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Zhai B, Xie SC, Zhang J, He JJ, Zhu XQ. Dynamic RNA profiles in the small intestinal epithelia of cats after Toxoplasma gondii infection. Infect Dis Poverty 2023; 12:68. [PMID: 37491273 PMCID: PMC10367386 DOI: 10.1186/s40249-023-01121-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/14/2023] [Indexed: 07/27/2023] Open
Abstract
BACKGROUND Felids are the only definitive hosts of Toxoplasma gondii. However, the biological features of the feline small intestine following T. gondii infection are poorly understood. We investigated the changes in the expression of RNAs (including mRNAs, long non-coding RNAs and circular RNAs) in the small intestinal epithelia of cats following T. gondii infection to improve our understanding of the life cycle of T. gondii and cat responses to T. gondii infection. METHODS Fifteen cats were randomly assigned to five groups, and the infection groups were inoculated with 600 tissue cysts of the T. gondii Pru strain by gavage. The small intestinal epithelia of cats were collected at 6, 10, 14, and 30 days post infection (DPI). Using high-throughput RNA sequencing (RNA-seq), we investigated the changes in RNA expression. The expression levels of differentially expressed (DE) genes and non-coding RNAs (ncRNAs) identified by RNA-seq were validated by quantitative reverse transcription PCR (qRT-PCR). Differential expression was determined using the DESeq R package. RESULTS In total, 207 annotated lncRNAs, 20,552 novel lncRNAs, 3342 novel circRNAs and 19,409 mRNAs were identified. Among these, 70 to 344 DE mRNAs, lncRNAs and circRNAs were detected, and the post-cleavage binding sites between 725 ncRNAs and 2082 miRNAs were predicted. Using the co-location method, we predicted that a total of 235 lncRNAs target 1044 protein-coding genes, while the results of co-expression analysis revealed that 174 lncRNAs target 2097 mRNAs. Pathway enrichment analyses of the genes targeted by ncRNAs suggested that most ncRNAs were significantly enriched in immune or diseases-related pathways. NcRNA regulatory networks revealed that a single ncRNA could be directly or indirectly regulated by multiple genes or ncRNAs that could influence the immune response of cats. Co-expression analysis showed that 242 circRNAs, mainly involved in immune responses, were significantly associated with T. gondii infection. In contrast, 1352 protein coding RNAs, mainly involved in nucleic acid process/repair pathways or oocyte development pathways, were negatively associated with T. gondii infection. CONCLUSIONS This study is the first to reveal the expression profiles of circRNAs, lncRNAs and mRNAs in the cat small intestine following T. gondii infection and will facilitate the elucidation of the role of ncRNAs in the pathogenesis of T. gondii infection in its definitive host, thereby facilitating the development of novel intervention strategies against T. gondii infection in humans and animals.
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Affiliation(s)
- Bintao Zhai
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, 730050, Gansu, People's Republic of China
- State Key Laboratory for Animal Disease Control and Prevention, Key Laboratory of Veterinary Parasitology of Gansu Province, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, 730046, Gansu, People's Republic of China
| | - Shi-Chen Xie
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, 030801, Shanxi, People's Republic of China
- Research Center for Parasites & Vectors, College of Veterinary Medicine, Hunan Agricultural University, Changsha, 410128, Hunan, People's Republic of China
| | - Jiyu Zhang
- Key Laboratory of Veterinary Pharmaceutical Development, Ministry of Agriculture and Rural Affairs, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences, Lanzhou, 730050, Gansu, People's Republic of China
| | - Jun-Jun He
- Key Laboratory of Veterinary Public Health of Yunnan Province, College of Veterinary Medicine, Yunnan Agricultural University, Kunming, 650201, Yunnan, People's Republic of China.
| | - Xing-Quan Zhu
- Laboratory of Parasitic Diseases, College of Veterinary Medicine, Shanxi Agricultural University, Taigu, 030801, Shanxi, People's Republic of China.
- Key Laboratory of Veterinary Public Health of Yunnan Province, College of Veterinary Medicine, Yunnan Agricultural University, Kunming, 650201, Yunnan, People's Republic of China.
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2
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John A, M Bader S, Madiedo Soler N, Wiradiputri K, Tichkule S, Smyth ST, Ralph SA, Jex AR, Scott NE, Tonkin CJ, Goddard-Borger ED. Conservation, abundance, glycosylation profile, and localization of the TSP protein family in Cryptosporidium parvum. J Biol Chem 2023; 299:103006. [PMID: 36775128 PMCID: PMC10034466 DOI: 10.1016/j.jbc.2023.103006] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2022] [Revised: 02/05/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Cryptosporidium parvum is a zoonotic apicomplexan parasite and a common cause of diarrheal disease worldwide. The development of vaccines to prevent or limit infection remains an important goal for tackling cryptosporidiosis. At present, the only approved vaccine against any apicomplexan parasite targets a conserved adhesin possessing a thrombospondin repeat domain. C. parvum possesses 12 orthologous thrombospondin repeat domain-containing proteins known as CpTSP1-12, though little is known about these potentially important antigens. Here, we explore the architecture and conservation of the CpTSP protein family, as well as their abundance at the protein level within the sporozoite stage of the life cycle. We examine the glycosylation states of these proteins using a combination of glycopeptide enrichment techniques to demonstrate that these proteins are modified with C-, O-, and N-linked glycans. Using expansion microscopy, and an antibody against the C-linked mannose that is unique to the CpTSP protein family within C. parvum, we show that these proteins are found both on the cell surface and in structures that resemble the secretory pathway of C. parvum sporozoites. Finally, we generated a polyclonal antibody against CpTSP1 to show that it is found at the cell surface and within micronemes, in a pattern reminiscent of other apicomplexan motility-associated adhesins, and is present both in sporozoites and meronts. This work sheds new light on an understudied family of C. parvum proteins that are likely to be important to both parasite biology and the development of vaccines against cryptosporidiosis.
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Affiliation(s)
- Alan John
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Stefanie M Bader
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Niccolay Madiedo Soler
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Kharizta Wiradiputri
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Swapnil Tichkule
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Sean T Smyth
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Stuart A Ralph
- Department of Biochemistry and Pharmacology, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Aaron R Jex
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia
| | - Nichollas E Scott
- Department of Microbiology and Immunology, University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia.
| | - Christopher J Tonkin
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
| | - Ethan D Goddard-Borger
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia; Department of Medical Biology, University of Melbourne, Parkville, Victoria, Australia.
