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Gupta A, Gonzalez-Chavez Z, Desai SA. Plasmodium falciparum CLAG Paralogs All Traffic to the Host Membrane but Knockouts Have Distinct Phenotypes. Microorganisms 2024; 12:1172. [PMID: 38930554 PMCID: PMC11205492 DOI: 10.3390/microorganisms12061172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Malaria parasites increase their host erythrocyte's permeability to obtain essential nutrients from plasma and facilitate intracellular growth. In the human Plasmodium falciparum pathogen, this increase is mediated by the plasmodial surface anion channel (PSAC) and has been linked to CLAG3, a protein integral to the host erythrocyte membrane and encoded by a member of the conserved clag multigene family. Whether paralogs encoded by other clag genes also insert at the host membrane is unknown; their contributions to PSAC formation and other roles served are also unexplored. Here, we generated transfectant lines carrying epitope-tagged versions of each CLAG. Each paralog is colocalized with CLAG3, with concordant trafficking via merozoite rhoptries to the host erythrocyte membrane of newly invaded erythrocytes. Each also exists within infected cells in at least two forms: an alkaline-extractable soluble form and a form integral to the host membrane. Like CLAG3, CLAG2 has a variant region cleaved by extracellular proteases, but CLAG8 and CLAG9 are protease resistant. Paralog knockout lines, generated through CRISPR/Cas9 transfection, exhibited uncompromised growth in PGIM, a modified medium with higher physiological nutrient levels; this finding is in marked contrast to a recently reported CLAG3 knockout parasite. CLAG2 and CLAG8 knockout lines exhibited compensatory increases in the transcription of the remaining clags and associated rhoph genes, yielding increased PSAC-mediated uptake for specific solutes. We also report on the distinct transport properties of these knockout lines. Similar membrane topologies at the host membrane are consistent with each CLAG paralog contributing to PSAC, but other roles require further examination.
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Affiliation(s)
| | | | - Sanjay A. Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MA 20852, USA
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2
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Desai SA. Novel Ion Channel Genes in Malaria Parasites. Genes (Basel) 2024; 15:296. [PMID: 38540355 PMCID: PMC10970509 DOI: 10.3390/genes15030296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 02/19/2024] [Accepted: 02/23/2024] [Indexed: 06/14/2024] Open
Abstract
Ion channels serve many cellular functions including ion homeostasis, volume regulation, signaling, nutrient acquisition, and developmental progression. Although the complex life cycles of malaria parasites necessitate ion and solute flux across membranes, the whole-genome sequencing of the human pathogen Plasmodium falciparum revealed remarkably few orthologs of known ion channel genes. Contrasting with this, biochemical studies have implicated the channel-mediated flux of ions and nutritive solutes across several membranes in infected erythrocytes. Here, I review advances in the cellular and molecular biology of ion channels in malaria parasites. These studies have implicated novel parasite genes in the formation of at least two ion channels, with additional ion channels likely present in various membranes and parasite stages. Computational approaches that rely on homology to known channel genes from higher organisms will not be very helpful in identifying the molecular determinants of these activities. Given their unusual properties, novel molecular and structural features, and essential roles in pathogen survival and development, parasite channels should be promising targets for therapy development.
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Affiliation(s)
- Sanjay A Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
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3
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Jabeena CA, Rajavelu A. Histone globular domain epigenetic modifications: The regulators of chromatin dynamics in malaria parasite. Chembiochem 2024; 25:e202300596. [PMID: 38078518 DOI: 10.1002/cbic.202300596] [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: 08/26/2023] [Revised: 12/09/2023] [Indexed: 01/31/2024]
Abstract
Plasmodium species adapt a complex lifecycle with multiple phenotypes to survive inside various cell types of humans and mosquitoes. Stage-specific gene expression in the developmental stages of parasites is tightly controlled in Plasmodium species; however, the underlying mechanisms have yet to be explored. Genome organization and gene expression for each stage of the malaria parasite need to be better characterized. Recent studies indicated that epigenetic modifications of histone proteins play a vital role in chromatin plasticity. Like other eukaryotes, Plasmodium species N-terminal tail modifications form a distinct "histone code," which creates the docking sites for histone reader proteins, including gene activator/repressor complexes, to regulate gene expression. The emerging research findings shed light on various unconventional epigenetic changes in histone proteins' core/globular domain regions, which might contribute to the chromatin organization in different developmental stages of the malaria parasite. The malaria parasite lost many transcription factors during evolution, and it is proposed that the nature of local chromatin structure essentially regulates the stage-specific gene expression. This review highlights recent discoveries of unconventional histone globular domain epigenetic modifications and their functions in regulating chromatin structure dynamics in various developmental stages of malaria parasites.
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Affiliation(s)
- C A Jabeena
- Pathogen Biology Group, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P O, Thiruvananthapuram, Kerala, 695014, India
| | - Arumugam Rajavelu
- Pathogen Biology Group, Rajiv Gandhi Centre for Biotechnology (RGCB), Thycaud P O, Thiruvananthapuram, Kerala, 695014, India
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology, Madras, Chennai, Tamil Nadu, 600 036, India
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4
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Reyser T, Paloque L, Augereau JM, Di Stefano L, Benoit-Vical F. Epigenetic regulation as a therapeutic target in the malaria parasite Plasmodium falciparum. Malar J 2024; 23:44. [PMID: 38347549 PMCID: PMC10863139 DOI: 10.1186/s12936-024-04855-9] [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: 07/28/2023] [Accepted: 01/18/2024] [Indexed: 02/15/2024] Open
Abstract
Over the past thirty years, epigenetic regulation of gene expression has gained increasing interest as it was shown to be implicated in illnesses ranging from cancers to parasitic diseases. In the malaria parasite, epigenetics was shown to be involved in several key steps of the complex life cycle of Plasmodium, among which asexual development and sexual commitment, but also in major biological processes like immune evasion, response to environmental changes or DNA repair. Because epigenetics plays such paramount roles in the Plasmodium parasite, enzymes involved in these regulating pathways represent a reservoir of potential therapeutic targets. This review focuses on epigenetic regulatory processes and their effectors in the malaria parasite, as well as the inhibitors of epigenetic pathways and their potential as new anti-malarial drugs. Such types of drugs could be formidable tools that may contribute to malaria eradication in a context of widespread resistance to conventional anti-malarials.
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Affiliation(s)
- Thibaud Reyser
- LCC-CNRS, Laboratoire de Chimie de Coordination, CNRS, Université de Toulouse, Toulouse, France
- MAAP, Inserm ERL 1289, Team "New Antiplasmodial Molecules and Pharmacological Approaches", Toulouse, France
- Institut de Pharmacologie et de Biologie Structurale, IPBS, CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Lucie Paloque
- LCC-CNRS, Laboratoire de Chimie de Coordination, CNRS, Université de Toulouse, Toulouse, France
- MAAP, Inserm ERL 1289, Team "New Antiplasmodial Molecules and Pharmacological Approaches", Toulouse, France
- Institut de Pharmacologie et de Biologie Structurale, IPBS, CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Jean-Michel Augereau
- LCC-CNRS, Laboratoire de Chimie de Coordination, CNRS, Université de Toulouse, Toulouse, France
- MAAP, Inserm ERL 1289, Team "New Antiplasmodial Molecules and Pharmacological Approaches", Toulouse, France
- Institut de Pharmacologie et de Biologie Structurale, IPBS, CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Luisa Di Stefano
- MCD, Centre de Biologie Intégrative (CBI), CNRS, UPS, Université de Toulouse, Toulouse, France
| | - Françoise Benoit-Vical
- LCC-CNRS, Laboratoire de Chimie de Coordination, CNRS, Université de Toulouse, Toulouse, France.
- MAAP, Inserm ERL 1289, Team "New Antiplasmodial Molecules and Pharmacological Approaches", Toulouse, France.
- Institut de Pharmacologie et de Biologie Structurale, IPBS, CNRS, UPS, Université de Toulouse, Toulouse, France.
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5
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Thompson TA, Chahine Z, Le Roch KG. The role of long noncoding RNAs in malaria parasites. Trends Parasitol 2023; 39:517-531. [PMID: 37121862 DOI: 10.1016/j.pt.2023.03.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/16/2023] [Accepted: 03/18/2023] [Indexed: 05/02/2023]
Abstract
The human malaria parasites, including Plasmodium falciparum, persist as a major cause of global morbidity and mortality. The recent stalling of progress toward malaria elimination substantiates a need for novel interventions. Controlled gene expression is central to the parasite's numerous life cycle transformations and adaptation. With few specific transcription factors (TFs) identified, crucial roles for chromatin states and epigenetics in parasite transcription have become evident. Although many chromatin-modifying enzymes are known, less is known about which factors mediate their impacts on transcriptional variation. Like those of higher eukaryotes, long noncoding RNAs (lncRNAs) have recently been shown to have integral roles in parasite gene regulation. This review aims to summarize recent developments and key findings on the role of lncRNAs in P. falciparum.
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Affiliation(s)
- Trevor A Thompson
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Zeinab Chahine
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, USA.
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6
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Patterns of Heterochromatin Transitions Linked to Changes in the Expression of Plasmodium falciparum Clonally Variant Genes. Microbiol Spectr 2023; 11:e0304922. [PMID: 36515553 PMCID: PMC9927496 DOI: 10.1128/spectrum.03049-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The survival of malaria parasites in the changing human blood environment largely depends on their ability to alter gene expression by epigenetic mechanisms. The active state of Plasmodium falciparum clonally variant genes (CVGs) is associated with euchromatin characterized by the histone mark H3K9ac, whereas the silenced state is characterized by H3K9me3-based heterochromatin. Expression switches are linked to euchromatin-heterochromatin transitions, but these transitions have not been characterized for the majority of CVGs. To define the heterochromatin distribution patterns associated with the alternative transcriptional states of CVGs, we compared H3K9me3 occupancy at a genome-wide level among several parasite subclones of the same genetic background that differed in the transcriptional state of many CVGs. We found that de novo heterochromatin formation or the complete disruption of a heterochromatin domain is a relatively rare event, and for the majority of CVGs, expression switches can be explained by the expansion or retraction of heterochromatin domains. We identified different modalities of heterochromatin changes linked to transcriptional differences, but despite this complexity, heterochromatin distribution patterns generally enable the prediction of the transcriptional state of specific CVGs. We also found that in some subclones, several var genes were simultaneously in an active state. Furthermore, the heterochromatin levels in the putative regulatory region of the gdv1 antisense noncoding RNA, a regulator of sexual commitment, varied between parasite lines with different sexual conversion rates. IMPORTANCE The malaria parasite P. falciparum is responsible for more than half a million deaths every year. P. falciparum clonally variant genes (CVGs) mediate fundamental host-parasite interactions and play a key role in parasite adaptation to fluctuations in the conditions of the human host. The expression of CVGs is regulated at the epigenetic level by changes in the distribution of a type of chromatin called heterochromatin. Here, we describe at a genome-wide level the changes in the heterochromatin distribution associated with the different transcriptional states of CVGs. Our results also reveal a likely role for heterochromatin at a particular locus in determining the parasite investment in transmission to mosquitoes. Additionally, this data set will enable the prediction of the transcriptional state of CVGs from epigenomic data, which is important for the study of parasite adaptation to the conditions of the host in natural malaria infections.
