Post-genomic studies on the neuropeptide signalling system of Juvenile Fasciola hepatica

Abstract

The flatworm Fasciola hepatica is a globally significant parasite in terms of agricultural productivity and human health. This thesis investigated the role of the neuropeptide signalling system in the biology of this species. Advances in genomic and transcriptomic resources facilitated the identification of a further 20 novel, putative neuropeptide-encoding transcripts in F. hepatica, building on the 15 that had been previously discovered. RNA-sequencing studies from a variety of flatworms were analysed in order to inform hypotheses on neuropeptide functions. These studies have also been used to identify muscle-specific G-Protein Coupled Receptors (GPCRs). These transcripts were taken forward into a larger-scale RNA interference (RNAi) screen which revealed a high level of transcript knockdown and a profound growth phenotype for one member of the Neuropeptide-F/Y-like (NPF/Y) family. Profound motility and growth phenotypes were seen as a result of knocking down neuropeptide processing enzymes. The NPF/Y signalling pathway was further probed with RNAi which supported the role of this pathway in growth and development. An NPF-specific antiserum was used to monitor the development of the nervous system in various juvenile stages of F. hepatica. Combining this staining with the localisation of proliferating cells, or neoblasts, supports a potential link between NPF signalling and neoblasts. Significant improvements have been made to an existing chromogenic in situ hybridization (CISH) protocol to include a more sensitive fluorescent version. Overall, through targeting 45 transcripts using RNAi among other methods, this project has revealed the complexity and importance of the neuropeptide signalling pathway in liver fluke and provides a foundation for more focussed studies on drug target discovery and validation.

Date of Award	Dec 2020
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Northern Ireland Department for the Economy
Supervisor	Nikki Marks (Supervisor) & Aaron Maule (Supervisor)