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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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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.
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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:
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3
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Du X, Jones MK, Nawaratna SSK, Ranasinghe S, Xiong C, Cai P, McManus DP, You H. Gene Expression in Developmental Stages of Schistosoma japonicum Provides Further Insight into the Importance of the Schistosome Insulin-Like Peptide. Int J Mol Sci 2019; 20:ijms20071565. [PMID: 30925781 PMCID: PMC6480100 DOI: 10.3390/ijms20071565] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/11/2019] [Accepted: 03/22/2019] [Indexed: 12/11/2022] Open
Abstract
We showed previously that the Schistosoma japonicum insulin-like peptide (SjILP) binds the worm insulin receptors, thereby, activating the parasite’s insulin pathway and emphasizing its important role in regulating uptake of glucose, a nutrient essential for parasite survival. Here we show that SjILP is differentially expressed in the schistosome life cycle and is especially highly transcribed in eggs, miracidia, and adult female worms. RNA inference was employed to knockdown SjILP in adults in vitro, with suppression confirmed by significantly reduced protein production, declined adenosine diphosphate levels, and reduction in glucose consumption. Immunolocalization showed that SjILP is located to lateral gland cells of mature intra-ovular miracidia in the schistosome egg, and is distributed on the ciliated epithelium and internal cell masses of newly transformed miracidia. In schistosomula, SjILP is present on the tegument in two antero-lateral points, indicating highly polarized expression during cercarial transformation. Analysis of serum from S. japonicum-infected mice by ELISA using a recombinant form of SjILP as an antigen revealed IgG immunoreactivity to this molecule at 7 weeks post-infection indicating it is likely secreted from mature eggs into the host circulation. These findings provide further insights on ILP function in schistosomes and its essential roles in parasite survival and growth in different development stages.
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Affiliation(s)
- Xiaofeng Du
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
| | - Malcolm K Jones
- School of Veterinary Science, The University of Queensland, Gatton 4343, Australia.
| | - Sujeevi S K Nawaratna
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
- School of Medicine, Griffith University, Gold Coast 4222, Australia.
| | - Shiwanthi Ranasinghe
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
| | - Chunrong Xiong
- Key Laboratory of National Health and Family Planning Commission on Parasitic Disease Control and Prevention, Jiangsu Provincial Key Laboratory on Parasite and Vector Control Technology, Jiangsu Institute of Parasitic Diseases, Wuxi 214000, China.
| | - Pengfei Cai
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
| | - Donald P McManus
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
| | - Hong You
- Molecular Parasitology Laboratory, QIMR Berghofer Medical Research Institute, Queensland 4006, Australia.
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Suppression of Schistosoma japonicum Acetylcholinesterase Affects Parasite Growth and Development. Int J Mol Sci 2018; 19:ijms19082426. [PMID: 30115897 PMCID: PMC6121427 DOI: 10.3390/ijms19082426] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 08/10/2018] [Accepted: 08/11/2018] [Indexed: 12/17/2022] Open
Abstract
To further investigate the importance of Schistosoma japonicum acetylcholinesterase (SjAChE) in cholinergic signaling for parasite growth and development, we used RNA interference (RNAi) to knock-down its expression in adults and eggs in vitro. This resulted in its reduced transcription but also expression of other important genes involved both in cholinergic signaling and glucose uptake were impacted substantially. Significant decreases in AChE protein expression, AChE enzymatic activity, and glucose uptake were observed in the SjAChE-knockdown parasites compared with luciferase controls. In vaccine/challenge experiments, we found that immunization of mice with recombinant SjAChE (rSjAChE) expressed in Escherichia coli elicited reductions in male worm numbers (33%), liver granuloma density (41%), and reduced numbers of mature intestinal eggs (73%) in the vaccinated group compared with the control group. These results indicate AChE plays an important role in the metabolism of male worms, and impacts indirectly on female fecundity leading to increased numbers of immature eggs being released and reduced sizes of liver granulomas. Furthermore, cytokine analysis showed that immunization of mice with rSjAChE elicited a predominantly Th1-type immune response characterized by increased production of IFNγ in splenic CD4+ T cells of vaccinated mice. The study confirms the potential of SjAChE as a vaccine/drug candidate against zoonotic schistosomiasis japonica.
