1
|
Kalinna BH, Ross AG, Walduck AK. Schistosome Transgenesis: The Long Road to Success. BIOLOGY 2024; 13:48. [PMID: 38248478 PMCID: PMC10813141 DOI: 10.3390/biology13010048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/04/2024] [Accepted: 01/11/2024] [Indexed: 01/23/2024]
Abstract
As research on parasitic helminths has entered the post-genomic era, research efforts have turned to deciphering the function of genes in the public databases of genome sequences. It is hoped that, by understanding the role of parasite genes in maintaining their parasitic lifestyle, critical insights can be gained to develop new intervention and control strategies. Methods to manipulate and transform parasitic worms are now developed to a point where it has become possible to gain a comprehensive understanding of the molecular mechanisms underlying host-parasite interplay, and here, we summarise and discuss the advances that have been made in schistosome transgenesis over the past 25 years. The ability to genetically manipulate schistosomes holds promise in finding new ways to control schistosomiasis, which ultimately may lead to the eradication of this debilitating disease.
Collapse
Affiliation(s)
- Bernd H. Kalinna
- Rural Health Research Institute, Charles Sturt University, Orange, NSW 2800, Australia; (A.G.R.); (A.K.W.)
| | | | | |
Collapse
|
2
|
Kukhtar D, Fussenegger M. Synthetic biology in multicellular organisms: Opportunities in nematodes. Biotechnol Bioeng 2023. [PMID: 37448225 DOI: 10.1002/bit.28497] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/27/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023]
Abstract
Synthetic biology has mainly focused on introducing new or altered functionality in single cell systems: primarily bacteria, yeast, or mammalian cells. Here, we describe the extension of synthetic biology to nematodes, in particular the well-studied model organism Caenorhabditis elegans, as a convenient platform for developing applications in a multicellular setting. We review transgenesis techniques for nematodes, as well as the application of synthetic biology principles to construct nematode gene switches and genetic devices to control motility. Finally, we discuss potential applications of engineered nematodes.
Collapse
Affiliation(s)
- Dmytro Kukhtar
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zürich, Basel, Switzerland
- Faculty of Life Science, University of Basel, Basel, Switzerland
| |
Collapse
|
3
|
Nanotechnology for DNA and RNA delivery. Nanomedicine (Lond) 2023. [DOI: 10.1016/b978-0-12-818627-5.00008-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/19/2023] Open
|
4
|
Thekke-Veetil T, McCoppin NK, Domier LL, Hajimorad M, Lambert KN, Lim HS, Hartman GL. Transient expression of a luciferase mRNA in plant-parasitic and free-living nematodes by electroporation. Mol Biochem Parasitol 2022; 250:111489. [DOI: 10.1016/j.molbiopara.2022.111489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/03/2022] [Accepted: 05/25/2022] [Indexed: 11/25/2022]
|
5
|
Quinzo MJ, Perteguer MJ, Brindley PJ, Loukas A, Sotillo J. Transgenesis in parasitic helminths: a brief history and prospects for the future. Parasit Vectors 2022; 15:110. [PMID: 35346328 PMCID: PMC8962113 DOI: 10.1186/s13071-022-05211-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/18/2022] [Indexed: 12/15/2022] Open
Abstract
Helminth infections impact the health of hundreds of millions of persons globally and also cause important economic losses in livestock farming. Methodological limitations as well as the low attention given to the study of helminths have impacted biological research and, thus, the procurement of accurate diagnosis and effective treatments. Understanding the biology of helminths using genomic and proteomic approaches could contribute to advances in understanding host-helminth interactions and lead to new vaccines, drugs and diagnostics. Despite the significant advances in genomics in the last decade, the lack of methodological adaptation of current transgenesis techniques has hampered the progression of post-genomic research in helminthology. However, the application of new techniques, such as CRISPR, to the study of trematodes and nematodes has opened new avenues for genome editing-powered functional genomics for these pathogens. This review summarises the historical advances in functional genomics in parasitic helminths and highlights pending limitations that will need to be overcome to deploy transgenesis tools.
Collapse
Affiliation(s)
- M J Quinzo
- Parasitology Reference and Research Laboratory, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
- Escuela Internacional de Doctorado, Universidad Nacional de Educación a Distancia (UNED), Madrid, Spain
| | - M J Perteguer
- Parasitology Reference and Research Laboratory, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | - P J Brindley
- Department of Microbiology, Immunology and Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington, DC, 20037, USA
| | - A Loukas
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia
| | - J Sotillo
- Parasitology Reference and Research Laboratory, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
| |
Collapse
|
6
|
Imai R, Hamada H, Liu Y, Linghu Q, Kumagai Y, Nagira Y, Miki R, Taoka N. In planta particle bombardment (iPB): A new method for plant transformation and genome editing. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2020; 37:171-176. [PMID: 32821224 PMCID: PMC7434670 DOI: 10.5511/plantbiotechnology.20.0206a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Transformation is a key step in modern breeding technology that involves genome editing. The requirement for in vitro tissue culture and regeneration hampers application of this technology to commercially important varieties of many crop species. To overcome this problem, we developed a simple and reproducible in planta transformation method in wheat (Tritticum aestivum L.). Our in planta particle bombardment (iPB) method utilizes the shoot apical meristem (SAM) as a target tissue. The SAM contains a subepidermal cell layer termed L2, from which germ cells later develop during floral organogenesis. The iPB method can also be used for genome editing through transient CRISPR/Cas9 expression or direct delivery of the CRISPR/Cas9 ribonucleoprotein. In this review, we describe the iPB technology and provide an overview of its current and future applications in plant transformation and genome editing.
Collapse
Affiliation(s)
- Ryozo Imai
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tukuba, Ibaraki 305-8634, Japan
- E-mail: Tel & Fax: +81-29-838-8378
| | - Haruyasu Hamada
- Pharma & Supplemental Nutrition Solutions Vehicle, Biotechnology Research Laboratories, KANEKA CORPORATION, Takasago, Hyogo 676-8688, Japan
| | - Yuelin Liu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tukuba, Ibaraki 305-8634, Japan
| | - Qianyan Linghu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tukuba, Ibaraki 305-8634, Japan
| | - Yuya Kumagai
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization (NARO), 1-2 Owashi, Tukuba, Ibaraki 305-8634, Japan
| | - Yozo Nagira
- Pharma & Supplemental Nutrition Solutions Vehicle, Biotechnology Research Laboratories, KANEKA CORPORATION, Takasago, Hyogo 676-8688, Japan
| | - Ryuji Miki
- Pharma & Supplemental Nutrition Solutions Vehicle, Biotechnology Research Laboratories, KANEKA CORPORATION, Takasago, Hyogo 676-8688, Japan
| | - Naoaki Taoka
- Pharma & Supplemental Nutrition Solutions Vehicle, Biotechnology Research Laboratories, KANEKA CORPORATION, Takasago, Hyogo 676-8688, Japan
| |
Collapse
|
7
|
Novobilský A, Höglund J. Small animal in vivo imaging of parasitic infections: A systematic review. Exp Parasitol 2020; 214:107905. [PMID: 32387050 DOI: 10.1016/j.exppara.2020.107905] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Revised: 04/27/2020] [Accepted: 05/01/2020] [Indexed: 10/24/2022]
Abstract
Non-invasive small animal in vivo imaging is an essential tool in a broad variety of biomedical sciences and enables continuous monitoring of disease progression in order to develop and improve diagnostic, therapeutic and preventive measures. Imaging parasites non-invasively in live animals allows efficient parasite distribution evaluation in the host organism and objective evaluation of parasitic diseases' burden and progression in individual animals. The aim of this systematic review was to summarize recent trends in small animal in vivo imaging and compare and discuss imaging of single-cell and multicellular eukaryotic parasites. A literature survey was performed using Web of Science and PubMed databases in research articles published between 1990 and 2018. The inclusion criteria were using any imaging method to visualize a range of protozoan and helminth parasites in laboratory animals in vivo. A total of 92 studies met our inclusion criteria. Protozoans and helminths were imaged in 88% and 12% of 92 studies, respectively. The most common parasite genus studied was the protozoan Plasmodium followed by Trypanosoma and Leishmania. The most frequent imaging method was bioluminescence. Among the helminths, Schistosoma and Echinococcus were the most studied organisms. In vivo imaging is applicable in both protozoans and helminths. In helminths, however, the use of in vivo imaging methods is limited to some extent. Imaging parasites in small animal models is a powerful tool in preclinical research aiming to develop novel therapeutic and preventive strategies for parasitic diseases of interest both in human and veterinary medicine.
