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Eberhard JN, Shallberg LA, Winn A, Chandrasekaran S, Giuliano CJ, Merritt EF, Willis E, Konradt C, Christian DA, Aldridge DL, Bunkofske ME, Jacquet M, Dzierszinski F, Katifori E, Lourido S, Koshy AA, Hunter CA. Immune targeting and host-protective effects of the latent stage of Toxoplasma gondii. Nat Microbiol 2025; 10:992-1005. [PMID: 40148566 PMCID: PMC11964939 DOI: 10.1038/s41564-025-01967-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 02/19/2025] [Indexed: 03/29/2025]
Abstract
Latency is a microbial strategy for persistence. For Toxoplasma gondii the bradyzoite stage forms long-lived cysts critical for transmission, and its presence in neurons is considered important for immune evasion. However, the extent to which cyst formation escapes immune pressure and mediates persistence remained unclear. Here we developed a mathematical model highlighting that bradyzoite-directed immunity contributes to control of cyst numbers. In vivo studies demonstrated that transgenic CD8+ T cells recognized a cyst-derived antigen, and neuronal STAT1 signalling promoted cyst control in mice. Modelling and experiments with parasites unable to form bradyzoites (Δbfd1) revealed that the absence of cyst formation in the central nervous system did not prevent long-term persistence but resulted in increased tachyzoite replication with associated tissue damage and mortality. These findings suggest the latent form of T. gondii is under immune pressure, mitigates infection-induced damage and promotes survival of host and parasite.
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Affiliation(s)
- Julia N Eberhard
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lindsey A Shallberg
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Aaron Winn
- Department of Physics and Astronomy, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Christopher J Giuliano
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Emily F Merritt
- Department of Immunology, University of Arizona, Tucson, AZ, USA
| | - Elinor Willis
- Comparative Pathology Core, Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Christoph Konradt
- Department of Comparative Pathobiology, Purdue University College of Veterinary Medicine, West Lafayette, IN, USA
| | - David A Christian
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Daniel L Aldridge
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Molly E Bunkofske
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Maxime Jacquet
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Florence Dzierszinski
- The Royal Ottawa Mental Health Center, Institute of Mental Health Research, Ottawa, Ontario, Canada
| | - Eleni Katifori
- Department of Physics and Astronomy, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Center for Computational Biology, Flatiron Institute, New York, NY, USA
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research, Cambridge, MA, USA
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Anita A Koshy
- BIO5 Institute, University of Arizona, Tucson, AZ, USA
- Department of Immunology, University of Arizona, Tucson, AZ, USA
- Department of Neurology, University of Arizona, Tucson, AZ, USA
| | - Christopher A Hunter
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Wendo JK, Mbaria JM, Nyariki JN, Isaac AO. Ginkgo biloba attenuated detrimental inflammatory and oxidative events due to Trypanosoma brucei rhodesiense in mice treated with melarsoprol. PLoS Negl Trop Dis 2024; 18:e0012103. [PMID: 38620045 PMCID: PMC11045140 DOI: 10.1371/journal.pntd.0012103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 04/25/2024] [Accepted: 03/25/2024] [Indexed: 04/17/2024] Open
Abstract
BACKGROUND The severe late stage Human African Trypanosomiasis (HAT) caused by Trypanosoma brucei rhodesiense (T.b.r) is characterized by damage to the blood brain barrier, severe brain inflammation, oxidative stress and organ damage. Melarsoprol (MelB) is currently the only treatment available for this disease. MelB use is limited by its lethal neurotoxicity due to post-treatment reactive encephalopathy. This study sought to assess the potential of Ginkgo biloba (GB), a potent anti-inflammatory and antioxidant, to protect the integrity of the blood brain barrier and ameliorate detrimental inflammatory and oxidative events due to T.b.r in mice treated with MelB. METHODOLOGY Group one constituted the control; group two was infected with T.b.r; group three was infected with T.b.r and treated with 2.2 mg/kg melarsoprol for 10 days; group four was infected with T.b.r and administered with GB 80 mg/kg for 30 days; group five was given GB 80mg/kg for two weeks before infection with T.b.r, and continued thereafter and group six was infected with T.b.r, administered with GB and treated with MelB. RESULTS Co-administration of MelB and GB improved the survival rate of infected mice. When administered separately, MelB and GB protected the integrity of the blood brain barrier and improved neurological function in infected mice. Furthermore, the administration of MelB and GB prevented T.b.r-induced microcytic hypochromic anaemia and thrombocytopenia, as well as T.b.r-driven downregulation of total WBCs. Glutathione analysis showed that co-administration of MelB and GB prevented T.b.r-induced oxidative stress in the brain, spleen, heart and lungs. Notably, GB averted peroxidation and oxidant damage by ameliorating T.b.r and MelB-driven elevation of malondialdehyde (MDA) in the brain, kidney and liver. In fact, the co-administered group for the liver, registered the lowest MDA levels for infected mice. T.b.r-driven elevation of serum TNF-α, IFN-γ, uric acid and urea was abrogated by MelB and GB. Co-administration of MelB and GB was most effective in stabilizing TNFα levels. GB attenuated T.b.r and MelB-driven up-regulation of nitrite. CONCLUSION Utilization of GB as an adjuvant therapy may ameliorate detrimental effects caused by T.b.r infection and MelB toxicity during late stage HAT.
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Affiliation(s)
- Janet Khatenje Wendo
- The University of Nairobi, Department of Public Health, Pharmacology and Toxicology, Kangemi (Nairobi), Kenya
- The Technical University of Kenya, Department of Pharmaceutical Sciences and Technology, Nairobi, Kenya
| | - James Mucunu Mbaria
- The University of Nairobi, Department of Public Health, Pharmacology and Toxicology, Kangemi (Nairobi), Kenya
| | - James Nyabuga Nyariki
- The Technical University of Kenya, Department of Biochemistry and Biotechnology, Nairobi, Kenya
| | - Alfred Orina Isaac
- The Technical University of Kenya, Department of Pharmaceutical Sciences and Technology, Nairobi, Kenya
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Guo G, Lin Y, Zhu X, Ding F, Xue X, Zhang Q. Emerging roles of the epitranscriptome in parasitic protozoan biology and pathogenesis. Trends Parasitol 2024; 40:214-229. [PMID: 38355313 DOI: 10.1016/j.pt.2024.01.006] [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: 11/12/2023] [Revised: 01/16/2024] [Accepted: 01/17/2024] [Indexed: 02/16/2024]
Abstract
RNA modifications (epitranscriptome) - such as N6-methyladenosine (m6A), 5-methylcytosine (m5C), and pseudouridine (Ψ) - modulate RNA processing, stability, interaction, and translation, thereby playing critical roles in the development, replication, virulence, metabolism, and life cycle adaptations of parasitic protozoa. Here, we summarize potential homologs of the major human RNA modification regulatory factors in parasites, outline current knowledge on how RNA modifications affect parasitic protozoa, highlight the regulation of RNA modifications and their crosstalk, and discuss current progress in exploring RNA modifications as potential drug targets. This review contributes to our understanding of epitranscriptomic regulation of parasitic protozoa biology and pathogenesis and provides new perspectives for the treatment of parasitic diseases.
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Affiliation(s)
- Gangqiang Guo
- Wenzhou Collaborative Innovation Center of Gastrointestinal Cancer in Basic Research and Precision Medicine, Wenzhou Key Laboratory of Cancer-related Pathogens and Immunity, Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Yutong Lin
- First Clinical College, Wenzhou Medical University, Wenzhou, China
| | - Xinqi Zhu
- First Clinical College, Wenzhou Medical University, Wenzhou, China
| | - Feng Ding
- Department of Microbiology and Immunology, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China
| | - Xiangyang Xue
- Wenzhou Collaborative Innovation Center of Gastrointestinal Cancer in Basic Research and Precision Medicine, Wenzhou Key Laboratory of Cancer-related Pathogens and Immunity, Department of Microbiology and Immunology, Institute of Molecular Virology and Immunology, Institute of Tropical Medicine, School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, China.
| | - Qingfeng Zhang
- Laboratory of Molecular Parasitology, State Key Laboratory of Cardiology and Research Center for Translational Medicine, Shanghai East Hospital; Clinical Center for Brain and Spinal Cord Research, School of Medicine, Tongji University, Shanghai 200120, China.
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Choi B, Vu HT, Vu HT, Radwanska M, Magez S. Advances in the Immunology of the Host-Parasite Interactions in African Trypanosomosis, including Single-Cell Transcriptomics. Pathogens 2024; 13:188. [PMID: 38535532 PMCID: PMC10975194 DOI: 10.3390/pathogens13030188] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/11/2025] Open
Abstract
Trypanosomes are single-celled extracellular parasites that infect mammals, including humans and livestock, causing global public health concerns and economic losses. These parasites cycle between insect vectors, such as tsetse flies and vertebrate hosts, undergoing morphological, cellular, and biochemical changes. They have remarkable immune evasion mechanisms to escape the host's innate and adaptive immune responses, such as surface coat antigenic variation and the induction of the loss of specificity and memory of antibody responses, enabling the prolongation of infection. Since trypanosomes circulate through the host body in blood and lymph fluid and invade various organs, understanding the interaction between trypanosomes and tissue niches is essential. Here, we present an up-to-date overview of host-parasite interactions and survival strategies for trypanosomes by introducing and discussing the latest studies investigating the transcriptomics of parasites according to life cycle stages, as well as host cells in various tissues and organs, using single-cell and spatial sequencing applications. In recent years, this information has improved our understanding of trypanosomosis by deciphering the diverse populations of parasites in the developmental process, as well as the highly heterogeneous immune and tissue-resident cells involved in anti-trypanosome responses. Ultimately, the goal of these approaches is to gain an in-depth understanding of parasite biology and host immunity, potentially leading to new vaccination and therapeutic strategies against trypanosomosis.
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Affiliation(s)
- Boyoon Choi
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (B.C.); (H.T.V.); (H.T.V.); (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
| | - Hien Thi Vu
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (B.C.); (H.T.V.); (H.T.V.); (M.R.)