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Santos JM, Frénal K. Dominique Soldati-Favre: Bringing Toxoplasma gondii to the Molecular World. Front Cell Infect Microbiol 2022; 12:910611. [PMID: 35711657 PMCID: PMC9196188 DOI: 10.3389/fcimb.2022.910611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 04/29/2022] [Indexed: 11/25/2022] Open
Affiliation(s)
- Joana M Santos
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Karine Frénal
- Université Bordeaux, CNRS, Microbiologie Fondamentale et Pathogénicité, UMR 5234, Bordeaux, France
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Ricin B lectin-like proteins of the microsporidian Encephalitozoon cuniculi and Anncaliia algerae are involved in host-cell invasion. Parasitol Int 2021; 87:102518. [PMID: 34808329 DOI: 10.1016/j.parint.2021.102518] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/18/2021] [Accepted: 11/14/2021] [Indexed: 01/03/2023]
Abstract
Microsporidia are obligate intracellular pathogens capable of infecting a wide variety of hosts ranging from invertebrates to vertebrates. The infection process requires a step of prior adherence of Microsporidia to the surface of host cells. A few studies demonstrated the involvement of proteins containing a ricin-B lectin (RBL) domain in parasite infection. In this study Anncalia algerae and Encephalitozoon cuniculi genomes were screened by bioinformatic analysis to identify proteins with an extracellular prediction and possessing RBL-type carbohydrate-binding domains, being both potentially relevant factors contributing to host cell adherence. Three proteins named AaRBLL-1 and AaRBLL-2 from A. algerae and EcRBLL-1 from E. cuniculi, were selected and comparative analysis of sequences suggested their belonging to a multigenic family, with a conserved structural RBL domain despite a significant amino acid sequence divergence. The production of recombinant proteins and antibodies against the three proteins allowed their subcellular localization on the spore wall and/or the polar tube. Adherence inhibition assays based on pre-treatments with recombinant proteins or antibodies highlighted the significant decrease of the proliferation of both E. cuniculi and A. algerae, strongly suggesting that these proteins are involved in the infection process.
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De Mattos LC, Ferreira AIC, de Oliveira KY, Nakashima F, Brandão CC. The Potential Contribution of ABO, Lewis and Secretor Histo-Blood Group Carbohydrates in Infection by Toxoplasma gondii. Front Cell Infect Microbiol 2021; 11:671958. [PMID: 34222043 PMCID: PMC8251793 DOI: 10.3389/fcimb.2021.671958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 05/31/2021] [Indexed: 11/19/2022] Open
Abstract
The glycosyltransferases encoded by genes from the human ABO, Lewis, and Secretor histo-blood group systems synthesize part of the carbohydrate antigens in hematopoietic and non-hematopoietic tissues. The combined action of these glycosyltransferases strongly influences cell, tissue, mucosa, and exocrine secretion carbohydrate phenotypes, including those serving as habitat for mutualistic and pathogenic microorganisms. A set of reports investigated associations between Toxoplasma gondii infection and the ABO histo-blood group system, but the results are contradictory. As T. gondii uses the gastrointestinal tract as a route for infection, and in this organ, the expression of ABO, Lewis, and Secretor histo-blood group carbohydrates occurs, it is reasonable to suppose some biological relationship between them. This text reviewed association studies published in recent decades focusing on the potential contribution of the ABO, Lewis, and Secretor histo-blood group carbohydrates and infection by T. gondii.
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Affiliation(s)
- Luiz Carlos De Mattos
- Immunogenetics Laboratory, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil
| | - Ana Iara Costa Ferreira
- Immunogenetics Laboratory, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil
| | - Karina Younan de Oliveira
- Immunogenetics Laboratory, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil
| | - Fabiana Nakashima
- Immunogenetics Laboratory, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil
| | - Cinara Cássia Brandão
- Immunogenetics Laboratory, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil.,FAMERP Toxoplasma Research Group, Molecular Biology Department, Faculty of Medicine - FAMERP, São José do Rio Preto, Brazil
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Zhu J, Wang Y, Cao Y, Shen J, Yu L. Diverse Roles of TgMIC1/4/6 in the Toxoplasma Infection. Front Microbiol 2021; 12:666506. [PMID: 34220751 PMCID: PMC8247436 DOI: 10.3389/fmicb.2021.666506] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/25/2021] [Indexed: 11/23/2022] Open
Abstract
Toxoplasma gondii microneme is a specialized secretory organelle that discharges its contents at the apical tip of this apicomplexan parasite in a sequential and regulated manner. Increasing number of studies on microneme proteins (MICs) have shown them as a predominant and important role in host cell attachment, invasion, motility and pathogenesis. In this review, we summarize the research advances in one of the most important MICs complexes, TgMIC1/4/6, which will contribute to improve the understanding of the molecular mechanism of T. gondii infection and provide a theoretical basis for the effective control against T. gondii.
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Affiliation(s)
- Jinjin Zhu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yang Wang
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Yuanyuan Cao
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Jilong Shen
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
| | - Li Yu
- The Key Laboratory of Microbiology and Parasitology of Anhui Province, The Key Laboratory of Zoonoses of High Institutions in Anhui, Department of Microbiology and Parasitology, School of Basic Medical Sciences, Anhui Medical University, Hefei, China
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Xie Y, Xiao J, Zhou X, Gu X, He R, Xu J, Jing B, Peng X, Yang G. Global transcriptome landscape of the rabbit protozoan parasite Eimeria stiedae. Parasit Vectors 2021; 14:308. [PMID: 34099031 PMCID: PMC8186055 DOI: 10.1186/s13071-021-04811-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 05/25/2021] [Indexed: 11/26/2022] Open
Abstract
Background Coccidiosis caused by Eimeria stiedae is a widespread and economically significant disease of rabbits. The lack of studies on the life-cycle development and host interactions of E. stiedae at the molecular level has hampered our understanding of its pathogenesis. Methods In this study, we present a comprehensive transcriptome landscape of E. stiedae to illustrate its dynamic development from unsporulated oocysts to sporulated oocysts, merozoites, and gametocytes, and to identify genes related to parasite-host interactions during parasitism using combined PacBio single-molecule real-time and Illumina RNA sequencing followed by bioinformatics analysis and qRT-PCR validation. Results In total, 12,582 non-redundant full-length transcripts were generated with an average length of 1808 bp from the life-cycle stages of E. stiedae. Pairwise comparisons between stages revealed 8775 differentially expressed genes (DEGs) showing highly significant description changes, which compiled a snapshot of the mechanisms underlining asexual and sexual biology of E. stiedae including oocyst sporulation between unsporulated and sporulated oocysts; merozoite replication between sporulated oocysts and merozoites; and gametophyte development and gamete generation between merozoites and gametocytes. Further, 248 DEGs were grouped into nine series clusters and five groups by expression patterns, and showed that parasite–host interaction-related genes predominated in merozoites and gametocytes and were mostly involved in steroid biosynthesis and lipid metabolism and carboxylic acid. Additionally, co-expression analyses identified genes associated with development and host invasion in unsporulated and sporulated oocysts and immune interactions during gametocyte parasitism. Conclusions This is the first study, to our knowledge, to use the global transcriptome profiles to decipher molecular changes across the E. stiedae life cycle, and these results not only provide important information for the molecular characterization of E. stiedae, but also offer valuable resources to study other apicomplexan parasites with veterinary and public significance. Graphic Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04811-5.
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Affiliation(s)
- Yue Xie
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Jie Xiao
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Xuan Zhou
- Institute of Animal Genetics and Breeding, College of Animal Science and Technology, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Xiaobin Gu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Ran He
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Jing Xu
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Bo Jing
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Xuerong Peng
- Department of Chemistry, College of Life and Basic Science, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China
| | - Guangyou Yang
- Department of Parasitology, College of Veterinary Medicine, Sichuan Agricultural University, Chengdu, 611130, Sichuan, China.
