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Tallima H, Mahmoud SS. Mechanisms of Arachidonic Acid In Vitro Schistosomicidal Potential. ACS OMEGA 2024; 9:23316-23328. [PMID: 38854551 PMCID: PMC11154912 DOI: 10.1021/acsomega.3c09906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 03/23/2024] [Accepted: 03/28/2024] [Indexed: 06/11/2024]
Abstract
Arachidonic acid (ARA) was shown to possess safe and effective schistosomicidal impact on larval and adult Schistosoma mansoni and Schistosoma hematobium in vitro and in vivo in laboratory rodents and in children residing in low and high endemicity regions. We herein examine mechanisms underlying ARA schistosomicidal potential over two experiments, using in each pool a minimum of 50 adult male, female, or mixed-sex freshly recovered, ex vivo S. mansoni. Worms incubated in fetal calf serum-free medium were exposed to 0 or 10 mM ARA for 1 h at 37 °C and immediately processed for preparation of surface membrane and whole worm body homogenate extracts. Mixed-sex worms were additionally used for evaluating the impact of ARA exposure on the visualization of outer membrane cholesterol, sphingomyelin (SM), and ceramide in immunofluorescence assays. Following assessment of protein content, extracts of intact and ARA-treated worms were examined and compared for SM content, neutral sphingomyelinase activity, reactive oxygen species levels, and caspase 3/7 activity. Arachidonic acid principally led to perturbation of the organization, integrity, and SM content of the outer membrane of male and female worms and additionally impacted female parasites via stimulating neutral sphingomyelinase activity and oxidative stress. Arachidonic powerful action on female worms combined with its previously documented ovocidal activities supports its use as safe and effective therapy against schistosomiasis, provided implementation of the sorely needed and long waited-for chemical synthesis.
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Affiliation(s)
- Hatem Tallima
- Department
of Chemistry, School of Sciences and Engineering, American University in Cairo, New Cairo, Cairo 11835, Egypt
| | - Soheir S. Mahmoud
- Department
of Parasitology, Theodore Bilharz Research
Institute, Warrak El-Hadar, Imbaba,Giza 12411, Egypt
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Tallima H, Hanna VS, El Ridi R. Arachidonic Acid Is a Safe and Efficacious Schistosomicide, and an Endoschistosomicide in Natural and Experimental Infections, and Cysteine Peptidase Vaccinated Hosts. Front Immunol 2020; 11:609994. [PMID: 33281832 PMCID: PMC7705376 DOI: 10.3389/fimmu.2020.609994] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/26/2020] [Indexed: 12/11/2022] Open
Abstract
Blood flukes of the genus Schistosoma are covered by a protective heptalaminated, double lipid bilayer surface membrane. Large amounts of sphingomyelin (SM) in the outer leaflet form with surrounding water molecules a tight hydrogen bond barrier, which allows entry of nutrients and prevents access of host immune effectors. Excessive hydrolysis of SM to phosphoryl choline and ceramide via activation of the parasite tegument-associated neutral sphingomyelinase (nSMase) with the polyunsaturated fatty acid, arachidonic acid (ARA) leads to parasite death, via allowing exposure of apical membrane antigens to antibody-dependent cell-mediated cytotoxicity (ADCC), and accumulation of the pro-apoptotic ceramide. Surface membrane nSMase represents, thus, a worm Achilles heel, and ARA a valid schistosomicide. Several experiments conducted in vitro using larval, juvenile, and adult Schistosoma mansoni and Schistosoma haematobium documented ARA schistosomicidal potential. Arachidonic acid schistosomicidal action was shown to be safe and efficacious in mice and hamsters infected with S. mansoni and S. haematobium, respectively, and in children with light S. mansoni infection. A combination of praziquantel and ARA led to outstanding cure rates in children with heavy S. mansoni infection. Additionally, ample evidence was obtained for the powerful ARA ovocidal potential in vivo and in vitro against S. mansoni and S. haematobium liver and intestine eggs. Studies documented ARA as an endogenous schistosomicide in the final mammalian and intermediate snail hosts, and in mice and hamsters, immunized with the cysteine peptidase-based vaccine. These findings together support our advocating the nutrient ARA as the safe and efficacious schistosomicide of the future.
