Gene suppression in schistosomes using RNAi.

Schistosomiasis is a neglected tropical disease responsible for the death of more than 300,000 people every year. The disease is caused by intravascular parasitic platyhelminths called schistosomes. Treatment and control of schistosomiasis rely on a single drug, praziquantel, and concern exists over the possible emergence of resistance to this drug. The recent completion of the genome sequences of the three main worm species that cause schistosomiasis in humans has raised hope for the development of new interventions to treat the disease. RNA interference (RNAi), a mechanism by which gene-specific double-stranded RNA (dsRNA) triggers degradation of homologous mRNA transcripts, has emerged as an important tool to evaluate and validate new potential drug targets. In addition, RNAi has been used to explore the basic biology of these debilitating parasites. RNAi can be achieved in all stages of the parasite's life cycle in which it has been tested. In this review, we describe methods for applying RNAi to suppress gene expression in the intra-mammalian life stages (adults and schistosomula) of Schistosoma mansoni. We describe procedures for isolating and culturing the parasites, preparing and delivering dsRNA targeting a specific gene, as well as a procedure to evaluate gene suppression by quantitative real-time PCR.