1
|
Haese-Hill W, Crouch K, Otto TD. Annotation and visualization of parasite, fungi and arthropod genomes with Companion. Nucleic Acids Res 2024; 52:W39-W44. [PMID: 38752499 PMCID: PMC11223846 DOI: 10.1093/nar/gkae378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/06/2024] [Accepted: 04/30/2024] [Indexed: 07/06/2024] Open
Abstract
As sequencing genomes has become increasingly popular, the need for annotation of the resulting assemblies is growing. Structural and functional annotation is still challenging as it includes finding the correct gene sequences, annotating other elements such as RNA and being able to submit those data to databases to share it with the community. Compared to de novo assembly where contiguous chromosomes are a sign of high quality, it is difficult to visualize and assess the quality of annotation. We developed the Companion web server to allow non-experts to annotate their genome using a reference-based method, enabling them to assess the output before submitting to public databases. In this update paper, we describe how we have included novel methods for gene finding and made the Companion server more efficient for annotation of genomes of up to 1 Gb in size. The reference set was increased to include genomes of interest for human and animal health from the fungi and arthropod kingdoms. We show that Companion outperforms existing comparable tools where closely related references are available.
Collapse
Affiliation(s)
| | - Kathryn Crouch
- School of Infection & Immunity, University of Glasgow, UK
| | - Thomas D Otto
- School of Infection & Immunity, University of Glasgow, UK
- LPHI, CNRS, INSERM, Université de Montpellier, France
| |
Collapse
|
2
|
Gupta A, Gonzalez-Chavez Z, Desai SA. Plasmodium falciparum CLAG Paralogs All Traffic to the Host Membrane but Knockouts Have Distinct Phenotypes. Microorganisms 2024; 12:1172. [PMID: 38930554 PMCID: PMC11205492 DOI: 10.3390/microorganisms12061172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 06/04/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
Malaria parasites increase their host erythrocyte's permeability to obtain essential nutrients from plasma and facilitate intracellular growth. In the human Plasmodium falciparum pathogen, this increase is mediated by the plasmodial surface anion channel (PSAC) and has been linked to CLAG3, a protein integral to the host erythrocyte membrane and encoded by a member of the conserved clag multigene family. Whether paralogs encoded by other clag genes also insert at the host membrane is unknown; their contributions to PSAC formation and other roles served are also unexplored. Here, we generated transfectant lines carrying epitope-tagged versions of each CLAG. Each paralog is colocalized with CLAG3, with concordant trafficking via merozoite rhoptries to the host erythrocyte membrane of newly invaded erythrocytes. Each also exists within infected cells in at least two forms: an alkaline-extractable soluble form and a form integral to the host membrane. Like CLAG3, CLAG2 has a variant region cleaved by extracellular proteases, but CLAG8 and CLAG9 are protease resistant. Paralog knockout lines, generated through CRISPR/Cas9 transfection, exhibited uncompromised growth in PGIM, a modified medium with higher physiological nutrient levels; this finding is in marked contrast to a recently reported CLAG3 knockout parasite. CLAG2 and CLAG8 knockout lines exhibited compensatory increases in the transcription of the remaining clags and associated rhoph genes, yielding increased PSAC-mediated uptake for specific solutes. We also report on the distinct transport properties of these knockout lines. Similar membrane topologies at the host membrane are consistent with each CLAG paralog contributing to PSAC, but other roles require further examination.
Collapse
Affiliation(s)
| | | | - Sanjay A. Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MA 20852, USA
| |
Collapse
|
3
|
Sohail A, Barry A, Auburn S, Cheng Q, Lau CL, Lee R, Price RN, Furuya-Kanamori L, Bareng P, McGuinness SL, Leder K. Imported malaria into Australia: surveillance insights and opportunities. J Travel Med 2024; 31:taad164. [PMID: 38127641 PMCID: PMC10998534 DOI: 10.1093/jtm/taad164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 12/23/2023]
Abstract
BACKGROUND Malaria continues to pose a significant burden in endemic countries, many of which lack access to molecular surveillance. Insights from malaria cases in travellers returning to non-endemic areas can provide valuable data to inform endemic country programmes. To evaluate the potential for novel global insights into malaria, we examined epidemiological and molecular data from imported malaria cases to Australia. METHODS We analysed malaria cases reported in Australia from 2012 to 2022 using National Notifiable Disease Surveillance System data. Molecular data on imported malaria cases were obtained from literature searches. RESULTS Between 2012 and 2022, 3204 malaria cases were reported in Australia. Most cases (69%) were male and 44% occurred in young adults aged 20-39 years. Incidence rates initially declined between 2012 and 2015, then increased until 2019. During 2012-2019, the incidence in travellers ranged from 1.34 to 7.71 per 100 000 trips. Cases were primarily acquired in Sub-Saharan Africa (n = 1433; 45%), Oceania (n = 569; 18%) and Southern and Central Asia (n = 367; 12%). The most common countries of acquisition were Papua New Guinea (n = 474) and India (n = 277). Plasmodium falciparum accounted for 58% (1871/3204) of cases and was predominantly acquired in Sub-Saharan Africa, and Plasmodium vivax accounted for 32% (1016/3204), predominantly from Oceania and Asia. Molecular studies of imported malaria cases to Australia identified genetic mutations and deletions associated with drug resistance and false-negative rapid diagnostic test results, and led to the establishment of reference genomes for P. vivax and Plasmodium malariae. CONCLUSIONS Our analysis highlights the continuing burden of imported malaria into Australia. Molecular studies have offered valuable insights into drug resistance and diagnostic limitations, and established reference genomes. Integrating molecular data into national surveillance systems could provide important infectious disease intelligence to optimize treatment guidelines for returning travellers and support endemic country surveillance programmes.
Collapse
Affiliation(s)
- Asma Sohail
- School of Public Health and Preventive Medicine, Monash University, Melbourne 3004, Australia
- Department of Infectious Diseases, Grampians Health, Ballarat 3350, Australia
| | - Alyssa Barry
- Institute for Physical and Mental Health and Clinical Translation (IMPACT) and School of Medicine, Deakin University, Geelong 3220, Australia
- Disease Elimination Program, Burnet Institute, Melbourne 3004, Australia
| | - Sarah Auburn
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin 0800, Australia
| | - Qin Cheng
- Drug Resistance and Diagnostics, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane 4051, Australia
| | - Colleen L Lau
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston 4006, Australia
| | - Rogan Lee
- Parasitology Unit, Institute of Clinical Pathology and Medical Research, Sydney 2145, Australia
| | - Ric N Price
- Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin 0800, Australia
- Centre for Tropical Medicine and Global Health, Nuffield Department of Clinical Medicine, University of Oxford, Oxford OX1 2JD, UK
| | - Luis Furuya-Kanamori
- School of Public Health, Faculty of Medicine, The University of Queensland, Herston 4006, Australia
| | - Paolo Bareng
- Institute for Physical and Mental Health and Clinical Translation (IMPACT) and School of Medicine, Deakin University, Geelong 3220, Australia
| | - Sarah L McGuinness
- School of Public Health and Preventive Medicine, Monash University, Melbourne 3004, Australia
- Department of Infectious Diseases, Alfred Health, Melbourne 3004, Australia
| | - Karin Leder
- School of Public Health and Preventive Medicine, Monash University, Melbourne 3004, Australia
- Victorian Infectious Diseases Service, Melbourne Health, Melbourne 3052, Australia
| |
Collapse
|
4
|
Agyabeng-Dadzie F, Xiao R, Kissinger JC. Cryptosporidium Genomics - Current Understanding, Advances, and Applications. CURRENT TROPICAL MEDICINE REPORTS 2024; 11:92-103. [PMID: 38813571 PMCID: PMC11130048 DOI: 10.1007/s40475-024-00318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/26/2024] [Indexed: 05/31/2024]
Abstract
Purpose of Review Here we highlight the significant contribution that genomics-based approaches have had on the field of Cryptosporidium research and the insights these approaches have generated into Cryptosporidium biology and transmission. Recent Findings There are advances in genomics, genetic manipulation, gene expression, and single-cell technologies. New and better genome sequences have revealed variable sub-telomeric gene families and genes under selection. RNA expression data now include single-cell and post-infection time points. These data have provided insights into the Cryptosporidium life cycle and host-pathogen interactions. Antisense and ncRNA transcripts are abundant. The critical role of the dsRNA virus is becoming apparent. Summary The community's ability to identify genomic targets in the abundant, yet still lacking, collection of genomic data, combined with their increased ability to assess function via gene knock-out, is revolutionizing the field. Advances in the detection of virulence genes, surveillance, population genomics, recombination studies, and epigenetics are upon us.
Collapse
Affiliation(s)
| | - Rui Xiao
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602 USA
| | - Jessica C. Kissinger
- Department of Genetics, University of Georgia, Athens, GA 30602 USA
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602 USA
- Center for Tropical and Emerging Global Diseases, University of Georgia, Coverdell Center, 107, 500 D.W. Brooks Drive, Athens, GA 30602 USA
| |
Collapse
|
5
|
Florini F, Visone JE, Hadjimichael E, Malpotra S, Nötzel C, Kafsack BF, Deitsch KW. Transcriptional plasticity of virulence genes provides malaria parasites with greater adaptive capacity for avoiding host immunity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.08.584127. [PMID: 38496509 PMCID: PMC10942408 DOI: 10.1101/2024.03.08.584127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Chronic, asymptomatic malaria infections contribute substantially to disease transmission and likely represent the most significant impediment preventing malaria elimination and eradication. Plasmodium falciparum parasites evade antibody recognition through transcriptional switching between members of the var gene family, which encodes the major virulence factor and surface antigen on infected red blood cells. This process can extend infections for up to a year; however, infections have been documented to last for over a decade, constituting an unseen reservoir of parasites that undermine eradication and control efforts. How parasites remain immunologically "invisible" for such lengthy periods is entirely unknown. Here we show that in addition to the accepted paradigm of mono-allelic var gene expression, individual parasites can simultaneously express multiple var genes or enter a state in which little or no var gene expression is detectable. This unappreciated flexibility provides parasites with greater adaptive capacity than previously understood and challenges the dogma of mutually exclusive var gene expression. It also provides an explanation for the antigenically "invisible" parasites observed in chronic asymptomatic infections.
Collapse
Affiliation(s)
| | | | - Evi Hadjimichael
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Shivali Malpotra
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | | | - Björn F.C. Kafsack
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| | - Kirk W. Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York, USA
| |
Collapse
|
6
|
de Cesare M, Mwenda M, Jeffreys AE, Chirwa J, Drakeley C, Schneider K, Mambwe B, Glanz K, Ntalla C, Carrasquilla M, Portugal S, Verity RJ, Bailey JA, Ghinai I, Busby GB, Hamainza B, Hawela M, Bridges DJ, Hendry JA. Flexible and cost-effective genomic surveillance of P. falciparum malaria with targeted nanopore sequencing. Nat Commun 2024; 15:1413. [PMID: 38360754 PMCID: PMC10869361 DOI: 10.1038/s41467-024-45688-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 01/31/2024] [Indexed: 02/17/2024] Open
Abstract
Genomic surveillance of Plasmodium falciparum malaria can provide policy-relevant information about antimalarial drug resistance, diagnostic test failure, and the evolution of vaccine targets. Yet the large and low complexity genome of P. falciparum complicates the development of genomic methods, while resource constraints in malaria endemic regions can limit their deployment. Here, we demonstrate an approach for targeted nanopore sequencing of P. falciparum from dried blood spots (DBS) that enables cost-effective genomic surveillance of malaria in low-resource settings. We release software that facilitates flexible design of amplicon sequencing panels and use this software to design two target panels for P. falciparum. The panels generate 3-4 kbp reads for eight and sixteen targets respectively, covering key drug-resistance associated genes, diagnostic test antigens, polymorphic markers and the vaccine target csp. We validate our approach on mock and field samples, demonstrating robust sequencing coverage, accurate variant calls within coding sequences, the ability to explore P. falciparum within-sample diversity and to detect deletions underlying rapid diagnostic test failure.
