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Bolinger AA, Frazier A, La JH, Allen JA, Zhou J. Orphan G Protein-Coupled Receptor GPR37 as an Emerging Therapeutic Target. ACS Chem Neurosci 2023; 14:3318-3334. [PMID: 37676000 PMCID: PMC11144446 DOI: 10.1021/acschemneuro.3c00479] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/08/2023] Open
Abstract
G protein-coupled receptors (GPCRs) are successful druggable targets, making up around 35% of all FDA-approved medications. However, a large number of receptors remain orphaned, with no known endogenous ligand, representing a challenging but untapped area to discover new therapeutic targets. Among orphan GPCRs (oGPCRs) of interest, G protein-coupled receptor 37 (GPR37) is highly expressed in the central nervous system (CNS), particularly in the spinal cord and oligodendrocytes. While its cellular signaling mechanisms and endogenous receptor ligands remain elusive, GPR37 has been implicated in several important neurological conditions, including Parkinson's disease (PD), inflammation, pain, autism, and brain tumors. GPR37 structure, signaling, emerging physiology, and pharmacology are reviewed while integrating a discussion on potential therapeutic indications and opportunities.
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Affiliation(s)
- Andrew A. Bolinger
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Andrew Frazier
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jun-Ho La
- Department of Neurobiology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - John A. Allen
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, Center for Addiction Sciences and Therapeutics, University of Texas Medical Branch, Galveston, Texas 77555, United States
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2
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Massimi M, Di Pietro C, La Sala G, Matteoni R. Mouse Mutants of Gpr37 and Gpr37l1 Receptor Genes: Disease Modeling Applications. Int J Mol Sci 2022; 23:ijms23084288. [PMID: 35457105 PMCID: PMC9025225 DOI: 10.3390/ijms23084288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 02/05/2023] Open
Abstract
The vertebrate G protein–coupled receptor 37 and G protein–coupled receptor 37-like 1 (GPR37 and GPR37L1) proteins have amino acid sequence homology to endothelin and bombesin-specific receptors. The prosaposin glycoprotein, its derived peptides, and analogues have been reported to interact with and activate both putative receptors. The GPR37 and GPR37L1 genes are highly expressed in human and rodent brains. GPR37 transcripts are most abundant in oligodendrocytes and in the neurons of the substantia nigra and hippocampus, while the GPR37L1 gene is markedly expressed in cerebellar Bergmann glia astrocytes. The human GPR37 protein is a substrate of parkin, and its insoluble form accumulates in brain samples from patients of inherited juvenile Parkinson’s disease. Several Gpr37 and Gpr37l1 mouse mutant strains have been produced and applied to extensive in vivo and ex vivo analyses of respective receptor functions and involvement in brain and other organ pathologies. The genotypic and phenotypic characteristics of the different mouse strains so far published are reported and discussed, and their current and proposed applications to human disease modeling are highlighted.
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3
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Taniguchi M, Nabeka H, Yamamiya K, Khan MSI, Shimokawa T, Islam F, Doihara T, Wakisaka H, Kobayashi N, Hamada F, Matsuda S. The expression of prosaposin and its receptors, GRP37 and GPR37L1, are increased in the developing dorsal root ganglion. PLoS One 2021; 16:e0255958. [PMID: 34379697 PMCID: PMC8357083 DOI: 10.1371/journal.pone.0255958] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 07/27/2021] [Indexed: 11/18/2022] Open
Abstract
Prosaposin (PSAP), a highly conserved glycoprotein, is a precursor of saposins A-D. Accumulating evidence suggests that PSAP is a neurotrophic factor, as well as a regulator of lysosomal enzymes. Recently, the orphan G-protein-coupled receptors GPR37 and GPR37L1 were recognized as PSAP receptors, but their functions have not yet been clarified. In this study, we examined the distribution of PSAP and its receptors in the dorsal root ganglion (DRG) during development using specific antibodies, and showed that PSAP accumulates primarily in lysosomes and is dispersed throughout the cytoplasm of satellite cells. Later, PSAP colocalized with two receptors in satellite cells, and formed a characteristic ring shape approximately 8 weeks after birth, during a period of rapid DRG development. This ring shape, which was only observed around larger neurons, is evidence that several satellite cells are synchronously activated. We found that sortilin, a transporter of a wide variety of intracellular proteins containing PSAP, is strongly localized to the inner side of satellite cells, which contact the neuronal surface. These findings suggest that PSAP and GPR37/GPR37L1 play a role in activating both satellite and nerve cells.
