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Khandelwal N, Kulkarni A, Ahmed NI, Harper M, Konopka G, Gibson JR. FOXP1 regulates the development of excitatory synaptic inputs onto striatal neurons and induces phenotypic reversal with reinstatement. SCIENCE ADVANCES 2024; 10:eadm7039. [PMID: 38701209 PMCID: PMC11068015 DOI: 10.1126/sciadv.adm7039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/01/2024] [Indexed: 05/05/2024]
Abstract
Long-range glutamatergic inputs originating from the cortex and thalamus are indispensable for striatal development, providing the foundation for motor and cognitive functions. Despite their significance, transcriptional regulation governing these inputs remains largely unknown. We investigated the role of a transcription factor encoded by a high-risk autism-associated gene, FOXP1, in sculpting glutamatergic inputs onto spiny projection neurons (SPNs) within the striatum. We find a neuron subtype-specific role of FOXP1 in strengthening and maturing glutamatergic inputs onto dopamine receptor 2-expressing SPNs (D2 SPNs). We also find that FOXP1 promotes synaptically driven excitability in these neurons. Using single-nuclei RNA sequencing, we identify candidate genes that mediate these cell-autonomous processes through postnatal FOXP1 function at the post-synapse. Last, we demonstrate that postnatal FOXP1 reinstatement rescues electrophysiological deficits, cell type-specific gene expression changes, and behavioral phenotypes. Together, this study enhances our understanding of striatal circuit development and provides proof of concept for a therapeutic approach for FOXP1 syndrome and other neurodevelopmental disorders.
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Affiliation(s)
- Nitin Khandelwal
- Department of Neuroscience and Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Ashwinikumar Kulkarni
- Department of Neuroscience and Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Newaz I. Ahmed
- Department of Neuroscience and Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Matthew Harper
- Department of Neuroscience and Peter O’Donnell Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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2
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Fallahnezhad S, Ghorbani-Taherdehi F, Sahebkar A, Nadim A, Kafashzadeh M, Kafashzadeh M, Gorji-Valokola M. Potential neuroprotective effect of nanomicellar curcumin on learning and memory functions following subacute exposure to bisphenol A in adult male rats. Metab Brain Dis 2023; 38:2691-2720. [PMID: 37843661 DOI: 10.1007/s11011-023-01257-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 06/22/2023] [Indexed: 10/17/2023]
Abstract
Bisphenol A (BPA) is an endocrine-disrupting chemical commonly utilized in the manufacture of plastics, which may cause damage to brain tissue. Curcumin is a phytochemical with protective effects against neurological and mental diseases. The purpose of this research was to evaluate whether nanomicellar curcumin (NmCur) might protect rats against BPA-induced learning and memory deficits. After determining the proper dose of BPA, the animals were randomly divided into 8 groups (8 rats in each group) receiving dextrose 5% (as vehicle of NmCur) (Dex), sesame oil (as vehicle of BPA) (Sea), Sea plus Dex, NmCur (50 mg/kg), BPA (50 mg/kg), and 50 mg/kg BPA plus 10, 25, and 50 mg/kg NmCur groups, respectively. Behavioral tests performed using passive avoidance training (PAT), open-field (OF), and Morris water maze (MWM) tests. The expression of oxidative stress markers, proinflammatory cytokines, oxidative stress-scavenging enzymes, glutamate receptors, and MAPK and memory-related proteins was measured in rat hippocampus and cortical tissues. BPA up-regulated ROS, MDA, TNF-α, IL-6, IL-1β, SOD, GST, p-P38, and p-JNK levels; however, it down-regulated GSH, GPx, GR, CAT, p-AKT, p-ERK1/2, p-NR1, p-NR2A, p-NR2B, p-GluA1, p-CREB, and BDNF levels. BPA decreased step-through latency (STL) and peripheral and total, but not central, locomotor activity. It increased the time to find the hidden platform, the mean of escape latency time, and the traveled distance in the target quadrant, but decreased the time spent in the target quadrant. The combination of BPA (50 mg/kg) and NmCur (25 and 50 mg/kg) reversed all of BPA's adverse effects. Therefore, NmCur exhibited neuroprotective effects against subacute BPA-caused learning and memory impairment.
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Affiliation(s)
- Somaye Fallahnezhad
- Nervous System Stem Cell Research Center, Semnan University of Medical Sciences, Semnan, Iran
- Department of Anatomical Sciences, School of Medicine, Semnan University of Medical Sciences, Semnan, Iran
| | - Faezeh Ghorbani-Taherdehi
- Department of Anatomy and Cell Biology, School of Medicine, Esfahan University of Medical Sciences, Esfahan, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
- Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Azade Nadim
- Department of Pharmaceutics, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehrnaz Kafashzadeh
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Mehrnoosh Kafashzadeh
- Cellular and Molecular Research Center, Sabzevar University of Medical Sciences, Sabzevar, Iran
| | - Mahmoud Gorji-Valokola
- Department of Pharmacology, Brain and Spinal Injury Repair Research Center, Tehran University of Medical Science, Tehran, Iran.
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
- Stem Cell Biology Research Center, Yazd Reproductive Sciences Institute, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
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3
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Khandelwal N, Kulkarni A, Ahmed NI, Harper M, Konopka G, Gibson J. FOXP1 regulates the development of excitatory synaptic inputs onto striatal neurons and induces phenotypic reversal with reinstatement. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.23.563675. [PMID: 37961477 PMCID: PMC10634768 DOI: 10.1101/2023.10.23.563675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Long-range glutamatergic inputs from the cortex and thalamus are critical for motor and cognitive processing in the striatum. Transcription factors that orchestrate the development of these inputs are largely unknown. We investigated the role of a transcription factor and high-risk autism-associated gene, FOXP1, in the development of glutamatergic inputs onto spiny projection neurons (SPNs) in the striatum. We find that FOXP1 robustly drives the strengthening and maturation of glutamatergic input onto dopamine receptor 2-expressing SPNs (D2 SPNs) but has a comparatively milder effect on D1 SPNs. This process is cell-autonomous and is likely mediated through postnatal FOXP1 function at the postsynapse. We identified postsynaptic FOXP1-regulated transcripts as potential candidates for mediating these effects. Postnatal reinstatement of FOXP1 rescues electrophysiological deficits, reverses gene expression alterations resulting from embryonic deletion, and mitigates behavioral phenotypes. These results provide support for a possible therapeutic approach for individuals with FOXP1 syndrome.