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Suttiprapa S, Rinaldi G, Tsai IJ, Mann VH, Dubrovsky L, Yan HB, Holroyd N, Huckvale T, Durrant C, Protasio AV, Pushkarsky T, Iordanskiy S, Berriman M, Bukrinsky MI, Brindley PJ. HIV-1 Integrates Widely throughout the Genome of the Human Blood Fluke Schistosoma mansoni. PLoS Pathog 2016; 12:e1005931. [PMID: 27764257 PMCID: PMC5072744 DOI: 10.1371/journal.ppat.1005931] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/13/2016] [Indexed: 11/18/2022] Open
Abstract
Schistosomiasis is the most important helminthic disease of humanity in terms of morbidity and mortality. Facile manipulation of schistosomes using lentiviruses would enable advances in functional genomics in these and related neglected tropical diseases pathogens including tapeworms, and including their non-dividing cells. Such approaches have hitherto been unavailable. Blood stream forms of the human blood fluke, Schistosoma mansoni, the causative agent of the hepatointestinal schistosomiasis, were infected with the human HIV-1 isolate NL4-3 pseudotyped with vesicular stomatitis virus glycoprotein. The appearance of strong stop and positive strand cDNAs indicated that virions fused to schistosome cells, the nucleocapsid internalized and the RNA genome reverse transcribed. Anchored PCR analysis, sequencing HIV-1-specific anchored Illumina libraries and Whole Genome Sequencing (WGS) of schistosomes confirmed chromosomal integration; >8,000 integrations were mapped, distributed throughout the eight pairs of chromosomes including the sex chromosomes. The rate of integrations in the genome exceeded five per 1,000 kb and HIV-1 integrated into protein-encoding loci and elsewhere with integration bias dissimilar to that of human T cells. We estimated ~ 2,100 integrations per schistosomulum based on WGS, i.e. about two or three events per cell, comparable to integration rates in human cells. Accomplishment in schistosomes of post-entry processes essential for HIV-1replication, including integrase-catalyzed integration, was remarkable given the phylogenetic distance between schistosomes and primates, the natural hosts of the genus Lentivirus. These enigmatic findings revealed that HIV-1 was active within cells of S. mansoni, and provided the first demonstration that HIV-1 can integrate into the genome of an invertebrate.
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Affiliation(s)
- Sutas Suttiprapa
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
- Department of Microbiology, Faculty of Science, Mahidol University, Phyathai, Rachthewee, Bangkok
- Department of Pathology, Faculty of Medicine, Khon Kaen University, Muang Khon Kaen, Thailand
| | - Gabriel Rinaldi
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Isheng J. Tsai
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
- Biodiversity Research Center, Academia Sinica, Taipei, Taiwan
| | - Victoria H. Mann
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
| | - Larisa Dubrovsky
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
| | - Hong-bin Yan
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
- Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Xujiaping 1, Lanzhou, Gansu, The People's Republic of China
| | - Nancy Holroyd
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Thomas Huckvale
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Caroline Durrant
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Anna V. Protasio
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Tatiana Pushkarsky
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
| | - Sergey Iordanskiy
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
