1
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Omoda A, Matsumoto K, Yoshino KI, Tachibana M, Tsuboi T, Torii M, Ishino T, Iriko H. Skeleton binding protein 1 localizes to the Maurer's cleft and interacts with PfHSP70-1 and PfHSP70-x in Plasmodium falciparum gametocyte-infected erythrocytes. Parasitol Int 2024; 100:102864. [PMID: 38331312 DOI: 10.1016/j.parint.2024.102864] [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: 12/28/2023] [Revised: 02/01/2024] [Accepted: 02/03/2024] [Indexed: 02/10/2024]
Abstract
Plasmodium falciparum accounts for the majority of malaria deaths, due to pathology provoked by the ability of infected erythrocytes to adhere to vascular endothelium within deep tissues. The parasite recognizes endothelium by trafficking and displaying protein ligands on the surface of asexual stage infected erythrocytes, such as members of the large family of pathogenic proteins, P. falciparum erythrocyte membrane protein 1 (PfEMP1). Parasite-encoded skeleton binding protein 1 (SBP1) plays an important role in the transport of these binding-related surface proteins, via cleft-like membranous structures termed Maurer's clefts, which are present within the cytoplasm of infected erythrocytes. Erythrocytes infected with gametocyte stages accumulate in the extravascular compartment of bone marrow; and it was suggested that their surface-expressed adhesion molecule profile and protein trafficking mechanisms might differ from those in asexual stage parasites. Protein trafficking mechanisms via Maurer's clefts have been well investigated in asexual stage parasite-infected erythrocytes; but little is known regarding the gametocyte stages. In this study, we characterized SBP1 during gametocyte maturation and demonstrated that SBP1 is expressed and localizes to dot-like Maurer's cleft structures in the cytoplasm of gametocyte-infected erythrocytes. Co-immunoprecipitation and mass spectrometry assays indicated that SBP1 interacts with the molecular chaperones PfHSP70-1 and PfHSP70-x. Localization analysis suggested that some PfHSP70-1 and/or PfHSP70-x localize in a dot-like pattern within the cytoplasm of immature gametocyte-infected erythrocytes. These findings suggest that SBP1 may interact with HSP70 chaperones in the infected erythrocyte cytoplasm during the immature gametocyte stages.
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Affiliation(s)
- Ayaka Omoda
- Division of Global Infectious Diseases, Department of Public Health, Graduate School of Health Sciences, Kobe University, Kobe, Hyogo, Japan
| | - Konomi Matsumoto
- Faculty of Health Sciences, Kobe University School of Medicine, Kobe, Hyogo, Japan
| | | | - Mayumi Tachibana
- Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, Japan
| | - Takafumi Tsuboi
- Division of Cell-Free Sciences, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan
| | - Motomi Torii
- Division of Global Infectious Diseases, Department of Public Health, Graduate School of Health Sciences, Kobe University, Kobe, Hyogo, Japan; Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Toon, Ehime, Japan
| | - Tomoko Ishino
- Department of Parasitology and Tropical Medicine, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan
| | - Hideyuki Iriko
- Division of Global Infectious Diseases, Department of Public Health, Graduate School of Health Sciences, Kobe University, Kobe, Hyogo, Japan; Faculty of Health Sciences, Kobe University School of Medicine, Kobe, Hyogo, Japan.
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2
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Min H, Liang X, Wang C, Qin J, Boonhok R, Muneer A, Brashear AM, Li X, Minns AM, Adapa SR, Jiang RHY, Ning G, Cao Y, Lindner SE, Miao J, Cui L. The DEAD-box RNA helicase PfDOZI imposes opposing actions on RNA metabolism in Plasmodium falciparum. Nat Commun 2024; 15:3747. [PMID: 38702310 PMCID: PMC11068891 DOI: 10.1038/s41467-024-48140-4] [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: 02/04/2022] [Accepted: 04/19/2024] [Indexed: 05/06/2024] Open
Abstract
In malaria parasites, the regulation of mRNA translation, storage and degradation during development and life-stage transitions remains largely unknown. Here, we functionally characterized the DEAD-box RNA helicase PfDOZI in P. falciparum. Disruption of pfdozi enhanced asexual proliferation but reduced sexual commitment and impaired gametocyte development. By quantitative transcriptomics, we show that PfDOZI is involved in the regulation of invasion-related genes and sexual stage-specific genes during different developmental stages. PfDOZI predominantly participates in processing body-like mRNPs in schizonts but germ cell granule-like mRNPs in gametocytes to impose opposing actions of degradation and protection on different mRNA targets. We further show the formation of stress granule-like mRNPs during nutritional deprivation, highlighting an essential role of PfDOZI-associated mRNPs in stress response. We demonstrate that PfDOZI participates in distinct mRNPs to maintain mRNA homeostasis in response to life-stage transition and environmental changes by differentially executing post-transcriptional regulation on the target mRNAs.
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Affiliation(s)
- Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Xiaoying Liang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases, Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Junling Qin
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
- Department of Medical Technology, School of Allied Health Sciences, and Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Nakhon Si Thammarat, 80160, Thailand
| | - Azhar Muneer
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
| | - Awtum M Brashear
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA
| | - Allen M Minns
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Swamy Rakesh Adapa
- Center for Global Health and Infectious Diseases, Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Rays H Y Jiang
- Center for Global Health and Infectious Diseases, Department of Global Health, College of Public Health, University of South Florida, Tampa, FL, 33612, USA
| | - Gang Ning
- Electron Microscopy Facility, The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, 16802, USA
| | - Yaming Cao
- Department of Immunology, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning, China
| | - Scott E Lindner
- Department of Biochemistry and Molecular Biology, Huck Center for Malaria Research, Pennsylvania State University, University Park, PA, 16802, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA.
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, 3720 Spectrum Boulevard, Tampa, FL, 33612, USA.
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3
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Greyling N, van der Watt M, Gwarinda H, van Heerden A, Greenhouse B, Leroy D, Niemand J, Birkholtz LM. Genetic complexity alters drug susceptibility of asexual and gametocyte stages of Plasmodium falciparum to antimalarial candidates. Antimicrob Agents Chemother 2024; 68:e0129123. [PMID: 38259087 PMCID: PMC10916389 DOI: 10.1128/aac.01291-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Accepted: 12/06/2023] [Indexed: 01/24/2024] Open
Abstract
Malaria elimination requires interventions able to target both the asexual blood stage (ABS) parasites and transmissible gametocyte stages of Plasmodium falciparum. Lead antimalarial candidates are evaluated against clinical isolates to address key concerns regarding efficacy and to confirm that the current, circulating parasites from endemic regions lack resistance against these candidates. While this has largely been performed on ABS parasites, limited data are available on the transmission-blocking efficacy of compounds with multistage activity. Here, we evaluated the efficacy of lead antimalarial candidates against both ABS parasites and late-stage gametocytes side-by-side, against clinical P. falciparum isolates from southern Africa. We additionally correlated drug efficacy to the genetic diversity of the clinical isolates as determined with a panel of well-characterized, genome-spanning microsatellite markers. Our data indicate varying sensitivities of the isolates to key antimalarial candidates, both for ABS parasites and gametocyte stages. While ABS parasites were efficiently killed, irrespective of genetic complexity, antimalarial candidates lost some gametocytocidal efficacy when the gametocytes originated from genetically complex, multiple-clone infections. This suggests a fitness benefit to multiclone isolates to sustain transmission and reduce drug susceptibility. In conclusion, this is the first study to investigate the efficacy of antimalarial candidates on both ABS parasites and gametocytes from P. falciparum clinical isolates where the influence of parasite genetic complexity is highlighted, ultimately aiding the malaria elimination agenda.
