Transcriptional analysis of Schistosoma mansoni treated with sub-lethal doses of the anthelmintic drug praziquantel

Schistosoma mansoni is one of the most common etiological agents responsible for the disease schistosomiasis. More than 200 million people suffer from this disease making it the most severe tropical disease after malaria in terms of morbidity. Praziquantel (PZQ) is the treatment of choice for schistosomiasis and has been used almost exclusively to treat the disease since the 1970s. However, while the drug is lethal for sexually mature schistosomes, it is ineffective against juveniles. Thus, while morbidity can be eased, a cure is difficult to achieve. As a result there is an urgent need to develop a new generation of anti-schistosomal drugs, a task that will be made easier by understanding the mechanism of action of PZQ. As yet, neither the molecule to which PZQ binds nor the means by which it kills mature schistosomes is known. The overarching aim of this study was to understand the molecular basis of PZQ sensitivity in S. mansoni. We believe that juvenile worms survive PZQ treatment in vivo due to the induction of, as yet, unidentified protective molecular pathways. To address this hypothesis juvenile and adult PR1 S. mansoni were treated in vitro with sub-lethal concentrations of PZQ. mRNA was extracted from replicate samples, cRNA prepared and labeled with cyanine dyes for analysis using a 44K S. mansoni microarray. The data was then analyzed using Genespring. Our findings suggest that a number of genes associated with drug transport, iron homeostasis and apoptosis are induced in juvenile but not adult schistosomes and that this allows the juvenile worms to protect themselves against the lethal effects of PZQ long enough for the drug to be metabolized by the human host.BiologyMastersUniversity of New Mexico. Biology Dept.Cunningham, CharlesLoker, EricCripps, Richar