia, Basque Country, Spain
| | - Santiago Ferrer-Bazaga
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - María S Martínez
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Domingo Gargallo-Viola
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain.,ABAC Therapeutics, Barcelona, Spain
| | - Amanda Mathis
- GlaxoSmithKline, Research Triangle Park, North Carolina, USA.,BioCryst Pharmaceuticals, Durham, North Carolina, USA
| | - Albane Kessler
- GlaxoSmithKline, Tres Cantos Medicines Development Campus, Diseases of the Developing World, Tres Cantos (Madrid), Spain
| | - Mihailo Banjanac
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Jasna Padovan
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | | | - Vesna Munic Kos
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Mirjana Bukvić
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Vesna Eraković Haber
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Fidelta Ltd., Zagreb, Croatia
| | - Radan Spaventi
- GlaxoSmithKline Research Centre Zagreb Ltd., Zagreb, Croatia.,Triadelta Partners Ltd, Zagreb, Croatia
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11
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Arzika AM, Maliki R, Boubacar N, Kane S, Cook CA, Lebas E, Lin Y, O'Brien KS, Austin A, Keenan JD, Lietman TM, Oldenburg CE, For The Mordor Study Group. Malaria Parasitemia and Nutritional Status during the Low Transmission Season in the Presence of Azithromycin Distribution among Preschool Children in Niger. Am J Trop Med Hyg 2020; 103:1315-1318. [PMID: 32067628 PMCID: PMC7470565 DOI: 10.4269/ajtmh.19-0547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The relationship between malaria and malnutrition is complicated, and existence of one may predispose or exacerbate the other. We evaluated the relationship between malaria parasitemia and nutritional status in children living in communities participating in a cluster-randomized trial of biannual azithromycin compared with placebo for prevention of childhood mortality. Data were collected during the low malaria transmission and low food insecurity season. Parasitemia was not associated with weight-for-height Z-score (24 months: P = 0.11 azithromycin communities, P = 0.75 placebo communities), weight-for-age Z-score (24 months: P = 0.83 azithromycin, P = 0.78 placebo), height-for-age Z-score (24 months: P = 0.30 azithromycin, P = 0.87 placebo), or mid-upper arm circumference (24 months: P = 0.12 azithromycin, P = 0.56 placebo). There was no statistically significant evidence of a difference in the relationship in communities receiving azithromycin or placebo. During the low transmission season, there was no evidence that malaria parasitemia and impaired nutritional status co-occur in children.
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Affiliation(s)
| | | | | | | | - Catherine A Cook
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Elodie Lebas
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Ying Lin
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Kieran S O'Brien
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Ariana Austin
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Jeremy D Keenan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, California.,Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Thomas M Lietman
- Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, California.,Department of Ophthalmology, University of California, San Francisco, San Francisco, California.,Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California
| | - Catherine E Oldenburg
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, California.,Department of Epidemiology & Biostatistics, University of California, San Francisco, San Francisco, California.,Department of Ophthalmology, University of California, San Francisco, San Francisco, California
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12
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Korkor CM, Garnie LF, Amod L, Egan TJ, Chibale K. Intrinsic fluorescence properties of antimalarial pyrido[1,2- a]benzimidazoles facilitate subcellular accumulation and mechanistic studies in the human malaria parasite Plasmodium falciparum. Org Biomol Chem 2020; 18:8668-8676. [PMID: 33078179 PMCID: PMC7710849 DOI: 10.1039/d0ob01730b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The intrinsic fluorescence properties of two related pyrido[1,2-a]benzimidazole antimalarial compounds suitable for the cellular imaging of the human malaria parasite Plasmodium falciparum without the need to attach extrinsic fluorophores are described. Although these compounds are structurally related, they have been shown by confocal microscopy to not only accumulate selectively within P. falciparum but to also accumulate differently in the organelles investigated. Localization to the digestive vacuole and nearby neutral lipids was observed for compound 2 which was shown to inhibit hemozoin formation using a cellular fractionation assay indicating that this is a contributing mechanism of action. By contrast, compound 1, which differs from compound 2 by the replacement of the imidazole[1,2-a:4,5-b']dipyridine core with the benzimidazole core as well as the presence of Cl substituents, shows very different localisation patterns and shows no evidence of hemozoin inhibition, suggesting a different mechanism of antimalarial action. Docking profiles of both compounds on the hemozoin surface further provided insight into their mechanisms of action.
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Affiliation(s)
- Constance M Korkor
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
| | - Larnelle F Garnie
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
| | - Leah Amod
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
| | - Timothy J Egan
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa. and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
| | - Kelly Chibale
- Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa. and South African Medical Research Council Drug Discovery and Development Research Unit, University of Cape Town, Department of Chemistry, Rondebosch 7701, South Africa and Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Rondebosch 7701, South Africa
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13
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Evaluation of the Combination of Azithromycin and Naphthoquine in Animal Malaria Models. Antimicrob Agents Chemother 2020; 64:AAC.02307-19. [DOI: 10.1128/aac.02307-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 08/18/2020] [Indexed: 11/20/2022] Open
Abstract
Combination therapy using drugs with different mechanisms of action is the current state of the art in antimalarial treatment. However, except for artemisinin-based combination therapies, only a few other combinations are now available. Increasing concern regarding the emergence and spread of artemisinin resistance in
Plasmodium falciparum
has led to a need for the development of new antimalarials. Moreover, the efficacy of current available chemoprophylaxis is compromised by drug resistance and noncompliance due to intolerable adverse effects or complicated dosing regimens.
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14
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Burns AL, Sleebs BE, Siddiqui G, De Paoli AE, Anderson D, Liffner B, Harvey R, Beeson JG, Creek DJ, Goodman CD, McFadden GI, Wilson DW. Retargeting azithromycin analogues to have dual-modality antimalarial activity. BMC Biol 2020; 18:133. [PMID: 32993629 PMCID: PMC7526119 DOI: 10.1186/s12915-020-00859-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 08/28/2020] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Resistance to front-line antimalarials (artemisinin combination therapies) is spreading, and development of new drug treatment strategies to rapidly kill Plasmodium spp. malaria parasites is urgently needed. Azithromycin is a clinically used macrolide antibiotic proposed as a partner drug for combination therapy in malaria, which has also been tested as monotherapy. However, its slow-killing 'delayed-death' activity against the parasite's apicoplast organelle and suboptimal activity as monotherapy limit its application as a potential malaria treatment. Here, we explore a panel of azithromycin analogues and demonstrate that chemical modifications can be used to greatly improve the speed and potency of antimalarial action. RESULTS Investigation of 84 azithromycin analogues revealed nanomolar quick-killing potency directed against the very earliest stage of parasite development within red blood cells. Indeed, the best analogue exhibited 1600-fold higher potency than azithromycin with less than 48 hrs treatment in vitro. Analogues were effective against zoonotic Plasmodium knowlesi malaria parasites and against both multi-drug and artemisinin-resistant Plasmodium falciparum lines. Metabolomic profiles of azithromycin analogue-treated parasites suggested activity in the parasite food vacuole and mitochondria were disrupted. Moreover, unlike the food vacuole-targeting drug chloroquine, azithromycin and analogues were active across blood-stage development, including merozoite invasion, suggesting that these macrolides have a multi-factorial mechanism of quick-killing activity. The positioning of functional groups added to azithromycin and its quick-killing analogues altered their activity against bacterial-like ribosomes but had minimal change on 'quick-killing' activity. Apicoplast minus parasites remained susceptible to both azithromycin and its analogues, further demonstrating that quick-killing is independent of apicoplast-targeting, delayed-death activity. CONCLUSION We show that azithromycin and analogues can rapidly kill malaria parasite asexual blood stages via a fast action mechanism. Development of azithromycin and analogues as antimalarials offers the possibility of targeting parasites through both a quick-killing and delayed-death mechanism of action in a single, multifactorial chemotype.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Brad E Sleebs
- Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, 3050, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, Victoria, 3050, Australia
| | - Ghizal Siddiqui
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Amanda E De Paoli
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Dovile Anderson
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Benjamin Liffner
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - Richard Harvey
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, 3004, Australia
- Department of Medicine, University of Melbourne, Melbourne, Australia
- Central Clinical School and Department of Microbiology, Monash University, Melbourne, Australia
| | - Darren J Creek
- Monash Institute of Pharmaceutical Sciences, Monash University, Melbourne, Victoria, 3052, Australia
| | - Christopher D Goodman
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Geoffrey I McFadden
- School of Biosciences, University of Melbourne, Melbourne, Victoria, 3010, Australia
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, The University of Adelaide, Adelaide, 5005, Australia.
- Burnet Institute, Melbourne, Victoria, 3004, Australia.