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Affiliation(s)
- Nicola Greyling
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Mariëtte van der Watt
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Hazel Gwarinda
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Ashleigh van Heerden
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Bryan Greenhouse
- Department of Medicine, University of California-San Francisco, San Francisco, California, USA
| | - Didier Leroy
- Medicines for Malaria Venture, Geneva, Switzerland
| | - Jandeli Niemand
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
| | - Lyn-Marié Birkholtz
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- Institute for Sustainable Malaria Control, University of Pretoria, Pretoria, South Africa
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4
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Farrukh A, Musabyimana JP, Distler U, Mahlich VJ, Mueller J, Bick F, Tenzer S, Pradel G, Ngwa CJ. The Plasmodium falciparum CCCH zinc finger protein MD3 regulates male gametocytogenesis through its interaction with RNA-binding proteins. Mol Microbiol 2024; 121:543-564. [PMID: 38148574 DOI: 10.1111/mmi.15215] [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: 06/29/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 12/28/2023]
Abstract
The transmission of malaria parasites to mosquitoes is dependent on the formation of gametocytes. Once fully matured, gametocytes are able to transform into gametes in the mosquito's midgut, a process accompanied with their egress from the enveloping erythrocyte. Gametocyte maturation and gametogenesis require a well-coordinated gene expression program that involves a wide spectrum of regulatory proteins, ranging from histone modifiers to transcription factors to RNA-binding proteins. Here, we investigated the role of the CCCH zinc finger protein MD3 in Plasmodium falciparum gametocytogenesis. MD3 was originally identified as an epigenetically regulated protein of immature gametocytes and recently shown to be involved in male development in a barcode-based screen in P. berghei. We report that MD3 is mainly present in the cytoplasm of immature male P. falciparum gametocytes. Parasites deficient of MD3 are impaired in gametocyte maturation and male gametocytogenesis. BioID analysis in combination with co-immunoprecipitation assays unveiled an interaction network of MD3 with RNA-binding proteins like PABP1 and ALBA3, with translational initiators, regulators and repressors like elF4G, PUF1, NOT1 and CITH, and with further regulators of gametocytogenesis, including ZNF4, MD1 and GD1. We conclude that MD3 is part of a regulator complex crucial for post-transcriptional fine-tuning of male gametocytogenesis.
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Affiliation(s)
- Afia Farrukh
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Jean Pierre Musabyimana
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Ute Distler
- Core Facility for Mass Spectrometry, Institute of Immunology, University Medical Centre of the Johannes-Gutenberg University, Mainz, Germany
| | - Vanessa Jil Mahlich
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Julius Mueller
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Fabian Bick
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Stefan Tenzer
- Core Facility for Mass Spectrometry, Institute of Immunology, University Medical Centre of the Johannes-Gutenberg University, Mainz, Germany
| | - Gabriele Pradel
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
| | - Che Julius Ngwa
- Division of Cellular and Applied Infection Biology, Institute of Zoology, RWTH Aachen University, Aachen, Germany
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5
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Kengne-Ouafo JA, Bah SY, Kemp A, Stewart L, Amenga-Etego L, Deitsch KW, Rayner JC, Billker O, Binka FN, Sutherland CJ, Awandare GA, Urban BC, Dinko B. The global transcriptome of Plasmodium falciparum mid-stage gametocytes (stages II-IV) appears largely conserved and gametocyte-specific gene expression patterns vary in clinical isolates. Microbiol Spectr 2023; 11:e0382022. [PMID: 37698406 PMCID: PMC10581088 DOI: 10.1128/spectrum.03820-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 07/09/2023] [Indexed: 09/13/2023] Open
Abstract
Our overall understanding of the developmental biology of malaria parasites has been greatly enhanced by recent advances in transcriptomic analysis. However, most of these investigations rely on laboratory strains (LS) that were adapted into in vitro culture many years ago, and the transcriptomes of clinical isolates (CI) circulating in human populations have not been assessed. In this study, RNA-seq was used to compare the global transcriptome of mid-stage gametocytes derived from three short-term cultured CI, with gametocytes derived from the NF54 reference laboratory strain. The core transcriptome appeared to be consistent between CI- and LS-derived gametocyte preparations, but some important differences were also observed. A majority of gametocyte-specific genes (43/53) appear to have relatively higher expression in CI-derived gametocytes than in LS-derived gametocytes, but a K-means clustering analysis showed that genes involved in flagellum- and microtubule-based processes (movement/motility) were more abundant in both groups, albeit with some differences between them. In addition, gametocytes from one CI described as CI group II gametocytes (CI:GGII) showed gene expression variation in the form of reduced gametocyte-specific gene expression compared to the other two CI-derived gametocytes (CI gametocyte group I, CI:GGI), although the mixed developmental stages used in our study is a potential confounder, only partially mitigated by the inclusion of multiple replicates for each CI. Overall, our study suggests that there may be subtle differences in the gene expression profiles of mid-stage gametocytes from CI relative to the NF54 reference strain of Plasmodium falciparum. Thus, it is necessary to deploy gametocyte-producing clinical parasite isolates to fully understand the diversity of gene expression strategies that may occur during the sequestered development of parasite sexual stages. IMPORTANCE Maturing gametocytes of Plasmodium falciparum are known to sequester away from peripheral circulation into the bone marrow until they are mature. Blocking gametocyte sequestration can prevent malaria transmission from humans to mosquitoes, but most studies aim to understand gametocyte development utilizing long-term adapted laboratory lines instead of clinical isolates. This is a particular issue for our understanding of the sexual stages, which are known to decrease rapidly during adaptation to long-term culture, meaning that many LS are unable to produce transmissible gametocytes. Using RNA-seq, we investigated the global transcriptome of mid-stage gametocytes derived from three clinical isolates and a reference strain (NF54). This identified important differences in gene expression profiles between immature gametocytes of CI and the NF54 reference strain of P. falciparum, suggesting increased investment in gametocytogenesis in clinical isolates. Our transcriptomic data highlight the use of clinical isolates in studying the morphological, cellular features and molecular biology of gametocytes.