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7
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De Meulenaere K, Prajapati SK, Villasis E, Cuypers B, Kattenberg JH, Kasian B, Laman M, Robinson LJ, Gamboa D, Laukens K, Rosanas-Urgell A. Band 3-mediated Plasmodium vivax invasion is associated with transcriptional variation in PvTRAg genes. Front Cell Infect Microbiol 2022; 12:1011692. [PMID: 36250048 PMCID: PMC9563252 DOI: 10.3389/fcimb.2022.1011692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/09/2022] [Indexed: 11/13/2022] Open
Abstract
The Plasmodium vivax reticulocyte invasion process is still poorly understood, with only a few receptor-ligand interactions identified to date. Individuals with the Southeast Asian ovalocytosis (SAO) phenotype have a deletion in the band 3 protein on the surface of erythrocytes, and are reported to have a lower incidence of clinical P. vivax malaria. Based on this observation, band 3 has been put forward as a receptor for P. vivax invasion, although direct proof is still lacking. In this study, we combined functional ex vivo invasion assays and transcriptome sequencing to uncover a band 3-mediated invasion pathway in P. vivax and potential band 3 ligands. Invasion by P. vivax field isolates was 67%-71% lower in SAO reticulocytes compared with non-SAO reticulocytes. Reticulocyte invasion was decreased by 40% and 27%-31% when blocking with an anti-band 3 polyclonal antibody and a PvTRAg38 peptide, respectively. To identify new band 3 receptor candidates, we mRNA-sequenced schizont-stage isolates used in the invasion assays, and observed high transcriptional variability in multigene and invasion-related families. Transcriptomes of isolates with low or high dependency on band 3 for invasion were compared by differential expression analysis, which produced a list of band 3 ligand candidates with high representation of PvTRAg genes. Our ex vivo invasion assays have demonstrated that band 3 is a P. vivax invasion receptor and confirm previous in vitro studies showing binding between PvTRAg38 and band 3, although the lower and variable inhibition levels observed suggest the involvement of other ligands. By coupling transcriptomes and invasion phenotypes from the same isolates, we identified a list of band 3 ligand candidates, of which the overrepresented PvTRAg genes are the most promising for future research.
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Affiliation(s)
- Katlijn De Meulenaere
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Surendra Kumar Prajapati
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Elizabeth Villasis
- Laboratorio de Malaria, Laboratorios de Investigación y Desarrollo, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Bart Cuypers
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | | | - Bernadine Kasian
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Moses Laman
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
| | - Leanne J. Robinson
- Vector-borne Diseases Unit, Papua New Guinea Institute for Medical Research, Madang, Papua New Guinea
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
- Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
- Health Security and Disease Elimination, Burnet Institute, Melbourne, VIC, Australia
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kris Laukens
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium
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8
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Epigenetic and Epitranscriptomic Gene Regulation in Plasmodium falciparum and How We Can Use It against Malaria. Genes (Basel) 2022; 13:genes13101734. [PMID: 36292619 PMCID: PMC9601349 DOI: 10.3390/genes13101734] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/15/2022] [Accepted: 09/21/2022] [Indexed: 11/16/2022] Open
Abstract
Malaria, caused by Plasmodium parasites, is still one of the biggest global health challenges. P. falciparum is the deadliest species to humans. In this review, we discuss how this parasite develops and adapts to the complex and heterogenous environments of its two hosts thanks to varied chromatin-associated and epigenetic mechanisms. First, one small family of transcription factors, the ApiAP2 proteins, functions as master regulators of spatio-temporal patterns of gene expression through the parasite life cycle. In addition, chromatin plasticity determines variable parasite cell phenotypes that link to parasite growth, virulence and transmission, enabling parasite adaptation within host conditions. In recent years, epitranscriptomics is emerging as a new regulatory layer of gene expression. We present evidence of the variety of tRNA and mRNA modifications that are being characterized in Plasmodium spp., and the dynamic changes in their abundance during parasite development and cell fate. We end up outlining that new biological systems, like the mosquito model, to decipher the unknowns about epigenetic mechanisms in vivo; and novel methodologies, to study the function of RNA modifications; are needed to discover the Achilles heel of the parasite. With this new knowledge, future strategies manipulating the epigenetics and epitranscriptomic machinery of the parasite have the potential of providing new weapons against malaria.
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9
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Stochastic expression of invasion genes in Plasmodium falciparum schizonts. Nat Commun 2022; 13:3004. [PMID: 35637187 PMCID: PMC9151791 DOI: 10.1038/s41467-022-30605-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Genetically identical cells are known to exhibit differential phenotypes in the same environmental conditions. These phenotypic variants are linked to transcriptional stochasticity and have been shown to contribute towards adaptive flexibility of a wide range of unicellular organisms. Here, we investigate transcriptional heterogeneity and stochastic gene expression in Plasmodium falciparum by performing the quasilinear multiple annealing and looping based amplification cycles (MALBAC) based amplification and single cell RNA sequencing of blood stage schizonts. Our data reveals significant transcriptional variations in the schizont stage with a distinct group of highly variable invasion gene transcripts being identified. Moreover, the data reflects several diversification processes including putative developmental “checkpoint”; transcriptomically distinct parasite sub-populations and transcriptional switches in variable gene families (var, rifin, phist). Most of these features of transcriptional variability are preserved in isogenic parasite cell populations (albeit with a lesser amplitude) suggesting a role of epigenetic factors in cell-to-cell transcriptional variations in human malaria parasites. Lastly, we apply quantitative RT-PCR and RNA-FISH approach and confirm stochastic expression of key invasion genes, such as, msp1, msp3, msp7, eba181 and ama1 which represent prime candidates for invasion-blocking vaccines. Genetically identical cells can be phenotypically diverse to allow adaptive flexibility in a given environment. This phenotypic diversity is driven by epigenetic and transcriptional variability. Here, Tripathi et al. perform scRNA-seq of isogenic and non-isogenic Plasmodium falciparum schizont populations to explore transcriptional heterogeneity and stochastic gene expression during the course of development.
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10
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Epigenetics of malaria parasite nutrient uptake, but why? Trends Parasitol 2022; 38:618-628. [PMID: 35641406 PMCID: PMC9283302 DOI: 10.1016/j.pt.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
Abstract
The conserved plasmodial surface anion channel (PSAC) mediates nutrient uptake by bloodstream malaria parasites and is an antimalarial target. This pathogen-associated channel is linked to the clag multigene family, which is variably expanded in Plasmodium spp. Member genes are under complex epigenetic regulation, with the clag3 genes of the human P. falciparum pathogen exhibiting monoallelic transcription and mutually exclusive surface exposure on infected erythrocytes. While other multigene families use monoallelic expression to evade host immunity, the reasons of epigenetic control of clag genes are unclear. I consider existing models and their implications for nutrient acquisition and immune evasion. Understanding the reasons for epigenetic regulation of PSAC-mediated nutrient uptake will help clarify host-pathogen interactions and guide development of therapies resistant to allele switching.
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11
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Kinetic Tracking of Plasmodium falciparum Antigens on Infected Erythrocytes with a Novel Reporter of Protein Insertion and Surface Exposure. mBio 2022; 13:e0040422. [PMID: 35420481 PMCID: PMC9239273 DOI: 10.1128/mbio.00404-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Intracellular malaria parasites export many proteins into their host cell, inserting several into the erythrocyte plasma membrane to enable interactions with their external environment. While static techniques have identified some surface-exposed proteins, other candidates have eluded definitive localization and membrane topology determination. Moreover, both export kinetics and the mechanisms of membrane insertion remain largely unexplored. We introduce Reporter of Insertion and Surface Exposure (RISE), a method for continuous nondestructive tracking of antigen exposure on infected cells. RISE utilizes a small 11-amino acid (aa) HiBit fragment of NanoLuc inserted into a target protein and detects surface exposure through high-affinity complementation to produce luminescence. We tracked the export and surface exposure of CLAG3, a parasite protein linked to nutrient uptake, throughout the Plasmodiumfalciparum cycle in human erythrocytes. Our approach revealed key determinants of trafficking and surface exposure. Removal of a C-terminal transmembrane domain aborted export. Unexpectedly, certain increases in the exposed reporter size improved the luminescence signal, but other changes abolished the surface signal, revealing that both size and charge of the extracellular epitope influence membrane insertion. Marked cell-to-cell variation with larger inserts containing multiple HiBit epitopes suggests complex regulation of CLAG3 insertion at the host membrane. Quantitative, continuous tracking of CLAG3 surface exposure thus reveals multiple factors that determine this protein’s trafficking and insertion at the host erythrocyte membrane. The RISE assay will enable study of surface antigens from divergent intracellular pathogens.
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12
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Pasternak M, Verhoef JMJ, Wong W, Triglia T, Mlodzianoski MJ, Geoghegan N, Evelyn C, Wardak AZ, Rogers K, Cowman AF. RhopH2 and RhopH3 export enables assembly of the RhopH complex on P. falciparum-infected erythrocyte membranes. Commun Biol 2022; 5:333. [PMID: 35393572 PMCID: PMC8989874 DOI: 10.1038/s42003-022-03290-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2021] [Accepted: 03/17/2022] [Indexed: 11/09/2022] Open
Abstract
RhopH complexes consists of Clag3, RhopH2 and RhopH3 and are essential for growth of Plasmodium falciparum inside infected erythrocytes. Proteins are released from rhoptry organelles during merozoite invasion and trafficked to the surface of infected erythrocytes and enable uptake of nutrients. RhopH3, unlike other RhopH proteins, is required for parasite invasion, suggesting some cellular processes RhopH proteins function as single players rather than a complex. We show the RhopH complex has not formed during merozoite invasion. Clag3 is directly released into the host cell cytoplasm, whilst RhopH2 and RhopH3 are released into the nascent parasitophorous vacuole. Export of RhopH2 and RhopH3 from the parasitophorous vacuole into the infected erythrocyte cytoplasm enables assembly of Clag3/RhopH2/RhopH3 complexes and incorporation into the host cell membrane concomitant with activation of nutrient uptake. This suggests compartmentalisation prevents premature channel assembly before intact complex is assembled at the host cell membrane.
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Affiliation(s)
- Michał Pasternak
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia
- Imperial College London, London, SW7 2AZ, UK
| | - Julie M J Verhoef
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Microbiology, Radboudumc Center for Infectious Diseases, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, Netherlands
| | - Wilson Wong
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia
| | - Tony Triglia
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
| | - Michael J Mlodzianoski
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia
| | - Niall Geoghegan
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia
| | - Cindy Evelyn
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
| | - Ahmad Z Wardak
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
| | - Kelly Rogers
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia
| | - Alan F Cowman
- The Walter and Eliza Hall Institute of Medical Research, Parkville, 3052, Victoria, Australia.
- Department of Medical Biology, The University of Melbourne, Parkville, 3052, Victoria, Australia.
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13
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Tintó-Font E, Michel-Todó L, Russell TJ, Casas-Vila N, Conway DJ, Bozdech Z, Llinás M, Cortés A. A heat-shock response regulated by the PfAP2-HS transcription factor protects human malaria parasites from febrile temperatures. Nat Microbiol 2021; 6:1163-1174. [PMID: 34400833 PMCID: PMC8390444 DOI: 10.1038/s41564-021-00940-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 06/22/2021] [Indexed: 02/07/2023]
Abstract
Periodic fever is a characteristic clinical feature of human malaria, but how parasites survive febrile episodes is not known. Although the genomes of Plasmodium species encode a full set of chaperones, they lack the conserved eukaryotic transcription factor HSF1, which activates the expression of chaperones following heat shock. Here, we show that PfAP2-HS, a transcription factor in the ApiAP2 family, regulates the protective heat-shock response in Plasmodium falciparum. PfAP2-HS activates the transcription of hsp70-1 and hsp90 at elevated temperatures. The main binding site of PfAP2-HS in the entire genome coincides with a tandem G-box DNA motif in the hsp70-1 promoter. Engineered parasites lacking PfAP2-HS have reduced heat-shock survival and severe growth defects at 37 °C but not at 35 °C. Parasites lacking PfAP2-HS also have increased sensitivity to imbalances in protein homeostasis (proteostasis) produced by artemisinin, the frontline antimalarial drug, or the proteasome inhibitor epoxomicin. We propose that PfAP2-HS contributes to the maintenance of proteostasis under basal conditions and upregulates specific chaperone-encoding genes at febrile temperatures to protect the parasite against protein damage.
