Lysosomal Acidification Failure: Convergent GBA1/LAMP2A–mediated Autophagy Dysfunction Links PD and AD Clinical Progression
🧪 Overview
Convergence hypothesis: Lysosomal acidification failure, driven by convergence of GBA1 (PD) and LAMP2A (AD) dysfunction, represents a convergent node in the autophagy-lysosomal pathway that unifies PD and AD progression.
PD-specific mechanism: GBA1 encodes glucocerebrosidase, which hydrolyzes glucosylceramide to ceramide and glucose. In PD, GBA1 mutations (N370S, L444P) reduce enzymatic activity, causing glucosylceramide accumulation that stabilizes α-synuclein oligomers at the lysosomal membrane, blocking autophagosome-lysosome fusion. This impairs clearance of damaged mitochondria (via PINK1/Parkin) and increases exosomal α-synuclein release. LIMP2 (SCARB2) trafficking of GBA1 to lysosomes is also disrupted.
🧬 Mechanism
Curated pathway from expert analysis
flowchart TD
A["GBA1 GCase Loss<br/>GlcCer Accumulation"]
B["LAMP2A CMA Dysfunction<br/>Substrate Translocation Failure"]
C["Lysosomal Acidification Failure<br/>Cathepsin Activity Drops"]
D["Autophagy Lysosomal Bottleneck<br/>SNCA Abeta Tau Clearance Reduced"]
E["TFEB Stress Response<br/>Incomplete Compensation"]
F["PD and AD Clinical Progression<br/>Proteostatic Convergence"]
G["SCARB2 CTSB CTSD Axis<br/>Restoration Target"]
A --> C
B --> C
C --> D
D --> F
E -.->|"attempts rescue"| C
G -.->|"restores"| C
style C fill:#7b1fa2,stroke:#ce93d8,color:#ce93d8
style F fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a⚖️ Evidence
No linked papers recorded for this hypothesis yet.
🏥 Translation
🧬 3D Protein Structure — GBA1
No curated ClinVar variants loaded for this hypothesis.
Run scripts/backfill_clinvar_variants.py to fetch P/LP/VUS variants.
No DepMap CRISPR Chronos data found for GBA1,LAMP2A,SCARB2,CTSB,CTSD,TFEB.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
🏆 Tournament
🏆 Arenas / Elo
📊 Market Indicators
💾 Resource Usage
No resource usage or linked notebooks recorded for this hypothesis yet.
🔮 Predictions
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| Post-mortem PD caudate and AD superior temporal gyrus both show reduced mature cathepsin D (active form) by >60% vs. age-matched controls, with accumulation of pro-cathepsin D. | — | — no observation — | open | 0.80 |
| In GBA1 L444P iPSC-derived neurons, LAMP2A overexpression rescues both α-synuclein (Ser129-P) clearance and mitochondrial complex I activity. | — | — no observation — | open | 0.77 |
▸Metadatasource: v1_phase_c_backfill · origin_type: comparative_synthesis
| source | v1_phase_c_backfill |
| origin_type | comparative_synthesis |
| _schema_version | 1 |