A Genetic Platform for Functionally Profiling Odorant Receptors Ex Vivo Using Olfactory Cilia

Abstract

AbstractThe molecular basis for odor perception in humans remains a black box as odorant receptors (ORs) are notoriously difficult to study outside of their native environment. Efforts toward OR expression and functional profiling in heterologous systems have been met with limited success due to poor efficiency of cell surface expression and consequently reduced G-protein signal amplification. We previously reported a genetic strategy in mice to increase the number of sensory neurons expressing specific ORs, which transforms the 10 million neurons of the mouse nose into a bioreactor producing large quantities of fully functional OR protein. We now describe the isolation of cilia from these bioreactors for two human ORs. Cilia are known to contain all components of the olfactory signal transduction machinery and can be placed into an ex vivo well-plate assay to rapidly measure robust, reproducible odor-specific responses. Our OR1A1 and OR5AN1 isolated cilia reveal 10-100fold more sensitivity than existing assays. Tissue from a single animal produces up to 4,000 384-well assay wells, and isolated olfactory cilia can be stored frozen and thus preserved for long term usage. This pipeline offers a sensitive, highly scalable ex vivo odor screening platform that opens the door for decoding human olfaction.One Sentence Summaryolfactory-cilia based odor screening platform.