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Affiliation(s)
- Elisabet Tintó-Font
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - Lucas Michel-Todó
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - Timothy J. Russell
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park 16802, PA, USA
| | - Núria Casas-Vila
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - David J. Conway
- Department of Infection Biology, London School of Hygiene and Tropical Medicine, London, WC1E 7HT, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Manuel Llinás
- Department of Biochemistry & Molecular Biology and Huck Center for Malaria Research, Pennsylvania State University, University Park 16802, PA, USA,Department of Chemistry, Pennsylvania State University, University Park 16802, PA, USA
| | - Alfred Cortés
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona 08036, Catalonia, Spain,ICREA, Barcelona 08010, Catalonia, Spain,Correspondence: (Alfred Cortés)
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14
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Expression Patterns of Plasmodium falciparum Clonally Variant Genes at the Onset of a Blood Infection in Malaria-Naive Humans. mBio 2021; 12:e0163621. [PMID: 34340541 PMCID: PMC8406225 DOI: 10.1128/mbio.01636-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Clonally variant genes (CVGs) play fundamental roles in the adaptation of Plasmodium falciparum to fluctuating conditions of the human host. However, their expression patterns under the natural conditions of the blood circulation have been characterized in detail for only a few specific gene families. Here, we provide a detailed characterization of the complete P. falciparum transcriptome across the full intraerythrocytic development cycle (IDC) at the onset of a blood infection in malaria-naive human volunteers. We found that the vast majority of transcriptional differences between parasites obtained from the volunteers and the parental parasite line maintained in culture occurred in CVGs. In particular, we observed a major increase in the transcript levels of most genes of the pfmc-2tm and gbp families and of specific genes of other families, such as phist, hyp10, rif, or stevor, in addition to previously reported changes in var and clag3 gene expression. Increased transcript levels of individual pfmc-2tm, rif, and stevor genes involved activation in small subsets of parasites. Large transcriptional differences correlated with changes in the distribution of heterochromatin, confirming their epigenetic nature. Furthermore, the similar expression of several CVGs between parasites collected at different time points along the blood infection suggests that the epigenetic memory for multiple CVG families is lost during transmission stages, resulting in a reset of their transcriptional state. Finally, the CVG expression patterns observed in a volunteer likely infected by a single sporozoite suggest that new epigenetic patterns are established during liver stages.
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15
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Peculiarities of Plasmodium falciparum Gene Regulation and Chromatin Structure. Int J Mol Sci 2021; 22:ijms22105168. [PMID: 34068393 PMCID: PMC8153576 DOI: 10.3390/ijms22105168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 05/10/2021] [Accepted: 05/10/2021] [Indexed: 12/14/2022] Open
Abstract
The highly complex life cycle of the human malaria parasite, Plasmodium falciparum, is based on an orchestrated and tightly regulated gene expression program. In general, eukaryotic transcription regulation is determined by a combination of sequence-specific transcription factors binding to regulatory DNA elements and the packaging of DNA into chromatin as an additional layer. The accessibility of regulatory DNA elements is controlled by the nucleosome occupancy and changes of their positions by an active process called nucleosome remodeling. These epigenetic mechanisms are poorly explored in P. falciparum. The parasite genome is characterized by an extraordinarily high AT-content and the distinct architecture of functional elements, and chromatin-related proteins also exhibit high sequence divergence compared to other eukaryotes. Together with the distinct biochemical properties of nucleosomes, these features suggest substantial differences in chromatin-dependent regulation. Here, we highlight the peculiarities of epigenetic mechanisms in P. falciparum, addressing chromatin structure and dynamics with respect to their impact on transcriptional control. We focus on the specialized chromatin remodeling enzymes and discuss their essential function in P. falciparum gene regulation.
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16
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Counihan NA, Modak JK, de Koning-Ward TF. How Malaria Parasites Acquire Nutrients From Their Host. Front Cell Dev Biol 2021; 9:649184. [PMID: 33842474 PMCID: PMC8027349 DOI: 10.3389/fcell.2021.649184] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 02/24/2021] [Indexed: 01/01/2023] Open
Abstract
Plasmodium parasites responsible for the disease malaria reside within erythrocytes. Inside this niche host cell, parasites internalize and digest host hemoglobin to source amino acids required for protein production. However, hemoglobin does not contain isoleucine, an amino acid essential for Plasmodium growth, and the parasite cannot synthesize it de novo. The parasite is also more metabolically active than its host cell, and the rate at which some nutrients are consumed exceeds the rate at which they can be taken up by erythrocyte transporters. To overcome these constraints, Plasmodium parasites increase the permeability of the erythrocyte membrane to isoleucine and other low-molecular-weight solutes it requires for growth by forming new permeation pathways (NPPs). In addition to the erythrocyte membrane, host nutrients also need to cross the encasing parasitophorous vacuole membrane (PVM) and the parasite plasma membrane to access the parasite. This review outlines recent advances that have been made in identifying the molecular constituents of the NPPs, the PVM nutrient channel, and the endocytic apparatus that transports host hemoglobin and identifies key knowledge gaps that remain. Importantly, blocking the ability of Plasmodium to source essential nutrients is lethal to the parasite, and thus, components of these key pathways represent potential antimalaria drug targets.
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Affiliation(s)
| | - Joyanta K Modak
- School of Medicine, Deakin University, Waurn Ponds, VIC, Australia
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17
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Schureck MA, Darling JE, Merk A, Shao J, Daggupati G, Srinivasan P, Olinares PDB, Rout MP, Chait BT, Wollenberg K, Subramaniam S, Desai SA. Malaria parasites use a soluble RhopH complex for erythrocyte invasion and an integral form for nutrient uptake. eLife 2021; 10:e65282. [PMID: 33393463 PMCID: PMC7840181 DOI: 10.7554/elife.65282] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/04/2021] [Indexed: 12/12/2022] Open
Abstract
Malaria parasites use the RhopH complex for erythrocyte invasion and channel-mediated nutrient uptake. As the member proteins are unique to Plasmodium spp., how they interact and traffic through subcellular sites to serve these essential functions is unknown. We show that RhopH is synthesized as a soluble complex of CLAG3, RhopH2, and RhopH3 with 1:1:1 stoichiometry. After transfer to a new host cell, the complex crosses a vacuolar membrane surrounding the intracellular parasite and becomes integral to the erythrocyte membrane through a PTEX translocon-dependent process. We present a 2.9 Å single-particle cryo-electron microscopy structure of the trafficking complex, revealing that CLAG3 interacts with the other subunits over large surface areas. This soluble complex is tightly assembled with extensive disulfide bonding and predicted transmembrane helices shielded. We propose a large protein complex stabilized for trafficking but poised for host membrane insertion through large-scale rearrangements, paralleling smaller two-state pore-forming proteins in other organisms.
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Affiliation(s)
- Marc A Schureck
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
| | - Joseph E Darling
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Alan Merk
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, National Institutes of HealthBethesdaUnited States
| | - Jinfeng Shao
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
| | - Geervani Daggupati
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Prakash Srinivasan
- Department of Molecular Microbiology and Immunology, and Johns Hopkins Malaria Institute, Johns Hopkins Bloomberg School of Public HealthBaltimoreUnited States
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller UniversityNew YorkUnited States
| | - Michael P Rout
- Laboratory of Cellular and Structural Biology, The Rockefeller UniversityNew YorkUnited States
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller UniversityNew YorkUnited States
| | - Kurt Wollenberg
- Office of Cyber Infrastructure & Computational Biology, National Institute of Allergy and Infectious Diseases, National Institutes of HealthBethesdaUnited States
| | - Sriram Subramaniam
- Department of Biochemistry and Molecular Biology, University of British ColumbiaVancouverCanada
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of HealthRockvilleUnited States
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18
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Hollin T, Le Roch KG. From Genes to Transcripts, a Tightly Regulated Journey in Plasmodium. Front Cell Infect Microbiol 2020; 10:618454. [PMID: 33425787 PMCID: PMC7793691 DOI: 10.3389/fcimb.2020.618454] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Over the past decade, we have witnessed significant progresses in understanding gene regulation in Apicomplexa including the human malaria parasite, Plasmodium falciparum. This parasite possesses the ability to convert in multiple stages in various hosts, cell types, and environments. Recent findings indicate that P. falciparum is talented at using efficient and complementary molecular mechanisms to ensure a tight control of gene expression at each stage of its life cycle. Here, we review the current understanding on the contribution of the epigenome, atypical transcription factors, and chromatin organization to regulate stage conversion in P. falciparum. The adjustment of these regulatory mechanisms occurring during the progression of the life cycle will be extensively discussed.
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Affiliation(s)
- Thomas Hollin
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, United States
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, CA, United States
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19
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Live-Cell FRET Reveals that Malaria Nutrient Channel Proteins CLAG3 and RhopH2 Remain Associated throughout Their Tortuous Trafficking. mBio 2020; 11:mBio.01354-20. [PMID: 32900800 PMCID: PMC7482060 DOI: 10.1128/mbio.01354-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Malaria parasites increase their host erythrocyte's permeability to various nutrients, fueling intracellular pathogen development and replication. The plasmodial surface anion channel (PSAC) mediates this uptake and is linked to the parasite-encoded RhopH complex, consisting of CLAG3, RhopH2, and RhopH3. While interactions between these subunits are well established, it is not clear whether they remain associated from their synthesis in developing merozoites through erythrocyte invasion and trafficking to the host membrane. Here, we explored protein-protein interactions between RhopH subunits using live-cell imaging and Förster resonance energy transfer (FRET) experiments. Using the green fluorescent protein (GFP) derivatives mCerulean and mVenus, we generated single- and double-tagged parasite lines for fluorescence measurements. While CLAG3-mCerulean served as an efficient FRET donor for RhopH2-mVenus within rhoptry organelles, mCerulean targeted to this organelle via a short signal sequence produced negligible FRET. Upon merozoite egress and reinvasion, these tagged RhopH subunits were deposited into the new host cell's parasitophorous vacuole; these proteins were then exported and trafficked to the erythrocyte membrane, where CLAG3 and RhopH2 remained fully associated. Fluorescence intensity measurements identified stoichiometric increases in exported RhopH protein when erythrocytes are infected with two parasites; whole-cell patch-clamp revealed a concomitant increase in PSAC functional copy number and a dose effect for RhopH contribution to ion and nutrient permeability. These studies establish live-cell FRET imaging in human malaria parasites, reveal that RhopH subunits traffic to their host membrane destination without dissociation, and suggest quantitative contribution to PSAC formation.IMPORTANCE Malaria parasites grow within circulating red blood cells and uptake nutrients through a pore on their host membrane. Here, we used gene editing to tag CLAG3 and RhopH2, two proteins linked to the nutrient pore, with fluorescent markers and tracked these proteins in living infected cells. After their synthesis in mature parasites, imaging showed that both proteins are packaged into membrane-bound rhoptries. When parasites ruptured their host cells and invaded new red blood cells, these proteins were detected within a vacuole around the parasite before they migrated and inserted in the surface membrane of the host cell. Using simultaneous labeling of CLAG3 and RhopH2, we determined that these proteins interact tightly during migration and after surface membrane insertion. Red blood cells infected with two parasites had twice the protein at their surface and a parallel increase in the number of nutrient pores. Our work suggests that these proteins directly facilitate parasite nutrient uptake from human plasma.
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20
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Llorà-Batlle O, Michel-Todó L, Witmer K, Toda H, Fernández-Becerra C, Baum J, Cortés A. Conditional expression of PfAP2-G for controlled massive sexual conversion in Plasmodium falciparum. SCIENCE ADVANCES 2020; 6:eaaz5057. [PMID: 32577509 PMCID: PMC7286680 DOI: 10.1126/sciadv.aaz5057] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Accepted: 04/15/2020] [Indexed: 05/19/2023]
Abstract
Malaria transmission requires that some asexual parasites convert into sexual forms termed gametocytes. The initial stages of sexual development, including sexually committed schizonts and sexual rings, remain poorly characterized, mainly because they are morphologically identical to their asexual counterparts and only a small subset of parasites undergo sexual development. Here, we describe a system for controlled sexual conversion in the human malaria parasite Plasmodium falciparum, based on conditional expression of the PfAP2-G transcription factor. Using this system, ~90 percent of the parasites converted into sexual forms upon induction, enabling the characterization of committed and early sexual stages without further purification. We characterized sexually committed schizonts and sexual rings at the transcriptomic and phenotypic levels, which revealed down-regulation of genes involved in solute transport upon sexual commitment, among other findings. The new inducible lines will facilitate the study of early sexual stages at additional levels, including multiomic characterization and drug susceptibility assays.
