Mitochondrial dysfunction is a key pathological driver of early stage Parkinson's

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• The molecular origins of early sporadic Parkinson's disease (PD) are not fully understood.
• Late-stage pathology in PD obscures early disease events.
• Early and mid-stage PD brains (Braak stages 3-4) show alpha-synuclein inclusions and neuronal loss along a regional severity gradient.

Purpose of the Study:

• To investigate the molecular drivers of sporadic Parkinson's disease using the spatial pathological gradient.
• To identify early molecular events preceding alpha-synuclein inclusions and neuronal loss.

Main Methods:

• High-precision tissue sampling across 9 brain regions in Braak stage 3-4 PD brains and controls.
• Unbiased, large-scale proteomic profiling of protein expression.
• Targeted proteomic and functional analyses for verification.

Main Results:

• A biochemical gradient mirroring the spatio-temporal pathology gradient was observed.
• Two key early events identified: a metabolic switch in energy substrate utilization and perturbation of the mitochondrial redox state.
• Mitochondrial dysfunction is evident before neuronal loss and alpha-synuclein deposition, with later disease stages showing more severe mitochondrial impairment across all regions.

Conclusions:

• Mitochondrial dysfunction is a key driver of early Parkinson's disease.
• Early metabolic and redox state changes may contribute to regional vulnerability to alpha-synuclein pathology.
• This study provides an in-depth regional proteomic profile at different PD stages.