1
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Sülzen H, Volkov AN, Geens R, Zahedifard F, Stijlemans B, Zoltner M, Magez S, Sterckx YGJ, Zoll S. Beyond the VSG layer: Exploring the role of intrinsic disorder in the invariant surface glycoproteins of African trypanosomes. PLoS Pathog 2024; 20:e1012186. [PMID: 38648216 PMCID: PMC11065263 DOI: 10.1371/journal.ppat.1012186] [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: 12/18/2023] [Revised: 05/02/2024] [Accepted: 04/10/2024] [Indexed: 04/25/2024] Open
Abstract
In the bloodstream of mammalian hosts, African trypanosomes face the challenge of protecting their invariant surface receptors from immune detection. This crucial role is fulfilled by a dense, glycosylated protein layer composed of variant surface glycoproteins (VSGs), which undergo antigenic variation and provide a physical barrier that shields the underlying invariant surface glycoproteins (ISGs). The protective shield's limited permeability comes at the cost of restricted access to the extracellular host environment, raising questions regarding the specific function of the ISG repertoire. In this study, we employ an integrative structural biology approach to show that intrinsically disordered membrane-proximal regions are a common feature of members of the ISG super-family, conferring the ability to switch between compact and elongated conformers. While the folded, membrane-distal ectodomain is buried within the VSG layer for compact conformers, their elongated counterparts would enable the extension beyond it. This dynamic behavior enables ISGs to maintain a low immunogenic footprint while still allowing them to engage with the host environment when necessary. Our findings add further evidence to a dynamic molecular organization of trypanosome surface antigens wherein intrinsic disorder underpins the characteristics of a highly flexible ISG proteome to circumvent the constraints imposed by the VSG coat.
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Affiliation(s)
- Hagen Sülzen
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
- Faculty of Science, Charles University, Prague, Czech Republic
| | - Alexander N. Volkov
- VIB-VUB Center for Structural Biology, Flemish Institute of Biotechnology (VIB), Brussels, Belgium
- Jean Jeener NMR Centre, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Rob Geens
- VIB-VUB Center for Structural Biology, Flemish Institute of Biotechnology (VIB), Brussels, Belgium
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Center of Excellence, Department of Pharmaceutical Sciences, Universiteit of Antwerp, Wilrijk, Belgium
| | - Farnaz Zahedifard
- Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Benoit Stijlemans
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Myeloid Cell Immunology Laboratory, VIB Center for Inflammation Research, Brussels, Belgium
| | - Martin Zoltner
- Department of Parasitology, Faculty of Science, Charles University in Prague, Biocev, Vestec, Czech Republic
| | - Stefan Magez
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences, Vrije Universiteit Brussel, Brussels, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Gent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Incheon, South Korea
| | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Center of Excellence, Department of Pharmaceutical Sciences, Universiteit of Antwerp, Wilrijk, Belgium
| | - Sebastian Zoll
- Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences, Prague, Czech Republic
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2
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Rogozin IB, Saura A, Poliakov E, Bykova A, Roche-Lima A, Pavlov YI, Yurchenko V. Properties and Mechanisms of Deletions, Insertions, and Substitutions in the Evolutionary History of SARS-CoV-2. Int J Mol Sci 2024; 25:3696. [PMID: 38612505 PMCID: PMC11011937 DOI: 10.3390/ijms25073696] [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: 02/25/2024] [Revised: 03/22/2024] [Accepted: 03/23/2024] [Indexed: 04/14/2024] Open
Abstract
SARS-CoV-2 has accumulated many mutations since its emergence in late 2019. Nucleotide substitutions leading to amino acid replacements constitute the primary material for natural selection. Insertions, deletions, and substitutions appear to be critical for coronavirus's macro- and microevolution. Understanding the molecular mechanisms of mutations in the mutational hotspots (positions, loci with recurrent mutations, and nucleotide context) is important for disentangling roles of mutagenesis and selection. In the SARS-CoV-2 genome, deletions and insertions are frequently associated with repetitive sequences, whereas C>U substitutions are often surrounded by nucleotides resembling the APOBEC mutable motifs. We describe various approaches to mutation spectra analyses, including the context features of RNAs that are likely to be involved in the generation of recurrent mutations. We also discuss the interplay between mutations and natural selection as a complex evolutionary trend. The substantial variability and complexity of pipelines for the reconstruction of mutations and the huge number of genomic sequences are major problems for the analyses of mutations in the SARS-CoV-2 genome. As a solution, we advocate for the development of a centralized database of predicted mutations, which needs to be updated on a regular basis.
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Affiliation(s)
- Igor B. Rogozin
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Andreu Saura
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Eugenia Poliakov
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anastassia Bykova
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Abiel Roche-Lima
- Center for Collaborative Research in Health Disparities—RCMI Program, Medical Sciences Campus, University of Puerto Rico, San Juan 00936, Puerto Rico
| | - Youri I. Pavlov
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
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3
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Kim J, Álvarez-Rodríguez A, Li Z, Radwanska M, Magez S. Recent Progress in the Detection of Surra, a Neglected Disease Caused by Trypanosoma evansi with a One Health Impact in Large Parts of the Tropic and Sub-Tropic World. Microorganisms 2023; 12:44. [PMID: 38257871 PMCID: PMC10819111 DOI: 10.3390/microorganisms12010044] [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: 11/08/2023] [Revised: 12/17/2023] [Accepted: 12/21/2023] [Indexed: 01/24/2024] Open
Abstract
Surra is a wasting disease triggered by infection with Trypanosoma evansi, a protozoan blood parasite that causes mortality and morbidity in a broad spectrum of wild and domestic animals and occasionally humans. Trypanosoma evansi has the widest geographical spread among all pathogenic trypanosomes, inflicting significant worldwide economic problems due to its adverse effects on meat and milk production. For diagnosis, most endemic countries continue to rely on traditional parasitological and serological techniques, such as the analysis of blood smears by microscopy and the Card Agglutination Test for T. evansi (CATT/T. evansi). Although these techniques suffer from a limited positive predictive value (PPV), resource constraints in endemic countries often hinder the adoption of more advanced diagnostic tools such as PCR. This paper addresses diverse diagnostic approaches for identifying T. evansi and assesses their viability in field settings. Moreover, it underscores the urgency of transitioning towards molecular diagnostic techniques such as Loop-Mediated Isothermal Amplification (LAMP) and Recombinase Polymerase Amplification (RPA) for dependable high-PPV point-of-care (POC) diagnostics. Finally, this review delves into strategies to enhance and refine next-generation diagnostics for Surra as part of a One Health approach.
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Affiliation(s)
- Jeongmin Kim
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (J.K.); (A.Á.-R.); (M.R.)
| | - Andrés Álvarez-Rodríguez
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (J.K.); (A.Á.-R.); (M.R.)
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences (DBIT), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Department of Biochemistry and Microbiology WE10, Ghent University, 9000 Ghent, Belgium
| | - Zeng Li
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences (DBIT), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (J.K.); (A.Á.-R.); (M.R.)
- Department of Biomedical Molecular Biology WE14, Ghent University, 9000 Ghent, Belgium
| | - Stefan Magez
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (J.K.); (A.Á.-R.); (M.R.)
