Elucidating Functional Selectivity at the 5‐HT2A Receptor

Abstract

There has been a recent resurgence of clinical interest in the application of psychedelic drugs for the treatment of various disease states. While the field is mostly focused on action within the central nervous system, previously published data from our lab supports the use of these 5‐hydroxytryptamine 2A receptor (5‐HT2AR) agonists as modulators of the inflammatory pathway in the periphery – with potential applications ranging from treatment to prevention of a spectrum of inflammation‐based diseases (e.g., asthma, atherosclerosis, Alzheimer's, Crohn's, etc.). The ligand selected for further analysis in our in vivo models of asthma and atherosclerosis, (R)‐2,5‐dimethoxy‐4‐iodoamphetamine [(R)‐DOI], demonstrates superpotent anti‐inflammatory characteristics. Whereas these whole organism models will provide insight into the physiological response profile, the mechanism of action and structural basis of the anti‐inflammatory effects have yet to be elucidated. Examining a panel of 5‐HT2AR ligands, we are elucidating the differential activation of effector pathways with particular focus on the structure‐activity relationship (SAR). Initial results from examination of the canonical G〈q pathway using a calcium mobilization measure show an experimentally validating response for the endogenous ligand serotonin, as well as, exhibit ligand‐dependent differential activation. Interestingly, (R)‐2C‐BCB showed a significant increase in percent calcium mobilization versus the remainder of the panel, which suggests the possibility that it is strongly biased towards the G〈q pathway. Ongoing studies are examining ®‐Arrestin signaling via a comparative analysis of ERK phosphorylation, ®‐Arrestin recruitment through a luciferase reporter gene assay, receptor internalization kinetics utilizing Fluorogen Activating Peptide (FAP) technology in a fluorescence depletion assay, and any additional GPCR signaling (Gi/o/s) via a comparative analysis of cAMP accumulation. The collective analysis of a comprehensive panel of 5HT2AR ligands has never been examined in this fashion; thus, we hope to apply the generated data and SAR to develop novel molecular therapies targeting specific effector pathways.Support or Funding InformationEleusis PBC