Healthy astrocytes secrete GDNF, which activates RET receptor signaling on motor neurons, promoting microtubule-dependent transport of RNA-binding proteins and preventing TDP-43 mislocalization. Hypoxic/ALS astrocytes show decreased GDNF secretion, disrupting this protective axis. However, this hypothesis is weakly anchored to the specific RBP-localization phenotype in the VCP/hypoxia system and faces substantial delivery challenges for translation.
Curated pathway from expert analysis
flowchart TD
A["VCP/p97 AAA+ ATPase<br/>CHIP-Dependent Degradation Complex"]
B["ER-Associated Degradation (ERAD)<br/>Ubiquitinated Substrate Extraction"]
C["AGFG1 and ArfGAP1 Interaction<br/>Vesicle Trafficking and Autophagosome Maturation"]
D["TDP-43 and FUS Extraction<br/>Nuclear Quality Control Failure Compensation"]
E["VCP Mutation (Multisystem Proteinopathy)<br/>Degeneration of Neurons and Muscle"]
F["Inclusion Body Myopathy and Frontotemporal Dementia<br/>Pathologic Aggregate Accumulation"]
G["VCP Inhibitor Therapeutic Strategy<br/>Preclinical Validation Needed"]
A --> B
B --> C
C --> D
E --> F
F --> G
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style F fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
style G fill:#1b5e20,stroke:#81c784,color:#81c784No linked papers recorded for this hypothesis yet.
No curated PDB or AlphaFold mapping for GDNF; yet. Search RCSB →
Median TPM across 13 brain regions for GDNF; RET; VCP 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 GDNF; RET; VCP.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| IF human iPSC-derived motor neurons are co-cultured with hypoxic preconditioned astrocytes (2% O2, 48h) AND exogenous GDNF (100 ng/mL) is added to the culture medium, THEN TDP-43 nuclear localization | TDP-43 nuclear/cytoplasmic ratio will be ≥0.70 in GDNF-treated hypoxic co-cultures vs. ≤0.50 in untreated hypoxic co-cultures, as measured by immunofluorescence | — no observation — | pending | 0.55 |
| IF primary murine spinal motor neurons are treated with the selective RET inhibitor RPI-1 (10 μM) or RET-targeted siRNA for 48 hours, THEN TDP-43 mislocalization (cytoplasmic accumulation) will increa | Cytoplasmic TDP-43 intensity will increase to ≥1.5-fold relative to nuclear TDP-43 in RET-inhibited neurons, with ≥50% reduction in p-ERK1/2/total ERK ratio, as | — no observation — | pending | 0.48 |