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Mollusc N-glycosylation: Structures, Functions and Perspectives. Biomolecules 2021; 11:biom11121820. [PMID: 34944464 PMCID: PMC8699351 DOI: 10.3390/biom11121820] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/01/2021] [Accepted: 12/01/2021] [Indexed: 12/22/2022] Open
Abstract
Molluscs display a sophisticated N-glycan pattern on their proteins, which is, in terms of involved structural features, even more diverse than that of vertebrates. This review summarises the current knowledge of mollusc N-glycan structures, with a focus on the functional aspects of the corresponding glycoproteins. Furthermore, the potential of mollusc-derived biomolecules for medical applications is addressed, emphasising the importance of mollusc research.
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Skála V, Walker AJ, Horák P. Snail defence responses to parasite infection: The Lymnaea stagnalis-Trichobilharzia szidati model. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2020; 102:103464. [PMID: 31402190 DOI: 10.1016/j.dci.2019.103464] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 08/01/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
Lymnaea stagnalis is a common freshwater gastropod. Importantly, the snail serves as the intermediate host for more than one hundred species of digenetic trematodes, including the avian schistosome Trichobilharzia szidati, a causative agent of cercarial dermatitis in humans. Infection of L. stagnalis by T. szidati initiates a dynamic confrontation between the host and the parasite that culminates in immunocompatibility ensuring survival and development of larvae. Unfortunately, the molecular mechanisms determining this immunocompatibility remain poorly characterised. By employing a variety of immune elicitors, including chemical compounds, PAMPs and bacteria, research in the last two decades has elucidated some of the molecular processes that regulate the snail internal defence response such as haemocyte signalling pathways. These discoveries provide a framework for future studies of molecular interactions between T. szidati and L. stagnalis to help elucidate factors and mechanisms enabling transmission of schistosome parasites. Moreover, support from recently available next generation sequence data and CRISPR-enabled functional genomics should further enable L. stagnalis as an important model for comparative immunology and contribute to a more comprehensive understanding of immune functions in gastropod molluscs.
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Affiliation(s)
- Vladimír Skála
- General University Hospital and the First Faculty of Medicine of Charles University, Institute of Medical Biochemistry and Laboratory Diagnostics, Prague, Czech Republic; Charles University, First Faculty of Medicine, Institute of Immunology and Microbiology, Prague, Czech Republic.
| | - Anthony J Walker
- Kingston University, Molecular Parasitology Laboratory, School of Life Sciences Pharmacy and Chemistry, Kingston upon Thames, Surrey, United Kingdom
| | - Petr Horák
- Charles University, Faculty of Science, Department of Parasitology, Prague, Czech Republic
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Skála V, Walker AJ, Horák P. Extracellular trap-like fiber release may not be a prominent defence response in snails: evidence from three species of freshwater gastropod molluscs. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2018; 79:137-141. [PMID: 29069574 DOI: 10.1016/j.dci.2017.10.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/18/2017] [Accepted: 10/19/2017] [Indexed: 06/07/2023]
Abstract
The discovery that mammalian neutrophils generate extracellular chromatin fibers that entrap/kill bacteria supported a new paradigm for innate immunity in animals. Similar findings in other models across diverse taxa have led to the hypothesis that the phenomenon is ancient and evolutionary conserved. Here, using a variety of synthetic (e.g. peptidoglycan) and biological (e.g. trematode larvae) components to investigate extracellular trap-like (ET-like) fiber production in vitro by haemocytes of Lymnaea stagnalis, Radix lagotis and Planorbarius corneus snails, ET-like fibers were rarely observed. We suggest, therefore, that ET-like fibers play a marginal role in defence of these snail species and thus the fiber production may not be a critical process underpinning immunity in all invertebrate species.
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Affiliation(s)
- Vladimír Skála
- Charles University, Faculty of Science, Department of Parasitology, Prague, Czech Republic; Charles University, First Faculty of Medicine, Institute of Immunology and Microbiology, Prague, Czech Republic.
| | - Anthony J Walker
- Kingston University, School of Life Sciences, Pharmacy and Chemistry, Molecular Parasitology Laboratory, Kingston Upon Thames, Surrey, United Kingdom
| | - Petr Horák
- Charles University, Faculty of Science, Department of Parasitology, Prague, Czech Republic
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Belavgeni A, Dailianis S. The role of phosphatidylinositol-3-OH-kinase (PI3-kinase) and respiratory burst enzymes in the [omim][BF 4]-mediated toxic mode of action in mussel hemocytes. FISH & SHELLFISH IMMUNOLOGY 2017; 68:144-153. [PMID: 28698124 DOI: 10.1016/j.fsi.2017.07.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 06/12/2017] [Accepted: 07/08/2017] [Indexed: 06/07/2023]
Abstract
The present study investigates the role of phosphatidylinositol-3-OH-kinase (PI3-kinase) and respiratory burst enzymes, NADPH oxidase and NO synthase, in the 1-methyl-3-octylimidazolium tetrafluoroborate ([omim][BF4])-mediated toxic mode of action in mussel hemocytes. Specifically, cell viability (using the neutral red uptake assay) was primarily tested in hemocytes treated with different concentrations of [omim][BF4] (0.1-10 mg L-1) and thereafter [omim][BF4]-mediated oxidative (in terms of superoxide anions/O2- and nitric oxide/NO generation, as well as the enhancement of lipid peroxidation by-products, in terms of malondialdehyde/MDA) and genotoxic (in terms of DNA damage) effects were determined in hemocytes treated with 1 mg L-1 [omim][BF4]. Moreover, in order to investigate, even indirectly and non-entirely specific, the role of PI3-kinase, NADPH oxidase and NO synthase, the [omim][BF4]-mediated effects were also investigated in hemocytes pre-incubated with wortmannin (50 nM), diphenyleneiodonium chloride (DPI 10 μM) and NG-nitro-l-arginine methyl ester (l-NAME 10 μM), respectively. The results showed that [omim][BF4] ability to enhance O2-, NO, MDA and DNA damage, via its interaction with cellular membranes, was significantly attenuated in the presence of each inhibitor in almost all cases. The current findings revealed for the first time that certain signaling molecules, such as PI3-kinase, as well as respiratory burst enzymes activation, such as NADPH oxidase and NO synthase, could merely attribute to the [omim][BF4]-mediated mode of action, thus enriching our knowledge for the molecular mechanisms of ILs toxicity.
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Affiliation(s)
- Alexia Belavgeni
- Section of Animal Biology, Department of Biology, Faculty of Sciences, University of Patras, Patras GR-26 500, Greece
| | - Stefanos Dailianis
- Section of Animal Biology, Department of Biology, Faculty of Sciences, University of Patras, Patras GR-26 500, Greece.
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Zukaite V, Cook RT, Walker AJ. Multiple roles for protein kinase C in gastropod embryogenesis. Cell Tissue Res 2015; 364:117-24. [DOI: 10.1007/s00441-015-2288-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 08/27/2015] [Indexed: 02/06/2023]
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Horák P, Mikeš L, Lichtenbergová L, Skála V, Soldánová M, Brant SV. Avian schistosomes and outbreaks of cercarial dermatitis. Clin Microbiol Rev 2015; 28:165-90. [PMID: 25567226 PMCID: PMC4284296 DOI: 10.1128/cmr.00043-14] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cercarial dermatitis (swimmer's itch) is a condition caused by infective larvae (cercariae) of a species-rich group of mammalian and avian schistosomes. Over the last decade, it has been reported in areas that previously had few or no cases of dermatitis and is thus considered an emerging disease. It is obvious that avian schistosomes are responsible for the majority of reported dermatitis outbreaks around the world, and thus they are the primary focus of this review. Although they infect humans, they do not mature and usually die in the skin. Experimental infections of avian schistosomes in mice show that in previously exposed hosts, there is a strong skin immune reaction that kills the schistosome. However, penetration of larvae into naive mice can result in temporary migration from the skin. This is of particular interest because the worms are able to migrate to different organs, for example, the lungs in the case of visceral schistosomes and the central nervous system in the case of nasal schistosomes. The risk of such migration and accompanying disorders needs to be clarified for humans and animals of interest (e.g., dogs). Herein we compiled the most comprehensive review of the diversity, immunology, and epidemiology of avian schistosomes causing cercarial dermatitis.