Collapse
Affiliation(s)
- Adam Novobilský
- Veterinary Research Institute, Department of Pharmacology and Immunotherapy, Hudcova 70, 62100, Brno, Czech Republic.
| | - Johan Höglund
- Swedish University of Agricultural Sciences, Department of Biological Sciences and Veterinary Public Health, Section for Parasitology, Box 7036, 750 07, Uppsala, Sweden
| |
Collapse
|
8
|
Castelletto ML, Gang SS, Hallem EA. Recent advances in functional genomics for parasitic nematodes of mammals. ACTA ACUST UNITED AC 2020; 223:223/Suppl_1/jeb206482. [PMID: 32034038 DOI: 10.1242/jeb.206482] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Human-parasitic nematodes infect over a quarter of the world's population and are a major cause of morbidity in low-resource settings. Currently available treatments have not been sufficient to eliminate infections in endemic areas, and drug resistance is an increasing concern, making new treatment options a priority. The development of new treatments requires an improved understanding of the basic biology of these nematodes. Specifically, a better understanding of parasitic nematode development, reproduction and behavior may yield novel drug targets or new opportunities for intervention such as repellents or traps. Until recently, our ability to study parasitic nematode biology was limited because few tools were available for their genetic manipulation. This is now changing as a result of recent advances in the large-scale sequencing of nematode genomes and the development of new techniques for their genetic manipulation. Notably, skin-penetrating gastrointestinal nematodes in the genus Strongyloides are now amenable to transgenesis, RNAi and CRISPR/Cas9-mediated targeted mutagenesis, positioning the Strongyloides species as model parasitic nematode systems. A number of other mammalian-parasitic nematodes, including the giant roundworm Ascaris suum and the tissue-dwelling filarial nematode Brugia malayi, are also now amenable to transgenesis and/or RNAi in some contexts. Using these tools, recent studies of Strongyloides species have already provided insight into the molecular pathways that control the developmental decision to form infective larvae and that drive the host-seeking behaviors of infective larvae. Ultimately, a mechanistic understanding of these processes could lead to the development of new avenues for nematode control.
Collapse
Affiliation(s)
- Michelle L Castelletto
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Spencer S Gang
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92161, USA
| | - Elissa A Hallem
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| |
Collapse
|
9
|
Lok JB. CRISPR/Cas9 Mutagenesis and Expression of Dominant Mutant Transgenes as Functional Genomic Approaches in Parasitic Nematodes. Front Genet 2019; 10:656. [PMID: 31379923 PMCID: PMC6646703 DOI: 10.3389/fgene.2019.00656] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 06/21/2019] [Indexed: 12/13/2022] Open
Abstract
DNA transformation of parasitic nematodes enables novel approaches to validating predictions from genomic and transcriptomic studies of these important pathogens. Notably, proof of principle for CRISPR/Cas9 mutagenesis has been achieved in Strongyloides spp., allowing identification of molecules essential to the functions of sensory neurons that mediate behaviors comprising host finding, invasion, and location of predilection sites by parasitic nematodes. Likewise, CRISPR/Cas9 knockout of the developmental regulatory transcription factor Ss-daf-16 has validated its function in regulating morphogenesis of infective third-stage larvae in Strongyloides stercoralis. While encouraging, these studies underscore challenges that remain in achieving straightforward validation of essential intervention targets in parasitic nematodes. Chief among these is the likelihood that knockout of multifunctional regulators like Ss-DAF-16 or its downstream mediator, the nuclear receptor Ss-DAF-12, will produce phenotypes so complex as to defy interpretation and will render affected worms incapable of infecting their hosts, thus preventing establishment of stable mutant lines. Approaches to overcoming these impediments could involve refinements to current CRISPR/Cas9 methods in Strongyloides including regulatable Cas9 expression from integrated transgenes and CRISPR/Cas9 editing to ablate specific functional motifs in regulatory molecules without complete knockout. Another approach would express transgenes encoding regulatory molecules of interest with mutations designed to similarly ablate or degrade specific functional motifs such as the ligand binding domain of Ss-DAF-12 while preserving core functions such as DNA binding. Such mutant transgenes would be expected to exert a dominant interfering effect on their endogenous counterparts. Published reports validate the utility of such dominant-negative approaches in Strongyloides.
Collapse
Affiliation(s)
- James B Lok
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
10
|
Stewart MP, Langer R, Jensen KF. Intracellular Delivery by Membrane Disruption: Mechanisms, Strategies, and Concepts. Chem Rev 2018; 118:7409-7531. [PMID: 30052023 PMCID: PMC6763210 DOI: 10.1021/acs.chemrev.7b00678] [Citation(s) in RCA: 406] [Impact Index Per Article: 67.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Intracellular delivery is a key step in biological research and has enabled decades of biomedical discoveries. It is also becoming increasingly important in industrial and medical applications ranging from biomanufacture to cell-based therapies. Here, we review techniques for membrane disruption-based intracellular delivery from 1911 until the present. These methods achieve rapid, direct, and universal delivery of almost any cargo molecule or material that can be dispersed in solution. We start by covering the motivations for intracellular delivery and the challenges associated with the different cargo types-small molecules, proteins/peptides, nucleic acids, synthetic nanomaterials, and large cargo. The review then presents a broad comparison of delivery strategies followed by an analysis of membrane disruption mechanisms and the biology of the cell response. We cover mechanical, electrical, thermal, optical, and chemical strategies of membrane disruption with a particular emphasis on their applications and challenges to implementation. Throughout, we highlight specific mechanisms of membrane disruption and suggest areas in need of further experimentation. We hope the concepts discussed in our review inspire scientists and engineers with further ideas to improve intracellular delivery.
Collapse
Affiliation(s)
- Martin P. Stewart
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Robert Langer
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
- The Koch Institute for Integrative Cancer Research,
Massachusetts Institute of Technology, Cambridge, USA
| | - Klavs F. Jensen
- Department of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, USA
| |
Collapse
|
11
|
Namai S, Sugimoto A. Transgenesis by microparticle bombardment for live imaging of fluorescent proteins in Pristionchus pacificus germline and early embryos. Dev Genes Evol 2018; 228:75-82. [DOI: 10.1007/s00427-018-0605-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/09/2018] [Indexed: 01/26/2023]
|
12
|
Lok JB, Shao H, Massey HC, Li X. Transgenesis in Strongyloides and related parasitic nematodes: historical perspectives, current functional genomic applications and progress towards gene disruption and editing. Parasitology 2017; 144:327-342. [PMID: 27000743 PMCID: PMC5364836 DOI: 10.1017/s0031182016000391] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 02/10/2016] [Accepted: 02/10/2016] [Indexed: 12/20/2022]
Abstract
Transgenesis for Strongyloides and Parastrongyloides was accomplished in 2006 and is based on techniques derived for Caenorhabditis elegans over two decades earlier. Adaptation of these techniques has been possible because Strongyloides and related parasite genera carry out at least one generation of free-living development, with adult males and females residing in soil contaminated by feces from an infected host. Transgenesis in this group of parasites is accomplished by microinjecting DNA constructs into the syncytia of the distal gonads of free-living females. In Strongyloides stercoralis, plasmid-encoded transgenes are expressed in promoter-regulated fashion in the F1 generation following gene transfer but are silenced subsequently. Stable inheritance and expression of transgenes in S. stercoralis requires their integration into the genome, and stable lines have been derived from integrants created using the piggyBac transposon system. More direct investigations of gene function involving expression of mutant transgene constructs designed to alter intracellular trafficking and developmental regulation have shed light on the function of the insulin-regulated transcription factor Ss-DAF-16. Transgenesis in Strongyloides and Parastrongyloides opens the possibility of powerful new methods for genome editing and transcriptional manipulation in this group of parasites. Proof of principle for one of these, CRISPR/Cas9, is presented in this review.
