1
|
Hagen J, Sarkies P, Selkirk ME. Lentiviral transduction facilitates RNA interference in the nematode parasite Nippostrongylus brasiliensis. PLoS Pathog 2021; 17:e1009286. [PMID: 33497411 PMCID: PMC7864396 DOI: 10.1371/journal.ppat.1009286] [Citation(s) in RCA: 7] [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: 10/17/2020] [Revised: 02/05/2021] [Accepted: 01/06/2021] [Indexed: 12/16/2022] Open
Abstract
Animal-parasitic nematodes have thus far been largely refractory to genetic manipulation, and methods employed to effect RNA interference (RNAi) have been ineffective or inconsistent in most cases. We describe here a new approach for genetic manipulation of Nippostrongylus brasiliensis, a widely used laboratory model of gastrointestinal nematode infection. N. brasiliensis was successfully transduced with Vesicular Stomatitis Virus glycoprotein G (VSV-G)-pseudotyped lentivirus. The virus was taken up via the nematode intestine, RNA reverse transcribed into proviral DNA, and transgene transcripts produced stably in infective larvae, which resulted in expression of the reporter protein mCherry. Improved transgene expression was achieved by incorporating the C. elegans hlh11 promoter and the tbb2 3´-UTR into viral constructs. MicroRNA-adapted short hairpin RNAs delivered in this manner were processed correctly and resulted in partial knockdown of β-tubulin isotype-1 (tbb-iso-1) and secreted acetylcholinesterase B (ache-B). The system was further refined by lentiviral delivery of double stranded RNAs, which acted as a trigger for RNAi following processing and generation of 22G-RNAs. Virus-encoded sequences were detectable in F1 eggs and third stage larvae, demonstrating that proviral DNA entered the germline and was heritable. Lentiviral transduction thus provides a new means for genetic manipulation of parasitic nematodes, including gene silencing and expression of exogenous genes. The complex life cycle of parasitic nematodes makes them very difficult to manipulate genetically, and methods to delete or silence genes which are routinely used in other organisms are ineffective in most species of nematodes which infect animals. This has hindered attempts to understand the function of defined genes and proteins, and their roles in development and interaction of nematode parasites with their host. We show here that foreign genetic material can be introduced into a widely used laboratory model of intestinal nematode infection by using a viral vector. The vector was modified to improve transgene expression, and a reporter protein expressed by transduced nematode larvae in vitro. We subsequently utilised the viral vector to deliver double stranded RNA molecules to the larvae. These molecules were processed along known pathways, resulting in partial knockdown of two test genes. This system represents a new means of genetically manipulating nematode parasites, and will aid in understanding their complex biology, in addition to defining new targets for control of infection.
Collapse
Affiliation(s)
- Jana Hagen
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Peter Sarkies
- MRC London Institute of Medical Sciences, Imperial College London, London, United Kingdom
| | - Murray E. Selkirk
- Department of Life Sciences, Imperial College London, London, United Kingdom
- * E-mail:
| |
Collapse
|
2
|
The multiple biological roles of the cholinesterases. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:41-56. [PMID: 33307019 DOI: 10.1016/j.pbiomolbio.2020.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022]
Abstract
It is tacitly assumed that the biological role of acetylcholinesterase is termination of synaptic transmission at cholinergic synapses. However, together with its structural homolog, butyrylcholinesterase, it is widely distributed both within and outside the nervous system, and, in many cases, the role of both enzymes remains obscure. The transient appearance of the cholinesterases in embryonic tissues is especially enigmatic. The two enzymes' extra-synaptic roles, which are known as 'non-classical' roles, are the topic of this review. Strong evidence has been presented that AChE and BChE play morphogenetic roles in a variety of eukaryotic systems, and they do so either by acting as adhesion proteins, or as trophic factors. As trophic factors, one mode of action is to directly regulate morphogenesis, such as neurite outgrowth, by poorly understood mechanisms. The other mode is by regulating levels of acetylcholine, which acts as the direct trophic factor. Alternate substrates have been sought for the cholinesterases. Quite recently, it was shown that levels of the aggression hormone, ghrelin, which also controls appetite, are regulated by butyrylcholinesterase. The rapid hydrolysis of acetylcholine by acetylcholinesterase generates high local proton concentrations. The possible biophysical and biological consequences of this effect are discussed. The biological significance of the acetylcholinesterases secreted by parasitic nematodes is reviewed, and, finally, the involvement of acetylcholinesterase in apoptosis is considered.
Collapse
|
3
|
Weatherhead JE, Gazzinelli-Guimaraes P, Knight JM, Fujiwara R, Hotez PJ, Bottazzi ME, Corry DB. Host Immunity and Inflammation to Pulmonary Helminth Infections. Front Immunol 2020; 11:594520. [PMID: 33193446 PMCID: PMC7606285 DOI: 10.3389/fimmu.2020.594520] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 09/30/2020] [Indexed: 01/04/2023] Open
Abstract
Helminths, including nematodes, cestodes and trematodes, are complex parasitic organisms that infect at least one billion people globally living in extreme poverty. Helminthic infections are associated with severe morbidity particularly in young children who often harbor the highest burden of disease. While each helminth species completes a distinct life cycle within the host, several helminths incite significant lung disease. This impact on the lungs occurs either directly from larval migration and host immune activation or indirectly from a systemic inflammatory immune response. The impact of helminths on the pulmonary immune response involves a sophisticated orchestration and activation of the host innate and adaptive immune cells. The consequences of activating pulmonary host immune responses are variable with several helminthic infections leading to severe, pulmonary compromise while others providing immune tolerance and protection against the development of pulmonary diseases. Further delineation of the convoluted interface between helminth infection and the pulmonary host immune responses is critical to the development of novel therapeutics that are critically needed to prevent the significant global morbidity caused by these parasites.
