151
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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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152
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Abstract
Fighting infections and developing novel drugs and vaccines requires advanced knowledge of pathogen's biology. Readily accessible genomic, functional genomic, and population data aids biological and translational discovery. The Eukaryotic Pathogen Database Resources ( http://eupathdb.org ) are data mining resources that support hypothesis driven research by facilitating the discovery of meaningful biological relationships from large volumes of data. The resource encompasses 13 sites that support over 170 species including pathogenic protists, oomycetes, and fungi as well as evolutionarily related nonpathogenic species. EuPathDB integrates preanalyzed data with advanced search capabilities, data visualization, analysis tools and a comprehensive record system in a graphical interface that does not require prior computational skills. This chapter describes guiding concepts common across EuPathDB sites and illustrates the powerful data mining capabilities of some of the available tools and features.
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153
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Essuman E, Grabias B, Verma N, Chorazeczewski JK, Tripathi AK, Mlambo G, Addison EA, Amoah AGB, Quakyi I, Oakley MS, Kumar S. A Novel Gametocyte Biomarker for Superior Molecular Detection of the Plasmodium falciparum Infectious Reservoirs. J Infect Dis 2017; 216:1264-1272. [PMID: 28968664 DOI: 10.1093/infdis/jix442] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Accepted: 08/22/2017] [Indexed: 01/15/2023] Open
Abstract
Background Complete malaria eradication and optimal use of transmission-reducing interventions require knowledge of submicroscopic infectious reservoirs among asymptomatic individuals. Even submicroscopic levels of Plasmodium falciparum gametocytes can infect mosquitoes and promote onward transmission. Most efforts to identify gametocyte carriers use polymerase chain reaction amplification of the gametocyte-specific transcript Pfs25. Methods To expand the repertoire of biomarkers available for superior gametocyte detection, we compared the gene expression profiles of gametocytes and asynchronous blood-stage P. falciparum parasites by microarray technology. This allowed the identification of 56 molecules abundantly expressed in the gametocyte stage of the parasite. The analytical sensitivity for gametocyte detection was evaluated for 25 genes with the highest expression levels. Results One candidate, Pfg17, exhibited superior analytical sensitivity against a panel of gametocyte-spiked whole blood, detecting 10 gametocytes/mL; in comparison, Pfs25 detected only 25.3 gametocytes/mL. Pfg17 also exhibited superior clinical sensitivity, identifying 19.1% more samples from blood-film microscopy-negative Ghanaian children and 40% more samples from asymptomatic adults as gametocyte positive. Conclusions Cumulatively, our results suggest Pfg17 is an excellent biomarker for detecting asymptomatic infectious reservoirs otherwise missed by the most sensitive molecular method available. Our study has also improved the repertoire of transmission-stage antigens available for evaluation as candidate vaccines.
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Affiliation(s)
- Edward Essuman
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases
| | - Bryan Grabias
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases
| | - Nitin Verma
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases
| | - Joanna K Chorazeczewski
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring
| | - Abhai K Tripathi
- Johns Hopkins Malaria Research Institute.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland
| | - Godfree Mlambo
- Johns Hopkins Malaria Research Institute.,Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland
| | - Ebenezer A Addison
- School of Public Health, College of Health Sciences, University of Ghana, Legon
| | - Albert G B Amoah
- School of Public Health, College of Health Sciences, University of Ghana, Legon
| | - Isabella Quakyi
- School of Public Health, College of Health Sciences, University of Ghana, Legon
| | - Miranda S Oakley
- Laboratory of Mucosal Pathogens and Cellular Immunology, Division of Bacterial, Parasitic, and Allergenic Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring
| | - Sanjai Kumar
- Laboratory of Emerging Pathogens, Division of Emerging and Transfusion Transmitted Diseases
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154
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Voorberg-van der Wel A, Roma G, Gupta DK, Schuierer S, Nigsch F, Carbone W, Zeeman AM, Lee BH, Hofman SO, Faber BW, Knehr J, Pasini E, Kinzel B, Bifani P, Bonamy GMC, Bouwmeester T, Kocken CHM, Diagana TT. A comparative transcriptomic analysis of replicating and dormant liver stages of the relapsing malaria parasite Plasmodium cynomolgi. eLife 2017; 6:29605. [PMID: 29215331 PMCID: PMC5758109 DOI: 10.7554/elife.29605] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 12/05/2017] [Indexed: 01/23/2023] Open
Abstract
Plasmodium liver hypnozoites, which cause disease relapse, are widely considered to be the last barrier towards malaria eradication. The biology of this quiescent form of the parasite is poorly understood which hinders drug discovery. We report a comparative transcriptomic dataset of replicating liver schizonts and dormant hypnozoites of the relapsing parasite Plasmodium cynomolgi. Hypnozoites express only 34% of Plasmodium physiological pathways, while 91% are expressed in replicating schizonts. Few known malaria drug targets are expressed in quiescent parasites, but pathways involved in microbial dormancy, maintenance of genome integrity and ATP homeostasis were robustly expressed. Several transcripts encoding heavy metal transporters were expressed in hypnozoites and the copper chelator neocuproine was cidal to all liver stage parasites. This transcriptomic dataset is a valuable resource for the discovery of vaccines and effective treatments to combat vivax malaria.
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Affiliation(s)
| | - Guglielmo Roma
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | - Sven Schuierer
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Florian Nigsch
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Walter Carbone
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Anne-Marie Zeeman
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Boon Heng Lee
- Novartis Institute for Tropical Diseases, Singapore, Singapore
| | - Sam O Hofman
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Bart W Faber
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Judith Knehr
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Erica Pasini
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, Netherlands
| | - Bernd Kinzel
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Pablo Bifani
- Novartis Institute for Tropical Diseases, Singapore, Singapore
| | | | | | - Clemens H M Kocken
- Department of Parasitology, Biomedical Primate Research Centre, Rijswijk, Netherlands
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155
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Bousema T, Drakeley C. Determinants of Malaria Transmission at the Population Level. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a025510. [PMID: 28242786 DOI: 10.1101/cshperspect.a025510] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Transmission of malaria from man to mosquito defines the human infectious reservoir of malaria. At the population level this is influenced by a variety of human, parasite, and mosquito vector factors some or all of which may vary depending on the epidemiological setting. Here, we review our current state of knowledge related to human infectiousness to mosquitoes and how current malaria control strategies might be adapted to focus on reducing this. While much progress has been made in malaria control, we argue that an improved understanding of human infectivity will allow more effective use of current control tools and make elimination a more feasible goal.