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4
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Piniella D, Zafra F. Functional crosstalk of the glycine transporter GlyT1 and NMDA receptors. Neuropharmacology 2023; 232:109514. [PMID: 37003571 DOI: 10.1016/j.neuropharm.2023.109514] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 03/10/2023] [Accepted: 03/20/2023] [Indexed: 04/03/2023]
Abstract
NMDA-type glutamate receptors (NMDARs) constitute one of the main glutamate (Glu) targets in the central nervous system and are involved in synaptic plasticity, which is the molecular substrate of learning and memory. Hypofunction of NMDARs has been associated with schizophrenia, while overstimulation causes neuronal death in neurodegenerative diseases or in stroke. The function of NMDARs requires coincidental binding of Glu along with other cellular signals such as neuronal depolarization, and the presence of other endogenous ligands that modulate their activity by allosterism. Among these allosteric modulators are zinc, protons and Gly, which is an obligatory co-agonist. These characteristics differentiate NMDARs from other receptors, and their structural bases have begun to be established in recent years. In this review we focus on the crosstalk between Glu and glycine (Gly), whose concentration in the NMDAR microenvironment is maintained by various Gly transporters that remove or release it into the medium in a regulated manner. The GlyT1 transporter is particularly involved in this task, and has become a target of great interest for the treatment of schizophrenia since its inhibition leads to an increase in synaptic Gly levels that enhances the activity of NMDARs. However, the only drug that has completed phase III clinical trials did not yield the expected results. Notwithstanding, there are additional drugs that continue to be investigated, and it is hoped that knowledge gained from the recently published 3D structure of GlyT1 may allow the rational design of more effective new drugs.
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Affiliation(s)
- Dolores Piniella
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Institute of Health Carlos III (ISCIII), Spain
| | - Francisco Zafra
- Centro de Biología Molecular Severo Ochoa, Facultad de Ciencias, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Madrid, Spain; IdiPAZ, Institute of Health Carlos III (ISCIII), Spain.
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5
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Hu F, Liang W, Zhang L, Wang H, Li Z, Zhou Y. Hyperactivity of basolateral amygdala mediates behavioral deficits in mice following exposure to bisphenol A and its analogue alternative. CHEMOSPHERE 2022; 287:132044. [PMID: 34474391 DOI: 10.1016/j.chemosphere.2021.132044] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/03/2021] [Accepted: 08/25/2021] [Indexed: 06/13/2023]
Abstract
Bisphenol A (BPA) is a known endocrine disruptor and has been gradually replaced in industrial applications by other bisphenols, such as bisphenol S (BPS). However, whether these analogues are any safer for the central nervous system remains elusive. Here, we investigated behavioral impairments in mice after BPA and BPS exposure from postnatal days 21-49 (P21~P49). Results showed that BPA (0.1 and 1 mg/kg/d) and BPS (1 mg/kg/d) impaired emotion and social interaction of mice, while low dose exposure (0.1 mg/kg/d) induced no observable changes on emotion in mice. The behavioral deficits were accompanied by hyperactivation of the basolateral amygdala (BLA), i.e., dose-dependent increase in neuronal firing rates and local field potential power. In addition, glutamate receptors were up-regulated in the BLA, showing the same activation trend after exposure to different doses of BPA and BPS. Taken together, these findings imply that BPA and BPS cause behavioral impairments in juvenile mice by disrupting local neuronal activation in the BLA. Although BPS exerted less adverse effects on mice than BPA at the low dose, it does not appear to be a safe alternative to BPA in regard to brain function after prolonged high-volume exposure.
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Affiliation(s)
- Fan Hu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China.
| | - Weifeng Liang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Linke Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Huan Wang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, People's Republic of China
| | - Zimu Li
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Yifeng Zhou
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, 230027, People's Republic of China
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Hu F, Zhang L, Li T, Wang H, Liang W, Zhou Y. Bisphenol-A Exposure during Gestation and Lactation Causes Visual Perception Deficits in Rat Pups Following a Decrease in Interleukin 1β Expression in the Primary Visual Cortex. Neuroscience 2020; 434:148-160. [PMID: 32222558 DOI: 10.1016/j.neuroscience.2020.03.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/19/2020] [Accepted: 03/21/2020] [Indexed: 10/24/2022]
Abstract
Bisphenol-A (BPA) exposure can affect cognitive functions of rodents and humans. However, whether information inputs for these functions in the brain are perturbed by BPA remains unclear. Here, visual perception in rats was assessed by testing their ability to discriminate between vertical and horizontal grating. We found that BPA exposure (1 mg/kg/day) during gestation and lactation markedly decreased the grating discrimination ability in rat pups (postnatal 21 days). The results of neuronal functions in the primary visual cortex (V1) showed that the orientation selectivity and signal extraction ability and fidelity were notably decreased after BPA exposure. These effects were accompanied by a reduction in synaptic plasticity (i.e., spine density and maturity) in the V1. According to inflammatory factor expression and glial cell morphology, no increase in inflammatory activation was observed after BPA exposure. However, BPA-exposed rat pups exhibited a significant decrease in IL-1β expression in the V1, accompanied by a decline in P38 phosphorylation. After local injection of IL-1β (10 ng/ml) in the V1, these two visual properties recovered to normal levels. Thus, our findings imply that physiological dysfunction of IL-1β may contribute to orientation perception deficits in BPA-exposed rats.
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Affiliation(s)
- Fan Hu
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China.
| | - Linke Zhang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China
| | - Tingting Li
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China
| | - Huan Wang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Weifeng Liang
- School of Food and Biological Engineering, Hefei University of Technology, Hefei, Anhui 230009, People's Republic of China
| | - Yifeng Zhou
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China.