- Brussels Center for Immunology (BCIM), Department of Bioengineering Sciences (DBIT), Vrije Universiteit Brussel (VUB), 1050 Brussels, Belgium;
- Department of Biochemistry and Microbiology WE10, Ghent University, 9000 Ghent, Belgium
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4
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Đaković S, Zeelen JP, Gkeka A, Chandra M, van Straaten M, Foti K, Zhong J, Vlachou EP, Aresta-Branco F, Verdi JP, Papavasiliou FN, Stebbins CE. A structural classification of the variant surface glycoproteins of the African trypanosome. PLoS Negl Trop Dis 2023; 17:e0011621. [PMID: 37656766 PMCID: PMC10501684 DOI: 10.1371/journal.pntd.0011621] [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: 04/13/2023] [Revised: 09/14/2023] [Accepted: 08/23/2023] [Indexed: 09/03/2023] Open
Abstract
Long-term immune evasion by the African trypanosome is achieved through repetitive cycles of surface protein replacement with antigenically distinct versions of the dense Variant Surface Glycoprotein (VSG) coat. Thousands of VSG genes and pseudo-genes exist in the parasite genome that, together with genetic recombination mechanisms, allow for essentially unlimited immune escape from the adaptive immune system of the host. The diversity space of the "VSGnome" at the protein level was thought to be limited to a few related folds whose structures were determined more than 30 years ago. However, recent progress has shown that the VSGs possess significantly more architectural variation than had been appreciated. Here we combine experimental X-ray crystallography (presenting structures of N-terminal domains of coat proteins VSG11, VSG21, VSG545, VSG558, and VSG615) with deep-learning prediction using Alphafold to produce models of hundreds of VSG proteins. We classify the VSGnome into groups based on protein architecture and oligomerization state, contextualize recent bioinformatics clustering schemes, and extensively map VSG-diversity space. We demonstrate that in addition to the structural variability and post-translational modifications observed thus far, VSGs are also characterized by variations in oligomerization state and possess inherent flexibility and alternative conformations, lending additional variability to what is exposed to the immune system. Finally, these additional experimental structures and the hundreds of Alphafold predictions confirm that the molecular surfaces of the VSGs remain distinct from variant to variant, supporting the hypothesis that protein surface diversity is central to the process of antigenic variation used by this organism during infection.
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Affiliation(s)
- Sara Đaković
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Johan P. Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Anastasia Gkeka
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monica Chandra
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Konstantina Foti
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Janet Zhong
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Evi P. Vlachou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Francisco Aresta-Branco
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Joseph P. Verdi
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - F. Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - C. Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
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5
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Soni A, Klebanov-Akopyan O, Erben E, Plaschkes I, Benyamini H, Mitesser V, Harel A, Yamin K, Onn I, Shlomai J. UMSBP2 is chromatin remodeler that functions in regulation of gene expression and suppression of antigenic variation in trypanosomes. Nucleic Acids Res 2023; 51:5678-5698. [PMID: 37207337 PMCID: PMC10287944 DOI: 10.1093/nar/gkad402] [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: 12/16/2021] [Accepted: 05/03/2023] [Indexed: 05/21/2023] Open
Abstract
Universal Minicircle Sequence binding proteins (UMSBPs) are CCHC-type zinc-finger proteins that bind the single-stranded G-rich UMS sequence, conserved at the replication origins of minicircles in the kinetoplast DNA, the mitochondrial genome of kinetoplastids. Trypanosoma brucei UMSBP2 has been recently shown to colocalize with telomeres and to play an essential role in chromosome end protection. Here we report that TbUMSBP2 decondenses in vitro DNA molecules, which were condensed by core histones H2B, H4 or linker histone H1. DNA decondensation is mediated via protein-protein interactions between TbUMSBP2 and these histones, independently of its previously described DNA binding activity. Silencing of the TbUMSBP2 gene resulted in a significant decrease in the disassembly of nucleosomes in T. brucei chromatin, a phenotype that could be reverted, by supplementing the knockdown cells with TbUMSBP2. Transcriptome analysis revealed that silencing of TbUMSBP2 affects the expression of multiple genes in T. brucei, with a most significant effect on the upregulation of the subtelomeric variant surface glycoproteins (VSG) genes, which mediate the antigenic variation in African trypanosomes. These observations suggest that UMSBP2 is a chromatin remodeling protein that functions in the regulation of gene expression and plays a role in the control of antigenic variation in T. brucei.
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Affiliation(s)
- Awakash Soni
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel- Canada and the Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Olga Klebanov-Akopyan
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel- Canada and the Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Esteban Erben
- Heidelberg University Center for Molecular Biology at Heidelberg University, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Inbar Plaschkes
- The Info-Core Bioinformatics Unit, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Hadar Benyamini
- The Info-Core Bioinformatics Unit, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Vera Mitesser
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel- Canada and the Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
| | - Amnon Harel
- Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold Street, Safed1311502, Israel
| | - Katereena Yamin
- Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold Street, Safed1311502, Israel
| | - Itay Onn
- Azrieli Faculty of Medicine, Bar-Ilan University, 8 Henrietta Szold Street, Safed1311502, Israel
| | - Joseph Shlomai
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel- Canada and the Kuvin Center for the Study of Infectious and Tropical Diseases, The Hebrew University of Jerusalem, Jerusalem 91120, Israel
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6
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Gkeka A, Aresta-Branco F, Triller G, Vlachou EP, van Straaten M, Lilic M, Olinares PDB, Perez K, Chait BT, Blatnik R, Ruppert T, Verdi JP, Stebbins CE, Papavasiliou FN. Immunodominant surface epitopes power immune evasion in the African trypanosome. Cell Rep 2023; 42:112262. [PMID: 36943866 DOI: 10.1016/j.celrep.2023.112262] [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: 06/09/2022] [Revised: 12/02/2022] [Accepted: 02/28/2023] [Indexed: 03/23/2023] Open
Abstract
The African trypanosome survives the immune response of its mammalian host by antigenic variation of its major surface antigen (the variant surface glycoprotein or VSG). Here we describe the antibody repertoires elicited by different VSGs. We show that the repertoires are highly restricted and are directed predominantly to distinct epitopes on the surface of the VSGs. They are also highly discriminatory; minor alterations within these exposed epitopes confer antigenically distinct properties to these VSGs and elicit different repertoires. We propose that the patterned and repetitive nature of the VSG coat focuses host immunity to a restricted set of immunodominant epitopes per VSG, eliciting a highly stereotyped response, minimizing cross-reactivity between different VSGs and facilitating prolonged immune evasion through epitope variation.
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Affiliation(s)
- Anastasia Gkeka
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany; Faculty of Biosciences, University of Heidelberg, 69120 Heidelberg, Germany; Panosome GmbH, 69123 Heidelberg, Germany
| | - Francisco Aresta-Branco
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany; Division of Structural Biology of Infection and Immunity, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Gianna Triller
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Evi P Vlachou
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, 69120 Heidelberg, Germany
| | - Mirjana Lilic
- Laboratory of Structural Microbiology, the Rockefeller University, New York, NY 10065, USA
| | - Paul Dominic B Olinares
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, the Rockefeller University, New York, NY 10065, USA
| | - Kathryn Perez
- Protein Expression and Purification Core Facility, EMBL Heidelberg, 69117 Heidelberg, Germany
| | - Brian T Chait
- Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, the Rockefeller University, New York, NY 10065, USA
| | - Renata Blatnik
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Thomas Ruppert
- Center for Molecular Biology of Heidelberg University, DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Joseph P Verdi
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany; Panosome GmbH, 69123 Heidelberg, Germany
| | - C Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, 69120 Heidelberg, Germany.
| | - F Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, 69120 Heidelberg, Germany.