Collapse
Affiliation(s)
- Mariateresa de Cesare
- Nuffield Department of Medicine, University of Oxford, Wellcome Centre for Human Genetics, Oxford, UK
| | | | - Anna E Jeffreys
- Nuffield Department of Medicine, University of Oxford, Wellcome Centre for Human Genetics, Oxford, UK
| | - Jacob Chirwa
- National Malaria Elimination Centre, Chainama, Lusaka, Zambia
| | | | | | | | - Karolina Glanz
- Max Planck Institute for Infection Biology, Berlin, Germany
| | | | | | | | | | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine and Center for Computational Molecular Biology, Brown University, Providence, RI, USA
| | - Isaac Ghinai
- Nuffield Department of Medicine, University of Oxford, Wellcome Centre for Human Genetics, Oxford, UK
| | - George B Busby
- Nuffield Department of Medicine, University of Oxford, Wellcome Centre for Human Genetics, Oxford, UK
| | - Busiku Hamainza
- National Malaria Elimination Centre, Chainama, Lusaka, Zambia
| | - Moonga Hawela
- National Malaria Elimination Centre, Chainama, Lusaka, Zambia
| | | | - Jason A Hendry
- Nuffield Department of Medicine, University of Oxford, Wellcome Centre for Human Genetics, Oxford, UK.
- Max Planck Institute for Infection Biology, Berlin, Germany.
| |
Collapse
|
7
|
Ruybal-Pesántez S, McCann K, Vibin J, Siegel S, Auburn S, Barry AE. Molecular markers for malaria genetic epidemiology: progress and pitfalls. Trends Parasitol 2024; 40:147-163. [PMID: 38129280 DOI: 10.1016/j.pt.2023.11.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 11/13/2023] [Accepted: 11/14/2023] [Indexed: 12/23/2023]
Abstract
Over recent years, progress in molecular markers for genotyping malaria parasites has enabled informative studies of epidemiology and transmission dynamics. Results have highlighted the value of these tools for surveillance to support malaria control and elimination strategies. There are many different types and panels of markers available for malaria parasite genotyping, and for end users, the nuances of these markers with respect to 'use case', resolution, and accuracy, are not well defined. This review clarifies issues surrounding different molecular markers and their application to malaria control and elimination. We describe available marker panels, use cases, implications for different transmission settings, limitations, access, cost, and data accuracy. The information provided can be used as a guide for molecular epidemiology and surveillance of malaria.
Collapse
Affiliation(s)
- Shazia Ruybal-Pesántez
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK; Institute of Microbiology, Universidad San Francisco de Quito, Quito, Ecuador
| | - Kirsty McCann
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; Centre for Innovation in Infectious Disease and Immunology Research (CIIDIR), Institute for Mental and Physical Health and Clinical Translation (IMPACT) and School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Jessy Vibin
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; Centre for Innovation in Infectious Disease and Immunology Research (CIIDIR), Institute for Mental and Physical Health and Clinical Translation (IMPACT) and School of Medicine, Deakin University, Geelong, Victoria, Australia
| | | | - Sarah Auburn
- Menzies School of Health Research and Charles Darwin University, Darwin, Northern Territory, Australia; Mahidol-Oxford Tropical Medicine Research Unit, Mahidol University, Bangkok, Thailand
| | - Alyssa E Barry
- Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia; Centre for Innovation in Infectious Disease and Immunology Research (CIIDIR), Institute for Mental and Physical Health and Clinical Translation (IMPACT) and School of Medicine, Deakin University, Geelong, Victoria, Australia.
| |
Collapse
|
8
|
De Meulenaere K, Cuypers WL, Gauglitz JM, Guetens P, Rosanas-Urgell A, Laukens K, Cuypers B. Selective whole-genome sequencing of Plasmodium parasites directly from blood samples by nanopore adaptive sampling. mBio 2024; 15:e0196723. [PMID: 38054750 PMCID: PMC10790762 DOI: 10.1128/mbio.01967-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/20/2023] [Indexed: 12/07/2023] Open
Abstract
IMPORTANCE Malaria is caused by parasites of the genus Plasmodium, and reached a global disease burden of 247 million cases in 2021. To study drug resistance mutations and parasite population dynamics, whole-genome sequencing of patient blood samples is commonly performed. However, the predominance of human DNA in these samples imposes the need for time-consuming laboratory procedures to enrich Plasmodium DNA. We used the Oxford Nanopore Technologies' adaptive sampling feature to circumvent this problem and enrich Plasmodium reads directly during the sequencing run. We demonstrate that adaptive nanopore sequencing efficiently enriches Plasmodium reads, which simplifies and shortens the timeline from blood collection to parasite sequencing. In addition, we show that the obtained data can be used for monitoring genetic markers, or to generate nearly complete genomes. Finally, owing to its inherent mobility, this technology can be easily applied on-site in endemic areas where patients would benefit the most from genomic surveillance.
Collapse
Affiliation(s)
- Katlijn De Meulenaere
- Department of Computer Science, Adrem Data Lab, University of Antwerp, Wilrijk, Belgium
- Department of Biomedical Sciences, Malariology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Wim L. Cuypers
- Department of Computer Science, Adrem Data Lab, University of Antwerp, Wilrijk, Belgium
| | - Julia M. Gauglitz
- Department of Computer Science, Adrem Data Lab, University of Antwerp, Wilrijk, Belgium
| | - Pieter Guetens
- Department of Biomedical Sciences, Malariology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Malariology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Kris Laukens
- Department of Computer Science, Adrem Data Lab, University of Antwerp, Wilrijk, Belgium
- Excellence centre for Microbial Systems Technology, University of Antwerp, Wilrijk, Belgium
| | - Bart Cuypers
- Department of Computer Science, Adrem Data Lab, University of Antwerp, Wilrijk, Belgium
- Excellence centre for Microbial Systems Technology, University of Antwerp, Wilrijk, Belgium
| |
Collapse
|
9
|
Thomson-Luque R, Stabler TC, Fürle K, Silva JC, Daubenberger C. Plasmodium falciparum merozoite surface protein 1 as asexual blood stage malaria vaccine candidate. Expert Rev Vaccines 2024; 23:160-173. [PMID: 38100310 DOI: 10.1080/14760584.2023.2295430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 12/12/2023] [Indexed: 12/17/2023]
Abstract
INTRODUCTION Malaria represents a public health challenge in tropical and subtropical regions, and currently deployed control strategies are likely insufficient to drive elimination of malaria. Development and improvement of malaria vaccines might be key to reduce disease burden. Vaccines targeting asexual blood stages of the parasite have shown limited efficacy when studied in human trials conducted over the past decades. AREAS COVERED Vaccine candidates based on the merozoite surface protein 1 (MSP1) were initially envisioned as one of the most promising approaches to provide immune protection against asexual blood-stage malaria. Successful immunization studies in monkey involved the use of the full-length MSP1 (MSP1FL) as vaccine construct. Vaccines using MSP1FL for immunization have the potential benefit of including numerous conserved B-cell and T-cell epitopes. This could result in improved parasite strain-transcending, protective immunity in the field. We review outcomes of clinical trials that utilized a variety of MSP1 constructs and formulations, including MSP1FL, either alone or in combination with other antigens, in both animal models and humans. EXPERT OPINION Novel approaches to analyze breadth and magnitude of effector functions of MSP1-targeting antibodies in volunteers undergoing experimental vaccination and controlled human malaria infection will help to define correlates of protective immunity.
Collapse
Affiliation(s)
- Richard Thomson-Luque
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
- Sumaya-Biotech GmbH & Co. KG Heidelberg, Germany
| | - Thomas C Stabler
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
| | - Kristin Fürle
- Centre for Infectious Diseases-Parasitology, Heidelberg University Hospital, Heidelberg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
- Global Health and Tropical Medicine, Instituto de Higiene e Medicina Tropical, Universidade NOVA de Lisboa (GHTM IHMT, UNL), Lisbon, Portugal
| | - Claudia Daubenberger
- University of Basel Basel, Switzerland
- Swiss Tropical and Public Health Institute Allschwil, Switzerland
| |
Collapse
|
10
|
Girgis ST, Adika E, Nenyewodey FE, Senoo Jnr DK, Ngoi JM, Bandoh K, Lorenz O, van de Steeg G, Harrott AJR, Nsoh S, Judge K, Pearson RD, Almagro-Garcia J, Saiid S, Atampah S, Amoako EK, Morang'a CM, Asoala V, Adjei ES, Burden W, Roberts-Sengier W, Drury E, Pierce ML, Gonçalves S, Awandare GA, Kwiatkowski DP, Amenga-Etego LN, Hamilton WL. Drug resistance and vaccine target surveillance of Plasmodium falciparum using nanopore sequencing in Ghana. Nat Microbiol 2023; 8:2365-2377. [PMID: 37996707 PMCID: PMC10686832 DOI: 10.1038/s41564-023-01516-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 10/06/2023] [Indexed: 11/25/2023]
Abstract
Malaria results in over 600,000 deaths annually, with the highest burden of deaths in young children living in sub-Saharan Africa. Molecular surveillance can provide important information for malaria control policies, including detection of antimalarial drug resistance. However, genome sequencing capacity in malaria-endemic countries is limited. We designed and implemented an end-to-end workflow to detect Plasmodium falciparum antimalarial resistance markers and diversity in the vaccine target circumsporozoite protein (csp) using nanopore sequencing in Ghana. We analysed 196 clinical samples and showed that our method is rapid, robust, accurate and straightforward to implement. Importantly, our method could be applied to dried blood spot samples, which are readily collected in endemic settings. We report that P. falciparum parasites in Ghana are mostly susceptible to chloroquine, with persistent sulfadoxine-pyrimethamine resistance and no evidence of artemisinin resistance. Multiple single nucleotide polymorphisms were identified in csp, but their significance is uncertain. Our study demonstrates the feasibility of nanopore sequencing for malaria genomic surveillance in endemic countries.
Collapse
Affiliation(s)
- Sophia T Girgis
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Edem Adika
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Felix E Nenyewodey
- Navrongo Health Research Centre (NHRC), Ghana Health Service, Navrongo, Upper East Region, Ghana
| | - Dodzi K Senoo Jnr
- Navrongo Health Research Centre (NHRC), Ghana Health Service, Navrongo, Upper East Region, Ghana
| | - Joyce M Ngoi
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Kukua Bandoh
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Oliver Lorenz
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Guus van de Steeg
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | | | - Sebastian Nsoh
- Navrongo Health Research Centre (NHRC), Ghana Health Service, Navrongo, Upper East Region, Ghana
| | - Kim Judge
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Richard D Pearson
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | | | - Samirah Saiid
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Solomon Atampah
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Enock K Amoako
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Collins M Morang'a
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | - Victor Asoala
- Navrongo Health Research Centre (NHRC), Ghana Health Service, Navrongo, Upper East Region, Ghana
| | - Elrmion S Adjei
- Ledzokuku Krowor Municipal Assembly (LEKMA) Hospital, Accra, Ghana
| | - William Burden
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | | | - Eleanor Drury
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Megan L Pierce
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Sónia Gonçalves
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana
| | | | - Lucas N Amenga-Etego
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), College of Basic and Applied Sciences, University of Ghana, Legon, Ghana.
| | - William L Hamilton
- Wellcome Sanger Institute, Wellcome Trust Genome Campus, Hinxton, UK.
- Department of Medicine, University of Cambridge, Cambridge, UK.
- Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK.
| |
Collapse
|
11
|
Tan MH, Tiedje KE, Feng Q, Zhan Q, Pascual M, Shim H, Chan YB, Day KP. A paradoxical population structure of var DBLα types in Africa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.05.565723. [PMID: 37986738 PMCID: PMC10659346 DOI: 10.1101/2023.11.05.565723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The var multigene family encodes the P. falciparum erythrocyte membrane protein 1 (PfEMP1), which is important in host-parasite interaction as a virulence factor and major surface antigen of the blood stages of the parasite, responsible for maintaining chronic infection. Whilst important in the biology of P. falciparum, these genes (50 to 60 genes per parasite genome) are routinely excluded from whole genome analyses due to their hyper-diversity, achieved primarily through recombination. The PfEMP1 head structure almost always consists of a DBLα-CIDR tandem. Categorised into different groups (upsA, upsB, upsC), different head structures have been associated with different ligand-binding affinities and disease severities. We study how conserved individual DBLα types are at the country, regional, and local scales in Sub-Saharan Africa. Using publicly-available sequence datasets and a novel ups classification algorithm, cUps, we performed an in silico exploration of DBLα conservation through time and space in Africa. In all three ups groups, the population structure of DBLα types in Africa consists of variants occurring at rare, low, moderate, and high frequencies. Non-rare variants were found to be temporally stable in a local area in endemic Ghana. When inspected across different geographical scales, we report different levels of conservation; while some DBLα types were consistently found in high frequencies in multiple African countries, others were conserved only locally, signifying local preservation of specific types. Underlying this population pattern is the composition of DBLα types within each isolate DBLα repertoire, revealed to also consist of a mix of types found at rare, low, moderate, and high frequencies in the population. We further discuss the adaptive forces and balancing selection, including host genetic factors, potentially shaping the evolution and diversity of DBLα types in Africa.
