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Donnelly O, Mesquita S, Archer J, Ali SM, Bartonicek Z, Lugli EB, Webster BL. Refining the Schistosoma haematobium recombinase polymerase amplification (Sh-RPA) assay: moving towards point-of-care use in endemic settings. Parasit Vectors 2024; 17:321. [PMID: 39068490 PMCID: PMC11283713 DOI: 10.1186/s13071-024-06380-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Accepted: 06/26/2024] [Indexed: 07/30/2024] Open
Abstract
BACKGROUND Urogenital schistosomiasis is caused by the parasitic trematode Schistosoma haematobium. Sensitive and specific point-of-care diagnostics are needed for elimination of this disease. Recombinase polymerase amplification (RPA) assays meet these criteria, and an assay to diagnose S. haematobium has been developed (Sh-RPA). However, false-positive results can occur, and optimisation of reaction conditions to mitigate these is needed. Ease of use and compatibility of DNA extraction methods must also be considered. METHODS Using synthetic DNA, S. haematobium genomic DNA (gDNA), and urine samples from clinical cases, Sh-RPA reactions incorporating different betaine concentrations (0 M, 1 M, 2.5 M, 12.5 M) and the sample-to-water ratios were tested to determine effects on assay specificity and sensitivity. In addition, five commercial DNA extraction kits suitable for use in resource-limited settings were used to obtain gDNA from single S. haematobium eggs and evaluated in terms of DNA quality, quantity, and compatibility with the Sh-RPA assay. All samples were also evaluated by quantitative polymerase chain reaction (qPCR) to confirm DNA acquisition. RESULTS The analytical sensitivity of the Sh-RPA with all betaine concentrations was ≥ 10 copies of the synthetic Dra1 standard and 0.1 pg of S. haematobium gDNA. The addition of betaine improved Sh-RPA assay specificity in all reaction conditions, and the addition of 2.5 M of betaine together with the maximal possible sample volume of 12.7 µl proved to be the optimum reaction conditions. DNA was successfully isolated from a single S. haematobium egg using all five commercial DNA extraction kits, but the Sh-RPA performance of these kits varied, with one proving to be incompatible with RPA reactions. CONCLUSIONS The addition of 2.5 M of betaine to Sh-RPA reactions improved reaction specificity whilst having no detrimental effect on sensitivity. This increases the robustness of the assay, advancing the feasibility of using the Sh-RPA assay in resource-limited settings. The testing of commercial extraction kits proved that crude, rapid, and simple methods are sufficient for obtaining DNA from single S. haematobium eggs, and that these extracts can be used with Sh-RPA in most cases. However, the observed incompatibility of specific kits with Sh-RPA highlights the need for each stage of a molecular diagnostic platform to be robustly tested prior to implementation.
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Affiliation(s)
- Owain Donnelly
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- Malaria Biochemistry Laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - Silvia Mesquita
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- René Rachou Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil
| | - John Archer
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- Department of Parasitology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Said M Ali
- Public Health Laboratory-Ivo de Carneri, P.O. Box 122, Chake-Chake, Pemba, United Republic of Tanzania
| | - Zikmund Bartonicek
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Elena B Lugli
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK
| | - Bonnie L Webster
- Wolfson Wellcome Biomedical Laboratories, Department of Science, Natural History Museum, Cromwell Road, London, SW7 5BD, UK.
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EF24, a schistosomicidal curcumin analog: Insights from its synthesis and phenotypic, biochemical and cytotoxic activities. Chem Biol Interact 2022; 368:110191. [DOI: 10.1016/j.cbi.2022.110191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 09/18/2022] [Accepted: 09/20/2022] [Indexed: 12/22/2022]
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Rahman MM, McFadden G, Ruthel G, Herbert DR, Freedman BD, Greenberg RM, Bais S. Oncolytic Myxoma virus infects and damages the tegument of the human parasitic flatworm Schistosoma mansoni. Exp Parasitol 2022; 239:108263. [PMID: 35598646 PMCID: PMC11003549 DOI: 10.1016/j.exppara.2022.108263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/13/2022] [Accepted: 04/19/2022] [Indexed: 11/23/2022]
Abstract
Schistosomiasis is a devastating disease caused by parasitic flatworms of the genus Schistosoma. Praziquantel (PZQ), the current treatment of choice, is ineffective against immature worms and cannot prevent reinfection. The continued reliance on a single drug for treatment increases the risk of the development of PZQ-resistant parasites. Reports of PZQ insusceptibility lends urgency to the need for new therapeutics. Here, we report that Myxoma virus (MYXV), an oncolytic pox virus which is non-pathogenic in all mammals except leporids, infects and replicates in S. mansoni schistosomula, juveniles, and adult male and female worms. MYXV infection results in the shredding of the tegument and reduced egg production in vitro, identifying MYXV as the first viral pathogen of schistosomes. MYXV is currently in preclinical studies to manage multiple human cancers, supporting its use in human therapeutics. Our findings raise the exciting possibility that MYXV virus represents a novel and safe class of potential anthelmintic therapeutics.
