Synthesis and Structure-Activity Relationships of Tool Compounds Based on WAY163909, a 5-HT2C Receptor Agonist

In Vivo and In Vitro Analyses of Novel Peptidomimetic Disruptors for the Serotonin 5-HT2C Receptor Interaction With Phosphatase and Tensin Homolog

Hypofunction of the serotonin (5-HT) 5-HT_2C receptor (5-HT_2CR) has been implicated in a variety of disorders including substance use disorders. As such, approaches to enhance 5-HT_2CR signaling display therapeutic potential. In the present study, we show that disruption of the 5-HT_2CR interaction with the protein phosphatase and tensin homolog (PTEN) via peptidomimetics enhances 5-HT_2CR-mediating signaling in vitro and potentiates selective 5-HT_2CR agonists in behavioral rodent models. Overall, the present study provides further evidence that 5-HT_2CR activity can be modulated through an allosteric protein-protein interaction. This work provides the groundwork for the continued exploration of protein-protein interactions that can allosterically modulate this critical receptor and other important G protein-coupled receptors (GPCRs) for new therapeutic development through mechanisms that may display clinical utility.

Design, Synthesis, and Characterization of 4-Undecylpiperidine-2-carboxamides as Positive Allosteric Modulators of the Serotonin (5-HT) 5-HT2C Receptor

An impaired signaling capacity of the serotonin (5-HT) 5-HT_2C receptor (5-HT_2CR) has been implicated in the neurobehavioral processes that promote relapse vulnerability in cocaine use disorder (CUD). Restoration of the diminished 5-HT_2CR signaling through positive allosteric modulation presents a novel therapeutic approach. Several new molecules with the 4-alkylpiperidine-2-carboxamide scaffold were designed, synthesized, and pharmacologically evaluated, leading to the discovery of selective 5-HT_2CR positive allosteric modulators (PAMs). Compound 16 (CYD-1-79) potentiated 5-HT-evoked intracellular calcium release in cells stably expressing the human 5-HT_2CR but not the 5-HT_2AR cells. A topographically distinct allosteric site was identified based on the newly solved 5-HT_2CR structure. Compound 16 modulated 5-HT_2CR-mediated spontaneous ambulation, partially substituted for the training dose of the 5-HT_2CR agonist WAY163909, synergized with a low dose of WAY163909 to substitute fully for the stimulus effects of WAY163909, and attenuated relapse vulnerability as assessed in a rodent self-administration model, indicating its therapeutic promise for CUD.

Synthesis and activity of functionalizable derivatives of the serotonin (5-HT) 5-HT2A receptor (5-HT2AR) antagonist M100907

The approach of tethering together two known receptor ligands, to be used as molecular probes for the study of G protein-coupled receptor (GPCR) systems, has proven to be a valuable approach. Selective ligands that possess functionality that can be used to link to other ligands, are useful in the development of novel antagonists and agonists. Such molecules can also be attached to reporter molecules, such as fluorophores, for the study of GPCR dimerization and its role in signaling. The highly selective serotonin (5-HT) 5-HT_2A receptor (5-HT_2AR) antagonist M100907 (volinanserin) is of clinical interest in the treatment of neurological and mental health disorders. Here, we synthesized the most active (+)-M100907 enantiomer as well as a series of derivatives that possessed either an alkyne or an azide. The triazole resulting from the dipolar cycloaddition of these groups did not interfere with the ability of the bivalent ligand to act as an antagonist. Thus, we have synthesized a number of compounds which will prove useful in elucidating the role of the 5-HT_2AR in the central nervous system.