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Affiliation(s)
- Teun Bousema
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen 6525 GA, The Netherlands.,Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
| | - Chris Drakeley
- Department of Immunology & Infection, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom
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156
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Santolamazza F, Avellino P, Siciliano G, Yao FA, Lombardo F, Ouédraogo JB, Modiano D, Alano P, Mangano VD. Detection of Plasmodium falciparum male and female gametocytes and determination of parasite sex ratio in human endemic populations by novel, cheap and robust RTqPCR assays. Malar J 2017; 16:468. [PMID: 29149898 PMCID: PMC5693539 DOI: 10.1186/s12936-017-2118-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Accepted: 11/11/2017] [Indexed: 11/18/2022] Open
Abstract
Background The presence of Plasmodium falciparum gametocytes in peripheral blood is essential for human to mosquito parasite transmission. The detection of submicroscopic infections with gametocytes and the estimation of the gametocyte sex ratio are crucial to assess the human host potential ability to infect mosquitoes and transmit malaria parasites. Aim and objectives The aim of this work was to develop sensitive and cheap Real Time qPCR assays for large-scale epidemiological surveys, based on detection and amplification of gametocyte sex specific transcripts selected from the literature: the female-specific pfs25 and pf glycerol kinase (pfGK) and the male-specific pfs230p and pf13 transcripts. Methods RTqPCR assays were used to test the gametocyte- and sex-specific expression of the target genes using asexual stages of the gametocyteless parasite clone F12 and FACS purified male and female gametocytes of the PfDynGFP/P47mCherry line. Assays were performed on 50 blood samples collected during an epidemiological survey in the Soumousso village, Burkina Faso, West-Africa, and amplification of the human housekeeping gene 18S rRNA was employed to normalize RNA sample variability. Results SYBR Green assays were developed that showed higher sensitivity compared to Taqman assays at a reduced cost. RTqPCR results confirmed that expression of pfs25 and pfs230p are female and male-specific, respectively, and introduced two novel markers, the female-specific pfGK and the male-specific pf13. A formula was derived to calculate the ratio of male to female gametocytes based on the ratio of male to female transcript copy number. Use of these assays in the field samples showed, as expected, a higher sensitivity of RTqPCR compared to microscopy. Importantly, similar values of gametocyte sex-ratio were obtained in the field samples based on the four different target combinations. Conclusion Novel, sensitive, cheap and robust molecular assays were developed for the detection and quantification of female and male P. falciparum gametocytes. In particular, the RTqPCR assays based on the female-specific pfs25 and the newly described male gametocyte-specific pf13 transcripts, including normalization by the human 18S, reliably assess presence and abundance of female and male gametocytes and enable to determine their sex-ratio in human subjects in endemic areas. Electronic supplementary material The online version of this article (10.1186/s12936-017-2118-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Federica Santolamazza
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Roma, Italy
| | - Pamela Avellino
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Roma, Italy
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Roma, Italy
| | - Franck Adama Yao
- Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso
| | - Fabrizio Lombardo
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Roma, Italy
| | - Jean Bosco Ouédraogo
- Institut de Recherche en Sciences de la Santé, Bobo Dioulasso, Burkina Faso.,Centre Muraz, Bobo Dioulasso, Burkina Faso
| | - David Modiano
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Roma, Italy
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Roma, Italy.
| | - Valentina Dianora Mangano
- Dipartimento di Sanità Pubblica e Malattie Infettive, Sapienza Università di Roma, Roma, Italy. .,Dipartimento di Ricerca Traslazionale e Nuove Tecnologie in Medicina e Chirurgia, Università di Pisa, Pisa, Italy.
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157
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Zuck M, Austin LS, Danziger SA, Aitchison JD, Kaushansky A. The Promise of Systems Biology Approaches for Revealing Host Pathogen Interactions in Malaria. Front Microbiol 2017; 8:2183. [PMID: 29201016 PMCID: PMC5696578 DOI: 10.3389/fmicb.2017.02183] [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: 09/10/2017] [Accepted: 10/24/2017] [Indexed: 12/18/2022] Open
Abstract
Despite global eradication efforts over the past century, malaria remains a devastating public health burden, causing almost half a million deaths annually (WHO, 2016). A detailed understanding of the mechanisms that control malaria infection has been hindered by technical challenges of studying a complex parasite life cycle in multiple hosts. While many interventions targeting the parasite have been implemented, the complex biology of Plasmodium poses a major challenge, and must be addressed to enable eradication. New approaches for elucidating key host-parasite interactions, and predicting how the parasite will respond in a variety of biological settings, could dramatically enhance the efficacy and longevity of intervention strategies. The field of systems biology has developed methodologies and principles that are well poised to meet these challenges. In this review, we focus our attention on the Liver Stage of the Plasmodium lifecycle and issue a “call to arms” for using systems biology approaches to forge a new era in malaria research. These approaches will reveal insights into the complex interplay between host and pathogen, and could ultimately lead to novel intervention strategies that contribute to malaria eradication.