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Affiliation(s)
- Masmudur M Rahman
- Center for Immunotherapy, Vaccines and Virotherapy, Bio design Institute, Arizona State University, Tempe, AZ, USA
| | - Grant McFadden
- Center for Immunotherapy, Vaccines and Virotherapy, Bio design Institute, Arizona State University, Tempe, AZ, USA
| | - Gordon Ruthel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - De'Broski R Herbert
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Bruce D Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Robert M Greenberg
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Swarna Bais
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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Yeh YT, Skinner DE, Criado-Hidalgo E, Chen NS, Garcia-De Herreros A, El-Sakkary N, Liu L, Zhang S, Kandasamy A, Chien S, Lasheras JC, del Álamo JC, Caffrey CR. Biomechanical interactions of Schistosoma mansoni eggs with vascular endothelial cells facilitate egg extravasation. PLoS Pathog 2022; 18:e1010309. [PMID: 35316298 PMCID: PMC8939816 DOI: 10.1371/journal.ppat.1010309] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 01/26/2022] [Indexed: 12/03/2022] Open
Abstract
The eggs of the parasitic blood fluke, Schistosoma, are the main drivers of the chronic pathologies associated with schistosomiasis, a disease of poverty afflicting approximately 220 million people worldwide. Eggs laid by Schistosoma mansoni in the bloodstream of the host are encapsulated by vascular endothelial cells (VECs), the first step in the migration of the egg from the blood stream into the lumen of the gut and eventual exit from the body. The biomechanics associated with encapsulation and extravasation of the egg are poorly understood. We demonstrate that S. mansoni eggs induce VECs to form two types of membrane extensions during encapsulation; filopodia that probe eggshell surfaces and intercellular nanotubes that presumably facilitate VEC communication. Encapsulation efficiency, the number of filopodia and intercellular nanotubes, and the length of these structures depend on the egg’s vitality and, to a lesser degree, its maturation state. During encapsulation, live eggs induce VEC contractility and membranous structures formation in a Rho/ROCK pathway-dependent manner. Using elastic hydrogels embedded with fluorescent microbeads as substrates to culture VECs, live eggs induce VECs to exert significantly greater contractile forces during encapsulation than dead eggs, which leads to 3D deformations on both the VEC monolayer and the flexible substrate underneath. These significant mechanical deformations cause the VEC monolayer tension to fluctuate with the eventual rupture of VEC junctions, thus facilitating egg transit out of the blood vessel. Overall, our data on the mechanical interplay between host VECs and the schistosome egg improve our understanding of how this parasite manipulates its immediate environment to maintain disease transmission. Schistosomiasis, which infects over 200 million people, is a painful disease of poverty that is caused by inflammatory responses to the Schistosoma blood fluke’s eggs. To continue the parasite’s life cycle, eggs must escape the blood vessels and migrate through tissues of the host to the alimentary canal for exit into the environment. The biomechanical processes that help the immobile eggs to cross the blood vessel’s vascular endothelial cells (VECs) as the first step in this migration are not understood. We found that live but not dead eggs induce VECs to crawl over and encapsulate them. VECs in contact with live eggs make membranous extensions (filopodia) to explore the egg’s surface and also form long intercellular nanotubes to communicate with neighboring cells. VECs stimulate particular (Rho/ROCK) biochemical pathways to increase cell contractility and the forces generated are large enough to eventually break the junctions between cells and allow passage of the eggs into the underlying tissue. Our findings show how schistosome eggs activate and interact with VECs to initiate their escape from the bloodstream.