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7
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Casas-Sanchez A, Ramaswamy R, Perally S, Haines LR, Rose C, Aguilera-Flores M, Portillo S, Verbeelen M, Hussain S, Smithson L, Yunta C, Lehane MJ, Vaughan S, van den Abbeele J, Almeida IC, Boulanger MJ, Acosta-Serrano Á. The Trypanosoma brucei MISP family of invariant proteins is co-expressed with BARP as triple helical bundle structures on the surface of salivary gland forms, but is dispensable for parasite development within the tsetse vector. PLoS Pathog 2023; 19:e1011269. [PMID: 36996244 PMCID: PMC10089363 DOI: 10.1371/journal.ppat.1011269] [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: 09/30/2022] [Revised: 04/11/2023] [Accepted: 03/08/2023] [Indexed: 04/01/2023] Open
Abstract
Trypanosoma brucei spp. develop into mammalian-infectious metacyclic trypomastigotes inside tsetse salivary glands. Besides acquiring a variant surface glycoprotein (VSG) coat, little is known about the metacyclic expression of invariant surface antigens. Proteomic analyses of saliva from T. brucei-infected tsetse flies identified, in addition to VSG and Brucei Alanine-Rich Protein (BARP) peptides, a family of glycosylphosphatidylinositol (GPI)-anchored surface proteins herein named as Metacyclic Invariant Surface Proteins (MISP) because of its predominant expression on the surface of metacyclic trypomastigotes. The MISP family is encoded by five paralog genes with >80% protein identity, which are exclusively expressed by salivary gland stages of the parasite and peak in metacyclic stage, as shown by confocal microscopy and immuno-high resolution scanning electron microscopy. Crystallographic analysis of a MISP isoform (MISP360) and a high confidence model of BARP revealed a triple helical bundle architecture commonly found in other trypanosome surface proteins. Molecular modelling combined with live fluorescent microscopy suggests that MISP N-termini are potentially extended above the metacyclic VSG coat, and thus could be tested as a transmission-blocking vaccine target. However, vaccination with recombinant MISP360 isoform did not protect mice against a T. brucei infectious tsetse bite. Lastly, both CRISPR-Cas9-driven knock out and RNAi knock down of all MISP paralogues suggest they are not essential for parasite development in the tsetse vector. We suggest MISP may be relevant during trypanosome transmission or establishment in the vertebrate's skin.
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Affiliation(s)
- Aitor Casas-Sanchez
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | | | - Samïrah Perally
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Lee R. Haines
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Clair Rose
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Marcela Aguilera-Flores
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Susana Portillo
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | | | | | - Laura Smithson
- Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | - Cristina Yunta
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Michael J. Lehane
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Sue Vaughan
- Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
| | | | - Igor C. Almeida
- Border Biomedical Research Center, Department of Biological Sciences, University of Texas at El Paso, El Paso, Texas, United States of America
| | - Martin J. Boulanger
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, Canada
| | - Álvaro Acosta-Serrano
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
- Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
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8
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Chandra M, Đaković S, Foti K, Zeelen JP, van Straaten M, Aresta-Branco F, Tihon E, Lübbehusen N, Ruppert T, Glover L, Papavasiliou FN, Stebbins CE. Structural similarities between the metacyclic and bloodstream form variant surface glycoproteins of the African trypanosome. PLoS Negl Trop Dis 2023; 17:e0011093. [PMID: 36780870 PMCID: PMC9956791 DOI: 10.1371/journal.pntd.0011093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/24/2023] [Accepted: 01/12/2023] [Indexed: 02/15/2023] Open
Abstract
During infection of mammalian hosts, African trypanosomes thwart immunity using antigenic variation of the dense Variant Surface Glycoprotein (VSG) coat, accessing a large repertoire of several thousand genes and pseudogenes, and switching to antigenically distinct copies. The parasite is transferred to mammalian hosts by the tsetse fly. In the salivary glands of the fly, the pathogen adopts the metacyclic form and expresses a limited repertoire of VSG genes specific to that developmental stage. It has remained unknown whether the metacyclic VSGs possess distinct properties associated with this particular and discrete phase of the parasite life cycle. We present here three novel metacyclic form VSG N-terminal domain crystal structures (mVSG397, mVSG531, and mVSG1954) and show that they mirror closely in architecture, oligomerization, and surface diversity the known classes of bloodstream form VSGs. These data suggest that the mVSGs are unlikely to be a specialized subclass of VSG proteins, and thus could be poor candidates as the major components of prophylactic vaccines against trypanosomiasis.
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Affiliation(s)
- Monica Chandra
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Sara Đaković
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Konstantina Foti
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Johan P. Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Francisco Aresta-Branco
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Eliane Tihon
- Institut Pasteur, Université Paris Cité, Trypanosome Molecular Biology, Department of Parasites and Insect Vectors, Paris, France
| | - Nicole Lübbehusen
- Centre for Molecular Biology at the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Thomas Ruppert
- Centre for Molecular Biology at the University of Heidelberg (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Lucy Glover
- Institut Pasteur, Université Paris Cité, Trypanosome Molecular Biology, Department of Parasites and Insect Vectors, Paris, France
| | - F. Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - C. Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
- * E-mail:
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9
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Nguyen HTT, Radwanska M, Magez S. Tipping the balance between erythroid cell differentiation and induction of anemia in response to the inflammatory pathology associated with chronic trypanosome infections. Front Immunol 2022; 13:1051647. [PMID: 36420267 PMCID: PMC9676970 DOI: 10.3389/fimmu.2022.1051647] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/19/2022] [Indexed: 11/09/2022] Open
Abstract
Infection caused by extracellular single-celled trypanosomes triggers a lethal chronic wasting disease in livestock and game animals. Through screening of 10 Trypanosoma evansi field isolates, exhibiting different levels of virulence in mice, the current study identifies an experimental disease model in which infection can last well over 100 days, mimicking the major features of chronic animal trypanosomosis. In this model, despite the well-controlled parasitemia, infection is hallmarked by severe trypanosomosis-associated pathology. An in-depth scRNA-seq analysis of the latter revealed the complexity of the spleen macrophage activation status, highlighting the crucial role of tissue resident macrophages (TRMs) in regulating splenic extramedullary erythropoiesis. These new data show that in the field of experimental trypanosomosis, macrophage activation profiles have so far been oversimplified into a bi-polar paradigm (M1 vs M2). Interestingly, TRMs exert a double-sided effect on erythroid cells. On one hand, these cells express an erythrophagocytosis associated signature. On another hand, TRMs show high levels of Vcam1 expression, known to support their interaction with hematopoietic stem and progenitor cells (HSPCs). During chronic infection, the latter exhibit upregulated expression of Klf1, E2f8, and Gfi1b genes, involved in erythroid differentiation and extramedullary erythropoiesis. This process gives rise to differentiation of stem cells to BFU-e/CFU-e, Pro E, and Baso E subpopulations. However, infection truncates progressing differentiation at the orthochromatic erythrocytes level, as demonstrated by scRNAseq and flow cytometry. As such, these cells are unable to pass to the reticulocyte stage, resulting in reduced number of mature circulating RBCs and the occurrence of chronic anemia. The physiological consequence of these events is the prolonged poor delivery of oxygen to various tissues, triggering lactic acid acidosis and the catabolic breakdown of muscle tissue, reminiscent of the wasting syndrome that is characteristic for the lethal stage of animal trypanosomosis.