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Affiliation(s)
- Meghan Zuck
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, WA, United States
| | - Laura S Austin
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, WA, United States
| | - Samuel A Danziger
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, WA, United States.,Institute for Systems Biology, Seattle, WA, United States
| | - John D Aitchison
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, WA, United States.,Institute for Systems Biology, Seattle, WA, United States
| | - Alexis Kaushansky
- Center for Infectious Disease Research, formerly Seattle Biomedical Research Institute, Seattle, WA, United States.,Department of Global Health, University of Washington, Seattle, WA, United States
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158
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Wang J, Zheng W, Liu F, Wang Y, He Y, Zheng L, Fan Q, Luo E, Cao Y, Cui L. Characterization of Pb51 in Plasmodium berghei as a malaria vaccine candidate targeting both asexual erythrocytic proliferation and transmission. Malar J 2017; 16:458. [PMID: 29132428 PMCID: PMC5683326 DOI: 10.1186/s12936-017-2107-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 11/02/2017] [Indexed: 11/10/2022] Open
Abstract
Background A vaccine that targets multiple developmental stages of malaria parasites would be an effective tool for malaria control and elimination. Methods A conserved gene in Plasmodium, the Plasmodium berghei gene (PBANKA_020570) encoding a 51 kDa protein (pb51 gene), was identified through search of the PlasmoDB database using a combination of expression and protein localization criteria. A partial domain of the Pb51 protein was expressed in a prokaryotic expression system (rPb51) and used for immunization in mice. The protein expression profile and localization were studied by Western blot and indirect immunofluorescence assay (IFA), respectively. The inhibitory effect of the anti-rPb51 antibodies on parasite proliferation was evaluated in erythrocytes in vivo. The transmission-blocking activity of the immune sera was determined by in vitro ookinete conversion assay and by direct mosquito feeding assay (DFA). Results The rPb51 elicited specific antibodies in mice. Western blot confirmed Pb51 expression in schizonts, gametocytes and ookinetes. IFA showed localization of Pb51 on the outer membranes of schizonts, gametocytes, zygotes, retorts, ookinetes and sporozoites of P. berghei. Mice immunized with the rPb51 protein significantly reduced parasite proliferation and gametocyte conversion in vivo. Moreover, the rPb51 antisera also significantly reduced the in vitro ookinete conversion when added into the ookinete culture medium. In DFA, mice immunized with the rPb51 reduced the prevalence of mosquito infection by 21.3% and oocyst density by 54.8%. Conclusions In P. berghei, P51 was expressed in both asexual erythrocytic and sexual stages and localized on the surface of these stages with the exception of the ring stage. The anti-rPb51 antibodies inhibited both P. berghei proliferation in mice and transmission of the parasite to mosquitoes. Electronic supplementary material The online version of this article (10.1186/s12936-017-2107-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Wenqi Zheng
- Laboratory of Surgery, The Affiliated Hospital, Inner Mongolia Medical University, Hohhot, 010050, China
| | - Fei Liu
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yaru Wang
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yiwen He
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Li Zheng
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Qi Fan
- Dalian Institute of Biotechnology, Dalian, Liaoning, China
| | - Enjie Luo
- Department of Pathogen Biology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China.
| | - Liwang Cui
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, 110001, Liaoning, China.,Department of Entomology, Pennsylvania State University, University Park, PA, 16802, USA
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159
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Plasmodium falciparum Calcium-Dependent Protein Kinase 2 Is Critical for Male Gametocyte Exflagellation but Not Essential for Asexual Proliferation. mBio 2017; 8:mBio.01656-17. [PMID: 29042501 PMCID: PMC5646254 DOI: 10.1128/mbio.01656-17] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Drug development efforts have focused mostly on the asexual blood stages of the malaria parasite Plasmodium falciparum. Except for primaquine, which has its own limitations, there are no available drugs that target the transmission of the parasite to mosquitoes. Therefore, there is a need to validate new parasite proteins that can be targeted for blocking transmission. P. falciparum calcium-dependent protein kinases (PfCDPKs) play critical roles at various stages of the parasite life cycle and, importantly, are absent in the human host. These features mark them as attractive drug targets. In this study, using CRISPR/Cas9 we successfully knocked out PfCDPK2 from blood-stage parasites, which was previously thought to be an indispensable protein. The growth rate of the PfCDPK2 knockout (KO) parasites was similar to that of wild-type parasites, confirming that PfCDPK2 function is not essential for the asexual proliferation of the parasite in vitro. The mature male and female gametocytes of PfCDPK2 KO parasites become round after induction. However, they fail to infect female Anopheles stephensi mosquitoes due to a defect(s) in male gametocyte exflagellation and possibly in female gametes. Despite reductions in the number of deaths it causes, malaria continues to be a leading infectious disease of the developing world. For effective control and elimination of malaria, multiple stages of the parasite need to be targeted. One such stage includes the transmission of the parasite to mosquitoes. Here, we demonstrate the successful knockout of PfCDPK2, which was previously thought to be indispensable for parasite growth in red blood cells. The PfCDPK2 KO parasites are incapable of establishing an infection in mosquitoes. Therefore, our study suggests that targeting PfCDPK2 may be a good strategy to control malaria transmission in countries with high transmission. Moreover, molecular understanding of the signaling pathway of PfCDPK2 may provide additional targets for malaria control.
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160
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Stone W, Sawa P, Lanke K, Rijpma S, Oriango R, Nyaurah M, Osodo P, Osoti V, Mahamar A, Diawara H, Woestenenk R, Graumans W, van de Vegte-Bolmer M, Bradley J, Chen I, Brown J, Siciliano G, Alano P, Gosling R, Dicko A, Drakeley C, Bousema T. A Molecular Assay to Quantify Male and Female Plasmodium falciparum Gametocytes: Results From 2 Randomized Controlled Trials Using Primaquine for Gametocyte Clearance. J Infect Dis 2017; 216:457-467. [PMID: 28931236 PMCID: PMC5853855 DOI: 10.1093/infdis/jix237] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Background Single low-dose primaquine (PQ) reduces Plasmodium falciparum infectivity before it impacts gametocyte density. Here, we examined the effect of PQ on gametocyte sex ratio as a possible explanation for this early sterilizing effect. Methods Quantitative reverse-transcription polymerase chain reaction assays were developed to quantify female gametocytes (targeting Pfs25 messenger RNA [mRNA]) and male gametocytes (targeting Pf3D7_1469900 mRNA) in 2 randomized trials in Kenya and Mali, comparing dihydroartemisinin-piperaquine (DP) alone to DP with PQ. Gametocyte sex ratio was examined in relation to time since treatment and infectivity to mosquitoes. Results In Kenya, the median proportion of male gametocytes was 0.33 at baseline. Seven days after treatment, gametocyte density was significantly reduced in the DP-PQ arm relative to the DP arm (females: 0.05% [interquartile range {IQR}, 0.0–0.7%] of baseline; males: 3.4% [IQR, 0.4%–32.9%] of baseline; P < .001). Twenty-four hours after treatment, gametocyte sex ratio became male-biased and was not significantly different between the DP and DP-PQ groups. In Mali, there was no significant difference in sex ratio between the DP and DP-PQ groups (>0.125 mg/kg) 48 hours after treatment, and gametocyte sex ratio was not associated with mosquito infection rates. Conclusions The early sterilizing effects of PQ may not be explained by the preferential clearance of male gametocytes and may be due to an effect on gametocyte fitness.