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15
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An open label study of the safety and efficacy of a single dose of weekly chloroquine and azithromycin administered for malaria prophylaxis in healthy adults challenged with 7G8 chloroquine-resistant Plasmodium falciparum in a controlled human malaria infection model. Malar J 2020; 19:336. [PMID: 32938444 PMCID: PMC7493140 DOI: 10.1186/s12936-020-03409-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 09/04/2020] [Indexed: 11/15/2022] Open
Abstract
Background Malaria remains the top infectious disease threat facing the U.S. military in many forward operating environments. Compliance with malaria chemoprophylaxis remains a critical component in preventing malaria in the deployed Service Member. Studies of previous military operations show that compliance is consistently higher with weekly versus daily dosing regimens. Current FDA approved weekly chemoprophylaxis options have contraindications that can limit prescribing. The combination of chloroquine (CQ) with azithromycin (AZ) has previously been shown to be an efficacious treatment option for malaria, has pharmacokinetics compatible with weekly dosing, and has shown synergy when combined in vitro. Methods In this open label study, 18 healthy volunteers, aged 18–50 years (inclusive), were randomly assigned to receive either 300 mg CQ or 300 mg CQ and 2 gm azithromycin (CQAZ) of directly observed therapy, weekly for 3 weeks prior to undergoing mosquito bite challenge with chloroquine-resistant Plasmodium falciparum. Volunteers that remained asymptomatic and had no evidence of parasitaemia continued to receive weekly post-exposure chemoprophylaxis for 3 weeks following malaria challenge. The primary endpoint was the number of volunteers that remained asymptomatic and had no evidence of parasitaemia 28 days after the malaria challenge. Results All 6 (100%) volunteers randomized to the CQ control group became symptomatic with parasitaemia during the 28-day post-challenge period. Only 1/12 (8.3%) of volunteers in the CQAZ group developed symptoms and parasitaemia during the 28-day post-challenge period. However, after chemoprophylaxis was discontinued an additional 6 volunteers developed parasitaemia between days 28–41 after challenge, with 4 of 6 experiencing symptoms. 80% of subjects in the CQAZ group experienced treatment related gastrointestinal adverse events (including 13% that experienced severe nausea) compared to 38% in the CQ group. A comparison of the pharmacokinetics in the CQAZ group demonstrated higher azithromycin Cmax (p = 0.03) and AUC (p = 0.044) levels in those volunteers who never became parasitaemic compared to those who did. Conclusion Given the high rate of side effects and poor efficacy when administered for 3 weeks before and after challenge, the combination of weekly chloroquine and azithromycin is a suboptimal regimen combination for weekly malaria chemoprophylaxis. Trial registration ClinicalTrials.gov NCT03278808
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16
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Repurposing Drugs to Fight Hepatic Malaria Parasites. Molecules 2020; 25:molecules25153409. [PMID: 32731386 PMCID: PMC7435416 DOI: 10.3390/molecules25153409] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/23/2020] [Accepted: 07/24/2020] [Indexed: 12/16/2022] Open
Abstract
Malaria remains one of the most prevalent infectious diseases worldwide, primarily affecting some of the most vulnerable populations around the globe. Despite achievements in the treatment of this devastating disease, there is still an urgent need for the discovery of new drugs that tackle infection by Plasmodium parasites. However, de novo drug development is a costly and time-consuming process. An alternative strategy is to evaluate the anti-plasmodial activity of compounds that are already approved for other purposes, an approach known as drug repurposing. Here, we will review efforts to assess the anti-plasmodial activity of existing drugs, with an emphasis on the obligatory and clinically silent liver stage of infection. We will also review the current knowledge on the classes of compounds that might be therapeutically relevant against Plasmodium in the context of other communicable diseases that are prevalent in regions where malaria is endemic. Repositioning existing compounds may constitute a faster solution to the current gap of prophylactic and therapeutic drugs that act on Plasmodium parasites, overall contributing to the global effort of malaria eradication.
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17
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Biannual versus annual mass azithromycin distribution and malaria seroepidemiology among preschool children in Niger: a sub-study of a cluster randomized trial. Malar J 2019; 18:389. [PMID: 31796025 PMCID: PMC6889587 DOI: 10.1186/s12936-019-3033-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 11/24/2019] [Indexed: 12/02/2022] Open
Abstract
Background Biannual mass azithromycin administration to preschool children reduces all-cause mortality, but the mechanism for the effect is not understood. Azithromycin has activity against malaria parasites, and malaria is a leading cause of child mortality in the Sahel. The effect of biannual versus annual azithromycin distribution for trachoma control on serological response to merozoite surface protein 1 (MSP-119), a surrogate for malaria incidence, was evaluated among children in Niger. Methods Markers of malaria exposure were measured in two arms of a factorial randomized controlled trial designed to evaluate targeted biannual azithromycin distribution to children under 12 years of age compared to annual azithromycin to the entire community for trachoma control (N = 12 communities per arm). Communities were treated for 36 months (6 versus 3 distributions). Dried blood spots were collected at 36 months among children ages 1–5 years, and MSP-119 antibody levels were assessed using a bead-based multiplex assay to measure malaria seroprevalence. Results Antibody results were available for 991 children. MSP-119 seropositivity was 62.7% in the biannual distribution arm compared to 68.7% in the annual arm (prevalence ratio 0.91, 95% CI 0.83 to 1.00). Mean semi-quantitative antibody levels were lower in the biannual distribution arm compared to the annual arm (mean difference − 0.39, 95% CI − 0.05 to − 0.72). Conclusions Targeted biannual azithromycin distribution was associated with lower malaria seroprevalence compared to that in a population that received annual distribution. Trial Registration Clinicaltrials.gov NCT00792922
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18
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Bloch EM, Munoz B, Mrango Z, Weaver J, Mboera LEG, Lietman TM, Sullivan DJ, West SK. The impact on malaria of biannual treatment with azithromycin in children age less than 5 years: a prospective study. Malar J 2019; 18:284. [PMID: 31443654 PMCID: PMC6708241 DOI: 10.1186/s12936-019-2914-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Accepted: 08/17/2019] [Indexed: 01/01/2023] Open
Abstract
Background The MORDOR study, a cluster randomized clinical trial, showed that single-dose azithromycin (20 mg/kg) administered biannually for 2 years to preschool children reduced mortality; a study was conducted to determine its effect on clinical symptomatic episodes of malaria as a potential mechanism for mortality benefit. Methods A randomized control trial (RCT) was conducted, whereby 30 randomly selected communities in Kilosa District, Tanzania were randomized to receive 6-monthly treatment of children ages 1–59 months with single-dose azithromycin (20 mg/kg) vs. placebo. A prospective cohort study was nested within the RCT: children, aged 1 to 35 months at baseline, were randomly selected in each community and evaluated at 6-monthly intervals for 2 years. At each visit, the children were assessed for recent or ongoing fever and anti-malarial treatment; a rapid diagnostic test (RDT) for malaria was performed. The two major outcomes of interest were prevalence of RDT positivity and clinical malaria. The latter was defined as RDT-positivity with fever at time of evaluation and/or reported fever in the 3 days prior to evaluation. Methods that account for correlations at community level and within individuals over time were used to evaluate associations. Results At baseline, the prevalence rates in the children in the azithromycin and placebo arms were 17.6% vs. 15.5% for RDT positivity (p = 0.76) and 6.1% vs. 4.3% (p = 0.56) for clinical malaria. There was a decline in both RDT-positivity and clinical malaria over time in both arms. The difference by treatment assignment was not significant for clinical malaria; it was significant for RDT-positivity with greater odds of decline in the placebo arm (p = 0.01). Conclusions Lack of evidence for a significant difference in the prevalence of clinical malaria in children at any visit following treatment suggests that the effect of single-dose azithromycin on malaria is at best transient and limited in scope. Chance overrepresentation of non-seasonal transmission in the communities in the azithromycin arm may account for higher rates of RDT-positivity and less decline over time. Trial registration Clinicaltrials.gov NCT02047981
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Affiliation(s)
- Evan M Bloch
- Department of Pathology, Johns Hopkins School of Medicine, 600 N. Wolfe St/Carnegie 446 D1, Baltimore, MD, 21287, USA.
| | - Beatriz Munoz
- Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Zakayo Mrango
- National Institute for Medical Research, Kilosa, Tanzania
| | - Jerusha Weaver
- Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | - Tom M Lietman
- Francis I Proctor Foundation, University of California, San Francisco, San Francisco, CA, USA
| | - David J Sullivan
- Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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19
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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: 23] [Impact Index Per Article: 4.6] [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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20
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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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21
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Burns AL, Dans MG, Balbin JM, de Koning-Ward TF, Gilson PR, Beeson JG, Boyle MJ, Wilson DW. Targeting malaria parasite invasion of red blood cells as an antimalarial strategy. FEMS Microbiol Rev 2019; 43:223-238. [PMID: 30753425 PMCID: PMC6524681 DOI: 10.1093/femsre/fuz005] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Accepted: 02/11/2019] [Indexed: 12/20/2022] Open
Abstract
Plasmodium spp. parasites that cause malaria disease remain a significant global-health burden. With the spread of parasites resistant to artemisinin combination therapies in Southeast Asia, there is a growing need to develop new antimalarials with novel targets. Invasion of the red blood cell by Plasmodium merozoites is essential for parasite survival and proliferation, thus representing an attractive target for therapeutic development. Red blood cell invasion requires a co-ordinated series of protein/protein interactions, protease cleavage events, intracellular signals, organelle release and engagement of an actin-myosin motor, which provide many potential targets for drug development. As these steps occur in the bloodstream, they are directly susceptible and exposed to drugs. A number of invasion inhibitors against a diverse range of parasite proteins involved in these different processes of invasion have been identified, with several showing potential to be optimised for improved drug-like properties. In this review, we discuss red blood cell invasion as a drug target and highlight a number of approaches for developing antimalarials with invasion inhibitory activity to use in future combination therapies.