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Affiliation(s)
- Hang Thi Thu Nguyen
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Stefan Magez
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
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10
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Danazumi AU, Iliyasu Gital S, Idris S, BS Dibba L, Balogun EO, Górna MW. Immunoinformatic design of a putative multi-epitope vaccine candidate against Trypanosoma brucei gambiense. Comput Struct Biotechnol J 2022; 20:5574-5585. [PMID: 36284708 PMCID: PMC9576565 DOI: 10.1016/j.csbj.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 09/13/2022] [Accepted: 10/02/2022] [Indexed: 11/28/2022] Open
Abstract
Human African trypanosomiasis (HAT) is a neglected tropical disease that is caused by flagellated parasites of the genus Trypanosoma. HAT imposes a significant socio-economic burden on many countries in sub-Saharan Africa and its control is hampered by several drawbacks ranging from the ineffectiveness of drugs, complex dosing regimens, drug resistance, and lack of a vaccine. Despite more than a century of research and investigations, the development of a vaccine to tackle HAT is still challenging due to the complex biology of the pathogens. Advancements in computational modeling coupled with the availability of an unprecedented amount of omics data from different organisms have allowed the design of new generation vaccines that offer better antigenicity and safety profile. One of such new generation approaches is a multi-epitope vaccine (MEV) designed from a collection of antigenic peptides. A MEV can stimulate both cellular and humoral immune responses as well as avoiding possible allergenic reactions. Herein, we take advantage of this approach to design a MEV from conserved hypothetical plasma membrane proteins of Trypanosoma brucei gambiense, the trypanosome subspecies that is responsible for the west and central African forms of HAT. The designed MEV is 402 amino acids long (41.5 kDa). It is predicted to be antigenic, non-toxic, to assume a stable 3D conformation, and to interact with a key immune receptor. In addition, immune simulation foresaw adequate immune stimulation by the putative antigen and a lasting memory. Therefore, the designed chimeric vaccine represents a potential candidate that could be used to target HAT.
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Affiliation(s)
- Ammar Usman Danazumi
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Warsaw, Poland,Faculty of Chemistry, Warsaw University of Technology, Warsaw, Poland,Groningen Research Institute of Pharmacy, University of Groningen, the Netherlands,Corresponding authors at: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Warsaw, Poland (A.U. Danazumi, M. W. Górna).
| | | | - Salisu Idris
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria,Department of Medical Laboratory Science, Kazaure School of Health Technology, Jigawa, Nigeria
| | - Lamin BS Dibba
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria,Department of Physical and Natural Sciences, School of Arts and Sciences, University of the Gambia, Brikama Campus. P.O Box 3530, Serrekunda, the Gambia
| | - Emmanuel Oluwadare Balogun
- Department of Biochemistry, Ahmadu Bello University, Zaria, Nigeria,Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria,Center for Discovery and Innovation in Parasitic Diseases, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA,Department of Biomedical Chemistry, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Maria Wiktoria Górna
- Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Warsaw, Poland,Corresponding authors at: Biological and Chemical Research Centre, Department of Chemistry, University of Warsaw, Warsaw, Poland (A.U. Danazumi, M. W. Górna).
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11
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Sharma A, Cipriano M, Ferrins L, Hajduk SL, Mensa-Wilmot K. Hypothesis-generating proteome perturbation to identify NEU-4438 and acoziborole modes of action in the African Trypanosome. iScience 2022; 25:105302. [PMID: 36304107 PMCID: PMC9593816 DOI: 10.1016/j.isci.2022.105302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/24/2022] [Accepted: 09/29/2022] [Indexed: 11/29/2022] Open
Abstract
NEU-4438 is a lead for the development of drugs against Trypanosoma brucei, which causes human African trypanosomiasis. Optimized with phenotypic screening, targets of NEU-4438 are unknown. Herein, we present a cell perturbome workflow that compares NEU-4438's molecular modes of action to those of SCYX-7158 (acoziborole). Following a 6 h perturbation of trypanosomes, NEU-4438 and acoziborole reduced steady-state amounts of 68 and 92 unique proteins, respectively. After analysis of proteomes, hypotheses formulated for modes of action were tested: Acoziborole and NEU-4438 have different modes of action. Whereas NEU-4438 prevented DNA biosynthesis and basal body maturation, acoziborole destabilized CPSF3 and other proteins, inhibited polypeptide translation, and reduced endocytosis of haptoglobin-hemoglobin. These data point to CPSF3-independent modes of action for acoziborole. In case of polypharmacology, the cell-perturbome workflow elucidates modes of action because it is target-agnostic. Finally, the workflow can be used in any cell that is amenable to proteomic and molecular biology experiments.
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Affiliation(s)
- Amrita Sharma
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA
| | - Michael Cipriano
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Lori Ferrins
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA 02115, USA
| | - Stephen L. Hajduk
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Kojo Mensa-Wilmot
- Department of Molecular and Cellular Biology, Kennesaw State University, Kennesaw, GA 30144, USA,Corresponding author
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12
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Abstract
A hallmark of eukaryotic cells is the ability to form a secretory pathway connecting many intracellular compartments. In the early secretory pathway, coated protein complex II (COPII)-coated vesicles mediate the anterograde transport of newly synthesized secretory cargo from the endoplasmic reticulum to the Golgi apparatus. The COPII coat complex is comprised of an inner layer of Sec23/Sec24 heterodimers and an outer layer of Sec13/Sec31 heterotetramers. In African trypanosomes, there are two paralogues each of Sec23 and Sec24, that form obligate heterodimers (TbSec23.2/TbSec24.1, TbSec23.1/TbSec24.2). It is not known if these form distinct homotypic classes of vesicles or one heterotypic class, but it is known that TbSec23.2/TbSec24.1 specifically mediate forward trafficking of GPI-anchored proteins (GPI-APs) in bloodstream-form trypanosomes (BSF). Here, we showed that this selectivity was lost in insect procyclic stage parasites (PCF). All isoforms of TbSec23 and TbSec24 are essential in PCF parasites as judged by RNAi knockdowns. RNAi silencing of each subunit had equivalent effects on the trafficking of GPI-APs and p67, a transmembrane lysosomal protein. However, silencing of the TbSec23.2/TbSec24.1 had heterodimer had a significant impact on COPII mediated trafficking of soluble TbCatL from the ER to the lysosome. This finding suggests a model in which selectivity of COPII transport was altered between the BSF and PCF trypanosomes, possibly as an adaptation to a digenetic life cycle. IMPORTANCE African trypanosomes synthesize dense surface coats composed of stage-specific glycosylphosphatidylinositol lipid anchored proteins. We previously defined specific machinery in bloodstream stage parasites that mediate the exit of these proteins from the endoplasmic reticulum. Here, we performed similar analyses in the procyclic insect stage and found significant differences in this process. These findings contribute to our understanding of secretory processes in this unusual eukaryotic model system.
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13
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Turnover of Variant Surface Glycoprotein in Trypanosoma brucei Is Not Altered in Response to Specific Silencing. mSphere 2022; 7:e0012222. [PMID: 35727016 PMCID: PMC9429888 DOI: 10.1128/msphere.00122-22] [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: 11/20/2022] Open
Abstract
African trypanosomes evade the immune system of the mammalian host by the antigenic variation of the predominant glycosylphosphatidylinositol (GPI)-anchored surface protein, variant surface glycoprotein (VSG). VSG is a very stable protein that is turned over from the cell surface with a long half-life (~26 h), allowing newly synthesized VSG to populate the surface. We have recently demonstrated that VSG turnover under normal growth is mediated by a combination of GPI hydrolysis and direct shedding with intact GPI anchors. VSG synthesis is tightly regulated in dividing trypanosomes, and when subjected to RNA interference (RNAi) silencing, cells display rapid cell cycle arrest in order to conserve VSG density on the cell surface (K. Sheader, S. Vaughan, J. Minchin, K. Hughes, et al., Proc Natl Acad Sci U S A 102:8716-8721, 2005, https://doi.org/10.1073/pnas.0501886102). Arrested cells also display an altered morphology of secretory organelles-engorgement of the trans-Golgi cisternae-that may reflect a disruption of post-Golgi secretory transport. We now ask whether trypanosomes under VSG silencing also reduce the rate of VSG turnover to further conserve coat density. Our data indicate that trypanosomes do not regulate VSG turnover according to VSG protein abundance, nor was there any effect on the post-Golgi transport of soluble or GPI-anchored secretory cargo. However, the surface morphology of silenced cells was altered from a typically rugose topology to a smoother profile, consistent with reduced overall membrane trafficking to the cell surface. IMPORTANCE African trypanosomes evade the host immune system by altering the expression of variant surface glycoproteins (VSGs) in a process called antigenic variation. VSG is essential, and when its synthesis is ablated by RNAi silencing, cells enter precytokinesis growth arrest as a means to maintain constant cell surface VSG levels. We have investigated whether arrested cells also alter the rate of natural VSG turnover as a means to conserve the surface coat. This work provides insights into the natural biology of the glycocalyx of this important human and veterinary parasite.