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7
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Wang XG, Zhu DD, Li N, Huang YL, Wang YZ, Zhang T, Wang CM, Wang B, Peng Y, Ge BY, Li S, Zhao J. Scorpion Venom Heat-Resistant Peptide is Neuroprotective against Cerebral Ischemia-Reperfusion Injury in Association with the NMDA-MAPK Pathway. Neurosci Bull 2019; 36:243-253. [PMID: 31502213 DOI: 10.1007/s12264-019-00425-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 06/03/2019] [Indexed: 12/19/2022] Open
Abstract
Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Our previous studies have shown that SVHRP is neuroprotective in models of Alzheimer's disease and Parkinson's disease. The present study aimed to explore the potential neuroprotective effects of SVHRP on cerebral ischemia/reperfusion (I/R) injury, using a mouse model of middle cerebral artery occlusion/reperfusion (MCAO/R) and a cellular model of oxygen-glucose deprivation/reoxygenation (OGD/R). Our results showed that SVHRP treatment decreased the neurological deficit scores, edema formation, infarct volume and neuronal loss in the MCAO/R mice, and protected primary neurons against OGD/R insult. SVHRP pretreatment suppressed the alterations in protein levels of N-methyl-D-aspartate receptors (NMDARs) and phosphorylated p38 MAPK as well as some proinflammatory factors in both the animal and cellular models. These results suggest that SVHRP has neuroprotective effects against cerebral I/R injury, which might be associated with inhibition of the NMDA-MAPK-mediated excitotoxicity.
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Affiliation(s)
- Xu-Gang Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China.,National-Local Joint Engineering Research Center for Drug-Research and Development of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116000, China.,The Second Hospital of Dalian Medical University, Dalian, 116023, China
| | - Dan-Dan Zhu
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China.,The Second Hospital of Dalian Medical University, Dalian, 116023, China
| | - Na Li
- National-Local Joint Engineering Research Center for Drug-Research and Development of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116000, China
| | - Yue-Lin Huang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Ying-Zi Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China.,The Second Hospital of Dalian Medical University, Dalian, 116023, China
| | - Ting Zhang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Chen-Mei Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Bin Wang
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Yan Peng
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Bi-Ying Ge
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China
| | - Shao Li
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China. .,National-Local Joint Engineering Research Center for Drug-Research and Development of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116000, China.
| | - Jie Zhao
- Liaoning Provincial Key Laboratory of Cerebral Diseases, Department of Physiology, College of Basic Medical Sciences, Dalian Medical University, Dalian, 116044, China. .,National-Local Joint Engineering Research Center for Drug-Research and Development of Neurodegenerative Diseases, Dalian Medical University, Dalian, 116000, China.
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8
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Metzbower SR, Joo Y, Benavides DR, Blanpied TA. Properties of Individual Hippocampal Synapses Influencing NMDA-Receptor Activation by Spontaneous Neurotransmission. eNeuro 2019; 6:ENEURO.0419-18.2019. [PMID: 31110134 PMCID: PMC6541874 DOI: 10.1523/eneuro.0419-18.2019] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 05/05/2019] [Accepted: 05/12/2019] [Indexed: 12/14/2022] Open
Abstract
NMDA receptor (NMDAR) activation is critical for maintenance and modification of synapse strength. Specifically, NMDAR activation by spontaneous glutamate release has been shown to mediate some forms of synaptic plasticity as well as synaptic development. Interestingly, there is evidence that within individual synapses each release mode may be segregated such that postsynaptically there are distinct pools of responsive receptors. To examine potential regulators of NMDAR activation because of spontaneous glutamate release in cultured hippocampal neurons, we used GCaMP6f imaging at single synapses in concert with confocal and super-resolution imaging. Using these single-spine approaches, we found that Ca2+ entry activated by spontaneous release tends to be carried by GluN2B-NMDARs. Additionally, the amount of NMDAR activation varies greatly both between synapses and within synapses, and is unrelated to spine and synapse size, but does correlate loosely with synapse distance from the soma. Despite the critical role of spontaneous activation of NMDARs in maintaining synaptic function, their activation seems to be controlled factors other than synapse size or synapse distance from the soma. It is most likely that NMDAR activation by spontaneous release influenced variability in subsynaptic receptor position, release site position, vesicle content, and channel properties. Therefore, spontaneous activation of NMDARs appears to be regulated distinctly from other receptor types, notably AMPARs, within individual synapses.
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Affiliation(s)
| | - Yuyoung Joo
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
| | - David R Benavides
- Department of Neurology, University of Maryland School of Medicine, Baltimore, Maryland, 21201
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Takeda A, Shinozaki Y, Kashiwagi K, Ohno N, Eto K, Wake H, Nabekura J, Koizumi S. Microglia mediate non-cell-autonomous cell death of retinal ganglion cells. Glia 2018; 66:2366-2384. [PMID: 30375063 DOI: 10.1002/glia.23475] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 05/23/2018] [Accepted: 05/28/2018] [Indexed: 12/22/2022]
Abstract
Excitotoxicity is well known in the neuronal death in the brain and is also linked to neuronal damages in the retina. Recent accumulating evidence show that microglia greatly affect excitotoxicity in the brain, but their roles in retina have received only limited attention. Here, we report that retinal excitotoxicity is mediated by microglia. To this end, we employed three discrete methods, that is, pharmacological inhibition of microglia by minocycline, pharmacological ablation by an antagonist for colony stimulating factor 1 receptor (PLX5622), and genetic ablation of microglia using Iba1-tTA::DTAtetO/tetO mice. Intravitreal injection of NMDA increased the number of apoptotic retinal ganglion cells (RGCs) followed by reduction in the number of RGCs. Although microglia did not respond to NMDA directly, they became reactive earlier than RGC damages. Inhibition or ablation of microglia protected RGCs against NMDA. We found up-regulation of proinflammatory cytokine genes including Il1b, Il6 and Tnfa, among which Tnfa was selectively blocked by minocycline. PLX5622 also suppressed Tnfa expression. Tumor necrosis factor α (TNFα) signals were restricted in microglia at very early followed by spreading into other cell types. TNFα up-regulation in microglia and other cells were significantly attenuated by minocycline and PLX5622, suggesting a central role of microglia for TNFα induction. Both inhibition of TNFα and knockdown of TNF receptor type 1 by siRNA protected RGCs against NMDA. Taken together, our data demonstrate that a phenotypic change of microglia into a neurotoxic one is a critical event for the NMDA-induced degeneration of RGCs, suggesting an importance of non-cell-autonomous mechanism in the retinal neuronal excitotoxicity.
