Prostaglandin E2 type 1 receptors contribute to neuronal apoptosis after transient forebrain ischemia

J Cereb Blood Flow Metab. 2013 Aug;33(8):1207-14. doi: 10.1038/jcbfm.2013.69. Epub 2013 May 1.

Abstract

Cyclooxygenase-2-derived prostaglandin E2 (PGE2) contributes to excitotoxic and ischemic neuronal cell death by engaging neuronal PGE2 type 1 receptors (EP1R). Our previous studies have shown that EP1R signaling resulted in disturbances of intracellular Ca(2+) homeostasis and suppression of the pro-survival protein kinase AKT. The aim of this study was to investigate whether these pathophysiological mechanism have a role in the neuronal cell death after transient forebrain ischemia. Mice were subjected to ischemia/reperfusion by bilateral common carotid artery occlusion. Hippocampal cornu ammonis area 1 (CA1) neuronal cell death was determined 5 days after reperfusion. Animals treated with the EP1R antagonist SC51089 or EP1R-deficient mice (EP1(-/-)) showed significantly less neuronal injury as compared to vehicle-treated wild-type controls. Benefits of EP1R blockage were still evident 14 days after injury. Better neuronal survival was correlated with reduced neuronal caspase-3 activity and decreased nuclear translocation of the apoptosis-inducing factor . Neuroprotection could be reverted by intracerebroventricular administration of the phosphoinositide 3-kinase inhibitor LY294002 and was not further increased by the calcineurin inhibitor FK506. These data implicate EP1R in postischemic neuronal apoptosis possibly by facilitating AKT inhibition.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Apoptosis Inducing Factor / genetics
  • Apoptosis Inducing Factor / physiology
  • Blotting, Western
  • CA1 Region, Hippocampal / pathology
  • Calcineurin / metabolism
  • Calcineurin Inhibitors
  • Caspase 3 / metabolism
  • Dinoprostone / metabolism
  • Hydrazines / pharmacology
  • Immunohistochemistry
  • Ischemic Attack, Transient / pathology*
  • Mice
  • Mice, Inbred C57BL
  • Neurons / physiology*
  • Oncogene Protein v-akt / metabolism
  • Oxazepines / pharmacology
  • Phosphoinositide-3 Kinase Inhibitors
  • Phosphorylation
  • Protein Transport
  • Receptors, Prostaglandin E, EP1 Subtype / antagonists & inhibitors
  • Receptors, Prostaglandin E, EP1 Subtype / physiology*

Substances

  • Apoptosis Inducing Factor
  • Calcineurin Inhibitors
  • Hydrazines
  • Oxazepines
  • Phosphoinositide-3 Kinase Inhibitors
  • Ptger1 protein, mouse
  • Receptors, Prostaglandin E, EP1 Subtype
  • SC 51089
  • Oncogene Protein v-akt
  • Calcineurin
  • Caspase 3
  • Dinoprostone