- National Center for Biodefense and Infectious Diseases, School of Systems Biology, George Mason University, Manassas, Virginia, United States of America
| | - Matthew Berriman
- Wellcome Trust Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Michael I. Bukrinsky
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
| | - Paul J. Brindley
- Department of Microbiology, Immunology & Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, The George Washington University, Washington, DC, United States of America
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Skinner-Adams TS, Sumanadasa SD, Fisher GM, Davis RA, Doolan DL, Andrews KT. Defining the targets of antiparasitic compounds. Drug Discov Today 2016; 21:725-39. [DOI: 10.1016/j.drudis.2016.01.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 12/04/2015] [Accepted: 01/07/2016] [Indexed: 10/22/2022]
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Pseudotyped murine leukemia virus for schistosome transgenesis: approaches, methods and perspectives. Transgenic Res 2014; 23:539-56. [DOI: 10.1007/s11248-013-9779-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
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Rinaldi G, Eckert SE, Tsai IJ, Suttiprapa S, Kines KJ, Tort JF, Mann VH, Turner DJ, Berriman M, Brindley PJ. Germline transgenesis and insertional mutagenesis in Schistosoma mansoni mediated by murine leukemia virus. PLoS Pathog 2012; 8:e1002820. [PMID: 22911241 PMCID: PMC3406096 DOI: 10.1371/journal.ppat.1002820] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 06/11/2012] [Indexed: 12/11/2022] Open
Abstract
Functional studies will facilitate characterization of role and essentiality of newly available genome sequences of the human schistosomes, Schistosoma mansoni, S. japonicum and S. haematobium. To develop transgenesis as a functional approach for these pathogens, we previously demonstrated that pseudotyped murine leukemia virus (MLV) can transduce schistosomes leading to chromosomal integration of reporter transgenes and short hairpin RNA cassettes. Here we investigated vertical transmission of transgenes through the developmental cycle of S. mansoni after introducing transgenes into eggs. Although MLV infection of schistosome eggs from mouse livers was efficient in terms of snail infectivity, >10-fold higher transgene copy numbers were detected in cercariae derived from in vitro laid eggs (IVLE). After infecting snails with miracidia from eggs transduced by MLV, sequencing of genomic DNA from cercariae released from the snails also revealed the presence of transgenes, demonstrating that transgenes had been transmitted through the asexual developmental cycle, and thereby confirming germline transgenesis. High-throughput sequencing of genomic DNA from schistosome populations exposed to MLV mapped widespread and random insertion of transgenes throughout the genome, along each of the autosomes and sex chromosomes, validating the utility of this approach for insertional mutagenesis. In addition, the germline-transmitted transgene encoding neomycin phosphotransferase rescued cultured schistosomules from toxicity of the antibiotic G418, and PCR analysis of eggs resulting from sexual reproduction of the transgenic worms in mice confirmed that retroviral transgenes were transmitted to the next (F1) generation. These findings provide the first description of wide-scale, random insertional mutagenesis of chromosomes and of germline transmission of a transgene in schistosomes. Transgenic lines of schistosomes expressing antibiotic resistance could advance functional genomics for these significant human pathogens. DATABASE ACCESSION: Sequence data from this study have been submitted to the European Nucleotide Archive (http://www.ebi.ac.uk/embl) under accession number ERP000379.
