1
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Blanken SL, Barry A, Lanke K, Guelbeogo M, Ouedraogo A, Soulama I, Coulibaly SA, Teelen K, Graumans W, Dumont E, Stone W, Ramjith J, Marti M, Andrade CM, Drakeley C, Collins K, Tiono A, Bousema T. Plasmodium falciparum gametocyte production correlates with genetic markers of parasite replication but is not influenced by experimental exposure to mosquito biting. EBioMedicine 2024; 105:105190. [PMID: 38901148 PMCID: PMC11239461 DOI: 10.1016/j.ebiom.2024.105190] [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: 11/17/2023] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND Plasmodium blood-stage parasites balance asexual multiplication with gametocyte development. Few studies link these dynamics with parasite genetic markers in vivo; even fewer in longitudinally monitored infections. Environmental influences on gametocyte formation, such as mosquito exposure, may influence the parasite's investment in gametocyte production. METHODS We investigated gametocyte production and asexual multiplication in two Plasmodium falciparum infected populations; a controlled human malaria infection (CHMI) study and a 28-day observational study in naturally infected individuals in Burkina Faso with controlled mosquito exposure. We measured gene transcript levels previously related to gametocyte formation (ap2-g, surfin1.2, surfin13.1, gexp-2) or inhibition of asexual multiplication (sir2a) and compared transcript levels to ring-stage parasite and mature gametocyte densities. FINDINGS Three of the five markers (ap2-g, surfin1.2, surfin13.1) predicted peak gametocytaemia in the CHMI study. An increase in all five markers in natural infections was associated with an increase in mature gametocytes 14 days later; the effect of sir2a on future gametocytes was strongest (fold change = 1.65, IQR = 1.22-2.24, P = 0.004). Mosquito exposure was not associated with markers of gametocyte formation (ap2-g P = 0.277; sir2a P = 0.499) or carriage of mature gametocytes (P = 0.379). INTERPRETATION All five parasite genetic markers predicted gametocyte formation over a single cycle of gametocyte formation and maturation in vivo; sir2a and ap2-g were most closely associated with gametocyte growth dynamics. We observed no evidence to support the hypothesis that exposure to Anopheles mosquito bites stimulates gametocyte formation. FUNDING This work was funded by the Bill & Melinda Gates Foundation (INDIE OPP1173572), the European Research Council fellowship (ERC-CoG 864180) and UKRI Medical Research Council (MR/T016272/1) and Wellcome Center (218676/Z/19/Z).
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Affiliation(s)
- Sara Lynn Blanken
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Aissata Barry
- Groupe de Recherche Action en Santé (GRAS), Ouagadougou, Burkina Faso
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Moussa Guelbeogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Sam Aboubacar Coulibaly
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Karina Teelen
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Wouter Graumans
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Elin Dumont
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Will Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Jordache Ramjith
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Matthias Marti
- Wellcome Centre for Integrative Parasitology, Institute of Infection and Immunity, University of Glasgow, Glasgow, Scotland, UK
| | - Carolina M Andrade
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Chris Drakeley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Katharine Collins
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands
| | - Alfred Tiono
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Nijmegen, the Netherlands; Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
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2
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Goodwin J, Kajubi R, Wang K, Li F, Wade M, Orukan F, Huang L, Whalen M, Aweeka FT, Mwebaza N, Parikh S. Persistent and multiclonal malaria parasite dynamics despite extended artemether-lumefantrine treatment in children. Nat Commun 2024; 15:3817. [PMID: 38714692 PMCID: PMC11076639 DOI: 10.1038/s41467-024-48210-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 04/24/2024] [Indexed: 05/10/2024] Open
Abstract
Standard diagnostics used in longitudinal antimalarial studies are unable to characterize the complexity of submicroscopic parasite dynamics, particularly in high transmission settings. We use molecular markers and amplicon sequencing to characterize post-treatment stage-specific malaria parasite dynamics during a 42 day randomized trial of 3- versus 5 day artemether-lumefantrine in 303 children with and without HIV (ClinicalTrials.gov number NCT03453840). The prevalence of parasite-derived 18S rRNA is >70% in children throughout follow-up, and the ring-stage marker SBP1 is detectable in over 15% of children on day 14 despite effective treatment. We find that the extended regimen significantly lowers the risk of recurrent ring-stage parasitemia compared to the standard 3 day regimen, and that higher day 7 lumefantrine concentrations decrease the probability of ring-stage parasites in the early post-treatment period. Longitudinal amplicon sequencing reveals remarkably dynamic patterns of multiclonal infections that include new and persistent clones in both the early post-treatment and later time periods. Our data indicate that post-treatment parasite dynamics are highly complex despite efficacious therapy, findings that will inform strategies to optimize regimens in the face of emerging partial artemisinin resistance in Africa.
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Affiliation(s)
- Justin Goodwin
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
- Yale School of Medicine, New Haven, CT, USA
| | - Richard Kajubi
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Kaicheng Wang
- Yale Center for Analytical Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Fangyong Li
- Yale Center for Analytical Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Martina Wade
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Francis Orukan
- Infectious Disease Research Collaboration, Kampala, Uganda
| | - Liusheng Huang
- University of California, San Francisco, San Francisco, CA, USA
| | - Meghan Whalen
- University of California, San Francisco, San Francisco, CA, USA
| | | | - Norah Mwebaza
- Infectious Disease Research Collaboration, Kampala, Uganda
- Department of Pharmacology and Therapeutics, Makerere University College of Health Sciences, Kampala, Uganda
| | - Sunil Parikh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA.
- Yale School of Medicine, New Haven, CT, USA.
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3
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Abstract
Malaria symptoms are caused by the development of the parasites within the blood of an infected host. Bulk RNA sequencing (RNA-seq) of infected blood can reveal interactions between parasites and the host immune system during an infection, but because multiple developmental stages with distinct transcriptional profiles are concurrently present in infected blood, it is necessary to correct such analyses for differences in cell composition among samples. Gene expression deconvolution is a statistical approach that has been developed for inferring the cell composition of complex tissues characterized by bulk RNA-seq using gene expression profiles from reference cell types. Here, we describe the evaluation of a species-agnostic reference data set that can be used for efficient and accurate gene expression deconvolution of bulk RNA-seq data generated from any Plasmodium species and for correct gene expression analyses for biases caused by differences in stage composition among samples. IMPORTANCE Differences in cell type proportions among samples can introduce artifacts in gene expression analyses and mask genuine differences in gene regulation. Gene expression deconvolution allows estimation of the proportion of each cell type present in one sample directly from bulk RNA sequencing data, but this approach requires a reference data set with the signature profile of each cell type. Here, we evaluate the suitability of a rodent malaria parasite gene expression data set for estimating the proportions of each parasite developmental stage present in bulk RNA sequencing data generated from blood-stage infections with the human parasites Plasmodium falciparum and Plasmodium vivax. These analyses provide a species-agnostic approach for reliably estimating stage proportions in infected human blood and correcting subsequent gene expression analyses for these variations.
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4
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Gadalla AAH, Siciliano G, Farid R, Alano P, Ranford-Cartwright L, McCarthy JS, Thompson J, Babiker HA. Real-time PCR assays for detection and quantification of early P. falciparum gametocyte stages. Sci Rep 2021; 11:19118. [PMID: 34580326 PMCID: PMC8476600 DOI: 10.1038/s41598-021-97456-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/25/2021] [Indexed: 11/11/2022] Open
Abstract
The use of quantitative qRT-PCR assays for detection and quantification of late gametocyte stages has revealed the high transmission capacity of the human malaria parasite, Plasmodium falciparum. To understand how the parasite adjusts its transmission in response to in-host environmental conditions including antimalarials requires simultaneous quantification of early and late gametocytes. Here, we describe qRT-PCR assays that specifically detect and quantify early-stage P. falciparum gametocytes. The assays are based on expression of known early and late gametocyte genes and were developed using purified stage II and stage V gametocytes and tested in natural and controlled human infections. Genes pfpeg4 and pfg27 are specifically expressed at significant levels in early gametocytes with a limit of quantification of 190 and 390 gametocytes/mL, respectively. In infected volunteers, transcripts of pfpeg4 and pfg27 were detected shortly after the onset of blood stage infection. In natural infections, both early (pfpeg4/pfg27) and late gametocyte transcripts (pfs25) were detected in 71.2% of individuals, only early gametocyte transcripts in 12.6%, and only late gametocyte transcripts in 15.2%. The pfpeg4/pfg27 qRT-PCR assays are sensitive and specific for quantification of circulating sexually committed ring stages/early gametocytes and can be used to increase our understanding of epidemiological processes that modulate P. falciparum transmission.
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Affiliation(s)
- Amal A H Gadalla
- College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman.,Division of Population Medicine, School of Medicine, College of Biomedical Sciences, Cardiff University, Cardiff, UK
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Ryan Farid
- QIMR Berghofer Medical Research Institute and University of Queensland, Brisbane, Australia
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Lisa Ranford-Cartwright
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - James S McCarthy
- QIMR Berghofer Medical Research Institute and University of Queensland, Brisbane, Australia
| | - Joanne Thompson
- Institute of Immunology and Infection Research, School of Biological Sciences, Ashworth Laboratories, University of Edinburgh, Edinburgh, UK
| | - Hamza A Babiker
- College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman.
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5
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Barry A, Bradley J, Stone W, Guelbeogo MW, Lanke K, Ouedraogo A, Soulama I, Nébié I, Serme SS, Grignard L, Patterson C, Wu L, Briggs JJ, Janson O, Awandu SS, Ouedraogo M, Tarama CW, Kargougou D, Zongo S, Sirima SB, Marti M, Drakeley C, Tiono AB, Bousema T. Higher gametocyte production and mosquito infectivity in chronic compared to incident Plasmodium falciparum infections. Nat Commun 2021; 12:2443. [PMID: 33903595 PMCID: PMC8076179 DOI: 10.1038/s41467-021-22573-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 03/09/2021] [Indexed: 11/09/2022] Open
Abstract
Plasmodium falciparum gametocyte kinetics and infectivity may differ between chronic and incident infections. In the current study, we assess parasite kinetics and infectivity to mosquitoes among children (aged 5-10 years) from Burkina Faso with (a) incident infections following parasite clearance (n = 48) and (b) chronic asymptomatic infections (n = 60). In the incident infection cohort, 92% (44/48) of children develop symptoms within 35 days, compared to 23% (14/60) in the chronic cohort. All individuals with chronic infection carried gametocytes or developed them during follow-up, whereas only 35% (17/48) in the incident cohort produce gametocytes before becoming symptomatic and receiving treatment. Parasite multiplication rate (PMR) and the relative abundance of ap2-g and gexp-5 transcripts are positively associated with gametocyte production. Antibody responses are higher and PMR lower in chronic infections. The presence of symptoms and sexual stage immune responses are associated with reductions in gametocyte infectivity to mosquitoes. We observe that most incident infections require treatment before the density of mature gametocytes is sufficient to infect mosquitoes. In contrast, chronic, asymptomatic infections represent a significant source of mosquito infections. Our observations support the notion that malaria transmission reduction may be expedited by enhanced case management, involving both symptom-screening and infection detection.
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Affiliation(s)
- Aissata Barry
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
- Radboud Institute for Health Sciences and Radboud Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - John Bradley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Will Stone
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Moussa W Guelbeogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Kjerstin Lanke
- Radboud Institute for Health Sciences and Radboud Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Alphonse Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Issiaka Soulama
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Issa Nébié
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Samuel S Serme
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Lynn Grignard
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Catriona Patterson
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Lindsey Wu
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Jessica J Briggs
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Owen Janson
- Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Shehu S Awandu
- Radboud Institute for Health Sciences and Radboud Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Mireille Ouedraogo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Casimire W Tarama
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Désiré Kargougou
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Soumanaba Zongo
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Matthias Marti
- Wellcome Centre for Integrative Parasitology, University of Glasgow, Glasgow, UK
| | - Chris Drakeley
- MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme (CNRFP), Ouagadougou 01, Burkina Faso
| | - Teun Bousema
- Radboud Institute for Health Sciences and Radboud Center for Infectious Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands.
