Bcl-2 protects against apoptosis-related microtubule alterations in neuronal cells

Apoptosis. 2000 Feb;5(1):43-51. doi: 10.1023/a:1009685609275.

Abstract

Bcl-2 is a gene with clear anti-apoptotic properties in neurodegenerative conditions. One of the earliest hallmarks of degeneration in neuronal cell cultures is the loss of neurite morphology. Therefore the effect of Bcl-2 on neuronal morphology and microtubule stability was studied in nerve growth factor differentiated PC12 cells. Microtubule dynamics were modulated using the microtubule stabilizer taxol and the microtubule destabilizer, okadaic acid, a protein phosphatase inhibitor. It was shown that Bcl-2 protects against both taxol- and okadaic acid induced neurite retraction. Bcl-2 overexpression also significantly reduced the increased ratio of acetylated tubulin over total tubulin induced by taxol treatment. Interestingly, Bcl-2 attenuates the decrease of the same ratio after exposure to okadaic acid, suggesting that Bcl-2 is able to normalize the level of acetylated tubulin. In addition, cell death and nuclear fragmentation, induced by okadaic acid, were reduced in Bcl-2 overexpressing cells. This protection is either downstream or independent of tau phosphorylation as quantitative immunocytochemistry with AT8 showed that Bcl-2 did not modify the level of tau phosphorylation. The data suggest that the protective effect of Bcl-2 on the neuronal cytoskeleton is probably linked to changes in the post-translational modification of tubulin.

MeSH terms

  • Acetylation / drug effects
  • Animals
  • Apoptosis*
  • Cell Survival
  • Enzyme-Linked Immunosorbent Assay
  • Genes, bcl-2
  • Microtubules / metabolism*
  • Neurites / drug effects
  • Neurites / ultrastructure
  • Neurons / drug effects
  • Neurons / ultrastructure*
  • Okadaic Acid / pharmacology
  • Paclitaxel / pharmacology
  • Phosphorylation / drug effects
  • Protein Processing, Post-Translational
  • Proto-Oncogene Proteins c-bcl-2 / biosynthesis*
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Rats
  • Transfection
  • tau Proteins / metabolism

Substances

  • Proto-Oncogene Proteins c-bcl-2
  • tau Proteins
  • Okadaic Acid
  • Paclitaxel