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Affiliation(s)
- Will Stone
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Patrick Sawa
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Kjerstin Lanke
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sanna Rijpma
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Robin Oriango
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Maureen Nyaurah
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Paul Osodo
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Victor Osoti
- Human Health Division, International Centre for Insect Physiology and Ecology, Mbita Point, Kenya
| | - Almahamoudou Mahamar
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Mali
| | - Halimatou Diawara
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Mali
| | - Rob Woestenenk
- Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Wouter Graumans
- Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - John Bradley
- Medical Research Council Tropical Epidemiology Group, London School of Hygiene and Tropical Medicine, United Kingdom
| | - Ingrid Chen
- Global Health Group, Malaria Elimination Initiative
| | - Joelle Brown
- Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Giulia Siciliano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Istituto Superiore di Sanità, Rome, Italy
| | - Roly Gosling
- Global Health Group, Malaria Elimination Initiative.,Department of Epidemiology and Biostatistics, University of California, San Francisco
| | - Alassane Dicko
- Malaria Research and Training Centre, Faculty of Pharmacy and Faculty of Medicine and Dentistry, University of Science, Techniques and Technologies of Bamako, Mali
| | - Chris Drakeley
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, 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, United Kingdom
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161
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Yeoh LM, Goodman CD, Mollard V, McFadden GI, Ralph SA. Comparative transcriptomics of female and male gametocytes in Plasmodium berghei and the evolution of sex in alveolates. BMC Genomics 2017; 18:734. [PMID: 28923023 PMCID: PMC5604118 DOI: 10.1186/s12864-017-4100-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The clinical symptoms of malaria are caused by the asexual replication of Plasmodium parasites in the blood of the vertebrate host. To spread to new hosts, however, the malaria parasite must differentiate into sexual forms, termed gametocytes, which are ingested by a mosquito vector. Sexual differentiation produces either female or male gametocytes, and involves significant morphological and biochemical changes. These transformations prepare gametocytes for the rapid progression to gamete formation and fertilisation, which occur within 20 min of ingestion. Here we present the transcriptomes of asexual, female, and male gametocytes in P. berghei, and a comprehensive statistically-based differential-expression analysis of the transcriptional changes that underpin this sexual differentiation. RESULTS RNA-seq analysis revealed numerous differences in the transcriptomes of female and male gametocytes compared to asexual stages. Overall, there is net downregulation of transcripts in gametocytes compared to asexual stages, with this trend more marked in female gametocytes. Our analysis identified transcriptional changes in previously-characterised gametocyte-specific pathways, which validated our approach. We also detected many previously-unreported female- and male-specific pathways and genes. Transcriptional biases in stage and gender were then used to investigate sex-specificity and sexual dimorphism of Plasmodium in an evolutionary context. Sex-related gene expression is well conserved between Plasmodium species, but relatively poorly conserved in related organisms outside this genus. This pattern of conservation is most evident in genes necessary for both male and female gametocyte formation. However, this trend is less pronounced for male-specific genes, which are more highly conserved outside the genus than genes specific to female development. CONCLUSIONS We characterised the transcriptional changes that are integral to the development of the female and male sexual forms of Plasmodium. These differential-expression patterns provide a vital insight into understanding the gender-specific characteristics of this essential stage that is the primary target for treatments that block parasite transmission. Our results also offer insight into the evolution of sex genes through Alveolata, and suggest that many Plasmodium sex genes evolved within the genus. We further hypothesise that male gametocytes co-opted pre-existing cellular machinery in their evolutionary history, whereas female gametocytes evolved more through the development of novel, parasite-specific pathways.
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Affiliation(s)
- Lee M Yeoh
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, 3010, Australia.,School of BioSciences, The University of Melbourne, Parkville, 3010, Australia
| | | | - Vanessa Mollard
- School of BioSciences, The University of Melbourne, Parkville, 3010, Australia
| | - Geoffrey I McFadden
- School of BioSciences, The University of Melbourne, Parkville, 3010, Australia.
| | - Stuart A Ralph
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Parkville, 3010, Australia.
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162
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Muñoz EE, Hart KJ, Walker MP, Kennedy MF, Shipley MM, Lindner SE. ALBA4 modulates its stage-specific interactions and specific mRNA fates during Plasmodium yoelii growth and transmission. Mol Microbiol 2017; 106:266-284. [PMID: 28787542 DOI: 10.1111/mmi.13762] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2017] [Indexed: 12/20/2022]
Abstract
Transmission of the malaria parasite occurs in an unpredictable moment, when a mosquito takes a blood meal. Plasmodium has therefore evolved strategies to prepare for transmission, including translationally repressing and protecting mRNAs needed to establish the infection. However, mechanisms underlying these critical controls are not well understood, including whether Plasmodium changes its translationally repressive complexes and mRNA targets in different stages. Efforts to understand this have been stymied by severe technical limitations due to substantial mosquito contamination of samples. Here using P. yoelii, for the first time we provide a proteomic comparison of a protein complex across asexual blood, sexual and sporozoite stages, along with a transcriptomic comparison of the mRNAs that are affected in these stages. We find that the Apicomplexan-specific ALBA4 RNA-binding protein acts to regulate development of the parasite's transmission stages, and that ALBA4 associates with both stage-specific and stage-independent partners to produce opposing mRNA fates. These efforts expand our understanding and ability to interrogate both sexual and sporozoite transmission stages and the molecular preparations they evolved to perpetuate their infectious cycle.