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14
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Nguyen HTT, Guevarra RB, Magez S, Radwanska M. Single-cell transcriptome profiling and the use of AID deficient mice reveal that B cell activation combined with antibody class switch recombination and somatic hypermutation do not benefit the control of experimental trypanosomosis. PLoS Pathog 2021; 17:e1010026. [PMID: 34762705 PMCID: PMC8610246 DOI: 10.1371/journal.ppat.1010026] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 11/23/2021] [Accepted: 10/11/2021] [Indexed: 01/02/2023] Open
Abstract
Salivarian trypanosomes are extracellular protozoan parasites causing infections in a wide range of mammalian hosts, with Trypanosoma evansi having the widest geographic distribution, reaching territories far outside Africa and occasionally even Europe. Besides causing the animal diseases, T. evansi can cause atypical Human Trypanosomosis. The success of this parasite is attributed to its capacity to evade and disable the mammalian defense response. To unravel the latter, we applied here for the first time a scRNA-seq analysis on splenocytes from trypanosome infected mice, at two time points during infection, i.e. just after control of the first parasitemia peak (day 14) and a late chronic time point during infection (day 42). This analysis was combined with flow cytometry and ELISA, revealing that T. evansi induces prompt activation of splenic IgM+CD1d+ Marginal Zone and IgMIntIgD+ Follicular B cells, coinciding with an increase in plasma IgG2c Ab levels. Despite the absence of follicles, a rapid accumulation of Aicda+ GC-like B cells followed first parasitemia peak clearance, accompanied by the occurrence of Xbp1+ expressing CD138+ plasma B cells and Tbx21+ atypical CD11c+ memory B cells. Ablation of immature CD93+ bone marrow and Vpreb3+Ly6d+Ighm+ expressing transitional spleen B cells prevented mature peripheral B cell replenishment. Interestingly, AID-/- mice that lack the capacity to mount anti-parasite IgG responses, exhibited a superior defense level against T. evansi infections. Here, elevated natural IgMs were able to exert in vivo and in vitro trypanocidal activity. Hence, we conclude that in immune competent mice, trypanosomosis associated B cell activation and switched IgG production is rapidly induced by T. evansi, facilitating an escape from the detrimental natural IgM killing activity, and resulting in increased host susceptibility. This unique role of IgM and its anti-trypanosome activity are discussed in the context of the dilemma this causes for the future development of anti-trypanosome vaccines. Trypanosoma evansi parasites can infect mammals, occasionally also humans, by evading the humoral immune response. In this study, cellular and transcriptomic profiling reveals that T. evansi induces rapid activation of mature splenic B cells, followed by differentiation into Aicda+ GC-like B cells, Tbx21+ atypical memory B cells and Sdc1+Xbp1+ plasma B cells. The process triggers early-stage Ighg2c expression in Follicular B cells. Simultaneous ablation of the bone marrow early B cell lineage prevents B cell replenishment, causing loss of the host’s parasitemia control capacity. Surprisingly, AID-/- mice lacking anti-parasite IgGs, exhibit a superior defense level against T. evansi infections, with elevated natural IgMs being able to exert trypanocidal activity. Hence, we conclude that in immune competent mice, trypanosomosis associated B cell Aicda activation and IgG2c production is rapidly induced by T. evansi in order to evade natural IgM mediated killing, resulting in increased host susceptibility.
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Affiliation(s)
- Hang Thi Thu Nguyen
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | - Robin B. Guevarra
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
| | - Stefan Magez
- Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
- * E-mail: (SM); (MR)
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
- * E-mail: (SM); (MR)
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15
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Hempelmann A, Hartleb L, van Straaten M, Hashemi H, Zeelen JP, Bongers K, Papavasiliou FN, Engstler M, Stebbins CE, Jones NG. Nanobody-mediated macromolecular crowding induces membrane fission and remodeling in the African trypanosome. Cell Rep 2021; 37:109923. [PMID: 34731611 DOI: 10.1016/j.celrep.2021.109923] [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: 03/15/2021] [Revised: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 10/19/2022] Open
Abstract
The dense variant surface glycoprotein (VSG) coat of African trypanosomes represents the primary host-pathogen interface. Antigenic variation prevents clearing of the pathogen by employing a large repertoire of antigenically distinct VSG genes, thus neutralizing the host's antibody response. To explore the epitope space of VSGs, we generate anti-VSG nanobodies and combine high-resolution structural analysis of VSG-nanobody complexes with binding assays on living cells, revealing that these camelid antibodies bind deeply inside the coat. One nanobody causes rapid loss of cellular motility, possibly due to blockage of VSG mobility on the coat, whose rapid endocytosis and exocytosis are mechanistically linked to Trypanosoma brucei propulsion and whose density is required for survival. Electron microscopy studies demonstrate that this loss of motility is accompanied by rapid formation and shedding of nanovesicles and nanotubes, suggesting that increased protein crowding on the dense membrane can be a driving force for membrane fission in living cells.
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Affiliation(s)
- Alexander Hempelmann
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg 69120, Germany
| | - Laura Hartleb
- Department of Cell and Developmental Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität of Würzburg, Würzburg 97074, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg 69120, Germany
| | - Hamidreza Hashemi
- Division of Immune Diversity, German Cancer Research Center, Heidelberg 69120, Germany
| | - Johan P Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg 69120, Germany
| | - Kevin Bongers
- Department of Cell and Developmental Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität of Würzburg, Würzburg 97074, Germany
| | - F Nina Papavasiliou
- Division of Immune Diversity, German Cancer Research Center, Heidelberg 69120, Germany
| | - Markus Engstler
- Department of Cell and Developmental Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität of Würzburg, Würzburg 97074, Germany
| | - C Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg 69120, Germany.
| | - Nicola G Jones
- Department of Cell and Developmental Biology, Theodor-Boveri-Institute, Biocenter, Julius-Maximilians-Universität of Würzburg, Würzburg 97074, Germany.
