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Maharjan S, Kirk RS, Lawton SP, Walker AJ. Human growth factor-mediated signalling through lipid rafts regulates stem cell proliferation, development and survival of Schistosoma mansoni. Open Biol 2024; 14:230262. [PMID: 38195062 PMCID: PMC10776228 DOI: 10.1098/rsob.230262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Accepted: 11/16/2023] [Indexed: 01/11/2024] Open
Abstract
Although the mechanisms by which schistosomes grow and develop in humans are poorly defined, their unique outer tegument layer, which interfaces with host blood, is considered vital to homeostasis of the parasite. Here, we investigated the importance of tegument lipid rafts to the biology of Schistosoma mansoni in the context of host-parasite interactions. We demonstrate the temporal clustering of lipid rafts in response to human epidermal growth factor (EGF) during early somule development, concomitant with the localization of anteriorly orientated EGF receptors (EGFRs) and insulin receptors, mapped using fluorescent EGF/insulin ligand. Methyl-β-cyclodextrin (MβCD)-mediated depletion of cholesterol from lipid rafts abrogated the EGFR/IR binding at the parasite surface and led to modulation of protein kinase C, extracellular signal-regulated kinase, p38 mitogen-activated protein kinase and Akt signalling pathways within the parasite. Furthermore, MβCD-mediated lipid raft disruption, and blockade of EGFRs using canertinib, profoundly reduced somule motility and survival, and attenuated stem cell proliferation and somule growth and development particularly to the fast-growing liver stage. These findings provide a novel paradigm for schistosome development and vitality in the host, driven through host-parasite interactions at the tegument, that might be exploitable for developing innovative therapeutic approaches to combat human schistosomiasis.
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Affiliation(s)
- Shradha Maharjan
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK
| | - Ruth S. Kirk
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK
| | - Scott P. Lawton
- Centre for Epidemiology and Planetary Health, SRUC School of Veterinary Medicine, Scotland's Rural College, West Mains Road, Edinburgh EH9 3JG, UK
| | - Anthony J. Walker
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, Penrhyn Road, Kingston upon Thames KT1 2EE, UK
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2
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Human serum activates the tegument of female schistosomes and supports recovery from Praziquantel. Parasitol Res 2020; 120:209-221. [PMID: 33263166 PMCID: PMC7846515 DOI: 10.1007/s00436-020-06968-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 11/04/2020] [Indexed: 02/08/2023]
Abstract
Schistosomiasis is one of the most devastating parasitic disease in the world. Schistosoma spp. survive for decades within the vasculature of their human hosts. They have evolved a vast array of mechanisms to avoid the immune reaction of the host. Due to their sexual dimorphism, with the female worm lying within the gynecophoric canal of the male worm, it is the male that is exposed to the immediate environment and the soluble parts of the host’s immune response. To understand how the worms are so successful in fending off the immune attacks of the host, comparative analyses of both worm sexes in human serum (with or without Praziquantel) were performed using scanning electron microscopy, transmission electron microscopy, and immunohistochemistry. Further, gene expression analyses of tegument-specific genes were performed. Following the incubation in human serum, males and females out of pairs show morphological changes such as an altered structure of the pits below the surface and an increased number of pits per area. In addition, female schistosomes presented a marked tuft-like repulsion of their opsonized surface. The observed resistance of females to Praziquantel seemed to depend on active proteins in the human serum. Moreover, different expression profiles of tegument-specific genes indicate different functions of female_single and male_single teguments in response to human serum. Our results indicate that female schistosomes developed different evasion strategies toward the host’s immune system in comparison to males that might lead to more robustness and has to be taken into account for the development of new anti-schistosomal drugs.
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Angeles JMM, Mercado VJP, Rivera PT. Behind Enemy Lines: Immunomodulatory Armamentarium of the Schistosome Parasite. Front Immunol 2020; 11:1018. [PMID: 32582161 PMCID: PMC7295904 DOI: 10.3389/fimmu.2020.01018] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Accepted: 04/28/2020] [Indexed: 12/11/2022] Open
Abstract
The deeply rooted, intricate relationship between the Schistosoma parasite and the human host has enabled the parasite to successfully survive within the host and surreptitiously evade the host's immune attacks. The parasite has developed a variety of strategies in its immunomodulatory armamentarium to promote infection without getting harmed or killed in the battlefield of immune responses. These include the production of immunomodulatory molecules, alteration of membranes, and the promotion of granuloma formation. Schistosomiasis thus serves as a paradigm for understanding the Th2 immune responses seen in various helminthiases. This review therefore aims to summarize the immunomodulatory mechanisms of the schistosome parasites to survive inside the host. Understanding these immunomodulatory strategies not only provides information on parasite-host interactions, but also forms the basis in the development of novel drugs and vaccines against the schistosome infection, as well as various types of autoimmune and inflammatory conditions.