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Affiliation(s)
- Petr Horák
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Libor Mikeš
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Lucie Lichtenbergová
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Vladimír Skála
- Department of Parasitology, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Miroslava Soldánová
- Institute of Parasitology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - Sara Vanessa Brant
- Museum Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, New Mexico, USA
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Skála V, Černíková A, Jindrová Z, Kašný M, Vostrý M, Walker AJ, Horák P. Influence of Trichobilharzia regenti (Digenea: Schistosomatidae) on the defence activity of Radix lagotis (Lymnaeidae) Haemocytes. PLoS One 2014; 9:e111696. [PMID: 25372492 PMCID: PMC4221104 DOI: 10.1371/journal.pone.0111696] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Accepted: 10/07/2014] [Indexed: 11/29/2022] Open
Abstract
Radix lagotis is an intermediate snail host of the nasal bird schistosome Trichobilharzia regenti. Changes in defence responses in infected snails that might be related to host-parasite compatibility are not known. This study therefore aimed to characterize R. lagotis haemocyte defence mechanisms and determine the extent to which they are modulated by T. regenti. Histological observations of R. lagotis infected with T. regenti revealed that early phases of infection were accompanied by haemocyte accumulation around the developing larvae 2–36 h post exposure (p.e.) to the parasite. At later time points, 44–92 h p.e., no haemocytes were observed around T. regenti. Additionally, microtubular aggregates likely corresponding to phagocytosed ciliary plates of T. regenti miracidia were observed within haemocytes by use of transmission electron microscopy. When the infection was in the patent phase, haemocyte phagocytic activity and hydrogen peroxide production were significantly reduced in infected R. lagotis when compared to uninfected counterparts, whereas haemocyte abundance increased in infected snails. At a molecular level, protein kinase C (PKC) and extracellular-signal regulated kinase (ERK) were found to play an important role in regulating these defence reactions in R. lagotis. Moreover, haemocytes from snails with patent infection displayed lower PKC and ERK activity in cell adhesion assays when compared to those from uninfected snails, which may therefore be related to the reduced defence activities of these cells. These data provide the first integrated insight into the immunobiology of R. lagotis and demonstrate modulation of haemocyte-mediated responses in patent T. regenti infected snails. Given that immunomodulation occurs during patency, interference of snail-host defence by T. regenti might be important for the sustained production and/or release of infective cercariae.
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Affiliation(s)
- Vladimír Skála
- Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic
- * E-mail:
| | - Alena Černíková
- Charles University in Prague, Faculty of Science, Institute of Applied Mathematics and Information Technologies, Prague, Czech Republic
| | - Zuzana Jindrová
- Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic
- Charles University in Prague, 1st Faculty of Medicine, Institute of Immunology and Microbiology, Prague, Czech Republic
| | - Martin Kašný
- Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic
- Masaryk University, Faculty of Science, Department of Botany and Zoology, Brno, Czech Republic
| | - Martin Vostrý
- Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic
- Institute of Haematology and Blood Transfusion, Prague, Czech Republic
| | - Anthony J. Walker
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
| | - Petr Horák
- Charles University in Prague, Faculty of Science, Department of Parasitology, Prague, Czech Republic
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Walker AJ, Ressurreição M, Rothermel R. Exploring the function of protein kinases in schistosomes: perspectives from the laboratory and from comparative genomics. Front Genet 2014; 5:229. [PMID: 25132840 PMCID: PMC4117187 DOI: 10.3389/fgene.2014.00229] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 06/30/2014] [Indexed: 01/09/2023] Open
Abstract
Eukaryotic protein kinases are well conserved through evolution. The genome of Schistosoma mansoni, which causes intestinal schistosomiasis, encodes over 250 putative protein kinases with all of the main eukaryotic groups represented. However, unraveling functional roles for these kinases is a considerable endeavor, particularly as protein kinases regulate multiple and sometimes overlapping cell and tissue functions in organisms. In this article, elucidating protein kinase signal transduction and function in schistosomes is considered from the perspective of the state-of-the-art methodologies used and comparative organismal biology, with a focus on current advances and future directions. Using the free-living nematode Caenorhabditis elegans as a comparator we predict roles for various schistosome protein kinases in processes vital for host invasion and successful parasitism such as sensory behavior, growth and development. It is anticipated that the characterization of schistosome protein kinases in the context of parasite function will catalyze cutting edge research into host-parasite interactions and will reveal new targets for developing drug interventions against human schistosomiasis.
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Affiliation(s)
- Anthony J Walker
- Laboratory of Molecular Parasitology, School of Life Sciences, Kingston University Kingston upon Thames, UK
| | - Margarida Ressurreição
- Laboratory of Molecular Parasitology, School of Life Sciences, Kingston University Kingston upon Thames, UK
| | - Rolf Rothermel
- Laboratory of Molecular Parasitology, School of Life Sciences, Kingston University Kingston upon Thames, UK
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Ressurreição M, De Saram P, Kirk RS, Rollinson D, Emery AM, Page NM, Davies AJ, Walker AJ. Protein kinase C and extracellular signal-regulated kinase regulate movement, attachment, pairing and egg release in Schistosoma mansoni. PLoS Negl Trop Dis 2014; 8:e2924. [PMID: 24921927 PMCID: PMC4055629 DOI: 10.1371/journal.pntd.0002924] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 04/19/2014] [Indexed: 01/22/2023] Open
Abstract
Protein kinases C (PKCs) and extracellular signal-regulated kinases (ERKs) are evolutionary conserved cell signalling enzymes that coordinate cell function. Here we have employed biochemical approaches using ‘smart’ antibodies and functional screening to unravel the importance of these enzymes to Schistosoma mansoni physiology. Various PKC and ERK isotypes were detected, and were differentially phosphorylated (activated) throughout the various S. mansoni life stages, suggesting isotype-specific roles and differences in signalling complexity during parasite development. Functional kinase mapping in adult worms revealed that activated PKC and ERK were particularly associated with the adult male tegument, musculature and oesophagus and occasionally with the oesophageal gland; other structures possessing detectable activated PKC and/or ERK included the Mehlis' gland, ootype, lumen of the vitellaria, seminal receptacle and excretory ducts. Pharmacological modulation of PKC and ERK activity in adult worms using GF109203X, U0126, or PMA, resulted in significant physiological disturbance commensurate with these proteins occupying a central position in signalling pathways associated with schistosome muscular activity, neuromuscular coordination, reproductive function, attachment and pairing. Increased activation of ERK and PKC was also detected in worms following praziquantel treatment, with increased signalling associated with the tegument and excretory system and activated ERK localizing to previously unseen structures, including the cephalic ganglia. These findings support roles for PKC and ERK in S. mansoni homeostasis, and identify these kinase groups as potential targets for chemotherapeutic treatments against human schistosomiasis, a neglected tropical disease of enormous public health significance. Parasitic blood flukes, also called schistosomes, cause human schistosomiasis, a neglected tropical disease and major public health problem in developing countries, especially sub-Saharan Africa. Sustainable control of schistosomiasis is difficult, mainly because the complex life cycle of the parasite involves a freshwater snail host, and the ability of the parasite to evade the immune response of the human host and to survive for many years. Little is yet known about the cellular mechanisms in schistosomes and how they regulate parasite homeostasis, development and behaviour. In this paper, the nature of intracellular signalling by protein kinases C (PKCs) and extracellular signal-regulated kinases (ERKs) in schistosomes is studied and these proteins are found to be vital for the coordination of processes fundamental to parasite survival, such as muscular activity and reproductive function. Our results contribute to an understanding of molecular events regulating schistosome function and identify PKCs and ERKs as possible targets for the development of new chemotherapeutic treatments against schistosomiasis.
