Specific Targeting of Pro-Death NMDA Receptor Signals with Differing Reliance on the NR2B PDZ Ligand

F. X. Soriano, M. A. Martel, S. Papadia, A. Vaslin, P. Baxter, C. Rickman, J. Forder, M. Tymianski, R. Duncan, M. Aarts, P. Clarke, D. J. Wyllie, G. E. Hardingham

Research output: Contribution to journalArticlepeer-review

Abstract

NMDA receptors (NMDARs) mediate ischemic brain damage, for which interactions between the C termini of NR2 subunits and PDZ domain proteins within the NMDAR signaling complex (NSC) are emerging therapeutic targets. However, expression of NMDARs in a non-neuronal context, lacking many NSC components, can still induce cell death. Moreover, it is unclear whether targeting the NSC will impair NMDAR-dependent prosurvival and plasticity signaling. We show that the NMDAR can promote death signaling independently of the NR2 PDZ ligand, when expressed in non-neuronal cells lacking PSD-95 and neuronal nitric oxide synthase (nNOS), key PDZ proteins that mediate neuronal NMDAR excitotoxicity. However, in a non-neuronal context, the NMDAR promotes cell death solely via c-Jun N-terminal protein kinase (JNK), whereas NMDAR-dependent cortical neuronal death is promoted by both JNK and p38. NMDAR-dependent pro-death signaling via p38 relies on neuronal context, although death signaling by JNK, triggered by mitochondrial reactive oxygen species production, does not. NMDAR-dependent p38 activation in neurons is triggered by submembranous Ca2+, and is disrupted by NOS inhibitors and also a peptide mimicking the NR2B PDZ ligand (TAT-NR2B9c). TAT-NR2B9c reduced excitotoxic neuronal death and p38-mediated ischemic damage, without impairing an NMDAR-dependent plasticity model or prosurvival signaling to CREB or Akt. TAT-NR2B9c did not inhibit JNK activation, and synergized with JNK inhibitors to ameliorate severe excitotoxic neuronal loss in vitro and ischemic cortical damage in vivo. Thus, NMDAR-activated signals comprise pro-death pathways with differing requirements for PDZ protein interactions. These signals are amenable to selective inhibition, while sparing synaptic plasticity and prosurvival signaling.
Original languageEnglish
Pages (from-to)10696-10710
Number of pages15
JournalThe Journal of Neuroscience
Volume28
Issue number42
DOIs
Publication statusPublished - Oct 2008

Keywords / Materials (for Non-textual outputs)

  • NMDA receptor
  • neuronal death
  • PDZ domains
  • stroke
  • calcium
  • mitochondria
  • neuroprotection
  • nitric oxide
  • protein kinase
  • signal transduction

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