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Affiliation(s)
- Akiko Takeda
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Youichi Shinozaki
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Kenji Kashiwagi
- Department of Ophthalmology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
| | - Nobuhiko Ohno
- Division of Neurobiology and Bioinformatics, National Institute for Physiological Sciences (NIPS), Aichi, Japan.,Department of Anatomy, Jichi Medical University, Tochigi, Japan
| | - Kei Eto
- Division of Homeostatic Development, NIPS, Aichi, Japan
| | - Hiroaki Wake
- Division of Homeostatic Development, NIPS, Aichi, Japan.,Division of System Neuroscience, Graduate School of Medicine, Kobe University, Hyogo, Japan.,Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama, Japan
| | | | - Schuichi Koizumi
- Department of Neuropharmacology, Interdisciplinary Graduate School of Medicine, University of Yamanashi, Yamanashi, Japan
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10
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Chen Z, Li T, Zhang L, Wang H, Hu F. Bisphenol A exposure remodels cognition of male rats attributable to excitatory alterations in the hippocampus and visual cortex. Toxicology 2018; 410:132-141. [PMID: 30312744 DOI: 10.1016/j.tox.2018.10.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/28/2018] [Accepted: 10/07/2018] [Indexed: 12/16/2022]
Abstract
Bisphenol A, an environmental xenoestrogen, has been shown sex-specific adverse effects on cognitive function of rodents. However, the specific mechanisms underlying these outcomes remain elusive, limiting our understanding the differences in behavioral impairments due to BPA exposure between genders in humans. The present study chose the juvenile stage (with a stable estrogen level) as the exposure window to explore BPA effects on cognitive behaviors of male and female Sprague-Dawley (SD) rats and related mechanisms. Three dosages of BPA (0.04, 0.4 and 4 mg/kg/day) were chose to make BPA-exposed models. Especially, the mid-dose for rats was close to the current reference daily limit for human exposure given by the U.S. Environmental Protection Agency. Our results showed that male but not female juvenile rats had a marked decline in spatial memory after 0.4 mg/kg/day BPA exposure, which accompanied with downregulation of glutamate receptor (NR2) expression in their hippocampus and primary visual cortex (V1). In the high-dose BPA exposed groups (4 mg/kg/day), there was not only a deficit of spatial memory, but also an anxiety-like behavior of male rats. Additionally, those rats had a significant decline in spine density of pyramidal neurons and a decreased expression of glutamate receptor subtypes (NR2 and GluR1) in the hippocampus. Importantly, such impairments in the hippocampus of male rats were associated with a decrease of glutamate receptor (NR2) expression in the V1, which could perturb the visual information inputs. To some extent, altered ERβ expression within their hypothalamus could contribute to the anxiety-like behavior after high-dose BPA exposure. However, the low-dose BPA exposed juvenile rats didn't present any structural and behavioral changes in our present study. Those results suggests that BPA exerts dose dependent and gender-specific effects on the cognition of juvenile animals. Our findings shed light on mechanisms underlying BPA effects on the juvenile animals.
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Affiliation(s)
- Zhi Chen
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Tingting Li
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Linke Zhang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China
| | - Huan Wang
- CAS Key Laboratory of Brain Function and Diseases, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027, People's Republic of China
| | - Fan Hu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui, 230009, People's Republic of China.
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11
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Rahman A, Rao MS, Khan KM. Intraventricular infusion of quinolinic acid impairs spatial learning and memory in young rats: a novel mechanism of lead-induced neurotoxicity. J Neuroinflammation 2018; 15:263. [PMID: 30217162 PMCID: PMC6137743 DOI: 10.1186/s12974-018-1306-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/04/2018] [Indexed: 12/20/2022] Open
Abstract
Background Lead (Pb), a heavy metal, and quinolinic acid (QA), a metabolite of the kynurenine pathway of tryptophan metabolism, are known neurotoxicants. Both Pb and QA impair spatial learning and memory. Pb activates astrocytes and microglia, which in turn induce the synthesis of QA. We hypothesized increased QA production in response to Pb exposure as a novel mechanism of Pb-neurotoxicity. Methods Two experimental paradigms were used. In experiment one, Wistar rat pups were exposed to Pb via their dams’ drinking water from postnatal day 1 to 21. Control group was given regular water. In the second protocol, QA (9 mM) or normal saline (as Vehicle Control) was infused into right lateral ventricle of 21-day old rats for 7 days using osmotic pumps. Learning and memory were assessed by Morris water maze test on postnatal day 30 or 45 in both Pb- and QA-exposed rats. QA levels in the Pb exposed rats were measured in blood by ELISA and in the brain by immunohistochemistry on postnatal days 45 and 60. Expression of various molecules involved in learning and memory was analyzed by Western blot. Means of control and experimental groups were compared with two-way repeated measure ANOVA (learning) and t test (all other variables). Results Pb exposure increased QA level in the blood (by ~ 58%) and increased (p < 0.05) the number of QA-immunoreactive cells in the cortex, and CA1, CA3 and dentate gyrus regions of the hippocampus, compared to control rats. In separate experiments, QA infusion impaired learning and short-term memory similar to Pb. PSD-95, PP1, and PP2A were decreased (p < 0.05) in the QA-infused rats, whereas tau phosphorylation was increased, compared to vehicle infused rats. Conclusion Putting together the results of the two experimental paradigms, we propose that increased QA production in response to Pb exposure is a novel mechanism of Pb-induced neurotoxicity.
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Affiliation(s)
- Abdur Rahman
- Department of Food Science and Nutrition, College of Life Sciences, Kuwait University, Kuwait City, Kuwait.