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Affiliation(s)
- Miho Taniguchi
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Hiroaki Nabeka
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Kimiko Yamamiya
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Md Sakirul Islam Khan
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Tetsuya Shimokawa
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Farzana Islam
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Takuya Doihara
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Hiroyuki Wakisaka
- Department of Otorhinolaryngology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Naoto Kobayashi
- Department of Medical Education Center, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Fumihiko Hamada
- Department of Human Anatomy, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Seiji Matsuda
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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4
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Kunihiro J, Nabeka H, Wakisaka H, Unuma K, Khan MSI, Shimokawa T, Islam F, Doihara T, Yamamiya K, Saito S, Hamada F, Matsuda S. Prosaposin and its receptors GRP37 and GPR37L1 show increased immunoreactivity in the facial nucleus following facial nerve transection. PLoS One 2020; 15:e0241315. [PMID: 33259479 PMCID: PMC7707515 DOI: 10.1371/journal.pone.0241315] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 10/13/2020] [Indexed: 12/21/2022] Open
Abstract
Neurotrophic factor prosaposin (PS) is a precursor for saposins A, B, C, and D, which are activators for specific sphingolipid hydrolases in lysosomes. Both saposins and PS are widely contained in various tissues. The brain, skeletal muscle, and heart cells predominantly contain unprocessed PS rather than saposins. PS and PS-derived peptides stimulate neuritogenesis and increase choline acetyltransferase activity in neuroblastoma cells and prevent programmed cell death in neurons. We previously detected increases in PS immunoactivity and its mRNA in the rat facial nucleus following facial nerve transection. PS mRNA expression increased not only in facial motoneurons, but also in microglia during facial nerve regeneration. In the present study, we examined the changes in immunoreactivity of the PS receptors GPR37 and GPR37L1 in the rat facial nucleus following facial nerve transection. Following facial nerve transection, many small Iba1- and glial fibrillary acidic protein (GFAP)-positive cells with strong GPR37L1 immunoreactivity, including microglia and astrocytes, were observed predominately on the operated side. These results indicate that GPR37 mainly works in neurons, whereas GPR37L1 is predominant in microglia or astrocytes, and suggest that increased PS in damaged neurons stimulates microglia or astrocytes via PS receptor GPR37L1 to produce neurotrophic factors for neuronal recovery.
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Affiliation(s)
- Joji Kunihiro
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Hiroaki Nabeka
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
- * E-mail:
| | - Hiroyuki Wakisaka
- Department of Otorhinolaryngology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Kana Unuma
- Section of Forensic Medicine, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Bunkyo, Tokyo, Japan
| | - Md. Sakirul Islam Khan
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Tetsuya Shimokawa
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Farzana Islam
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Takuya Doihara
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Kimiko Yamamiya
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Shouichiro Saito
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Yanagido, Gifu, Japan
| | - Fumihiko Hamada
- Department of Human Anatomy, Oita University Faculty of Medicine, Yufu, Oita, Japan
| | - Seiji Matsuda
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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5
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Dutta P, Dargahi L, O'Connell KE, Bolia A, Ozkan B, Sailer AW, Dev KK. A novel modelling mechanism of PAEL receptor and GABARAPL2 interaction involved in Parkinson's disease. Neurosci Lett 2018; 673:12-18. [PMID: 29496607 DOI: 10.1016/j.neulet.2018.02.055] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 01/30/2018] [Accepted: 02/25/2018] [Indexed: 11/18/2022]
Abstract
Parkin associated endothelin like receptor (PAELR) is G-protein coupled and ubiquitinated by parkin, promoting its degradation. In autosomal recessive Parkinson's disease, mutations in parkin lead to PAELR aggregation in the endoplasmic reticulum (ER), ER stress, neurotoxicity and cell death. We have identified previously that the protein kinase C interacting protein (PICK1) interacts with and regulates the expression and cell toxicity of PAELR. Here, we experimentally identify and provide in-silico modelling of a novel interaction between PAELR and GABARAPL2 (γ-aminobutyrate type A receptor associated protein like 2), which is an autophagosome-specific Ub-like protein implicated in vesicle trafficking and autophagy. We show that the family of GABARAPs interact with the carboxy terminal (ct) of PAELR and find the cysteine rich region (-CCCCCC-EEC) of ct-PAELR interacts with the GABAA binding site of GABARAPL2. This interaction is modelled by in-slico analysis and confirmed using affinity chromatography, showing Myc-tagged GABARAPL2 is retained by a GST fusion of the ct-PAELR. We also demonstrate that transient transfection of GABARAPL2 in HEK293 cells reduces PAELR expression. This study supports the idea that protein levels of PAELR are likely regulated by a multitude of proteins including parkin, PICK1 and GABARAPL2 via mechanisms that include ubiquitination, proteasomal degradagtion and autophagy.
