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

No increased chromosomal damage in L-DOPA-treated patients with Parkinson's disease: a pilot study

Parkinson's disease (PD) is a neurodegenerative movement disorder affecting about 2% of the human population in old age. L-3,4-Dihydroxyphenylalanine (L-DOPA) in combination with a peripheral aromatic amino acid decarboxylase inhibition has been the most frequently prescribed drug for alleviating symptoms of PD, but a potential contribution of L-DOPA therapy to further neurodegeneration via oxidative stress is still debated. We report that the specific oxidative stress biomarker 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) level in peripheral blood lymphocyte DNA was elevated to 8.1 +/- 1.7 8-oxodG/10(6)dG in 17 chronically L-DOPA-treated PD patients, compared to 4.6 +/- 1.2 8-oxodG/10(6)dG in 12 controls. However, the total antioxidative capacity of plasma was increased to 1113 +/- 237 microM in the PD patients compared to 941 +/- 254 microM in controls. The frequency of micronuclei, a subgroup of chromosomal aberrations, in peripheral blood lymphocytes was not elevated compared to healthy age-matched individuals. In vitro, in a cell-free assay, dopamine and its precursor L-DOPA exhibited antioxidative capacity. On the other hand, the 8-oxodG concentration in cultured PC 12 cells was enhanced after dopamine treatment. This elevation may be below a threshold for manifestation as chromosomal damage