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16
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Magez S, Li Z, Nguyen HTT, Pinto Torres JE, Van Wielendaele P, Radwanska M, Began J, Zoll S, Sterckx YGJ. The History of Anti-Trypanosome Vaccine Development Shows That Highly Immunogenic and Exposed Pathogen-Derived Antigens Are Not Necessarily Good Target Candidates: Enolase and ISG75 as Examples. Pathogens 2021; 10:pathogens10081050. [PMID: 34451514 PMCID: PMC8400590 DOI: 10.3390/pathogens10081050] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 12/02/2022] Open
Abstract
Salivarian trypanosomes comprise a group of extracellular anthroponotic and zoonotic parasites. The only sustainable method for global control of these infection is through vaccination of livestock animals. Despite multiple reports describing promising laboratory results, no single field-applicable solution has been successful so far. Conventionally, vaccine research focusses mostly on exposed immunogenic antigens, or the structural molecular knowledge of surface exposed invariant immunogens. Unfortunately, extracellular parasites (or parasites with extracellular life stages) have devised efficient defense systems against host antibody attacks, so they can deal with the mammalian humoral immune response. In the case of trypanosomes, it appears that these mechanisms have been perfected, leading to vaccine failure in natural hosts. Here, we provide two examples of potential vaccine candidates that, despite being immunogenic and accessible to the immune system, failed to induce a functionally protective memory response. First, trypanosomal enolase was tested as a vaccine candidate, as it was recently characterized as a highly conserved enzyme that is readily recognized during infection by the host antibody response. Secondly, we re-addressed a vaccine approach towards the Invariant Surface Glycoprotein ISG75, and showed that despite being highly immunogenic, trypanosomes can avoid anti-ISG75 mediated parasitemia control.
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Affiliation(s)
- Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Correspondence:
| | - Zeng Li
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Hang Thi Thu Nguyen
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
- Department of Biochemistry and Microbiology, Ghent University, Ledeganckstraat 35, 9000 Ghent, Belgium
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
| | - Joar Esteban Pinto Torres
- Laboratory of Cellular and Molecular Immunology, Department of Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium; (Z.L.); (H.T.T.N.); (J.E.P.T.)
| | - Pieter Van Wielendaele
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Department of Molecular Biotechnology, Environment Technology and Food Technology, Ghent University Global Campus, Songdomunhwa-Ro 119-5, Yeonsu-Gu, Incheon 406-840, Korea;
- Department of Biomedical Molecular Biology, Ghent University, Technologiepark Zwijnaarde 71, 9000 Ghent, Belgium
| | - Jakub Began
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Sebastian Zoll
- Laboratory of Structural Parasitology, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo Namesti 2, 16610 Prague 6, Czech Republic; (J.B.); (S.Z.)
| | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry (LMB) and the Infla-Med Centre of Excellence, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk, Belgium; (P.V.W.); (Y.G.-J.S.)
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17
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Garrison P, Umaer K, Bangs JD. The role of glycosylphosphatidylinositol phospholipase C in membrane trafficking in Trypanosoma brucei. Mol Biochem Parasitol 2021; 245:111409. [PMID: 34363902 DOI: 10.1016/j.molbiopara.2021.111409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/29/2021] [Accepted: 08/03/2021] [Indexed: 11/25/2022]
Abstract
Glycosylphosphatidylinositol-phospholipase C (GPI-PLC) is an enzyme that has been implicated in GPI-dependent protein trafficking and phosphoinositide metabolism in the bloodstream stage of African trypanosomes. However, despite the fact that it is associated with the cytoplasmic face of internal organellar compartments, its role in general membrane trafficking has not been investigated. Using a GPI-PLC null cell line, we determine the effect of GPI-PLC deficiency on these processes. Biosynthetic trafficking of lysosomal cargo, soluble cathepsin L and membrane bound p67, are unaffected. Likewise, secretory transport, recycling and ultimate lysosomal turnover of the GPI-anchored and transmembrane glycoproteins, transferrin receptor and invariant surface glycoprotein 65, respectively, were unaffected. A significant decrease in the endocytic uptake of transferrin was observed, confirming a prior report, but ultimate delivery to the lysosome was unimpacted. These results contribute to our understanding of the roles of this enigmatic enzyme in trypanosome cell biology.
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Affiliation(s)
- Paige Garrison
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14214, USA
| | - Khan Umaer
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14214, USA
| | - James D Bangs
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, NY, 14214, USA.
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18
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Nanotechnological interventions for treatment of trypanosomiasis in humans and animals. Drug Deliv Transl Res 2021; 10:945-961. [PMID: 32383004 DOI: 10.1007/s13346-020-00764-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Trypanosomiasis is a parasitic infection caused by Trypanosoma. It is one of the major causes of deaths in underprivileged, rural areas of Africa, America and Asia. Depending on the parasite species responsible for the disease, it can take two forms namely African trypanosomiasis (sleeping sickness) and American trypanosomiasis (Chagas disease). The complete life-cycle stages of trypanosomes span between insect vector (tsetse fly, triatomine bug) and mammalian host (humans, animals). Only few drugs have been approved for the treatment of trypanosomiasis. Moreover, current trypanocidal therapy has major limitations of poor efficacy, serious side effects and drug resistance. Due to the lack of economic gains from tropical parasitic infection, it has always been neglected by the researchers and drug manufacturers. There is an immense need of more effective innovative strategies to decrease the deaths associated with this diseases. Nanotechnological approaches for delivery of existing drugs have shown significant improvement in efficacy with many-fold decrease in their dose. The review emphasizes on nanotechnological interventions in the treatment of trypanosomiasis in both humans and animals. Current trypanocidal therapy and their limitations have also been discussed briefly. Graphical abstract.
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Abstract
African trypanosomes utilize glycosylphosphatidylinositol (GPI)-anchored variant surface glycoprotein (VSG) to evade the host immune system. VSG turnover is thought to be mediated via cleavage of the GPI anchor by endogenous GPI-specific phospholipase C (GPI-PLC). However, GPI-PLC is topologically sequestered from VSG substrates in intact cells. Recently, A. J. Szempruch, S. E. Sykes, R. Kieft, L. Dennison, et al. (Cell 164:246–257, 2016, https://doi.org/10.1016/j.cell.2015.11.051) demonstrated the release of nanotubes that septate to form free VSG+ extracellular vesicles (EVs). Here, we evaluated the relative contributions of GPI hydrolysis and EV formation to VSG turnover in wild-type (WT) and GPI-PLC null cells. The turnover rate of VSG was consistent with prior measurements (half-life [t1/2] of ∼26 h) but dropped significantly in the absence of GPI-PLC (t1/2 of ∼36 h). Ectopic complementation restored normal turnover rates, confirming the role of GPI-PLC in turnover. However, physical characterization of shed VSG in WT cells indicated that at least 50% is released directly from cell membranes with intact GPI anchors. Shedding of EVs plays an insignificant role in total VSG turnover in both WT and null cells. In additional studies, GPI-PLC was found to have no role in biosynthetic and endocytic trafficking to the lysosome but did influence the rate of receptor-mediated endocytosis. These results indicate that VSG turnover is a bimodal process involving both direct shedding and GPI hydrolysis.
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20
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Umaer K, Aresta-Branco F, Chandra M, van Straaten M, Zeelen J, Lapouge K, Waxman B, Stebbins CE, Bangs JD. Dynamic, variable oligomerization and the trafficking of variant surface glycoproteins of Trypanosoma brucei. Traffic 2021; 22:274-283. [PMID: 34101314 DOI: 10.1111/tra.12806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/14/2021] [Accepted: 06/04/2021] [Indexed: 12/20/2022]
Abstract
African trypanosomes cause disease in humans and livestock, avoiding host immunity by changing the expression of variant surface glycoproteins (VSGs); the major glycosylphosphatidylinositol (GPI) anchored antigens coating the surface of the bloodstream stage. Proper trafficking of VSGs is therefore critical to pathogen survival. The valence model argues that GPI anchors regulate progression and fate in the secretory pathway and that, specifically, a valence of two (VSGs are dimers) is critical for stable cell surface association. However, recent reports that the MITat1.3 (M1.3) VSG N-terminal domain (NTD) behaves as a monomer in solution and in a crystal structure challenge this model. We now show that the behavior of intact M1.3 VSG in standard in vivo trafficking assays is consistent with an oligomer. Nevertheless, Blue Native Gel electrophoresis and size exclusion chromatography-multiangle light scattering chromatography of purified full length M1.3 VSG indicates a monomer in vitro. However, studies with additional VSGs show that multiple oligomeric states are possible, and that for some VSGs oligomerization is concentration dependent. These data argue that individual VSG monomers possess different propensities to self-oligomerize, but that when constrained at high density to the cell surface, oligomeric species predominate. These results resolve the apparent conflict between the valence hypothesis and the M1.3 NTD VSG crystal structure.