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6
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Stiffler DM, Oyieko J, Kifude CM, Rockabrand DM, Luckhart S, Stewart VA. HIV-1 Infection Is Associated With Increased Prevalence and Abundance of Plasmodium falciparum Gametocyte-Specific Transcripts in Asymptomatic Adults in Western Kenya. Front Cell Infect Microbiol 2021; 10:600106. [PMID: 33614525 PMCID: PMC7892447 DOI: 10.3389/fcimb.2020.600106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/16/2020] [Indexed: 01/05/2023] Open
Abstract
As morbidity and mortality due to malaria continue to decline, the identification of individuals with a high likelihood of transmitting malaria is needed to further reduce the prevalence of malaria. In areas of holoendemic malaria transmission, asymptomatically infected adults may be infected with transmissible gametocytes. The impact of HIV-1 on gametocyte carriage is unknown, but co-infection may lead to an increase in gametocytemia. In this study, a panel of qPCR assays was used to quantify gametocyte stage-specific transcripts present in dried blood spots obtained from asymptomatic adults seeking voluntary HIV testing in Kombewa, Kenya. A total of 1,116 Plasmodium-specific 18S-positive samples were tested and 20.5% of these individuals had detectable gametocyte-specific transcripts. Individuals also infected with HIV-1 were 1.82 times more likely to be gametocyte positive (P<0.0001) and had significantly higher gametocyte copy numbers when compared to HIV-negative individuals. Additionally, HIV-1 positivity was associated with higher gametocyte prevalence in men and increased gametocyte carriage with age. Overall, these data suggest that HIV-positive individuals may have an increased risk of transmitting malaria parasites in regions with endemic malaria transmission and therefore should be at a higher priority for treatment with gametocidal antimalarial drugs.
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Affiliation(s)
- Deborah M Stiffler
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Janet Oyieko
- Basic Science Laboratory, US Army Medical Research Directorate-Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - Carolyne M Kifude
- Basic Science Laboratory, US Army Medical Research Directorate-Africa/Kenya Medical Research Institute, Kisumu, Kenya
| | - David M Rockabrand
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology and Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - V Ann Stewart
- Department of Preventive Medicine and Biostatistics, Division of Tropical Public Health, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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7
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van der Puije W, Wang CW, Sudharson S, Hempel C, Olsen RW, Dalgaard N, Ofori MF, Hviid L, Kurtzhals JAL, Staalsoe T. In vitro selection for adhesion of Plasmodium falciparum-infected erythrocytes to ABO antigens does not affect PfEMP1 and RIFIN expression. Sci Rep 2020; 10:12871. [PMID: 32732983 PMCID: PMC7393120 DOI: 10.1038/s41598-020-69666-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 07/09/2020] [Indexed: 11/09/2022] Open
Abstract
Plasmodium falciparum causes the most severe form of malaria in humans. The adhesion of the infected erythrocytes (IEs) to endothelial receptors (sequestration) and to uninfected erythrocytes (rosetting) are considered major elements in the pathogenesis of the disease. Both sequestration and rosetting appear to involve particular members of several IE variant surface antigens (VSAs) as ligands, interacting with multiple vascular host receptors, including the ABO blood group antigens. In this study, we subjected genetically distinct P. falciparum parasites to in vitro selection for increased IE adhesion to ABO antigens in the absence of potentially confounding receptors. The selection resulted in IEs that adhered stronger to pure ABO antigens, to erythrocytes, and to various human cell lines than their unselected counterparts. However, selection did not result in marked qualitative changes in transcript levels of the genes encoding the best-described VSA families, PfEMP1 and RIFIN. Rather, overall transcription of both gene families tended to decline following selection. Furthermore, selection-induced increases in the adhesion to ABO occurred in the absence of marked changes in immune IgG recognition of IE surface antigens, generally assumed to target mainly VSAs. Our study sheds new light on our understanding of the processes and molecules involved in IE sequestration and rosetting.
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Affiliation(s)
- William van der Puije
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana.,Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet, Ole Maaløes Vej, 7602, 2200, Copenhagen, Denmark
| | - Christian W Wang
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Srinidhi Sudharson
- Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet, Ole Maaløes Vej, 7602, 2200, Copenhagen, Denmark
| | - Casper Hempel
- Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet, Ole Maaløes Vej, 7602, 2200, Copenhagen, Denmark
| | - Rebecca W Olsen
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nanna Dalgaard
- Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael F Ofori
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon, Ghana
| | - Lars Hviid
- Department of Infectious Diseases, Rigshospitalet, Copenhagen, Denmark.,Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen A L Kurtzhals
- Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet, Ole Maaløes Vej, 7602, 2200, Copenhagen, Denmark.,Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Trine Staalsoe
- Centre for Medical Parasitology, Department of Clinical Microbiology, Rigshospitalet, Ole Maaløes Vej, 7602, 2200, Copenhagen, Denmark. .,Centre for Medical Parasitology, Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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8
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Alkema M, Reuling IJ, de Jong GM, Lanke K, Coffeng LE, van Gemert GJ, van de Vegte-Bolmer M, de Mast Q, van Crevel R, Ivinson K, Ockenhouse CF, McCarthy JS, Sauerwein R, Collins KA, Bousema T. A randomized clinical trial to compare P. falciparum gametocytaemia and infectivity following blood-stage or mosquito bite induced controlled malaria infection. J Infect Dis 2020; 224:1257-1265. [PMID: 32239171 PMCID: PMC8514191 DOI: 10.1093/infdis/jiaa157] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 03/31/2020] [Indexed: 11/21/2022] Open
Abstract
Background For malaria elimination efforts, it is important to better understand parasite transmission to mosquitoes and develop models for early-clinical evaluation of transmission-blocking interventions. Methods In a randomized open-label trial, 24 participants were infected by bites from Plasmodium falciparum 3D7-infected mosquitoes (mosquito bite [MB]; n = 12) or by induced blood-stage malaria (IBSM) with the same parasite line (n = 12). After subcurative piperaquine treatment, asexual parasite and gametocytes kinetics were assessed, and mosquito feeding experiments were performed. Results Study procedures were well tolerated. The median peak gametocyte density was 1304/mL (interquartile range, 308–1607/mL) after IBSM, compared with 14/mL (10–64/mL) after MB inoculation (P < .001), despite similar peak asexual parasite densities (P = .48). Peak gametocyte density was correlated with preceding pfap2-g transcripts, indicative of gametocyte commitment (ρ = 0.62; P = .002). Direct feeding assays resulted in mosquito infections from 9 of 12 participants after IBSM versus 0 of 12 after MB inoculation (P < .001). Conclusions We observed a striking effect of inoculation method on gametocyte production, suggesting higher gametocyte commitment after IBSM. Our direct comparison of MB and IBSM establishes the controlled human malaria infection transmission model, using intravenous administration of P. falciparum–infected erythrocytes as a model for early-clinical evaluation of interventions that aim to interrupt malaria transmission. Clinical Trial Registration NCT03454048
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Affiliation(s)
- Manon Alkema
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Isaie J Reuling
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Gerdie M de Jong
- Department of Medical Microbiology and Infectious Diseases, University Medical Center Rotterdam, CA Rotterdam, The Netherlands
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Luc E Coffeng
- Department of Public Health, University Medical Center Rotterdam, CA Rotterdam, The Netherlands
| | - Geert-Jan van Gemert
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | | | - Quirijn de Mast
- Department of Internal Medicine, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Reinout van Crevel
- Department of Internal Medicine, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Karen Ivinson
- PATH Malaria Vaccine Initiative, Washington, DC, United States
| | | | - James S McCarthy
- Clinical Tropical Medicine Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Katharine A Collins
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud university medical center, HB Nijmegen, The Netherlands
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9
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Bhowmick K, Tehlan A, Sunita, Sudhakar R, Kaur I, Sijwali PS, Krishnamachari A, Dhar SK. Plasmodium falciparum GCN5 acetyltransferase follows a novel proteolytic processing pathway that is essential for its function. J Cell Sci 2020; 133:jcs.236489. [PMID: 31862795 DOI: 10.1242/jcs.236489] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
The pathogenesis of human malarial parasite Plasmodium falciparum is interlinked with its timely control of gene expression during its complex life cycle. In this organism, gene expression is partially controlled through epigenetic mechanisms, the regulation of which is, hence, of paramount importance to the parasite. The P. falciparum (Pf)-GCN5 histone acetyltransferase (HAT), an essential enzyme, acetylates histone 3 and regulates global gene expression in the parasite. Here, we show the existence of a novel proteolytic processing for PfGCN5 that is crucial for its activity in vivo We find that a cysteine protease-like enzyme is required for the processing of PfGCN5 protein. Immunofluorescence and immuno-electron microscopy analysis suggest that the processing event occurs in the vicinity of the digestive vacuole of the parasite following its trafficking through the classical ER-Golgi secretory pathway, before it subsequently reaches the nucleus. Furthermore, blocking of PfGCN5 processing leads to the concomitant reduction of its occupancy at the gene promoters and a reduced H3K9 acetylation level at these promoters, highlighting the important correlation between the processing event and PfGCN5 activity. Altogether, our study reveals a unique processing event for a nuclear protein PfGCN5 with unforeseen role of a food vacuolar cysteine protease. This leads to a possibility of the development of new antimalarials against these targets.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Krishanu Bhowmick
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ankita Tehlan
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Sunita
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Renu Sudhakar
- Centre for Cellular and Molecular Biology, Hyderabad, Telengana 500007, India
| | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Puran Singh Sijwali
- Centre for Cellular and Molecular Biology, Hyderabad, Telengana 500007, India
| | | | - Suman Kumar Dhar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
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10
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Plasmodium falciparum sexual differentiation in malaria patients is associated with host factors and GDV1-dependent genes. Nat Commun 2019; 10:2140. [PMID: 31086187 PMCID: PMC6514009 DOI: 10.1038/s41467-019-10172-6] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 04/12/2019] [Indexed: 01/06/2023] Open
Abstract
Plasmodium sexual differentiation is required for malaria transmission, yet much remains unknown about its regulation. Here, we quantify early gametocyte-committed ring (gc-ring) stage, P. falciparum parasites in 260 uncomplicated malaria patient blood samples 10 days before maturation to transmissible stage V gametocytes using a gametocyte conversion assay (GCA). Seventy six percent of the samples have gc-rings, but the ratio of gametocyte to asexual-committed rings (GCR) varies widely (0–78%). GCR correlates positively with parasitemia and is negatively influenced by fever, not hematocrit, age or leukocyte counts. Higher expression levels of GDV1-dependent genes, ap2-g, msrp1 and gexp5, as well as a gdv1 allele encoding H217 are associated with high GCR, while high plasma lysophosphatidylcholine levels are associated with low GCR in the second study year. The results provide a view of sexual differentiation in the field and suggest key regulatory roles for clinical factors and gdv1 in gametocytogenesis in vivo. Here, the authors quantify early gametocyte-committed ring (gc-ring) stage Plasmodium falciparum parasites in 260 malaria patients 10 days before maturation to transmissible stage V gametocytes, and show that the ratio of circulating gc-rings is positively correlated with parasitemia and negatively correlated with body temperature.
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11
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DSM265 at 400 Milligrams Clears Asexual Stage Parasites but Not Mature Gametocytes from the Blood of Healthy Subjects Experimentally Infected with Plasmodium falciparum. Antimicrob Agents Chemother 2019; 63:AAC.01837-18. [PMID: 30858218 PMCID: PMC6437518 DOI: 10.1128/aac.01837-18] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 01/25/2019] [Indexed: 12/19/2022] Open
Abstract
DSM265 is a novel antimalarial drug in clinical development that acts as a selective inhibitor of Plasmodium dihydroorotate dehydrogenase. In a previous phase 1b study, a single 150-mg dose of DSM265 showed partial efficacy against experimentally induced blood-stage Plasmodium falciparum malaria (IBSM). DSM265 is a novel antimalarial drug in clinical development that acts as a selective inhibitor of Plasmodium dihydroorotate dehydrogenase. In a previous phase 1b study, a single 150-mg dose of DSM265 showed partial efficacy against experimentally induced blood-stage Plasmodium falciparum malaria (IBSM). Pharmacokinetic/pharmacodynamic modeling predicted a human efficacious dose of 340 mg. The primary objectives of the current study were to determine the safety and efficacy of a single oral 400-mg dose of DSM265 against P. falciparum in the IBSM model. Eight healthy participants were inoculated intravenously with 2,800 parasites and treated with DSM265 7 days later. Unexpectedly, one participant did not develop parasitemia during the study. All other participants developed parasitemia, with the complete clearance of asexual parasites occurring following DSM265 treatment. All seven subjects also became gametocytemic. The secondary objectives were to investigate the gametocytocidal and transmission-blocking activity of a second 400-mg dose of DSM265, which was administered 23 days after inoculation. Gametocytes were not cleared by the second dose of DSM265, and transmission-blocking activity could not be determined due to low gametocyte densities. Three DSM265-related adverse events occurred, including a cutaneous rash in one subject on the day of the second DSM265 dose. The results obtained in this study support the prediction of the efficacious dose of DSM265 and provide further evidence that DSM265 is generally safe and well tolerated. In addition, this study confirms preclinical data indicating that DSM265 permits the development and maturation of gametocytes and does not clear mature circulating gametocytes. (This study has been registered at ClinicalTrials.gov under identifier NCT02573857.)
