TLR2 Recognition of Gut-Derived Fungal and Bacterial D-Alanylated Lipoteichoic Acid Primes Astroglial NFAT/COX-2 Neurotoxicity
🧪 Overview
Dysbiosis permits overgrowth of SIBO species and opportunistic fungi (Candida albicans, Malassezia) whose cell wall components (D-alanyl-LTA, zymosan) are potent TLR2 ligands. TLR2/MyD88 signaling in astrocytes triggers PLA2-dependent arachidonic acid release, upregulating COX-2/PGE2 and NFAT dephosphorylation. This astrocyte 'priming' converts astrocytes from neurotrophic to neurotoxic, producing complement C3 that tags neurons for phagocytosis by hyperactive microglia.
🧬 Mechanism
Curated pathway from expert analysis
flowchart TD
A["TLR2 Activation<br/>Pattern Recognition"]
B["MyD88<br/>Adaptor Protein"]
C["NFATC1<br/>Transcription Factor"]
D["PTGS2 (COX-2)<br/>Prostaglandin Synthesis"]
E["PTGER2 (EP2)<br/>Prostanoid Receptor"]
F["Complement C3<br/>Activation"]
G["Neuroinflammatory<br/>Response"]
H["Synaptic<br/>Dysfunction"]
A --> B
B --> C
C --> D
D --> E
E --> G
F --> G
G --> H
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style H fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a⚖️ Evidence
No linked papers recorded for this hypothesis yet.
🏥 Translation
🧬 3D Protein Structure — TLR2
No curated PDB or AlphaFold mapping for TLR2 yet. Search RCSB →
🧠 GTEx v10 Brain ExpressionJSON
Median TPM across 13 brain regions for TLR2, MyD88, NFATC1, PTGS2 (COX-2), PTGER2 (EP2), C3 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 TLR2, MyD88, NFATC1, PTGS2 (COX-2), PTGER2 (EP2), C3.
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 |
|---|---|---|---|---|
| IF astrocyte-specific MyD88 is genetically deleted (Cx45-Cre;MyD88fl/fl) in adult mice with antibiotic-induced dysbiosis and Candida albicans colonization, THEN astrocyte COX-2 (PTGS2) protein levels | COX-2 (PTGS2) protein expression in GFAP+ astrocytes will be ≥50% lower; nuclear NFATc1+ astrocytes will be ≥40% reduced; cortical C3aR1+ neurons will be ≥35% m | — no observation — | pending | 0.65 |
| IF germ-free C57BL/6J mice are monocolonized with Enterococcus faecalis OG1RF (wild-type, D-alanyl-LTA+) compared to isogenic ΔdltA deletion mutant (lacking D-alanylation), THEN mice colonized with D- | Hippocampal C3 concentration by ELISA will be ≥2-fold elevated; microglial phagocytic index (CD68+/IBA1+ area fraction) will be ≥40% higher; CA1 NeuN+ neuron co | — no observation — | pending | 0.55 |
▸Metadatasource: v1_phase_c_backfill · origin_type: debate_synthesizer
| source | v1_phase_c_backfill |
| origin_type | debate_synthesizer |
| _schema_version | 1 |