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Affiliation(s)
- Amy L Burns
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | - Madeline G Dans
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Deakin University, School of Medicine, Waurn Ponds, Victoria, Australia 3216
| | - Juan M Balbin
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005
| | | | - Paul R Gilson
- Burnet Institute, Melbourne, Victoria, Australia 3004
| | - James G Beeson
- Burnet Institute, Melbourne, Victoria, Australia 3004.,Central Clinical School and Department of Microbiology, Monash University 3004.,Department of Medicine, University of Melbourne, Australia 3052
| | - Michelle J Boyle
- Burnet Institute, Melbourne, Victoria, Australia 3004.,QIMR Berghofer Medical Research Institute, Herston, Queensland, Australia 4006
| | - Danny W Wilson
- Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, Australia 5005.,Burnet Institute, Melbourne, Victoria, Australia 3004
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22
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Simon MS, Westblade LF, Dziedziech A, Visone JE, Furman RR, Jenkins SG, Schuetz AN, Kirkman LA. Clinical and Molecular Evidence of Atovaquone and Azithromycin Resistance in Relapsed Babesia microti Infection Associated With Rituximab and Chronic Lymphocytic Leukemia. Clin Infect Dis 2019; 65:1222-1225. [PMID: 28541469 DOI: 10.1093/cid/cix477] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 05/22/2017] [Indexed: 11/15/2022] Open
Abstract
Babesiosis treatment failures with standard therapy have been reported, but the molecular mechanisms are not well understood. We describe the emergence of atovaquone and azithromycin resistance associated with mutations in the binding regions of the target proteins of both drugs during treatment of an immunosuppressed patient with relapsing babesiosis.
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Affiliation(s)
| | | | | | | | - Richard R Furman
- Department of Medicine, Division of Hematology Oncology, Weill Cornell Medicine,New York, New York; and
| | | | - Audrey N Schuetz
- Mayo Clinic, Department of Laboratory Medicine and Pathology, Rochester, Minnesota
| | - Laura A Kirkman
- Department of Medicine, Division of Infectious Diseases
- Department of Microbiology and Immunology, and
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23
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Biannual mass azithromycin distributions and malaria parasitemia in pre-school children in Niger: A cluster-randomized, placebo-controlled trial. PLoS Med 2019; 16:e1002835. [PMID: 31237871 PMCID: PMC6592520 DOI: 10.1371/journal.pmed.1002835] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/21/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mass azithromycin distributions have been shown to reduce mortality in preschool children, although the factors mediating this mortality reduction are not clear. This study was performed to determine whether mass distribution of azithromycin, which has modest antimalarial activity, reduces the community burden of malaria. METHODS AND FINDINGS In a cluster-randomized trial conducted from 23 November 2014 until 31 July 2017, 30 rural communities in Niger were randomized to 2 years of biannual mass distributions of either azithromycin (20 mg/kg oral suspension) or placebo to children aged 1 to 59 months. Participants, field staff, and investigators were masked to treatment allocation. The primary malaria outcome was the community prevalence of parasitemia on thick blood smear, assessed in a random sample of children from each community at study visits 12 and 24 months after randomization. Analyses were performed in an intention-to-treat fashion. At the baseline visit, a total of 1,695 children were enumerated in the 15 azithromycin communities, and 3,029 children were enumerated in the 15 placebo communities. No communities were lost to follow-up. The mean prevalence of malaria parasitemia at baseline was 8.9% (95% CI 5.1%-15.7%; 52 of 552 children across all communities) in the azithromycin-treated group and 6.7% (95% CI 4.0%-12.6%; 36 of 542 children across all communities) in the placebo-treated group. In the prespecified primary analysis, parasitemia was lower in the azithromycin-treated group at month 12 (mean prevalence 8.8%, 95% CI 5.1%-14.3%; 51 of 551 children across all communities) and month 24 (mean 3.5%, 95% CI 1.9%-5.5%; 21 of 567 children across all communities) than it was in the placebo-treated group at month 12 (mean 15.3%, 95% CI 10.8%-20.6%; 81 of 548 children across all communities) and month 24 (mean 4.8%, 95% CI 3.3%-6.4%; 28 of 592 children across all communities) (P = 0.02). Communities treated with azithromycin had approximately half the odds of parasitemia compared to those treated with placebo (odds ratio [OR] 0.54, 95% CI 0.30 to 0.97). Parasite density was lower in the azithromycin group than the placebo group at 12 and 24 months (square root-transformed outcome; density estimates were 7,540 parasites/μl lower [95% CI -350 to -12,550 parasites/μl; P = 0.02] at a mean parasite density of 17,000, as was observed in the placebo arm). No significant difference in hemoglobin was observed between the 2 treatment groups at 12 and 24 months (mean 0.34 g/dL higher in the azithromycin arm, 95% CI -0.06 to 0.75 g/dL; P = 0.10). No serious adverse events were reported in either group, and among children aged 1 to 5 months, the most commonly reported nonserious adverse events (i.e., diarrhea, vomiting, and rash) were less common in the azithromycin-treated communities. Limitations of the trial include the timing of the treatments and monitoring visits, both of which took place before the peak malaria season, as well as the uncertain generalizability to areas with different malaria transmission dynamics. CONCLUSIONS Mass azithromycin distributions were associated with a reduced prevalence of malaria parasitemia in this trial, suggesting one possible mechanism for the mortality benefit observed with this intervention. TRIAL REGISTRATION The trial was registered on ClinicalTrials.gov (NCT02048007).
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24
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Virji AZ, Thekkiniath J, Ma W, Lawres L, Knight J, Swei A, Roch KL, Mamoun CB. Insights into the evolution and drug susceptibility of Babesia duncani from the sequence of its mitochondrial and apicoplast genomes. Int J Parasitol 2019; 49:105-113. [PMID: 30176236 PMCID: PMC6395566 DOI: 10.1016/j.ijpara.2018.05.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/04/2018] [Accepted: 05/03/2018] [Indexed: 11/22/2022]
Abstract
Babesia microti and Babesia duncani are the main causative agents of human babesiosis in the United States. While significant knowledge about B. microti has been gained over the past few years, nothing is known about B. duncani biology, pathogenesis, mode of transmission or sensitivity to currently recommended therapies. Studies in immunocompetent wild type mice and hamsters have shown that unlike B. microti, infection with B. duncani results in severe pathology and ultimately death. The parasite factors involved in B. duncani virulence remain unknown. Here we report the first known completed sequence and annotation of the apicoplast and mitochondrial genomes of B. duncani. We found that the apicoplast genome of this parasite consists of a 34 kb monocistronic circular molecule encoding functions that are important for apicoplast gene transcription as well as translation and maturation of the organelle's proteins. The mitochondrial genome of B. duncani consists of a 5.9 kb monocistronic linear molecule with two inverted repeats of 48 bp at both ends. Using the conserved cytochrome b (Cytb) and cytochrome c oxidase subunit I (coxI) proteins encoded by the mitochondrial genome, phylogenetic analysis revealed that B. duncani defines a new lineage among apicomplexan parasites distinct from B. microti, Babesia bovis, Theileria spp. and Plasmodium spp. Annotation of the apicoplast and mitochondrial genomes of B. duncani identified targets for development of effective therapies. Our studies set the stage for evaluation of the efficacy of these drugs alone or in combination against B. duncani in culture as well as in animal models.
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Affiliation(s)
- Azan Z Virji
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520, USA
| | - Jose Thekkiniath
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520, USA
| | - Wenxiu Ma
- Department of Statistics, University of California, 900 University Avenue, Riverside, CA 92521, USA
| | - Lauren Lawres
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520, USA
| | - James Knight
- Department of Genetics, Yale School of Medicine, New Haven, CT 06520, USA
| | - Andrea Swei
- Department of Biology, San Francisco State University, 1600 Holloway Ave, San Francisco, CA 94132, USA
| | - Karine Le Roch
- Department of Cell Biology & Neuroscience, 900 University Avenue, University of California, Riverside, CA 92521, USA
| | - Choukri Ben Mamoun
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520, USA.
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25
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Gao C, Guo Z, Lu X, Chen H, Liu L, Yu Z, Chen Y. Hexaricins, Pradimicin-like Polyketides from a Marine Sediment-Derived Streptosporangium sp. and Their Antioxidant Effects. JOURNAL OF NATURAL PRODUCTS 2018; 81:2069-2074. [PMID: 30178674 DOI: 10.1021/acs.jnatprod.8b00397] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Seven pradimicin-like polyketides were isolated from the dichloromethane extract of the marine sediment-derived Streptosporangium sp. CGMCC 4.7309, including five new hexaricins, D-H (1-5), and known hexaricins A (6) and C (7). Their structures were determined by HRESIMS, 1D and 2D NMR, and other spectroscopic analyses. The absolute configurations of compounds 1-5 were determined on the basis of circular dichroism and specific rotation data. All isolated compounds 1-7 were tested for their antioxidant capacities by DPPH• scavenging, •OH scavenging, and •O2̅ scavenging assays. Compounds 3 and 4 displayed stronger antioxidant activities than the positive control ( tert-butylhydroquinone). The relationship between structure and antioxidant activity is discussed. These compounds could be effective natural antioxidants with considerable pharmaceutical value.