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Affiliation(s)
- Khan Umaer
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA.,Eurofins, Spring House, Pennsylvania, USA
| | - Francisco Aresta-Branco
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany.,Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany
| | - Monica Chandra
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany.,Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
| | - Monique van Straaten
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Johan Zeelen
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Karine Lapouge
- Protein Expression and Purification Core Facility, EMBL Heidelberg, Heidelberg, Germany
| | - Brandon Waxman
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
| | - C Erec Stebbins
- Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - James D Bangs
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York, USA
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21
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Mishra A, Kaur JN, McSkimming DI, Hegedűsová E, Dubey AP, Ciganda M, Paris Z, Read LK. Selective nuclear export of mRNAs is promoted by DRBD18 in Trypanosoma brucei. Mol Microbiol 2021; 116:827-840. [PMID: 34146438 DOI: 10.1111/mmi.14773] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 06/04/2021] [Accepted: 06/18/2021] [Indexed: 11/27/2022]
Abstract
Kinetoplastids, including Trypanosoma brucei, control gene expression primarily at the posttranscriptional level. Nuclear mRNA export is an important, but understudied, step in this process. The general heterodimeric export factors, Mex67/Mtr2, function in the export of mRNAs and tRNAs in T. brucei, but RNA binding proteins (RBPs) that regulate export processes by controlling the dynamics of Mex67/Mtr2 ribonucleoprotein formation or transport have not been identified. Here, we report that DRBD18, an essential and abundant T. brucei RBP, associates with Mex67/Mtr2 in vivo, likely through its direct interaction with Mtr2. DRBD18 downregulation results in partial accumulation of poly(A)+ mRNA in the nucleus, but has no effect on the localization of intron-containing or mature tRNAs. Comprehensive analysis of transcriptomes from whole-cell and cytosol in DRBD18 knockdown parasites demonstrates that depletion of DRBD18 leads to impairment of nuclear export of a subset of mRNAs. CLIP experiments reveal the association of DRBD18 with several of these mRNAs. Moreover, DRBD18 knockdown leads to a partial accumulation of the Mex67/Mtr2 export receptors in the nucleus. Taken together, the current study supports a model in which DRBD18 regulates the selective nuclear export of mRNAs by promoting the mobilization of export competent mRNPs to the cytosol through the nuclear pore complex.
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Affiliation(s)
- Amartya Mishra
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jan Naseer Kaur
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Daniel I McSkimming
- Bioinformatics and Computational Biology Core, University of Southern Florida, Tampa, FL, USA
| | - Eva Hegedűsová
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
| | - Ashutosh P Dubey
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Martin Ciganda
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Laurie K Read
- Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA
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22
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African Trypanosomosis Obliterates DTPa Vaccine-Induced Functional Memory So That Post-Treatment Bordetella pertussis Challenge Fails to Trigger a Protective Recall Response. Vaccines (Basel) 2021; 9:vaccines9060603. [PMID: 34200074 PMCID: PMC8230080 DOI: 10.3390/vaccines9060603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 11/17/2022] Open
Abstract
Salivarian trypanosomes are extracellular parasites causing anthroponotic and zoonotic infections. Anti-parasite vaccination is considered the only sustainable method for global trypanosomosis control. Unfortunately, no single field applicable vaccine solution has been successful so far. The active destruction of the host’s adaptive immune system by trypanosomes is believed to contribute to this problem. Here, we show that Trypanosome brucei brucei infection results in the lasting obliteration of immunological memory, including vaccine-induced memory against non-related pathogens. Using the well-established DTPa vaccine model in combination with a T. b. brucei infection and a diminazene diaceturate anti-parasite treatment scheme, our results demonstrate that while the latter ensured full recovery from the T. b. brucei infection, it failed to restore an efficacious anti-B. pertussis vaccine recall response. The DTPa vaccine failure coincided with a shift in the IgG1/IgG2a anti-B. pertussis antibody ratio in favor of IgG2a, and a striking impact on all of the spleen immune cell populations. Interestingly, an increased plasma IFNγ level in DTPa-vaccinated trypanosome-infected mice coincided with a temporary antibody-independent improvement in early-stage trypanosomosis control. In conclusion, our results are the first to show that trypanosome-inflicted immune damage is not restored by successful anti-parasite treatment.
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23
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Salivarian Trypanosomes Have Adopted Intricate Host-Pathogen Interaction Mechanisms That Ensure Survival in Plain Sight of the Adaptive Immune System. Pathogens 2021; 10:pathogens10060679. [PMID: 34072674 PMCID: PMC8229994 DOI: 10.3390/pathogens10060679] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 05/24/2021] [Accepted: 05/28/2021] [Indexed: 12/21/2022] Open
Abstract
Salivarian trypanosomes are extracellular parasites affecting humans, livestock and game animals. Trypanosoma brucei rhodesiense and Trypanosoma brucei gambiense are human infective sub-species of T. brucei causing human African trypanosomiasis (HAT—sleeping sickness). The related T. b. brucei parasite lacks the resistance to survive in human serum, and only inflicts animal infections. Animal trypanosomiasis (AT) is not restricted to Africa, but is present on all continents. T. congolense and T. vivax are the most widespread pathogenic trypanosomes in sub-Saharan Africa. Through mechanical transmission, T. vivax has also been introduced into South America. T. evansi is a unique animal trypanosome that is found in vast territories around the world and can cause atypical human trypanosomiasis (aHT). All salivarian trypanosomes are well adapted to survival inside the host’s immune system. This is not a hostile environment for these parasites, but the place where they thrive. Here we provide an overview of the latest insights into the host-parasite interaction and the unique survival strategies that allow trypanosomes to outsmart the immune system. In addition, we review new developments in treatment and diagnosis as well as the issues that have hampered the development of field-applicable anti-trypanosome vaccines for the implementation of sustainable disease control.
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24
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Nihei CI, Nakanishi M. Cargo selection in the early secretory pathway of African trypanosomes. Parasitol Int 2021; 84:102379. [PMID: 34000424 DOI: 10.1016/j.parint.2021.102379] [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: 12/21/2020] [Revised: 03/30/2021] [Accepted: 05/06/2021] [Indexed: 11/25/2022]
Abstract
Membrane and secretory proteins are synthesized by ribosomes and then enter the endoplasmic reticulum (ER) where they undergo glycosylation and quality control for proper folding. Subsequently, proteins are transported to the Golgi apparatus and then sorted to the plasma membrane or intracellular organelles. Transport vesicles are formed at ER-exit sites (ERES) on the ER with several coat protein complexes. Cargo proteins loaded into the vesicles are selected by specific interactions with cargo receptors and/or adaptors during vesicle formation. p24 family and intracellular lectin ERGIC-53-membrane proteins are the known cargo receptors acting in the early secretory pathway (ER-Golgi). Oligomerization of the cargo receptors have been suggested to play an important role in cargo selection and sorting via posttranslational modifications in fungi and metazoans. On the other hand, the mechanisms involved in the early secretory pathway in protozoa remain unclear. In this review, we focus on Trypanosoma brucei as a representative of protozoan and discuss differences and commonalities in the molecular mechanisms of its early secretory pathway compared with other organisms.
