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Lustigman S, Geldhof P, Grant WN, Osei-Atweneboana MY, Sripa B, Basáñez MG. A research agenda for helminth diseases of humans: basic research and enabling technologies to support control and elimination of helminthiases. PLoS Negl Trop Dis 2012; 6:e1445. [PMID: 22545160 PMCID: PMC3335859 DOI: 10.1371/journal.pntd.0001445] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Successful and sustainable intervention against human helminthiases depends on optimal utilisation of available control measures and development of new tools and strategies, as well as an understanding of the evolutionary implications of prolonged intervention on parasite populations and those of their hosts and vectors. This will depend largely on updated knowledge of relevant and fundamental parasite biology. There is a need, therefore, to exploit and apply new knowledge and techniques in order to make significant and novel gains in combating helminthiases and supporting the sustainability of current and successful mass drug administration (MDA) programmes. Among the fields of basic research that are likely to yield improved control tools, the Disease Reference Group on Helminth Infections (DRG4) has identified four broad areas that stand out as central to the development of the next generation of helminth control measures: 1) parasite genetics, genomics, and functional genomics; 2) parasite immunology; 3) (vertebrate) host–parasite interactions and immunopathology; and 4) (invertebrate) host–parasite interactions and transmission biology. The DRG4 was established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR). The Group was given the mandate to undertake a comprehensive review of recent advances in helminthiases research in order to identify notable gaps and highlight priority areas. This paper summarises recent advances and discusses challenges in the investigation of the fundamental biology of those helminth parasites under the DRG4 Group's remit according to the identified priorities, and presents a research and development agenda for basic parasite research and enabling technologies that will help support control and elimination efforts against human helminthiases.
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Affiliation(s)
- Sara Lustigman
- Laboratory of Molecular Parasitology, Lindsley F. Kimball Research Institute, New York Blood Center, New York, New York, USA.
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Wang X, Chen W, Lv X, Tian Y, Men J, Zhang X, Lei H, Zhou C, Lu F, Liang C, Hu X, Xu J, Wu Z, Li X, Yu X. Identification and characterization of paramyosin from cyst wall of metacercariae implicated protective efficacy against Clonorchis sinensis infection. PLoS One 2012; 7:e33703. [PMID: 22470461 PMCID: PMC3312334 DOI: 10.1371/journal.pone.0033703] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Accepted: 02/20/2012] [Indexed: 12/14/2022] Open
Abstract
Human clonorchiasis has been increasingly prevalent in recent years and results in a threat to the public health in epidemic regions, motivating current strategies of vaccines to combat Clonorchis sinensis (C. sinensis). In this study, we identified C. sinensis paramyosin (CsPmy) from the cyst wall proteins of metacercariae by proteomic approaches and characterized the expressed recombinant pET-26b-CsPmy protein (101 kDa). Bioinformatics analysis indicated that full-length sequences of paramyosin are conserved in helminthes and numerous B-cell/T-cell epitopes were predicted in amino acid sequence of CsPmy. Western blot analysis showed that CsPmy was expressed at four life stages of C. sinensis, both cyst wall proteins and soluble tegumental components could be probed by anti-CsPmy serum. Moreover, immunolocalization results revealed that CsPmy was specifically localized at cyst wall and excretory bladder of metacercaria, as well as the tegument, oral sucker and vitellarium of adult worm. Both immunoblot and immunolocalization results demonstrated that CsPmy was highly expressed at the stage of adult worm, metacercariae and cercaria, which could be supported by real-time PCR analysis. Both recombinant protein and nucleic acid of CsPmy showed strong immunogenicity in rats and induced combined Th1/Th2 immune responses, which were reflected by continuous high level of antibody titers and increased level of IgG1/IgG2a subtypes in serum. In vaccine trials, comparing with control groups, both CsPmy protein and DNA vaccine exhibited protective effect with significant worm reduction rate of 54.3% (p<0.05) and 36.1% (p<0.05), respectively. In consistence with immune responses in sera, elevated level of cytokines IFN-γ and IL-4 in splenocytes suggested that CsPmy could induce combined cellular immunity and humoral immunity in host. Taken together, CsPmy could be a promising vaccine candidate in the prevention of C. sinensis regarding its high immunogenicity and surface localization.