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Affiliation(s)
- Jose Ma M Angeles
- Department of Parasitology, College of Public Health, University of the Philippines Manila, Manila, Philippines
| | - Van Jerwin P Mercado
- Department of Parasitology, College of Public Health, University of the Philippines Manila, Manila, Philippines
| | - Pilarita T Rivera
- Department of Parasitology, College of Public Health, University of the Philippines Manila, Manila, Philippines
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Ressurreição M, Elbeyioglu F, Kirk RS, Rollinson D, Emery AM, Page NM, Walker AJ. Molecular characterization of host-parasite cell signalling in Schistosoma mansoni during early development. Sci Rep 2016; 6:35614. [PMID: 27762399 PMCID: PMC5071895 DOI: 10.1038/srep35614] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 10/04/2016] [Indexed: 02/04/2023] Open
Abstract
During infection of their human definitive host, schistosomes transform rapidly from free-swimming infective cercariae in freshwater to endoparasitic schistosomules. The 'somules' next migrate within the skin to access the vasculature and are surrounded by host molecules that might activate intracellular pathways that influence somule survival, development and/or behaviour. However, such 'transactivation' by host factors in schistosomes is not well defined. In the present study, we have characterized and functionally localized the dynamics of protein kinase C (PKC) and extracellular signal-regulated kinase (ERK) activation during early somule development in vitro and demonstrate activation of these protein kinases by human epidermal growth factor, insulin, and insulin-like growth factor I, particularly at the parasite surface. Further, we provide evidence that support the existence of specialized signalling domains called lipid rafts in schistosomes and propose that correct signalling to ERK requires proper raft organization. Finally, we show that modulation of PKC and ERK activities in somules affects motility and reduces somule survival. Thus, PKC and ERK are important mediators of host-ligand regulated transactivation events in schistosomes, and represent potential targets for anti-schistosome therapy aimed at reducing parasite survival in the human host.
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Affiliation(s)
- Margarida Ressurreição
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, KT1 2EE, United Kingdom
| | - Firat Elbeyioglu
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, KT1 2EE, United Kingdom
| | - Ruth S. Kirk
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, KT1 2EE, United Kingdom
| | - David Rollinson
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom
| | - Aidan M. Emery
- Department of Life Sciences, The Natural History Museum, London, SW7 5BD, United Kingdom
| | - Nigel M. Page
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, KT1 2EE, United Kingdom
| | - Anthony J. Walker
- Molecular Parasitology Laboratory, School of Life Sciences, Pharmacy and Chemistry, Kingston University, KT1 2EE, United Kingdom
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5
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El-Shabasy EA, Reda ES, Abdeen SH, Said AE, Ouhtit A. Transmission electron microscopic observations on ultrastructural alterations in Schistosoma mansoni adult worms recovered from C57BL/6 mice treated with radiation-attenuated vaccine and/or praziquantel in addition to passive immunization with normal and vaccinated rabbit sera against infection. Parasitol Res 2015; 114:1563-80. [PMID: 25786393 DOI: 10.1007/s00436-015-4341-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 01/22/2015] [Indexed: 01/07/2023]
Abstract
Although the current treatment of schistosomiasis relies largely on praziquantel (PZQ), it has not been successful in significantly reducing the overall rate of disease cases, one of the suggested reasons being the inevitable resistance to PZQ. Previous studies showed that radiation-attenuated vaccine provides protection against Schistosoma mansoni in a host of various species. In the present study, we evaluated the effect of various vaccination strategies in C57BL/6 mice, including single or multiple vaccination strategy, subcurative dose (20 mg/kg) of PZQ, and a combination of single vaccination with subcurative dose of PZQ. Treatment either with subcurative dose of PZQ or with a single vaccination of attenuated cercariae (500 per mouse), caused significant reduction in total worm burden, hepatic, and intestinal ova counts of 43.03, 73.2, and 59.5 and 37.97, 52.02, and 26.3%, respectively. Furthermore, tegumental changes were observed. In multiple vaccinated group, there was an extensive lysis in tegumental layers. High deformations in gastrodermis, testis cells, vitelline cells, and oocytes were recorded. Also, this study is to explore the role of humoral immunity using highly resistant rabbits that had been exposed to three immunizations with ultraviolet (UV)-irradiated cercariae (8000 per rabbit in each immunization), and their sera were tested for their ability to transfer protection. The reduction in challenge worm burden had reached 32.76-43.64% when compared with recipients of normal serum or no serum. The reduction in hepatic and intestinal ova counts reached to 74.4 and 71.08% in group immunized with vaccinated rabbit sera. Swelling and extensive lysis of tegumental layers, gastrodermis lumen, spermatocytes, and deformation of oocytes were recorded with more severity than that recorded in normal rabbit sera group. Our findings recorded that multiple vaccination strategy is the most effective strategy then passive transfer of vaccinated rabbit. This gives guiding in the design the appropriate therapeutic strategy.