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Affiliation(s)
- Jonas A. Kengne-Ouafo
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Saikou Y. Bah
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
- Vaccine and Immunity Theme, MRC Unit The Gambia at London School of Hygiene & Tropical Medicine, Banjul, Gambia
| | - Alison Kemp
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
| | - Lindsay Stewart
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Lucas Amenga-Etego
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York City, New York, USA
| | - Julian C. Rayner
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Oliver Billker
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, United Kingdom
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå University, Umeå, Sweden
| | - Fred N. Binka
- Department of Epidemiology and Biostatistics, School of Public Health, University of Health and Allied Sciences, Ho, Ghana
| | - Colin J. Sutherland
- Department of Infection Biology, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Gordon A. Awandare
- Department of Biochemistry, Cell and Molecular Biology, West African Centre for Cell Biology of Infectious Pathogens, University of Ghana, Accra, Ghana
| | - Britta C. Urban
- Faculty of Biological Sciences, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Bismarck Dinko
- Department of Biomedical Sciences, School of Basic and Biomedical Sciences, University of Health and Allied Sciences, Ho, Ghana
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6
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Shrestha S, Lucky AB, Brashear AM, Li X, Cui L, Miao J. Distinct Histone Post-translational Modifications during Plasmodium falciparum Gametocyte Development. J Proteome Res 2022; 21:1857-1867. [PMID: 35772009 PMCID: PMC9738646 DOI: 10.1021/acs.jproteome.2c00108] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Histones are the building units of nucleosomes, which constitute chromatin. Histone post-translational modifications (PTMs) play an essential role in epigenetic gene regulation. The Plasmodium falciparum genome encodes canonical and variant histones and a collection of conserved enzymes for histone PTMs and chromatin remodeling. Herein, we profiled the P. falciparum histone PTMs during the development of gametocytes, the obligatory stage for parasite transmission. Mass spectrometric analysis of histones extracted from the early, middle, and late stages of gametocytes identified 457 unique histone peptides with 90 PTMs, of which 50% were novel. The gametocyte histone PTMs display distinct patterns from asexual stages, with many new methylation sites in histones H3 and H3.3 (e.g., K14, K18, and K37). Quantitative analyses revealed a high abundance of acetylation in H3 and H4, mono-methylation of H3/H3.3 K37, and ubiquitination of H3BK112, suggesting that these PTMs play critical roles in gametocytes. Gametocyte histones also showed extensive and unique combinations of PTMs. These data indicate that the parasite harbors distinct transcription regulation mechanisms during gametocyte development and lay the foundation for further characterization of epigenetic regulation in the life cycle of the malaria parasite.
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Affiliation(s)
- Sony Shrestha
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Amuza Byaruhanga Lucky
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Awtum Marie Brashear
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States; Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida 33612, United States
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States; Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida 33612, United States
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7
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Liang X, Boonhok R, Siddiqui FA, Xiao B, Li X, Qin J, Min H, Jiang L, Cui L, Miao J. A Leak-Free Inducible CRISPRi/a System for Gene Functional Studies in Plasmodium falciparum. Microbiol Spectr 2022; 10:e0278221. [PMID: 35510853 PMCID: PMC9241666 DOI: 10.1128/spectrum.02782-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 04/18/2022] [Indexed: 12/16/2022] Open
Abstract
By fusing catalytically dead Cas9 (dCas9) to active domains of histone deacetylase (Sir2a) or acetyltransferase (GCN5), this CRISPR interference/activation (CRISPRi/a) system allows gene regulation at the transcriptional level without causing permanent changes in the parasite genome. However, the constitutive expression of dCas9 poses a challenge for studying essential genes, which may lead to adaptive changes in the parasite, masking the true phenotypes. Here, we developed a leak-free inducible CRISPRi/a system by integrating the DiCre/loxP regulon to allow the expression of dCas9-GCN5/-Sir2a upon transient induction with rapamycin, which allows convenient transcriptional regulation of a gene of interest by introducing a guide RNA targeting its transcription start region. Using eight genes that are either silent or expressed from low to high levels during asexual erythrocytic development, we evaluated the robustness and versatility of this system in the asexual parasites. For most genes analyzed, this inducible CRISPRi/a system led to 1.5- to 3-fold up-or downregulation of the target genes at the mRNA level. Alteration in the expression of PfK13 and PfMYST resulted in altered sensitivities to artemisinin. For autophagy-related protein 18, an essential gene related to artemisinin resistance, a >2-fold up- or downregulation was obtained by inducible CRISPRi/a, leading to growth retardation. For the master regulator of gametocytogenesis, PfAP2-G, a >10-fold increase of the PfAP2-G transcripts was obtained by CRISPRa, resulting in >4-fold higher gametocytemia in the induced parasites. Additionally, inducible CRISPRi/a could also regulate gene expression in gametocytes. This inducible epigenetic regulation system offers a fast way of studying gene functions in Plasmodium falciparum. IMPORTANCE Understanding the fundamental biology of malaria parasites through functional genetic/genomic studies is critical for identifying novel targets for antimalarial development. Conditional knockout/knockdown systems are required to study essential genes in the haploid blood stages of the parasite. In this study, we developed an inducible CRISPRi/a system via the integration of DiCre/loxP. We evaluated the robustness and versatility of this system by activating or repressing eight selected genes and achieved up- and downregulation of the targeted genes located in both the euchromatin and heterochromatin regions. This system offers the malaria research community another tool for functional genetic studies.
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Affiliation(s)
- Xiaoying Liang
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Faiza Amber Siddiqui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Bo Xiao
- Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology and Immunology, Pasteur Institute of Shanghai, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Xiaolian Li
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Junling Qin
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Lubin Jiang
- Unit of Human Parasite Molecular and Cell Biology, Key Laboratory of Molecular Virology and Immunology, Pasteur Institute of Shanghai, Chinese Academy of Sciences, Shanghai, People’s Republic of China
| | - Liwang Cui
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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8
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A transcriptional switch controls sex determination in Plasmodium falciparum. Nature 2022; 612:528-533. [PMID: 36477538 PMCID: PMC9750867 DOI: 10.1038/s41586-022-05509-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 11/01/2022] [Indexed: 12/13/2022]
Abstract
Sexual reproduction and meiotic sex are deeply rooted in the eukaryotic tree of life, but mechanisms determining sex or mating types are extremely varied and are only well characterized in a few model organisms1. In malaria parasites, sexual reproduction coincides with transmission to the vector host. Sex determination is non-genetic, with each haploid parasite capable of producing either a male or a female gametocyte in the human host2. The hierarchy of events and molecular mechanisms that trigger sex determination and maintenance of sexual identity are yet to be elucidated. Here we show that the male development 1 (md1) gene is both necessary and sufficient for male fate determination in the human malaria parasite Plasmodium falciparum. We show that Md1 has a dual function stemming from two separate domains: in sex determination through its N terminus and in male development from its conserved C-terminal LOTUS/OST-HTH domain. We further identify a bistable switch at the md1 locus, which is coupled with sex determination and ensures that the male-determining gene is not expressed in the female lineage. We describe one of only a few known non-genetic mechanisms of sex determination in a eukaryote and highlight Md1 as a potential target for interventions that block malaria transmission.
