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Widdicombe M, Coff L, Nowak BF, Ramsland PA, Bott NJ. Understanding the host response of farmed fish to blood flukes (Trematoda: Aporocotylidae) for developing new treatment strategies. FISH & SHELLFISH IMMUNOLOGY 2024; 149:109613. [PMID: 38710341 DOI: 10.1016/j.fsi.2024.109613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/08/2024]
Abstract
Aporocotylids (Trematoda: Digenea), also known as fish blood flukes infect the circulatory system of fish leading to serious health problems and mortality. Aporocotylids are a particular concern for farmed fish as infection intensity can increase within the farming environment and lead to mortalities. In the context of managing these infections, one of the most crucial aspects to consider is the host response of the infected fish against these blood flukes. Understanding the response is essential to improving current treatment strategies that are largely based on the use of anthelmintic praziquantel to manage infections in aquaculture. This review focuses on the current knowledge of farmed fish host responses against the different life stages of aporocotylids. New treatment strategies that are able to provide protection against reinfections should be a long-term goal and is not possible without understanding the fish response to infection and the interactions between host and parasite.
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Affiliation(s)
- Maree Widdicombe
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia
| | - Lachlan Coff
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Australian Centre for Disease Preparedness, CSIRO, East Geelong, Victoria, 3219, Australia
| | - Barbara F Nowak
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Institute for Marine and Antarctic Studies, University of Tasmania, Locked Bag 1370, Launceston, Tasmania, 7250, Australia
| | - Paul A Ramsland
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia; Department of Immunology, Monash University, Melbourne, Victoria, 3004. Australia; Department of Surgery, Austin Health, University of Melbourne, Heidelberg, Victoria, 3084, Australia
| | - Nathan J Bott
- School of Science, STEM College, RMIT University, Bundoora, Victoria, 3083, Australia.
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2
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Kim J, Sohn WM, Bae YA. Prostaglandin synthase activity of sigma- and mu-class glutathione transferases in a parasitic trematode, Clonorchis sinensis. PARASITES, HOSTS AND DISEASES 2024; 62:205-216. [PMID: 38835261 DOI: 10.3347/phd.24004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 03/21/2024] [Indexed: 06/06/2024]
Abstract
Sigma-class glutathione transferase (GST) proteins with dual GST and prostaglandin synthase (PGS) activities play a crucial role in the establishment of Clonorchis sinensis infection. Herein, we analyzed the structural and enzymatic properties of sigma-class GST (CsGST-σ) proteins to obtain insight into their antioxidant and immunomodulatory functions in comparison with mu-class GST (CsGST-μ) proteins. CsGST-σ proteins conserved characteristic structures, which had been described in mammalian hematopoietic prostaglandin D2 synthases. Recombinant forms of these CsGST-σ and CsGST-μ proteins expressed in Escherichia coli exhibited considerable degrees of GST and PGS activities with substantially different specific activities. All recombinant proteins displayed higher affinities toward prostaglandin H2 (PGS substrate; average Km of 30.7 and 3.0 μm for prostaglandin D2 [PGDS] and E2 synthase [PGES], respectively) than those toward CDNB (GST substrate; average Km of 1,205.1 μm). Furthermore, the catalytic efficiency (Kcat/Km) of the PGDS/PGES activity was higher than that of GST activity (average Kcat/Km of 3.1, 0.7, and 7.0×10-3 s-1μm-1 for PGDS, PGES, and GST, respectively). Our data strongly suggest that the C. sinensis sigma- and mu-class GST proteins are deeply involved in regulating host immune responses by generating PGD2 and PGE2 in addition to their roles in general detoxification.
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Affiliation(s)
- Jiyoung Kim
- Department of Microbiology and Diabetes Institute, Gachon University College of Medicine, Incheon 21999, Korea
| | - Woon-Mok Sohn
- Department of Parasitology and Tropical Medicine, and Institute of Health Sciences, Gyeongsang National University College of Medicine, Jinju 52727, Korea
| | - Young-An Bae
- Department of Microbiology and Diabetes Institute, Gachon University College of Medicine, Incheon 21999, Korea
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University College of Medicine, Incheon 21999, Korea
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3
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Sánchez Pérez LDC, Zubillaga RA, García-Gutiérrez P, Landa A. Sigma-Class Glutathione Transferases (GSTσ): A New Target with Potential for Helminth Control. Trop Med Infect Dis 2024; 9:85. [PMID: 38668546 PMCID: PMC11053550 DOI: 10.3390/tropicalmed9040085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 04/10/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024] Open
Abstract
Glutathione transferases (GSTs EC 2.5.1.18) are critical components of phase II metabolism, instrumental in xenobiotics' metabolism. Their primary function involves conjugating glutathione to both endogenous and exogenous toxic compounds, which increases their solubility and enables their ejection from cells. They also play a role in the transport of non-substrate compounds and immunomodulation, aiding in parasite establishment within its host. The cytosolic GST subfamily is the most abundant and diverse in helminths, and sigma-class GST (GSTσ) belongs to it. This review focuses on three key functions of GSTσ: serving as a detoxifying agent that provides drug resistance, functioning as an immune system modulator through its involvement in prostaglandins synthesis, and acting as a vaccine antigen.
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Affiliation(s)
| | - Rafael A. Zubillaga
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City C.P. 09310, Mexico; (L.d.C.S.P.); (P.G.-G.)
| | - Ponciano García-Gutiérrez
- Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City C.P. 09310, Mexico; (L.d.C.S.P.); (P.G.-G.)
| | - Abraham Landa
- Departamento de Microbiología y Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico City C.P. 04510, Mexico
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Rangubpit W, Suwan E, Sangthong D, Wongpanit K, Stich RW, Pongprayoon P, Jittapalapong S. Elucidating structure and dynamics of glutathione S-transferase from Rhipicephalus (Boophilus) microplus. J Biomol Struct Dyn 2023; 41:7309-7317. [PMID: 36093982 DOI: 10.1080/07391102.2022.2120079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 08/26/2022] [Indexed: 10/14/2022]
Abstract
Rhipicephalus (Boophilus) microplus is tick parasite that affects the cattle industry worldwide. In R. (B.) microplus, acaricide resistance develops rapidly against many commercial acaricides. One of main resistance strategies is to enhance the metabolic detoxification mediated by R. (B.) microplus glutathione-S-transferase (RmGST). RmGST detoxifies acaricides by catalyzing the conjugation of glutathione to acaricides. Although structural and dynamic details of RmGST are expected to elucidate the biologic activity of this molecule, these data have not been available to date. Thus, Molecular Dynamics simulations were employed to study ligand-free RmGST at an atomic level. Like other m-class GSTs, the flexible m loop (m1) of RmGST was observed. M1 seems to shield the active sites from the bulk. A RmGST dimer is stabilized by the lock-and-key motif (F57 as "key") and hydrogen bonds of R82-E91 and R82-D98 at the dimer interface. Without substrates, conserved catalytic Y116 and N209 can interact with V112, G210 (for Y116) and F215 (for N209). Overall, most residues involving in RmGST function and stability are similar to other m-class GSTs. This implies similar structural stability and catalytic activity of RmGST to other GSTs. An insight obtained here will be useful for management of acaricide resistance and tick control.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Warin Rangubpit
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
- Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
| | - Eukote Suwan
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
| | - Danai Sangthong
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
| | - Kannika Wongpanit
- Department of Agriculture and Resources, Faculty of Natural Resources and Agro-Industry, Chalermphrakiat Sakon Nakhon Province Campus, Kasetsart University, Sakon Nakhon, Thailand
| | - Roger W Stich
- Department of Veterinary Pathobiology, University of Missouri, Columbia, MO, USA
| | - Prapasiri Pongprayoon
- Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok, Thailand
- Center for Advanced Studies in Nanotechnology for Chemical, Food and Agricultural Industries, KU Institute for Advanced Studies, Kasetsart University, Bangkok, Thailand
| | - Sathaporn Jittapalapong
- Department of Veterinary Technology, Faculty of Veterinary Technology, Kasetsart University, Bangkok, Thailand
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Piao X, Duan J, Jiang N, Liu S, Hou N, Chen Q. Schistosoma japonicum Tyrosine Hydroxylase is promising targets for immunodiagnosis and immunoprotection of Schistosomiasis japonica. PLoS Negl Trop Dis 2023; 17:e0011389. [PMID: 37276235 DOI: 10.1371/journal.pntd.0011389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/18/2023] [Indexed: 06/07/2023] Open
Abstract
Identification of promising schistosome antigen targets is crucial for the development of anti-schistosomal strategies. Schistosomes rely on their neuromuscular systems to coordinate important locomotory behaviors. Tyrosine hydroxylase (TH) is critical in the initial rate-limiting step in biosynthesis of catecholamine, the important neuroactive agents, which promote the lengthening of the worm through muscular relaxation and are therefore of great importance to the movement of the organism both within and between its hosts. THs from both Schistosoma mansoni and Schistosoma japonicum and their enzyme activities have been discovered; however, the role of these proteins during infection have not been explored. Herein, a recombinant protein of the nonconserved fragment of S. japonicum TH (SjTH) was produced and the corresponding polyclonal antibody was generated. The expression and antigenicity of SjTH were detected by qRT-PCR, western blotting, immunofluorescence assays, and ELISA. Mice immunized with the recombinant SjTH were challenged with cercariae to evaluate the immunoprotective value of this protein. Our results showed SjTH not only distributed in the head associated with the central nervous system, but also expressed along the tegument and the intestinal intima, which are involved in the movement, coupling and digestion of the parasites and associated with the peripheral nervous system. This protein can effectively stimulate humoral immune responses in mammalian hosts and has high potential as a biomarker for schistosomiasis immunodiagnosis. Furthermore, immunization with recombinant SjTH showed to reduce the worm and egg burden of challenged mice, and to contribute to the systemic balance of the Th1/Th2 responses. Taken together, these results suggest that SjTH is an important pathogenic molecule in S. japonicum and may be a possible target for anti-schistosomal approaches.