Collapse
Affiliation(s)
- Jill E. Weatherhead
- Department of Medicine, Infectious Diseases, Baylor College of Medicine, Houston, TX, United States
- Department of Pediatrics, Pediatric Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | | | - John M. Knight
- Department of Medicine, Pathology and Immunology, and the Biology of Inflammation Center, Baylor College of Medicine, Houston, TX, United States
| | - Ricardo Fujiwara
- Departamento de Parasitologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Peter J. Hotez
- Department of Pediatrics, Pediatric Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Center for Vaccine Development, Houston, TX, United States
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
- Department of Biology, Baylor University, Waco, TX, United States
- Hagler Institute for Advanced Study at Texas A&M University, College State, TX, United States
| | - Maria Elena Bottazzi
- Department of Pediatrics, Pediatric Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
- Texas Children’s Center for Vaccine Development, Houston, TX, United States
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, TX, United States
| | - David B. Corry
- Department of Medicine, Pathology and Immunology, and the Biology of Inflammation Center, Baylor College of Medicine, Houston, TX, United States
- Department of Medicine, Immunology, Allergy, Rheumatology, Baylor College of Medicine, Houston, TX, United States
- Michael E. DeBakey VA Center for Translational Research in Inflammatory Diseases, Houston, TX, United States
| |
Collapse
|
4
|
Characterisation of the secreted apyrase family of Heligmosomoides polygyrus. Int J Parasitol 2020; 51:39-48. [PMID: 32931780 DOI: 10.1016/j.ijpara.2020.07.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 12/21/2022]
Abstract
Apyrases are a recurrent feature of secretomes from numerous species of parasitic nematodes. Here we characterise the five apyrases secreted by Heligmosomoides polygyrus, a natural parasite of mice and a widely used laboratory model for intestinal nematode infection. All five enzymes are closely related to soluble calcium-activated nucleotidases described in a variety of organisms, and distinct from the CD39 family of ecto-nucleotidases. Expression is maximal in adult worms and restricted to adults and L4s. Recombinant apyrases were produced and purified from Pichia pastoris. The five enzymes showed very similar biochemical properties, with strict calcium dependence and a broad substrate specificity, catalysing the hydrolysis of all nucleoside tri- and diphosphates, with no activity against nucleoside monophosphates. Natural infection of mice provoked very low antibodies to any enzyme, but immunisation with an apyrase cocktail showed partial protection against reinfection, with reduced egg output and parasite recovery. The most likely role for nematode secreted apyrases is hydrolysis of extracellular ATP, which acts as an alarmin for cellular release of IL-33 and initiation of type 2 immunity.
Collapse
|
5
|
Tedla BA, Sotillo J, Pickering D, Eichenberger RM, Ryan S, Becker L, Loukas A, Pearson MS. Novel cholinesterase paralogs of Schistosoma mansoni have perceived roles in cholinergic signalling and drug detoxification and are essential for parasite survival. PLoS Pathog 2019; 15:e1008213. [PMID: 31809524 PMCID: PMC6919630 DOI: 10.1371/journal.ppat.1008213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 12/18/2019] [Accepted: 11/13/2019] [Indexed: 01/27/2023] Open
Abstract
Cholinesterase (ChE) function in schistosomes is essential for orchestration of parasite neurotransmission but has been poorly defined with respect to the molecules responsible. Interrogation of the S. mansoni genome has revealed the presence of three ChE domain-containing genes (Smche)s, which we have shown to encode two functional acetylcholinesterases (AChE)s (Smache1 –smp_154600 and Smache2 –smp_136690) and a butyrylcholinesterase (BChE) (Smbche1 –smp_125350). Antibodies to recombinant forms of each SmChE localized the proteins to the tegument of adults and schistosomula and developmental expression profiling differed among the three molecules, suggestive of functions extending beyond traditional cholinergic signaling. For the first time in schistosomes, we identified ChE enzymatic activity in fluke excretory/secretory (ES) products and, using proteomic approaches, attributed this activity to the presence of SmAChE1 and SmBChE1. Parasite survival in vitro and in vivo was significantly impaired by silencing of each smche, either individually or in combination, attesting to the essential roles of these molecules. Lastly, in the first characterization study of a BChE from helminths, evidence is provided that SmBChE1 may act as a bio-scavenger of AChE inhibitors as the addition of recombinant SmBChE1 to parasite cultures mitigated the effect of the anti-schistosome AChE inhibitor 2,2- dichlorovinyl dimethyl phosphate—dichlorvos (DDVP), whereas smbche1-silenced parasites displayed increased sensitivity to DDVP. Cholinesterases—aceytlcholinesterases (AChE)s and butyrylcholinesterases (BChE)s—are multi-functional enzymes that play a pivotal role in the nervous system of parasites by regulating neurotransmission through acetylcholine hydrolysis. Herein, we provide a detailed characterization of schistosome cholinesterases using molecular, enzymatic and gene-silencing approaches and show evidence for these molecules having roles in addition to their neuronal function. Further, we demonstrate the importance of these proteins to parasite development and survival through gene knockdown experiments in laboratory animals, providing evidence for the use of these proteins in the development of novel intervention strategies against schistosomiasis.
Collapse
Affiliation(s)
- Bemnet A. Tedla
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Javier Sotillo
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
- Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - Darren Pickering
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Ramon M. Eichenberger
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
- Institute of Parasitology, University of Zurich, Zurich, Switzerland
| | - Stephanie Ryan
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Luke Becker
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
| | - Mark S. Pearson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland, Australia
- * E-mail:
| |
Collapse
|
6
|
Inclan-Rico JM, Siracusa MC. First Responders: Innate Immunity to Helminths. Trends Parasitol 2018; 34:861-880. [PMID: 30177466 PMCID: PMC6168350 DOI: 10.1016/j.pt.2018.08.007] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/11/2018] [Accepted: 08/12/2018] [Indexed: 02/07/2023]
Abstract
Helminth infections represent a significant public health concern resulting in devastating morbidity and economic consequences across the globe. Helminths migrate through mucosal sites causing tissue damage and the induction of type 2 immune responses. Antihelminth protection relies on the mobilization and activation of multiple immune cells, including type 2 innate lymphocytes (ILC2s), basophils, mast cells, macrophages, and hematopoietic stem/progenitor cells. Further, epithelial cells and neurons have been recognized as important regulators of type 2 immunity. Collectively, these pathways stimulate host-protective responses necessary for worm expulsion and the healing of affected tissues. In this review we focus on the innate immune pathways that regulate immunity to helminth parasites and describe how better understanding of these pathways may lead to the development of new therapeutic strategies.
Collapse
Affiliation(s)
- Juan M Inclan-Rico
- Center for Immunity and Inflammation, Department of Medicine, New Jersey Medical School, Rutgers-The State University of New Jersey, Newark, NJ, USA
| | - Mark C Siracusa
- Center for Immunity and Inflammation, Department of Medicine, New Jersey Medical School, Rutgers-The State University of New Jersey, Newark, NJ, USA.
| |
Collapse
|
7
|
Chatonnet A, Lenfant N, Marchot P, Selkirk ME. Natural genomic amplification of cholinesterase genes in animals. J Neurochem 2017; 142 Suppl 2:73-81. [PMID: 28382676 DOI: 10.1111/jnc.13990] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/07/2017] [Accepted: 02/09/2017] [Indexed: 12/31/2022]
Abstract
Tight control of the concentration of acetylcholine at cholinergic synapses requires precise regulation of the number and state of the acetylcholine receptors, and of the synthesis and degradation of the neurotransmitter. In particular, the cholinesterase activity has to be controlled exquisitely. In the genome of the first experimental models used (man, mouse, zebrafish and drosophila), there are only one or two genes coding for cholinesterases, whereas there are more genes for their closest relatives the carboxylesterases. Natural amplification of cholinesterase genes was first found to occur in some cancer cells and in insect species subjected to evolutionary pressure by insecticides. Analysis of the complete genome sequences of numerous representatives of the various metazoan phyla show that moderate amplification of cholinesterase genes is not uncommon in molluscs, echinoderms, hemichordates, prochordates or lepidosauria. Amplification of acetylcholinesterase genes is also a feature of parasitic nematodes or ticks. In these parasites, over-production of cholinesterase-like proteins in secreted products and the saliva are presumed to have effector roles related to host infection. These amplification events raise questions about the role of the amplified gene products, and the adaptation processes necessary to preserve efficient cholinergic transmission. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms.
