We propose to develop new kappa opioid receptor (KOR) modulators for early stage development towards treating addictive and mood disorders. Dynorphins are stress peptides and act at the KOR. Therefore, to suppress dynorphin-mediated effects, negative regulators of KOR are sought. There is considerable evidence that KOR signals through ?arrestin2 to mediate certain side effects (sedation and dysphoria) and through G proteins to mediate its analgesic and antipruritic effects. Therefore, we propose to develop compounds that antagonize the ?arrestin2-interacting receptor. Specifically we aim to deliver: 1. Competitive antagonists that are potent and efficacious in suppressing ?arrestin2 recruitment; 2. Partial agonists that are potently competitive at blocking dynorphin-stimulated ?arrestin2 recruitment while preserving full agonism in G protein signaling; 3. Negative allosteric modulators that will decrease KOR responsiveness to dynorphins. In this proposal, we present an update on the extensive progress we have made in introducing the first small molecule, G protein biased KOR agonists to the field. We also provide substantial preliminary data supporting a successful campaign to develop the aforementioned antagonists, biased partial agonists and negative allosteric modulators. In particular, the negative allosteric modulators will be first in class for this receptor. This proposal seeks 5 years of support to provide the initia preclinical characterizations and chemical optimizations of these compounds into drug candidates. In line with this goal, we will fully characterize the pharmacological properties of th compounds across functionally diverse cell-based assays with of a goal of identifying compounds capable of fine-tuning KOR responsiveness. Cell-based responses will be validated in mouse models assessing locomotor responses, antinociceptive activity and suppressing pruritis (itch response) to determine that compound maintains the pharmacological profiles in vivo. Drug metabolism and pharmacokinetics of the compounds will be performed to provide information for continued medicinal chemistry optimization rounds and to advance compounds to clinical development. Our enthusiastic team consists of established medicinal and synthetic chemists; an opioid neuropharmacologist (with both molecular and behavioral pharmacology expertise); and an expert in pharmacokinetics and drug metabolism. The development of pharmacological tools across diverse pharmacophores and correlating their properties with in vivo response profiles will provide guiding evidence of the optimal chemical and pharmacological properties required to produce the desired physiological responses.

Public Health Relevance

Chronic drug abuse, addiction and depression leads to neurological changes in dopaminergic structures in the brain. The kappa opioid receptor is located on neurons that modulate dopamine tone and may present a means to fine tune abrogate dopamine signaling in the addicted and depressed brain. This proposal will introduce new chemical means to regulate the KOR and provide essential preclinical optimization required to make new kappa opioid receptor-targeted drugs available for the treatment of addiction and mood disorders.

National Institute of Health (NIH)
National Institute on Drug Abuse (NIDA)
Research Project (R01)
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Drug Discovery for the Nervous System Study Section (DDNS)
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Shih, Ming L
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Scripps Florida
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Hirasawa, Shun; Cho, Min; Brust, Tarsis F et al. (2018) O6C-20-nor-salvinorin A is a stable and potent KOR agonist. Bioorg Med Chem Lett 28:2770-2772
Ho, Jo-Hao; Stahl, Edward L; Schmid, Cullen L et al. (2018) G protein signaling-biased agonism at the ?-opioid receptor is maintained in striatal neurons. Sci Signal 11:
Roach, Jeremy J; Sasano, Yusuke; Schmid, Cullen L et al. (2017) Dynamic Strategic Bond Analysis Yields a Ten-Step Synthesis of 20-nor-Salvinorin A, a Potent ?-OR Agonist. ACS Cent Sci 3:1329-1336
Scarry, Sarah M; Lovell, Kimberly M; Frankowski, Kevin J et al. (2016) Synthesis of Kappa Opioid Antagonists Based On Pyrrolo[1,2-?]quinoxalinones Using an N-Arylation/Condensation/Oxidation Reaction Sequence. J Org Chem 81:10538-10550
Brust, Tarsis F; Morgenweck, Jenny; Kim, Susy A et al. (2016) Biased agonists of the kappa opioid receptor suppress pain and itch without causing sedation or dysphoria. Sci Signal 9:ra117
Rankovic, Zoran; Brust, Tarsis F; Bohn, Laura M (2016) Biased agonism: An emerging paradigm in GPCR drug discovery. Bioorg Med Chem Lett 26:241-250
Bohn, Laura M; Zhou, Lei; Ho, Jo-Hao (2015) Approaches to Assess Functional Selectivity in GPCRs: Evaluating G Protein Signaling in an Endogenous Environment. Methods Mol Biol 1335:177-89
Frankowski, Kevin J; Slauson, Stephen R; Lovell, Kimberly M et al. (2015) Potency enhancement of the ?-opioid receptor antagonist probe ML140 through sulfonamide constraint utilizing a tetrahydroisoquinoline motif. Bioorg Med Chem 23:3948-56
Luttrell, Louis M; Maudsley, Stuart; Bohn, Laura M (2015) Fulfilling the Promise of ""Biased"" G Protein-Coupled Receptor Agonism. Mol Pharmacol 88:579-88
Zhou, Lei; Stahl, Edward L; Lovell, Kimberly M et al. (2015) Characterization of kappa opioid receptor mediated, dynorphin-stimulated [35S]GTP?S binding in mouse striatum for the evaluation of selective KOR ligands in an endogenous setting. Neuropharmacology 99:131-41

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