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Khalid M Khan
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
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12
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Kiffer F, Howe AK, Carr H, Wang J, Alexander T, Anderson JE, Groves T, Seawright JW, Sridharan V, Carter G, Boerma M, Allen AR. Late effects of 1H irradiation on hippocampal physiology. LIFE SCIENCES IN SPACE RESEARCH 2018; 17:51-62. [PMID: 29753414 PMCID: PMC7063743 DOI: 10.1016/j.lssr.2018.03.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 03/07/2018] [Accepted: 03/10/2018] [Indexed: 05/21/2023]
Abstract
NASA's Missions to Mars and beyond will expose flight crews to potentially dangerous levels of charged-particle radiation. Of all charged nuclei, 1H is the most abundant charged particle in both the galactic cosmic ray (GCR) and solar particle event (SPE) spectra. There are currently no functional spacecraft shielding materials that are able to mitigate the charged-particle radiation encountered in space. Recent studies have demonstrated cognitive injuries due to high-dose 1H exposures in rodents. Our study investigated the effects of 1H irradiation on neuronal morphology in the hippocampus of adult male mice. 6-month-old mice received whole-body exposure to 1H at 0.5 and 1 Gy (150 MeV/n; 0.35-0.55 Gy/min) at NASA's Space Radiation Laboratory in Upton, NY. At 9-months post-irradiation, we tested each animal's open-field exploratory performance. After sacrifice, we dissected the brains along the midsagittal plane, and then either fixed or dissected further and snap-froze them. Our data showed that exposure to 0.5 Gy or 1 Gy 1H significantly increased animals' anxiety behavior in open-field testing. Our micromorphometric analyses revealed significant decreases in mushroom spine density and dendrite morphology in the Dentate Gyrus, Cornu Ammonis 3 and 1 of the hippocampus, and lowered expression of synaptic markers. Our data suggest 1H radiation significantly increased exploration anxiety and modulated the dendritic spine and dendrite morphology of hippocampal neurons at a dose of 0.5 or 1 Gy.
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Affiliation(s)
- Frederico Kiffer
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Alexis K Howe
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Hannah Carr
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Jing Wang
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Tyler Alexander
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Julie E Anderson
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Thomas Groves
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - John W Seawright
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Vijayalakshmi Sridharan
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Gwendolyn Carter
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Marjan Boerma
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
| | - Antiño R Allen
- Division of Radiation Health at the University of Arkansas for Medical Sciences, 4301 West Markham, Suite 441B-2, Little Rock, AR 72205, United States; Department of Pharmaceutical Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States; Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, AR 72205, United States.
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Increasing the GluN2A/GluN2B Ratio in Neurons of the Mouse Basal and Lateral Amygdala Inhibits the Modification of an Existing Fear Memory Trace. J Neurosci 2017; 36:9490-504. [PMID: 27605622 DOI: 10.1523/jneurosci.1743-16.2016] [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: 05/27/2016] [Accepted: 07/28/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Reconsolidation updating is a form of memory modification in which an existing memory can become destabilized upon retrieval and subsequently be modified via protein-synthesis-dependent reconsolidation. However, not all memories appear to destabilize upon retrieval and thus are not modifiable via reconsolidation updating approaches and the neurobiological basis for this remains poorly understood. Here, we report that auditory fear memories created with 10 tone-shock pairings are resistant to retrieval-dependent memory destabilization and are associated with an increase in the synaptic GluN2A/GluN2B ratio in neurons of the basal and lateral amygdala (BLA) compared with weaker fear memories created via one or three tone-shock pairings. To increase the GluN2A/GluN2B ratio after learning, we generated a line of mice that expresses an inducible and doxycycline-dependent GFP-GluN2A transgene specifically in α-CaMKII-positive neurons. Our findings indicate that increasing the GluN2A/GluN2B ratio in BLA α-CaMKII-positive neurons after a weak fear memory has consolidated inhibits retrieval-dependent memory destabilization and modification of the fear memory trace. This was associated with a reduction in retrieval-dependent AMPA receptor trafficking, as evidenced by a reduction in retrieval-dependent phosphorylation of GluR1 at serine-845. In addition, we determined that increasing the GluN2A/GluN2B ratio before fear learning significantly impaired long term memory consolidation, whereas short-term memory remained unaltered. An increase in the GluN2A/GluN2B ratio after fear learning had no influence on fear extinction or expression. Our results underscore the importance of NMDAR subunit composition for memory destabilization and suggest a mechanism for why some memories are resistant to modification. SIGNIFICANCE STATEMENT Memory modification using reconsolidation updating is being examined as one of the potential treatment approaches for attenuating maladaptive memories associated with emotional disorders. However, studies have shown that, whereas weak memories can be modified using reconsolidation updating, strong memories can be resistant to this approach. Therefore, treatments targeting the reconsolidation process are unlikely to be clinically effective unless methods are devised to enhance retrieval-dependent memory destabilization. Currently, little is known about the cellular and molecular events that influence the induction of reconsolidation updating. Here, we determined that an increase in the GluN2A/GluN2B ratio interferes with retrieval-dependent memory destabilization and inhibits the initiation of reconsolidation updating.
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Hu F, Li T, Gong H, Chen Z, Jin Y, Xu G, Wang M. Bisphenol A Impairs Synaptic Plasticity by Both Pre- and Postsynaptic Mechanisms. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2017; 4:1600493. [PMID: 28852612 PMCID: PMC5566242 DOI: 10.1002/advs.201600493] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/10/2017] [Indexed: 05/30/2023]
Abstract
Bisphenol A (BPA), an environmental xenoestrogen, has been reported to induce learning and memory impairments in rodent animals. However, effects of BPA exposure on synaptic plasticity and the underlying physiological mechanisms remain elusive. Our behavioral and electrophysiological analyses show that BPA obviously perturbs hippocampal spatial memory of juvenile Sprague-Dawley rats after four weeks exposure, with significantly impaired long-term potentiation (LTP) in the hippocampus. These effects involve decreased spine density of pyramidal neurons, especially the apical dendritic spine. Further presynaptic findings show an overt inhibition of pulse-paired facilitation during electrophysiological recording, which suggest the decrease of presynaptic transmitter release and is consistent with reduced production of presynaptic glutamate after BPA exposure. Meanwhile, LTP-related glutamate receptors, NMDA receptor 2A (NR2A) and AMPA receptor 1 (GluR1), are significantly downregulated in BPA-exposed rats. Excitatory postsynaptic currents (EPSCs) results also show that EPSCNMDA, but not EPSCAMPA, is declined by 40% compared to the baseline in BPA-perfused brain slices. Taken together, these findings reveal that juvenile BPA exposure has negative effects on synaptic plasticity, which result from decreases in dendritic spine density and excitatory synaptic transmission. Importantly, this study also provides new insights into the dynamics of BPA-induced memory deterioration during the whole life of rats.
