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Aging disrupts the coordination between mRNA and protein expression in mouse and human midbrain
Silas A Buck1,2, Samuel J Mabry2, Jill R Glausier2
1Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA.
Molecular Psychiatry
|January 28, 2025
Summary
Healthy aging shows decreased dopamine neuron gene expression in mice and humans, but not cell loss. Protein levels remain stable, suggesting resilience mechanisms against neurodegeneration.
Area of Science:
- Neuroscience
- Aging Research
- Molecular Biology
Background:
- Age-related dopamine neuron loss is key in Parkinson's disease.
- The impact of healthy aging on dopamine neurons is not fully understood.
- Investigating age-related changes in dopamine neuron function is crucial.
Purpose of the Study:
- To determine if midbrain dopamine neurons degenerate during aging in mice and humans.
- To investigate age-related changes in gene and protein expression of dopamine synthesis enzymes.
- To explore potential homeostatic mechanisms in aging neurons.
Main Methods:
- Comparative analysis of midbrain neuron numbers in aging mice and humans.
- Quantitative analysis of tyrosine hydroxylase (Th) and vesicular glutamate transporter 2 (Vglut2) mRNA and protein levels.
- Examination of striatal dopaminergic terminal density and protein expression in aged subjects.
- Assessment of ribosomal gene expression in dopamine neurons.
Main Results:
- No significant age-related loss of midbrain dopamine neurons in mice or humans.
- Age-related decrease in Th and Vglut2 mRNA expression in both species.
- Striatal dopaminergic terminal density decreased in aged humans, but protein levels were maintained.
- Ribosomal gene expression was maintained or upregulated, suggesting a compensatory mechanism.
Conclusions:
- Aging impacts dopamine and glutamatergic neuron gene expression across species without significant cell death.
- Maintained protein levels in synaptic sites indicate neuronal resilience.
- Age-related transcriptional changes may be compensated by translational regulation.
- Findings suggest potential therapeutic targets for maintaining neurotransmission and neuronal resilience in aging.
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