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Affiliation(s)
- Oriol Llorà-Batlle
- ISGlobal, Hospital Clinic–Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - Lucas Michel-Todó
- ISGlobal, Hospital Clinic–Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - Kathrin Witmer
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Haruka Toda
- ISGlobal, Hospital Clinic–Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
| | - Carmen Fernández-Becerra
- ISGlobal, Hospital Clinic–Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
- IGTP Institut d’Investigació Germans Trias i Pujol, Badalona 08916, Catalonia, Spain
| | - Jake Baum
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alfred Cortés
- ISGlobal, Hospital Clinic–Universitat de Barcelona, Barcelona 08036, Catalonia, Spain
- ICREA, Barcelona 08010, Catalonia, Spain
- Corresponding author.
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21
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Ruiz JL, Gómez-Díaz E. The second life of Plasmodium in the mosquito host: gene regulation on the move. Brief Funct Genomics 2020; 18:313-357. [PMID: 31058281 DOI: 10.1093/bfgp/elz007] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 03/08/2019] [Accepted: 03/26/2019] [Indexed: 01/08/2023] Open
Abstract
Malaria parasites face dynamically changing environments and strong selective constraints within human and mosquito hosts. To survive such hostile and shifting conditions, Plasmodium switches transcriptional programs during development and has evolved mechanisms to adjust its phenotype through heterogeneous patterns of gene expression. In vitro studies on culture-adapted isolates have served to set the link between chromatin structure and functional gene expression. Yet, experimental evidence is limited to certain stages of the parasite in the vertebrate, i.e. blood, while the precise mechanisms underlying the dynamic regulatory landscapes during development and in the adaptation to within-host conditions remain poorly understood. In this review, we discuss available data on transcriptional and epigenetic regulation in Plasmodium mosquito stages in the context of sporogonic development and phenotypic variation, including both bet-hedging and environmentally triggered direct transcriptional responses. With this, we advocate the mosquito offers an in vivo biological model to investigate the regulatory networks, transcription factors and chromatin-modifying enzymes and their modes of interaction with regulatory sequences, which might be responsible for the plasticity of the Plasmodium genome that dictates stage- and cell type-specific blueprints of gene expression.
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Affiliation(s)
- José L Ruiz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Elena Gómez-Díaz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, Granada, Spain
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22
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Llorà-Batlle O, Tintó-Font E, Cortés A. Transcriptional variation in malaria parasites: why and how. Brief Funct Genomics 2020; 18:329-341. [PMID: 31114839 DOI: 10.1093/bfgp/elz009] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/04/2019] [Accepted: 04/10/2019] [Indexed: 12/24/2022] Open
Abstract
Transcriptional differences enable the generation of alternative phenotypes from the same genome. In malaria parasites, transcriptional plasticity plays a major role in the process of adaptation to fluctuations in the environment. Multiple studies with culture-adapted parasites and field isolates are starting to unravel the different transcriptional alternatives available to Plasmodium falciparum and the underlying molecular mechanisms. Here we discuss how epigenetic variation, directed transcriptional responses and also genetic changes that affect transcript levels can all contribute to transcriptional variation and, ultimately, parasite survival. Some transcriptional changes are driven by stochastic events. These changes can occur spontaneously, resulting in heterogeneity within parasite populations that provides the grounds for adaptation by dynamic natural selection. However, transcriptional changes can also occur in response to external cues. A better understanding of the mechanisms that the parasite has evolved to alter its transcriptome may ultimately contribute to the design of strategies to combat malaria to which the parasite cannot adapt.
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Affiliation(s)
- Oriol Llorà-Batlle
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
| | - Elisabet Tintó-Font
- ISGlobal, Hospital Clínic - Universitat de Barcelona, 08036 Barcelona, Catalonia, Spain
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23
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Witmer K, Fraschka SA, Vlachou D, Bártfai R, Christophides GK. An epigenetic map of malaria parasite development from host to vector. Sci Rep 2020; 10:6354. [PMID: 32286373 PMCID: PMC7156373 DOI: 10.1038/s41598-020-63121-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/24/2020] [Indexed: 12/23/2022] Open
Abstract
The malaria parasite replicates asexually in the red blood cells of its vertebrate host employing epigenetic mechanisms to regulate gene expression in response to changes in its environment. We used chromatin immunoprecipitation followed by sequencing in conjunction with RNA sequencing to create an epigenomic and transcriptomic map of the developmental transition from asexual blood stages to male and female gametocytes and to ookinetes in the rodent malaria parasite Plasmodium berghei. Across the developmental stages examined, heterochromatin protein 1 associates with variantly expressed gene families localised at subtelomeric regions and variant gene expression based on heterochromatic silencing is observed only in some genes. Conversely, the euchromatin mark histone 3 lysine 9 acetylation (H3K9ac) is abundant in non-heterochromatic regions across all developmental stages. H3K9ac presents a distinct pattern of enrichment around the start codon of ribosomal protein genes in all stages but male gametocytes. Additionally, H3K9ac occupancy positively correlates with transcript abundance in all stages but female gametocytes suggesting that transcription in this stage is independent of H3K9ac levels. This finding together with known mRNA repression in female gametocytes suggests a multilayered mechanism operating in female gametocytes in preparation for fertilization and zygote development, coinciding with parasite transition from host to vector.
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Affiliation(s)
- Kathrin Witmer
- Department of Life Sciences, Imperial College London, SW7 2AZ, London, UK.
| | - Sabine A Fraschka
- Department of Molecular Biology, Radboud University, 6525, GA, Nijmegen, The Netherlands.,Institute of Medical Genetics and Applied Genomics, University of Tübingen, 72076, Tübingen, Germany
| | - Dina Vlachou
- Department of Life Sciences, Imperial College London, SW7 2AZ, London, UK
| | - Richárd Bártfai
- Department of Molecular Biology, Radboud University, 6525, GA, Nijmegen, The Netherlands
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24
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Cai FY, DeSimone TM, Hansen E, Jennings CV, Bei AK, Ahouidi AD, Mboup S, Duraisingh MT, Buckee CO. Accounting for red blood cell accessibility reveals distinct invasion strategies in Plasmodium falciparum strains. PLoS Comput Biol 2020; 16:e1007702. [PMID: 32315315 PMCID: PMC7194430 DOI: 10.1371/journal.pcbi.1007702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 05/01/2020] [Accepted: 01/31/2020] [Indexed: 11/19/2022] Open
Abstract
The growth of the malaria parasite Plasmodium falciparum in human blood causes all the symptoms of malaria. To proliferate, non-motile parasites must have access to susceptible red blood cells, which they invade using pairs of parasite ligands and host receptors that define invasion pathways. Parasites can switch invasion pathways, and while this flexibility is thought to facilitate immune evasion, it may also reflect the heterogeneity of red blood cell surfaces within and between hosts. Host genetic background affects red blood cell structure, for example, and red blood cells also undergo dramatic changes in morphology and receptor density as they age. The in vivo consequences of both the accessibility of susceptible cells, and their heterogeneous susceptibility, remain unclear. Here, we measured invasion of laboratory strains of P. falciparum relying on distinct invasion pathways into red blood cells of different ages. We estimated invasion efficiency while accounting for red blood cell accessibility to parasites. This approach revealed different tradeoffs made by parasite strains between the fraction of cells they can invade and their invasion rate into them, and we distinguish "specialist" strains from "generalist" strains in this context. We developed a mathematical model to show that generalist strains would lead to higher peak parasitemias in vivo compared to specialist strains with similar overall proliferation rates. Thus, the ecology of red blood cells may play a key role in determining the rate of P. falciparum parasite proliferation and malaria virulence.
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Affiliation(s)
- Francisco Y. Cai
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Tiffany M. DeSimone
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Elsa Hansen
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Cameron V. Jennings
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Amy K. Bei
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Ambroise D. Ahouidi
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - Souleymane Mboup
- Laboratory of Bacteriology and Virology, Le Dantec Hospital, Cheikh Anta Diop University, Dakar, Senegal
| | - Manoj T. Duraisingh
- Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
| | - Caroline O. Buckee
- Center for Communicable Disease Dynamics, Department of Epidemiology, Harvard TH Chan School of Public Health, Boston, Massachusetts, United States of America
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25
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Gupta A, Bokhari AAB, Pillai AD, Crater AK, Gezelle J, Saggu G, Nasamu AS, Ganesan SM, Niles JC, Desai SA. Complex nutrient channel phenotypes despite Mendelian inheritance in a Plasmodium falciparum genetic cross. PLoS Pathog 2020; 16:e1008363. [PMID: 32069335 PMCID: PMC7048409 DOI: 10.1371/journal.ppat.1008363] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 02/28/2020] [Accepted: 01/28/2020] [Indexed: 12/30/2022] Open
Abstract
Malaria parasites activate a broad-selectivity ion channel on their host erythrocyte membrane to obtain essential nutrients from the bloodstream. This conserved channel, known as the plasmodial surface anion channel (PSAC), has been linked to parasite clag3 genes in P. falciparum, but epigenetic switching between the two copies of this gene hinders clear understanding of how the encoded protein determines PSAC activity. Here, we used linkage analysis in a P. falciparum cross where one parent carries a single clag3 gene to overcome the effects of switching and confirm a primary role of the clag3 product with high confidence. Despite Mendelian inheritance, CLAG3 conditional knockdown revealed remarkably preserved nutrient and solute uptake. Even more surprisingly, transport remained sensitive to a CLAG3 isoform-specific inhibitor despite quantitative knockdown, indicating that low doses of the CLAG3 transgene are sufficient to confer block. We then produced a complete CLAG3 knockout line and found it exhibits an incomplete loss of transport activity, in contrast to rhoph2 and rhoph3, two PSAC-associated genes that cannot be disrupted because nutrient uptake is abolished in their absence. Although the CLAG3 knockout did not incur a fitness cost under standard nutrient-rich culture conditions, this parasite could not be propagated in a modified medium that more closely resembles human plasma. These studies implicate oligomerization of CLAG paralogs encoded by various chromosomes in channel formation. They also reveal that CLAG3 is dispensable under standard in vitro conditions but required for propagation under physiological conditions.
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Affiliation(s)
- Ankit Gupta
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Abdullah A. B. Bokhari
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Ajay D. Pillai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Anna K. Crater
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Jeanine Gezelle
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Gagandeep Saggu
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
| | - Armiyaw S. Nasamu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Suresh M. Ganesan
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Jacquin C. Niles
- Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - Sanjay A. Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, Maryland, United States of America
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26
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Martin RE. The transportome of the malaria parasite. Biol Rev Camb Philos Soc 2019; 95:305-332. [PMID: 31701663 DOI: 10.1111/brv.12565] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/02/2019] [Accepted: 10/04/2019] [Indexed: 12/15/2022]
Abstract
Membrane transport proteins, also known as transporters, control the movement of ions, nutrients, metabolites, and waste products across the membranes of a cell and are central to its biology. Proteins of this type also serve as drug targets and are key players in the phenomenon of drug resistance. The malaria parasite has a relatively reduced transportome, with only approximately 2.5% of its genes encoding transporters. Even so, assigning functions and physiological roles to these proteins, and ascertaining their contributions to drug action and drug resistance, has been very challenging. This review presents a detailed critique and synthesis of the disruption phenotypes, protein subcellular localisations, protein functions (observed or predicted), and links to antimalarial drug resistance for each of the parasite's transporter genes. The breadth and depth of the gene disruption data are particularly impressive, with at least one phenotype determined in the parasite's asexual blood stage for each transporter gene, and multiple phenotypes available for 76% of the genes. Analysis of the curated data set revealed there to be relatively little redundancy in the Plasmodium transportome; almost two-thirds of the parasite's transporter genes are essential or required for normal growth in the asexual blood stage of the parasite, and this proportion increased to 78% when the disruption phenotypes available for the other parasite life stages were included in the analysis. These observations, together with the finding that 22% of the transportome is implicated in the parasite's resistance to existing antimalarials and/or drugs within the development pipeline, indicate that transporters are likely to serve, or are already serving, as drug targets. Integration of the different biological and bioinformatic data sets also enabled the selection of candidates for transport processes known to be essential for parasite survival, but for which the underlying proteins have thus far remained undiscovered. These include potential transporters of pantothenate, isoleucine, or isopentenyl diphosphate, as well as putative anion-selective channels that may serve as the pore component of the parasite's 'new permeation pathways'. Other novel insights into the parasite's biology included the identification of transporters for the potential development of antimalarial treatments, transmission-blocking drugs, prophylactics, and genetically attenuated vaccines. The syntheses presented herein set a foundation for elucidating the functions and physiological roles of key members of the Plasmodium transportome and, ultimately, to explore and realise their potential as therapeutic targets.
