GPR65 (TDAG8) Modulators for Neurodegeneration

GPR65 (TDAG8) Modulators for Neurodegeneration

Introduction

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">GPR65 (TDAG8) Modulators for Neurodegeneration</th>
</tr>
<tr>
<td class="label">Approach</td>
<td>Development Stage</td>
</tr>
<tr>
<td class="label">Small molecule agonists</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">Positive allosteric modulators</td>
<td>Discovery</td>
</tr>
<tr>
<td class="label">GPR65 gene therapy</td>
<td>Discovery</td>
</tr>
<tr>
<td class="label">Target</td>
<td>GPR65 (TDAG8, GPCR13)</td>
</tr>
<tr>
<td class="label">Drug Class</td>
<td>Proton-sensing GPCR modulator</td>
</tr>
<tr>
<td class="label">Endogenous Ligand</td>
<td>Protons (H⁺)</td>
</tr>
<tr>
<td class="label">Signaling</td>
<td>Gs/Gi-coupled, context-dependent</td>
</tr>
</table>

GPR65, also known as TDAG8 (T-cell death-associated gene 8), is a proton-sensing G-protein coupled receptor that plays crucial roles in immune regulation and cellular homeostasis. Originally identified as a gene induced during T-cell apoptosis, GPR65 is now recognized as an important modulator of neuroinflammation and a potential therapeutic target for neurodegenerative diseases. [@tg2019]

GPR65 Biology

GPR65 is encoded by the [GPR65](/genes/gpr65) gene and belongs to the proton-sensing GPCR family (including GPR4, GPR68, GPR132). Key characteristics include:

GPR65 (TDAG8) Modulators for Neurodegeneration

Introduction

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">GPR65 (TDAG8) Modulators for Neurodegeneration</th>
</tr>
<tr>
<td class="label">Approach</td>
<td>Development Stage</td>
</tr>
<tr>
<td class="label">Small molecule agonists</td>
<td>Preclinical</td>
</tr>
<tr>
<td class="label">Positive allosteric modulators</td>
<td>Discovery</td>
</tr>
<tr>
<td class="label">GPR65 gene therapy</td>
<td>Discovery</td>
</tr>
<tr>
<td class="label">Target</td>
<td>GPR65 (TDAG8, GPCR13)</td>
</tr>
<tr>
<td class="label">Drug Class</td>
<td>Proton-sensing GPCR modulator</td>
</tr>
<tr>
<td class="label">Endogenous Ligand</td>
<td>Protons (H⁺)</td>
</tr>
<tr>
<td class="label">Signaling</td>
<td>Gs/Gi-coupled, context-dependent</td>
</tr>
</table>

GPR65, also known as TDAG8 (T-cell death-associated gene 8), is a proton-sensing G-protein coupled receptor that plays crucial roles in immune regulation and cellular homeostasis. Originally identified as a gene induced during T-cell apoptosis, GPR65 is now recognized as an important modulator of neuroinflammation and a potential therapeutic target for neurodegenerative diseases. [@tg2019]

GPR65 Biology

GPR65 is encoded by the [GPR65](/genes/gpr65) gene and belongs to the proton-sensing GPCR family (including GPR4, GPR68, GPR132). Key characteristics include:

• pH-Sensitive: Activated by extracellular acidosis (pH 6.5-7.0)
• Gs-coupled: Increases cAMP upon activation
• Gi-coupled: In some contexts, inhibits adenylate cyclase
• Immune Cell Expression: High expression in microglia, macrophages, T-cells
• Brain Expression: Detected in hippocampus, cortex, basal ganglia

Mechanism of Action

GPR65 modulators exert neuroprotective effects through acid-sensing and immune modulation:

Key Mechanisms

Therapeutic Potential

Alzheimer's Disease

GPR65 modulators may benefit AD through:

• Reduction of chronic neuroinflammation
• Protection of hippocampal neurons
• Modulation of microglial phagocytosis
• Potential effects on amyloid clearance

Parkinson's Disease

GPR65 is particularly relevant for PD:

• High expression in substantia nigra
• Protection of dopaminergic neurons
• Reduction of neuroinflammation in basal ganglia
• Potential for disease modification [@ry2021]

Other Neurodegenerative Conditions

• [Amyotrophic Lateral Sclerosis](/diseases/amyotrophic-lateral-sclerosis)
• [Multiple Sclerosis](/diseases/multiple-sclerosis)
• Stroke and traumatic brain injury

Drug Development

GPR65 modulators are in early development. Key approaches include:

Drug Properties

Research Status

GPR65 remains an emerging target. Key challenges include:

• Developing brain-penetrant compounds
• Understanding context-dependent signaling
• Species differences in receptor function
• Limited knowledge of endogenous ligands beyond protons

References

Related Pages

• [GPCR Modulators](/therapeutics/metabotropic-glutamate-receptor-modulator-therapy)
• [Microglial Modulation](/therapeutics/microglial-modulation-therapy-neurodegeneration)
• [Neuroinflammation](/therapeutics/neuroinflammation-modulation-therapies)
• [GPR65 Gene](/genes/gpr65)

Related Hypotheses

From the [SciDEX Exchange](/exchange) — scored by multi-agent debate

• [Nutrient-Sensing Epigenetic Circuit Reactivation](/hypothesis/h-4bb7fd8c) — <span style="color:#81c784;font-weight:600">0.79</span> · Target: SIRT1
• [CYP46A1 Overexpression Gene Therapy](/hypothesis/h-2600483e) — <span style="color:#81c784;font-weight:600">0.79</span> · Target: CYP46A1
• [Circadian Glymphatic Entrainment via Targeted Orexin Receptor Modulation](/hypothesis/h-9e9fee95) — <span style="color:#81c784;font-weight:600">0.77</span> · Target: HCRTR1/HCRTR2
• [Selective Acid Sphingomyelinase Modulation Therapy](/hypothesis/h-de0d4364) — <span style="color:#81c784;font-weight:600">0.77</span> · Target: SMPD1
• [Membrane Cholesterol Gradient Modulators](/hypothesis/h-9d29bfe5) — <span style="color:#81c784;font-weight:600">0.76</span> · Target: ABCA1/LDLR/SREBF2
• [Microbial Inflammasome Priming Prevention](/hypothesis/h-e7e1f943) — <span style="color:#81c784;font-weight:600">0.76</span> · Target: NLRP3, CASP1, IL1B, PYCARD
• [Blood-Brain Barrier SPM Shuttle System](/hypothesis/h-959a4677) — <span style="color:#81c784;font-weight:600">0.75</span> · Target: TFRC
• [Purinergic Signaling Polarization Control](/hypothesis/h-0758b337) — <span style="color:#81c784;font-weight:600">0.74</span> · Target: P2RY1 and P2RX7

Related Analyses:

• [Synaptic pruning by microglia in early AD](/analysis/SDA-2026-04-01-gap-v2-691b42f1) &#x1f504;
• [SEA-AD Gene Expression Profiling — Allen Brain Cell Atlas](/analysis/analysis-SEAAD-20260402) &#x1f504;
• [APOE4 structural biology and therapeutic targeting strategies](/analysis/SDA-2026-04-01-gap-010) &#x1f504;
• [Senescent cell clearance as neurodegeneration therapy](/analysis/SDA-2026-04-02-gap-senescent-clearance-neuro) &#x1f504;
• [4R-tau strain-specific spreading patterns in PSP vs CBD](/analysis/SDA-2026-04-01-gap-005) &#x1f504;