Collapse
Affiliation(s)
- Mun Hua Tan
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
| | - Kathryn E Tiedje
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
| | - Qian Feng
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Qi Zhan
- Department of Ecology and Evolution, University of Chicago; Chicago, Illinois, USA
| | - Mercedes Pascual
- Department of Ecology and Evolution, University of Chicago; Chicago, Illinois, USA
| | - Heejung Shim
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Yao-Ban Chan
- School of Mathematics and Statistics / Melbourne Integrative Genomics, The University of Melbourne, Melbourne, Australia
| | - Karen P Day
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute and Peter Doherty Institute, Melbourne, AU
| |
Collapse
|
12
|
Coonahan E, Gage H, Chen D, Noormahomed EV, Buene TP, Mendes de Sousa I, Akrami K, Chambal L, Schooley RT, Winzeler EA, Cowell AN. Whole-genome surveillance identifies markers of Plasmodium falciparum drug resistance and novel genomic regions under selection in Mozambique. mBio 2023; 14:e0176823. [PMID: 37750720 PMCID: PMC10653802 DOI: 10.1128/mbio.01768-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 09/27/2023] Open
Abstract
IMPORTANCE Malaria is a devastating disease caused by Plasmodium parasites. The evolution of parasite drug resistance continues to hamper progress toward malaria elimination, and despite extensive efforts to control malaria, it remains a leading cause of death in Mozambique and other countries in the region. The development of successful vaccines and identification of molecular markers to track drug efficacy are essential for managing the disease burden. We present an analysis of the parasite genome in Mozambique, a country with one of the highest malaria burdens globally and limited available genomic data, revealing current selection pressure. We contribute additional evidence to limited prior studies supporting the effectiveness of SWGA in producing reliable genomic data from complex clinical samples. Our results provide the identity of genomic loci that may be associated with current antimalarial drug use, including artemisinin and lumefantrine, and reveal selection pressure predicted to compromise the efficacy of current vaccine candidates.
Collapse
Affiliation(s)
- Erin Coonahan
- School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Hunter Gage
- School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Daisy Chen
- Department of Pediatrics, University of California San Diego (UCSD), La Jolla, California, USA
| | - Emilia Virginia Noormahomed
- School of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Microbiology, Parasitology Laboratory, Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique
- Mozambique Institute of Health Education and Research (MIHER), Maputo, Mozambique
| | - Titos Paulo Buene
- Department of Microbiology, Parasitology Laboratory, Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique
- Mozambique Institute of Health Education and Research (MIHER), Maputo, Mozambique
| | - Irina Mendes de Sousa
- Mozambique Institute of Health Education and Research (MIHER), Maputo, Mozambique
- Biological Sciences Department, Faculty of Sciences, Eduardo Mondlane University, Maputo, Mozambique
| | - Kevan Akrami
- School of Medicine, University of California San Diego, La Jolla, California, USA
- Faculdade de Medicina da Bahia, Universidade Federal da Bahia, Salvador, Brazil
| | - Lucia Chambal
- Mozambique Institute of Health Education and Research (MIHER), Maputo, Mozambique
- Department of Internal Medicine, Faculty of Medicine, Eduardo Mondlane University, Maputo, Mozambique
- Maputo Central Hospital, Maputo, Mozambique
| | - Robert T. Schooley
- School of Medicine, University of California San Diego, La Jolla, California, USA
| | - Elizabeth A. Winzeler
- Department of Pediatrics, University of California San Diego (UCSD), La Jolla, California, USA
| | - Annie N. Cowell
- School of Medicine, University of California San Diego, La Jolla, California, USA
| |
Collapse
|
13
|
De Meulenaere K, Cuypers B, Gamboa D, Laukens K, Rosanas-Urgell A. A new Plasmodium vivax reference genome for South American isolates. BMC Genomics 2023; 24:606. [PMID: 37821878 PMCID: PMC10568799 DOI: 10.1186/s12864-023-09707-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 09/30/2023] [Indexed: 10/13/2023] Open
Abstract
BACKGROUND Plasmodium vivax is the second most important cause of human malaria worldwide, and accounts for the majority of malaria cases in South America. A high-quality reference genome exists for Papua Indonesia (PvP01) and Thailand (PvW1), but is lacking for South America. A reference genome specifically for South America would be beneficial though, as P. vivax is a genetically diverse parasite with geographical clustering. RESULTS This study presents a new high-quality assembly of a South American P. vivax isolate, referred to as PvPAM (P. vivax Peruvian AMazon). The genome was obtained from a low input patient sample from the Peruvian Amazon and sequenced using PacBio technology, resulting in a highly complete assembly with 6497 functional genes. Telomeric ends were present in 17 out of 28 chromosomal ends, and additional (sub)telomeric regions are present in 12 unassigned contigs. A comparison of multigene families between PvPAM and the PvP01 genome revealed remarkable variation in vir genes, and the presence of merozoite surface proteins (MSP) 3.6 and 3.7. Three dhfr and dhps drug resistance associated mutations are present in PvPAM, similar to those found in other Peruvian isolates. Mapping of publicly available South American whole genome sequencing (WGS) data to PvPAM resulted in significantly fewer variants and truncated reads compared to the use of PvP01 or PvW1 as reference genomes. To minimize the number of core genome variants in non-South American samples, PvW1 is most suited for Southeast Asian isolates, both PvPAM and PvW1 are suited for South Asian isolates, and PvPAM is recommended for African isolates. Interestingly, non-South American samples still contained the least subtelomeric variants when mapped to PvPAM, indicating high quality of the PvPAM subtelomeric regions. CONCLUSIONS Our findings show that the PvPAM reference genome more accurately represents South American P. vivax isolates in comparison to PvP01 and PvW1. In addition, PvPAM has a high level of completeness, and contains a similar number of annotated genes as PvP01 or PvW1. The PvPAM genome therefore will be a valuable resource to improve future genomic analyses on P. vivax isolates from the South American continent.
Collapse
Affiliation(s)
- Katlijn De Meulenaere
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.
- Department of Computer Science, University of Antwerp, Antwerp, Belgium.
| | - Bart Cuypers
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Dionicia Gamboa
- Instituto de Medicina Tropical Alexander von Humboldt, Universidad Peruana Cayetano Heredia, Lima, Peru
- Departamento de Ciencias Celulares y Moleculares, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Kris Laukens
- Department of Computer Science, University of Antwerp, Antwerp, Belgium
| | - Anna Rosanas-Urgell
- Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp, Antwerp, Belgium.
| |
Collapse
|
14
|
Desai SA. Unique Properties of Nutrient Channels on Plasmodium-Infected Erythrocytes. Pathogens 2023; 12:1211. [PMID: 37887727 PMCID: PMC10610302 DOI: 10.3390/pathogens12101211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 09/26/2023] [Accepted: 09/30/2023] [Indexed: 10/28/2023] Open
Abstract
Intracellular malaria parasites activate an ion and organic solute channel on their host erythrocyte membrane to acquire a broad range of essential nutrients. This plasmodial surface anion channel (PSAC) facilitates the uptake of sugars, amino acids, purines, some vitamins, and organic cations, but remarkably, it must exclude the small Na+ ion to preserve infected erythrocyte osmotic stability in plasma. Although molecular, biochemical, and structural studies have provided fundamental mechanistic insights about PSAC and advanced potent inhibitors as exciting antimalarial leads, important questions remain about how nutrients and ions are transported. Here, I review PSAC's unusual selectivity and conductance properties, which should guide future research into this important microbial ion channel.
Collapse
Affiliation(s)
- Sanjay Arvind Desai
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA
| |
Collapse
|
15
|
Chaux F, Agier N, Garrido C, Fischer G, Eberhard S, Xu Z. Telomerase-independent survival leads to a mosaic of complex subtelomere rearrangements in Chlamydomonas reinhardtii. Genome Res 2023; 33:1582-1598. [PMID: 37580131 PMCID: PMC10620057 DOI: 10.1101/gr.278043.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 08/09/2023] [Indexed: 08/16/2023]
Abstract
Telomeres and subtelomeres, the genomic regions located at chromosome extremities, are essential for genome stability in eukaryotes. In the absence of the canonical maintenance mechanism provided by telomerase, telomere shortening induces genome instability. The landscape of the ensuing genome rearrangements is not accessible by short-read sequencing. Here, we leverage Oxford Nanopore Technologies long-read sequencing to survey the extensive repertoire of genome rearrangements in telomerase mutants of the model green microalga Chlamydomonas reinhardtii In telomerase-mutant strains grown for hundreds of generations, most chromosome extremities were capped by short telomere sequences that were either recruited de novo from other loci or maintained in a telomerase-independent manner. Other extremities did not end with telomeres but only with repeated subtelomeric sequences. The subtelomeric elements, including rDNA, were massively rearranged and involved in breakage-fusion-bridge cycles, translocations, recombinations, and chromosome circularization. These events were established progressively over time and displayed heterogeneity at the subpopulation level. New telomere-capped extremities composed of sequences originating from more internal genomic regions were associated with high DNA methylation, suggesting that de novo heterochromatin formation contributes to the restoration of chromosome end stability in C. reinhardtii The diversity of alternative strategies present in the same organism to maintain chromosome integrity and the variety of rearrangements found in telomerase mutants are remarkable, and illustrate genome plasticity at short timescales.
Collapse
Affiliation(s)
- Frédéric Chaux
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Nicolas Agier
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Clotilde Garrido
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Gilles Fischer
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France;
| |
Collapse
|
16
|
Su X, Stadler RV, Xu F, Wu J. Malaria Genomics, Vaccine Development, and Microbiome. Pathogens 2023; 12:1061. [PMID: 37624021 PMCID: PMC10459703 DOI: 10.3390/pathogens12081061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/14/2023] [Accepted: 08/15/2023] [Indexed: 08/26/2023] Open
Abstract
Recent advances in malaria genetics and genomics have transformed many aspects of malaria research in areas of molecular evolution, epidemiology, transmission, host-parasite interaction, drug resistance, pathogenicity, and vaccine development. Here, in addition to introducing some background information on malaria parasite biology, parasite genetics/genomics, and genotyping methods, we discuss some applications of genetic and genomic approaches in vaccine development and in studying interactions with microbiota. Genetic and genomic data can be used to search for novel vaccine targets, design an effective vaccine strategy, identify protective antigens in a whole-organism vaccine, and evaluate the efficacy of a vaccine. Microbiota has been shown to influence disease outcomes and vaccine efficacy; studying the effects of microbiota in pathogenicity and immunity may provide information for disease control. Malaria genetics and genomics will continue to contribute greatly to many fields of malaria research.
Collapse
Affiliation(s)
- Xinzhuan Su
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852, USA; (R.V.S.); (F.X.); (J.W.)
| | | | | | | |
Collapse
|
17
|
Tiedje KE, Zhan Q, Ruybal-Pésantez S, Tonkin-Hill G, He Q, Tan MH, Argyropoulos DC, Deed SL, Ghansah A, Bangre O, Oduro AR, Koram KA, Pascual M, Day KP. Measuring changes in Plasmodium falciparum census population size in response to sequential malaria control interventions. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.18.23290210. [PMID: 37292908 PMCID: PMC10246142 DOI: 10.1101/2023.05.18.23290210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Here we introduce a new endpoint "census population size" to evaluate the epidemiology and control of Plasmodium falciparum infections, where the parasite, rather than the infected human host, is the unit of measurement. To calculate census population size, we rely on a definition of parasite variation known as multiplicity of infection (M O I v a r ), based on the hyper-diversity of the v a r multigene family. We present a Bayesian approach to estimate M O I v a r from sequencing and counting the number of unique DBLα tags (or DBLα types) of v a r genes, and derive from it census population size by summation of M O I v a r in the human population. We track changes in this parasite population size and structure through sequential malaria interventions by indoor residual spraying (IRS) and seasonal malaria chemoprevention (SMC) from 2012 to 2017 in an area of high-seasonal malaria transmission in northern Ghana. Following IRS, which reduced transmission intensity by > 90% and decreased parasite prevalence by ~40-50%, significant reductions in v a r diversity, M O I v a r , and population size were observed in ~2,000 humans across all ages. These changes, consistent with the loss of diverse parasite genomes, were short lived and 32-months after IRS was discontinued and SMC was introduced, v a r diversity and population size rebounded in all age groups except for the younger children (1-5 years) targeted by SMC. Despite major perturbations from IRS and SMC interventions, the parasite population remained very large and retained the v a r population genetic characteristics of a high-transmission system (high v a r diversity; low v a r repertoire similarity) demonstrating the resilience of P. falciparum to short-term interventions in high-burden countries of sub-Saharan Africa.
