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Harrison KR, Chervenak AP, Resnick SM, Reifler AN, Wong KY. Amacrine Cells Forming Gap Junctions With Intrinsically Photosensitive Retinal Ganglion Cells: ipRGC Types, Neuromodulator Contents, and Connexin Isoform. Invest Ophthalmol Vis Sci 2021; 62:10. [PMID: 33410914 PMCID: PMC7804497 DOI: 10.1167/iovs.62.1.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/30/2020] [Indexed: 12/11/2022] Open
Abstract
Purpose Intrinsically photosensitive retinal ganglion cells (ipRGCs) signal not only centrally to non-image-forming visual centers of the brain but also intraretinally to amacrine interneurons through gap junction electrical coupling, potentially modulating image-forming retinal processing. We aimed to determine (1) which ipRGC types couple with amacrine cells, (2) the neuromodulator contents of ipRGC-coupled amacrine cells, and (3) whether connexin36 (Cx36) contributes to ipRGC-amacrine coupling. Methods Gap junction-permeable Neurobiotin tracer was injected into green fluorescent protein (GFP)-labeled ipRGCs in Opn4Cre/+; Z/EG mice to stain coupled amacrine cells, and immunohistochemistry was performed to reveal the neuromodulator contents of the Neurobiotin-stained amacrine cells. We also created Opn4Cre/+; Cx36flox/flox; Z/EG mice to knock out Cx36 in GFP-labeled ipRGCs and looked for changes in the number of ipRGC-coupled amacrine cells. Results Seventy-three percent of ipRGCs, including all six types (M1-M6), were tracer-coupled with amacrine somas 5.7 to 16.5 µm in diameter but not with ganglion cells. Ninety-two percent of the ipRGC-coupled somas were in the ganglion cell layer and the rest in the inner nuclear layer. Some ipRGC-coupled amacrine cells were found to accumulate serotonin or to contain nitric oxide synthase or neuropeptide Y. Knocking out Cx36 in M2 and M4 dramatically reduced the number of coupled somas. Conclusions Heterologous gap junction coupling with amacrine cells is widespread across mouse ipRGC types. ipRGC-coupled amacrine cells probably comprise multiple morphologic types and use multiple neuromodulators, suggesting that gap junctional ipRGC-to-amacrine signaling likely exerts diverse modulatory effects on retinal physiology. ipRGC-amacrine coupling is mediated partly, but not solely, by Cx36.
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Affiliation(s)
- Krystal R. Harrison
- Department of Molecular, Cellular, & Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
| | - Andrew P. Chervenak
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Sarah M. Resnick
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Aaron N. Reifler
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
| | - Kwoon Y. Wong
- Department of Molecular, Cellular, & Developmental Biology, University of Michigan, Ann Arbor, Michigan, United States
- Department of Ophthalmology & Visual Sciences, University of Michigan, Ann Arbor, Michigan, United States
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2
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Ou K, Copland DA, Theodoropoulou S, Mertsch S, Li Y, Liu J, Schrader S, Liu L, Dick AD. Treatment of diabetic retinopathy through neuropeptide Y-mediated enhancement of neurovascular microenvironment. J Cell Mol Med 2020; 24:3958-3970. [PMID: 32141716 PMCID: PMC7171318 DOI: 10.1111/jcmm.15016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 12/02/2019] [Accepted: 12/27/2019] [Indexed: 12/12/2022] Open
Abstract
Diabetic retinopathy (DR) is one of the most severe clinical manifestations of diabetes mellitus and a major cause of blindness. DR is principally a microvascular disease, although the pathogenesis also involves metabolic reactive intermediates which induce neuronal and glial activation resulting in disruption of the neurovascular unit and regulation of the microvasculature. However, the impact of neural/glial activation in DR remains controversial, notwithstanding our understanding as to when neural/glial activation occurs in the course of disease. The objective of this study was to determine a potential protective role of neuropeptide Y (NPY) using an established model of DR permissive to N-methyl-D-aspartate (NMDA)-induced excitotoxic apoptosis of retinal ganglion cells (RGC) and vascular endothelial growth factor (VEGF)-induced vascular leakage. In vitro evaluation using primary retinal endothelial cells demonstrates that NPY promotes vascular integrity, demonstrated by maintained tight junction protein expression and reduced permeability in response to VEGF treatment. Furthermore, ex vivo assessment of retinal tissue explants shows that NPY can protect RGC from excitotoxic-induced apoptosis. In vivo clinical imaging and ex vivo tissue analysis in the diabetic model permitted assessment of NPY treatment in relation to neural and endothelial changes. The neuroprotective effects of NPY were confirmed by attenuating NMDA-induced retinal neural apoptosis and able to maintain inner retinal vascular integrity. These findings could have important clinical implications and offer novel therapeutic approaches for the treatment in the early stages of DR.