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Affiliation(s)
- Gabriel Rinaldi
- Department of Microbiology, Immunology & Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC, United States of America
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Sabine E. Eckert
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Oxford Nanopore Technologies, Oxford, United Kingdom
| | - Isheng J. Tsai
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Sutas Suttiprapa
- Department of Microbiology, Immunology & Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC, United States of America
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kristine J. Kines
- Department of Microbiology, Immunology & Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC, United States of America
- Tulane Cancer Center, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - José F. Tort
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Victoria H. Mann
- Department of Microbiology, Immunology & Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC, United States of America
| | - Daniel J. Turner
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
- Oxford Nanopore Technologies, Oxford, United Kingdom
| | - Matthew Berriman
- The Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, United Kingdom
| | - Paul J. Brindley
- Department of Microbiology, Immunology & Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, Washington, DC, United States of America
- Research Center for Neglected Diseases of Poverty, The George Washington University, Washington, DC, United States of America
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Alrefaei YN, Okatcha TI, Skinner DE, Brindley PJ. Progress with schistosome transgenesis. Mem Inst Oswaldo Cruz 2012; 106:785-93. [PMID: 22124549 DOI: 10.1590/s0074-02762011000700002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 05/20/2011] [Indexed: 11/22/2022] Open
Abstract
Genome sequences for Schistosoma japonicum and Schistosoma mansoni are now available. The schistosome genome encodes ~13,000 protein encoding genes for which the function of only a minority is understood. There is a valuable role for transgenesis in functional genomic investigations of these new schistosome gene sequences. In gain-of-function approaches, transgenesis can lead to integration of transgenes into the schistosome genome which can facilitate insertional mutagenesis screens. By contrast, transgene driven, vector-based RNA interference (RNAi) offers powerful loss-of-function manipulations. Our laboratory has focused on development of tools to facilitate schistosome transgenesis. We have investigated the utility of retroviruses and transposons to transduce schistosomes. Vesicular stomatitis virus glycoprotein (VSVG) pseudotyped murine leukemia virus (MLV) can transduce developmental stages of S. mansoni including eggs. We have also observed that the piggyBac transposon is transpositionally active in schistosomes. Approaches with both VSVG-MLV and piggyBac have resulted in somatic transgenesis and have lead to integration of active reporter transgenes into schistosome chromosomes. These findings provided the first reports of integration of reporter transgenes into schistosome chromosomes. Experience with these systems is reviewed herewith, along with findings with transgene mediated RNAi and germ line transgenesis, in addition to pioneering and earlier reports of gene manipulation for schistosomes.
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Affiliation(s)
- Yousef Noori Alrefaei
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University Medical Center, Washington, DC, USA
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Skinner DE, Rinaldi G, Suttiprapa S, Mann VH, Smircich P, Cogswell AA, Williams DL, Brindley PJ. Vasa-Like DEAD-Box RNA Helicases of Schistosoma mansoni. PLoS Negl Trop Dis 2012; 6:e1686. [PMID: 22720105 PMCID: PMC3373655 DOI: 10.1371/journal.pntd.0001686] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/29/2012] [Indexed: 11/18/2022] Open
Abstract
Genome sequences are available for the human blood flukes, Schistosoma japonicum, S. mansoni and S. haematobium. Functional genomic approaches could aid in identifying the role and importance of these newly described schistosome genes. Transgenesis is established for functional genomics in model species, which can lead to gain- or loss-of-functions, facilitate vector-based RNA interference, and represents an effective forward genetics tool for insertional mutagenesis screens. Progress toward routine transgenesis in schistosomes might be expedited if germ cells could be reliably localized in cultured schistosomes. Vasa, a member of the ATP-dependent DEAD-box RNA helicase family, is a prototypic marker of primordial germ cells and the germ line in the Metazoa. Using bioinformatics, 33 putative DEAD-box RNA helicases exhibiting conserved motifs that characterize helicases of this family were identified in the S. mansoni genome. Moreover, three of the helicases exhibited vasa-like sequences; phylogenetic analysis confirmed the three vasa-like genes-termed Smvlg1, Smvlg2, and Smvlg3-were members of the Vasa/PL10 DEAD-box subfamily. Transcripts encoding Smvlg1, Smvlg2, and Smvlg3 were cloned from cDNAs from mixed sex adult worms, and quantitative real time PCR revealed their presence in developmental stages of S. mansoni with elevated expression in sporocysts, adult females, eggs, and miracidia, with strikingly high expression in the undeveloped egg. Whole mount in situ hybridization (WISH) analysis revealed that Smvlg1, Smvlg2 and Smvlg3 were transcribed in the posterior ovary where the oocytes mature. Germ cell specific expression of schistosome vasa-like genes should provide an informative landmark for germ line transgenesis of schistosomes, etiologic agents of major neglected tropical diseases.
