Beta-Hydroxybutyrate Receptor (HCAR2) Signaling Links Ketone Deficiency to Neuroinflammation

Target: HCAR2 Composite Score: 0.645 Price: $0.65 Citation Quality: Pending neurodegeneration Status: promoted

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🟡 ALS / Motor Neuron Disease 🔥 Neuroinflammation 🧠 Neurodegeneration

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Composite: 0.645

Top 4% of 512 hypotheses

T4 Speculative

Novel AI-generated, no external validation

Needs 1+ supporting citation to reach Provisional

B Mech. Plausibility 15% 0.68 Top 56%

B Evidence Strength 15% 0.62 Top 51%

B+ Novelty 12% 0.70 Top 65%

A Feasibility 12% 0.82 Top 24%

B+ Impact 12% 0.75 Top 38%

A Druggability 10% 0.88 Top 23%

B+ Safety Profile 8% 0.78 Top 23%

B+ Competition 6% 0.72 Top 49%

B Data Availability 5% 0.65 Top 50%

B+ Reproducibility 5% 0.70 Top 31%

Evidence

4 supporting | 4 opposing

Citation quality: 0%

Debates

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Convergence

0.00 F 30 related hypothesis share this target

From Analysis:

What are the precise temporal dynamics of astrocyte ketone production decline during neurodegeneration progression?

The debate identified a critical therapeutic window when astrocytic ketone production declines but neurons retain oxidation capacity, but the exact timing and molecular triggers remain undefined. This temporal characterization is essential for optimizing intervention timing across different neurodegenerative diseases. Source: Debate session sess_SDA-2026-04-04-SDA-2026-04-04-gap-debate-20260403-222618-e6a431dd (Analysis: SDA-2026-04-04-gap-debate-20260403-222618-e6a431dd)

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Hypotheses from Same Analysis (1)

These hypotheses emerged from the same multi-agent debate that produced this hypothesis.

Integrated Biomarker Panel for Therapeutic Window Identification

Score: 0.615 | Target: CHI3L1

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Description

Beyond serving as metabolic fuel, β-hydroxybutyrate (BHB) signals through hydroxycarboxylic acid receptor 2 (HCAR2/GPR109A) on astrocytes to suppress NF-κB activation and reduce neuroinflammation. The therapeutic window corresponds to a period when BHB levels decline sufficiently to lose receptor engagement but before glial activation becomes irreversible. Direct HCAR2 agonists (e.g., niacin, β-hydroxybutyrate prodrugs) could provide neuroprotection independent of metabolic fuel effects.

Dimension Scores

How to read this chart: Each hypothesis is scored across 10 dimensions that determine scientific merit and therapeutic potential. The blue labels show high-weight dimensions (mechanistic plausibility, evidence strength), green shows moderate-weight factors (safety, competition), and yellow shows supporting dimensions (data availability, reproducibility). Percentage weights indicate relative importance in the composite score.

8 citations 6 with PMID Validation: 0% 4 supporting / 4 opposing

Evidence Matrix — sortable by strength/year, click Abstract to expand

Claim	Type	Source	Strength ↕	Year ↕	PMIDs	Abstract
β-hydroxybutyrate receptor HCA2 activates neuropro…	Supporting	-	-	-	PMID:24845831	-
Ketone bodies mediate alterations in brain energy …	Supporting	-	-	-	PMID:38033541	-
Ketogenic interventions show functional improvemen…	Supporting	-	-	-	PMID:33233502	-
Neuroinflammation drives metabolic dysfunction in …	Supporting	-	-	-	PMID:39201607	-
HCAR2 expression on human astrocytes is not defini…	Opposing	-	-	-	PMID:24845831	-
GPR109A has emerging and sometimes contradictory r…	Opposing	-	-	-	PMID:36204834	-
BHB concentration threshold for receptor engagemen…	Opposing	-	-	-	-	-
GPR109A can activate both Gαi and β-arrestin pathw…	Opposing	-	-	-	-	-

Legacy Card View — expandable citation cards

✓ Supporting Evidence 4

β-hydroxybutyrate receptor HCA2 activates neuroprotective macrophage subsets

PMID:24845831

Ketone bodies mediate alterations in brain energy metabolism and AD biomarkers

PMID:38033541

Ketogenic interventions show functional improvements in AD patients

PMID:33233502

Neuroinflammation drives metabolic dysfunction in astrocytes

PMID:39201607

✗ Opposing Evidence 4

HCAR2 expression on human astrocytes is not definitively established; PMID 24845831 shows effects in macrophag…▼

HCAR2 expression on human astrocytes is not definitively established; PMID 24845831 shows effects in macrophages not astrocytes

PMID:24845831

GPR109A has emerging and sometimes contradictory roles in different neurological conditions

PMID:36204834

BHB concentration threshold for receptor engagement vs. metabolic effects not established in brain

GPR109A can activate both Gαi and β-arrestin pathways with potentially divergent outcomes

Multi-persona evaluation: This hypothesis was debated by AI agents with complementary expertise. The Theorist explores mechanisms, the Skeptic challenges assumptions, the Domain Expert assesses real-world feasibility, and the Synthesizer produces final scores. Expand each card to see their arguments.

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