- Department of Biomedical Molecular Biology WE14, Ghent University, 9052 Ghent, Belgium
| | - Hai Thi Vu
- Laboratory for Biomedical Research, Department of Environmental Technology, Food Technology and Molecular Biotechnology KR01, Ghent University Global Campus, Incheon 21985, Republic of Korea; (B.C.); (H.T.V.); (H.T.V.); (M.R.)
- Department of Biomedical Molecular Biology WE14, Ghent University, 9052 Ghent, 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; (B.C.); (H.T.V.); (H.T.V.); (M.R.)
- Department of Biomedical Molecular Biology WE14, Ghent University, 9052 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; (B.C.); (H.T.V.); (H.T.V.); (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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Oula JO, Mose JM, Waiganjo NN, Chepukosi KW, Mitalo NS, Isaac AO, Nyariki JN. Vitamin B12 blocked Trypanosoma brucei rhodesiense-driven disruption of the blood brain barrier, and normalized nitric oxide and malondialdehyde levels in a mouse model. Parasitol Int 2023; 96:102775. [PMID: 37390918 DOI: 10.1016/j.parint.2023.102775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 06/20/2023] [Accepted: 06/27/2023] [Indexed: 07/02/2023]
Abstract
Infection with Trypanosoma brucei rhodesiense (T.b.r) causes acute Human African Trypanosomiasis (HAT) in Africa. This study determined the effect of vitamin B12 on T.b.r -driven pathological events in a mouse model. Mice were randomly assigned into four groups; group one was the control. Group two was infected with T.b.r; group three was supplemented with 8 mg/kg vitamin B12 for two weeks; before infection with T.b.r. For group four, administration of vitamin B12 was started from the 4th days post-infection with T.b.r. At 40 days post-infection, the mice were sacrificed to obtain blood, tissues, and organs for various analyses. The results showed that vitamin B12 administration enhanced the survival rate of T.b.r infected mice, and prevented T.b.r-induced disruption of the blood-brain barrier and decline in neurological performance. Notably, T.b.r-induced hematological alteration leading to anaemia, leukocytosis and dyslipidemia was alleviated by vitamin B12. T.b.r-induced elevation of the liver alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and total bilirubin as well as the kidney damage markers urea, uric acid and creatinine were attenuated by vitamin B12. Vitamin B12 blocked T.b.r-driven rise in TNF-α and IFN-γ, nitric oxide and malondialdehyde. T.b.r-induced depletion of GSH levels were attenuated in the presence of vitamin B12 in the brain, spleen and liver tissues; a clear indication of the antioxidant activity of vitamin B12. In conclusion, treatment with vitamin B12 potentially protects against various pathological events associated with severe late-stage HAT and presents a great opportunity for further scrutiny to develop an adjunct therapy for severe late-stage HAT.
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Affiliation(s)
- James O Oula
- Department of Biomedical Science & Technology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - John Mokua Mose
- Department of Biomedical Science & Technology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - Naomi N Waiganjo
- Department of Biomedical Science & Technology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - Kennedy W Chepukosi
- Department of Biochemistry and Biotechnology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - Nancy S Mitalo
- Department of Biomedical Science & Technology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - Alfred Orina Isaac
- Department of Pharmaceutical Sciences and Technology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya
| | - James Nyabuga Nyariki
- Department of Biochemistry and Biotechnology, Technical University of Kenya, P. O. Box 52428, 00200 Nairobi, Kenya.
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Kitwan L, Makobe C, Mdachi R, Maranga DN, Isaac AO, Nyariki JN. Coenzyme Q 10 prevented Trypanosoma brucei rhodesiense-mediated breach of the blood brain barrier, inflammation and organ damage in late stage of Human African Trypanosomiasis. J Parasit Dis 2023; 47:167-184. [PMID: 36910316 PMCID: PMC9998817 DOI: 10.1007/s12639-022-01553-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 11/21/2022] [Indexed: 12/05/2022] Open
Abstract
During the late stage of Human African Trypanosomiasis (HAT), there is severe cytokine-driven inflammation, oxidative stress and organ damage. Controlling inflammation and oxidative damage presents unique therapeutic opportunities to improve treatment outcome. The current study sought to determine the putative impact of Coenzyme-Q10 (Co-Q10), a potent antioxidant and anti-inflammatory, on adverse inflammatory and oxidative events during Trypanosoma brucei rhodesiense (T.b.r) infection. Group one constituted the control; the second group was infected with T.b.r; the third group was orally administered with 200 mg/kg Co-Q10 for two weeks; thereafter, Co-Q10 administration continued after infection with T.b.r. Co-Q10 improved the survival rate of infected mice and prevented full blown parasite driven splenomegaly and hepatomegaly. Co-Q10 prevented characteristic T.b.r-driven breach of the blood brain barrier and improved neurological integrity among T.b.r infected mice. Co-Q10 protected from T.b.r-induced microcytic hypochromic anaemia and thrombocytopenia. T.b.r-induced oxidative stress in the vital organs was assuaged following exposure to Co-Q10. Co-Q10 blocked T.b.r-induced derangement of high density lipoprotein and triglyceride levels. Co-Q10 significantly abrogated T.b.r-driven elevation of serum TNF-α and IFN-γ levels. Moreover, T.b.r-induced kidney and liver damage was assuaged by Co-Q10 administration. Co-Q10 administration downregulated T.b.r-induced elevation of uric acid and C-reactive protein. Likewise, T.b.r infected mice receiving Co-Q10 exhibited normal brain architecture. In conclusion, treatment with Co-Q10 may be useful in protecting against T.b.r-mediated organ injury, lethal inflammation and oxidative stress commonly present in severe late stage HAT; and presents unique opportunities for an adjunct therapy for late stage HAT.
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Affiliation(s)
- Lynn Kitwan
- Department of Medical Microbiology Department, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Celestine Makobe
- Department of Medical Microbiology Department, Jomo Kenyatta University of Agriculture and Technology (JKUAT), Nairobi, Kenya
| | - Raymond Mdachi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | | | - Alfred Orina Isaac
- Department of Pharmaceutical Sciences and Technology, Technical University of Kenya, Nairobi, Kenya
| | - James Nyabuga Nyariki
- Department of Biochemistry and Biotechnology, Technical University of Kenya, Nairobi, Kenya
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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
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8
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Couto LFM, Heller LM, Zapa DMB, de Moura MI, Costa GL, de Assis Cavalcante AS, Ribeiro NB, Bastos TSA, Ferreira LL, Soares VE, Lino de Souza GR, Cadioli FA, Lopes WDZ. Presence of Trypanosoma vivax DNA in cattle semen and reproductive tissues and related changes in sperm parameters. Vet Parasitol 2022; 309:109761. [PMID: 35843131 DOI: 10.1016/j.vetpar.2022.109761] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/03/2022] [Accepted: 07/02/2022] [Indexed: 11/19/2022]
Abstract
The present work investigated the presence of Trypanosoma vivax in semen and reproductive tissues of experimentally infected cattle and evaluated changes in seminal parameters. Two groups of cattle were established: T01 - experimentally infected with T. vivax (n = 8) and T02 - not experimentally infected with T. vivax (n = 8). After infection, blood (every seven days until 182 days post-infection - DPI), semen (7, 14, 35, 56, 70, 120 and 182 DPI) and reproductive tissue (after euthanasia, 182 DPI) were collected to search for T. vivax using different techniques, including PCR, Woo and Brener. Seminal parameters, including turbulence, motility, concentration, and vigor, were also analyzed. Packed cell volume (PCV) of the animals was determined weekly and weight gain was calculated. The PCR revealed T. vivax DNA in 7/56 semen samples of post-infection T01 cattle. Trypanosoma vivax DNA was detected in the semen of 5/8 animals at 7, 14, 56, 70 and 120 DPI, in the testis of four, and in the epididymis and fat located around the testis of two others. Trypomastigote forms of T. vivax were not found in any semen sample. Sperm of T01 cattle had lower turbulence (p ≤ 0.05) at 7, 14, 35, 56, 120 and 182 DPI, lower vigor (p ≤ 0.05) at 120 DPI and more sperm abnormalities (p ≤ 0.05) than T02. Digital dermatitis was observed among T01 cattle. Animals of T01 had lower PCV values than did those of T02 for most of the evaluations performed and T02 animals gained more weight during the experiment. The results highlight the presence of T. vivax DNA in semen of infected cattle and the importance of this disease for male breeding cattle. Further research is needed to determine whether T. vivax can be sexually transmitted in cattle.
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Affiliation(s)
| | - Luciana Maffini Heller
- Escola de Veterinária e Zootecnia, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | | | - Maria Ivete de Moura
- Professor Assistente. Pontifícia Universidade Católica Universidade Católica de Goiás Goiânia, Goiás, Brazil
| | - Gustavo Lage Costa
- Professor Assistente. Pontifícia Universidade Católica Universidade Católica de Goiás Goiânia, Goiás, Brazil
| | | | - Nathalia Braz Ribeiro
- Escola de Veterinária e Zootecnia, Universidade Federal de Goiás, Goiânia, Goiás, Brazil
| | | | - Lorena Lopes Ferreira
- Departamento de Medicina Veterinária Preventiva, Escola de Veterinária, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
| | | | | | - Fabiano Antônio Cadioli
- Departamento de Clínica, Cirurgia e Reprodução Animal, Faculdade de Medicina Veterinária, Universidade Estadual Paulista, Araçatuba, São Paulo, Brazil
| | - Welber Daniel Zanetti Lopes
- Escola de Veterinária e Zootecnia, Universidade Federal de Goiás, Goiânia, Goiás, Brazil; Departamento de Biociências e Tecnologia, Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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9
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Silva Pereira S, Jackson AP, Figueiredo LM. Evolution of the variant surface glycoprotein family in African trypanosomes. Trends Parasitol 2021; 38:23-36. [PMID: 34376326 DOI: 10.1016/j.pt.2021.07.012] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/21/2021] [Accepted: 07/22/2021] [Indexed: 01/22/2023]
Abstract
An intriguing and remarkable feature of African trypanosomes is their antigenic variation system, mediated by the variant surface glycoprotein (VSG) family and fundamental to both immune evasion and disease epidemiology within host populations. Recent studies have revealed that the VSG repertoire has a complex evolutionary history. Sequence diversity, genomic organization, and expression patterns are species-specific, which may explain other variations in parasite virulence and disease pathology. Evidence also shows that we may be underestimating the extent to what VSGs are repurposed beyond their roles as variant antigens, establishing a need to examine VSG functionality more deeply. Here, we review sequence variation within the VSG gene family, and highlight the many opportunities to explore their likely diverse contributions to parasite survival.