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Affiliation(s)
- Elyse E Muñoz
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
| | - Kevin J Hart
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
| | - Michael P Walker
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
| | - Mark F Kennedy
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
| | - Mackenzie M Shipley
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
| | - Scott E Lindner
- Department of Biochemistry and Molecular Biology, Center for Malaria Research, Pennsylvania State University, University Park, PA, USA
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163
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Proteogenomic analysis of the total and surface-exposed proteomes of Plasmodium vivax salivary gland sporozoites. PLoS Negl Trop Dis 2017; 11:e0005791. [PMID: 28759593 PMCID: PMC5552340 DOI: 10.1371/journal.pntd.0005791] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 08/10/2017] [Accepted: 07/10/2017] [Indexed: 12/29/2022] Open
Abstract
Plasmodium falciparum and Plasmodium vivax cause the majority of human malaria cases. Research efforts predominantly focus on P. falciparum because of the clinical severity of infection and associated mortality rates. However, P. vivax malaria affects more people in a wider global range. Furthermore, unlike P. falciparum, P. vivax can persist in the liver as dormant hypnozoites that can be activated weeks to years after primary infection, causing relapse of symptomatic blood stages. This feature makes P. vivax unique and difficult to eliminate with the standard tools of vector control and treatment of symptomatic blood stage infection with antimalarial drugs. Infection by Plasmodium is initiated by the mosquito-transmitted sporozoite stage, a highly motile invasive cell that targets hepatocytes in the liver. The most advanced malaria vaccine for P. falciparum (RTS,S, a subunit vaccine containing of a portion of the major sporozoite surface protein) conferred limited protection in Phase III trials, falling short of WHO-established vaccine efficacy goals. However, blocking the sporozoite stage of infection in P. vivax, before the establishment of the chronic liver infection, might be an effective malaria vaccine strategy to reduce the occurrence of relapsing blood stages. It is also thought that a multivalent vaccine comprising multiple sporozoite surface antigens will provide better protection, but a comprehensive analysis of proteins in P. vivax sporozoites is not available. To inform sporozoite-based vaccine development, we employed mass spectrometry-based proteomics to identify nearly 2,000 proteins present in P. vivax salivary gland sporozoites. Analysis of protein post-translational modifications revealed extensive phosphorylation of glideosome proteins as well as regulators of transcription and translation. Additionally, the sporozoite surface proteins CSP and TRAP, which were recently discovered to be glycosylated in P. falciparum salivary gland sporozoites, were also observed to be similarly modified in P. vivax sporozoites. Quantitative comparison of the P. vivax and P. falciparum salivary gland sporozoite proteomes revealed a high degree of similarity in protein expression levels, including among invasion-related proteins. Nevertheless, orthologs with significantly different expression levels between the two species could be identified, as well as highly abundant, species-specific proteins with no known orthologs. Finally, we employed chemical labeling of live sporozoites to isolate and identify 36 proteins that are putatively surface-exposed on P. vivax salivary gland sporozoites. In addition to identifying conserved sporozoite surface proteins identified by similar analyses of other Plasmodium species, our analysis identified several as-yet uncharacterized proteins, including a putative 6-Cys protein with no known ortholog in P. falciparum. Malaria is one of the most important infectious diseases in the world with hundreds of millions of new cases every year. Malaria is caused by parasites of the genus Plasmodium which have a complex life cycle, alternating between mosquito and mammalian hosts. Human infections are initiated with a sporozoite inoculum deposited into the skin by parasite-infected mosquitoes as they probe for blood. Sporozoites must locate blood vessels and enter the circulation to reach the liver where they invade and grow in hepatocytes. In the case of Plasmodium vivax, one of the two Plasmodium species responsible for the majority of the disease burden in the world, the parasite has the ability to persist for months in the liver after the initial infection and its activation causes the recurring appearance of the parasite in the blood. Though all clinical symptoms are attributable to the blood stages, it is only by attacking the transmission stages before the formation of hypnozoites (the persisting parasites in the liver) that an impact on the burden of vivax malaria can be achieved. We used state-of-the-art mass spectrometry-based proteomics tools to identify the total protein make-up of P. vivax sporozoites. By analyzing which proteins are exposed to the parasite surface and determining the degree of protein’s post-translational modifications, our investigation will aid the understanding of the novel biology of sporozoites and importantly, advise the development of potential vaccine candidates targeting this parasite stage.
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164
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Ngwa CJ, Kiesow MJ, Papst O, Orchard LM, Filarsky M, Rosinski AN, Voss TS, Llinás M, Pradel G. Transcriptional Profiling Defines Histone Acetylation as a Regulator of Gene Expression during Human-to-Mosquito Transmission of the Malaria Parasite Plasmodium falciparum. Front Cell Infect Microbiol 2017; 7:320. [PMID: 28791254 PMCID: PMC5522858 DOI: 10.3389/fcimb.2017.00320] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/28/2017] [Indexed: 12/16/2022] Open
Abstract
Transmission of the malaria parasite Plasmodium falciparum from the human to the mosquito is mediated by the intraerythrocytic gametocytes, which, once taken up during a blood meal, become activated to initiate sexual reproduction. Because gametocytes are the only parasite stages able to establish an infection in the mosquito, they are crucial for spreading the tropical disease. During gametocyte maturation, different repertoires of genes are switched on and off in a well-coordinated sequence, pointing to regulatory mechanisms of gene expression. While epigenetic gene control has been studied during erythrocytic schizogony of P. falciparum, little is known about this process during human-to-mosquito transmission of the parasite. To unveil the potential role of histone acetylation during gene expression in gametocytes, we carried out a microarray-based transcriptome analysis on gametocytes treated with the histone deacetylase inhibitor trichostatin A (TSA). TSA-treatment impaired gametocyte maturation and lead to histone hyper-acetylation in these stages. Comparative transcriptomics identified 294 transcripts, which were more than 2-fold up-regulated during gametocytogenesis following TSA-treatment. In activated gametocytes, which were less sensitive to TSA, the transcript levels of 48 genes were increased. TSA-treatment further led to repression of ~145 genes in immature and mature gametocytes and 7 genes in activated gametocytes. Up-regulated genes are mainly associated with functions in invasion, cytoadherence, and protein export, while down-regulated genes could particularly be assigned to transcription and translation. Chromatin immunoprecipitation demonstrated a link between gene activation and histone acetylation for selected genes. Among the genes up-regulated in TSA-treated mature gametocytes was a gene encoding the ring finger (RING)-domain protein PfRNF1, a putative E3 ligase of the ubiquitin-mediated signaling pathway. Immunochemistry demonstrated PfRNF1 expression mainly in the sexual stages of P. falciparum with peak expression in stage II gametocytes, where the protein localized to the nucleus and cytoplasm. Pfrnf1 promoter and coding regions associated with acetylated histones, and TSA-treatment resulted in increased PfRNF1 levels. Our combined data point to an essential role of histone acetylation for gene regulation in gametocytes, which can be exploited for malaria transmission-blocking interventions.
