1
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Abdi AI, Achcar F, Sollelis L, Silva-Filho JL, Mwikali K, Muthui M, Mwangi S, Kimingi HW, Orindi B, Andisi Kivisi C, Alkema M, Chandrasekar A, Bull PC, Bejon P, Modrzynska K, Bousema T, Marti M. Plasmodium falciparum adapts its investment into replication versus transmission according to the host environment. eLife 2023; 12:e85140. [PMID: 36916164 PMCID: PMC10059685 DOI: 10.7554/elife.85140] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 03/01/2023] [Indexed: 03/14/2023] Open
Abstract
The malaria parasite life cycle includes asexual replication in human blood, with a proportion of parasites differentiating to gametocytes required for transmission to mosquitoes. Commitment to differentiate into gametocytes, which is marked by activation of the parasite transcription factor ap2-g, is known to be influenced by host factors but a comprehensive model remains uncertain. Here, we analyze data from 828 children in Kilifi, Kenya with severe, uncomplicated, and asymptomatic malaria infection over 18 years of falling malaria transmission. We examine markers of host immunity and metabolism, and markers of parasite growth and transmission investment. We find that inflammatory responses associated with reduced plasma lysophosphatidylcholine levels are associated with markers of increased investment in parasite sexual reproduction (i.e. transmission investment) and reduced growth (i.e. asexual replication). This association becomes stronger with falling transmission and suggests that parasites can rapidly respond to the within-host environment, which in turn is subject to changing transmission.
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Affiliation(s)
- Abdirahman I Abdi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Fiona Achcar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - Lauriane Sollelis
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | - João Luiz Silva-Filho
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
| | | | | | | | | | | | - Cheryl Andisi Kivisi
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
- Pwani University Biosciences Research Centre, Pwani UniversityKilifiKenya
| | - Manon Alkema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Amrita Chandrasekar
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Peter C Bull
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research ProgrammeKilifiKenya
| | - Katarzyna Modrzynska
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
| | - Teun Bousema
- Radboud University Nijmegen Medical CentreNijmegenNetherlands
| | - Matthias Marti
- Wellcome Center for Integrative Parasitology, University of GlasgowGlasgowUnited Kingdom
- Institute of Parasitology, Vetsuisse and Medical Faculty, University of ZurichZurichSwitzerland
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2
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Merrick CJ. Histone lactylation: a new epigenetic axis for host-parasite signalling in malaria? Trends Parasitol 2023; 39:12-16. [PMID: 36357308 DOI: 10.1016/j.pt.2022.10.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/21/2022] [Accepted: 10/21/2022] [Indexed: 11/09/2022]
Abstract
Epigenetic modifications play important roles in the biology of malaria parasites. The new epigenetic mark histone lactylation, discovered only recently in humans, is also present in malaria parasites. It may have important functions as a key player in the epigenetic repertoire of Plasmodium.
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Affiliation(s)
- Catherine J Merrick
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK.
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3
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Edwards-Smallbone J, Jensen AL, Roberts LE, Totañes FIG, Hart SR, Merrick CJ. Plasmodium falciparum GBP2 Is a Telomere-Associated Protein That Binds to G-Quadruplex DNA and RNA. Front Cell Infect Microbiol 2022; 12:782537. [PMID: 35273922 PMCID: PMC8902816 DOI: 10.3389/fcimb.2022.782537] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 01/24/2022] [Indexed: 02/02/2023] Open
Abstract
In the early-diverging protozoan parasite Plasmodium, few telomere-binding proteins have been identified and several are unique. Plasmodium telomeres, like those of most eukaryotes, contain guanine-rich repeats that can form G-quadruplex structures. In model systems, quadruplex-binding drugs can disrupt telomere maintenance and some quadruplex-binding drugs are potent anti-plasmodial agents. Therefore, telomere-interacting and quadruplex-interacting proteins may offer new targets for anti-malarial therapy. Here, we report that P. falciparum GBP2 is such a protein. It was identified via 'Proteomics of Isolated Chromatin fragments', applied here for the first time in Plasmodium. In vitro, PfGBP2 binds specifically to G-rich telomere repeats in quadruplex form and it can also bind to G-rich RNA. In vivo, PfGBP2 partially colocalises with the known telomeric protein HP1 but is also found in the cytoplasm, probably due to its affinity for RNA. Consistently, its interactome includes numerous RNA-associated proteins. PfGBP2 is evidently a multifunctional DNA/RNA-binding factor in Plasmodium.
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Affiliation(s)
- James Edwards-Smallbone
- Centre for Applied Entomology and Parasitology, Faculty of Natural Sciences, Keele University, Staffordshire, United Kingdom
| | - Anders L. Jensen
- Department of Pathology, Cambridge University, Cambridge, United Kingdom
| | - Lydia E. Roberts
- Department of Pathology, Cambridge University, Cambridge, United Kingdom
| | | | - Sarah R. Hart
- School of Medicine, Faculty of Medicine and Health Sciences, Keele University, Staffordshire, United Kingdom
| | - Catherine J. Merrick
- Department of Pathology, Cambridge University, Cambridge, United Kingdom,*Correspondence: Catherine J. Merrick,
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4
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Alteration of the expression of sirtuins and var genes by heat shock in the malaria parasite Plasmodium falciparum. Mol Biochem Parasitol 2022; 248:111458. [PMID: 35031386 DOI: 10.1016/j.molbiopara.2022.111458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/27/2021] [Accepted: 01/10/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND In Plasmodium falciparum the monoallelic expression of var virulence genes is regulated through epigenetic mechanisms. A study in the Gambia showed that an increase in var gene expression is associated with fever, high blood lactate with commonly-expressed var genes expressed in patients with severe malaria. A strong association was demonstrated between the upregulation of PfSir2A and group B var genes. A subsequent study in Kenya extended this association to show a link between elevated expression of PfSir2A and overall var transcript levels. We investigate here the link between heat shock and/or lactate levels on sirtuin and var gene expression levels in vitro. METHODS In vitro experiments were conducted using laboratory and recently-laboratory-adapted Kenyan isolates of P. falciparum. To investigate a potential cause-and-effect relationship between host stress factors and parasite gene expression, qPCR was used to measure the expression of sirtuins and var genes after highly synchronous cultured parasites had been exposed to 2 h or 6 h of heat shock at 40 °C or elevated lactate. RESULTS Heat shock was shown to increase the expression ofPfSir2B in the trophozoites, whereas exposure to lactate was not. After the ring stages were exposed to heat shock and lactate, there was no alteration in the expression of sirtuins and severe-disease-associated upsA and upsB var genes. The association between high blood lactate and sirtuin/var gene expression that was previously observed in vivo appears to be coincidental rather than causative. CONCLUSIONS This study demonstrates that heat stress in a laboratory and recently-laboratory-adapted isolates of P. falciparum results in a small increase in PfSir2B transcripts in the trophozoite stages only. This finding adds to our understanding of how patient factors can influence the outcome of Plasmodium falciparum infections.
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5
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Sahu PK, Duffy FJ, Dankwa S, Vishnyakova M, Majhi M, Pirpamer L, Vigdorovich V, Bage J, Maharana S, Mandala W, Rogerson SJ, Seydel KB, Taylor TE, Kim K, Sather DN, Mohanty A, Mohanty RR, Mohanty A, Pattnaik R, Aitchison JD, Hoffman A, Mohanty S, Smith JD, Bernabeu M, Wassmer SC. Determinants of brain swelling in pediatric and adult cerebral malaria. JCI Insight 2021; 6:145823. [PMID: 34549725 PMCID: PMC8492338 DOI: 10.1172/jci.insight.145823] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 07/28/2021] [Indexed: 01/08/2023] Open
Abstract
Cerebral malaria (CM) affects children and adults, but brain swelling is more severe in children. To investigate features associated with brain swelling in malaria, we performed blood profiling and brain MRI in a cohort of pediatric and adult patients with CM in Rourkela, India, and compared them with an African pediatric CM cohort in Malawi. We determined that higher plasma Plasmodium falciparum histidine rich protein 2 (PfHRP2) levels and elevated var transcripts that encode for binding to endothelial protein C receptor (EPCR) were linked to CM at both sites. Machine learning models trained on the African pediatric cohort could classify brain swelling in Indian children CM cases but had weaker performance for adult classification, due to overall lower parasite var transcript levels in this age group and more severe thrombocytopenia in Rourkela adults. Subgrouping of patients with CM revealed higher parasite biomass linked to severe thrombocytopenia and higher Group A–EPCR var transcripts in mild thrombocytopenia. Overall, these findings provide evidence that higher parasite biomass and a subset of Group A–EPCR binding variants are common features in children and adult CM cases, despite age differences in brain swelling.