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Affiliation(s)
- Hatem Tallima
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt.,Department of Chemistry, School of Science and Engineering, American University in Cairo, New Cairo, Cairo, Egypt
| | - Violette S Hanna
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt
| | - Rashika El Ridi
- Zoology Department, Faculty of Science, Cairo University, Giza, Egypt
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Whiteland H, Crusco A, Bloemberg LW, Tibble-Howlings J, Forde-Thomas J, Coghlan A, Murphy PJ, Hoffmann KF. Quorum sensing N-Acyl homoserine lactones are a new class of anti-schistosomal. PLoS Negl Trop Dis 2020; 14:e0008630. [PMID: 33075069 PMCID: PMC7595621 DOI: 10.1371/journal.pntd.0008630] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/29/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023] Open
Abstract
Background Schistosomiasis is a prevalent neglected tropical disease that affects approximately 300 million people worldwide. Its treatment is through a single class chemotherapy, praziquantel. Concerns surrounding the emergence of praziquantel insensitivity have led to a need for developing novel anthelmintics. Methodology/Principle findings Through evaluating and screening fourteen compounds (initially developed for anti-cancer and anti-viral projects) against Schistosoma mansoni, one of three species responsible for most cases of human schistosomiasis, a racemic N-acyl homoserine (1) demonstrated good efficacy against all intra mammalian lifecycle stages including schistosomula (EC50 = 4.7 μM), juvenile worms (EC50 = 4.3 μM) and adult worms (EC50 = 8.3 μM). To begin exploring structural activity relationships, a further 8 analogues of this compound were generated, including individual (R)- and (S)- enantiomers. Upon anti-schistosomal screening of these analogues, the (R)- enantiomer retained activity, whereas the (S)- lost activity. Furthermore, modification of the lactone ring to a thiolactone ring (3) improved potency against schistosomula (EC50 = 2.1 μM), juvenile worms (EC50 = 0.5 μM) and adult worms (EC50 = 4.8 μM). As the effective racemic parent compound is structurally similar to quorum sensing signaling peptides used by bacteria, further evaluation of its effect (along with its stereoisomers and the thiolactone analogues) against Gram+ (Staphylococcus aureus) and Gram- (Escherichia coli) species was conducted. While some activity was observed against both Gram+ and Gram- bacteria species for the racemic compound 1 (MIC 125 mg/L), the (R) stereoisomer had better activity (125 mg/L) than the (S) (>125mg/L). However, the greatest antimicrobial activity (MIC 31.25 mg/L against S. aureus) was observed for the thiolactone containing analogue (3). Conclusion/Significance To the best of our knowledge, this is the first demonstration that N-Acyl homoserines exhibit anthelmintic activities. Furthermore, their additional action on Gram+ bacteria opens a new avenue for exploring these molecules more broadly as part of future anti-infective initiatives. Schistosomiasis, caused by infection with blood fluke schistosomes, is a neglected tropical disease that negatively impacts the lives of approximately 300 million people worldwide. In the absence of a vaccine, it is currently controlled by a single drug, Praziquantel (PZQ). Although incredibly valuable in controlling disease burden, PZQ-mediated chemotherapy is ineffective against juvenile worms and may not be sustainable should resistance develop. The need to identify an alternative or combinatorial drug is, therefore, a priority in contributing to the control of this parasitic disease into the 21st century. In this study, we have identified a new class of anthelmintic, N-acyl homoserine lactones, which are normally used by bacteria for quorum sensing and population density control. The tested N-acyl homoserine lactones were active against all intra-human schistosome lifecycle stages, in particular, when a thiolactone modification to the core N-acyl homoserine ring was made. Interestingly, these N-acyl homoserine lactones also displayed antimicrobial activities against Gram+Staphylococcus aureus. By demonstrating broad activities against schistosomes and bacteria exemplars, this study identified a potential route for the further development of a new anti-infective class.