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Ricci-Azevedo R, Mendonça-Natividade FC, Santana AC, Alcoforado Diniz J, Roque-Barreira MC. Microneme Proteins 1 and 4 From Toxoplasma gondii Induce IL-10 Production by Macrophages Through TLR4 Endocytosis. Front Immunol 2021; 12:655371. [PMID: 33912181 PMCID: PMC8071938 DOI: 10.3389/fimmu.2021.655371] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/22/2021] [Indexed: 01/09/2023] Open
Abstract
The protozoan parasite Toxoplasma gondii modulates host cell responses to favor its success in the early stage of infections by secreting proteins from its apical organelles. Some of these proteins, including microneme proteins (MICs) 1 and 4, trigger pro-inflammatory host cell responses. The lectins MIC1 and MIC4 interact with N-linked glycans on TLR2 and TLR4, activating NF-κB and producing IL-12, TNF-α, and IL-6. Interestingly, MIC1 and MIC4 also trigger secretion of the anti-inflammatory cytokine IL-10 through mechanisms as yet unknown. Herein, we show that the ability of these MICs to induce macrophages to produce IL-10 depends on TLR4 internalization from the cell surface. Macrophages subjected to blockade of endocytosis by Dynasore continued to release TNF-α, but failed to produce IL-10, in response to MIC1 or MIC4 exposure. Similarly, IL-10 was not produced by Dynasore-conditioned T. gondii-infected macrophages. Furthermore, MIC1- or MIC4-stimulated macrophages gained transient tolerance to LPS. We report a previously undiscovered mechanism by which well-defined T. gondii components inhibit a host inflammatory response.
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Affiliation(s)
- Rafael Ricci-Azevedo
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Flavia Costa Mendonça-Natividade
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Ana Carolina Santana
- Laboratory of Cellular and Molecular Biology of Mast Cells, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Juliana Alcoforado Diniz
- Laboratory of Molecular Parasitology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Maria Cristina Roque-Barreira
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
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Abstract
Some lectins of pathogens interact with host cells through the recognition of specific carbohydrates displayed on the mammals' cell surface. The microneme protein 1 (MIC1) from Toxoplasma gondii has a lectin domain that specifically binds sialic acid residues, often found in the terminal positions of N-glycans of mammalian cells. The necessary studies on the MIC1 biological roles have been limited initially by the laborious purification of the protein from T. gondii tachyzoites and the low yields verified. Then Escherichia coli has been transformed with a construct containing the MIC1 gene, and the obtained recombinant MIC1 (rMIC1) has been purified from the inclusion bodies. Herein, we detail the methodology of heterologous production and purification of rMIC1 and protocols to assay the rMIC1 lectin ability.
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Abstract
Micronemes are specialized secretory organelles present in all motile forms of apicomplexan parasites. Microneme vesicles hold adhesins and other proteins that are secreted to facilitate parasite attachment, invasion of host cells, and egress following replication-all processes indispensable for cell-to-cell transmission of these obligate intracellular parasites. Defining the signaling pathways that lead to microneme secretion is an important part of understanding the infectious cycle of apicomplexan parasites. However, the classical method of measuring microneme secretion by immunoblotting for microneme proteins in parasite excreted/secreted antigen (ESA) preparations is low-throughput and only semiquantitative. We recently reported a new luciferase-based method for measuring microneme secretion in a 96-well format with high sensitivity in the model apicomplexan Toxoplasma gondii. Here, we aim to elaborate on this detection method and review current practices for stimulating microneme secretion in vitro.
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Onile OS, Ojo GJ, Oyeyemi BF, Agbowuro GO, Fadahunsi AI. Development of multiepitope subunit protein vaccines against Toxoplasma gondii using an immunoinformatics approach. NAR Genom Bioinform 2020; 2:lqaa048. [PMID: 33575600 PMCID: PMC7671309 DOI: 10.1093/nargab/lqaa048] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/04/2020] [Accepted: 06/21/2020] [Indexed: 12/28/2022] Open
Abstract
Approximately one-third of the world’s human population is estimated to have been exposed to the parasite Toxoplasma gondii. Its prevalence is reportedly high in Ethiopia (74.80%) and Zimbabwe (68.58%), and is 40.40% in Nigeria. The adverse effect of this parasite includes a serious congenital disease in the developing fetus of pregnant women. After several efforts to eliminate the disease, only one licensed vaccine ‘Toxovax’ has been used to avoid congenital infections in sheep. The vaccine has been adjudged expensive coupled with adverse effects and short shelf life. The potential of vaccine to likely revert to virulent strain is a major reason why it has not been found suitable for human use, hence the need for a vaccine that will induce T and B memory cells capable of eliciting longtime immunity against the infection. This study presents immunoinformatics approaches to design a T. gondii-oriented multiepitope subunit vaccine with focus on micronemal proteins for the vaccine construct. The designed vaccine was subjected to antigenicity, immunogenicity, allergenicity and physicochemical parameter analyses. A 657-amino acid multiepitope vaccine was designed with the antigenicity probability of 0.803. The vaccine construct was classified as stable, non-allergenic, and highly immunogenic, thereby indicating the safety of the vaccine construct for human use.
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Affiliation(s)
- Olugbenga S Onile
- Biotechnology Programme, Department of Biological Sciences, Elizade University, 340211, Ilara-Mokin, Nigeria
| | - Glory J Ojo
- Biotechnology Programme, Department of Biological Sciences, Elizade University, 340211, Ilara-Mokin, Nigeria
| | - Bolaji Fatai Oyeyemi
- Molecular Biology Group, Department of Science Technology, The Federal Polytechnic, 360231, Ado-Ekiti, Ekiti State, Nigeria
| | - Gbenga O Agbowuro
- Biotechnology Programme, Department of Biological Sciences, Elizade University, 340211, Ilara-Mokin, Nigeria
| | - Adeyinka I Fadahunsi
- Biotechnology Programme, Department of Biological Sciences, Elizade University, 340211, Ilara-Mokin, Nigeria
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Costa Mendonça-Natividade F, Ricci-Azevedo R, Roque-Barreira MC. MIC4 from Toxoplasma gondii: A Lectin Acting as a Toll-Like Receptor Agonist. Methods Mol Biol 2020; 2132:379-389. [PMID: 32306345 DOI: 10.1007/978-1-0716-0430-4_37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Tachyzoites, which are infective forms of Toxoplasma gondii, use their actinomyosin system to move over surfaces and invade host cells. Central to this process is the regulated release of micronemes organelles contents. The microneme protein 4 (MIC4) has the property to recognize galactosides residues linked to glycoproteins on the host cell surface. This property allows that MIC4 binds to TLR2- and TLR4 N-linked glycans and promote the activation of cell innate immune cells and secretion of inflammatory cytokines, acting on resistance against the parasite. Obtention of MIC4 from T. gondii requires several purification steps, is time-consuming and provides low yield. Therefore, this section details the protocol for prokaryotic expression, production, and purification of recombinant MIC4 (rMIC4) and for experimental assays to confirm its biological activity.
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Affiliation(s)
- Flávia Costa Mendonça-Natividade
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto, SP, Brazil
| | - Rafael Ricci-Azevedo
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto, SP, Brazil
| | - Maria Cristina Roque-Barreira
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto, SP, Brazil.
