title: Discovery of a potent and selective α3β4 nicotinic acetylcholine receptor antagonist from an α-conotoxin synthetic combinatorial library.
abstract: α-Conotoxins are disulfide-rich peptide neurotoxins that selectively inhibit neuronal nicotinic acetylcholine receptors (nAChRs). The α3β4 nAChR subtype has been identified as a novel target for managing nicotine addiction. Using a mixture-based positional-scanning synthetic combinatorial library (PS-SCL) with the α4/4-conotoxin BuIA framework, we discovered a highly potent and selective α3β4 nAChR antagonist. The initial PS-SCL consisted of a total of 113 379 904 sequences that were screened for α3β4 nAChR inhibition, which facilitated the design and synthesis of a second generation library of 64 individual α-conotoxin derivatives. Eleven analogues were identified as α3β4 nAChR antagonists, with TP-2212-59 exhibiting the most potent antagonistic activity and selectivity over the α3β2 and α4β2 nAChR subtypes. Final electrophysiological characterization demonstrated that TP-2212-59 inhibited acetylcholine evoked currents in α3β4 nAChRs heterogeneously expressed in Xenopus laevis oocytes with a calculated IC50 of 2.3 nM and exhibited more than 1000-fold selectivity over the α3β2 and α7 nAChR subtypes. As such, TP-2212-59 is among the most potent α3β4 nAChRs antagonists identified to date and further demonstrates the utility of mixture-based combinatorial libraries in the discovery of novel α-conotoxin derivatives with refined pharmacological activity.
authors.affiliation: Torrey Pines Institute for Molecular Studies , 11350 SW Village Parkway, Port St. Lucie, Florida 34987, United States.
authors.forename: Yi-Pin
authors.initials: YP
authors.lastname: Chang
authors.forename: Jayati
authors.initials: J
authors.lastname: Banerjee
authors.forename: Cheryl
authors.initials: C
authors.lastname: Dowell
authors.forename: Jinhua
authors.initials: J
authors.lastname: Wu
authors.forename: Reena
authors.initials: R
authors.lastname: Gyanda
authors.forename: Richard A
authors.initials: RA
authors.lastname: Houghten
authors.forename: Lawrence
authors.initials: L
authors.lastname: Toll
authors.forename: J Michael
authors.initials: JM
authors.lastname: McIntosh
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Armishaw
mesh_terms: D020650:Combinatorial Chemistry Techniques / Q000379:methods*; D020916:Conotoxins / Q000494:pharmacology*; D055808:Drug Discovery; D004353:Drug Evaluation, Preclinical; D057809:HEK293 Cells; D006801:Humans; D008564:Membrane Potentials / Q000187:drug effects; D018733:Nicotinic Antagonists / Q000138:chemical synthesis* / Q000494:pharmacology; D011978:Receptors, Nicotinic / Q000737:chemistry / Q000187:drug effects*; D013329:Structure-Activity Relationship
chemical_list: D020916:Conotoxins; D018733:Nicotinic Antagonists; D011978:Receptors, Nicotinic; C403530:nicotinic receptor alpha3beta4