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Affiliation(s)
- Eman A El-Shabasy
- Department of Zoology, Faculty of Science, Mansoura University, Mansoura, Egypt,
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Evaluation of the use of C-terminal part of the Schistosoma mansoni 200kDa tegumental protein in schistosomiasis diagnosis and vaccine formulation. Exp Parasitol 2014; 139:24-32. [DOI: 10.1016/j.exppara.2014.02.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 01/31/2014] [Accepted: 02/09/2014] [Indexed: 11/22/2022]
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Sulbarán G, Noya O, Brito B, Ballén DE, Cesari IM. Immunoprotection of mice against Schistosomiasis mansoni using solubilized membrane antigens. PLoS Negl Trop Dis 2013; 7:e2254. [PMID: 23818994 PMCID: PMC3688544 DOI: 10.1371/journal.pntd.0002254] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 04/26/2013] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Schistosomiasis continues to be one of the most prevalent parasitic diseases in the world. Despite the existence of a highly effective antischistosome drug, the disease is spreading into new areas, and national control programs do not arrive to complete their tasks particularly in low endemic areas. The availability of a vaccine could represent an additional component to chemotherapy. Experimental vaccination studies are however necessary to identify parasite molecules that would serve as vaccine candidates. In the present work, C57BL/6 female mice were subcutaneously immunized with an n-butanol extract of the adult worm particulate membranous fraction (AWBE) and its protective effect against a S. mansoni challenge infection was evaluated. METHODOLOGY AND FINDINGS Water-saturated n-butanol release into the aqueous phase a set of membrane-associated (glyco)proteins that are variably recognized by antibodies in schistosome-infected patients; among the previously identified AWBE antigens there is Alkaline Phosphatase (SmAP) which has been associated with resistance to the infection in mice. As compared to control, a significantly lower number of perfuse parasites was obtained in the immunized/challenged mouse group (P<0.05, t test); and consequently, a lower number of eggs and granulomas (with reduced sizes), overall decreasing pathology. Immunized mice produced high levels of sera anti-AWBE IgG recognizing antigens of ∼190-, 130-, 98-, 47-, 28-23, 14-, and 9-kDa. The ∼130-kDa band (the AP dimer) exhibited in situ SmAP activity after addition of AP substrate and the activity was not apparently inhibited by host antibodies. A preliminary proteomic analysis of the 25-, 27-, and 28-kDa bands in the immunodominant 28-23 kDa region suggested that they are composed of actin. CONCLUSIONS Immunization with AWBE induced the production of specific antibodies to various adult worm membrane molecules (including AP) and a partial (43%) protection against a challenging S. mansoni infection by mechanism(s) that still has to be elucidated.
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Affiliation(s)
- Guidenn Sulbarán
- Unidad de Trematodiasis, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
| | - Oscar Noya
- Sección de Biohelmintiasis, Instituto de Medicina Tropical, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela
| | - Beatríz Brito
- Laboratorio de Patología Celular y Molecular, Centro de Medicina Experimental, Instituto de Investigaciones Científicas, Caracas, Venezuela
| | - Diana E. Ballén
- Unidad de Trematodiasis, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
| | - Italo M. Cesari
- Unidad de Trematodiasis, Centro de Microbiología y Biología Celular, Instituto Venezolano de Investigaciones Científicas (IVIC), Caracas, Venezuela
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Schistosoma tegument proteins in vaccine and diagnosis development: an update. J Parasitol Res 2012; 2012:541268. [PMID: 23125917 PMCID: PMC3483795 DOI: 10.1155/2012/541268] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 09/24/2012] [Indexed: 01/16/2023] Open
Abstract
The development of a vaccine against schistosomiasis and also the availability of a more sensitive diagnosis test are important tools to help chemotherapy in controlling disease transmission. Bioinformatics tools, together with the access to parasite genome, published recently, should help generate new knowledge on parasite biology and search for new vaccines or therapeutic targets and antigens to be used in the disease diagnosis. Parasite surface proteins, especially those expressed in schistosomula tegument, represent interesting targets to be used in vaccine formulations and in the diagnosis of early infections, since the tegument represents the interface between host and parasite and its molecules are responsible for essential functions to parasite survival. In this paper we will present the advances in the development of vaccines and diagnosis tests achieved with the use of the information from schistosome genome focused on parasite tegument as a source for antigens.