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Costa Mendonça-Natividade F, Duque Lopes C, Ricci-Azevedo R, Sardinha-Silva A, Figueiredo Pinzan C, Paiva Alegre-Maller AC, L Nohara L, B Carneiro A, Panunto-Castelo A, C Almeida I, Roque-Barreira MC. Receptor Heterodimerization and Co-Receptor Engagement in TLR2 Activation Induced by MIC1 and MIC4 from Toxoplasma gondii. Int J Mol Sci 2019; 20:ijms20205001. [PMID: 31658592 PMCID: PMC6829480 DOI: 10.3390/ijms20205001] [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: 08/15/2019] [Revised: 09/17/2019] [Accepted: 09/30/2019] [Indexed: 01/07/2023] Open
Abstract
The microneme organelles of Toxoplasma gondii tachyzoites release protein complexes (MICs), including one composed of the transmembrane protein MIC6 plus MIC1 and MIC4. In this complex, carbohydrate recognition domains of MIC1 and MIC4 are exposed and interact with terminal sialic acid and galactose residues, respectively, of host cell glycans. Recently, we demonstrated that MIC1 and MIC4 binding to the N-glycans of Toll-like receptor (TLR) 2 and TLR4 on phagocytes triggers cell activation and pro-inflammatory cytokine production. Herein, we investigated the requirement for TLR2 heterodimerization and co-receptors in MIC-induced responses, as well as the signaling molecules involved. We used MICs to stimulate macrophages and HEK293T cells transfected with TLR2 and TLR1 or TLR6, both with or without the co-receptors CD14 and CD36. Then, the cell responses were analyzed, including nuclear factor-kappa B (NF-κB) activation and cytokine production, which showed that (1) only TLR2, among the studied factors, is crucial for MIC-induced cell activation; (2) TLR2 heterodimerization augments, but is not critical for, activation; (3) CD14 and CD36 enhance the response to MIC stimulus; and (4) MICs activate cells through a transforming growth factor beta-activated kinase 1 (TAK1)-, mammalian p38 mitogen-activated protein kinase (p38)-, and NF-κB-dependent pathway. Remarkably, among the studied factors, the interaction of MIC1 and MIC4 with TLR2 N-glycans is sufficient to induce cell activation, which promotes host protection against T. gondii infection.
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Affiliation(s)
- Flávia Costa Mendonça-Natividade
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Carla Duque Lopes
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Rafael Ricci-Azevedo
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Aline Sardinha-Silva
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Camila Figueiredo Pinzan
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Ana Claudia Paiva Alegre-Maller
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
| | - Lilian L Nohara
- Border Biomedical Research Center (BBRC), Department of Biological Sciences, University of Texas at El Paso (UTEP), El Paso, TX 79968, USA.
| | - Alan B Carneiro
- Border Biomedical Research Center (BBRC), Department of Biological Sciences, University of Texas at El Paso (UTEP), El Paso, TX 79968, USA.
- Institute of Medical Biochemistry, Program of Molecular Biology and Biotechnology at Federal University of Rio de Janeiro (UFRJ), Rio de Janeiro RJ 21941-599, Brazil.
| | - Ademilson Panunto-Castelo
- Department of Biology, Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo USP (FFCLRP/USP), Ribeirão Preto SP 14040-900, Brazil.
| | - Igor C Almeida
- Border Biomedical Research Center (BBRC), Department of Biological Sciences, University of Texas at El Paso (UTEP), El Paso, TX 79968, USA.
| | - Maria Cristina Roque-Barreira
- Laboratory of Immunochemistry and Glycobiology, Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo (FMRP/USP), Ribeirão Preto SP 14049-900, Brazil.
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The lectin-specific activity of Toxoplasma gondii microneme proteins 1 and 4 binds Toll-like receptor 2 and 4 N-glycans to regulate innate immune priming. PLoS Pathog 2019; 15:e1007871. [PMID: 31226171 PMCID: PMC6608980 DOI: 10.1371/journal.ppat.1007871] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 07/03/2019] [Accepted: 05/25/2019] [Indexed: 01/01/2023] Open
Abstract
Infection of host cells by Toxoplasma gondii is an active process, which is regulated by secretion of microneme (MICs) and rhoptry proteins (ROPs and RONs) from specialized organelles in the apical pole of the parasite. MIC1, MIC4 and MIC6 assemble into an adhesin complex secreted on the parasite surface that functions to promote infection competency. MIC1 and MIC4 are known to bind terminal sialic acid residues and galactose residues, respectively and to induce IL-12 production from splenocytes. Here we show that rMIC1- and rMIC4-stimulated dendritic cells and macrophages produce proinflammatory cytokines, and they do so by engaging TLR2 and TLR4. This process depends on sugar recognition, since point mutations in the carbohydrate-recognition domains (CRD) of rMIC1 and rMIC4 inhibit innate immune cells activation. HEK cells transfected with TLR2 glycomutants were selectively unresponsive to MICs. Following in vitro infection, parasites lacking MIC1 or MIC4, as well as expressing MIC proteins with point mutations in their CRD, failed to induce wild-type (WT) levels of IL-12 secretion by innate immune cells. However, only MIC1 was shown to impact systemic levels of IL-12 and IFN-γ in vivo. Together, our data show that MIC1 and MIC4 interact physically with TLR2 and TLR4 N-glycans to trigger IL-12 responses, and MIC1 is playing a significant role in vivo by altering T. gondii infection competency and murine pathogenesis. Toxoplasmosis is caused by the protozoan Toxoplasma gondii, belonging to the Apicomplexa phylum. This phylum comprises important parasites able to infect a broad diversity of animals, including humans. A particularity of T. gondii is its ability to invade virtually any nucleated cell of all warm-blooded animals through an active process, which depends on the secretion of adhesin proteins. These proteins are discharged by specialized organelles localized in the parasite apical region, and termed micronemes and rhoptries. We show in this study that two microneme proteins from T. gondii utilize their adhesion activity to stimulate innate immunity. These microneme proteins, denoted MIC1 and MIC4, recognize specific sugars on receptors expressed on the surface of mammalian immune cells. This binding activates these innate immune cells to secrete cytokines, which promotes efficient host defense mechanisms against the parasite and regulate their pathogenesis. This activity promotes a chronic infection by controlling parasite replication during acute infection.