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Affiliation(s)
- Praveen K Sahu
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Fergal J Duffy
- Seattle Children's Research Institute, Seattle, Washington, USA
| | - Selasi Dankwa
- Seattle Children's Research Institute, Seattle, Washington, USA
| | | | | | - Lukas Pirpamer
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | | | - Jabamani Bage
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Sameer Maharana
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Wilson Mandala
- Malawi University of Science and Technology, Limbe, Malawi
| | - Stephen J Rogerson
- Department of Medicine, The Doherty Institute, University of Melbourne, Melbourne, Australia
| | - Karl B Seydel
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA.,Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Terrie E Taylor
- Department of Osteopathic Medical Specialties, College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, USA.,Blantyre Malaria Project, Kamuzu University of Health Sciences, Blantyre, Malawi
| | - Kami Kim
- Division of Infectious Diseases and International Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, USA
| | - D Noah Sather
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Akshaya Mohanty
- Infectious Diseases Biology Unit, Institute of Life Sciences, Bhubaneswar, Odisha, India
| | | | - Anita Mohanty
- Department of Intensive Care, IGH, Rourkela, Odisha, India
| | | | - John D Aitchison
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Angelika Hoffman
- Department of Neuroradiology, University Hospital Heidelberg, Heidelberg, Germany.,University Institute of Diagnostic and Interventional Neuroradiology, University Hospital Bern, Inselspital, University of Bern, Switzerland
| | - Sanjib Mohanty
- Center for the Study of Complex Malaria in India, Ispat General Hospital (IGH), Rourkela, Odisha, India
| | - Joseph D Smith
- Seattle Children's Research Institute, Seattle, Washington, USA.,Department of Pediatrics, University of Washington, Seattle, Washington, USA
| | - Maria Bernabeu
- Seattle Children's Research Institute, Seattle, Washington, USA.,European Molecular Biology Laboratory (EMBL), Barcelona, Spain
| | - Samuel C Wassmer
- Department of Infection Biology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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6
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How much epigenetics and quantitative trait loci (QTL) mapping tell us about parasitism maintenance and resistance/susceptibility to hosts. Biochim Biophys Acta Mol Basis Dis 2021; 1867:166214. [PMID: 34271118 DOI: 10.1016/j.bbadis.2021.166214] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/07/2021] [Indexed: 01/20/2023]
Abstract
Interactions between the environment, parasites, vectors, and/or intermediate hosts are complex and involve several factors that define the success or failure of an infection. Among these interactions that can affect infections by a parasite, it is possible to highlight the genetic and epigenetic mechanisms in hosts and parasites. The interaction between genetics, epigenetics, infection, and the host's internal and external environment is decisive and dictates the outcome of a parasitic infection and the resistance, susceptibility, and transmission of this parasite. Epigenetic changes become important mediators in the regulation of gene expression, allowing the evasion of the parasite to immune host barriers, its transmission to new hosts, and the end of its development cycle. Epigenetics is a new frontier in the understanding of the interaction mechanisms between parasite and host that, along with information from the gene regions associated with complex phenotypic variations, the Quantitative Trait Loci, brings new possibilities to investigate more modern and efficient approaches to the treatment, control, and eradication of parasitic diseases. In this brief review, a general overview of the use of epigenetic information and mapping of Quantitative Trait Loci was summarized, both in genes of parasites and hosts, for understanding the mechanisms of resistance and/or susceptibility in parasitic relationships; also, the main search platforms were quantitatively compared, aiming to facilitate access data produced over a period of twenty years.
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7
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Antibody Levels to Plasmodium falciparum Erythrocyte Membrane Protein 1-DBLγ11 and DBLδ-1 Predict Reduction in Parasite Density. mSystems 2021; 6:e0034721. [PMID: 34128693 PMCID: PMC8269226 DOI: 10.1128/msystems.00347-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a variant surface antigen family expressed on infected red blood cells that plays a role in immune evasion and mediates adhesion to vascular endothelium. PfEMP1s are potential targets of protective antibodies as suggested by previous seroepidemiology studies. Here, we used previously reported proteomic analyses of PfEMP1s of clinical parasite isolates collected from Malian children to identify targets of immunity. We designed a peptide library representing 11 PfEMP1 domains commonly identified on clinical isolates by membrane proteomics and then examined peptide-specific antibody responses in Malian children. The number of previous malaria infections was associated with development of PfEMP1 antibodies to peptides from domains CIDRα1.4, DBLγ11, DBLβ3, and DBLδ1. A zero-inflated negative binomial model with random effects (ZINBRE) was used to identify peptide reactivities that were associated with malaria risk. This peptide selection and serosurvey strategy revealed that high antibody levels to peptides from DBLγ11 and DBLδ1 domains correlated with decreased parasite burden in future infections, supporting the notion that specific PfEMP1 domains play a role in protective immunity. IMPORTANCEPlasmodium infection causes devastating disease and high mortality in young children. Immunity develops progressively as children acquire protection against severe disease, although reinfections and recrudescences still occur throughout life in areas of endemicity, partly due to parasite immunoevasion via switching of variant proteins such as Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) expressed on the infected erythrocyte surface. Understanding the mechanisms behind antibody protection can advance development of new therapeutic interventions that address this challenge. PfEMP1 domain-specific antibodies have been linked to reduction in severe malaria; however, the large diversity of PfEMP1 domains in circulating parasites has not been fully investigated. We designed representative peptides based on B cell epitopes of PfEMP1 domains identified in membranes of clinical parasite isolates and surveyed peptide-specific antibody responses among young Malian children in a longitudinal birth cohort. We examined previous infections and age as factors contributing to antibody acquisition and identified antibody specificities that predict malaria risk.
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8
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Rashidi S, Tuteja R, Mansouri R, Ali-Hassanzadeh M, Shafiei R, Ghani E, Karimazar M, Nguewa P, Manzano-Román R. The main post-translational modifications and related regulatory pathways in the malaria parasite Plasmodium falciparum: An update. J Proteomics 2021; 245:104279. [PMID: 34089893 DOI: 10.1016/j.jprot.2021.104279] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 05/18/2021] [Accepted: 05/27/2021] [Indexed: 12/14/2022]
Abstract
There are important challenges when investigating individual post-translational modifications (PTMs) or protein interaction network and delineating if PTMs or their changes and cross-talks are involved during infection, disease initiation or as a result of disease progression. Proteomics and in silico approaches now offer the possibility to complement each other to further understand the regulatory involvement of these modifications in parasites and infection biology. Accordingly, the current review highlights key expressed or altered proteins and PTMs are invisible switches that turn on and off the function of most of the proteins. PTMs include phosphorylation, glycosylation, ubiquitylation, palmitoylation, myristoylation, prenylation, acetylation, methylation, and epigenetic PTMs in P. falciparum which have been recently identified. But also other low-abundant or overlooked PTMs that might be important for the parasite's survival, infectivity, antigenicity, immunomodulation and pathogenesis. We here emphasize the PTMs as regulatory pathways playing major roles in the biology, pathogenicity, metabolic pathways, survival, host-parasite interactions and the life cycle of P. falciparum. Further validations and functional characterizations of such proteins might confirm the discovery of therapeutic targets and might most likely provide valuable data for the treatment of P. falciparum, the main cause of severe malaria in human.
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Affiliation(s)
- Sajad Rashidi
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Renu Tuteja
- Parasite Biology Group, ICGEB, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Reza Mansouri
- Department of Immunology, Faculty of Medicine, Shahid Sadoughi University of Medical Sciences and Health Services, Yazd, Iran
| | - Mohammad Ali-Hassanzadeh
- Department of Immunology, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran
| | - Reza Shafiei
- Vector-borne Diseases Research Center, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Esmaeel Ghani
- Endocrinology and Metabolism Research Center, Hormozgan University of Medical Sciences, Bandar Abbas, Iran
| | - Mohammadreza Karimazar
- Department of Parasitology and Mycology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Paul Nguewa
- University of Navarra, ISTUN Instituto de Salud Tropical, Department of Microbiology and Parasitology, IdiSNA (Navarra Institute for Health Research), c/Irunlarrea 1, 31008 Pamplona, Spain.
| | - Raúl Manzano-Román
- Proteomics Unit, Cancer Research Centre (IBMCC/CSIC/USAL/IBSAL), 37007, Salamanca, Spain.
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9
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Tabassum W, Bhattacharyya S, Varunan SM, Bhattacharyya MK. Febrile temperature causes transcriptional downregulation of Plasmodium falciparum Sirtuins through Hsp90-dependent epigenetic modification. Mol Microbiol 2021; 115:1025-1038. [PMID: 33538363 DOI: 10.1111/mmi.14692] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 01/30/2021] [Accepted: 01/30/2021] [Indexed: 11/28/2022]
Abstract
Sirtuins (PfSIR2A and PfSIR2B) are implicated to play pivotal roles in the silencing of sub-telomeric genes and the maintenance of telomere length in P. falciparum 3D7 strain. Here, we identify the key factors that regulate the cellular abundance and activity of these two histone deacetylases. Our results demonstrate that PfSIR2A and PfSIR2B are transcriptionally downregulated at the mid-ring stage in response to febrile temperature. We found that the molecular chaperone PfHsp90 acts as a repressor of PfSIR2A & B transcription. By virtue of its presence in the PfSIR2A & B promoter proximal regions PfHsp90 helps recruiting H3K9me3, conferring heterochromatic state, and thereby leading to the downregulation of PfSIR2A & B transcription. Such transcriptional downregulation can be reversed by the addition of 17-(allylamino)-17-demethoxygeldanamycin or Radicicol, two potent inhibitors of PfHsp90. The reduced occupancy of PfSir2 at sub-telomeric var promoters leads to the de-repression of var genes. Thus, here we uncover how exposure to febrile temperature, a hallmark of malaria, enables the parasites to manipulate the expression of the two prominent epigenetic modifiers PfSir2A and PfSir2B.
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Affiliation(s)
- Wahida Tabassum
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Sunanda Bhattacharyya
- Department of Biotechnology and Bioinformatics, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Shalu M Varunan
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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10
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Kumar M, Skillman K, Duraisingh MT. Linking nutrient sensing and gene expression in Plasmodium falciparum blood-stage parasites. Mol Microbiol 2020; 115:891-900. [PMID: 33236377 DOI: 10.1111/mmi.14652] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/17/2020] [Accepted: 11/20/2020] [Indexed: 12/21/2022]
Abstract
Malaria is one of the most life-threatening infectious diseases worldwide, caused by infection of humans with parasites of the genus Plasmodium. The complex life cycle of Plasmodium parasites is shared between two hosts, with infection of multiple cell types, and the parasite needs to adapt for survival and transmission through significantly different metabolic environments. Within the blood-stage alone, parasites encounter changing levels of key nutrients, including sugars, amino acids, and lipids, due to differences in host dietary nutrition, cellular tropism, and pathogenesis. In this review, we consider the mechanisms that the most lethal of malaria parasites, Plasmodium falciparum, uses to sense nutrient levels and elicit changes in gene expression during blood-stage infections. These changes are brought about by several metabolic intermediates and their corresponding sensor proteins. Sensing of distinct nutritional signals can drive P. falciparum to alter the key blood-stage processes of proliferation, antigenic variation, and transmission.