Collapse
Affiliation(s)
- J B Lok
- Department of Pathobiology,School of Veterinary Medicine,University of Pennsylvania,3800 Spruce Street,Philadelphia,PA 19104,USA
| | - H Shao
- Department of Pathobiology,School of Veterinary Medicine,University of Pennsylvania,3800 Spruce Street,Philadelphia,PA 19104,USA
| | - H C Massey
- Department of Pathobiology,School of Veterinary Medicine,University of Pennsylvania,3800 Spruce Street,Philadelphia,PA 19104,USA
| | - X Li
- Department of Pathobiology,School of Veterinary Medicine,University of Pennsylvania,3800 Spruce Street,Philadelphia,PA 19104,USA
| |
Collapse
|
13
|
The NIH-NIAID Schistosomiasis Resource Center at the Biomedical Research Institute: Molecular Redux. PLoS Negl Trop Dis 2016; 10:e0005022. [PMID: 27764112 PMCID: PMC5072641 DOI: 10.1371/journal.pntd.0005022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Schistosomiasis remains a health burden in many parts of the world. The complex life cycle of Schistosoma parasites and the economic and societal conditions present in endemic areas make the prospect of eradication unlikely in the foreseeable future. Continued and vigorous research efforts must therefore be directed at this disease, particularly since only a single World Health Organization (WHO)-approved drug is available for treatment. The National Institutes of Health (NIH)–National Institute of Allergy and Infectious Diseases (NIAID) Schistosomiasis Resource Center (SRC) at the Biomedical Research Institute provides investigators with the critical raw materials needed to carry out this important research. The SRC makes available, free of charge (including international shipping costs), not only infected host organisms but also a wide array of molecular reagents derived from all life stages of each of the three main human schistosome parasites. As the field of schistosomiasis research rapidly advances, it is likely to become increasingly reliant on omics, transgenics, epigenetics, and microbiome-related research approaches. The SRC has and will continue to monitor and contribute to advances in the field in order to support these research efforts with an expanding array of molecular reagents. In addition to providing investigators with source materials, the SRC has expanded its educational mission by offering a molecular techniques training course and has recently organized an international schistosomiasis-focused meeting. This review provides an overview of the materials and services that are available at the SRC for schistosomiasis researchers, with a focus on updates that have occurred since the original overview in 2008.
Collapse
|
14
|
Britton C, Roberts B, Marks ND. Functional Genomics Tools for Haemonchus contortus and Lessons From Other Helminths. ADVANCES IN PARASITOLOGY 2016; 93:599-623. [PMID: 27238014 DOI: 10.1016/bs.apar.2016.02.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The availability of genome and transcriptome data for parasitic nematodes, including Haemonchus contortus, has highlighted the need to develop functional genomics tools. Comparative genomic analysis, particularly using data from the free-living nematode Caenorhabditis elegans, can help predict gene function. Reliable approaches to study function directly in parasitic nematodes are currently lacking. However, gene knockdown by RNA interference (RNAi) is being successfully used in schistosome and planarian species to define gene functions. Lessons from these systems may be applied to improve RNAi in H. contortus. Previous studies in H. contortus and related nematodes demonstrated reliable RNAi-mediated silencing of some genes, but not others. Current data suggest that susceptibility to RNAi in these nematodes is limited to genes expressed in sites accessible to the environment, such as the gut, amphids and excretory cell. Therefore, RNAi is functional in H. contortus, but improvements are needed to develop this system as a functional genomics platform. Here, we summarize RNAi studies on H. contortus and discuss the optimization of RNA delivery and improvements to culture methods to enhance larval development, protein turnover and the induction of phenotypic effects in vitro. The transgenic delivery of RNA or dominant-negative gene constructs and the recently developed CRISPR/Cas genome-editing technique are considered as potential alternative approaches for gene knockout. This is a key time to devote greater effort in progressing from genome to function, to improve our understanding of the biology of Haemonchus and identify novel targets for parasite control.
Collapse
Affiliation(s)
- C Britton
- University of Glasgow, Glasgow, United Kingdom
| | - B Roberts
- University of Glasgow, Glasgow, United Kingdom
| | - N D Marks
- University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
15
|
Ward JD. Rendering the Intractable More Tractable: Tools from Caenorhabditis elegans Ripe for Import into Parasitic Nematodes. Genetics 2015; 201:1279-94. [PMID: 26644478 PMCID: PMC4676526 DOI: 10.1534/genetics.115.182717] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 10/20/2015] [Indexed: 12/14/2022] Open
Abstract
Recent and rapid advances in genetic and molecular tools have brought spectacular tractability to Caenorhabditis elegans, a model that was initially prized because of its simple design and ease of imaging. C. elegans has long been a powerful model in biomedical research, and tools such as RNAi and the CRISPR/Cas9 system allow facile knockdown of genes and genome editing, respectively. These developments have created an additional opportunity to tackle one of the most debilitating burdens on global health and food security: parasitic nematodes. I review how development of nonparasitic nematodes as genetic models informs efforts to import tools into parasitic nematodes. Current tools in three commonly studied parasites (Strongyloides spp., Brugia malayi, and Ascaris suum) are described, as are tools from C. elegans that are ripe for adaptation and the benefits and barriers to doing so. These tools will enable dissection of a huge array of questions that have been all but completely impenetrable to date, allowing investigation into host-parasite and parasite-vector interactions, and the genetic basis of parasitism.
Collapse
Affiliation(s)
- Jordan D Ward
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158
| |
Collapse
|
16
|
Moguel B, Moreno-Mendoza N, Bobes RJ, Carrero JC, Chimal-Monroy J, Díaz-Hernández ME, Herrera-Estrella L, Laclette JP. Transient transgenesis of the tapeworm Taenia crassiceps. SPRINGERPLUS 2015; 4:496. [PMID: 26389021 PMCID: PMC4571025 DOI: 10.1186/s40064-015-1278-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 08/26/2015] [Indexed: 11/10/2022]
Abstract
Human and porcine cysticercosis is caused by the larval stage of the flatworm Taenia solium (Cestoda). Infestation of the human brain, also known as neurocysticercosis, is the most common parasite disease of the central nervous system worldwide. Significant advances in the understanding of the disease have been achieved using the Taenia crassiceps murine model. We describe here a successful transfection protocol of T. crassiceps cysticerci as the first step to approach a number of currently inaccessible biological questions on cysticercosis. T. crassiceps cysticerci (ORF strain) were microinjected with the plasmid pcDNA3.1/NT-GFP-TOPO, encoding the green fluorescent protein (GFP) driven by a cytomegalovirus promoter (CMV). Twelve hours after the microinjection, GFP fluorescence gradually developed in patches associated to bud structures in the bladder wall of cysts. Fluorescence reached a peak at 24-48 h and lasted up to 72 h after the microinjection. Immunohistochemical studies on tissue sections of transfected cysts using an anti-GFP antibody, demonstrated co-localization of the antibody and the GFP fluorescence in the tegumentary cytoplasm and subtegumentary cytons. To validate at the mRNA level the expression of GFP, we carried out RT-PCR using two pairs of nested primers. Results showed expression of GFP-mRNA at 24 h post-transfection. Moreover, western blot assays of crude extracts of transfected cysts, carried out using the anti-GFP specific antibody, showed the expected protein band of 27 kDa, demonstrating that the GFP expression started at 24 after plasmid microinjection and was maintained up to 72 h. These findings will facilitate the development of functional genomics approaches applied to this model of cysticercosis.
Collapse
Affiliation(s)
- Bárbara Moguel
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Norma Moreno-Mendoza
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Raúl J Bobes
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Julio C Carrero
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Jesús Chimal-Monroy
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Martha E Díaz-Hernández
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| | - Luis Herrera-Estrella
- National Laboratory of Genomics for Biodiversity-cinvestav, Km 9.6 Libramiento Norte Carretera Irapuato-León, C.P. 36821 Irapuato, Gto México
| | - Juan P Laclette
- Institute for Biomedical Research, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán, C.P. 04510 México DF, México
| |
Collapse
|
17
|
Transfection of Platyhelminthes. BIOMED RESEARCH INTERNATIONAL 2015; 2015:206161. [PMID: 26090388 PMCID: PMC4450235 DOI: 10.1155/2015/206161] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/09/2014] [Accepted: 09/15/2014] [Indexed: 01/22/2023]
Abstract
Flatworms are one of the most diverse groups within Lophotrochozoa with more than 20,000 known species, distributed worldwide in different ecosystems, from the free-living organisms in the seas and lakes to highly specialized parasites living in a variety of hosts, including humans. Several infections caused by flatworms are considered major neglected diseases affecting countries in the Americas, Asia, and Africa. For several decades, a particular interest on free-living flatworms was due to their ability to regenerate considerable portions of the body, implying the presence of germ cells that could be important for medicine. The relevance of reverse genetics for this group is clear; understanding the phenotypic characteristics of specific genes will shed light on developmental traits of free-living and parasite worms. The genetic manipulation of flatworms will allow learning more about the mechanisms for tissue regeneration, designing new and more effective anthelmintic drugs, and explaining the host-parasite molecular crosstalk so far partially inaccessible for experimentation. In this review, availability of transfection techniques is analyzed across flatworms, from the initial transient achievements to the stable manipulations now developed for free-living and parasite species.