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Affiliation(s)
- Chunzhi Gao
- College of Plant Protection , Shenyang Agricultural University , Shenyang 110866 , People's Republic of China
| | - Zhengyan Guo
- Institute of Microbiology , University of Chinese Academy of Sciences , Beijing 100101 , People's Republic of China
| | - Xingzhong Lu
- Liaoning Baihao Biotech Company Ltd , Benxi 117000 , People's Republic of China
| | - Haiyan Chen
- Key Laboratory of Applied Chemistry Technology and Resource Development , Medical College of Guangxi University, Guangxi Colleges and Universities , Nanning 530004 , People's Republic of China
| | - Liwei Liu
- Institute of Microbiology , University of Chinese Academy of Sciences , Beijing 100101 , People's Republic of China
| | - Zhiguo Yu
- College of Plant Protection , Shenyang Agricultural University , Shenyang 110866 , People's Republic of China
| | - Yihua Chen
- Institute of Microbiology , University of Chinese Academy of Sciences , Beijing 100101 , People's Republic of China
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26
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O'Brien KS, Amza A, Kadri B, Nassirou B, Cotter SY, Stoller NE, West SK, Bailey RL, Porco TC, Gaynor BD, Lietman TM, Oldenburg CE. Anthropometry and Malaria among Children in Niger: A Cross-Sectional Study. Am J Trop Med Hyg 2018; 99:665-669. [PMID: 30014814 DOI: 10.4269/ajtmh.18-0214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The complex relationship between malnutrition and malaria affects morbidity and mortality in children younger than 5 years, particularly in parts of sub-Saharan Africa where these conditions occur together seasonally. Previous research on this relationship has been inconclusive. Here, we examine the association between anthropometric indicators and malaria infection in a population-based sample of children younger than 5 years in Niger. This cross-sectional study is a secondary analysis of a cluster-randomized trial comparing treatment strategies for trachoma in Niger. We included children aged 6-60 months residing in the 48 communities enrolled in the trial who completed anthropometric and malaria infection assessments at the final study visit. We evaluated the association between anthropometric indicators, including height-for-age z-score (HAZ) and weight-for-age z-score (WAZ) and indicators of malaria infection, including malaria parasitemia and clinical malaria. In May 2013, we collected data from 1,649 children. Of these, 780 (47.3%) were positive for malaria parasitemia and 401 (24.3%) had clinical malaria. In models of malaria parasitemia, the adjusted odds ratio (aOR) was 1.05 (95% confidence interval [CI]: 1.00-1.10) for HAZ and 1.07 (95% CI: 0.99, 1.15) for WAZ. In models of clinical malaria, the aOR was 1.07 (95% CI: 1.02-1.11) for HAZ and 1.09 (95% CI: 1.01-1.19) for WAZ. Overall, we did not find evidence of an association between most anthropometric indicators and malaria infection. Greater height may be associated with an increased risk of clinical malaria.
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Affiliation(s)
- Kieran S O'Brien
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Abdou Amza
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger
| | - Boubacar Kadri
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger
| | - Baido Nassirou
- Programme FSS/Université Abdou Moumouni de Niamey, Programme National de Santé Oculaire, Niamey, Niger
| | - Sun Y Cotter
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Nicole E Stoller
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Sheila K West
- Dana Center for Preventive Ophthalmology, Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland
| | - Robin L Bailey
- Department of Infectious and Tropical Diseases, Clinical Research Unit, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Travis C Porco
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California.,Department of Ophthalmology, University of California San Francisco, San Francisco, California.,Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Bruce D Gaynor
- Department of Ophthalmology, University of California San Francisco, San Francisco, California.,Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Thomas M Lietman
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California.,Department of Ophthalmology, University of California San Francisco, San Francisco, California.,Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California
| | - Catherine E Oldenburg
- Francis I. Proctor Foundation, University of California San Francisco, San Francisco, California.,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California
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27
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Randomized, Double-Blind, Placebo-Controlled Studies to Assess Safety and Prophylactic Efficacy of Naphthoquine-Azithromycin Combination for Malaria Prophylaxis in Southeast Asia. Antimicrob Agents Chemother 2018; 62:AAC.00793-18. [PMID: 29987144 DOI: 10.1128/aac.00793-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 07/05/2018] [Indexed: 01/01/2023] Open
Abstract
New prophylactic drugs against malaria infections are urgently needed. We conducted randomized, double-blind, placebo-controlled, phase 2 trials of a new antimalarial drug combination, naphthoquine-azithromycin (NQAZ), to determine its safety and protective efficacy in a low-endemicity area of Southeast Asia. In the first trial, 127 healthy volunteers were randomized to receive two single doses of either 400 mg of NQAZ (200 mg of each drug), 800 mg of NQAZ (400 mg of each drug), or placebo on day 0 and day 30. Weekly follow-ups were performed for 2 months, and physical and clinical laboratory exams were done during the second and eighth week. Both drug regimens were well tolerated, without any serious adverse events. Four adverse events (transient and slight elevations of serum transaminase concentrations) were found only in the two drug-treated groups and thus might be drug-related. In the second trial, 353 volunteer villagers were randomized into the same three groups as in the first trial, and malaria infections were followed for a month. For the intention-to-treat analysis, both regimens offered greater than 90% prophylactic efficacies against all malaria infections. When the analysis was done according to parasite species, 400 mg and 800 mg NQAZ provided 81.63 and 90.59% prophylactic efficacies, respectively, against Plasmodium falciparum infections, whereas both offered 100% prophylactic efficacy against Plasmodium vivax and Plasmodium ovale These trials showed that NQAZ had a good safety profile, and monthly single doses of 400 mg or 800 mg for adults offered excellent prophylaxis against malaria infections, especially the two relapsing species.
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28
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Annual Versus Biannual Mass Azithromycin Distribution and Malaria Parasitemia During the Peak Transmission Season Among Children in Niger. Pediatr Infect Dis J 2018; 37:506-510. [PMID: 29088030 PMCID: PMC5924654 DOI: 10.1097/inf.0000000000001813] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Azithromycin has modest efficacy against malaria, and previous cluster randomized trials have suggested that mass azithromycin distribution for trachoma control may play a role in malaria control. We evaluated the effect of annual versus biannual mass azithromycin distribution over a 3-year period on malaria prevalence during the peak transmission season in a region with seasonal malaria transmission in Niger. METHODS Twenty-four communities in Matameye, Niger, were randomized to annual mass azithromycin distribution (3 distributions to the entire community during the peak transmission season) or biannual-targeted azithromycin distribution (6 distributions to children <12 years of age, including 3 in the peak transmission season and 3 in the low transmission season). Malaria indices were evaluated at 36 months during the high transmission season. RESULTS Parasitemia prevalence was 42.6% (95% confidence interval: 31.7%-53.6%) in the biannual distribution arm compared with 50.6% (95% confidence interval: 40.3%-60.8%) in the annual distribution arm (P = 0.29). There was no difference in parasite density or hemoglobin concentration in the 2 treatment arms. CONCLUSIONS Additional rounds of mass azithromycin distribution during low transmission may not have a significant impact on malaria parasitemia measured during the peak transmission season.
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29
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Buedenbender L, Robertson LP, Lucantoni L, Avery VM, Kurtböke Dİ, Carroll AR. HSQC-TOCSY Fingerprinting-Directed Discovery of Antiplasmodial Polyketides from the Marine Ascidian-Derived Streptomyces sp. (USC-16018). Mar Drugs 2018; 16:md16060189. [PMID: 29849004 PMCID: PMC6025042 DOI: 10.3390/md16060189] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 05/18/2018] [Accepted: 05/22/2018] [Indexed: 12/17/2022] Open
Abstract
Chemical investigations on the fermentation extract obtained from an ascidian-derived Streptomyces sp. (USC-16018) yielded a new ansamycin polyketide, herbimycin G (1), as well as a known macrocyclic polyketide, elaiophylin (2), and four known diketopiperazines (3–6). The structures of the compounds were elucidated based on 1D/2D NMR and MS data. The absolute configuration of 1 was established by comparison of experimental and predicted electronic circular dichroism (ECD) data. Antiplasmodial activities were tested for the natural products against chloroquine sensitive (3D7) and chloroquine resistant (Dd2) Plasmodium falciparum strains; the two polyketides (1–2) demonstrated an inhibition of >75% against both parasite strains and while 2 was highly cytotoxic, herbimycin G (1) showed no cytotoxicity and good predicted water solubility.
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Affiliation(s)
- Larissa Buedenbender
- Environmental Futures Research Institute, School of Environment and Science, Griffith University, Gold Coast Campus, QLD 4222, Australia.
| | - Luke P Robertson
- Environmental Futures Research Institute, School of Environment and Science, Griffith University, Gold Coast Campus, QLD 4222, Australia.
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia.
| | - Leonardo Lucantoni
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia.
| | - Vicky M Avery
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia.
| | - D İpek Kurtböke
- GeneCology Research Centre, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, QLD 4558, Australia.
| | - Anthony R Carroll
- Environmental Futures Research Institute, School of Environment and Science, Griffith University, Gold Coast Campus, QLD 4222, Australia.
- Griffith Institute for Drug Discovery, Griffith University, Brisbane, QLD 4111, Australia.
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30
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Buedenbender L, Habener LJ, Grkovic T, Kurtböke Dİ, Duffy S, Avery VM, Carroll AR. HSQC-TOCSY Fingerprinting for Prioritization of Polyketide- and Peptide-Producing Microbial Isolates. JOURNAL OF NATURAL PRODUCTS 2018; 81:957-965. [PMID: 29498849 DOI: 10.1021/acs.jnatprod.7b01063] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Microbial products are a promising source for drug leads as a result of their unique structural diversity. However, reisolation of already known natural products significantly hampers the discovery process, and it is therefore important to incorporate effective microbial isolate selection and dereplication protocols early in microbial natural product studies. We have developed a systematic approach for prioritization of microbial isolates for natural product discovery based on heteronuclear single-quantum correlation-total correlation spectroscopy (HSQC-TOCSY) nuclear magnetic resonance profiles in combination with antiplasmodial activity of extracts. The HSQC-TOCSY experiments allowed for unfractionated microbial extracts containing polyketide and peptidic natural products to be rapidly identified. Here, we highlight how this approach was used to prioritize extracts derived from a library of 119 ascidian-associated actinomycetes that possess a higher potential to produce bioactive polyketides and peptides.