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Affiliation(s)
- Kepeng Ou
- College of Pharmacy, National and Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing, China.,Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - David A Copland
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Sofia Theodoropoulou
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Sonja Mertsch
- Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Department of Ophthalmology, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Youjian Li
- College of Pharmacy, National and Local Joint Engineering Research Center of Targeted and Innovative Therapeutics, Chongqing Key Laboratory of Kinase Modulators as Innovative Medicine, Chongqing University of Arts and Sciences, Chongqing, China.,Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Jian Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Stefan Schrader
- Laboratory for Experimental Ophthalmology, University of Düsseldorf, Düsseldorf, Germany.,Department of Ophthalmology, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - Lei Liu
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK
| | - Andrew D Dick
- Academic Unit of Ophthalmology, Bristol Medical School, University of Bristol, Bristol, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital, University College London Institute of Ophthalmology, London, UK
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3
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Reeber SL, Arancillo M, Sillitoe RV. Bergmann Glia are Patterned into Topographic Molecular Zones in the Developing and Adult Mouse Cerebellum. CEREBELLUM (LONDON, ENGLAND) 2018; 17:392-403. [PMID: 24906823 PMCID: PMC4291305 DOI: 10.1007/s12311-014-0571-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cerebellar circuits are patterned into an array of topographic parasagittal domains called zones. Zones are best revealed by gene expression, circuit anatomy, and cellular degeneration patterns. Thus far, the study of zones has been focused heavily on how neurons are organized. Because of this, detailed neuronal patterning maps have been established for Purkinje cells, granule cells, Golgi cells, unipolar brush cells, and also for the terminal field organization of climbing fiber and mossy fiber afferents. In comparison, however, it remains poorly understood if glial cells are also organized into zones. We have identified an Npy-Gfp BAC transgenic mouse line (Tau-Sapphire Green fluorescent protein (Gfp) is under the control of the neuropeptide Y (Npy) gene regulatory elements) that can be used to label Bergmann glial cells with Golgi-like resolution. In these adult transgenic mice, we found that Npy-Gfp expression was localized to Bergmann glia mainly in lobules VI/VII and IX/X. Using double immunofluorescence, we show that in these lobules, Npy-Gfp expression in the Bergmann glia overlaps with the pattern of the small heat shock protein HSP25, a Purkinje cell marker for zones located in lobules VI/VII and IX/X. Developmental analysis starting from the day of birth showed that HSP25 and Npy-Gfp expression follow a similar program of spatial and temporal patterning. However, loss of Npy signaling did not alter the patterning of Purkinje cell zones. We conclude that Bergmann glial cells are zonally organized and their patterns are restricted by boundaries that also confine cerebellar neurons into a topographic circuit map.
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Affiliation(s)
- Stacey L Reeber
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Marife Arancillo
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Department of Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, 1250 Moursund Street, Suite 1325, Houston, TX, 77030, USA.
