Application of Fluorine- and Nitrogen-Walk Approaches: Defining the Structural and Functional Diversity of 2-Phenylindole Class of Cannabinoid 1 Receptor Positive Allosteric Modulators

J Med Chem. 2020 Jan 23;63(2):542-568. doi: 10.1021/acs.jmedchem.9b01142. Epub 2020 Jan 3.

Abstract

Cannabinoid 1 receptor (CB1R) allosteric ligands hold a far-reaching therapeutic promise. We report the application of fluoro- and nitrogen-walk approaches to enhance the drug-like properties of GAT211, a prototype CB1R allosteric agonist-positive allosteric modulator (ago-PAM). Several analogs exhibited improved functional potency (cAMP, β-arrestin 2), metabolic stability, and aqueous solubility. Two key analogs, GAT591 (6r) and GAT593 (6s), exhibited augmented allosteric-agonist and PAM activities in neuronal cultures, improved metabolic stability, and enhanced orthosteric agonist binding (CP55,940). Both analogs also exhibited good analgesic potency in the CFA inflammatory-pain model with longer duration of action over GAT211 while being devoid of adverse cannabimimetic effects. Another analog, GAT592 (9j), exhibited moderate ago-PAM potency and improved aqueous solubility with therapeutic reduction of intraocular pressure in murine glaucoma models. The SAR findings and the enhanced allosteric activity in this class of allosteric modulators were accounted for in our recently developed computational model for CB1R allosteric activation and positive allosteric modulation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Regulation / drug effects
  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / chemical synthesis*
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacokinetics
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology
  • Biotransformation
  • Fluorine / chemistry*
  • Freund's Adjuvant
  • HEK293 Cells
  • Humans
  • Indoles / chemistry*
  • Indoles / pharmacokinetics
  • Indoles / pharmacology
  • Inflammation / chemically induced
  • Inflammation / prevention & control
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Neurons / drug effects
  • Nitrogen / chemistry*
  • Receptor, Cannabinoid, CB1 / agonists
  • Receptor, Cannabinoid, CB1 / drug effects*
  • Stereoisomerism
  • Structure-Activity Relationship

Substances

  • 3-(2-nitro-1-phenylethyl)-2-phenyl-1H-indole
  • Anti-Inflammatory Agents, Non-Steroidal
  • Indoles
  • Receptor, Cannabinoid, CB1
  • Fluorine
  • Freund's Adjuvant
  • Nitrogen