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12
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Tadesse FG, Meerstein-Kessel L, Gonçalves BP, Drakeley C, Ranford-Cartwright L, Bousema T. Gametocyte Sex Ratio: The Key to Understanding Plasmodium falciparum Transmission? Trends Parasitol 2018; 35:226-238. [PMID: 30594415 PMCID: PMC6396025 DOI: 10.1016/j.pt.2018.12.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 11/30/2018] [Accepted: 12/03/2018] [Indexed: 11/25/2022]
Abstract
A mosquito needs to ingest at least one male and one female gametocyte to become infected with malaria. The sex of Plasmodium falciparum gametocytes can be determined microscopically but recent transcriptomics studies paved the way for the development of molecular methods that allow sex-ratio assessments at much lower gametocyte densities. These sex-specific gametocyte diagnostics were recently used to examine gametocyte dynamics in controlled and natural infections as well as the impact of different antimalarial drugs. It is currently unclear to what extent sex-specific gametocyte diagnostics obviate the need for mosquito feeding assays to formally assess transmission potential. Here, we review recent and historic assessments of gametocyte sex ratio in relation to host and parasite characteristics, treatment, and transmission potential. Recent RNA sequencing studies have uncovered a number of P. falciparum gametocyte sex-specific targets and provided new insights in gametocyte biology. After decades when gametocyte sex-ratio research was restricted to nonhuman malarias or in vitro experiments, molecular tools for assessing gametocyte sex ratio are now increasingly available for use in natural P. falciparum infections. Evidence that gametocyte sex ratio is influenced by total gametocyte density and antimalarial treatment, and improves predictions of transmission potential, highlight the relevance of understanding the gametocyte sex ratio during natural infections. The finding that the most widely used P. falciparum gametocyte marker Pfs25 is expressed predominantly by female gametocytes and has non-negligible levels of background expression in asexual parasites necessitates a re-evaluation of existing gametocyte data.
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Affiliation(s)
- Fitsum G Tadesse
- Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands; Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia; Institute of Biotechnology, Addis Ababa University, Addis Ababa, Ethiopia; These authors contributed equally
| | - Lisette Meerstein-Kessel
- Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands; These authors contributed equally
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK
| | - Lisa Ranford-Cartwright
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Teun Bousema
- Radboud Institute for Health Sciences, Radboud University Medical Centre, Nijmegen, The Netherlands; Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, UK.
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13
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Tarr SJ, Díaz-Ingelmo O, Stewart LB, Hocking SE, Murray L, Duffy CW, Otto TD, Chappell L, Rayner JC, Awandare GA, Conway DJ. Schizont transcriptome variation among clinical isolates and laboratory-adapted clones of the malaria parasite Plasmodium falciparum. BMC Genomics 2018; 19:894. [PMID: 30526479 PMCID: PMC6288915 DOI: 10.1186/s12864-018-5257-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 11/16/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Malaria parasites are genetically polymorphic and phenotypically plastic. In studying transcriptome variation among parasites from different infections, it is challenging to overcome potentially confounding technical and biological variation between samples. We investigate variation in the major human parasite Plasmodium falciparum, generating RNA-seq data on multiple independent replicate sample preparations of merozoite-containing intra-erythrocytic schizonts from a panel of clinical isolates and from long-term laboratory-adapted clones, with a goal of robustly identifying differentially expressed genes. RESULTS Analysis of biological sample replicates shows that increased numbers improve the true discovery rate of differentially expressed genes, and that six independent replicates of each parasite line allowed identification of most differences that could be detected with larger numbers. For highly expressed genes, focusing on the top quartile at schizont stages, there was more power to detect differences. Comparing cultured clinical isolates and laboratory-adapted clones, genes more highly expressed in the laboratory-adapted clones include those encoding an AP2 transcription factor (PF3D7_0420300), a ubiquitin-binding protein and two putative methyl transferases. In contrast, higher expression in clinical isolates was seen for the merozoite surface protein gene dblmsp2, proposed to be a marker of schizonts forming merozoites committed to sexual differentiation. Variable expression was extremely strongly, but not exclusively, associated with genes known to be targeted by Heterochromatin Protein 1. Clinical isolates show variable expression of several known merozoite invasion ligands, as well as other genes for which new RT-qPCR assays validate the quantitation and allow characterisation in samples with more limited material. Expression levels of these genes vary among schizont preparations of different clinical isolates in the first ex vivo cycle in patient erythrocytes, but mean levels are similar to those in continuously cultured clinical isolates. CONCLUSIONS Analysis of multiple biological sample replicates greatly improves identification of genes variably expressed between different cultured parasite lines. Clinical isolates recently established in culture show differences from long-term adapted clones in transcript levels of particular genes, and are suitable for analyses requiring biological replicates to understand parasite phenotypes and variable expression likely to be relevant in nature.
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Affiliation(s)
- Sarah J Tarr
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK.
| | - Ofelia Díaz-Ingelmo
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Lindsay B Stewart
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Suzanne E Hocking
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Lee Murray
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Craig W Duffy
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK
| | - Thomas D Otto
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Scotland, UK.,Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Lia Chappell
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | | | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens, Department of Biochemistry, Cell and Molecular Biology, University of Ghana, Legon, Ghana
| | - David J Conway
- Pathogen Molecular Biology Department, London School of Hygiene and Tropical Medicine, London, UK.
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14
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Dinko B, Ansah F, Agyare-Kwabi C, Tagboto S, Amoah LE, Urban BC, Sutherland CJ, Awandare GA, Williamson KC, Binka FN, Deitsch KW. Gametocyte Development and Carriage in Ghanaian Individuals with Uncomplicated Plasmodium falciparum Malaria. Am J Trop Med Hyg 2018; 99:57-64. [PMID: 29692310 PMCID: PMC6085798 DOI: 10.4269/ajtmh.18-0077] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 02/23/2018] [Indexed: 01/29/2023] Open
Abstract
Plasmodium falciparum gametocytes develop over 9-12 days while sequestered in deep tissues. On emergence into the bloodstream, they circulate for varied amounts of time during which certain host factors might influence their further development. We aimed to evaluate the potential association of patient clinical parameters with gametocyte development and carriage via in vivo methods. Seventy-two patients were enrolled from three hospitals in the Volta region of Ghana in 2016. Clinical parameters were documented for all patients, and gametocyte prevalence by microscopy was estimated at 12.5%. By measuring RNA transcripts representing two distinct gametocyte developmental stages using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), we obtained a more precise estimate of gametocyte carriage while also inferring gametocyte maturation. Fifty-three percent of the study participants harbored parasites expressing transcripts of the immature gametocyte-specific gene (PF3D7_1477700), whereas 36% harbored PF3D7_1438800 RNA-positive parasites, which is enriched in mid and mature gametocytes, suggesting the presence of more immature stages. Linear logistic regression showed that patients older than 5 years but less than 16 years were more likely to carry gametocytes expressing both PF3D7_1477700 and PF3D7_1438800 compared with younger participants, and gametocytemia was more likely in mildly anemic individuals compared with those with severe/moderate anemia. These data provide further evidence that a greater number of malaria patients harbor gametocytes than typically estimated by microscopy and suggest a possible association between age, fever, anemia, and gametocytemia.
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Affiliation(s)
- Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Felix Ansah
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Comfort Agyare-Kwabi
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
| | - Senyo Tagboto
- Department of Internal Medicine, School of Medicine, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Linda Eva Amoah
- Department of Immunology, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana
| | - Britta C. Urban
- Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Colin J. Sutherland
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gordon A. Awandare
- West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Kim C. Williamson
- Microbiology and Immunology Department, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Fred N. Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Volta Region, Ghana
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York
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15
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Lee HJ, Georgiadou A, Walther M, Nwakanma D, Stewart LB, Levin M, Otto TD, Conway DJ, Coin LJ, Cunnington AJ. Integrated pathogen load and dual transcriptome analysis of systemic host-pathogen interactions in severe malaria. Sci Transl Med 2018; 10:eaar3619. [PMID: 29950443 PMCID: PMC6326353 DOI: 10.1126/scitranslmed.aar3619] [Citation(s) in RCA: 77] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 01/31/2018] [Accepted: 06/08/2018] [Indexed: 12/13/2022]
Abstract
The pathogenesis of infectious diseases depends on the interaction of host and pathogen. In Plasmodium falciparum malaria, host and parasite processes can be assessed by dual RNA sequencing of blood from infected patients. We performed dual transcriptome analyses on samples from 46 malaria-infected Gambian children to reveal mechanisms driving the systemic pathophysiology of severe malaria. Integrating these transcriptomic data with estimates of parasite load and detailed clinical information allowed consideration of potentially confounding effects due to differing leukocyte proportions in blood, parasite developmental stage, and whole-body pathogen load. We report hundreds of human and parasite genes differentially expressed between severe and uncomplicated malaria, with distinct profiles associated with coma, hyperlactatemia, and thrombocytopenia. High expression of neutrophil granule-related genes was consistently associated with all severe malaria phenotypes. We observed severity-associated variation in the expression of parasite genes, which determine cytoadhesion to vascular endothelium, rigidity of infected erythrocytes, and parasite growth rate. Up to 99% of human differential gene expression in severe malaria was driven by differences in parasite load, whereas parasite gene expression showed little association with parasite load. Coexpression analyses revealed interactions between human and P. falciparum, with prominent co-regulation of translation genes in severe malaria between host and parasite. Multivariate analyses suggested that increased expression of granulopoiesis and interferon-γ-related genes, together with inadequate suppression of type 1 interferon signaling, best explained severity of infection. These findings provide a framework for understanding the contributions of host and parasite to the pathogenesis of severe malaria and identifying new treatments.
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Affiliation(s)
- Hyun Jae Lee
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Michael Walther
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O. Box 273, Fajara, The Gambia
| | - Davis Nwakanma
- Medical Research Council Unit The Gambia at London School of Hygiene and Tropical Medicine, P.O. Box 273, Fajara, The Gambia
| | - Lindsay B Stewart
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Michael Levin
- Section of Paediatrics, Imperial College, London W2 1PG, UK
| | - Thomas D Otto
- Wellcome Trust Sanger Centre, Hinxton, Cambridge CB10 1SA, UK
| | - David J Conway
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Lachlan J Coin
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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16
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Lee HJ, Georgiadou A, Otto TD, Levin M, Coin LJ, Conway DJ, Cunnington AJ. Transcriptomic Studies of Malaria: a Paradigm for Investigation of Systemic Host-Pathogen Interactions. Microbiol Mol Biol Rev 2018; 82:e00071-17. [PMID: 29695497 PMCID: PMC5968457 DOI: 10.1128/mmbr.00071-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Transcriptomics, the analysis of genome-wide RNA expression, is a common approach to investigate host and pathogen processes in infectious diseases. Technical and bioinformatic advances have permitted increasingly thorough analyses of the association of RNA expression with fundamental biology, immunity, pathogenesis, diagnosis, and prognosis. Transcriptomic approaches can now be used to realize a previously unattainable goal, the simultaneous study of RNA expression in host and pathogen, in order to better understand their interactions. This exciting prospect is not without challenges, especially as focus moves from interactions in vitro under tightly controlled conditions to tissue- and systems-level interactions in animal models and natural and experimental infections in humans. Here we review the contribution of transcriptomic studies to the understanding of malaria, a parasitic disease which has exerted a major influence on human evolution and continues to cause a huge global burden of disease. We consider malaria a paradigm for the transcriptomic assessment of systemic host-pathogen interactions in humans, because much of the direct host-pathogen interaction occurs within the blood, a readily sampled compartment of the body. We illustrate lessons learned from transcriptomic studies of malaria and how these lessons may guide studies of host-pathogen interactions in other infectious diseases. We propose that the potential of transcriptomic studies to improve the understanding of malaria as a disease remains partly untapped because of limitations in study design rather than as a consequence of technological constraints. Further advances will require the integration of transcriptomic data with analytical approaches from other scientific disciplines, including epidemiology and mathematical modeling.