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9
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Computational vaccinology: an important strategy to discover new potential S. mansoni vaccine candidates. J Biomed Biotechnol 2011; 2011:503068. [PMID: 22013383 PMCID: PMC3196198 DOI: 10.1155/2011/503068] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/12/2011] [Indexed: 11/17/2022] Open
Abstract
The flatworm Schistosoma mansoni is a blood fluke parasite that causes schistosomiasis, a debilitating disease that occurs throughout the developing world. Current schistosomiasis control strategies are mainly based on chemotherapy, but many researchers believe that the best long-term strategy to control schistosomiasis is through immunization with an antischistosomiasis vaccine combined with drug treatment. Several papers on Schistosoma mansoni vaccine and drug development have been published in the past few years, representing an important field of study. The advent of technologies that allow large-scale studies of genes and proteins had a remarkable impact on the screening of new and potential vaccine candidates in schistosomiasis. In this postgenomic scenario, bioinformatic technologies have emerged as important tools to mine transcriptomic, genomic, and proteomic databases. These new perspectives are leading to a new round of rational vaccine development. Herein, we discuss different strategies to identify potential S. mansoni vaccine candidates using computational vaccinology.
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10
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Sepulveda J, Tremblay JM, DeGnore JP, Skelly PJ, Shoemaker CB. Schistosoma mansoni host-exposed surface antigens characterized by sera and recombinant antibodies from schistosomiasis-resistant rats. Int J Parasitol 2010; 40:1407-17. [PMID: 20600071 DOI: 10.1016/j.ijpara.2010.04.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 04/07/2010] [Accepted: 04/09/2010] [Indexed: 01/02/2023]
Abstract
Antibodies from Schistosoma mansoni-infected rats, unlike mice, show a higher titer for schistosome apical tegumental antigens compared with non-apical membrane antigens. These antibodies bind to the surface of living lung-stage worms and to formaldehyde-fixed adult worms. We produced a single-chain antibody Fv domain (scFv) phage library displaying the antibody repertoire of rats highly immune to schistosome infection and we selected for scFvs that recognize the host-exposed surface of worms. Five unique rat scFvs (Teg1, Teg4, Teg5, Teg20 and Teg37) were obtained which recognize schistosome surface epitopes. Each of the scFvs recognizes the surface of living schistosomula and lung-stage schistosomules and/or the surface of formaldehyde-fixed adult worms. None of these scFvs reproducibly stained living adult worms. This suggests that a change occurs during the transition from lung schistosomules to 4-week adults such that at least some surface antigens, although remaining on the surface in living adult worms, can no longer be immunologically stained. Teg1 and Teg4 scFvs both recognize specific bands on Western blots. No bands were observed for the other three scFvs, suggesting that these scFvs may recognize non-protein or conformationally-dependent epitopes. Teg1 was unambiguously identified as recognizing the S. mansoni tetraspanin antigen, SmTSP-2, within the large extracellular domain. Teg4 recognizes a 35kDa band tentatively identified as Sm29 by proteomic analysis. These scFvs can now be used to characterize schistosome epitopes at the host-parasite interface, to target worms in vivo, and to study the mechanisms by which these worms naturally evade immune damage to the tegument within permissive hosts.