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9
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Singh S, Santos JM, Orchard LM, Yamada N, van Biljon R, Painter HJ, Mahony S, Llinás M. The PfAP2-G2 transcription factor is a critical regulator of gametocyte maturation. Mol Microbiol 2021; 115:1005-1024. [PMID: 33368818 PMCID: PMC8330521 DOI: 10.1111/mmi.14676] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/22/2020] [Accepted: 12/22/2020] [Indexed: 12/14/2022]
Abstract
Differentiation from asexual blood stages to mature sexual gametocytes is required for the transmission of malaria parasites. Here, we report that the ApiAP2 transcription factor, PfAP2-G2 (PF3D7_1408200) plays a critical role in the maturation of Plasmodium falciparum gametocytes. PfAP2-G2 binds to the promoters of a wide array of genes that are expressed at many stages of the parasite life cycle. Interestingly, we also find binding of PfAP2-G2 within the gene body of almost 3,000 genes, which strongly correlates with the location of H3K36me3 and several other histone modifications as well as Heterochromatin Protein 1 (HP1), suggesting that occupancy of PfAP2-G2 in gene bodies may serve as an alternative regulatory mechanism. Disruption of pfap2-g2 does not impact asexual development, but the majority of sexual parasites are unable to mature beyond stage III gametocytes. The absence of pfap2-g2 leads to overexpression of 28% of the genes bound by PfAP2-G2 and none of the PfAP2-G2 bound genes are downregulated, suggesting that it is a repressor. We also find that PfAP2-G2 interacts with chromatin remodeling proteins, a microrchidia (MORC) protein, and another ApiAP2 protein (PF3D7_1139300). Overall our data demonstrate that PfAP2-G2 establishes an essential gametocyte maturation program in association with other chromatin-related proteins.
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Affiliation(s)
- Suprita Singh
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Joana M. Santos
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Lindsey M. Orchard
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Naomi Yamada
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA 16802
| | - Riëtte van Biljon
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Heather J. Painter
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
| | - Shaun Mahony
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802
| | - Manuel Llinás
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802, Huck Center for Malaria Research, The Pennsylvania State University, University Park, PA, USA 16802
- Center for Eukaryotic Gene Regulation, Department of Biochemistry & Molecular Biology, The Pennsylvania State University, University Park, PA, USA 16802
- Department of Chemistry, The Pennsylvania State University, University Park, PA, USA 16802
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10
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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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11
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Investigation of factors affecting the production of P. falciparum gametocytes in an Indian isolate. 3 Biotech 2021; 11:55. [PMID: 33489674 DOI: 10.1007/s13205-020-02586-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/03/2020] [Indexed: 10/22/2022] Open
Abstract
The fundamental requirement of every gametocytocidal drug screening assay is the sufficient numbers of healthy and viable gametocytes. The number of in vitro gametocytes grossly depends on the genetic capacity of parasites to produce gametocytes and on various environmental factors that are not precisely elucidated. In the present study, we tested multiple environmental factors that are reported, hypothesized, or predicted to influence gametocyte numbers. We observed that hypoxanthine and the use of freshly drawn human blood significantly enhance gametocytemia (p < 0.05) in vitro. However, other tested factors did not significantly affect gametocytemia. The addition of N-acetyl glucosamine to the culture enriched the gametocytes but d-sorbitol (5% v/v) in amounts and duration of incubation tested was unable to do so without negatively affecting the maturity and health of the gametocytes. Although the in vitro gametocyte production depends on the genetic capability of the parasite strain tested, various environmental factors also control the ability of the strain to produce gametocytes up to a certain extent. This is the first study testing the role of various environmental factors that might affect the gametocyte development in a gametocyte producing strain. The results presented herein will help in the optimization of gametocyte production procedures for various gametocytocidal drug screening assays.
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12
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Huang G, Murillo Solano C, Melendez J, Shaw J, Collins J, Banks R, Arshadi AK, Boonhok R, Min H, Miao J, Chakrabarti D, Yuan Y. Synthesis, Structure-Activity Relationship, and Antimalarial Efficacy of 6-Chloro-2-arylvinylquinolines. J Med Chem 2020; 63:11756-11785. [PMID: 32959656 DOI: 10.1021/acs.jmedchem.0c00858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
There is an urgent need to develop new efficacious antimalarials to address the emerging drug-resistant clinical cases. Our previous phenotypic screening identified styrylquinoline UCF501 as a promising antimalarial compound. To optimize UCF501, we herein report a detailed structure-activity relationship study of 2-arylvinylquinolines, leading to the discovery of potent, low nanomolar antiplasmodial compounds against a Plasmodium falciparum CQ-resistant Dd2 strain, with excellent selectivity profiles (resistance index < 1 and selectivity index > 200). Several metabolically stable 2-arylvinylquinolines are identified as fast-acting agents that kill asexual blood-stage parasites at the trophozoite phase, and the most promising compound 24 also demonstrates transmission blocking potential. Additionally, the monophosphate salt of 24 exhibits excellent in vivo antimalarial efficacy in the murine model without noticeable toxicity. Thus, the 2-arylvinylquinolines represent a promising class of antimalarial drug leads.
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Affiliation(s)
- Guang Huang
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
| | - Claribel Murillo Solano
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Joel Melendez
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Justin Shaw
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Jennifer Collins
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Robert Banks
- Research Program Services, University of Central Florida, Orlando, Florida 32816, United States
| | - Arash Keshavarzi Arshadi
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States.,Department of Medical Technology, School of Allied Health Science, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, United States
| | - Debopam Chakrabarti
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, Florida 32826, United States
| | - Yu Yuan
- Department of Chemistry, University of Central Florida, Orlando, Florida 32816, United States
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13
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Huang G, Solano CM, Melendez J, Yu-Alfonzo S, Boonhok R, Min H, Miao J, Chakrabarti D, Yuan Y. Discovery of fast-acting dual-stage antimalarial agents by profiling pyridylvinylquinoline chemical space via copper catalyzed azide-alkyne cycloadditions. Eur J Med Chem 2020; 209:112889. [PMID: 33045660 DOI: 10.1016/j.ejmech.2020.112889] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 09/08/2020] [Accepted: 09/24/2020] [Indexed: 11/18/2022]
Abstract
To identity fast-acting, multistage antimalarial agents, a series of pyridylvinylquinoline-triazole analogues have been synthesized via CuAAC. Most of the compounds display significant inhibitory effect on the drug-resistant malarial Dd2 strain at low submicromolar concentrations. Among the tested analogues, compound 60 is the most potent molecule with an EC50 value of 0.04 ± 0.01 μM. Our current study indicates that compound 60 is a fast-acting antimalarial compound and it demonstrates stage specific action at the trophozoite phase in the P. falciparum asexual life cycle. In addition, compound 60 is active against both early and late stage P. falciparum gametocytes. From a mechanistic perspective, compound 60 shows good activity as an inhibitor of β-hematin formation. Collectively, our findings suggest that fast-acting agent 60 targets dual life stages of the malarial parasites and warrant further investigation of pyridylvinylquinoline hybrids as new antimalarials.
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Affiliation(s)
- Guang Huang
- Department of Chemistry, University of Central Florida, Orlando, FL, 32816, USA
| | - Claribel Murillo Solano
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Joel Melendez
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Sabrina Yu-Alfonzo
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA
| | - Rachasak Boonhok
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA; Department of Medical Technology, School of Allied Health Science, Walailak University, Nakhon Si Thammarat, 80160, Thailand
| | - Hui Min
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Jun Miao
- Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL, 33612, USA
| | - Debopam Chakrabarti
- Division of Molecular Microbiology, Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, 32826, USA.
| | - Yu Yuan
- Department of Chemistry, University of Central Florida, Orlando, FL, 32816, USA.
