title: Different oxysterols have opposing actions at N-methyl-D-aspartate receptors.
abstract: Oxysterols have emerged as important biomarkers in disease and as signaling molecules. We recently showed that the oxysterol 24(S)-hydroxycholesterol, the major brain cholesterol metabolite, potently and selectively enhances NMDA receptor function at a site distinct from other modulators. Here we further characterize the pharmacological mechanisms of 24(S)-hydroxycholesterol and its synthetic analog SGE201. We describe an oxysterol antagonist of this positive allosteric modulation, 25-hydroxycholesterol. We found that 24(S)-hydroxycholesterol and SGE201 primarily increased the efficacy of NMDAR agonists but did not directly gate the channel or increase functional receptor number. Rather than binding to a direct aqueous-accessible site, oxysterols may partition into the plasma membrane to access the NMDAR, likely explaining slow onset and offset kinetics of modulation. Interestingly, oxysterols were ineffective when applied to the cytosolic face of inside-out membrane patches or through a whole-cell pipette solution, suggesting a non-intracellular site. We also found that another natural oxysterol, 25-hydroxycholesterol, although exhibiting slight potentiation on its own, non-competitively and enantioselectively antagonized the effects of 24(S)-hydroxycholesterol analogs. In summary, we suggest two novel allosteric sites on NMDARs that separately modulate channel gating, but together oppose each other.
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Linsenbardt
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Taylor
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Emnett
authors.affiliation: Sage Therapeutics, Cambridge, MA 02142, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Doherty
authors.affiliation: Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Kathiresan
authors.initials: K
authors.lastname: Krishnan
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Douglas F
authors.initials: DF
authors.lastname: Covey
authors.affiliation: Sage Therapeutics, Cambridge, MA 02142, USA; Appel Alzheimer's Disease Research Institute, Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY 10021, USA; Department of Psychiatry, Weill Cornell Medical College, New York, NY 10021, USA; Department of Pharmacology, Weill Cornell Medical College, New York, NY 10021, USA.
authors.forename: Steven M
authors.initials: SM
authors.lastname: Paul
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Zorumski
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anatomy & Neurobiology, Washington University School of Medicine, St. Louis, MO 63110, USA. Electronic address: menneris@psychiatry.wustl.edu.
authors.forename: Steven
authors.initials: S
authors.lastname: Mennerick
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018683:Excitatory Amino Acid Agents / Q000494:pharmacology*; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D005260:Female; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism; D006888:Hydroxycholesterols / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D018683:Excitatory Amino Acid Agents; D018690:Excitatory Amino Acid Agonists; D006888:Hydroxycholesterols; D016194:Receptors, N-Methyl-D-Aspartate; C044563:24-hydroxycholesterol; D016291:Dizocilpine Maleate; C007997:25-hydroxycholesterol
keywords: Allosteric; Gating; Modulation; NMDA receptor; Neurodegeneration