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Secretory Microneme Proteins Induce T-Cell Recall Responses in Mice Chronically Infected with Toxoplasma gondii. mSphere 2019; 4:4/1/e00711-18. [PMID: 30814319 PMCID: PMC6393730 DOI: 10.1128/msphere.00711-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Current diagnosis of toxoplasmosis relies almost exclusively on antibody detection, and while detection of IgG provides a useful estimate of prior infection, it does not alone indicate immune status. In contrast, detection of IFN-γ responses to T. gondii antigens has been used to monitor immune responsiveness in HIV-infected patients, thus providing valuable predictions about the potential for disease reactivation. However, specific T. gondii antigens that can be used in assays to detect cellular immunity remain largely undefined. In this study, we examined the diagnostic potential of microneme antigens of T. gondii using IFN-γ detection assays. Our findings demonstrate that MIC antigens (MIC1, MIC3, MIC4, and MIC6) elicit IFN-γ responses from memory T cells in chronically infected mice. Monitoring IFN-γ production by T cells stimulated with MIC antigens provided high sensitivity and specificity for detection of T. gondii infection in mice. Taken together, these studies suggest that microneme antigens might be useful as an adjunct to serological testing to monitor immune status during infection. Microneme (MIC) proteins play important roles in the recognition, adhesion, and invasion of host cells by Toxoplasma gondii. Previous studies have shown that MIC proteins are highly immunogenic in the mouse and recognized by human serum antibodies. Here we report that T. gondii antigens MIC1, MIC3, MIC4, and MIC6 were capable of inducing memory responses leading to production of gamma interferon (IFN-γ) by T cells from T. gondii-infected mice. Production of IFN-γ was demonstrated using enzyme-linked immunosorbent spot (ELISPOT) assay and also intracellular cytokine staining. All four MIC antigens displayed very high sensitivity (100%) and specificity (86 to 100%) for detecting chronic infection. Interestingly, IFN-γ was produced by both CD4+ and CD8+ T cells in BALB/c mice but primarily by CD4+ T cells in C57BL/6 mice. Phenotypic characterization of IFN-γ-producing CD4+ and CD8+ T cells in BALB/c mice and CD4+ T cells in C57BL/6 mice revealed effector memory T cells (CD44hi CD62Llo) as the predominant cells that contributed to IFN-γ production in response to MIC antigens. Effector memory responses were seen in mice of different major histocompatibility complex class II (MHC-II) haplotypes, suggesting that MIC antigens contain epitopes that are broadly recognized. IMPORTANCE Current diagnosis of toxoplasmosis relies almost exclusively on antibody detection, and while detection of IgG provides a useful estimate of prior infection, it does not alone indicate immune status. In contrast, detection of IFN-γ responses to T. gondii antigens has been used to monitor immune responsiveness in HIV-infected patients, thus providing valuable predictions about the potential for disease reactivation. However, specific T. gondii antigens that can be used in assays to detect cellular immunity remain largely undefined. In this study, we examined the diagnostic potential of microneme antigens of T. gondii using IFN-γ detection assays. Our findings demonstrate that MIC antigens (MIC1, MIC3, MIC4, and MIC6) elicit IFN-γ responses from memory T cells in chronically infected mice. Monitoring IFN-γ production by T cells stimulated with MIC antigens provided high sensitivity and specificity for detection of T. gondii infection in mice. Taken together, these studies suggest that microneme antigens might be useful as an adjunct to serological testing to monitor immune status during infection.
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Abstract
Toxoplasma gondii is a highly prevalent protozoon that can infect all warm-blooded animals, including humans. It is frequently used as an Apicomplexan parasite model in
research. In this review, the invasion mechanism of T. gondii is described as a representative Apicomplexan parasite. The invasion machinery of T. gondii
consists of the moving junction and the glideosome, which is a specific motor system for Apicomplexan parasites. I provide details about the moving junction, parasite-secreted proteins and
host adhesion receptors, the glideosome, and calcium signaling, which generates the power for the gliding mobility of T. gondii. A detailed understanding of parasite
invasion can be useful for the development of new effective drugs to inhibit this event and disrupt the Apicomplexan life cycle.
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Affiliation(s)
- Kentaro Kato
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
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Fushinobu S. Conformations of the type-1 lacto-N-biose I unit in protein complex structures. Acta Crystallogr F Struct Biol Commun 2018; 74:473-479. [PMID: 30084396 PMCID: PMC6096478 DOI: 10.1107/s2053230x18006568] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 04/27/2018] [Indexed: 11/10/2022] Open
Abstract
The lacto-N-biose I (Galβ1-3GlcNAc; LNB) disaccharide is present as a core unit of type-1 blood group antigens of animal glycoconjugates and milk oligosaccharides. Type-1 antigens often serve as cell-surface receptors for infection by pathogens. LNB in human milk oligosaccharides functions as a prebiotic for bifidobacteria and plays a key role in the symbiotic relationship of commensal gut microbes in infants. Protein Data Bank (PDB) entries exhibiting the LNB unit were investigated using the GlycoMapsDB web tool. There are currently 159 β-LNB and nine α-LNB moieties represented in ligands in the database. β-LNB and α-LNB moieties occur in 74 and six PDB entries, respectively, as NCS copies. The protein and enzyme structures are from various organisms including humans (galectins), viruses (haemagglutinin and capsid proteins), a pathogenic fungus, a parasitic nematode and protist, pathogenic bacteria (adhesins) and a symbiotic bacterium (a solute-binding protein of an ABC transporter). The conformations of LNB-containing glycans in enzymes vary significantly according to their mechanism of substrate recognition and catalysis. Analysis of glycosidic bond conformations indicated that the binding modes are significantly different in proteins adapted for modified or unmodified glycans.
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Affiliation(s)
- Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
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Immunomolecular Characterization of MIC-1, a Novel Antigen in Babesia bigemina, Which Contains Conserved and Immunodominant B-Cell Epitopes that Induce Neutralizing Antibodies. Vet Sci 2018; 5:vetsci5020032. [PMID: 29570654 PMCID: PMC6024600 DOI: 10.3390/vetsci5020032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 03/19/2018] [Accepted: 03/21/2018] [Indexed: 11/20/2022] Open
Abstract
Babesia bigemina is one of the most prevalent species causing bovine babesiosis around the world. Antigens involved in host cell invasion are vaccine targets for this disease but are largely unknown in this species. The invasion process of Babesia spp. into erythrocytes involves membrane proteins from the apical complex. A protein stored in the micronemes, called Micronemal Protein 1 (MIC-1), contains a sialic acid binding domain that participates in the invasion process of host cells and is a vaccine candidate in other apicomplexan parasites. It is not known if there is a homologous gene for mic-1 in B. bigemina. Therefore, the aim of this study was to characterize the mic-1 gene homologue in Babesia bigemina. A gene was found with a microneme adhesive repeat (MAR) domain in the predicted amino acid sequence. Transcription was determined by reverse transcription polymerase chain reaction (RT-PCR). Subsequently, antibodies against peptides containing conserved B-cell epitopes were used to confirm the expression of MIC-1 in intraerythrocytic merozoites. The presence of anti MIC-1 antibodies in cattle naturally infected with B. bigemina was determined and up to 97.4% of the cattle sera (113 out of 116) identified MIC-1 using enzyme-linked immunosorbent assay (ELISA) methods. Finally, antibodies against MIC-1 were able to block 70% merozoite invasion in-vitro.
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Schubert M. Insights into Carbohydrate Recognition by 3D Structure Determination of Protein–Carbohydrate Complexes Using NMR. NMR IN GLYCOSCIENCE AND GLYCOTECHNOLOGY 2017:101-122. [DOI: 10.1039/9781782623946-00101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
This chapter provides an overview of protein–carbohydrate complex structures determined with NMR spectroscopy and deposited in the Protein Data Bank (PDB). These 14 structures include protein–carbohydrate interactions ranging from nanomolar to millimolar affinities. Two complexes are discussed in detail, one representing a tightly bound complex and one a weak but specific interaction. This review illustrates that NMR spectroscopy is a competitive method for three-dimensional structure determination of protein–carbohydrate complexes, especially in the case of weak interactions. The number of biological functions in which protein–carbohydrate interactions are involved is steadily growing. Essential functions of the immune system such as the distinction between self and non-self, or the resolution of inflammation, involve critical protein–carbohydrate recognition events. It is therefore expected that by providing atomic details, NMR spectroscopy can make a significant contribution in the near future to unexplored pathways of the immune system and of many other biological processes.
