Digital seed amplification assay for TDP-43 aggregate quantification in CSF.

Area of Science:

• Neuroscience
• Biochemistry
• Biotechnology

Background:

• Dementia is often caused by misfolded protein aggregates, with subtypes presenting overlapping symptoms that complicate diagnosis.
• Accurate diagnosis of dementia subtypes is challenging without reliable biomarkers, hindering effective drug development.
• Transactive response deoxyribonucleic acid binding protein 43 (TDP-43) pathology is implicated in several neurodegenerative diseases.

Purpose of the Study:

• To develop a precise and sensitive method for quantifying TDP-43 seeds in cerebrospinal fluid (CSF).
• To establish a diagnostic tool for frontotemporal lobar dementia with TDP (FTLD-TDP) and related conditions.

Main Methods:

• Development of a digital seed amplification assay (dSAA) utilizing nanoliter compartments.
• Isolation and precise quantification of individual TDP-43 protein aggregates in CSF samples.
• Testing of 40 CSF samples from FTLD-TDP patients and healthy controls.

Main Results:

• The dSAA demonstrated high sensitivity in detecting TDP-43 seeds.
• Elevated TDP-43 seed concentrations were found in FTLD-TDP patients compared to controls.
• Seed concentrations correlated with disease severity in FTLD-TDP patients.

Conclusions:

• The dSAA is a novel, quantitative, and high-sensitivity assay for TDP-43 seeds in CSF.
• The assay offers single-aggregate resolution with low limits of detection and quantification.
• This technology provides a foundation for diagnostic and monitoring tools for TDP-43-related diseases like FTLD-TDP.