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Affiliation(s)
- Xianyu Piao
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Jiamei Duan
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ning Jiang
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, Shenyang, China
| | - Shuai Liu
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Nan Hou
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Qijun Chen
- NHC Key Laboratory of Systems Biology of Pathogens, Institute of Pathogen Biology, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
- Key Laboratory of Livestock Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Ruminant Infectious Disease Prevention and Control (East), Ministry of Agriculture and Rural Affairs, College of Animal Science and Veterinary Medicine, Shenyang Agricultural University, Shenyang, China
- The Research Unit for Pathogenic Mechanisms of Zoonotic Parasites, Chinese Academy of Medical Sciences, Shenyang, China
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Valli A, Achilonu I. Molecular dynamics-derived pharmacophores of Schistosoma glutathione transferase in complex with bromosulfophthalein: Screening and analysis of potential inhibitors. J Mol Graph Model 2023; 122:108457. [PMID: 37004419 DOI: 10.1016/j.jmgm.2023.108457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/27/2023] [Accepted: 03/16/2023] [Indexed: 03/28/2023]
Abstract
Schistosoma glutathione transferases (GSTs) have been identified as attractive drug targets for the design of novel antischistosomals. Here, we used in silico methods to validate the discriminative inhibitory properties of bromosulfophthalein (BSP) against the 26-kDa GST from S. japonicum (Sj26GST), and the 28-kDa GST from S. haematobium (Sh28GST), versus human GST (hGST) isoforms alpha (hGSTA), mu (hGSTM) and pi (hGSTP). The use of BSP as an archetypal selective inhibitor was harnessed to produce molecular dynamics-derived pharmacophores of the two targets. Pharmacophore-based screening using a large dataset of experimental and approved drug compounds was performed to produce a shortlist of candidates. The top candidate for each target was prioritised via molecular docking, yielding guanosine-3'-monophosphate-5'-diphosphate (G3D) for Sj26GST, and quercetin-3'-O-phosphate (Q3P) for Sh28GST. Comparative molecular dynamics studies of both candidates compared to BSP showed similar characteristics of binding stability and strength, suggesting their potential to emulate the inhibitory effects of BSP.
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Affiliation(s)
- Akeel Valli
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, 2050, South Africa
| | - Ikechukwu Achilonu
- Protein Structure-Function Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Johannesburg, 2050, South Africa.
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7
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Mordvinov V, Pakharukova M. Xenobiotic-Metabolizing Enzymes in Trematodes. Biomedicines 2022; 10:biomedicines10123039. [PMID: 36551794 PMCID: PMC9775572 DOI: 10.3390/biomedicines10123039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/21/2022] [Accepted: 11/22/2022] [Indexed: 11/26/2022] Open
Abstract
Trematode infections occur worldwide causing considerable deterioration of human health and placing a substantial financial burden on the livestock industry. The hundreds of millions of people afflicted with trematode infections rely entirely on only two drugs (praziquantel and triclabendazole) for treatment. An understanding of anthelmintic biotransformation pathways in parasites should clarify factors that can modulate therapeutic potency of anthelmintics currently in use and may lead to the discovery of synergistic compounds for combination treatments. Despite the pronounced epidemiological significance of trematodes, there is still no adequate understanding of the functionality of their metabolic systems, including xenobiotic-metabolizing enzymes. The review is focused on the structure and functional significance of the xenobiotic-metabolizing system in trematodes. Knowledge in this field can solve practical problems related to the search for new targets for antiparasitic therapy based on a focused action on certain elements of the parasite's metabolic system. Knowledge of the functionality of this system is required to understand the adaptation of the biochemical processes of parasites residing in the host and mechanisms of drug resistance development, as well as to select a promising molecular target for the discovery and development of new anthelmintic drugs.
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Affiliation(s)
- Viatcheslav Mordvinov
- Laboratory of Molecular Mechanisms of Pathological Processes, Institute of Cytology and Genetics SB RAS, 10 Akad. Lavrentiev Ave., Novosibirsk 630090, Russia
| | - Maria Pakharukova
- Laboratory of Molecular Mechanisms of Pathological Processes, Institute of Cytology and Genetics SB RAS, 10 Akad. Lavrentiev Ave., Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogov Str., Novosibirsk 630090, Russia
- Correspondence: ; Tel.: +7-(913)-394-6669
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Pooe K, Thulo M, Makumbe H, Akumadu B, Otun O, Aloke C, Achilonu I. Biophysical description of Bromosulfophthalein interaction with the 28-kDa glutathione transferase from Schistosoma japonicum. Mol Biochem Parasitol 2022; 252:111524. [PMID: 36195242 DOI: 10.1016/j.molbiopara.2022.111524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 09/12/2022] [Accepted: 09/29/2022] [Indexed: 12/31/2022]
Abstract
Glutathione transferases (GSTs) are major detoxification enzymes vital for the survival and reproduction of schistosomes during infection in humans. Schistosoma encode two GST isoenzymes, the 26- and 28-kDa isoforms, that show different substrate specificities and cellular localisations. Bromosulfophthalein (BSP) has been identified and characterised as a potent 26-kDa Schistosoma japonicum GST (Sj26GST) inhibitor with an anthelmintic potential. This study describes the structure, function, and ligandin properties of the 28-kDa Schistosoma japonicum GST (Sj28GST) towards BSP. Enzyme kinetics show that BSP is a potent enzyme inhibitor, with a specific activity decreases from 60.4 µmol/min/mg to 0.0742 µmol/min/mg and an IC50 in the micromolar range of 0.74 µM. Far-UV circular dichroism confirmed that purified Sj28GST follows a typical GST fold, which is predominantly alpha-helical. Fluorescence spectroscopy suggests that BSP binding occurs at a site distinct from the glutathione-binding site (G-site); however, the binding does not alter the local G-site environment. Isothermal titration calorimetry studies show that the binding of BSP to Sj28GST is exergonic (∆G°= -33 kJ/mol) and enthalpically-driven, with a stoichiometry of one BSP per dimer. The stability of Sj28GST (∆G(H2O) = 4.7 kcal/mol) is notably lower than Sj26GST, owing to differences in the enzyme's dimeric interfaces. We conclude that Sj28GST shares similar biophysical characteristics with Sj26GST based on its kinetic properties and susceptibility to low concentrations of BSP. The study supports the potential benefits of re-purposing BSP as a potential drug or prodrug to mitigate the scourge of schistosomiasis.
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Affiliation(s)
- Kagiso Pooe
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Monare Thulo
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Hattie Makumbe
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Blessing Akumadu
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Oluwatobin Otun
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Chinyere Aloke
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa
| | - Ikechukwu Achilonu
- Protein Structure-Function and Research Unit, School of Molecular and Cell Biology, Faculty of Science, University of the Witwatersrand, Braamfontein 2050, Johannesburg, South Africa.
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9
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Draft genome of the bluefin tuna blood fluke, Cardicola forsteri. PLoS One 2022; 17:e0276287. [PMID: 36240154 PMCID: PMC9565688 DOI: 10.1371/journal.pone.0276287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 10/03/2022] [Indexed: 11/12/2022] Open
Abstract
The blood fluke Cardicola forsteri (Trematoda: Aporocotylidae) is a pathogen of ranched bluefin tuna in Japan and Australia. Genomics of Cardicola spp. have thus far been limited to molecular phylogenetics of select gene sequences. In this study, sequencing of the C. forsteri genome was performed using Illumina short-read and Oxford Nanopore long-read technologies. The sequences were assembled de novo using a hybrid of short and long reads, which produced a high-quality contig-level assembly (N50 > 430 kb and L50 = 138). The assembly was also relatively complete and unfragmented, comprising 66% and 7.2% complete and fragmented metazoan Benchmarking Universal Single-Copy Orthologs (BUSCOs), respectively. A large portion (> 55%) of the genome was made up of intergenic repetitive elements, primarily long interspersed nuclear elements (LINEs), while protein-coding regions cover > 6%. Gene prediction identified 8,564 hypothetical polypeptides, > 77% of which are homologous to published sequences of other species. The identification of select putative proteins, including cathepsins, calpains, tetraspanins, and glycosyltransferases is discussed. This is the first genome assembly of any aporocotylid, a major step toward understanding of the biology of this family of fish blood flukes and their interactions within hosts.
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10
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Valli A, Achilonu I. Comparative structural analysis of the human and
Schistosoma
glutathione transferase dimer interface using selective binding of bromosulfophthalein. Proteins 2022; 90:1561-1569. [DOI: 10.1002/prot.26338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/05/2022] [Accepted: 03/14/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Akeel Valli
- Protein Structure‐Function Research Unit, School of Molecular and Cell Biology, Faculty of Science University of the Witwatersrand Johannesburg South Africa
| | - Ikechukwu Achilonu
- Protein Structure‐Function Research Unit, School of Molecular and Cell Biology, Faculty of Science University of the Witwatersrand Johannesburg South Africa
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11
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Mtemeli FL, Shoko R, Ndlovu J, Mugumbate G. In Silico Study of Cucurbita maxima Compounds as Potential Therapeutics Against Schistosomiasis. Bioinform Biol Insights 2022; 16:11779322221100741. [PMID: 35615403 PMCID: PMC9125113 DOI: 10.1177/11779322221100741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 04/21/2022] [Indexed: 11/15/2022] Open
Abstract
Schistosomiasis, a disease usually related to poverty and poor sanitation, affects more than 200 million people worldwide. Since the 1970s, the medical sector has depended on a single drug, praziquantel, for the treatment of the disease. The emerging evidence of resistance of the Schistosoma parasite to praziquantel and the drug’s inefficacy against juvenile stages of the parasite makes the need to find alternative drugs an urgent matter. In this study, we explored the inhibition potential of compounds from Cucurbita maxima using molecular docking studies on Schistosoma mansoni purine nucleoside phosphorylase ( SmPNP) and Schistosoma haematobium 28-kDa glutathione S-transferase ( Sh28kDaGST). Following molecular docking studies and analysis of the active sites, the primary amino acids that were observed and shown to be involved in the SmPNP-ligand interaction are CYS 33, ARG 86, HIS 88, TYR 90, ALA 118, ALA 119, PRO 200, TYR 202, GLU 203, VAL 219, MET 221, THR 244, ASN 245, PRO 257 and HIS 259. For the Sh28dKa-ligand interaction, the primary amino acids were PHE 11, ARG 16, TRP 41, LEU 53, GLU 70 and SER 71. Momordicoside I aglycone binds to SmPNP with the lowest binding affinity of -7.9 kcal/mol by pi sigma bond interactions with HIS 88. Balsaminoside B binds to Sh28kDaGST with a binding affinity of −7.6 kcal/mol by hydrogen bond interaction with TRP 41, LEU 53 and SER 71. Pharmacokinetic studies showed favourable drug-like properties for the 10 compounds that exhibited the lowest binding energies. Therefore, we propose that bioactive compounds from C. maxima be considered as potential novel drug hits in the treatment of schistosomiasis.
