Protein kinase C epsilon delays latency until anoxic depolarization through arc expression and GluR2 internalization

J Cereb Blood Flow Metab. 2017 Dec;37(12):3774-3788. doi: 10.1177/0271678X17712178. Epub 2017 Jun 6.

Abstract

Global cerebral ischemia is a debilitating injury that damages the CA1 region of the hippocampus, an area important for learning and memory. Protein kinase C epsilon (PKCɛ) activation is a critical component of many neuroprotective treatments. The ability of PKCɛ activation to regulate AMPA receptors (AMPARs) remains unexplored despite the role of AMPARs in excitotoxicity after brain ischemia. We determined that PKCɛ activation increased expression of a protein linked to learning and memory, activity-regulated cytoskeleton-associated protein (arc). Also, arc is necessary for neuroprotection and confers protection through decreasing AMPAR currents via GluR2 internalization. In vivo, activation of PKCɛ increased arc expression through a BDNF/TrkB pathway, and decreased GluR2 mRNA levels. In hippocampal cultured slices, PKCɛ activation decreased AMPAR current amplitudes in an arc- and GluR2-dependent manner. Additionally, PKCɛ activation triggered an arc- and GluR2 internalization-dependent delay in latency until anoxic depolarization. Inhibiting arc also blocked PKCɛ-mediated neuroprotection against lethal oxygen and glucose deprivation. These data characterize a novel PKCɛ-dependent mechanism that for the first time defines a role for arc and AMPAR internalization in conferring neuroprotection.

Keywords: Brain ischemia; dendrites; glutamate; hippocampus; ischemic preconditioning and induced tolerance; synapses.

MeSH terms

  • Animals
  • Brain Ischemia
  • Brain-Derived Neurotrophic Factor / metabolism
  • Cells, Cultured
  • Cytoskeletal Proteins / genetics
  • Cytoskeletal Proteins / metabolism*
  • Gene Expression
  • Hippocampus / cytology
  • Hippocampus / physiology*
  • Hypoxia / genetics
  • Hypoxia / metabolism
  • Male
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Neurons / cytology
  • Neurons / metabolism
  • Neuroprotection*
  • Oxygen / metabolism
  • Protein Kinase C-epsilon / metabolism*
  • RNA, Messenger / genetics
  • Rats, Sprague-Dawley
  • Receptor, trkB / metabolism
  • Receptors, AMPA / genetics
  • Receptors, AMPA / metabolism*

Substances

  • Brain-Derived Neurotrophic Factor
  • Cytoskeletal Proteins
  • Nerve Tissue Proteins
  • RNA, Messenger
  • Receptors, AMPA
  • activity regulated cytoskeletal-associated protein
  • Ntrk2 protein, rat
  • Receptor, trkB
  • Protein Kinase C-epsilon
  • glutamate receptor ionotropic, AMPA 2
  • Oxygen