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Affiliation(s)
- Manish Kumar
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Kristen Skillman
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, Boston, MA, USA
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11
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Matthews KA, Senagbe KM, Nötzel C, Gonzales CA, Tong X, Rijo-Ferreira F, Bhanu NV, Miguel-Blanco C, Lafuente-Monasterio MJ, Garcia BA, Kafsack BFC, Martinez ED. Disruption of the Plasmodium falciparum Life Cycle through Transcriptional Reprogramming by Inhibitors of Jumonji Demethylases. ACS Infect Dis 2020; 6:1058-1075. [PMID: 32272012 PMCID: PMC7748244 DOI: 10.1021/acsinfecdis.9b00455] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
![]()
Little
is known about the role of the three Jumonji C (JmjC) enzymes
in Plasmodium falciparum (Pf). Here,
we show that JIB-04 and other established inhibitors of mammalian
JmjC histone demethylases kill asexual blood stage parasites and are
even more potent at blocking gametocyte development and gamete formation.
In late stage parasites, JIB-04 increased levels of trimethylated
lysine residues on histones, suggesting the inhibition of P. falciparum Jumonji demethylase activity. These epigenetic
defects coincide with deregulation of invasion, cell motor, and sexual
development gene programs, including gene targets coregulated by the
PfAP2-I transcription factor and chromatin-binding factor, PfBDP1.
Mechanistically, we demonstrate that PfJmj3 converts 2-oxoglutarate
to succinate in an iron-dependent manner consistent with mammalian
Jumonji enzymes, and this catalytic activity is inhibited by JIB-04
and other Jumonji inhibitors. Our pharmacological studies of Jumonji
activity in the malaria parasite provide evidence that inhibition
of these enzymatic activities is detrimental to the parasite.
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Affiliation(s)
- Krista A. Matthews
- Department of Pharmacology, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
| | - Kossi M. Senagbe
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
| | - Christopher Nötzel
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Avenue, W-705, New York, New York 10065, United States
- Biochemistry, Cell & Molecular Biology Graduate Program, Weill Cornell Medicine, 1300 York Avenue, W-705, New York, New York 10065, United States
| | - Christopher A. Gonzales
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
| | - Xinran Tong
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Avenue, W-705, New York, New York 10065, United States
| | - Filipa Rijo-Ferreira
- Department of Neuroscience, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
| | - Natarajan V. Bhanu
- Epigenetics Program, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd., Bldg. 421, Philadelphia, Pennsylvania 19104, United States
| | - Celia Miguel-Blanco
- Tres Cantos Medicines Development Campus, GlaxoSmithKline, P.T.M. Severo Ochoa, Tres Cantos, Madrid 28760, Spain
| | | | - Benjamin A. Garcia
- Epigenetics Program, Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 3400 Civic Center Blvd., Bldg. 421, Philadelphia, Pennsylvania 19104, United States
| | - Björn F. C. Kafsack
- Department of Microbiology & Immunology, Weill Cornell Medicine, 1300 York Avenue, W-705, New York, New York 10065, United States
- Biochemistry, Cell & Molecular Biology Graduate Program, Weill Cornell Medicine, 1300 York Avenue, W-705, New York, New York 10065, United States
| | - Elisabeth D. Martinez
- Department of Pharmacology, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
- Hamon Center for Therapeutic Oncology Research, The University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, Texas 75390, United States
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12
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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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13
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Rodríguez Y, Gerona-Navarro G, Osman R, Zhou MM. In silico design and molecular basis for the selectivity of Olinone toward the first over the second bromodomain of BRD4. Proteins 2020; 88:414-430. [PMID: 31587361 PMCID: PMC6982606 DOI: 10.1002/prot.25818] [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: 05/27/2019] [Revised: 09/12/2019] [Accepted: 09/17/2019] [Indexed: 01/11/2023]
Abstract
Bromodomains (BrDs), a conserved structural module in chromatin-associated proteins, are well known for recognizing ε-N-acetyl lysine residues on histones. One of the most relevant BrDs is BRD4, a tandem BrD containing protein (BrD1 and BrD2) that plays a critical role in numerous diseases including cancer. Growing evidence shows that the two BrDs of BRD4 have different biological functions; hence selective ligands that can be used to study their functions are of great interest. Here, as a follow-up of our previous work, we first provide a detailed characterization study of the in silico rational design of Olinone as part of a series of five tetrahydropyrido indole-based compounds as BRD4 BrD1 inhibitors. Additionally, we investigated the molecular basis for Olinone's selective recognition by BrD1 over BrD2. Molecular dynamics simulations, free energy calculations, and conformational analyses of the apo-BRD4-BrD1|2 and BRD4-BrD1|2/Olinone complexes showed that Olinone's selectivity is facilitated by five key residues: Leu92 in BrD1|385 in BrD2 of ZA loop, Asn140|433, Asp144|His437 and Asp145|Glu438 of BC loop, and Ile146|Val49 of helix C. Furthermore, the difference in hydrogen bonds number and in mobility of the ZA and BC loops of the acetyl-lysine binding site between BRD4 BrD1/Olinone and BrD2/Olinone complexes also contribute to the difference in Olinone's binding affinity and selectivity toward BrD1 over BrD2. Altogether, our computer-aided molecular design techniques can effectively guide the development of small-molecule BRD4 BrD1 inhibitors, explain their selectivity origin, and further open doors to the design of new therapeutically improved derivatives.
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Affiliation(s)
- Yoel Rodríguez
- Department of Natural Sciences, Hostos Community
College of CUNY, Bronx, NY 10451, USA,Department of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA,Corresponding Authors: Yoel Rodríguez.
Address: Department of Natural Sciences, Room A-507F, Hostos Community College
of CUNY, Bronx, NY 10451, USA. Phone: +1 (718) 518-4134, Fax: +1 (718) 518-1120.
- ; Ming-Ming Zhou. Address: Department
of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, 1425
Madison Avenue, Box 1677, New York, NY 10029, USA. Phone: +1 (212) 659-8652.
Fax: +1 (212) 849-2456.
| | - Guillermo Gerona-Navarro
- Department of Chemistry, Brooklyn College, 2900
Bedford Avenue, Room 351 NE, Brooklyn, NY 11210, USA,Ph.D. Program in Chemistry. The Graduate Center of
The City University of New York, NY 10016, USA
| | - Roman Osman
- Department of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA
| | - Ming-Ming Zhou
- Department of Pharmacological Sciences, Icahn School
of Medicine at Mount Sinai, 1425 Madison Avenue, New York, NY 10029, USA,Corresponding Authors: Yoel Rodríguez.
Address: Department of Natural Sciences, Room A-507F, Hostos Community College
of CUNY, Bronx, NY 10451, USA. Phone: +1 (718) 518-4134, Fax: +1 (718) 518-1120.
- ; Ming-Ming Zhou. Address: Department
of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, 1425
Madison Avenue, Box 1677, New York, NY 10029, USA. Phone: +1 (212) 659-8652.
Fax: +1 (212) 849-2456.
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14
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Bhowmick K, Tehlan A, Sunita, Sudhakar R, Kaur I, Sijwali PS, Krishnamachari A, Dhar SK. Plasmodium falciparum GCN5 acetyltransferase follows a novel proteolytic processing pathway that is essential for its function. J Cell Sci 2020; 133:jcs.236489. [PMID: 31862795 DOI: 10.1242/jcs.236489] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 11/29/2019] [Indexed: 12/18/2022] Open
Abstract
The pathogenesis of human malarial parasite Plasmodium falciparum is interlinked with its timely control of gene expression during its complex life cycle. In this organism, gene expression is partially controlled through epigenetic mechanisms, the regulation of which is, hence, of paramount importance to the parasite. The P. falciparum (Pf)-GCN5 histone acetyltransferase (HAT), an essential enzyme, acetylates histone 3 and regulates global gene expression in the parasite. Here, we show the existence of a novel proteolytic processing for PfGCN5 that is crucial for its activity in vivo We find that a cysteine protease-like enzyme is required for the processing of PfGCN5 protein. Immunofluorescence and immuno-electron microscopy analysis suggest that the processing event occurs in the vicinity of the digestive vacuole of the parasite following its trafficking through the classical ER-Golgi secretory pathway, before it subsequently reaches the nucleus. Furthermore, blocking of PfGCN5 processing leads to the concomitant reduction of its occupancy at the gene promoters and a reduced H3K9 acetylation level at these promoters, highlighting the important correlation between the processing event and PfGCN5 activity. Altogether, our study reveals a unique processing event for a nuclear protein PfGCN5 with unforeseen role of a food vacuolar cysteine protease. This leads to a possibility of the development of new antimalarials against these targets.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Krishanu Bhowmick
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Ankita Tehlan
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
| | - Sunita
- School of Computational and Integrative Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Renu Sudhakar
- Centre for Cellular and Molecular Biology, Hyderabad, Telengana 500007, India
| | - Inderjeet Kaur
- International Centre for Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Puran Singh Sijwali
- Centre for Cellular and Molecular Biology, Hyderabad, Telengana 500007, India
| | | | - Suman Kumar Dhar
- Special Centre for Molecular Medicine, Jawaharlal Nehru University, New Delhi 110067, India
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15
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Dobbs KR, Crabtree JN, Dent AE. Innate immunity to malaria-The role of monocytes. Immunol Rev 2020; 293:8-24. [PMID: 31840836 PMCID: PMC6986449 DOI: 10.1111/imr.12830] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/19/2019] [Accepted: 11/25/2019] [Indexed: 12/12/2022]
Abstract
Monocytes are innate immune cells essential for host protection against malaria. Upon activation, monocytes function to help reduce parasite burden through phagocytosis, cytokine production, and antigen presentation. However, monocytes have also been implicated in the pathogenesis of severe disease through production of damaging inflammatory cytokines, resulting in systemic inflammation and vascular dysfunction. Understanding the molecular pathways influencing the balance between protection and pathology is critical. In this review, we discuss recent data regarding the role of monocytes in human malaria, including studies of innate sensing of the parasite, immunometabolism, and innate immune training. Knowledge gained from these studies may guide rational development of novel antimalarial therapies and inform vaccine development.
