Fascioliasis is a parasitic disease of significant impact to the global food industry where it is particularly problematic in ruminant lifestock species. It has also been recognised by the WHO as a re-emerging human disease, affecting as many as 2.6 million individuals annually. Fasciola hepatica is the main agent responsible for fascioliasis in temperate climates. Infection is characterised by acute mechanical damage to the host due to migratory juveniles and obstructive as well as chronic inflammatory cholangitis that develops as a consequence of adult maturation in the bile ducts. Treatment is primarily mediated through chemotherapeutics, specifically triclabendazole (TCBZ), the only anthelmintic active against both the juvenile and adult stages. With concern surrounding the development of TCBZ resistance, research towards alternative chemotherapies is urgently required. Recently, epigenetic processes that affect histone post-translational modifications have been identified as a key area of exploration due to their likely considerable role in regulating the parasite’s lifecycle. In this study, 64 histone modification inhibitors were used for in-vitro screening of F. hepatica newly excysted juveniles (NEJs). Of these, three (GSK-J4, NVS-CECR2-1 and LLY507) were determined to have significant effects on both phenotype and motility metrics. Fluorescence microscopy identified a putative shared mechanism of muscular disruption and dissociation of muscle fibres into myocytes. Further bioinformatic characterisation of both histone methylation and acetylation machineries identified putative targets for two of the hits (KDM6A for GSK-J4 and SMYD family for LLY507) as well as new drug candidates. Finally, to improve on gold standard qualitative scoring methodologies, computer vision models were built using convolutional neural networks to automate the segmentation and phenotyping of NEJs during in-vitro culture experiments. This study reveals the importance of F. hepatica histone modifications and provides the foundations for the development of high-throughput drug screening methodologies.
Repositioning histone modifying enzyme (HME) inhibitors as next-generation flukicides
Davey, S. (Awdur). 2024
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