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4
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Christiansen AT, Kiilgaard JF, Klemp K, Woldbye DPD, Hannibal J. Localization, distribution, and connectivity of neuropeptide Y in the human and porcine retinas-A comparative study. J Comp Neurol 2018; 526:1877-1895. [DOI: 10.1002/cne.24455] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 03/27/2018] [Accepted: 03/29/2018] [Indexed: 12/24/2022]
Affiliation(s)
| | - Jens Folke Kiilgaard
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - Kristian Klemp
- Department of Ophthalmology; Copenhagen University Hospital, Rigshospitalet; Denmark
| | - David Paul Drucker Woldbye
- Laboratory of Neural Plasticity; Center for Neuroscience, Faculty of Health Sciences, University of Copenhagen; Denmark
| | - Jens Hannibal
- Department of Clinical Biochemistry; Copenhagen University Hospital, Bispebjerg Hospital; Copenhagen Denmark
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5
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Allen RS, Sayeed I, Oumarbaeva Y, Morrison KC, Choi PH, Pardue MT, Stein DG. Progesterone treatment shows greater protection in brain vs. retina in a rat model of middle cerebral artery occlusion: Progesterone receptor levels may play an important role. Restor Neurol Neurosci 2018; 34:947-963. [PMID: 27802245 DOI: 10.3233/rnn-160672] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND/OBJECTIVE To determine whether inflammation increases in retina as it does in brain following middle cerebral artery occlusion (MCAO), and whether the neurosteroid progesterone, shown to have protective effects in both retina and brain after MCAO, reduces inflammation in retina as well as brain. METHODS MCAO rats treated systemically with progesterone or vehicle were compared with shams. Protein levels of cytosolic NF-κB, nuclear NF-κB, phosphorylated NF-κB, IL-6, TNF-α, CD11b, progesterone receptor A and B, and pregnane X receptor were assessed in retinas and brains at 24 and 48 h using western blots. RESULTS Following MCAO, significant increases were observed in the following inflammatory markers: pNF-κB and CD11b at 24 h in both brain and retina, nuclear NF-κB at 24 h in brain and 48 h in retina, and TNF-α at 24 h in brain.Progesterone treatment in MCAO animals significantly attenuated levels of the following markers in brain: pNF-κB, nuclear NF-κB, IL-6, TNF-α, and CD11b, with significantly increased levels of cytosolic NF-κB. Retinas from progesterone-treated animals showed significantly reduced levels of nuclear NF-κB and IL-6 and increased levels of cytosolic NF-κB, with a trend for reduction in other markers. Post-MCAO, progesterone receptors A and B were upregulated in brain and downregulated in retina. CONCLUSION Inflammatory markers increased in both brain and retina after MCAO, with greater increases observed in brain. Progesterone treatment reduced inflammation, with more dramatic reductions observed in brain than retina. This differential effect may be due to differences in the response of progesterone receptors in brain and retina after injury.
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Affiliation(s)
- Rachael S Allen
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA.,Department of Ophthalmology, Emory University, Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Iqbal Sayeed
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | - Yuliya Oumarbaeva
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | | | - Paul H Choi
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
| | - Machelle T Pardue
- Department of Ophthalmology, Emory University, Atlanta, GA, USA.,Center for Visual and Neurocognitive Rehabilitation, Atlanta VA Medical Center, Decatur, GA, USA
| | - Donald G Stein
- Department of Emergency Medicine, Emory University, Atlanta, GA, USA
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6
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Kaur H, Carvalho J, Looso M, Singh P, Chennupati R, Preussner J, Günther S, Albarrán-Juárez J, Tischner D, Classen S, Offermanns S, Wettschureck N. Single-cell profiling reveals heterogeneity and functional patterning of GPCR expression in the vascular system. Nat Commun 2017. [PMID: 28621310 PMCID: PMC5481776 DOI: 10.1038/ncomms15700] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
G-protein-coupled receptor (GPCR) expression is extensively studied in bulk cDNA, but heterogeneity and functional patterning of GPCR expression in individual vascular cells is poorly understood. Here, we perform a microfluidic-based single-cell GPCR expression analysis in primary smooth muscle cells (SMC) and endothelial cells (EC). GPCR expression is highly heterogeneous in all cell types, which is confirmed in reporter mice, on the protein level and in human cells. Inflammatory activation in murine models of sepsis or atherosclerosis results in characteristic changes in the GPCR repertoire, and we identify functionally relevant subgroups of cells that are characterized by specific GPCR patterns. We further show that dedifferentiating SMC upregulate GPCRs such as Gpr39, Gprc5b, Gprc5c or Gpr124, and that selective targeting of Gprc5b modulates their differentiation state. Taken together, single-cell profiling identifies receptors expressed on pathologically relevant subpopulations and provides a basis for the development of new therapeutic strategies in vascular diseases. GPCRs are key regulators of vascular functions. By analysing single-cell GPCRs expression in vascular smooth muscle and endothelial cells from healthy and diseased murine vessels, Kaur et al. show that GPCR expression is highly heterogeneous in all cell types and that disease causes GPCR repertoire changes depending on cell type and vascular localization.