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Affiliation(s)
- Jorge Sepulveda
- Department of Biomedical Sciences, Tufts Cummings School of Veterinary Medicine, 200 Westboro Rd., North Grafton, MA 01536, USA
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11
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Gobert GN, Moertel L, Brindley PJ, McManus DP. Developmental gene expression profiles of the human pathogen Schistosoma japonicum. BMC Genomics 2009; 10:128. [PMID: 19320991 PMCID: PMC2670322 DOI: 10.1186/1471-2164-10-128] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Accepted: 03/25/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The schistosome blood flukes are complex trematodes and cause a chronic parasitic disease of significant public health importance worldwide, schistosomiasis. Their life cycle is characterised by distinct parasitic and free-living phases involving mammalian and snail hosts and freshwater. Microarray analysis was used to profile developmental gene expression in the Asian species, Schistosoma japonicum. Total RNAs were isolated from the three distinct environmental phases of the lifecycle -- aquatic/snail (eggs, miracidia, sporocysts, cercariae), juvenile (lung schistosomula and paired but pre-egg laying adults) and adult (paired, mature males and egg-producing females, both examined separately). Advanced analyses including ANOVA, principal component analysis, and hierarchal clustering provided a global synopsis of gene expression relationships among the different developmental stages of the schistosome parasite. RESULTS Gene expression profiles were linked to the major environmental settings through which the developmental stages of the fluke have to adapt during the course of its life cycle. Gene ontologies of the differentially expressed genes revealed a wide range of functions and processes. In addition, stage-specific, differentially expressed genes were identified that were involved in numerous biological pathways and functions including calcium signalling, sphingolipid metabolism and parasite defence. CONCLUSION The findings provide a comprehensive database of gene expression in an important human pathogen, including transcriptional changes in genes involved in evasion of the host immune response, nutrient acquisition, energy production, calcium signalling, sphingolipid metabolism, egg production and tegumental function during development. This resource should help facilitate the identification and prioritization of new anti-schistosome drug and vaccine targets for the control of schistosomiasis.
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Affiliation(s)
- Geoffrey N Gobert
- Division of Infectious Diseases & Immunology, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
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Interactions of Triton X-100 with sphingomyelin and phosphatidylcholine monolayers: influence of the cholesterol content. Colloids Surf B Biointerfaces 2008; 66:163-7. [PMID: 18644701 DOI: 10.1016/j.colsurfb.2008.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2008] [Revised: 06/04/2008] [Accepted: 06/09/2008] [Indexed: 11/21/2022]
Abstract
The presence of microdomains, called lipid rafts, in biological membranes is usually explained by lateral segregation between specific lipids and proteins. These rafts present similarities with the membrane domains isolated by their non-ionic detergent-resistance at 4 degrees C. They are enriched in sphingomyelin and cholesterol as compared with the outer leaflet of eukaryotic cell membranes. To understand the role played by the lipids enriched in rafts in their resistance to solubilization by detergents, the interactions between these lipids and the non-ionic detergent Triton X-100 were studied by using different lipid monolayers at the air-water interface. The influence of Triton X-100 on the Langmuir isotherms (i.e. surface pressure/area isotherms) of monolayers containing sphingomyelin and cholesterol at different mole ratios was analyzed and the results were compared with the influence of Triton X-100 on monolayers containing a phosphatidylcholine bearing a saturated and an unsaturated fatty acid (i.e. palmitoyloleylphosphatidylcholine) and cholesterol. This phosphatidylcholine was chosen since the phosphatidylcholines present in rafts isolated from bovine kidney could contain about 50% of saturated fatty acids. Triton X-100 induces an increase in the condensing effect observed as compared with ideal mixture of phospholipid/cholesterol. Triton X-100-induced changes in the morphology of the monolayers were visualized by Brewster angle microscopy, which confirmed the differences of behavior observed by analyzing the isotherms.
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Light and confocal microscopic observations of adult Schistosoma mansoni from mice fed on a high-fat diet. J Helminthol 2007; 81:361-8. [PMID: 17956644 DOI: 10.1017/s0022149x07799121] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The morphological aspects of Schistosoma mansoni adult worms recovered from albino mice fed on a cholesterol-rich diet compared to mice fed on a standard chow were investigated. After feeding on their respective diets for over a period of 5 months, mice were subcutaneously infected with c. 50 S. mansoni cercariae/mouse. Blood samples were obtained 1 day prior to experimental infections and 63 days later, when mice were euthanized by jugular section (hypovolaemic shock). Total cholesterol (TC) levels were determined. Recovered worms were stained with hydrochloric carmine, and preserved as whole-mounts for examination by bright-field and laser confocal microscopy. The infected mice fed on high-fat chow showed higher levels of serum lipoproteins than the infected mice fed on standard chow, except for very-low-density lipoprotein cholesterol (VLDL-c) and triglycerides (TG). In this experiment, worms from mice fed on a high-fat chow showed a greater percentage of morphological differentiation regarding supernumerary testes, seminal vesicle, and seminal receptacle. In mice of this group, the rate of oocyte laying in the ovary was much higher than in control females. The present results suggest that cholesterol could be actively involved in the modulation of cell signalling and reproduction, because the lobes contained fully developed oocytes in variable amounts, different from control males. The data presented here are the first to report the role of a cholesterol-rich diet affecting the development of S. mansoni worms.