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Affiliation(s)
- Margarida Ressurreição
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
- Wolfson Wellcome Biomedical Laboratories, Life Sciences Department, Natural History Museum, London, United Kingdom
| | - Paulu De Saram
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
- Wolfson Wellcome Biomedical Laboratories, Life Sciences Department, Natural History Museum, London, United Kingdom
| | - Ruth S. Kirk
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Life Sciences Department, Natural History Museum, London, United Kingdom
| | - Aidan M. Emery
- Wolfson Wellcome Biomedical Laboratories, Life Sciences Department, Natural History Museum, London, United Kingdom
| | - Nigel M. Page
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
| | - Angela J. Davies
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
| | - Anthony J. Walker
- Molecular Parasitology Laboratory, School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, United Kingdom
- * E-mail:
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Abstract
In vitro cell culture systems from molluscs have significantly contributed to our basic understanding of complex physiological processes occurring within or between tissue-specific cells, yielding information unattainable using intact animal models. In vitro cultures of neuronal cells from gastropods show how simplified cell models can inform our understanding of complex networks in intact organisms. Primary cell cultures from marine and freshwater bivalve and gastropod species are used as biomonitors for environmental contaminants, as models for gene transfer technologies, and for studies of innate immunity and neoplastic disease. Despite efforts to isolate proliferative cell lines from molluscs, the snail Biomphalaria glabrata Say, 1818 embryonic (Bge) cell line is the only existing cell line originating from any molluscan species. Taking an organ systems approach, this review summarizes efforts to establish molluscan cell cultures and describes the varied applications of primary cell cultures in research. Because of the unique status of the Bge cell line, an account is presented of the establishment of this cell line, and of how these cells have contributed to our understanding of snail host-parasite interactions. Finally, we detail the difficulties commonly encountered in efforts to establish cell lines from molluscs and discuss how these difficulties might be overcome.
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Affiliation(s)
- T P Yoshino
- Department of Pathobiological Sciences, University of Wisconsin, School of Veterinary Medicine, Madison, WI 53706
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11
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Franzellitti S, Fabbri E. Cyclic-AMP mediated regulation of ABCB mRNA expression in mussel haemocytes. PLoS One 2013; 8:e61634. [PMID: 23593491 PMCID: PMC3625153 DOI: 10.1371/journal.pone.0061634] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 03/11/2013] [Indexed: 11/29/2022] Open
Abstract
Background The multixenobiotic resistance system (MXR) allows aquatic organisms to cope with their habitat despite high pollution levels by over-expressing membrane and intracellular transporters, including the P-glycoprotein (Pgp). In mammals transcription of the ABCB1 gene encoding Pgp is under cAMP/PKA-mediated regulation; whether this is true in mollusks is not fully clarified. Methodology/Principal Findings cAMP/PKA regulation and ABCB mRNA expression were assessed in haemocytes from Mediterranean mussels (Mytilus galloprovincialis) exposed in vivo for 1 week to 0.3 ng/L fluoxetine (FX) alone or in combination with 0.3 ng/L propranolol (PROP). FX significantly decreased cAMP levels and PKA activity, and induced ABCB mRNA down-regulation. FX effects were abolished in the presence of PROP. In vitro experiments using haemocytes treated with physiological agonists (noradrenaline and serotonin) and pharmacological modulators (PROP, forskolin, dbcAMP, and H89) of the cAMP/PKA system were performed to obtain clear evidence about the involvement of the signaling pathway in the transcriptional regulation of ABCB. Serotonin (5-HT) decreased cAMP levels, PKA activity and ABCB mRNA expression but increased the mRNA levels for a putative 5-HT1 receptor. Interestingly, 5-HT1 was also over-expressed after in vivo exposures to FX. 5-HT effects were counteracted by PROP. Forskolin and dbcAMP increased PKA activity as well as ABCB mRNA expression; the latter effect was abolished in the presence of the PKA inhibitor H89. Conclusions This study provides the first direct evidence for the cAMP/PKA-mediated regulation of ABCB transcription in mussels.
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MESH Headings
- 5' Untranslated Regions/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Animals
- Bucladesine/pharmacology
- Colforsin/pharmacology
- Cyclic AMP/pharmacology
- Cyclic AMP-Dependent Protein Kinases/antagonists & inhibitors
- Cyclic AMP-Dependent Protein Kinases/metabolism
- Fluoxetine/pharmacology
- Gene Expression Regulation/drug effects
- Hemocytes/drug effects
- Hemocytes/metabolism
- Humans
- Isoquinolines/pharmacology
- Models, Biological
- Mytilus/drug effects
- Mytilus/enzymology
- Mytilus/genetics
- Norepinephrine/pharmacology
- Promoter Regions, Genetic/genetics
- Propranolol/pharmacology
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Receptors, Serotonin, 5-HT1/genetics
- Receptors, Serotonin, 5-HT1/metabolism
- Sequence Analysis, DNA
- Serotonin/metabolism
- Serotonin Receptor Agonists/pharmacology
- Signal Transduction/drug effects
- Signal Transduction/genetics
- Sulfonamides/pharmacology
- Up-Regulation/drug effects
- Up-Regulation/genetics
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Affiliation(s)
- Silvia Franzellitti
- Interdepartment Centre for Environmental Science Research, University of Bologna, Ravenna, Italy.
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12
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Staudacher E. Methylation--an uncommon modification of glycans. Biol Chem 2013; 393:675-85. [PMID: 22944672 DOI: 10.1515/hsz-2012-0132] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 03/27/2012] [Indexed: 11/15/2022]
Abstract
A methyl (Me) group on a sugar residue is a rarely reported event. Until now, this type of modification has been found in the animal kingdom only in worms and molluscs, whereas it is more frequently present in some species of bacteria, fungi, algae and plants, but not in mammals. The monosaccharides involved as well as the positions of the Me groups on the sugar vary with species. Methylation appears to play a role in some recognition events, but details are still unknown. This review summarises the current knowledge on methylation of sugars in all types of organism.
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Affiliation(s)
- Erika Staudacher
- Department of Chemistry, University of Natural Resources and Life Sciences, Muthgasse 18, A-1190 Vienna, Austria.
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13
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Lockyer AE, Emery AM, Kane RA, Walker AJ, Mayer CD, Mitta G, Coustau C, Adema CM, Hanelt B, Rollinson D, Noble LR, Jones CS. Early differential gene expression in haemocytes from resistant and susceptible Biomphalaria glabrata strains in response to Schistosoma mansoni. PLoS One 2012; 7:e51102. [PMID: 23300533 PMCID: PMC3530592 DOI: 10.1371/journal.pone.0051102] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Accepted: 10/31/2012] [Indexed: 01/01/2023] Open
Abstract
The outcome of infection in the host snail Biomphalaria glabrata with the digenean parasite Schistosoma mansoni is determined by the initial molecular interplay occurring between them. The mechanisms by which schistosomes evade snail immune recognition to ensure survival are not fully understood, but one possibility is that the snail internal defence system is manipulated by the schistosome enabling the parasite to establish infection. This study provides novel insights into the nature of schistosome resistance and susceptibility in B. glabrata at the transcriptomic level by simultaneously comparing gene expression in haemocytes from parasite-exposed and control groups of both schistosome-resistant and schistosome-susceptible strains, 2 h post exposure to S. mansoni miracidia, using an novel 5K cDNA microarray. Differences in gene expression, including those for immune/stress response, signal transduction and matrix/adhesion genes were identified between the two snail strains and tests for asymmetric distributions of gene function also identified immune-related gene expression in resistant snails, but not in susceptible. Gene set enrichment analysis revealed that genes involved in mitochondrial electron transport, ubiquinone biosynthesis and electron carrier activity were consistently up-regulated in resistant snails but down-regulated in susceptible. This supports the hypothesis that schistosome-resistant snails recognize schistosomes and mount an appropriate defence response, while in schistosome-susceptible snails the parasite suppresses this defence response, early in infection.
