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Wang M, Li Z, Song Y, Sun Q, Deng L, Lin Z, Zeng Y, Qiu C, Lin J, Guo H, Chen J, Guo W. Genetic tagging of the adenosine A2A receptor reveals its heterogeneous expression in brain regions. Front Neuroanat 2022; 16:978641. [PMID: 36059431 PMCID: PMC9434489 DOI: 10.3389/fnana.2022.978641] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2022] [Accepted: 07/29/2022] [Indexed: 11/22/2022] Open
Abstract
The adenosine A2A receptor (A2AR), a G protein-coupled receptor, is involved in numerous and varied physiological and pathological processes, including inflammation, immune responses, blood flow, and neurotransmission. Accordingly, it has become an important drug target for the treatment of neuropsychiatric disorders. However, the exact brain distribution of A2AR in regions outside the striatum that display relatively low levels of endogenous A2AR expression has hampered the exploration of A2AR functions under both physiological and pathological conditions. To further study the detailed distribution of the A2AR in low-expression regions, we have generated A2AR knock-in mice in which the 3xHA-2xMyc epitope tag sequence was fused to the C-terminus of A2AR (A2AR-tag mice) via CRISPR/Cas9 technology. Here, using CRISPR/Cas9 technology, we have generated A2AR knock-in mice in which the 3xHA-2xMyc epitope tag sequence was fused to the C-terminus of A2AR (A2AR-tag mice). The A2AR-tag mice exhibited normal locomotor activity and emotional state. Consistent with previous studies, A2AR fluorescence was widely detected in the striatum, nucleus accumbens, and olfactory tubercles, with numerous labeled cells being evident in these regions in the A2AR-tag mouse. Importantly, we also identified the presence of a few but clearly labeled cells in heterogeneous brain regions where A2AR expression has not previously been unambiguously detected, including the lateral septum, hippocampus, amygdala, cerebral cortex, and gigantocellular reticular nucleus. The A2AR-tag mouse represents a novel useful genetic tool for monitoring the expression of A2AR and dissecting its functions in brain regions other than the striatum.
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Affiliation(s)
- Muran Wang
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Zewen Li
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yue Song
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Qiuqin Sun
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Lu Deng
- Department of Neurology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou, China
| | - Zhiqing Lin
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Yang Zeng
- Shanghai Pregen Biotechnology Co., Ltd., Shanghai, China
| | - Chunhong Qiu
- Shanghai Pregen Biotechnology Co., Ltd., Shanghai, China
| | - Jingjing Lin
- Department of Neurology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou, China
- Key Laboratory of Structural Malformations in Children of Zhejiang Province, Wenzhou, China
| | - Hui Guo
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
| | - Jiangfan Chen
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
- Jiangfan Chen,
| | - Wei Guo
- The Molecular Neuropharmacology Laboratory and the Eye-Brain Research Center, The State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou Medical University, Wenzhou, China
- *Correspondence: Wei Guo,
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Addressing the Neuroprotective Actions of Coffee in Parkinson’s Disease: An Emerging Nutrigenomic Analysis. Antioxidants (Basel) 2022; 11:antiox11081587. [PMID: 36009304 PMCID: PMC9405141 DOI: 10.3390/antiox11081587] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/17/2022] Open
Abstract
Caffeine is one of the predominant dietary components and psychostimulants present in coffee, a widely appreciated beverage. Corroborating epidemiological and laboratory evidence have suggested an inverse association between the dietary intakes of coffee and the risk of Parkinson’s Disease (PD). Growing attention has been paid to the impact of coffee consumption and genetic susceptibility to PD pathogenesis. Coffee is believed to play prominent roles in mediating the gene makeup and influencing the onset and progression of PD. The current review documents a current discovery of the coffee × gene interaction for the protective management of PD. The evidence underlying its potent impacts on the adenosine receptors (A2AR), estrogen receptors (ESR), heme oxygenase (HO), toxicant responsive genes, nitric oxide synthase (NOS), cytochrome oxidase (Cox), familial parkinsonism genetic susceptibility loci, bone marrow stromal cell antigen 1 (BST1), glutamate receptor gene and apolipoprotein E (APOE) genotype expressions is outlined. Furthermore, the neuroprotective mechanisms of coffee for the amelioration of PD are elucidated.