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Affiliation(s)
- Che J Ngwa
- Division of Cellular and Applied Infection Biology, RWTH Aachen UniversityAachen, Germany
| | - Meike J Kiesow
- Division of Cellular and Applied Infection Biology, RWTH Aachen UniversityAachen, Germany
| | - Olga Papst
- Division of Cellular and Applied Infection Biology, RWTH Aachen UniversityAachen, Germany
| | - Lindsey M Orchard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, United States
| | - Michael Filarsky
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health InstituteBasel, Switzerland
| | - Alina N Rosinski
- Division of Cellular and Applied Infection Biology, RWTH Aachen UniversityAachen, Germany
| | - Till S Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health InstituteBasel, Switzerland
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, The Pennsylvania State UniversityUniversity Park, PA, United States.,Department of Chemistry and Huck Center for Malaria Research, The Pennsylvania State UniversityUniversity Park, PA, United States
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, RWTH Aachen UniversityAachen, Germany
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165
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Effects of liver-stage clearance by Primaquine on gametocyte carriage of Plasmodium vivax and P. falciparum. PLoS Negl Trop Dis 2017; 11:e0005753. [PMID: 28732068 PMCID: PMC5540608 DOI: 10.1371/journal.pntd.0005753] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 08/02/2017] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Background Primaquine (PQ) is the only currently licensed antimalarial that prevents Plasmodium vivax (Pv) relapses. It also clears mature P. falciparum (Pf) gametocytes, thereby reducing post-treatment transmission. Randomized PQ treatment in a treatment-to-reinfection cohort in Papua New Guinean children permitted the study of Pv and Pf gametocyte carriage after radical cure and to investigate the contribution of Pv relapses. Methods Children received radical cure with Chloroquine, Artemether-Lumefantrine plus either PQ or placebo. Blood samples were subsequently collected in 2-to 4-weekly intervals over 8 months. Gametocytes were detected by quantitative reverse transcription-PCR targeting pvs25 and pfs25. Results PQ treatment reduced the incidence of Pv gametocytes by 73%, which was comparable to the effect of PQ on incidence of blood-stage infections. 92% of Pv and 79% of Pf gametocyte-positive infections were asymptomatic. Pv and to a lesser extent Pf gametocyte positivity and density were associated with high blood-stage parasite densities. Multivariate analysis revealed that the odds of gametocytes were significantly reduced in mixed-species infections compared to single-species infections for both species (ORPv = 0.39 [95% CI 0.25–0.62], ORPf = 0.33 [95% CI 0.18–0.60], p<0.001). No difference between the PQ and placebo treatment arms was observed in density of Pv gametocytes or in the proportion of Pv infections that carried gametocytes. First infections after blood-stage and placebo treatment, likely caused by a relapsing hypnozoite, were equally likely to carry gametocytes than first infections after PQ treatment, likely caused by an infective mosquito bite. Conclusion Pv relapses and new infections are associated with similar levels of gametocytaemia. Relapses thus contribute considerably to the Pv reservoir highlighting the importance of effective anti-hypnozoite treatment for efficient control of Pv. Trial registration ClinicalTrials.gov NCT02143934 Plasmodium vivax (Pv) mainly affects Asia, Central and South America as well as Ethiopia. In Papua New Guinea (PNG) Pv prevalence is among the highest worldwide. The biggest challenge for the control of Pv infections is the formation of dormant liver stages, which have the ability to relapse and cause disease even after successful clearance of asexual stages in the blood circulation. Primaquine is the only licensed drug that is able to prevent Pv relapses. A randomized treatment-to-reinfection cohort in Papua New Guinean children permitted permitted the study of Pv and P. falciparum gametocyte carriage after radical cure with Primaquine and to investigate the contribution of Pv relapses to transmission. We found that most gametocyte carriers in this study were detected in asymptomatic infections and that relapses and new infections are associated with similar Pv gametocyte production. These are strong arguments emphasizing the importance of sensitive detection and early treatment of asymptomatic and submicroscopic Plasmodium spp. infections and of anti-hypnozoite treatment for an effective control of Pv.
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166
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Protein Degradation Systems as Antimalarial Therapeutic Targets. Trends Parasitol 2017; 33:731-743. [PMID: 28688800 DOI: 10.1016/j.pt.2017.05.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 05/23/2017] [Accepted: 05/24/2017] [Indexed: 12/11/2022]
Abstract
Artemisinin (ART)-based combination therapies are the most efficacious treatment of uncomplicated Plasmodium falciparum malaria. Alarmingly, P. falciparum strains have acquired resistance to ART across much of Southeast Asia. ART creates widespread protein and lipid damage inside intraerythrocytic parasites, necessitating macromolecule degradation. The proteasome is the main engine of Plasmodium protein degradation. Indeed, proteasome inhibition and ART have shown synergy in ART-resistant parasites. Moreover, ubiquitin modification is associated with altered parasite susceptibility to multiple antimalarials. Targeting the ubiquitin-proteasome system (UPS), therefore, is an attractive avenue to combat drug resistance. Here, we review recent advances leading to specific targeting of the Plasmodium proteasome. We also highlight the potential for targeting other nonproteasomal protein degradation systems as an additional strategy to disrupt protein homeostasis.