Collapse
|
18
|
Knocking down schistosomes - promise for lentiviral transduction in parasites. Trends Parasitol 2015; 31:324-32. [PMID: 25933926 DOI: 10.1016/j.pt.2015.03.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 12/21/2022]
Abstract
Underpinned by major advances in our understanding of the genomes of schistosomes, progress in the development of functional genomic tools is providing unique prospects to gain insights into the intricacies of the biology of these blood flukes, their host relationships, and the diseases that they cause. This article reviews some key applications of double-stranded RNA interference (RNAi) in Schistosoma mansoni, appraises delivery systems for transgenesis and stable gene silencing, considers ways of increasing efficiency and specificity of gene silencing, and discusses the prospects of using a lentivirus delivery system for future functional genomic-phenomic explorations of schistosomes and other parasites. The ability to achieve effective and stable gene perturbation in parasites has major biological implications and could facilitate the development of new interventions.
Collapse
|
19
|
Martin-Ortigosa S, Wang K. Proteolistics: a biolistic method for intracellular delivery of proteins. Transgenic Res 2014; 23:743-56. [PMID: 25092532 DOI: 10.1007/s11248-014-9807-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 05/29/2014] [Indexed: 11/26/2022]
Abstract
In this work, an intracellular protein delivery methodology termed "proteolistics" is described. This method utilizes a biolistic gun apparatus and involves a simple protein/projectile preparation step. The protein to be delivered is mixed with a gold particle microprojectile suspension and is placed onto a gene gun cartridge, where it is dehydrated using either lyophilization or room-temperature air-drying. Subsequent intracellular protein delivery is achieved in plant and mammalian tissues upon bombardment. Because the method does not require modification of delivery agents or cargo biomolecules and involves a simple physical deposition of the protein onto the microprojectiles, there is no restriction on protein type in terms of molecular weight, isoelectric point or tertiary structure. Because the method delivers protein through the widely used gene gun system, it can be readily applied to any tissue or organism amenable to biolistics. A variety of proteins with molecular weight ranging from 24 to 68 kDa and isoelectric point from 4.8 to 10.1 were tested in this work. It is anticipated that this simple and versatile technique will offer biologists a powerful tool for basic research in areas such as understanding of cell and gene functions and for biotechnological applications such as genome editing.
Collapse
Affiliation(s)
- Susana Martin-Ortigosa
- Center for Plant Transformation, Plant Sciences Institute and Department of Agronomy, Iowa State University, Ames, IA, 50011, USA,
| | | |
Collapse
|
20
|
Rinaldi G, Young ND, Honeycutt JD, Brindley PJ, Gasser RB, Hsieh MH. New research tools for urogenital schistosomiasis. J Infect Dis 2014; 211:861-9. [PMID: 25240172 DOI: 10.1093/infdis/jiu527] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Approximately 200,000,000 people have schistosomiasis (schistosome infection). Among the schistosomes, Schistosoma haematobium is responsible for the most infections, which are present in 110 million people globally, mostly in sub-Saharan Africa. This pathogen causes an astonishing breadth of sequelae: hematuria, anemia, dysuria, stunting, uremia, bladder cancer, urosepsis, and human immunodeficiency virus coinfection. Refined estimates of the impact of schistosomiasis on quality of life suggest that it rivals malaria. Despite S. haematobium's importance, relevant research has lagged. Here, we review advances that will deepen knowledge of S. haematobium. Three sets of breakthroughs will accelerate discoveries in the pathogenesis of urogenital schistosomiasis (UGS): (1) comparative genomics, (2) the development of functional genomic tools, and (3) the use of animal models to explore S. haematobium-host interactions. Comparative genomics for S. haematobium is feasible, given the sequencing of multiple schistosome genomes. Features of the S. haematobium genome that are conserved among platyhelminth species and others that are unique to S. haematobium may provide novel diagnostic and drug targets for UGS. Although there are technical hurdles, the integrated use of these approaches can elucidate host-pathogen interactions during this infection and can inform the development of techniques for investigating schistosomes in their human and snail hosts and the development of therapeutics and vaccines for the control of UGS.
Collapse
Affiliation(s)
- Gabriel Rinaldi
- Department of Microbiology, Immunology, and Tropical Medicine Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington, D.C
| | - Neil D Young
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia
| | | | - Paul J Brindley
- Department of Microbiology, Immunology, and Tropical Medicine Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University, Washington, D.C
| | - Robin B Gasser
- Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Australia Institute of Parasitology and Tropical Veterinary Medicine, Berlin, Germany
| | - Michael H Hsieh
- Biomedical Research Institute, Rockville, Maryland Children's National Health System, Washington, D.C
| |
Collapse
|
21
|
Liang S, Varrecchia M, Ishida K, Jolly ER. Evaluation of schistosome promoter expression for transgenesis and genetic analysis. PLoS One 2014; 9:e98302. [PMID: 24858918 PMCID: PMC4032330 DOI: 10.1371/journal.pone.0098302] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 04/30/2014] [Indexed: 01/23/2023] Open
Abstract
Schistosome worms of the genus Schistosoma are the causative agents of schistosomiasis, a devastating parasitic disease affecting more than 240 million people worldwide. Schistosomes have complex life cycles, and have been challenging to manipulate genetically due to the dearth of molecular tools. Although the use of gene overexpression, gene knockouts or knockdowns are straight-forward genetic tools applied in many model systems, gene misexpression and genetic manipulation of schistosome genes in vivo has been exceptionally challenging, and plasmid based transfection inducing gene expression is limited. We recently reported the use of polyethyleneimine (PEI) as a simple and effective method for schistosome transfection and gene expression. Here, we use PEI-mediated schistosome plasmid transgenesis to define and compare gene expression profiles from endogenous and nonendogenous promoters in the schistosomula stage of schistosomes that are potentially useful to misexpress (underexpress or overexpress) gene product levels. In addition, we overexpress schistosome genes in vivo using a strong promoter and show plasmid-based misregulation of genes in schistosomes, producing a clear and distinct phenotype--death. These data focus on the schistosomula stage, but they foreshadow strong potential for genetic characterization of schistosome molecular pathways, and potential for use in overexpression screens and drug resistance studies in schistosomes using plasmid-based gene expression.
Collapse
Affiliation(s)
- Shuang Liang
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Melissa Varrecchia
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kenji Ishida
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Emmitt R. Jolly
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| |
Collapse
|
22
|
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]
|
23
|
Ye Q, Dong HF, Grevelding CG, Hu M. In vitro cultivation of Schistosoma japonicum-parasites and cells. Biotechnol Adv 2013; 31:1722-37. [DOI: 10.1016/j.biotechadv.2013.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 09/06/2013] [Accepted: 09/08/2013] [Indexed: 11/27/2022]
|
24
|
Pearce EJ, Lok JB. Imaging trematode and nematode parasites. Parasite Immunol 2013; 35:248-55. [DOI: 10.1111/pim.12051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/03/2013] [Indexed: 11/27/2022]
Affiliation(s)
- E. J. Pearce
- Division of Immunobiology; Department of Pathology and Immunology; Washington University School of Medicine; St. Louis; MO; USA
| | - J. B. Lok
- Department of Pathobiology; University of Pennsylvania School of Veterinary Medicine; Philadelphia; PA; USA
| |
Collapse
|
25
|
Liang S, Knight M, Jolly ER. Polyethyleneimine mediated DNA transfection in schistosome parasites and regulation of the WNT signaling pathway by a dominant-negative SmMef2. PLoS Negl Trop Dis 2013; 7:e2332. [PMID: 23936566 PMCID: PMC3723562 DOI: 10.1371/journal.pntd.0002332] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 06/14/2013] [Indexed: 01/17/2023] Open
Abstract
Schistosomiasis is a serious global problem and the second most devastating parasitic disease following malaria. Parasitic worms of the genus Schistosoma are the causative agents of schistosomiasis and infect more than 240 million people worldwide. The paucity of molecular tools to manipulate schistosome gene expression has made an understanding of genetic pathways in these parasites difficult, increasing the challenge of identifying new potential drugs for treatment. Here, we describe the use of a formulation of polyethyleneimine (PEI) as an alternative to electroporation for the efficacious transfection of genetic material into schistosome parasites. We show efficient expression of genes from a heterologous CMV promoter and from the schistosome Sm23 promoter. Using the schistosome myocyte enhancer factor 2 (SmMef2), a transcriptional activator critical for myogenesis and other developmental pathways, we describe the development of a dominant-negative form of the schistosome Mef2. Using this mutant, we provide evidence that SmMef2 may regulate genes in the WNT pathway. We also show that SmMef2 regulates its own expression levels. These data demonstrate the use of PEI to facilitate effective transfection of nucleic acids into schistosomes, aiding in the study of schistosome gene expression and regulation, and development of genetic tools for the characterization of molecular pathways in these parasites.