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Zhang N, Zhao C, Zhang X, Cui X, Zhao Y, Yang J, Gao X. Growth arrest-specific 2 protein family: Structure and function. Cell Prolif 2020; 54:e12934. [PMID: 33103301 PMCID: PMC7791176 DOI: 10.1111/cpr.12934] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Revised: 09/29/2020] [Accepted: 10/03/2020] [Indexed: 12/15/2022] Open
Abstract
Members of the growth arrest–specific 2 (GAS2) protein family consist of a putative actin‐binding (CH) domain and a microtubule‐binding (GAR) domain and are considered miniversions of spectraplakins. There are four members in the GAS2 family, viz. GAS2, GAS2L1, GAS2L2 and GAS2L3. Although GAS2 is defined as a family of growth arrest–specific proteins, the significant differences in the expression patterns, interaction characteristics and biological issues or diseases among the different GAS2 family members have not been systemically reviewed to date. Therefore, we summarized the available evidence on the structures and functions of GAS2 family members. This review facilitates a comprehensive molecular understanding of the involvement of the GAS2 family members in an array of biological processes, including cytoskeleton reorganization, cell cycle, apoptosis and cancer development.
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Affiliation(s)
- Nan Zhang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Chunyan Zhao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xinxin Zhang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xiaoteng Cui
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China.,Laboratory of Neuro-Oncology, Tianjin Neurological Institute, Department of Neurosurgery, Tianjin Medical University General Hospital and Key Laboratory of Neurotrauma, Variation, and Regeneration, Ministry of Education and Tianjin Municipal Government, Tianjin, China
| | - Yan Zhao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Jie Yang
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
| | - Xingjie Gao
- Department of Biochemistry and Molecular Biology, Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China.,Key Laboratory of Immune Microenvironment and Disease, Ministry of Education, Key Laboratory of Cellular and Molecular Immunology in Tianjin, Excellent Talent Project, Tianjin Medical University, Tianjin, China
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Lack of GAS2L2 Causes PCD by Impairing Cilia Orientation and Mucociliary Clearance. Am J Hum Genet 2019; 104:229-245. [PMID: 30665704 DOI: 10.1016/j.ajhg.2018.12.009] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/14/2018] [Indexed: 01/01/2023] Open
Abstract
Primary ciliary dyskinesia (PCD) is a genetic disorder in which impaired ciliary function leads to chronic airway disease. Exome sequencing of a PCD subject identified an apparent homozygous frameshift variant, c.887_890delTAAG (p.Val296Glyfs∗13), in exon 5; this frameshift introduces a stop codon in amino acid 308 of the growth arrest-specific protein 2-like 2 (GAS2L2). Further genetic screening of unrelated PCD subjects identified a second proband with a compound heterozygous variant carrying the identical frameshift variant and a large deletion (c.867_∗343+1207del; p.?) starting in exon 5. Both individuals had clinical features of PCD but normal ciliary axoneme structure. In this research, using human nasal cells, mouse models, and X.laevis embryos, we show that GAS2L2 is abundant at the apical surface of ciliated cells, where it localizes with basal bodies, basal feet, rootlets, and actin filaments. Cultured GAS2L2-deficient nasal epithelial cells from one of the affected individuals showed defects in ciliary orientation and had an asynchronous and hyperkinetic (GAS2L2-deficient = 19.8 Hz versus control = 15.8 Hz) ciliary-beat pattern. These results were recapitulated in Gas2l2-/- mouse tracheal epithelial cell (mTEC) cultures and in X. laevis embryos treated with Gas2l2 morpholinos. In mice, the absence of Gas2l2 caused neonatal death, and the conditional deletion of Gas2l2 impaired mucociliary clearance (MCC) and led to mucus accumulation. These results show that a pathogenic variant in GAS2L2 causes a genetic defect in ciliary orientation and impairs MCC and results in PCD.
