Neuroprotective effect of ghrelin is associated with decreased expression of prostate apoptosis response-4

Endocr J. 2009;56(4):609-17. doi: 10.1507/endocrj.k09e-072. Epub 2009 Apr 7.

Abstract

Ghrelin is known to promote neuronal defense and survival against ischemic injury by inhibiting apoptotic processes. In the present study, we investigated the role of prostate apoptosis response-4 (Par-4), a proapoptotic gene the expression of which is increased after ischemic injury, in ghrelin-mediated neuroprotection during middle cerebral artery occlusion (MCAO). Both ghrelin and des-acyl ghrelin protected cortical neurons from ischemic injury. Ghrelin receptor specific antagonist abolished the protective effects of ghrelin, whereas those of des-acyl ghrelin were preserved, suggesting the involvement of a receptor that is distinct from GHS-R1a. The expression of Par-4 was increased by MCAO, which was attenuated by ghrelin and des-acyl ghrelin treatments. Both ghrelin and des-acyl ghrelin increased the Bcl-2/Bax ratio, prevented cytochrome c release, and inhibited caspase-3 activation. Our data indicate that des-acyl ghrelin, as well as ghrelin, protect cortical neurons against ischemic injury through the inhibition of Par-4 expression and apoptotic molecules in mitochondrial pathway.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Apoptosis / physiology
  • Apoptosis Regulatory Proteins / biosynthesis*
  • Brain Ischemia / metabolism
  • Caspase 3 / metabolism
  • Cytochromes c / metabolism
  • Ghrelin / pharmacology
  • Ghrelin / physiology*
  • Infarction, Middle Cerebral Artery / metabolism
  • Male
  • Neurons / drug effects
  • Neuroprotective Agents / pharmacology*
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Ghrelin / antagonists & inhibitors
  • Receptors, Ghrelin / physiology
  • Reperfusion Injury / physiopathology
  • bcl-2-Associated X Protein / metabolism

Substances

  • Apoptosis Regulatory Proteins
  • Ghrelin
  • Neuroprotective Agents
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Ghrelin
  • bcl-2-Associated X Protein
  • ghrelin, des-n-octanoyl
  • prostate apoptosis response-4 protein
  • Cytochromes c
  • Caspase 3