Astrocytes play a critical role in synaptic pruning and maintenance of neural circuits through complement-mediated elimination of weak or aberrant synaptic connections. This hypothesis proposes that targeted activation of astrocytic complement cascade, specifically through C1q upregulation and subsequent C3 tagging of synapses, can restore optimal functional connectivity patterns in disrupted neural networks. Unlike structural remyelination approaches, this mechanism focuses on refining existing synaptic architecture by selectively eliminating maladaptive connections while preserving or strengthening functionally relevant pathways. Astrocytes would identify synapses for elimination through activity-dependent monitoring of synaptic strength and frequency, using their extensive processes that contact multiple synapses simultaneously. The intervention would involve pharmacological or optogenetic activation of astrocytic complement pathways, particularly targeting the C1q-C3-microglia axis, to enhance pruning efficiency in regions showing aberrant hyperconnectivity or maintaining weak connections that impair network function.
...Curated pathway from expert analysis
flowchart TD
A["Astrocyte C1Q<br/>Complement Expression"]
B["C1qa C1qb C1qc<br/>Subcomponent Assembly"]
C["Synaptic C3 Fragment<br/>Tagging"]
D["Microglial Phagocytosis<br/>Recognition and Engulfment"]
E["Synaptic Pruning<br/>Connectome Remodeling"]
F["Functional Optimization<br/>Efficiency Gain"]
G["Excessive Pruning<br/>as Pathological Driver"]
A --> B
B --> C
C --> D
D --> E
E --> F
G -.->|"risk"| E
style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
style G fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
style F fill:#1b5e20,stroke:#a5d6a7,color:#a5d6a7No linked papers recorded for this hypothesis yet.
No curated PDB or AlphaFold mapping for C1Q yet. Search RCSB →
Median TPM across 13 brain regions for C1q 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 C1q.
Run python3 scripts/backfill_hypothesis_depmap.py to populate.
| Prediction | Predicted | Observed | Status | Conf |
|---|---|---|---|---|
| IF we selectively upregulate astrocytic C1q expression using AAV-GfaABC1D-C1q viral vectors in the prefrontal cortex of adult Cntnap2−/− mice (an autism-related hyperconnectivity model), THEN we will | Synaptic density will decrease by 15-25% in the prefrontal cortex, accompanied by normalized functional connectivity patterns including reduced hyperconnectivit | — no observation — | pending | 0.65 |
| IF we apply pharmacological C1q pathway activation (small-molecule agonist) to human iPSC-derived cortical organoids co-cultured with iPSC-derived microglia, THEN synaptic pruning efficiency will incr | Enhanced complement-mediated synaptic pruning will result in preferential elimination of weak synapses (lower PSD95 intensity), increased microglia-synapse cont | — no observation — | pending | 0.55 |