Collapse
Affiliation(s)
- Arnaud Chatonnet
- Dynamique Musculaire et Métabolisme, INRA, Université Montpellier, Place Viala, Montpellier France
| | - Nicolas Lenfant
- Dynamique Musculaire et Métabolisme, INRA, Université Montpellier, Place Viala, Montpellier France.,Aix-Marseille Université / Centre National de la Recherche Scientifique, Architecture et Fonction des Macromolécules Biologiques laboratory, Marseille, France
| | - Pascale Marchot
- Aix-Marseille Université / Centre National de la Recherche Scientifique, Architecture et Fonction des Macromolécules Biologiques laboratory, Marseille, France
| | - Murray E Selkirk
- Department of Life Sciences, Imperial College London, London, UK
| |
Collapse
|
8
|
The genome ofStrongyloidesspp. gives insights into protein families with a putative role in nematode parasitism. Parasitology 2016; 144:343-358. [DOI: 10.1017/s0031182016001554] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
SUMMARYParasitic nematodes are important and abundant parasites adapted to live a parasitic lifestyle, with these adaptations all aimed at facilitating their survival and reproduction in their hosts. The recently sequenced genomes of fourStrongyloidesspecies, gastrointestinal parasites of humans and other animals, alongside transcriptomic and proteomic analysis of free-living and parasitic stages of their life cycles have revealed a number of protein families with a putative role in their parasitism. Many of these protein families have also been associated with parasitism in other parasitic nematode species, suggesting that these proteins may play a fundamental role in nematode parasitism more generally. Here, we review key protein families that have a putative role inStrongyloides’ parasitism – acetylcholinesterases, astacins, aspartic proteases, prolyl oligopeptidases, proteinase inhibitors (trypsin inhibitors and cystatins), SCP/TAPS and transthyretin-like proteins – and the evidence for their key, yet diverse, roles in the parasitic lifestyle.
Collapse
|
9
|
Meng X, Li C, Xiu C, Zhang J, Li J, Huang L, Zhang Y, Liu Z. Identification and Biochemical Properties of Two New Acetylcholinesterases in the Pond Wolf Spider (Pardosa pseudoannulata). PLoS One 2016; 11:e0158011. [PMID: 27337188 PMCID: PMC4919072 DOI: 10.1371/journal.pone.0158011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 06/08/2016] [Indexed: 01/17/2023] Open
Abstract
Acetylcholinesterase (AChE), an important neurotransmitter hydrolase in both invertebrates and vertebrates, is targeted by organophosphorus and carbamate insecticides. In this study, two new AChEs were identified in the pond wolf spider Pardosa pseudoannulata, an important predatory natural enemy of several insect pests. In total, four AChEs were found in P. pseudoannulata (including two AChEs previously identified in our laboratory). The new putative AChEs PpAChE3 and PpAChE4 contain most of the common features of the AChE family, including cysteine residues, choline binding sites, the conserved sequence 'FGESAG' and conserved aromatic residues but with a catalytic triad of 'SDH' rather than 'SEH'. Recombinant enzymes expressed in Sf9 cells showed significant differences in biochemical properties compared to other AChEs, such as the optimal pH, substrate specificity, and catalytic efficiency. Among three test substrates, PpAChE1, PpAChE3 and PpAChE4 showed the highest catalytic efficiency (Vmax/KM) for ATC (acetylthiocholine iodide), with PpAChE3 exhibiting a clear preference for ATC based on the VmaxATC/VmaxBTC ratio. In addition, the four PpAChEs were more sensitive to the AChE-specific inhibitor BW284C51, which acts against ATC hydrolysis, than to the BChE-specific inhibitor ISO-OMPA, which acts against BTC hydrolysis, with at least a 8.5-fold difference in IC50 values for each PpAChE. PpAChE3, PpAChE4, and PpAChE1 were more sensitive than PpAChE2 to the tested Carb insecticides, and PpAChE3 was more sensitive than the other three AChEs to the tested OP insecticides. Based on all the results, two new functional AChEs were identified from P. pseudoannulata. The differences in AChE sequence between this spider and insects enrich our knowledge of invertebrate AChE diversity, and our findings will be helpful for understanding the selectivity of insecticides between insects and natural enemy spiders.
Collapse
Affiliation(s)
- Xiangkun Meng
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Chunrui Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Chunli Xiu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Jianhua Zhang
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Jingjing Li
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Lixin Huang
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
| | - Yixi Zhang
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
- * E-mail: (ZWL); (YXZ)
| | - Zewen Liu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing, 210095, China
- * E-mail: (ZWL); (YXZ)
| |
Collapse
|
10
|
Laffy PW, Benkendorff K, Abbott CA. Suppressive subtractive hybridisation transcriptomics provides a novel insight into the functional role of the hypobranchial gland in a marine mollusc. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY D-GENOMICS & PROTEOMICS 2013; 8:111-22. [PMID: 23422501 DOI: 10.1016/j.cbd.2013.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 01/18/2013] [Accepted: 01/18/2013] [Indexed: 11/28/2022]
Abstract
The hypobranchial gland present in gastropods is an organ whose function is not clearly understood. Involved in mucus production, within members of the family Muricidae it is also the source of the ancient dye Tyrian purple and its bioactive precursors. To gain further insights into hypobranchial gland biology, suppressive subtractive hybridisation was performed on hypobranchial gland and mantle tissue from the marine snail Dicathais orbita creating a differentially expressed cDNA library. 437 clones were randomly sequenced, analysed and annotated and 110 sequences had their functions putatively identified. Importantly this approach identified a putative gene involved in Tyrian purple biosynthesis, an arylsulphatase gene. Confirmation of the upregulation of arylsulphatase in the hypobranchial gland compared to the mantle was demonstrated using quantitative real-time PCR. Other genes identified as playing an important role in the hypobranchial gland were those involved in mucus protein synthesis, choline ester regulation, protein and energy production. This study confirms that the hypobranchial gland is involved in the production of mucus secretion and also identifies it as a site of chemical interaction and biosynthesis. This study lays the foundation for a better understanding of the enzymatic production of Tyrian purple precursors within the gland.
