GPR37 Modulator Therapy for Parkinson's Disease

GPR37 Modulator Therapy for Parkinson's Disease

Overview

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">GPR37 Modulator Therapy for Parkinson's Disease</th>
</tr>
<tr>
<td class="label">Target</td>
<td>Example</td>
</tr>
<tr>
<td class="label">D2/D3 dopamine</td>
<td>Pramipexole</td>
</tr>
<tr>
<td class="label">Adenosine A2A</td>
<td>Istradefylline</td>
</tr>
<tr>
<td class="label">GPR6</td>
<td>CVN424</td>
</tr>
<tr>
<td class="label">GPR37</td>
<td>Various</td>
</tr>
</table>

[GPR37](/cell-types/gpr37-neurons) (G protein-coupled receptor 37, also known as PAELR — PARKIN-associated endothelin receptor-like 1) is an orphan GPCR with direct genetic links to [Parkinson's disease](/diseases/parkinsons-disease). Mutations in GPR37 cause autosomal recessive juvenile parkinsonism, and polymorphisms in GPR37 are associated with sporadic PD risk[@kelm2022]. Therapeutic strategies targeting GPR37 include agonists to promote neuroprotective signaling, antagonists to block pathogenic ER stress, and chaperone therapies to correct misfolded GPR37. The cell-type page for [GPR37 neurons](/cell-types/gpr37-neurons) provides detailed biology; this page focuses on the therapeutic landscape.

GPR37 Biology and PD Connection

Genetic Link to Parkinson's Disease

GPR37 is one of a small number of GPCRs with direct genetic causation in parkinsonism[@marazziti2024]:

GPR37 Modulator Therapy for Parkinson's Disease

Overview

<table class="infobox infobox-therapeutic">
<tr>
<th class="infobox-header" colspan="2">GPR37 Modulator Therapy for Parkinson's Disease</th>
</tr>
<tr>
<td class="label">Target</td>
<td>Example</td>
</tr>
<tr>
<td class="label">D2/D3 dopamine</td>
<td>Pramipexole</td>
</tr>
<tr>
<td class="label">Adenosine A2A</td>
<td>Istradefylline</td>
</tr>
<tr>
<td class="label">GPR6</td>
<td>CVN424</td>
</tr>
<tr>
<td class="label">GPR37</td>
<td>Various</td>
</tr>
</table>

[GPR37](/cell-types/gpr37-neurons) (G protein-coupled receptor 37, also known as PAELR — PARKIN-associated endothelin receptor-like 1) is an orphan GPCR with direct genetic links to [Parkinson's disease](/diseases/parkinsons-disease). Mutations in GPR37 cause autosomal recessive juvenile parkinsonism, and polymorphisms in GPR37 are associated with sporadic PD risk[@kelm2022]. Therapeutic strategies targeting GPR37 include agonists to promote neuroprotective signaling, antagonists to block pathogenic ER stress, and chaperone therapies to correct misfolded GPR37. The cell-type page for [GPR37 neurons](/cell-types/gpr37-neurons) provides detailed biology; this page focuses on the therapeutic landscape.

GPR37 Biology and PD Connection

Genetic Link to Parkinson's Disease

GPR37 is one of a small number of GPCRs with direct genetic causation in parkinsonism[@marazziti2024]:

• Mendelian mutations: GPR37 loss-of-function mutations cause autosomal recessive juvenile parkinsonism with features resembling [ PARK2 (PARKIN) mutations](/proteins/parkin-protein)
• Association with sporadic PD: GPR37 polymorphisms are associated with altered PD risk in genome-wide association studies[@liu2021]
• Co-localization with PARKIN: GPR37 physically interacts with PARKIN, the E3 ubiquitin ligase mutated in the second most common form of familial PD

Pathophysiology

In [dopaminergic neurons](/cell-types/nigrostriatal-dopamine-neurons) of the [substantia nigra pars compacta](/cell-types/substantia-nigra-pars-compacta-dopamine-neurons), GPR37 dysfunction drives neurodegeneration through several interconnected mechanisms[@zhang2023][@wang2023]:

Receptor Pharmacology

GPR37 has unusual pharmacological properties[@kelm2022]:

• Orphan receptor: Despite structural similarity to endothelin receptors, no definitive endogenous ligand has been established
• Constitutively active: Exhibits baseline signaling activity independent of ligand
• G protein coupling: Primarily Gi/Go-coupled, inhibiting adenylate cyclase
• β-arrestin pathway: Signals through β-arrestin-dependent mechanisms independent of G proteins
• ER retention: Mutant GPR37 is retained in the ER, causing cellular stress

Therapeutic Strategies

GPR37 Agonists

Mechanism: GPR37 agonists activate pro-survival signaling pathways in dopaminergic neurons[@kelm2022]:

• PI3K/Akt pathway activation: Promotes neuronal survival and protects against toxin-induced cell death
• BDNF modulation: Enhances brain-derived neurotrophic factor signaling
• Anti-apoptotic signaling: Activates survival pathways including MAPK/ERK
• Glutathione regulation: Supports oxidative stress response

GPR37 Antagonists

Mechanism: GPR37 antagonists block the pathogenic signaling from accumulated/misfolded GPR37[@zhang2023]:

• Reduce ER stress markers: Lower CHOP, ATF4, and other UPR pathway activation
• Block calcium dysregulation: Reduce ER calcium release and mitochondrial calcium overload
• Inhibit pro-apoptotic signaling: Prevent caspase activation from ER stress pathways

