In GBA-associated PD, reduced glucocerebrosidase activity leads to glucosylceramide accumulation in neurons and glia, which directly promotes α-synuclein fibrillization by stabilizing toxic oligomers and disrupting membrane curvature. These α-synuclein aggregates subsequently traffic to the lysosome where they inhibit wild-type GBA activity and impair ER-Golgi trafficking of new GBA enzyme, creating a feedforward loop. I hypothesize that pharmacological restoration of GBA activity using allosteric activators (not chaperones) will preferentially reduce glucosylceramide levels, disrupting this loop and reducing α-synuclein seeding capacity in patient-derived neurons.
Curated pathway from expert analysis
flowchart TD
A["GBA1 Variant<br/>Glucosylceramide Metabolism"]
B["Feedback Loop<br/>GBA-Synuclein Pathology"]
C["Lysosomal<br/>Dysfunction"]
D["Alpha-Synuclein<br/>Aggregation"]
E["GBA1 as<br/>Feedback Loop Target"]
F["Glucosylceramide<br/>Homeostasis Restoration"]
A --> B
B --> C
C --> D
D --> E
E --> F
style A fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
style F fill:#1b5e20,stroke:#a5d6a7,color:#a5d6a7No linked papers recorded for this hypothesis yet.
Median TPM across 13 brain regions for GBA1 from GTEx v10.
No clinical trials data linked to this hypothesis yet.
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.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| IF primary cortical neurons derived from GBA-PD patient iPSCs are treated for 14 days with a selective allosteric GBA activator (not a pharmacological chaperone) at doses sufficient to restore enzyme | Glucosylceramide reduction correlates inversely with α-synuclein seeding capacity; temporal ordering confirms upstream lipid accumulation driving aggregation ra | — no observation — | pending | 0.65 |
| IF cerebrospinal fluid glucosylceramide concentrations are measured and α-synuclein seeding activity is assessed via αSyn-SAA in a cohort of ≥80 GBA-PD patients stratified by genotype severity (severe | Stratified correlation between glucosylceramide and seeding activity specific to GBA-PD genotype severity, supporting glucosylceramide as a quantitative driver | — no observation — | pending | 0.58 |