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Affiliation(s)
- Anne E. Lockyer
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, The Natural History Museum, London, United Kingdom
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Aidan M. Emery
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, The Natural History Museum, London, United Kingdom
| | - Richard A. Kane
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, The Natural History Museum, London, United Kingdom
| | - Anthony J. Walker
- School of Life Sciences, Kingston University, Kingston-upon-Thames, Surrey, United Kingdom
| | - Claus D. Mayer
- BioSS (Biomathematics & Statistics Scotland) Office, Rowett Institute of Nutrition and Health, Aberdeen University, Aberdeen, United Kingdom
| | - Guillaume Mitta
- Ecologie et Evolution des interactions, CNRS Université de Perpignan, Perpignan, France
| | - Christine Coustau
- Sophia Agrobiotech Institute, INRA-CNRS-UNS, 06903 Sophia Antopolis, France
| | - Coen M. Adema
- CETI (Center for Evolutionary and Theoretical Immunology), Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - Ben Hanelt
- CETI (Center for Evolutionary and Theoretical Immunology), Biology, University of New Mexico, Albuquerque, New Mexico, United States of America
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Life Sciences, The Natural History Museum, London, United Kingdom
| | - Leslie R. Noble
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Catherine S. Jones
- School of Biological Sciences, University of Aberdeen, Aberdeen, United Kingdom
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Vouras C, Dailianis S. Evidence for phosphatidylinositol-3-OH-kinase (PI3-kinase) involvement in Cd-mediated oxidative effects on hemocytes of mussels. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:587-93. [PMID: 22342345 DOI: 10.1016/j.cbpc.2012.01.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 01/18/2012] [Accepted: 01/31/2012] [Indexed: 10/14/2022]
Abstract
This study investigated phosphatidylinositol-3-OH-kinase (PI3-kinase) involvement in the induction of cadmium-mediated oxidative effects on hemocytes of mussel Mytilus galloprovincialis. PI3-kinase was investigated with the use of wortmannin, a specific covalent inhibitor of PI3-kinase. Moreover, phorbol-myristate acetate (PMA), a well-known protein kinase C (PKC)-mediated NADPH oxidase and nitric oxide (NO) synthase stimulator, was also used for elucidating PI3-kinase involvement during the respiratory burst process in challenge hemocytes. According to the results, cells pre-treated with non-toxic concentrations of wortmannin (1 and/or 50 nM, as revealed by neutral red retention assay) for 15 min, showed a significant attenuation of cadmium ability (at concentration of 50 μM) to promote cell death, superoxide anion (O(2)(-)) production, NO generation and lipid peroxidation (in terms of malondialdehyde equivalents). On the other hand, wortmannin-treated cells showed a significant attenuation of PMA ability to induce NO generation but not O(2)(-) production. These findings reveal that PI3-kinase could lead to a PKC-independent induction of NO synthase activity in cells faced with pro-oxidants, such as cadmium, while its activation could be fundamental for the regulation of NAPDH oxidase activity, probably through a PKC-dependent signaling pathway.
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Affiliation(s)
- Christos Vouras
- Department of Biology, Section of Animal Biology, University of Patras, 26500, Greece
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Yoshino TP, Wu XJ, Liu H, Gonzalez LA, Deelder AM, Hokke CH. Glycotope sharing between snail hemolymph and larval schistosomes: larval transformation products alter shared glycan patterns of plasma proteins. PLoS Negl Trop Dis 2012; 6:e1569. [PMID: 22448293 PMCID: PMC3308936 DOI: 10.1371/journal.pntd.0001569] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2011] [Accepted: 02/04/2012] [Indexed: 12/19/2022] Open
Abstract
Recent evidence supports the involvement of inducible, highly diverse lectin-like recognition molecules in snail hemocyte-mediated responses to larval Schistosoma mansoni. Because host lectins likely are involved in initial parasite recognition, we sought to identify specific carbohydrate structures (glycans) shared between larval S. mansoni and its host Biomphalaria glabrata to address possible mechanisms of immune avoidance through mimicry of elements associated with the host immunoreactivity. A panel of monoclonal antibodies (mABs) to specific S. mansoni glycans was used to identify the distribution and abundance of shared glycan epitopes (glycotopes) on plasma glycoproteins from B. glabrata strains that differ in their susceptibilities to infection by S. mansoni. In addition, a major aim of this study was to determine if larval transformation products (LTPs) could bind to plasma proteins, and thereby alter the glycotopes exposed on plasma proteins in a snail strain-specific fashion. Plasma fractions (< 100 kDa/> 100 kDa) from susceptible (NMRI) and resistant (BS-90) snail strains were subjected to SDS-PAGE and immunoblot analyses using mAB to LacdiNAc (LDN), fucosylated LDN variants, Lewis X and trimannosyl core glycans. Results confirmed a high degree of glycan sharing, with NMRI plasma exhibiting a greater distribution/abundance of LDN, F-LDN and F-LDN-F than BS-90 plasma (< 100 kDa fraction). Pretreatment of blotted proteins with LTPs significantly altered the reactivity of specific mABs to shared glycotopes on blots, mainly through the binding of LTPs to plasma proteins resulting in either glycotope blocking or increased glycotope attachment to plasma. Many LTP-mediated changes in shared glycans were snail-strain specific, especially those in the < 100 kDa fraction for NMRI plasma proteins, and for BS-90, mainly those in the > 100 kDa fraction. Our data suggest that differential binding of S. mansoni LTPs to plasma proteins of susceptible and resistant B. glabrata strains may significantly impact early anti-larval immune reactivity, and in turn, compatibility, in this parasite-host system.
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Affiliation(s)
- Timothy P Yoshino
- Department of Pathobiological Sciences, University of Wisconsin School of Veterinary Medicine, Madison, Wisconsin, USA.
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Wang H, Zhao QP, Nie P, Jiang MS, Song J. Identification of differentially expressed genes in Oncomelania hupensis chronically infected with Schistosoma japonicum. Exp Parasitol 2012; 130:374-83. [PMID: 22343044 DOI: 10.1016/j.exppara.2012.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 01/27/2012] [Accepted: 02/02/2012] [Indexed: 11/17/2022]
Abstract
Oncomelania hupensis is the unique intermediate host of Schistosoma japonicum. The schistosome-snail interaction is biomedically important. To identify differentially expressed transcripts in O. hupensis chronically infected with S. japonicum, suppression subtractive hybridization (SSH) was used to construct a cDNA library in each direction for transcripts that are more abundantly enriched in head-foot part of the infected O. hupensis and for those that are more abundantly enriched in the uninfected, as head-foot part contains hemocytes and hemolymph which are associated with the snail internal defense system. After differential screening, 39 transcripts were identified, including nine and 30 transcripts enriched in infected and uninfected snails, respectively. Some of the transcripts have similar homology to available sequences in current databases, including transposase, caveolin-like protein, pancreatic trypsin inhibitor-like protein, prosaposin, glutathione s-transferase (GST), and several hypothetical proteins, while most of the transcripts do not match with any sequences in available databases. The identified transcripts were involved functionally in cell growth, metabolism, signal transduction, and immune responses. Two forward library transcripts and 11 reverse library transcripts were selected for real-time PCR, and 10 of them were confirmed to be consistent with the SSH results. It is intriguing to continue functional studies for some genes such as pancreatic trypsin inhibitor; a hypothetical protein (HS576367) related to calcium ion binding; GST; and several unknown proteins (HS576353 and HS576355). These identified differentially expressed genes may be key targets for understanding the molecular mechanism of co-existence during which the snail is unable to rid itself of the schistosome in chronic infection stage.
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Affiliation(s)
- Hao Wang
- School of Basic Medical Science, Wuhan University, Wuhan, Hubei Province 430071, China
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Wright B, Lacchini AH, Davies AJ, Walker AJ. Regulation of nitric oxide production in snail (Lymnaea stagnalis) defence cells: a role for PKC and ERK signalling pathways. Biol Cell 2012; 98:265-78. [PMID: 16293103 DOI: 10.1042/bc20050066] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND INFORMATION Nitric oxide (NO) is an important molecule in innate immune responses. In molluscs NO is produced by mobile defence cells called haemocytes; however, the molecular mechanisms that regulate NO production in these cells is poorly understood. The present study focused on the role of cell signalling pathways in NO production by primary haemocytes from the snail Lymnaea stagnalis. RESULTS When haemocytes were challenged with PMA (10 microM) or the beta-1,3-glucan laminarin (10 mg/ml), an 8-fold and 4-fold increase in NO production were observed after 60 min respectively. Moreover, the NOS (NO synthase) inhibitors L-NAME (N(G)-nitro-L-arginine methyl ester) and L-NMMA (N(G)-monomethyl-L-arginine) were found to block laminarin- and PMA-induced NO synthesis. Treatment of haemocytes with PMA or laminarin also increased the phosphorylation (activation) status of PKC (protein kinase C). When haemocytes were preincubated with PKC inhibitors (calphostin C or GF109203X) or inhibitors of the ERK (extracellular-signal-regulated kinase) pathway (PD98059 or U0126) prior to challenge, significant reductions in PKC and ERK phosphorylation and NO production were observed following exposure to laminarin or PMA. The greatest effect on NO production was seen with GF109203X and U0126, with PMA-induced NO production inhibited by 94% and 87% and laminarin-induced NO production by 50% and 91% respectively. CONCLUSIONS These data suggest that ERK and PKC comprise part of the signalling machinery that regulates NOS activation and subsequent production of NO in molluscan haemocytes. To our knowledge, this is the first report that shows a role for these signalling proteins in the generation of NO in invertebrate defence cells.