Collapse
Affiliation(s)
- Patrick W Laffy
- School of Biological Sciences, Flinders University, GPO Box 2100 Adelaide SA 5001, Australia.
| | | | | |
Collapse
|
11
|
Wolstenholme AJ. Ion channels and receptor as targets for the control of parasitic nematodes. Int J Parasitol Drugs Drug Resist 2011; 1:2-13. [PMID: 24533259 PMCID: PMC3898135 DOI: 10.1016/j.ijpddr.2011.09.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/14/2011] [Accepted: 09/21/2011] [Indexed: 01/19/2023]
Abstract
Many of the anthelmintic drugs in use today act on the nematode nervous system. Ion channel targets have some obvious advantages. They tend to act quickly, which means that they will clear many infections rapidly. They produce very obvious effects on the worms, typically paralyzing them, and these effects are suitable for use in rapid and high-throughput assays. Many of the ion channels and enzymes targeted can also be incorporated into such assays. The macrocyclic lactones bind to an allosteric site on glutamate-gated chloride channels, either directly activating the channel or enhancing the effect of the normal agonist, glutamate. Many old and new anthelmintics, including tribendimidine and the amino-acetonitrile derivatives, act as agonists at nicotinic acetylcholine receptors; derquantel is an antagonist at these receptors. Nematodes express many different types of nicotinic receptor and this diversity means that they are likely to remain important targets for the foreseeable future. Emodepside may have multiple effects, affecting both a potassium channel and a pre-synaptic G protein-coupled receptor; although few other current drugs act at such targets, this example indicates that they may be more important in the future. The nematode nervous system contains many other ion channels and receptors that have not so far been exploited in worm control but which should be explored in the development of effective new compounds.
Collapse
Affiliation(s)
- Adrian J. Wolstenholme
- Dept. of Infectious Diseases and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| |
Collapse
|
12
|
|
13
|
Hewitson JP, Harcus Y, Murray J, van Agtmaal M, Filbey KJ, Grainger JR, Bridgett S, Blaxter ML, Ashton PD, Ashford DA, Curwen RS, Wilson RA, Dowle AA, Maizels RM. Proteomic analysis of secretory products from the model gastrointestinal nematode Heligmosomoides polygyrus reveals dominance of venom allergen-like (VAL) proteins. J Proteomics 2011; 74:1573-94. [PMID: 21722761 DOI: 10.1016/j.jprot.2011.06.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Revised: 05/20/2011] [Accepted: 06/05/2011] [Indexed: 01/25/2023]
Abstract
The intestinal helminth parasite, Heligmosomoides polygyrus bakeri offers a tractable experimental model for human hookworm infections such as Ancylostoma duodenale and veterinary parasites such as Haemonchus contortus. Parasite excretory-secretory (ES) products represent the major focus for immunological and biochemical analyses, and contain immunomodulatory molecules responsible for nematode immune evasion. In a proteomic analysis of adult H. polygyrus secretions (termed HES) matched to an extensive transcriptomic dataset, we identified 374 HES proteins by LC-MS/MS, which were distinct from those in somatic extract HEx, comprising 446 identified proteins, confirming selective export of ES proteins. The predominant secreted protein families were proteases (astacins and other metalloproteases, aspartic, cysteine and serine-type proteases), lysozymes, apyrases and acetylcholinesterases. The most abundant products were members of the highly divergent venom allergen-like (VAL) family, related to Ancylostoma secreted protein (ASP); 25 homologues were identified, with VAL-1 and -2 also shown to be associated with the parasite surface. The dominance of VAL proteins is similar to profiles reported for Ancylostoma and Haemonchus ES products. Overall, this study shows that the secretions of H. polygyrus closely parallel those of clinically important GI nematodes, confirming the value of this parasite as a model of helminth infection.
Collapse
Affiliation(s)
- James P Hewitson
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3JT, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Evolution of cholinesterases in the animal kingdom. Chem Biol Interact 2010; 187:27-33. [DOI: 10.1016/j.cbi.2010.03.043] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2010] [Revised: 03/22/2010] [Accepted: 03/23/2010] [Indexed: 11/21/2022]
|
15
|
Roepcke CBS, Muench SB, Schulze H, Bachmann TT, Schmid RD, Hauer B. Analysis of phosphorothionate pesticides using a chloroperoxidase pretreatment and acetylcholinesterase biosensor detection. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:8748-8756. [PMID: 20614938 DOI: 10.1021/jf1013204] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Acetylcholinesterase (AChE) is responsible for the hydrolysis of acetylcholine in the nervous system. It is inhibited by organophosphate and carbamate pesticides. However, this enzyme is only slightly inhibited by organophosphorothionates, which makes the detection of these pesticides analytically very difficult. A new enzymatic method for the activation and detection of phosphorothionates was developed with the capability to be used directly in food samples without the need of laborious solvent extraction steps. Chloroperoxidase (CPO) from Caldariomyces fumago was combined with tert-butyl hydroperoxide and two halides. Chlorpyrifos and triazophos were completely oxidized. Fenitrothion, methidathion and parathion methyl showed conversion rates between 54 and 61%. Furthermore, the oxidized solution was submitted to an AChE biosensor assay. Chlorpyrifos spiked in organic orange juice was oxidized, where its oxon product was detected in concentrations down to 5 microg/L (final concentration food sample: 25 microg/L). The complete duration of the method takes about 2 h.
Collapse
Affiliation(s)
- Clarisse B S Roepcke
- University of Stuttgart, Institute of Technical Biochemistry, Allmandring 31, 70569 Stuttgart, Germany.
| | | | | | | | | | | |
Collapse
|
16
|
Huang SCC, Chan DTY, Smyth DJ, Ball G, Gounaris K, Selkirk ME. Activation of Nippostrongylus brasiliensis infective larvae is regulated by a pathway distinct from the hookworm Ancylostoma caninum. Int J Parasitol 2010; 40:1619-28. [PMID: 20654619 DOI: 10.1016/j.ijpara.2010.06.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2010] [Revised: 06/11/2010] [Accepted: 06/15/2010] [Indexed: 10/19/2022]
Abstract
Developmentally arrested infective larvae of strongylid nematodes are activated to resume growth by host-derived cues encountered during invasion of the mammalian host. Exposure of Nippostrongylus brasiliensis infective larvae to elevated temperature (37°C) is sufficient to activate signalling pathways which result in resumption of feeding and protein secretion. This occurs independently of exposure to serum or glutathione, in contrast to the hookworm Ancylostoma caninum, and is not initiated by chemical exsheathment. No qualitative differences in protein secretion were induced by host serum as visualised by two-dimensional SDS-PAGE, although exposure of larvae to an aqueous extract of rat skin did stimulate secretion of a small pre-synthesised bolus of proteins. Infective larvae began feeding after a lag period of 3-4 h at 37°C, reaching a maximum of 90% of the population feeding by 48 h. Neither a membrane permeant analogue of cyclic GMP nor muscarinic acetylcholine receptor agonists stimulated feeding at 20°C, and high concentrations of both compounds inhibited temperature-induced activation. LY294002, an inhibitor of phosphatidylinositol 3-kinase, Akt inhibitor IV, an inhibitor of Akt protein kinase, and ketoconazole, an inhibitor of cytochrome P450, all blocked resumption of feeding and protein secretion at 37°C. Serotonin increased the rate of feeding assessed by uptake of radiolabelled BSA, but could not initiate feeding independently of elevated temperature. Collectively, the data suggest that the early signalling events for larval activation in N. brasiliensis differ substantially from A. caninum, but that they may converge at pathways downstream of phosphatidylinositol 3-kinase involving steroid hormone synthesis.
