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Published on: June 23, 2023
Mitochondrial ROS-mediated post-transcriptional regulation of α-synuclein through miR-7 and miR-153
1Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL, USA.
Abstract:
Dysregulation of human alpha-synuclein (α-SYN) is one of the major contributors in the pathogenesis of Parkinson's disease. 1-methyl-4-phenylpyridinium (MPP+) is well known neurotoxin which increases α-SYN expression and causes dopaminergic neuronal death. Increasing evidence suggests microRNAs (miRNAs), especially miRNA-7 and miR-153, have important role in the regulation of α-SYN translation and they can prevent MPP+-mediated neuronal death. Here, we examined whether MPP+-mediated upregulation of α-SYN expression is directly related to miRNA-7 and miR-153. First, we established HEK293/TR cells stably expressing both miR-7 and miR-153. Human α-SYN 3'-UTR containing target sites for both miRNAs was cloned next to a luciferase reporter construct. To control the total levels of reporter mRNA, a tetracycline-inducible system was used. Compared to wild-type HEK293/TR cells, cells overexpressing both miRNAs demonstrated about 75% reduction in luciferase activity. MPP+ treatment, however, significantly increased luciferase activity of human α-SYN 3'-UTR. Either quenching mitochondrial reactive oxygen species (ROS) or translational inhibition significantly reduced MPP+-mediated luciferase activity, suggesting mitochondrial ROS is responsible for MPP+-induced α-SYN translation. Together, our results suggest that MPP+-mediated increased α-SYN levels are contributed by mitochondrial ROS-mediated de novo protein synthesis which is regulated by miRNA-7 and miR-153.
Insights
Parkinson's disease involves alpha-synuclein (α-SYN) dysregulation. Mitochondrial reactive oxygen species (ROS) drive α-SYN translation, which is regulated by miRNA-7 and miR-153, offering a potential therapeutic target.
Area of Science:
- Neuroscience
- Molecular Biology
- Genetics
Background:
- Alpha-synuclein (α-SYN) dysregulation is central to Parkinson's disease pathogenesis.
- The neurotoxin 1-methyl-4-phenylpyridinium (MPP+) elevates α-SYN and induces dopaminergic neuronal death.
- MicroRNAs (miRNAs), specifically miR-7 and miR-153, are implicated in regulating α-SYN translation and mitigating MPP+-induced neurotoxicity.
Purpose of the Study:
- To investigate the direct relationship between MPP+-induced α-SYN upregulation and the regulatory roles of miR-7 and miR-153.
- To elucidate the mechanism by which MPP+ affects α-SYN expression in the presence of these miRNAs.
Main Methods:
- Established HEK293/TR cells stably co-expressing miR-7 and miR-153.
- Cloned human α-SYN 3'-UTR with miRNA target sites into a luciferase reporter construct under a tetracycline-inducible system.
- Assessed luciferase activity following MPP+ treatment and interventions targeting mitochondrial reactive oxygen species (ROS) and translation.
Main Results:
- Overexpression of miR-7 and miR-153 significantly reduced luciferase activity, confirming their inhibitory effect on α-SYN translation.
- MPP+ treatment markedly increased luciferase activity, indicating enhanced α-SYN translation.
- Quenching mitochondrial ROS or inhibiting translation significantly reduced MPP+-mediated luciferase activity, implicating mitochondrial ROS in α-SYN translation.
Conclusions:
- MPP+-induced increases in α-SYN levels are mediated by mitochondrial ROS-dependent de novo protein synthesis.
- The regulatory action of miRNA-7 and miR-153 is crucial in controlling this MPP+-induced α-SYN translation.
- These findings highlight a potential therapeutic pathway targeting mitochondrial ROS and miRNA regulation for Parkinson's disease.
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