ID: h-cc60dcd54d
Hypothesis

H2S/butyrate imbalance drives enteric alpha-synuclein pathology via TLR4 signaling

In Parkinson's disease, elevated H2S-producing Desulfovibrio species and depleted butyrate-producing Faecalibacterium prausnitzii create a metabolite imbalance that simultaneously disrupts gut barrier integrity and increases systemic LPS.
🧬 SNCA🩺 parkinsons🎯 Composite 38%💱 $0.53▲10.1%proposed
EvidencePending (0%)📖 5 cit🗣 1 debates 5 support 2 oppose
Mechanistic 0.72 (15%) Evidence 0.72 (15%) Novelty 0.78 (12%) Feasibility 0.82 (12%) Impact 0.00 (12%) Druggability 0.00 (10%) Safety 0.00 (8%) Competition 0.00 (6%) Data Avail. 0.00 (5%) Reproducible 0.00 (5%) KG Connect 0.35 (8%) 0.380 composite

🧪 Overview

In Parkinson's disease, elevated H2S-producing Desulfovibrio species and depleted butyrate-producing Faecalibacterium prausnitzii create a metabolite imbalance that simultaneously disrupts gut barrier integrity and increases systemic LPS translocation. The resulting TLR4 activation on enteric neurons triggers NF-κB-mediated neuroinflammation, promoting local alpha-synuclein misfoldling and aggregation. This enteric pathology then propagates bidirectionally along the vagus nerve to the dorsal motor nucleus and from autonomic ganglia to peripheral neurons, representing the gut-first progression of PD. Fecal transplant to germ-free α-synuclein transgenic mice will test whether disease-specific microbial communities are sufficient to induce enteric protein aggregation and whether Desulfovibrio colonization alone reproduces the pathological phenotype.

🧬 Mechanism

🧬 Curated Mechanism Pathway

Curated pathway from expert analysis

flowchart TD
    A["H2S/Butyrate<br/>Imbalance"]
    B["Gut Barrier<br/>Dysfunction"]
    C["TLR4 Signaling<br/>Neuroinflammation"]
    D["SNCA Expression<br/>Alpha-Synuclein"]
    E["Enteric Alpha-Synuclein<br/>Pathology"]
    F["Gut-Brain TLR4 Axis<br/>as Therapeutic Target"]
    A --> B
    B --> C
    C --> D
    D --> E
    E --> F
    style A fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
    style F fill:#1b5e20,stroke:#a5d6a7,color:#a5d6a7

⚖️ Evidence

⚖️ Evidence Matrix5 supports2 contradicts
Supports
Monogenic Parkinson's Disease: Genotype, Phenotype, Pathophysiology, and Genetic Testing.
Genes (Basel)2022PMID:35328025medium
Supports
SNCA REP1 and Parkinson's disease.
Neurosci Lett2018PMID:29859327medium
Supports
Parkinson's disease - genetic cause.
Curr Opin Neurol2023PMID:37366140medium
Supports
SNCA-AS1 in aging and Parkinson's disease.
Aging (Albany NY)2022PMID:35438650medium
Supports
Mitochondria and Parkinson's Disease: Clinical, Molecular, and Translational Aspects.
J Parkinsons Dis2021PMID:33074190medium
Contradicts
Strain-specific effects of Desulfovibrio on neurodegeneration show that not all H2S-producing Desulfovibrio strains enhance alpha-synuclein aggregation equally; the variability in outcomes indicates that factors beyond H2S production (e.g. specific lipopolysaccharide structures) are responsible, challenging the H2S-centric mechanism
Contradicts
TLR4/NF-κB neuroinflammation from gut dysbiosis in Parkinson's is activated more potently by bacterial lipopolysaccharides than by H2S; the proposed H2S/butyrate balance as the primary TLR4 driver is not experimentally distinguished from co-occurring LPS-mediated activation in PD gut microbiome studies
📖 Linked Papers

No linked papers recorded for this hypothesis yet.