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167
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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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168
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Painter HJ, Carrasquilla M, Llinás M. Capturing in vivo RNA transcriptional dynamics from the malaria parasite Plasmodium falciparum. Genome Res 2017; 27:1074-1086. [PMID: 28416533 PMCID: PMC5453321 DOI: 10.1101/gr.217356.116] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 03/22/2017] [Indexed: 12/30/2022]
Abstract
To capture the transcriptional dynamics within proliferating cells, methods to differentiate nascent transcription from preexisting mRNAs are desired. One approach is to label newly synthesized mRNA transcripts in vivo through the incorporation of modified pyrimidines. However, the human malaria parasite, Plasmodium falciparum, is incapable of pyrimidine salvage for mRNA biogenesis. To capture cellular mRNA dynamics during Plasmodium development, we engineered parasites that can salvage pyrimidines through the expression of a single bifunctional yeast fusion gene, cytosine deaminase/uracil phosphoribosyltransferase (FCU). We show that expression of FCU allows for the direct incorporation of thiol-modified pyrimidines into nascent mRNAs. Using developmental stage-specific promoters to express FCU-GFP enables the biosynthetic capture and in-depth analysis of mRNA dynamics from subpopulations of cells undergoing differentiation. We demonstrate the utility of this method by examining the transcriptional dynamics of the sexual gametocyte stage transition, a process that is essential to malaria transmission between hosts. Using the pfs16 gametocyte-specific promoter to express FCU-GFP in 3D7 parasites, we found that sexual stage commitment is governed by transcriptional reprogramming and stabilization of a subset of essential gametocyte transcripts. We also measured mRNA dynamics in F12 gametocyte-deficient parasites and demonstrate that the transcriptional program required for sexual commitment and maturation is initiated but likely aborted due to the absence of the PfAP2-G transcriptional regulator and a lack of gametocyte-specific mRNA stabilization. Biosynthetic labeling of Plasmodium mRNAs is incredibly versatile, can be used to measure transcriptional dynamics at any stage of parasite development, and will allow for future applications to comprehensively measure RNA-protein interactions in the malaria parasite.
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Affiliation(s)
- Heather J Painter
- Department of Biochemistry and Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Manuela Carrasquilla
- Department of Biochemistry and Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park, Pennsylvania 16802, USA.,Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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169
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Quantitative chromatin proteomics reveals a dynamic histone post-translational modification landscape that defines asexual and sexual Plasmodium falciparum parasites. Sci Rep 2017; 7:607. [PMID: 28377601 PMCID: PMC5428830 DOI: 10.1038/s41598-017-00687-7] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 03/08/2017] [Indexed: 01/24/2023] Open
Abstract
Gene expression in Plasmodia integrates post-transcriptional regulation with epigenetic marking of active genomic regions through histone post-translational modifications (PTMs). To generate insights into the importance of histone PTMs to the entire asexual and sexual developmental cycles of the parasite, we used complementary and comparative quantitative chromatin proteomics to identify and functionally characterise histone PTMs in 8 distinct life cycle stages of P. falciparum parasites. ~500 individual histone PTMs were identified of which 106 could be stringently validated. 46 individual histone PTMs and 30 co-existing PTMs were fully quantified with high confidence. Importantly, 15 of these histone PTMs are novel for Plasmodia (e.g. H3K122ac, H3K27me3, H3K56me3). The comparative nature of the data revealed a highly dynamic histone PTM landscape during life cycle development, with a set of histone PTMs (H3K4ac, H3K9me1 and H3K36me2) displaying a unique and conserved abundance profile exclusively during gametocytogenesis (P < 0.001). Euchromatic histone PTMs are abundant during schizogony and late gametocytes; heterochromatic PTMs mark early gametocytes. Collectively, this data provides the most accurate, complete and comparative chromatin proteomic analyses of the entire life cycle development of malaria parasites. A substantial association between histone PTMs and stage-specific transition provides insights into the intricacies characterising Plasmodial developmental biology.
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170
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Siciliano G, Santha Kumar TR, Bona R, Camarda G, Calabretta MM, Cevenini L, Davioud-Charvet E, Becker K, Cara A, Fidock DA, Alano P. A high susceptibility to redox imbalance of the transmissible stages of Plasmodium falciparum revealed with a luciferase-based mature gametocyte assay. Mol Microbiol 2017; 104:306-318. [PMID: 28118506 DOI: 10.1111/mmi.13626] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/17/2017] [Indexed: 12/18/2022]
Abstract
The goal to prevent Plasmodium falciparum transmission from humans to mosquitoes requires the identification of targetable metabolic processes in the mature (stage V) gametocytes, the sexual stages circulating in the bloodstream. This task is complicated by the apparently low metabolism of these cells, which renders them refractory to most antimalarial inhibitors and constrains the development of specific and sensitive cell-based assays. Here, we identify and functionally characterize the regulatory regions of the P. falciparum gene PF3D7_1234700, encoding a CPW-WPC protein and named here Upregulated in Late Gametocytes (ULG8), which we have leveraged to express reporter genes in mature male and female gametocytes. Using transgenic parasites containing a pfULG8-luciferase cassette, we investigated the susceptibility of stage V gametocytes to compounds specifically affecting redox metabolism. Our results reveal a high sensitivity of mature gametocytes to the glutathione reductase inhibitor and redox cycler drug methylene blue (MB). Using isobologram analysis, we find that a concomitant inhibition of the parasite enzyme glucose-6-phosphate dehydrogenase-6-phosphogluconolactonase, a key component of NADPH synthesis, potently synergizes MB activity. These data suggest that redox metabolism and detoxification activity play an unsuspected yet vital role in stage V gametocytes, rendering these cells exquisitely sensitive to decreases in NADPH concentration.
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Affiliation(s)
- Giulia Siciliano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | - T R Santha Kumar
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA
| | - Roberta Bona
- Dipartimento Farmaco, Istituto Superiore di Sanità, Rome, Italy
| | - Grazia Camarda
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
| | | | - Luca Cevenini
- Department of Chemistry "G. Ciamician", University of Bologna, Bologna, Italy
| | - Elisabeth Davioud-Charvet
- European School of Chemistry, Polymers and Materials (ECPM), UMR 7509 Centre National de la Recherche Scientifique and University of Strasbourg, Strasbourg, France
| | - Katja Becker
- Biochemistry and Molecular Biology, Interdisciplinary Research Center, Justus Liebig University Giessen, Germany
| | - Andrea Cara
- Dipartimento Farmaco, Istituto Superiore di Sanità, Rome, Italy
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, New York, NY, USA.,Division of Infectious Diseases, Department of Medicine, Columbia University Medical Center, New York, NY, USA
| | - Pietro Alano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Rome, Italy
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171
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Miao J, Chen Z, Wang Z, Shrestha S, Li X, Li R, Cui L. Sex-Specific Biology of the Human Malaria Parasite Revealed from the Proteomes of Mature Male and Female Gametocytes. Mol Cell Proteomics 2017; 16:537-551. [PMID: 28126901 DOI: 10.1074/mcp.m116.061804] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2016] [Revised: 12/08/2016] [Indexed: 11/06/2022] Open
Abstract
The gametocytes of the malaria parasites are obligate for perpetuating the parasite's life cycle through mosquitoes, but the sex-specific biology of gametocytes is poorly understood. We generated a transgenic line in the human malaria parasite Plasmodium falciparum, which allowed us to accurately separate male and female gametocytes by flow cytometry. In-depth analysis of the proteomes by liquid chromatography-tandem mass spectrometry identified 1244 and 1387 proteins in mature male and female gametocytes, respectively. GFP-tagging of nine selected proteins confirmed their sex-partitions to be agreeable with the results from the proteomic analysis. The sex-specific proteomes showed significant differences that are consistent with the divergent functions of the two sexes. Although the male-specific proteome (119 proteins) is enriched in proteins associated with the flagella and genome replication, the female-specific proteome (262 proteins) is more abundant in proteins involved in metabolism, translation and organellar functions. Compared with the Plasmodium berghei sex-specific proteomes, this study revealed both extensive conservation and considerable divergence between these two species, which reflect the disparities between the two species in proteins involved in cytoskeleton, lipid metabolism and protein degradation. Comparison with three sex-specific proteomes allowed us to obtain high-confidence lists of 73 and 89 core male- and female-specific/biased proteins conserved in Plasmodium The identification of sex-specific/biased proteomes in Plasmodium lays a solid foundation for understanding the molecular mechanisms underlying the unique sex-specific biology in this early-branching eukaryote.