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14
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Metabolomics profiling reveals new aspects of dolichol biosynthesis in Plasmodium falciparum. Sci Rep 2020; 10:13264. [PMID: 32764679 PMCID: PMC7414040 DOI: 10.1038/s41598-020-70246-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 07/24/2020] [Indexed: 01/27/2023] Open
Abstract
The cis-polyisoprenoid lipids namely polyprenols, dolichols and their derivatives are linear polymers of several isoprene units. In eukaryotes, polyprenols and dolichols are synthesized as a mixture of four or more homologues of different length with one or two predominant species with sizes varying among organisms. Interestingly, co-occurrence of polyprenols and dolichols, i.e. detection of a dolichol along with significant levels of its precursor polyprenol, are unusual in eukaryotic cells. Our metabolomics studies revealed that cis-polyisoprenoids are more diverse in the malaria parasite Plasmodium falciparum than previously postulated as we uncovered active de novo biosynthesis and substantial levels of accumulation of polyprenols and dolichols of 15 to 19 isoprene units. A distinctive polyprenol and dolichol profile both within the intraerythrocytic asexual cycle and between asexual and gametocyte stages was observed suggesting that cis-polyisoprenoid biosynthesis changes throughout parasite’s development. Moreover, we confirmed the presence of an active cis-prenyltransferase (PfCPT) and that dolichol biosynthesis occurs via reduction of the polyprenol to dolichol by an active polyprenol reductase (PfPPRD) in the malaria parasite.
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15
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Reporter lines based on the gexp02 promoter enable early quantification of sexual conversion rates in the malaria parasite Plasmodium falciparum. Sci Rep 2019; 9:14595. [PMID: 31601834 PMCID: PMC6787211 DOI: 10.1038/s41598-019-50768-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 09/16/2019] [Indexed: 12/19/2022] Open
Abstract
Transmission of malaria parasites from humans to mosquito vectors requires that some asexual parasites differentiate into sexual forms termed gametocytes. The balance between proliferation in the same host and conversion into transmission forms can be altered by the conditions of the environment. The ability to accurately measure the rate of sexual conversion under different conditions is essential for research addressing the mechanisms underlying sexual conversion, and to assess the impact of environmental factors. Here we describe new Plasmodium falciparum transgenic lines with genome-integrated constructs in which a fluorescent reporter is expressed under the control of the promoter of the gexp02 gene. Using these parasite lines, we developed a sexual conversion assay that shortens considerably the time needed for an accurate determination of sexual conversion rates, and dispenses the need to add chemicals to inhibit parasite replication. Furthermore, we demonstrate that gexp02 is expressed specifically in sexual parasites, with expression starting as early as the sexual ring stage, which makes it a candidate marker for circulating sexual rings in epidemiological studies.
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16
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Valenciano AL, Fernández-Murga ML, Merino EF, Holderman NR, Butschek GJ, Shaffer KJ, Tyler PC, Cassera MB. Metabolic dependency of chorismate in Plasmodium falciparum suggests an alternative source for the ubiquinone biosynthesis precursor. Sci Rep 2019; 9:13936. [PMID: 31558748 PMCID: PMC6763611 DOI: 10.1038/s41598-019-50319-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 09/10/2019] [Indexed: 01/17/2023] Open
Abstract
The shikimate pathway, a metabolic pathway absent in humans, is responsible for the production of chorismate, a branch point metabolite. In the malaria parasite, chorismate is postulated to be a direct precursor in the synthesis of p-aminobenzoic acid (folate biosynthesis), p-hydroxybenzoic acid (ubiquinone biosynthesis), menaquinone, and aromatic amino acids. While the potential value of the shikimate pathway as a drug target is debatable, the metabolic dependency of chorismate in P. falciparum remains unclear. Current evidence suggests that the main role of chorismate is folate biosynthesis despite ubiquinone biosynthesis being active and essential in the malaria parasite. Our goal in the present work was to expand our knowledge of the ubiquinone head group biosynthesis and its potential metabolic dependency on chorismate in P. falciparum. We systematically assessed the development of both asexual and sexual stages of P. falciparum in a defined medium in the absence of an exogenous supply of chorismate end-products and present biochemical evidence suggesting that the benzoquinone ring of ubiquinones in this parasite may be synthesized through a yet unidentified route.
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Affiliation(s)
- Ana Lisa Valenciano
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Maria L Fernández-Murga
- Laboratory of Experimental Pathology, Health Research Institute Hospital La Fe, Valencia, 46026, Spain
| | - Emilio F Merino
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Nicole R Holderman
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Grant J Butschek
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States
| | - Karl J Shaffer
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, New Zealand
| | - Peter C Tyler
- The Ferrier Research Institute, Victoria University of Wellington, Lower Hutt, New Zealand
| | - Maria Belen Cassera
- Department of Biochemistry & Molecular Biology, and Center for Tropical and Emerging Global Diseases (CTEGD), University of Georgia, Athens, Georgia, 30602, United States.
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17
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SADEGHI TAFRESHI A, ZAMANI Z, SABBAGHIAN M, KHAVARI-NEJAD RA, ARJMAND M, SADEGHI S, MOHAMMADI M. A Metabolomic Investigation of the Effect of Eosin B on Game-tocyte of Plasmodium falciparum Using 1HNMR Spectroscopy. IRANIAN JOURNAL OF PARASITOLOGY 2019; 14:592-603. [PMID: 32099562 PMCID: PMC7028228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Recently eosin B was shown to have an effect on the asexual stage of Plasmodium falciparum and in this study, its activity against gametocytes and changes in the culture medium metabolites were investigated using an1HNMR-based metabolomics approach. METHODS In the Biochemistry Department of Pasteur Institute of Iran in 2017, parasites were cultured and gametocytogenesis induced by heparin and 5% hematocrit. Sexual stage parasites were tested by eosin B in 90 well plates and IC50 determined using Lactate Dehydrogenase assay. Gametocytes were treated by IC50 dose of eosin B and the medium collected in the two groups: with eosin B and controls and sent for 1HNMR spectroscopy. The spectra were analyzed on MATLAB interface and the altered metabolites in the culture medium and eosin-affected biochemical pathways were identified by Human Metabolome Database and Metabo-analyst website. RESULTS The results revealed eosin B had an effective gametocytocidal activity against P. falciparum. The significant metabolites changed in the medium were thia-mine, Asp, Asn, Tyr, Lys, Ala, Phenylpyruvic acid, NAD+ and lipids. The main pathways identified were aminoacyl-tRNA biosynthesis, Phenylalanine, tyrosine and tryptophan biosynthesis, Alanine, aspartate and glutamate metabolism, Phenylala-nine metabolism, Nicotinate and nicotinamide metabolism, and lysine degradation. CONCLUSION Eosin B exhibited substantial gametocytocidal activity and affected important drug targets in the Plasmodium.