Collapse
Affiliation(s)
- Kathryn E. Tiedje
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Qi Zhan
- Committee on Genetics, Genomics and Systems Biology, The University of Chicago; Chicago, Illinois, USA
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
| | - Shazia Ruybal-Pésantez
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Gerry Tonkin-Hill
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
- Bioinformatics Division, Walter and Eliza Hall Institute; Melbourne, Australia
| | - Qixin He
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
| | - Mun Hua Tan
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Dionne C. Argyropoulos
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
| | - Samantha L. Deed
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| | - Anita Ghansah
- Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana; Legon, Ghana
| | - Oscar Bangre
- Navrongo Health Research Centre, Ghana Health Service; Navrongo, Ghana
| | - Abraham R. Oduro
- Navrongo Health Research Centre, Ghana Health Service; Navrongo, Ghana
| | - Kwadwo A. Koram
- Epidemiology Department, Noguchi Memorial Institute for Medical Research, University of Ghana; Legon, Ghana
| | - Mercedes Pascual
- Department of Ecology and Evolution, The University of Chicago; Chicago, Illinois, USA
- Santa Fe Institute, Santa Fe, New Mexico, USA
| | - Karen P. Day
- Department of Microbiology and Immunology, Bio21 Institute and Peter Doherty Institute, The University of Melbourne; Melbourne, Australia
- School of BioSciences, Bio21 Institute, The University of Melbourne; Melbourne, Australia
| |
Collapse
|
18
|
Barcons-Simon A, Carrington M, Siegel TN. Decoding the impact of nuclear organization on antigenic variation in parasites. Nat Microbiol 2023; 8:1408-1418. [PMID: 37524976 DOI: 10.1038/s41564-023-01424-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 06/13/2023] [Indexed: 08/02/2023]
Abstract
Antigenic variation as a strategy to evade the host adaptive immune response has evolved in divergent pathogens. Antigenic variation involves restricted, and often mutually exclusive, expression of dominant antigens and a periodic switch in antigen expression during infection. In eukaryotes, nuclear compartmentalization, including three-dimensional folding of the genome and physical separation of proteins in compartments or condensates, regulates mutually exclusive gene expression and chromosomal translocations. In this Review, we discuss the impact of nuclear organization on antigenic variation in the protozoan pathogens Trypanosoma brucei and Plasmodium falciparum. In particular, we highlight the relevance of nuclear organization in both mutually exclusive antigen expression and genome stability, which underlie antigenic variation.
Collapse
Affiliation(s)
- Anna Barcons-Simon
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
- Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - T Nicolai Siegel
- Division of Experimental Parasitology, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
- Biomedical Center, Division of Physiological Chemistry, Faculty of Medicine, Ludwig-Maximilians-Universität München, Munich, Germany.
| |
Collapse
|
19
|
Ruiz JL, Reimering S, Escobar-Prieto JD, Brancucci NMB, Echeverry DF, Abdi AI, Marti M, Gómez-Díaz E, Otto TD. From contigs towards chromosomes: automatic improvement of long read assemblies (ILRA). Brief Bioinform 2023; 24:bbad248. [PMID: 37406192 PMCID: PMC10359078 DOI: 10.1093/bib/bbad248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/24/2023] [Accepted: 06/16/2023] [Indexed: 07/07/2023] Open
Abstract
Recent advances in long read technologies not only enable large consortia to aim to sequence all eukaryotes on Earth, but they also allow individual laboratories to sequence their species of interest with relatively low investment. Long read technologies embody the promise of overcoming scaffolding problems associated with repeats and low complexity sequences, but the number of contigs often far exceeds the number of chromosomes and they may contain many insertion and deletion errors around homopolymer tracts. To overcome these issues, we have implemented the ILRA pipeline to correct long read-based assemblies. Contigs are first reordered, renamed, merged, circularized, or filtered if erroneous or contaminated. Illumina short reads are used subsequently to correct homopolymer errors. We successfully tested our approach by improving the genome sequences of Homo sapiens, Trypanosoma brucei, and Leptosphaeria spp., and by generating four novel Plasmodium falciparum assemblies from field samples. We found that correcting homopolymer tracts reduced the number of genes incorrectly annotated as pseudogenes, but an iterative approach seems to be required to correct more sequencing errors. In summary, we describe and benchmark the performance of our new tool, which improved the quality of novel long read assemblies up to 1 Gbp. The pipeline is available at GitHub: https://github.com/ThomasDOtto/ILRA.
Collapse
Affiliation(s)
- José Luis Ruiz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, 18016, Granada, Spain
| | - Susanne Reimering
- Department for Computational Biology of Infection Research, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | | | - Nicolas M B Brancucci
- School of Infection & Immunity, MVLS, University of Glasgow, Glasgow, UK
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, 4123 Allschwil, Switzerland
- University of Basel, 4001 Basel, Switzerland
| | - Diego F Echeverry
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
- Departamento de Microbiología, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | | | - Matthias Marti
- School of Infection & Immunity, MVLS, University of Glasgow, Glasgow, UK
| | - Elena Gómez-Díaz
- Instituto de Parasitología y Biomedicina López-Neyra (IPBLN), Consejo Superior de Investigaciones Científicas, 18016, Granada, Spain
| | - Thomas D Otto
- School of Infection & Immunity, MVLS, University of Glasgow, Glasgow, UK
| |
Collapse
|
20
|
Niaré K, Greenhouse B, Bailey JA. An optimized GATK4 pipeline for Plasmodium falciparum whole genome sequencing variant calling and analysis. Malar J 2023; 22:207. [PMID: 37420214 DOI: 10.1186/s12936-023-04632-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/21/2023] [Indexed: 07/09/2023] Open
Abstract
BACKGROUND Accurate variant calls from whole genome sequencing (WGS) of Plasmodium falciparum infections are crucial in malaria population genomics. Here a falciparum variant calling pipeline based on GATK version 4 (GATK4) was optimized and applied to 6626 public Illumina WGS samples. METHODS Control WGS and accurate PacBio assemblies of 10 laboratory strains were leveraged to optimize parameters that control the heterozygosity, local assembly region size, ploidy, mapping and base quality in both GATK HaplotypeCaller and GenotypeGVCFs. From these controls, a high-quality training dataset was generated to recalibrate the raw variant data. RESULTS On current high-quality samples (read length = 250 bp, insert size = 405-524 bp), the optimized pipeline shows improved sensitivity (86.6 ± 1.7% for SNPs and 82.2 ± 5.9% for indels) compared to the default GATK4 pipeline (77.7 ± 1.3% for SNPs; and 73.1 ± 5.1% for indels, adjusted P < 0.001) and previous variant calling with GATK version 3 (GATK3, 70.3 ± 3.0% for SNPs and 59.7 ± 5.8% for indels, adjusted P < 0.001). Its sensitivity on simulated mixed infection samples (80.8 ± 6.1% for SNPs and 78.3 ± 5.1% for indels) was again improved relative to default GATK4 (68.8 ± 6.0% for SNPs and 38.9 ± 0.7% for indels, adjusted, adjusted P < 0.001). Precision was high and comparable across all pipelines on each type of data tested. The resulting combination of high-quality SNPs and indels increases the resolution of local population population structure detection in sub-Saharan Africa. Finally, increasing ploidy improves the detection of drug resistance mutations and estimation of complexity of infection. CONCLUSIONS Overall, this study provides an optimized falciparum GATK4 pipeline resource for variant calling which should help improve genomic studies of malaria.
Collapse
Affiliation(s)
- Karamoko Niaré
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA.
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA.
| | - Bryan Greenhouse
- EPPIcenter Program, Division of HIV, Infectious Diseases, and Global Medicine, Department of Medicine, University of California San Francisco, San Francisco, CA, USA
| | - Jeffrey A Bailey
- Department of Pathology and Laboratory Medicine, Brown University, Providence, RI, USA.
- Center for Computational Molecular Biology, Brown University, Providence, RI, USA.
| |
Collapse
|
21
|
Wiser MF. Knobs, Adhesion, and Severe Falciparum Malaria. Trop Med Infect Dis 2023; 8:353. [PMID: 37505649 PMCID: PMC10385726 DOI: 10.3390/tropicalmed8070353] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/30/2023] [Accepted: 07/02/2023] [Indexed: 07/29/2023] Open
Abstract
Plasmodium falciparum can cause a severe disease with high mortality. A major factor contributing to the increased virulence of P. falciparum, as compared to other human malarial parasites, is the sequestration of infected erythrocytes in the capillary beds of organs and tissues. This sequestration is due to the cytoadherence of infected erythrocytes to endothelial cells. Cytoadherence is primarily mediated by a parasite protein expressed on the surface of the infected erythrocyte called P. falciparum erythrocyte membrane protein-1 (PfEMP1). PfEMP1 is embedded in electron-dense protuberances on the surface of the infected erythrocytes called knobs. These knobs are assembled on the erythrocyte membrane via exported parasite proteins, and the knobs function as focal points for the cytoadherence of infected erythrocytes to endothelial cells. PfEMP1 is a member of the var gene family, and there are approximately 60 antigenically distinct PfEMP1 alleles per parasite genome. Var gene expression exhibits allelic exclusion, with only a single allele being expressed by an individual parasite. This results in sequential waves of antigenically distinct infected erythrocytes and this antigenic variation allows the parasite to establish long-term chronic infections. A wide range of endothelial cell receptors can bind to the various PfEMP1 alleles, and thus, antigenic variation also results in a change in the cytoadherence phenotype. The cytoadherence phenotype may result in infected erythrocytes sequestering in different tissues and this difference in sequestration may explain the wide range of possible clinical manifestations associated with severe falciparum malaria.
Collapse
Affiliation(s)
- Mark F Wiser
- Department of Tropical Medicine and Infectious Disease, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, New Orleans, LA 70112, USA
| |
Collapse
|
22
|
Wichers-Misterek JS, Krumkamp R, Held J, von Thien H, Wittmann I, Höppner YD, Ruge JM, Moser K, Dara A, Strauss J, Esen M, Fendel R, Sulyok Z, Jeninga MD, Kremsner PG, Sim BKL, Hoffman SL, Duffy MF, Otto TD, Gilberger TW, Silva JC, Mordmüller B, Petter M, Bachmann A. The exception that proves the rule: Virulence gene expression at the onset of Plasmodium falciparum blood stage infections. PLoS Pathog 2023; 19:e1011468. [PMID: 37384799 DOI: 10.1371/journal.ppat.1011468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 06/07/2023] [Indexed: 07/01/2023] Open
Abstract
Controlled human malaria infections (CHMI) are a valuable tool to study parasite gene expression in vivo under defined conditions. In previous studies, virulence gene expression was analyzed in samples from volunteers infected with the Plasmodium falciparum (Pf) NF54 isolate, which is of African origin. Here, we provide an in-depth investigation of parasite virulence gene expression in malaria-naïve European volunteers undergoing CHMI with the genetically distinct Pf 7G8 clone, originating in Brazil. Differential expression of var genes, encoding major virulence factors of Pf, PfEMP1s, was assessed in ex vivo parasite samples as well as in parasites from the in vitro cell bank culture that was used to generate the sporozoites (SPZ) for CHMI (Sanaria PfSPZ Challenge (7G8)). We report broad activation of mainly B-type subtelomeric located var genes at the onset of a 7G8 blood stage infection in naïve volunteers, mirroring the NF54 expression study and suggesting that the expression of virulence-associated genes is generally reset during transmission from the mosquito to the human host. However, in 7G8 parasites, we additionally detected a continuously expressed single C-type variant, Pf7G8_040025600, that was most highly expressed in both pre-mosquito cell bank and volunteer samples, suggesting that 7G8, unlike NF54, maintains expression of some previously expressed var variants during transmission. This suggests that in a new host, the parasite may preferentially express the variants that previously allowed successful infection and transmission. Trial registration: ClinicalTrials.gov - NCT02704533; 2018-004523-36.