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Affiliation(s)
- Mario Schubert
- Department of Molecular Biology, University of Salzburg 5020 Salzburg Austria
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Aquino I, Alcalá Y, Gutiérrez L, Tapia G, Jung H, Sumano H. In vivo anticoccidial activity of quinfamide in broilers: a preliminary report. ITALIAN JOURNAL OF ANIMAL SCIENCE 2016. [DOI: 10.1080/1828051x.2016.1229585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Santos A, Bueno PR. Glycoprotein assay based on the optimized immittance signal of a redox tagged and lectin-based receptive interface. Biosens Bioelectron 2016; 83:368-78. [DOI: 10.1016/j.bios.2016.04.043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/08/2016] [Accepted: 04/14/2016] [Indexed: 12/29/2022]
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Twenty-six circulating antigens and two novel diagnostic candidate molecules identified in the serum of canines with experimental acute toxoplasmosis. Parasit Vectors 2016; 9:374. [PMID: 27357215 PMCID: PMC4928332 DOI: 10.1186/s13071-016-1643-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 06/13/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The protozoan Toxoplasma gondii is a pathogen that causes severe opportunistic disease in a wide range of hosts. Efficient methods to diagnose acute T. gondii infection are essential for the administration of appropriate treatments and to reduce economic losses. In animals with acute infections, circulating antigens (CAgs) were detected as early as two days post-infection; these CAgs were reliable diagnostic indicators of acute infection. However, only a limited number of CAgs have been identified to date. The objective of this study was to identify a broader spectrum of CAgs and to explore novel diagnostic candidates in serum. METHODS A canine model of acute toxoplasmiosis was established. For this purpose, six dogs were infected by intraperitoneal inoculation of tachyzoites. The CAgs spectrum in the serum was identified with the immunoprecipitation-shotgun approach. Two CAgs with low homology to other species, coronin protein (TgCOR) and ELMO protein (TgELMO), were heterologously expressed in Escherichia coli. Polyclonal antibodies against these two proteins were prepared, and the presence of these proteins in the serum was verified by Western blotting. The two CAgs were detected and evaluated by indirect ELISA methods. RESULTS The CAgs levels peaked between two and five days after inoculation, and twenty-six CAgs were identified. Western blotting showed the presence of the two proteins in the serum during acute infection. Based on ELISA tests, the two CAgs were detected during acute infection. CONCLUSIONS We identified twenty-six CAgs in the serum of canines with experimental acute toxoplasmosis and discovered two novel diagnostic candidates. We also provide new insights into the diagnosis of acute toxoplasmosis.
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Pinzan CF, Sardinha-Silva A, Almeida F, Lai L, Lopes CD, Lourenço EV, Panunto-Castelo A, Matthews S, Roque-Barreira MC. Vaccination with Recombinant Microneme Proteins Confers Protection against Experimental Toxoplasmosis in Mice. PLoS One 2015; 10:e0143087. [PMID: 26575028 PMCID: PMC4648487 DOI: 10.1371/journal.pone.0143087] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 10/04/2015] [Indexed: 12/24/2022] Open
Abstract
Toxoplasmosis, a zoonotic disease caused by Toxoplasma gondii, is an important public health problem and veterinary concern. Although there is no vaccine for human toxoplasmosis, many attempts have been made to develop one. Promising vaccine candidates utilize proteins, or their genes, from microneme organelle of T. gondii that are involved in the initial stages of host cell invasion by the parasite. In the present study, we used different recombinant microneme proteins (TgMIC1, TgMIC4, or TgMIC6) or combinations of these proteins (TgMIC1-4 and TgMIC1-4-6) to evaluate the immune response and protection against experimental toxoplasmosis in C57BL/6 mice. Vaccination with recombinant TgMIC1, TgMIC4, or TgMIC6 alone conferred partial protection, as demonstrated by reduced brain cyst burden and mortality rates after challenge. Immunization with TgMIC1-4 or TgMIC1-4-6 vaccines provided the most effective protection, since 70% and 80% of mice, respectively, survived to the acute phase of infection. In addition, these vaccinated mice, in comparison to non-vaccinated ones, showed reduced parasite burden by 59% and 68%, respectively. The protective effect was related to the cellular and humoral immune responses induced by vaccination and included the release of Th1 cytokines IFN-γ and IL-12, antigen-stimulated spleen cell proliferation, and production of antigen-specific serum antibodies. Our results demonstrate that microneme proteins are potential vaccines against T. gondii, since their inoculation prevents or decreases the deleterious effects of the infection.
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Affiliation(s)
- Camila Figueiredo Pinzan
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Aline Sardinha-Silva
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Fausto Almeida
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Livia Lai
- Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Carla Duque Lopes
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Elaine Vicente Lourenço
- Department of Medicine, Division of Rheumatology, University of California Los Angeles, Los Angeles, California, 90095–1670, United States of America
| | - Ademilson Panunto-Castelo
- Department of Biology, School of Philosophy, Sciences and Literature of Ribeirão Preto, University of Sao Paulo, Ribeirão Preto, São Paulo, Brazil
| | - Stephen Matthews
- Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom
| | - Maria Cristina Roque-Barreira
- Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
- * E-mail:
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Santos A, Carvalho FC, Roque-Barreira MC, Zorzetto-Fernandes AL, Gimenez-Romero D, Monzó I, Bueno PR. Evidence for Conformational Mechanism on the Binding of TgMIC4 with β-Galactose-Containing Carbohydrate Ligand. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:12111-12119. [PMID: 26488670 DOI: 10.1021/acs.langmuir.5b03141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
A deeper understanding of the role of sialic/desialylated groups during TgMIC4-glycoproteins interactions has importance to better clarify the odd process of host cell invasion by members of the apicomplexan phylum. Within this context, we evaluated the interaction established by recombinant TgMIC4 (the whole molecule) with sialylated (bovine fetuin) and desialylated (asialofetuin) glycoproteins by using functionalized quartz crystal microbalance with dissipation monitoring (QCM-D). A suitable receptive surface containing recombinant TgMIC4 for monitoring β-galactose-containing carbohydrate ligand (limit of quantification ∼ 40 μM) was designed and used as biomolecular recognition platform to study the binding and conformational mechanisms of TgMIC4 during the interaction with glycoprotein containing (fetuin), or not, terminal sialic group (asialofetuin). It was inferred that the binding/interaction monitoring depends on the presence/absence of sialic groups in target protein and is possible to be differentiated through a slower binding kinetic step using QCM-D approach (which we are inferring to be thus associated with β-galactose ligand). This slower binding/interaction step is likely supposed (from mechanical energetic analysis obtained in QCM-D measurements) to be involved with Toxoplasma gondii (the causative agent of toxoplasmosis) parasitic invasion accompanied by ligand (galactose) induced binding conformational change (i.e., cell internalization process can be additionally dependent on structural conformational changes, controlled by the absence of sialic groups and to the specific binding with galactose), in addition to TgMIC4-glycoprotein solely recognition binding process.