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Affiliation(s)
- Fan Hu
- School of Food Science and EngineeringHefei University of TechnologyHefeiAnhui230009P. R. China
| | - Tingting Li
- School of Food Science and EngineeringHefei University of TechnologyHefeiAnhui230009P. R. China
| | - Huarui Gong
- CAS Key Laboratory of Brain Function and DiseasesSchool of Life SciencesUniversity of Science and Technology of ChinaHefeiAnhui230027P. R. China
| | - Zhi Chen
- School of Food Science and EngineeringHefei University of TechnologyHefeiAnhui230009P. R. China
| | - Yan Jin
- CAS Key Laboratory of Brain Function and DiseasesSchool of Life SciencesUniversity of Science and Technology of ChinaHefeiAnhui230027P. R. China
| | - Guangwei Xu
- CAS Key Laboratory of Brain Function and DiseasesSchool of Life SciencesUniversity of Science and Technology of ChinaHefeiAnhui230027P. R. China
| | - Ming Wang
- CAS Key Laboratory of Brain Function and DiseasesSchool of Life SciencesUniversity of Science and Technology of ChinaHefeiAnhui230027P. R. China
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15
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Holm TH, Isaksen TJ, Glerup S, Heuck A, Bøttger P, Füchtbauer EM, Nedergaard S, Nyengaard JR, Andreasen M, Nissen P, Lykke-Hartmann K. Cognitive deficits caused by a disease-mutation in the α3 Na(+)/K(+)-ATPase isoform. Sci Rep 2016; 6:31972. [PMID: 27549929 PMCID: PMC4994072 DOI: 10.1038/srep31972] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 08/01/2016] [Indexed: 12/01/2022] Open
Abstract
The Na+/K+-ATPases maintain Na+ and K+ electrochemical gradients across the plasma membrane, a prerequisite for electrical excitability and secondary transport in neurons. Autosomal dominant mutations in the human ATP1A3 gene encoding the neuron-specific Na+/K+-ATPase α3 isoform cause different neurological diseases, including rapid-onset dystonia-parkinsonism (RDP) and alternating hemiplegia of childhood (AHC) with overlapping symptoms, including hemiplegia, dystonia, ataxia, hyperactivity, epileptic seizures, and cognitive deficits. Position D801 in the α3 isoform is a mutational hotspot, with the D801N, D801E and D801V mutations causing AHC and the D801Y mutation causing RDP or mild AHC. Despite intensive research, mechanisms underlying these disorders remain largely unknown. To study the genotype-to-phenotype relationship, a heterozygous knock-in mouse harboring the D801Y mutation (α3+/D801Y) was generated. The α3+/D801Y mice displayed hyperactivity, increased sensitivity to chemically induced epileptic seizures and cognitive deficits. Interestingly, no change in the excitability of CA1 pyramidal neurons in the α3+/D801Y mice was observed. The cognitive deficits were rescued by administration of the benzodiazepine, clonazepam, a GABA positive allosteric modulator. Our findings reveal the functional significance of the Na+/K+-ATPase α3 isoform in the control of spatial learning and memory and suggest a link to GABA transmission.
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Affiliation(s)
- Thomas Hellesøe Holm
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark
| | - Toke Jost Isaksen
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark
| | - Simon Glerup
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark
| | - Anders Heuck
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark
| | - Pernille Bøttger
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark
| | | | - Steen Nedergaard
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark
| | - Jens Randel Nyengaard
- Stereology and Electron Microscopy Laboratory, Center for Stochastic Geometry and Advanced Bioimaging, Aarhus University Hospital, Aarhus University, DK-8000 Aarhus, Denmark
| | - Mogens Andreasen
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark
| | - Poul Nissen
- Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus, Denmark.,Danish Research Institute for Translational Neuroscience-DANDRITE, Nordic-EMBL Partnership of Molecular Medicine, Aarhus University, Department of Molecular Biology and Genetics and Department of Biomedicine, DK-8000 Aarhus C, Denmark
| | - Karin Lykke-Hartmann
- Aarhus University, Department of Biomedicine, DK-8000 Aarhus, Denmark.,Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation, Aarhus University, Department of Molecular Biology and Genetics, DK-8000 Aarhus C, Denmark.,Aarhus Institute of Advanced Studies (AIAS), Aarhus University, DK-8000 Aarhus C, Denmark
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16
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Yao G, Yun Y, Sang N. Differential effects between one week and four weeks exposure to same mass of SO2 on synaptic plasticity in rat hippocampus. ENVIRONMENTAL TOXICOLOGY 2016; 31:820-829. [PMID: 25534910 DOI: 10.1002/tox.22093] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/02/2014] [Accepted: 12/07/2014] [Indexed: 06/04/2023]
Abstract
Sulfur dioxide (SO2 ) is a ubiquitous air pollutant. The previous studies have documented the adverse effects of SO2 on nervous system health, suggesting that acutely SO2 inhalation at high concentration may be associated with neurotoxicity and increase risk of hospitalization and mortality of many brain disorders. However, the remarkable features of air pollution exposure are lifelong duration and at low concentration; and it is rarely reported that whether there are different responses on synapse when rats inhaled same mass of SO2 at low concentration with a longer term. In this study, we evaluated the synaptic plasticity in rat hippocampus after exposure to same mass of SO2 at various concentrations and durations (3.5 and 7 mg/m(3) , 6 h/day, for 4 weeks; and 14 and 28 mg/m(3) , 6 h/day, for 1 week). The results showed that the mRNA level of synaptic plasticity marker Arc, glutamate receptors (GRIA1, GRIA2, GRIN1, GRIN2A, and GRIN2B) and the protein expression of memory related kinase p-CaMKпα were consistently inhibited by SO2 both in 1 week and 4 weeks exposure cases; the protein expression of presynaptic marker synaptophysin, postsynaptic density protein 95 (PSD-95), protein kinase A (PKA), and protein kinase C (PKC) were increased in 1 week exposure case, and decreased in 4 weeks exposure case. Our results indicated that SO2 inhalation caused differential synaptic injury in 1 week and 4 weeks exposure cases, and implied the differential effects might result from different PKA- and/or PKC-mediated signal pathway. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 820-829, 2016.
