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Suppressing Glucose Transporter Gene Expression in Schistosomes Impairs Parasite Feeding and Decreases Survival in the Mammalian Host

By Greice Krautz-Peterson, Mariana Simoes, Zahra Faghiri, David Ndegwa, Guilherme Oliveira, Charles B. Shoemaker and Patrick J. Skelly


Adult schistosomes live in the host's bloodstream where they import nutrients such as glucose across their body surface (the tegument). The parasite tegument is an unusual structure since it is enclosed not by the typical one but by two closely apposed lipid bilayers. Within the tegument two glucose importing proteins have been identified; these are schistosome glucose transporter (SGTP) 1 and 4. SGTP4 is present in the host interactive, apical tegumental membranes, while SGTP1 is found in the tegumental basal membrane (as well as in internal tissues). The SGTPs act by facilitated diffusion. To examine the importance of these proteins for the parasites, RNAi was employed to knock down expression of both SGTP genes in the schistosomula and adult worm life stages. Both qRT-PCR and western blotting analysis confirmed successful gene suppression. It was found that SGTP1 or SGTP4-suppressed parasites exhibit an impaired ability to import glucose compared to control worms. In addition, parasites with both SGTP1 and SGTP4 simultaneously suppressed showed a further reduction in capacity to import glucose compared to parasites with a single suppressed SGTP gene. Despite this debility, all suppressed parasites exhibited no phenotypic distinction compared to controls when cultured in rich medium. Following prolonged incubation in glucose-depleted medium however, significantly fewer SGTP-suppressed parasites survived. Finally, SGTP-suppressed parasites showed decreased viability in vivo following infection of experimental animals. These findings provide direct evidence for the importance of SGTP1 and SGTP4 for schistosomes in importing exogenous glucose and show that these proteins are important for normal parasite development in the mammalian host

Topics: Research Article
Publisher: Public Library of Science
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Provided by: PubMed Central

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  3. (1975). Anatomical localization of glucose uptake by Schistosoma mansoni adults.
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  5. (1994). Cloning, characterization and functional expression of cDNAs encoding glucose transporter proteins from the human parasite, Schistosoma mansoni.
  6. (1981). Cultivation of Schistosoma mansoni in vitro. I. Establishment of cultures from cercariae and development until pairing.
  7. (2005). Effect of antisense-SGTPs on the glucose uptake of the blood fluke Schistosoma mansoni: observations in adult worms and schistosomula.
  8. (1998). Glucose transport and metabolism in mammalian stage schistosomes.
  9. (1995). Immunolocalization of a Schistosoma mansoni facilitated diffusion glucose transporter to the basal, but not the apical, membranes of the surface syncytium.
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  14. (1996). Rapid appearance and asymmetric distribution of glucose transporter SGTP4 at the apical surface of intramammalian-stage Schistosoma mansoni.
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  16. (2009). RNA interference targeting leucine aminopeptidase blocks hatching of Schistosoma mansoni eggs.
  17. (1996). Schistosoma mansoni:t h e glucose transport protein SGTP4 is present in tegumental multilamellar bodies, discoid bodies, and the surface lipid bilayers.
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  20. (2009). The role of tegumental aquaporin from the human parasitic worm, Schistosoma mansoni, in osmoregulation and drug uptake.
  21. (1967). The sites of (1–14C) glucose assimilation in Schistosoma haematobium.
  22. (1968). Threadgold LT
  23. (2003). Using RNA interference to manipulate endogenous gene expression in Schistosoma mansoni sporocysts.