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Affiliation(s)
- Hyun Jae Lee
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | | | - Thomas D Otto
- Centre of Immunobiology, University of Glasgow, Glasgow, United Kingdom
| | - Michael Levin
- Section of Paediatrics, Imperial College, London, United Kingdom
| | - Lachlan J Coin
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Australia
| | - David J Conway
- Department of Pathogen Molecular Biology, London School of Hygiene and Tropical Medicine, London, United Kingdom
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17
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Obaldia N, Meibalan E, Sa JM, Ma S, Clark MA, Mejia P, Moraes Barros RR, Otero W, Ferreira MU, Mitchell JR, Milner DA, Huttenhower C, Wirth DF, Duraisingh MT, Wellems TE, Marti M. Bone Marrow Is a Major Parasite Reservoir in Plasmodium vivax Infection. mBio 2018; 9:e00625-18. [PMID: 29739900 PMCID: PMC5941073 DOI: 10.1128/mbio.00625-18] [Citation(s) in RCA: 127] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 04/11/2018] [Indexed: 11/25/2022] Open
Abstract
Plasmodium vivax causes heavy burdens of disease across malarious regions worldwide. Mature P. vivax asexual and transmissive gametocyte stages occur in the blood circulation, and it is often assumed that accumulation/sequestration in tissues is not an important phase in their development. Here, we present a systematic study of P. vivax stage distributions in infected tissues of nonhuman primate (NHP) malaria models as well as in blood from human infections. In a comparative analysis of the transcriptomes of P. vivax and Plasmodium falciparum blood-stage parasites, we found a conserved cascade of stage-specific gene expression despite the greatly different gametocyte maturity times of these two species. Using this knowledge, we validated a set of conserved asexual- and gametocyte-stage markers both by quantitative real-time PCR and by antibody assays of peripheral blood samples from infected patients and NHP (Aotus sp.). Histological analyses of P. vivax parasites in organs of 13 infected NHP (Aotus and Saimiri species) demonstrated a major fraction of immature gametocytes in the parenchyma of the bone marrow, while asexual schizont forms were enriched to a somewhat lesser extent in this region of the bone marrow as well as in sinusoids of the liver. These findings suggest that the bone marrow is an important reservoir for gametocyte development and proliferation of malaria parasites.IMPORTANCEPlasmodium vivax malaria continues to cause major public health burdens worldwide. Yet, significant knowledge gaps in the basic biology and epidemiology of P. vivax malaria remain, largely due to limited available tools for research and diagnostics. Here, we present a systematic examination of tissue sequestration during P. vivax infection. Studies of nonhuman primates and malaria patients revealed enrichment of developing sexual stages (gametocytes) and mature replicative stages (schizonts) in the bone marrow and liver, relative to those present in peripheral blood. Identification of the bone marrow as a major P. vivax tissue reservoir has important implications for parasite diagnosis and treatment.
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Affiliation(s)
- Nicanor Obaldia
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
- Tropical Medicine Research, Panama City, Panama
- Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama City, Panama
| | - Elamaran Meibalan
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
- Center for Excellence in Vascular Biology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Juliana M Sa
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Siyuan Ma
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Martha A Clark
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Pedro Mejia
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Roberto R Moraes Barros
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - William Otero
- Tropical Medicine Research, Panama City, Panama
- Instituto Conmemorativo Gorgas de Estudios de la Salud, Panama City, Panama
| | - Marcelo U Ferreira
- Department of Parasitology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - James R Mitchell
- Department of Genetics and Complex Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Danny A Milner
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
| | - Thomas E Wellems
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland, USA
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA
- Wellcome Centre for Molecular Parasitology, University of Glasgow, Glasgow, United Kingdom
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18
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Collins KA, Wang CY, Adams M, Mitchell H, Rampton M, Elliott S, Reuling IJ, Bousema T, Sauerwein R, Chalon S, Möhrle JJ, McCarthy JS. A controlled human malaria infection model enabling evaluation of transmission-blocking interventions. J Clin Invest 2018; 128:1551-1562. [PMID: 29389671 PMCID: PMC5873858 DOI: 10.1172/jci98012] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/30/2018] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND. Drugs and vaccines that can interrupt the transmission of Plasmodium falciparum will be important for malaria control and elimination. However, models for early clinical evaluation of candidate transmission-blocking interventions are currently unavailable. Here, we describe a new model for evaluating malaria transmission from humans to Anopheles mosquitoes using controlled human malaria infection (CHMI). METHODS. Seventeen healthy malaria-naive volunteers underwent CHMI by intravenous inoculation of P. falciparum–infected erythrocytes to initiate blood-stage infection. Seven to eight days after inoculation, participants received piperaquine (480 mg) to attenuate asexual parasite replication while allowing gametocytes to develop and mature. Primary end points were development of gametocytemia, the transmissibility of gametocytes from humans to mosquitoes, and the safety and tolerability of the CHMI transmission model. To investigate in vivo gametocytocidal drug activity in this model, participants were either given an experimental antimalarial, artefenomel (500 mg), or a known gametocytocidal drug, primaquine (15 mg), or remained untreated during the period of gametocyte carriage. RESULTS. Male and female gametocytes were detected in all participants, and transmission to mosquitoes was achieved from 8 of 11 (73%) participants evaluated. Compared with results in untreated controls (n = 7), primaquine (15 mg, n = 5) significantly reduced gametocyte burden (P = 0.01), while artefenomel (500 mg, n = 4) had no effect. Adverse events (AEs) were mostly mild or moderate. Three AEs were assessed as severe — fatigue, elevated alanine aminotransferase, and elevated aspartate aminotransferase — and were attributed to malaria infection. Transaminase elevations were transient, asymptomatic, and resolved without intervention. CONCLUSION. We report the safe and reproducible induction of P. falciparum gametocytes in healthy malaria-naive volunteers at densities infectious to mosquitoes, thereby demonstrating the potential for evaluating transmission-blocking interventions in this model. TRIAL REGISTRATION. ClinicalTrials.gov NCT02431637 and NCT02431650. FUNDING. Bill & Melinda Gates Foundation.
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Affiliation(s)
| | - Claire Yt Wang
- Queensland Paediatric Infectious Diseases (QPID) Laboratory, Centre for Children's Health Research, Brisbane, Queensland, Australia
| | - Matthew Adams
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Hayley Mitchell
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Melanie Rampton
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | | | - Isaie J Reuling
- Radboud Institute for Health Science, Radboud University Medical Center, Nijmegen, Netherlands
| | - Teun Bousema
- Radboud Institute for Health Science, Radboud University Medical Center, Nijmegen, Netherlands
| | - Robert Sauerwein
- Radboud Institute for Health Science, Radboud University Medical Center, Nijmegen, Netherlands
| | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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19
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The Plasmodium falciparum transcriptome in severe malaria reveals altered expression of genes involved in important processes including surface antigen-encoding var genes. PLoS Biol 2018; 16:e2004328. [PMID: 29529020 PMCID: PMC5864071 DOI: 10.1371/journal.pbio.2004328] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 03/22/2018] [Accepted: 02/16/2018] [Indexed: 01/13/2023] Open
Abstract
Within the human host, the malaria parasite Plasmodium falciparum is exposed to multiple selection pressures. The host environment changes dramatically in severe malaria, but the extent to which the parasite responds to-or is selected by-this environment remains unclear. From previous studies, the parasites that cause severe malaria appear to increase expression of a restricted but poorly defined subset of the PfEMP1 variant, surface antigens. PfEMP1s are major targets of protective immunity. Here, we used RNA sequencing (RNAseq) to analyse gene expression in 44 parasite isolates that caused severe and uncomplicated malaria in Papuan patients. The transcriptomes of 19 parasite isolates associated with severe malaria indicated that these parasites had decreased glycolysis without activation of compensatory pathways; altered chromatin structure and probably transcriptional regulation through decreased histone methylation; reduced surface expression of PfEMP1; and down-regulated expression of multiple chaperone proteins. Our RNAseq also identified novel associations between disease severity and PfEMP1 transcripts, domains, and smaller sequence segments and also confirmed all previously reported associations between expressed PfEMP1 sequences and severe disease. These findings will inform efforts to identify vaccine targets for severe malaria and also indicate how parasites adapt to-or are selected by-the host environment in severe malaria.
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20
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Mahanta A, Ganguli P, Barah P, Sarkar RR, Sarmah N, Phukan S, Bora M, Baruah S. Integrative Approaches to Understand the Mastery in Manipulation of Host Cytokine Networks by Protozoan Parasites with Emphasis on Plasmodium and Leishmania Species. Front Immunol 2018. [PMID: 29527208 PMCID: PMC5829655 DOI: 10.3389/fimmu.2018.00296] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Diseases by protozoan pathogens pose a significant public health concern, particularly in tropical and subtropical countries, where these are responsible for significant morbidity and mortality. Protozoan pathogens tend to establish chronic infections underscoring their competence at subversion of host immune processes, an important component of disease pathogenesis and of their virulence. Modulation of cytokine and chemokine levels, their crosstalks and downstream signaling pathways, and thereby influencing recruitment and activation of immune cells is crucial to immune evasion and subversion. Many protozoans are now known to secrete effector molecules that actively modulate host immune transcriptome and bring about alterations in host epigenome to alter cytokine levels and signaling. The complexity of multi-dimensional events during interaction of hosts and protozoan parasites ranges from microscopic molecular levels to macroscopic ecological and epidemiological levels that includes disrupting metabolic pathways, cell cycle (Toxoplasma and Theileria sp.), respiratory burst, and antigen presentation (Leishmania spp.) to manipulation of signaling hubs. This requires an integrative systems biology approach to combine the knowledge from all these levels to identify the complex mechanisms of protozoan evolution via immune escape during host-parasite coevolution. Considering the diversity of protozoan parasites, in this review, we have focused on Leishmania and Plasmodium infections. Along with the biological understanding, we further elucidate the current efforts in generating, integrating, and modeling of multi-dimensional data to explain the modulation of cytokine networks by these two protozoan parasites to achieve their persistence in host via immune escape during host-parasite coevolution.
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Affiliation(s)
- Anusree Mahanta
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India.,Institute of Stem Cell Biology and Regenerative Medicine, Bengaluru, India
| | - Piyali Ganguli
- Chemical Engineering and Process Development, CSIR- National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-NCL Campus, Pune, India
| | - Pankaj Barah
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Ram Rup Sarkar
- Chemical Engineering and Process Development, CSIR- National Chemical Laboratory, Pune, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR-NCL Campus, Pune, India
| | - Neelanjana Sarmah
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Saurav Phukan
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Mayuri Bora
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
| | - Shashi Baruah
- Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur, India
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21
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Meerstein-Kessel L, van der Lee R, Stone W, Lanke K, Baker DA, Alano P, Silvestrini F, Janse CJ, Khan SM, van de Vegte-Bolmer M, Graumans W, Siebelink-Stoter R, Kooij TWA, Marti M, Drakeley C, Campo JJ, van Dam TJP, Sauerwein R, Bousema T, Huynen MA. Probabilistic data integration identifies reliable gametocyte-specific proteins and transcripts in malaria parasites. Sci Rep 2018; 8:410. [PMID: 29323249 PMCID: PMC5765010 DOI: 10.1038/s41598-017-18840-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 12/15/2017] [Indexed: 12/02/2022] Open
Abstract
Plasmodium gametocytes are the sexual forms of the malaria parasite essential for transmission to mosquitoes. To better understand how gametocytes differ from asexual blood-stage parasites, we performed a systematic analysis of available 'omics data for P. falciparum and other Plasmodium species. 18 transcriptomic and proteomic data sets were evaluated for the presence of curated "gold standards" of 41 gametocyte-specific versus 46 non-gametocyte genes and integrated using Bayesian probabilities, resulting in gametocyte-specificity scores for all P. falciparum genes. To illustrate the utility of the gametocyte score, we explored newly predicted gametocyte-specific genes as potential biomarkers of gametocyte carriage and exposure. We analyzed the humoral immune response in field samples against 30 novel gametocyte-specific antigens and found five antigens to be differentially recognized by gametocyte carriers as compared to malaria-infected individuals without detectable gametocytes. We also validated the gametocyte-specificity of 15 identified gametocyte transcripts on culture material and samples from naturally infected individuals, resulting in eight transcripts that were >1000-fold higher expressed in gametocytes compared to asexual parasites and whose transcript abundance allowed gametocyte detection in naturally infected individuals. Our integrated genome-wide gametocyte-specificity scores provide a comprehensive resource to identify targets and monitor P. falciparum gametocytemia.
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Affiliation(s)
- Lisette Meerstein-Kessel
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Robin van der Lee
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
- Centre for Molecular Medicine and Therapeutics, Department of Medical Genetics, BC Children's Hospital Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Will Stone
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - David A Baker
- Department of Pathogen Molecular Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Pietro Alano
- Dipartimento Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | | | - Chris J Janse
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Shahid M Khan
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Wouter Graumans
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Rianne Siebelink-Stoter
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Taco W A Kooij
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Matthias Marti
- Wellcome Trust Center for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Chris Drakeley
- Department of Immunology and Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Teunis J P van Dam
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
- Theoretical Biology and Bioinformatics, Department of Biology, Utrecht University, Utrecht, The Netherlands
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Teun Bousema
- Department of Medical Microbiology, Radboud university medical center, Nijmegen, The Netherlands
| | - Martijn A Huynen
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands.