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Affiliation(s)
| | - Zahra ZAMANI
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran,Correspondence
| | - Marjan SABBAGHIAN
- Department of Andrology at Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran
| | | | - Mohammad ARJMAND
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Sedigheh SADEGHI
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
| | - Maryam MOHAMMADI
- Department of Biochemistry, Pasteur Institute of Iran, Tehran, Iran
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18
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Vγ9Vδ2 T cells proliferate in response to phosphoantigens released from erythrocytes infected with asexual and gametocyte stage Plasmodium falciparum. Cell Immunol 2018; 334:11-19. [PMID: 30177348 DOI: 10.1016/j.cellimm.2018.08.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 08/16/2018] [Accepted: 08/20/2018] [Indexed: 01/14/2023]
Abstract
Vγ9Vδ2 T cells, the dominant γδ T cell subset in human peripheral blood, are stimulated by phosphoantigens, of which (E)-4-Hydroxy-3-methyl-but-2-enyl pyrophosphate, is produced in the apicoplast of malaria parasites. Cell-free media from synchronised Plasmodium falciparum asexual ring, trophozoite, and schizont stage-cultures of high purity as well as media from ruptured schizont cultures, all stimulated Vγ9Vδ2 T cell proliferation, as did media from pure gametocyte cultures, whereas media from uninfected erythrocytes cultures did not. The media from ruptured schizont cultures and all the asexual and gametocyte stage cultures contained only background iron levels, suggesting that all erythrocyte haemoglobin is consumed as the parasites develop and supporting that the phosphoantigens were released from intact parasitized erythrocytes. The Vγ9Vδ2 T cell-stimulating agent was not affected by freezing, thawing or heating but was sensitive to phosphatase treatment, confirming its phosphoantigen identity. In summary, phosphoantigens are released from parasitised erythrocytes at all developmental blood stages.
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19
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Wang W, Liu F, Jiang N, Lu H, Yang N, Feng Y, Sang X, Cao Y, Chen Q. Plasmodium TatD-Like DNase Antibodies Blocked Parasite Development in the Mosquito Gut. Front Microbiol 2018; 9:1023. [PMID: 29867907 PMCID: PMC5968200 DOI: 10.3389/fmicb.2018.01023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 04/30/2018] [Indexed: 12/13/2022] Open
Abstract
The TatD-like DNase of Plasmodium species has previously been characterized as a conserved antigen that plays an important role in immune evasion. Here, we found that TatD-like DNase is expressed, apart from the erythrocytic stage, throughout the developmental stages of the parasite in the mosquito vector. Antibodies to the molecule significantly blocked parasites development and transition in the mosquito gut. Further, mice immunized with recombinant TatD-like DNase showed significant resistance to parasite challenge. The antigenicity of the TatD-like antigen in combination with various adjuvants, including Freund's adjuvants, Montanide ISA 51 and 61, Alhydrogel (aluminum hydroxide), and levamisole was investigated. It was found that immunization of the recombinant TatD-like DNase in combination with Montanide ISA 51 induced strong humoral responses that showed significant protection against parasite challenge in a mouse model. The data further support that TatD-like DNase is a functionally important molecule in the whole development cycle of the malaria parasites and a candidate for malaria vaccine development.
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Affiliation(s)
- Wei Wang
- Key Laboratory of Zoonosis, Jilin University, Changchun, China
| | - Fei Liu
- Department of Immunology, China Medical University, Shenyang, China
| | - Ning Jiang
- Key Laboratory of Zoonosis, Shenyang Agricultural University, Shenyang, China
| | - Huijun Lu
- Key Laboratory of Zoonosis, Jilin University, Changchun, China
| | - Na Yang
- Key Laboratory of Zoonosis, Shenyang Agricultural University, Shenyang, China
| | - Ying Feng
- Key Laboratory of Zoonosis, Shenyang Agricultural University, Shenyang, China
| | - Xiaoyu Sang
- Key Laboratory of Zoonosis, Shenyang Agricultural University, Shenyang, China
| | - Yaming Cao
- Department of Immunology, China Medical University, Shenyang, China
| | - Qijun Chen
- Key Laboratory of Zoonosis, Jilin University, Changchun, China.,Key Laboratory of Zoonosis, Shenyang Agricultural University, Shenyang, China
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20
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Vandana, Singh AP, Singh J, Sharma R, Akhter M, Mishra PK, Saxena AK, Dixit R, Rathi B, Katyal A, Pandey KC. Biochemical characterization of unusual cysteine protease of P. falciparum, metacaspase-2 (MCA-2). Mol Biochem Parasitol 2018; 220:28-41. [PMID: 29317266 DOI: 10.1016/j.molbiopara.2018.01.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 02/05/2023]
Abstract
Earlier studies on Plasmodium apoptosis revealed the presence of proteases with caspases like- activity, which are known as "metacaspases". Although this family of cysteine proteases is structurally similar to caspases with Cys-His dyad but their evolutionary significance and functional relevance remains largely unknown. These proteases are considered to be an important target against malaria due to their absence in humans. In this report, we have biochemically characterized metacaspase-2 (PfMCA-2) of P.falciparum. Enzymatic assay showed that PfMCA-2 efficiently cleaved arginine/lysine specific peptide, but not caspase-specific substrate. Consistently, PfMCA-2 activity was sensitive to effector caspases inhibitor, Z-FA-FMK, and mildly inhibited by aprotinin and E-64. However, general caspase inhibitors such as Z-VAD-FMK and Z-DEVD-FMK had no effect on PfMCA-2 activity. Z-FA-FMK inhibits parasite growth with an IC50 value of 2.7 μM along with the notable morphological changes. PfMCA-2 specifically expressed in schizonts and gametocyte stages and there was a notable depletion of PfMCA-2 expression in Z-FA-FMK treated schizonts and gametocytes stages of parasite. Notably, PfMCA-2 cleaves a phylogenetically conserved protein, TSN (Tudor staphylococcal nuclease) and the proteolysis of PfTSN did not occur after treatment with the Z-FA-FMK. The production of large amount of reactive oxygen species in presence of Z-FA-FMK caused oxidative stress which in turn leads to loss of cell viability. The oxidative stress further generates positive feedback for the occurrence of cell death in term of phosphatidylserine externalization and DNA fragmentation in vitro.
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Affiliation(s)
- Vandana
- National Institute of Malaria Research, New Delhi, 110077, India; Dr B. R. Ambedkar Centre for Biomedical Research, Delhi University, New Delhi, 110007, India
| | - Agam P Singh
- National Institute of Immunology, New Delhi, 110067, India
| | - Jitendra Singh
- Faculty of Pharmacy, Jamia Hamdard, New Delhi, 110062, India
| | - Ruby Sharma
- Jawaharlal Nehru University, New Delhi, 110067, India
| | - Mymoona Akhter
- Faculty of Pharmacy, Jamia Hamdard, New Delhi, 110062, India
| | - Pradyumna K Mishra
- National Institute for Research in Environmental Health, Bhopal 462001, India
| | - Ajay K Saxena
- Jawaharlal Nehru University, New Delhi, 110067, India
| | - Rajnikant Dixit
- National Institute of Malaria Research, New Delhi, 110077, India
| | - Brijesh Rathi
- Dept of Chemistry, Hans Raj College, Delhi University, India
| | - Anju Katyal
- Dr B. R. Ambedkar Centre for Biomedical Research, Delhi University, New Delhi, 110007, India
| | - Kailash C Pandey
- National Institute for Research in Environmental Health, Bhopal 462001, India.