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Affiliation(s)
- Floryn Lynorah Mtemeli
- Department of Biology, School of Natural Sciences and Mathematics, Chinhoyi University of Technology, Chinhoyi, Zimbabwe
| | - Ryman Shoko
- Department of Biology, School of Natural Sciences and Mathematics, Chinhoyi University of Technology, Chinhoyi, Zimbabwe
| | - Joice Ndlovu
- Department of Biology, School of Natural Sciences and Mathematics, Chinhoyi University of Technology, Chinhoyi, Zimbabwe
| | - Grace Mugumbate
- Department of Chemical Technology, Midlands State University, Gweru, Zimbabwe
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12
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Bedart C, Renault N, Chavatte P, Porcherie A, Lachgar A, Capron M, Farce A. SINAPs: A Software Tool for Analysis and Visualization of Interaction Networks of Molecular Dynamics Simulations. J Chem Inf Model 2022; 62:1425-1436. [PMID: 35239339 PMCID: PMC8966674 DOI: 10.1021/acs.jcim.1c00854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As long as the structural study of molecular mechanisms requires multiple molecular dynamics reflecting contrasted bioactive states, the subsequent analysis of molecular interaction networks remains a bottleneck to be fairly treated and requires a user-friendly 3D view of key interactions. Structural Interaction Network Analysis Protocols (SINAPs) is a proprietary python tool developed to (i) quickly solve key interactions able to distinguish two protein states, either from two sets of molecular dynamics simulations or from two crystallographic structures, and (ii) render a user-friendly 3D view of these key interactions through a plugin of UCSF Chimera, one of the most popular open-source viewing software for biomolecular systems. Through two case studies, glucose transporter-1 (GLUT-1) and A2A adenosine receptor (A2AR), SINAPs easily pinpointed key interactions observed experimentally and relevant for their bioactivities. This very effective tool was thus applied to identify the amino acids involved in the molecular enzymatic mechanisms ruling the activation of an immunomodulator drug candidate, P28 glutathione-S-transferase (P28GST). SINAPs is freely available at https://github.com/ParImmune/SINAPs.
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Affiliation(s)
- Corentin Bedart
- Univ.
Lille, Inserm, CHU Lille, U1286 - Infinite - Institute for Translational
Research in Inflammation, F-59000 Lille, France,Par’Immune,
Bio-incubateur Eurasanté, 70 rue du Dr. Yersin, 59120 Loos-Lez-Lille, France,
| | - Nicolas Renault
- Univ.
Lille, Inserm, CHU Lille, U1286 - Infinite - Institute for Translational
Research in Inflammation, F-59000 Lille, France
| | - Philippe Chavatte
- Univ.
Lille, Inserm, CHU Lille, U1286 - Infinite - Institute for Translational
Research in Inflammation, F-59000 Lille, France
| | - Adeline Porcherie
- Par’Immune,
Bio-incubateur Eurasanté, 70 rue du Dr. Yersin, 59120 Loos-Lez-Lille, France
| | - Abderrahim Lachgar
- Par’Immune,
Bio-incubateur Eurasanté, 70 rue du Dr. Yersin, 59120 Loos-Lez-Lille, France
| | - Monique Capron
- Univ.
Lille, Inserm, CHU Lille, U1286 - Infinite - Institute for Translational
Research in Inflammation, F-59000 Lille, France,Par’Immune,
Bio-incubateur Eurasanté, 70 rue du Dr. Yersin, 59120 Loos-Lez-Lille, France
| | - Amaury Farce
- Univ.
Lille, Inserm, CHU Lille, U1286 - Infinite - Institute for Translational
Research in Inflammation, F-59000 Lille, France,
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13
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Panzner U, Excler JL, Kim JH, Marks F, Carter D, Siddiqui AA. Recent Advances and Methodological Considerations on Vaccine Candidates for Human Schistosomiasis. FRONTIERS IN TROPICAL DISEASES 2021. [DOI: 10.3389/fitd.2021.719369] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Schistosomiasis remains a neglected tropical disease of major public health concern with high levels of morbidity in various parts of the world. Although considerable efforts in implementing mass drug administration programs utilizing praziquantel have been deployed, schistosomiasis is still not contained. A vaccine may therefore be an essential part of multifaceted prevention control efforts. In the 1990s, a joint United Nations committee promoting parasite vaccines shortlisted promising candidates including for schistosomiasis discussed below. After examining the complexity of immune responses in human hosts infected with schistosomes, we review and discuss the antigen design and preclinical and clinical development of the four leading vaccine candidates: Sm-TSP-2 in Phase 1b/2b, Sm14 in Phase 2a/2b, Sm-p80 in Phase 1 preparation, and Sh28GST in Phase 3. Our assessment of currently leading vaccine candidates revealed some methodological issues that preclude a fair comparison between candidates and the rationale to advance in clinical development. These include (1) variability in animal models - in particular non-human primate studies - and predictive values of each for protection in humans; (2) lack of consensus on the assessment of parasitological and immunological parameters; (3) absence of reliable surrogate markers of protection; (4) lack of well-designed parasitological and immunological natural history studies in the context of mass drug administration with praziquantel. The controlled human infection model - while promising and unique - requires validation against efficacy outcomes in endemic settings. Further research is also needed on the impact of advanced adjuvants targeting specific parts of the innate immune system that may induce potent, protective and durable immune responses with the ultimate goal of achieving meaningful worm reduction.
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Panzner U, Boissier J. Natural Intra- and Interclade Human Hybrid Schistosomes in Africa with Considerations on Prevention through Vaccination. Microorganisms 2021; 9:microorganisms9071465. [PMID: 34361901 PMCID: PMC8305539 DOI: 10.3390/microorganisms9071465] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/05/2021] [Accepted: 07/06/2021] [Indexed: 12/04/2022] Open
Abstract
Causal agents of schistosomiasis are dioecious, digenean schistosomes affecting mankind in 76 countries. Preventive measures are manifold but need to be complemented by vaccination for long-term protection; vaccine candidates in advanced pre-clinical/clinical stages include Sm14, Sm-TSP-2/Sm-TSP-2Al®, Smp80/SchistoShield®, and Sh28GST/Bilhvax®. Natural and anthropogenic changes impact on breaking species isolation barriers favoring introgressive hybridization, i.e., allelic exchange among gene pools of sympatric, interbreeding species leading to instant large genetic diversity. Phylogenetic distance matters, thus the less species differ phylogenetically the more likely they hybridize. PubMed and Embase databases were searched for publications limited to hybridale confirmation by mitochondrial cytochrome c oxidase (COX) and/or nuclear ribosomal internal transcribed spacer (ITS). Human schistosomal hybrids are predominantly reported from West Africa with clustering in the Senegal River Basin, and scattering to Europe, Central and Eastern Africa. Noteworthy is the dominance of Schistosoma haematobium interbreeding with human and veterinary species leading due to hybrid vigor to extinction and homogenization as seen for S. guineensis in Cameroon and S. haematobium in Niger, respectively. Heterosis seems to advantage S. haematobium/S. bovis interbreeds with dominant S. haematobium-ITS/S. bovis-COX1 profile to spread from West to East Africa and reoccur in France. S. haematobium/S. mansoni interactions seen among Senegalese and Côte d’Ivoirian children are unexpected due to their high phylogenetic distance. Detecting pure S. bovis and S. bovis/S. curassoni crosses capable of infecting humans observed in Corsica and Côte d’Ivoire, and Niger, respectively, is worrisome. Taken together, species hybridization urges control and preventive measures targeting human and veterinary sectors in line with the One-Health concept to be complemented by vaccination protecting against transmission, infection, and disease recurrence. Functional and structural diversity of naturally occurring human schistosomal hybrids may impact current vaccine candidates requiring further research including natural history studies in endemic areas targeted for clinical trials.
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Affiliation(s)
- Ursula Panzner
- Division of Infectious Diseases and Tropical Medicine, Ludwig Maximilian University of Munich, 80539 Munich, Germany
- Swiss Tropical and Public Health Institute, University of Basel, 4002 Basel, Switzerland
- Correspondence: ; Tel.: +49-176-6657-2910
| | - Jerome Boissier
- IHPE, University of Montpellier, CNRS, Ifremer, University of Perpignan, 66860 Perpignan, France;
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15
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Al-Naseri A, Al-Absi S, El Ridi R, Mahana N. A comprehensive and critical overview of schistosomiasis vaccine candidates. J Parasit Dis 2021; 45:557-580. [PMID: 33935395 PMCID: PMC8068781 DOI: 10.1007/s12639-021-01387-w] [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: 01/16/2021] [Accepted: 03/31/2021] [Indexed: 12/11/2022] Open
Abstract
A digenetic platyhelminth Schistosoma is the causative agent of schistosomiasis, one of the neglected tropical diseases that affect humans and animals in numerous countries in the Middle East, sub-Saharan Africa, South America and China. Several control methods were used for prevention of infection or treatment of acute and chronic disease. Mass drug administration led to reduction in heavy-intensity infections and morbidity, but failed to decrease schistosomiasis prevalence and eliminate transmission, indicating the need to develop anti-schistosome vaccine to prevent infection and parasite transmission. This review summarizes the efficacy and protective capacity of available schistosomiasis vaccine candidates with some insights and future prospects.
