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Updated: Jul 15, 2026
Live Imaging of the Mitochondrial Glutathione Redox State in Primary Neurons using a Ratiometric Indicator
Published on: October 20, 2021
Decreased level of mitochondrial RNA by glutamate in cultured cortical neurons
Chie Sugiyama1, Nobuyuki Kuramoto, Keiichi Seko
1Department of Pharmacology, Setsunan University Faculty of Pharmaceutical Sciences, Hirakata, Osaka, Japan.
Abstract:
Mitochondrial injury is induced by a decline in mitochondrial function as well as by damaged mitochondrial DNA. In this study, we evaluate the effects of glutamate exposure on the level of mitochondrial mRNA in cultured cortical neurons of mice. Glutamate exposure for 15 min significantly reduced cell viability 24 h later. Under these experimental conditions, glutamate was effective in reducing the level of mitochondrial mRNAs, especially the mRNAs of NADH-ubiquinone oxidoreductase subunits (nd1 and nd6), 6 h after the exposure. Southern blot analysis, however, revealed no significant change in that of the mitochondrial DNA at any time after glutamate exposure. These results suggest that the activation of glutamate signals negatively regulated the expression of mitochondrial mRNA, without affecting the level of mitochondrial DNA.
Insights
Glutamate exposure damages mouse neurons by reducing mitochondrial mRNA levels, specifically for NADH-ubiquinone oxidoreductase subunits. This occurs without altering the mitochondrial DNA itself, indicating a regulatory effect on gene expression.
Area of Science:
- Neuroscience
- Mitochondrial Biology
- Molecular Biology
Background:
- Mitochondrial injury impairs cellular function and can stem from mitochondrial DNA damage.
- Glutamate is a key neurotransmitter implicated in neuronal function and excitotoxicity.
Purpose of the Study:
- To investigate the impact of glutamate exposure on mitochondrial mRNA levels in cultured mouse cortical neurons.
- To determine if glutamate affects mitochondrial DNA integrity.
Main Methods:
- Primary cortical neurons from mice were exposed to glutamate.
- Cell viability was assessed 24 hours post-exposure.
- Mitochondrial mRNA levels (nd1, nd6) were quantified at various time points using molecular techniques.
- Mitochondrial DNA integrity was analyzed via Southern blot.
Main Results:
- Short glutamate exposure (15 min) significantly reduced neuronal viability after 24 hours.
- Glutamate exposure led to a significant decrease in mitochondrial mRNA levels, particularly for NADH-ubiquinone oxidoreductase subunits (nd1 and nd6), by 6 hours.
- Southern blot analysis showed no significant changes in mitochondrial DNA levels at any time point following glutamate exposure.
Conclusions:
- Glutamate signaling negatively regulates mitochondrial mRNA expression in cortical neurons.
- The observed reduction in mitochondrial mRNA occurs independently of changes in mitochondrial DNA levels.
- These findings highlight a specific mechanism of glutamate-induced mitochondrial dysfunction at the post-transcriptional level.