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Affiliation(s)
- Katherine R. Dobbs
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
- Division of Pediatric Infectious Diseases, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, OH, USA
| | - Juliet N. Crabtree
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA, USA
| | - Arlene E. Dent
- Center for Global Health and Diseases, Case Western Reserve University, Cleveland, OH, USA
- Division of Pediatric Infectious Diseases, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, OH, USA
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16
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Gupta H, Galatas B, Matambisso G, Nhamussua L, Cisteró P, Bassat Q, Casellas A, Macete E, Aponte JJ, Sacoor C, Alonso P, Saúte F, Guinovart C, Aide P, Mayor A. Differential expression of var subgroups and PfSir2a genes in afebrile Plasmodium falciparum malaria: a matched case-control study. Malar J 2019; 18:326. [PMID: 31547813 PMCID: PMC6755688 DOI: 10.1186/s12936-019-2963-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 09/13/2019] [Indexed: 12/16/2022] Open
Abstract
Background Poor knowledge on the afebrile Plasmodium falciparum biology limits elimination approaches to target asymptomatic malaria. Therefore, the association of parasite factors involved in cytoadhesion, parasite multiplication and gametocyte maturation with afebrile malaria was assessed. Methods Plasmodium falciparum isolates were collected from febrile (axillary temperature ≥ 37.5 °C or a reported fever in the previous 24 h) and afebrile (fever neither at the visit nor in the previous 24 h) individuals residing in Southern Mozambique. var, PfSir2a and Pfs25 transcript levels were determined by reverse transcriptase quantitative PCRs (RT-qPCRs) and compared among 61 pairs of isolates matched by parasite density, age and year of sample collection. Results The level of varC and PfSir2a transcripts was higher in P. falciparum isolates from afebrile individuals (P ≤ 0.006), while varB and DC8 genes (P ≤ 0.002) were higher in isolates from individuals with febrile infections. After adjusting the analysis by area of residence, doubling the relative transcript unit (RTU) of varC and PfSir2a was associated with a 29.7 (95% CI 4.6–192.3) and 8.5 (95% CI 1.9–32.2) fold increases, respectively, of the odds of being afebrile. In contrast, doubling the RTU of varB and DC8 was associated with a 0.8 (95% CI 0.05–0.6) and 0.2 (95% CI 0.04–0.6) fold changes, respectively, of the odds of being afebrile. No significant differences were found for Pfs25 transcript levels in P. falciparum isolates from afebrile and febrile individuals. Conclusions var and gametocyte-specific transcript patterns in febrile and afebrile infections from southern Mozambique matched by age, parasite density and recruitment period suggest similar transmissibility but differential expression of variant antigens involved in cytoadhesion and immune-evasion.
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Affiliation(s)
- Himanshu Gupta
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain. .,, Carrer Rosselló 153 (CEK Building), 08036, Barcelona, Spain.
| | - Beatriz Galatas
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | | | - Lidia Nhamussua
- Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Pau Cisteró
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Quique Bassat
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique.,ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain.,Pediatrics department, Hospital Sant Joan de Déu (University of Barcelona), Barcelona, Spain.,Consorcio de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Madrid, Spain
| | - Aina Casellas
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Eusébio Macete
- Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - John J Aponte
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | | | - Pedro Alonso
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Francisco Saúte
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Caterina Guinovart
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
| | - Pedro Aide
- Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique.,National Institute of Health, Ministry of Health, Maputo, Mozambique
| | - Alfredo Mayor
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.,Centro de Investigação em Saúde de Manhiça, Manhiça, Mozambique
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17
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Bachmann A, Bruske E, Krumkamp R, Turner L, Wichers JS, Petter M, Held J, Duffy MF, Sim BKL, Hoffman SL, Kremsner PG, Lell B, Lavstsen T, Frank M, Mordmüller B, Tannich E. Controlled human malaria infection with Plasmodium falciparum demonstrates impact of naturally acquired immunity on virulence gene expression. PLoS Pathog 2019; 15:e1007906. [PMID: 31295334 PMCID: PMC6650087 DOI: 10.1371/journal.ppat.1007906] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 07/23/2019] [Accepted: 06/10/2019] [Indexed: 12/14/2022] Open
Abstract
The pathogenesis of Plasmodium falciparum malaria is linked to the variant surface antigen PfEMP1, which mediates tethering of infected erythrocytes to the host endothelium and is encoded by approximately 60 var genes per parasite genome. Repeated episodes of malaria infection result in the gradual acquisition of protective antibodies against PfEMP1 variants. The antibody repertoire is believed to provide a selective pressure driving the clonal expansion of parasites expressing unrecognized PfEMP1 variants, however, due to the lack of experimental in vivo models there is only limited experimental evidence in support of this concept. To get insight into the impact of naturally acquired immunity on the expressed var gene repertoire early during infection we performed controlled human malaria infections of 20 adult African volunteers with life-long malaria exposure using aseptic, purified, cryopreserved P. falciparum sporozoites (Sanaria PfSPZ Challenge) and correlated serological data with var gene expression patterns from ex vivo parasites. Among the 10 African volunteers who developed patent infections, individuals with low antibody levels showed a steep rise in parasitemia accompanied by broad activation of multiple, predominantly subtelomeric var genes, similar to what we previously observed in naïve volunteers. In contrast, individuals with intermediate antibody levels developed asymptomatic infections and the ex vivo parasite populations expressed only few var gene variants, indicative of clonal selection. Importantly, in contrast to parasites from naïve volunteers, expression of var genes coding for endothelial protein C receptor (EPCR)-binding PfEMP1 that are associated with severe childhood malaria was rarely detected in semi-immune adult African volunteers. Moreover, we followed var gene expression for up to six parasite replication cycles and demonstrated for the first time in vivo a shift in the dominant var gene variant. In conclusion, our data suggest that P. falciparum activates multiple subtelomeric var genes at the onset of blood stage infection facilitating rapid expansion of parasite clones which express PfEMP1 variants unrecognized by the host's immune system, thus promoting overall parasite survival in the face of host immunity.
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Affiliation(s)
- Anna Bachmann
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
| | - Ellen Bruske
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Ralf Krumkamp
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
- Infectious Disease Epidemiology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Louise Turner
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen K, Denmark
| | - J. Stephan Wichers
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
| | - Michaela Petter
- Mikrobiologisches Institut–Klinische Mikrobiologie, Immunologie und Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität (FAU) Erlangen-Nürnberg, Erlangen, Germany
- School of BioSciences, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Jana Held
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Michael F. Duffy
- School of BioSciences, Bio21 Institute, University of Melbourne, Parkville, Victoria, Australia
| | | | | | - Peter G. Kremsner
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Bertrand Lell
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- German Center for Infection Research (DZIF), African partner institution, CERMEL, Gabon
| | - Thomas Lavstsen
- Centre for Medical Parasitology, University of Copenhagen, Copenhagen K, Denmark
| | - Matthias Frank
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University Hospital Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Germany
| | - Egbert Tannich
- Department of Molecular Parasitology, Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Germany
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18
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Tuju J, Mackinnon MJ, Abdi AI, Karanja H, Musyoki JN, Warimwe GM, Gitau EN, Marsh K, Bull PC, Urban BC. Antigenic cartography of immune responses to Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1). PLoS Pathog 2019; 15:e1007870. [PMID: 31260501 PMCID: PMC6625739 DOI: 10.1371/journal.ppat.1007870] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 07/12/2019] [Accepted: 05/24/2019] [Indexed: 12/15/2022] Open
Abstract
Naturally acquired clinical immunity to Plasmodium falciparum is partly mediated by antibodies directed at parasite-derived antigens expressed on the surface of red blood cells which mediate disease and are extremely diverse. Unlike children, adults recognize a broad range of variant surface antigens (VSAs) and are protected from severe disease. Though crucial to the design and feasibility of an effective malaria vaccine, it is not yet known whether immunity arises through cumulative exposure to each of many antigenic types, cross-reactivity between antigenic types, or some other mechanism. In this study, we measured plasma antibody responses of 36 children with symptomatic malaria to a diverse panel of 36 recombinant proteins comprising part of the DBLα domain (the 'DBLα-tag') of PfEMP1, a major class of VSAs. We found that although plasma antibody responses were highly specific to individual antigens, serological profiles of responses across antigens fell into one of just two distinct types. One type was found almost exclusively in children that succumbed to severe disease (19 out of 20) while the other occurred in all children with mild disease (16 out of 16). Moreover, children with severe malaria had serological profiles that were narrower in antigen specificity and shorter-lived than those in children with mild malaria. Borrowing a novel technique used in influenza-antigenic cartography-we mapped these dichotomous serological profiles to amino acid sequence variation within a small sub-region of the PfEMP1 DBLα domain. By applying our methodology on a larger scale, it should be possible to identify epitopes responsible for eliciting the protective version of serological profiles to PfEMP1 thereby accelerating development of a broadly effective anti-disease malaria vaccine.