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Affiliation(s)
- Bernice Wright
- School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, UK
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Zahoor Z, Davies AJ, Kirk RS, Rollinson D, Walker AJ. Larval excretory-secretory products from the parasite Schistosoma mansoni modulate HSP70 protein expression in defence cells of its snail host, Biomphalaria glabrata. Cell Stress Chaperones 2010; 15:639-50. [PMID: 20182834 PMCID: PMC3006636 DOI: 10.1007/s12192-010-0176-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 01/27/2010] [Accepted: 01/29/2010] [Indexed: 11/26/2022] Open
Abstract
Synthesis of heat shock proteins (HSPs) following cellular stress is a response shared by many organisms. Amongst the HSP family, the approximately 70 kDa HSPs are the most evolutionarily conserved with intracellular chaperone and extracellular immunoregulatory functions. This study focused on the effects of larval excretory-secretory products (ESPs) from the parasite Schistosoma mansoni on HSP70 protein expression levels in haemocytes (defence cells) from its snail intermediate host Biomphalaria glabrata. S. mansoni larval stage ESPs are known to interfere with haemocyte physiology and behaviour. Haemocytes from two different B. glabrata strains, one which is susceptible to S. mansoni infection and one which is resistant, both showed reduced HSP70 protein levels following 1 h challenge with S. mansoni ESPs when compared to unchallenged controls; however, the reduction observed in the resistant strain was less marked. The decline in intracellular HSP70 protein persisted for at least 5 h in resistant snail haemocytes only. Furthermore, in schistosome-susceptible snails infected by S. mansoni for 35 days, haemocytes possessed approximately 70% less HSP70. The proteasome inhibitor, MG132, partially restored HSP70 protein levels in ESP-challenged haemocytes, demonstrating that the decrease in HSP70 was in part due to intracellular degradation. The extracellular signal-regulated kinase (ERK) signalling pathway appears to regulate HSP70 protein expression in these cells, as the mitogen-activated protein-ERK kinase 1/2 (MEK1/2) inhibitor, U0126, significantly reduced HSP70 protein levels. Disruption of intracellular HSP70 protein expression in B. glabrata haemocytes by S. mansoni ESPs may be a strategy employed by the parasite to manipulate the immune response of the intermediate snail host.
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Affiliation(s)
- Zahida Zahoor
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE UK
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, The Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | - Angela J. Davies
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE UK
| | - Ruth S. Kirk
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE UK
| | - David Rollinson
- Wolfson Wellcome Biomedical Laboratories, Department of Zoology, The Natural History Museum, Cromwell Road, London, SW7 5BD UK
| | - Anthony John Walker
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE UK
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Walker AJ, Lacchini AH, Sealey KL, Mackintosh D, Davies AJ. Spreading by snail (Lymnaea stagnalis) defence cells is regulated through integrated PKC, FAK and Src signalling. Cell Tissue Res 2010; 341:131-45. [PMID: 20512591 DOI: 10.1007/s00441-010-0986-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Accepted: 04/21/2010] [Indexed: 12/25/2022]
Abstract
Cell adhesion and spreading are vital to immune function. In molluscs, haemocytes (circulating phagocytes) are sentinels and effectors of the internal defence system; however, molecular mechanisms that regulate integrin-mediated spreading by haemocytes have not been characterised in detail. Visualisation of Lymnaea stagnalis haemocytes by scanning electron microscopy revealed membrane ruffling, formation of lamellipodia and extensive filopodia during early stages of cell adhesion and spreading. These events correlated with increased phosphorylation (activation) of protein kinase C (PKC) and focal adhesion kinase (FAK), sustained for 60 min. Treatment of haemocytes with the PKC inhibitors GF109203X or Gö 6976, or the Src/tyrosine kinase inhibitors SrcI or herbimycin A, attenuated haemocyte spread by 64, 46, 32 and 35%, respectively (P <or= 0.001); PKC or Src inhibition also prevented focal adhesion formation. Western blotting demonstrated that during spreading and adhesion these inhibitors also impaired PKC and FAK activation, with Gö 6976 or SrcI inhibiting FAK phosphorylation by at least 70% (P <or= 0.001), and herbimycin A or SrcI inhibiting PKC phosphorylation by at least 46% (P <or= 0.01). Confocal microscopy revealed phosphorylated PKC colocalised with focal adhesion sites, particularly during early phases of adhesion and spreading. Finally, fibronectin promoted PKC and FAK phosphorylation in suspended haemocytes demonstrating that activation can occur independent of cell adhesion. These novel data are consistent with PKC and FAK/Src playing an integrated role in integrin activation and integrin-mediated spreading by L. stagnalis haemocytes. We propose a model in which integrin engagement mediates association of PKC with FAK/Src complexes to promote focal adhesion assembly during immune recognition by these cells.
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Affiliation(s)
- Anthony J Walker
- School of Life Sciences, Kingston University, Kingston upon Thames, Surrey, UK.
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Gonzalez-Riopedre M, Barcia R, Ramos-Martínez JI. Implication of PKC isozymes in the release of biogenic amines by mussel hemocytes: effect of PDGF, IL-2, and LPS. ACTA ACUST UNITED AC 2009; 311:727-34. [PMID: 19722220 DOI: 10.1002/jez.566] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The innate immune system of marine mussels (Mytilus galloprovincialis) is operated by phagocytic cells termed hemocytes. Lipopolysaccharide (LPS), interleukin-2 (IL-2), or platelet-derived growth factor (PDGF) increase biogenic amine synthesis in these cells, and the enzymes Ca(2+)-independent protein kinase C (PKC) (p105/108) and Ca(2+)-dependent PKC (p60) are involved in these processes. Stimulation by PDGF induces a down-regulation process affecting the form p108 of the Ca(2+)-independent PKC. In addition, PDGF produces the increase of expression of p60 in the membrane fraction. IL-2 induces the disappearance of p108 from the membrane but does not affect the presence of p60 in cytosol or membrane. For its part, LPS activates exclusively p60 by a down-regulation mechanism. The ensemble of results suggests that each agonist starts a pathway that implicates the PKC isoenzymes that mediate the regulation of the activities dopa decarboxylase, dopamine beta-hydroxilase, and phenyletanolamine N-methyltranferase, which lead to different actions related to biogenic amine synthesis.
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Affiliation(s)
- M Gonzalez-Riopedre
- Department of Biochemistry and Molecular Biology, University of Santiago de Compostela, Campus of Lugo School of Veterinary, 27002 Lugo, Spain
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Protein kinase C signalling during miracidium to mother sporocyst development in the helminth parasite, Schistosoma mansoni. Int J Parasitol 2009; 39:1223-33. [DOI: 10.1016/j.ijpara.2009.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 03/31/2009] [Accepted: 04/02/2009] [Indexed: 12/27/2022]
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The Ca2+-independent PKC (p105) mediates the PMA-activation of marine mussel hemocytes and the Ca2+-dependent PKC (p60) does not intervene. Mol Cell Biochem 2009; 332:243-9. [PMID: 19582549 DOI: 10.1007/s11010-009-0197-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 06/25/2009] [Indexed: 10/20/2022]
Abstract
Previous works revealed the presence of a Ca(2+)-dependent protein kinase (p60) and a Ca(2+)-independent protein kinase (p105) in the mantle tissue from the sea mussel Mytilus galloprovincialis Lmk. The expression of both isoforms shows a balance between cytosolic and membrane fractions in mantle, gills, and hepatopancreas, whereas, in hemocytes, their expression is mainly cytosolic, as happens in muscle tissues with p60 alone. Both enzymatic forms contain phosphorylated serines, and no phosphorylation was detected in tyrosines. Only the form p105 mediates the PMA-induced activation of the hemocytes of M. galloprovincialis, and it does so by a process of down-regulation. The form p60 does not respond to the presence of the phorbol ester, suggesting structural differences related to the binding sites of the diacylglycerol.