Collapse
Affiliation(s)
- Jan Stephan Wichers-Misterek
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Ralf Krumkamp
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Jana Held
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Heidrun von Thien
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Irene Wittmann
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Yannick Daniel Höppner
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Julia M Ruge
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| | - Kara Moser
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Antoine Dara
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
| | - Jan Strauss
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Meral Esen
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Cluster of Excellence: EXC 2124: Controlling Microbes to Fight Infection, Tübingen, Germany
| | - Rolf Fendel
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Zita Sulyok
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Myriam D Jeninga
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
| | - Peter G Kremsner
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
- Centre de Recherches Médicales de Lambaréné, Lambaréné, Gabon
| | - B Kim Lee Sim
- Sanaria Inc., Rockville, Maryland, United States of America
| | | | - Michael F Duffy
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Thomas D Otto
- School of Infection & Immunity, University of Glasgow, Glasgow, United Kingdom
| | - Tim-Wolf Gilberger
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Department of Microbiology and Immunology, University of Maryland, School of Medicine, Baltimore, Maryland, United States of America
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade NOVA de Lisboa, UNL, Lisboa, Portugal
| | - Benjamin Mordmüller
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
- German Center for Infection Research (DZIF), partner site Tübingen, Tübingen, Germany
| | - Michaela Petter
- Institute of Microbiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Germany
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, Victoria, Australia
| | - Anna Bachmann
- Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany
- Centre for Structural Systems Biology, Hamburg, Germany, Hamburg, Germany
- Biology Department, University of Hamburg, Hamburg, Germany
- German Center for Infection Research (DZIF), partner site Hamburg-Borstel-Lübeck-Riems, Hamburg/Borstel/Lübeck/Riems, Germany
| |
Collapse
|
23
|
Ruybal-Pesántez S, Sáenz FE, Deed SL, Johnson EK, Larremore DB, Vera-Arias CA, Tiedje KE, Day KP. Molecular epidemiology of continued Plasmodium falciparum disease transmission after an outbreak in Ecuador. FRONTIERS IN TROPICAL DISEASES 2023. [DOI: 10.3389/fitd.2023.1085862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
Abstract
To better understand the factors underlying the continued incidence of clinical episodes of falciparum malaria in E-2025 countries targeting elimination, we characterized the molecular epidemiology of Plasmodium falciparum disease transmission after a clonal outbreak in Ecuador. Here we study disease transmission by documenting the diversity and population structure of the major variant surface antigen of the blood stages of P. falciparum encoded by the var multigene family. We used a high-resolution genotyping method, “varcoding”, involving targeted amplicon sequencing to fingerprint the DBLα encoding region of var genes to describe both antigenic var diversity and var repertoire similarity or relatedness in parasite isolates from clinical cases. We identified nine genetic varcodes in 58 P. falciparum isolates causing clinical disease in 2013-2015. Network analyses revealed that four of the varcodes were highly related to the outbreak varcode, with identification of possible diversification of the outbreak parasites by recombination as seen in three of those varcodes. The majority of clinical cases in Ecuador were associated with parasites with highly related or recombinant varcodes to the outbreak clone and due to local transmission rather than recent importation of parasites from other endemic countries. Sharing of types in Ecuadorian varcodes to those sampled in South American varcodes reflects historical parasite importation of some varcodes, especially from Colombia and Peru. Our findings highlight the translational application of varcoding for outbreak surveillance in epidemic/unstable malaria transmission, such as in E-2025 countries, and point to the need for surveillance of local reservoirs of infection in Ecuador to achieve the malaria elimination goal by 2025.
Collapse
|
24
|
Niaré K, Greenhouse B, Bailey JA. An Optimized GATK4 Pipeline for Plasmodium falciparum Whole Genome Sequencing Variant Calling and Analysis. RESEARCH SQUARE 2023:rs.3.rs-2561857. [PMID: 36824880 PMCID: PMC9949269 DOI: 10.21203/rs.3.rs-2561857/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Background Accurate variant calls from whole genome sequencing (WGS) of Plasmodium falciparum infections are crucial in malaria population genomics. Here we optimized a falciparum variant calling pipeline based on GATK version 4 (GATK4) and applied it to 6,626 public Illumina WGS samples. Methods We optimized parameters that control the heterozygosity, local assembly region size, ploidy, mapping and base quality in both GATK HaplotypeCaller and GenotypeGVCFs leveraging control WGS and accurate PacBio assemblies of 10 laboratory strains. From these controls we generated a high-quality training dataset to recalibrate the raw variant data. Results On current high-quality samples (read length = 250bp, insert size = 405 - 524 bp ), we show improved sensitivity (86.6 ± 1.7% for SNPs and 82.2 ± 5.9% for indels) compared to the default GATK4 pipeline (77.7 ± 1.3% for SNPs; and 73.1 ± 5.1% for indels, adjusted P < 0.001) and previous variant calling with GATK version 3 (GATK3, 70.3 ± 3.0% for SNPs and 59.7 ± 5.8% for indels, adjusted P < 0.001). The sensitivity of our pipeline on simulated mixed infection samples (80.8 ± 6.1% for SNPs and 78.3 ± 5.1% for indels) was again improved relative to default GATK4 (68.8 ± 6.0% for SNPs and 38.9 ± 0.7% for indels, adjusted P < 0.001). Precision was high and comparable across all pipelines on each type of data tested. We further show that using the combination of high-quality SNPs and indels increases the resolution of local population population structure detection in sub-Saharan Africa. We finally demonstrate that increasing ploidy improves the detection of drug resistance mutations and estimation of complexity of infection. Conclusions Overall, we provide an optimized GATK4 pipeline and resource for falciparum variant calling which should help improve genomic studies of malaria.
Collapse
|
25
|
Ebel ER, Kim BY, McDew-White M, Egan ES, Anderson TJC, Petrov DA. Antigenic diversity in malaria parasites is maintained on extrachromosomal DNA. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.02.526885. [PMID: 36778235 PMCID: PMC9915586 DOI: 10.1101/2023.02.02.526885] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Sequence variation among antigenic var genes enables Plasmodium falciparum malaria parasites to evade host immunity. Using long sequence reads from haploid clones from a mutation accumulation experiment, we detect var diversity inconsistent with simple chromosomal inheritance. We discover putatively circular DNA that is strongly enriched for var genes, which exist in multiple alleles per locus separated by recombination and indel events. Extrachromosomal DNA likely contributes to rapid antigenic diversification in P. falciparum.
Collapse
Affiliation(s)
- Emily R Ebel
- Department of Biology, Stanford University, Stanford, CA, USA
- Department of Pediatrics, School of Medicine, Stanford University, Stanford, CA, USA
- Department of Microbiology and Immunology, School of Medicine, Stanford University, Stanford, CA, USA
| | - Bernard Y Kim
- Department of Biology, Stanford University, Stanford, CA, USA
| | - Marina McDew-White
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
- Present address: Host Pathogen Interaction Program, Southwest National Primate Research Center, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Elizabeth S Egan
- Department of Pediatrics, School of Medicine, Stanford University, Stanford, CA, USA
- Department of Microbiology and Immunology, School of Medicine, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Timothy J C Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, TX, USA
| | - Dmitri A Petrov
- Department of Biology, Stanford University, Stanford, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
| |
Collapse
|
26
|
Disulfide bond and crosslinking analyses reveal inter-domain interactions that contribute to the rigidity of placental malaria VAR2CSA structure and formation of CSA binding channel. Int J Biol Macromol 2023; 226:143-158. [PMID: 36470436 DOI: 10.1016/j.ijbiomac.2022.11.258] [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: 08/26/2022] [Revised: 11/15/2022] [Accepted: 11/24/2022] [Indexed: 12/11/2022]
Abstract
VAR2CSA, a multidomain Plasmodium falciparum protein, mediates the adherence of parasite-infected red blood cells to chondroitin 4-sulfate (C4S) in the placenta, contributing to placental malaria. Therefore, detailed understanding of VAR2CSA structure likely help developing strategies to treat placental malaria. The VAR2CSA ectodomain consists of an N-terminal segment (NTS), six Duffy binding-like (DBL) domains, and three interdomains (IDs) present in sequence NTS-DBL1x-ID1-DBL2x-ID2-DBL3x-DBL4ε-ID3-DBL5ε-DBL6ε. Recent electron microscopy studies showed that VAR2CSA is compactly organized into a globular structure containing C4S-binding channel, and that DBL5ε-DBL6ε arm is attached to the NTS-ID3 core structure. However, the structural elements involved in inter-domain interactions that stabilize the VAR2CSA structure remain largely not understood. Here, limited proteolysis and peptide mapping by mass spectrometry showed that VAR2CSA contains several inter-domain disulfide bonds that stabilize its compact structure. Chemical crosslinking-mass spectrometry showed that all IDs interact with DBL4ε; additionally, IDs interact with other DBL domains, demonstrating that IDs are the key structural scaffolds that shape the functional NTS-ID3 core. Ligand binding analysis suggested that NTS considerably restricts the C4S binding. Overall, our study revealed that inter-domain disulfide bonds and interactions between IDs and DBL domains contribute to the stability of VAR2CSA structural architecture and formation of C4S-binding channel.
Collapse
|
27
|
Tan MH, Shim H, Chan YB, Day KP. Unravelling var complexity: Relationship between DBLα types and var genes in Plasmodium falciparum. FRONTIERS IN PARASITOLOGY 2023; 1. [PMID: 36998722 PMCID: PMC10060044 DOI: 10.3389/fpara.2022.1006341] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The enormous diversity and complexity of var genes that diversify rapidly by recombination has led to the exclusion of assembly of these genes from major genome initiatives (e.g., Pf6). A scalable solution in epidemiological surveillance of var genes is to use a small ‘tag’ region encoding the immunogenic DBLα domain as a marker to estimate var diversity. As var genes diversify by recombination, it is not clear the extent to which the same tag can appear in multiple var genes. This relationship between marker and gene has not been investigated in natural populations. Analyses of in vitro recombination within and between var genes have suggested that this relationship would not be exclusive. Using a dataset of publicly-available assembled var sequences, we test this hypothesis by studying DBLα-var relationships for four study sites in four countries: Pursat (Cambodia) and Mae Sot (Thailand), representing low malaria transmission, and Navrongo (Ghana) and Chikwawa (Malawi), representing high malaria transmission. In all study sites, DBLα-var relationships were shown to be predominantly 1-to-1, followed by a second largest proportion of 1-to-2 DBLα-var relationships. This finding indicates that DBLα tags can be used to estimate not just DBLα diversity but var gene diversity when applied in a local endemic area. Epidemiological applications of this result are discussed.
Collapse
Affiliation(s)
- Mun Hua Tan
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute, Melbourne, VIC, Australia
| | - Heejung Shim
- School of Mathematics and Statistics/Melbourne Integrative Genomics, The University of Melbourne, Melbourne, VIC, Australia
| | - Yao-ban Chan
- School of Mathematics and Statistics/Melbourne Integrative Genomics, The University of Melbourne, Melbourne, VIC, Australia
| | - Karen P. Day
- Department of Microbiology and Immunology, The University of Melbourne, Bio21 Institute, Melbourne, VIC, Australia
- CORRESPONDENCE Karen P. Day,
| |
Collapse
|
28
|
Zhang X, Deitsch KW. The mystery of persistent, asymptomatic Plasmodium falciparum infections. Curr Opin Microbiol 2022; 70:102231. [PMID: 36327690 PMCID: PMC10500611 DOI: 10.1016/j.mib.2022.102231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 08/31/2022] [Accepted: 10/12/2022] [Indexed: 01/25/2023]
Abstract
Plasmodium falciparum causes millions of malaria infections and hundreds of thousands of deaths annually. These parasites avoid the adaptive immune response by systematically cycling through a limited repertoire of variant surface antigens after which the number of circulating parasites drops to extremely low levels, coinciding with a loss of symptoms and eventual clearance of the infection. However, in regions with extended dry seasons or in individuals who no longer reside in endemic areas, asymptomatic infections have been observed to persist for many months or years, potentially serving as reservoirs for transmission. Recent work suggests the possibility that parasites can assume a state in which no variant surface antigens are expressed, thus rendering them virtually invisible to the immune system and enabling them to persist at low levels indefinitely.
Collapse
Affiliation(s)
- Xu Zhang
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA.
| |
Collapse
|
29
|
Dunn MJ, Shazib SUA, Simonton E, Slot JC, Anderson MZ. Architectural groups of a subtelomeric gene family evolve along distinct paths in Candida albicans. G3 (BETHESDA, MD.) 2022; 12:jkac283. [PMID: 36269198 PMCID: PMC9713401 DOI: 10.1093/g3journal/jkac283] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 10/09/2022] [Indexed: 12/08/2023]
Abstract
Subtelomeres are dynamic genomic regions shaped by elevated rates of recombination, mutation, and gene birth/death. These processes contribute to formation of lineage-specific gene family expansions that commonly occupy subtelomeres across eukaryotes. Investigating the evolution of subtelomeric gene families is complicated by the presence of repetitive DNA and high sequence similarity among gene family members that prevents accurate assembly from whole genome sequences. Here, we investigated the evolution of the telomere-associated (TLO) gene family in Candida albicans using 189 complete coding sequences retrieved from 23 genetically diverse strains across the species. Tlo genes conformed to the 3 major architectural groups (α/β/γ) previously defined in the genome reference strain but significantly differed in the degree of within-group diversity. One group, Tloβ, was always found at the same chromosome arm with strong sequence similarity among all strains. In contrast, diverse Tloα sequences have proliferated among chromosome arms. Tloγ genes formed 7 primary clades that included each of the previously identified Tloγ genes from the genome reference strain with 3 Tloγ genes always found on the same chromosome arm among strains. Architectural groups displayed regions of high conservation that resolved newly identified functional motifs, providing insight into potential regulatory mechanisms that distinguish groups. Thus, by resolving intraspecies subtelomeric gene variation, it is possible to identify previously unknown gene family complexity that may underpin adaptive functional variation.
