GSE120682
Transcriptomic analysis of reduced sensitivity to praziquantel in Schistosoma mansoni
Schistosomiasis is a chronic neglected tropical disease caused by digenetic parasitic flatworms of the genus Schistosoma. The disease is estimated to affect over 206 million people, the majority of whom live in Africa where Schistosoma mansoni and Schistosoma japonicum are the major causative agents. While a number of drugs have been used to treat schistosomiasis, praziquantel (PZQ) is the only one that is widely available, relatively cheap, and easy to use. The reliance on a single drug for the treatment of such a prevalent disease is a cause for concern due to the potential for resistance to render PZQ ineffective. In this study we examine the transcriptome of three generations of a laboratory strain of S. mansoni (PR1) whose susceptibility to PZQ has been diminished across 9 passages through exposure to increasing sub-lethal doses of the drug. Miracidial susceptibility was significantly reduced after exposure to 2 x 50 mg/Kg PZQ during the first passage. Susceptibility of worms in vivo was first assessed during passage 5 when mice infected with PZQ-selected schistosomes were dosed with a lethal dose of 3 x 300 mg/Kg PZQ resulting in only a 10% reduction in worm number compared to control treatment. The emergence of reduced sensitivity was marked by a shift in sex ratio from a predominantly male to female population, a reduction in the length of females and ultimately the loss of the PZQ-selected line after passage 9, perhaps due to a selection induced fitness cost. Analysis of differentially regulated transcripts did not suggest that any particular gene product or pathway was associated with drug resistance suggesting either a loss of function mutation to a single gene or an epistatic interaction of multiple gene products. Overall design: Examination of  lab selected PZQ resistant Schistosoma mansoni parasites, in quadruplicate, through 3 passages using Illumina NextSeq 500.