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Affiliation(s)
- James Tuju
- KEMRI-Wellcome Trust Research Programme, Kenya
- Department of Chemistry and Biochemistry, Pwani University, Kilifi, Kenya
| | | | | | | | | | - George M. Warimwe
- KEMRI-Wellcome Trust Research Programme, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Evelyn N. Gitau
- African Population and Health Research Center, Nairobi, Kenya
| | - Kevin Marsh
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | | | - Britta C. Urban
- Liverpool School of Tropical Medicine, Department of Tropical Disease Biology, Pembroke Place, Liverpool, United Kingdom
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19
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Looker O, Blanch AJ, Liu B, Nunez-Iglesias J, McMillan PJ, Tilley L, Dixon MWA. The knob protein KAHRP assembles into a ring-shaped structure that underpins virulence complex assembly. PLoS Pathog 2019; 15:e1007761. [PMID: 31071194 PMCID: PMC6529015 DOI: 10.1371/journal.ppat.1007761] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 05/21/2019] [Accepted: 04/15/2019] [Indexed: 01/25/2023] Open
Abstract
Plasmodium falciparum mediates adhesion of infected red blood cells (RBCs) to blood vessel walls by assembling a multi-protein complex at the RBC surface. This virulence-mediating structure, called the knob, acts as a scaffold for the presentation of the major virulence antigen, P. falciparum Erythrocyte Membrane Protein-1 (PfEMP1). In this work we developed correlative STochastic Optical Reconstruction Microscopy–Scanning Electron Microscopy (STORM-SEM) to spatially and temporally map the delivery of the knob-associated histidine-rich protein (KAHRP) and PfEMP1 to the RBC membrane skeleton. We show that KAHRP is delivered as individual modules that assemble in situ, giving a ring-shaped fluorescence profile around a dimpled disk that can be visualized by SEM. Electron tomography of negatively-stained membranes reveals a previously observed spiral scaffold underpinning the assembled knobs. Truncation of the C-terminal region of KAHRP leads to loss of the ring structures, disruption of the raised disks and aberrant formation of the spiral scaffold, pointing to a critical role for KAHRP in assembling the physical knob structure. We show that host cell actin remodeling plays an important role in assembly of the virulence complex, with cytochalasin D blocking knob assembly. Additionally, PfEMP1 appears to be delivered to the RBC membrane, then inserted laterally into knob structures. The human malaria parasite Plasmodium falciparum causes severe disease, which is initiated by the adhesion of parasite-infected RBCs to receptors on the walls of the host’s capillaries. Adhesion is mediated by a structure called the knob, which acts as a scaffold for the presentation of the virulence protein, P. falciparum erythrocyte membrane protein-1 (PfEMP1). In this work we investigate the assembly of this complex at different stages of parasite development using a multimodal imaging approach that combines dSTORM localization microscopy and scanning electron microscopy (STORM-SEM). We show that the knob-associated histidine-rich protein (KAHRP) is delivered to the RBC membrane skeleton as individual protein modules that assemble into a ring-shaped complex. We provide evidence that host cell remodeling, driven by association of KAHRP with spectrin and the reorganization of actin, is required for assembly of the ring complex, which in turn supports a spiral scaffold that is required for correct knob morphology. Finally, we provide evidence that PfEMP1 is delivered to the RBC membrane before associating with knob complexes.
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Affiliation(s)
- Oliver Looker
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Adam J. Blanch
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Boyin Liu
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Juan Nunez-Iglesias
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Paul J. McMillan
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
- Biological Optical Microscopy Platform, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Leann Tilley
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
| | - Matthew W. A. Dixon
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Australia
- * E-mail:
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20
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Engel JA, Norris EL, Gilson P, Przyborski J, Shonhai A, Blatch GL, Skinner-Adams TS, Gorman J, Headlam M, Andrews KT. Proteomic analysis of Plasmodium falciparum histone deacetylase 1 complex proteins. Exp Parasitol 2019; 198:7-16. [PMID: 30682336 DOI: 10.1016/j.exppara.2019.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 12/01/2018] [Accepted: 01/20/2019] [Indexed: 01/12/2023]
Abstract
Plasmodium falciparum histone deacetylases (PfHDACs) are an important class of epigenetic regulators that alter protein lysine acetylation, contributing to regulation of gene expression and normal parasite growth and development. PfHDACs are therefore under investigation as drug targets for malaria. Despite this, our understanding of the biological roles of these enzymes is only just beginning to emerge. In higher eukaryotes, HDACs function as part of multi-protein complexes and act on both histone and non-histone substrates. Here, we present a proteomics analysis of PfHDAC1 immunoprecipitates, identifying 26 putative P. falciparum complex proteins in trophozoite-stage asexual intraerythrocytic parasites. The co-migration of two of these (P. falciparum heat shock proteins 70-1 and 90) with PfHDAC1 was validated using Blue Native PAGE combined with Western blot. These data provide a snapshot of possible PfHDAC1 interactions and a starting point for future studies focused on elucidating the broader function of PfHDACs in Plasmodium parasites.
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Affiliation(s)
- Jessica A Engel
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia
| | - Emma L Norris
- QIMR Berghofer Medical Research Institute, Queensland, Australia
| | - Paul Gilson
- Burnet Institute, Monash University, Victoria, Australia
| | - Jude Przyborski
- Centre of Infectious Diseases, Parasitology, University Hospital Heidelberg, Germany
| | - Addmore Shonhai
- Biochemistry Department, University of Venda, Thohoyandou, South Africa
| | - Gregory L Blatch
- The Vice Chancellery, The University of Notre Dame Australia, Fremantle, WA, Australia
| | - Tina S Skinner-Adams
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia
| | - Jeffrey Gorman
- QIMR Berghofer Medical Research Institute, Queensland, Australia
| | | | - Katherine T Andrews
- Griffith Institute for Drug Discovery, Griffith University, Queensland, Australia.
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21
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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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Kanyal A, Rawat M, Gurung P, Choubey D, Anamika K, Karmodiya K. Genome‐wide survey and phylogenetic analysis of histone acetyltransferases and histone deacetylases of
Plasmodium falciparum. FEBS J 2018; 285:1767-1782. [DOI: 10.1111/febs.14376] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 11/20/2017] [Accepted: 12/22/2017] [Indexed: 12/31/2022]
Affiliation(s)
- Abhishek Kanyal
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | - Mukul Rawat
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | - Pratima Gurung
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
| | | | | | - Krishanpal Karmodiya
- Department of Biology Indian Institute of Science Education and Research Pashan, Pune India
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Abstract
Protozoan parasites colonize numerous metazoan hosts and insect vectors through their life cycles, with the need to respond quickly and reversibly while encountering diverse and often hostile ecological niches. To succeed, parasites must also persist within individuals until transmission between hosts is achieved. Several parasitic protozoa cause a huge burden of disease in humans and livestock, and here we focus on the parasites that cause malaria and African trypanosomiasis. Efforts to understand how these pathogens adapt to survive in varied host environments, cause disease, and transmit between hosts have revealed a wealth of epigenetic phenomena. Epigenetic switching mechanisms appear to be ideally suited for the regulation of clonal antigenic variation underlying successful parasitism. We review the molecular players and complex mechanistic layers that mediate the epigenetic regulation of virulence gene expression. Understanding epigenetic processes will aid the development of antiparasitic therapeutics.
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Affiliation(s)
- Manoj T Duraisingh
- Department of Immunology and Infectious Diseases, Harvard T. H. Chan School of Public Health, 651 Huntington Avenue, Boston, MA 02115, USA.
| | - David Horn
- Division of Biological Chemistry & Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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Abdi AI, Hodgson SH, Muthui MK, Kivisi CA, Kamuyu G, Kimani D, Hoffman SL, Juma E, Ogutu B, Draper SJ, Osier F, Bejon P, Marsh K, Bull PC. Plasmodium falciparum malaria parasite var gene expression is modified by host antibodies: longitudinal evidence from controlled infections of Kenyan adults with varying natural exposure. BMC Infect Dis 2017; 17:585. [PMID: 28835215 PMCID: PMC5569527 DOI: 10.1186/s12879-017-2686-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 08/15/2017] [Indexed: 11/10/2022] Open
Abstract
Background The PfEMP1 family of Plasmodium falciparum antigens play a key role in pathogenesis of severe malaria through their insertion into the surface of parasite infected erythrocytes, and adhesion to host cells. Previous studies have suggested that parasites expressing PfEMP1 subclasses group A and DC8, associated with severe malaria, may have a growth advantage in immunologically naïve individuals. However, this idea has not been tested in longitudinal studies. Methods Here we assessed expression of the var genes encoding PfEMP1, in parasites sampled from volunteers with varying prior exposure to malaria, following experimental infection by sporozoites (PfSPZ). Using qPCR, we tested for associations between the expression of various var subgroups in surviving parasite populations from each volunteer and 1) the levels of participants’ antibodies to infected erythrocytes before challenge infection and 2) the apparent in vivo parasite multiplication rate. Results We show that 1) expression of var genes encoding for group A and DC8-like PfEMP1 were associated with low levels of antibodies to infected erythrocytes (αIE) before challenge, and 2) expression of a DC8-like CIDRα1.1 domain was associated with higher apparent parasite multiplication rate in a manner that was independent of levels of prior antibodies to infected erythrocytes. Conclusions This study provides insight into the role of antibodies to infected erythrocytes surface antigens in the development of naturally acquired immunity and may help explain why specific PfEMP1 variants may be associated with severe malaria. Trial registration Pan African Clinical Trial Registry: PACTR201211000433272. Date of registration: 10th October 2012.