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Affiliation(s)
- Priyanka Dutta
- Drug Development, School of Medicine, Trinity College Dublin, Ireland
| | - Leila Dargahi
- Drug Development, School of Medicine, Trinity College Dublin, Ireland
| | - Kara E O'Connell
- Drug Development, School of Medicine, Trinity College Dublin, Ireland
| | - Ashini Bolia
- Department of Physics, Center for Biological Physics, Arizona State University, Tempe, AZ, USA
| | - Banu Ozkan
- Department of Physics, Center for Biological Physics, Arizona State University, Tempe, AZ, USA
| | - Andreas W Sailer
- Developmental and Molecular Pathways, Novartis Institutes for BioMedical Research, Basel, Switzerland
| | - Kumlesh K Dev
- Drug Development, School of Medicine, Trinity College Dublin, Ireland.
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6
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Leinartaité L, Svenningsson P. Folding Underlies Bidirectional Role of GPR37/Pael-R in Parkinson Disease. Trends Pharmacol Sci 2017. [PMID: 28629580 DOI: 10.1016/j.tips.2017.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Since conformational flexibility, which is required for the function of a protein, comes at the expense of structural stability, many proteins, including G-protein-coupled receptors (GPCRs), are under constant risk of misfolding and aggregation. In this regard GPR37 (also named PAEL-R and ETBR-LP-1) takes a prominent role, particularly in relation to Parkinson disease (PD). GPR37 is a substrate for parkin and accumulates abnormally in autosomal recessive juvenile parkinsonism, contributing to endoplasmic reticulum stress and death of dopaminergic neurons. GPR37 also constitutes a core structure of Lewy bodies, demonstrating a more general involvement in PD pathology. However, if folded and matured properly, GPR37 seems to be neuroprotective. Moreover, GPR37 modulates functionality of the dopamine transporter and the dopamine D2 receptor and stimulates dopamine neurotransmission. Here we review the multiple roles of GPR37 with relevance to potential disease modification and symptomatic therapies of PD and highlight unsolved issues in this field.
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Affiliation(s)
- Lina Leinartaité
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, SE-171 76, Stockholm, Sweden.
| | - Per Svenningsson
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, SE-171 76, Stockholm, Sweden.
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Li X, Nabeka H, Saito S, Shimokawa T, Khan MSI, Yamamiya K, Shan F, Gao H, Li C, Matsuda S. Expression of prosaposin and its receptors in the rat cerebellum after kainic acid injection. IBRO Rep 2017; 2:31-40. [PMID: 30135931 PMCID: PMC6084904 DOI: 10.1016/j.ibror.2017.02.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 02/02/2017] [Accepted: 02/21/2017] [Indexed: 11/16/2022] Open
Abstract
Prosaposin (PSAP), a highly conserved glycoprotein, is a precursor of saposins A–D. Accumulating evidence suggests that PSAP is a neurotrophic factor that induces differentiation and prevents death in a variety of neuronal cells through the active region within the saposin C domain both in vivo and in vitro. Recently, GPR37 and GPR37L1 were recognized as PSAP receptors. In this study, we examined the alteration in expression of PSAP and its receptors in the cerebellum using rats injected with kainic acid (KA). The results show that PSAP was strongly expressed in the cytoplasm of Purkinje cells and interneurons in the molecular layer, and that PSAP expression in both types of neurons was markedly enhanced following KA treatment. Immunoblotting revealed that the expression of GPR37 was diminished significantly three days after KA injection compared with control rats; however, no changes were observed through immunostaining. No discernable changes were found in GPR37L1. These findings may help us to understand the role of PSAP and the GPR37 and GPR37L1 receptors in alleviating the neural damage caused by KA.