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Affiliation(s)
- Xiaoyun Wang
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Wenjun Chen
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Xiaoli Lv
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Yanli Tian
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Jingtao Men
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Xifeng Zhang
- Department of Biological and Pharmaceutical Engineering, Wuhan Polytechnic University, Wuhan, Hubei, People's Republic of China
| | - Huali Lei
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Chenhui Zhou
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Fangli Lu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Chi Liang
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Xuchu Hu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Jin Xu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Zhongdao Wu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
| | - Xuerong Li
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- * E-mail: (XL); (XY)
| | - Xinbing Yu
- Department of Parasitology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- Key Laboratory for Tropical Diseases Control of Ministry of Education, Sun Yat-sen University, Guangzhou, Guangdong, People's Republic of China
- * E-mail: (XL); (XY)
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Abstract
Intravascular schistosome parasites are covered by an unusual double lipid bilayer. Nutrients, such as glucose and amino acids, as well as other metabolites, are known to be transported across this surface via specific transporter proteins. For instance, the glucose transporter protein SGTP4 is found in the host-interactive tegumental membranes. A second glucose transporter, SGTP1, localizes to the tegumental basal membrane (and internal tissues). Following expression in Xenopus oocytes, SGTP1 and SGTP4 both function as facilitated-diffusion sugar transporters. Suppressing the expression of SGTP1 and SGTP4 in juvenile schistosomes using RNA interference (RNAi) impairs the parasite's ability to import glucose and severely decreases worm viability. Amino acids can also be imported into schistosomes across their surface and an amino acid transporter (SPRM1lc) has been localized in the parasite surface membranes (as well as internally). In Xenopus oocytes, SPRM1lc can import the basic amino acids arginine, lysine and histidine as well as leucine, phenylalanine, methionine and glutamine. To function, this protein requires the assistance of a heavy-chain partner (SPRM1hc) which acts as a chaperone. Water is transported across the tegument of schistosomes via the aquaporin protein SmAQP. Suppressing SmAQP gene expression makes the parasites less able to osmoregulate and decreases their viability. In addition, SmAQP-suppressed adult parasites have been shown to be impaired in their ability to excrete lactate. Analysis of tegumental transporter proteins, as described in this report, is designed to generate a comprehensive understanding of the role of such proteins in promoting parasite survival by controlling the movement of metabolites into and out of the worms.
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Swain MT, Larkin DM, Caffrey CR, Davies SJ, Loukas A, Skelly PJ, Hoffmann KF. Schistosoma comparative genomics: integrating genome structure, parasite biology and anthelmintic discovery. Trends Parasitol 2011; 27:555-64. [PMID: 22024648 PMCID: PMC3223292 DOI: 10.1016/j.pt.2011.09.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/09/2011] [Accepted: 09/20/2011] [Indexed: 12/11/2022]
Abstract
Schistosoma genomes provide a comprehensive resource for identifying the molecular processes that shape parasite evolution and for discovering novel chemotherapeutic or immunoprophylactic targets. Here, we demonstrate how intragenus and intergenus comparative genomics can be used to drive these investigations forward, illustrate the advantages and limitations of these approaches and review how post-genomic technologies offer complementary strategies for genome characterisation. Although sequencing and functional characterisation of other schistosome/platyhelminth genomes continues to expedite anthelmintic discovery, we contend that future priorities should equally focus on improving assembly quality, and chromosomal assignment, of existing schistosome/platyhelminth genomes.
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Affiliation(s)
- Martin T Swain
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, UK
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55
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Walker AJ. Insights into the functional biology of schistosomes. Parasit Vectors 2011; 4:203. [PMID: 22013990 PMCID: PMC3206467 DOI: 10.1186/1756-3305-4-203] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Accepted: 10/20/2011] [Indexed: 01/27/2023] Open
Abstract
The need to discover new treatments for human schistosomiasis has been an important driver for molecular research on schistosomes, a major breakthrough being the publication of the Schistosoma mansoni and Schistosoma japonicum genomes in 2009. This 'Primer' considers recent advances in the understanding of schistosome biology by providing a snapshot of selected areas of contemporary functional schistosome research, including that on the genome, the tegument, cell signalling and developmental biology, offering biologists a valuable insight into the life of these fascinating parasites at the basic and molecular level.
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Affiliation(s)
- Anthony John Walker
- School of Life Sciences, Kingston University, Kingston upon Thames, Surrey KT12EE, UK.