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21
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Abdel-Haleem AM, Hefzi H, Mineta K, Gao X, Gojobori T, Palsson BO, Lewis NE, Jamshidi N. Functional interrogation of Plasmodium genus metabolism identifies species- and stage-specific differences in nutrient essentiality and drug targeting. PLoS Comput Biol 2018; 14:e1005895. [PMID: 29300748 PMCID: PMC5771636 DOI: 10.1371/journal.pcbi.1005895] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 01/17/2018] [Accepted: 11/24/2017] [Indexed: 12/17/2022] Open
Abstract
Several antimalarial drugs exist, but differences between life cycle stages among malaria species pose challenges for developing more effective therapies. To understand the diversity among stages and species, we reconstructed genome-scale metabolic models (GeMMs) of metabolism for five life cycle stages and five species of Plasmodium spanning the blood, transmission, and mosquito stages. The stage-specific models of Plasmodium falciparum uncovered stage-dependent changes in central carbon metabolism and predicted potential targets that could affect several life cycle stages. The species-specific models further highlight differences between experimental animal models and the human-infecting species. Comparisons between human- and rodent-infecting species revealed differences in thiamine (vitamin B1), choline, and pantothenate (vitamin B5) metabolism. Thus, we show that genome-scale analysis of multiple stages and species of Plasmodium can prioritize potential drug targets that could be both anti-malarials and transmission blocking agents, in addition to guiding translation from non-human experimental disease models. Malaria kills nearly one-half million people a year and over 1 billion people are at risk of becoming infected by the parasite. Plasmodial infections are difficult to treat for a myriad of reasons, but the ability of the organism to remain latent in hosts and the complex life cycles greatly contributed to the difficulty in treat malaria. Genome-scale metabolic models (GeMMs) enable hierarchical integration of disparate data types into a framework amenable to computational simulations enabling deeper mechanistic insights from high-throughput data measurements. In this study, GeMMs of multiple Plasmodium species are used to study metabolic similarities and differences across the Plasmodium genus. In silico gene-knock out simulations across species and stages uncovered functional metabolic differences between human- and rodent-infecting species as well as across the parasite’s life-cycle stages. These findings may help identify drug regimens that are more effective in targeting human-infecting species across multiple stages of the organism.
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Affiliation(s)
- Alyaa M. Abdel-Haleem
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Centre (CBRC), Thuwal, Saudi Arabia
- King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering (BESE) division, Thuwal, Saudi Arabia
| | - Hooman Hefzi
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States of America
- Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, La Jolla, CA, United States of America
| | - Katsuhiko Mineta
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Centre (CBRC), Thuwal, Saudi Arabia
| | - Xin Gao
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Centre (CBRC), Thuwal, Saudi Arabia
| | - Takashi Gojobori
- King Abdullah University of Science and Technology (KAUST), Computational Bioscience Research Centre (CBRC), Thuwal, Saudi Arabia
| | - Bernhard O. Palsson
- Department of Bioengineering, University of California, San Diego, La Jolla, CA, United States of America
- Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, La Jolla, CA, United States of America
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
| | - Nathan E. Lewis
- Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, La Jolla, CA, United States of America
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, United States of America
| | - Neema Jamshidi
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, CA, United States of America
- Department of Radiological Sciences, University of California, Los Angeles, CA, United States of America
- * E-mail: ,
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22
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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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23
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Kemirembe K, Cabrera M, Cui L. Interactions between tafenoquine and artemisinin-combination therapy partner drug in asexual and sexual stage Plasmodium falciparum. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2017; 7:131-137. [PMID: 28319724 PMCID: PMC5358947 DOI: 10.1016/j.ijpddr.2017.03.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/04/2017] [Accepted: 03/08/2017] [Indexed: 12/18/2022]
Abstract
The 8-aminoquinoline tafenoquine (TFQ), a primaquine derivative, is currently in late-stage clinical development for the radical cure of P. vivax. Here drug interactions between TFQ and chloroquine and six artemisinin-combination therapy (ACT) partner drugs in P. falciparum asexual stages and gametocytes were investigated. TFQ was mostly synergistic with the ACT-partner drugs in asexual parasites regardless of genetic backgrounds. However, at fixed ratios of 1:3, 1:1 and 3:1, TFQ only interacted synergistically with naphthoquine, pyronaridine and piperaquine in gametocytes. This study indicated that TFQ and ACT-partner drugs will likely have increased potency against asexual stages of the malaria parasites, whereas some drugs may interfere with each other against the P. falciparum gametocytes.
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Affiliation(s)
- Karen Kemirembe
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Mynthia Cabrera
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Liwang Cui
- Department of Entomology, The Pennsylvania State University, University Park, PA 16802, USA.
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24
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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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25
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Structural and functional attributes of malaria parasite diadenosine tetraphosphate hydrolase. Sci Rep 2016; 6:19981. [PMID: 26829485 PMCID: PMC4734340 DOI: 10.1038/srep19981] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/15/2015] [Indexed: 11/09/2022] Open
Abstract
Malaria symptoms are driven by periodic multiplication cycles of Plasmodium parasites in human red blood corpuscles (RBCs). Malaria infection still accounts for ~600,000 annual deaths, and hence discovery of both new drug targets and drugs remains vital. In the present study, we have investigated the malaria parasite enzyme diadenosine tetraphosphate (Ap4A) hydrolase that regulates levels of signalling molecules like Ap4A by hydrolyzing them to ATP and AMP. We have tracked the spatial distribution of parasitic Ap4A hydrolase in infected RBCs, and reveal its unusual localization on the infected RBC membrane in subpopulation of infected cells. Interestingly, enzyme activity assays reveal an interaction between Ap4A hydrolase and the parasite growth inhibitor suramin. We also present a high resolution crystal structure of Ap4A hydrolase in apo- and sulphate- bound state, where the sulphate resides in the enzyme active site by mimicking the phosphate of substrates like Ap4A. The unexpected infected erythrocyte localization of the parasitic Ap4A hydrolase hints at a possible role of this enzyme in purinerigic signaling. In addition, atomic structure of Ap4A hydrolase provides insights for selective drug targeting.