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Affiliation(s)
- H Kaur
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - J Carvalho
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - M Looso
- ECCPS Bioinformatics Facility, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - P Singh
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - R Chennupati
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - J Preussner
- ECCPS Bioinformatics Facility, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - S Günther
- ECCPS Deep sequencing platform, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - J Albarrán-Juárez
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - D Tischner
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany
| | - S Classen
- Harvey Vascular Centre, Kerckhoff-Klinik, Benekestraße 2-8, 61231 Bad Nauheim, Germany
| | - S Offermanns
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany.,Medical Faculty, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - N Wettschureck
- Department of Pharmacology, Max Planck Institute for Heart and Lung Research, Ludwigstr 43, 61231 Bad Nauheim, Germany.,Medical Faculty, J.W. Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
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7
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Santos-Carvalho A, Ambrósio AF, Cavadas C. Neuropeptide Y system in the retina: From localization to function. Prog Retin Eye Res 2015; 47:19-37. [DOI: 10.1016/j.preteyeres.2015.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Revised: 03/05/2015] [Accepted: 03/10/2015] [Indexed: 01/10/2023]
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8
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Kayakabe M, Kakizaki T, Kaneko R, Sasaki A, Nakazato Y, Shibasaki K, Ishizaki Y, Saito H, Suzuki N, Furuya N, Yanagawa Y. Motor dysfunction in cerebellar Purkinje cell-specific vesicular GABA transporter knockout mice. Front Cell Neurosci 2014; 7:286. [PMID: 24474904 PMCID: PMC3893617 DOI: 10.3389/fncel.2013.00286] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 12/20/2013] [Indexed: 01/24/2023] Open
Abstract
γ-Aminobutyric acid (GABA) is a major inhibitory neurotransmitter in the adult mammalian central nervous system and plays modulatory roles in neural development. The vesicular GABA transporter (VGAT) is an essential molecule for GABAergic neurotransmission due to its role in vesicular GABA release. Cerebellar Purkinje cells (PCs) are GABAergic projection neurons that are indispensable for cerebellar function. To elucidate the significance of VGAT in cerebellar PCs, we generated and characterized PC-specific VGAT knockout (L7-VGAT) mice. VGAT mRNAs and proteins were specifically absent in the 40-week-old L7-VGAT PCs. The morphological characteristics, such as lamination and foliation of the cerebellar cortex, of the L7-VGAT mice were similar to those of the control littermate mice. Moreover, the protein expression levels and patterns of pre- (calbindin and parvalbumin) and postsynaptic (GABA-A receptor α1 subunit and gephyrin) molecules between the L7-VGAT and control mice were similar in the deep cerebellar nuclei that receive PC projections. However, the L7-VGAT mice performed poorly in the accelerating rotarod test and displayed ataxic gait in the footprint test. The L7-VGAT mice also exhibited severer ataxia as VGAT deficits progressed. These results suggest that VGAT in cerebellar PCs is not essential for the rough maintenance of cerebellar structure, but does play an important role in motor coordination. The L7-VGAT mice are a novel model of ataxia without PC degeneration, and would also be useful for studying the role of PCs in cognition and emotion.
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Affiliation(s)
- Mikiko Kayakabe
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Japan ; Japan Science and Technology Agency CREST, Tokyo, Japan ; Department of Otolaryngology-Head and Neck Surgery, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Toshikazu Kakizaki
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Japan ; Japan Science and Technology Agency CREST, Tokyo, Japan
| | - Ryosuke Kaneko
- Japan Science and Technology Agency CREST, Tokyo, Japan ; Institute of Experimental Animal Research, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Atsushi Sasaki
- Department of Pathology, Saitama Medical University Moroyama, Japan
| | - Yoichi Nakazato
- Department of Human Pathology, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Koji Shibasaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Yasuki Ishizaki
- Department of Molecular and Cellular Neurobiology, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Hiromitsu Saito
- Department of Animal Genomics, Functional Genomics Institute, Mie University Life Science Research Center Tsu, Japan
| | - Noboru Suzuki
- Department of Animal Genomics, Functional Genomics Institute, Mie University Life Science Research Center Tsu, Japan
| | - Nobuhiko Furuya
- Department of Otolaryngology-Head and Neck Surgery, Gunma University Graduate School of Medicine Maebashi, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine Maebashi, Japan ; Japan Science and Technology Agency CREST, Tokyo, Japan
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9
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Beck B, Pourié G. Ghrelin, neuropeptide Y, and other feeding-regulatory peptides active in the hippocampus: role in learning and memory. Nutr Rev 2013; 71:541-61. [PMID: 23865799 DOI: 10.1111/nure.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The hippocampus is a brain region of primary importance for neurogenesis, which occurs during early developmental states as well as during adulthood. Increases in neuronal proliferation and in neuronal death with age have been associated with drastic changes in memory and learning. Numerous neurotransmitters are involved in these processes, and some neuropeptides that mediate neurogenesis also modulate feeding behavior. Concomitantly, feeding peptides, which act primarily in the hypothalamus, are also present in the hippocampus. This review aims to ascertain the role of several important feeding peptides in cognitive functions, either through their local synthesis in the hippocampus or through their actions via specific receptors in the hippocampus. A link between neurogenesis and the orexigenic or anorexigenic properties of feeding peptides is discussed.