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Affiliation(s)
- Sara Silva Pereira
- Instituto de Medicina Molecular - João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Andrew P Jackson
- Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool L3 5RF, UK
| | - Luísa M Figueiredo
- Instituto de Medicina Molecular - João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal.
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10
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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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11
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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: 20] [Impact Index Per Article: 5.0] [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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12
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Ndung’u K, Murilla GA, Thuita JK, Ngae GN, Auma JE, Gitonga PK, Thungu DK, Kurgat RK, Chemuliti JK, Mdachi RE. Differential virulence of Trypanosoma brucei rhodesiense isolates does not influence the outcome of treatment with anti-trypanosomal drugs in the mouse model. PLoS One 2020; 15:e0229060. [PMID: 33151938 PMCID: PMC7643984 DOI: 10.1371/journal.pone.0229060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 07/04/2020] [Indexed: 11/19/2022] Open
Abstract
We assessed the virulence and anti-trypanosomal drug sensitivity patterns of Trypanosoma brucei rhodesiense (Tbr) isolates in the Kenya Agricultural and Livestock Research Organization-Biotechnology Research Institute (KALRO-BioRI) cryobank. Specifically, the study focused on Tbr clones originally isolated from the western Kenya/eastern Uganda focus of human African Trypanosomiasis (HAT). Twelve (12) Tbr clones were assessed for virulence using groups(n = 10) of Swiss White Mice monitored for 60 days post infection (dpi). Based on survival time, four classes of virulence were identified: (a) very-acute: 0-15, (b) acute: 16-30, (c) sub-acute: 31-45 and (d) chronic: 46-60 dpi. Other virulence biomarkers identified included: pre-patent period (pp), parasitaemia progression, packed cell volume (PCV) and body weight changes. The test Tbr clones together with KALRO-BioRi reference drug-resistant and drug sensitive isolates were then tested for sensitivity to melarsoprol (mel B), pentamidine, diminazene aceturate and suramin, using mice groups (n = 5) treated with single doses of each drug at 24 hours post infection. Our results showed that the clones were distributed among four classes of virulence as follows: 3/12 (very-acute), 3/12 (acute), 2/12 (sub-acute) and 4/12 (chronic) isolates. Differences in survivorship, parasitaemia progression and PCV were significant (P<0.001) and correlated. The isolate considered to be drug resistant at KALRO-BioRI, KETRI 2538, was confirmed to be resistant to melarsoprol, pentamidine and diminazene aceturate but it was not resistant to suramin. A cure rate of at least 80% was achieved for all test isolates with melarsoprol (1mg/Kg and 20 mg/kg), pentamidine (5 and 20 mg/kg), diminazene aceturate (5 mg/kg) and suramin (5 mg/kg) indicating that the isolates were not resistant to any of the drugs despite the differences in virulence. This study provides evidence of variations in virulence of Tbr clones from a single HAT focus and confirms that this variations is not a significant determinant of isolate sensitivity to anti-trypanosomal drugs.
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Affiliation(s)
- Kariuki Ndung’u
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- * E-mail:
| | - Grace Adira Murilla
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- KAG EAST University, Nairobi, Kenya
| | - John Kibuthu Thuita
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Meru University of Science and Technology, Meru, Kenya
| | - Geoffrey Njuguna Ngae
- Food Crops Research Institute, Kenya Agricultural and Livestock Research Organization, Nairobi, Kenya
| | - Joanna Eseri Auma
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Purity Kaari Gitonga
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Daniel Kahiga Thungu
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Richard Kiptum Kurgat
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Judith Kusimba Chemuliti
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Raymond Ellie Mdachi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
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13
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Faktorová D, Kaur B, Valach M, Graf L, Benz C, Burger G, Lukeš J. Targeted integration by homologous recombination enables in situ tagging and replacement of genes in the marine microeukaryote Diplonema papillatum. Environ Microbiol 2020; 22:3660-3670. [PMID: 32548939 DOI: 10.1111/1462-2920.15130] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 06/07/2020] [Accepted: 06/13/2020] [Indexed: 12/17/2022]
Abstract
Diplonemids are a group of highly diverse and abundant marine microeukaryotes that belong to the phylum Euglenozoa and form a sister clade to the well-studied, mostly parasitic kinetoplastids. Very little is known about the biology of diplonemids, as few species have been formally described and just one, Diplonema papillatum, has been studied to a decent extent at the molecular level. Following up on our previous results showing stable but random integration of delivered extraneous DNA, we demonstrate here homologous recombination in D. papillatum. Targeting various constructs to the intended position in the nuclear genome was successful when 5' and 3' homologous regions longer than 1 kbp were used, achieving N-terminal tagging with mCherry and gene replacement of α- and β-tubulins. For more convenient genetic manipulation, we designed a modular plasmid, pDP002, which bears a protein-A tag and used it to generate and express a C-terminally tagged mitoribosomal protein. Lastly, we developed an improved transformation protocol for broader applicability across laboratories. Our robust methodology allows the replacement, integration as well as endogenous tagging of D. papillatum genes, thus opening the door to functional studies in this species and establishing a basic toolkit for reverse genetics of diplonemids in general.
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Affiliation(s)
- Drahomíra Faktorová
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
| | - Binnypreet Kaur
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
| | - Matus Valach
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Lena Graf
- Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic.,Present address: Johannes Kepler University, Linz, Austria
| | - Corinna Benz
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic
| | - Gertraud Burger
- Department of Biochemistry and Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montreal, Canada
| | - Julius Lukeš
- Czech Academy of Sciences, Institute of Parasitology, Biology Centre, Czech Republic.,Faculty of Sciences, University of South Bohemia, Cˇeské Budějovice (Budweis), Czech Republic
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14
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Silva Pereira S, Heap J, Jones AR, Jackson AP. VAPPER: High-throughput variant antigen profiling in African trypanosomes of livestock. Gigascience 2020; 8:5556439. [PMID: 31494667 PMCID: PMC6735694 DOI: 10.1093/gigascience/giz091] [Citation(s) in RCA: 5] [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: 12/03/2018] [Revised: 06/17/2019] [Accepted: 07/09/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Analysing variant antigen gene families on a population scale is a difficult challenge for conventional methods of read mapping and variant calling due to the great variability in sequence, copy number, and genomic loci. In African trypanosomes, hemoparasites of humans and animals, this is complicated by variant antigen repertoires containing hundreds of genes subject to various degrees of sequence recombination. FINDINGS We introduce Variant Antigen Profiler (VAPPER), a tool that allows automated analysis of the variant surface glycoprotein repertoires of the most prevalent livestock African trypanosomes. VAPPER produces variant antigen profiles for any isolate of the veterinary pathogens Trypanosoma congolense and Trypanosoma vivax from genomic and transcriptomic sequencing data and delivers publication-ready figures that show how the queried isolate compares with a database of existing strains. VAPPER is implemented in Python. It can be installed to a local Galaxy instance from the ToolShed (https://toolshed.g2.bx.psu.edu/) or locally on a Linux platform via the command line (https://github.com/PGB-LIV/VAPPER). The documentation, requirements, examples, and test data are provided in the Github repository. CONCLUSION By establishing two different, yet comparable methodologies, our approach is the first to allow large-scale analysis of African trypanosome variant antigens, large multi-copy gene families that are otherwise refractory to high-throughput analysis.
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Affiliation(s)
- Sara Silva Pereira
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park Ic2, 146 Brownlow Hill, Liverpool L3 5RF, UK
- Correspondence addres. Sara Silva Pereira, E-mail:
| | - John Heap
- Computational Biology Facility, University of Liverpool, Liverpool L69 7ZB, UK
| | - Andrew R Jones
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, UK
| | - Andrew P Jackson
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool Science Park Ic2, 146 Brownlow Hill, Liverpool L3 5RF, UK
- Correspondence addres. Andrew P. Jackson, E-mail:
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15
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Magez S, Pinto Torres JE, Obishakin E, Radwanska M. Infections With Extracellular Trypanosomes Require Control by Efficient Innate Immune Mechanisms and Can Result in the Destruction of the Mammalian Humoral Immune System. Front Immunol 2020; 11:382. [PMID: 32218784 PMCID: PMC7078162 DOI: 10.3389/fimmu.2020.00382] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 02/18/2020] [Indexed: 12/17/2022] Open
Abstract
Salivarian trypanosomes are extracellular parasites that affect humans, livestock, and game animals around the world. Through co-evolution with the mammalian immune system, trypanosomes have developed defense mechanisms that allow them to thrive in blood, lymphoid vessels, and tissue environments such as the brain, the fat tissue, and testes. Trypanosomes have developed ways to circumvent antibody-mediated killing and block the activation of the lytic arm of the complement pathway. Hence, this makes the innate immune control of the infection a crucial part of the host-parasite interaction, determining infection susceptibility, and parasitemia control. Indeed, trypanosomes use a combination of several independent mechanisms to avoid clearance by the humoral immune system. First, perpetuated antigenic variation of the surface coat allows to escape antibody-mediated elimination. Secondly, when antibodies bind to the coat, they are efficiently transported toward the endocytosis pathway, where they are removed from the coat proteins. Finally, trypanosomes engage in the active destruction of the mammalian humoral immune response. This provides them with a rescue solution in case antigenic variation does not confer total immunological invisibility. Both antigenic variation and B cell destruction pose significant hurdles for the development of anti-trypanosome vaccine strategies. However, developing total immune escape capacity and unlimited growth capabilities within a mammalian host is not beneficial for any parasite, as it will result in the accelerated death of the host itself. Hence, trypanosomes have acquired a system of quorum sensing that results in density-dependent population growth arrest in order to prevent overpopulating the host. The same system could possibly sense the infection-associated host tissue damage resulting from inflammatory innate immune responses, in which case the quorum sensing serves to prevent excessive immunopathology and as such also promotes host survival. In order to put these concepts together, this review summarizes current knowledge on the interaction between trypanosomes and the mammalian innate immune system, the mechanisms involved in population growth regulation, antigenic variation and the immuno-destructive effect of trypanosomes on the humoral immune system. Vaccine trials and a discussion on the role of innate immune modulation in these trials are discussed at the end.