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Affiliation(s)
- Danielle E. Skinner
- Department of Microbiology, Immunology & Tropical Medicine, and Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, George Washington University, Washington, D. C., United States of America
| | - Gabriel Rinaldi
- Department of Microbiology, Immunology & Tropical Medicine, and Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, George Washington University, Washington, D. C., United States of America
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Sutas Suttiprapa
- Department of Pathobiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Victoria H. Mann
- Department of Microbiology, Immunology & Tropical Medicine, and Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, George Washington University, Washington, D. C., United States of America
| | - Pablo Smircich
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Alexis A. Cogswell
- Department of Microbiology and Immunology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - David L. Williams
- Department of Microbiology and Immunology, Rush University Medical Center, Chicago, Illinois, United States of America
| | - Paul J. Brindley
- Department of Microbiology, Immunology & Tropical Medicine, and Center for Neglected Diseases of Poverty, School of Medicine & Health Sciences, George Washington University, Washington, D. C., United States of America
- * E-mail:
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11
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Hagen J, Lee EF, Fairlie WD, Kalinna BH. Functional genomics approaches in parasitic helminths. Parasite Immunol 2012; 34:163-82. [PMID: 21711361 DOI: 10.1111/j.1365-3024.2011.01306.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
As research on parasitic helminths is moving into the post-genomic era, an enormous effort is directed towards deciphering gene function and to achieve gene annotation. The sequences that are available in public databases undoubtedly hold information that can be utilized for new interventions and control but the exploitation of these resources has until recently remained difficult. Only now, with the emergence of methods to genetically manipulate and transform parasitic worms will it be possible to gain a comprehensive understanding of the molecular mechanisms involved in nutrition, metabolism, developmental switches/maturation and interaction with the host immune system. This review focuses on functional genomics approaches in parasitic helminths that are currently used, to highlight potential applications of these technologies in the areas of cell biology, systems biology and immunobiology of parasitic helminths.
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Affiliation(s)
- J Hagen
- Department of Veterinary Science, Centre for Animal Biotechnology, The University of Melbourne, Vic., Australia
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Abstract
PURPOSE OF REVIEW Schistosomiasis is a chronic and morbid disease that affects hundreds of millions of the poorest individuals in (sub)tropical regions, particularly sub-Saharan Africa. Just one drug, praziquantel (PZQ), is available. As discussed, efforts to expand mass drug administration programs may accelerate the emergence of resistance. In addition, PZQ's peculiar pharmacological profile and undefined mechanism of action(s) complicate discriminating incomplete efficacy from true resistance. Accordingly, and in spite of the challenges associated with developing new antischistosomals as discussed herein, alternatives to PZQ should be identified. Various strategies to do this are highlighted here. RECENT FINDINGS The last 2 years have witnessed more engagement of the necessary infrastructure combined with the application of the latest strategies and technologies to facilitate antischistosomal drug discovery. Preclinical and clinical evaluation of new chemistries has benefited from various consortia and institutions that underwrite drug development for antiparasitics in general. Drug repositioning, target-based drug design, improved automation for compound screening, genomics and functional genomics are just some of the tools now being applied to identify possible new drugs and drug targets. SUMMARY The new momentum toward the discovery of alternatives to PZQ is encouraging but needs to be sustained by a stronger advocacy for drug development, in addition to drug deployment.