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Affiliation(s)
- Abdirahman I Abdi
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya. .,Pwani University, P. O. Box 195-80108, Kilifi, Kenya.
| | | | - Michelle K Muthui
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | - Cheryl A Kivisi
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya.,Pwani University, P. O. Box 195-80108, Kilifi, Kenya
| | - Gathoni Kamuyu
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | - Domtila Kimani
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | | | - Elizabeth Juma
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.,Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya
| | - Bernhards Ogutu
- Centre for Clinical Research, Kenya Medical Research Institute, Nairobi, Kenya.,Centre for Research in Therapeutic Sciences, Strathmore University, Nairobi, Kenya
| | | | - Faith Osier
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | - Philip Bejon
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, CGMRC, P.O. Box 230-80108, Kilifi County, Kenya
| | - Peter C Bull
- Department of Pathology, University of Cambridge, 17 Tennis Court Road, Cambridge, CB2 1QP, UK.
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25
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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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26
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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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27
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Zeeshan M, Kaur I, Joy J, Saini E, Paul G, Kaushik A, Dabral S, Mohmmed A, Gupta D, Malhotra P. Proteomic Identification and Analysis of Arginine-Methylated Proteins of Plasmodium falciparum at Asexual Blood Stages. J Proteome Res 2017; 16:368-383. [DOI: 10.1021/acs.jproteome.5b01052] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Mohammad Zeeshan
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
- Translational
Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Inderjeet Kaur
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Joseph Joy
- Translational
Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Ekta Saini
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Gourab Paul
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | | | - Surbhi Dabral
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Asif Mohmmed
- Parasite
Cell Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Dinesh Gupta
- Translational
Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Pawan Malhotra
- Malaria
Biology Group, International Centre for Genetic Engineering and Biotechnology (ICGEB), Aruna Asaf Ali Marg, New Delhi 110067, India
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28
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Mosquito Passage Dramatically Changes var Gene Expression in Controlled Human Plasmodium falciparum Infections. PLoS Pathog 2016; 12:e1005538. [PMID: 27070311 PMCID: PMC4829248 DOI: 10.1371/journal.ppat.1005538] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/10/2016] [Indexed: 11/19/2022] Open
Abstract
Virulence of the most deadly malaria parasite Plasmodium falciparum is linked to the variant surface antigen PfEMP1, which is encoded by about 60 var genes per parasite genome. Although the expression of particular variants has been associated with different clinical outcomes, little is known about var gene expression at the onset of infection. By analyzing controlled human malaria infections via quantitative real-time PCR, we show that parasite populations from 18 volunteers expressed virtually identical transcript patterns that were dominated by the subtelomeric var gene group B and, to a lesser extent, group A. Furthermore, major changes in composition and frequency of var gene transcripts were detected between the parental parasite culture that was used to infect mosquitoes and Plasmodia recovered from infected volunteers, suggesting that P. falciparum resets its var gene expression during mosquito passage and starts with the broad expression of a specific subset of var genes when entering the human blood phase.
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Martel S, Begnaud F, Schuler W, Gillerat F, Oberhauser N, Nurisso A, Carrupt PA. Limits of rapid log P determination methods for highly lipophilic and flexible compounds. Anal Chim Acta 2016; 915:90-101. [DOI: 10.1016/j.aca.2016.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 01/31/2016] [Accepted: 02/03/2016] [Indexed: 10/22/2022]
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30
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Global selection of Plasmodium falciparum virulence antigen expression by host antibodies. Sci Rep 2016; 6:19882. [PMID: 26804201 PMCID: PMC4726288 DOI: 10.1038/srep19882] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 12/21/2015] [Indexed: 12/22/2022] Open
Abstract
Parasite proteins called PfEMP1 that are inserted on the surface of infected erythrocytes, play a key role in the severe pathology associated with infection by the Plasmodium falciparum malaria parasite. These proteins mediate binding of infected cells to the endothelial lining of blood vessels as a strategy to avoid clearance by the spleen and are major targets of naturally acquired immunity. PfEMP1 is encoded by a large multi-gene family called var. Mutually-exclusive transcriptional switching between var genes allows parasites to escape host antibodies. This study examined in detail the patterns of expression of var in a well-characterized sample of parasites from Kenyan Children. Instead of observing clear inverse relationships between the expression of broad sub-classes of PfEMP1, we found that expression of different PfEMP1 groups vary relatively independently. Parasite adaptation to host antibodies also appears to involve a general reduction in detectable var gene expression. We suggest that parasites switch both between different PfEMP1 variants and between high and low expression states. Such a strategy could provide a means of avoiding immunological detection and promoting survival under high levels of host immunity.
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31
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Abstract
The Plasmodium falciparum erythrocyte membrane protein 1 antigens that are inserted onto the surface of P. falciparum infected erythrocytes play a key role both in the pathology of severe malaria and as targets of naturally acquired immunity. They might be considered unlikely vaccine targets because they are extremely diverse. However, several lines of evidence suggest that underneath this molecular diversity there are a restricted set of epitopes which may act as effective targets for a vaccine against severe malaria. Here we review some of the recent developments in this area of research, focusing on work that has assessed the potential of these molecules as possible vaccine targets.
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32
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Galatas B, Bassat Q, Mayor A. Malaria Parasites in the Asymptomatic: Looking for the Hay in the Haystack. Trends Parasitol 2015; 32:296-308. [PMID: 26708404 DOI: 10.1016/j.pt.2015.11.015] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 11/21/2015] [Accepted: 11/24/2015] [Indexed: 12/11/2022]
Abstract
With malaria elimination back on the international agenda, programs face the challenge of targeting all Plasmodium infections, not only symptomatic cases. As asymptomatic individuals are unlikely to seek treatment, they are missed by passive surveillance while remaining infectious to mosquitoes, thus acting as silent reservoirs of transmission. To estimate the risk of asymptomatic infections in various phases of malaria elimination, we need a deeper understanding of the underlying mechanisms favoring carriage over disease, which may involve both pathogen and host factors. Here we review our current knowledge on the determinants leading to Plasmodium falciparum symptomless infections. Understanding the host-pathogen interactions that are most likely to affect transitions between malaria disease states could guide the development of tools to tackle asymptomatic carriers in elimination settings.
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Affiliation(s)
- Beatriz Galatas
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Quique Bassat
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Alfredo Mayor
- ISGlobal, Barcelona Centre for International Health Research (CRESIB), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.
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33
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Differential Plasmodium falciparum surface antigen expression among children with Malarial Retinopathy. Sci Rep 2015; 5:18034. [PMID: 26657042 PMCID: PMC4677286 DOI: 10.1038/srep18034] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/10/2015] [Indexed: 11/08/2022] Open
Abstract
Retinopathy provides a window into the underlying pathology of life-threatening malarial coma ("cerebral malaria"), allowing differentiation between 1) coma caused by sequestration of Plasmodium falciparum-infected erythrocytes in the brain and 2) coma with other underlying causes. Parasite sequestration in the brain is mediated by PfEMP1; a diverse parasite antigen that is inserted into the surface of infected erythrocytes and adheres to various host receptors. PfEMP1 sub-groups called "DC8" and "DC13" have been proposed to cause brain pathology through interactions with endothelial protein C receptor. To test this we profiled PfEMP1 gene expression in parasites from children with clinically defined cerebral malaria, who either had or did not have accompanying retinopathy. We found no evidence for an elevation of DC8 or DC13 PfEMP1 expression in children with retinopathy. However, the proportional expression of a broad subgroup of PfEMP1 called "group A" was elevated in retinopathy patients suggesting that these variants may play a role in the pathology of cerebral malaria. Interventions targeting group A PfEMP1 may be effective at reducing brain pathology.
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34
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Shanks GD. Historical review: does stress provokePlasmodium falciparumrecrudescence? Trans R Soc Trop Med Hyg 2015; 109:360-5. [DOI: 10.1093/trstmh/trv032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 04/01/2015] [Indexed: 01/13/2023] Open
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Abstract
DNA can form several secondary structures besides the classic double helix: one that has received much attention in recent years is the G-quadruplex (G4). This is a stable four-stranded structure formed by the stacking of quartets of guanine bases. Recent work has convincingly shown that G4s can form in vivo as well as in vitro and can affect both replication and transcription of DNA. They also play important roles at G-rich telomeres. Now, a spate of exciting reports has begun to reveal roles for G4 structures in virulence processes in several important microbial pathogens of humans. Interestingly, these come from a range of kingdoms—bacteria and protozoa as well as viruses—and all facilitate immune evasion in different ways. In particular, roles for G4s have been posited in the antigenic variation systems of bacteria and protozoa, as well as in the silencing of at least two major human viruses, human immunodeficiency virus (HIV) and Epstein-Barr virus (EBV). Although antigenic variation and the silencing of latent viruses are quite distinct from one another, both are routes to immune evasion and the maintenance of chronic infections. Thus, highly disparate pathogens can use G4 motifs to control DNA/RNA dynamics in ways that are relevant to common virulence phenotypes. This review explores the evidence for G4 biology in such processes across a range of important human pathogens.
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Conway DJ. Paths to a malaria vaccine illuminated by parasite genomics. Trends Genet 2015; 31:97-107. [PMID: 25620796 PMCID: PMC4359294 DOI: 10.1016/j.tig.2014.12.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/19/2014] [Accepted: 12/19/2014] [Indexed: 11/24/2022]
Abstract
Discovery of vaccine candidate antigens by parasite genome sequence analyses. Genetic crosses, linkage group selection, and functional studies on parasites. Characterizing developmental and epigenetic variation alongside allelic polymorphism. Selection by naturally acquired immune responses helps to focus vaccine design.