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Affiliation(s)
- Larissa Buedenbender
- Environmental Futures Research Institute , Griffith University , Gold Coast Campus, Southport , Queensland 4222 , Australia
| | - Leesa J Habener
- Environmental Futures Research Institute , Griffith University , Gold Coast Campus, Southport , Queensland 4222 , Australia
| | - Tanja Grkovic
- Natural Products Support Group, Leidos Biomedical Research, Incorporated , Frederick National Laboratory for Cancer Research , Frederick , Maryland 21702 , United States
| | - D İpek Kurtböke
- Genecology Research Centre, Faculty of Science, Health, Education and Engineering , University of the Sunshine Coast , Maroochydore , Queensland 4558 , Australia
| | - Sandra Duffy
- Griffith Institute for Drug Discovery , Griffith University , Nathan Campus, Brisbane , Queensland 4111 , Australia
| | - Vicky M Avery
- Griffith Institute for Drug Discovery , Griffith University , Nathan Campus, Brisbane , Queensland 4111 , Australia
| | - Anthony R Carroll
- Environmental Futures Research Institute , Griffith University , Gold Coast Campus, Southport , Queensland 4222 , Australia
- Griffith Institute for Drug Discovery , Griffith University , Nathan Campus, Brisbane , Queensland 4111 , Australia
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31
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Validation of Putative Apicoplast-Targeting Drugs Using a Chemical Supplementation Assay in Cultured Human Malaria Parasites. Antimicrob Agents Chemother 2017; 62:AAC.01161-17. [PMID: 29109165 DOI: 10.1128/aac.01161-17] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 10/18/2017] [Indexed: 11/20/2022] Open
Abstract
Malaria parasites contain a relict plastid, the apicoplast, which is considered an excellent drug target due to its bacterial-like ancestry. Numerous parasiticidals have been proposed to target the apicoplast, but few have had their actual targets substantiated. Isopentenyl pyrophosphate (IPP) production is the sole required function of the apicoplast in the blood stage of the parasite life cycle, and IPP supplementation rescues parasites from apicoplast-perturbing drugs. Hence, any drug that kills parasites when IPP is supplied in culture must have a nonapicoplast target. Here, we use IPP supplementation to discriminate whether 23 purported apicoplast-targeting drugs are on- or off-target. We demonstrate that a prokaryotic DNA replication inhibitor (ciprofloxacin), several prokaryotic translation inhibitors (chloramphenicol, doxycycline, tetracycline, clindamycin, azithromycin, erythromycin, and clarithromycin), a tRNA synthase inhibitor (mupirocin), and two IPP synthesis pathway inhibitors (fosmidomycin and FR900098) have apicoplast targets. Intriguingly, fosmidomycin and FR900098 leave the apicoplast intact, whereas the others eventually result in apicoplast loss. Actinonin, an inhibitor of bacterial posttranslational modification, does not produce a typical delayed-death response but is rescued with IPP, thereby confirming its apicoplast target. Parasites treated with putative apicoplast fatty acid pathway inhibitors could not be rescued, demonstrating that these drugs have their primary targets outside the apicoplast, which agrees with the dispensability of the apicoplast fatty acid synthesis pathways in the blood stage of malaria parasites. IPP supplementation provides a simple test of whether a compound has a target in the apicoplast and can be used to screen novel compounds for mode of action.
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32
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Amberg-Johnson K, Hari SB, Ganesan SM, Lorenzi HA, Sauer RT, Niles JC, Yeh E. Small molecule inhibition of apicomplexan FtsH1 disrupts plastid biogenesis in human pathogens. eLife 2017; 6:29865. [PMID: 28826494 PMCID: PMC5576918 DOI: 10.7554/elife.29865] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/17/2017] [Indexed: 12/21/2022] Open
Abstract
The malaria parasite Plasmodium falciparum and related apicomplexan pathogens contain an essential plastid organelle, the apicoplast, which is a key anti-parasitic target. Derived from secondary endosymbiosis, the apicoplast depends on novel, but largely cryptic, mechanisms for protein/lipid import and organelle inheritance during parasite replication. These critical biogenesis pathways present untapped opportunities to discover new parasite-specific drug targets. We used an innovative screen to identify actinonin as having a novel mechanism-of-action inhibiting apicoplast biogenesis. Resistant mutation, chemical-genetic interaction, and biochemical inhibition demonstrate that the unexpected target of actinonin in P. falciparum and Toxoplasma gondii is FtsH1, a homolog of a bacterial membrane AAA+ metalloprotease. PfFtsH1 is the first novel factor required for apicoplast biogenesis identified in a phenotypic screen. Our findings demonstrate that FtsH1 is a novel and, importantly, druggable antimalarial target. Development of FtsH1 inhibitors will have significant advantages with improved drug kinetics and multistage efficacy against multiple human parasites.
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Affiliation(s)
- Katherine Amberg-Johnson
- Department of Biochemistry, Stanford Medical School, Stanford, United States.,Microbiology and Immunology, Stanford Medical School, Stanford, United States
| | - Sanjay B Hari
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Suresh M Ganesan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States
| | - Hernan A Lorenzi
- Department of Infectious Disease, The J. Craig Venter Institute, Maryland, United States
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, United States
| | - Jacquin C Niles
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, United States
| | - Ellen Yeh
- Department of Biochemistry, Stanford Medical School, Stanford, United States.,Microbiology and Immunology, Stanford Medical School, Stanford, United States.,Department of Pathology, Stanford Medical School, Stanford, United States
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Salman S, Baiwog F, Page-Sharp M, Griffin S, Karunajeewa HA, Mueller I, Rogerson SJ, Siba PM, Ilett KF, Davis TME. Optimal Antimalarial Dose Regimens for Sulfadoxine-Pyrimethamine with or without Azithromycin in Pregnancy Based on Population Pharmacokinetic Modeling. Antimicrob Agents Chemother 2017; 61:e02291-16. [PMID: 28242669 PMCID: PMC5404578 DOI: 10.1128/aac.02291-16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 02/20/2017] [Indexed: 01/19/2023] Open
Abstract
Optimal dosing of sulfadoxine-pyrimethamine (SP) as intermittent preventive treatment in pregnancy remains to be established, particularly when coadministered with azithromycin (AZI). To further characterize SP pharmacokinetics in pregnancy, plasma concentration-time data from 45 nonpregnant and 45 pregnant women treated with SP-AZI (n = 15 in each group) and SP-chloroquine (n = 30 in each group) were analyzed. Population nonlinear mixed-effect pharmacokinetic models were developed for pyrimethamine (PYR), sulfadoxine (SDOX), and N-acetylsulfadoxine (the SDOX metabolite NASDOX), and potential covariates were included. Pregnancy increased the relative clearance (CL/F) of PYR, SDOX, and NASDOX by 48, 29, and 70%, respectively, as well as the relative volumes of distribution (V/F) of PYR (46 and 99%) and NASDOX (46%). Coadministration of AZI resulted in a greater increase in PYR CL/F (80%) and also increased NASDOX V/F by 76%. Apparent differences between these results and those of published studies of SP disposition may reflect key differences in study design, including the use of an early postpartum follow-up study rather than a nonpregnant comparator group. Simulations based on the final population model demonstrated that, compared to conventional single-dose SP in nonpregnant women, two such doses given 24 h apart should ensure that pregnant women have similar drug exposure, while three daily SP doses may be required if SP is given with AZI. The results of past and ongoing trials using recommended adult SP doses with or without AZI in pregnant women may need to be interpreted in light of these findings and consideration given to using increased doses in future trials.
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Affiliation(s)
- Sam Salman
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
| | - Francisca Baiwog
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Madhu Page-Sharp
- School of Pharmacy, Curtin University of Technology, Bentley, Western Australia, Australia
| | - Susan Griffin
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Harin A Karunajeewa
- Population Health and Immunity, Walter and Eliza Hall Institute, Melbourne, Victoria, Australia
| | - Ivo Mueller
- Population Health and Immunity, Walter and Eliza Hall Institute, Melbourne, Victoria, Australia
- Barcelona Institute for Global Health (ISGLOBAL), Barcelona, Spain
| | - Stephen J Rogerson
- Department of Medicine (RMH), The University of Melbourne, Parkville, Victoria, Australia
| | - Peter M Siba
- Papua New Guinea Institute of Medical Research, Madang, Papua New Guinea
| | - Kenneth F Ilett
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
| | - Timothy M E Davis
- School of Medicine and Pharmacology, University of Western Australia, Crawley, Western Australia, Australia
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Corral MG, Leroux J, Stubbs KA, Mylne JS. Herbicidal properties of antimalarial drugs. Sci Rep 2017; 7:45871. [PMID: 28361906 PMCID: PMC5374466 DOI: 10.1038/srep45871] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 03/03/2017] [Indexed: 12/22/2022] Open
Abstract
The evolutionary relationship between plants and the malarial parasite Plasmodium falciparum is well established and underscored by the P. falciparum apicoplast, an essential chloroplast-like organelle. As a result of this relationship, studies have demonstrated that herbicides active against plants are also active against P. falciparum and thus could act as antimalarial drug leads. Here we show the converse is also true; many antimalarial compounds developed for human use are highly herbicidal. We found that human antimalarial drugs (e.g. sulfadiazine, sulfadoxine, pyrimethamine, cycloguanil) were lethal to the model plant Arabidopsis thaliana at similar concentrations to market herbicides glufosinate and glyphosate. Furthermore, the physicochemical properties of these herbicidal antimalarial compounds were similar to commercially used herbicides. The implications of this finding that many antimalarial compounds are herbicidal proffers two novel applications: (i) using the genetically tractable A. thaliana to reveal mode-of-action for understudied antimalarial drugs, and (ii) co-opting antimalarial compounds as a new source for much needed herbicide lead molecules.
