Treatment with the MDR transporter siRNAs significantly reduced egg production by 60%, but no significant switch in egg production was found out for worms electroporated with luciferase siRNA or H2O. , , while males communicate higher SmMRP1 RNA levels than females . Notably, adults upregulate manifestation of both of these transporters in response to PZQ , . Furthermore, higher basal levels of both SMDR2 and SmMRP1 correlate with reduced PZQ susceptibility , , and PZQ inhibits, and is also a likely substrate of, SMDR2 . Based on these findings, we have hypothesized that schistosome MDR Amyloid b-Peptide (10-20) (human) transporters may be modulating the responsiveness of parasites to PZQ . We also predict that schistosome multidrug transporters play crucial functions in worm physiology, development, and perhaps in modifying host responses. In this report, we use genetic and pharmacological approaches to Amyloid b-Peptide (10-20) (human) examine the effects on schistosomes of interference with normal MDR transporter function. We find that knockdown of SMDR2 or SmMRP1 expression in adult worms, or exposure of parasites to pharmacological inhibitors of these transporters, disrupts egg production in cultured adults We used FRAP2 electroporation of Amyloid b-Peptide (10-20) (human) SMDR2 and SmMRP1 siRNAs to knock down expression of the multidrug resistance proteins SMDR2 and SmMRP1 in adult worms. As shown in Fig. 1, electroporation of adult parasites with siRNA targeted against either sequence results in substantial reduction of the relative expression level of that gene, both at the RNA and protein levels. Levels of RNA expression for both genes in pooled adult schistosomes are reduced by 50C70% compared to controls. Addition of SmMRP1 siRNA to the SMDR2 siRNA does not appear to affect RNA levels of SMDR2, nor does addition of SMDR2 siRNA appear to additionally decrease levels of SmMRP1 RNA. Protein expression, as measured by immunoblotting with anti-Pgp and anti-MRP1 antibodies, is also reduced. Open in a separate windows Physique 1 Knockdown of SMDR2 and SmMRP1 expression in adult parasites. Adult parasites were perfused at 6C7 weeks post contamination and electroporated with 3 g of siRNAs or water. Following electroporation, pooled adult worms (males and females) were incubated as described in Materials and Methods, and the expression of SMDR2 and SmMRP1 analyzed for changes in RNA and protein abundance (A, B). Western blot analysis of anti-Pgp (A) or anti-MRP1 (B) cross-reactive proteins (upper panel) isolated from worms treated with SMDR2 siRNA (A, lane 2), SmMRP1 siRNA (B, lane 2), or water (Control, lane 1). Note the decrease in immunoreactivity for both target sequences. Anti–tubulin was used as a loading control. (C, D) Relative expression of SMDR2 (n?=?6C7) or SmMRP1 (n?=?3C4) RNA in adult worms treated with water (H2O, white bars), luciferase siRNA (grey bars), SMDR2 siRNA or SmMRP1 siRNA (black bars), or both SMDR2 and SmMRP1 (hatched bars). SMDR2 and SmMRP1 siRNAs efficiently knock down the mRNA expression levels of SMDR2 by 50% and SmMRP1 by 70%, respectively. The fold changes were determined by quantitative RT-PCR using 18S RNA as the reference gene. *, ** indicate P 0.05 and P 0.01, respectively, compared to the water control, ANOVA. Knockdown of SMDR2 or SmMRP1 decreases egg production in adults Adult schistosomes perfused from the murine host and maintained will continue to produce eggs, though only those deposited during the first 48 h following perfusion from the host appear to be viable . We compared the cumulative number of eggs produced by worms over a 2C3-day span following electroporation with siRNA against SMDR2 or SmMRP1 (or both). We also counted eggs produced by control worms electroporated with luciferase siRNA or with no treatment. As shown in Fig. 2, knockdown of either MDR transporter gene (or both) resulted in a significant reduction in cumulative egg production compared to controls. Open in a separate windows Physique 2 Knockdown of SMDR2 or SmMRP1 in adult schistosomes disrupts parasite egg production.Adult schistosomes were electroporated with H2O or 3 g siRNAs and incubated in RPMI medium Amyloid b-Peptide (10-20) (human) for 48 h. Following electroporation, 2C3 adult pairs (n?=?4C7) were cultured in 16-well plates for 4C5 days and the number of eggs counted. RNAi treatments were luciferase siRNA (grey bar), SmMRP1 siRNA (black bar), SMDR2 siRNA (hatched bar), or both SmMRP1 and SMDR2 siRNA (dotted Amyloid b-Peptide (10-20) (human) bar). Egg counts within each experiment were normalized to the corresponding worms treated with H2O (white bar). Treatment with the MDR transporter.