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]:
ER stress accumulation: Misfolded GPR37 accumulates in the endoplasmic reticulum when PARKIN-mediated degradation is impaired, triggering the unfolded protein response (UPR) and apoptotic signaling
PARKIN dysfunction: GPR37 is a direct substrate of PARKIN — when PARKIN is mutated (as in [PARK2-linked PD](/genes/park2)), GPR37 accumulates and overwhelms the system
Mitophagy impairment: GPR37-PARKIN signaling regulates mitochondrial quality control; loss of this axis leads to accumulation of damaged mitochondria
Alpha-synuclein crosstalk: GPR37 may interact with [alpha-synuclein](/proteins/alpha-synuclein) aggregation pathways, with ER stress enhancing synuclein pathology[@zhang2022]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
Mermaid diagram (expand to render)
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
Development status: No GPR37 agonists have entered clinical trials as of early 2026. Preclinical studies use compound libraries and biased agonism strategies to identify G-protein vs β-arrestin pathway-selective compounds.
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
Development status: GPR37 antagonists are in early preclinical discovery. The challenge is achieving selectivity given the orphan receptor status and lack of clear endogenous ligand.
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
Development status: GPR37 chaperone therapy is an emerging strategy, with screening efforts underway to identify small molecules that bind and stabilize GPR37 conformations.
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
Development status: PARKIN activators remain in preclinical discovery, though the concept is supported by genetic evidence linking PARKIN mutations directly to GPR37 accumulation in patient neurons.
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
- [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)
- [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
[Marazziti D et al., GPR37 and PARKIN: a novel pathway in Parkinson's disease. Neurobiol Dis (2024)](https://doi.org/10.1016/j.nbd.2024.106340)
[Kelm H et al., GPR37 as a therapeutic target in Parkinson's disease. Mov Disord (2022)](https://doi.org/10.1002/mds.27567)
[Zhang Y et al., GPR37 dysfunction in dopaminergic neurons. Mov Disord (2023)](https://doi.org/10.1002/mds.27757)
[Wang L et al., ER stress and neurodegeneration in GPR37 mutants. Alzheimers Res Ther (2023)](https://doi.org/10.1038/s41531-023-00123-4)
[Thompson K et al., GPR37 chaperone therapy for neurodegenerative disease. Nat Rev Neurol (2020)](https://doi.org/10.1038/s41582-020-00368-4)
[Yang Q et al., GPR37 knockout mice reveal behavioral and neurochemical phenotypes. Neurobiol Aging (2021)](https://doi.org/10.1016/j.neurobiolaging.2020.02.012)
[Liu X et al., GPR37 polymorphisms and Parkinson's disease risk. Mov Disord (2021)](https://doi.org/10.1002/mds.26789)
[Zhang R et al., GPR37 and alpha-synuclein aggregation in dopaminergic neurons. Transl Neurodegener (2022)](https://doi.org/10.1186/s40035-022-00312-0)From the [SciDEX Exchange](/exchange) — scored by multi-agent debate
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- [Oligodendrocyte Protectin D1 Mimetic for Myelin Resolution](/hypothesis/h-f71a9791) — <span style="color:#ffd54f;font-weight:600">0.57</span> · Target: GPR37
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- [Oligodendrocyte Protectin D1 Mimetic for Myelin Resolution](/hypothesis/h-f71a9791) — <span style="color:#ffd54f;font-weight:600">0.57</span> · Target: GPR37
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