More human death and disease is caused by malaria parasites than by all other eukaryotic pathogens combined. As early as the sequencing of the first human genome, malaria parasite genomics was prioritized to fuel the discovery of vaccine candidate antigens. This stimulated increased research on malaria, generating new understanding of the cellular and molecular mechanisms of infection and immunity. This review of recent developments illustrates how new approaches in parasite genomics, and increasingly large amounts of data from population studies, are helping to identify antigens that are promising lead targets. Although these results have been encouraging, effective discovery and characterization need to be coupled with more innovation and funding to translate findings into newly designed vaccine products for clinical trials.
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Affiliation(s)
- David J Conway
- Pathogen Molecular Biology Department, Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK.
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37
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Coleman BI, Skillman KM, Jiang RHY, Childs LM, Altenhofen LM, Ganter M, Leung Y, Goldowitz I, Kafsack BF, Marti M, Llinás M, Buckee CO, Duraisingh MT. A Plasmodium falciparum histone deacetylase regulates antigenic variation and gametocyte conversion. Cell Host Microbe 2014; 16:177-186. [PMID: 25121747 PMCID: PMC4188636 DOI: 10.1016/j.chom.2014.06.014] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 05/06/2014] [Accepted: 06/06/2014] [Indexed: 01/20/2023]
Abstract
The asexual forms of the malaria parasite Plasmodium falciparum are adapted for chronic persistence in human red blood cells, continuously evading host immunity using epigenetically regulated antigenic variation of virulence-associated genes. Parasite survival on a population level also requires differentiation into sexual forms, an obligatory step for further human transmission. We reveal that the essential nuclear gene, P. falciparum histone deacetylase 2 (PfHda2), is a global silencer of virulence gene expression and controls the frequency of switching from the asexual cycle to sexual development. PfHda2 depletion leads to dysregulated expression of both virulence-associated var genes and PfAP2-g, a transcription factor controlling sexual conversion, and is accompanied by increases in gametocytogenesis. Mathematical modeling further indicates that PfHda2 has likely evolved to optimize the parasite's infectious period by achieving low frequencies of virulence gene expression switching and sexual conversion. This common regulation of cellular transcriptional programs mechanistically links parasite transmissibility and virulence.
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Affiliation(s)
- Bradley I. Coleman
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Kristen M. Skillman
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Rays H. Y. Jiang
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Lauren M. Childs
- Department of Epidemiology and Center for Communicable Disease Dynamics, Harvard School of Public Health, Boston MA 02115 USA
| | - Lindsey M. Altenhofen
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton NJ 08544 USA
| | - Markus Ganter
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Yvette Leung
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Ilana Goldowitz
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Björn F.C. Kafsack
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton NJ 08544 USA
| | - Matthias Marti
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
| | - Manuel Llinás
- Department of Molecular Biology and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton NJ 08544 USA
| | - Caroline O. Buckee
- Department of Epidemiology and Center for Communicable Disease Dynamics, Harvard School of Public Health, Boston MA 02115 USA
| | - Manoj T. Duraisingh
- Department of Immunology & Infectious Diseases Harvard School of Public Health, Boston, MA 02115 USA
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Computational Studies on Sirtuins from Trypanosoma cruzi: Structures, Conformations and Interactions with Phytochemicals. PLoS Negl Trop Dis 2014; 8:e2689. [PMID: 24551254 PMCID: PMC3923677 DOI: 10.1371/journal.pntd.0002689] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 12/21/2013] [Indexed: 11/19/2022] Open
Abstract
Background The silent-information regulator 2 proteins, otherwise called sirtuins, are currently considered as emerging anti-parasitic targets. Nicotinamide, a pan-sirtuin inhibitor, is known to cause kinetoplast alterations and the arrested growth of T. cruzi, the protozoan responsible for Chagas disease. These observations suggested that sirtuins from this parasite (TcSir2rp1 and TcSir2rp3) could play an important role in the regulation of the parasitic cell cycle. Thus, their inhibition could be exploited for the development of novel anti-trypanosomal compounds. Methods Homology modeling was used to determine the three-dimensional features of the sirtuin TcSir2rp1 from T. cruzi. The apo-form of human SIRT2 and the same structure solved in complex with its co-substrate NAD+ allowed the modeling of TcSir2rp1 in the open and closed conformational states. Molecular docking studies were then carried out. A library composed of fifty natural and diverse compounds that are known to be active against this parasite, was established based on the literature and virtually screened against TcSir2rp1 and TcSir2rp3, which was previously modeled by our group. Results In this study, two conformational states of TcSir2rp1 were described for the first time. The molecular docking results of compounds capable of binding sirtuins proved to be meaningful when the closed conformation of the protein was taken into account for calculations. This specific conformation was then used for the virtual screening of antritrypanosomal phytochemicals against TcSir2rp1 and TcSir2rp3. The calculations identified a limited number of scaffolds extracted from Vismia orientalis, Cussonia zimmermannii, Amomum aculeatum and Anacardium occidentale that potentially interact with both proteins. Conclusions The study provided reliable models for future structure-based drug design projects concerning sirtuins from T. cruzi. Molecular docking studies highlighted not only the advantages of performing in silico interaction studies on their closed conformations but they also suggested the potential mechanism of action of four phytochemicals known for their anti-trypanosomal activity in vitro. T. cruzi is a protozoan pathogen responsible for Chagas disease. Current therapies rely only on a very small number of drugs, most of which are inadequate because of their severe host toxicity or because of their susceptibility to drug-resistance mechanisms. To determine efficient therapeutic alternatives, the identification of new biotargets and detailed knowledge of their structures are essential. Sirtuins from T. cruzi have been recently considered as promising targets for the development of new treatments for Chagas disease. Inhibition of their activity has been shown to significantly interfere with the life cycle of the parasite. T. cruzi possesses genes encoding two sirtuin-like proteins, TcSIR2rp1 and TcSIR2rp3. The structures of these enzymes were theoretically elucidated in this work, which also focused on the impact of their possible conformational states on computational interaction studies. A small library of phytochemicals that are active against the parasite was built and screened against the most meaningful conformations, identifying a restricted number of scaffolds that potentially interact with the modeled proteins. For these hits, a mechanism of action related to interactions with sirtuins was proposed.
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Gitau EN, Tuju J, Karanja H, Stevenson L, Requena P, Kimani E, Olotu A, Kimani D, Marsh K, Bull P, Urban BC. CD4+ T cell responses to the Plasmodium falciparum erythrocyte membrane protein 1 in children with mild malaria. THE JOURNAL OF IMMUNOLOGY 2014; 192:1753-61. [PMID: 24453249 PMCID: PMC3918862 DOI: 10.4049/jimmunol.1200547] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The immune response against the variant surface Ag Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a key component of clinical immunity against malaria. We have investigated the development and maintenance of CD4+ T cell responses to a small semiconserved area of the Duffy binding–like domain (DBL)α–domain of PfEMP1, the DBLα-tag. Young children were followed up longitudinally, and parasites and PBMCs were isolated from 35 patients presenting with an acute case of uncomplicated malaria. The DBLα-tag from the PfEMP1 dominantly expressed by the homologous parasite isolate was cloned and expressed as recombinant protein. The recombinant DBLα-tag was used to activate PBMCs collected from each acute episode and from an annual cross-sectional survey performed after the acute malaria episode. In this article, we report that CD4+ T cell responses to the homologous DBLα-tag were induced in 75% of the children at the time of the acute episode and in 62% of the children at the following cross-sectional survey on average 235 d later. Furthermore, children who had induced DBLα-tag–specific CD4+IL-4+ T cells at the acute episode remained episode free for longer than children who induced other types of CD4+ T cell responses. These results suggest that a wide range of DBLα-tag–specific CD4+ T cell responses were induced in children with mild malaria and, in the case of CD4+IL-4+ T cell responses, were associated with protection from clinical episodes.
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Affiliation(s)
- Evelyn N Gitau
- KEMRI-Wellcome Trust Collaborative Programme, Centre for Geographic Medicine Coast, 80108 Kilifi, Kenya
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Joice R, Narasimhan V, Montgomery J, Sidhu AB, Oh K, Meyer E, Pierre-Louis W, Seydel K, Milner D, Williamson K, Wiegand R, Ndiaye D, Daily J, Wirth D, Taylor T, Huttenhower C, Marti M. Inferring developmental stage composition from gene expression in human malaria. PLoS Comput Biol 2013; 9:e1003392. [PMID: 24348235 PMCID: PMC3861035 DOI: 10.1371/journal.pcbi.1003392] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 10/30/2013] [Indexed: 01/12/2023] Open
Abstract
In the current era of malaria eradication, reducing transmission is critical. Assessment of transmissibility requires tools that can accurately identify the various developmental stages of the malaria parasite, particularly those required for transmission (sexual stages). Here, we present a method for estimating relative amounts of Plasmodium falciparum asexual and sexual stages from gene expression measurements. These are modeled using constrained linear regression to characterize stage-specific expression profiles within mixed-stage populations. The resulting profiles were analyzed functionally by gene set enrichment analysis (GSEA), confirming differentially active pathways such as increased mitochondrial activity and lipid metabolism during sexual development. We validated model predictions both from microarrays and from quantitative RT-PCR (qRT-PCR) measurements, based on the expression of a small set of key transcriptional markers. This sufficient marker set was identified by backward selection from the whole genome as available from expression arrays, targeting one sentinel marker per stage. The model as learned can be applied to any new microarray or qRT-PCR transcriptional measurement. We illustrate its use in vitro in inferring changes in stage distribution following stress and drug treatment and in vivo in identifying immature and mature sexual stage carriers within patient cohorts. We believe this approach will be a valuable resource for staging lab and field samples alike and will have wide applicability in epidemiological studies of malaria transmission.