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Affiliation(s)
- Yi-Ting Yeh
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
| | - Danielle E. Skinner
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Ernesto Criado-Hidalgo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Natalie Shee Chen
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Antoni Garcia-De Herreros
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Nelly El-Sakkary
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Lawrence Liu
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
| | - Shun Zhang
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Adithan Kandasamy
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
- Center for Cardiovascular Biology, University of Washington, Seattle Washington, United States of America
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle Washington, United States of America
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Juan C. Lasheras
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Institute of Engineering in Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Juan C. del Álamo
- Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Mechanical Engineering, University of Washington, Seattle, Washington, United States of America
- Center for Cardiovascular Biology, University of Washington, Seattle Washington, United States of America
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle Washington, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
| | - Conor R. Caffrey
- Center for Discovery and Innovation in Parasitic Diseases (CDIPD), Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, United States of America
- * E-mail: (YTY); (JCdA); (CRC)
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Li H, Hambrook JR, Pila EA, Gharamah AA, Fang J, Wu X, Hanington P. Coordination of humoral immune factors dictates compatibility between Schistosoma mansoni and Biomphalaria glabrata. eLife 2020; 9:e51708. [PMID: 31916937 PMCID: PMC6970513 DOI: 10.7554/elife.51708] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 01/07/2020] [Indexed: 01/09/2023] Open
Abstract
Immune factors in snails of the genus Biomphalaria are critical for combating Schistosoma mansoni, the predominant cause of human intestinal schistosomiasis. Independently, many of these factors play an important role in, but do not fully define, the compatibility between the model snail B. glabrata, and S. mansoni. Here, we demonstrate association between four previously characterized humoral immune molecules; BgFREP3, BgTEP1, BgFREP2 and Biomphalysin. We also identify unique immune determinants in the plasma of S. mansoni-resistant B. glabrata that associate with the incompatible phenotype. These factors coordinate to initiate haemocyte-mediated destruction of S. mansoni sporocysts via production of reactive oxygen species. The inclusion of BgFREP2 in a BgFREP3-initiated complex that also includes BgTEP1 almost completely explains resistance to S. mansoni in this model. Our study unifies many independent lines of investigation to provide a more comprehensive understanding of the snail immune system in the context of infection by this important human parasite.
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Affiliation(s)
- Hongyu Li
- Ocean CollegeBeibu Gulf UniversityQinzhouChina
- School of Public HealthUniversity of AlbertaEdmontonCanada
| | | | | | | | - Jing Fang
- Ocean CollegeBeibu Gulf UniversityQinzhouChina
- School of Public HealthUniversity of AlbertaEdmontonCanada
| | - Xinzhong Wu
- Ocean CollegeBeibu Gulf UniversityQinzhouChina
- College of Animal SciencesZhejiang UniversityHangzhouChina
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Hambrook JR, Gharamah AA, Pila EA, Hussein S, Hanington PC. Biomphalaria glabrata Granulin Increases Resistance to Schistosoma mansoni Infection in Several Biomphalaria Species and Induces the Production of Reactive Oxygen Species by Haemocytes. Genes (Basel) 2019; 11:E38. [PMID: 31905675 PMCID: PMC7017051 DOI: 10.3390/genes11010038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/16/2019] [Accepted: 12/27/2019] [Indexed: 12/11/2022] Open
Abstract
Gastropod molluscs, which have co-evolved with parasitic digenean trematodes for millions of years, utilize circulating heamocytes as the primary method of containing and killing these invading parasites. In order to do so, they must generate suitable amounts of haemocytes that are properly armed to kill parasitic worms. One method by which they generate the haemocytes required to initiate the appropriate cell mediated immune response is via the production and post-translational processing of granulins. Granulins are an evolutionarily conserved family of growth factors present in the majority of eukaryotic life forms. In their pro-granulin form, they can elicit cellular replication and differentiation. The pro-granulins can be further processed by elastase to generate smaller granulin fragments that have been shown to functionally differ from the pro-granulin precursor. In this study, we demonstrate that in vivo addition of Biomphalaria glabrata pro-granulin (BgGRN) can reduce Schistosoma mansoni infection success in numerous Biomphalaria sp. when challenged with different S. mansoni strains. We also demonstrate that cleavage of BgGRN into individual granulin subunits by elastase results in the stimulation of haemocytes to produce reactive oxygen species.