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Affiliation(s)
- Rowena E Martin
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, Australia
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27
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Abel S, Le Roch KG. The role of epigenetics and chromatin structure in transcriptional regulation in malaria parasites. Brief Funct Genomics 2019; 18:302-313. [PMID: 31220857 PMCID: PMC6859822 DOI: 10.1093/bfgp/elz005] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 02/25/2019] [Accepted: 03/14/2019] [Indexed: 12/28/2022] Open
Abstract
Due to the unique selective pressures and extreme changes faced by the human malaria parasite Plasmodium falciparum throughout its life cycle, the parasite has evolved distinct features to alter its gene expression patterns. Along with classical gene regulation by transcription factors (TFs), of which only one family, the AP2 TFs, has been described in the parasite genome, a large body of evidence points toward chromatin structure and epigenetic factors mediating the changes in gene expression associated with parasite life cycle stages. These attributes may be critically important for immune evasion, host cell invasion and development of the parasite in its two hosts, the human and the Anopheles vector. Thus, the factors involved in the maintenance and regulation of chromatin and epigenetic features represent potential targets for antimalarial drugs. In this review, we discuss the mechanisms in P. falciparum that regulate chromatin structure, nucleosome landscape, the 3-dimensional structure of the genome and additional distinctive features created by parasite-specific genes and gene families. We review conserved traits of chromatin in eukaryotes in order to highlight what is unique in the parasite.
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Affiliation(s)
- Steven Abel
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, Riverside, CA, USA
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28
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Ruiz JL, Tena JJ, Bancells C, Cortés A, Gómez-Skarmeta JL, Gómez-Díaz E. Characterization of the accessible genome in the human malaria parasite Plasmodium falciparum. Nucleic Acids Res 2019; 46:9414-9431. [PMID: 30016465 PMCID: PMC6182165 DOI: 10.1093/nar/gky643] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 07/10/2018] [Indexed: 12/27/2022] Open
Abstract
Human malaria is a devastating disease and a major cause of poverty in resource-limited countries. To develop and adapt within hosts Plasmodium falciparum undergoes drastic switches in gene expression. To identify regulatory regions in the parasite genome, we performed genome-wide profiling of chromatin accessibility in two culture-adapted isogenic subclones at four developmental stages during the intraerythrocytic cycle by using the Assay for Transposase-Accessible Chromatin by sequencing (ATAC-seq). Tn5 transposase hypersensitivity sites (THSSs) localize preferentially at transcriptional start sites (TSSs). Chromatin accessibility by ATAC-seq is predictive of active transcription and of the levels of histone marks H3K9ac and H3K4me3. Our assay allows the identification of novel regulatory regions including TSS and enhancer-like elements. We show that the dynamics in the accessible chromatin profile matches temporal transcription during development. Motif analysis of stage-specific ATAC-seq sites predicts the in vivo binding sites and function of multiple ApiAP2 transcription factors. At last, the alternative expression states of some clonally variant genes (CVGs), including eba, phist, var and clag genes, associate with a differential ATAC-seq signal at their promoters. Altogether, this study identifies genome-wide regulatory regions likely to play an essential function in the developmental transitions and in CVG expression in P. falciparum.
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Affiliation(s)
- José Luis Ruiz
- Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones Científicas, Seville 41092, Spain
| | - Juan J Tena
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville 41013, Spain
| | - Cristina Bancells
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia 08036, Spain
| | - Alfred Cortés
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia 08036, Spain.,ICREA, Barcelona, Catalonia 08010, Spain
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo (CABD), Consejo Superior de Investigaciones Científicas-Universidad Pablo de Olavide-Junta de Andalucía, Seville 41013, Spain
| | - Elena Gómez-Díaz
- Estación Biológica de Doñana (EBD), Consejo Superior de Investigaciones Científicas, Seville 41092, Spain.,Instituto de Parasitología y Biomedicina 'López-Neyra' (IPBLN), Consejo Superior de Investigaciones Científicas, Granada 18016, Spain
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29
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Chang Z, Yadav V, Lee SC, Heitman J. Epigenetic mechanisms of drug resistance in fungi. Fungal Genet Biol 2019; 132:103253. [PMID: 31325489 DOI: 10.1016/j.fgb.2019.103253] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Revised: 07/12/2019] [Accepted: 07/15/2019] [Indexed: 12/30/2022]
Abstract
The emergence of drug-resistant fungi poses a continuously increasing threat to human health. Despite advances in preventive care and diagnostics, resistant fungi continue to cause significant mortality, especially in immunocompromised patients. Therapeutic resources are further limited by current usage of only four major classes of antifungal drugs. Resistance against these drugs has already been observed in pathogenic fungi requiring the development of much needed newer antifungal drugs. Epigenetic changes such as DNA or chromatin modifications alter gene expression levels in response to certain stimuli, including interaction with the host in the case of fungal pathogens. These changes can confer resistance to drugs by altering the expression of target genes or genes encoding drug efflux pumps. Multiple pathogens share many of these epigenetic pathways; thus, targeting epigenetic pathways might also identify drug target candidates for the development of broad-spectrum antifungal drugs. In this review, we discuss the importance of epigenetic pathways in mediating drug resistance in fungi as well as in the development of anti-fungal drugs.
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Affiliation(s)
- Zanetta Chang
- Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC 27710, USA
| | - Vikas Yadav
- Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC 27710, USA
| | - Soo Chan Lee
- South Texas Center for Emerging Infectious Diseases (STCEID), Department of Biology, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Joseph Heitman
- Department of Molecular Genetics and Microbiology, Duke University, Duke University Medical Center, Durham, NC 27710, USA.
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30
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Identification of Antimalarial Compounds That Require CLAG3 for Their Uptake by Plasmodium falciparum-Infected Erythrocytes. Antimicrob Agents Chemother 2019; 63:AAC.00052-19. [PMID: 30782998 DOI: 10.1128/aac.00052-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 02/01/2019] [Indexed: 01/15/2023] Open
Abstract
During the intraerythrocytic asexual cycle malaria parasites acquire nutrients and other solutes through a broad selectivity channel localized at the membrane of the infected erythrocyte termed the plasmodial surface anion channel (PSAC). The protein product of the Plasmodium falciparum clonally variant clag3.1 and clag3.2 genes determines PSAC activity. Switches in the expression of clag3 genes, which are regulated by epigenetic mechanisms, are associated with changes in PSAC-dependent permeability that can result in resistance to compounds toxic for the parasite, such as blasticidin S. Here, we investigated whether other antimalarial drugs require CLAG3 to reach their intracellular target and consequently are prone to parasite resistance by epigenetic mechanisms. We found that the bis-thiazolium salts T3 (also known as albitiazolium) and T16 require the product of clag3 genes to enter infected erythrocytes. P. falciparum populations can develop resistance to these compounds via the selection of parasites with dramatically reduced expression of both genes. However, other compounds previously demonstrated or predicted to enter infected erythrocytes through transport pathways absent from noninfected erythrocytes, such as fosmidomycin, doxycycline, azithromycin, lumefantrine, or pentamidine, do not require expression of clag3 genes for their antimalarial activity. This suggests that they use alternative CLAG3-independent routes to access parasites. Our results demonstrate that P. falciparum can develop resistance to diverse antimalarial compounds by epigenetic changes in the expression of clag3 genes. This is of concern for drug development efforts because drug resistance by epigenetic mechanisms can arise quickly, even during the course of a single infection.
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Campino S, Marin-Menendez A, Kemp A, Cross N, Drought L, Otto TD, Benavente ED, Ravenhall M, Schwach F, Girling G, Manske M, Theron M, Gould K, Drury E, Clark TG, Kwiatkowski DP, Pance A, Rayner JC. A forward genetic screen reveals a primary role for Plasmodium falciparum Reticulocyte Binding Protein Homologue 2a and 2b in determining alternative erythrocyte invasion pathways. PLoS Pathog 2018; 14:e1007436. [PMID: 30496294 PMCID: PMC6289454 DOI: 10.1371/journal.ppat.1007436] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 12/11/2018] [Accepted: 10/24/2018] [Indexed: 12/14/2022] Open
Abstract
Invasion of human erythrocytes is essential for Plasmodium falciparum parasite survival and pathogenesis, and is also a complex phenotype. While some later steps in invasion appear to be invariant and essential, the earlier steps of recognition are controlled by a series of redundant, and only partially understood, receptor-ligand interactions. Reverse genetic analysis of laboratory adapted strains has identified multiple genes that when deleted can alter invasion, but how the relative contributions of each gene translate to the phenotypes of clinical isolates is far from clear. We used a forward genetic approach to identify genes responsible for variable erythrocyte invasion by phenotyping the parents and progeny of previously generated experimental genetic crosses. Linkage analysis using whole genome sequencing data revealed a single major locus was responsible for the majority of phenotypic variation in two invasion pathways. This locus contained the PfRh2a and PfRh2b genes, members of one of the major invasion ligand gene families, but not widely thought to play such a prominent role in specifying invasion phenotypes. Variation in invasion pathways was linked to significant differences in PfRh2a and PfRh2b expression between parasite lines, and their role in specifying alternative invasion was confirmed by CRISPR-Cas9-mediated genome editing. Expansion of the analysis to a large set of clinical P. falciparum isolates revealed common deletions, suggesting that variation at this locus is a major cause of invasion phenotypic variation in the endemic setting. This work has implications for blood-stage vaccine development and will help inform the design and location of future large-scale studies of invasion in clinical isolates. Plasmodium parasites cause more than 200 million cases of malaria each year. All the symptoms of malaria are caused after Plasmodium parasites invade human red blood cells. Once inside, they grow, multiply and break open the red blood cells to release new parasites. This cycle is repeated every 48 hours, rapidly amplifying the number of parasites and causing severe anemia and other complications. Plasmodium falciparum, the parasite species responsible for almost all malaria deaths, can use multiple different pathways to invade human red blood cells, but the relative importance of each is not well understood. We tested the invasion pathways used by a collection of closely related parasites and compared their genome sequences to identify the genes responsible. This analysis revealed that expression differences in two neighboring genes of the Reticulocyte Binding Homologue family are responsible for most of the variation in two invasion pathways. P. falciparum may use variation in these genes to avoid the immune system or adapt to specific blood groups, which has important implications for vaccine development against malaria.
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Affiliation(s)
- Susana Campino
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- * E-mail: (SC); (JCR)
| | - Alejandro Marin-Menendez
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Alison Kemp
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Nadia Cross
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Laura Drought
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Thomas D. Otto
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Centre of Immunobiology, Institute of Infection, Immunity & Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Matt Ravenhall
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Frank Schwach
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Gareth Girling
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Magnus Manske
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Michel Theron
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Kelda Gould
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Eleanor Drury
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Taane G. Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
- Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - Dominic P. Kwiatkowski
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Alena Pance
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Julian C. Rayner
- Malaria Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- * E-mail: (SC); (JCR)
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32
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Abstract
Eukaryotic pathogens must survive in different hosts, respond to changing environments, and exploit specialized niches to propagate. Plasmodium parasites cause human malaria during bloodstream infections, where they must persist long enough to be transmitted. Parasites have evolved diverse strategies of variant gene expression that control critical biological processes of blood-stage infections, including antigenic variation, erythrocyte invasion, innate immune evasion, and nutrient acquisition, as well as life-cycle transitions. Epigenetic mechanisms within the parasite are being elucidated, with discovery of epigenomic marks associated with gene silencing and activation, and the identification of epigenetic regulators and chromatin proteins that are required for the switching and maintenance of gene expression. Here, we review the key epigenetic processes that facilitate transition through the parasite life cycle and epigenetic regulatory mechanisms utilized by Plasmodium parasites to survive changing environments and consider epigenetic switching in the context of the outcome of human infections.