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Peterson NA, Hokke CH, Deelder AM, Yoshino TP. Glycotope analysis in miracidia and primary sporocysts of Schistosoma mansoni: differential expression during the miracidium-to-sporocyst transformation. Int J Parasitol 2009; 39:1331-44. [PMID: 19545571 DOI: 10.1016/j.ijpara.2009.06.002] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 06/08/2009] [Accepted: 06/09/2009] [Indexed: 01/25/2023]
Abstract
Fucosylated carbohydrate epitopes (glycotopes) expressed by larval and adult schistosomes are thought to modulate the host immune response and possibly mediate parasite evasion in intermediate and definitive hosts. While previous studies showed glycotope expression is developmentally and stage-specifically regulated, relatively little is known regarding their occurrence in miracidia and primary sporocysts. In this study, previously defined monoclonal antibodies were used in confocal laser scanning microscopy, standard epifluorescence microscopy and Western blot analyses to investigate the developmental expression of the following glycotopes in miracidia and primary sporocysts of Schistosoma mansoni: GalNAcbeta1-4GlcNAc (LDN), GalNAcbeta1-4(Fucalpha1-3)GlcNAc (LDN-F), Fucalpha1-3GalNAcbeta1-4GlcNAc (F-LDN), Fucalpha1-3GalNAcbeta1-4(Fucalpha1-3)GlcNAc (F-LDN-F), GalNAcbeta1-4(Fucalpha1-2Fucalpha1-3)GlcNAc (LDN-DF), Fucalpha1-2Fucalpha1-3GalNAcbeta1-4(Fucalpha1-2Fucalpha1-3)GlcNAc (DF-LDN-DF), Galbeta1-4(Fucalpha1-3)GlcNAc (Lewis X) and the truncated trimannosyl N-glycan Manalpha1-3(Manalpha1-6)Manbeta1-4GlcNAcbeta1-4GlcNAcbeta1-Asn (TriMan). All but Lewis X were variously expressed by miracidia and sporocysts of S. mansoni. Most notably, alpha3-fucosylated LDN (F-LDN, F-LDN-F, LDN-F) was prominently expressed on the larval surface and amongst glycoproteins released during larval transformation and early sporocyst development, possibly implying a role for these glycotopes in snail-schistosome interactions. Interestingly, Fucalpha2Fucalpha3-subsituted LDN (LDN-DF, DF-LDN-DF) and LDN-F were heterogeneously surface-expressed on individuals of a given larval population, particularly amongst miracidia. In contrast, LDN and TriMan primarily localised in internal somatic tissues and exhibited only minor surface expression. Immunoblots indicate that glycotopes occur on overlapping but distinct protein sets in both larval stages, further demonstrating the underlying complexity of schistosome glycosylation. Additionally, sharing of specific larval glycotopes with Biomphalaria glabrata suggests an evolutionary convergence of carbohydrate expression between schistosomes and their snail host.
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Affiliation(s)
- Nathan A Peterson
- Department of Pathobiological Sciences, University of Wisconsin - Madison, School of Veterinary Medicine, 2115 Observatory Drive, Madison, WI 53706, USA
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Bayne CJ. Successful parasitism of vector snail Biomphalaria glabrata by the human blood fluke (trematode) Schistosoma mansoni: a 2009 assessment. Mol Biochem Parasitol 2009; 165:8-18. [PMID: 19393158 PMCID: PMC2765215 DOI: 10.1016/j.molbiopara.2009.01.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 01/08/2009] [Accepted: 01/13/2009] [Indexed: 01/13/2023]
Abstract
Schistosomiasis, caused by infections by human blood flukes (Trematoda), continues to disrupt the lives of over 200,000,000 people in over 70 countries, inflicting misery and precluding the individuals' otherwise reasonable expectations of productive lives. Infection requires contact with freshwater in which infected snails (the intermediate hosts of schistosomes) have released cercariae larvae. Habitats suitable for the host snails continue to expand as a consequence of water resource development. No vaccine is available, and resistance has emerged towards the single licensed schistosomicide drug. Since human infections would cease if parasite infections in snails were prevented, efforts are being made to discover requirements of intra-molluscan development of these parasites. Wherever blood flukes occur, naturally resistant conspecific snails are present. To understand the mechanisms used by parasites to ensure their survival in immunocompetent hosts, one must comprehend the interior defense mechanisms that are available to the host. For one intermediate host snail (Biomphalaria glabrata) and trematodes for which it serves as vector, molecular genetic and proteomic surveys for genes and proteins influencing the outcomes on infections are yielding lists of candidates. A comparative approach drawing on data from studies in divergent species provides a robust basis for hypothesis generation to drive decisions as to which candidates merit detailed further investigation. For example, reactive oxygen and nitrogen species are known mediators or effectors in battles between infectious agents and their hosts. An approach targeting genes involved in relevant pathways has been fruitful in the Schistosoma mansoni -- B. glabrata parasitism, leading to discovery of a functionally relevant gene set (encoding enzymes responsible for the leukocyte respiratory burst) that associates significantly with host resistance phenotype. This review summarizes advances in the understanding of strategies used by both this trematode parasite and its molluscan host to ensure their survival.
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Zahoor Z, Davies AJ, Kirk RS, Rollinson D, Walker AJ. Nitric oxide production by Biomphalaria glabrata haemocytes: effects of Schistosoma mansoni ESPs and regulation through the extracellular signal-regulated kinase pathway. Parasit Vectors 2009; 2:18. [PMID: 19386102 PMCID: PMC2680853 DOI: 10.1186/1756-3305-2-18] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Accepted: 04/22/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Schistosoma mansoni uses Biomphalaria glabrata as an intermediate host during its complex life cycle. In the snail, the parasite initially transforms from a miracidium into a mother sporocyst and during this process excretory-secretory products (ESPs) are released. Nitric oxide (NO) and its reactive intermediates play an important role in host defence responses against pathogens. This study therefore aimed to determine the effects of S. mansoni ESPs on NO production in defence cells (haemocytes) from schistosome-susceptible and schistosome-resistant B. glabrata strains. As S. mansoni ESPs have previously been shown to inhibit extracellular signal-regulated kinase (ERK) phosphorylation (activation) in haemocytes from susceptible, but not resistant, B. glabrata the regulation of NO output by ERK in these cells was also investigated. RESULTS Haemocytes from resistant snails challenged with S. mansoni ESPs (20 mug/ml) over 5 h displayed an increase in NO production that was 3.3 times greater than that observed for unchallenged haemocytes; lower concentrations of ESPs (0.1-10 mug/ml) did not significantly increase NO output. In contrast, haemocytes from susceptible snails showed no significant change in NO output following challenge with ESPs at any concentration used (0.1-20 mug/ml). Western blotting revealed that U0126 (1 muM or 10 muM) blocked the phosphorylation (activation) status of ERK in haemocytes from both snail strains. Inhibition of ERK signalling by U0126 attenuated considerably intracellular NO production in haemocytes from both susceptible and resistant B. glabrata strains, identifying ERK as a key regulator of NO output in these cells. CONCLUSION S. mansoni ESPs differentially influence intracellular NO levels in susceptible and resistant B. glabrata haemocytes, possibly through modulation of the ERK signalling pathway. Such effects might facilitate survival of S. mansoni in its intermediate host.
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Affiliation(s)
- Zahida Zahoor
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK.
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Abstract
SUMMARYInfection with parasitic helminths takes a heavy toll on the health and well-being of humans and their domestic livestock, concomitantly resulting in major economic losses. Analyses have consistently revealed bioactive molecules in extracts of helminths or in their excretory/secretory products that modulate the immune response of the host. It is our view that parasitic helminths are an untapped source of immunomodulatory substances that, in pure form, could become new drugs (or models for drug design) to treat disease. Here, we illustrate the range of immunomodulatory molecules in selected parasitic trematodes, cestodes and nematodes, their impact on the immune cells in the host and how the host may recognize these molecules. There are many examples of the partial characterization of helminth-derived immunomodulatory molecules, but these have not yet translated into new drugs, reflecting the difficulty of isolating and fully characterizing proteins, glycoproteins and lipid-based molecules from small amounts of parasite material. However, this should not deter the investigator, since analytical techniques are now being used to accrue considerable structural information on parasite-derived molecules, even when only minute quantities of tissue are available. With the introduction of methodologies to purify and structurally-characterize molecules from small amounts of tissue and the application of high throughput immunological assays, one would predict that an assessment of parasitic helminths will yield a variety of novel drug candidates in the coming years.