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Affiliation(s)
- Aya Al-Naseri
- Zoology Department, Faculty of Science, Cairo Univesity, Giza, 12613 Egypt
| | - Samar Al-Absi
- Zoology Department, Faculty of Science, Cairo Univesity, Giza, 12613 Egypt
| | - Rashika El Ridi
- Zoology Department, Faculty of Science, Cairo Univesity, Giza, 12613 Egypt
| | - Noha Mahana
- Zoology Department, Faculty of Science, Cairo Univesity, Giza, 12613 Egypt
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16
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Molehin AJ. Schistosomiasis vaccine development: update on human clinical trials. J Biomed Sci 2020; 27:28. [PMID: 31969170 PMCID: PMC6977295 DOI: 10.1186/s12929-020-0621-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Accepted: 01/16/2020] [Indexed: 01/13/2023] Open
Abstract
Schistosomiasis causes significant levels of morbidity and mortality in many geographical regions of the world. The disease is caused by infections with parasitic blood flukes known as schistosomes. The control of schistosomiasis over the last several decades has been centered on the mass drug administration (MDA) of praziquantel (PZQ), which is the only drug currently available for treatment. Despite the concerted efforts of MDA programs, the prevalence and transmission of schistosomiasis has remained largely unchecked due to the fact that PZQ is ineffective against juvenile schistosomes, does not prevent re-infection and the emergence of PZQ-resistant parasites. In addition, other measures such as the water, sanitation and hygiene programs and snail intermediate hosts control have had little to no impact. These drawbacks indicate that the current control strategies are severely inadequate at interrupting transmission and therefore, implementation of other control strategies are required. Ideally, an efficient vaccine is what is needed for long term protection thereby eliminating the current efforts of repeated mass drug administration. However, the general consensus in the field is that the integration of a viable vaccine with MDA and other control measures offer the best chance of achieving the goal of schistosomiasis elimination. This review focuses on the present status of schistosomiasis vaccine candidates in different phases of human clinical trials and provide some insight into future vaccine discovery and design.
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Affiliation(s)
- Adebayo J Molehin
- Center for Tropical Medicine and Infectious Diseases, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, USA. .,Department of Internal Medicine, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, USA.
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17
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Line K, Isupov MN, LaCourse EJ, Cutress DJ, Morphew RM, Brophy PM, Littlechild JA. X-ray structure of Fasciola hepatica Sigma class glutathione transferase 1 reveals a disulfide bond to support stability in gastro-intestinal environment. Sci Rep 2019; 9:902. [PMID: 30696975 PMCID: PMC6351632 DOI: 10.1038/s41598-018-37531-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 12/05/2018] [Indexed: 11/18/2022] Open
Abstract
Sigma class GST (Prostaglandin D synthase), FhGST-S1, is present in the excretory–secretory products (ES) of the liver fluke parasite Fasciola hepatica as cargo of extracellular vesicles (EVs) released by the parasite. FhGST-S1 has a well characterised role in the modulation of the immune response; a key fluke intercession that allows for establishment and development within their hosts. We have resolved the three-dimensional structure of FhGST-S1 in complex with its co-factor glutathione, in complex with a glutathione-cysteine adduct, and in a glutathione disulfide complex in order to initiate a research pipeline to mechanistically understand how FhGST-S1 functions within the host environment and to rationally design selective inhibitors. The overall fold of FhGST-S1 shows high structural similarity to other Sigma class GSTs. However, a unique interdomain disulfide bond was found in the FhGST-S1 which could stabilise the structure within the host gastro-intestinal environment. The position of the two domains of the protein with respect to each other is seen to be crucial in the formation of the active site cleft of the enzyme. The interdomain disulfide bond raises the possibility of oxidative regulation of the active site of this GST protein.
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Affiliation(s)
- Kirsty Line
- Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Michail N Isupov
- Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - E James LaCourse
- Liverpool School of Tropical Medicine, Liverpool, Pembroke Place, L3 5QA, UK
| | - David J Cutress
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, SY23 3DA, UK
| | - Russell M Morphew
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, SY23 3DA, UK
| | - Peter M Brophy
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, SY23 3DA, UK.
| | - Jennifer A Littlechild
- Henry Wellcome Building for Biocatalysis, Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
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18
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Sarazin A, Dendooven A, Delbeke M, Gatault S, Pagny A, Standaert A, Rousseaux C, Desreumaux P, Dubuquoy L, Capron M. Treatment with P28GST, a schistosome-derived enzyme, after acute colitis induction in mice: Decrease of intestinal inflammation associated with a down regulation of Th1/Th17 responses. PLoS One 2018; 13:e0209681. [PMID: 30592734 PMCID: PMC6310452 DOI: 10.1371/journal.pone.0209681] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/10/2018] [Indexed: 12/22/2022] Open
Abstract
Background P28GST, a 28Kd glutathione S-transferase enzymatic protein derived from a schistosome helminth prevents experimental colitis when administered subcutaneously in the presence of adjuvant by decreasing pro-inflammatory Th1/Th17 response. Given the antioxidant properties of P28GST, we evaluated its anti-inflammatory potential when administered locally after colitis induction in the absence of adjuvant. Methods Colitis was induced in BALB/c mice by rectal administration of TNBS, followed by two intraperitoneal injections of P28GST at day 1 and day 2. Mice were sacrificed 48h after TNBS administration and evaluated for macroscopic and histological scores, myeloperoxidase (MPO) quantification and cytokine messenger RNA expression in the colonic tissues. Results Both clinical and histological scores significantly decreased in mice treated with P28GST at 5 or 50μg/kg when compared to vehicle- treated mice. A significant reduction of MPO was detected in colonic tissues from P28GST–treated mice, similarly to mice treated with methylprednisolone as the reference treatment. Pro-inflammatory cytokines TNF, IL-1β, and IL-6, mRNA as well as serum levels were down-regulated in mice colonic tissues treated with P28GST at 5 or 50μg/kg. In addition, a significant decrease of mRNA expression levels of T-bet, and ROR-γ, respective markers of Th1 and Th17 cells was observed. Whereas no significant effect was detected on Gata3 mRNA, a marker of Th2 cells, the Arg/iNOS mRNA levels significantly increased in P28GST-treated mice, suggesting the induction of M2 macrophages. Conclusions These findings provide evidence that P28GST injected locally after colitis induction induces a potent decrease of colitis inflammation in mice, associated to downregulation of Th1/Th17 response, and induction of anti-inflammatory alternatively activated macrophages.
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Affiliation(s)
- Aurore Sarazin
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Arnaud Dendooven
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Marie Delbeke
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Solène Gatault
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Aurélien Pagny
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Annie Standaert
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | | | - Pierre Desreumaux
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Laurent Dubuquoy
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
| | - Monique Capron
- Univ. Lille, Inserm, CHU Lille, U995 – LIRIC – Lille Inflammation Research International Center, Lille, France
- * E-mail:
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19
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Riveau G, Schacht AM, Dompnier JP, Deplanque D, Seck M, Waucquier N, Senghor S, Delcroix-Genete D, Hermann E, Idris-Khodja N, Levy-Marchal C, Capron M, Capron A. Safety and efficacy of the rSh28GST urinary schistosomiasis vaccine: A phase 3 randomized, controlled trial in Senegalese children. PLoS Negl Trop Dis 2018; 12:e0006968. [PMID: 30532268 PMCID: PMC6300301 DOI: 10.1371/journal.pntd.0006968] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 12/19/2018] [Accepted: 11/05/2018] [Indexed: 01/01/2023] Open
Abstract
Background Urinary schistosomiasis, the result of infection by Schistosoma haematobium (Sh), remains a major global health concern. A schistosome vaccine could represent a breakthrough in schistosomiasis control strategies, which are presently based on treatment with praziquantel (PZQ). We report the safety and efficacy of the vaccine candidate recombinant 28-kDa glutathione S-transferase of Sh (rSh28GST) designated as Bilhvax, in a phase 3 trial conducted in Senegal. Methods and findings After clearance of their ongoing schistosomiasis infection with two doses of PZQ, 250 children aged 6–9 years were randomized to receive three subcutaneous injections of either rSh28GST/Alhydrogel (Bilhvax group) or Alhydrogel alone (control group) at week 0 (W0), W4, and W8 and then a booster at W52 (one year after the first injection). PZQ treatment was given at W44, according to previous phase 2 results. The primary endpoint of the analysis was efficacy, evaluated as a delay of recurrence of urinary schistosomiasis, defined by a microhematuria associated with at least one living Sh egg in urine from baseline to W152. During the 152-week follow-up period, there was no difference between study arms in the incidence of serious adverse events. The median follow-up time for subjects without recurrence was 22.9 months for the Bilhvax group and 18.8 months for the control group (log-rank p = 0.27). At W152, 108 children had experienced at least one recurrence in the Bilhvax group versus 112 in the control group. Specific immunoglobulin (Ig)G1, IgG2, and IgG4, but not IgG3 or IgA titers, were increased in the vaccine group. Conclusions While Bilhvax was immunogenic and well tolerated by infected children, a sufficient efficacy was not reached. The lack of effect may be the result of several factors, including interference by individual PZQ treatments administered each time a child was found infected, or the chosen vaccine-injection regimen favoring blocking IgG4 rather than protective IgG3 antibodies. These observations contrasting with results obtained in experimental models will help in the design of future trials. Trial registration ClinicalTrials.gov NCT 00870649 Vaccines represent an attractive tool in the fight against schistosomiasis. Pre-clinical immunization studies with the schistosome enzyme 28 kDa glutathione S-transferase (28GST) have shown a significant reduction of schistosome egg production and subsequent pathology. The objective of the present phase 3 trial was to assess the efficacy and safety of vaccination with the recombinant 28GST of Schistosoma haematobium (rSh28GST) named Bilhvax, in infected school children. After Praziquantel treatment before inclusion and three administrations of rSh28GST at one month interval as primo-vaccination, subjects received a boost injection one year after the first administration. The efficacy was evaluated as a delay of recurrence of urinary schistosomiasis. While immunological analysis showed that Bilhvax induced a consistent immune response characterized by antibodies able to inhibit 28GST enzymatic activity, the efficacy endpoint was not reached. This lack of significant effect may be due to the negative conjunction of a too challenging recurrence criterion associated with safety measures ensuring repeated PZQ treatment. The control of these main factors will be essential for the subsequent trials and must provide evidence of the Bilhvax efficacy as a safe vaccine against uro-genital schistosomiasis.