GPR37 Chaperone Therapy

Mechanism: Small molecule chaperones promote proper folding of misfolded GPR37, preventing ER retention and aggregation[@thompson2020]:

• ER folding rescue: Assist native GPR37 folding, reducing ER stress
• Protein quality control: Redirect misfolded GPR37 toward productive folding rather than ER-associated degradation (ERAD)
• Restored cell surface expression: Chaperone-treated GPR37 reaches the cell surface where it can participate in normal signaling

PARKIN Activators

Mechanism: Since GPR37 is a PARKIN substrate, restoring PARKIN function addresses the root cause of GPR37 accumulation[@marazziti2024]:

• Promote PARKIN activation: Small molecules that activate PARKIN E3 ligase activity
• Enhance mitophagy: Restore PINK1-PARKIN mitophagy pathway
• GPR37 ubiquitination: Enable proper degradation of GPR37

Comparison with Other GPCR-Targeted PD Therapies

GPR37 therapy stands out as a disease-modifying approach focused on neuroprotection and addressing genetic causes, rather than symptomatic motor control. It shares the non-dopaminergic advantage of GPR6 targeting but with a more fundamental neuroprotective rather than circuit-modulating mechanism.

GPR37 in iPSC Models

Human [iPSC](/technologies/ipsc-therapy-neurodegeneration)-derived dopaminergic neurons from patients with GPR37 mutations have been used to model the disease and test therapeutic candidates[@kelm2022]:

• ER stress readouts: Pharmacological chaperones reduce markers of ER stress (GRP78/BiP, CHOP) in patient neurons
• Rescue of mitochondrial dysfunction: PARKIN activator strategies restore mitophagy flux
• Alpha-synuclein aggregation: GPR37 dysfunction synergizes with [alpha-synuclein](/proteins/alpha-synuclein) pathology, suggesting combined targeting strategies
• Drug screening: High-content imaging of patient neurons enables medium-throughput screening of GPR37-modulating compounds

Cross-References

Related Mechanisms and Pathways

• [Parkin's Role in Mitochondrial Quality Control](/mechanisms/parkin-mitophagy-pathway)
• [ER Stress and the Unfolded Protein Response in Neurodegeneration](/mechanisms/er-stress-pathway)
• [Alpha-Synuclein Aggregation Pathway](/mechanisms/alpha-synuclein-pathway)
• [Nigrostriatal Dopamine Neuron Vulnerability](/mechanisms/nigrostriatal-dopamine-pathway)
• [Protein Quality Control in Neurodegeneration](/mechanisms/protein-quality-control-network)

Related Cell Types

• [GPR37 Neurons](/cell-types/gpr37-neurons)
• [Nigrostriatal Dopamine Neurons](/cell-types/nigrostriatal-dopamine-neurons)

Related Therapeutic Pages

• [GPR6 Modulator Therapy for Parkinson's Disease](/therapeutics/gpr6-modulator-therapy-parkinsons)
• [Dopamine Agonist Therapy for Parkinson's Disease](/therapeutics/dopamine-agonists)
• [Adenosine A2A Receptor Antagonists for Parkinson's Disease](/therapeutics/adenosine-a2a-antagonists)
• [Neurotrophic Factor Therapies for Parkinson's Disease](/therapeutics/neurotrophic-factor-therapy)
• [Alpha-Synuclein Immunotherapy for Parkinson's Disease](/therapeutics/alpha-synuclein-immunotherapy-parkinsons)

Related Gene/Protein Pages

• [GPR37 Gene](/genes/gpr37)
• [PARKIN Protein](/proteins/parkin-protein)
• [Alpha-Synuclein Protein](/proteins/alpha-synuclein-protein)

References

Related Hypotheses

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

• [Bacterial Enzyme-Mediated Dopamine Precursor Synthesis](/hypothesis/h-7bb47d7a) — <span style="color:#ffd54f;font-weight:600">0.44</span> · Target: TH, AADC
• [Oligodendrocyte Protectin D1 Mimetic for Myelin Resolution](/hypothesis/h-f71a9791) — <span style="color:#ffd54f;font-weight:600">0.57</span> · Target: GPR37
• [Hippocampal CA3-CA1 circuit rescue via neurogenesis and synaptic preservation](/hypothesis/h-856feb98) — <span style="color:#81c784;font-weight:600">0.73</span> · Target: BDNF
• [Vagal Afferent Microbial Signal Modulation](/hypothesis/h-ee1df336) — <span style="color:#81c784;font-weight:600">0.71</span> · Target: GLP1R, BDNF
• [Oligodendrocyte Protectin D1 Mimetic for Myelin Resolution](/hypothesis/h-f71a9791) — <span style="color:#ffd54f;font-weight:600">0.57</span> · Target: GPR37
• [Vocal Cord Neuroplasticity Stimulation](/hypothesis/h-e0183502) — <span style="color:#ffd54f;font-weight:600">0.48</span> · Target: CHR2/BDNF
• [CYP46A1 Overexpression Gene Therapy](/hypothesis/h-2600483e) — <span style="color:#81c784;font-weight:600">0.79</span> · Target: CYP46A1
• [Gamma entrainment therapy to restore hippocampal-cortical synchrony](/hypothesis/h-bdbd2120) — <span style="color:#81c784;font-weight:600">0.77</span> · Target: SST

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• [Epigenetic clocks and biological aging in neurodegeneration](/analysis/SDA-2026-04-01-gap-v2-bc5f270e) &#x1f504;
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