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Affiliation(s)
- Stefan Magez
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium.,Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium
| | | | - Emmanuel Obishakin
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Biotechnology Division, National Veterinary Research Institute, Vom, Nigeria
| | - Magdalena Radwanska
- Laboratory for Biomedical Research, Ghent University Global Campus, Incheon, South Korea.,Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
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16
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Mulindwa J, Matovu E, Enyaru J, Clayton C. Blood signatures for second stage human African trypanosomiasis: a transcriptomic approach. BMC Med Genomics 2020; 13:14. [PMID: 32000760 PMCID: PMC6993467 DOI: 10.1186/s12920-020-0666-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 01/20/2020] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Rhodesiense sleeping sickness is caused by infection with T. b rhodesiense parasites resulting in an acute disease that is fatal if not treated in time. The aim of this study was to understand the global impact of active T. b rhodesiense infection on the patient's immune response in the early and late stages of the disease. METHODS RNASeq was carried out on blood and cerebral spinal fluid (CSF) samples obtained from T. b. rhodesiense infected patients. The control samples used were from healthy individuals in the same foci. The Illumina sequenced reads were analysed using the Tuxedo suite pipeline (Tophat, Cufflinks, Cuffmerge, Cuffdiff) and differential expression analysis carried out using the R package DESeq2. The gene enrichment and function annotation analysis were done using the ToppCluster, DAVID and InnateDB algorithms. RESULTS We previously described the transcriptomes of T. b rhodesiense from infected early stage blood (n = 3) and late stage CSF (n = 3) samples from Eastern Uganda. We here identify human transcripts that were differentially expressed (padj < 0.05) in the early stage blood versus healthy controls (n = 3) and early stage blood versus late stage CSF. Differential expression in infected blood showed an enrichment of innate immune response genes whereas that of the CSF showed enrichment for anti-inflammatory and neuro-degeneration signalling pathways. We also identified genes (C1QC, MARCO, IGHD3-10) that were up-regulated (log2 FC > 2.5) in both the blood and CSF. CONCLUSION The data yields insights into the host's response to T. b rhodesiense parasites in the blood and central nervous system. We identified key pathways and signalling molecules for the predominant innate immune response in the early stage infection; and anti-inflammatory and neuro-degeneration pathways associated with sleep disorders in second stage infection. We further identified potential blood biomarkers that can be used for diagnosis of late stage disease without the need for lumbar puncture.
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Affiliation(s)
- Julius Mulindwa
- Department of Biochemistry and Sports Sciences, College of Natural Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda.
| | - Enock Matovu
- Department of Biotechnical and Diagnostic Sciences, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - John Enyaru
- Department of Biochemistry and Sports Sciences, College of Natural Sciences, Makerere University, P. O. Box 7062, Kampala, Uganda
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120, Heidelberg, Germany
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17
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Variable Surface Glycoprotein from Trypanosoma brucei Undergoes Cleavage by Matrix Metalloproteinases: An in silico Approach. Pathogens 2019; 8:pathogens8040178. [PMID: 31597256 PMCID: PMC6963732 DOI: 10.3390/pathogens8040178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 09/24/2019] [Accepted: 09/25/2019] [Indexed: 12/13/2022] Open
Abstract
In order to survive as extracellular parasites in the mammalian host environment, Trypanosoma brucei has developed efficient mechanisms of immune system evasion, which include the abundant expression of a variable surface glycoprotein (VSG) coat. VSGs are anchored in the parasite membrane by covalent C-terminal binding to glycosylphosphatidylinositol and may be periodically removed by a phospholipase C (PLC) and a major surface protein (TbMSP). VSG molecules show extraordinary antigenic diversity and a comparative analysis of protein sequences suggests that conserved elements may be a suitable target against African trypanosomiasis. However, the cleavage mechanisms of these molecules remain unclear. Moreover, in protozoan infections, including those caused by Trypanosoma brucei, it is possible to observe an increased expression of the matrix metalloproteinases (MMPs). To address the cleavage mechanism of VSGs, the PROSPER server was used for the identification of VSG sequence cleavage sites. After data compilation, it was observed that 64 VSG consensus sequences showed a high conservation of hydrophobic residues, such as valine (V), methionine (M), leucine (L) and isoleucine (I) in the fifth position—the exact location of the cleavage site. In addition, the PROSPER server identified conserved cleavage site portions of VSG proteins recognized by three matrix metalloproteases (gelatinases: MMP-2, MMP-3 and MMP-9). However, further biological studies are needed in order to analyze and confirm this prediction.
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18
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Aksoy S. Tsetse peritrophic matrix influences for trypanosome transmission. JOURNAL OF INSECT PHYSIOLOGY 2019; 118:103919. [PMID: 31425686 PMCID: PMC6853167 DOI: 10.1016/j.jinsphys.2019.103919] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Tsetse flies are important vectors of parasitic African trypanosomes, agents of human and animal trypanosomiasis. Easily administrable and effective tools for disease control in the mammalian host are still lacking but reduction of the tsetse vector populations can reduce disease. An alternative approach is to reduce the transmission of trypanosomes in the tsetse vector. The gut peritrophic matrix (PM) has emerged as an important regulator of parasite transmission success in tsetse. Tsetse has a Type II PM that is constitutively produced by cells in the cardia organ. Tsetse PM lines the entire gut and functions as an immunological barrier to prevent the gut epithelia from responding to commensal environmental microbes present in the gut lumen. Tsetse PM also functions as a physical barrier to trypanosome infections that enter into the gut lumen in an infective blood meal. For persistence in the gut, African trypanosomes have developed an adaptive manipulative process to transiently reduce PM efficacy. The process is mediated by mammalian trypanosome surface coat proteins, Variant Surface Glycoproteins (VSGs) which are shed in the gut lumen and taken up by cardia cells. The mechanism of PM reduction involves a tsetse microRNA (miR-275) which acts thru the Wnt signaling pathway. The PM efficacy is once again reduced later in the infection process to enable the gut established parasites to reenter into the gut lumen to colonize the salivary glands, an essential process for transmission. The ability to modulate PM integrity can lead to innovative approaches to reduce disease transmission.
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Affiliation(s)
- Serap Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, 60 College St, LEPH 624, New Haven, CT 06520, United States.
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19
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Terrao M, Marucha KK, Mugo E, Droll D, Minia I, Egler F, Braun J, Clayton C. The suppressive cap-binding complex factor 4EIP is required for normal differentiation. Nucleic Acids Res 2019; 46:8993-9010. [PMID: 30124912 PMCID: PMC6158607 DOI: 10.1093/nar/gky733] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 08/01/2018] [Indexed: 12/27/2022] Open
Abstract
Trypanosoma brucei live in mammals as bloodstream forms and in the Tsetse midgut as procyclic forms. Differentiation from one form to the other proceeds via a growth-arrested stumpy form with low messenger RNA (mRNA) content and translation. The parasites have six eIF4Es and five eIF4Gs. EIF4E1 pairs with the mRNA-binding protein 4EIP but not with any EIF4G. EIF4E1 and 4EIP each inhibit expression when tethered to a reporter mRNA, but while tethered EIF4E1 suppresses only when 4EIP is present, suppression by tethered 4EIP does not require the interaction with EIF4E1. In growing bloodstream forms, 4EIP is preferentially associated with unstable mRNAs. Bloodstream- or procyclic-form trypanosomes lacking 4EIP have only a marginal growth disadvantage. Bloodstream forms without 4EIP are, however, defective in translation suppression during stumpy-form differentiation and cannot subsequently convert to growing procyclic forms. Intriguingly, the differentiation defect can be complemented by a truncated 4EIP that does not interact with EIF4E1. In contrast, bloodstream forms lacking EIF4E1 have a growth defect, stumpy formation seems normal, but they appear unable to grow as procyclic forms. We suggest that 4EIP and EIF4E1 fine-tune mRNA levels in growing cells, and that 4EIP contributes to translation suppression during differentiation to the stumpy form.
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Affiliation(s)
- Monica Terrao
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Kevin K Marucha
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Elisha Mugo
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Dorothea Droll
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Igor Minia
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Johanna Braun
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany
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20
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da Silva MS, Hovel-Miner GA, Briggs EM, Elias MC, McCulloch R. Evaluation of mechanisms that may generate DNA lesions triggering antigenic variation in African trypanosomes. PLoS Pathog 2018; 14:e1007321. [PMID: 30440029 PMCID: PMC6237402 DOI: 10.1371/journal.ppat.1007321] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Antigenic variation by variant surface glycoprotein (VSG) coat switching in African trypanosomes is one of the most elaborate immune evasion strategies found among pathogens. Changes in the identity of the transcribed VSG gene, which is always flanked by 70-bp and telomeric repeats, can be achieved either by transcriptional or DNA recombination mechanisms. The major route of VSG switching is DNA recombination, which occurs in the bloodstream VSG expression site (ES), a multigenic site transcribed by RNA polymerase I. Recombinogenic VSG switching is frequently catalyzed by homologous recombination (HR), a reaction normally triggered by DNA breaks. However, a clear understanding of how such breaks arise-including whether there is a dedicated and ES-focused mechanism-is lacking. Here, we synthesize data emerging from recent studies that have proposed a range of mechanisms that could generate these breaks: action of a nuclease or nucleases; repetitive DNA, most notably the 70-bp repeats, providing an intra-ES source of instability; DNA breaks derived from the VSG-adjacent telomere; DNA breaks arising from high transcription levels at the active ES; and DNA lesions arising from replication-transcription conflicts in the ES. We discuss the evidence that underpins these switch-initiation models and consider what features and mechanisms might be shared or might allow the models to be tested further. Evaluation of all these models highlights that we still have much to learn about the earliest acting step in VSG switching, which may have the greatest potential for therapeutic intervention in order to undermine the key reaction used by trypanosomes for their survival and propagation in the mammalian host.