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Kusel JR, Al-Adhami BH, Doenhoff MJ. The schistosome in the mammalian host: understanding the mechanisms of adaptation. Parasitology 2007; 134:1477-526. [PMID: 17572930 DOI: 10.1017/s0031182007002971] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
SUMMARYIn this review, we envisage the host environment, not as a hostile one, since the schistosome thrives there, but as one in which the relationship between the two organisms consists of constant communication, through signalling mechanisms involving sense organs, surface glycocalyx, surface membrane and internal organs of the parasite, with host fluids and cells. The surface and secretions of the schistosome egg have very different properties from those of other parasite stages, but adapted for the dispersal of the eggs and for the preservation of host liver function. We draw from studies of mammalian cells and other organisms to indicate how further work might be carried out on the signalling function of the surface glycocalyx, the raft structure of the surface and existence of pores in the surface membrane, the repair of the surface membrane, the role of the membrane structure in ion channel function (including recent work on the actin cytoskeleton and calcium channels) and the possible role of P-glycoproteins in the adaptation of the parasite to its environment. We are speculative in some areas, such as the suggestions that variability in surface properties of schistosomes may relate to the existence of membrane rafts and that parasite communities may exhibit quorum sensing. This speculative approach is adopted with the hope that future work on the whole organisms and their interactions will be encouraged.
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Affiliation(s)
- J R Kusel
- Glasgow Biomedical Research Centre, University of Glasgow, Glasgow G12 8TA, UK.
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15
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Loukas A, Tran M, Pearson MS. Schistosome membrane proteins as vaccines. Int J Parasitol 2006; 37:257-63. [PMID: 17222846 DOI: 10.1016/j.ijpara.2006.12.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 11/28/2006] [Accepted: 12/03/2006] [Indexed: 01/08/2023]
Abstract
Schistosomes are parasitic blood flukes that infect approximately 200 million people and are arguably the most important human helminth in terms of mortality. The outermost surface of intra-mammalian stages of the parasite, the tegument, is the key to the parasite's success, but it is also generally viewed as the most susceptible target for vaccines and drugs. Over the past 2 years the proteome of the Schistosoma mansoni tegument has been investigated and these studies revealed surprisingly few proteins that are predicted to be accessible to the host immune response, namely proteins with at least one membrane-spanning domain. However, of this handful of proteins, some are showing great promise as recombinant vaccines against schistosomiasis at a pre-clinical level. In particular, the tetraspanin family of integral membrane proteins appears to be abundantly represented in the tegument, and convergent data using the mouse vaccine model and correlates of protective immunity in naturally exposed people suggests that this family of membrane proteins offer great promise for schistosomiasis vaccines. With the recent advances in schistosome genomics and proteomics, a new suite of potential vaccine antigens are presented and these warrant detailed investigation and appropriate funding over the next few years.
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Affiliation(s)
- Alex Loukas
- Helminth Biology Laboratory, Division of Infectious Diseases and Immunology, Queensland Institute of Medical Research Brisbane, Qld 4006, Australia.
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Abstract
The syncytial cytoplasmic layer, termed the tegument, which covers the entire surface of adult schistosomes, is a major interface between the parasite and its host. Since schistosomes can survive for decades within the host bloodstream, they are clearly able to evade host immune responses, and their ability is dependent on the properties of the tegument surface. We review here the molecular organization and biochemical functions of the tegument, combining the extensive literature over the last three decades with recent proteomic studies. We have interpreted the organization of the tegument surface as bounded by a conventional plasma membrane overlain by a membrane-like secretion, the membranocalyx, with which host molecules can associate. The range of parasite proteins, glycans and lipids found in the surface complex is evaluated, together with the host molecules detected. We consider the way in which the tegument surface is formed after cercarial penetration into the skin, and changes that occur as parasites develop to maturity. Lastly, we review the evidence on surface dynamics and turnover.