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22
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Differential Roles for Inner Membrane Complex Proteins across Toxoplasma gondii and Sarcocystis neurona Development. mSphere 2017; 2:mSphere00409-17. [PMID: 29062899 PMCID: PMC5646244 DOI: 10.1128/msphere.00409-17] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Accepted: 09/29/2017] [Indexed: 12/30/2022] Open
Abstract
The inner membrane complex (IMC) is a defining feature of apicomplexan parasites key to both their motility and unique cell division. To provide further insights into the IMC, we analyzed the dynamics and functions of representative alveolin domain-containing IMC proteins across developmental stages. Our work shows universal but distinct roles for IMC1, -3, and -7 during Toxoplasma asexual division but more specialized functions for these proteins during gametogenesis. In addition, we find that IMC15 is involved in daughter formation in both Toxoplasma and Sarcocystis tachyzoites, bradyzoites, and sporozoites. IMC14 and IMC15 function in limiting the number of Toxoplasma offspring per division. Furthermore, IMC7, -12, and -14, which are recruited in the G1 cell cycle stage, are required for stress resistance of extracellular tachyzoites. Thus, although the roles of the different IMC proteins appear to overlap, stage- and development-specific behaviors indicate that their functions are uniquely tailored to each life stage requirement. The inner membrane complex (IMC) of apicomplexan parasites contains a network of intermediate filament-like proteins. The 14 alveolin domain-containing IMC proteins in Toxoplasma gondii fall into different groups defined by their distinct spatiotemporal dynamics during the internal budding process of tachyzoites. Here, we analyzed representatives of different IMC protein groups across all stages of the Toxoplasma life cycle and during Sarcocystis neurona asexual development. We found that across asexually dividing Toxoplasma stages, IMC7 is present exclusively in the mother’s cytoskeleton, whereas IMC1 and IMC3 are both present in mother and daughter cytoskeletons (IMC3 is strongly enriched in daughter buds). In developing macro- and microgametocytes, IMC1 and -3 are absent, whereas IMC7 is lost in early microgametocytes but retained in macrogametocytes until late in their development. We found no roles for IMC proteins during meiosis and sporoblast formation. However, we observed that IMC1 and IMC3, but not IMC7, are present in sporozoites. Although the spatiotemporal pattern of IMC15 and IMC3 suggests orthologous functions in Sarcocystis, IMC7 may have functionally diverged in Sarcocystis merozoites. To functionally characterize IMC proteins, we knocked out IMC7, -12, -14, and -15 in Toxoplasma. IMC14 and -15 appear to be involved in switching between endodyogeny and endopolygeny. In addition, IMC7, -12, and -14, which are all recruited to the cytoskeleton outside cytokinesis, are critical for the structural integrity of extracellular tachyzoites. Altogether, stage- and development-specific roles for IMC proteins can be discerned, suggesting different niches for each IMC protein across the entire life cycle. IMPORTANCE The inner membrane complex (IMC) is a defining feature of apicomplexan parasites key to both their motility and unique cell division. To provide further insights into the IMC, we analyzed the dynamics and functions of representative alveolin domain-containing IMC proteins across developmental stages. Our work shows universal but distinct roles for IMC1, -3, and -7 during Toxoplasma asexual division but more specialized functions for these proteins during gametogenesis. In addition, we find that IMC15 is involved in daughter formation in both Toxoplasma and Sarcocystis. IMC14 and IMC15 function in limiting the number of Toxoplasma offspring per division. Furthermore, IMC7, -12, and -14, which are recruited in the G1 cell cycle stage, are required for stress resistance of extracellular tachyzoites. Thus, although the roles of the different IMC proteins appear to overlap, stage- and development-specific behaviors indicate that their functions are uniquely tailored to each life stage requirement.
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23
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Gebru T, Lalremruata A, Kremsner PG, Mordmüller B, Held J. Life-span of in vitro differentiated Plasmodium falciparum gametocytes. Malar J 2017; 16:330. [PMID: 28800735 PMCID: PMC5553604 DOI: 10.1186/s12936-017-1986-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 08/07/2017] [Indexed: 11/18/2022] Open
Abstract
Background The sexual stages (gametocytes) of Plasmodium falciparum do not directly contribute to the pathology of malaria but are essential for transmission of the parasite from the human host to the mosquito. Mature gametocytes circulate in infected human blood for several days and their circulation time has been modelled mathematically from data of previous in vivo studies. This is the first time that longevity of gametocytes is studied experimentally in vitro. Methods The in vitro longevity of P. falciparum gametocytes of 1 clinical isolate and 2 laboratory strains was assessed by three different methods: microscopy, flow cytometry and reverse transcription quantitative real-time PCR (RT-qPCR). Additionally, the rate of gametocytogenesis of the used P. falciparum strains was compared. Results The maximum in vitro lifespan of P. falciparum gametocytes reached almost 2 months (49 days by flow cytometry, 46 days by microscopy, and at least 52 days by RT-qPCR) from the starting day of gametocyte culture to death of last parasite in the tested strains with an average 50% survival rate of 6.5, 2.6 and 3.5 days, respectively. Peak gametocytaemia was observed on average 19 days after initiation of gametocyte culture followed by a steady decline due to natural decay of the parasites. The rate of gametocytogenesis was highest in the NF54 strain. Conclusions Plasmodium falciparum mature gametocytes can survive up to 16–32 days (at least 14 days for mature male gametocytes) in vitro in absence of the influence of host factors. This confirms experimentally a previous modelling estimate that used molecular tools for gametocyte detection in treated patients. The survival time might reflect the time the parasite can be transmitted to the mosquito after clearance of asexual parasites. These results underline the importance of efficient transmission blocking agents in the fight against malaria. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1986-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tamirat Gebru
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany.,Department of Medical Laboratory Sciences, College of Medical and Health Sciences, Haramaya University, Harar, Ethiopia
| | - Albert Lalremruata
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany.,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany. .,German Centre for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany.
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24
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Tadesse FG, Lanke K, Nebie I, Schildkraut JA, Gonçalves BP, Tiono AB, Sauerwein R, Drakeley C, Bousema T, Rijpma SR. Molecular Markers for Sensitive Detection of Plasmodium falciparum Asexual Stage Parasites and their Application in a Malaria Clinical Trial. Am J Trop Med Hyg 2017; 97:188-198. [PMID: 28719294 PMCID: PMC5508903 DOI: 10.4269/ajtmh.16-0893] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Plasmodium falciparum parasite life stages respond differently to antimalarial drugs. Sensitive stage-specific molecular assays may help to examine parasite dynamics at microscopically detectable and submicroscopic parasite densities in epidemiological and clinical studies. In this study, we compared the performance of skeleton-binding protein 1 (SBP1), ring-infected erythrocyte surface antigen, Hyp8, ring-exported protein 1 (REX1), and PHISTb mRNA for detecting ring-stage trophozoite-specific transcripts using quantitative reverse transcriptase polymerase chain reaction. Markers were tested on tightly synchronized in vitro parasites and clinical trial samples alongside established markers of parasite density (18S DNA and rRNA) and gametocyte density (Pfs25 mRNA). SBP1 was the most sensitive marker but showed low-level expression in mature gametocytes. Novel markers REX1 and PHISTb showed lower sensitivity but higher specificity for ring-stage trophozoites. Using in vivo clinical trial samples from gametocyte-negative patients, we observed evidence of persisting trophozoite transcripts for at least 14 days postinitiation of treatment. It is currently not clear if these transcripts represent viable parasites that may have implications for clinical treatment outcome or transmission potential.
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Affiliation(s)
- Fitsum G Tadesse
- Armauer Hansen Research Institute (AHRI), Addis Ababa, Ethiopia.,Medical Biotechnology Unit, Institute of Biotechnology, Addis Ababa University, Addis Ababa, Ethiopia.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Issa Nebie
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou,Burkina Faso
| | - Jodie A Schildkraut
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Alfred B Tiono
- Department of Biomedical Sciences, Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou,Burkina Faso
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Sanna R Rijpma
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
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25
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Taylor BJ, Lanke K, Banman SL, Morlais I, Morin MJ, Bousema T, Rijpma SR, Yanow SK. A Direct from Blood Reverse Transcriptase Polymerase Chain Reaction Assay for Monitoring Falciparum Malaria Parasite Transmission in Elimination Settings. Am J Trop Med Hyg 2017; 97:533-543. [PMID: 28722583 DOI: 10.4269/ajtmh.17-0039] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
We describe a novel one-step reverse transcriptase real-time PCR (direct RT-PCR) for Plasmodium falciparum malaria parasites that amplifies RNA targets directly from blood. We developed the assay to identify gametocyte-specific transcripts in parasites from patient blood samples, as a means of monitoring malaria parasite transmission in field settings. To perform the test, blood is added directly to a master mix in PCR tubes and analyzed by real-time PCR. The limit of detection of the assay on both conventional and portable real-time PCR instruments was 100 parasites/mL for 18S rRNA, and 1,000 parasites/mL for asexual (PFE0065W) and gametocyte (PF14_0367, PFGEXP5) mRNA targets. The usefulness of this assay in field studies was explored in samples from individuals living in a high-transmission region in Cameroon. The sensitivity and specificity of the assay compared with a standard two-step RT-PCR was 100% for 18S rRNA on both conventional and portable instruments. For PF14_0367, the sensitivity and specificity were 85.7% and 70.0%, respectively, on the conventional instrument and 78.6% and 90%, respectively, on the portable instrument. The concordance for assays run on the two instruments was 100% for 18S rRNA, and 79.2% for PF14_0367, with most discrepancies resulting from samples with low transcript levels. The results show asexual and sexual stage RNA targets can be detected directly from blood samples in a simple one-step test on a field-friendly instrument. This assay may be useful for monitoring malaria parasite transmission potential in elimination settings, where sensitive diagnostics are needed to evaluate the progress of malaria eradication initiatives.
