Development of a high-throughput behavioural assay in Caenorhabditis elegans

Abstract

The global burden of neurological and psychiatric disorders on healthcare and long-term care is large and steadily increasing. Reductionist target-based screening and synthetic chemistry efforts are failing to introduce new drugs into the clinic—a reflection of their failure to capture the complexities of human neurobiology. Medicines derived from natural products have unmatched structural and functional diversity, refined over millions of years of evolutionary trial-and-error. While fungi have seen therapeutic use across human history in traditional medicines, in modern drug discovery these microbes are relatively underexplored. We have assembled a fractionated fungal extract library, with fungi foraged largely from a remote and temperate rainforest off the coast of British Columbia. I present the development of a high-throughput behavioural assay with the model organism C. elegans that will be used to screen this library for the purposes of novel neuroactive drug discovery. I used a custom-designed instrument, the Kastl-HighRes imaging system, to enable the simultaneous capture of high-resolution videos of C. elegans N2 within a standard microwell plate. Behavioural responses were quantified using Tierpsy Tracker, an open-source software that tracks individual and multi-worm behavioural phenotypes such as swimming dynamics, morphology, and trajectory. In this study, I investigate the reproducibility of the data collected using my protocol and I validate my assay by confirming published behavioural phenotypes of three chemicals. I also demonstrate that my assay is sensitive enough to identify neuroactive fungal extracts by characterizing the behavioural phenotype of an uncharacterized fungal metabolite.