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Affiliation(s)
- Bernard Beck
- INSERM U954, Nutrition, Génétique et Expositions aux Risques Environnementaux, Faculté de Médecine, Vandœuvre, France.
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10
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Insel PA, Snead A, Murray F, Zhang L, Yokouchi H, Katakia T, Kwon O, Dimucci D, Wilderman A. GPCR expression in tissues and cells: are the optimal receptors being used as drug targets? Br J Pharmacol 2012; 165:1613-1616. [PMID: 21488863 DOI: 10.1111/j.1476-5381.2011.01434.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
G-protein-coupled receptors [GPCRs, also known as 7-transmembrane (7-TM) receptors] comprise the largest family of membrane receptors in humans and other species and, in addition, represent the greatest number of current drug targets. In this article, we review methods to define GPCR expression and data indicating that individual cells express >100 different GPCRs. Results from studies that have quantified expression of these receptors lead us to conclude that the optimal GPCRs may not be currently used as therapeutic targets. We propose that studies of GPCR expression in individual cells will likely reveal new insights regarding cellular physiology and therapeutic approaches. Findings that define and characterize the most highly expressed GPCRs thus have important potential in terms of identifying new drug targets and novel therapies directed at a wide range of clinical disorders.
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Affiliation(s)
- P A Insel
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - A Snead
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - F Murray
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - L Zhang
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - H Yokouchi
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - T Katakia
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - O Kwon
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - D Dimucci
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
| | - A Wilderman
- Departments of PharmacologyMedicine, University of California, San Diego, La Jolla, CA, USA
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11
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Dubois CJ, Ramamoorthy P, Whim MD, Liu SJ. Activation of NPY type 5 receptors induces a long-lasting increase in spontaneous GABA release from cerebellar inhibitory interneurons. J Neurophysiol 2011; 107:1655-65. [PMID: 22190627 DOI: 10.1152/jn.00755.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neuropeptide Y (NPY), a widely distributed neuropeptide in the central nervous system, can transiently suppress inhibitory synaptic transmission and alter membrane excitability via Y2 and Y1 receptors (Y2rs and Y1rs), respectively. Although many GABAergic neurons express Y5rs, the functional role of these receptors in inhibitory neurons is not known. Here, we investigated whether activation of Y5rs can modulate inhibitory transmission in cerebellar slices. Unexpectedly, application of NPY triggered a long-lasting increase in the frequency of miniature inhibitory postsynaptic currents in stellate cells. NPY also induced a sustained increase in spontaneous GABA release in cultured cerebellar neurons. When cerebellar cultures were examined for Y5r immunoreactivity, the staining colocalized with that of VGAT, a presynaptic marker for GABAergic cells, suggesting that Y5rs are located in the presynaptic terminals of inhibitory neurons. RT-PCR experiments confirmed the presence of Y5r mRNA in the cerebellum. The NPY-induced potentiation of GABA release was blocked by Y5r antagonists and mimicked by application of a selective peptide agonist for Y5r. Thus Y5r activation is necessary and sufficient to trigger an increase in GABA release. Finally, the potentiation of inhibitory transmission could not be reversed by a Y5r antagonist once it was initiated, consistent with the development of a long-term potentiation. These results indicate that activation of presynaptic Y5rs induces a sustained increase in spontaneous GABA release from inhibitory neurons in contrast to the transient suppression of inhibitory transmission that is characteristic of Y1r and Y2r activation. Our findings thus reveal a novel role of presynaptic Y5rs in inhibitory interneurons in regulating GABA release and suggest that these receptors could play a role in shaping neuronal network activity in the cerebellum.