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Affiliation(s)
- Maxime G Corral
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia.,The ARC Centre of Excellence in Plant Energy Biology, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - Julie Leroux
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia.,The ARC Centre of Excellence in Plant Energy Biology, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - Keith A Stubbs
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia
| | - Joshua S Mylne
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth 6009, Australia.,The ARC Centre of Excellence in Plant Energy Biology, 35 Stirling Highway, Crawley, Perth 6009, Australia
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35
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Rogerson SJ, Unger HW. Prevention and control of malaria in pregnancy - new threats, new opportunities? Expert Rev Anti Infect Ther 2016; 15:361-375. [PMID: 27973923 DOI: 10.1080/14787210.2017.1272411] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
INTRODUCTION Over 100 million women and their babies are at risk of malaria in pregnancy each year. Malaria prevention in pregnancy relies on long-lasting insecticidal nets (LLINs), and, in Africa, intermittent preventive treatment in pregnancy (IPTp). Increasing resistance of malaria parasites to sulfadoxine-pyrimethamine, the only drug endorsed for IPTp, and increasing mosquito resistance to pyrethroids used in LLINs, threaten the efficacy of these proven strategies, while operational challenges restrict their implementation in areas of great need. Areas Covered: This review summarizes strategies for malaria prevention in pregnancy (both currently used and those undergoing preclinical and clinical evaluation), primarily drawing on publications and study protocols from the last decade. Challenges associated with each strategy are discussed, including the particular problem of HIV and malaria in pregnancy, and areas of further research are highlighted. Expert Commentary: Alternative drugs for IPTp are needed. Dihydroartemisinin-piperaquine is particularly promising, but requires further evaluation, and might contribute to artemisinin resistance. Intermittent screening and treatment in pregnancy (ISTp) is an alternative to IPTp that could reduce unnecessary antenatal drug exposure and resistance risk, but it is not recommended with current, insensitive screening tests. Optimal strategies for areas of low or declining malaria transmission remain to be determined.
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Affiliation(s)
- Stephen J Rogerson
- a Department of Medicine at the Doherty Institute , University of Melbourne , Melbourne , Australia
| | - Holger W Unger
- a Department of Medicine at the Doherty Institute , University of Melbourne , Melbourne , Australia.,b Department of Obstetrics and Gynaecology , Royal Infirmary of Edinburgh , Edinburgh , UK
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36
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Habib S, Vaishya S, Gupta K. Translation in Organelles of Apicomplexan Parasites. Trends Parasitol 2016; 32:939-952. [DOI: 10.1016/j.pt.2016.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Revised: 07/19/2016] [Accepted: 07/25/2016] [Indexed: 01/27/2023]
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37
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Targeting Protein Translation in Organelles of the Apicomplexa. Trends Parasitol 2016; 32:953-965. [DOI: 10.1016/j.pt.2016.09.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 09/21/2016] [Accepted: 09/23/2016] [Indexed: 12/15/2022]
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38
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Mishra M, Mishra VK, Kashaw V, Iyer AK, Kashaw SK. Comprehensive review on various strategies for antimalarial drug discovery. Eur J Med Chem 2016; 125:1300-1320. [PMID: 27886547 DOI: 10.1016/j.ejmech.2016.11.025] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/07/2016] [Accepted: 11/11/2016] [Indexed: 01/14/2023]
Abstract
The resistance of malaria parasites to existing drugs carries on growing and progressively limiting our ability to manage this severe disease and finally lead to a massive global health burden. Till now, malaria control has relied upon the traditional quinoline, antifolate and artemisinin compounds. Very few new antimalarials were developed in the past 50 years. Among recent approaches, identification of novel chemotherapeutic targets, exploration of natural products with medicinal significance, covalent bitherapy having a dual mode of action into a single hybrid molecule and malaria vaccine development are explored heavily. The proper execution of these approaches and proper investment from international agencies will accelerate the discovery of drugs that provide new hope for the control or eventual eradication of this global infectious disease. This review explores various strategies for assessment and development of new antimalarial drugs. Current status and scientific value of previous approaches are systematically reviewed and new approaches provide a pragmatic forecast for future developments are introduced as well.
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Affiliation(s)
- Mitali Mishra
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India
| | - Vikash K Mishra
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India
| | - Varsha Kashaw
- SVN Institute of Pharmaceutical Sciences, SVN University, Sagar, MP, India
| | - Arun K Iyer
- Use-inspired Biomaterials & Integrated Nano Delivery (U-BiND) Systems Laboratory, Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA
| | - Sushil Kumar Kashaw
- Department of Pharmaceutical Sciences, Dr. Harisingh Gour University (A Central University), Sagar, MP, India; Use-inspired Biomaterials & Integrated Nano Delivery (U-BiND) Systems Laboratory, Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, USA.
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39
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Chakraborty A. Understanding the biology of the Plasmodium falciparum apicoplast; an excellent target for antimalarial drug development. Life Sci 2016; 158:104-10. [DOI: 10.1016/j.lfs.2016.06.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 11/29/2022]
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40
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Richards SN, Nash MN, Baker ES, Webster MW, Lehane AM, Shafik SH, Martin RE. Molecular Mechanisms for Drug Hypersensitivity Induced by the Malaria Parasite's Chloroquine Resistance Transporter. PLoS Pathog 2016; 12:e1005725. [PMID: 27441371 PMCID: PMC4956231 DOI: 10.1371/journal.ppat.1005725] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 06/03/2016] [Indexed: 01/23/2023] Open
Abstract
Mutations in the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) confer resistance to chloroquine (CQ) and related antimalarials by enabling the protein to transport these drugs away from their targets within the parasite’s digestive vacuole (DV). However, CQ resistance-conferring isoforms of PfCRT (PfCRTCQR) also render the parasite hypersensitive to a subset of structurally-diverse pharmacons. Moreover, mutations in PfCRTCQR that suppress the parasite’s hypersensitivity to these molecules simultaneously reinstate its sensitivity to CQ and related drugs. We sought to understand these phenomena by characterizing the functions of PfCRTCQR isoforms that cause the parasite to become hypersensitive to the antimalarial quinine or the antiviral amantadine. We achieved this by measuring the abilities of these proteins to transport CQ, quinine, and amantadine when expressed in Xenopus oocytes and complemented this work with assays that detect the drug transport activity of PfCRT in its native environment within the parasite. Here we describe two mechanistic explanations for PfCRT-induced drug hypersensitivity. First, we show that quinine, which normally accumulates inside the DV and therewithin exerts its antimalarial effect, binds extremely tightly to the substrate-binding site of certain isoforms of PfCRTCQR. By doing so it likely blocks the normal physiological function of the protein, which is essential for the parasite’s survival, and the drug thereby gains an additional killing effect. In the second scenario, we show that although amantadine also sequesters within the DV, the parasite’s hypersensitivity to this drug arises from the PfCRTCQR-mediated transport of amantadine from the DV into the cytosol, where it can better access its antimalarial target. In both cases, the mutations that suppress hypersensitivity also abrogate the ability of PfCRTCQR to transport CQ, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding clinically-relevant observations of inverse drug susceptibilities in the malaria parasite. In acquiring resistance to one drug, many pathogens and cancer cells become hypersensitive to other drugs. This phenomenon could be exploited to combat existing drug resistance and to delay the emergence of resistance to new drugs. However, much remains to be understood about the mechanisms that underlie drug hypersensitivity in otherwise drug-resistant microbes. Here, we describe two mechanisms by which the Plasmodium falciparum ‘chloroquine resistance transporter’ (PfCRT) causes the malaria parasite to become hypersensitive to structurally-diverse drugs. First, we show that an antimalarial drug that normally exerts its killing effect within the parasite’s digestive vacuole is also able to bind extremely tightly to certain forms of PfCRT. This activity will block the natural, essential function of the protein and thereby provide the drug with an additional killing effect. The second mechanism arises when a cytosolic-acting drug that normally sequesters within the digestive vacuole is leaked back into the cytosol via PfCRT. In both cases, mutations that suppress hypersensitivity also abrogate the ability of PfCRT to transport chloroquine, thus explaining why rescue from hypersensitivity restores the parasite’s sensitivity to this antimalarial. These insights provide a foundation for understanding and exploiting the hypersensitivity of chloroquine-resistant parasites to several of the current antimalarials.
