I-Corps: A C. elegans model using human genes for high-throughput screening

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The broader impact/commercial potential of this I-Corps project is in the improvement of drug discovery. Pharmaceutical companies screen millions of compounds before a single agent is selected to undergo human clinical trials. Initial screening of potential therapeutics is conducted in cell culture assays that allow for low-cost evaluation, but are limited in determining therapeutic relevance. This limitation is overcome by additional screening in multiple mammalian models where potential compounds are further assessed for their therapeutic effects, toxicology etc. Yet, the expenses and time associated with mammalian model testing means that only a small percentage of compounds that pass cellculture screening will make it to this stage, effectively overlooking thousands of compounds that may be potent therapeutics. This project?s technology aims at bypassing this bottleneck. It is labor friendly and cost-effective but at the same time will enable companies to test compounds efficacy on an animal model rather than cells in culture thus allowing for further informed decision making in regards to the development of their compounds.This I-Corps project offers an innovative method to screen compounds targeting the actin cytoskeleton and its associated genes. C. elegans worms are engineered to replace a cytoskeletal gene, OSG-1, with its human homolog, (ARHGEF10), and worms lacking OSG-1, (OSG-1 KO), are maintained in 96-well plates each containing a different compound. Worms are subjected to a 4-hr heat shock and scored for survival. Because the mortality of OSG-1 KO worms is significantly higher than ARHGEF10, only compounds that target the actin cytoskeleton pathway can differentially change the mortality rates of the KO compared to the ARHGEF10 worm. Compounds that are efficacious but affect the mortality rates of the KO and the ARHGEF10 worm to the same extent do not impinge on the actin cytoskeleton pathway (they represent a second cut because they might act on pathways and mechanisms that are not conserved in humans). Worms are engineered to express GFP through most of the body. Only living worms express GFP whereas dead ones do not. Survival assessment only requires scoring fluorescent worms. With costs only accruing from agar and plate costs, early compounds can be screened for potency at a fraction of the cost of traditional early phase drug discovery methods.