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Rinaldi G, Suttiprapa S, Tort JF, Folley AE, Skinner DE, Brindley PJ. An antibiotic selection marker for schistosome transgenesis. Int J Parasitol 2011; 42:123-30. [PMID: 22155152 DOI: 10.1016/j.ijpara.2011.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2011] [Revised: 11/16/2011] [Accepted: 11/17/2011] [Indexed: 11/26/2022]
Abstract
Drug selection is widely used in transgene studies of microbial pathogens, mammalian cell and plant cell lines. Drug selection of transgenic schistosomes would be desirable to provide a means to enrich for populations of transgenic worms. We adapted murine leukaemia retrovirus vectors - widely used in human gene therapy research - to transduce schistosomes, leading to integration of transgenes into the genome of the blood fluke. A dose-response kill curve and lethal G418 (geneticin) concentrations were established: 125-1,000μg/ml G418 were progressively more toxic for schistosomules of Schistosoma mansoni with toxicity increasing with antibiotic concentration and with duration of exposure. By day 6 of exposure to ⩾500μg/ml, significantly fewer worms survived compared with non-exposed controls and by day 8, significantly fewer worms survived than controls at ⩾250μg/ml G418. When schistosomules were transduced with murine leukaemia retrovirus encoding the neomycin resistance (neoR) transgene and cultured in media containing G418, the neoR transgene rescued transgenic schistosomules from the antibiotic; by day 4 in 1,000μg/ml and by day 8 in 500μg/ml G418, significantly more transgenic worms survived the toxic effects of the antibiotic. More copies of neoR were detected per nanogram of genomic DNA from populations of transgenic schistosomes cultured in G418 than from transgenic schistosomes cultured without G418. This trend was G418 dose-dependent, demonstrating enrichment of transgenic worms from among the schistosomules exposed to virions. Furthermore, higher expression of neoR was detected in transgenic schistosomes cultured in the presence of G418 than in transgenic worms cultured without antibiotic. The availability of antibiotic selection can be expected to enhance progress with functional genomics research on the helminth parasites responsible for major neglected tropical diseases.
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Affiliation(s)
- Gabriel Rinaldi
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine & Health Sciences, The George Washington University, 2300 I Street NW, Washington, DC 20037, USA
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Rinaldi G, Okatcha TI, Popratiloff A, Ayuk MA, Suttiprapa S, Mann VH, Liang YS, Lewis FA, Loukas A, Brindley PJ. Genetic manipulation of Schistosoma haematobium, the neglected schistosome. PLoS Negl Trop Dis 2011; 5:e1348. [PMID: 22022628 PMCID: PMC3191139 DOI: 10.1371/journal.pntd.0001348] [Citation(s) in RCA: 39] [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: 06/17/2011] [Accepted: 08/22/2011] [Indexed: 11/19/2022] Open
Abstract
Background Minimal information on the genome and proteome of Schistosoma haematobium is available, in marked contrast to the situation with the other major species of human schistosomes for which draft genome sequences have been reported. Accordingly, little is known about functional genomics in S. haematobium, including the utility or not of RNA interference techniques that, if available, promise to guide development of new interventions for schistosomiasis haematobia. Methods/Findings Here we isolated and cultured developmental stages of S. haematobium, derived from experimentally infected hamsters. Targeting different developmental stages, we investigated the utility of soaking and/or square wave electroporation in order to transfect S. haematobium with nucleic acid reporters including Cy3-labeled small RNAs, messenger RNA encoding firefly luciferase, and short interfering RNAs (siRNAs). Three hours after incubation of S. haematobium eggs in 50 ng/µl Cy3-labeled siRNA, fluorescent foci were evident indicating that labeled siRNA had penetrated into miracidia developing within the egg shell. Firefly luciferase activity was detected three hours after square wave electroporation of the schistosome eggs and adult worms in 150 ng/µl of mRNA. RNA interference knockdown (silencing) of reporter luciferase activity was seen following the introduction of dsRNA specific for luciferase mRNA in eggs, schistosomules and mixed sex adults. Moreover, introduction of an endogenous gene-specific siRNA into adult schistosomes silenced transcription of tetraspanin 2 (Sh-tsp-2), the apparent orthologue of the Schistosoma mansoni gene Sm-tsp-2 which encodes the surface localized structural and signaling protein Sm-TSP-2. Together, knockdown of reporter luciferase and Sh-tsp-2 indicated the presence of an intact RNAi pathway in S. haematobium. Also, we employed laser scanning confocal microscopy to view the adult stages of S. haematobium. Conclusions These findings and approaches should facilitate analysis of gene function in S. haematobium, which in turn could facilitate the characterization of prospective intervention targets for this neglected tropical disease pathogen. More people are infected with Schistosoma haematobium than other major human schistosomes yet it has been less studied because of difficulty in maintaining the life cycle in the laboratory. S. haematobium might be considered the ‘neglected schistosome’ since minimal information on the genome and proteome of S. haematobium is available, in marked contrast to the other major schistosomes. In this report we describe tools and protocols to investigate the genome and genetics of this neglected schistosome. We cultured developmental stages of S. haematobium, and investigated the utility of introducing gene probes into the parasites to silence two model genes. One of these, firefly luciferase, was a reporter gene whereas the second was a schistosome gene encoding a surface protein, termed Sh-tsp-2. We observed that both genes could be silenced – a phenomenon known as experimental RNA interference (RNAi). These findings indicated that the genome of S. haematobium will be amenable to genetic manipulation investigations designed to determine the function and importance of genes of this schistosome and to investigate for novel anti-parasite treatments.