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Affiliation(s)
- Sashika N. Richards
- Research School of Biology, Australian National University, Canberra, Australia
| | - Megan N. Nash
- Research School of Biology, Australian National University, Canberra, Australia
| | - Eileen S. Baker
- Research School of Biology, Australian National University, Canberra, Australia
| | - Michael W. Webster
- Research School of Biology, Australian National University, Canberra, Australia
| | - Adele M. Lehane
- Research School of Biology, Australian National University, Canberra, Australia
| | - Sarah H. Shafik
- Research School of Biology, Australian National University, Canberra, Australia
| | - Rowena E. Martin
- Research School of Biology, Australian National University, Canberra, Australia
- * E-mail:
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41
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Phong NC, Quang HH, Thanh NX, Trung TN, Dai B, Shanks GD, Chavchich M, Edstein MD. In Vivo Efficacy and Tolerability of Artesunate-Azithromycin for the Treatment of Falciparum Malaria in Vietnam. Am J Trop Med Hyg 2016; 95:164-7. [PMID: 27215294 DOI: 10.4269/ajtmh.16-0144] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/04/2016] [Indexed: 11/07/2022] Open
Abstract
Safe and effective antimalarial drugs are required for the treatment of pregnant women. We report a 3-day regimen of artesunate (4 mg/kg/day)-azithromycin (25 mg/kg/day) (ASAZ) to be efficacious (polymerase chain reaction-corrected cure rate of 96.7%) and well tolerated in the treatment of Plasmodium falciparum malaria in children (N = 11) and adults (N = 19), in Vietnam in 2010. In comparison, the cure rate for artesunate (4 mg/kg on day 0, 2 mg/kg on days 1-6) was 90.0% in children (N = 7) and adults (N = 23). Because azithromycin is considered safe in pregnancy, our findings provide further evidence that ASAZ should be evaluated for the treatment of pregnant women with malaria.
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Affiliation(s)
- Nguyen Chinh Phong
- Malaria Department, Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Huynh Hong Quang
- Malaria Department, Institute of Malariology, Parasitology and Entomology, Quy Nhon, Vietnam
| | - Nguyen Xuan Thanh
- Malaria Department, Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - Trieu Nguyen Trung
- Malaria Department, Institute of Malariology, Parasitology and Entomology, Quy Nhon, Vietnam
| | - Bui Dai
- Malaria Department, Military Institute of Preventive Medicine, Hanoi, Vietnam
| | - G Dennis Shanks
- Department of Drug Evaluation, Australian Army Malaria Institute, Brisbane, Australia
| | - Marina Chavchich
- Department of Drug Evaluation, Australian Army Malaria Institute, Brisbane, Australia
| | - Michael D Edstein
- Department of Drug Evaluation, Australian Army Malaria Institute, Brisbane, Australia.
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42
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Lemieux JE, Tran AD, Freimark L, Schaffner SF, Goethert H, Andersen KG, Bazner S, Li A, McGrath G, Sloan L, Vannier E, Milner D, Pritt B, Rosenberg E, Telford S, Bailey JA, Sabeti PC. A global map of genetic diversity in Babesia microti reveals strong population structure and identifies variants associated with clinical relapse. Nat Microbiol 2016; 1:16079. [PMID: 27572973 DOI: 10.1038/nmicrobiol.2016.79] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 04/28/2016] [Indexed: 11/09/2022]
Abstract
Human babesiosis caused by Babesia microti is an emerging tick-borne zoonosis of increasing importance due to its rising incidence and expanding geographic range(1). Infection with this organism, an intraerythrocytic parasite of the phylum Apicomplexa, causes a febrile syndrome similar to malaria(2). Relapsing disease is common among immunocompromised and asplenic individuals(3,4) and drug resistance has recently been reported(5). To investigate the origin and genetic diversity of this parasite, we sequenced the complete genomes of 42 B. microti samples from around the world, including deep coverage of clinical infections at endemic sites in the continental USA. Samples from the continental USA segregate into a Northeast lineage and a Midwest lineage, with subsequent divergence of subpopulations along geographic lines. We identify parasite variants that associate with relapsing disease, including amino acid substitutions in the atovaquone-binding regions of cytochrome b (cytb) and the azithromycin-binding region of ribosomal protein subunit L4 (rpl4). Our results shed light on the origin, diversity and evolution of B. microti, suggest possible mechanisms for clinical relapse, and create the foundation for further research on this emerging pathogen.
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Affiliation(s)
- Jacob E Lemieux
- The Broad Institute of MIT Division of Health Sciences and and MIT, Cambridge 02142, Massachusetts, USA.,Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Alice D Tran
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Lisa Freimark
- The Broad Institute of MIT Division of Health Sciences and and MIT, Cambridge 02142, Massachusetts, USA
| | - Stephen F Schaffner
- The Broad Institute of MIT Division of Health Sciences and and MIT, Cambridge 02142, Massachusetts, USA
| | - Heidi Goethert
- Tufts School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA
| | - Kristian G Andersen
- The Broad Institute of MIT Division of Health Sciences and and MIT, Cambridge 02142, Massachusetts, USA.,The Scripps Research Institute, La Jolla, California 92037, USA
| | - Suzane Bazner
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Amy Li
- Koch Institute for Integrative Cancer Research at MIT, Cambridge, Massachusetts 02142, USA
| | - Graham McGrath
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Lynne Sloan
- Department of Pathology, The Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Edouard Vannier
- Division of Geographic Medicine and Infectious Disease, Tufts Medical Center, Boston, Massachusetts 02111, USA
| | - Dan Milner
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA
| | - Bobbi Pritt
- Department of Pathology, The Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Eric Rosenberg
- Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Sam Telford
- Tufts School of Veterinary Medicine, North Grafton, Massachusetts 01536, USA
| | - Jeffrey A Bailey
- Program in Bioinformatics and Integrative Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.,Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
| | - Pardis C Sabeti
- The Broad Institute of MIT Division of Health Sciences and and MIT, Cambridge 02142, Massachusetts, USA.,Department of Evolutionary and Organismic Biology, MIT Division of Health Sciences and University, Cambridge, Massachusetts 02138, USA
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43
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Pasaje CFA, Cheung V, Kennedy K, Lim EE, Baell JB, Griffin MDW, Ralph SA. Selective inhibition of apicoplast tryptophanyl-tRNA synthetase causes delayed death in Plasmodium falciparum. Sci Rep 2016; 6:27531. [PMID: 27277538 PMCID: PMC4899734 DOI: 10.1038/srep27531] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 05/19/2016] [Indexed: 11/11/2022] Open
Abstract
The malaria parasite Plasmodium falciparum relies on efficient protein translation. An essential component of translation is the tryptophanyl-tRNA synthetase (TrpRS) that charges tRNAtrp. Here we characterise two isoforms of TrpRS in Plasmodium; one eukaryotic type localises to the cytosol and a bacterial type localises to the remnant plastid (apicoplast). We show that the apicoplast TrpRS aminoacylates bacterial tRNAtrp while the cytosolic TrpRS charges eukaryotic tRNAtrp. An inhibitor of bacterial TrpRSs, indolmycin, specifically inhibits aminoacylation by the apicoplast TrpRS in vitro, and inhibits ex vivo Plasmodium parasite growth, killing parasites with a delayed death effect characteristic of apicoplast inhibitors. Indolmycin treatment ablates apicoplast inheritance and is rescuable by addition of the apicoplast metabolite isopentenyl pyrophosphate (IPP). These data establish that inhibition of an apicoplast housekeeping enzyme leads to loss of the apicoplast and this is sufficient for delayed death. Apicoplast TrpRS is essential for protein translation and is a promising, specific antimalarial target.
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Affiliation(s)
- Charisse Flerida A Pasaje
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Vanessa Cheung
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Kit Kennedy
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Erin E Lim
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Jonathan B Baell
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 399 Royal Parade, Parkville, 3052 Victoria, Australia
| | - Michael D W Griffin
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Victoria 3010, Australia
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44
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Lawres LA, Garg A, Kumar V, Bruzual I, Forquer IP, Renard I, Virji AZ, Boulard P, Rodriguez EX, Allen AJ, Pou S, Wegmann KW, Winter RW, Nilsen A, Mao J, Preston DA, Belperron AA, Bockenstedt LK, Hinrichs DJ, Riscoe MK, Doggett JS, Ben Mamoun C. Radical cure of experimental babesiosis in immunodeficient mice using a combination of an endochin-like quinolone and atovaquone. J Exp Med 2016; 213:1307-18. [PMID: 27270894 PMCID: PMC4925016 DOI: 10.1084/jem.20151519] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 04/25/2016] [Indexed: 01/24/2023] Open
Abstract
Human babesiosis is a tick-borne multisystem disease caused by Babesia species of the apicomplexan phylum. Most clinical cases and fatalities of babesiosis are caused by Babesia microti Current treatment for human babesiosis consists of two drug combinations, atovaquone + azithromycin or quinine + clindamycin. These treatments are associated with adverse side effects and a significant rate of drug failure. Here, we provide evidence for radical cure of experimental babesiosis in immunodeficient mice using a combination of an endochin-like quinolone (ELQ) prodrug and atovaquone. In vivo efficacy studies in mice using ELQ-271, ELQ-316, and the ELQ-316 prodrug, ELQ-334, demonstrated excellent growth inhibitory activity against the parasite, with potency equal to that of orally administered atovaquone at 10 mg/kg. Analysis of recrudescent parasites after ELQ or atovaquone monotherapy identified genetic substitutions in the Qi or Qo sites, respectively, of the cytochrome bc1 complex. Impressively, a combination of ELQ-334 and atovaquone, at doses as low as 5.0 mg/kg each, resulted in complete clearance of the parasite with no recrudescence up to 122 d after discontinuation of therapy. These results will set the stage for future clinical evaluation of ELQ and atovaquone combination therapy for treatment of human babesiosis.