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Lai CY, Liu YJ, Lai HL, Chen HM, Kuo HC, Liao YP, Chern Y. The D2 Dopamine Receptor Interferes With the Protective Effect of the A 2A Adenosine Receptor on TDP-43 Mislocalization in Experimental Models of Motor Neuron Degeneration. Front Neurosci 2018; 12:187. [PMID: 29615863 PMCID: PMC5869924 DOI: 10.3389/fnins.2018.00187] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 03/07/2018] [Indexed: 12/13/2022] Open
Abstract
The A2A adenosine receptor (A2AR) and D2 dopamine receptor (D2R) are two G-protein-coupled receptors that can form dimers and negatively regulate their partners. TAR DNA-binding protein (TDP-43) is a nuclear protein that has been implicated in amyotrophic lateral sclerosis (ALS). Mislocalization of TDP-43 from the nucleus to the cytoplasm is an early step of TDP-43 proteinopathy. Our previous studies indicated that A2AR is a potential drug target for ALS because treatment with an A2AR agonist (JMF1907; a T1-11 analog) prevents reactive oxygen species (ROS)-induced TDP-43 mislocalization in a motor neuron cell line (NSC34) and delays motor impairment in a TDP-43 transgenic ALS mouse model. Here, we set out to assess whether activation of D2R interferes with the beneficial effects of an A2AR agonist on motor neurons. We first demonstrated that A2AR and D2R are both located in motor neurons of mouse and human spinal cords and human iPSC-derived motor neurons. Expression of A2AR and D2R in NSC34 cells led to dimer formation without affecting the binding affinity of A2AR toward T1-11. Importantly, activation of D2R reduced T1-11-mediated activation of cAMP/PKA signaling and subsequent inhibition of TDP-43 mislocalization in NSC34 cells. Treatment with quinpirole (a D2 agonist) blunted the rescuing effect of T1-11 on TDP-43 mislocalization and impaired grip strength in a mouse model of ALS. Our findings suggest that D2R activation may limit the beneficial responses of an A2AR agonist in motor neurons and may have an important role in ALS pathogenesis.
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Affiliation(s)
- Chia-You Lai
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yu-Ju Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hsing-Lin Lai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hui-Mei Chen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Hung-Chi Kuo
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Ping Liao
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Górnikiewicz B, Ronowicz A, Madanecki P, Sachadyn P. Genome-wide DNA methylation profiling of the regenerative MRL/MpJ mouse and two normal strains. Epigenomics 2017; 9:1105-1122. [DOI: 10.2217/epi-2017-0009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Aim: We aimed to identify the pivotal differences in the DNA methylation profiles between the regeneration capable MRL/MpJ mouse and reference mouse strains. Materials & methods: Global DNA methylation profiling was performed in ear pinnae, bone marrow, spleen, liver and heart from uninjured adult females of the MRL/MpJ and C57BL/6J and BALB/c. Results & conclusion: A number of differentially methylated regions (DMRs) distinguishing between the MRL/MpJ mouse and both references were identified. In the ear pinnae, the DMRs were enriched in genes associated with development, inflammation and apoptosis, and in binding sites of transcriptional modulator Smad1. Several DMRs overlapped previously mapped quantitative trait loci of regenerative capability. The results suggest potential epigenetic determinants of regenerative phenomenon.