Collapse
Affiliation(s)
- Shuang Liang
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Matty Knight
- Biomedical Research Institute, Rockville, Maryland, United States of America
| | - Emmitt R. Jolly
- Department of Biology, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
| |
Collapse
|
26
|
Higazi TB, Unnasch TR. Biolistic transformation of Brugia malayi. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2013; 940:103-15. [PMID: 23104337 DOI: 10.1007/978-1-62703-110-3_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
Biolistics has become a versatile tool for direct gene transfer to various cell and tissue types. Following its successful use on the parasitic nematode Ascaris suum, we developed and evaluated biolistics in the transfection of the model filarial parasite Brugia malayi. Biolistics was proven to be an efficient strategy for transfection of all life stages of the parasite and paved the way for studies on elements essential for promoter function and gene regulation of filarial parasites. Here we present a biolistics protocol for the transfection of B. malayi based on the Biolistics PDS 1000/He system and gold microcarriers.
Collapse
Affiliation(s)
- Tarig B Higazi
- Department of Biological Science, Ohio University, Zanesville, OH, USA.
| | | |
Collapse
|
27
|
Li J, Zou J, Yin G, Liu X, Suo X. Plasmid DNA could be delivered into Eimeria maxima unsporulated oocyst with gene gun system. Acta Vet Hung 2012; 60:431-40. [PMID: 23160025 DOI: 10.1556/avet.2012.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Eimerian coccidia are the most common parasitic organisms infecting chickens. The feasibility of genetic manipulation of these parasites via electroporation is proven, but this method is cumbersome and time consuming. Here we report our endeavour to develop a rapid and simple transfection method by gene gun. Tungsten particles coated with plasmid DNA encoding enhanced yellow fluorescent protein (EYFP) were used for the bombardment of Eimeria maxima unsporulated oocysts. Seven Mpa (1015 psi) helium pressure, 65 mm target distance and -0.098 Mpa (24.8″ Hg) chamber vacuum were the optimised parameters for bombardment. After sporulation, the bombarded oocysts were inoculated into chickens, and the progeny oocysts were checked under fluorescent microscope and subjected to genomic DNA extraction, which was used either for polymerase chain reaction (PCR) amplification or plasmid rescue assay. Although the expression of EYFP was not observed, the gene was amplified from both genomic DNA and the rescued plasmid, suggesting that the plasmid DNA existed in the form of episome. These results are encouraging for the genetic processing of the sporogony stage of eimerian parasites.
Collapse
Affiliation(s)
- Jianan Li
- 1 China Agricultural University National Animal Protozoa Laboratory, College of Veterinary Medicine Yuanmingyuan West Road 2, Haidian District Beijing 100193 China
| | - Jun Zou
- 1 China Agricultural University National Animal Protozoa Laboratory, College of Veterinary Medicine Yuanmingyuan West Road 2, Haidian District Beijing 100193 China
| | - Guangwen Yin
- 1 China Agricultural University National Animal Protozoa Laboratory, College of Veterinary Medicine Yuanmingyuan West Road 2, Haidian District Beijing 100193 China
| | - Xianyong Liu
- 1 China Agricultural University National Animal Protozoa Laboratory, College of Veterinary Medicine Yuanmingyuan West Road 2, Haidian District Beijing 100193 China
| | - Xun Suo
- 1 China Agricultural University National Animal Protozoa Laboratory, College of Veterinary Medicine Yuanmingyuan West Road 2, Haidian District Beijing 100193 China
| |
Collapse
|
28
|
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: 56] [Impact Index Per Article: 4.7] [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.
Collapse
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
| |
Collapse
|
29
|
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.
Collapse
Affiliation(s)
- Yousef Noori Alrefaei
- Department of Microbiology, Immunology and Tropical Medicine, George Washington University Medical Center, Washington, DC, USA
| | | | | | | |
Collapse
|
30
|
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.
Collapse
Affiliation(s)
- J Hagen
- Department of Veterinary Science, Centre for Animal Biotechnology, The University of Melbourne, Vic., Australia
| | | | | | | |
Collapse
|
31
|
Abstract
Transgenesis is an essential tool for assessing gene function in any organism, and it is especially crucial for parasitic nematodes given the dwindling armamentarium of effective anthelmintics and the consequent need to validate essential molecular targets for new drugs and vaccines. Two of the major routes of gene delivery evaluated to date in parasitic nematodes, bombardment with DNA-coated microparticles and intragonadal microinjection of DNA constructs, draw upon experience with the free-living nematode Caenorhabditis elegans. Bombardment has been used to transiently transfect Ascaris suum, Brugia malayi and Litomosoides sigmodontis with both RNA and DNA. Microinjection has been used to achieve heritable transgenesis in Strongyloides stercoralis, S. ratti and Parastrongyloides trichosuri and for additional transient expression studies in B. malayi. A third route of gene delivery revisits a classic method involving DNA transfer facilitated by calcium-mediated permeabilization of recipient cells in developing B. malayi larvae and results in transgene inheritance through host and vector passage. Assembly of microinjected transgenes into multi-copy episomal arrays likely results in their transcriptional silencing in some parasitic nematodes. Methods such as transposon-mediated transgenesis that favour low-copy number chromosomal integration may remedy this impediment to establishing stable transgenic lines. In the future, stable transgenesis in parasitic nematodes could enable loss-of-function approaches by insertional mutagenesis, in situ expression of inhibitory double-stranded RNA or boosting RNAi susceptibility through heterologous expression of dsRNA processing and transport proteins.
Collapse
Affiliation(s)
- James B Lok
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104, USA.
| |
Collapse
|
32
|
Selkirk ME, Huang SC, Knox DP, Britton C. The development of RNA interference (RNAi) in gastrointestinal nematodes. Parasitology 2012; 139:605-12. [PMID: 22459433 DOI: 10.1017/s0031182011002332] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Despite the utility of RNAi for defining gene function in Caenorhabditis elegans and early successes reported in parasitic nematodes, RNAi has proven to be stubbornly inconsistent or ineffective in the animal parasitic nematodes examined to date. Here, we summarise some of our experiences with RNAi in parasitic nematodes affecting animals and discuss the available data in the context of our own unpublished work, taking account of mode of delivery, larval activation, site of gene transcription and the presence/absence of essential RNAi pathway genes as defined by comparisons to C. elegans. We discuss future directions briefly including the evaluation of nanoparticles as a means to enhance delivery of interfering RNA to the target worm tissue.
Collapse
Affiliation(s)
- Murray E Selkirk
- Division of Cell and Molecular Biology, Department of Life Sciences, Imperial College London, London SW7 2AZ
| | | | | | | |
Collapse
|
33
|
Yu H, Chen Y. Nanotechnology for DNA and RNA delivery. Nanomedicine (Lond) 2012. [DOI: 10.1533/9780857096449.2.302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
34
|
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.
Collapse
|
35
|
Wang J, Czech B, Crunk A, Wallace A, Mitreva M, Hannon GJ, Davis RE. Deep small RNA sequencing from the nematode Ascaris reveals conservation, functional diversification, and novel developmental profiles. Genome Res 2011; 21:1462-77. [PMID: 21685128 PMCID: PMC3166831 DOI: 10.1101/gr.121426.111] [Citation(s) in RCA: 145] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 06/08/2011] [Indexed: 11/24/2022]
Abstract
Eukaryotic cells express several classes of small RNAs that regulate gene expression and ensure genome maintenance. Endogenous siRNAs (endo-siRNAs) and Piwi-interacting RNAs (piRNAs) mainly control gene and transposon expression in the germline, while microRNAs (miRNAs) generally function in post-transcriptional gene silencing in both somatic and germline cells. To provide an evolutionary and developmental perspective on small RNA pathways in nematodes, we identified and characterized known and novel small RNA classes through gametogenesis and embryo development in the parasitic nematode Ascaris suum and compared them with known small RNAs of Caenorhabditis elegans. piRNAs, Piwi-clade Argonautes, and other proteins associated with the piRNA pathway have been lost in Ascaris. miRNAs are synthesized immediately after fertilization in utero, before pronuclear fusion, and before the first cleavage of the zygote. This is the earliest expression of small RNAs ever described at a developmental stage long thought to be transcriptionally quiescent. A comparison of the two classes of Ascaris endo-siRNAs, 22G-RNAs and 26G-RNAs, to those in C. elegans, suggests great diversification and plasticity in the use of small RNA pathways during spermatogenesis in different nematodes. Our data reveal conserved characteristics of nematode small RNAs as well as features unique to Ascaris that illustrate significant flexibility in the use of small RNAs pathways, some of which are likely an adaptation to Ascaris' life cycle and parasitism. The transcriptome assembly has been submitted to NCBI Transcriptome Shotgun Assembly Sequence Database(http://www.ncbi.nlm.nih.gov/genbank/TSA.html) under accession numbers JI163767–JI182837 and JI210738–JI257410.