Collapse
Affiliation(s)
- Matthew J Dunn
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Shahed U A Shazib
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Emily Simonton
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Jason C Slot
- Department of Plant Pathology, The Ohio State University, Columbus, OH 43210, USA
| | - Matthew Z Anderson
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
- Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH 43210, USA
| |
Collapse
|
30
|
Nair S, Li X, Nkhoma SC, Anderson T. Fitness Costs of pfhrp2 and pfhrp3 Deletions Underlying Diagnostic Evasion in Malaria Parasites. J Infect Dis 2022; 226:1637-1645. [PMID: 35709327 PMCID: PMC10205895 DOI: 10.1093/infdis/jiac240] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 06/14/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Rapid diagnostic tests based on detection of histidine-rich proteins (HRPs) are widely used for malaria diagnosis, but parasites carrying pfhrp deletions can evade detection and are increasing in frequency in some countries. Models aim to predict conditions under which pfhrp2 and/or pfhrp3 deletions will increase, but a key parameter-the fitness cost of deletions-is unknown. METHODS We removed pfhrp2 and/or pfhrp3 from a Malawian parasite clone using gene editing approaches) and measured fitness costs by conducting pairwise competition experiments. RESULTS We observed significant fitness costs of 0.087 ± 0.008 (1 standard error) per asexual cycle for pfhrp2 deletion and 0.113 ± 0.008 for the pfhrp2/3 double deletion, relative to the unedited progenitor parasite. Selection against deletions is strong and comparable to that resulting from drug resistance mutations. CONCLUSIONS Prior modeling suggested that diagnostic selection may drive increased frequency of pfhrp deletions only when fitness costs are mild. Our experiments show that costs of pfhrp deletions are higher than these thresholds, but modeling and empirical results can be reconciled if the duration of infection is short. These results may inform future modeling to understand why pfhrp2/3 deletions are increasing in some locations (Ethiopia and Eritrea) but not in others (Mekong region).
Collapse
Affiliation(s)
- Shalini Nair
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Xue Li
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| | - Standwell C Nkhoma
- BEI Resources, American Type Culture Collection, Manassas, Virginia, USA
| | - Tim Anderson
- Disease Intervention and Prevention Program, Texas Biomedical Research Institute, San Antonio, Texas, USA
| |
Collapse
|
31
|
Brashear AM, Cui L. Population genomics in neglected malaria parasites. Front Microbiol 2022; 13:984394. [PMID: 36160257 PMCID: PMC9493318 DOI: 10.3389/fmicb.2022.984394] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Malaria elimination includes neglected human malaria parasites Plasmodium vivax, Plasmodium ovale spp., and Plasmodium malariae. Biological features such as association with low-density infection and the formation of hypnozoites responsible for relapse make their elimination challenging. Studies on these parasites rely primarily on clinical samples due to the lack of long-term culture techniques. With improved methods to enrich parasite DNA from clinical samples, whole-genome sequencing of the neglected malaria parasites has gained increasing popularity. Population genomics of more than 2200 P. vivax global isolates has improved our knowledge of parasite biology and host-parasite interactions, identified vaccine targets and potential drug resistance markers, and provided a new way to track parasite migration and introduction and monitor the evolutionary response of local populations to elimination efforts. Here, we review advances in population genomics for neglected malaria parasites, discuss how the rich genomic information is being used to understand parasite biology and epidemiology, and explore opportunities for the applications of malaria genomic data in malaria elimination practice.
Collapse
|
32
|
A nuclear redox sensor modulates gene activation and var switching in Plasmodium falciparum. Proc Natl Acad Sci U S A 2022; 119:e2201247119. [PMID: 35939693 PMCID: PMC9388093 DOI: 10.1073/pnas.2201247119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The virulence of Plasmodium falciparum, which causes the deadliest form of human malaria, is attributed to its ability to evade the human immune response. These parasites "choose" to express a single variant from a repertoire of surface antigens called PfEMP1, which are placed on the surface of the infected red cell. Immune evasion is achieved by switches in expression between var genes, each encoding a different PfEMP1 variant. While the mechanisms that regulate mutually exclusive expression of var genes are still elusive, antisense long-noncoding RNAs (lncRNAs) transcribed from the intron of the active var gene were implicated in the "choice" of the single active var gene. Here, we show that this lncRNA colocalizes with the site of var mRNA transcription and is anchored to the var locus via DNA:RNA interactions. We define the var lncRNA interactome and identify a redox sensor, P. falciparum thioredoxin peroxidase I (PfTPx-1), as one of the proteins associated with the var antisense lncRNA. We show that PfTPx-1 localizes to a nuclear subcompartment associated with active transcription on the nuclear periphery, in ring-stage parasite, when var transcription occurs. In addition, PfTPx-1 colocalizes with S-adenosylmethionine synthetase (PfSAMS) in the nucleus, and its overexpression leads to activation of var2csa, similar to overexpression of PfSAMS. Furthermore, we show that PfTPx-1 knockdown alters the var switch rate as well as activation of additional gene subsets. Taken together, our data indicate that nuclear PfTPx-1 plays a role in gene activation possibly by providing a redox-controlled nuclear microenvironment ideal for active transcription.
Collapse
|
33
|
Carpi G, Gorenstein L, Harkins TT, Samadi M, Vats P. A GPU-accelerated compute framework for pathogen genomic variant identification to aid genomic epidemiology of infectious disease: a malaria case study. Brief Bioinform 2022; 23:6658853. [PMID: 35945154 PMCID: PMC9487672 DOI: 10.1093/bib/bbac314] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 06/03/2022] [Accepted: 07/12/2022] [Indexed: 11/15/2022] Open
Abstract
As recently demonstrated by the COVID-19 pandemic, large-scale pathogen genomic data are crucial to characterize transmission patterns of human infectious diseases. Yet, current methods to process raw sequence data into analysis-ready variants remain slow to scale, hampering rapid surveillance efforts and epidemiological investigations for disease control. Here, we introduce an accelerated, scalable, reproducible, and cost-effective framework for pathogen genomic variant identification and present an evaluation of its performance and accuracy across benchmark datasets of Plasmodium falciparum malaria genomes. We demonstrate superior performance of the GPU framework relative to standard pipelines with mean execution time and computational costs reduced by 27× and 4.6×, respectively, while delivering 99.9% accuracy at enhanced reproducibility.
Collapse
Affiliation(s)
- Giovanna Carpi
- Department of Biological Sciences, Purdue University, West Lafayette, IN, USA.,Purdue Institute for Inflammation, Immunology, & Infectious Disease, Purdue University, West Lafayette, IN, USA.,W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Malaria Research Institute, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Lev Gorenstein
- Rosen Center for Advanced Computing, Purdue University, West Lafayette IN, USA
| | | | | | - Pankaj Vats
- NVIDIA, 2788 San Tomas, Santa Clara, CA, USA
| |
Collapse
|
34
|
Beshir KB, Parr JB, Cunningham J, Cheng Q, Rogier E. Screening strategies and laboratory assays to support Plasmodium falciparum histidine-rich protein deletion surveillance: where we are and what is needed. Malar J 2022; 21:201. [PMID: 35751070 PMCID: PMC9233320 DOI: 10.1186/s12936-022-04226-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 06/17/2022] [Indexed: 11/10/2022] Open
Abstract
Rapid diagnostic tests (RDTs) detecting Plasmodium falciparum histidine-rich protein 2 (HRP2) have been an important tool for malaria diagnosis, especially in resource-limited settings lacking quality microscopy. Plasmodium falciparum parasites with deletion of the pfhrp2 gene encoding this antigen have now been identified in dozens of countries across Asia, Africa, and South America, with new reports revealing a high prevalence of deletions in some selected regions. To determine whether HRP2-based RDTs are appropriate for continued use in a locality, focused surveys and/or surveillance activities of the endemic P. falciparum population are needed. Various survey and laboratory methods have been used to determine parasite HRP2 phenotype and pfhrp2 genotype, and the data collected by these different methods need to be interpreted in the appropriate context of survey and assay utilized. Expression of the HRP2 antigen can be evaluated using point-of-care RDTs or laboratory-based immunoassays, but confirmation of a deletion (or mutation) of pfhrp2 requires more intensive laboratory molecular assays, and new tools and strategies for rigorous but practical data collection are particularly needed for large surveys. Because malaria diagnostic strategies are typically developed at the national level, nationally representative surveys and/or surveillance that encompass broad geographical areas and large populations may be required. Here is discussed contemporary assays for the phenotypic and genotypic evaluation of P. falciparum HRP2 status, consider their strengths and weaknesses, and highlight key concepts relevant to timely and resource-conscious workflows required for efficient diagnostic policy decision making.
Collapse
Affiliation(s)
- Khalid B Beshir
- Faculty of Infectious Diseases, London School of Hygiene and Tropical Diseases, Keppel Street, London, WC1E 7HT, UK
| | - Jonathan B Parr
- Division of Infectious Diseases and Institute for Global Health and Infectious Diseases, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Jane Cunningham
- Global Malaria Programme, World Health Organization, Geneva, Switzerland
| | - Qin Cheng
- Drug Resistance and Diagnostics, Australian Defence Force Malaria and Infectious Disease Institute, Brisbane, Australia.,QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Eric Rogier
- Division of Parasitic Diseases and Malaria, Center for Global Health, Centers for Disease Control and Prevention, Atlanta, GA, 30029, USA.
| |
Collapse
|
35
|
Aunin E, Berriman M, Reid AJ. Characterising genome architectures using genome decomposition analysis. BMC Genomics 2022; 23:398. [PMID: 35610562 PMCID: PMC9131526 DOI: 10.1186/s12864-022-08616-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 05/10/2022] [Indexed: 12/14/2022] Open
Abstract
Genome architecture describes how genes and other features are arranged in genomes. These arrangements reflect the evolutionary pressures on genomes and underlie biological processes such as chromosomal segregation and the regulation of gene expression. We present a new tool called Genome Decomposition Analysis (GDA) that characterises genome architectures and acts as an accessible approach for discovering hidden features of a genome assembly. With the imminent deluge of high-quality genome assemblies from projects such as the Darwin Tree of Life and the Earth BioGenome Project, GDA has been designed to facilitate their exploration and the discovery of novel genome biology. We highlight the effectiveness of our approach in characterising the genome architectures of single-celled eukaryotic parasites from the phylum Apicomplexa and show that it scales well to large genomes.
Collapse
Affiliation(s)
- Eerik Aunin
- Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
| | - Matthew Berriman
- Wellcome Sanger Institute, Cambridge, CB10 1SA, UK
- Wellcome Centre for Integrative Parasitology, University of Glasgow, G12 8TA, Glasgow, UK
| | - Adam James Reid
- Wellcome Sanger Institute, Cambridge, CB10 1SA, UK.