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Affiliation(s)
- Gilles Riveau
- Biomedical Research Center EPLS, Saint Louis, Senegal
- CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Univ. Lille, CNRS UMR, Inserm U1019—Lille, France
- * E-mail:
| | - Anne-Marie Schacht
- Biomedical Research Center EPLS, Saint Louis, Senegal
- CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Univ. Lille, CNRS UMR, Inserm U1019—Lille, France
| | | | - Dominique Deplanque
- Univ. Lille, Inserm, CHU Lille, CIC—Centre d’investigation clinique, Lille, France
| | - Modou Seck
- Biomedical Research Center EPLS, Saint Louis, Senegal
| | - Nawal Waucquier
- Univ. Lille, Inserm, CHU Lille, CIC—Centre d’investigation clinique, Lille, France
| | - Simon Senghor
- Biomedical Research Center EPLS, Saint Louis, Senegal
| | - Delphine Delcroix-Genete
- CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Univ. Lille, CNRS UMR, Inserm U1019—Lille, France
| | - Emmanuel Hermann
- CIIL—Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Univ. Lille, CNRS UMR, Inserm U1019—Lille, France
| | | | | | - Monique Capron
- Univ. Lille, Inserm, CHU Lille, LIRIC U 995, Lille Inflammation Research International Center Lille, France
| | - André Capron
- Académie des Sciences, 23 Quai de Conti, Paris, France
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20
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Kalita J, Shukla R, Shukla H, Gadhave K, Giri R, Tripathi T. Comprehensive analysis of the catalytic and structural properties of a mu-class glutathione s-transferase from Fasciola gigantica. Sci Rep 2017; 7:17547. [PMID: 29235505 PMCID: PMC5727538 DOI: 10.1038/s41598-017-17678-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 11/28/2017] [Indexed: 01/12/2023] Open
Abstract
Glutathione S‒transferases (GSTs) play an important role in the detoxification of xenobiotics. They catalyze the nucleophilic addition of glutathione (GSH) to nonpolar compounds, rendering the products water-soluble. In the present study, we investigated the catalytic and structural properties of a mu-class GST from Fasciola gigantica (FgGST1). The purified recombinant FgGST1 formed a homodimer composed of 25 kDa subunit. Kinetic analysis revealed that FgGST1 displays broad substrate specificity and shows high GSH conjugation activity toward 1-chloro-2,4-dinitrobenzene, 4-nitroquinoline-1-oxide, and trans-4-phenyl-3-butene-2-one and peroxidase activity towards trans-2-nonenal and hexa-2,4-dienal. The FgGST1 was highly sensitive to inhibition by cibacron blue. The cofactor (GSH) and inhibitor (cibacron blue) were docked, and binding sites were identified. The molecular dynamics studies and principal component analysis indicated the stability of the systems and the collective motions, respectively. Unfolding studies suggest that FgGST1 is a highly cooperative molecule because, during GdnHCl-induced denaturation, a simultaneous unfolding of the protein without stabilization of any partially folded intermediate is observed. The protein is stabilized with a conformational free energy of about 10 ± 0.3 kcal mol-1. Additionally, the presence of conserved Pro-53 and structural motifs such as N-capping box and hydrophobic staple, further aided in the stability and proper folding of FgGST1.
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Affiliation(s)
- Jupitara Kalita
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, India
| | - Rohit Shukla
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, India
| | - Harish Shukla
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, India
| | - Kundlik Gadhave
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, 175005, India
| | - Rajanish Giri
- School of Basic Sciences, Indian Institute of Technology Mandi, Kamand, Himachal Pradesh, 175005, India
| | - Timir Tripathi
- Molecular and Structural Biophysics Laboratory, Department of Biochemistry, North-Eastern Hill University, Shillong, 793022, India.
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21
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Thi THH, Priemel PA, Karrout Y, Driss V, Delbeke M, Dendooven A, Flament MP, Capron M, Siepmann J. Preparation and investigation of P28GST-loaded PLGA microparticles for immunomodulation of experimental colitis. Int J Pharm 2017; 533:26-33. [PMID: 28923765 DOI: 10.1016/j.ijpharm.2017.09.037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 09/12/2017] [Accepted: 09/14/2017] [Indexed: 01/07/2023]
Abstract
The aim of this work was to prepare and characterize (in vitro and in vivo) PLGA-based microparticles loaded with an enzymatic protein derived from the helminth parasite Schistosoma haematobium: glutathione S-transferase P28GST (P28GST). This protein is not only a promising candidate vaccine against schistosomiasis, it also exhibits interesting immunomodulating effects, which can be helpful for the regulation of inflammatory diseases. Helminths express a regulatory role on intestinal inflammation, and immunization by P28GST has recently been shown to be as efficient as infection to reduce inflammation in a murine colitis model. As an alternative to the combination with a classical adjuvant, long acting P28GST microparticles were prepared in order to induce colitis prevention. PLGA was used as biodegradable and biocompatible matrix former, and a W/O/W emulsion/solvent extraction technique applied to prepare different types of microparticles. The effects of key formulation and processing parameters (e.g., the polymer molecular weight, drug loading, W/O/W phase volumes and stirring rates of the primary/secondary emulsions) on the systems' performance were studied. Microparticles providing about constant P28GST release during several weeks were selected and their effects in an experimental model of colitis evaluated. Mice received P28GST-loaded or P28GST-free PLGA microparticles (s.c.) on Day 0, and optionally also on Days 14 and 28. Colitis was induced on Day 35, the animals were sacrificed on Day 37. Interestingly, the Wallace score (being a measure of the severity of the inflammation) was significantly lower in mice treated with P28GST microparticles compared to placebo after 1 or 3 injections. As immunogenicity markers, increased anti-P28GST IgG levels were detected after three P28GST PLGA microparticle injections, but not in the control groups. Thus, the proposed microparticles offer an interesting potential for the preventive treatment of experimental colitis, while the underlying mechanism of action is still to be investigated.
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Affiliation(s)
- T H Hoang Thi
- Univ. Lille, Inserm, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - P A Priemel
- Univ. Lille, Inserm, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - Y Karrout
- Univ. Lille, Inserm, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - V Driss
- Univ. Lille, Inserm, CHU Lille, U995 - Inflammation: Regulatory Mechanisms and Interactions With Nutrition and Candidosis, F-59000 Lille, France
| | - M Delbeke
- Univ. Lille, Inserm, CHU Lille, U995 - Inflammation: Regulatory Mechanisms and Interactions With Nutrition and Candidosis, F-59000 Lille, France
| | - A Dendooven
- Univ. Lille, Inserm, CHU Lille, U995 - Inflammation: Regulatory Mechanisms and Interactions With Nutrition and Candidosis, F-59000 Lille, France
| | - M P Flament
- Univ. Lille, Inserm, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France
| | - M Capron
- Univ. Lille, Inserm, CHU Lille, U995 - Inflammation: Regulatory Mechanisms and Interactions With Nutrition and Candidosis, F-59000 Lille, France
| | - J Siepmann
- Univ. Lille, Inserm, CHU Lille, U1008 - Controlled Drug Delivery Systems and Biomaterials, F-59000 Lille, France.
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22
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The schistosome glutathione S-transferase P28GST, a unique helminth protein, prevents intestinal inflammation in experimental colitis through a Th2-type response with mucosal eosinophils. Mucosal Immunol 2016; 9:322-35. [PMID: 26174763 PMCID: PMC4801903 DOI: 10.1038/mi.2015.62] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 05/30/2015] [Indexed: 02/04/2023]
Abstract
Intestinal helminth parasites are potent inducers of T helper type 2 (Th2) response and have a regulatory role, notably on intestinal inflammation. As infection with schistosomes is unlikely to provide a reliable treatment of inflammatory bowel diseases, we have investigated the beneficial effect of a schistosome enzymatic protein, the 28-kDa glutathione S-transferase (P28GST), on the modulation of disease activity and immune responses in experimental colitis. Our results showed that immunization with recombinant P28GST is at least as efficient as established schistosome infection to reduce colitis lesions and expression of pro-inflammatory cytokines. Considering underlying mechanisms, the decrease of inflammatory parameters was associated with the polarization of the immune system toward a Th2 profile, with local and systemic increases of interleukin (IL)-13 and IL-5. Dense eosinophil infiltration was observed in the colons of P28GST-immunized rats and mice. Depletion of eosinophils by treatment with an anti-Siglec-F monoclonal antibody and use of IL-5-deficient mice led to the loss of therapeutic effect, suggesting the crucial role for eosinophils in colitis prevention by P28GST. These findings reveal that immunization with P28GST, a unique recombinant schistosome enzyme, ameliorates intestinal inflammation through eosinophil-dependent modulation of harmful type 1 responses, representing a new immuno-regulatory strategy against inflammatory bowel diseases.
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Bae YA, Kim JG, Kong Y. Phylogenetic characterization of Clonorchis sinensis proteins homologous to the sigma-class glutathione transferase and their differential expression profiles. Mol Biochem Parasitol 2016; 206:46-55. [PMID: 26792248 DOI: 10.1016/j.molbiopara.2016.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 01/05/2016] [Accepted: 01/06/2016] [Indexed: 12/11/2022]
Abstract
Glutathione transferase (GST) is one of the major antioxidant proteins with diverse supplemental activities including peroxidase, isomerase, and thiol transferase. GSTs are classified into multiple classes on the basis of their primary structures and substrate/inhibitor specificity. However, the evolutionary routes and physiological environments specific to each of the closely related bioactive enzymes remain elusive. The sigma-like GSTs exhibit amino acid conservation patterns similar to the prostaglandin D synthases (PGDSs). In this study, we analyzed the phylogenetic position of the GSTs of the biocarcinogenic liver fluke, Clonorchis sinensis. We also observed induction profile of the GSTs in association with the parasite's maturation and in response to exogenous oxidative stresses, with special attention to sigma-class GSTs and PGDSs. The C. sinensis genome encoded 12 GST protein species, which were separately assigned to cytosolic (two omega-, one zeta-, two mu-, and five sigma-class), mitochondrial (one kappa-class), and microsomal (one membrane-associated proteins in eicosanoid and glutathione metabolism-like protein) GST families. Multiple sigma GST (or PGDS) orthologs were also detected in Opisthorchis viverrini. Other trematode species possessed only a single sigma-like GST gene. A phylogenetic analysis demonstrated that one of the sigma GST lineages duplicated in the common ancestor of trematodes were specifically expanded in the opisthorchiids, but deleted in other trematodes. The induction profiles of these sigma GST genes along with the development and aging of C. sinensis, and against various exogenous chemical stimuli strongly suggest that the paralogous sigma GST genes might be undergone specialized evolution to cope with the diverse hostile biochemical environments within the mammalian hepatobiliary ductal system.