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Affiliation(s)
- Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA; ,
| | - Kristen M Skillman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA; ,
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Bunnik EM, Cook KB, Varoquaux N, Batugedara G, Prudhomme J, Cort A, Shi L, Andolina C, Ross LS, Brady D, Fidock DA, Nosten F, Tewari R, Sinnis P, Ay F, Vert JP, Noble WS, Le Roch KG. Changes in genome organization of parasite-specific gene families during the Plasmodium transmission stages. Nat Commun 2018; 9:1910. [PMID: 29765020 PMCID: PMC5954139 DOI: 10.1038/s41467-018-04295-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 04/18/2018] [Indexed: 12/20/2022] Open
Abstract
The development of malaria parasites throughout their various life cycle stages is coordinated by changes in gene expression. We previously showed that the three-dimensional organization of the Plasmodium falciparum genome is strongly associated with gene expression during its replication cycle inside red blood cells. Here, we analyze genome organization in the P. falciparum and P. vivax transmission stages. Major changes occur in the localization and interactions of genes involved in pathogenesis and immune evasion, host cell invasion, sexual differentiation, and master regulation of gene expression. Furthermore, we observe reorganization of subtelomeric heterochromatin around genes involved in host cell remodeling. Depletion of heterochromatin protein 1 (PfHP1) resulted in loss of interactions between virulence genes, confirming that PfHP1 is essential for maintenance of the repressive center. Our results suggest that the three-dimensional genome structure of human malaria parasites is strongly connected with transcriptional activity of specific gene families throughout the life cycle.
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Affiliation(s)
- Evelien M Bunnik
- Department of Microbiology, Immunology & Molecular Genetics, The University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX, 78229, USA
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Kate B Cook
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA
| | - Nelle Varoquaux
- Department of Statistics, University of California, 367 Evans Hall, Berkeley, CA, 94720, USA
- Berkeley Institute for Data Science, 190 Doe Library, Berkeley, CA, 94720, USA
- MINES ParisTech, PSL Research University, CBIO-Centre for Computational Biology, 60 boulevard Saint-Michel, 75006, Paris, France
- Institut Curie, 75248, Paris, France
- U900, INSERM, Paris, 75248, France
| | - Gayani Batugedara
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Jacques Prudhomme
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Anthony Cort
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA
| | - Lirong Shi
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615N. Wolfe Street, E5132, Baltimore, MD, 21205, USA
| | - Chiara Andolina
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research building, University of Oxford, Old Road campus, Roosevelt Drive, Headington, Oxford, OX3 7FZ, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, 63110, Thailand
| | - Leila S Ross
- Department of Microbiology and Immunology, Columbia University Medical Center, 701W. 168 St., HHSC 1208, New York, NY, 10032, USA
| | - Declan Brady
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK
| | - David A Fidock
- Department of Microbiology and Immunology, Columbia University Medical Center, 701W. 168 St., HHSC 1208, New York, NY, 10032, USA
- Division of Infectious Diseases, Department of Medicine, Columbia University, New York, NY, 10032, USA
| | - Francois Nosten
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research building, University of Oxford, Old Road campus, Roosevelt Drive, Headington, Oxford, OX3 7FZ, UK
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot, Tak, 63110, Thailand
| | - Rita Tewari
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Photini Sinnis
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, 615N. Wolfe Street, E5132, Baltimore, MD, 21205, USA
| | - Ferhat Ay
- La Jolla Institute for Allergy & Immunology, 9420 Athena Cir, La Jolla, CA, 92037, USA
| | - Jean-Philippe Vert
- MINES ParisTech, PSL Research University, CBIO-Centre for Computational Biology, 60 boulevard Saint-Michel, 75006, Paris, France
- Institut Curie, 75248, Paris, France
- U900, INSERM, Paris, 75248, France
- Département de mathématiques et applications, École normale supérieure, CNRS, PSL Research University, Paris, 75005, France
| | - William Stafford Noble
- Department of Genome Sciences, University of Washington, 3720 15th Ave NE, Seattle, WA, 98195, USA.
- Department of Computer Science and Engineering, University of Washington, Seattle, WA, 98195, USA.
| | - Karine G Le Roch
- Department of Molecular, Cell and Systems Biology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA.
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CLAG3 Self-Associates in Malaria Parasites and Quantitatively Determines Nutrient Uptake Channels at the Host Membrane. mBio 2018; 9:mBio.02293-17. [PMID: 29739907 PMCID: PMC5941077 DOI: 10.1128/mbio.02293-17] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Malaria parasites increase host erythrocyte permeability to ions and nutrients via a broad-selectivity channel known as the plasmodial surface anion channel (PSAC), linked to parasite-encoded CLAG3 and two associated proteins. These proteins lack the multiple transmembrane domains typically present in channel-forming proteins, raising doubts about their precise roles. Using the virulent human Plasmodium falciparum parasite, we report that CLAG3 undergoes self-association and that this protein’s expression determines channel phenotype quantitatively. We overcame epigenetic silencing of clag3 paralogs and engineered parasites that express two CLAG3 isoforms simultaneously. Stoichiometric expression of these isoforms yielded intermediate channel phenotypes, in agreement with observed trafficking of both proteins to the host membrane. Coimmunoprecipitation and surface labeling revealed formation of CLAG3 oligomers. In vitro selections applied to these transfectant lines yielded distinct mutants with correlated changes in channel activity. These findings support involvement of the identified oligomers in PSAC formation and parasite nutrient acquisition. Malaria parasites are globally important pathogens that evade host immunity by replicating within circulating erythrocytes. To facilitate intracellular growth, these parasites increase erythrocyte nutrient uptake through an unusual ion channel. The parasite CLAG3 protein is a key determinant of this channel, but its lack of homology to known ion channels has raised questions about possible mechanisms. Using a new method that allows simultaneous expression of two different CLAG3 proteins, we identify self-association of CLAG3. The two expressed isoforms faithfully traffic to and insert in the host membrane, while remaining associated with two unrelated parasite proteins. Both the channel phenotypes and molecular changes produced upon selections with a highly specific channel inhibitor are consistent with a multiprotein complex that forms the nutrient pore. These studies support direct involvement of the CLAG3 protein in channel formation and are relevant to antimalarial drug discovery projects targeting parasite nutrient acquisition.
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Fraschka SA, Filarsky M, Hoo R, Niederwieser I, Yam XY, Brancucci NMB, Mohring F, Mushunje AT, Huang X, Christensen PR, Nosten F, Bozdech Z, Russell B, Moon RW, Marti M, Preiser PR, Bártfai R, Voss TS. Comparative Heterochromatin Profiling Reveals Conserved and Unique Epigenome Signatures Linked to Adaptation and Development of Malaria Parasites. Cell Host Microbe 2018; 23:407-420.e8. [PMID: 29503181 PMCID: PMC5853956 DOI: 10.1016/j.chom.2018.01.008] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/22/2017] [Accepted: 01/16/2018] [Indexed: 01/23/2023]
Abstract
Heterochromatin-dependent gene silencing is central to the adaptation and survival of Plasmodium falciparum malaria parasites, allowing clonally variant gene expression during blood infection in humans. By assessing genome-wide heterochromatin protein 1 (HP1) occupancy, we present a comprehensive analysis of heterochromatin landscapes across different Plasmodium species, strains, and life cycle stages. Common targets of epigenetic silencing include fast-evolving multi-gene families encoding surface antigens and a small set of conserved HP1-associated genes with regulatory potential. Many P. falciparum heterochromatic genes are marked in a strain-specific manner, increasing the parasite's adaptive capacity. Whereas heterochromatin is strictly maintained during mitotic proliferation of asexual blood stage parasites, substantial heterochromatin reorganization occurs in differentiating gametocytes and appears crucial for the activation of key gametocyte-specific genes and adaptation of erythrocyte remodeling machinery. Collectively, these findings provide a catalog of heterochromatic genes and reveal conserved and specialized features of epigenetic control across the genus Plasmodium.
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Affiliation(s)
- Sabine A Fraschka
- Department of Molecular Biology, Faculty of Science, Radboud University, 6525 GA Nijmegen, the Netherlands
| | - Michael Filarsky
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland
| | - Regina Hoo
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Igor Niederwieser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland
| | - Xue Yan Yam
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Nicolas M B Brancucci
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, UK; Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA 02155, USA
| | - Franziska Mohring
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Annals T Mushunje
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Ximei Huang
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Peter R Christensen
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot 63110, Thailand
| | - Francois Nosten
- Shoklo Malaria Research Unit, Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Mae Sot 63110, Thailand; Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine Research Building, University of Oxford Old Road Campus, Oxford OX3 7FZ, UK
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Bruce Russell
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand
| | - Robert W Moon
- Department of Immunology and Infection, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Matthias Marti
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8QQ, UK; Department of Immunology and Infectious Diseases, Harvard TH Chan School of Public Health, Boston, MA 02155, USA
| | - Peter R Preiser
- School of Biological Sciences, Nanyang Technological University, Singapore 637551, Singapore
| | - Richárd Bártfai
- Department of Molecular Biology, Faculty of Science, Radboud University, 6525 GA Nijmegen, the Netherlands.
| | - Till S Voss
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland.
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36
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Chou ES, Abidi SZ, Teye M, Leliwa-Sytek A, Rask TS, Cobbold SA, Tonkin-Hill GQ, Subramaniam KS, Sexton AE, Creek DJ, Daily JP, Duffy MF, Day KP. A high parasite density environment induces transcriptional changes and cell death in Plasmodium falciparum blood stages. FEBS J 2018; 285:848-870. [PMID: 29281179 DOI: 10.1111/febs.14370] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 12/01/2017] [Accepted: 12/20/2017] [Indexed: 12/17/2022]
Abstract
Transient regulation of Plasmodium numbers below the density that induces fever has been observed in chronic malaria infections in humans. This species transcending control cannot be explained by immunity alone. Using an in vitro system we have observed density dependent regulation of malaria population size as a mechanism to possibly explain these in vivo observations. Specifically, Plasmodium falciparum blood stages from a high but not low-density environment exhibited unique phenotypic changes during the late trophozoite (LT) and schizont stages of the intraerythrocytic cycle. These included in order of appearance: failure of schizonts to mature and merozoites to replicate, apoptotic-like morphological changes including shrinking, loss of mitochondrial membrane potential, and blebbing with eventual release of aberrant parasites from infected erythrocytes. This unique death phenotype was triggered in a stage-specific manner by sensing of a high-density culture environment. Conditions of glucose starvation, nutrient depletion, and high lactate could not induce the phenotype. A high-density culture environment induced rapid global changes in the parasite transcriptome including differential expression of genes involved in cell remodeling, clonal antigenic variation, metabolism, and cell death pathways including an apoptosis-associated metacaspase gene. This transcriptional profile was also characterized by concomitant expression of asexual and sexual stage-specific genes. The data show strong evidence to support our hypothesis that density sensing exists in P. falciparum. They indicate that an apoptotic-like mechanism may play a role in P. falciparum density regulation, which, as in yeast, has features quite distinguishable from mammalian apoptosis. DATABASE Gene expression data are available in the GEO databases under the accession number GSE91188.
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Affiliation(s)
- Evelyn S Chou
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Sabia Z Abidi
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Marian Teye
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Aleksandra Leliwa-Sytek
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Thomas S Rask
- Department of Microbiology, Division of Medical Parasitology, New York University School of Medicine, NY, USA
| | - Simon A Cobbold
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Gerry Q Tonkin-Hill
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC., Australia
| | - Krishanthi S Subramaniam
- Department of Parasitology, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool, UK
| | - Anna E Sexton
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC., Australia
| | - Darren J Creek
- Drug Delivery Disposition and Dynamics, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC., Australia
| | - Johanna P Daily
- Department of Medicine, Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Michael F Duffy
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
| | - Karen P Day
- Bio21 Institute for Molecular Science and Biotechnology and School of BioSciences, University of Melbourne, Parkville, VIC., Australia
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37
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Mira-Martínez S, van Schuppen E, Amambua-Ngwa A, Bottieau E, Affara M, Van Esbroeck M, Vlieghe E, Guetens P, Rovira-Graells N, Gómez-Pérez GP, Alonso PL, D'Alessandro U, Rosanas-Urgell A, Cortés A. Expression of the Plasmodium falciparum Clonally Variant clag3 Genes in Human Infections. J Infect Dis 2017; 215:938-945. [PMID: 28419281 PMCID: PMC5407054 DOI: 10.1093/infdis/jix053] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2016] [Accepted: 01/20/2017] [Indexed: 11/13/2022] Open
Abstract
Background Many genes of the malaria parasite Plasmodium falciparum show clonally variant expression regulated at the epigenetic level. These genes participate in fundamental host-parasite interactions and contribute to adaptive processes. However, little is known about their expression patterns during human infections. A peculiar case of clonally variant genes are the 2 nearly identical clag3 genes, clag3.1 and clag3.2, which mediate nutrient uptake and are linked to resistance to some toxic compounds. Methods We developed a procedure to characterize the expression of clag3 genes in naturally infected patients and in experimentally infected human volunteers. Results We provide the first description of clag3 expression during human infections, which revealed mutually exclusive expression and identified the gene predominantly expressed. Adaptation to culture conditions or selection with a toxic compound resulted in isolate-dependent changes in clag3 expression. We also found that clag3 expression patterns were reset during transmission stages. Conclusions Different environment conditions select for parasites with different clag3 expression patterns, implying functional differences between the proteins encoded. The epigenetic memory is likely erased before parasites start infection of a new human host. Altogether, our findings support the idea that clonally variant genes facilitate the adaptation of parasite populations to changing conditions through bet-hedging strategies.
