A major problem in chemical countermeasure discovery is the potential emergence of novel agents forwhich there are no known antidotes or post exposure therapies. Classic countermeasures have often beendiscovered only serendipitously or have taken years to develop. As novel chemical threats emerge (in theform of novel chemical warfare agents or environmental pollutants), the speed with which we are able tounderstand and counteract each threat will determine the magnitude of its societal impact. One promisingapproach for rapidly identifying and manipulating the molecular pathways underlying the response to anychemical threat is the use of phenotype-based chemical screens. Models can be developed in which specifictoxicants result in reproducible phenotypes in cells or whole organisms. By subjecting these models to high-throughput screening (HTS), small molecules could be identified that reverse the phenotype through avariety of novel mechanisms. Small molecules discovered by these screens would be excellent leadcompounds for novel countermeasures and powerful tools for dissecting toxicity pathways, which may in turnpoint to additional countermeasure targets.In this application, we outline a process for rapid development of in vivo organophosphate toxicity modelsand their use in discovery of novel organophosphate countermeasures. Although we expect the proposedproject will lead directly to development of novel organophosphate countermeasures, we also expect it toserve as a model for rapid countermeasure development that can be applied broadly to other existing andemerging chemical threats. Specifically, we propose:
Aim 1. To develop and validate in vivo assays for organophosphate toxicity in the zebrafishWe will seek to identify physiological responses that are surrogates for known human responses toorganophosphates and that can be scaled for high throughput in vivo screening.
Aim 2. To scale these novel assays for automated high-throughput screening in multiwell platesWe will develop assays for organophosphate toxicity that can be performed automatically in 96-well format.
Aim 3. To identify novel compounds that counteract the effects of prior organophosphate exposureHigh-throughput screening will identify compounds that facilitate recovery from organophosphate exposure.
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| Jin, Shan; Sarkar, Kumar S; Jin, Youngnam N et al. (2013) An in vivo zebrafish screen identifies organophosphate antidotes with diverse mechanisms of action. J Biomol Screen 18:108-15 |
| van Ham, Tjakko J; Kokel, David; Peterson, Randall T (2012) Apoptotic cells are cleared by directional migration and elmo1- dependent macrophage engulfment. Curr Biol 22:830-6 |
| Peterson, Randall T; Macrae, Calum A (2012) Systematic approaches to toxicology in the zebrafish. Annu Rev Pharmacol Toxicol 52:433-53 |
| Kokel, David; Bryan, Jennifer; Laggner, Christian et al. (2010) Rapid behavior-based identification of neuroactive small molecules in the zebrafish. Nat Chem Biol 6:231-237 |
| van Ham, Tjakko J; Mapes, James; Kokel, David et al. (2010) Live imaging of apoptotic cells in zebrafish. FASEB J 24:4336-42 |
