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Hurst K, Badgley C, Ellsworth T, Bell S, Friend L, Prince B, Welch J, Cowan Z, Williamson R, Lyon C, Anderson B, Poole B, Christensen M, McNeil M, Call J, Edwards JG. A putative lysophosphatidylinositol receptor GPR55 modulates hippocampal synaptic plasticity. Hippocampus 2017; 27:985-998. [PMID: 28653801 DOI: 10.1002/hipo.22747] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/22/2017] [Accepted: 05/26/2017] [Indexed: 11/08/2022]
Abstract
GPR55, an orphan G-protein coupled receptor, is activated by lysophosphatidylinositol (LPI) and the endocannabinoid anandamide, as well as by other compounds including THC. LPI is a potent endogenous ligand of GPR55 and neither GPR55 nor LPIs' functions in the brain are well understood. While endocannabinoids are well known to modulate brain synaptic plasticity, the potential role LPI could have on brain plasticity has never been demonstrated. Therefore, we examined not only GPR55 expression, but also the role its endogenous ligand could play in long-term potentiation, a common form of synaptic plasticity. Using quantitative RT-PCR, electrophysiology, and behavioral assays, we examined hippocampal GPR55 expression and function. qRT-PCR results indicate that GPR55 is expressed in hippocampi of both rats and mice. Immunohistochemistry and single cell PCR demonstrates GPR55 protein in pyramidal cells of CA1 and CA3 layers in the hippocampus. Application of the GPR55 endogenous agonist LPI to hippocampal slices of GPR55+/+ mice significantly enhanced CA1 LTP. This effect was absent in GPR55-/- mice, and blocked by the GPR55 antagonist CID 16020046. We also examined paired-pulse ratios of GPR55-/- and GPR55+/+ mice with or without LPI and noted significant enhancement in paired-pulse ratios by LPI in GPR55+/+ mice. Behaviorally, GPR55-/- and GPR55+/+ mice did not differ in memory tasks including novel object recognition, radial arm maze, or Morris water maze. However, performance on radial arm maze and elevated plus maze task suggests GPR55-/- mice have a higher frequency of immobile behavior. This is the first demonstration of LPI involvement in hippocampal synaptic plasticity.
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Affiliation(s)
- Katrina Hurst
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Corinne Badgley
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Tanner Ellsworth
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Spencer Bell
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
| | - Lindsey Friend
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
| | - Brad Prince
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Jacob Welch
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Zack Cowan
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Ryan Williamson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
| | - Chris Lyon
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Brandon Anderson
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Brian Poole
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
| | - Michael Christensen
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
| | - Michael McNeil
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Jarrod Call
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602
| | - Jeffrey G Edwards
- Department of Physiology and Developmental Biology, Brigham Young University, Provo, Utah, 84602.,Neuroscience Center, Brigham Young University, Provo, Utah, 84602
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Role of GPR55 during Axon Growth and Target Innervation. eNeuro 2015; 2:eN-NWR-0011-15. [PMID: 26730399 PMCID: PMC4699829 DOI: 10.1523/eneuro.0011-15.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 09/24/2015] [Accepted: 10/15/2015] [Indexed: 12/26/2022] Open
Abstract
Guidance molecules regulate the navigation of retinal ganglion cell (RGC) projections toward targets in the visual thalamus. In this study, we demonstrate that the G-protein-coupled receptor 55 (GPR55) is expressed in the retina during development, and regulates growth cone (GC) morphology and axon growth. In vitro, neurons obtained from gpr55 knock-out (gpr55-/-) mouse embryos have smaller GCs, less GC filopodia, and have a decreased outgrowth compared with gpr55+/+ neurons. When gpr55+/+ neurons were treated with GPR55 agonists, lysophosphatidylinositol (LPI) and O-1602, we observed a chemo-attractive effect and an increase in GC size and filopodia number. In contrast, cannabidiol (CBD) decreased the GC size and filopodia number inducing chemo-repulsion. In absence of the receptor (gpr55-/-), no pharmacologic effects of the GPR55 ligands were observed. In vivo, compared to their wild-type (WT) littermates, gpr55-/- mice revealed a decreased branching in the dorsal terminal nucleus (DTN) and a lower level of eye-specific segregation of retinal projections in the superior colliculus (SC) and in the dorsal lateral geniculate nucleus (dLGN). Moreover, a single intraocular injection of LPI increased branching in the DTN, whereas treatment with CBD, an antagonist of GPR55, decreased it. These results indicate that GPR55 modulates the growth rate and the targets innervation of retinal projections and highlight, for the first time, an important role of GPR55 in axon refinement during development.
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Kallendrusch S, Kremzow S, Nowicki M, Grabiec U, Winkelmann R, Benz A, Kraft R, Bechmann I, Dehghani F, Koch M. The G Protein-Coupled Receptor 55 Ligandl-α-Lysophosphatidylinositol Exerts Microglia-Dependent Neuroprotection After Excitotoxic Lesion. Glia 2013; 61:1822-31. [DOI: 10.1002/glia.22560] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 07/15/2013] [Accepted: 07/16/2013] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | | | - Ria Winkelmann
- Senckenbergisches Institut für Pathologie, Goethe Universität Frankfurt am Main; Germany
| | - Alexander Benz
- Senckenbergisches Institut für Pathologie, Goethe Universität Frankfurt am Main; Germany
| | - Robert Kraft
- Carl-Ludwig Institut für Physiologie, Universität Leipzig; Germany
| | | | | | - Marco Koch
- Institut für Anatomie, Universität Leipzig; Germany
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