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Affiliation(s)
- Marcelo Santos da Silva
- Laboratório Especial de Ciclo Celular, Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Galadriel A. Hovel-Miner
- The George Washington University, Department of Microbiology Immunology, and Tropical Medicine, Washington, DC, United States of America
| | - Emma M. Briggs
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Maria Carolina Elias
- Laboratório Especial de Ciclo Celular, Center of Toxins, Immune Response and Cell Signaling (CeTICS), Instituto Butantan, São Paulo, Brazil
| | - Richard McCulloch
- The Wellcome Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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21
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Liu D, Albergante L, Newman TJ, Horn D. Faster growth with shorter antigens can explain a VSG hierarchy during African trypanosome infections: a feint attack by parasites. Sci Rep 2018; 8:10922. [PMID: 30026531 PMCID: PMC6053454 DOI: 10.1038/s41598-018-29296-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/09/2018] [Indexed: 11/22/2022] Open
Abstract
The parasitic African trypanosome, Trypanosoma brucei, evades the adaptive host immune response by a process of antigenic variation that involves the clonal switching of variant surface glycoproteins (VSGs). The VSGs that come to dominate in vivo during an infection are not entirely random, but display a hierarchical order. How this arises is not fully understood. Combining available genetic data with mathematical modelling, we report a VSG-length-dependent hierarchical timing of clonal VSG dominance in a mouse model, consistent with an inverse correlation between VSG length and trypanosome growth-rate. Our analyses indicate that, among parasites switching to new VSGs, those expressing shorter VSGs preferentially accumulate to a detectable level that is sufficient to trigger a targeted immune response. This may be due to the increased metabolic cost of producing longer VSGs. Subsequent elimination of faster-growing parasites then allows slower-growing parasites with longer VSGs to accumulate. This interaction between the host and parasite is able to explain the temporal distribution of VSGs observed in vivo. Thus, our findings reveal a length-dependent hierarchy that operates during T. brucei infection. This represents a 'feint attack' diversion tactic utilised by these persistent parasites to out-maneuver the host adaptive immune system.
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Affiliation(s)
- Dianbo Liu
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
- The Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, MA, 02142, USA.
- Computer Science and Artificial Intelligence Lab, Massachusetts Institute of Technology, 32 Vassar St, Cambridge, MA, 02139, USA.
| | - Luca Albergante
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Institut Curie, PLS Research University, Mines Paris Tech, Inserm U900, F-75005, Paris, France
| | - T J Newman
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
- Solaravus, PO Box 29476, Cupar, KY15 9AS, UK
| | - David Horn
- School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.
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22
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Silva Pereira S, Casas-Sánchez A, Haines LR, Ogugo M, Absolomon K, Sanders M, Kemp S, Acosta-Serrano Á, Noyes H, Berriman M, Jackson AP. Variant antigen repertoires in Trypanosoma congolense populations and experimental infections can be profiled from deep sequence data using universal protein motifs. Genome Res 2018; 28:1383-1394. [PMID: 30006414 PMCID: PMC6120623 DOI: 10.1101/gr.234146.118] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 07/12/2018] [Indexed: 11/25/2022]
Abstract
African trypanosomes are vector-borne hemoparasites of humans and animals. In the mammal, parasites evade the immune response through antigenic variation. Periodic switching of the variant surface glycoprotein (VSG) coat covering their cell surface allows sequential expansion of serologically distinct parasite clones. Trypanosome genomes contain many hundreds of VSG genes, subject to rapid changes in nucleotide sequence, copy number, and chromosomal position. Thus, analyzing, or even quantifying, VSG diversity over space and time presents an enormous challenge to conventional techniques. Indeed, previous population genomic studies have overlooked this vital aspect of pathogen biology for lack of analytical tools. Here we present a method for analyzing population-scale VSG diversity in Trypanosoma congolense from deep sequencing data. Previously, we suggested that T. congolense VSGs segregate into defined “phylotypes” that do not recombine. In our data set comprising 41 T. congolense genome sequences from across Africa, these phylotypes are universal and exhaustive. Screening sequence contigs with diagnostic protein motifs accurately quantifies relative phylotype frequencies, providing a metric of VSG diversity, called the “variant antigen profile.” We applied our metric to VSG expression in the tsetse fly, showing that certain, rare VSG phylotypes may be preferentially expressed in infective, metacyclic-stage parasites. Hence, variant antigen profiling accurately and rapidly determines the T. congolense VSG gene and transcript repertoire from sequence data, without need for manual curation or highly contiguous sequences. It offers a tractable approach to measuring VSG diversity across strains and during infections, which is imperative to understanding the host–parasite interaction at population and individual scales.
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Affiliation(s)
- Sara Silva Pereira
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, United Kingdom
| | - Aitor Casas-Sánchez
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Lee R Haines
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Moses Ogugo
- International Livestock Research Institute, Nairobi 00100, Kenya
| | - Kihara Absolomon
- International Livestock Research Institute, Nairobi 00100, Kenya
| | - Mandy Sanders
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, United Kingdom
| | - Steve Kemp
- International Livestock Research Institute, Nairobi 00100, Kenya
| | - Álvaro Acosta-Serrano
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, United Kingdom
| | - Harry Noyes
- Institute of Integrative Biology, University of Liverpool, Liverpool L69 7ZB, United Kingdom
| | - Matthew Berriman
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton CB10 1SA, United Kingdom
| | - Andrew P Jackson
- Department of Infection Biology, Institute of Infection and Global Health, University of Liverpool, Liverpool L3 5RF, United Kingdom
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23
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Pinger J, Nešić D, Ali L, Aresta-Branco F, Lilic M, Chowdhury S, Kim HS, Verdi J, Raper J, Ferguson MAJ, Papavasiliou FN, Stebbins CE. African trypanosomes evade immune clearance by O-glycosylation of the VSG surface coat. Nat Microbiol 2018; 3:932-938. [PMID: 29988048 PMCID: PMC6108419 DOI: 10.1038/s41564-018-0187-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/04/2018] [Indexed: 11/09/2022]
Abstract
The African trypanosome Trypanosoma brucei spp. is a paradigm for antigenic variation, the orchestrated alteration of cell surface molecules to evade host immunity. The parasite elicits robust antibody-mediated immune responses to its variant surface glycoprotein (VSG) coat, but evades immune clearance by repeatedly accessing a large genetic VSG repertoire and 'switching' to antigenically distinct VSGs. This persistent immune evasion has been ascribed exclusively to amino-acid variance on the VSG surface presented by a conserved underlying protein architecture. We establish here that this model does not account for the scope of VSG structural and biochemical diversity. The 1.4-Å-resolution crystal structure of the variant VSG3 manifests divergence in the tertiary fold and oligomeric state. The structure also reveals an O-linked carbohydrate on the top surface of VSG3. Mass spectrometric analysis indicates that this O-glycosylation site is heterogeneously occupied in VSG3 by zero to three hexose residues and is also present in other VSGs. We demonstrate that this O-glycosylation increases parasite virulence by impairing the generation of protective immunity. These data alter the paradigm of antigenic variation by the African trypanosome, expanding VSG variability beyond amino-acid sequence to include surface post-translational modifications with immunomodulatory impact.
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Affiliation(s)
- Jason Pinger
- The Rockefeller University, Laboratory of Lymphocyte Biology, New York, NY, USA
| | - Dragana Nešić
- The Rockefeller University, Laboratory of Structural Microbiology, New York, NY, USA.,The Rockefeller University, Allen and Frances Adler Laboratory of Blood and Vascular Biology, New York, NY, USA
| | - Liaqat Ali
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, UK
| | - Francisco Aresta-Branco
- Division of Immune Diversity, German Cancer Research Center, Heidelberg, Germany.,Division of Structural Biology of Infection and Immunity, German Cancer Research Center, Heidelberg, Germany
| | - Mirjana Lilic
- The Rockefeller University, Laboratory of Structural Microbiology, New York, NY, USA.,The Rockefeller University, Laboratory of Molecular Biophysics, New York, NY, USA
| | - Shanin Chowdhury
- The Rockefeller University, Laboratory of Lymphocyte Biology, New York, NY, USA
| | - Hee-Sook Kim
- The Rockefeller University, Laboratory of Lymphocyte Biology, New York, NY, USA
| | - Joseph Verdi
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA
| | - Jayne Raper
- Department of Biological Sciences, Hunter College, City University of New York, New York, NY, USA
| | - Michael A J Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, UK.
| | - 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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24
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Mulindwa J, Leiss K, Ibberson D, Kamanyi Marucha K, Helbig C, Melo do Nascimento L, Silvester E, Matthews K, Matovu E, Enyaru J, Clayton C. Transcriptomes of Trypanosoma brucei rhodesiense from sleeping sickness patients, rodents and culture: Effects of strain, growth conditions and RNA preparation methods. PLoS Negl Trop Dis 2018; 12:e0006280. [PMID: 29474390 PMCID: PMC5842037 DOI: 10.1371/journal.pntd.0006280] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/07/2018] [Accepted: 01/29/2018] [Indexed: 11/18/2022] Open
Abstract
All of our current knowledge of African trypanosome metabolism is based on results from trypanosomes grown in culture or in rodents. Drugs against sleeping sickness must however treat trypanosomes in humans. We here compare the transcriptomes of Trypanosoma brucei rhodesiense from the blood and cerebrospinal fluid of human patients with those of trypanosomes from culture and rodents. The data were aligned and analysed using new user-friendly applications designed for Kinetoplastid RNA-Seq data. The transcriptomes of trypanosomes from human blood and cerebrospinal fluid did not predict major metabolic differences that might affect drug susceptibility. Usefully, there were relatively few differences between the transcriptomes of trypanosomes from patients and those of similar trypanosomes grown in rats. Transcriptomes of monomorphic laboratory-adapted parasites grown in in vitro culture closely resembled those of the human parasites, but some differences were seen. In poly(A)-selected mRNA transcriptomes, mRNAs encoding some protein kinases and RNA-binding proteins were under-represented relative to mRNA that had not been poly(A) selected; further investigation revealed that the selection tends to result in loss of longer mRNAs.