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Affiliation(s)
- Patrick J Skelly
- Tufts Cummings School of Veterinary Medicine, Department of Biomedical Sciences, 20 Westboro Road, North Grafton, MA 01536, USA
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Thors C, Jokiranta TS, Meri T, Kairemo K, Meri S, Linder E. Immunoglobulin uptake and processing by Schistosoma mansoni. Parasite Immunol 2006; 28:421-8. [PMID: 16916365 DOI: 10.1111/j.1365-3024.2006.00839.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intravascular Schistosoma mansoni worms seem to take up immunoglobulins from blood by surface Fc-receptors, but the process whereby bound immunoglobulins are processed by the parasite is poorly understood. We here present morphological data suggesting that two distinct main processes are involved: Host immunoglobulins were seen at two distinct locations in the parasite: in the frontal part of the enteric tube, the oesophagus, and as a fine granular staining at the surface and in the subtegumental region. The latter staining pattern corresponds to host immunoglobulin localization in discrete organelle-like aggregates tentatively identified as 'discoid or elongate bodies' at the ultrastructural level using immunogold staining. Immunoglobulin uptake by intravascular worms was also demonstrated in vivo after passive administration of 125I-labelled rabbit and mouse immunoglobulins. Radiolabelled immunoglobulins were taken up by the worms and shown to localize as fine strands running perpendicular to the parasite surface. Our results suggest that intravascular schistosomes take up host immunoglobulins both as part of their enteric digestion and by a surface Fc-receptor-mediated mechanism, involving transport and processing within organelles, 'elongate bodies'. Immunoglobulins taken up by intravascular schistosomes form a distinct organelle-like granules, which seem to be processed within the excretory system of the parasite.
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Affiliation(s)
- C Thors
- Swedish Institute for Infectious Disease Control (SMI), Solna, Sweden
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18
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Jones MK, Gobert GN, Zhang L, Sunderland P, McManus DP. The cytoskeleton and motor proteins of human schistosomes and their roles in surface maintenance and host-parasite interactions. Bioessays 2004; 26:752-65. [PMID: 15221857 DOI: 10.1002/bies.20058] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Schistosomes are parasitic blood flukes, responsible for significant human disease in tropical and developing nations. Here we review information on the organization of the cytoskeleton and associated motor proteins of schistosomes, with particular reference to the organization of the syncytial tegument, a unique cellular adaptation of these and other neodermatan flatworms. Extensive EST databases show that the molecular constituents of the cytoskeleton and associated molecular systems are likely to be similar to those of other eukaryotes, although there are potentially some molecules unique to schistosomes and platyhelminths. The biology of some components, particular those contributing to host-parasite interactions as well as chemotherapy and immunotherapy are discussed. Unresolved questions in relation to the structure and function of the tegument relate to dynamic organization of the syncytial layer.
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Affiliation(s)
- Malcolm K Jones
- Queensland Institute of Medical Research, Herston, Queensland, Australia.
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19
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Gobert GN, Stenzel DJ, McManus DP, Jones MK. The ultrastructural architecture of the adult Schistosoma japonicum tegument. Int J Parasitol 2004; 33:1561-75. [PMID: 14636672 DOI: 10.1016/s0020-7519(03)00255-8] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The tegument of the adult blood fluke Schistosoma japonicum is in direct contact with the host blood and immune systems. A comprehensive understanding of the ultrastructure of the tegument is crucial to the understanding of how the parasite maintains itself within the mammalian host. Important functions such as nutritional uptake and immune evasion are suspected functions of the tegument and this review discusses these aspects and presents some insights into some of these crucial functions. Transmission electron microscopy has allowed the identification of ultrastructural features of the adult S. japonicum, some of which differ from the reported features of other schistosome species. Morphological differences within the tegument of the adult S. japonicum are noted between sexes, among different regions of the worms and between aspects along the length of the parasite. Differences included variations in the ultrastructure, size and number of tegumental bodies and mitochondria within the matrix, and differences in the relative area of the apical surface of the tegument. Functions of the various components of the tegument matrix and specialised functions of different regions of the male and female parasites are discussed based on ultrastructural findings and previously reported biochemical and molecular data.
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Affiliation(s)
- Geoffrey N Gobert
- Molecular Parasitology Laboratory, Division of Infectious Diseases and Immunology, Queensland Institute of Medical Research, Royal Brisbane Hospital Post Office, Herston, Queensland 4006, Australia.