Collapse
Affiliation(s)
- Stanley Ching-Cheng Huang
- Division of Cell & Molecular Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ, UK
| | | | | | | | | | | |
Collapse
|
17
|
Yang Z, Chen J, Chen Y, Jiang S. Molecular cloning and characterization of an acetylcholinesterase cDNA in the brown planthopper, Nilaparvata lugens. JOURNAL OF INSECT SCIENCE (ONLINE) 2010; 10:102. [PMID: 20874389 PMCID: PMC3016860 DOI: 10.1673/031.010.10201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 01/02/2009] [Indexed: 05/29/2023]
Abstract
A full cDNA encoding an acetylcholinesterase (AChE, EC 3.1.1.7) was cloned and characterized from the brown planthopper, Nilaparvata lugens Stål (Hemiptera: Delphacidae). The complete cDNA (2467 bp) contains a 1938-bp open reading frame encoding 646 amino acid residues. The amino acid sequence of the AChE deduced from the cDNA consists of 30 residues for a putative signal peptide and 616 residues for the mature protein with a predicted molecular weight of 69,418. The three residues (Ser242, Glu371, and His485) that putatively form the catalytic triad and the six Cys that form intra-subunit disulfide bonds are completely conserved, and 10 out of the 14 aromatic residues lining the active site gorge of the AChE are also conserved. Northern blot analysis of poly(A)+ RNA showed an approximately 2.6-kb transcript, and Southern blot analysis revealed there likely was just a single copy of this gene in N. lugens. The deduced protein sequence is most similar to AChE of Nephotettix cincticeps with 83% amino acid identity. Phylogenetic analysis constructed with 45 AChEs from 30 species showed that the deduced N. lugens AChE formed a cluster with the other 8 insect AChE2s. Additionally, the hypervariable region and amino acids specific to insect AChE2 also existed in the AChE of N. lugens. The results revealed that the AChE cDNA cloned in this work belongs to insect AChE2 subgroup, which is orthologous to Drosophila AChE. Comparison of the AChEs between the susceptible and resistant strains revealed a point mutation, Gly185Ser, is likely responsible for the insensitivity of the AChE to methamidopho in the resistant strain.
Collapse
Affiliation(s)
- Zhifan Yang
- College of Life Sciences, Hubei University, Wuhan 430062, China.
| | | | | | | |
Collapse
|
18
|
Hewitson JP, Grainger JR, Maizels RM. Helminth immunoregulation: the role of parasite secreted proteins in modulating host immunity. Mol Biochem Parasitol 2009; 167:1-11. [PMID: 19406170 PMCID: PMC2706953 DOI: 10.1016/j.molbiopara.2009.04.008] [Citation(s) in RCA: 529] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/17/2009] [Accepted: 04/21/2009] [Indexed: 11/28/2022]
Abstract
Helminths are masterful immunoregulators. A characteristic feature of helminth infection is a Th2-dominated immune response, but stimulation of immunoregulatory cell populations, such as regulatory T cells and alternatively activated macrophages, is equally common. Typically, Th1/17 immunity is blocked and productive effector responses are muted, allowing survival of the parasite in a "modified Th2" environment. Drug treatment to clear the worms reverses the immunoregulatory effects, indicating that a state of active suppression is maintained by the parasite. Hence, research has focussed on "excretory-secretory" products released by live parasites, which can interfere with every aspect of host immunity from initial recognition to end-stage effector mechanisms. In this review, we survey our knowledge of helminth secreted molecules, and summarise current understanding of the growing number of individual helminth mediators that have been shown to target key receptors or pathways in the mammalian immune system.
Collapse
Affiliation(s)
| | | | - Rick M. Maizels
- Centre for Immunity, Infection and Evolution, Institute of Immunology and Infection Research, University of Edinburgh, West Mains Road, Edinburgh EH9 3JT, UK
| |
Collapse
|
19
|
Old and new questions about cholinesterases. Chem Biol Interact 2008; 175:30-44. [DOI: 10.1016/j.cbi.2008.04.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 04/25/2008] [Accepted: 04/28/2008] [Indexed: 01/21/2023]
|
20
|
Mohamed MA, Abdel-Gawad AS, Ghazy AEM. Purification and characterization of an acetylcholinesterase from the infective juveniles of Heterorhabditis bacteriophora. Comp Biochem Physiol C Toxicol Pharmacol 2007; 146:314-24. [PMID: 17531543 DOI: 10.1016/j.cbpc.2007.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2006] [Revised: 04/04/2007] [Accepted: 04/06/2007] [Indexed: 10/23/2022]
Abstract
Acetylcholinesterases (AChEs) have been estimated in the infective juveniles (IJs) of eight different strains of heterorhabditid nematodes. The enzyme content ranged from 45.6 to 421.3 units/10(5) IJs with specific activity 34.0 to 82.6 units/mg protein. The isoenzyme patterns revealed the existence of two-slow-moving isoforms. Heterorhabditis bacteriophora AChE1A has been purified from the IJs of the heterorhabditid nematode strain of the highest enzymatic activity to homogeneity by ammonium sulfate precipitation, gel filtration on Sephacryl S-200 and DEAE-Sepharose. The specific activity of the purified enzyme was 1378.1 units/mg protein with purification fold 17.5 over crude extract. The enzyme has a pH optimum at 7.5. The optimum temperature for enzyme activity and stability was 35 degrees C. The activation energy was calculated to be 9.0 kcal/mol. The enzyme hydrolyzes acetylthiocholine (AcSCh), propionylthiocholine (PrSCh), S-butyrylthiocholine (BuSCh) and benzoylthiocholine (BzSCh) iodides with relative rate 100, 74.6, 41.7 and 22.2%, respectively. It displayed an apparent Michaelis-Menten behavior in the concentration range from 0.1 to 2 mM for the three former substrates with Km values 0.27, 0.42 and 0.59 mM, respectively. H. bacteriophora ChE1A is an AChE since it hydrolyzed AcSChI at higher rate than the other substrates and displayed excess substrate inhibition with AcSChI at concentrations over 2 mM. It was inhibited by eserine and BW284C51, but not by iso-OMPA. Its biochemical properties were compared with those reported for different species of insects as target hosts for heterorhabditid nematodes and animal parasitic nematodes.
Collapse
Affiliation(s)
- Magda A Mohamed
- Molecular Biology Department, National Research Centre, Cairo, Egypt.
| | | | | |
Collapse
|
21
|
Abstract
Acetylcholine is the major excitatory neurotransmitter controlling motor activities in nematodes, and the enzyme which hydrolyses and inactivates acetylcholine, acetylcholinesterase, is thus essential for regulation of cholinergic transmission. Different forms of acetylcholinesterase are encoded by multiple genes in nematodes, and analysis of the pattern of expression of these genes in Caenorhabditis elegans suggests that they perform non-redundant functions. In addition, many parasitic species which colonise host mucosal surfaces secrete hydrophilic variants of acetylcholinesterase, although the function of these enzymes is still unclear. Acetylcholinesterases have a history as targets for therapeutic agents against helminth parasites, but anti-cholinesterases have been used much more extensively as pesticides, for example to control crop damage and ectoparasitic infestation of livestock. The toxicity associated with these compounds (generally organophosphates and carbamates) has led to legislation to withdraw them from the market or restrict their use in many countries. Nevertheless, acetylcholinesterases provide a good example of a neuromuscular target enzyme in helminth parasites, and it may yet be possible to develop more selective inhibitors. In this article, we describe what is known about the structure and function of vertebrate cholinesterases, illustrate the molecular diversity and tissue distribution of these enzymes in C. elegans, and discuss to what extent this may represent a paradigm for nematodes in general.