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Key Words
- BSA, bovine serum albumin
- Cerebellum
- ER, endoplasmic reticulum
- GPCR, G protein-coupled receptor
- GPR37
- GPR37L1
- H-E staining, hematoxylin-eosin staining
- IF, immunofluorescence
- IHC, immunohistochemistry
- ISH, in situ hybridization
- KA, kainic acid
- Kainic acid
- Neurodegeneration
- PSAP, prosaposin
- Prosaposin
- SSC, standard saline citrate
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Affiliation(s)
- Xuan Li
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Hiroaki Nabeka
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Shouichiro Saito
- Laboratory of Veterinary Anatomy, Faculty of Applied Biological Sciences, Gifu University, Yanagido, Gifu, Japan
| | - Tetsuya Shimokawa
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Md Sakirul Islam Khan
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Kimiko Yamamiya
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| | - Fengping Shan
- Department of Immunology, School of Basic Medical Science, China Medical University, Shenyang, PR China
| | - Huiling Gao
- College of Life and Health Science, Northeastern University, Shenyang, PR China
| | - Cheng Li
- Department of Immunology, School of Basic Medical Science, China Medical University, Shenyang, PR China
| | - Seiji Matsuda
- Department of Anatomy and Embryology, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
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8
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Xie J, Wu X, Zhou Q, Yang Y, Tian Y, Huang C, Meng X, Li J. PICK1 confers anti-inflammatory effects in acute liver injury via suppressing M1 macrophage polarization. Biochimie 2016; 127:121-32. [PMID: 27157267 DOI: 10.1016/j.biochi.2016.05.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
Protein interacting with C kinase 1 (PICK1) is a scaffolding protein mainly implicated in neurological diseases, however, the function of PICK1 in acute liver injury (ALI) remains unknown. Our study found a dramatical decrease in mRNA and protein levels of PICK1 in liver tissues and isolated Kupffer cells (KCs) from the liver in mice with ALI. Furthermore, pretreatment the mice with ALI with FSC-231, a pharmacological inhibitor of PICK1, could significantly augment inflammatory response. Furthermore, in vitro studies showed that both lipopolysaccharide (LPS) and interferon gamma (IFN-γ) significantly reduced the expression of PICK1, while IL-4 elevated its expression in RAW 264.7 cells. Additionally, over-expression of PICK1 inhibited the expression of M1 biomarkers by suppressing NF-κB activity, and enhanced the expression of M2 biomarkers by promoting STAT6 activity. In contrast, knockdown of PICK1 or FSC-231 pretreatment promoted M1 polarization and suppressed M2 polarization. Besides, caveolin-1 was identified as a potential target gene controlled by PICK1 in RAW 264.7 cells. Mechanistic investigation revealed a dual role of PICK1 in regulating macrophage polarization and implied PICK1 as a potential therapeutic target in ALI.
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Affiliation(s)
- Juan Xie
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Xiaoqin Wu
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Qun Zhou
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Yang Yang
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Yuanyao Tian
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Cheng Huang
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Xiaoming Meng
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Meishan Road, Hefei, 230032, China; Institute for Liver Diseases of Anhui Medical University (AMU), China; Anhui Key Laboratory of Bioactivity of Natural Products, Anhui Medical University, Hefei, 230032, China.