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Affiliation(s)
- Brian J Taylor
- School of Public Health, Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, Nijmegen, The Netherlands
| | - Shanna L Banman
- School of Public Health, Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada
| | - Isabelle Morlais
- Institut de Recherche pour le Développement, Université de Montpellier (UMR) MIVEGEC, Montpellier Cedex, France.,Laboratoire de Recherche sur le Paludisme, Organisation de Coordination pour la lutte contre les Endémies en Afrique centrale, Yaoundé, Cameroon
| | | | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, Nijmegen, The Netherlands
| | - Sanna R Rijpma
- Department of Medical Microbiology, Radboud University Medical Centre, Geert Grooteplein 26-28, Nijmegen, The Netherlands
| | - Stephanie K Yanow
- Department of Medical Microbiology and Immunology, Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada.,School of Public Health, Katz Group Centre, University of Alberta, Edmonton, Alberta, Canada
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26
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Affiliation(s)
- Robert E. Sinden
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
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27
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Hanron AE, Billman ZP, Seilie AM, Olsen TM, Fishbaugher M, Chang M, Rueckle T, Andenmatten N, Greenhouse B, Arinaitwe E, Rek J, Das S, Domingo GJ, Shipman K, Kappe SH, Kublin JG, Murphy SC. Multiplex, DNase-free one-step reverse transcription PCR for Plasmodium 18S rRNA and spliced gametocyte-specific mRNAs. Malar J 2017; 16:208. [PMID: 28526032 PMCID: PMC5438523 DOI: 10.1186/s12936-017-1863-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 05/13/2017] [Indexed: 01/01/2023] Open
Abstract
Background Plasmodium gametocytes are sexual stages transmitted to female Anopheles mosquitoes. While Plasmodium parasites can be differentiated microscopically on Giemsa-stained blood smears, molecular methods are increasingly used because of their increased sensitivity. Molecular detection of gametocytes requires methods that discriminate between asexual and sexual stage parasites. Commonly tested gametocyte-specific mRNAs are pfs25 and pfs230 detected by reverse transcription polymerase chain reaction (RT-PCR). However, detection of these unspliced mRNA targets requires preceding DNase treatment of nucleic acids to eliminate co-purified genomic DNA. If gametocyte-specific, spliced mRNAs could be identified, DNase treatment could be eliminated and one-step multiplexed molecular methods utilized. Results Expression data was used to identify highly-expressed mRNAs in mature gametocytes that were also low in antisense RNA expression in non-gametocyte stages. After testing numerous candidate mRNAs, the spliced female Pf3D7_0630000 mRNA was selected as a Plasmodium falciparum gametocyte-specific biomarker compatible with Plasmodium 18S rRNA RT-PCR. This mRNA was only detected in samples containing mature gametocytes and was absent in those containing only asexual stage parasites or uninfected human blood. PF3D7_0630000 RT-PCR detected gametocytes across a wide range of parasite densities in both spiked and clinical samples and agreed with pfs25 RT-PCR, the gold standard for RT-PCR-based gametocyte detection. PF3D7_0630000 multiplexed with Plasmodium 18S rRNA RT-PCR was more sensitive than other spliced mRNA targets for one-step RT-PCR gametocyte detection. Conclusions Because the spliced target does not require DNase treatment, the PF3D7_0630000 assay can be multiplexed with Plasmodium 18S rRNA for direct one-step detection of gametocytes from whole human blood. Electronic supplementary material The online version of this article (doi:10.1186/s12936-017-1863-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Amelia E Hanron
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Zachary P Billman
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA.,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican St., Seattle, WA, 98109, USA
| | - Annette M Seilie
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Tayla M Olsen
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Matthew Fishbaugher
- Center for Infectious Disease Research, 307 Westlake Ave. N, #500, Seattle, WA, 98109, USA
| | - Ming Chang
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA
| | - Thomas Rueckle
- Medicines for Malaria Venture, PO Box 1826, 20, Route de Pré-Bois, 1215, Geneva, Switzerland
| | - Nicole Andenmatten
- Medicines for Malaria Venture, PO Box 1826, 20, Route de Pré-Bois, 1215, Geneva, Switzerland
| | - Bryan Greenhouse
- Division of HIV, Infectious Diseases and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, USA
| | - Emmanuel Arinaitwe
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda.,London School of Hygiene & Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - John Rek
- Infectious Diseases Research Collaboration, 2C Nakasero Hill Road, PO Box 7475, Kampala, Uganda
| | - Smita Das
- PATH, 2201 Westlake Ave #200, Seattle, WA, 98121, USA
| | | | - Kelly Shipman
- Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, 1100 Fairview Ave. N., #E3-300, Seattle, WA, 98109, USA
| | - Stefan H Kappe
- Center for Infectious Disease Research, 307 Westlake Ave. N, #500, Seattle, WA, 98109, USA
| | - James G Kublin
- Seattle Malaria Clinical Trials Center, Fred Hutch Cancer Research Center, 1100 Fairview Ave. N., #E3-300, Seattle, WA, 98109, USA
| | - Sean C Murphy
- Department of Laboratory Medicine, University of Washington, 750 Republican St., E630, Seattle, WA, 98109, USA. .,Department of Microbiology, University of Washington, 1959 NE Pacific St., Seattle, WA, 98195, USA. .,Center for Emerging and Re-emerging Infectious Diseases, University of Washington, 750 Republican St., Seattle, WA, 98109, USA. .,Center for Infectious Disease Research, 307 Westlake Ave. N, #500, Seattle, WA, 98109, USA.
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Pett H, Gonçalves BP, Dicko A, Nébié I, Tiono AB, Lanke K, Bradley J, Chen I, Diawara H, Mahamar A, Soumare HM, Traore SF, Baber I, Sirima SB, Sauerwein R, Brown J, Gosling R, Felger I, Drakeley C, Bousema T. Comparison of molecular quantification of Plasmodium falciparum gametocytes by Pfs25 qRT-PCR and QT-NASBA in relation to mosquito infectivity. Malar J 2016; 15:539. [PMID: 27821171 PMCID: PMC5100312 DOI: 10.1186/s12936-016-1584-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 10/28/2016] [Indexed: 11/24/2022] Open
Abstract
Background Quantifying gametocyte densities in natural malaria infections is important to estimate malaria transmission potential. Two molecular methods (Pfs25 mRNA quantitative reverse transcriptase PCR (qRT-PCR) and Pfs25 mRNA quantitative nucleic acid sequence based amplification (QT-NASBA)) are commonly used to determine gametocyte densities in clinical and epidemiological studies and allow gametocyte detection at densities below the microscopic threshold for detection. Here, reproducibility of these measurements and the association between estimated gametocyte densities and mosquito infection rates were compared. Methods To quantify intra- and inter-assay variation of QT-NASBA and qRT-PCR, a series of experiments was performed using culture-derived mature Plasmodium falciparum gametocytes from three different parasite isolates (NF54, NF135, NF166). Pfs25 mRNA levels were also determined in samples from clinical trials in Mali and Burkina Faso using both methods. Agreement between the two methods and association with mosquito infection rates in membrane feeding assays were assessed. Results Intra- and inter-assay variability was larger in QT-NASBA compared to qRT-PCR, particularly at low gametocyte densities (< 1 gametocyte per μL). Logistic models, including log-transformed gametocytaemia estimated by QT-NASBA, explained variability in mosquito feeding experiment results as well as log-transformed gametocytaemia by qRT-PCR (marginal R2 0.28 and 0.22, respectively). Densities determined by both methods strongly correlated with mosquito infection rates [Spearman’s rank correlation coefficient, 0.59 for qRT-PCR and 0.64 for QT-NASBA (P < 0.001 for both)]. Gametocyte densities estimated by qRT-PCR were higher than levels estimated by QT-NASBA or light microscopy at high densities (>100 gametocyte per μL). Samples collected in one of the two transmission studies had extremely low gametocyte densities by both molecular methods, which is suggestive of RNA degradation due to an unknown number of freeze–thaw cycles and illustrates the reliance of molecular gametocyte diagnostics on a reliable cold-chain. Conclusions The experiments indicate that both qRT-PCR and QT-NASBA are of value for quantifying mature gametocytes in samples collected in field studies. For both assays, estimated gametocyte densities correlated well with mosquito infection rates. QT-NASBA is less reproducible than qRT-PCR, particularly for low gametocyte densities. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1584-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Helmi Pett
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6500 HB, Nijmegen, The Netherlands
| | - Bronner P Gonçalves
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Issa Nébié
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Alfred B Tiono
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6500 HB, Nijmegen, The Netherlands
| | - John Bradley
- MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Ingrid Chen
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Halimatou Diawara
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Almahamoudou Mahamar
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Harouna M Soumare
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sekou F Traore
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Ibrahima Baber
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Bamako, Mali
| | - Sodiomon B Sirima
- Centre National de Recherche et de Formation sur le Paludisme, Ouagadougou, Burkina Faso
| | - Robert Sauerwein
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6500 HB, Nijmegen, The Netherlands
| | - Joelle Brown
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Roly Gosling
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA
| | - Ingrid Felger
- Molecular Diagnostics Unit, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene & Tropical Medicine, London, UK
| | - Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Geert Grooteplein Zuid 26-28, 6500 HB, Nijmegen, The Netherlands.
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Coalson JE, Walldorf JA, Cohee LM, Ismail MD, Mathanga D, Cordy RJ, Marti M, Taylor TE, Seydel KB, Laufer MK, Wilson ML. High prevalence of Plasmodium falciparum gametocyte infections in school-age children using molecular detection: patterns and predictors of risk from a cross-sectional study in southern Malawi. Malar J 2016; 15:527. [PMID: 27809907 PMCID: PMC5096312 DOI: 10.1186/s12936-016-1587-9] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/28/2016] [Indexed: 01/11/2023] Open
Abstract
Background In endemic areas, many people experience asymptomatic Plasmodium infections, particularly older children and adults, but their transmission contribution is unknown. Though not the exclusive determinant of infectiousness, transmission from humans to mosquitoes requires blood meals containing gametocytes. Gametocytes often occur at submicroscopic densities, challenging measurement in human populations. More sensitive molecular techniques allow better characterization of gametocyte epidemiologic patterns. Methods Approximately 30 households were selected from each of eight sites in southern Malawi during two cross-sectional surveys. Blood was sampled from 623 people during the dry season and 896 the following rainy season. Among people PCR-positive for Plasmodium falciparum, mature gametocytes were detected by qRT-PCR. Regression models evaluated predictors of gametocyte carriage and density in the total population and among those with PCR-positive infections. Results The prevalence of gametocyte carriage by molecular testing was 3.5% during the dry season and 8.6% during the rainy season, and by microscopy 0.8 and 3.3%, respectively. Nearly half of PCR-positive infections carried gametocytes, regardless of recent symptom status. Among P. falciparum-infected people, only living in unfinished houses and age were significantly associated with gametocyte presence. Infected people in unfinished houses had higher odds of carrying gametocytes (OR 2.24, 95% CI 1.16–4.31), and 31% (95% CI 3–65%) higher gametocyte density than those in finished houses. School-age children (5–15 years), had higher odds than adults (≥16 years) of having gametocytes when infected (OR 2.77, 95% CI 1.47–5.19), but 31% (95% CI 11–47%) lower gametocyte density. Children <5 years did not have significantly higher odds of gametocyte carriage or density when infected than adults. Conclusions School-age children frequently carry gametocytes in communities of southern Malawi and represent an under-recognized reservoir of infection. Malaria elimination strategies should address these frequently asymptomatic reservoirs, especially in highly endemic areas. Improved household construction may also reduce the infectious reservoir. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1587-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jenna E Coalson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA.
| | - Jenny A Walldorf
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Lauren M Cohee
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Miriam D Ismail
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
| | - Don Mathanga
- Malaria Alert Centre, College of Medicine, University of Malawi, Blantyre, Malawi
| | - Regina Joice Cordy
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Matthias Marti
- Department of Immunology and Infectious Disease, The Harvard School of Public Health, Boston, MA, USA
| | - Terrie E Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Karl B Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, MI, USA
| | - Miriam K Laufer
- Division of Malaria Research, Institute for Global Health, University of Maryland, Baltimore, MD, USA
| | - Mark L Wilson
- Department of Epidemiology, University of Michigan School of Public Health, Ann Arbor, MI, USA
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30
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Diversity-oriented synthesis yields novel multistage antimalarial inhibitors. Nature 2016; 538:344-349. [PMID: 27602946 DOI: 10.1038/nature19804] [Citation(s) in RCA: 186] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 08/31/2016] [Indexed: 02/08/2023]
Abstract
Antimalarial drugs have thus far been chiefly derived from two sources-natural products and synthetic drug-like compounds. Here we investigate whether antimalarial agents with novel mechanisms of action could be discovered using a diverse collection of synthetic compounds that have three-dimensional features reminiscent of natural products and are underrepresented in typical screening collections. We report the identification of such compounds with both previously reported and undescribed mechanisms of action, including a series of bicyclic azetidines that inhibit a new antimalarial target, phenylalanyl-tRNA synthetase. These molecules are curative in mice at a single, low dose and show activity against all parasite life stages in multiple in vivo efficacy models. Our findings identify bicyclic azetidines with the potential to both cure and prevent transmission of the disease as well as protect at-risk populations with a single oral dose, highlighting the strength of diversity-oriented synthesis in revealing promising therapeutic targets.
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Plasmodium Helical Interspersed Subtelomeric (PHIST) Proteins, at the Center of Host Cell Remodeling. Microbiol Mol Biol Rev 2016; 80:905-27. [PMID: 27582258 DOI: 10.1128/mmbr.00014-16] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the asexual cycle, Plasmodium falciparum extensively remodels the human erythrocyte to make it a suitable host cell. A large number of exported proteins facilitate this remodeling process, which causes erythrocytes to become more rigid, cytoadherent, and permeable for nutrients and metabolic products. Among the exported proteins, a family of 89 proteins, called the Plasmodium helical interspersed subtelomeric (PHIST) protein family, has been identified. While also found in other Plasmodium species, the PHIST family is greatly expanded in P. falciparum. Although a decade has passed since their first description, to date, most PHIST proteins remain uncharacterized and are of unknown function and localization within the host cell, and there are few data on their interactions with other host or parasite proteins. However, over the past few years, PHIST proteins have been mentioned in the literature at an increasing rate owing to their presence at various localizations within the infected erythrocyte. Expression of PHIST proteins has been implicated in molecular and cellular processes such as the surface display of PfEMP1, gametocytogenesis, changes in cell rigidity, and also cerebral and pregnancy-associated malaria. Thus, we conclude that PHIST proteins are central to host cell remodeling, but despite their obvious importance in pathology, PHIST proteins seem to be understudied. Here we review current knowledge, shed light on the definition of PHIST proteins, and discuss these proteins with respect to their localization and probable function. We take into consideration interaction studies, microarray analyses, or data from blood samples from naturally infected patients to combine all available information on this protein family.
