Suppression of mRNAs encoding tegument tetraspanins from Schistosoma mansoni results in impaired tegument turnover

• Published in: PLoS pathogens Vol. 6; no. 4; p. e1000840
• Main Authors: Tran, Mai H, Freitas, Tori C, Cooper, Leanne, Gaze, Soraya, Gatton, Michelle L, Jones, Malcolm K, Lovas, Erica, Pearce, Edward J, Loukas, Alex
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 15.04.2010; Public Library of Science (PLoS)
• Subjects: Animals; Biomedical research; Blotting, Western; Fluorescent Antibody Technique; Gene Expression; Genes, Helminth; Helminth Proteins - genetics; Helminth Proteins - metabolism; Infectious Diseases/Helminth Infections; Membrane Proteins - genetics; Membrane Proteins - metabolism; Membranes; Mice; Microscopy; Microscopy, Electron, Transmission; Parasites; Parasitic diseases; Proteins; Reverse Transcriptase Polymerase Chain Reaction; RNA Interference; RNA, Messenger; Schistosoma mansoni - genetics; Schistosoma mansoni - metabolism; Schistosoma mansoni - ultrastructure; Schistosomiasis mansoni - genetics; Scholarships & fellowships; Tropical diseases; Vaccines; Worms
• ISSN: 1553-7374; 1553-7366; 1553-7374
• DOI: 10.1371/journal.ppat.1000840

Schistosomes express a family of integral membrane proteins, called tetraspanins (TSPs), in the outer surface membranes of the tegument. Two of these tetraspanins, Sm-TSP-1 and Sm-TSP-2, confer protection as vaccines in mice, and individuals who are naturally resistant to S. mansoni infection mount a strong IgG response to Sm-TSP-2. To determine their functions in the tegument of S. mansoni we used RNA interference to silence expression of Sm-tsp-1 and Sm-tsp-2 mRNAs. Soaking of parasites in Sm-tsp dsRNAs resulted in 61% (p = 0.009) and 74% (p = 0.009) reductions in Sm-tsp-1 and Sm-tsp-2 transcription levels, respectively, in adult worms, and 67%-75% (p = 0.011) and 69%-89% (p = 0.004) reductions in Sm-tsp-1 and Sm-tsp-2 transcription levels, respectively, in schistosomula compared to worms treated with irrelevant control (luciferase) dsRNA. Ultrastructural morphology of adult worms treated in vitro with Sm-tsp-2 dsRNA displayed a distinctly vacuolated and thinner tegument compared with controls. Schistosomula exposed in vitro to Sm-tsp-2 dsRNA had a significantly thinner and more vacuolated tegument, and morphology consistent with a failure of tegumentary invaginations to close. Injection of mice with schistosomula that had been electroporated with Sm-tsp-1 and Sm-tsp-2 dsRNAs resulted in 61% (p = 0.005) and 83% (p = 0.002) reductions in the numbers of parasites recovered from the mesenteries four weeks later when compared to dsRNA-treated controls. These results imply that tetraspanins play important structural roles impacting tegument development, maturation or stability.