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Affiliation(s)
- Jacob R. Hambrook
- School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada; (J.R.H.); (A.A.G.); (E.A.P.)
| | - Abdullah A. Gharamah
- School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada; (J.R.H.); (A.A.G.); (E.A.P.)
| | - Emmanuel A. Pila
- School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada; (J.R.H.); (A.A.G.); (E.A.P.)
| | - Solomon Hussein
- Department of Biological Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada;
| | - Patrick C. Hanington
- School of Public Health, University of Alberta, Edmonton, AB T6G 2R3, Canada; (J.R.H.); (A.A.G.); (E.A.P.)
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Sotillo J, Pearson MS, Loukas A. Trematode Genomics and Proteomics. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1154:411-436. [PMID: 31297769 DOI: 10.1007/978-3-030-18616-6_13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Trematode infections are among the most neglected tropical diseases despite their worldwide distribution and extraordinary ability to parasitise many different host species and host tissues. Furthermore, these parasites are of great socioeconomic, medical, veterinary and agricultural importance. During the last 10 years, there have been increasing efforts to overcome the lack of information on different "omic" resources such as proteomics and genomics. Herein, we focus on the recent advances in genomics and proteomics from trematodes of human importance, including liver, blood, intestinal and lung flukes. We also provide information on the latest technologies applied to study the biology of trematodes as well as on the resources available for the study of the molecular aspects of this group of helminths.
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Affiliation(s)
- Javier Sotillo
- Centre for Molecular Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia.
| | - Mark S Pearson
- Centre for Molecular Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - Alex Loukas
- Centre for Molecular Therapeutics, Australian Institute for Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
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A metalloprotease produced by larval Schistosoma mansoni facilitates infection establishment and maintenance in the snail host by interfering with immune cell function. PLoS Pathog 2018; 14:e1007393. [PMID: 30372490 PMCID: PMC6224180 DOI: 10.1371/journal.ppat.1007393] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 11/08/2018] [Accepted: 10/08/2018] [Indexed: 11/18/2022] Open
Abstract
Metalloproteases (MPs) have demonstrated roles in immune modulation. In some cases, these enzymes are produced by parasites to influence host immune responses such that parasite infection is facilitated. One of the best examples of parasite-mediated immune modulation is the matrix metalloprotease (MMP) leishmanolysin (Gp63), which is produced by species of the genus Leishmania to evade killing by host macrophages. Leishmanolysin-like proteins appear to be quite common in many invertebrates, however our understanding of the functions of these non-leishmania enzymes is limited. Numerous proteomic and transcriptomic screens of schistosomes, at all life cycle stages of the parasite, have identified leishmanolysin-like MPs as being present in abundance; with the highest levels being found during the intramolluscan larval stages and being produced by cercaria. This study aims to functionally characterize a Schistosoma mansoni variant of leishmanolysin that most resembles the enzyme produced by Leishmania, termed SmLeish. We demonstrate that SmLeish is an important component of S. mansoni excretory/secretory (ES) products and is produced by the sporocyst during infection. The presence of SmLeish interferes with the migration of Biomphalaria glabrata haemocytes, and causes them to present a phenotype that is less capable of sporocyst encapsulation. Knockdown of SmLeish in S. mansoni miracidia prior to exposure to susceptible B. glabrata reduces miracidia penetration success, causes a delay in reaching patent infection, and lowers cercaria output from infected snails. Parasitic flatworms, or digenetic trematodes, cause a wide range of diseases of both medical and agricultural importance. Nearly all species of digenea require specific species of snail for their larval development and transmission. The factors underpinning snail host specificity and how they dictate infection establishment and maintenance are interesting areas of research, both from the perspective of evolutionary immunology and potential application in the design of tools that aim to prevent trematode transmission. Currently, our understanding of snail-trematode associations is one-sided, being predominantly derived from studies that have focused on the snail immune response, with almost nothing known about how the parasite facilitates infection. Metalloproteases, such as leishmanolysin, are proteolytic enzymes; some of which are produced by parasites to influence host immune responses and facilitate parasite success upon encountering the host defense response. Here, we have functionally characterized a leishmanolysin-like metalloprotease (SmLeish) from Schistosoma mansoni, a causative agent of human schistosomiasis, which afflicts over 260 million people globally. We demonstrate that SmLeish is associated with developing sporocysts and is also located in S. mansoni excretory/secretory products and interferes with snail haemocyte morphology and migration. Knockdown of SmLeish in S. mansoni miracidia prior to exposure to Biomphalaria glabrata snails reduces miracidia penetration success, delays attainment of patent infections, and lowers cercaria output from infected snails.
