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Changes in gene transcription during a beta-mediated cell death
K Iwasaki1, T Sunderland, J W Kusiak
1Section on Geriatric Psychiatry, National Institute of Mental Health, Bethesda, MD 20892-1264, USA.
Abstract:
The a beta peptide induces cell death in neurons grown in cell culture. Previous studies have shown that the mechanism of a beta-mediated cell death of central nervous system neurons appears to be via apoptosis. Apoptosis is an active process that involves both gene transcription and translation. Using semi-quantitative polymerase chain reaction, we have analyzed the levels of a variety of transcripts in primary neuronal cultures treated with a beta that are likely to play important roles in apoptosis. Following addition of 10 microM a beta 1-42 the immediate early response gene, c-fos, shows a rapid and sustained increase in transcript level while c-jun levels increase at a slower rate. Bcl-2 and its homologues, bcl-X and bax, also increase in amount with bcl-2 and bcl-X increasing more rapidly than bax. These data provide support indicating that a beta-mediated cell death in central nervous system neurons is an active process similar to that seen in apoptosis.
Insights
Amyloid beta peptide triggers programmed cell death (apoptosis) in central nervous system neurons. This study identifies key gene expression changes, revealing apoptosis as an active, regulated process in neurodegeneration.
Area of Science:
- Neuroscience
- Molecular Biology
- Cell Biology
Background:
- Amyloid beta peptide is implicated in neuronal cell death.
- Amyloid beta-mediated neurotoxicity in the central nervous system is thought to occur via apoptosis.
- Apoptosis is a genetically regulated process involving gene transcription and translation.
Purpose of the Study:
- To investigate the molecular mechanisms of amyloid beta-induced neuronal cell death.
- To analyze the transcript levels of genes involved in apoptosis in response to amyloid beta peptide.
- To determine if amyloid beta-mediated neurodegeneration is an active apoptotic process.
Main Methods:
- Primary neuronal cultures were treated with amyloid beta 1-42 peptide.
- Semi-quantitative polymerase chain reaction (PCR) was used to analyze transcript levels.
- Levels of immediate early response genes (c-fos, c-jun) and apoptosis-related genes (Bcl-2, bcl-X, bax) were quantified.
Main Results:
- Amyloid beta 1-42 treatment rapidly and sustainedly increased c-fos transcript levels.
- c-jun transcript levels showed a slower increase following amyloid beta 1-42 exposure.
- Bcl-2, bcl-X, and bax transcript levels also increased, with Bcl-2 and bcl-X showing faster kinetics than bax.
Conclusions:
- Amyloid beta-induced neuronal cell death in the central nervous system is an active process.
- The observed changes in gene expression support a role for apoptosis in amyloid beta-mediated neurotoxicity.
- These findings contribute to understanding the molecular pathways underlying neurodegenerative processes.