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Affiliation(s)
- Young-An Bae
- Department of Microbiology, Gachon University Graduate School of Medicine, 191 Hambakmoe-ro, Yeonsu-gu, Incheon 21936, Republic of Korea
| | - Jeong-Geun Kim
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Yoon Kong
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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Pearson MS, Becker L, Driguez P, Young ND, Gaze S, Mendes T, Li XH, Doolan DL, Midzi N, Mduluza T, McManus DP, Wilson RA, Bethony JM, Nausch N, Mutapi F, Felgner PL, Loukas A. Of monkeys and men: immunomic profiling of sera from humans and non-human primates resistant to schistosomiasis reveals novel potential vaccine candidates. Front Immunol 2015; 6:213. [PMID: 25999951 PMCID: PMC4419842 DOI: 10.3389/fimmu.2015.00213] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 04/18/2015] [Indexed: 11/30/2022] Open
Abstract
Schistosoma haematobium affects more than 100 million people throughout Africa and is the causative agent of urogenital schistosomiasis. The parasite is strongly associated with urothelial cancer in infected individuals and as such is designated a group I carcinogen by the International Agency for Research on Cancer. Using a protein microarray containing schistosome proteins, we sought to identify antigens that were the targets of protective IgG1 immune responses in S. haematobium-exposed individuals that acquire drug-induced resistance (DIR) to schistosomiasis after praziquantel treatment. Numerous antigens with known vaccine potential were identified, including calpain (Smp80), tetraspanins, glutathione-S-transferases, and glucose transporters (SGTP1), as well as previously uncharacterized proteins. Reactive IgG1 responses were not elevated in exposed individuals who did not acquire DIR. To complement our human subjects study, we screened for antigen targets of rhesus macaques rendered resistant to S. japonicum by experimental infection followed by self-cure, and discovered a number of new and known vaccine targets, including major targets recognized by our human subjects. This study has further validated the immunomics-based approach to schistosomiasis vaccine antigen discovery and identified numerous novel potential vaccine antigens.
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Affiliation(s)
- Mark S Pearson
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University , Cairns, QLD , Australia
| | - Luke Becker
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University , Cairns, QLD , Australia
| | - Patrick Driguez
- QIMR Berghofer Medical Research Institute , Brisbane, QLD , Australia
| | - Neil D Young
- University of Melbourne , Melbourne, VIC , Australia
| | - Soraya Gaze
- Centro de Pesquisas Rene Rachou, Oswaldo Cruz Foundation , Belo Horizonte , Brazil
| | - Tiago Mendes
- Federal University of Minas Gerais , Belo Horizonte , Brazil
| | - Xiao-Hong Li
- National Institute of Parasitic Diseases , Shanghai , China
| | - Denise L Doolan
- QIMR Berghofer Medical Research Institute , Brisbane, QLD , Australia
| | - Nicholas Midzi
- National Institutes of Health Research , Harare , Zimbabwe
| | - Takafira Mduluza
- Department of Biochemistry, University of Zimbabwe , Harare , Zimbabwe
| | - Donald P McManus
- QIMR Berghofer Medical Research Institute , Brisbane, QLD , Australia
| | - R Alan Wilson
- Department of Biology, University of York , York , UK
| | - Jeffrey M Bethony
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University , Washington, DC , USA
| | | | | | | | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University , Cairns, QLD , Australia
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Angelucci F, Morea V, Angelaccio S, Saccoccia F, Contestabile R, Ilari A. The crystal structure of archaeal serine hydroxymethyltransferase reveals idiosyncratic features likely required to withstand high temperatures. Proteins 2014; 82:3437-49. [PMID: 25257552 DOI: 10.1002/prot.24697] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 01/19/2023]
Abstract
Serine hydroxymethyltransferases (SHMTs) play an essential role in one-carbon unit metabolism and are used in biomimetic reactions. We determined the crystal structure of free (apo) and pyridoxal-5'-phosphate-bound (holo) SHMT from Methanocaldococcus jannaschii, the first from a hyperthermophile, from the archaea domain of life and that uses H₄MPT as a cofactor, at 2.83 and 3.0 Å resolution, respectively. Idiosyncratic features were observed that are likely to contribute to structure stabilization. At the dimer interface, the C-terminal region folds in a unique fashion with respect to SHMTs from eubacteria and eukarya. At the active site, the conserved tyrosine does not make a cation-π interaction with an arginine like that observed in all other SHMT structures, but establishes an amide-aromatic interaction with Asn257, at a different sequence position. This asparagine residue is conserved and occurs almost exclusively in (hyper)thermophile SHMTs. This led us to formulate the hypothesis that removal of frustrated interactions (such as the Arg-Tyr cation-π interaction occurring in mesophile SHMTs) is an additional strategy of adaptation to high temperature. Both peculiar features may be tested by designing enzyme variants potentially endowed with improved stability for applications in biomimetic processes.
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Affiliation(s)
- Francesco Angelucci
- Department of Life, Health and Environmental Sciences, University of L'Aquila, P.le Salvatore Tommasi 1, L'Aquila, Italy
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Cytokine responses to the anti-schistosome vaccine candidate antigen glutathione-S-transferase vary with host age and are boosted by praziquantel treatment. PLoS Negl Trop Dis 2014; 8:e2846. [PMID: 24810615 PMCID: PMC4014416 DOI: 10.1371/journal.pntd.0002846] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Accepted: 03/25/2014] [Indexed: 01/17/2023] Open
Abstract
Background Improved helminth control is required to alleviate the global burden of schistosomiasis and schistosome-associated pathologies. Current control efforts rely on the anti-helminthic drug praziquantel (PZQ), which enhances immune responses to crude schistosome antigens but does not prevent re-infection. An anti-schistosome vaccine based on Schistosoma haematobium glutathione-S-transferase (GST) is currently in Phase III clinical trials, but little is known about the immune responses directed against this antigen in humans naturally exposed to schistosomes or how these responses change following PZQ treatment. Methodology Blood samples from inhabitants of a Schistosoma haematobium-endemic area were incubated for 48 hours with or without GST before (n = 195) and six weeks after PZQ treatment (n = 107). Concentrations of cytokines associated with innate inflammatory (TNFα, IL-6, IL-8), type 1 (Th1; IFNγ, IL-2, IL-12p70), type 2 (IL-4, IL-5, IL-13), type 17 (IL-17A, IL-21, IL-23p19) and regulatory (IL-10) responses were quantified in culture supernatants via enzyme-linked immunosorbent assay (ELISA). Factor analysis and multidimensional scaling were used to analyse multiple cytokines simultaneously. Principal Findings A combination of GST-specific type 2 (IL-5 and IL-13) and regulatory (IL-10) cytokines was significantly lower in 10–12 year olds, the age group at which S. haematobium infection intensity and prevalence peak, than in 4–9 or 13+ year olds. Following PZQ treatment there was an increase in the number of participants producing detectable levels of GST-specific cytokines (TNFα, IL-6, IL-8, IFNγ, IL-12p70, IL-13 and IL-23p19) and also a shift in the GST-specific cytokine response towards a more pro-inflammatory phenotype than that observed before treatment. Participant age and pre-treatment infection status significantly influenced post-treatment cytokine profiles. Conclusions/Significance In areas where schistosomiasis is endemic host age, schistosome infection status and PZQ treatment affect the cellular cytokine response to GST. Thus the efficacy of a GST-based vaccine may also be shaped by the demographic and epidemiological characteristics of targeted populations. Schistosomiasis is caused by infection with Schistosoma spp. parasites, for which the main treatment is the drug praziquantel (PZQ). Since PZQ does not prevent reinfection, an anti-schistosome vaccine based on the Schistosoma haematobium enzyme glutathione-S-transferase (GST) is being developed. In this study we investigated the GST-specific immune responses of people naturally exposed to schistosomes and the affect that PZQ has on these responses. We cultured blood samples from a schistosome-exposed community with GST before and six weeks after PZQ treatment and measured a range of soluble proteins (cytokines) in culture supernatants as indicators of blood cell activation and phenotype. Before treatment, GST-specific cytokine responses varied with host age, particularly in children with high intensity schistosome infections. Following treatment, GST activated blood samples from more individuals to produce a broader range of cytokines and the combination of GST-specific cytokine responses reflected a more pro-inflammatory immune phenotype than that observed pre-treatment. Post-treatment responses varied according to host age and pre-treatment infection status. Taken together, our study suggests that current and future GST-based vaccine trials should take host age, schistosome infection status and PZQ treatment history into account since these factors influence GST-specific immune activation.
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Crystal structures of 26kDa Clonorchis sinensis glutathione S-transferase reveal zinc binding and putative metal binding. Biochem Biophys Res Commun 2013; 438:457-61. [PMID: 23916611 DOI: 10.1016/j.bbrc.2013.07.102] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 07/25/2013] [Indexed: 11/23/2022]
Abstract
The crystal structures of CsGST in two different space groups revealed that Asp26 and His79 coordinate a zinc ion. In one space group, His46 of an adjacent molecule participates in the coordination within 2.0Å. In the other space group, Asp26, His79 and a water molecule coordinate a zinc ion. The CsGST-D26H structure showed that four histidine residues - His26 and His79 from one molecule and the same residues from a symmetry-related neighboring molecule - coordinate a zinc ion. The coordinated zinc ions are located between two molecules and mediate molecular contacts within the crystal.
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Bocedi A, Fabrini R, Farrotti A, Stella L, Ketterman AJ, Pedersen JZ, Allocati N, Lau PCK, Grosse S, Eltis LD, Ruzzini A, Edwards TE, Morici L, Del Grosso E, Guidoni L, Bovi D, Lo Bello M, Federici G, Parker MW, Board PG, Ricci G. The impact of nitric oxide toxicity on the evolution of the glutathione transferase superfamily: a proposal for an evolutionary driving force. J Biol Chem 2013; 288:24936-47. [PMID: 23828197 DOI: 10.1074/jbc.m113.476135] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Glutathione transferases (GSTs) are protection enzymes capable of conjugating glutathione (GSH) to toxic compounds. During evolution an important catalytic cysteine residue involved in GSH activation was replaced by serine or, more recently, by tyrosine. The utility of these replacements represents an enigma because they yield no improvements in the affinity toward GSH or in its reactivity. Here we show that these changes better protect the cell from nitric oxide (NO) insults. In fact the dinitrosyl·diglutathionyl·iron complex (DNDGIC), which is formed spontaneously when NO enters the cell, is highly toxic when free in solution but completely harmless when bound to GSTs. By examining 42 different GSTs we discovered that only the more recently evolved Tyr-based GSTs display enough affinity for DNDGIC (KD < 10(-9) M) to sequester the complex efficiently. Ser-based GSTs and Cys-based GSTs show affinities 10(2)-10(4) times lower, not sufficient for this purpose. The NO sensitivity of bacteria that express only Cys-based GSTs could be related to the low or null affinity of their GSTs for DNDGIC. GSTs with the highest affinity (Tyr-based GSTs) are also over-represented in the perinuclear region of mammalian cells, possibly for nucleus protection. On the basis of these results we propose that GST evolution in higher organisms could be linked to the defense against NO.
