Induction of Bcl-2 by Functional Regulation of G-protein Coupled Receptors Protects From Oxidative Glutamate Toxicity by Increasing Glutathione

Free Radic Res. 2006 Nov;40(11):1113-23. doi: 10.1080/10715760600838191.

Abstract

Glutamate treatment depletes hippocampal HT22 cells of glutathione, which renders the cells incapable to reduce reactive oxygen species and ultimately cumulates in cell death by oxidative stress. HT22 cells resistant to glutamate displayed increased phosphorylation of cAMP-response-element binding (CREB) and decreased ERK1/2 suggestive of differences in signal transmission. We investigated the amount of candidate G-protein-coupled receptors involved in this resistance and found an increase in mRNA for receptors activated by the vasoactive intestinal peptide VIP (VPAC2, 12.6-fold) and glutamate like the metabotropic glutamate receptor mGlu1 (5.3-fold). Treating cells with VIP and glutamate led to the same changes in protein phosphorylation observed in resistant cells and induced the proto-oncogene Bcl-2. Bcl-2 overexpression protected by increasing the amount of intracellular glutathione and Bcl-2 knockdown by small interfering RNAs (siRNA) increased glutamate susceptibility of resistant cells. Other receptors upregulated in this paradigm might represent useful targets in the treatment of neurological diseases associated with oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Survival
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Dose-Response Relationship, Drug
  • Glutamates / metabolism
  • Glutathione / metabolism*
  • Hippocampus / metabolism
  • Humans
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Oxidative Stress
  • Plasmids / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • RNA, Small Interfering / metabolism
  • Receptors, G-Protein-Coupled / metabolism*

Substances

  • CREB1 protein, human
  • Cyclic AMP Response Element-Binding Protein
  • Glutamates
  • Proto-Oncogene Proteins c-bcl-2
  • RNA, Small Interfering
  • Receptors, G-Protein-Coupled
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Glutathione