SUMMARY
# Proteasome-Ubiquitin System Dysfunction Validation in Parkinson's Disease
## Background and Rationale
The ubiquitin-proteasome system (UPS) is a critical cellular quality control mechanism responsible for degrading misfolded proteins. Mounting evidence suggests UPS dysfunction plays a pivotal role in Parkinson's disease (PD) pathogenesis, particularly in α-synuclein aggregation and dopaminergic neurodegeneration. This multi-phase translational study aims to validate UPS dysfunction as a primar
METHODOLOGY NOTES
Phase I (Months 1-18): Generate iPSC-derived dopaminergic neurons from 50 PD patients (25 sporadic, 25 familial with SNCA/LRRK2/PRKN mutations) and 25 age-matched controls. Perform UPS activity assays using fluorogenic substrates (Suc-LLVY-AMC), quantify 26S proteasome assembly by native PAGE, and measure ubiquitin chain dynamics via mass spectrometry. Assess α-synuclein aggregation using thioflavin-T binding and immunofluorescence microscopy at 14, 21, and 28 days post-differentiation. Phase II (Months 12-48): Recruit 200 early-stage PD patients (Hoehn-Yahr stage 1-2) and 100 controls for longitudinal biomarker study. Collect CSF and plasma samples every 6 months for 3 years. Quantify proteasome subunit levels (PSMA7, PSMB5), ubiquitin conjugates, and α-synuclein species using ELISA and Simoa assays. Correlate biomarkers with MDS-UPDRS scores, DaTscan results, and cognitive assessments. Phase III (Months 24-42): Test UPS modulators (proteasome activators PA28γ, deubiquitinase inhibito