🏥 Translation

🧬 3D Protein Structure — SNCA

🧬 PDB 1XQ8 Click to expand

Experimental structure from RCSB PDB | Powered by Mol*

🧠 GTEx v10 Brain ExpressionJSON

Median TPM across 13 brain regions for SNCA from GTEx v10.

Cerebellar Hemisphere61.9 Frontal Cortex BA959.1 Anterior cingulate cortex BA2447.5 Cerebellum44.6 Cortex36.0 Spinal cord cervical c-125.7 Amygdala24.9 Nucleus accumbens basal ganglia21.6 Substantia nigra20.8 Hippocampus19.0 Hypothalamus18.5 Caudate basal ganglia13.5 Putamen basal ganglia12.4median TPM (GTEx v10)

💉 Clinical Trials

No clinical trials data linked to this hypothesis yet.

No curated ClinVar variants loaded for this hypothesis.

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📊 Market Indicators

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💾 Resource Usage

No resource usage or linked notebooks recorded for this hypothesis yet.

🔮 Predictions

🔎 Predictions vs Observations2 predictions · 0 with recorded observations
PredictionPredictedObservedStatusConf
IF germ-free α-synuclein transgenic (Thy1-αSyn) mice are colonized with H2S-producing Desulfovibrio vulgaris ATCC 29579, THEN intestinal p-S129 α-synuclein accumulation will increase by ≥50% in enteriIncreased p-S129 α-synuclein immunoreactivity (≥50% change) in myenteric and submucosal plexuses, measured by quantitative immunohistochemistry with stereologic— no observation —pending0.72
IF butyrate-producing Faecalibacterium prausnitzii A2-165 is co-administered with Desulfovibrio vulgaris to germ-free α-synuclein transgenic mice, THEN fecal LPS activity and intestinal TLR4 downstreaFecal LPS activity reduced by ≥60% and ileal p-NF-κB p65/β-actin ratio reduced to baseline (germ-free) levels, measured by Limulus amebocyte lysate assay and we— no observation —pending0.68
🔮 Falsifiable Predictions (2)
pendingconf 72%
IF germ-free α-synuclein transgenic (Thy1-αSyn) mice are colonized with H2S-producing Desulfovibrio vulgaris ATCC 29579, THEN intestinal p-S129 α-synuclein accumulation will increase by ≥50% in enteric neurons of the ileum and colon compared to germ-free controls within 12 weeks post-colonization.
Predicted outcome: Increased p-S129 α-synuclein immunoreactivity (≥50% change) in myenteric and submucosal plexuses, measured by quantitative immunohistochemistry with s
Falsification: No significant difference (p > 0.05) in intestinal p-S129 α-synuclein burden between Desulfovibrio-colonized and germ-free mice after 12 weeks, or reduction rather than increase in aggregated α-synucl
pendingconf 68%
IF butyrate-producing Faecalibacterium prausnitzii A2-165 is co-administered with Desulfovibrio vulgaris to germ-free α-synuclein transgenic mice, THEN fecal LPS activity and intestinal TLR4 downstream signaling (p-NF-κB p65) will decrease to levels comparable to Faecalibacterium-only colonized mice
Predicted outcome: Fecal LPS activity reduced by ≥60% and ileal p-NF-κB p65/β-actin ratio reduced to baseline (germ-free) levels, measured by Limulus amebocyte lysate as
Falsification: Co-colonization with F. prausnitzii fails to reduce fecal LPS activity or intestinal NF-κB activation below Desulfovibrio-only levels (p > 0.05 for group comparison), indicating butyrate does not anta
Metadatasource: v1_phase_c_backfill · origin_type: audit_hypothesis_generator
sourcev1_phase_c_backfill
origin_typeaudit_hypothesis_generator
_schema_version1
📊 Evidence Profile
Evidence Balance
+0%
Certainty
0%
Debates
0
Incoming
0
Outgoing
0
0 supporting 0 contradicting 0 neutral
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