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Affiliation(s)
- Bartosz Górnikiewicz
- Department of Molecular Biotechnology & Microbiology, Gdańsk University of Technology, Gdańsk, Poland
| | - Anna Ronowicz
- Department of Biology & Pharmaceutical Botany of Medical University of Gdańsk, Gdańsk, Poland
| | - Piotr Madanecki
- Department of Biology & Pharmaceutical Botany of Medical University of Gdańsk, Gdańsk, Poland
| | - Paweł Sachadyn
- Department of Molecular Biotechnology & Microbiology, Gdańsk University of Technology, Gdańsk, Poland
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7
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Chen JF, Lee CF, Chern Y. Adenosine receptor neurobiology: overview. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2015; 119:1-49. [PMID: 25175959 DOI: 10.1016/b978-0-12-801022-8.00001-5] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Adenosine is a naturally occurring nucleoside that is distributed ubiquitously throughout the body as a metabolic intermediary. In the brain, adenosine functions as an important upstream neuromodulator of a broad spectrum of neurotransmitters, receptors, and signaling pathways. By acting through four G-protein-coupled receptors, adenosine contributes critically to homeostasis and neuromodulatory control of a variety of normal and abnormal brain functions, ranging from synaptic plasticity, to cognition, to sleep, to motor activity to neuroinflammation, and cell death. This review begun with an overview of the gene and genome structure and the expression pattern of adenosine receptors (ARs). We feature several new developments over the past decade in our understanding of AR functions in the brain, with special focus on the identification and characterization of canonical and noncanonical signaling pathways of ARs. We provide an update on functional insights from complementary genetic-knockout and pharmacological studies on the AR control of various brain functions. We also highlight several novel and recent developments of AR neurobiology, including (i) recent breakthrough in high resolution of three-dimension structure of adenosine A2A receptors (A2ARs) in several functional status, (ii) receptor-receptor heterodimerization, (iii) AR function in glial cells, and (iv) the druggability of AR. We concluded the review with the contention that these new developments extend and strengthen the support for A1 and A2ARs in brain as therapeutic targets for neurologic and psychiatric diseases.
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Affiliation(s)
- Jiang-Fan Chen
- Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA.
| | - Chien-fei Lee
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Yijuang Chern
- Division of Neuroscience, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
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Chiu GS, Darmody PT, Walsh JP, Moon ML, Kwakwa KA, Bray JK, McCusker RH, Freund GG. Adenosine through the A2A adenosine receptor increases IL-1β in the brain contributing to anxiety. Brain Behav Immun 2014; 41:218-31. [PMID: 24907587 PMCID: PMC4167209 DOI: 10.1016/j.bbi.2014.05.018] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Revised: 05/21/2014] [Accepted: 05/22/2014] [Indexed: 02/03/2023] Open
Abstract
Anxiety is one of the most commonly reported psychiatric conditions, but its pathogenesis is poorly understood. Ailments associated with activation of the innate immune system, however, are increasingly linked to anxiety disorders. In adult male mice, we found that adenosine doubled caspase-1 activity in brain by a pathway reliant on ATP-sensitive potassium (KATP) channels, protein kinase A (PKA) and the A2A adenosine receptor (AR). In addition, adenosine-dependent activation of caspase-1 increased interleukin (IL)-1β in the brain by 2-fold. Peripheral administration of adenosine in wild-type (WT) mice led to a 2.3-fold increase in caspase-1 activity in the amygdala and to a 33% and 42% reduction in spontaneous locomotor activity and food intake, respectively, that were not observed in caspase-1 knockout (KO), IL-1 receptor type 1 (IL-1R1) KO and A2A AR KO mice or in mice administered a caspase-1 inhibitor centrally. Finally, adenosine administration increased anxiety-like behaviors in WT mice by 28% in the open field test and by 55% in the elevated zero-maze. Caspase-1 KO mice, IL-1R1 KO mice, A2A AR KO mice and WT mice treated with the KATP channel blocker, glyburide, were resistant to adenosine-induced anxiety-like behaviors. Thus, our results indicate that adenosine can act as an anxiogenic by activating caspase-1 and increasing IL-1β in the brain.