Collapse
Affiliation(s)
- Jianbin Wang
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin Czech
- Watson School of Biological Sciences, HHMI, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Amanda Crunk
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Adam Wallace
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Makedonka Mitreva
- Genetics and Genome Center, Washington University School of Medicine, St. Louis, Missouri 63108, USA
| | - Gregory J. Hannon
- Watson School of Biological Sciences, HHMI, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York 11724, USA
| | - Richard E. Davis
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| |
Collapse
|
36
|
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.
Collapse
|
37
|
Gregory WF, Parkinson J. Caenorhabditis elegans-applications to nematode genomics. Comp Funct Genomics 2011; 4:194-202. [PMID: 18629128 PMCID: PMC2447415 DOI: 10.1002/cfg.260] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2003] [Accepted: 01/30/2003] [Indexed: 11/06/2022] Open
Abstract
The complete genome sequence of the free-living nematode Caenorhabditis elegans was published 4 years ago. Since then, we have seen great strides in technologies that seek to exploit this data. Here we describe the application of some of these techniques and other advances that are helping us to understand about not only the biology of this important model organism but also the entire phylum Nematoda.
Collapse
Affiliation(s)
- William F Gregory
- Institute of Cell Animal and Population Biology Kings Buildings West Mains Rd Edinburgh EH9 3JT UK
| | | |
Collapse
|
38
|
Tchoubrieva E, Kalinna B. Advances in mRNA silencing and transgene expression: a gateway to functional genomics in schistosomes. Biotechnol Genet Eng Rev 2011; 26:261-80. [PMID: 21415884 DOI: 10.5661/bger-26-261] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The completion of the WHO Schistosoma Genome Project in 2008, although not fully annotated, provides a golden opportunity to actively pursue fundamental research on the parasites genome. This analysis will aid identification of targets for drugs, vaccines and markers for diagnostic tools as well as for studying the biological basis of drug resistance, infectivity and pathology. For the validation of drug and vaccine targets, the genomic sequence data is only of use if functional analyses can be conducted (in the parasite itself). Until recently, gene manipulation approaches had not been seriously addressed. This situation is now changing and rapid advances have been made in gene silencing and transgenesis of schistosomes.
Collapse
Affiliation(s)
- Elissaveta Tchoubrieva
- Centre for Animal Biotechnology, Faculty of Veterinary Science, The University of Melbourne, Parkville, 3010 VIC, Australia
| | | |
Collapse
|
39
|
Yang S, Brindley PJ, Zeng Q, Li Y, Zhou J, Liu Y, Liu B, Cai L, Zeng T, Wei Q, Lan L, McManus DP. Transduction of Schistosoma japonicum schistosomules with vesicular stomatitis virus glycoprotein pseudotyped murine leukemia retrovirus and expression of reporter human telomerase reverse transcriptase in the transgenic schistosomes. Mol Biochem Parasitol 2010; 174:109-16. [PMID: 20692298 PMCID: PMC3836731 DOI: 10.1016/j.molbiopara.2010.07.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2009] [Revised: 07/25/2010] [Accepted: 07/28/2010] [Indexed: 01/21/2023]
Abstract
Although draft genome sequences of two of the major human schistosomes, Schistosoma japonicum and Schistosoma mansoni are available, the structures and characteristics of most genes and the influence of exogenous genes on the metabolism of schistosomes remain uncharacterized. Furthermore, which functional genomics approaches will be tractable for schistosomes are not yet apparent. Here, the vesicular stomatitis virus glycoprotein (VSVG)-pseudotyped pantropic retroviral vector pBABE-puro was modified to incorporate the human telomerase reverse transcriptase gene (hTERT) as a reporter, under the control of the retroviral long terminal repeat (LTR). Pseudotyped virions were employed to transduce S. japonicum to investigate the utility of retrovirus-mediated transgenesis of S. japonicum and the activity of human telomerase reverse transcriptase as a reporter transgene in schistosomes. Schistosomules perfused from experimentally infected rabbits were cultured for 6 days after exposure to the virions after which genomic DNAs from virus exposed and control worms were extracted. Analysis of RNA from transduced parasites and immunohistochemistry of thin parasite sections revealed expression of hTERT in the transduced worms. Expression of hTERT was also confirmed by immunoblot analysis. These findings indicated that S. japonicum could be effectively transduced by VSVG-pseudotyped retrovirus carrying the hTERT gene. Given the potential of hTERT to aid in derivation of immortalized cells, these findings suggest that this pantropic retroviral approach can be employed to transduce cells from specific tissues and organs of schistosomes to investigate the influence of transgene hTERT on growth and proliferation of schistosome cells.
Collapse
Affiliation(s)
- Shenghui Yang
- Centre of Cell and Molecular Biology Experiment, Xiangya School of Medicine, Central South University, Changsha, Hunan province, China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Ribeiro P, Geary TG. Neuronal signaling in schistosomes: current status and prospects for postgenomicsThe present review is one of a series of occasional review articles that have been invited by the Editors and will feature the broad range of disciplines and expertise represented in our Editorial Advisory Board. CAN J ZOOL 2010. [DOI: 10.1139/z09-126] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Parasitic platyhelminths of the genus Schistosoma Weinland, 1858 (Trematoda, Digenea) are the etiological agents of human schistosomiasis, one of the most prevalent and debilitating parasitic diseases worldwide. Praziquantel is the only drug treatment available in most parts of the world and the effectiveness of the drug is threatened by the prospect of drug resistance. There is a pressing need to learn more about the basic biology of this organism and to identify molecular targets for new therapeutic drugs. The nervous system of schistosomes coordinates many activities that are essential for parasite survival, and as such is an attractive target for chemotherapeutic intervention. Until recently, very little was known about the molecular mechanisms of neuronal signaling in these organisms, but this is rapidly changing following the completion of the genome sequence and several recent developments in schistosome transgenesis and gene silencing. Here we review the current status of schistosome neurobiology and discuss prospects for future research as the field moves into a postgenomics era. One of the themes that will emerge from this discussion is that schistosomes have a rich diversity of neurotransmitters and receptors, indicating a more sophisticated system of neuronal communication than might be expected of a parasitic flatworm. Moreover, many of these transmitter receptors share little sequence homology with those of the human host, making them ideally suited for selective drug targeting. Strategies for characterization of these important parasite proteins will be discussed.
Collapse
Affiliation(s)
- Paula Ribeiro
- Institute of Parasitology, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
| | - Timothy G. Geary
- Institute of Parasitology, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste. Anne de Bellevue, QC H9X 3V9, Canada
| |
Collapse
|
41
|
Han ZG, Brindley PJ, Wang SY, Chen Z. Schistosoma genomics: new perspectives on schistosome biology and host-parasite interaction. Annu Rev Genomics Hum Genet 2009; 10:211-40. [PMID: 19630560 DOI: 10.1146/annurev-genom-082908-150036] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Schistosomiasis, caused mainly by Schistosoma japonicum, S. mansoni, and S. hematobium, remains one of the most prevalent and serious parasitic diseases worldwide. The blood flukes have a complex life cycle requiring adaptation for survival in fresh water as free-living forms and as parasites in snail intermediate and vertebrate definitive hosts. Functional genomics analyses, including transcriptomic and proteomic approaches, have been performed on schistosomes, in particular S. mansoni and S. japonicum, using powerful high-throughput methodologies. These investigations have not only chartered gene expression profiles across genders and developmental stages within mammalian and snail hosts, but have also characterized the features of the surface tegument, the eggshell and excretory-secretory proteomes of schistosomes. The integration of the genomic, transcriptomic, and proteomic information, together with genetic manipulation on individual genes, will provide a global insight into the molecular architecture of the biology, pathogenesis, and host-parasite interactions of the human blood flukes. Importantly, these functional genomics analyses lay a foundation on which to develop new antischistosome vaccines as well as drug targets and diagnostic markers for treatment and control of schistosomiasis.
