TBK1 Loss Drives Microglial Senescence-SASP to Generate MMP-9-Mediated TDP-43 C-Terminal Fragments in ALS
🧪 Overview
This hypothesis proposes that TBK1 loss-of-function mutations initiate a pathological cascade where microglia become locked in a senescent state, secreting MMP-9 via the senescence-associated secretory phenotype (SASP), which then generates pathological TDP-43 C-terminal fragments that propagate ALS pathology. The mechanism begins with TBK1 haploinsufficiency disrupting normal microglial homeostasis through impaired NF-κB/IRF3 signaling and defective autophagy, forcing microglia into a senescent, pro-inflammatory state. These senescent microglia then upregulate and secrete MMP-9 as a key SASP component, creating a localized proteolytic environment around motor neurons. The secreted MMP-9 cleaves TDP-43, generating C-terminal fragments that readily aggregate in the cytoplasm and seed further pathological spread. This model explains how genetic TBK1 mutations can initiate ALS pathogenesis through a two-step process: first creating the inflammatory microenvironment via microglial senescence, then generating the specific molecular pathology through MMP-9-mediated TDP-43 fragmentation.
...🧬 Mechanism
Curated pathway from expert analysis
flowchart TD
A["dsDNA/dsRNA or Bacteria<br/>STING/MAVS Signal"]
B["TBK1 Activation<br/>IKK-epsilon Complex"]
C["IRF3 Phosphorylation<br/>Ser396 by TBK1"]
D["IRF3 Dimerization<br/>Nuclear Import"]
E["Type-I IFN Expression<br/>IFN-beta/IFN-alpha"]
F["Antiviral Defense<br/>ISG Upregulation"]
G["TBK1 Loss-of-Function<br/>ALS10 Mutations"]
H["OPTN/p62 Phosphorylation<br/>Selective Autophagy"]
A --> B
B --> C
B --> H
C --> D
D --> E
E --> F
G -.->|"impairs"| B
G -.->|"impairs"| H
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style F fill:#1b5e20,stroke:#81c784,color:#81c784
style G fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a⚖️ Evidence
🏥 Translation
🧬 3D Protein Structure — TBK1
No curated PDB or AlphaFold mapping for TBK1 yet. Search RCSB →
🧠 GTEx v10 Brain ExpressionJSON
Median TPM across 13 brain regions for TBK1 from GTEx v10.
💉 Clinical Trials
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 TBK1.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
🏆 Tournament
🏆 Arenas / Elo
📊 Market Indicators
💾 Resource Usage
▸Metadatasource: v1_phase_c_backfill · origin_type: gap_debate
| source | v1_phase_c_backfill |
| origin_type | gap_debate |
| _schema_version | 1 |