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Affiliation(s)
- Jun Miao
- From the ‡Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16802;
| | - Zhao Chen
- §Department of Statistics, The Pennsylvania State University, 413 Thomas Building, University Park, Pennsylvania 16802
| | - Zenglei Wang
- From the ‡Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16802
| | - Sony Shrestha
- From the ‡Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16802
| | - Xiaolian Li
- From the ‡Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16802
| | - Runze Li
- §Department of Statistics, The Pennsylvania State University, 413 Thomas Building, University Park, Pennsylvania 16802
| | - Liwang Cui
- From the ‡Department of Entomology, The Pennsylvania State University, 501 ASI Building, University Park, Pennsylvania 16802;
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172
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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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173
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Abstract
Malaria continues to impose a significant disease burden on low- and middle-income countries in the tropics. However, revolutionary progress over the last 3 years in nucleic acid sequencing, reverse genetics, and post-genome analyses has generated step changes in our understanding of malaria parasite (Plasmodium spp.) biology and its interactions with its host and vector. Driven by the availability of vast amounts of genome sequence data from Plasmodium species strains, relevant human populations of different ethnicities, and mosquito vectors, researchers can consider any biological component of the malarial process in isolation or in the interactive setting that is infection. In particular, considerable progress has been made in the area of population genomics, with Plasmodium falciparum serving as a highly relevant model. Such studies have demonstrated that genome evolution under strong selective pressure can be detected. These data, combined with reverse genetics, have enabled the identification of the region of the P. falciparum genome that is under selective pressure and the confirmation of the functionality of the mutations in the kelch13 gene that accompany resistance to the major frontline antimalarial, artemisinin. Furthermore, the central role of epigenetic regulation of gene expression and antigenic variation and developmental fate in P. falciparum is becoming ever clearer. This review summarizes recent exciting discoveries that genome technologies have enabled in malaria research and highlights some of their applications to healthcare. The knowledge gained will help to develop surveillance approaches for the emergence or spread of drug resistance and to identify new targets for the development of antimalarial drugs and perhaps vaccines.
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Affiliation(s)
- Sebastian Kirchner
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - B Joanne Power
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Andrew P Waters
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.
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174
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Suárez-Cortés P, Sharma V, Bertuccini L, Costa G, Bannerman NL, Sannella AR, Williamson K, Klemba M, Levashina EA, Lasonder E, Alano P. Comparative Proteomics and Functional Analysis Reveal a Role of Plasmodium falciparum Osmiophilic Bodies in Malaria Parasite Transmission. Mol Cell Proteomics 2016; 15:3243-3255. [PMID: 27432909 DOI: 10.1074/mcp.m116.060681] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/06/2022] Open
Abstract
An essential step in the transmission of the malaria parasite to the Anopheles vector is the transformation of the mature gametocytes into gametes in the mosquito gut, where they egress from the erythrocytes and mate to produce a zygote, which matures into a motile ookinete. Osmiophilic bodies are electron dense secretory organelles of the female gametocytes which discharge their contents during gamete formation, suggestive of a role in gamete egress. Only one protein with no functional annotation, Pfg377, is described to specifically reside in osmiophilic bodies in Plasmodium falciparum Importantly, Pfg377 defective gametocytes lack osmiophilic bodies and fail to infect mosquitoes, as confirmed here with newly produced pfg377 disrupted parasites. The unique feature of Pfg377 defective gametocytes of lacking osmiophilic bodies was here exploited to perform comparative, label free, global and affinity proteomics analyses of mutant and wild type gametocytes to identify components of these organelles. Subcellular localization studies with fluorescent reporter gene fusions and specific antibodies revealed an osmiophilic body localization for four out of five candidate gene products analyzed: the proteases PfSUB2 (subtilisin 2) and PfDPAP2 (Dipeptidyl aminopeptidase 2), the ortholog of the osmiophilic body component of the rodent malaria gametocytes PbGEST and a previously nonannotated 13 kDa protein. These results establish that osmiophilic bodies and their components are dispensable or marginally contribute (PfDPAP2) to gamete egress. Instead, this work reveals a previously unsuspected role of these organelles in P. falciparum development in the mosquito vector.
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Affiliation(s)
- Pablo Suárez-Cortés
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Vikram Sharma
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Lucia Bertuccini
- ¶Dipartimento Tecnologie e Salute, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Giulia Costa
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Naa-Lamiley Bannerman
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Anna Rosa Sannella
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy
| | - Kim Williamson
- **Department of Biology, Loyola University, 1032 West Sheridan Road, Chicago, Illinois 60660
| | - Michael Klemba
- ‡‡Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
| | - Elena A Levashina
- ‖Department of Vector Biology, Max-Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Edwin Lasonder
- §School of Biomedical and Healthcare Sciences, Plymouth University, Drake Circus, Plymouth, Devon, UK
| | - Pietro Alano
- From the ‡Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena n.299, 00161 Roma, Italy;
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