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Computational vaccinology: an important strategy to discover new potential S. mansoni vaccine candidates. J Biomed Biotechnol 2011; 2011:503068. [PMID: 22013383 PMCID: PMC3196198 DOI: 10.1155/2011/503068] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 08/12/2011] [Indexed: 11/17/2022] Open
Abstract
The flatworm Schistosoma mansoni is a blood fluke parasite that causes schistosomiasis, a debilitating disease that occurs throughout the developing world. Current schistosomiasis control strategies are mainly based on chemotherapy, but many researchers believe that the best long-term strategy to control schistosomiasis is through immunization with an antischistosomiasis vaccine combined with drug treatment. Several papers on Schistosoma mansoni vaccine and drug development have been published in the past few years, representing an important field of study. The advent of technologies that allow large-scale studies of genes and proteins had a remarkable impact on the screening of new and potential vaccine candidates in schistosomiasis. In this postgenomic scenario, bioinformatic technologies have emerged as important tools to mine transcriptomic, genomic, and proteomic databases. These new perspectives are leading to a new round of rational vaccine development. Herein, we discuss different strategies to identify potential S. mansoni vaccine candidates using computational vaccinology.
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Liu Y, Brindley PJ, Zeng Q, Li Y, Zhou J, Chen Y, Yang S, Zhang Z, Liu B, Cai L, McManus DP. Identification of phage display peptides with affinity for the tegument of Schistosoma japonicum schistosomula. Mol Biochem Parasitol 2011; 180:86-98. [PMID: 21930161 DOI: 10.1016/j.molbiopara.2011.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 08/31/2011] [Accepted: 09/05/2011] [Indexed: 01/06/2023]
Abstract
Peptides, bound to the tegument of live Schistosoma japonicum schistosomula, were differentially screened by phage display in vitro using three rounds of reverse absorption and bio-panning. Three M13 phage peptides were isolated and identified by determination of their recovery rate, immunohistochemical localization, immunoblot analysis, and their anti-schistosomal effects in vivo and in vitro. Of the three, M13 phage peptide ZL4 (MppZL4, YSGLQDSSLRLR, 1.4kDa, pI 8.8) bound to the tegument of mechanically transformed schistosomula and to other developmental stages of S. japonicum from the mammalian host. By contrast, MppZL4 did not bind to the surface of cercariae. To further examine its binding properties, MppZL4 was conjugated to Rhodamine B (RhB-YSGLQDSSLRLR, RhB-ZL4) and a peptide control (RhB-AIPYFSGILQWR, RhB-12P) was similarly synthesized. The binding capacities of RhB-ZL4 to the surface membrane of S. japonicum schistosomula in vitro and of S. japonicum adult worms in vivo were examined and revealed specificity for binding. When examined for anti-parasite activity, both MppZL4 and RhB-ZL4 exhibited a potent schistosomicidal effect in vitro. Further MppZL4 also affected the growth and development of schistosomula in vivo. These findings extend previous studies showing that phage display techniques can recover polypeptides that bind specifically to living schistosomes and, moreover, that these bound peptides have the potential to inhibit key physiological processes in these parasites. Our findings suggest further that ectogenic polypeptides, which can bind to the tegument of S. japonicum, might be adapted as vectors to deliver experimental probes and/or pharmacologically relevant compounds to the schistosome tegument, including drugs and immunological mediators.
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Affiliation(s)
- Yan Liu
- Centre of Cell and Molecular Biology Experiment, Xiangya School of Medicine, Central South University (CSU), 410013 Tongzipo Road 172#, Changsha, Hunan, China
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58
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Abstract
The intravascular trematode Schistosoma mansoni is a causative agent of schistosomiasis, a disease that constitutes a major health problem globally. In this study we cloned and characterized the schistosome tegumental phosphodiesterase SmNPP-5 and evaluated its role in parasite virulence. SmNPP-5 is a 52.5-kDa protein whose gene is rapidly turned on in the intravascular parasitic life stages, following invasion of the definitive host. Highest expression is found in mated adult males. As revealed by immunofluorescence analysis, SmNPP-5 protein is found prominently in the dorsal surface of the tegument of males. Localization by immuno-electron microscopy illustrates a unique pattern of immunogold-labeled SmNPP-5 within the tegument; some immunogold particles are scattered throughout the tissue, but many are clustered in tight arrays. To determine the importance of the protein for the parasites, RNA interference (RNAi) was employed to knock down expression of the SmNPP-5-encoding gene in schistosomula and adult worms. Both quantitative real-time PCR (qRT-PCR) and Western blotting confirmed successful and robust gene suppression. In addition, the suppression and the ectolocalization of this enzyme in live parasites were evident because of a significantly impaired ability of the suppressed parasites to hydrolyze exogenously added phosphodiesterase substrate p-nitrophenyl 5'-dTMP (p-Nph-5'-TMP). The effects of suppressing expression of the SmNPP-5 gene in vivo were tested by injecting parasites into mice. It was found that, unlike controls, parasites whose SmNPP-5 gene was demonstrably suppressed at the time of host infection were greatly impaired in their ability to establish infection. These results demonstrate that SmNPP-5 is a virulence factor for schistosomes.