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Affiliation(s)
- Lauren A Lawres
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Aprajita Garg
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Vidya Kumar
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Igor Bruzual
- Veterans Affairs Medical Center, Portland, OR 97239
| | | | - Isaline Renard
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Azan Z Virji
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Pierre Boulard
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Eduardo X Rodriguez
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Alexander J Allen
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
| | - Sovitj Pou
- Veterans Affairs Medical Center, Portland, OR 97239
| | | | | | - Aaron Nilsen
- Veterans Affairs Medical Center, Portland, OR 97239
| | - Jialing Mao
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | | | - Alexia A Belperron
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | - Linda K Bockenstedt
- Department of Internal Medicine, Section of Rheumatology, Yale School of Medicine, New Haven, CT 06520
| | | | | | | | - Choukri Ben Mamoun
- Department of Internal Medicine, Section of Infectious Diseases, Yale School of Medicine, New Haven, CT 06520
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45
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Profiling the Essential Nature of Lipid Metabolism in Asexual Blood and Gametocyte Stages of Plasmodium falciparum. Cell Host Microbe 2016; 18:371-81. [PMID: 26355219 DOI: 10.1016/j.chom.2015.08.003] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 06/29/2015] [Accepted: 08/13/2015] [Indexed: 11/23/2022]
Abstract
During its life cycle, Plasmodium falciparum undergoes rapid proliferation fueled by de novo synthesis and acquisition of host cell lipids. Consistent with this essential role, Plasmodium lipid synthesis enzymes are emerging as potential drug targets. To explore their broader potential for therapeutic interventions, we assayed the global lipid landscape during P. falciparum sexual and asexual blood stage (ABS) development. Using liquid chromatography-mass spectrometry, we analyzed 304 lipids constituting 24 classes in ABS parasites, infected red blood cell (RBC)-derived microvesicles, gametocytes, and uninfected RBCs. Ten lipid classes were previously uncharacterized in P. falciparum, and 70%-75% of the lipid classes exhibited changes in abundance during ABS and gametocyte development. Utilizing compounds that target lipid metabolism, we affirmed the essentiality of major classes, including triacylglycerols. These studies highlight the interplay between host and parasite lipid metabolism and provide a comprehensive analysis of P. falciparum lipids with candidate pathways for drug discovery efforts.
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Vembar SS, Droll D, Scherf A. Translational regulation in blood stages of the malaria parasite Plasmodium spp.: systems-wide studies pave the way. WILEY INTERDISCIPLINARY REVIEWS-RNA 2016; 7:772-792. [PMID: 27230797 PMCID: PMC5111744 DOI: 10.1002/wrna.1365] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/21/2016] [Accepted: 04/26/2016] [Indexed: 11/10/2022]
Abstract
The malaria parasite Plasmodium spp. varies the expression profile of its genes depending on the host it resides in and its developmental stage. Virtually all messenger RNA (mRNA) is expressed in a monocistronic manner, with transcriptional activation regulated at the epigenetic level and by specialized transcription factors. Furthermore, recent systems-wide studies have identified distinct mechanisms of post-transcriptional and translational control at various points of the parasite lifecycle. Taken together, it is evident that 'just-in-time' transcription and translation strategies coexist and coordinate protein expression during Plasmodium development, some of which we review here. In particular, we discuss global and specific mechanisms that control protein translation in blood stages of the human malaria parasite Plasmodium falciparum, once a cytoplasmic mRNA has been generated, and its crosstalk with mRNA decay and storage. We also focus on the widespread translational delay observed during the 48-hour blood stage lifecycle of P. falciparum-for over 30% of transcribed genes, including virulence factors required to invade erythrocytes-and its regulation by cis-elements in the mRNA, RNA-processing enzymes and RNA-binding proteins; the first-characterized amongst these are the DNA- and RNA-binding Alba proteins. More generally, we conclude that translational regulation is an emerging research field in malaria parasites and propose that its elucidation will not only shed light on the complex developmental program of this parasite, but may also reveal mechanisms contributing to drug resistance and define new targets for malaria intervention strategies. WIREs RNA 2016, 7:772-792. doi: 10.1002/wrna.1365 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Shruthi Sridhar Vembar
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France.
| | - Dorothea Droll
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
| | - Artur Scherf
- Unité Biologie des Interactions Hôte-Parasite, Département de Parasites et Insectes Vecteurs, Institut Pasteur, Paris, France
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Rosenthal PJ. Azithromycin for Malaria? Am J Trop Med Hyg 2016; 95:2-4. [PMID: 27215296 PMCID: PMC4944689 DOI: 10.4269/ajtmh.16-0332] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 11/07/2022] Open
Affiliation(s)
- Philip J Rosenthal
- Department of Medicine, University of California, San Francisco, California
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Gaillard T, Dormoi J, Madamet M, Pradines B. Macrolides and associated antibiotics based on similar mechanism of action like lincosamides in malaria. Malar J 2016; 15:85. [PMID: 26873741 PMCID: PMC4752764 DOI: 10.1186/s12936-016-1114-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 01/20/2016] [Indexed: 01/10/2023] Open
Abstract
Malaria, a parasite vector-borne disease, is one of the biggest health threats in tropical regions, despite the availability of malaria chemoprophylaxis. The emergence and rapid extension of Plasmodium falciparum resistance to various anti-malarial drugs has gradually limited the potential malaria therapeutics available to clinicians. In this context, macrolides and associated antibiotics based on similar mechanism of action like lincosamides constitute an interesting alternative in the treatment of malaria. These molecules, whose action spectrum is similar to that of tetracyclines, are typically administered to children and pregnant women. Recent studies have examined the effects of azithromycin and the lincosamide clindamycin, on isolates from different continents. Azithromycin and clindamycin are effective and well tolerated in the treatment of uncomplicated malaria in combination with quinine. This literature review assesses the roles of macrolides and lincosamides in the prophylaxis and treatment of malaria.
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Affiliation(s)
- Tiphaine Gaillard
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Fédération des Laboratoires, Hôpital d'Instruction des Armées Saint Anne, Toulon, France.
| | - Jérôme Dormoi
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France.
| | - Marylin Madamet
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Equipe Résidente de Recherche en Infectiologie Tropicale, Institut de Recherche Biomédicale des Armées, Hôpital d'Instruction des Armées, Marseille, France. .,Centre National de Référence du Paludisme, Marseille, France.
| | - Bruno Pradines
- Unité de Parasitologie, Département d'Infectiologie de Terrain, Institut de Recherche Biomédicale des Armées, Marseille, France. .,Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Aix Marseille Université, UM 63, CNRS 7278, IRD 198, Inserm, 1095, Marseille, France. .,Unité de Parasitologie et d'Entomologie, Département des Maladies Infectieuses, Institut de Recherche Biomédicale des Armées, Brétigny sur Orge, France. .,Centre National de Référence du Paludisme, Marseille, France.
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Makgatho M, Maimela E, Mbajiorgu F. Ketolide agents HMR 3004 and HMR 3647 (telithromycin) inhibit the growth of Plasmodium falciparum in vitro. Afr Health Sci 2015; 15:1271-6. [PMID: 26958030 DOI: 10.4314/ahs.v15i4.28] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Malaria is on the increase due to emergence of parasite drug resistance and there is thus an urgent need for the development of new antiparasitic drugs effective at low concentrations. Ketolides antibiotics are used for treatment of various ailments and are relevant candidates to establish antiparasitic activity. OBJECTIVES The present study investigates the activity of ketolide compounds HMR 3004 and HMR 3647 (telithromycin) (0.025-12.5 µM) for activity against chloroquine-sensitive and resistant strains of Plasmodium falciparum in vitro. METHODS The antiplasmodial activity of the two ketolide agents were determined using microscopic and colorimetric [lactate dehydrogenase assay] procedures. RESULTS Both HMR 3004 and HMR 3647 caused a dose-dependent inhibition of growth of both parasite strains with IC50 values 3 and 15 nM, respectively. Suppression of parasite growth was evident after 8 hours of exposure to both agents at 12.5 µM with total parasite clearance achieved at 40 hours. CONCLUSION The results indicate lack of cross-resistance between the ketolide compounds and chloroquine, implying presence of a drug target different from that of chloroquine. The particular drug target has still to be investigated but the stage-specific results indicate that it is expressed in all parasite growth phases. These observations demonstrate the anti-malarial potential of the ketolide antimicrobial agents.
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Cravo P, Napolitano H, Culleton R. How genomics is contributing to the fight against artemisinin-resistant malaria parasites. Acta Trop 2015; 148:1-7. [PMID: 25910626 DOI: 10.1016/j.actatropica.2015.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 04/06/2015] [Accepted: 04/11/2015] [Indexed: 11/30/2022]
Abstract
Plasmodium falciparum, the malignant malaria parasite, has developed resistance to artemisinin, the most important and widely used antimalarial drug at present. Currently confined to Southeast Asia, the spread of resistant parasites to Africa would constitute a public health catastrophe. In this review we highlight the recent contributions of genomics to our understanding how the parasite develops resistance to artemisinin and its derivatives, and how resistant parasites may be monitored and tracked in real-time, using molecular approaches.
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Affiliation(s)
- Pedro Cravo
- Laboratory of Genomics and Biotechnology (GenoBio), IPTSP, Universidade Federal de Goiás, Goiânia 74605050, GO, Brazil; PPSTMA, Centro Universitário de Anápolis (UniEVANGÉLICA), Anápolis 75083515, GO, Brazil; Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon 1349-008, Portugal.
| | - Hamilton Napolitano
- PPSTMA, Centro Universitário de Anápolis (UniEVANGÉLICA), Anápolis 75083515, GO, Brazil; Ciências Exatas e Tecnológicas, Universidade Estadual de Goiás. 459, 75001970 Anápolis, GO, Brazil
| | - Richard Culleton
- Malaria Unit, Department of Pathology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 8528523, Japan
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