Tetrahydrofuran-Based Transient Receptor Potential Ankyrin 1 (TRPA1) Antagonists: Ligand-Based Discovery, Activity in a Rodent Asthma Model, and Mechanism-of-Action via Cryogenic Electron Microscopy.
Terrett JA, Chen H, Shore DG, Villemure E, Larouche-Gauthier R, Déry M, Beaumier F, Constantineau-Forget L, Grand-Maître C, Lépissier L, Ciblat S, Sturino C, Chen Y, Hu B, Lu A, Wang Y, Cridland AP, Ward SI, Hackos DH, Reese RM, Shields SD, Chen J, Balestrini A, Riol-Blanco L, Lee WP, Liu J, Suto E, Wu X, Zhang J, Ly JQ, La H, Johnson K, Baumgardner M, Chou KJ, Rohou A, Rougé L, Safina BS, Magnuson S, Volgraf M.
Transient receptor potential ankyrin 1 (TRPA1) is a nonselective calcium-permeable ion channel highly expressed in the primary sensory neurons functioning as a polymodal sensor for exogenous and endogenous stimuli and has generated widespread interest as a target for inhibition due to its implication in neuropathic pain and respiratory disease. Herein, we describe the optimization of a series of potent, selective, and orally bioavailable TRPA1 small molecule antagonists, leading to the discovery of a novel tetrahydrofuran-based linker. Given the balance of physicochemical properties and strong <i>in vivo</i> target engagement in a rat AITC-induced pain assay, compound <b>20</b> was progressed into a guinea pig ovalbumin asthma model where it exhibited significant dose-dependent reduction of inflammatory response. Furthermore, the structure of the TRPA1 channel bound to compound <b>21</b> was determined via cryogenic electron microscopy to a resolution of 3 Å, revealing the binding site and mechanism of action for this class of antagonists.