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Affiliation(s)
- Helen Whiteland
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, United Kingdom
| | - Alessandra Crusco
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, United Kingdom
| | - Lisa W. Bloemberg
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, United Kingdom
| | | | - Josephine Forde-Thomas
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, United Kingdom
| | - Avril Coghlan
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, United Kingdom
| | - Patrick J. Murphy
- School of Natural Sciences, Bangor University, Gwynedd, United Kingdom
| | - Karl F. Hoffmann
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Aberystwyth, Wales, United Kingdom
- * E-mail:
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El Ridi R, Tallima H, Migliardo F. Biochemical and biophysical methodologies open the road for effective schistosomiasis therapy and vaccination. Biochim Biophys Acta Gen Subj 2016; 1861:3613-3620. [PMID: 27062905 DOI: 10.1016/j.bbagen.2016.03.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 03/19/2016] [Accepted: 03/22/2016] [Indexed: 12/27/2022]
Abstract
BACKGROUND Schistosomiasis caused by blood-dwelling flukes, namely Schistosoma mansoni and Schistosoma haematobium is a severe debilitating disease, widespread in sub-Saharan Africa, the Middle East, and South America. Developing and adult worms are unscathed by the surrounding immune effectors and antibodies because the parasite is protected by a double lipid bilayer armor which allows access of nutrients, while binding of specific antibodies is denied. SCOPE OF REVIEW Fluorescence recovery after bleaching, extraction of surface membrane cholesterol by methyl-β-cyclodextrin, inhibition and activation of sphingomyelin biosynthesis and hydrolysis, and elastic incoherent and quasi-elastic neutron scattering approaches have helped to clarify the basic mechanism of this immune evasion, and showed that sphingomyelin (SM) molecules in the worm apical lipid bilayer form with surrounding water molecules a tight hydrogen bond barrier. Viability of the parasite and permeability of the outer shield are controlled by equilibrium between SM biosynthesis and activity of a tegument-associated neutral sphingomyelinase (nSMase). MAJOR CONCLUSIONS Excessive nSMase activation by polyunsaturated fatty acids (PUFA), such as arachidonic acid (ARA) leads to disruption of the SM molecules and associated hydrogen bond network, with subsequent access of host antibodies and immune effectors to the outer membrane and eventual parasite death. GENERAL SIGNIFICANCE ARA was predicted and shown to be a potent schistosomicide in vitro and in vivo in experimental animals and in children. Additionally, it was advocated that schistosomiasis vaccine candidates should be selected uniquely among excretory-secretory products of developing worms, as contrary to cytosolic and surface membrane antigens, they are able to activate the effector functions of the host antibodies and toxic molecules. This article is part of a Special Issue entitled "Science for Life" Guest Editor: Dr. Austen Angell, Dr. Salvatore Magazù and Dr. Federica Migliardo".
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Affiliation(s)
- Rashika El Ridi
- Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt.
| | - Hatem Tallima
- Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt; Department of Chemistry, School of Science and Engineering, American University in Cairo, New Cairo, 11835 Cairo, Egypt
| | - Federica Migliardo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, 98166 Messina, Italy
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Panic G, Vargas M, Scandale I, Keiser J. Activity Profile of an FDA-Approved Compound Library against Schistosoma mansoni. PLoS Negl Trop Dis 2015; 9:e0003962. [PMID: 26230921 PMCID: PMC4521867 DOI: 10.1371/journal.pntd.0003962] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 07/07/2015] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND As plans to expand mass drug treatment campaigns to fight schistosomiasis form, worries about reliance on praziquantel as the sole available treatment motivate the investigation for novel antischistosomal compounds. Drug repurposing might be an inexpensive and effective source of novel antischistosomal leads. METHODOLOGY 1600 FDA approved compounds were first assayed against Schistosoma mansoni schistosomula at a concentration of 10 µM. Active compounds identified from this screen were advanced to the adult worm screen at 33.33 µM, followed by hit characterization. Leads with complementary pharmacokinetic and toxicity profiles were then selected for in vivo studies. PRINCIPAL FINDINGS The in vitro screen identified 121 and 36 compounds active against the schistosomula and adult stage, respectively. Further, in vitro characterization and comparison with already available pharmacokinetic and toxicity data identified 11 in vivo candidates. Doramectin (10 mg/kg) and clofazimine (400 mg/kg) were found to be active in vivo with worm burden reductions of 60.1% and 82.7%, respectively. CONCLUSIONS/SIGNIFICANCE The work presented here expands the knowledge of antischistosomal properties of already approved compounds and underscores variations observed between target-based and phenotypic approaches and among laboratories. The two in vivo-active drugs identified in this study, doramectin and clofazimine are widely available and present as novel drug classes as starting points for further investigation.
