Retinal ganglion cell death and neuroprotection: Involvement of the CaMKIIalpha gene

Brain Res Mol Brain Res. 2005 Oct 3;139(2):306-16. doi: 10.1016/j.molbrainres.2005.06.008.

Abstract

The purpose of this study is to determine if calcium/calmodulin-dependent protein kinase-II (CaMKII) plays a role in neuronal cell death and if inhibition of this kinase affords some neuroprotection in the RGC-5 retinal ganglion cell line. The RGC-5 cells were treated with glutamate at various concentrations for increasing increments of time. Cytotoxicity was assayed by measuring the lactate dehydrogenase (LDH) leakage from non-viable cells and TUNEL assays. The involvement of caspase-3, Bcl-2 and caspase-8 in glutamate-induced cytotoxicity was determined by immunoblots and/or real time RT-PCR. In addition, the autocamtide-2-related inhibitory peptide (AIP), a specific inhibitor of CaMKII, was used to determine the involvement of CaMKII in glutamate-induced RGC-5 cell death. Application of increasing concentrations of glutamate to RGC-5 cells caused a dose-dependent increase in the level of cell death after 24 h. There was a glutamate-stimulated increase in the expression of caspase-8 and caspase-3 and a corresponding decrease in Bcl-2. The active fragment of caspase-3 increased in glutamate-treated cells. An early transient increase in the expression of CaMKIIalpha(B) gene and a corresponding CaMKIIalpha nuclear translocation was found in glutamate-treated cells. Treatment with AIP blocked the activation of caspase-3 and protected RGC from glutamate-mediated cell death but did not alter the glutamate-enhanced expression levels of caspase-8 or caspase-3. This report shows the likely involvement of a transcript of the CaMKIIalpha gene in the cytotoxicity response of RGC-5 cells similar to previous reports in the neural retina. AIP is shown to be a neuroprotectant for RGC-5 cells as was reported for the neural retina.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Apoptosis / drug effects*
  • Blotting, Northern / methods
  • Blotting, Western / methods
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • Carrier Proteins / pharmacology
  • Caspase 3
  • Caspase 9
  • Caspases / genetics
  • Caspases / metabolism
  • Caspases / pharmacology
  • Cell Count / methods
  • Cell Line
  • Cyclin D1 / genetics
  • Cyclin D1 / metabolism
  • Dose-Response Relationship, Drug
  • Drug Interactions
  • Fluorescent Antibody Technique / methods
  • Gene Expression Regulation / drug effects*
  • Gene Expression Regulation / physiology
  • Glutamic Acid / toxicity*
  • In Situ Nick-End Labeling / methods
  • L-Lactate Dehydrogenase / metabolism
  • Phosphorylation / drug effects
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / physiology*
  • RNA, Messenger / biosynthesis
  • Rats
  • Retinal Ganglion Cells / drug effects*
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Time Factors

Substances

  • Carrier Proteins
  • RNA, Messenger
  • Cyclin D1
  • Glutamic Acid
  • L-Lactate Dehydrogenase
  • Protein-Serine-Threonine Kinases
  • Calcium-Calmodulin-Dependent Protein Kinase Kinase
  • Casp3 protein, rat
  • Casp9 protein, rat
  • Caspase 3
  • Caspase 9
  • Caspases