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Verjovski-Almeida S, DeMarco R, Martins EAL, Guimarães PEM, Ojopi EPB, Paquola ACM, Piazza JP, Nishiyama MY, Kitajima JP, Adamson RE, Ashton PD, Bonaldo MF, Coulson PS, Dillon GP, Farias LP, Gregorio SP, Ho PL, Leite RA, Malaquias LCC, Marques RCP, Miyasato PA, Nascimento ALTO, Ohlweiler FP, Reis EM, Ribeiro MA, Sá RG, Stukart GC, Soares MB, Gargioni C, Kawano T, Rodrigues V, Madeira AMBN, Wilson RA, Menck CFM, Setubal JC, Leite LCC, Dias-Neto E. Transcriptome analysis of the acoelomate human parasite Schistosoma mansoni. Nat Genet 2003; 35:148-57. [PMID: 12973350 DOI: 10.1038/ng1237] [Citation(s) in RCA: 368] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Accepted: 08/17/2003] [Indexed: 11/09/2022]
Abstract
Schistosoma mansoni is the primary causative agent of schistosomiasis, which affects 200 million individuals in 74 countries. We generated 163,000 expressed-sequence tags (ESTs) from normalized cDNA libraries from six selected developmental stages of the parasite, resulting in 31,000 assembled sequences and 92% sampling of an estimated 14,000 gene complement. By analyzing automated Gene Ontology assignments, we provide a detailed view of important S. mansoni biological systems, including characterization of metazoa-specific and eukarya-conserved genes. Phylogenetic analysis suggests an early divergence from other metazoa. The data set provides insights into the molecular mechanisms of tissue organization, development, signaling, sexual dimorphism, host interactions and immune evasion and identifies novel proteins to be investigated as vaccine candidates and potential drug targets.
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Affiliation(s)
- Sergio Verjovski-Almeida
- Departamento de Bioquimica, Instituto de Quimica, Universidade de São Paulo, 05508-900 São Paulo, SP, Brazil.
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21
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Harris J, Werling D, Hope JC, Taylor G, Howard CJ. Caveolae and caveolin in immune cells: distribution and functions. Trends Immunol 2002; 23:158-64. [PMID: 11864845 DOI: 10.1016/s1471-4906(01)02161-5] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Caveolae are small, cholesterol-rich, hydrophobic membrane domains, characterized by the presence of the protein caveolin and involved in several cellular processes, including clathrin-independent endocytosis, the regulation and transport of cellular cholesterol, and signal transduction. Recently, caveolae have been identified as providing a novel route by which several pathogens are internalized by antigen-presenting cells and as centers for signal transduction. Here, we review the distribution and role of caveolae and caveolin in mammalian immune cells.
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Affiliation(s)
- James Harris
- Sir William Dunn School of Pathology, South Parks Road, OX1 3RE, Oxford, UK.
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22
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Abstract
Male and female schistosomes are permanently paired while they live in the bloodstream of their vertebrate hosts. Female schistosomes produce eggs only when they are in intimate association with a male. Here, I combine classical cytological knowledge about the cellular processes in the female that are affected by the male with recent molecular results that are beginning to allow speculation about the signalling events involved.
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Affiliation(s)
- W Kunz
- Genetic Parasitology Group, Institute of Genetics, Heinrich-Heine University, Universitätsstr. 1, D-40225, Düsseldorf, Germany.
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Davies SJ, Pearce EJ. Atypical post-translational modification and targeting of a Schistosoma mansoni surface receptor, a member of the transforming growth factor beta receptor family of cell surface receptors. Mol Biochem Parasitol 1999; 104:299-310. [PMID: 10593183 DOI: 10.1016/s0166-6851(99)00147-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The surface membrane of the intravascular parasite Schistosoma mansoni is composed of not one but two closely apposed lipid bilayers which overlie a syncytial cellular layer, known as the tegument or neodermis. To gain insights into how membrane proteins are transported to and displayed on this unusual surface structure, we have investigated the post-translational modification and targeting of SmRK-1, a receptor and type I membrane protein expressed on the parasite surface, using heterologous expression systems. While SmRK-1 enters the secretory pathway in these systems, our data indicate that the SmRK-1 N-terminal signal peptide is either not cleaved by signal peptidase or is only eleven amino acids long or less. Retention of the signal peptide is accompanied by N-linked glycosylation of an asparagine residue within the predicted signal peptide. The SmRK-1 signal peptide is not capable of directing another cytoplasmic protein to the secretory pathway, suggesting that the signal for insertion of the SmRK-1 extracellular domain into the endoplasmic reticulum resides elsewhere in the protein. Further, SmRK-1 is inefficiently transported to the cell surface in mammalian cells, suggesting that the schistosome neodermis possesses specialized systems for receptor targeting and localization.
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Affiliation(s)
- S J Davies
- Department of Microbiology and Immunology, College of Veterinary Medicine, Cornell Unirersity, Ithaca, NY 14t53, USA
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