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Affiliation(s)
- Coh-Ichi Nihei
- Institute of Microbial Chemistry, Microbial Chemistry Research Foundation (BIKAKEN), 3-14-23, Kamiosaki, Shinagawa-ku, Tokyo 141-0023, Japan.
| | - Masayuki Nakanishi
- Laboratory of Biochemistry, College of Pharmaceutical Sciences, Matsuyama University, Matsuyama, Ehime 790-8578, Japan.
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25
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Davies C, Ooi CP, Sioutas G, Hall BS, Sidhu H, Butter F, Alsford S, Wickstead B, Rudenko G. TbSAP is a novel chromatin protein repressing metacyclic variant surface glycoprotein expression sites in bloodstream form Trypanosoma brucei. Nucleic Acids Res 2021; 49:3242-3262. [PMID: 33660774 PMCID: PMC8034637 DOI: 10.1093/nar/gkab109] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 02/02/2021] [Accepted: 02/11/2021] [Indexed: 12/13/2022] Open
Abstract
The African trypanosome Trypanosoma brucei is a unicellular eukaryote, which relies on a protective variant surface glycoprotein (VSG) coat for survival in the mammalian host. A single trypanosome has >2000 VSG genes and pseudogenes of which only one is expressed from one of ∼15 telomeric bloodstream form expression sites (BESs). Infectious metacyclic trypanosomes present within the tsetse fly vector also express VSG from a separate set of telomeric metacyclic ESs (MESs). All MESs are silenced in bloodstream form T. brucei. As very little is known about how this is mediated, we performed a whole genome RNAi library screen to identify MES repressors. This allowed us to identify a novel SAP domain containing DNA binding protein which we called TbSAP. TbSAP is enriched at the nuclear periphery and binds both MESs and BESs. Knockdown of TbSAP in bloodstream form trypanosomes did not result in cells becoming more ‘metacyclic-like'. Instead, there was extensive global upregulation of transcripts including MES VSGs, VSGs within the silent VSG arrays as well as genes immediately downstream of BES promoters. TbSAP therefore appears to be a novel chromatin protein playing an important role in silencing the extensive VSG repertoire of bloodstream form T. brucei.
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Affiliation(s)
- Carys Davies
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Cher-Pheng Ooi
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Georgios Sioutas
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Belinda S Hall
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Haneesh Sidhu
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Falk Butter
- Institute of Molecular Biology, Ackermannweg 4, 55128 Mainz, Germany
| | - Sam Alsford
- London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Bill Wickstead
- School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK
| | - Gloria Rudenko
- Sir Alexander Fleming Building, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
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26
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Structure of trypanosome coat protein VSGsur and function in suramin resistance. Nat Microbiol 2021; 6:392-400. [PMID: 33462435 PMCID: PMC7116837 DOI: 10.1038/s41564-020-00844-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 11/30/2020] [Indexed: 01/28/2023]
Abstract
Suramin has been a primary early-stage treatment for African trypanosomiasis for nearly 100 yr. Recent studies revealed that trypanosome strains that express the variant surface glycoprotein (VSG) VSGsur possess heightened resistance to suramin. Here, we show that VSGsur binds tightly to suramin but other VSGs do not. By solving high-resolution crystal structures of VSGsur and VSG13, we also demonstrate that these VSGs define a structurally divergent subgroup of the coat proteins. The co-crystal structure of VSGsur with suramin reveals that the chemically symmetric drug binds within a large cavity in the VSG homodimer asymmetrically, primarily through contacts of its central benzene rings. Structure-based, loss-of-contact mutations in VSGsur significantly decrease the affinity to suramin and lead to a loss of the resistance phenotype. Altogether, these data show that the resistance phenotype is dependent on the binding of suramin to VSGsur, establishing that the VSG proteins can possess functionality beyond their role in antigenic variation.
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27
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Valotteau C, Dumitru AC, Lecordier L, Alsteens D, Pays E, Pérez-Morga D, Dufrêne YF. Multiparametric Atomic Force Microscopy Identifies Multiple Structural and Physical Heterogeneities on the Surface of Trypanosoma brucei. ACS OMEGA 2020; 5:20953-20959. [PMID: 32875230 PMCID: PMC7450619 DOI: 10.1021/acsomega.0c02416] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/01/2020] [Indexed: 05/30/2023]
Abstract
A unique feature of the African trypanosome Trypanosoma brucei is the presence of an outer layer made of densely packed variable surface glycoproteins (VSGs), which enables the cells to survive in the bloodstream. Although the VSG coat is critical to pathogenesis, how exactly the glycoproteins are organized at the nanoscale is poorly understood. Here, we show that multiparametric atomic force microscopy is a powerful nanoimaging tool for the structural and mechanical characterization of trypanosomes, in a label-free manner and in buffer solution. Directly correlated images of the structure and elasticity of trypanosomes enable us to identify multiple nanoscale mechanical heterogeneities on the cell surface. On a ∼250 nm scale, regions of softer (Young's modulus ∼50 kPa) and stiffer (∼100 kPa) elasticity alternate, revealing variations of the VSG coat and underlying structures. Our nanoimaging experiments show that the T. brucei cell surface is more heterogeneous than previously anticipated and offer promising prospects for the design of trypanocidal drugs targeting cell surface components.
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Affiliation(s)
- Claire Valotteau
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Andra C. Dumitru
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Laurence Lecordier
- Laboratory
of Molecular Parasitology, IBMM, Université
Libre de Bruxelles, 12
rue des professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - David Alsteens
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
| | - Etienne Pays
- Laboratory
of Molecular Parasitology, IBMM, Université
Libre de Bruxelles, 12
rue des professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - David Pérez-Morga
- Laboratory
of Molecular Parasitology, IBMM, Université
Libre de Bruxelles, 12
rue des professeurs Jeener et Brachet, B-6041 Gosselies, Belgium
| | - Yves F. Dufrêne
- Louvain
Institute of Biomolecular Science and Technology, UCLouvain, Croix du Sud, 4-5, bte L7.07.07, B-1348 Louvain-la-Neuve, Belgium
- Walloon
Excellence in Life sciences and Biotechnology (WELBIO), B-1300 Wavre, Belgium
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28
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Romero-Meza G, Mugnier MR. Trypanosoma brucei. Trends Parasitol 2019; 36:571-572. [PMID: 31757771 DOI: 10.1016/j.pt.2019.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/18/2019] [Indexed: 12/29/2022]
Affiliation(s)
- Gabriela Romero-Meza
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
| | - Monica R Mugnier
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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29
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Abstract
The investigation of the glycan repertoire of several organisms has revealed a wide variation in terms of structures and abundance of glycan moieties. Among the parasites, it is possible to observe different sets of glycoconjugates across taxa and developmental stages within a species. The presence of distinct glycoconjugates throughout the life cycle of a parasite could relate to the ability of that organism to adapt and survive in different hosts and environments. Carbohydrates on the surface, and in excretory-secretory products of parasites, play essential roles in host-parasite interactions. Carbohydrate portions of complex molecules of parasites stimulate and modulate host immune responses, mainly through interactions with specific receptors on the surface of dendritic cells, leading to the generation of a pattern of response that may benefit parasite survival. Available data reviewed here also show the frequent aspect of parasite immunomodulation of mammalian responses through specific glycan interactions, which ultimately makes these molecules promising in the fields of diagnostics and vaccinology.
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