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Affiliation(s)
- Gaoyi Yao
- College of Environment and Resource, Research Center of Environment and Health, Institute of Environmental Science, Shanxi University, Taiyuan, Shanxi, 030006, People's Republic of China
| | - Yang Yun
- College of Environment and Resource, Research Center of Environment and Health, Institute of Environmental Science, Shanxi University, Taiyuan, Shanxi, 030006, People's Republic of China
| | - Nan Sang
- College of Environment and Resource, Research Center of Environment and Health, Institute of Environmental Science, Shanxi University, Taiyuan, Shanxi, 030006, People's Republic of China
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Xie Z, Shi M, Zhang C, Zhao H, Hui H, Zhao G. Ginsenoside Rd Protects Against Cerebral Ischemia-Reperfusion Injury Via Decreasing the Expression of the NMDA Receptor 2B Subunit and its Phosphorylated Product. Neurochem Res 2016; 41:2149-59. [PMID: 27165636 DOI: 10.1007/s11064-016-1930-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Revised: 04/09/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022]
Abstract
Ginsenoside Rd (GSRd) is one of the active ingredients in ginseng. Recent studies have shown that GSRd can protect against cerebral ischemia through several pathways, one of which is mediated by the N-methyl-D-aspartate receptor (NMDAR). In this study, we aimed to investigate the effects of GSRd on the phosphorylation of the NMDAR 2B subunit (NR2B subunit) in cerebral ischemia. Ischemia-reperfusion injury (IRI) models induced by transient middle cerebral artery occlusion (MCAO) and oxygen glucose deprivation (OGD) were used to mimic in vivo or in vitro injury during cerebral ischemia. The models were pretreated or post-treated with GSRd after MCAO or OGD. As a vehicle control, 1,3-propanediol was used. The expression levels of the NR2B subunit and the phosphorylated NR2B subunit were determined using western blotting. GSRd significantly improved the behavior score, infarct volume, and viability of the cultured neurons after ischemia. GSRd inhibited the hyperphosphorylation of NR2B subunit and decreased the expression levels of NR2B subunit in cell membrane but did not change their levels in the total proteins after IRI. GSRd protected Sprague-Dawley rats and cultured neurons from IRI via inhibiting the hyperphosphorylation of NR2B subunit and decreasing its expression levels in cell membrane.
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Affiliation(s)
- Zhen Xie
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.,Department 2 of Neurology, Shaanxi Provincial People's Hospital, Xi'an, China
| | - Ming Shi
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Chen Zhang
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Haibo Zhao
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Hao Hui
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China
| | - Gang Zhao
- Department of Neurology, Xijing Hospital, The Fourth Military Medical University, Xi'an, China.
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18
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Levodopa-Induced Dyskinesia Is Related to Indirect Pathway Medium Spiny Neuron Excitotoxicity: A Hypothesis Based on an Unexpected Finding. PARKINSONS DISEASE 2016; 2016:6461907. [PMID: 27144051 PMCID: PMC4837280 DOI: 10.1155/2016/6461907] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 03/29/2016] [Indexed: 12/31/2022]
Abstract
A serendipitous pharmacogenetic finding links the vulnerability to developing levodopa-induced dyskinesia to the age of onset of Huntington's disease. Huntington's disease is caused by a polyglutamate expansion of the protein huntingtin. Aberrant huntingtin is less capable of binding to a member of membrane-associated guanylate kinase family (MAGUKs): postsynaptic density- (PSD-) 95. This leaves more PSD-95 available to stabilize NR2B subunit carrying NMDA receptors in the synaptic membrane. This results in increased excitotoxicity for which particularly striatal medium spiny neurons from the indirect extrapyramidal pathway are sensitive. In Parkinson's disease the sensitivity for excitotoxicity is related to increased oxidative stress due to genetically determined abnormal metabolism of dopamine or related products. This probably also increases the sensitivity of medium spiny neurons for exogenous levodopa. Particularly the combination of increased oxidative stress due to aberrant dopamine metabolism, increased vulnerability to NMDA induced excitotoxicity, and the particular sensitivity of indirect pathway medium spiny neurons for this excitotoxicity may explain the observed increased prevalence of levodopa-induced dyskinesia.
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19
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Fachim HA, Pereira AC, Iyomasa-Pilon MM, Rosa MLNM. Differential Expression of AMPA Subunits Induced by NMDA Intrahippocampal Injection in Rats. Front Neurosci 2016; 10:32. [PMID: 26912994 PMCID: PMC4753315 DOI: 10.3389/fnins.2016.00032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/26/2016] [Indexed: 11/13/2022] Open
Abstract
Glutamate is involved in excitotoxic mechanisms by interacting with different receptors. Such interactions result in neuronal death associated with several neurodegenerative disorders of the central nervous system (CNS). The aim of this work was to study the time course of changes in the expression of GluR1 and GluR2 subunits of glutamate amino-acid-3-hydroxy-5-methyl-isoxazol-4-propionic acid (AMPA) receptors in rat hippocampus induced by NMDA intrahippocampal injection. Rats were submitted to stereotaxic surgery for NMDA or saline (control) microinjection into dorsal hippocampus and the parameters were evaluated 24 h, 1, 2, and 4 weeks after injection. The extension and efficacy of the NMDA-induced injury were evaluated by Morris water maze (MWM) behavioral test and Nissl staining. The expression of GluR1 and GluR2 receptors, glial fibrillary acidic protein (GFAP), and neuronal marker (NeuN) was analyzed by immunohistochemistry. It was observed the impairment of learning and memory functions, loss of neuronal cells, and glial proliferation in CA1 area of NMDA compared with control groups, confirming the injury efficacy. In addition, NMDA injection induced distinct changes in GluR1 and GluR2 expression over the time. In conclusion, such changes may be related to the complex mechanism triggered in response to NMDA injection resulting in a local injury and in the activation of neuronal plasticity.
