Related Experiment Video
Updated: Jun 28, 2025
06:07
Author Spotlight: Establishing a New Fluorescence-Based Protocol for In Vivo Mitochondrial Morphology Analysis in Parkinson's Disease
Published on: June 23, 2023
1.6K
Elevated α-synuclein levels inhibit mitophagic flux.
Inge Kinnart1, Liselot Manders1, Thibaut Heyninck1
1Department of Neurosciences, Laboratory for Parkinson Research, KU Leuven, Leuven, Belgium.
NPJ Parkinson'S Disease
|April 9, 2024
Summary
Elevated alpha-synuclein (α-synuclein) levels impair mitophagy, a cellular process for clearing damaged mitochondria, contributing to Parkinson's disease (PD). This disruption is linked to altered actin dynamics, not impaired PINK1/parkin signaling.
Area of Science:
- Neuroscience
- Cell Biology
- Genetics
Background:
- Parkinson's disease (PD) is linked to alpha-synuclein (α-synuclein) gene multiplications, suggesting elevated α-synuclein causes PD.
- Mitochondria are implicated as a key target of α-synuclein-induced cellular damage.
- Mitophagy, mediated by PINK1/parkin/DJ-1, is a critical cellular defense for removing damaged mitochondria.
Purpose of the Study:
- To investigate the impact of elevated α-synuclein levels on mitophagic flux and non-mitochondrial autophagy.
- To determine if α-synuclein affects the PINK1/parkin/DJ-1 mitophagy pathway.
- To explore the role of actin dynamics in α-synuclein-induced mitophagy defects.
Main Methods:
- Quantification of mitophagic and non-mitochondrial autophagic flux in three distinct models: Drosophila melanogaster, human skin fibroblasts, and human induced pluripotent stem cell (iPSC)-derived neurons.
- Transgenic expression and transfection of wild-type and mutant α-synuclein, as well as β-synuclein.
- Doxycycline-inducible upregulation of wild-type SNCA in iPSC-derived neurons.
Main Results:
- Elevated α-synuclein levels significantly suppressed mitophagic flux across all three models, while non-mitochondrial autophagy remained unaffected.
- A twofold increase in wild-type α-synuclein in human neurons was sufficient to induce mitophagy suppression.
- PINK1/parkin activation and DJ-1 mitochondrial translocation were not impaired by α-synuclein upregulation.
- Overexpression of cofilin or inhibition of the Arp2/3 complex rescued mitophagy, indicating excessive actin network stabilization mediates the defect.
Conclusions:
- Elevated α-synuclein levels potently inhibit mitophagic flux, a crucial process in Parkinson's disease pathogenesis.
- The observed mitophagy defect is mediated by disruptions in actin dynamics, specifically excessive actin network stabilization.
- Targeting actin dynamics may offer a novel therapeutic strategy for Parkinson's disease associated with α-synucleinopathies.