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Affiliation(s)
- Adriano Santos
- Institute of Chemistry, Physical Chemistry Department, Nanobionics Laboratory, Universidade Estadual Paulista (São Paulo State University) , CP 355, 14800-060 Araraquara, São Paulo, Brazil
| | - Fernanda C Carvalho
- Institute of Chemistry, Physical Chemistry Department, Nanobionics Laboratory, Universidade Estadual Paulista (São Paulo State University) , CP 355, 14800-060 Araraquara, São Paulo, Brazil
| | - Maria-Cristina Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP) , Av. dos Bandeirantes, 3900, Ribeirão Preto, 14049-900 São Paulo, Brazil
| | - André Luiz Zorzetto-Fernandes
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo (USP) , Av. dos Bandeirantes, 3900, Ribeirão Preto, 14049-900 São Paulo, Brazil
| | - David Gimenez-Romero
- Departamento de Química Física, Facultad de Química, Universitat de València , Avda. Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
| | - Isidro Monzó
- Departamento de Química Física, Facultad de Química, Universitat de València , Avda. Dr. Moliner 50, 46100 Burjassot, Valencia, Spain
| | - Paulo R Bueno
- Institute of Chemistry, Physical Chemistry Department, Nanobionics Laboratory, Universidade Estadual Paulista (São Paulo State University) , CP 355, 14800-060 Araraquara, São Paulo, Brazil
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Huynh MH, Liu B, Henry M, Liew L, Matthews SJ, Carruthers VB. Structural basis of Toxoplasma gondii MIC2-associated protein interaction with MIC2. J Biol Chem 2014; 290:1432-41. [PMID: 25411252 DOI: 10.1074/jbc.m114.613646] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Toxoplasma gondii parasites must actively invade host cells to propagate. Secretory microneme proteins have been shown to be important for both gliding motility and active invasion. MIC2-M2AP is a protein complex that is essential for productive motility and rapid invasion by binding to host cell surface receptors. To investigate the architecture of the MIC2 and M2AP complex, we identified the minimal domains sufficient for interaction and solved the NMR solution structure of the globular domain of M2AP. We found that M2AP adopts a modified galectin fold similar to the C-terminal domain of another microneme protein, MIC1. NMR and immunoprecipitation analyses implicated hydrophobic residues on one face of the M2AP galectin fold in binding to the membrane proximal sixth thrombospondin type I repeat domain of MIC2. Our findings provide a second example of a galectin fold adapted for microneme protein-protein interactions and suggest a conserved strategy for the assembly and folding of diverse protein complexes.
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Affiliation(s)
- My-Hang Huynh
- From the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109 and
| | - Bing Liu
- the Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Maud Henry
- the Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Lloyd Liew
- the Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Stephen J Matthews
- the Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Vern B Carruthers
- From the Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109 and
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Xu Y, Plechanovová A, Simpson P, Marchant J, Leidecker O, Kraatz S, Hay RT, Matthews SJ. Structural insight into SUMO chain recognition and manipulation by the ubiquitin ligase RNF4. Nat Commun 2014; 5:4217. [PMID: 24969970 PMCID: PMC4083429 DOI: 10.1038/ncomms5217] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/27/2014] [Indexed: 01/08/2023] Open
Abstract
The small ubiquitin-like modifier (SUMO) can form polymeric chains that are important signals in cellular processes such as meiosis, genome maintenance and stress response. The SUMO-targeted ubiquitin ligase RNF4 engages with SUMO chains on linked substrates and catalyses their ubiquitination, which targets substrates for proteasomal degradation. Here we use a segmental labelling approach combined with solution nuclear magnetic resonance (NMR) spectroscopy and biochemical characterization to reveal how RNF4 manipulates the conformation of the SUMO chain, thereby facilitating optimal delivery of the distal SUMO domain for ubiquitin transfer.
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Affiliation(s)
- Yingqi Xu
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
- These authors contributed equally to this work
| | - Anna Plechanovová
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
- These authors contributed equally to this work
| | - Peter Simpson
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Jan Marchant
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Orsolya Leidecker
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Sebastian Kraatz
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
| | - Ronald T. Hay
- Centre for Gene Regulation and Expression, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Steve J. Matthews
- Centre for Structural Biology, Department of Life Sciences, Imperial College London, South Kensington, London SW7 2AZ, UK
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Paing MM, Tolia NH. Multimeric assembly of host-pathogen adhesion complexes involved in apicomplexan invasion. PLoS Pathog 2014; 10:e1004120. [PMID: 24945143 PMCID: PMC4055764 DOI: 10.1371/journal.ppat.1004120] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- May M. Paing
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, Saint Louis, Missouri, United States of America
| | - Niraj H. Tolia
- Department of Molecular Microbiology and Microbial Pathogenesis, Washington University School of Medicine, Saint Louis, Missouri, United States of America
- * E-mail:
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Chapman HD, Barta JR, Blake D, Gruber A, Jenkins M, Smith NC, Suo X, Tomley FM. A selective review of advances in coccidiosis research. ADVANCES IN PARASITOLOGY 2014; 83:93-171. [PMID: 23876872 DOI: 10.1016/b978-0-12-407705-8.00002-1] [Citation(s) in RCA: 161] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Coccidiosis is a widespread and economically significant disease of livestock caused by protozoan parasites of the genus Eimeria. This disease is worldwide in occurrence and costs the animal agricultural industry many millions of dollars to control. In recent years, the modern tools of molecular biology, biochemistry, cell biology and immunology have been used to expand greatly our knowledge of these parasites and the disease they cause. Such studies are essential if we are to develop new means for the control of coccidiosis. In this chapter, selective aspects of the biology of these organisms, with emphasis on recent research in poultry, are reviewed. Topics considered include taxonomy, systematics, genetics, genomics, transcriptomics, proteomics, transfection, oocyst biogenesis, host cell invasion, immunobiology, diagnostics and control.
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Affiliation(s)
- H David Chapman
- Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas, USA.
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29
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Palma AS, Feizi T, Childs RA, Chai W, Liu Y. The neoglycolipid (NGL)-based oligosaccharide microarray system poised to decipher the meta-glycome. Curr Opin Chem Biol 2014; 18:87-94. [PMID: 24508828 DOI: 10.1016/j.cbpa.2014.01.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Revised: 01/09/2014] [Accepted: 01/09/2014] [Indexed: 01/01/2023]
Abstract
The neoglycolipid (NGL) technology is the basis of a state-of-the-art oligosaccharide microarray system. The NGL-based microarray system in the Glycosciences Laboratory Imperial College London (http://www3.imperial.ac.uk/glycosciences) is one of the two leading platforms for glycan microarrays, being offered for screening analyses to the broad biomedical community. Highlighted in this review are the sensitivity of the analysis system and, coupled with mass spectrometry, the provision for generating 'designer' microarrays from glycomes to identify novel ligands of biological relevance. Among recent applications are assignments of ligands for apicomplexan parasites, pandemic 2009 influenza virus, polyoma and reoviruses, an innate immune receptor against fungal pathogens, Dectin-1, and a novel protein of the endoplasmic reticulum, malectin; also the characterization of an elusive cancer-associated antigen. Some other contemporary advances in glycolipid-containing arrays and microarrays are also discussed.
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Affiliation(s)
- Angelina S Palma
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, United Kingdom; REQUIMTE/CQFB, Faculty of Science and Technology, New University of Lisbon, Caparica, Portugal.
| | - Ten Feizi
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, United Kingdom.
| | - Robert A Childs
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, United Kingdom
| | - Wengang Chai
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, United Kingdom
| | - Yan Liu
- The Glycosciences Laboratory, Department of Medicine, Imperial College London, United Kingdom.