- Wellcome/Cancer Research UK Gurdon Institute, University of Cambridge, CB2 1QN, Cambridge, UK.
| |
Collapse
|
36
|
Oresegun DR, Thorpe P, Benavente ED, Campino S, Muh F, Moon RW, Clark TG, Cox-Singh J. De Novo Assembly of Plasmodium knowlesi Genomes From Clinical Samples Explains the Counterintuitive Intrachromosomal Organization of Variant SICAvar and kir Multiple Gene Family Members. Front Genet 2022; 13:855052. [PMID: 35677565 PMCID: PMC9169567 DOI: 10.3389/fgene.2022.855052] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/15/2022] [Indexed: 12/31/2022] Open
Abstract
Plasmodium knowlesi, a malaria parasite of Old World macaque monkeys, is used extensively to model Plasmodium biology. Recently, P. knowlesi was found in the human population of Southeast Asia, particularly Malaysia. P. knowlesi causes uncomplicated to severe and fatal malaria in the human host with features in common with the more prevalent and virulent malaria caused by Plasmodium falciparum. As such, P. knowlesi presents a unique opportunity to develop experimental translational model systems for malaria pathophysiology informed by clinical data from same-species human infections. Experimental lines of P. knowlesi represent well-characterized genetically stable parasites, and to maximize their utility as a backdrop for understanding malaria pathophysiology, genetically diverse contemporary clinical isolates, essentially wild-type, require comparable characterization. The Oxford Nanopore PCR-free long-read sequencing platform was used to sequence and de novo assemble P. knowlesi genomes from frozen clinical samples. The sequencing platform and assembly pipelines were designed to facilitate capturing data and describing, for the first time, P. knowlesi schizont-infected cell agglutination (SICA) var and Knowlesi-Interspersed Repeats (kir) multiple gene families in parasites acquired from nature. The SICAvar gene family members code for antigenically variant proteins analogous to the virulence-associated P. falciparum erythrocyte membrane protein (PfEMP1) multiple var gene family. Evidence presented here suggests that the SICAvar family members have arisen through a process of gene duplication, selection pressure, and variation. Highly evolving genes including PfEMP1family members tend to be restricted to relatively unstable sub-telomeric regions that drive change with core genes protected in genetically stable intrachromosomal locations. The comparable SICAvar and kir gene family members are counter-intuitively located across chromosomes. Here, we demonstrate that, in contrast to conserved core genes, SICAvar and kir genes occupy otherwise gene-sparse chromosomal locations that accommodate rapid evolution and change. The novel methods presented here offer the malaria research community not only new tools to generate comprehensive genome sequence data from small clinical samples but also new insight into the complexity of clinically important real-world parasites.
Collapse
Affiliation(s)
- Damilola R. Oresegun
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Peter Thorpe
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Ernest Diez Benavente
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Susana Campino
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Fauzi Muh
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| | - Robert William Moon
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Taane Gregory Clark
- Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Faculty of Epidemiology and Population Health, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Janet Cox-Singh
- Division of Infection and Global Health, School of Medicine, University of St Andrews, Scotland, United Kingdom
| |
Collapse
|
37
|
Epigenetics of malaria parasite nutrient uptake, but why? Trends Parasitol 2022; 38:618-628. [PMID: 35641406 PMCID: PMC9283302 DOI: 10.1016/j.pt.2022.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 05/01/2022] [Accepted: 05/10/2022] [Indexed: 11/23/2022]
Abstract
The conserved plasmodial surface anion channel (PSAC) mediates nutrient uptake by bloodstream malaria parasites and is an antimalarial target. This pathogen-associated channel is linked to the clag multigene family, which is variably expanded in Plasmodium spp. Member genes are under complex epigenetic regulation, with the clag3 genes of the human P. falciparum pathogen exhibiting monoallelic transcription and mutually exclusive surface exposure on infected erythrocytes. While other multigene families use monoallelic expression to evade host immunity, the reasons of epigenetic control of clag genes are unclear. I consider existing models and their implications for nutrient acquisition and immune evasion. Understanding the reasons for epigenetic regulation of PSAC-mediated nutrient uptake will help clarify host-pathogen interactions and guide development of therapies resistant to allele switching.
Collapse
|
38
|
Florini F, Visone JE, Deitsch KW. Shared Mechanisms for Mutually Exclusive Expression and Antigenic Variation by Protozoan Parasites. Front Cell Dev Biol 2022; 10:852239. [PMID: 35350381 PMCID: PMC8957917 DOI: 10.3389/fcell.2022.852239] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/17/2022] [Indexed: 01/05/2023] Open
Abstract
Cellular decision-making at the level of gene expression is a key process in the development and evolution of every organism. Variations in gene expression can lead to phenotypic diversity and the development of subpopulations with adaptive advantages. A prime example is the mutually exclusive activation of a single gene from within a multicopy gene family. In mammals, this ranges from the activation of one of the two immunoglobulin (Ig) alleles to the choice in olfactory sensory neurons of a single odorant receptor (OR) gene from a family of more than 1,000. Similarly, in parasites like Trypanosoma brucei, Giardia lamblia or Plasmodium falciparum, the process of antigenic variation required to escape recognition by the host immune system involves the monoallelic expression of vsg, vsp or var genes, respectively. Despite the importance of this process, understanding how this choice is made remains an enigma. The development of powerful techniques such as single cell RNA-seq and Hi-C has provided new insights into the mechanisms these different systems employ to achieve monoallelic gene expression. Studies utilizing these techniques have shown how the complex interplay between nuclear architecture, physical interactions between chromosomes and different chromatin states lead to single allele expression. Additionally, in several instances it has been observed that high-level expression of a single gene is preceded by a transient state where multiple genes are expressed at a low level. In this review, we will describe and compare the different strategies that organisms have evolved to choose one gene from within a large family and how parasites employ this strategy to ensure survival within their hosts.
Collapse
|
39
|
Mackenzie G, Jensen RW, Lavstsen T, Otto TD. Varia: a tool for prediction, analysis and visualisation of variable genes. BMC Bioinformatics 2022; 23:52. [PMID: 35073845 PMCID: PMC8785495 DOI: 10.1186/s12859-022-04573-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 01/10/2022] [Indexed: 11/10/2022] Open
Abstract
Background Parasites use polymorphic gene families to evade the immune system or interact with the host. Assessing the diversity and expression of such gene families in pathogens can inform on the repertoire or host interaction phenotypes of clinical relevance. However, obtaining the sequences and quantifying their expression is a challenge. In Plasmodium falciparum, the highly polymorphic var genes encode the major virulence protein, PfEMP1, which bind a range of human receptors through varying combinations of DBL and CIDR domains. Here we present a tool, Varia, to predict near full-length gene sequences and domain compositions of query genes from database genes sharing short sequence tags. Varia generates output through two complementary pipelines. Varia_VIP returns all putative gene sequences and domain compositions of the query gene from any partial sequence provided, thereby enabling experimental validation of specific genes of interest and detailed assessment of their putative domain structure. Varia_GEM accommodates rapid profiling of var gene expression in complex patient samples from DBLα expression sequence tags (EST), by computing a sample overall transcript profile stratified by PfEMP1 domain types. Results Varia_VIP was tested querying sequence tags from all DBL domain types using different search criteria. On average 92% of query tags had one or more 99% identical database hits, resulting in the full-length query gene sequence being identified (> 99% identical DNA > 80% of query gene) among the five most prominent database hits, for ~ 33% of the query genes. Optimized Varia_GEM settings allowed correct prediction of > 90% of domains placed among the four most N-terminal domains, including the DBLα domain, and > 70% of C-terminal domains. With this accuracy, N-terminal domains could be predicted for > 80% of queries, whereas prediction rates of C-terminal domains dropped with the distance from the DBLα from 70 to 40%. Conclusion Prediction of var sequence and domain composition is possible from short sequence tags. Varia can be used to guide experimental validation of PfEMP1 sequences of interest and conduct high-throughput analysis of var type expression in patient samples. Supplementary Information The online version contains supplementary material available at 10.1186/s12859-022-04573-6.
Collapse
|
40
|
Zhou AE, Shah ZV, Bradwell KR, Munro JB, Berry AA, Serre D, Takala-Harrison S, O'Connor TD, Silva JC, Travassos MA. STRIDE: a command-line HMM-based identifier and sub-classifier of Plasmodium falciparum RIFIN and STEVOR variant surface antigen families. BMC Bioinformatics 2022; 23:15. [PMID: 34991452 PMCID: PMC8733436 DOI: 10.1186/s12859-021-04515-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 12/06/2021] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND RIFINs and STEVORs are variant surface antigens expressed by P. falciparum that play roles in severe malaria pathogenesis and immune evasion. These two highly diverse multigene families feature multiple paralogs, making their classification challenging using traditional bioinformatic methods. RESULTS STRIDE (STevor and RIfin iDEntifier) is an HMM-based, command-line program that automates the identification and classification of RIFIN and STEVOR protein sequences in the malaria parasite Plasmodium falciparum. STRIDE is more sensitive in detecting RIFINs and STEVORs than available PFAM and TIGRFAM tools and reports RIFIN subtypes and the number of sequences with a FHEYDER amino acid motif, which has been associated with severe malaria pathogenesis. CONCLUSIONS STRIDE will be beneficial to malaria research groups analyzing genome sequences and transcripts of clinical field isolates, providing insight into parasite biology and virulence.
Collapse
Affiliation(s)
- Albert E Zhou
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Zalak V Shah
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Katie R Bradwell
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - James B Munro
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrea A Berry
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - David Serre
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Shannon Takala-Harrison
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Timothy D O'Connor
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Program in Personalized and Genomic Medicine, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Joana C Silva
- Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Mark A Travassos
- Malaria Research Program, Center for Vaccine Development and Global Health, University of Maryland School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
41
|
Zhang X, Florini F, Visone JE, Lionardi I, Gross MR, Patel V, Deitsch KW. A coordinated transcriptional switching network mediates antigenic variation of human malaria parasites. eLife 2022; 11:83840. [PMID: 36515978 PMCID: PMC9833823 DOI: 10.7554/elife.83840] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 12/13/2022] [Indexed: 12/15/2022] Open
Abstract
Malaria parasites avoid immune clearance through their ability to systematically alter antigens exposed on the surface of infected red blood cells. This is accomplished by tightly regulated transcriptional control of individual members of a large, multicopy gene family called var and is the key to both the virulence and chronic nature of malaria infections. Expression of var genes is mutually exclusive and controlled epigenetically, however how large populations of parasites coordinate var gene switching to avoid premature exposure of the antigenic repertoire is unknown. Here, we provide evidence for a transcriptional network anchored by a universally conserved gene called var2csa that coordinates the switching process. We describe a structured switching bias that shifts overtime and could shape the pattern of var expression over the course of a lengthy infection. Our results provide an explanation for a previously mysterious aspect of malaria infections and shed light on how parasites possessing a relatively small repertoire of variant antigen-encoding genes can coordinate switching events to limit antigen exposure, thereby maintaining chronic infections.
Collapse
Affiliation(s)
- Xu Zhang
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Francesca Florini
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Joseph E Visone
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Irina Lionardi
- Jill Roberts Center for Inflammatory Bowel Disease, Weill Cornell Medical CollegeNew YorkUnited States
| | - Mackensie R Gross
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Valay Patel
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical CollegeNew YorkUnited States
| |
Collapse
|
42
|
Mitesser V, Dzikowski R. Resetting var Gene Transcription in Plasmodium falciparum. Methods Mol Biol 2022; 2470:211-220. [PMID: 35881348 DOI: 10.1007/978-1-0716-2189-9_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
One of the key mechanisms contributing to the virulence of Plasmodium falciparum is its ability to undergo antigenic switching among antigenically distinct variants of the PfEMP1 adhesive proteins, encoded by the var gene family. To avoid premature exposure of its antigenic repertoire, the parasite transcribes its var genes in a mutually exclusive manner, and switch expression at a very slow rate. This process is epigenetically regulated and it relies on "epigenetic memory," which imprints the single active var gene to remain active for multiple replication cycles. Erasing this epigenetic memory in parasites grown in culture resembles parasites, which egress from the liver. It could therefore be of interest for investigating var switching patterns at the onset of malaria infections. In addition, this procedure could be used for creating heterogeneity of var expression among parasite populations. The methodology described here for resetting of var gene expression is based on promoter titration, also known as molecular sponging.
Collapse
Affiliation(s)
- Vera Mitesser
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Ron Dzikowski
- Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Center for the Study of Infectious and Tropical Diseases, Hebrew University-Hadassah Medical School, Jerusalem, Israel.
| |
Collapse
|
43
|
Successful Profiling of Plasmodium falciparum var Gene Expression in Clinical Samples via a Custom Capture Array. mSystems 2021; 6:e0022621. [PMID: 34846163 PMCID: PMC8631312 DOI: 10.1128/msystems.00226-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
var genes encode Plasmodium falciparum erythrocyte membrane protein-1 (PfEMP1) antigens. These highly diverse antigens are displayed on the surface of infected erythrocytes and play a critical role in immune evasion and sequestration of infected erythrocytes. Studies of var expression using non-leukocyte-depleted blood are challenging because of the predominance of host genetic material and lack of conserved var segments. Our goal was to enrich for parasite RNA, allowing de novo assembly of var genes and detection of expressed novel variants. We used two overall approaches: (i) enriching for total mRNA in the sequencing library preparations and (ii) enriching for parasite RNA with a custom capture array based on Roche’s SeqCap EZ enrichment system. The capture array was designed with probes based on the whole 3D7 reference genome and an additional >4,000 full-length var gene sequences from other P. falciparum strains. We tested each method on RNA samples from Malian children with severe or uncomplicated malaria infections. All reads mapping to the human genome were removed, the remaining reads were assembled de novo into transcripts, and from these, var-like transcripts were identified and annotated. The capture array produced the longest maximum length and largest numbers of var gene transcripts in each sample, particularly in samples with low parasitemia. Identifying the most-expressed var gene sequences in whole-blood clinical samples without the need for extensive processing or generating sample-specific reference genome data is critical for understanding the role of PfEMP1s in malaria pathogenesis. IMPORTANCE Malaria parasites display antigens on the surface of infected red blood cells in the human host that facilitate attachment to blood vessels, contributing to the severity of infection. These antigens are highly variable, allowing the parasite to evade the immune system. Identifying these expressed antigens is critical to understanding the development of severe malarial disease. However, clinical samples contain limited amounts of parasite genetic material, a challenge for sequencing efforts further compounded by the extreme diversity of the parasite surface antigens. We present a method that enriches for these antigen sequences in clinical samples using a custom capture array, requiring minimal processing in the field. While our results are focused on the malaria parasite Plasmodium falciparum, this approach has broad applicability to other highly diverse antigens from other parasites and pathogens such as those that cause giardiasis and leishmaniasis.