Collapse
Affiliation(s)
- M E Selkirk
- Division of Cell and Molecular Biology, Imperial College London, London SW7 2AY, United Kingdom.
| | | | | |
Collapse
|
22
|
Pochanke V, Koller S, Dayer R, Hatak S, Ludewig B, Zinkernagel RM, Hengartner H, McCoy KD. Identification and characterization of a novel antigen from the nematodeNippostrongylus brasiliensis recognized by specific IgE. Eur J Immunol 2007; 37:1275-84. [PMID: 17429848 DOI: 10.1002/eji.200737135] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Identification and characterization of IgE-inducing antigens are important for elucidating the mechanisms involved in IgE-mediated immune responses in allergic diseases and parasite infections. While many allergens have been characterized, little is known about parasite antigens inducing specific IgE following infection. In order to identify antigens from the nematode Nippostrongylus brasiliensis, we generated an IgE-producing B cell hybridoma from N. brasiliensis-infected C57BL/6 mice and constructed a cDNA phage display library from N. brasiliensis. We successfully cloned and expressed an N. brasiliensis antigen (Nb-Ag1) that showed specific binding to anti-N. brasiliensis IgE. Nb-Ag1 localized to the pharynx of adult N. brasiliensis, suggesting that Nb-Ag1 is a potential pharyngeal gland antigen. Nb-Ag1-specific IgE could be detected in the serum of N. brasiliensis-infected mice, but only for a short time and only following a challenge infection. In contrast, local administration of Nb-Ag1 during primary, secondary and tertiary infections induced Nb-Ag1-specific IgE-mediated active cutaneous anaphylaxis. Therefore, amongst the high amounts of polyclonal total IgE, low levels of parasite-specific IgE responses are induced during primary helminth infections. Here, we show that even such low levels of parasite-specific IgE are sufficient to prime mast cells in vivo and mediate degranulation.
Collapse
Affiliation(s)
- Veronika Pochanke
- Institute for Experimental Immunology, University Hospital Zürich, Zürich, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Schulze H, Muench SB, Villatte F, Schmid RD, Bachmann TT. Insecticide detection through protein engineering of Nippostrongylus brasiliensis acetylcholinesterase B. Anal Chem 2007; 77:5823-30. [PMID: 16159111 DOI: 10.1021/ac050383p] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The sensitivity of acetylcholinesterase (AChE) biosensors for insecticide detection could be increased substantially by engineering AChE B of Nippostrongylus brasiliensis. The introduction of 10 single and 4 double mutations into the AChE peptide chain led to an increase in sensitivity to 10 of the 11 insecticides tested. The combination of three mutants with the wild-type enzyme in a multienzyme biosensor array enabled the detection of 11 out of the 14 most important organophosphates and carbamates at concentrations below 10 microg/kg, the maximum residue limit of infant food. The detection limit for pirimiphos methyl could be reduced from 10 microg/L to a value as low as 1 ng/L (3.5 x 10(-)(12) mol/L). The newly created biosensors exhibited an extraordinary high storage stability. There was no loss of sensitivity of N. brasiliensis AChE B, immobilized on screen-printed, disposable electrodes, even after 17-month storage at room temperature.
Collapse
Affiliation(s)
- Holger Schulze
- Institute of Technical Biochemistry, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany
| | | | | | | | | |
Collapse
|
24
|
Ball G, Selkirk ME, Knox DP. The effect of vaccination with a recombinant Nippostrongylus brasiliensis acetylcholinesterase on infection outcome in the rat. Vaccine 2007; 25:3365-72. [PMID: 17254675 DOI: 10.1016/j.vaccine.2006.12.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Revised: 12/11/2006] [Accepted: 12/21/2006] [Indexed: 11/26/2022]
Abstract
Nippostrongylus brasiliensis, the rodent hookworm, is a commonly used model of gastrointestinal nematode infection. This parasite, hookworms and several livestock nematode parasites of importance secrete distinct forms of acetylcholinesterases (AChE) that have been ascribed a putative parasite protective function. We tested the hypothesis that vaccination with the secreted enzyme would be deleterious to the parasite. Rats were immunised with a recombinant AChE isoform B via the subcutaneous, intra-peritoneal and intra-nasal routes using different adjuvants dependent on the mode of delivery and subsequently challenged with N. brasiliensis. Rats immunised via the subcutaneous and intra-nasal routes showed a modest but significant decrease in egg output of between 23 and 48%. This was mirrored by differences in the titre of specific antibody isotypes in the serum and mucosa following infection and serum from vaccinated animals was demonstrated to inhibit the activity of recombinant and native AChE. The utility of this model for future development of hookworm and veterinary nematode vaccines is discussed.
Collapse
Affiliation(s)
- G Ball
- University of Glasgow, Faculty of Veterinary Medicine, Glasgow G61 1QH, United Kingdom
| | | | | |
Collapse
|
25
|
Matthews JB, Lazari O, Davidson AJ, Warren S, Selkirk ME. A tryptophan amphiphilic tetramerization domain-containing acetylcholinesterase from the bovine lungworm, Dictyocaulus viviparus. Parasitology 2006; 133:381-7. [PMID: 16719958 DOI: 10.1017/s0031182006000345] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2006] [Revised: 03/14/2006] [Accepted: 03/14/2006] [Indexed: 11/05/2022]
Abstract
Acetylcholine (ACh) is one of an array of neurotransmitters used by invertebrates and, analogous to vertebrate nervous systems, acetylcholinesterase (AChE) regulates synaptic levels of this transmitter. Similar to other invertebrates, nematodes possess several AChE genes. This is in contrast to vertebrates, which have a single AChE gene, transcripts of which are alternatively spliced to produce different types of the enzyme which vary at their C-termini. Parasitic nematodes have a repertoire of AChE genes which include those encoding neuromuscular AChEs and those genes which code for secreted AChEs. The latter proteins exist as soluble monomers released by the parasite during infection and these AChE are distinct from those enzymes which the nematodes use for synaptic transmission in their neuromuscular system. Thus far, Dictyocaulus viviparus is the only animal-parasitic nematode for which distinct genes that encode both neuromuscular and secreted AChEs have been defined. Here, we describe the isolation and characterization of a cDNA encoding a putative neuromuscular AChE from D. viviparus which contains a tryptophan amphiphilic tetramerization (WAT) domain at its C-terminus analogous to the common 'tailed' AChE form found in the neuromuscular systems of vertebrates and in the ACE-1 AChE from Caenorhabditis elegans. This enzyme differs from the previously isolated, D. viviparus neuromuscular AChE (Dv-ACE-2), which is a glycosylphosphatidylinositol-anchored variant analogous to vertebrate 'hydrophobic' AChE.