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Affiliation(s)
- Julius Mulindwa
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
- Department of Biochemistry and Sports Science, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Kevin Leiss
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
| | | | - Kevin Kamanyi Marucha
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
| | - Claudia Helbig
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
| | - Larissa Melo do Nascimento
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
| | - Eleanor Silvester
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Keith Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Enock Matovu
- Department of Biotechnology and Diagnostic Sciences, College of Veterinary medicine, Animal resources and Biosecurity, Makerere University, Kampala, Uganda
| | - John Enyaru
- Department of Biochemistry and Sports Science, College of Natural Sciences, Makerere University, Kampala, Uganda
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, Heidelberg, Germany
- * E-mail:
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25
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The Fantastic Voyage of the Trypanosome: A Protean Micromachine Perfected during 500 Million Years of Engineering. MICROMACHINES 2018; 9:mi9020063. [PMID: 30393339 PMCID: PMC6187515 DOI: 10.3390/mi9020063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 01/30/2018] [Accepted: 02/01/2018] [Indexed: 01/29/2023]
Abstract
The human body is constantly attacked by pathogens. Various lines of defence have evolved, among which the immune system is principal. In contrast to most pathogens, the African trypanosomes thrive freely in the blood circulation, where they escape immune destruction by antigenic variation and incessant motility. These unicellular parasites are flagellate microswimmers that also withstand the harsh mechanical forces prevailing in the bloodstream. They undergo complex developmental cycles in the bloodstream and organs of the mammalian host, as well as the disease-transmitting tsetse fly. Each life cycle stage has been shaped by evolution for manoeuvring in distinct microenvironments. Here, we introduce trypanosomes as blueprints for nature-inspired design of trypanobots, micromachines that, in the future, could explore the human body without affecting its physiology. We review cell biological and biophysical aspects of trypanosome motion. While this could provide a basis for the engineering of microbots, their actuation and control still appear more like fiction than science. Here, we discuss potentials and challenges of trypanosome-inspired microswimmer robots.
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26
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Zhou W, Brisson D. Interactions between host immune response and antigenic variation that control Borrelia burgdorferi population dynamics. MICROBIOLOGY-SGM 2017; 163:1179-1188. [PMID: 28771127 DOI: 10.1099/mic.0.000513] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The population dynamics of pathogens within hosts result from interactions between host immune responses and mechanisms of the pathogen to evade or resist immune responses. Vertebrate hosts have evolved adaptive immune responses to eliminate the infection, while many pathogens evade immune clearance through altering surface antigens. Such interactions can result in a characteristic pattern of pathogen population dynamics within hosts consisting of population growth after infection, rapid population decline following specific immune responses, followed by persistence at low densities during a chronic infection stage. Despite the medical importance of chronic infections, little is known about the conditions of the interactions between variable antigens and the adaptive immune system that cause the characteristic pathogen population dynamics. Using the vls antigenic variation system of the Lyme disease pathogen, Borrelia burgdorferi, as a model system, we investigated conditions of the interaction between the antigenic variation system and the adaptive immune response that can explain the within-host population dynamics of B. burgdorferi using mathematical modelling. This characteristic population dynamic pattern can be explained by models that assume a variable immune removal rate of antibody-bound B. burgdorferi. However, models with a constant immune removal rate could reproduce the rapid population decline of B. burgdorferi populations but not their long-term persistence within hosts using parameter values determined by fitting empirical data. The model predictions, along with the assumptions about the interactions between B. burgdorferi and the immune response, can be tested experimentally to estimate the likelihood that each mechanism affects B. burgdorferi population dynamics in real infections.
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Affiliation(s)
- Wei Zhou
- University of Pennsylvania, 3451 Walnut Street, Philadelphia, PA 19104, USA
| | - Dustin Brisson
- University of Pennsylvania, 3451 Walnut Street, Philadelphia, PA 19104, USA
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27
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RNAi screening identifies Trypanosoma brucei stress response protein kinases required for survival in the mouse. Sci Rep 2017; 7:6156. [PMID: 28733613 PMCID: PMC5522463 DOI: 10.1038/s41598-017-06501-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 05/26/2017] [Indexed: 01/05/2023] Open
Abstract
Protein kinases (PKs) are a class of druggable targets in Trypanosoma brucei, the causative agent of Human African Trypanosomiasis (sleeping sickness), yet little is known about which PKs are essential for survival in mammals. A recent kinome-wide RNAi screen with 176 individual bloodstream form Trypanosoma brucei lines identified PKs required for proliferation in culture. In order to assess which PKs are also potential virulence factors essential in vivo, lines were pooled, inoculated into mice, and screened for loss of fitness after 48 h RNAi. The presence of trypanosomes in the bloodstream was assessed using RNAi target sequencing (RITseq) and compared to growth in culture. We identified 49 PKs with a significant loss of fitness in vivo in two independent experiments, and a strong correlation between in vitro and in vivo loss of fitness for the majority. Nine PKs had a more pronounced growth defect in vivo, than in vitro. Amongst these PKs were several with putative functions related to stress responses mediated through the PI3K/TOR or MAPK signaling cascades, which act to protect the parasite from complement-mediated and osmotic lysis. Identification of these virulence-associated PKs provides new insights into T. brucei-host interaction and reveals novel potential protein kinase drug targets.
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28
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Silvester E, McWilliam KR, Matthews KR. The Cytological Events and Molecular Control of Life Cycle Development of Trypanosoma brucei in the Mammalian Bloodstream. Pathogens 2017; 6:pathogens6030029. [PMID: 28657594 PMCID: PMC5617986 DOI: 10.3390/pathogens6030029] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/21/2017] [Accepted: 06/22/2017] [Indexed: 12/21/2022] Open
Abstract
African trypanosomes cause devastating disease in sub-Saharan Africa in humans and livestock. The parasite lives extracellularly within the bloodstream of mammalian hosts and is transmitted by blood-feeding tsetse flies. In the blood, trypanosomes exhibit two developmental forms: the slender form and the stumpy form. The slender form proliferates in the bloodstream, establishes the parasite numbers and avoids host immunity through antigenic variation. The stumpy form, in contrast, is non-proliferative and is adapted for transmission. Here, we overview the features of slender and stumpy form parasites in terms of their cytological and molecular characteristics and discuss how these contribute to their distinct biological functions. Thereafter, we describe the technical developments that have enabled recent discoveries that uncover how the slender to stumpy transition is enacted in molecular terms. Finally, we highlight new understanding of how control of the balance between slender and stumpy form parasites interfaces with other components of the infection dynamic of trypanosomes in their mammalian hosts. This interplay between the host environment and the parasite’s developmental biology may expose new vulnerabilities to therapeutic attack or reveal where drug control may be thwarted by the biological complexity of the parasite’s lifestyle.
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Affiliation(s)
- Eleanor Silvester
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
| | - Kirsty R McWilliam
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
| | - Keith R Matthews
- Institute for Immunology and Infection Research, Centre for Immunity, Infection and Evolution, School of Biological Sciences, King's Buildings, University of Edinburgh, Charlotte Auerbach Road, Edinburgh EH9 3FL, UK.
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29
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Giardia Colonizes and Encysts in High-Density Foci in the Murine Small Intestine. mSphere 2017; 2:mSphere00343-16. [PMID: 28656177 PMCID: PMC5480036 DOI: 10.1128/msphere.00343-16] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 04/21/2017] [Indexed: 01/28/2023] Open
Abstract
Giardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation. Giardia lamblia is a highly prevalent yet understudied protistan parasite causing significant diarrheal disease worldwide. Hosts ingest Giardia cysts from contaminated sources. In the gastrointestinal tract, cysts excyst to become motile trophozoites, colonizing and attaching to the gut epithelium. Trophozoites later differentiate into infectious cysts that are excreted and contaminate the environment. Due to the limited accessibility of the gut, the temporospatial dynamics of giardiasis in the host are largely inferred from laboratory culture and thus may not mirror Giardia physiology in the host. Here, we have developed bioluminescent imaging (BLI) to directly interrogate and quantify the in vivo temporospatial dynamics of Giardia infection, thereby providing an improved murine model to evaluate anti-Giardia drugs. Using BLI, we determined that parasites primarily colonize the proximal small intestine nonuniformly in high-density foci. By imaging encystation-specific bioreporters, we show that encystation initiates shortly after inoculation and continues throughout the duration of infection. Encystation also initiates in high-density foci in the proximal small intestine, and high density contributes to the initiation of encystation in laboratory culture. We suggest that these high-density in vivo foci of colonizing and encysting Giardia likely result in localized disruption to the epithelium. This more accurate visualization of giardiasis redefines the dynamics of the in vivo Giardia life cycle, paving the way for future mechanistic studies of density-dependent parasitic processes in the host. IMPORTANCEGiardia is a single-celled parasite causing significant diarrheal disease in several hundred million people worldwide. Due to limited access to the site of infection in the gastrointestinal tract, our understanding of the dynamics of Giardia infections in the host has remained limited and largely inferred from laboratory culture. To better understand Giardia physiology and colonization in the host, we developed imaging methods to quantify Giardia expressing bioluminescent physiological reporters in two relevant animal models. We discovered that parasites primarily colonize and encyst in the proximal small intestine in discrete, high-density foci. We also show that high parasite density contributes to encystation initiation.
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30
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Devlin R, Marques CA, McCulloch R. Does DNA replication direct locus-specific recombination during host immune evasion by antigenic variation in the African trypanosome? Curr Genet 2017; 63:441-449. [PMID: 27822899 PMCID: PMC5422504 DOI: 10.1007/s00294-016-0662-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 10/26/2016] [Accepted: 10/27/2016] [Indexed: 12/14/2022]
Abstract
All pathogens must survive host immune attack and, amongst the survival strategies that have evolved, antigenic variation is a particularly widespread reaction to thwart adaptive immunity. Though the reactions that underlie antigenic variation are highly varied, recombination by gene conversion is a widespread approach to immune survival in bacterial and eukaryotic pathogens. In the African trypanosome, antigenic variation involves gene conversion-catalysed movement of a huge number of variant surface glycoprotein (VSG) genes into a few telomeric sites for VSG expression, amongst which only a single site is actively transcribed at one time. Genetic evidence indicates VSG gene conversion has co-opted the general genome maintenance reaction of homologous recombination, aligning the reaction strategy with targeted rearrangements found in many organisms. What is less clear is how gene conversion might be initiated within the locality of the VSG expression sites. Here, we discuss three emerging models for VSG switching initiation and ask how these compare with processes for adaptive genome change found in other organisms.
