Authors
D J Wells1; P McVeigh1; E McCammick1; P McCusker1; E Robb1; M P Evans1; E Gardiner1; A Mousley1; N J Marks1; A G Maule1; 1 Queen's University Belfast, UK Discussion
Increasing resistance to existing flukicides continues to compromise the sustainable control of liver fluke. New flukicides are needed to suppress the impact of fluke infections in animals and humans. G-protein coupled receptors (GPCRs) are established targets for drugs used in human medicine. Within the GPCR complement of the liver fluke, Fasciola hepatica, at least 47 are putative peptide receptors with many of the associated ligands likely to be neuropeptides (npps). Neuropeptidergic-signalling systems are evolutionarily ancient and have been shown to play key roles in a variety of fundamental processes including motility, reproduction and development. Here we report the in silico discovery of the putative npp gene complement of F. hepatica. Thus far, we have identified 37 putative npp genes by using a combination of degenerative search strings involving common npp motifs as well as using reciprocal BLAST searches using previously identified putative npp genes as queries against genomic and transcriptomic datasets. Using the 'new Tuxedo' package (HISAT2, Stringtie and Ballgown), we have assessed the expression of these genes across the intra-mammalian life stages. Further, we have optimised a planarian wholemount in situ protocol for F. hepatica and used it to examine the spatial expression patterns of putative neuropeptide-F/Y-like gene transcripts. We show that these have distinct expression patterns suggesting differential functions. Expression and localisation information will be used to underpin functional genomics approaches such as RNA interference (RNAi) to generate functional data and, where possible, ligand-receptor pairings. These will provide impetus to anthelmintic/flukicide discovery efforts. 