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Affiliation(s)
- Gordana Panic
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Mireille Vargas
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
| | - Ivan Scandale
- Drugs for Neglected Diseases initiative (DNDi), Geneva, Switzerland
| | - Jennifer Keiser
- Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland
- University of Basel, Basel, Switzerland
- * E-mail:
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Gobert GN, You H, McManus DP. Gaining biological perspectives from schistosome genomes. Mol Biochem Parasitol 2014; 196:21-8. [PMID: 25076011 DOI: 10.1016/j.molbiopara.2014.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 07/14/2014] [Accepted: 07/17/2014] [Indexed: 02/06/2023]
Abstract
Characterization of the genomic basis underlying schistosome biology is an important strategy for the development of future treatments and interventions. Genomic sequence is now available for the three major clinically relevant schistosome species, Schistosoma mansoni, S. japonicum and S. haematobium, and this information represents an invaluable resource for the future control of human schistosomiasis. The identification of a biologically important, but distinct from the host, schistosome gene product is the ultimate goal for many research groups. While the initial elucidation of the genome of an organism is critical for most biological research, continued improvement or curation of the genome construction should be an ongoing priority. In this review we will discuss prominent recent findings utilizing a systems approach to schistosome biology, as well as the increased use of interference RNA (RNAi). Both of these research strategies are aiming to place parasite genes into a more meaningful biological perspective.
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Affiliation(s)
- Geoffrey N Gobert
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
| | - Hong You
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
| | - Donald P McManus
- Molecular Parasitology Laboratory, Infectious Diseases Division, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia
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El Ridi R, Tallima H. Vaccine-Induced Protection Against Murine Schistosomiasis Mansoni with Larval Excretory–Secretory Antigens and Papain or Type-2 Cytokines. J Parasitol 2013; 99:194-202. [DOI: 10.1645/ge-3186.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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El Ridi RAF, Tallima HAM. Novel therapeutic and prevention approaches for schistosomiasis: review. J Adv Res 2012; 4:467-78. [PMID: 25685454 PMCID: PMC4293887 DOI: 10.1016/j.jare.2012.05.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 05/12/2012] [Accepted: 05/15/2012] [Indexed: 01/23/2023] Open
Abstract
Schistosomiasis is a debilitating disease affecting approximately 600 million people in 74 developing countries, with 800 million, mostly children at risk. To circumvent the threat of having praziquantel (PZQ) as the only drug used for treatment, several PZQ derivatives were synthesized, and drugs destined for other parasites were used with success. A plethora of plant-derived oils and extracts were found to effectively kill juvenile and adult schistosomes, yet none was progressed to pre- and clinical studies except an oleo-gum resin extracted from the stem of Commiphora molmol, myrrh, which action was challenged in several trials. We have proposed an essential fatty acid, a component of our diet and cells, the polyunsaturated fatty acid arachidonic acid (ARA) as a remedy for schistosomiasis, due to its ability to activate the parasite tegument-bound neutral sphingomyelinase, with subsequent hydrolysis of the apical lipid bilayer sphingomyelin molecules, allowing access of specific antibody molecules, and eventual worm attrition. This concept was convincingly supported using larval and adult Schistosoma mansoni and Schistosoma haematobium worms in in vitro experiments, and in vivo studies in inbred mice and outbred hamsters. Even if ARA proves to be an entirely effective and safe therapy for schistosomiasis, it will not prevent reinfection, and accordingly, the need for developing an effective vaccine remains an urgent priority. Our studies have supported the status of S. mansoni calpain, glutathione-S-transferase, aldolase, triose phosphate isomerase, glyceraldehyde 3-phosphate dehydrogenase, enolase, and 2-cys peroxiredoxin as vaccine candidates, as they are larval excreted-secreted products and, contrary to the surface membrane molecules, are entirely accessible to the host immune system effector elements. We have proposed that the use of these molecules, in conjunction with Th2 cytokines-inducing adjuvants for recruiting and activating eosinophils and basophils, will likely lead to development and implementation of a sterilizing vaccine in a near future.