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Affiliation(s)
- Regina Joice
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Vagheesh Narasimhan
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Jacqui Montgomery
- Malawi-Liverpool-Wellcome Trust Clinical Research Programme, Blantyre, Malawi
- Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Amar Bir Sidhu
- The Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Keunyoung Oh
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Evan Meyer
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Willythssa Pierre-Louis
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Karl Seydel
- College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Danny Milner
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Kim Williamson
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Roger Wiegand
- The Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Daouda Ndiaye
- Faculty of Medicine and Pharmacy, Cheikh Anta Diop University, Dakar, Senegal
| | - Johanna Daily
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, New York, United States of America
| | - Dyann Wirth
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- The Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Terrie Taylor
- College of Osteopathic Medicine, Michigan State University, East Lansing, Michigan, United States of America
- Blantyre Malaria Project, University of Malawi College of Medicine, Blantyre, Malawi
| | - Curtis Huttenhower
- Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts, United States of America
- The Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
- * E-mail: (CH); (MM)
| | - Matthias Marti
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts, United States of America
- * E-mail: (CH); (MM)
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Duffy MF, Selvarajah SA, Josling GA, Petter M. Epigenetic regulation of the Plasmodium falciparum genome. Brief Funct Genomics 2013; 13:203-16. [PMID: 24326119 DOI: 10.1093/bfgp/elt047] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Recent research has highlighted some unique aspects of chromatin biology in the malaria parasite Plasmodium falciparum. During its erythrocytic lifecycle P. falciparum maintains its genome primarily as unstructured euchromatin. Indeed there is no clear role for chromatin-mediated silencing of the majority of the developmentally expressed genes in P. falciparum. However discontinuous stretches of heterochromatin are critical for variegated expression of contingency genes that mediate key pathogenic processes in malaria. These range from invasion of erythrocytes and antigenic variation to solute transport and growth adaptation in response to environmental changes. Despite lack of structure within euchromatin the nucleus maintains functional compartments that regulate expression of many genes at the nuclear periphery, particularly genes with clonally variant expression. The typical components of the chromatin regulatory machinery are present in P. falciparum; however, some of these appear to have evolved novel species-specific functions, e.g. the dynamic regulation of histone variants at virulence gene promoters. The parasite also appears to have repeatedly acquired chromatin regulatory proteins through lateral transfer from endosymbionts and from the host. P. falciparum chromatin regulators have been successfully targeted with multiple drugs in laboratory studies; hopefully their functional divergence from human counterparts will allow the development of parasite-specific inhibitors.
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Spleen-dependent regulation of antigenic variation in malaria parasites: Plasmodium knowlesi SICAvar expression profiles in splenic and asplenic hosts. PLoS One 2013; 8:e78014. [PMID: 24205067 PMCID: PMC3799730 DOI: 10.1371/journal.pone.0078014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 09/16/2013] [Indexed: 02/04/2023] Open
Abstract
Background Antigenic variation by malaria parasites was first described in Plasmodium knowlesi, which infects humans and macaque monkeys, and subsequently in P. falciparum, the most virulent human parasite. The schizont-infected cell agglutination (SICA) variant proteins encoded by the SICAvar multigene family in P. knowlesi, and Erythrocyte Membrane Protein-1 (EMP-1) antigens encoded by the var multigene family in P. falciparum, are expressed at the surface of infected erythrocytes, are associated with virulence, and serve as determinants of naturally acquired immunity. A parental P. knowlesi clone, Pk1(A+), and a related progeny clone, Pk1(B+)1+, derived by an invivo induced variant antigen switch, were defined by the expression of distinct SICA variant protein doublets of 210/190 and 205/200 kDa, respectively. Passage of SICA[+] infected erythrocytes through splenectomized rhesus monkeys results in the SICA[-] phenotype, defined by the lack of surface expression and agglutination with variant specific antisera. Principal Findings We have investigated SICAvar RNA and protein expression in Pk1(A+), Pk1(B+)1+, and SICA[-] parasites. The Pk1(A+) and Pk1(B+)1+ parasites express different distinct SICAvar transcript and protein repertoires. By comparison, SICA[-] parasites are characterized by a vast reduction in SICAvar RNA expression, the lack of full-length SICAvar transcript signals on northern blots, and correspondingly, the absence of any SICA protein detected by mass spectrometry. Significance SICA protein expression may be under transcriptional as well as post-transcriptional control, and we show for the first time that the spleen, an organ central to blood-stage immunity in malaria, exerts an influence on these processes. Furthermore, proteomics has enabled the first in-depth characterization of SICA[+] protein phenotypes and we show that the invivo switch from Pk1(A+) to Pk1(B+)1+ parasites resulted in a complete change in SICA profiles. These results emphasize the importance of studying antigenic variation in the context of the host environment.
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Warimwe GM, Recker M, Kiragu EW, Buckee CO, Wambua J, Musyoki JN, Marsh K, Bull PC. Plasmodium falciparum var gene expression homogeneity as a marker of the host-parasite relationship under different levels of naturally acquired immunity to malaria. PLoS One 2013; 8:e70467. [PMID: 23922996 PMCID: PMC3726600 DOI: 10.1371/journal.pone.0070467] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 06/19/2013] [Indexed: 11/19/2022] Open
Abstract
Acquired immunity to Plasmodium falciparum infection causes a change from frequent, sometimes life-threatening, malaria in young children to asymptomatic, chronic infections in older children and adults. Little is known about how this transition occurs but antibodies to the extremely diverse PfEMP1 parasite antigens are thought to play a role. PfEMP1 is encoded by a family of 60 var genes that undergo clonal antigenic variation, potentially creating an antigenically heterogeneous infecting population of parasites within the host. Previous theoretical work suggests that antibodies to PfEMP1 may play a role in "orchestrating" their expression within infections leading to sequential, homogeneous expression of var genes, and prolonged infection chronicity. Here, using a cloning and sequencing approach we compare the var expression homogeneity (VEH) between isolates from children with asymptomatic and clinical infections. We show that asymptomatic infections have higher VEH than clinical infections and a broader host antibody response. We discuss this in relation to the potential role of host antibodies in promoting chronicity of infection and parasite survival through the low transmission season.
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Affiliation(s)
- George M. Warimwe
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- The Jenner Institute, University of Oxford, Oxford, United Kingdom
| | - Mario Recker
- Department of Zoology, University of Oxford, Oxford, United Kingdom
| | - Esther W. Kiragu
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Caroline O. Buckee
- Department of Epidemiology, Harvard School of Public Health, Boston, Massachusetts, United States of America
| | - Juliana Wambua
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Jennifer N. Musyoki
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
| | - Kevin Marsh
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
| | - Peter C. Bull
- Pathogen, Vector and Human Biology Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Guizetti J, Scherf A. Silence, activate, poise and switch! Mechanisms of antigenic variation in Plasmodium falciparum. Cell Microbiol 2013; 15:718-26. [PMID: 23351305 PMCID: PMC3654561 DOI: 10.1111/cmi.12115] [Citation(s) in RCA: 112] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/11/2013] [Accepted: 01/14/2013] [Indexed: 12/17/2022]
Abstract
Phenotypic variation in genetically identical malaria parasites is an emerging topic. Although antigenic variation is only part of a more global parasite strategy to create adaptation through epigenetically controlled transcriptional variability, it is the central mechanism enabling immune evasion and promoting pathogenesis. The var gene family is the best-studied example in a wide range of clonally variant gene families in Plasmodium falciparum. It is unique in its strict selection of a single member for activation, a process termed monoallelic expression. The conceptual advances that have emerged from studying var genes show striking common epigenetic features with many other clonally variant gene families or even single-copy genes that show a variegated expression in parasite populations. However, major mechanistic questions, such as the existence of a potential expression site and the identity of transcription factors or genetic elements driving singular gene choice, are still unanswered. In this review we discuss the recent findings in the molecular processes essential for clonal variation, namely silencing, activation, poising and switching. Integrating findings about all clonally variant gene families and other mutually exclusive expression systems will hopefully drive mechanistic understanding of antigenic variation.
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Affiliation(s)
- Julien Guizetti
- Unité de Biologie des Interactions Hôte-Parasite, Département de Parasitologie et Mycologie, Institut Pasteur, 25 Rue du Dr. Roux, Cedex 15, F-75724 Paris, France
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Religa AA, Waters AP. Sirtuins of parasitic protozoa: in search of function(s). Mol Biochem Parasitol 2012; 185:71-88. [PMID: 22906508 PMCID: PMC3484402 DOI: 10.1016/j.molbiopara.2012.08.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 08/01/2012] [Accepted: 08/02/2012] [Indexed: 01/09/2023]
Abstract
The SIR2 family of NAD+-dependent protein deacetylases, collectively called sirtuins, has been of central interest due to their proposed roles in life-span regulation and ageing. Sirtuins are one group of environment sensors of a cell interpreting external information and orchestrating internal responses at the sub-cellular level, through participation in gene regulation mechanisms. Remarkably conserved across all kingdoms of life SIR2 proteins in several protozoan parasites appear to have both conserved and intriguing unique functions. This review summarises our current knowledge of the members of the sirtuin families in Apicomplexa, including Plasmodium, and other protozoan parasites such as Trypanosoma and Leishmania. The wide diversity of processes regulated by SIR2 proteins makes them targets worthy of exploitation in anti-parasitic therapies.
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Affiliation(s)
- Agnieszka A Religa
- Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow G12 8TA, UK.
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