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9
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Mattila SO, Tuusa JT, Petäjä-Repo UE. The Parkinson's-disease-associated receptor GPR37 undergoes metalloproteinase-mediated N-terminal cleavage and ectodomain shedding. J Cell Sci 2016; 129:1366-77. [PMID: 26869225 DOI: 10.1242/jcs.176115] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/08/2016] [Indexed: 12/20/2022] Open
Abstract
The G-protein-coupled receptor 37 ( GPR37) has been implicated in the juvenile form of Parkinson's disease, in dopamine signalling and in the survival of dopaminergic cells in animal models. The structure and function of the receptor, however, have remained enigmatic. Here, we demonstrate that although GPR37 matures and is exported from the endoplasmic reticulum in a normal manner upon heterologous expression in HEK293 and SH-SY5Y cells, its long extracellular N-terminus is subject to metalloproteinase-mediated limited proteolysis between E167 and Q168. The proteolytic processing is a rapid and efficient process that occurs constitutively. Moreover, the GPR37 ectodomain is released from cells by shedding, a phenomenon rarely described for GPCRs. Immunofluorescence microscopy further established that although full-length receptors are present in the secretory pathway until the trans-Golgi network, GPR37 is expressed at the cell surface predominantly in the N-terminally truncated form. This notion was verified by flow cytometry and cell surface biotinylation assays. These new findings on the GPR37 N-terminal limited proteolysis may help us to understand the role of this GPCR in the pathophysiology of Parkinson's disease and in neuronal function in general.
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Affiliation(s)
- S Orvokki Mattila
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
| | - Jussi T Tuusa
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
| | - Ulla E Petäjä-Repo
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
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10
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Smith NJ. Drug Discovery Opportunities at the Endothelin B Receptor-Related Orphan G Protein-Coupled Receptors, GPR37 and GPR37L1. Front Pharmacol 2015; 6:275. [PMID: 26635605 PMCID: PMC4648071 DOI: 10.3389/fphar.2015.00275] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/30/2015] [Indexed: 01/01/2023] Open
Abstract
Orphan G protein-coupled receptors (GPCRs) represent a largely untapped resource for the treatment of a variety of diseases, despite sophisticated advances in drug discovery. Two promising orphan GPCRs are the endothelin B receptor-like proteins, GPR37 [ET(B)R-LP, Pael-R] and GPR37L1 [ET(B)R-LP-2]. Originally identified through searches for homologs of endothelin and bombesin receptors, neither GPR37 nor GPR37L1 were found to bind endothelins or related peptides. Instead, GPR37 was proposed to be activated by head activator (HA) and both GPR37 and GPR37L1 have been linked to the neuropeptides prosaposin and prosaptide, although these pairings are yet to be universally acknowledged. Both orphan GPCRs are widely expressed in the brain, where GPR37 has received the most attention for its link to Parkinson’s disease and parkinsonism, while GPR37L1 deletion leads to precocious cerebellar development and hypertension. In this review, the existing pharmacology and physiology of GPR37 and GPR37L1 is discussed and the potential therapeutic benefits of targeting these receptors are explored.
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Affiliation(s)
- Nicola J Smith
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute , Darlinghurst, NSW, Australia ; St. Vincent's Clinical School, University of New South Wales , Darlinghurst, NSW, Australia
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11
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Tanabe Y, Fujita-Jimbo E, Momoi MY, Momoi T. CASPR2 forms a complex with GPR37 via MUPP1 but not with GPR37(R558Q), an autism spectrum disorder-related mutation. J Neurochem 2015; 134:783-93. [DOI: 10.1111/jnc.13168] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Revised: 04/25/2015] [Accepted: 05/06/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Yuko Tanabe
- International University of Health and Welfare; Otawara Tochigi Japan
| | - Eriko Fujita-Jimbo
- International University of Health and Welfare; Otawara Tochigi Japan
- Department of Pediatrics; Jichi Medical University School of Medicine; Shimotsuke Tochigi Japan
| | - Mariko Y. Momoi
- International University of Health and Welfare; Otawara Tochigi Japan
| | - Takashi Momoi
- International University of Health and Welfare; Otawara Tochigi Japan
- Department of Pathophysiology; Tokyo Medical University Shinjuku Tokyo, Japan
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