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Banerjee S, Minshall N, Webb H, Carrington M. How are Trypanosoma brucei receptors protected from host antibody-mediated attack? Bioessays 2024; 46:e2400053. [PMID: 38713161 DOI: 10.1002/bies.202400053] [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: 03/11/2024] [Revised: 04/11/2024] [Accepted: 04/15/2024] [Indexed: 05/08/2024]
Abstract
Trypanosoma brucei is the causal agent of African Trypanosomiasis in humans and other animals. It maintains a long-term infection through an antigenic variation based population survival strategy. To proliferate in a mammal, T. brucei acquires iron and haem through the receptor mediated uptake of host transferrin and haptoglobin-hemoglobin respectively. The receptors are exposed to host antibodies but this does not lead to clearance of the infection. Here we discuss how the trypanosome avoids this fate in the context of recent findings on the structure and cell biology of the receptors.
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Affiliation(s)
- Sourav Banerjee
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Nicola Minshall
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Helena Webb
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, UK
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Duncan SM, Carbajo CG, Nagar R, Zhong Q, Breen C, Ferguson MAJ, Tiengwe C. Generation of a bloodstream form Trypanosoma brucei double glycosyltransferase null mutant competent in receptor-mediated endocytosis of transferrin. PLoS Pathog 2024; 20:e1012333. [PMID: 38935804 PMCID: PMC11236118 DOI: 10.1371/journal.ppat.1012333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2024] [Revised: 07/10/2024] [Accepted: 06/10/2024] [Indexed: 06/29/2024] Open
Abstract
The bloodstream form of Trypanosoma brucei expresses large poly-N-acetyllactosamine (pNAL) chains on complex N-glycans of a subset of glycoproteins. It has been hypothesised that pNAL may be required for receptor-mediated endocytosis. African trypanosomes contain a unique family of glycosyltransferases, the GT67 family. Two of these, TbGT10 and TbGT8, have been shown to be involved in pNAL biosynthesis in bloodstream form Trypanosoma brucei, raising the possibility that deleting both enzymes simultaneously might abolish pNAL biosynthesis and provide clues to pNAL function and/or essentiality. In this paper, we describe the creation of a TbGT10 null mutant containing a single TbGT8 allele that can be excised upon the addition of rapamycin and, from that, a TbGT10 and TbGT8 double null mutant. These mutants were analysed by lectin blotting, glycopeptide methylation linkage analysis and flow cytometry. The data show that the mutants are defective, but not abrogated, in pNAL synthesis, suggesting that other GT67 family members can compensate to some degree for loss of TbGT10 and TbGT8. Despite there being residual pNAL synthesis in these mutants, certain glycoproteins appear to be particularly affected. These include the lysosomal CBP1B serine carboxypeptidase, cell surface ESAG2 and the ESAG6 subunit of the essential parasite transferrin receptor (TfR). The pNAL deficient TfR in the mutants continued to function normally with respect to protein stability, transferrin binding, receptor mediated endocytosis of transferrin and subcellular localisation. Further the pNAL deficient mutants were as viable as wild type parasites in vitro and in in vivo mouse infection experiments. Although we were able to reproduce the inhibition of transferrin uptake with high concentrations of pNAL structural analogues (N-acetylchito-oligosaccharides), this effect disappeared at lower concentrations that still inhibited tomato lectin uptake, i.e., at concentrations able to outcompete lectin-pNAL binding. Based on these findings, we recommend revision of the pNAL-dependent receptor mediated endocytosis hypothesis.
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Affiliation(s)
- Samuel M. Duncan
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Carla Gilabert Carbajo
- Faculty of Natural Sciences, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Rupa Nagar
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Qi Zhong
- Faculty of Natural Sciences, Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Conor Breen
- Regeneron Biotech, Raheen Business Park, Limerick, Ireland
| | - Michael A. J. Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Calvin Tiengwe
- Faculty of Natural Sciences, Department of Life Sciences, Imperial College London, London, United Kingdom
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Kariuki CK, Stijlemans B, Magez S. The Trypanosomal Transferrin Receptor of Trypanosoma Brucei-A Review. Trop Med Infect Dis 2019; 4:tropicalmed4040126. [PMID: 31581506 PMCID: PMC6958415 DOI: 10.3390/tropicalmed4040126] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 02/06/2023] Open
Abstract
Iron is an essential element for life. Its uptake and utility requires a careful balancing with its toxic capacity, with mammals evolving a safe and bio-viable means of its transport and storage. This transport and storage is also utilized as part of the iron-sequestration arsenal employed by the mammalian hosts’ ‘nutritional immunity’ against parasites. Interestingly, a key element of iron transport, i.e., serum transferrin (Tf), is an essential growth factor for parasitic haemo-protozoans of the genus Trypanosoma. These are major mammalian parasites causing the diseases human African trypanosomosis (HAT) and animal trypanosomosis (AT). Using components of their well-characterized immune evasion system, bloodstream Trypanosoma brucei parasites adapt and scavenge for the mammalian host serum transferrin within their broad host range. The expression site associated genes (ESAG6 and 7) are utilized to construct a heterodimeric serum Tf binding complex which, within its niche in the flagellar pocket, and coupled to the trypanosomes’ fast endocytic rate, allows receptor-mediated acquisition of essential iron from their environment. This review summarizes current knowledge of the trypanosomal transferrin receptor (TfR), with emphasis on the structure and function of the receptor, both in physiological conditions as well as in conditions where the iron supply to parasites is being limited. Potential applications using current knowledge of the parasite receptor are also briefly discussed, primarily focused on potential therapeutic interventions.