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Affiliation(s)
- C J Dubois
- Department of Cell Biology and Anatomy, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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12
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Nakamura NH, Akiyama K, Naito T. Suppression of cAMP-dependent gene expression by cholecystokinin in the hippocampus. Neuroscience 2011; 187:15-23. [PMID: 21540082 DOI: 10.1016/j.neuroscience.2011.04.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 03/18/2011] [Accepted: 04/13/2011] [Indexed: 11/25/2022]
Abstract
Our previous study suggests that "the neuropeptidergic system" might promote a diversity of the mechanisms that regulate signal transmission in the hippocampus. Cholecystokinin (CCK) is the mostly expressed neuropeptide gene in the hippocampus. Here, we investigated whether CCK regulates immediate-early genes (Egr1/zif268 and Fos), critical indicators of cortical neuronal activity. We showed that CCK increased Egr1/zif268 promoter activity in a neuronal cell line, which is transfected with CCK(B) receptor. Unexpectedly, in living hippocampal slices, CCK significantly suppressed cAMP-induced expression of Egr1/zif268 and Fos through CCK(B) receptor activation. This suppression was involved in activating GABA(B) and cannabinoid 1 receptors. In addition to transient CCK modulation of action potentials on hippocampal principal neurons, we suggest that release of endogenous CCK might indirectly produce the suppression of cAMP-dependent gene expression in the hippocampus.
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Affiliation(s)
- N H Nakamura
- Okinawa Institute of Science and Technology, Okinawa 904-2234, Japan.
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13
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Nakamura NH, Akiyama K, Naito T. Quantitative gene-expression analysis of the ligand-receptor system for classical neurotransmitters and neuropeptides in hippocampal CA1, CA3, and dentate gyrus. Hippocampus 2010; 21:1228-39. [PMID: 20623762 DOI: 10.1002/hipo.20830] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2010] [Indexed: 11/08/2022]
Abstract
We have shown quantitative expression levels of genes coding for the "ligand-receptor system" for classical neurotransmitters and neuropeptides in hippocampal subregions CA1, CA3, and dentate gyrus (DG). Using a combination of DNA microarray and quantitative PCR methods, we found that the three subregions have relatively similar expression patterns of ionotropic receptors for classical neurotransmitters. Expression of ionotropic receptors for glutamate and GABA represents more than 90% of all ionotropic receptors for classical neurotransmitters, and the expression ratio between ionotropic receptors for glutamate and GABA is constant (1.2:1-1.6:1) in each subregion. Meanwhile, the three subregions have different expression patterns of neuropeptide receptors. Furthermore, there are asymmetric expression patterns between neuropeptides and their receptors. Expression of Cck, Npy, Sst, and Penk1 represents 90% of neuropeptides derived locally in the hippocampus, whereas expression of these four neuropeptide receptors accounts for 50% of G protein-coupled receptors for neuropeptides. We propose that CA1, CA3, and DG have different modalities based on the ligand-receptor system, particularly the "neuropeptidergic system." Our quantitative gene-expression analysis provides fundamental data to support functional differences between the three hippocampal subregions regarding ligand-receptor interactions.
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Affiliation(s)
- Nozomu H Nakamura
- Molecular Neuroscience Unit, Okinawa Institute of Science and Technology, Japan.
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Ito M. Functional roles of neuropeptides in cerebellar circuits. Neuroscience 2009; 162:666-72. [PMID: 19361475 DOI: 10.1016/j.neuroscience.2009.01.019] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 01/09/2009] [Indexed: 11/16/2022]
Abstract
Whereas the cerebellum contains 22 different types of neuropeptides as presently known, their expression is generally weak and diffusely dispersed in cerebellar tissues, which often makes their functional significance doubtful. Nevertheless, our knowledge about certain neuropeptides has advanced to the extent that we can figure out their unique functional roles in cerebellar circuits. Throughout the cerebellum, CRF is contained in climbing fibers and its spontaneous release is required for the induction of cerebellar long-term depression (LTD), a cellular mechanism of motor learning. Corticotropin-releasing factor (CRF) is also expressed in the paraventricular nucleus-pituitary system and amygdala-lower brainstem system, both of which are involved in coping responses to stress. In view that motor learning requires stressful efforts for correcting errors in repeated trials, CRF in climbing fibers may imply that the olivocerebellar system is part of a large CRF-operated functional system that acts to cope with various stressors. Orexin, on the other hand, is contained in beaded fibers, which, originating from the hypothalamus, project to various brainstem nuclei and also to the cerebellum, exclusively the flocculus. Currently available evidence suggests that, in fight-or-flight situations, orexinergic neurons switch the state of cardiovascular control systems including the flocculus to secure blood supply to working muscles. Considerable knowledge has also been accumulated about angiotensin II, galanin, and cerebellin, but there is still a gap in defining their unique functional roles in cerebellar circuits.
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Affiliation(s)
- M Ito
- RIKEN, Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
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