Collapse
Affiliation(s)
- J B Matthews
- Division of Parasitology, Moredun Research Institute, Pentlands Science Park, Edinburgh.
| | | | | | | | | |
Collapse
|
26
|
Cottee PA, Abs EL-Osta YG, Nisbet AJ, Gasser RB. Ubiquitin-conjugating enzyme genes in Oesophagostomum dentatum. Parasitol Res 2006; 99:119-25. [PMID: 16518612 DOI: 10.1007/s00436-005-0111-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2005] [Accepted: 12/08/2005] [Indexed: 02/03/2023]
Abstract
Full-length genes representing different isoforms of the ubiquitin-conjugating enzyme UBC-2 were isolated from Oesophagostomum dentatum, cloned and sequenced. The alignment of their sequences (designated Od-ubc-2.1 to Od-ubc-2.3) revealed nucleotide variation at three positions within the predicted open reading frame of 444 bp. Substitutions were at positions 141 (A<-->G), 142 (A<-->G) and 296 (T<-->C). Both former substitutions resulted in amino acid changes from a glycine residue to an arginine residue, whereas the latter resulted in a change from isoleucine to threonine. Comparison of predicted OD-UBC-2 with UBC-2 (protein) homologues/orthologues from 12 other species representing nematodes, Drosophila melanogaster, Saccharomyces cerevisiae, mice and humans revealed identities between species varying from 77 to 100% at the amino acid level, and motifs associated with protein conformation and function were identified. While the function of a representative ubc-2 gene from O. dentatum could not be established in C. elegans, it is likely to play a key role in the catabolism of proteins and in the development of O. dentatum.
Collapse
Affiliation(s)
- Pauline A Cottee
- Department of Veterinary Science, The University of Melbourne, 250 Princes Highway, Werribee, Victoria 3030, Australia
| | | | | | | |
Collapse
|
27
|
Waibel M, Schulze H, Huber N, Bachmann TT. Screen-printed bienzymatic sensor based on sol–gel immobilized Nippostrongylus brasiliensis acetylcholinesterase and a cytochrome P450 BM-3 (CYP102-A1) mutant. Biosens Bioelectron 2006; 21:1132-40. [PMID: 15893924 DOI: 10.1016/j.bios.2005.04.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Revised: 04/21/2005] [Accepted: 04/21/2005] [Indexed: 10/25/2022]
Abstract
Here, we describe the development of a bi-enzymatic biosensor that simplifies the sample pretreatment steps for insecticide detection, and opens the way for a highly sensitive detection of phosphorothionates in food. These compounds evolve their inhibitory activity towards acetylcholinesterases (AChEs) only after oxidation, which is performed in vivo by P450 monooxygenases. Consequently, phosphorothionates require a suitable sample pretreatment by selective oxidation to be detectable in AChE based systems. In this study, enzymatic phosphorothionate activation and AChE inhibition were integrated in a single biosensor unit. A triple mutant of cytochrome P450 BM-3 (CYP 102-A1) and Nippostrongylus brasiliensis AChE (NbAChE) was immobilized using a fluoride catalyzed sol-gel process. Different sol-gel types were fabricated and characterized regarding enzyme loading capacity and enzyme activity containment. The enzyme sol-gel itself already proved to be suitable for the highly sensitive detection of paraoxon and parathion in a spectrometric assay. A method for screen-printing of this enzyme sol-gel on thick film electrodes was developed. Finally, amperometric biosensors containing coimmobilized NbAChE and the cytochrome P450 BM-3 mutant were produced and characterized with respect to signal stability, organophosphate detection, and storage stability. The detection limits achieved were 1 microg/L for paraoxon and 10 microg/L for parathion, which is according to EC regulations the highest tolerable pesticide concentration in infant food.
Collapse
Affiliation(s)
- Michael Waibel
- Institute of Technical Biochemistry, University of Stuttgart, Allmandring 31, D-70569 Stuttgart, Germany
| | | | | | | |
Collapse
|
28
|
Selkirk ME, Lazari O, Hussein AS, Matthews JB. Nematode acetylcholinesterases are encoded by multiple genes and perform non-overlapping functions. Chem Biol Interact 2005; 157-158:263-8. [PMID: 16243303 DOI: 10.1016/j.cbi.2005.10.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nematodes are unusual in that diverse molecular forms of acetylcholinesterase are the product of distinct genes. This is best characterised in the free living organism Caenorhabditis elegans, in which 3 genes are known to give rise to distinct enzymes, with a fourth likely to be non-functional. ACE-1 is an amphiphilic tetramer associated with a hydrophobic non-catalytic subunit, analogous to vertebrate T enzymes, whereas ACE-2 and ACE-3 are glycosylphosphatidylinositol-linked amphiphilic dimers. The different ace genes show distinct anatomical patterns of expression in muscles, sensory neurons and motor neurons, with only a few examples of coordinated expression. Clear homologues of ace-1 and ace-2 have now been isolated from a variety of parasitic nematodes, and the predicted proteins have very similar C-terminal amino acid sequences, implying an analogous means of anchorage to membranes. In addition to these membrane-bound enzymes, many parasitic nematodes which colonise mucosal surfaces secrete acetylcholinesterases to the external (host) environment. These hydrophilic enzymes are separately encoded in the genome, so that some parasites may thus have a total complement of six ace genes. The secretory enzymes have been characterised from the intestinal nematode Nippostrongylus brasiliensis and the lungworm Dictyocaulus viviparus. These show a number of common features, including a truncated C-terminus and an insertion at the molecular surface, when compared to other nematode acetylcholinesterases. Although the function of these enzymes has not been determined, they most likely alter host physiological responses to promote survival of the parasite.
Collapse
Affiliation(s)
- Murray E Selkirk
- Division of Cell and Molecular Biology, Imperial College London, London SW7 2AY, UK.
| | | | | | | |
Collapse
|
29
|
Madden KB, Yeung KA, Zhao A, Gause WC, Finkelman FD, Katona IM, Urban JF, Shea-Donohue T. Enteric nematodes induce stereotypic STAT6-dependent alterations in intestinal epithelial cell function. THE JOURNAL OF IMMUNOLOGY 2004; 172:5616-21. [PMID: 15100305 DOI: 10.4049/jimmunol.172.9.5616] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Infection with gastrointestinal nematodes exerts profound effects on both the immune and physiological responses of the host. We showed previously that the Th2 cytokines, IL-4 and IL-13, induce STAT6-dependent changes in intestinal epithelial cell permeability, absorption, and secretion that are similar to those observed in a secondary infection with Heligmosomoides polygyrus. In the current study we investigated whether nematode-induced effects on epithelial cell function were 1) generic, 2) dependent upon STAT6, and 3) attributable to direct effects on the epithelial cells themselves or mediated by effects on enteric nerves. Our results demonstrate that infection of BALB/c mice with three different gastrointestinal nematodes (H. polygyrus, Nippostrongylus brasiliensis, and Trichinella spiralis) alters intestinal epithelial cell function by decreasing resistance, glucose absorption, and secretory responses to 5-hydroxytryptamine and acetylcholine, two critical mediators in the submucosal reflex pathway. These modified responses are dependent on STAT6 and are the result of both direct effects and indirect effects mediated through enteric nerves.