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Affiliation(s)
- Rebecca Devlin
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
| | - Catarina A Marques
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK
- Division of Biological Chemistry and Drug Discovery, College of Life Sciences, University of Dundee, Dundee, UK
| | - Richard McCulloch
- The Wellcome Trust Centre for Molecular Parasitology, Institute of Infection, Immunity and Inflammation, University of Glasgow, Sir Graeme Davis Building, 120 University Place, Glasgow, G12 8TA, UK.
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31
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Rico E, Ivens A, Glover L, Horn D, Matthews KR. Genome-wide RNAi selection identifies a regulator of transmission stage-enriched gene families and cell-type differentiation in Trypanosoma brucei. PLoS Pathog 2017; 13:e1006279. [PMID: 28334017 PMCID: PMC5380359 DOI: 10.1371/journal.ppat.1006279] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 04/04/2017] [Accepted: 03/08/2017] [Indexed: 01/07/2023] Open
Abstract
Trypanosoma brucei, causing African sleeping-sickness, exploits quorum-sensing (QS) to generate the ‘stumpy forms’ necessary for the parasite’s transmission to tsetse-flies. These quiescent cells are generated by differentiation in the bloodstream from proliferative slender forms. Using genome-wide RNAi selection we screened for repressors of transmission stage-enriched mRNAs in slender forms, using the stumpy-elevated ESAG9 transcript as a model. This identified REG9.1, whose RNAi-silencing alleviated ESAG9 repression in slender forms and tsetse-midgut procyclic forms. Interestingly, trypanosome surface protein Family 5 and Family 7 mRNAs were also elevated, which, like ESAG9, are T. brucei specific and stumpy-enriched. We suggest these contribute to the distinct transmission biology and vector tropism of T. brucei from other African trypanosome species. As well as surface family regulation, REG9.1-depletion generated QS-independent development to stumpy forms in vivo, whereas REG9.1 overexpression in bloodstream forms potentiated spontaneous differentiation to procyclic forms in the absence of an external signal. Combined, this identifies REG9.1 as a regulator of developmental cell fate, controlling the expression of Trypanosoma brucei-specific molecules elevated during transmission. African trypanosomes cause important disease of humans and livestock in sub Saharan Africa and are transmitted by tsetse flies. In preparation for transmission, Trypanosoma brucei uses quorum sensing to generate ‘stumpy forms’ that are arrested and express a distinct subset of genes to the ‘slender forms’ that proliferate to establish the parasitaemia in the bloodstream. This necessitates that stumpy-enriched transcripts are repressed in slender forms, although the molecular control of this is unknown. Here, we have developed a genome-wide selectional strategy to isolate repressors of stumpy-enriched genes, and successfully identified a novel regulatory molecule, termed REG9.1. Silencing of REG9.1 alleviates the repression of the previously characterised stumpy-enriched ESAG9 gene family, and also two novel predicted surface protein families that are specific to Trypansoma brucei but absent from other African trypanosome species. REG9.1 silencing also drives density-independent differentiation to stumpy forms, whereas its ectopic expression in bloodstream forms potentiates differentiation to tsetse midgut procyclic forms in the absence of an external signal. REG9.1 is therefore identified as a novel developmental regulator whose action may contribute to the species-specific transmission biology of Trypanosoma brucei, which differs from that of either Trypanosoma congolense or Trypanosoma vivax.
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Affiliation(s)
- Eva Rico
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Alasdair Ivens
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Lucy Glover
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - David Horn
- The Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, Scotland, United Kingdom
| | - Keith R. Matthews
- Centre for Immunity, Infection and Evolution, Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- * E-mail:
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Ponte-Sucre A. An Overview of Trypanosoma brucei Infections: An Intense Host-Parasite Interaction. Front Microbiol 2016; 7:2126. [PMID: 28082973 PMCID: PMC5183608 DOI: 10.3389/fmicb.2016.02126] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Accepted: 12/16/2016] [Indexed: 12/14/2022] Open
Abstract
Trypanosoma brucei rhodesiense and T. brucei gambiense, the causative agents of Human African Trypanosomiasis, are transmitted by tsetse flies. Within the vector, the parasite undergoes through transformations that prepares it to infect the human host. Sequentially these developmental stages are the replicative procyclic (in which the parasite surface is covered by procyclins) and trypo-epimastigote forms, as well as the non-replicative, infective, metacyclic form that develops in the vector salivary glands. As a pre-adaptation to their life in humans, metacyclic parasites begin to express and be densely covered by the Variant Surface Glycoprotein (VSG). Once the metacyclic form invades the human host the parasite develops into the bloodstream form. Herein the VSG triggers a humoral immune response. To avoid this humoral response, and essential for survival while in the bloodstream, the parasite changes its cover periodically and sheds into the surroundings the expressed VSG, thus evading the consequences of the immune system activation. Additionally, tools comparable to quorum sensing are used by the parasite for the successful parasite transmission from human to insect. On the other hand, the human host promotes clearance of the parasite triggering innate and adaptive immune responses and stimulating cytokine and chemokine secretion. All in all, the host–parasite interaction is extremely active and leads to responses that need multiple control sites to develop appropriately.
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Affiliation(s)
- Alicia Ponte-Sucre
- Laboratory of Molecular Physiology, Institute of Experimental Medicine, Luis Razetti School of Medicine, Faculty of Medicine, Universidad Central de Venezuela Caracas, Venezuela
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Minia I, Merce C, Terrao M, Clayton C. Translation Regulation and RNA Granule Formation after Heat Shock of Procyclic Form Trypanosoma brucei: Many Heat-Induced mRNAs Are also Increased during Differentiation to Mammalian-Infective Forms. PLoS Negl Trop Dis 2016; 10:e0004982. [PMID: 27606618 PMCID: PMC5015846 DOI: 10.1371/journal.pntd.0004982] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/16/2016] [Indexed: 11/18/2022] Open
Abstract
African trypanosome procyclic forms multiply in the midgut of tsetse flies, and are routinely cultured at 27°C. Heat shocks of 37°C and above result in general inhibition of translation, and severe heat shock (41°C) results in sequestration of mRNA in granules. The mRNAs that are bound by the zinc-finger protein ZC3H11, including those encoding refolding chaperones, escape heat-induced translation inhibition. At 27°C, ZC3H11 mRNA is predominantly present as an untranslated cytosolic messenger ribonucleoprotein particle, but after heat shocks of 37°C—41°C, the ZC3H11 mRNA moves into the polysomal fraction. To investigate the scope and specificities of heat-shock translational regulation and granule formation, we analysed the distributions of mRNAs on polysomes at 27°C and after 1 hour at 39°C, and the mRNA content of 41°C heat shock granules. We found that mRNAs that bind to ZC3H11 remained in polysomes at 39°C and were protected from sequestration in granules at 41°C. As previously seen for starvation stress granules, the mRNAs that encode ribosomal proteins were excluded from heat-shock granules. 70 mRNAs moved towards the polysomal fraction after the 39°C heat shock, and 260 increased in relative abundance. Surprisingly, many of these mRNAs are also increased when trypanosomes migrate to the tsetse salivary glands. It therefore seems possible that in the wild, temperature changes due to diurnal variations and periodic intake of warm blood might influence the efficiency with which procyclic forms develop into mammalian-infective forms. When trypanosomes are inside tsetse flies, they have to cope with temperature variations from below 20°C up to 37°C, due to diurnal variations and periodic intake of warm blood. In the laboratory, procyclic forms (the form that multiplies in the midgut), are routinely cultured at 27°C. When procyclic forms are heated to temperatures of 37°C and above, they decrease protein production, and at 41°C, mRNAs aggregate into granules. We show here that quite a large number of mRNAs are not included in granules and continue to be used for making proteins. Some of the proteins that continue to be made are needed in order to defend the cells against the effects of heat shock. Interestingly, however, a moderate heat shock stimulates expression of genes needed for the parasites to develop further into forms that can colonise the salivary glands. It thus seems possible that in the field, temperature variations might influence the efficiency with which of trypanosomes in tsetse flies become infective for mammals.
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Affiliation(s)
- Igor Minia
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Clementine Merce
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Monica Terrao
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Christine Clayton
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
- * E-mail:
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34
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Jackson AP. Gene family phylogeny and the evolution of parasite cell surfaces. Mol Biochem Parasitol 2016; 209:64-75. [DOI: 10.1016/j.molbiopara.2016.03.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/18/2016] [Accepted: 03/19/2016] [Indexed: 11/30/2022]
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Morrison LJ, Vezza L, Rowan T, Hope JC. Animal African Trypanosomiasis: Time to Increase Focus on Clinically Relevant Parasite and Host Species. Trends Parasitol 2016; 32:599-607. [PMID: 27167665 DOI: 10.1016/j.pt.2016.04.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 04/19/2016] [Accepted: 04/20/2016] [Indexed: 10/21/2022]
Abstract
Animal African trypanosomiasis (AAT), caused by Trypanosoma congolense and Trypanosoma vivax, remains one of the most important livestock diseases in sub-Saharan Africa, particularly affecting cattle. Despite this, our detailed knowledge largely stems from the human pathogen Trypanosoma brucei and mouse experimental models. In the postgenomic era, the genotypic and phenotypic differences between the AAT-relevant species of parasite or host and their model organism counterparts are increasingly apparent. Here, we outline the timeliness and advantages of increasing the research focus on both the clinically relevant parasite and host species, given that improved tools and resources for both have been developed in recent years. We propose that this shift of emphasis will improve our ability to efficiently develop tools to combat AAT.