Collapse
Affiliation(s)
- Ze-Guang Han
- Shanghai-MOST Key Laboratory for Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai 201203, China.
| | | | | | | |
Collapse
|
42
|
Rinaldi G, Morales ME, Cancela M, Castillo E, Brindley PJ, Tort JF. Development of functional genomic tools in trematodes: RNA interference and luciferase reporter gene activity in Fasciola hepatica. PLoS Negl Trop Dis 2008; 2:e260. [PMID: 18612418 PMCID: PMC2440534 DOI: 10.1371/journal.pntd.0000260] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2007] [Accepted: 06/11/2008] [Indexed: 02/03/2023] Open
Abstract
The growing availability of sequence information from diverse parasites through genomic and transcriptomic projects offer new opportunities for the identification of key mediators in the parasite–host interaction. Functional genomics approaches and methods for the manipulation of genes are essential tools for deciphering the roles of genes and to identify new intervention targets in parasites. Exciting advances in functional genomics for parasitic helminths are starting to occur, with transgene expression and RNA interference (RNAi) reported in several species of nematodes, but the area is still in its infancy in flatworms, with reports in just three species. While advancing in model organisms, there is a need to rapidly extend these technologies to other parasites responsible for several chronic diseases of humans and cattle. In order to extend these approaches to less well studied parasitic worms, we developed a test method for the presence of a viable RNAi pathway by silencing the exogenous reporter gene, firefly luciferase (fLUC). We established the method in the human blood fluke Schistosoma mansoni and then confirmed its utility in the liver fluke Fasciola hepatica. We transformed newly excysted juveniles of F. hepatica by electroporation with mRNA of fLUC and three hours later were able to detect luciferase enzyme activity, concentrated mainly in the digestive ceca. Subsequently, we tested the presence of an active RNAi pathway in F. hepatica by knocking down the exogenous luciferase activity by introduction into the transformed parasites of double-stranded RNA (dsRNA) specific for fLUC. In addition, we tested the RNAi pathway targeting an endogenous F. hepatica gene encoding leucine aminopeptidase (FhLAP), and observed a significant reduction in specific mRNA levels. In summary, these studies demonstrated the utility of RNAi targeting reporter fLUC as a reporter gene assay to establish the presence of an intact RNAi pathway in helminth parasites. These could facilitate the study of gene function and the identification of relevant targets for intervention in organisms that are by other means intractable. More specifically, these results open new perspectives for functional genomics of F. hepatica, which hopefully can lead to the development of new interventions for fascioliasis. Reverse genetics tools allow assessing the function of unknown genes. Their application for the study of neglected infectious diseases could lead eventually to the identification of relevant gene products to be used in diagnosis, or as drug targets or immunization candidates. Being technically more simple and less demanding than other reverse genetics tools such as transgenesis or knockouts, the suppression of gene activity mediated by double-stranded RNA has emerged as a powerful tool for the analysis of gene function. RNAi appeared as an obvious alternative to apply in complex biological systems where information is still scarce, a situation common to several infectious and parasitic diseases. However, several technical or practical difficulties have hampered the development of this technique in parasites to the expectations originally generated. We developed a simple method to test the presence of a viable RNAi pathway by silencing an exogenous reporter gene. The method was tested in F. hepatica, describing the conditions for transfection and confirming the existence of a viable RNAi pathway in this parasite. The experimental design created can be useful as a first approach in organisms where genetic analysis is still unavailable, providing a tool to unravel gene function and probably advancing new candidates relevant in pathobiology, prevention or treatment.
Collapse
Affiliation(s)
- Gabriel Rinaldi
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
- Departamento de Genética, Facultad de Medicina, Universidad de la República, Udelar, Montevideo, Uruguay
| | - Maria E. Morales
- Department of Tropical Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, United States of America
| | - Martín Cancela
- Departamento de Genética, Facultad de Medicina, Universidad de la República, Udelar, Montevideo, Uruguay
| | - Estela Castillo
- Sección Bioquímica, Facultad de Ciencias, Universidad de la República, Udelar, Montevideo, Uruguay
| | - Paul J. Brindley
- Department of Tropical Medicine, 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
- * E-mail:
| |
Collapse
|
43
|
Abstract
There is increasing interest in the use of the free-living nematode Caenorhabditis elegans as a tool for parasitic nematode research and there are now a number of compelling examples of its successful application. C. elegans has the potential to become a standard tool for molecular helminthology researchers, just as yeast is routinely used by molecular biologists to study vertebrate biology. However, in order to exploit C. elegans in a meaningful manner, we need a detailed understanding of the extent to which different aspects of C. elegans biology have been conserved with particular groups of parasitic nematodes. This review first considers the current state of knowledge regarding the conservation of genome organisation across the nematode phylum and then discusses some recent evolutionary development studies in free-living nematodes. The aim is to provide some important concepts that are relevant to the extrapolation of information from C. elegans to parasitic nematodes and also to the interpretation of experiments that use C. elegans as a surrogate expression system. In general, examples have been specifically chosen because they highlight the importance of careful experimentation and interpretation of data. Consequently, the focus is on the differences that have been found between nematode species rather than the similarities. Finally, there is a detailed discussion of the current status of C. elegans as a heterologous expression system to study parasite gene function and regulation using successful examples from the literature.
Collapse
Affiliation(s)
- J S Gilleard
- Department of Veterinary Parasitology, Institute of Comparative Medicine, Faculty of Veterinary Medicine, University of Glasgow, Glasgow, UK.
| |
Collapse
|
44
|
Lok JB, Artis D. Transgenesis and neuronal ablation in parasitic nematodes: revolutionary new tools to dissect host-parasite interactions. Parasite Immunol 2008; 30:203-14. [PMID: 18324923 DOI: 10.1111/j.1365-3024.2008.01006.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Ease of experimental gene transfer into viral and prokaryotic pathogens has made transgenesis a powerful tool for investigating the interactions of these pathogens with the host immune system. Recent advances have made this approach feasible for more complex protozoan parasites. By contrast, the lack of a system for heritable transgenesis in parasitic nematodes has hampered progress toward understanding the development of nematode-specific cellular responses. Recently, however, significant strides towards such a system have been made in several parasitic nematodes, and the possible applications of these in immunological research should now be contemplated. In addition, methods for targeted cell ablation have been successfully adapted from Caenorhabditis elegans methodology and applied to studies of neurobiology and behaviour in Strongyloides stercoralis. Together, these new technical developments offer exciting new tools to interrogate multiple aspects of the host-parasite interaction following nematode infection.
Collapse
Affiliation(s)
- J B Lok
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6008, USA.
| | | |
Collapse
|
45
|
Abstract
Draft genome sequences for Schistosoma mansoni and Schistosoma japonicum are now available. However, the identity and importance of most schistosome genes have yet to be determined. Recently, progress has been made towards the genetic manipulation and transgenesis of schistosomes. Both loss-of-function and gain-of-function approaches appear to be feasible in schistosomes based on findings described in the past 5 years. This review focuses on reports of schistosome transgenesis, specifically those dealing with the transformation of schistosomes with exogenous mobile genetic elements and/or their endogenous relatives for the genetic manipulation of schistosomes. Transgenesis mediated by mobile genetic elements offers a potentially tractable route to introduce foreign genes to schistosomes, a means to determine the importance of schistosome genes, including those that could be targeted in novel interventions and the potential to undertake large-scale forward genetics by insertional mutagenesis.
Collapse
|
46
|
Junio AB, Li X, Massey HC, Nolan TJ, Todd Lamitina S, Sundaram MV, Lok JB. Strongyloides stercoralis: cell- and tissue-specific transgene expression and co-transformation with vector constructs incorporating a common multifunctional 3' UTR. Exp Parasitol 2007; 118:253-65. [PMID: 17945217 DOI: 10.1016/j.exppara.2007.08.018] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2007] [Revised: 08/21/2007] [Accepted: 08/28/2007] [Indexed: 11/26/2022]
Abstract
Transgenesis is a valuable methodology for studying gene expression patterns and gene function. It has recently become available for research on some parasitic nematodes, including Strongyloides stercoralis. Previously, we described a vector construct, comprising the promoter and 3' UTR of the S. stercoralis gene Ss era-1 that gives expression of GFP in intestinal cells of developing F1 progeny. In the present study, we identified three new S. stercoralis promoters, which, in combination with the Ss era-1 3' UTR, can drive expression of GFP or the red fluorescent protein, mRFPmars, in tissue-specific fashion. These include Ss act-2, which drives expression in body wall muscle cells, Ss gpa-3, which drives expression in amphidial and phasmidial neurons and Ss rps-21, which drives ubiquitous expression in F1 transformants and in the gonads of microinjected P0 female worms. Concomitant microinjection of vectors containing GFP and mRFPmars gave dually transformed F1 progeny, suggesting that these constructs could be used as co-injection markers for other transgenes of interest. We have developed a vector "toolkit" for S. stercoralis including constructs with the Ss era-1 3' UTR and each of the promoters described above.