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Zahoor Z, Davies AJ, Kirk RS, Rollinson D, Walker AJ. Disruption of ERK signalling in Biomphalaria glabrata defence cells by Schistosoma mansoni: implications for parasite survival in the snail host. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2008; 32:1561-1571. [PMID: 18619674 DOI: 10.1016/j.dci.2008.05.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 05/20/2008] [Accepted: 05/20/2008] [Indexed: 05/26/2023]
Abstract
Biomphalaria glabrata is an intermediate snail host for the human blood fluke Schistosoma mansoni. To survive in B. glabrata, S. mansoni must suppress the snail's haemocyte-mediated defence response; the molecular mechanisms by which this is achieved remain largely unknown. We report here that S. mansoni excretory-secretory products (ESPs) attenuate phosphorylation of extracellular signal-regulated kinase (ERK) in haemocytes from a B. glabrata strain susceptible to S. mansoni. Whole S. mansoni sporocysts also impair ERK signalling in these cells. In striking contrast, ERK signalling in haemocytes from a B. glabrata strain refractory to schistosome infection is unaffected by ESPs or sporocysts. Effects of ESPs on ERK are similar in the presence or absence of snail plasma, thus ESPs seem to affect haemocytes directly. These findings reveal novel schistosome interference mechanisms; as ERK regulates various haemocyte defence reactions, we propose that disruption of ERK signalling in haemocytes facilitates S. mansoni survival within susceptible B. glabrata.
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Affiliation(s)
- Zahida Zahoor
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston upon Thames, Surrey, KT1 2EE, UK
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Specific tyrosine phosphorylation induced in Schistosoma mansoni miracidia by haemolymph from schistosome susceptible, but not resistant, Biomphalaria glabrata. Parasitology 2007; 135:337-45. [DOI: 10.1017/s0031182007003964] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
SUMMARYMolecular interplay during snail-schistosome interactions is poorly understood and there is much to discover concerning the effect of snail host molecules on molecular processes in schistosomes. Using the Biomphalaria glabrata – Schistosoma mansoni host-parasite system, the effects of exposure to haemolymph, derived from schistosome-resistant and susceptible snail strains, on protein tyrosine phosphorylation in miracidia have been investigated. Western blotting revealed several tyrosine phosphorylated proteins in this larval stage. Exposure of miracidia to haemolymph from susceptible snails for 60 min resulted in a striking, 5-fold, increase in the tyrosine phosphorylation of a 56 kDa (p56) S. mansoni protein. In contrast, haemolymph from resistant snails had little effect on protein tyrosine phosphorylation levels in miracidia. Confocal microscopy revealed that tyrosine phosphorylation was predominantly associated with proteins present in the tegument. Finally, treatment of miracidia with the tyrosine kinase inhibitor genistein significantly impaired their development into primary sporocysts. The results open avenues for research that focus on the potential importance of phospho-p56 to the outcome of schistosome infection in snails, and the significance of protein tyrosine kinase-mediated signalling events to the transformation of S. mansoni larvae.
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García-García E, Prado-Alvarez M, Novoa B, Figueras A, Rosales C. Immune responses of mussel hemocyte subpopulations are differentially regulated by enzymes of the PI 3-K, PKC, and ERK kinase families. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2007; 32:637-653. [PMID: 18045688 DOI: 10.1016/j.dci.2007.10.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2007] [Revised: 10/04/2007] [Accepted: 10/06/2007] [Indexed: 05/25/2023]
Abstract
Various hemocyte cell types have been described in invertebrates, but for most species a functional characterization of different hemocyte cell types is still lacking. In order to characterize some immunological properties of mussel (Mytilus galloprovincialis) hemocytes, cells were separated by flow cytometry and their capacity for phagocytosis, production of reactive oxygen species (ROS), and production of nitric oxide (NO), was examined. Phosphatidylinositol 3-kinase (PI 3-K), protein kinase C (PKC), and extracellular signal-regulated kinase (ERK) inhibitors were also used to biochemically characterize these cell responses. Four morphologically distinct subpopulations, designated R1-R4, were detected. R1, R2, and R3 cells presented different levels of phagocytosis towards zymosan, latex beads, and two bacteria species. Similarly, R1 to R3, but not R4, cells produced ROS, while all subpopulations produced NO, in response to zymosan. Internalization of all phagocytic targets was blocked by PI 3-K inhibition. In addition, internalization of latex particles, but not of bacteria, was partially blocked by PKC or ERK inhibition. Interestingly, phagocytosis of zymosan was impaired by PKC, or ERK inhibitors, only in R2 cells. Zymosan-induced ROS production was blocked by PI 3-K inhibition, but not by PKC, or ERK inhibition. In addition, zymosan-stimulated NO production was affected by PI 3-K inhibition in R1 and R2, but not in R3 or R4 cells. NO production in all cell types was unaffected by PKC inhibition, but ERK inhibition blocked it in R2 cells. These data reveal the existence of profound functional and biochemical differences in mussel hemocytes and indicate that M. galloprovincialis hemocytes are specialized cells fulfilling specific tasks in the context of host defense.
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Affiliation(s)
- Erick García-García
- Department of Immunology, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City DF-04510, Mexico
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Renwick J, Reeves EP, Wientjes FB, Kavanagh K. Translocation of proteins homologous to human neutrophil p47phox and p67phox to the cell membrane in activated hemocytes of Galleria mellonella. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2007; 31:347-59. [PMID: 16920193 DOI: 10.1016/j.dci.2006.06.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Revised: 06/18/2006] [Accepted: 06/20/2006] [Indexed: 05/11/2023]
Abstract
Activation of the superoxide forming respiratory burst oxidase of human neutrophils, crucial in host defence, requires the cytosolic proteins p47phox and p67phox which translocate to the plasma membrane upon cell stimulation and activate flavocytochrome b558, the redox centre of this enzyme system. We have previously demonstrated the presence of proteins (67 and 47kDa) in hemocytes of the insect Galleria mellonella homologous to proteins of the superoxide-forming NADPH oxidase complex of neutrophils. The work presented here illustrates for the first time translocation of homologous hemocyte proteins, 67 and 47kDa from the cytosol to the plasma membrane upon phorbol 12-myristate 13 acetate (PMA) activation. In hemocytes, gliotoxin (GT), the fungal secondary metabolite significantly suppressed PMA-induced superoxide generation in a concentration dependent manner and reduced translocation to basel nonstimulated levels. Primarily these results correlate translocation of hemocyte 47 and 67kDa proteins with PMA induced oxidase activity. Collectively results presented here, demonstrate further cellular and functional similarities between phagocytes of insects and mammals and further justify the use of insects in place of mammals for modelling the innate immune response to microbial pathogens.
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Affiliation(s)
- Julie Renwick
- Medical Mycology Unit, National Institute for Cellular Biotechnology, Department of Biology, NUI Maynooth, Co. Kildare, Ireland
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Zelck UE, Gege BE, Schmid S. Specific inhibitors of mitogen-activated protein kinase and PI3-K pathways impair immune responses by hemocytes of trematode intermediate host snails. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2007; 31:321-31. [PMID: 16926049 DOI: 10.1016/j.dci.2006.06.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2006] [Revised: 06/20/2006] [Accepted: 06/21/2006] [Indexed: 05/11/2023]
Abstract
To characterize molecular mechanisms regulating snail cellular immune responses, the contributions of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3-K) were examined in hemocytes of the trematode intermediate host snails Biomphalaria glabrata and Lymnaea stagnalis. Simultaneous measurement of phagocytosis/encapsulation and H2O2 production by hemocytes in the presence or absence of specific signal transduction inhibitors was used to assess the role of extracellular-signal regulated kinases 1 and 2 (ERK1/2), p38, JNK and PI3-K. Hemocyte spreading was significantly reduced in a dose-dependent manner by the ERK inhibitor, PD098059, and by wortmannin, a potent PI3-K inhibitor. The JNK inhibitor, SP600125, and the p38 kinase inhibitor, SB203580, had no effect on hemocyte spreading. Sheep red blood cell phagocytosis was significantly impaired by PD098059, SP600125, and SB203580. Hydrogen peroxide production during phagocytosis was severely inhibited by PD098059. Additionally, PD098059, but not the other inhibitors, significantly impaired the cellular encapsulation of trematode larvae and H2O2 production during encapsulation. These results suggest that MAPK and PI3-K signal transduction pathways play a pivotal role in the immune responses of snail hemocytes. PI3-K and ERK appear to strongly regulate cell motility. ERK, JNK and p38 contribute to phagocytosis-mediated signal transduction. ERK also play a major role in oxidative burst activation and the encapsulation of trematode larvae by snail hemocytes.
