Pathogenic lysosomal depletion in Parkinson's disease
Benjamin Dehay1, Jordi Bové, Natalia Rodríguez-Muela
1Neurodegenerative Diseases Research Group, Vall d'Hebron Research Institute-Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Barcelona 08035, Spain.
Summary
Parkinson's disease involves autophagosome accumulation due to lysosome depletion, not autophagy induction. Restoring lysosome levels protects against neurodegeneration in this Parkinson's disease model.
Area of Science:
- Neuroscience
- Cell Biology
- Neurodegenerative Diseases
Background:
- Autophagy dysregulation is implicated in Parkinson's disease (PD).
- Autophagosomes (AP) accumulate in PD brains, often attributed to increased autophagy.
- The underlying cause and pathogenic role of AP accumulation in PD remain unclear.
Purpose of the Study:
- To investigate the cause of autophagosome accumulation in a mouse model of Parkinson's disease.
- To determine the role of lysosomes in autophagosome clearance and neurodegeneration in PD.
- To explore therapeutic strategies targeting lysosomal function for PD treatment.
Main Methods:
- Utilized the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD.
- Assessed lysosomal levels, autophagosome accumulation, and dopaminergic cell death.
- Investigated the role of mitochondrial reactive oxygen species (ROS) in lysosomal membrane permeabilization.
- Examined PD brain samples for lysosomal and autophagosome markers.
- Tested the efficacy of inducing lysosomal biogenesis (TFEB activation) and rapamycin treatment.
Main Results:
- MPTP treatment caused a decrease in lysosomal content preceding autophagosome accumulation and dopaminergic cell death.
- Lysosomal depletion resulted from mitochondrial ROS-induced membrane permeabilization, leading to defective autophagosome clearance.
- Lysosomal proteases were ectopically released into the cytosol, contributing to neurodegeneration.
- PD brain samples showed lysosomal breakdown and autophagosome accumulation, with Lewy bodies positive for AP markers.
- Genetic or pharmacological induction of lysosomal biogenesis and rapamycin treatment restored lysosomal levels, enhanced AP clearance, and attenuated neurodegeneration.
Conclusions:
- Autophagosome accumulation in PD stems from impaired lysosomal clearance due to lysosomal depletion, not autophagy induction.
- Mitochondrial dysfunction and ROS contribute to lysosomal membrane permeabilization and subsequent neurodegeneration.
- Restoring lysosomal levels and function represents a promising neuroprotective strategy for Parkinson's disease.
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