ID: h-da6c36b942
Hypothesis

Direct cystatin C inhibition of tau aggregation

Cystatin C binds tau through its cystatin-like domain, sequestering monomeric tau and preventing β-sheet aggregation.
🧬 CST3/MAPT interaction🩺 neurodegeneration🎯 Composite 39%💱 $0.47▲15.3%proposed
EvidencePending (0%)📖 0 cit🗣 1 debates 7 support 3 oppose
✓ All Quality Gates Passed
Mechanistic 0.28 (15%) Evidence 0.30 (15%) Novelty 0.55 (12%) Feasibility 0.30 (12%) Impact 0.45 (12%) Druggability 0.25 (10%) Safety 0.60 (8%) Competition 0.65 (6%) Data Avail. 0.35 (5%) Reproducible 0.22 (5%) KG Connect 0.50 (8%) 0.390 composite

🧪 Overview

Cystatin C binds tau through its cystatin-like domain, sequestering monomeric tau and preventing β-sheet aggregation. This hypothesis has the weakest mechanistic foundation: cystatin C is secreted (extracellular) while tau is predominantly intracellular. The 2005 Co-IP has not been independently replicated in 20+ years. At physiologically relevant concentrations (10-50 nM CSF), any inhibitory effect may be negligible.

🧬 Mechanism

🧬 Curated Mechanism Pathway

Curated pathway from expert analysis

flowchart TD
    A["Glymphatic Dysfunction<br/>Sleep Disruption and AQP4 Depolarization"]
    B["Impaired ISF-CSF Exchange<br/>Perivascular Clearance Failure"]
    C["Tau Accumulation<br/>MAPT-Encoded Tau Aggregation"]
    D["Tau Seeding and Spreading<br/>Prion-like Trans-neuronal Propagation"]
    E["Neurodegeneration<br/>Synaptic Loss and Cognitive Decline"]
    F["Glymphatic Enhancement<br/>Sleep Optimization or Norepinephrine Reduction"]
    A --> B
    B --> C
    C --> D
    D --> E
    F -.->|"restores"| B
    style A fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
    style C fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
    style E fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
    style F fill:#1b5e20,stroke:#81c784,color:#81c784

⚖️ Evidence

⚖️ Evidence Matrix7 supports3 contradicts
Supports
Cystatin C co-immunoprecipitates with tau in human brain tissue (unreplicated)
Supports
CST3 polymorphisms associate with differential AD risk in some meta-analyses
Supports
Biochemical analyses of cystatin-C dimers and cathepsin-B reveals a trypsin-driven feedback mechanism in acute pancreatitis.
Nat Commun2025PMID:39962054
Supports
Cystatin inhibition of cathepsin B requires dislocation of the proteinase occluding loop. Demonstration By release of loop anchoring through mutation of his110.
FEBS Lett2000PMID:11150500
Supports
Structural basis for the biological specificity of cystatin C. Identification of leucine 9 in the N-terminal binding region as a selectivity-conferring residue in the inhibition of mammalian cysteine peptidases.
J Biol Chem1995PMID:7890620
Supports
Importance of the evolutionarily conserved glycine residue in the N-terminal region of human cystatin C (Gly-11) for cysteine endopeptidase inhibition.
Biochem J1993PMID:8471031
Supports
Structural basis for different inhibitory specificities of human cystatins C and D.
Biochemistry1998PMID:9521728
Contradicts
Localization paradox: extracellular cystatin C vs intracellular tau
Contradicts
Co-IP not independently replicated in 20+ years
Contradicts
Species conservation mismatch suggests species-specific artifact
📖 Linked Papers

No linked papers recorded for this hypothesis yet.

🏥 Translation

🧬 3D Protein Structure — CST3

No curated PDB or AlphaFold mapping for CST3 yet. Search RCSB →

🧠 GTEx v10 Brain ExpressionJSON

Median TPM across 13 brain regions for CST3/MAPT interaction from GTEx v10.

Amygdala685 Putamen basal ganglia680 Caudate basal ganglia655 Cortex611 Frontal Cortex BA9583 Anterior cingulate cortex BA24529 Substantia nigra502 Hippocampus480 Nucleus accumbens basal ganglia447 Cerebellum350 Hypothalamus335 Cerebellar Hemisphere273 Spinal cord cervical c-1268median TPM (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.

🔍 Search ClinVar for CST3 →

No DepMap CRISPR Chronos data found for CST3.

Run python3 scripts/backfill_hypothesis_depmap.py to populate.

💰 Estimated Development
Cost
$0
Timeline

🏆 Tournament

🏆 Arenas / Elo

No arena matches recorded yet. Browse Arenas →

📊 Market Indicators

7d Trend
Stable
7d Momentum
▲ 0.6%
Volatility
Medium
0.0227
Events (7d)
2
Price History
▲15.3%

💾 Resource Usage

LLM Tokens
11,154
$0.0335
Total Cost
$0.0335

🔮 Predictions

🔎 Predictions vs Observations2 predictions · 0 with recorded observations
PredictionPredictedObservedStatusConf
IF full-length human CST3 is overexpressed intracellularly at 3-fold above endogenous levels in HEK293T cells engineered to aggregate tau (FRET-based biosensor line), THEN tau aggregate burden will deFRET signal reduction of >25% indicating decreased tau aggregation, with cell viability unchanged— no observation —pending0.05
IF recombinant human CST3 is added at 10-50 nM (physiological CSF concentration) to in vitro Thioflavin-T tau aggregation assays with recombinant MAPT (2N4R), THEN ThT fluorescence will be reduced by Significant reduction in tau fibril formation with ThT fluorescence decreasing by >30% relative to control— no observation —pending0.10
🔮 Falsifiable Predictions (2)
pendingconf 10%
IF recombinant human CST3 is added at 10-50 nM (physiological CSF concentration) to in vitro Thioflavin-T tau aggregation assays with recombinant MAPT (2N4R), THEN ThT fluorescence will be reduced by >30% compared to vehicle control within 48 hours.
Predicted outcome: Significant reduction in tau fibril formation with ThT fluorescence decreasing by >30% relative to control
Falsification: No significant reduction in ThT fluorescence (<20% change) or ThT signal unchanged/increased after CST3 treatment
pendingconf 5%
IF full-length human CST3 is overexpressed intracellularly at 3-fold above endogenous levels in HEK293T cells engineered to aggregate tau (FRET-based biosensor line), THEN tau aggregate burden will decrease by >25% within 72 hours post-transfection.
Predicted outcome: FRET signal reduction of >25% indicating decreased tau aggregation, with cell viability unchanged
Falsification: FRET signal unchanged or increased (<10% change), or filter trap assay shows no reduction in insoluble tau; no change in phosphorylation state (AT8, AT180)
Metadatasource: v1_phase_c_backfill · origin_type: debate_synthesizer
sourcev1_phase_c_backfill
origin_typedebate_synthesizer
_schema_version1
📊 Evidence Profile
Evidence Balance
+0%
Certainty
0%
Debates
0
Incoming
0
Outgoing
0
0 supporting 0 contradicting 0 neutral
Public annotations (0)Annotate on Hypothes.is →
No public annotations yet.