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Affiliation(s)
- Ulrike E Zelck
- Molecular Parasitology Unit, Institute for Tropical Medicine, Wilhelmstr. 27, D-72074 Tuebingen, Germany.
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Iakovleva NV, Gorbushin AM, Storey KB. Modulation of mitogen-activated protein kinases (MAPK) activity in response to different immune stimuli in haemocytes of the common periwinkle Littorina littorea. FISH & SHELLFISH IMMUNOLOGY 2006; 21:315-24. [PMID: 16533608 DOI: 10.1016/j.fsi.2005.12.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 12/15/2005] [Accepted: 12/19/2005] [Indexed: 05/07/2023]
Abstract
The modulation of mitogen-activated protein kinase (MAPK) activity in haemocytes of the common periwinkle (Littorina littorea) in response to immune challenges by lipopolysaccharide from Echerichia coli (LPS), mannan from baker's yeast Saccharomyces cerevisiae and secretory-excretory products (SEP) of trematodes Himasthla elongata (Echinostomatidae) or after the treatment with phorbol ester (PMA) has been studied by Western blotting using affinity purified rabbit polyclonal antibodies. Exposure of the cells in suspension to PMA, LPS and mannan triggered an activation of p38 and ERK2. The JNK-mediated cascade was modulated differently by the elicitors examined. PMA treatment caused a transient activation of the JNK54 isoform, LPS exposure resulted in a decrease in activity of JNK46, and mannan had no effect on JNK phosphorylation status. Incubation of periwinkle haemocytes in culture medium containing trematode SEP did not affect the activity of any MAPK.
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Affiliation(s)
- Nadya V Iakovleva
- Laboratory 13, Institute of Evolutionary Physiology and Biochemistry RAS, 194223, pr. Torez 44, Saint-Petersburg, Russia.
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Walker AJ. Do trematode parasites disrupt defence-cell signalling in their snail hosts? Trends Parasitol 2006; 22:154-9. [PMID: 16488192 DOI: 10.1016/j.pt.2006.02.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2005] [Revised: 01/05/2006] [Accepted: 02/06/2006] [Indexed: 11/19/2022]
Abstract
More than a decade ago, it was postulated that components derived from trematode parasites block receptors on the defence cells of their snail intermediate hosts, thus preventing host-cell activation and parasite elimination. This phenomenon has still not been investigated extensively. However, recent work concerning the molecular regulation of the molluscan defence response provides a new framework for studies that focus on an extension of this original concept - subversion of host cell signalling by trematode parasites. The hypothesis is that, to facilitate survival and replication in their intermediate hosts, trematode parasites down regulate host defence responses by interfering with key signal-transduction pathways in snail defence cells.
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Affiliation(s)
- Anthony J Walker
- School of Life Sciences, Kingston University, Penrhyn Road, Kingston-upon-Thames, Surrey, UK, KT1 2EE.
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Hammerschmidt K, Kurtz J. Surface carbohydrate composition of a tapeworm in its consecutive intermediate hosts: Individual variation and fitness consequences. Int J Parasitol 2005; 35:1499-507. [PMID: 16198355 DOI: 10.1016/j.ijpara.2005.08.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 08/09/2005] [Accepted: 08/09/2005] [Indexed: 11/21/2022]
Abstract
Carbohydrates on parasite surfaces have been shown to play an important role in host-parasite coevolution, mediating host non-self recognition and parasite camouflage. Parasites that switch hosts can change their surface molecules to remain undetected by the diverse immune systems of their different hosts. However, the question of individual variation in surface sugar composition and its relation to infectivity, virulence, immune evasion and growth of a parasite in its different hosts is as yet largely unexplored. We studied such fitness consequences of variation in surface sugars in a sympatric host-parasite system consisting of the cestode Schistocephalus solidus and its intermediate hosts, a copepod and the three-spined stickleback. Using lectins to analyse the sugar composition, we show that the tapeworm changes its surface according to the invertebrate or vertebrate host. Importantly, sugar composition seems to be genetically variable, as shown by differences among tapeworm sibships. These differences are related to variation in parasite fitness in its second intermediate host, i.e. infectivity and growth. Surface sugar composition may thus be a proximate correlate of the evolutionarily relevant variability in infectivity and virulence of parasites in different hosts.
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Affiliation(s)
- Katrin Hammerschmidt
- Department of Evolutionary Ecology, Max-Planck-Institute for Limnology, August-Thienemann-Strasse 2, D-24306 Plön, Germany.
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Humphries JE, Yoshino TP. Schistosoma mansoni excretory-secretory products stimulate a p38 signalling pathway in Biomphalaria glabrata embryonic cells. Int J Parasitol 2005; 36:37-46. [PMID: 16194541 DOI: 10.1016/j.ijpara.2005.08.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Revised: 08/10/2005] [Accepted: 08/17/2005] [Indexed: 10/25/2022]
Abstract
Following infection with Schistosoma mansoni larvae, haemocytes of resistant Biomphalaria glabrata snails execute a rapid defence during which they migrate towards and encapsulate the parasites. Such immediate and precise responses are thought to depend on signal transduction cascades though the signalling components involved remain largely unknown. It is proposed that mitogen-activated protein kinases may play a role in B. glabrata immune signalling, in particular p38 mitogen-activated protein kinases, which are known to be associated with stress and inflammatory signalling. Using degenerate PCR followed by Rapid Amplification of cDNA Ends a full-length p38 mitogen-activated protein kinase-like cDNA was cloned from both the B. glabrata embryonic (Bge) cell line (Bge-p38) and haemocytes (Bgh-p38). In addition, B. glabrata p38 mitogen-activated protein kinase activation was examined at the protein level in Western blot analyses using an antibody that specifically recognises activated/diphosphorylated p38 mitogen-activated protein kinase. Results showed that Bge cell p38 mitogen-activated protein kinase was activated/phosphorylated following 30 min incubation with anisomycin, an established p38 mitogen-activated protein kinase activator. Furthermore, p38 mitogen-activated protein kinase was also activated after only 5 min exposure to either the beta-glucan polymer laminarin or S. mansoni larval excretory-secretory products. In a comparative study, activated haemocyte p38 mitogen-activated protein kinase could also be detected using the anti-phosphorylated p38 antibody following cell treatment with anisomycin. However, in contrast with Bge cells, haemocyte p38 was not activated by either excretory-secretory products or laminarin treatments, suggesting fundamental differences in the role of p38 mitogen-activated protein kinase in signal transduction pathways between haemocytes and Bge cells.
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Affiliation(s)
- Judith E Humphries
- Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI 53706, USA.
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Abstract
There is a growing understanding of risks posed by human contact with the cercariae of bird schistosomes. In general, there are no fundamental biological differences between human and bird schistosomes in terms of their interactions with snail and vertebrate hosts. The penetration of host surfaces is accompanied by the release of penetration gland products and the shedding of highly antigenic surface components (miracidial ciliated plates and cercarial glycocalyx) which trigger host immune reactions. New surface structures are formed during transformation: the tegument of mother sporocysts and the tegumental double membrane of schistosomula. These surfaces apparently serve as protection against the host immune response. Certain parasite excretory-secretory products may contribute to immunosuppression or, on the other hand, stimulation of host immune reactions. Discovery of new species and their life cycles, the characterization of host-parasite interactions (including at the molecular level), the determination of parasite pathogenicity towards the host, the development of tools for differential diagnosis and the application of protective measures are all topical research streams of the future. Regularly updated information on bird schistosomes and cercarial dermatitis can be found at http://www.schistosomes.cz (web pages of Schistosome Group Prague).
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Affiliation(s)
- P Horák
- Department of Parasitology, Faculty of Science, Charles University, Vinicná 7, CZ-12844 Prague 2, Czech Republic.
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