Suppression of mRNAs encoding tegument tetraspanins from Schistosoma mansoni results in impaired tegument turnover.
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.
Tran
Mai H
MH
Division of Infectious Diseases, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
Freitas
Tori C
TC
Cooper
Leanne
L
Gaze
Soraya
S
Gatton
Michelle L
ML
Jones
Malcolm K
MK
Lovas
Erica
E
Pearce
Edward J
EJ
Loukas
Alex
A
D000818:Animals; D015153:Blotting, Western; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D017238:Genes, Helminth; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D046529:Microscopy, Electron, Transmission; D034622:RNA Interference; D012333:RNA, Messenger; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012550:Schistosoma mansoni / Q000235:genetics* / Q000378:metabolism* / Q000648:ultrastructure; D012555:Schistosomiasis mansoni / Q000235:genetics*
D015801:Helminth Proteins; D008565:Membrane Proteins; D012333:RNA, Messenger