Characterising the complexity of endocannabinoid signalling pathways in parasitic helminths

In addition, understanding of flatworm ECS pathways is sparse, with only a handful of studies demonstrating the presence of EC ligands and associated-pathway enzymes however, the complexity and conservation of the flatworm ECS system remains almost entirely uncharacterised. This study: (a) employed an in silico bioinformatics pipeline to examine the conservation, expression and phylogenetic relationships of EC-effectors in phylum Nematoda and phylum Platyhelminthes; (b) translated in situ hybridisation approaches to the model animal parasitic nematodes Strongyloides ratti and Strongyloides stercoralis to facilitate future EC-effector localisation efforts and, (c) exploited CRISPR/cas-9 mediated genome editing in S. stercoralis for mutagenesis of the putative EC-GPCR npr-19.

These studies demonstrate that (i) helminth ECS pathways exhibit increased complexity in comparison to vertebrate ECS pathways; (ii) EC-effectors exhibit broad pan-phylum conservation in nematodes and flatworms; (iii) flatworms encode a novel, putative, cannabinoid-like receptor denoted here as FwCB1/2; (iv) EC-effectors are expressed in therapeutically relevant helminth life stages, including infective larvae, suggesting that ECS pathways may be involved in key parasite behaviours; (v) EC-GPCR knockout mutants are achievable in S. stercoralis via CRISPR-mediated targeted mutagenesis.

Collectively, these data advance our understanding of ECS pathway complexity in helminths and will inform the identification and validation of putative novel drug targets in parasitic helminths.<br><br><br>