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Affiliation(s)
- Christopher K. Kariuki
- Laboratory of Cellular and Molecular Interactions (CMIM), Vrije Universiteit Brussels, Brussels, 1050 Ixelles, Belgium;
- Department of Tropical and Infectious Diseases, Institute of Primate Research (IPR), 00502 Nairobi, Kenya
- Correspondence: (C.K.K.); (S.M.); Tel.: +322-629-1975 (C.K.K.); +82-32626-4207 (S.M.)
| | - Benoit Stijlemans
- Laboratory of Cellular and Molecular Interactions (CMIM), Vrije Universiteit Brussels, Brussels, 1050 Ixelles, Belgium;
- Myeloid Cell Immunology Lab, VIB Center for Inflammation Research, Brussels, 9052 Gent, Belgium
| | - Stefan Magez
- Laboratory of Cellular and Molecular Interactions (CMIM), Vrije Universiteit Brussels, Brussels, 1050 Ixelles, Belgium;
- Laboratory for Biomedical Research, Ghent University Global Campus, Yeonsu-Gu, Incheon 219220, Korea
- Correspondence: (C.K.K.); (S.M.); Tel.: +322-629-1975 (C.K.K.); +82-32626-4207 (S.M.)
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Castillo-Acosta VM, Ruiz-Pérez LM, Etxebarria J, Reichardt NC, Navarro M, Igarashi Y, Liekens S, Balzarini J, González-Pacanowska D. Carbohydrate-Binding Non-Peptidic Pradimicins for the Treatment of Acute Sleeping Sickness in Murine Models. PLoS Pathog 2016; 12:e1005851. [PMID: 27662652 PMCID: PMC5035034 DOI: 10.1371/journal.ppat.1005851] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/08/2016] [Indexed: 12/21/2022] Open
Abstract
Current treatments available for African sleeping sickness or human African trypanosomiasis (HAT) are limited, with poor efficacy and unacceptable safety profiles. Here, we report a new approach to address treatment of this disease based on the use of compounds that bind to parasite surface glycans leading to rapid killing of trypanosomes. Pradimicin and its derivatives are non-peptidic carbohydrate-binding agents that adhere to the carbohydrate moiety of the parasite surface glycoproteins inducing parasite lysis in vitro. Notably, pradimicin S has good pharmaceutical properties and enables cure of an acute form of the disease in mice. By inducing resistance in vitro we have established that the composition of the sugars attached to the variant surface glycoproteins are critical to the mode of action of pradimicins and play an important role in infectivity. The compounds identified represent a novel approach to develop drugs to treat HAT.
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Affiliation(s)
- Víctor M. Castillo-Acosta
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada), Spain
| | - Luis M. Ruiz-Pérez
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada), Spain
| | - Juan Etxebarria
- Glycotechnology Laboratory, CIC biomaGUNE, Parque Científico y Tecnológico de Gipuzkoa, San Sebastián, Spain
| | - Niels C. Reichardt
- Glycotechnology Laboratory, CIC biomaGUNE, Parque Científico y Tecnológico de Gipuzkoa, San Sebastián, Spain
- CIBER of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), San Sebastián, Spain
| | - Miguel Navarro
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada), Spain
| | - Yasuhiro Igarashi
- Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama, Japan
| | - Sandra Liekens
- KU Leuven, Rega Institute for Medical Research, Leuven, Belgium
| | - Jan Balzarini
- KU Leuven, Rega Institute for Medical Research, Leuven, Belgium
| | - Dolores González-Pacanowska
- Instituto de Parasitología y Biomedicina “López-Neyra”, Consejo Superior de Investigaciones Científicas, Parque Tecnológico de Ciencias de la Salud, Armilla (Granada), Spain
- * E-mail:
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Iron Homeostasis and Trypanosoma brucei Associated Immunopathogenicity Development: A Battle/Quest for Iron. BIOMED RESEARCH INTERNATIONAL 2015; 2015:819389. [PMID: 26090446 PMCID: PMC4450282 DOI: 10.1155/2015/819389] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 12/24/2022]
Abstract
African trypanosomosis is a chronic debilitating disease affecting the health and economic well-being of developing countries. The immune response during African trypanosome infection consisting of a strong proinflammatory M1-type activation of the myeloid phagocyte system (MYPS) results in iron deprivation for these extracellular parasites. Yet, the persistence of M1-type MYPS activation causes the development of anemia (anemia of chronic disease, ACD) as a most prominent pathological parameter in the mammalian host, due to enhanced erythrophagocytosis and retention of iron within the MYPS thereby depriving iron for erythropoiesis. In this review we give an overview of how parasites acquire iron from the host and how iron modulation of the host MYPS affects trypanosomosis-associated anemia development. Finally, we also discuss different strategies at the level of both the host and the parasite that can/might be used to modulate iron availability during African trypanosome infections.
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Production of recombinant proteins from protozoan parasites. Trends Parasitol 2010; 26:244-54. [PMID: 20189877 DOI: 10.1016/j.pt.2010.02.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2009] [Revised: 01/05/2010] [Accepted: 02/05/2010] [Indexed: 12/20/2022]
Abstract
Although the past decade has witnessed sequencing from an increasing number of parasites, modern high-throughput DNA sequencing technologies have the potential to generate complete genome sequences at even higher rates. Along with the discovery of genes that might constitute potential targets for chemotherapy or vaccination, the need for novel protein expression platforms has become a pressing matter. In addition to reviewing the advantages and limitations of the currently available and emerging expression systems, we discuss novel approaches that could overcome current limitations, including the 'pseudoparasite' concept, an expression platform in which the choice of the surrogate organism is based on its phylogenetic affinity to the target parasite, while taking advantage of the whole engineered organism as a vaccination adjuvant.
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