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Bahamontes-Rosa N, Gomez-Lorenzo MG, Lelièvre J, Rodriguez Alejandre A, Almela MJ, Lozano S, Herreros E, Gamo FJ. A novel validated assay to support the discovery of new anti-malarial gametocytocidal agents. Malar J 2016; 15:385. [PMID: 27448565 PMCID: PMC4957904 DOI: 10.1186/s12936-016-1429-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 07/05/2016] [Indexed: 11/21/2022] Open
Abstract
Background Drugs that kill or inhibit Plasmodium gametocytes in the human host could potentially synergize the impact of other chemotherapeutic interventions by blocking transmission. To develop such agents, reliable methods are needed to study the in vitro activity of compounds against gametocytes. This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of Plasmodium falciparum gametocyte development using real-time PCR (qPCR). Methods Genes previously reported to be transcribed at the different sexual stages of the gametocytogenesis were selected for study and their mRNA expression was measured in a gametocytogenesis course by qPCR. Genes mainly expressed in the later stages of gametocyte development were used as a surrogate measurement of drug activity. To distinguish between cidal and static drug effects, two different experiments were performed in parallel, one with constant drug pressure throughout the experiment (144 h), and another in which the gametocyte cultures were exposed to the compound for only 48 h. Results Four P.falciparum genes coding for proteins Pf77, ROM3, Pfs25, and Pfg377 with transcription specific for late-stage gametocyte development were identified. The in vitro anti-malarial activity of compounds against such gametocytes was assessed by measuring mRNA levels of these genes using qPCR. The assay was validated against standard anti-malarial drugs (epoxomicin, dihydroartemisinin, chloroquine, thiostrepton, and methylene blue) and compounds from the GSK compound library with known anti-gametocyte activity. Conclusions This study describes a novel assay for characterizing the activity of anti-malarial drugs against the later stages of P. falciparum gametocyte development using qPCR in genetically unmodified parasites. The method described is a reliable and user-friendly technique with a medium throughput that could be easily implemented in any laboratory. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1429-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Noemí Bahamontes-Rosa
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain.
| | - María G Gomez-Lorenzo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Joël Lelièvre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Ane Rodriguez Alejandre
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - María Jesus Almela
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Sonia Lozano
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Esperanza Herreros
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
| | - Francisco-Javier Gamo
- Tres Cantos Medicines Development Campus, Diseases of the Developing World, GlaxoSmithKline, Tres Cantos, 28760, Madrid, Spain
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Chang HH, Meibalan E, Zelin J, Daniels R, Eziefula AC, Meyer EC, Tadesse F, Grignard L, Joice RC, Drakeley C, Wirth DF, Volkman SK, Buckee C, Bousema T, Marti M. Persistence of Plasmodium falciparum parasitemia after artemisinin combination therapy: evidence from a randomized trial in Uganda. Sci Rep 2016; 6:26330. [PMID: 27197604 PMCID: PMC4873826 DOI: 10.1038/srep26330] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 05/03/2016] [Indexed: 11/12/2022] Open
Abstract
Artemisinin resistance is rapidly spreading in Southeast Asia. The efficacy of artemisinin-combination therapy (ACT) continues to be excellent across Africa. We performed parasite transcriptional profiling and genotyping on samples from an antimalarial treatment trial in Uganda. We used qRT-PCR and genotyping to characterize residual circulating parasite populations after treatment with either ACT or ACT-primaquine. Transcripts suggestive of circulating ring stage parasites were present after treatment at a prevalence of >25% until at least 14 days post initiation of treatment. Greater than 98% of all ring stage parasites were cleared within the first 3 days, but subsequently persisted at low concentrations until day 14 after treatment. Genotyping demonstrated a significant decrease in multiplicity of infection within the first 2 days in both ACT and ACT-primaquine arms. However, multiple clone infections persisted until day 14 post treatment. Our data suggest the presence of genetically diverse persisting parasite populations after ACT treatment. Although we did not demonstrate clinical treatment failures after ACT and the viability and transmissibility of persisting ring stage parasites remain to be shown, these findings are of relevance for the interpretation of parasite clearance transmission dynamics and for monitoring drug effects in Plasmodium falciparum parasites.
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Affiliation(s)
- Hsiao-Han Chang
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Elamaran Meibalan
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Justin Zelin
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Rachel Daniels
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Alice C Eziefula
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Evan C Meyer
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Fitsum Tadesse
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Lynn Grignard
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Regina C Joice
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Chris Drakeley
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK
| | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA
| | - Sarah K Volkman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA 02142, USA.,Simmons College, 300 Fenway, Boston, MA 02115, USA
| | - Caroline Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
| | - Teun Bousema
- Immunology and Infection Department, London School of Hygiene and Tropical Medicine, Keppel Street, London, WC1E 7HT, UK.,Institute for Molecular Life Sciences, Radboud University, Geert Grooteplain Zuid 28, 6525 GA Nijmegen, The Netherlands
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, 665 Huntington Ave, Boston, MA 02115, USA
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Pasay CJ, Rockett R, Sekuloski S, Griffin P, Marquart L, Peatey C, Wang CYT, O'Rourke P, Elliott S, Baker M, Möhrle JJ, McCarthy JS. Piperaquine Monotherapy of Drug-Susceptible Plasmodium falciparum Infection Results in Rapid Clearance of Parasitemia but Is Followed by the Appearance of Gametocytemia. J Infect Dis 2016; 214:105-13. [PMID: 27056954 PMCID: PMC4907420 DOI: 10.1093/infdis/jiw128] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/24/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Piperaquine, coformulated with dihydroartemisinin, is a component of a widely used artemisinin combination therapy. There is a paucity of data on its antimalarial activity as a single agent. Such data, if available, would inform selection of new coformulations. METHODS We undertook a study in healthy subjects, using the induced blood stage malaria (IBSM) model to test the antimalarial activity of single doses of piperaquine (960, 640, and 480 mg) in 3 cohorts. In a pilot study in the third cohort, gametocyte clearance following administration of 15 mg, or 45 mg or no primaquine was investigated. RESULTS Parasite clearance over the 48-hour period after piperaquine administration was more rapid in the 960 mg cohort, compared with the 640 mg cohort (parasite reduction ratio, 2951 [95% confidence interval {CI}, 1520-5728] vs 586 [95% CI, 351-978]; P < .001). All 24 subjects developed gametocytemia as determined by pfs25 transcripts. Clearance of pfs25 was significantly faster in those receiving primaquine than in those not receiving primaquine (P < .001). CONCLUSIONS Piperaquine possesses rapid parasite-clearing activity, but monotherapy is followed by the appearance of gametocytemia, which could facilitate the spread of malaria. This new information should be taken into account when developing future antimalarial coformulations. CLINICAL TRIALS REGISTRATION ACTRN12613000565741.
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Affiliation(s)
| | - Rebecca Rockett
- School of Chemistry and Molecular Biosciences Queensland Pediatric Infectious Diseases Laboratory
| | | | - Paul Griffin
- QIMR Berghofer Medical Research Institute School of Medicine, University of Queensland Q-Pharm Department of Infectious Diseases, Mater Health Services and Mater Research Institute
| | | | | | | | | | | | | | | | - James S McCarthy
- QIMR Berghofer Medical Research Institute School of Medicine, University of Queensland Q-Pharm
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Abstract
Gametocytes are the specialized form of Plasmodium parasites that are responsible for human-to-mosquito transmission of malaria. Transmission of gametocytes is highly effective, but represents a biomass bottleneck for the parasite that has stimulated interest in strategies targeting the transmission stages separately from those responsible for clinical disease. Studying targets of naturally acquired immunity against transmission-stage parasites may reveal opportunities for novel transmission reducing interventions, particularly the development of a transmission blocking vaccine (TBV). In this review, we summarize the current knowledge on immunity against the transmission stages of Plasmodium. This includes immune responses against epitopes on the gametocyte-infected erythrocyte surface during gametocyte development, as well as epitopes present upon gametocyte activation in the mosquito midgut. We present an analysis of historical data on transmission reducing immunity (TRI), as analysed in mosquito feeding assays, and its correlation with natural recognition of sexual stage specific proteins Pfs48/45 and Pfs230. Although high antibody titres towards either one of these proteins is associated with TRI, the presence of additional, novel targets is anticipated. In conclusion, the identification of novel gametocyte-specific targets of naturally acquired immunity against different gametocyte stages could aid in the development of potential TBV targets and ultimately an effective transmission blocking approach.
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Abdul-Ghani R, Basco LK, Beier JC, Mahdy MAK. Inclusion of gametocyte parameters in anti-malarial drug efficacy studies: filling a neglected gap needed for malaria elimination. Malar J 2015; 14:413. [PMID: 26481312 PMCID: PMC4617745 DOI: 10.1186/s12936-015-0936-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/09/2015] [Indexed: 11/29/2022] Open
Abstract
Standard anti-malarial drug efficacy and drug resistance assessments neglect the gametocyte parameters in their protocols. With the spread of drug resistance and the absence of clinically proven vaccines, the use of gametocytocidal drugs or drug combinations with transmission-blocking activity is a high priority for malaria control and elimination. However, the limited repertoire of gametocytocidal drugs and induction of gametocytogenesis after treatment with certain anti-malarial drugs necessitate both regular monitoring
of gametocytocidal activities of anti-malarial drugs in clinical use and the effectiveness of candidate gametocytocidal agents. Therefore, updating current protocols of anti-malarial drug efficacy is needed to reflect the effects of anti-malarial drugs or drug combinations on gametocyte carriage and gametocyte density along with asexual parasite density. Developing protocols of anti-malarial drug efficacy that include gametocyte parameters related to both microscopic and submicroscopic gametocytaemias is important if drugs or drug combinations are to be strategically used in transmission-blocking interventions in the context of malaria elimination. The present piece of opinion highlights the challenges in gametocyte detection and follow-up and discuss the need for including the gametocyte parameter in anti-malarial efficacy studies.
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Affiliation(s)
- Rashad Abdul-Ghani
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen. .,Tropical Disease Research Center, University of Science and Technology, Sana'a, Yemen.
| | - Leonardo K Basco
- Unité de Recherche 198, Unité de Recherche sur les Maladies Infectieuses et Tropicales Emergentes, Institut de Recherche pour le Développement, Faculté de Médecine La Timone, Aix-Marseille Université, Marseille, France.
| | - John C Beier
- Department of Public Health Sciences, University of Miami Miller School of Medicine, Miami, FL, USA.
| | - Mohammed A K Mahdy
- Department of Parasitology, Faculty of Medicine and Health Sciences, Sana'a University, Sana'a, Yemen. .,Tropical Disease Research Center, University of Science and Technology, Sana'a, Yemen.
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Swann J, Jamshidi N, Lewis NE, Winzeler EA. Systems analysis of host-parasite interactions. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2015; 7:381-400. [PMID: 26306749 PMCID: PMC4679367 DOI: 10.1002/wsbm.1311] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/25/2015] [Accepted: 06/29/2015] [Indexed: 12/16/2022]
Abstract
Parasitic diseases caused by protozoan pathogens lead to hundreds of thousands of deaths per year in addition to substantial suffering and socioeconomic decline for millions of people worldwide. The lack of effective vaccines coupled with the widespread emergence of drug‐resistant parasites necessitates that the research community take an active role in understanding host–parasite infection biology in order to develop improved therapeutics. Recent advances in next‐generation sequencing and the rapid development of publicly accessible genomic databases for many human pathogens have facilitated the application of systems biology to the study of host–parasite interactions. Over the past decade, these technologies have led to the discovery of many important biological processes governing parasitic disease. The integration and interpretation of high‐throughput ‐omic data will undoubtedly generate extraordinary insight into host–parasite interaction networks essential to navigate the intricacies of these complex systems. As systems analysis continues to build the foundation for our understanding of host–parasite biology, this will provide the framework necessary to drive drug discovery research forward and accelerate the development of new antiparasitic therapies. WIREs Syst Biol Med 2015, 7:381–400. doi: 10.1002/wsbm.1311 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Justine Swann
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Neema Jamshidi
- Department of Radiological Sciences, University of California, Los Angeles, Los Angeles, CA, USA.,Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Nathan E Lewis
- Department of Pediatrics and Novo Nordisk Foundation Center for Biosustainability, University of California, San Diego, La Jolla, CA, USA
| | - Elizabeth A Winzeler
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
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38
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Abstract
Malaria remains one of the leading causes of death worldwide, despite decades of public health efforts. The recent commitment by many endemic countries to eliminate malaria marks a shift away from programs aimed at controlling disease burden towards one that emphasizes reducing transmission of the most virulent human malaria parasite, Plasmodium falciparum. Gametocytes, the only developmental stage of malaria parasites able to infect mosquitoes, have remained understudied, as they occur in low numbers, do not cause disease, and are difficult to detect in vivo by conventional methods. Here, we review the transmission biology of P. falciparum gametocytes, featuring important recent discoveries of genes affecting parasite commitment to gametocyte formation, microvesicles enabling parasites to communicate with each other, and the anatomical site where immature gametocytes develop. We propose potential parasite targets for future intervention and highlight remaining knowledge gaps.