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59
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Parker-Manuel SJ, Ivens AC, Dillon GP, Wilson RA. Gene expression patterns in larval Schistosoma mansoni associated with infection of the mammalian host. PLoS Negl Trop Dis 2011; 5:e1274. [PMID: 21912711 PMCID: PMC3166049 DOI: 10.1371/journal.pntd.0001274] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 06/28/2011] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The infective schistosome cercaria develops within the intramolluscan daughter sporocyst from an undifferentiated germ ball, during which synthesis of proteins essential for infection occurs. When the aquatic cercaria locates the mammalian host it rapidly penetrates into the epidermis using glandular secretions. It then undergoes metamorphosis into the schistosomulum, including replacement of its tegument surface membranes, a process taking several days before it exits the skin. Patterns of gene expression underlying this transition have been characterised. METHODS AND PRINCIPAL FINDINGS All gene models from the S. mansoni genome (www.GeneDB.org) were incorporated into a high-density oligonucleotide array. Double-stranded cDNA from germ balls, cercariae, and day 3 schistosomula was hybridised to the array without amplification. Statistical analysis was performed using Bioconductor to reveal differentially transcribed loci. Genes were categorised on the basis of biological process, tissue association or molecular function to aid understanding of the complex processes occurring. Genes necessary for DNA replication were enriched only in the germ ball, while those involved in translation were up-regulated in the germ ball and/or day 3 schistosomulum. Different sets of developmental genes were up-regulated at each stage. A large number of genes encoding elastases and invadolysins, and some venom allergen-like proteins were up-regulated in the germ ball, those encoding cysteine and aspartic proteases in the cercaria and schistosomulum. Micro exon genes encoding variant secreted proteins were highly up-regulated in the schistosomulum along with tegument and gut-associated genes, coincident with remodelling of the parasite body. Genes encoding membrane proteins were prominently up-regulated in the cercaria and/or day 3 schistosomulum. CONCLUSIONS/SIGNIFICANCE Our study highlights an expanded number of transcripts encoding proteins potentially involved in skin invasion. It illuminates the process of metamorphosis into the schistosomulum and highlights the very early activation of gut-associated genes whilst revealing little change in the parasite's energy metabolism or stress responses.
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Abstract
Schistosomes (blood flukes) are long lived, intravascular parasites that afflict ~200 million people worldwide. Here we review the potential ability of these parasites to exert control on local vascular physiology. We examine schistosome kallikrein-like proteins that drive vasodilation. We review biogenic amine metabolism in the parasites that involve the vasodilator histamine and its receptors and the vasoconstrictor serotonin and its receptor. Schistosomes can trigger the release of histamine from host cells and can import serotonin. We consider the ability of schistosomes to generate and release the eicosanoid vasodilators PGD(2) and PGE(2) and the vasoconstrictors LTB(4) and LTC(4). The literature on nitric oxide metabolism in these blood flukes is assessed. Finally the potential impact of other schistosome metabolic processes (e.g. exogenous adenosine generation and acetylcholine degradation) on vascular function is appraised. An increased understanding of these processes could lead to novel anti-parasitics as well as new therapies to treat vascular dysfunction.
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Affiliation(s)
- Akram Da’darah
- Molecular Helminthology Laboratory, Division of Infectious Diseases, Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, Grafton, MA 01536, USA
| | - Patrick J. Skelly
- Molecular Helminthology Laboratory, Division of Infectious Diseases, Department of Biomedical Sciences, Cummings School of Veterinary Medicine, Tufts University, Grafton, MA 01536, USA
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Castro-Borges W, Simpson DM, Dowle A, Curwen RS, Thomas-Oates J, Beynon RJ, Wilson RA. Abundance of tegument surface proteins in the human blood fluke Schistosoma mansoni determined by QconCAT proteomics. J Proteomics 2011; 74:1519-33. [PMID: 21704203 DOI: 10.1016/j.jprot.2011.06.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 06/06/2011] [Accepted: 06/12/2011] [Indexed: 12/20/2022]
Abstract
The schistosome tegument provides a major interface with the host blood stream in which it resides. Our recent proteomic studies have identified a range of proteins present in the complex tegument structure, and two models of protective immunity have implicated surface proteins as mediating antigens. We have used the QconCAT technique to evaluate the relative and absolute amounts of tegument proteins identified previously. A concatamer comprising R- or K-terminated peptides was generated with [(13)C(6)] lysine/arginine amino acids. Two tegument surface preparations were each spiked with the purified SmQconCAT as a standard, trypsin digested, and subjected to MALDI ToF-MS. The absolute amounts of protein in the biological samples were determined by comparing the areas under the pairs of peaks, separated by 6m/z units, representing the light and heavy peptides derived from the biological sample and SmQconCAT, respectively. We report that aquaporin is the most abundant transmembrane protein, followed by two phosphohydrolases. Tetraspanin Tsp-2 and Annexin-2 are also abundant but transporters are scarce. Sm200 surface protein comprised the bulk of the GPI-anchored fraction and likely resides in the secreted membranocalyx. Two host IgGs were identified but in amounts much lower than their targets. The findings are interpreted in relation to the models of protective immunity.