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Affiliation(s)
- Gabriel Rinaldi
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Tunika I. Okatcha
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, United States of America
| | - Anastas Popratiloff
- Center for Microscopy and Image Analysis, The George Washington University, Washington, DC, United States of America
| | - Mary A. Ayuk
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
| | - Sutas Suttiprapa
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
| | - Victoria H. Mann
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
| | - Yung-san Liang
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - Fred A. Lewis
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - Alex Loukas
- Queensland Tropical Health Alliance, James Cook University, Cairns, Queensland, Australia
| | - Paul J. Brindley
- Department of Microbiology, Immunology and Tropical Medicine, School of Medicine and Health Sciences, The George Washington University Medical Center, Washington, DC, United States of America
- * E-mail:
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Duvoisin R, Ayuk MA, Rinaldi G, Suttiprapa S, Mann VH, Lee CM, Harris N, Brindley PJ. Human U6 promoter drives stronger shRNA activity than its schistosome orthologue in Schistosoma mansoni and human fibrosarcoma cells. Transgenic Res 2011; 21:511-21. [PMID: 21953124 DOI: 10.1007/s11248-011-9548-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 08/23/2011] [Indexed: 10/17/2022]
Abstract
Blood flukes or schistosomes are the causative agents of human schistosomiasis, one of the major neglected tropical diseases. Draft genome sequences have been reported for schistosomes, but functional genomics tools are needed to investigate the role and essentiality of the newly reported genes. Vector based RNA interference can contribute to functional genomics analysis for schistosomes. Using mRNA encoding reporter firefly luciferase as a model target, we compared the performance of a schistosome and a human promoter from the U6 gene in driving shRNA in human fibrosarcoma cells and in cultured schistosomes. Further, both a retroviral [Murine leukemia virus (MLV)] and plasmid (piggyBac, pXL-Bac II) vector were utilized. The schistosome U6 gene promoter was 270 bp in length, the human U6 gene promoter was 264 bp; they shared 41% identity. Following transduction of both HT1080 fibrosarcoma cells and schistosomules of Schistosoma mansoni with pseudotyped MLV virions, stronger knockdown of luciferase activity was seen with the virions encoding the human U6 promoter driven shRNA than the schistosome U6 promoter. A similar trend was seen after transfection of HT1080 cells and schistosomules with the pXL-Bac-II constructs-stronger knockdown of luciferase activity was seen with constructs encoding the human compared to schistosome U6 promoter. The findings indicate that a human U6 gene promoter drives stronger shRNA activity than its schistosome orthologue, not only in a human cancer cell line but also in larval schistosomes. This RNA polymerase III promoter represents a potentially valuable component for vector based RNA interference studies in schistosomes and related platyhelminth parasites.