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30
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Fujimoto Z, Tateno H, Hirabayashi J. Lectin structures: classification based on the 3-D structures. Methods Mol Biol 2014; 1200:579-606. [PMID: 25117265 DOI: 10.1007/978-1-4939-1292-6_46] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Recent progress in structural biology has elucidated the three-dimensional structures and carbohydrate-binding mechanisms of most lectin families. Lectins are classified into 48 families based on their three-dimensional structures. A ribbon drawing gallery of the crystal and solution structures of representative lectins or lectin-like proteins is appended and may help to convey the diversity of lectin families, the similarity and differences between lectin families, as well as the carbohydrate-binding architectures of lectins.
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Affiliation(s)
- Zui Fujimoto
- Biomolecular Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, 305-8602, Japan,
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31
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Neu U, Khan ZM, Schuch B, Palma AS, Liu Y, Pawlita M, Feizi T, Stehle T. Structures of B-lymphotropic polyomavirus VP1 in complex with oligosaccharide ligands. PLoS Pathog 2013; 9:e1003714. [PMID: 24204265 PMCID: PMC3814675 DOI: 10.1371/journal.ppat.1003714] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 09/03/2013] [Indexed: 12/04/2022] Open
Abstract
B-Lymphotropic Polyomavirus (LPyV) serves as a paradigm of virus receptor binding and tropism, and is the closest relative of the recently discovered Human Polyomavirus 9 (HPyV9). LPyV infection depends on sialic acid on host cells, but the molecular interactions underlying LPyV-receptor binding were unknown. We find by glycan array screening that LPyV specifically recognizes a linear carbohydrate motif that contains α2,3-linked sialic acid. High-resolution crystal structures of the LPyV capsid protein VP1 alone and in complex with the trisaccharide ligands 3′-sialyllactose and 3′-sialyl-N-acetyl-lactosamine (3SL and 3SLN, respectively) show essentially identical interactions. Most contacts are contributed by the sialic acid moiety, which is almost entirely buried in a narrow, preformed cleft at the outer surface of the capsid. The recessed nature of the binding site on VP1 and the nature of the observed glycan interactions differ from those of related polyomaviruses and most other sialic acid-binding viruses, which bind sialic acid in shallow, more exposed grooves. Despite their different modes for recognition, the sialic acid binding sites of LPyV and SV40 are half-conserved, hinting at an evolutionary strategy for diversification of binding sites. Our analysis provides a structural basis for the observed specificity of LPyV for linear glycan motifs terminating in α2,3-linked sialic acid, and links the different tropisms of known LPyV strains to the receptor binding site. It also serves as a useful template for understanding the ligand-binding properties and serological crossreactivity of HPyV9. Viruses must engage specific receptors on host cells in order to initiate infection. The type of receptor and its concentration on cells determine viral spread and tropism, but for many viruses, the receptor and the mode of recognition by the virus are not known. We have characterized the structural requirements for receptor binding of B-lymphotropic polyomavirus (LPyV). This virus was originally isolated from African Green Monkey lymph node cultures and attracted interest because of its narrow tropism for a human tumor cell line. LPyV is also the closest relative of the recently discovered Human Polyomavirus 9 (HPyV9). We screened the LPyV coat protein VP1 on an carbohydrate microarray and found that it specifically recognizes a linear sugar motif that terminates in α2,3-linked sialic acid. We then determined the structures LPyV VP1 bound to these carbohydrates. The protein has a preformed, deeply recessed binding site for sialic acid. The binding site differs in both architecture and mode of recognition from the binding sites of other viruses. LPyV only binds linear carbohydrates that are able to penetrate into the binding slot.
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Affiliation(s)
- Ursula Neu
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Zaigham Mahmood Khan
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Benjamin Schuch
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
| | - Angelina S. Palma
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Yan Liu
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Michael Pawlita
- Department of Genome Modificati and Carcinogenesis (F020), German Cancer Research Center, Heidelberg, Germany
| | - Ten Feizi
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London, United Kingdom
| | - Thilo Stehle
- Interfaculty Institute of Biochemistry, University of Tuebingen, Tuebingen, Germany
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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32
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Cowper B, Matthews S, Tomley F. The molecular basis for the distinct host and tissue tropisms of coccidian parasites. Mol Biochem Parasitol 2012; 186:1-10. [DOI: 10.1016/j.molbiopara.2012.08.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/29/2012] [Accepted: 08/29/2012] [Indexed: 01/20/2023]
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33
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Salehi N, Peng CA. Gene transfection of Toxoplasma gondii using PEI/DNA polyplexes. J Microbiol Methods 2012; 91:133-7. [DOI: 10.1016/j.mimet.2012.08.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 07/31/2012] [Accepted: 08/02/2012] [Indexed: 11/25/2022]
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Abstract
INTRODUCTION Toxoplasma gondii, the agent that causes toxoplasmosis, is an opportunistic parasite that infects many mammalian species. It is an obligate intracellular parasite that causes severe congenital neurological and ocular disease mostly in immunocompromised humans. The current regimen of therapy includes only a few medications that often lead to hypersensitivity and toxicity. In addition, there are no vaccines available to prevent the transmission of this agent. Therefore, safer and more effective medicines to treat toxoplasmosis are urgently needed. AREAS COVERED The author presents in silico and in vitro strategies that are currently used to screen for novel targets and unique chemotypes against T. gondii. Furthermore, this review highlights the screening technologies and characterization of some novel targets and new chemical entities that could be developed into highly efficacious treatments for toxoplasmosis. EXPERT OPINION A number of diverse methods are being used to design inhibitors against T. gondii. These include ligand-based methods, in which drugs that have been shown to be efficacious against other Apicomplexa parasites can be repurposed to identify lead molecules against T. gondii. In addition, structure-based methods use currently available repertoire of structural information in various databases to rationally design small-molecule inhibitors of T. gondii. Whereas the screening methods have their advantages and limitations, a combination of methods is ideally suited to design small-molecule inhibitors of complex parasites such as T. gondii.
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Affiliation(s)
- Sandhya Kortagere
- Drexel University College of Medicine, Institute for Molecular Medicine, Department of Microbiology and Immunology, 2900, Queen Lane, PA 19129, USA.
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35
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Saouros S, Dou Z, Henry M, Marchant J, Carruthers VB, Matthews S. Microneme protein 5 regulates the activity of Toxoplasma subtilisin 1 by mimicking a subtilisin prodomain. J Biol Chem 2012; 287:36029-40. [PMID: 22896704 DOI: 10.1074/jbc.m112.389825] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Toxoplasma gondii is the model parasite of the phylum Apicomplexa, which contains obligate intracellular parasites of medical and veterinary importance. Apicomplexans invade host cells by a multistep process involving the secretion of adhesive microneme protein (MIC) complexes. The subtilisin protease TgSUB1 trims several MICs on the parasite surface to activate gliding motility and host invasion. Although a previous study showed that expression of the secretory protein TgMIC5 suppresses TgSUB1 activity, the mechanism was unknown. Here, we solve the three-dimensional structure of TgMIC5 by nuclear magnetic resonance (NMR), revealing that it mimics a subtilisin prodomain including a flexible C-terminal peptide that may insert into the subtilisin active site. We show that TgMIC5 is an almost 50-fold more potent inhibitor of TgSUB1 activity than the small molecule inhibitor N-[N-(N-acetyl-L-leucyl)-L-leucyl]-L-norleucine (ALLN). Moreover, we demonstrate that TgMIC5 is retained on the parasite plasma membrane via its physical interaction with the membrane-anchored TgSUB1.
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Affiliation(s)
- Savvas Saouros
- Division of Molecular Biosciences, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom
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