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Affiliation(s)
- Sofía Mira-Martínez
- Institute of Tropical Medicine, Antwerp, Belgium.,Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Evi van Schuppen
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | | | | | - Muna Affara
- Medical Research Council Unit, Fajara, The Gambia
| | | | | | | | - Núria Rovira-Graells
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Gloria P Gómez-Pérez
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Pedro L Alonso
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Umberto D'Alessandro
- Institute of Tropical Medicine, Antwerp, Belgium.,Medical Research Council Unit, Fajara, The Gambia.,London School of Hygiene and Tropical Medicine, United Kingdom
| | | | - Alfred Cortés
- Barcelona Institute for Global Health (ISGlobal), Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,ICREA, Barcelona, Spain
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38
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Abstract
Organisms with identical genome sequences can show substantial differences in their phenotypes owing to epigenetic changes that result in different use of their genes. Epigenetic regulation of gene expression plays a key role in the control of several fundamental processes in the biology of malaria parasites, including antigenic variation and sexual differentiation. Some of the histone modifications and chromatin-modifying enzymes that control the epigenetic states of malaria genes have been characterized, and their functions are beginning to be unraveled. The fundamental principles of epigenetic regulation of gene expression appear to be conserved between malaria parasites and model eukaryotes, but important peculiarities exist. Here, we review the current knowledge of malaria epigenetics and discuss how it can be exploited for the development of new molecular markers and new types of drugs that may contribute to malaria eradication efforts.
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Affiliation(s)
- Alfred Cortés
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia 08036, Spain.,ICREA, Barcelona, Catalonia 08010, Spain
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Medical College of Cornell University, New York, New York 10065
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39
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Valmaseda A, Bassat Q, Aide P, Cisteró P, Jiménez A, Casellas A, Machevo S, Aguilar R, Sigaúque B, Chauhan VS, Langer C, Beeson J, Chitnis C, Alonso PL, Gaur D, Mayor A. Host age and expression of genes involved in red blood cell invasion in Plasmodium falciparum field isolates. Sci Rep 2017; 7:4717. [PMID: 28680086 PMCID: PMC5498679 DOI: 10.1038/s41598-017-05025-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/23/2017] [Indexed: 11/24/2022] Open
Abstract
Plasmodium falciparum proteins involved in erythrocyte invasion are main targets of acquired immunity and important vaccine candidates. We hypothesized that anti-parasite immunity acquired upon exposure would limit invasion-related gene (IRG) expression and affect the clinical impact of the infection. 11 IRG transcript levels were measured in P. falciparum isolates by RT-PCR, and IgG/IgM against invasion ligands by Luminex®, in 50 Mozambican adults, 25 children with severe malaria (SM) and 25 with uncomplicated malaria (UM). IRG expression differences among groups and associations between IRG expression and clinical/immunologic parameters were assessed. IRG expression diversity was higher in parasites infecting children than adults (p = 0.022). eba140 and ptramp expression decreased with age (p = 0.003 and 0.007, respectively) whereas p41 expression increased (p = 0.022). pfrh5 reduction in expression was abrupt early in life. Parasite density decreased with increasing pfrh5 expression (p < 0.001) and, only in children, parasite density increased with p41 expression (p = 0.007), and decreased with eba175 (p = 0.013). Antibody responses and IRG expression were not associated. In conclusion, IRG expression is associated with age and parasite density, but not with specific antibody responses in the acute phase of infection. Our results confirm the importance of multi-antigen vaccines development to avoid parasite immune escape when tested in malaria-exposed individuals.
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Affiliation(s)
- Aida Valmaseda
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
| | - Quique Bassat
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Pau Cisteró
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Alfons Jiménez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBEREsp), Madrid, Spain
| | - Aina Casellas
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Sonia Machevo
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Ruth Aguilar
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Betuel Sigaúque
- Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Virander S Chauhan
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Christine Langer
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - James Beeson
- Macfarlane Burnet Institute for Medical Research and Public Health, Melbourne, Victoria, Australia
| | - Chetan Chitnis
- Malaria Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), New Delhi, India
| | - Pedro L Alonso
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique
| | - Deepak Gaur
- Laboratory of Malaria and Vaccine Research, School of Biotechnology, Jawaharlal Nehru University, New Delhi, India
| | - Alfredo Mayor
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain. .,Centro de Investigação em Saúde de Manhiça (CISM), Manhiça, Mozambique.
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40
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Batugedara G, Lu XM, Bunnik EM, Le Roch KG. The Role of Chromatin Structure in Gene Regulation of the Human Malaria Parasite. Trends Parasitol 2017; 33:364-377. [PMID: 28065669 PMCID: PMC5410391 DOI: 10.1016/j.pt.2016.12.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 11/28/2016] [Accepted: 12/07/2016] [Indexed: 12/11/2022]
Abstract
The human malaria parasite, Plasmodium falciparum, depends on a coordinated regulation of gene expression for development and propagation within the human host. Recent developments suggest that gene regulation in the parasite is largely controlled by epigenetic mechanisms. Here, we discuss recent advancements contributing to our understanding of the mechanisms controlling gene regulation in the parasite, including nucleosome landscape, histone modifications, and nuclear architecture. In addition, various processes involved in regulation of parasite-specific genes and gene families are examined. Finally, we address the use of epigenetic processes as targets for novel antimalarial therapies. Collectively, these topics highlight the unique biology of P. falciparum, and contribute to our understanding of mechanisms regulating gene expression in this deadly parasite.
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Affiliation(s)
- Gayani Batugedara
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521, USA
| | - Xueqing M Lu
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521, USA
| | - Evelien M Bunnik
- Department of Microbiology, Immunology & Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Karine G Le Roch
- Department of Cell Biology and Neuroscience, University of California Riverside, Riverside, CA 92521, USA.
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41
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Gupta AP, Bozdech Z. Epigenetic landscapes underlining global patterns of gene expression in the human malaria parasite, Plasmodium falciparum. Int J Parasitol 2017; 47:399-407. [PMID: 28414071 DOI: 10.1016/j.ijpara.2016.10.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 10/15/2016] [Accepted: 10/20/2016] [Indexed: 12/31/2022]
Abstract
The dynamic chromatin landscape displaying combinatorial complexity of the epigenome impacts gene expression that underlies many events of differentiation and cell cycle progression. In the past few years, epigenetic mechanisms have emerged as important processes involved in the tight gene regulation in malaria parasites, Plasmodium spp. Focusing predominantly on Plasmodium falciparum, the species associated with the most severe form of the disease, many advances have been made in our understanding of the interaction between transcriptional regulation and epigenetic mechanisms as the pivotal processes in regulating life cycle progression, host parasite interactions and parasite adaptation to the host environment. This review focuses on the epigenome and its effect on transcriptional regulation in P. falciparum, highlighting its unique, evolutionary diverse features.
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Affiliation(s)
- Archana P Gupta
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Zbynek Bozdech
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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42
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Sherling ES, Knuepfer E, Brzostowski JA, Miller LH, Blackman MJ, van Ooij C. The Plasmodium falciparum rhoptry protein RhopH3 plays essential roles in host cell invasion and nutrient uptake. eLife 2017; 6. [PMID: 28252384 PMCID: PMC5365315 DOI: 10.7554/elife.23239] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2016] [Accepted: 02/26/2017] [Indexed: 11/18/2022] Open
Abstract
Merozoites of the protozoan parasite responsible for the most virulent form of malaria, Plasmodium falciparum, invade erythrocytes. Invasion involves discharge of rhoptries, specialized secretory organelles. Once intracellular, parasites induce increased nutrient uptake by generating new permeability pathways (NPP) including a Plasmodium surface anion channel (PSAC). RhopH1/Clag3, one member of the three-protein RhopH complex, is important for PSAC/NPP activity. However, the roles of the other members of the RhopH complex in PSAC/NPP establishment are unknown and it is unclear whether any of the RhopH proteins play a role in invasion. Here we demonstrate that RhopH3, the smallest component of the complex, is essential for parasite survival. Conditional truncation of RhopH3 substantially reduces invasive capacity. Those mutant parasites that do invade are defective in nutrient import and die. Our results identify a dual role for RhopH3 that links erythrocyte invasion to formation of the PSAC/NPP essential for parasite survival within host erythrocytes. DOI:http://dx.doi.org/10.7554/eLife.23239.001 Malaria is a life-threatening disease that affects millions of people around the world. The parasites that cause malaria have a complex life cycle that involves infecting both mosquitoes and mammals, including humans. In humans, the parasites spend part of their life cycle inside red blood cells, which causes the symptoms of the disease. In order to survive and multiply, malaria parasites need to make the red blood cell more permeable so that it can absorb nutrients from the blood stream and get rid of the toxic waste products they generate. It remains unclear how the parasites do this, but previous research has shown that the parasites produce channel-like proteins that make red blood cells more permeable to nutrients. One of the proteins involved in this process forms part of a complex with two other proteins, called RhopH2 and RhopH3. It is not known what these other two proteins do, and whether they are necessary for creating the new nutrient channels. Sherling et al. studied the RhopH3 protein to see if it is required to make red blood cells more permeable. The experiments used a genetically modified version of the parasite, in which RhopH3 no longer interacted with the two other proteins. The findings show that RhopH3 has two important roles: first, parasites need it to invade the red blood cells, and second, parasites cannot get nutrients into the red blood cell without RhopH3. Most antimalarial drugs work by preventing parasite replication in red blood cells, but parasites are becoming increasingly resistant to these drugs. Understanding which proteins allow parasites to invade and grow within blood cells will further the development of new malaria medication. The next step will be to understand the molecular mechanisms by which RhopH3 promotes invasion and subsequently facilitates nutrient uptake, and will help researchers to explore its potential as a drug target. DOI:http://dx.doi.org/10.7554/eLife.23239.002
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Affiliation(s)
- Emma S Sherling
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom.,Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Ellen Knuepfer
- Malaria Parasitology Laboratory, The Francis Crick Institute, London, United Kingdom
| | - Joseph A Brzostowski
- Laboratory of Immunogenetics Imaging Facility, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Louis H Miller
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, United States
| | - Michael J Blackman
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom.,Department of Pathogen Molecular Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Christiaan van Ooij
- Malaria Biochemistry Laboratory, The Francis Crick Institute, London, United Kingdom
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43
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Chalapareddy S, Desai SA. Malaria parasite proteins involved in nutrient channels at the host erythrocyte membrane: advances and questions for future research. INTERNATIONAL JOURNAL OF CURRENT MULTIDISCIPLINARY STUDIES 2017; 3:619-623. [PMID: 28736757 PMCID: PMC5516901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Erythrocytes infected malaria parasites have increased permeability to nutrients and other solutes, as mediated by an unusual ion channel known as the plasmodial surface anion channel (PSAC). Although the increased permeability of infected erythrocytes was identified more than 70 years ago and subsequently characterized with tracer studies, its mechanism and role in parasite biology remained unclear until the introduction of patch-clamp methods and high-throughput screening technologies. These methods discovered and implicated PSAC as the primary mechanism, determined that this channel is essential for parasite development, led to identification of the channel's genes, and stimulated antimalarial drug discovery against this target. Despite these advances, many questions remain about this unusual parasite channel. Our review highlights some recent advances and describes important questions for future research.