Collapse
Affiliation(s)
- Kathleen B Madden
- Department of Pediatrics, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Lazari O, Selkirk ME, Ploeger HW, Matthews JB. A putative neuromuscular acetylcholinesterase gene from Dictyocaulus viviparus. Mol Biochem Parasitol 2004; 136:313-7. [PMID: 15478811 DOI: 10.1016/j.molbiopara.2004.04.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Ovadia Lazari
- Department of Veterinary Clinical Science, University of Liverpool, CH64 7TE, UK
| | | | | | | |
Collapse
|
31
|
Aboobaker AA, Blaxter ML. Functional genomics for parasitic nematodes and platyhelminths. Trends Parasitol 2004; 20:178-84. [PMID: 15099557 DOI: 10.1016/j.pt.2004.01.016] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- A Aziz Aboobaker
- Department of Integrative Biology, 3060 VLSB No. 3140, University of California-Berkeley, Berkeley, CA 94720-3140, USA
| | | |
Collapse
|
32
|
Lazari O, Hussein AS, Selkirk ME, Davidson AJ, Thompson FJ, Matthews JB. Cloning and expression of two secretory acetylcholinesterases from the bovine lungworm, Dictyocaulus viviparus. Mol Biochem Parasitol 2004; 132:83-92. [PMID: 14599668 DOI: 10.1016/j.molbiopara.2003.09.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe the molecular cloning, expression and biochemical characterisation of recombinant forms of two secreted acetylcholinesterases from adult Dictyocaulus viviparus. The two variants (designated Dv-ACE-1 and Dv-ACE-2) were 613 and 615 amino acids long and showed 94.7% identity to one another. The highest level of identity to other cholinesterases was with ACE-2 of Caenorhabditis elegans. Dv-ACE-1 and Dv-ACE-2 showed 48.0 and 47.7% identity to C. elegans ACE-2 over 577 amino acids, respectively. The primary structure of both enzymes showed conservation of the catalytic triad and of a tryptophan residue known to be critical for the choline-binding site, but differed in the number of potential glycosylation sites and at one amino acid in the peripheral anionic site. Southern blotting and PCR experiments indicated that the genes encoding these enzymes are distinct. When expressed in Pichia pastoris, the enzymes were active, but differed subtly in their biochemical characteristics. Both enzymes exhibited a preference for acetylcholine as substrate, but differed in the extent of excess substrate inhibition and in their optimal pH for activity. The lack of an obvious carboxy-terminal membrane anchor and the presence of an insertion at the molecular surface were other features which, thus far, appear to be characteristic of parasite secreted acetylcholinesterases.
Collapse
Affiliation(s)
- Ovadia Lazari
- Department of Veterinary Clinical Science and Animal Husbandry, University of Liverpool, Leahurst, CH64 7TE, South Wirral, UK
| | | | | | | | | | | |
Collapse
|
33
|
Abstract
PURPOSE OF REVIEW The mechanisms responsible for the Th2-mediated immune response to enteric nematode parasites are of interest for several reasons. First, intestinal parasites continue to be a major worldwide health issue. Second, the low incidence of parasite infection in industrial nations is cited as a factor in the increased prevalence of proinflammatory-based pathologies. Third, a seemingly paradoxical protection against Th2-mediated allergic reactions is afforded by helminth infection. This review focuses on studies that use enteral parasitic infections as a tool to investigate the functional consequences of upregulation of Th2-mediated immunity and that manipulate host-parasite interactions in an effort to identify mechanisms that can be exploited as potential therapeutic targets. RECENT FINDINGS Enteric helminth infection improved indices of inflammatory bowel disease in humans and murine models and diminished the allergy-induced changes in pulmonary function. There are emerging or enlarged roles for interleukin-10, interleukin-18, interleukin-9, chemokines, activation of nuclear factor-kappabeta, and factors that alter host resistance in the development of host immunity, and for interleukin-13Ralpha2 receptor in downregulating Th2 responses. As part of the growing appreciation for the contribution of nonimmune cells to parasite-induced changes in intestinal function, studies show that Th2 cytokines exert Stat6-dependent effects that promote worm expulsion. SUMMARY Further insight into the nature of host-parasite interactions, identification of the pathways and critical mediators that contribute to host resistance, identification of the factors that modulate susceptibility to infection, and the impact of enteric parasites on intestinal function hold much promise for development of novel therapeutic interventions.
Collapse
Affiliation(s)
- Terez Shea-Donohue
- US Department of Agriculture, Agricultural Research Service, Beltsville Human Nutrition Research Center, Nutrient Requirements and Functions Laboratory, Beltsville, Maryland 20705, USA.
| | | |
Collapse
|
34
|
Bentley GN, Jones AK, Agnew A. Mapping and sequencing of acetylcholinesterase genes from the platyhelminth blood fluke Schistosoma. Gene 2003; 314:103-12. [PMID: 14527722 DOI: 10.1016/s0378-1119(03)00709-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Acetylcholinesterase (AChE) on the surface of the parasitic blood fluke Schistosoma is the likely target for schistosomicidal anticholinesterases. Determination of the molecular structure of this drug target is key for the development of improved anticholinesterase drugs and potentially a novel vaccine. We have recently cloned the cDNA encoding the AChE from the human parasite Schistosoma haematobium and succeeded in expressing functional recombinant protein. We now describe the cloning and molecular characterisation of homologues from two other schistosome species-Schistosoma mansoni and Schistosoma bovis, which are important parasites of man and cattle, respectively, but which differ in their sensitivity to the therapeutic anticholinesterase metrifonate. Comparison of the deduced amino acid sequences revealed that the AChE from all three species posses a high degree of identity, with conservation of all of the residues known to be important for substrate binding and catalytic activity. Also conserved is a unique C-terminal domain which is unusual in that it lacks the consensus for GPI modification, even though the native protein is considered to be GPI-anchored. We have also established the AChE gene structures for all three species and cloned the complete gene for S. haematobium AChE. The gene structure is relatively complex, comprising nine coding exons; the location of the splice sites is identical in all three species, but the size of the introns varies considerably. The two C-terminal splicing sites that are conserved in all species are also present in Schistosoma, but a third C-terminal conserved splicing site which is located 11-13 amino acids upstream of the histidine of the catalytic triad in all invertebrate AChE genes characterised to date is absent. We discuss our findings in the context of the molecular phylogeny of the AChE genes and the potential application to the control of schistosomiasis.
Collapse
Affiliation(s)
- Geoffrey N Bentley
- The School of Biology, University of Leeds, West Yorkshire, LS2 9JT, Leeds, UK.
| | | | | |
Collapse
|