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Affiliation(s)
- Rashika A F El Ridi
- Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt
| | - Hatem A-M Tallima
- Zoology Department, Faculty of Science, Cairo University, Cairo 12613, Egypt
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Efficacy and mechanism of action of arachidonic acid in the treatment of hamsters infected with Schistosoma mansoni or Schistosoma haematobium. Int J Antimicrob Agents 2012; 39:232-9. [PMID: 22240411 DOI: 10.1016/j.ijantimicag.2011.08.019] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 08/28/2011] [Accepted: 08/30/2011] [Indexed: 01/22/2023]
Abstract
We have recently shown that in vitro and in vivo exposure of Schistosoma mansoni and Schistosoma haematobium to 5-10mM arachidonic acid (ARA) induces parasite surface membrane disintegration and eventual attrition. Here we report on the optimum ARA dose and post-infection treatment time for maximum schistosome demise in hamsters. A series of four experiments for each schistosome species indicated that oral administration of ARA after patency led to a highly significant (P<0.02 to <0.001) reduction in worm burden accompanied by a significant (P<0.05) decrease in worm egg load. ARA-mediated attrition in vivo appeared to be associated with high titres of serum antibodies to tegumental antigens. In support, serum antibodies from patently infected and ARA-treated hamsters readily bound to the surface membrane of ARA-exposed adult worms, as judged by indirect membrane immunofluorescence. More importantly, addition of serum antibodies and peripheral blood mononuclear cells significantly enhanced ARA-mediated adult worm attrition in vitro. These data together show that the schistosomicidal effect of ARA in laboratory animals is enhanced by immune effectors and is highly efficacious and entirely safe.
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Enzymatic activity and immunolocalization of Schistosoma mansoni and Schistosoma haematobium neutral sphingomyelinase. Mol Biochem Parasitol 2011; 178:23-8. [PMID: 21524668 DOI: 10.1016/j.molbiopara.2011.04.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2011] [Revised: 04/04/2011] [Accepted: 04/06/2011] [Indexed: 11/22/2022]
Abstract
We predicted, and provided evidence for, the existence of a schistosome tegument-associated Mg(2+)-dependent neutral sphingomyelinase (nSMase), which controls hydrolysis of surface membrane sphingomyelin molecules, thus allowing nutrients, but not host antibodies, to access proteins at the host-parasite interface. While a putative nSMase was identified in a recent Schistosoma mansoni genome sequencing and analysis study, our report is the first to measure nSMase enzymatic activity in Triton X-100-solubilized surface membrane (Sup 1) and whole worm soluble (SWAP) molecules of male and female S. mansoni and Schistosoma haematobium. Neutral, but no acidic, sphingomyelinase activity was readily detectable by the amplex red sphingomyelinase assay, and increased with incubation time and protein amount. Like nSMase family members, the schistosome nSMase activity was significantly (P<0.05 to <0.0001) enhanced by unsaturated fatty acids and phosphatidyl serine and significantly (P<0.01) decreased following exposure to the nSMase specific inhibitor GW4869. Peptides based on the published sequence of S. mansoni putative nSMase and used in a multiple antigen peptide form induced the generation of specific antibodies, which readily bound to the immunogen and to the cognate protein in Sup 1 and SWAP. Immunofluorescence studies suggested the parasite nSMase is located in the worm tegument and gut lining. Studies using RNA interference are in progress to define nSMase role in larval and adult worm surface membrane antigen exposure and unsaturated fatty acid-mediated attrition.
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Tallima H, El Ridi R. Schistosoma mansoni glyceraldehyde 3-phosphate dehydrogenase is a lung-stage schistosomula surface membrane antigen. Folia Parasitol (Praha) 2008; 55:180-6. [DOI: 10.14411/fp.2008.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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