Quinolinic Acid Amyloid-like Fibrillar Assemblies Seed α-Synuclein Aggregation

Area of Science:

• Neuroscience
• Biochemistry
• Pathology

Background:

• Quinolinic acid (QA), a tryptophan metabolite, is implicated in neurodegenerative diseases.
• Mutations in kynurenine pathway enzymes elevate QA and Parkinson's disease risk.
• QA accumulation is observed in Alzheimer's and Parkinson's disease models.

Purpose of the Study:

• Investigate the role of QA in protein aggregation and neurodegeneration.
• Determine if QA can form amyloid-like structures and seed alpha-synuclein aggregation.
• Elucidate the cellular mechanisms of QA-induced neurotoxicity.

Main Methods:

• In vitro and cell culture experiments to form QA amyloid-like assemblies.
• Thioflavin T assay, powder X-ray diffraction for characterization.
• Cellular uptake, co-localization, and propagation studies using fluorescently labeled QA.

Main Results:

• Demonstrated formation of QA amyloid-like fibrillar assemblies.
• QA nanostructures seeded and accelerated alpha-synuclein aggregation in vitro and in cells.
• Internalization and co-localization of QA assemblies with alpha-synuclein aggregates in neurons.
• Observed cell-to-cell propagation of QA assemblies.

Conclusions:

• Excess QA can form amyloid-like structures that seed alpha-synuclein aggregation.
• This process contributes to neuronal toxicity and Parkinson's disease pathogenesis.
• Metabolite amyloids represent a novel mechanism in neurodegenerative disease.