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Affiliation(s)
- Alessio Bocedi
- Department of Chemical Sciences and Technologies, University of Rome, Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
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Vila-Viçosa D, Teixeira VH, Santos HAF, Machuqueiro M. Conformational Study of GSH and GSSG Using Constant-pH Molecular Dynamics Simulations. J Phys Chem B 2013; 117:7507-17. [DOI: 10.1021/jp401066v] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Diogo Vila-Viçosa
- Centro de Química
e Bioquímica and Departamento
de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Vitor H. Teixeira
- Centro de Química
e Bioquímica and Departamento
de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Hugo A. F. Santos
- Centro de Química
e Bioquímica and Departamento
de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Miguel Machuqueiro
- Centro de Química
e Bioquímica and Departamento
de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
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Iriarte A, Arbildi P, La-Rocca S, Musto H, Fernández V. Identification of novel glutathione transferases in Echinococcus granulosus. An evolutionary perspective. Acta Trop 2012; 123:208-16. [PMID: 22659461 DOI: 10.1016/j.actatropica.2012.05.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Revised: 03/28/2012] [Accepted: 05/18/2012] [Indexed: 11/24/2022]
Abstract
Glutathione transferase enzymes (GSTs) constitute a major detoxification system in helminth parasites and have been related to the modulation of host immune response mechanisms. At least three different GSTs classes have been described in Platyhelminthes: Mu, Sigma and Omega. Mining the genome of Echinococcus multilocularis and the ESTs databases of Taenia solium and E. granulosus identified two new GSTs from the cestode E. granulosus, named EgGST2 and EgGST3. It also revealed that the Omega class of GSTs was absent from the Taenidae family. EgGST2 and EgGST3 are actively expressed in the parasite. In order to know the origin of these new GSTs, in silico analyses were performed. While EgGST2 is classified as belonging to the Sigma class, the data obtained for EgGST3 allowed a less clear interpretation. The study of the evolutionary relatedness based on the C-terminal domain sequence, gene structure conservation and three-dimensional structure predictions, suggests that EgGST3 is derived from the Platyhelminthes' Sigma-class cluster. Interestingly, the N-terminal domain displays some characteristic Omega-class residues, including a Cys residue that is likely to be involved in the catalytic mechanism. We discuss different evolutionary scenarios that could explain the observed patterns.
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Abstract
Oesophagostomum dentatum stages were investigated for glutathione S-transferase (GST) expression at the protein and mRNA levels. GST activity was detected in all stages (infectious and parasitic stages including third- and fourth-stage larvae of different ages as well as males and females) and could be dose-dependently inhibited with sulfobromophthalein (SBP). Addition of SBP to in vitro larval cultures reversibly inhibited development from third- to fourth-stage larvae. Two glutathione-affinity purified proteins (23 and 25 kDa) were detected in lysates of exsheathed third-stage larvae by SDS-PAGE. PCR-primers were designed based on peptide sequences and conserved GST sequences of other nematodes for complete cDNA sequences (621 and 624 nt) of 2 isoforms, Od-GST1 and Od-GST2, with 72% nucleotide similarity and 75% for the deduced proteins. Genomic sequences consisted of 7 exons and 6 introns spanning 1296 bp for Od-GST1 and 1579 and 1606 bp for Od-GST2. Quantitative real-time-PCR revealed considerably elevated levels of Od-GST1 in the early parasitic stages and slightly reduced levels of Od-GST2 in male worms. Both Od-GSTs were most similar to GST of Ancylostoma caninum (nucleotides: 73 and 70%; amino acids: 80 and 73%). The first three exons (75 amino acids) corresponded to a synthetic prostaglandin D2 synthase (53% similarity). O. dentatum GSTs might be involved in intrinsic metabolic pathways which could play a role both in nematode physiology and in host-parasite interactions.
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Deville J, Rey J, Chabbert M. Comprehensive analysis of the helix-X-helix motif in soluble proteins. Proteins 2008; 72:115-35. [PMID: 18214950 DOI: 10.1002/prot.21879] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Alpha-helices are the most common secondary structures found in globular proteins. In this report, we analyze the stereochemical and sequence properties of helix-X-helix (HXH) motifs in which two alpha-helices are linked by a single residue, in search of characteristic structures and sequence signals. The analysis is carried out on a database of 837 nonredundant HXH motifs. The kinks are characterized by the bend angle between the axes of the N-terminal and C-terminal helices and the wobble angle corresponding to the rotation of C-terminal helix axis on the plane perpendicular to the N-terminal one. The phi-psi dihedral angles of the linker residue are clustered in six distinct areas of the Ramachandran plot: two areas are located in the additional allowed alpha region (alpha(1) and alpha(2)), two areas are in the additional allowed beta region (beta(1) and beta(2)) and two areas have positive phi values (alpha(L) and beta(M)). Each phi/psi region corresponds to characteristic bend and wobble angles and amino acid distributions. Bend angles can vary from 0 degrees to 160 degrees. Most wobble angles correspond to a counter-clockwise rotation of the C-terminal helix. Proline residues are rigorously excluded from the linker position X but have a high propensity at position X+1 of the beta(1) and beta(2) motifs (12 and 7, respectively) and at position X+3 of the alpha(1) motifs (9). Glycine linkers are located either in the alpha(L) region (20%) or in the beta(M) region (80%). This latter conformation is characterized by a marked bend angle (124 degrees +/- 18 degrees) and a clockwise wobble. Among other amino acids, Asn is remarkable for its high propensity (>3) at the linker position of the alpha(2), beta(1), and beta(2) motifs. Stabilization of HXH motifs by H-bonds between polar side chains of the linker and polar groups of the backbone is determined. A method based on position-specific scoring matrices is developed for conformational prediction. The accuracy of the predictions reaches 80% when the method is applied to proline-induced kinks or to kinks with bend angles in the 50 degrees-100 degrees range.
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Affiliation(s)
- Julie Deville
- CNRS UMR 6214-INSERM U771, Université d'Angers, Faculté de Médecine, 3 rue Haute de Reculée, 49045 Angers, France
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Hervé C, de Franco PO, Groisillier A, Tonon T, Boyen C. New members of the glutathione transferase family discovered in red and brown algae. Biochem J 2008; 412:535-44. [PMID: 18315526 DOI: 10.1042/bj20071464] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The GSTs (glutathione transferases) are involved in the detoxification of a wide variety of hydrophobic substrates. These enzymes have been found in virtually all types of organisms, including plants, animals, nematodes and bacteria. In the present study, we report the molecular and biochemical characterization of algal GSTs. Phylogenetic analysis showed that most of them were distinct from previously described GST classes, but were most closely related to the Sigma class. Profiling of GST genes from the red alga Chondrus crispus and brown alga Laminaria digitata was undertaken after different chemical treatments and showed that they displayed contrasting patterns of transcription. Recombinant algal GST from both species showed transferase activities against the common substrates aryl halides, but also on the alpha,beta-unsaturated carbonyl 4-hydroxynonenal. Also, they exhibit significant peroxidation towards organic hydroperoxides, including oxygenated derivatives of polyunsaturated fatty acids. Among a range of compounds tested, Cibacron Blue was the most efficient inhibitor of algal GSTs identified.
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Affiliation(s)
- Cécile Hervé
- UPMC Univ. Paris 6, UMR 7139 Végétaux Marins et Biomolécules, Station Biologique, F 29682, Roscoff, France
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Structure of the Extracellular Glutathione S-Transferase OvGST1 from the Human Pathogenic Parasite Onchocerca volvulus. J Mol Biol 2008; 377:501-11. [DOI: 10.1016/j.jmb.2008.01.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2007] [Revised: 01/09/2008] [Accepted: 01/09/2008] [Indexed: 11/23/2022]
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Sakamoto T, Oikawa T. Cubic crystal protein inclusions in the neodermis of the pancreatic fluke, Eurytrema pancreaticum, and Eurytrema coelomaticum. Parasitol Res 2007; 101:1393-9. [PMID: 17657508 DOI: 10.1007/s00436-007-0658-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 06/23/2007] [Accepted: 06/27/2007] [Indexed: 10/23/2022]
Abstract
Light microscopy of Eurytrema pancreaticum and Eurytrema coelomaticum collected from cattle in Japan, China, Thailand, and Brazil showed many cubic crystal inclusions in the neodermis (tegument) of all flukes. The crystal inclusions were histochemically positive for protein. Scanning electron microscopy showed many cubic protrusions containing cubic crystal protein inclusions on the surface of the neodermis. Transmission electron microscopy showed that cubic crystal protein inclusions appeared in the perikarya of subtegumental parts, passed through the cytoplasmic bridge, moved into the syncytial neodermal cytoplasm, and then protruded from, and finally separated from, the neodermal cytoplasm. Cubic crystal protein inclusions were hexahedral with each side 2-18 microm long. High-resolution microscopy of ultrathin sections of crystal inclusions showed a lattice fringe at spacings of about 0.52 nm by using a filtering processing. Diffractograms were obtained by Fourier transform of the images. The lattice structure of the crystal protein inclusions was shown by inverse Fourier transform, indicating that the cubic crystal protein inclusions were single crystals. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis estimated the molecular weight of protein in the cubic crystal inclusion as 36.6 kDa. Energy-dispersive X-ray spectroscopy proved that the cubic crystal protein inclusions were composed of protein and sulfur.
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Affiliation(s)
- Tsukasa Sakamoto
- School of Veterinary Medicine, Faculty of Agriculture, Iwate University, Ueda 3-chome 18-8, Morioka, Iwate, 020-8550, Japan.