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Bais S, Berry CT, Liu X, Ruthel G, Freedman BD, Greenberg RM. Atypical pharmacology of schistosome TRPA1-like ion channels. PLoS Negl Trop Dis 2018; 12:e0006495. [PMID: 29746471 PMCID: PMC5963811 DOI: 10.1371/journal.pntd.0006495] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/22/2018] [Accepted: 05/02/2018] [Indexed: 12/21/2022] Open
Abstract
Parasitic flatworms of the genus Schistosoma cause schistosomiasis, a neglected tropical disease estimated to affect over 200 million people worldwide. Praziquantel is the only antischistosomal currently available for treatment, and there is an urgent need for new therapeutics. Ion channels play key roles in physiology and are targets for many anthelmintics, yet only a few representatives have been characterized in any detail in schistosomes and other parasitic helminths. The transient receptor potential (TRP) channel superfamily comprises a diverse family of non-selective cation channels that play key roles in sensory transduction and a wide range of other functions. TRP channels fall into several subfamilies. Members of both the TRPA and TRPV subfamilies transduce nociceptive and inflammatory signals in mammals, and often also respond to chemical and thermal signals. We previously showed that although schistosomes contain no genes predicted to encode TRPV channels, TRPV1-selective activators such as capsaicin and resiniferatoxin elicit dramatic hyperactivity in adult worms and schistosomula. Surprisingly, this response requires expression of a S. mansoni TRPA1-like orthologue (SmTRPA). Here, we show that capsaicin induces a rise in intracellular Ca2+ in mammalian cells expressing either SmTRPA or a S. haematobium TRPA1 orthologue (ShTRPA). We also test SmTRPA and ShTRPA responses to various TRPV1 and TRPA1 modulators. Interestingly, in contrast to SmTRPA, ShTRPA is not activated by the TRPA1 activator AITC (allyl isothiocyanate), nor do S. haematobium adult worms respond to this compound, a potentially intriguing species difference. Notably, 4-hydroxynonenal (4-HNE), a host-derived, inflammatory product that directly activates mammalian TRPA1, also activates both SmTRPA and ShTRPA. Our results point to parasite TRPA1-like channels which exhibit atypical, mixed TRPA1/TRPV1-like pharmacology, and which may also function to transduce endogenous host signals. Schistosomes are parasitic flatworms that infect hundreds of millions of people worldwide. They cause schistosomiasis, a disease with major consequences for human health and economic development. There is only a single drug available for treatment and control of this highly prevalent disease, and there is an urgent need for development of new treatments. TRP ion channels play key roles in sensory (and other) functions. One type of TRP channel, TRPV1, is activated by capsaicin, the active ingredient in hot peppers. However, schistosomes do not have any TRPV-like channels. Nonetheless, we previously showed that capsaicin and similar compounds induce dramatic hyperactivity in schistosomes, and that this response is abolished by suppressing expression of SmTRPA, a schistosome TRPA1-like channel. Mammalian TRPA1 channels are not sensitive to capsaicin. Here, we show that the SmTRPA channel itself responds to capsaicin, resulting in an influx of Ca2+ into cells. ShTRPA, a TRPA1-like channel from another schistosome, S. haematobium, is also sensitive to capsaicin. Thus, the pharmacology of schistosome TRPA1 channels apparently differs from that of host mammalian channels, a characteristic that could indicate mixed TRPA/TRPV functionality and might be exploitable for development of new antischistosomal drugs. Furthermore, we show that schistosome TRPA1-like channels are activated by host-derived compounds, perhaps indicating a mechanism by which the parasite can respond to host signals.
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Affiliation(s)
- Swarna Bais
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Corbett T. Berry
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Xiaohong Liu
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gordon Ruthel
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Bruce D. Freedman
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Robert M. Greenberg
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Henein L, Cody JJ, Hsieh MH. An enduring legacy of discovery: Margaret Stirewalt. PLoS Negl Trop Dis 2017; 11:e0005714. [PMID: 28817582 PMCID: PMC5560522 DOI: 10.1371/journal.pntd.0005714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Lucie Henein
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - James J. Cody
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - Michael H. Hsieh
- Biomedical Research Institute, Rockville, Maryland, United States of America
- Division of Urology, Children’s National Health System, Washington, D.C., United States of America
- Department of Urology, The George Washington University, Washington, D.C., United States of America
- * E-mail:
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