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26
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Mokgethi-Morule T, N'Da DD. Cell based assays for anti-Plasmodium activity evaluation. Eur J Pharm Sci 2016; 84:26-36. [PMID: 26776968 DOI: 10.1016/j.ejps.2016.01.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Revised: 12/28/2015] [Accepted: 01/02/2016] [Indexed: 10/22/2022]
Abstract
Malaria remains one of the most common and deadly infectious diseases worldwide. The severity of this global public health challenge is reflected by the approximately 198 million people, who were reportedly infected in 2013 and by the more than 584,000 related deaths in that same year. The rising emergence of drug resistance towards the once effective artemisinin combination therapies (ACTs) has become a serious concern and warrants more robust drug development strategies, with the objective of eradicating malaria infections. The intricate biology and life cycle of Plasmodium parasites complicate the understanding of the disease in such a way that would enhance the development of more effective chemotherapies that would achieve radical clinical cure and that would prevent disease relapse. Phenotypic cell based assays have for long been a valuable approach and involve the screening and analysis of diverse compounds with regards to their activities towards whole Plasmodium parasites in vitro. To achieve the Millennium Development Goal (MDG) of malaria eradication by 2020, new generation drugs that are active against all parasite stages (erythrocytic (blood), exo-erythrocytic (liver stages and gametocytes)) are needed. Significant advances are being made in assay development to overcome some of the practical challenges of assessing drug efficacy, particularly in the liver and transmission stage Plasmodium models. This review discusses primary screening models and the fundamental progress being made in whole cell based efficacy screens of anti-malarial activity. Ongoing challenges and some opportunities for improvements in assay development that would assist in the discovery of effective, safe and affordable drugs for malaria treatments are also discussed.
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Affiliation(s)
- Thabang Mokgethi-Morule
- Drug Design, Centre of Excellence for Pharmaceutical Sciences (PHARMACEN), North-West University, Potchefstroom 2520, South Africa
| | - David D N'Da
- Drug Design, Centre of Excellence for Pharmaceutical Sciences (PHARMACEN), North-West University, Potchefstroom 2520, South Africa.
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27
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A Putative Non-Canonical Ras-Like GTPase from P. falciparum: Chemical Properties and Characterization of the Protein. PLoS One 2015; 10:e0140994. [PMID: 26540393 PMCID: PMC4634863 DOI: 10.1371/journal.pone.0140994] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 10/02/2015] [Indexed: 12/16/2022] Open
Abstract
During its development the malaria parasite P. falciparum has to adapt to various different environmental contexts. Key cellular mechanisms involving G-protein coupled signal transduction chains are assumed to act at these interfaces. Heterotrimeric G-proteins are absent in Plasmodium. We here describe the first cloning and expression of a putative, non-canonical Ras-like G protein (acronym PfG) from Plasmodium. PfG reveals an open reading frame of 2736 bp encoding a protein of 912 amino acids with a theoretical pI of 8.68 and a molecular weight of 108.57 kDa. Transcript levels and expression are significantly increased in the erythrocytic phase in particular during schizont and gametocyte formation. Most notably, PfG has GTP binding capacity and GTPase activity due to an EngA2 domain present in small Ras-like GTPases in a variety of Bacillus species and Mycobacteria. By contrast, plasmodial PfG is divergent from any human alpha-subunit. PfG was expressed in E. coli as a histidine-tagged fusion protein and was stable only for 3.5 hours. Purification was only possible under native conditions by Nickel-chelate chromatography and subsequent separation by Blue Native PAGE. Binding of a fluorescent GTP analogue BODIPY® FL guanosine 5’O-(thiotriphosphate) was determined by fluorescence emission. Mastoparan stimulated GTP binding in the presence of Mg2+. GTPase activity was determined colorimetrically. Activity expressed as absolute fluorescence was 50% higher for the human paralogue than the activity of the parasitic enzyme. The PfG protein is expressed in the erythrocytic stages and binds GTP after immunoprecipitation. Immunofluorescence using specific antiserum suggests that PfG localizes to the parasite cytosol. The current data suggest that the putitative, Ras-like G-protein might be involved in a non-canonical signaling pathway in Plasmodium. Research on the function of PfG with respect to pathogenesis and antimalarial chemotherapy is currently under way.
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28
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Plasmodium falciparum mitochondria import tRNAs along with an active phenylalanyl-tRNA synthetase. Biochem J 2015; 465:459-69. [PMID: 25391660 DOI: 10.1042/bj20140998] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The Plasmodium falciparum protein translation enzymes aminoacyl-tRNA synthetases (aaRSs) are an emergent family of drug targets. The aaRS ensemble catalyses transfer of amino acids to cognate tRNAs, thus providing charged tRNAs for ribosomal consumption. P. falciparum proteome expression relies on a total of 36 aaRSs for the three translationally independent compartments of cytoplasm, apicoplast and mitochondria. In the present study, we show that, of this set of 36, a single genomic copy of mitochondrial phenylalanyl-tRNA synthetase (mFRS) is targeted to the parasite mitochondria, and that the mFRS gene is exclusive to malaria parasites within the apicomplexan phyla. Our protein cellular localization studies based on immunofluorescence data show that, along with mFRS, P. falciparum harbours two more phenylalanyl-tRNA synthetase (FRS) assemblies that are localized to its apicoplast and cytoplasm. The 'extra' mFRS is found in mitochondria of all asexual blood stage parasites and is competent in aminoacylation. We show further that the parasite mitochondria import tRNAs from the cytoplasmic tRNA pool. Hence drug targeting of FRSs presents a unique opportunity to potentially stall protein production in all three parasite translational compartments.
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29
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Wang Z, Liu M, Liang X, Siriwat S, Li X, Chen X, Parker DM, Miao J, Cui L. A flow cytometry-based quantitative drug sensitivity assay for all Plasmodium falciparum gametocyte stages. PLoS One 2014; 9:e93825. [PMID: 24736563 PMCID: PMC3988044 DOI: 10.1371/journal.pone.0093825] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 03/09/2014] [Indexed: 12/16/2022] Open
Abstract
Background Malaria elimination/eradication campaigns emphasize interruption of parasite transmission as a priority strategy. Screening for new drugs and vaccines against gametocytes is therefore urgently needed. However, current methods for sexual stage drug assays, usually performed by counting or via fluorescent markers are either laborious or restricted to a certain stage. Here we describe the use of a transgenic parasite line for assaying drug sensitivity in all gametocyte stages. Methods A transgenic parasite line expressing green fluorescence protein (GFP) under the control of the gametocyte-specific gene α-tubulin II promoter was generated. This parasite line expresses GFP in all gametocyte stages. Using this transgenic line, we developed a flow cytometry-based assay to determine drug sensitivity of all gametocyte stages, and tested the gametocytocidal activities of four antimalarial drugs. Findings This assay proved to be suitable for determining drug sensitivity of all sexual stages and can be automated. A Z’ factor of 0.79±0.02 indicated that this assay could be further optimized for high-throughput screening. The daily sensitivity of gametocytes to three antimalarial drugs (chloroquine, dihydroartemisinin and pyronaridine) showed a drastic decrease from stage III on, whereas it remained relatively steady for primaquine. Conclusions A drug assay was developed to use a single transgenic parasite line for determining drug susceptibility of all gametocyte stages. This assay may be further automated into a high-throughput platform for screening compound libraries against P. falciparum gametocytes.
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Affiliation(s)
- Zenglei Wang
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Min Liu
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Parasitology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P.R. China
| | - Xiaoying Liang
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Salil Siriwat
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Xiaolian Li
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Xiaoguang Chen
- Department of Parasitology, School of Public Health and Tropical Medicine, Southern Medical University, Guangzhou, Guangdong, P.R. China
| | - Daniel M. Parker
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Jun Miao
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (JM); (LC)
| | - Liwang Cui
- Department of Entomology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (JM); (LC)
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