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Kubata BK, Duszenko M, Martin KS, Urade Y. Molecular basis for prostaglandin production in hosts and parasites. Trends Parasitol 2007; 23:325-31. [PMID: 17531535 DOI: 10.1016/j.pt.2007.05.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2006] [Revised: 03/20/2007] [Accepted: 05/11/2007] [Indexed: 11/22/2022]
Abstract
Prostaglandins (PGs) comprise a family of structurally related bioactive lipid mediators that are involved in various symptoms associated with parasitic diseases. The molecular mechanisms of PG biosynthesis in animals have been studied extensively. Currently, several lines of evidence link their production with parasites. In this review we discuss the roles of PGs in parasite pathogenesis and physiology and the recent advances in our understanding of the enzymology of PG production in various parasites.
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Affiliation(s)
- Bruno Kilunga Kubata
- Biosciences Eastern and Central Africa (a NEPAD centre of excellence), PO Box 30709, 00100 Nairobi, Kenya.
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Baiocco P, Gourlay LJ, Angelucci F, Fontaine J, Hervé M, Miele AE, Trottein F, Brunori M, Bellelli A. Probing the Mechanism of GSH Activation in Schistosoma haematobium Glutathione-S-transferase by Site-directed Mutagenesis and X-ray Crystallography. J Mol Biol 2006; 360:678-89. [PMID: 16777141 DOI: 10.1016/j.jmb.2006.05.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Revised: 05/10/2006] [Accepted: 05/16/2006] [Indexed: 11/17/2022]
Abstract
During turnover, the catalytic tyrosine residue (Tyr10) of the sigma class Schistosoma haematobium wild-type glutathione-S-transferase is expected to switch alternately in and out of the reduced glutathione-binding site (G-site). The Tyrout10 conformer forms a pi-cation interaction with the guanidinium group of Arg21. As in other similar glutathione-S-transferases, the catalytic Tyr has a low pKa of 7.2. In order to investigate the catalytic role of Tyr10, and the structural and functional roles of Arg21, we carried out structural studies on two Arg21 mutants (R21L and R21Q) and a Tyr10 mutant, Y10F. Our crystallographic data for the two Arg21 mutants indicate that only the Tyrout10 conformation is populated, thereby excluding a role of Arg21 in the stabilisation of the out conformation. However, Arg21 was confirmed to be catalytically important and essential for the low pKa of Tyr10. Upon comparison with structural data generated for reduced glutathione-bound and inhibitor-bound wild-type enzymes, it was observed that the orientations of Tyr10 and Arg35 are concerted and that, upon ligand binding, minor rearrangements occur within conserved residues in the active site loop. These rearrangements are coupled to quaternary rigid-body movements at the dimer interface and alterations in the localisation and structural order of the C-terminal domain.
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Affiliation(s)
- Paola Baiocco
- Department of Biochemical Sciences A. Rossi Fanelli and Istituto Pasteur- Fondazione Cenci Bolognetti, University of Rome La Sapienza, Rome, Italy
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Angelucci F, Baiocco P, Brunori M, Gourlay L, Morea V, Bellelli A. Insights into the Catalytic Mechanism of Glutathione S-Transferase: The Lesson from Schistosoma haematobium. Structure 2005; 13:1241-6. [PMID: 16154081 DOI: 10.1016/j.str.2005.06.007] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2005] [Revised: 06/19/2005] [Accepted: 06/20/2005] [Indexed: 11/21/2022]
Abstract
Glutathione S-transferases (GSTs) are involved in detoxification of xenobiotic compounds and in the biosynthesis of important metabolites. All GSTs activate glutathione (GSH) to GS(-); in many GSTs, this is accomplished by a Tyr at H-bonding distance from the sulfur of GSH. The high-resolution structure of GST from Schistosoma haematobium revealed that the catalytic Tyr occupies two alternative positions, one external, involving a pi-cation interaction with the conserved Arg21, and the other inside the GSH binding site. The interaction with Arg21 lowers the pK(a) of the catalytic Tyr10, as required for catalysis. Examination of several other GST structures revealed the presence of an external pocket that may accommodate the catalytic Tyr, and suggested that the change in conformation and acidic properties of the catalytic Tyr may be shared by other GSTs. Arginine and two other residues of the external pocket constitute a conserved structural motif, clearly identified by sequence comparison.
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Affiliation(s)
- Francesco Angelucci
- Istituto di Biologia e Patologia Molecolari del CNR, Department of Biochemical Sciences A. Rossi Fanelli, University of Rome La Sapienza, 00185 Rome, Italy
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Capron A, Riveau G, Capron M, Trottein F. Schistosomes: the road from host-parasite interactions to vaccines in clinical trials. Trends Parasitol 2005; 21:143-9. [PMID: 15734662 DOI: 10.1016/j.pt.2005.01.003] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Insights over recent years into the interactions between helminths, including schistosomes, and the immune system have generated new concepts in immunology and significant advances in vaccine strategies. Here, we report recent advances that substantially increase our understanding of the nature of the host innate and adaptive responses to schistosomes and on strategies elaborated by the parasite to manipulate such responses. We also describe the long road that has allowed us to move from the identification of an anti-schistosome vaccine candidate, a 28kDa glutathione-S-transferase, to its recent evaluation in human clinical trials.
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Affiliation(s)
- André Capron
- Unité Inserm U547, Institut Pasteur, 1 rue du Professeur Calmette, BP 245, 59019 Lille cedex, France.
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Perbandt M, Höppner J, Betzel C, Walter RD, Liebau E. Structure of the major cytosolic glutathione S-transferase from the parasitic nematode Onchocerca volvulus. J Biol Chem 2005; 280:12630-6. [PMID: 15640152 DOI: 10.1074/jbc.m413551200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Onchocerciasis is a debilitating parasitic disease caused by the filarial worm Onchocerca volvulus. Similar to other helminth parasites, O. volvulus is capable of evading the host's immune responses by a variety of defense mechanisms, including the detoxification activities of the glutathione S-transferases (GSTs). Additionally, in response to drug treatment, helminth GSTs are highly up-regulated, making them tempting targets both for chemotherapy and for vaccine development. We analyzed the three-dimensional x-ray structure of the major cytosolic GST from O. volvulus (Ov-GST2) in complex with its natural substrate glutathione and its competitive inhibitor S-hexylglutathione at 1.5 and 1.8 angstrom resolution, respectively. From the perspective of the biochemical classification, the Ov-GST2 seems to be related to pi-class GSTs. However, in comparison to other pi-class GSTs, in particular to the host's counterpart, the Ov-GST2 reveals significant and unusual differences in the sequence and overall structure. Major differences can be found in helix alpha-2, an important region for substrate recognition. Moreover, the binding site for the electrophilic co-substrate is spatially increased and more solvent-accessible. These structural alterations are responsible for different substrate specificities and will form the basis of parasite-specific structure-based drug design investigations.
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Affiliation(s)
- Markus Perbandt
- Institute of Biochemistry and Foodchemistry, Department of Biochemistry and Molecularbiology, University of Hamburg, Martin Luther King Platz 6, 20146 Hamburg, Germany.
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Rowley AF, Vogan CL, Taylor GW, Clare AS. Prostaglandins in non-insectan invertebrates: recent insights and unsolved problems. J Exp Biol 2005; 208:3-14. [PMID: 15601872 DOI: 10.1242/jeb.01275] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SUMMARYProstaglandins (PG) are oxygenated derivatives of C20 polyunsaturated fatty acids including arachidonic and eicosapentaenoic acids. In mammals, these compounds have been shown to play key roles in haemostasis, sleep-wake regulation, smooth muscle tone, and vaso-, temperature and immune regulation. In invertebrates, PGs have been reported to perform similar roles and are involved in the control of oogenesis and spermatogenesis, ion transport and defence. Although there is often a detailed understanding of the actions of these compounds in invertebrates such as insects, knowledge of their mechanism of biosynthesis is often lacking. This account provides a critical review of our current knowledge on the structure and modes of biosynthesis of PGs in invertebrates, with particular reference to aquatic invertebrates. It emphasises some of the most recent findings, which suggest that some PGs have been misidentified.Prostaglandins in invertebrates can be categorised into two main types; the classical forms, such as PGE2 and PGD2 that are found in mammals, and novel forms including clavulones, bromo- and iodo-vulones and various PGA2 and PGE2 esters. A significant number of reports of PG identification in invertebrates have relied upon methods such as enzyme immunoassay that do not have the necessary specificity to ensure the validity of the identification. For example, in the barnacle Balanus amphitrite, although there are PG-like compounds that bind to antibodies raised against PGE2, mass spectrometric analysis failed to confirm the presence of this and other classical PGs. Therefore, care should be taken in drawing conclusions about what PGs are formed in invertebrates without employing appropriate analytical methods. Finally, the recent publication of the Ciona genome should facilitate studies on the nature and mode of biosynthesis of PGs in this advanced deuterostomate invertebrate.
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Affiliation(s)
- Andrew F Rowley
- School of Biological Sciences, University of Wales Swansea, Singleton Park, Swansea SA2 8PP, UK.
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Deponte M, Becker K. Glutathione S‐transferase from Malarial Parasites: Structural and Functional Aspects. Methods Enzymol 2005; 401:241-53. [PMID: 16399390 DOI: 10.1016/s0076-6879(05)01015-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Malaria represents an emerging disease because of increasing parasite resistance against available drugs and because of increasing geographical distribution of the causative agent, Plasmodium falciparum. The complete genome of Plasmodium was sequenced recently, revealing that the parasite harbors only one glutathione S-transferase (PfGST). This observation was of particular interest: First, certain antimalarial drugs such as chloroquine and methylene blue presumably influence the glutathione metabolism in which PfGST is involved. Second, PfGST might play a significant role in drug resistance. PfGST was studied in parasite extracts and as recombinant protein, and its x-ray structure has been solved. The available data indicate that the homodimeric PfGST cannot be assigned to any of the previously known GST classes. PfGST exhibits significant structural differences to human GSTs, particularly at the so-called hydrophobic binding pocket (H-site) where the second substrate binds. Inhibition of PfGST is expected to act at different vulnerable metabolic sites of the parasite in parallel; it is likely to disturb GSH-dependent detoxification processes, to increase the levels of cytotoxic peroxides, and possibly to increase the concentration of toxic hemin. In this chapter, we summarize the current knowledge on PfGST, including aspects of structure, function, and future drug development.
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Affiliation(s)
- Marcel Deponte
- Interdisciplinary Research Center, Giessen University, Germany
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