Spatial mapping of α-synuclein seeding activity and pathology using immunofluorescence-integrated quiescent seed amplification

IF-QSAA multiplexing in situ quiescent seed amplification with immunofluorescence maps α-synuclein seeding activity and pathology, revealing white-matter enrichment and earlier hemispheric asymmetry than pS129.

• Why it matters: Seed amplification detects αSyn templating competence but loses tissue coordinates, while pS129 immunostaining preserves anatomy without measuring functional seeding activity.
• What they did: The method couples in situ QSAA to multichannel immunolabelling on the same brain section, using mouse αSyn monomer with high sulfate and 70°C quiescent incubation under agarose overlay.
• The result: In preformed-fibril-inoculated mouse brains and human PD tissue, QSAA shows white-matter seeding enrichment, resolves hemispheric asymmetry earlier than pS129, and recovers endogenous seeding signals from archival formalin-fixed PD tissue lacking pS129 immunoreactivity.