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Affiliation(s)
- Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK.
| | - Laura Vezza
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Tim Rowan
- GALVmed, Doherty Building, Pentlands Science Park, Bush Loan, Edinburgh, EH25 0PZ, UK
| | - Jayne C Hope
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
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Stijlemans B, Caljon G, Van Den Abbeele J, Van Ginderachter JA, Magez S, De Trez C. Immune Evasion Strategies of Trypanosoma brucei within the Mammalian Host: Progression to Pathogenicity. Front Immunol 2016; 7:233. [PMID: 27446070 PMCID: PMC4919330 DOI: 10.3389/fimmu.2016.00233] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/30/2016] [Indexed: 12/26/2022] Open
Abstract
The diseases caused by African trypanosomes (AT) are of both medical and veterinary importance and have adversely influenced the economic development of sub-Saharan Africa. Moreover, so far not a single field applicable vaccine exists, and chemotherapy is the only strategy available to treat the disease. These strictly extracellular protozoan parasites are confronted with different arms of the host's immune response (cellular as well as humoral) and via an elaborate and efficient (vector)-parasite-host interplay they have evolved efficient immune escape mechanisms to evade/manipulate the entire host immune response. This is of importance, since these parasites need to survive sufficiently long in their mammalian/vector host in order to complete their life cycle/transmission. Here, we will give an overview of the different mechanisms AT (i.e. T. brucei as a model organism) employ, comprising both tsetse fly saliva and parasite-derived components to modulate host innate immune responses thereby sculpturing an environment that allows survival and development within the mammalian host.
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Affiliation(s)
- Benoît Stijlemans
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Guy Caljon
- Laboratory for Microbiology, Parasitology and Hygiene (LMPH), University of Antwerp, Wilrijk, Belgium; Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM), Antwerp, Belgium
| | - Jan Van Den Abbeele
- Unit of Veterinary Protozoology, Department of Biomedical Sciences, Institute of Tropical Medicine Antwerp (ITM) , Antwerp , Belgium
| | - Jo A Van Ginderachter
- Laboratory of Myeloid Cell Immunology, VIB Inflammation Research Center, Ghent, Belgium; Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
| | - Carl De Trez
- Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel (VUB), Brussels, Belgium; Department of Structural Biology, VIB, Brussels, Belgium
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Aksoy E, Vigneron A, Bing X, Zhao X, O'Neill M, Wu YN, Bangs JD, Weiss BL, Aksoy S. Mammalian African trypanosome VSG coat enhances tsetse's vector competence. Proc Natl Acad Sci U S A 2016; 113:6961-6. [PMID: 27185908 PMCID: PMC4922192 DOI: 10.1073/pnas.1600304113] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Tsetse flies are biological vectors of African trypanosomes, the protozoan parasites responsible for causing human and animal trypanosomiases across sub-Saharan Africa. Currently, no vaccines are available for disease prevention due to antigenic variation of the Variant Surface Glycoproteins (VSG) that coat parasites while they reside within mammalian hosts. As a result, interference with parasite development in the tsetse vector is being explored to reduce disease transmission. A major bottleneck to infection occurs as parasites attempt to colonize tsetse's midgut. One critical factor influencing this bottleneck is the fly's peritrophic matrix (PM), a semipermeable, chitinous barrier that lines the midgut. The mechanisms that enable trypanosomes to cross this barrier are currently unknown. Here, we determined that as parasites enter the tsetse's gut, VSG molecules released from trypanosomes are internalized by cells of the cardia-the tissue responsible for producing the PM. VSG internalization results in decreased expression of a tsetse microRNA (mir-275) and interferes with the Wnt-signaling pathway and the Iroquois/IRX transcription factor family. This interference reduces the function of the PM barrier and promotes parasite colonization of the gut early in the infection process. Manipulation of the insect midgut homeostasis by the mammalian parasite coat proteins is a novel function and indicates that VSG serves a dual role in trypanosome biology-that of facilitating transmission through its mammalian host and insect vector. We detail critical steps in the course of trypanosome infection establishment that can serve as novel targets to reduce the tsetse's vector competence and disease transmission.
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Affiliation(s)
- Emre Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - Aurélien Vigneron
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - XiaoLi Bing
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - Xin Zhao
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - Michelle O'Neill
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - Yi-Neng Wu
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520
| | - James D Bangs
- Department of Microbiology and Immunology, University at Buffalo (SUNY), Buffalo, NY 14214
| | - Brian L Weiss
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520;
| | - Serap Aksoy
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT 06520;
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Superinfection Exclusion of the Ruminant Pathogen Anaplasma marginale in Its Tick Vector Is Dependent on the Time between Exposures to the Strains. Appl Environ Microbiol 2016; 82:3217-3224. [PMID: 26994084 PMCID: PMC4959236 DOI: 10.1128/aem.00190-16] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/15/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The remarkable genetic diversity of vector-borne pathogens allows for the establishment of superinfection in the mammalian host. To have a long-term impact on population strain structure, the introduced strains must also be transmitted by a vector population that has been exposed to the existing primary strain. The sequential exposure of the vector to multiple strains frequently prevents establishment of the second strain, a phenomenon termed superinfection exclusion. As a consequence, superinfection exclusion may greatly limit genetic diversity in the host population, which is difficult to reconcile with the high degree of genetic diversity maintained among vector-borne pathogens. Using Anaplasma marginale, a tick-borne bacterial pathogen of ruminants, we hypothesized that superinfection exclusion is temporally dependent and that longer intervals between strain exposures allow successful acquisition and transmission of a superinfecting strain. To test this hypothesis, we sequentially exposed Dermacentor andersoni ticks to two readily tick-transmissible strains of A. marginale The tick feedings were either immediately sequential or 28 days apart. Ticks were allowed to transmission feed and were individually assessed to determine if they were infected with one or both strains. The second strain was excluded from the tick when the exposure interval was brief but not when it was prolonged. Midguts and salivary glands of individual ticks were superinfected and transmission of both strains occurred only when the exposure interval was prolonged. These findings indicate that superinfection exclusion is temporally dependent, which helps to account for the differences in pathogen strain structure in tropical compared to temperate regions. IMPORTANCE Many vector-borne pathogens have marked genetic diversity, which influences pathogen traits such as transmissibility and virulence. The most successful strains are those that are preferentially transmitted by the vector. However, the factors that determine successful transmission of a particular strain are unknown. In the case of intracellular, bacterial, tick-borne pathogens, one potential factor is superinfection exclusion, in which colonization of ticks by the first strain of a pathogen it encounters prevents the transmission of a second strain. Using A. marginale, the most prevalent tick-borne pathogen of cattle worldwide, and its natural tick vector, we determined that superinfection exclusion occurs when the time between exposures to two strains is brief but not when it is prolonged. These findings suggest that superinfection exclusion may influence strain transmission in temperate regions, where tick activity is limited by season, but not in tropical regions, where ticks are active for long periods.
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Yaro M, Munyard KA, Stear MJ, Groth DM. Combatting African Animal Trypanosomiasis (AAT) in livestock: The potential role of trypanotolerance. Vet Parasitol 2016; 225:43-52. [PMID: 27369574 DOI: 10.1016/j.vetpar.2016.05.003] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 04/29/2016] [Accepted: 05/01/2016] [Indexed: 01/09/2023]
Abstract
African Animal Trypanosomiasis (AAT) is endemic in at least 37 of the 54 countries in Africa. It is estimated to cause direct and indirect losses to the livestock production industry in excess of US$ 4.5 billion per annum. A century of intervention has yielded limited success, owing largely to the extraordinary complexity of the host-parasite interaction. Trypanotolerance, which refers to the inherent ability of some African livestock breeds, notably Djallonke sheep, N'Dama cattle and West African Dwarf goats, to withstand a trypanosomiasis challenge and still remain productive without any form of therapy, is an economically sustainable option for combatting this disease. Yet trypanotolerance has not been adequately exploited in the fight against AAT. In this review, we describe new insights into the genetic basis of trypanotolerance and discuss the potential of exploring this phenomenon as an integral part of the solution for AAT, particularly, in the context of African animal production systems.
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Affiliation(s)
- M Yaro
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
| | - K A Munyard
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
| | - M J Stear
- Institute of Biodiversity, Animal Health and Comparative Medicine, Glasgow University, Garscube Estate, Bearsden Road, Glasgow G61 1QH, UK
| | - D M Groth
- School of Biomedical Sciences, Curtin Health Innovation Research Institute, Faculty of Health Sciences, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
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40
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Restif O, Graham AL. Within-host dynamics of infection: from ecological insights to evolutionary predictions. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2014.0304. [PMID: 26150670 PMCID: PMC4528502 DOI: 10.1098/rstb.2014.0304] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Affiliation(s)
- Olivier Restif
- Disease Dynamics Unit, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Andrea L Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
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Perdomo D, Bonhivers M, Robinson DR. The Trypanosome Flagellar Pocket Collar and Its Ring Forming Protein-TbBILBO1. Cells 2016; 5:cells5010009. [PMID: 26950156 PMCID: PMC4810094 DOI: 10.3390/cells5010009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 12/11/2022] Open
Abstract
Sub-species of Trypanosoma brucei are the causal agents of human African sleeping sickness and Nagana in domesticated livestock. These pathogens have developed an organelle-like compartment called the flagellar pocket (FP). The FP carries out endo- and exocytosis and is the only structure this parasite has evolved to do so. The FP is essential for parasite viability, making it an interesting structure to evaluate as a drug target, especially since it has an indispensible cytoskeleton component called the flagellar pocket collar (FPC). The FPC is located at the neck of the FP where the flagellum exits the cell. The FPC has a complex architecture and division cycle, but little is known concerning its organization. Recent work has focused on understanding how the FP and the FPC are formed and as a result of these studies an important calcium-binding, polymer-forming protein named TbBILBO1 was identified. Cellular biology analysis of TbBILBO1 has demonstrated its uniqueness as a FPC component and until recently, it was unknown what structural role it played in forming the FPC. This review summarizes the recent data on the polymer forming properties of TbBILBO1 and how these are correlated to the FP cytoskeleton.
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Affiliation(s)
- Doranda Perdomo
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
| | - Mélanie Bonhivers
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
| | - Derrick R Robinson
- CNRS, Microbiology Fundamental and Pathogenicity, UMR 5234, F-33000 Bordeaux, France.
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Krüger T, Engstler M. Flagellar motility in eukaryotic human parasites. Semin Cell Dev Biol 2015; 46:113-27. [DOI: 10.1016/j.semcdb.2015.10.034] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/26/2015] [Accepted: 10/26/2015] [Indexed: 12/31/2022]
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