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Affiliation(s)
- S Chalapareddy
- Department of Biotechnology & Bioinformatics, School of Life Sciences, University of Hyderabad, Gachibowli, Telangana, India 500046
| | - SA Desai
- Laboratory of Malaria and Vector Research, Division of Intramural Research, NIAID, National Institutes of Health, Rockville, MD, USA 20852
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44
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Ito D, Schureck MA, Desai SA. An essential dual-function complex mediates erythrocyte invasion and channel-mediated nutrient uptake in malaria parasites. eLife 2017; 6. [PMID: 28221136 PMCID: PMC5349850 DOI: 10.7554/elife.23485] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Accepted: 02/16/2017] [Indexed: 11/27/2022] Open
Abstract
Malaria parasites evade immune detection by growth and replication within erythrocytes. After erythrocyte invasion, the intracellular pathogen must increase host cell uptake of nutrients from plasma. Here, we report that the parasite-encoded RhopH complex contributes to both invasion and channel-mediated nutrient uptake. As rhoph2 and rhoph3 gene knockouts were not viable in the human P. falciparum pathogen, we used conditional knockdowns to determine that the encoded proteins are essential and to identify their stage-specific functions. We exclude presumed roles for RhopH2 and CLAG3 in erythrocyte invasion but implicate a RhopH3 contribution either through ligand-receptor interactions or subsequent parasite internalization. These proteins then traffic via an export translocon to the host membrane, where they form a nutrient channel. Knockdown of either RhopH2 or RhopH3 disrupts the entire complex, interfering with organellar targeting and subsequent trafficking. Therapies targeting this complex should attack the pathogen at two critical points in its cycle. DOI:http://dx.doi.org/10.7554/eLife.23485.001 The parasites that cause malaria in humans and other animals infect and live inside red blood cells to escape attack by their hosts’ immune systems. Malaria parasites grow and multiply in red blood cells before bursting out and invading new red blood cells. To fuel this growth, the parasite needs access to sugars and other nutrients that are found outside in the bloodstream. Malaria parasites achieve this by inserting some of their own proteins into the membrane of the red blood cell to form an unusual channel that allows the nutrients to enter the cell. A parasite protein called CLAG3 (also known as RhopH1) is involved in formation of the unusual nutrient channel. Unlike most other proteins, malaria parasites make the CLAG3 protein while they are inside one cell and release it later when they invade a new red blood cell. The CLAG3 protein also binds to two other parasite proteins, called RhopH2 and RhopH3, to form a larger protein complex. However, it was not known what roles these other proteins played, or why the complex was made in the preceding red blood cell. Ito et al. have now addressed these unknowns by editing the genes of the parasite that causes the most dangerous form of malaria in people, a parasite called Plasmodium falciparum. These experiments revealed that the parasites could still invade host cells as normal if they lost CLAG3 and RhopH2. This suggests, that contrary to what was expected, CLAG3 and RhopH2 are not needed for the invasion process. Instead, the experiments revealed that RhopH3 serves a major role in invasion, either by helping the parasite to interact with or enter the new red blood cell. After the parasite has invaded the cell, this complex of three proteins is shuttled to the red blood cell’s membrane, where it inserts to help form the nutrient channel. The findings of Ito et al. reveal that one protein complex serves two unrelated but essential roles at different locations and time points in the life cycle of a malaria parasite. Since a parasite will not survive if it cannot enter a host cell and obtain nutrients, interfering with these processes by targeting this protein complex could lead to new therapies against malaria in the future. DOI:http://dx.doi.org/10.7554/eLife.23485.002
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Affiliation(s)
- Daisuke Ito
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, United States
| | - Marc A Schureck
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, United States
| | - Sanjay A Desai
- Laboratory of Malaria and Vector Research, NIAID, National Institutes of Health, Rockville, United States
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45
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Sanz S, López-Gutiérrez B, Bandini G, Damerow S, Absalon S, Dinglasan RR, Samuelson J, Izquierdo L. The disruption of GDP-fucose de novo biosynthesis suggests the presence of a novel fucose-containing glycoconjugate in Plasmodium asexual blood stages. Sci Rep 2016; 6:37230. [PMID: 27849032 PMCID: PMC5110956 DOI: 10.1038/srep37230] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/03/2016] [Indexed: 02/03/2023] Open
Abstract
Glycosylation is an important posttranslational protein modification in all eukaryotes. Besides glycosylphosphatidylinositol (GPI) anchors and N-glycosylation, O-fucosylation has been recently reported in key sporozoite proteins of the malaria parasite. Previous analyses showed the presence of GDP-fucose (GDP-Fuc), the precursor for all fucosylation reactions, in the blood stages of Plasmodium falciparum. The GDP-Fuc de novo pathway, which requires the action of GDP-mannose 4,6-dehydratase (GMD) and GDP-L-fucose synthase (FS), is conserved in the parasite genome, but the importance of fucose metabolism for the parasite is unknown. To functionally characterize the pathway we generated a PfGMD mutant and analyzed its phenotype. Although the labelling by the fucose-binding Ulex europaeus agglutinin I (UEA-I) was completely abrogated, GDP-Fuc was still detected in the mutant. This unexpected result suggests the presence of an alternative mechanism for maintaining GDP-Fuc in the parasite. Furthermore, PfGMD null mutant exhibited normal growth and invasion rates, revealing that the GDP-Fuc de novo metabolic pathway is not essential for the development in culture of the malaria parasite during the asexual blood stages. Nonetheless, the function of this metabolic route and the GDP-Fuc pool that is generated during this stage may be important for gametocytogenesis and sporogonic development in the mosquito.
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Affiliation(s)
- Sílvia Sanz
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Borja López-Gutiérrez
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Giulia Bandini
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, 72 East Concord St, Boston, MA 02118, USA
| | - Sebastian Damerow
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
| | - Sabrina Absalon
- Division of Infectious Diseases, Boston Children's Hospital and Harvard Medical School, Boston MA 02115, USA
| | - Rhoel R Dinglasan
- The University of Florida Emerging Pathogens Institute, Department of Infectious Diseases &Pathology, Gainesville FL 32611, USA
| | - John Samuelson
- Department of Molecular and Cell Biology, Boston University Goldman School of Dental Medicine, 72 East Concord St, Boston, MA 02118, USA
| | - Luis Izquierdo
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
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Rovira-Graells N, Aguilera-Simón S, Tintó-Font E, Cortés A. New Assays to Characterise Growth-Related Phenotypes of Plasmodium falciparum Reveal Variation in Density-Dependent Growth Inhibition between Parasite Lines. PLoS One 2016; 11:e0165358. [PMID: 27780272 PMCID: PMC5079629 DOI: 10.1371/journal.pone.0165358] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/11/2016] [Indexed: 11/18/2022] Open
Abstract
The growth phenotype of asexual blood stage malaria parasites can influence their virulence and also their ability to survive and achieve transmission to the next host, but there are few methods available to characterise parasite growth parameters in detail. We developed a new assay to measure growth rates at different starting parasitaemias in a 96-well format and applied it to characterise the growth of Plasmodium falciparum lines 3D7-A and 3D7-B, previously shown to have different invasion rates and to use different invasion pathways. Using this simple and accurate assay we found that 3D7-B is more sensitive to high initial parasitaemia than 3D7-A. This result indicates that different parasite lines show variation in their levels of density-dependent growth inhibition. We also developed a new assay to compare the duration of the asexual blood cycle between different parasite lines. The assay is based on the tight synchronisation of cultures to a 1 h parasite age window and the subsequent monitoring of schizont bursting and formation of new rings by flow cytometry. Using this assay we observed differences in the duration of the asexual blood cycle between parasite lines 3D7 and HB3. These two new assays will be useful to characterise variation in growth-related parameters and to identify growth phenotypes associated with the targeted deletion of specific genes or with particular genomic, transcriptomic or proteomic patterns. Furthermore, the identification of density-dependent growth inhibition as an intrinsic parasite property that varies between parasite lines expands the repertoire of measurable growth-related phenotypic traits that have the potential to influence the outcome of a malarial blood infection.
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Affiliation(s)
- Núria Rovira-Graells
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Sara Aguilera-Simón
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Elisabet Tintó-Font
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain
| | - Alfred Cortés
- ISGlobal, Barcelona Ctr. Int. Health Res. (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Catalonia, Spain
- ICREA, Barcelona, Catalonia, Spain
- * E-mail:
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Zainabadi K. Malaria Parasite CLAG3, a Protein Linked to Nutrient Channels, Participates in High Molecular Weight Membrane-Associated Complexes in the Infected Erythrocyte. PLoS One 2016; 11:e0157390. [PMID: 27299521 PMCID: PMC4907441 DOI: 10.1371/journal.pone.0157390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 05/27/2016] [Indexed: 11/24/2022] Open
Abstract
Malaria infected erythrocytes show increased permeability to a number of solutes important for parasite growth as mediated by the Plasmodial Surface Anion Channel (PSAC). The P. falciparum clag3 genes have recently been identified as key determinants of PSAC, though exactly how they contribute to channel function and whether additional host/parasite proteins are required remain unknown. To begin to answer these questions, I have taken a biochemical approach. Here I have used an epitope-tagged CLAG3 parasite to perform co-immunoprecipitation experiments using membrane fractions of infected erythrocytes. Native PAGE and mass spectrometry studies reveal that CLAG3 participate in at least three different high molecular weight complexes: a ~720kDa complex consisting of CLAG3, RHOPH2 and RHOPH3; a ~620kDa complex consisting of CLAG3 and RHOPH2; and a ~480kDa complex composed solely of CLAG3. Importantly, these complexes can be found throughout the parasite lifecycle but are absent in untransfected controls. Extracellular biotin labeling and protease susceptibility studies localize the 480kDa complex to the erythrocyte membrane. This complex, likely composed of a homo-oligomer of 160kDa CLAG3, may represent a functional subunit, possibly the pore, of PSAC.
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Affiliation(s)
- Kayvan Zainabadi
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, NIH, Rockville, Maryland, United States of America
- * E-mail:
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Weiss GE, Crabb BS, Gilson PR. Overlaying Molecular and Temporal Aspects of Malaria Parasite Invasion. Trends Parasitol 2016; 32:284-295. [DOI: 10.1016/j.pt.2015.12.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/02/2015] [Accepted: 12/10/2015] [Indexed: 12/31/2022]
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Plasmodium falciparum PfSET7: enzymatic characterization and cellular localization of a novel protein methyltransferase in sporozoite, liver and erythrocytic stage parasites. Sci Rep 2016; 6:21802. [PMID: 26902486 PMCID: PMC4763181 DOI: 10.1038/srep21802] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 02/01/2016] [Indexed: 02/07/2023] Open
Abstract
Epigenetic control via reversible histone methylation regulates transcriptional activation throughout the malaria parasite genome, controls the repression of multi-copy virulence gene families and determines sexual stage commitment. Plasmodium falciparum encodes ten predicted SET domain-containing protein methyltransferases, six of which have been shown to be refractory to knock-out in blood stage parasites. We have expressed and purified the first recombinant malaria methyltransferase in sufficient quantities to perform a full enzymatic characterization and reveal the ill-defined PfSET7 is an AdoMet-dependent histone H3 lysine methyltransferase with highest activity towards lysines 4 and 9. Steady-state kinetics of the PfSET7 enzyme are similar to previously characterized histone methyltransferase enzymes from other organisms, however, PfSET7 displays specific protein substrate preference towards nucleosomes with pre-existing histone H3 lysine 14 acetylation. Interestingly, PfSET7 localizes to distinct cytoplasmic foci adjacent to the nucleus in erythrocytic and liver stage parasites, and throughout the cytoplasm in salivary gland sporozoites. Characterized recombinant PfSET7 now allows for target based inhibitor discovery. Specific PfSET7 inhibitors can aid in further investigating the biological role of this specific methyltransferase in transmission, hepatic and blood stage parasites, and may ultimately lead to the development of suitable antimalarial drug candidates against this novel class of essential parasite enzymes.
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Affiliation(s)
- Andrew P Waters
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary & Life Sciences and Wellcome Trust Centre for Molecular Parasitology, University of Glasgow, Scotland, United Kingdom
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