Collapse
Affiliation(s)
- Ariel B Junio
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | | | | | | | | |
Collapse
|
47
|
Ribeiro P, El-Shehabi F, Patocka N. Classical transmitters and their receptors in flatworms. Parasitology 2007; 131 Suppl:S19-40. [PMID: 16569290 DOI: 10.1017/s0031182005008565] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The flatworm nervous system employs a wide repertoire of neuroactive substances, including small chemical messengers, the so called classical transmitters, and several types of neuropeptides. A large body of research accumulated over four decades has provided a wealth of information on the tissue localization and effects of these substances, their biochemistry and, recently, their molecular modes of action in all major classes of flatworms. This evidence will be reviewed, with particular emphasis on the small (classical) transmitters and the receptors that mediate their effects. One of the themes that will emerge from this discussion is that classical transmitters regulate core activities such as movement, metabolism and transport, and thus are essential for survival of the organism. In addition, the evidence shows that flatworms have multiple neurotransmitter receptors, many with unusual pharmacological features, which make them particularly attractive as drug targets. Understanding the molecular basis of these distinctive properties, and developing new, more specific receptor agonists and antagonists will undoubtedly become a major challenge in future research.
Collapse
Affiliation(s)
- P Ribeiro
- Institute of Parasitology, McGill University, Macdonald Campus, 21,111 Lakeshore Road, Ste. Anne de Bellevue Quebec, Canada H9X 3V9.
| | | | | |
Collapse
|
48
|
Cheng G, Davis RE. An improved and secreted luciferase reporter for schistosomes. Mol Biochem Parasitol 2007; 155:167-71. [PMID: 17681388 PMCID: PMC3641815 DOI: 10.1016/j.molbiopara.2007.06.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Revised: 06/25/2007] [Accepted: 06/27/2007] [Indexed: 01/22/2023]
Abstract
Schistosomes are multicellular parasites of humans exhibiting interesting biological adaptations to their parasitic lifestyle. Concerted and in depth analyses of these adaptations and their cell and molecular biology requires further development of molecular genetic tools in schistosomes. In the current study, we demonstrate that a Gaussia luciferase reporter leads to significantly higher levels of luciferase activity in schistosomes compared to other tested luciferases. In addition, Gaussia luciferase can be secreted into culture media enabling non-invasive analysis of reporter activity. The secretion of Gaussia luciferase should allow a variety of new experimental paradigms for schistosome studies. Comparison of biolistic and electroporation transfection methods using luciferase RNA reporters and the luciferase acitivty produced indicates that electroporation of sporocysts and schistosomula is the most efficient transfection method for the four stages analyzed. These data should facilitate additional studies in schistosomes and provide a framework for further development of DNA transfection and gene expression analysis.
Collapse
Affiliation(s)
| | - Richard E. Davis
- Address correspondence to: Dr. Richard E. Davis, Departments of Pediatrics and Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Mail Stop 8101, RC-1 South, P.O. Box 6511, 12801 East 17th Avenue, Aurora, CO 80045; Tel: 303-724-3226; Fax: 303-724-3215;
| |
Collapse
|
49
|
Morales ME, Mann VH, Kines KJ, Gobert GN, Fraser MJ, Kalinna BH, Correnti JM, Pearce EJ, Brindley PJ. piggyBac transposon mediated transgenesis of the human blood fluke, Schistosoma mansoni. FASEB J 2007; 21:3479-89. [PMID: 17586730 DOI: 10.1096/fj.07-8726com] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The transposon piggyBac from the genome of the cabbage looper moth Trichoplusia ni has been observed in the laboratory to jump into the genomes of key model and pathogenic eukaryote organisms including mosquitoes, planarians, human and other mammalian cells, and the malaria parasite Plasmodium falciparum. Introduction of exogenous transposons into schistosomes has not been reported but transposon-mediated transgenesis of schistosomes might supersede current methods for functional genomics of this important human pathogen. In the present study we examined whether the piggyBac transposon could deliver reporter transgenes into the genome of Schistosoma mansoni parasites. A piggyBac donor plasmid modified to encode firefly luciferase under control of schistosome gene promoters was introduced along with 7-methylguanosine capped RNAs encoding piggyBac transposase into cultured schistosomula by square wave electroporation. The activity of the helper transposase mRNA was confirmed by Southern hybridization analysis of genomic DNA from the transformed schistosomes, and hybridization signals indicated that the piggyBac transposon had integrated into numerous sites within the parasite chromosomes. piggyBac integrations were recovered by retrotransposon-anchored PCR, revealing characteristic piggyBac TTAA footprints in the vicinity of the endogenous schistosome retrotransposons Boudicca, SR1, and SR2. This is the first report of chromosomal integration of a transgene and somatic transgenesis of this important human pathogen, in this instance accomplished by mobilization of the piggyBac transposon.
Collapse
Affiliation(s)
- Maria E Morales
- Department of Tropical Medicine, Tulane University, Health Sciences Center, 1430 Tulane Ave., New Orleans, LA 70112, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Cheng G, Cohen L, Mikhli C, Jankowska-Anyszka M, Stepinski J, Darzynkiewicz E, Davis RE. In vivo translation and stability of trans-spliced mRNAs in nematode embryos. Mol Biochem Parasitol 2007; 153:95-106. [PMID: 17391777 PMCID: PMC3650844 DOI: 10.1016/j.molbiopara.2007.02.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2007] [Revised: 02/12/2007] [Accepted: 02/13/2007] [Indexed: 11/23/2022]
Abstract
Spliced leader trans-splicing adds a short exon, the spliced leader (SL), to pre-mRNAs to generate 5' ends of mRNAs. Addition of the SL in metazoa also adds a new cap to the mRNA, a trimethylguanosine (m(3)(2,2,7)GpppN) (TMG) that replaces the typical eukaryotic monomethylguanosine (m7GpppN)(m7G) cap. Both trans-spliced (m3(2,2,7)GpppN-SL-RNA) and not trans-spliced (m7GpppN-RNA) mRNAs are present in the same cells. Previous studies using cell-free systems to compare the overall translation of trans-spliced versus non-trans-spliced RNAs led to different conclusions. Here, we examine the contribution of m3(2,2,7)GpppG-cap and SL sequence and other RNA elements to in vivo mRNA translation and stability in nematode embryos. Although 70-90% of all nematode mRNAs have a TMG-cap, the TMG cap does not support translation as well as an m7G-cap. However, when the TMG cap and SL are present together, they synergistically interact and translation is enhanced, indicating both trans-spliced elements are necessary to promote efficient translation. The SL by itself does not act as a cap-independent enhancer of translation. The poly(A)-tail synergistically interacts with the mRNA cap enhancing translation and plays a greater role in facilitating translation of TMG-SL mRNAs. In general, recipient mRNA sequences between the SL and AUG and the 3' UTR do not significantly contribute to the translation of trans-spliced mRNAs. Overall, the combination of TMG cap and SL contribute to mRNA translation and stability in a manner typical of a eukaryotic m7G-cap and 5' UTRs, but they do not differentially enhance mRNA translation or stability compared to RNAs without the trans-spliced elements.
Collapse
Affiliation(s)
- Guofeng Cheng
- Departments of Pediatrics and Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
| | - Leah Cohen
- Department of Biology, City University of New York Graduate Center, CSI, 2800 Victory Boulevard, Staten Island, NY, 10314 and
| | - Claudette Mikhli
- Department of Biology, City University of New York Graduate Center, CSI, 2800 Victory Boulevard, Staten Island, NY, 10314 and
| | | | - Janusz Stepinski
- Departments of Biophysics, University of Warsaw, 02-089 Warsaw, Poland
| | | | - Richard E. Davis
- Departments of Pediatrics and Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO 80045
- Department of Biology, City University of New York Graduate Center, CSI, 2800 Victory Boulevard, Staten Island, NY, 10314 and
| |
Collapse
|