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Affiliation(s)
- Raphaël Duvoisin
- Department of Microbiology, Immunology & Tropical Medicine, The George Washington University Medical Center, Ross Hall 448, 2300 I Street NW, Washington, DC 20037, USA
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Prototypic chromatin insulator cHS4 protects retroviral transgene from silencing in Schistosoma mansoni. Transgenic Res 2011; 21:555-66. [PMID: 21918820 DOI: 10.1007/s11248-011-9556-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/31/2011] [Indexed: 02/06/2023]
Abstract
Vesicular stomatitis virus glycoprotein (VSVG) pseudotyped murine leukemia virus (MLV) virions can transduce schistosomes, leading to chromosomal integration of reporter transgenes. To develop VSVG-MLV for functional genomics in schistosomes, the influence of the chicken β-globin cHS4 element, a prototypic chromatin insulator, on transgene expression was examined. Plasmid pLNHX encoding the MLV 5'- and 3'-Long Terminal Repeats flanking the neomycin phosphotransferase gene (neo) was modified to include, within the U3 region of the 3'-LTR, active components of cHS4 insulator, the 250 bp core fused to the 400 bp 3'-region. Cultured larvae of Schistosoma mansoni were transduced with virions from producer cells transfected with control or cHS4-bearing plasmids. Schistosomules transduced with cHS4 virions expressed 2-20 times higher levels of neo than controls, while carrying comparable numbers of integrated proviral transgenes. The findings not only demonstrated that cHS4 was active in schistosomes but also they represent the first report of activity of cHS4 in any Lophotrochozoan species, which has significant implications for evolutionary conservation of heterochromatin regulation. The findings advance prospects for transgenesis in functional genomics of the schistosome genome to discover intervention targets because they provide the means to enhance and extend transgene activity including for vector based RNA interference.
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Abstract
SUMMARYIn parasitological research, significant progress has been made with respect to genomics and transcriptomics but transgenic systems for functional gene analyses are mainly restricted to the protozoan field. Gene insertion and knockout strategies can be applied to parasitic protozoa as well as gene silencing by RNA interference (RNAi). By contrast, research on parasitic helminthes still lags behind. Along with the major advances in genome and transcriptome analyses e.g. for schistosomes, methods for the functional characterization of genes of interest are still in their initial phase and have to be elaborated now, at the beginning of the post-genomic era. In this review we will summarize attempts made in the last decade regarding the establishment of protocols to transiently and stably transform or transfect schistosomes. Besides approaches using particle bombardment, electroporation or virus-based infection strateies to introduce DNA constructs into adult and larval schistosome stages to express reporter genes, first approaches have also been made in establishing protocols based on soaking, lipofection, and/or electroporation for RNA interference to silence gene activity. Although in these cases remarkable progress can be seen, the schistosome community eagerly awaits major breakthroughs especially with respect to stable transformation, but also for silencing or knock-down strategies for every schistosome gene of interest.
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Affiliation(s)
- Victoria H. Mann
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, D.C., United States of America
| | - Sutas Suttiprapa
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, D.C., United States of America
| | - Gabriel Rinaldi
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, D.C., United States of America
- Departamento de Genética, Facultad de Medicina, Universidad de la República, (UDELAR), Montevideo, Uruguay
| | - Paul J. Brindley
- Department of Microbiology, Immunology & Tropical Medicine, George Washington University Medical Center, Washington, D.C., United States of America
- * E-mail:
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Abstract
Draft genome sequences for Schistosoma japonicum and S. mansoni are now available. The schistosome genome encodes ∼13,000 protein-encoding genes for which the functions of few are well understood. Nonetheless, the new genes represent potential intervention targets, and molecular tools are being developed to determine their importance. Over the past 15 years, noteworthy progress has been achieved towards development of tools for gene manipulation and transgenesis of schistosomes. A brief history of genetic manipulation is presented, along with a review of the field with emphasis on reports of integration of transgenes into schistosome chromosomes.
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