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Author Notes:

Correspondence: strayne@emory.edu (SFT); hyuan@emory.edu (HY)

KKO and WC contributed equally to this work.

Conceptualization: KKO SAS AEC EA LZF SP SFT HY. Data curation: SAS AEC EA SP SFT HY. Formal analysis: KKO WC SAS MJM LZF GJK AJS SB AEC EA SP SFT HY.

Funding acquisition: EA LZF AEC WC SFT HY. Investigation: KKO WC MJM LZF CH AT HK GJK AJS ZS JP SB HY. Methodology: KKO WC SAS MJM LZF GJK AJS SB AEC EA SP SFT HY.

Project administration: SP AEC EA SFT HY. Resources: KKO WC SAS MJM LZF CH AT HK GJK AJS ZS JP SB SP AEC EA SFT HY. Supervision: SFT HY.

Validation: SAS SP AEC EA SFT HY. Visualization: KKO LZF AEC EA SAS SP SFT HY. Writing – original draft: KKO WC SAS MJM LZF CH AT HK GJK AJS ZS JP SB SP AEC EA SFT HY.

We thank Jing Zhang, Phuoung Le, Karen A. Hartnett, and Shivani Gaur for outstanding technical assistance.

We thank the Genome Aggregation Database (gnomAD) and the groups that provided exome and genome variant data to this resource. A full list of contributing groups can be found at http://gnomad.broadinstitute.org/about.

We also thank the Exome Aggregation Consortium and the groups that provided exome variant data for comparison; a full list of contributing groups can be found at http://exac.broadinstitute.org/about.

The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Competing Interests: SFT is a consultant of Janssen Pharmaceuticals, Boehringer Ingelheim Pharma GmbH, and Pfizer Inc, and co-founder of NeurOp Inc. SP serves on the advisory board and is an equity holder of Pairnomix. AEC is a founder of Q-State Biosciences.

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Research Funding:

This work was supported by the Eunice Kennedy Shriver National Institute Of Child Health & Human Development (NICHD) of the National Institutes of Health (NIH) under award number R01HD082373 to HY, by the National Institute of Neurological Disorders and Stroke (NINDS) of the NIH under award number R01NS036654 to SFT, award number R24NS092989 to SFT, and award number R01NS043277 to EA, by the Xiangya-Emory Medical Schools Visiting Student Program to WC, by Emory+Children’s Pediatric Center Seed Grant Program to HY, and by the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR000454 to HY.

LZF and AEC are supported by the Howard Hughes Medical Institute

SP is supported by the National Health and Medical Research Council of Australia.

Keywords:

  • Glutamate
  • Neurons
  • Glycine
  • Complementary DNA
  • Neuronal dendrites
  • Single channel recordings
  • Transfection
  • Excitatory postsynaptic potentials

Molecular Mechanism of Disease-Associated Mutations in the Pre-M1 Helix of NMDA Receptors and Potential Rescue Pharmacology.

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Journal Title:

PLoS Genetics

Volume:

Volume 13, Number 1

Publisher:

, Pages e1006536-e1006536

Type of Work:

Article | Final Publisher PDF

Abstract:

N-methyl-D-aspartate receptors (NMDARs), ligand-gated ionotropic glutamate receptors, play key roles in normal brain development and various neurological disorders. Here we use standing variation data from the human population to assess which protein domains within NMDAR GluN1, GluN2A and GluN2B subunits show the strongest signal for being depleted of missense variants. We find that this includes the GluN2 pre-M1 helix and linker between the agonist-binding domain (ABD) and first transmembrane domain (M1). We then evaluate the functional changes of multiple missense mutations in the NMDAR pre-M1 helix found in children with epilepsy and developmental delay. We find mutant GluN1/GluN2A receptors exhibit prolonged glutamate response time course for channels containing 1 or 2 GluN2A-P552R subunits, and a slow rise time only for receptors with 2 mutant subunits, suggesting rearrangement of one GluN2A pre-M1 helix is sufficient for rapid activation. GluN2A-P552R and analogous mutations in other GluN subunits increased the agonist potency and slowed response time course, suggesting a functionally conserved role for this residue. Although there is no detectable change in surface expression or open probability for GluN2A-P552R, the prolonged response time course for receptors that contained GluN2A-P552R increased charge transfer for synaptic-like activation, which should promote excitotoxic damage. Transfection of cultured neurons with GluN2A-P552R prolonged EPSPs, and triggered pronounced dendritic swelling in addition to excitotoxicity, which were both attenuated by memantine. These data implicate the pre-M1 region in gating, provide insight into how different subunits contribute to gating, and suggest that mutations in the pre-M1 helix can compromise neuronal health. Evaluation of FDA-approved NMDAR inhibitors on the mutant NMDAR-mediated current response and neuronal damage provides a potential clinical path to treat individuals harboring similar mutations in NMDARs.

Copyright information:

© 2017 Ogden et al

This is an Open Access work distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).
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