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Affiliation(s)
- William Castro-Borges
- Centre for Immunology & Infection, Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
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62
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Wu W, Cai P, Chen Q, Wang H. Identification of novel antigens within the Schistosoma japonicum tetraspanin family based on molecular characterization. Acta Trop 2011; 117:216-24. [PMID: 21237127 DOI: 10.1016/j.actatropica.2011.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 01/06/2023]
Abstract
Tetraspanins (TSPs) are proteins found on the surface of the parasite Schistosoma mansoni that have been regarded as potential protective antigens. However, divergent evolution may occur among the species of S. mansoni and Schistosoma japonicum under different environmental pressure. Thus, it was essential to characterize the S. japonicum TSP family members before selecting potential candidate TSP antigens. In this study, we used bioinformatics and experimental validation to investigate 29 TSP members from S. japonicum, including all known genes, Sj23, TE736, Sj25, and Sj-TSP-2. Five TSP members were found to be variable, and two others (Sj-tsp genes) were alternatively spliced. The phylogenetic analysis showed that schistosome TSPs were highly divergent from those of other phyla. Quantitative RT-PCR revealed that the Sj-tsp genes were differentially transcribed in the developmental stages of cercariae, schistosomula, adult worms, and eggs. Six Sj-tsp genes were significantly up-regulated during the transformation from cercariae to schistosomula. Four Sj-tsp genes, including Sj-tsp-1, Sj-tsp-8, Sj-tsp-14, and Sj-tsp-26 were confirmed as potential protective antigens based on the molecular characterization. RNAi was preformed against the conserved Sj-tsp genes which were highly expressed in schistosomula to explore gene functions. These data will promote the identification of candidate antigens within the TSP family for developing novel vaccines against S. japonicum infections.
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63
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Geadkaew A, von Bülow J, Beitz E, Grams SV, Viyanant V, Grams R. Functional analysis of novel aquaporins from Fasciola gigantica. Mol Biochem Parasitol 2010; 175:144-53. [PMID: 21073907 DOI: 10.1016/j.molbiopara.2010.10.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 10/15/2010] [Accepted: 10/29/2010] [Indexed: 11/17/2022]
Abstract
Fascioliasis, caused by liver flukes of the genus Fasciola, is an important disease of ruminants. In order to identify a potential new drug target we have studied aquaporin (AQP) in Fasciola gigantica. AQPs facilitate the transport of water, glycerol and other small solutes across biological membranes. The structure, function, and pathology of AQPs have been extensively studied in mammals but data for AQPs from trematodes is still limited. In the present study, we have functionally characterized two closely related AQP isoforms, FgAQP-1 and FgAQP-2, from the trematode F. gigantica. Immunohistochemical analysis located the FgAQPs in the tegumental cells, their processes and the tegument itself. In addition, they were present in the epithelial linings of testes and ovary. Expression in Xenopus oocytes of these FgAQPs increased osmotic water permeability 3-4-fold but failed to increase glycerol and urea permeability. AQPs have two highly conserved NPA motifs that are important for the function of the channel pore. In FgAQP-1 and FgAQP-2 the first NPA motif is changed to TAA. Substitution of Thr with Asn in the TAA motif of FgAQP-1 increased its water permeability twofold but did not affect urea and glycerol impermeability while the substitution at the pore mouth of Cys204 by Tyr caused loss of water permeability. In addition, the FgAQPs did not increase methylamine and ammonia permeability after expression in yeast. In comparison to rat AQP-1 the described FgAQPs showed low water permeability and further in vivo analyses are necessary to determine their contribution to osmoregulation in Fasciola.
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Affiliation(s)
- Amornrat Geadkaew
- Faculty of Allied Health Sciences, Thammasat University, Klong Luang, Pathumthani, Thailand
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