Collapse
|
44
|
Band G, Leffler EM, Jallow M, Sisay-Joof F, Ndila CM, Macharia AW, Hubbart C, Jeffreys AE, Rowlands K, Nguyen T, Gonçalves S, Ariani CV, Stalker J, Pearson RD, Amato R, Drury E, Sirugo G, d'Alessandro U, Bojang KA, Marsh K, Peshu N, Saelens JW, Diakité M, Taylor SM, Conway DJ, Williams TN, Rockett KA, Kwiatkowski DP. Malaria protection due to sickle haemoglobin depends on parasite genotype. Nature 2021; 602:106-111. [PMID: 34883497 PMCID: PMC8810385 DOI: 10.1038/s41586-021-04288-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 11/29/2021] [Indexed: 11/30/2022]
Abstract
Host genetic factors can confer resistance against malaria1, raising the question of whether this has led to evolutionary adaptation of parasite populations. Here we searched for association between candidate host and parasite genetic variants in 3,346 Gambian and Kenyan children with severe malaria caused by Plasmodium falciparum. We identified a strong association between sickle haemoglobin (HbS) in the host and three regions of the parasite genome, which is not explained by population structure or other covariates, and which is replicated in additional samples. The HbS-associated alleles include nonsynonymous variants in the gene for the acyl-CoA synthetase family member2–4PfACS8 on chromosome 2, in a second region of chromosome 2, and in a region containing structural variation on chromosome 11. The alleles are in strong linkage disequilibrium and have frequencies that covary with the frequency of HbS across populations, in particular being much more common in Africa than other parts of the world. The estimated protective effect of HbS against severe malaria, as determined by comparison of cases with population controls, varies greatly according to the parasite genotype at these three loci. These findings open up a new avenue of enquiry into the biological and epidemiological significance of the HbS-associated polymorphisms in the parasite genome and the evolutionary forces that have led to their high frequency and strong linkage disequilibrium in African P. falciparum populations. A strong association has been found between three regions of the Plasmodium falciparum genome and sickle haemoglobin in children with severe malaria, suggesting parasites have adapted to overcome natural host immunity.
Collapse
Affiliation(s)
- Gavin Band
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
| | - Ellen M Leffler
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Muminatou Jallow
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Edward Francis Small Teaching Hospital (formerly Royal Victoria Teaching Hospital), Independence Drive, Banjul, The Gambia
| | - Fatoumatta Sisay-Joof
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Carolyne M Ndila
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | | | - Christina Hubbart
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Anna E Jeffreys
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Kate Rowlands
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK
| | - Thuy Nguyen
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | | | | | - Jim Stalker
- Wellcome Sanger Institute, Hinxton, Cambridge, UK
| | - Richard D Pearson
- Wellcome Sanger Institute, Hinxton, Cambridge, UK.,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA
| | | | | | - Giorgio Sirugo
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Division of Translational Medicine and Human Genetics, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Umberto d'Alessandro
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kalifa A Bojang
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
| | - Kevin Marsh
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Nuffield Department of Medicine, NDM Research Building, Roosevelt Drive, Headington, Oxford, UK
| | - Norbert Peshu
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya
| | - Joseph W Saelens
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA
| | - Mahamadou Diakité
- Malaria Research and Training Center, University of Sciences, Techniques, and Technologies of Bamako, Bamako, Mali
| | - Steve M Taylor
- Division of Infectious Diseases, Duke University School of Medicine, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - David J Conway
- Medical Research Council Unit The Gambia at the London School of Hygiene and Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia.,Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK
| | - Thomas N Williams
- KEMRI-Wellcome Trust Research Programme, PO Box 230, Kilifi, Kenya.,Institute for Global Health Innovation, Department of Surgery and Cancer, Imperial College, London, London, UK
| | - Kirk A Rockett
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK.
| | - Dominic P Kwiatkowski
- Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford, UK. .,Wellcome Sanger Institute, Hinxton, Cambridge, UK. .,Big Data Institute, Li Ka Shing Centre for Health and Information Discovery, Old Road Campus, Oxford, USA.
| |
Collapse
|
45
|
Characterization of Apicomplexan Amino Acid Transporters (ApiATs) in the Malaria Parasite Plasmodium falciparum. mSphere 2021; 6:e0074321. [PMID: 34756057 PMCID: PMC8579892 DOI: 10.1128/msphere.00743-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During the symptomatic human blood phase, malaria parasites replicate within red blood cells. Parasite proliferation relies on the uptake of nutrients, such as amino acids, from the host cell and blood plasma, requiring transport across multiple membranes. Amino acids are delivered to the parasite through the parasite-surrounding vacuolar compartment by specialized nutrient-permeable channels of the erythrocyte membrane and the parasitophorous vacuole membrane (PVM). However, further transport of amino acids across the parasite plasma membrane (PPM) is currently not well characterized. In this study, we focused on a family of Apicomplexan amino acid transporters (ApiATs) that comprises five members in Plasmodium falciparum. First, we localized four of the P. falciparum ApiATs (PfApiATs) at the PPM using endogenous green fluorescent protein (GFP) tagging. Next, we applied reverse genetic approaches to probe into their essentiality during asexual replication and gametocytogenesis. Upon inducible knockdown and targeted gene disruption, a reduced asexual parasite proliferation was detected for PfApiAT2 and PfApiAT4. Functional inactivation of individual PfApiATs targeted in this study had no effect on gametocyte development. Our data suggest that individual PfApiATs are partially redundant during asexual in vitro proliferation and fully redundant during gametocytogenesis of P. falciparum parasites. IMPORTANCE Malaria parasites live and multiply inside cells. To facilitate their extremely fast intracellular proliferation, they hijack and transform their host cells. This also requires the active uptake of nutrients, such as amino acids, from the host cell and the surrounding environment through various membranes that are the consequence of the parasite’s intracellular lifestyle. In this paper, we focus on a family of putative amino acid transporters termed ApiAT. We show expression and localization of four transporters in the parasite plasma membrane of Plasmodium falciparum-infected erythrocytes that represent one interface of the pathogen to its host cell. We probed into the impact of functional inactivation of individual transporters on parasite growth in asexual and sexual blood stages of P. falciparum and reveal that only two of them show a modest but significant reduction in parasite proliferation but no impact on gametocytogenesis, pointing toward dispensability within this transporter family.
Collapse
|
46
|
Letcher B, Hunt M, Iqbal Z. Gramtools enables multiscale variation analysis with genome graphs. Genome Biol 2021; 22:259. [PMID: 34488837 PMCID: PMC8420074 DOI: 10.1186/s13059-021-02474-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 08/20/2021] [Indexed: 11/24/2022] Open
Abstract
Genome graphs allow very general representations of genetic variation; depending on the model and implementation, variation at different length-scales (single nucleotide polymorphisms (SNPs), structural variants) and on different sequence backgrounds can be incorporated with different levels of transparency. We implement a model which handles this multiscale variation and develop a JSON extension of VCF (jVCF) allowing for variant calls on multiple references, both implemented in our software gramtools. We find gramtools outperforms existing methods for genotyping SNPs overlapping large deletions in M. tuberculosis and is able to genotype on multiple alternate backgrounds in P. falciparum, revealing previously hidden recombination.
Collapse
Affiliation(s)
| | - Martin Hunt
- EMBL-EBI, Hinxton, UK
- Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | | |
Collapse
|
47
|
Faria JRC. A nuclear enterprise: zooming in on nuclear organization and gene expression control in the African trypanosome. Parasitology 2021; 148:1237-1253. [PMID: 33407981 PMCID: PMC8311968 DOI: 10.1017/s0031182020002437] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/22/2020] [Accepted: 12/24/2020] [Indexed: 12/17/2022]
Abstract
African trypanosomes are early divergent protozoan parasites responsible for high mortality and morbidity as well as a great economic burden among the world's poorest populations. Trypanosomes undergo antigenic variation in their mammalian hosts, a highly sophisticated immune evasion mechanism. Their nuclear organization and mechanisms for gene expression control present several conventional features but also a number of striking differences to the mammalian counterparts. Some of these unorthodox characteristics, such as lack of controlled transcription initiation or enhancer sequences, render their monogenic antigen transcription, which is critical for successful antigenic variation, even more enigmatic. Recent technological developments have advanced our understanding of nuclear organization and gene expression control in trypanosomes, opening novel research avenues. This review is focused on Trypanosoma brucei nuclear organization and how it impacts gene expression, with an emphasis on antigen expression. It highlights several dedicated sub-nuclear bodies that compartmentalize specific functions, whilst outlining similarities and differences to more complex eukaryotes. Notably, understanding the mechanisms underpinning antigen as well as general gene expression control is of great importance, as it might help designing effective control strategies against these organisms.
Collapse
Affiliation(s)
- Joana R. C. Faria
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, DundeeDD1 5EH, UK
| |
Collapse
|
48
|
Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021; 49:7571-7587. [PMID: 34165564 PMCID: PMC8287924 DOI: 10.1093/nar/gkab534] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
Collapse
Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| |
Collapse
|
49
|
Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021. [PMID: 34165564 DOI: 10.1101/2021.01.29.428817)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
Collapse
Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| |
Collapse
|
50
|
Gross MR, Hsu R, Deitsch KW. Evolution of transcriptional control of antigenic variation and virulence in human and ape malaria parasites. BMC Ecol Evol 2021; 21:139. [PMID: 34238209 PMCID: PMC8265125 DOI: 10.1186/s12862-021-01872-z] [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] [Received: 04/28/2021] [Accepted: 07/02/2021] [Indexed: 11/13/2022] Open
Abstract
Background The most severe form of human malaria is caused by the protozoan parasite Plasmodium falciparum. This unicellular organism is a member of a subgenus of Plasmodium called the Laverania that infects apes, with P. falciparum being the only member that infects humans. The exceptional virulence of this species to humans can be largely attributed to a family of variant surface antigens placed by the parasites onto the surface of infected red blood cells that mediate adherence to the vascular endothelium. These proteins are encoded by a large, multicopy gene family called var, with each var gene encoding a different form of the protein. By changing which var gene is expressed, parasites avoid immune recognition, a process called antigenic variation that underlies the chronic nature of malaria infections. Results Here we show that the common ancestor of the branch of the Laverania lineage that includes the human parasite underwent a remarkable change in the organization and structure of elements linked to the complex transcriptional regulation displayed by the var gene family. Unlike the other members of the Laverania, the clade that gave rise to P. falciparum evolved distinct subsets of var genes distinguishable by different upstream transcriptional regulatory regions that have been associated with different expression profiles and virulence properties. In addition, two uniquely conserved var genes that have been proposed to play a role in coordinating transcriptional switching similarly arose uniquely within this clade. We hypothesize that these changes originated at a time of dramatic climatic change on the African continent that is predicted to have led to significant changes in transmission dynamics, thus selecting for patterns of antigenic variation that enabled lengthier, more chronic infections. Conclusions These observations suggest that changes in transmission dynamics selected for significant alterations in the transcriptional regulatory mechanisms that mediate antigenic variation in the parasite lineage that includes P. falciparum. These changes likely underlie the chronic nature of these infections as well as their exceptional virulence. Supplementary Information The online version contains supplementary material available at 10.1186/s12862-021-01872-z.
Collapse
Affiliation(s)
- Mackensie R Gross
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Rosie Hsu
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA
| | - Kirk W Deitsch
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, NY, USA.
| |
Collapse
|