Huntington's disease cerebrospinal fluid seeds aggregation of mutant huntingtin

Area of Science:

• Neurodegenerative diseases
• Molecular biology
• Biomarker development

Background:

• Huntington's disease (HD) is a progressive neurodegenerative disorder.
• It is caused by an expanded CAG triplet repeat leading to mutant huntingtin protein (mHTT) with a polyglutamine expansion.
• The onset of HD symptoms is unpredictable in gene-carrying individuals.

Purpose of the Study:

• To investigate the potential of using seeding assays to detect and monitor Huntington's disease.
• To explore the prion-like propagation mechanism of mutant huntingtin aggregation.
• To develop a molecular biomarker for HD diagnosis and therapeutic evaluation.

Main Methods:

• Utilized synthetic polyglutamine oligomers and cerebrospinal fluid (CSF) from BACHD transgenic rats and human HD subjects.
• Employed a cell model and its lysate to observe mutant huntingtin aggregation.
• Applied light and cryo-electron microscopy to visualize the nucleation and enhancement of aggregation by synthetic seeds.

Main Results:

• Synthetic oligomers and CSF from HD subjects and rats successfully seeded mutant huntingtin aggregation in vitro.
• Seeding was dependent on the presence of the mutant huntingtin template, suggesting a prion-like mechanism.
• The developed seeding assay could accurately distinguish HD patients from healthy and non-HD dementia controls in blinded samples.

Conclusions:

• Mutant huntingtin aggregation can be initiated by seeding, potentially via a prion-like propagation pathway.
• The seeding property observed in HD patient CSF offers a promising basis for a novel molecular biomarker.
• This assay could aid in monitoring HD progression and assessing the effectiveness of therapies targeting mHTT.