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Affiliation(s)
- Gabriel S Chiu
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Patrick T Darmody
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - John P Walsh
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Morgan L Moon
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Kristin A Kwakwa
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Julie K Bray
- Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA
| | - Robert H McCusker
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA; Department of Animal Sciences, University of Illinois, Urbana, IL, USA
| | - Gregory G Freund
- Division of Nutritional Sciences, University of Illinois, Urbana, IL, USA; Department of Pathology, Program in Integrative Immunology and Behavior, University of Illinois, Urbana, IL, USA; Department of Animal Sciences, University of Illinois, Urbana, IL, USA.
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Huang PC, Hsiao YT, Kao SY, Chen CF, Chen YC, Chiang CW, Lee CF, Lu JC, Chern Y, Wang CT. Adenosine A(2A) receptor up-regulates retinal wave frequency via starburst amacrine cells in the developing rat retina. PLoS One 2014; 9:e95090. [PMID: 24777042 PMCID: PMC4002430 DOI: 10.1371/journal.pone.0095090] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Accepted: 03/23/2014] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Developing retinas display retinal waves, the patterned spontaneous activity essential for circuit refinement. During the first postnatal week in rodents, retinal waves are mediated by synaptic transmission between starburst amacrine cells (SACs) and retinal ganglion cells (RGCs). The neuromodulator adenosine is essential for the generation of retinal waves. However, the cellular basis underlying adenosine's regulation of retinal waves remains elusive. Here, we investigated whether and how the adenosine A(2A) receptor (A(2A)R) regulates retinal waves and whether A(2A)R regulation of retinal waves acts via presynaptic SACs. METHODOLOGY/PRINCIPAL FINDINGS We showed that A(2A)R was expressed in the inner plexiform layer and ganglion cell layer of the developing rat retina. Knockdown of A(2A)R decreased the frequency of spontaneous Ca²⁺ transients, suggesting that endogenous A(2A)R may up-regulate wave frequency. To investigate whether A(2A)R acts via presynaptic SACs, we targeted gene expression to SACs by the metabotropic glutamate receptor type II promoter. Ca²⁺ transient frequency was increased by expressing wild-type A(2A)R (A2AR-WT) in SACs, suggesting that A(2A)R may up-regulate retinal waves via presynaptic SACs. Subsequent patch-clamp recordings on RGCs revealed that presynaptic A(2A)R-WT increased the frequency of wave-associated postsynaptic currents (PSCs) or depolarizations compared to the control, without changing the RGC's excitability, membrane potentials, or PSC charge. These findings suggest that presynaptic A(2A)R may not affect the membrane properties of postsynaptic RGCs. In contrast, by expressing the C-terminal truncated A(2A)R mutant (A(2A)R-ΔC) in SACs, the wave frequency was reduced compared to the A(2A)R-WT, but was similar to the control, suggesting that the full-length A(2A)R in SACs is required for A(2A)R up-regulation of retinal waves. CONCLUSIONS/SIGNIFICANCE A(2A)R up-regulates the frequency of retinal waves via presynaptic SACs, requiring its full-length protein structure. Thus, by coupling with the downstream intracellular signaling, A(2A)R may have a great capacity to modulate patterned spontaneous activity during neural circuit refinement.
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Affiliation(s)
- Pin-Chien Huang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
| | - Yu-Tien Hsiao
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
| | - Shao-Yen Kao
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Ching-Feng Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
| | - Yu-Chieh Chen
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chung-Wei Chiang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
- Department of Life Science, National Taiwan University, Taipei, Taiwan
| | - Chien-fei Lee
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Juu-Chin Lu
- Department of Physiology and Pharmacology, College of Medicine, Chang Gung University, Tao-Yuan, Taiwan
| | - Yijuang Chern
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Chih-Tien Wang
- Institute of Molecular and Cellular Biology, National Taiwan University, Taipei, Taiwan
- Department of Life Science, National Taiwan University, Taipei, Taiwan
- Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan
- Genome and Systems Biology Degree Program, National Taiwan University, Taipei, Taiwan
- * E-mail:
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