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Affiliation(s)
- Sandra K. Nilsson
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Lauren M. Childs
- Centre for Communicable Disease Dynamics and Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Caroline Buckee
- Centre for Communicable Disease Dynamics and Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- * E-mail: (CB); (MM)
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, United States of America
- * E-mail: (CB); (MM)
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Broadbent KM, Broadbent JC, Ribacke U, Wirth D, Rinn JL, Sabeti PC. Strand-specific RNA sequencing in Plasmodium falciparum malaria identifies developmentally regulated long non-coding RNA and circular RNA. BMC Genomics 2015; 16:454. [PMID: 26070627 PMCID: PMC4465157 DOI: 10.1186/s12864-015-1603-4] [Citation(s) in RCA: 127] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/01/2015] [Indexed: 11/21/2022] Open
Abstract
Background The human malaria parasite Plasmodium falciparum has a complex and multi-stage life cycle that requires extensive and precise gene regulation to allow invasion and hijacking of host cells, transmission, and immune escape. To date, the regulatory elements orchestrating these critical parasite processes remain largely unknown. Yet it is becoming increasingly clear that long non-coding RNAs (lncRNAs) could represent a missing regulatory layer across a broad range of organisms. Results To investigate the regulatory capacity of lncRNA in P. falciparum, we harvested fifteen samples from two time-courses. Our sample set profiled 56 h of P. falciparum blood stage development. We then developed and validated strand-specific, non-polyA-selected RNA sequencing methods, and pursued the first assembly of P. falciparum strand-specific transcript structures from RNA sequencing data. This approach enabled the annotation of over one thousand lncRNA transcript models and their comprehensive global analysis: coding prediction, periodicity, stage-specificity, correlation, GC content, length, location relative to annotated transcripts, and splicing. We validated the complete splicing structure of three lncRNAs with compelling properties. Non-polyA-selected deep sequencing also enabled the prediction of hundreds of intriguing P. falciparum circular RNAs, six of which we validated experimentally. Conclusions We found that a subset of lncRNAs, including all subtelomeric lncRNAs, strongly peaked in expression during invasion. By contrast, antisense transcript levels significantly dropped during invasion. As compared to neighboring mRNAs, the expression of antisense-sense pairs was significantly anti-correlated during blood stage development, indicating transcriptional interference. We also validated that P. falciparum produces circRNAs, which is notable given the lack of RNA interference in the organism, and discovered that a highly expressed, five-exon antisense RNA is poised to regulate P. falciparum gametocyte development 1 (PfGDV1), a gene required for early sexual commitment events. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1603-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kate M Broadbent
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA. .,Broad Institute, Cambridge, Massachusetts, USA.
| | - Jill C Broadbent
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA. .,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.
| | - Ulf Ribacke
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA. .,Department of Cell and Molecular Biology, BMC, Uppsala University, Uppsala, Sweden.
| | - Dyann Wirth
- Broad Institute, Cambridge, Massachusetts, USA. .,Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, USA.
| | - John L Rinn
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA. .,Broad Institute, Cambridge, Massachusetts, USA. .,Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts, USA.
| | - Pardis C Sabeti
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts, USA. .,Broad Institute, Cambridge, Massachusetts, USA. .,FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA. .,Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts, USA.
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40
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Pelle KG, Oh K, Buchholz K, Narasimhan V, Joice R, Milner DA, Brancucci NM, Ma S, Voss TS, Ketman K, Seydel KB, Taylor TE, Barteneva NS, Huttenhower C, Marti M. Transcriptional profiling defines dynamics of parasite tissue sequestration during malaria infection. Genome Med 2015; 7:19. [PMID: 25722744 PMCID: PMC4342211 DOI: 10.1186/s13073-015-0133-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/15/2015] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND During intra-erythrocytic development, late asexually replicating Plasmodium falciparum parasites sequester from peripheral circulation. This facilitates chronic infection and is linked to severe disease and organ-specific pathology including cerebral and placental malaria. Immature gametocytes - sexual stage precursor cells - likewise disappear from circulation. Recent work has demonstrated that these sexual stage parasites are located in the hematopoietic system of the bone marrow before mature gametocytes are released into the bloodstream to facilitate mosquito transmission. However, as sequestration occurs only in vivo and not during in vitro culture, the mechanisms by which it is regulated and enacted (particularly by the gametocyte stage) remain poorly understood. RESULTS We generated the most comprehensive P. falciparum functional gene network to date by integrating global transcriptional data from a large set of asexual and sexual in vitro samples, patient-derived in vivo samples, and a new set of in vitro samples profiling sexual commitment. We defined more than 250 functional modules (clusters) of genes that are co-expressed primarily during the intra-erythrocytic parasite cycle, including 35 during sexual commitment and gametocyte development. Comparing the in vivo and in vitro datasets allowed us, for the first time, to map the time point of asexual parasite sequestration in patients to 22 hours post-invasion, confirming previous in vitro observations on the dynamics of host cell modification and cytoadherence. Moreover, we were able to define the properties of gametocyte sequestration, demonstrating the presence of two circulating gametocyte populations: gametocyte rings between 0 and approximately 30 hours post-invasion and mature gametocytes after around 7 days post-invasion. CONCLUSIONS This study provides a bioinformatics resource for the functional elucidation of parasite life cycle dynamics and specifically demonstrates the presence of the gametocyte ring stages in circulation, adding significantly to our understanding of the dynamics of gametocyte sequestration in vivo.
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Affiliation(s)
- Karell G Pelle
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA
| | - Keunyoung Oh
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115 USA
| | - Kathrin Buchholz
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA
| | - Vagheesh Narasimhan
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115 USA
| | - Regina Joice
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA
| | - Danny A Milner
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA ; Department of Pathology, Brigham and Women's Hospital, Boston, MA 02115 USA
| | - Nicolas Mb Brancucci
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA ; Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
| | - Siyuan Ma
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115 USA
| | - Till S Voss
- Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland
| | - Ken Ketman
- Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA 02115 USA
| | - Karl B Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48825 USA ; Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, 3 Malawi
| | - Terrie E Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing, MI 48825 USA ; Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, 3 Malawi
| | - Natasha S Barteneva
- Program in Cellular and Molecular Medicine, Children's Hospital, Boston, MA 02115 USA ; Department of Pediatrics, Harvard Medical School, Boston, MA 02115 USA
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard School of Public Health, Boston, MA 02115 USA ; The Broad Institute of Harvard and MIT, Cambridge, MA 02142 USA
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA 02115 USA
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Van Tyne D, Tan Y, Daily JP, Kamiza S, Seydel K, Taylor T, Mesirov JP, Wirth DF, Milner DA. Plasmodium falciparum gene expression measured directly from tissue during human infection. Genome Med 2014; 6:110. [PMID: 25520756 PMCID: PMC4269068 DOI: 10.1186/s13073-014-0110-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 11/14/2014] [Indexed: 02/08/2023] Open
Abstract
Background During the latter half of the natural 48-h intraerythrocytic life cycle of human Plasmodium falciparum infection, parasites sequester deep in endothelium of tissues, away from the spleen and inaccessible to peripheral blood. These late-stage parasites may cause tissue damage and likely contribute to clinical disease, and a more complete understanding of their biology is needed. Because these life cycle stages are not easily sampled due to deep tissue sequestration, measuring in vivo gene expression of parasites in the trophozoite and schizont stages has been a challenge. Methods We developed a custom nCounter® gene expression platform and used this platform to measure malaria parasite gene expression profiles in vitro and in vivo. We also used imputation to generate global transcriptional profiles and assessed differential gene expression between parasites growing in vitro and those recovered from malaria-infected patient tissues collected at autopsy. Results We demonstrate, for the first time, global transcriptional expression profiles from in vivo malaria parasites sequestered in human tissues. We found that parasite physiology can be correlated with in vitro data from an existing life cycle data set, and that parasites in sequestered tissues show an expected schizont-like transcriptional profile, which is conserved across tissues from the same patient. Imputation based on 60 landmark genes generated global transcriptional profiles that were highly correlated with genome-wide expression patterns from the same samples measured by microarray. Finally, differential expression revealed a limited set of in vivo upregulated transcripts, which may indicate unique parasite genes involved in human clinical infections. Conclusions Our study highlights the utility of a custom nCounter® P. falciparum probe set, validation of imputation within Plasmodium species, and documentation of in vivo schizont-stage expression patterns from human tissues. Electronic supplementary material The online version of this article (doi:10.1186/s13073-014-0110-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daria Van Tyne
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA USA
| | - Yan Tan
- Broad Institute, Cambridge, MA USA ; Graduate Program in Bioinformatics, Boston University, Boston, MA USA
| | | | - Steve Kamiza
- University of Malawi College of Medicine, Blantyre, Malawi
| | - Karl Seydel
- Michigan State University, College of Osteopathic Medicine, East Lansing, MI USA ; The Blantyre Malaria Project, Blantyre, Malawi
| | - Terrie Taylor
- Michigan State University, College of Osteopathic Medicine, East Lansing, MI USA ; The Blantyre Malaria Project, Blantyre, Malawi
| | | | - Dyann F Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA USA ; Broad Institute, Cambridge, MA USA
| | - Danny A Milner
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA USA ; Broad Institute, Cambridge, MA USA ; University of Malawi College of Medicine, Blantyre, Malawi ; The Blantyre Malaria Project, Blantyre, Malawi ; Brigham and Women's Hospital, Boston, MA USA
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42
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Tao D, Ubaida-Mohien C, Mathias DK, King JG, Pastrana-Mena R, Tripathi A, Goldowitz I, Graham DR, Moss E, Marti M, Dinglasan RR. Sex-partitioning of the Plasmodium falciparum stage V gametocyte proteome provides insight into falciparum-specific cell biology. Mol Cell Proteomics 2014; 13:2705-24. [PMID: 25056935 PMCID: PMC4188997 DOI: 10.1074/mcp.m114.040956] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
One of the critical gaps in malaria transmission biology and surveillance is our lack of knowledge about Plasmodium falciparum gametocyte biology, especially sexual dimorphic development and how sex ratios that may influence transmission from the human to the mosquito. Dissecting this process has been hampered by the lack of sex-specific protein markers for the circulating, mature stage V gametocytes. The current evidence suggests a high degree of conservation in gametocyte gene complement across Plasmodium, and therefore presumably for sex-specific genes as well. To better our understanding of gametocyte development and subsequent infectiousness to mosquitoes, we undertook a Systematic Subtractive Bioinformatic analysis (filtering) approach to identify sex-specific P. falciparum NF54 protein markers based on a comparison with the Dd2 strain, which is defective in producing males, and with syntenic male and female proteins from the reanalyzed and updated P. berghei (related rodent malaria parasite) gametocyte proteomes. This produced a short list of 174 male- and 258 female-enriched P. falciparum stage V proteins, some of which appear to be under strong diversifying selection, suggesting ongoing adaptation to mosquito vector species. We generated antibodies against three putative female-specific gametocyte stage V proteins in P. falciparum and confirmed either conserved sex-specificity or the lack of cross-species sex-partitioning. Finally, our study provides not only an additional resource for mass spectrometry-derived evidence for gametocyte proteins but also lays down the foundation for rational screening and development of novel sex-partitioned protein biomarkers and transmission-blocking vaccine candidates.
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Affiliation(s)
- Dingyin Tao
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA
| | - Ceereena Ubaida-Mohien
- §Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, Maryland, USA
| | - Derrick K Mathias
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA
| | - Jonas G King
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA
| | - Rebecca Pastrana-Mena
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA
| | - Abhai Tripathi
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA
| | - Ilana Goldowitz
- ¶Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, USA
| | - David R Graham
- §Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, 733 N. Broadway, Baltimore, Maryland, USA
| | - Eli Moss
- ‖The Broad Institute, 7 Cambridge Center, Cambridge, Massachusetts, USA
| | - Matthias Marti
- ¶Department of Immunology and Infectious Diseases, Harvard School of Public Health, 665 Huntington Avenue, Boston, Massachusetts, USA
| | - Rhoel R Dinglasan
- From the ‡W. Harry Feinstone Department of Molecular Microbiology and Immunology and the Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore, Maryland, USA;
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