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Affiliation(s)
- Helene A Fachim
- Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirao Preto, University of Sao PauloRibeirão Preto, Brazil; Institute of Neuroscience and BehaviorRibeirão Preto, Brazil
| | - Adriana C Pereira
- Department of Biology, Faculty of Philosophy, Sciences and Letters of Ribeirao Preto, University of Sao PauloRibeirão Preto, Brazil; Institute of Neuroscience and BehaviorRibeirão Preto, Brazil
| | | | - Maria L N M Rosa
- Institute of Neuroscience and BehaviorRibeirão Preto, Brazil; Barretos School of Health Sciences, Faculdade de Ciências da Saúde de Barretos Dr. Paulo Prata (FACISB)Barretos, Brazil
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Micu I, Plemel JR, Lachance C, Proft J, Jansen AJ, Cummins K, van Minnen J, Stys PK. The molecular physiology of the axo-myelinic synapse. Exp Neurol 2016; 276:41-50. [DOI: 10.1016/j.expneurol.2015.10.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 01/18/2023]
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21
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Lai Q, Hu P, Li Q, Li X, Yuan R, Tang X, Wang W, Li X, Fan H, Yin X. NMDA receptors promote neurogenesis in the neonatal rat subventricular zone following hypoxic‑ischemic injury. Mol Med Rep 2015; 13:206-12. [PMID: 26548659 PMCID: PMC4686072 DOI: 10.3892/mmr.2015.4501] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/02/2015] [Indexed: 02/06/2023] Open
Abstract
Evidence suggests the involvement of N-methyl-D-aspartate receptors (NMDAR) in the regulation of neurogenesis. Functional properties of NMDAR are strongly influenced by the type of NR2 subunits in the receptor complex. NR2A- and NR2B-containing receptors are expressed in neonatal fore-brain regions, such as the subventricular zone (SVZ). The aim of the present study was to examine the effect of the protein expression of hypoxic-ischemic injury NMDAR subunits 2A and 2B in the SVZ of neonatal rats. Expression of these and other proteins of interest was performed using immunohistochemistry. The results showed that NR2A expression was decreased at 6 h after hypoxic-ischemic injury. By contrast, a significant increase in NR2B expression was observed at 24 h after hypoxic-ischemic injury, induced by the clamping of the right common carotid artery. The functional effect of NMDAR subunits on neurogenesis was also examined by quantifying Nestin and doublecortin (DCX), the microtubule-associated protein expressed only in immature neurons. In addition, the effects of selective non-competitive NMDAR antagonist MK-801 (0.5 mg/kg), NR2B antagonist Ro25-6981 (5 mg/kg), and NR2A antagonist NVP-AAM077 (5 mg/kg) administered 30 min prior to the hypoxic-ischemic injury were examined. The number of Nestin- and DCX-positive cells increased significantly 48 h after hypoxic-ischemic injury, which was reverted by the MK-801 and Ro25-6981 antagonists. Notably, NVP-AAM077 had no significant effect on the expression of Nestin and DCX. In conclusion, the results of the present study demonstrate that hypoxia-ischemia inhibited the expression of NR2A, but promoted the expression of NR2B. Furthermore, NMDAR promoted neurogenesis in the SVZ of neonatal brains.
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Affiliation(s)
- Qingwei Lai
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Peng Hu
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Qingyun Li
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Xinyu Li
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Rui Yuan
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Xiaohong Tang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Wei Wang
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Xiaoquan Li
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Hongbin Fan
- Department of Neurology, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, P.R. China
| | - Xiaoxing Yin
- Department of Clinical Pharmacology, School of Pharmacy, Xuzhou Medical College, Xuzhou, Jiangsu 221004, P.R. China
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22
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Lu W, Fang W, Li J, Zhang B, Yang Q, Yan X, Peng L, Ai H, Wang JJ, Liu X, Luo J, Yang W. Phosphorylation of Tyrosine 1070 at the GluN2B Subunit Is Regulated by Synaptic Activity and Critical for Surface Expression of N-Methyl-D-aspartate (NMDA) Receptors. J Biol Chem 2015; 290:22945-54. [PMID: 26229100 DOI: 10.1074/jbc.m115.663450] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Indexed: 01/13/2023] Open
Abstract
The number and subunit composition of synaptic N-methyl-d-aspartate receptors (NMDARs) play critical roles in synaptic plasticity, learning, and memory and are implicated in neurological disorders. Tyrosine phosphorylation provides a powerful means of regulating NMDAR function, but the underling mechanism remains elusive. In this study we identified a tyrosine site on the GluN2B subunit, Tyr-1070, which was phosphorylated by a proto-oncogene tyrosine-protein (Fyn) kinase and critical for the surface expression of GluN2B-containing NMDARs. The phosphorylation of GluN2B at Tyr-1070 was required for binding of Fyn kinase to GluN2B, which up-regulated the phosphorylation of GluN2B at Tyr-1472. Moreover, our results revealed that the phosphorylation change of GluN2B at Tyr-1070 accompanied the Tyr-1472 phosphorylation and Fyn associated with GluN2B in synaptic plasticity induced by both chemical and contextual fear learning. Taken together, our findings provide a new mechanism for regulating the surface expression of NMDARs with implications for synaptic plasticity.
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Affiliation(s)
- Wen Lu
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Weiqing Fang
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jian Li
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China, Department of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang 310027, China, and
| | - Bin Zhang
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Qian Yang
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xunyi Yan
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Lin Peng
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Heng Ai
- Department of Physiology, Zhejiang Medical College, Hangzhou, Zhejiang 310053, China
| | - Jie-jie Wang
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Xiao Liu
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China
| | - Jianhong Luo
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China,
| | - Wei Yang
- From the Department of Neurobiology, Key Laboratory of Medical Neurobiology (Ministry of Health of China), Collaborative Innovation Center for Brain Science, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310058, China,
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23
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Yao G, Yue H, Yun Y, Sang N. Chronic SO2 inhalation above environmental standard impairs neuronal behavior and represses glutamate receptor gene expression and memory-related kinase activation via neuroinflammation in rats. ENVIRONMENTAL RESEARCH 2015; 137:85-93. [PMID: 25498917 DOI: 10.1016/j.envres.2014.11.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/19/2014] [Accepted: 11/25/2014] [Indexed: 06/04/2023]
Abstract
Sulfur dioxide (SO2), as a ubiquitous air pollutant implicated in the genesis of pulmonary disease, is now being considered to be involved in neurotoxicity and increased risk for hospitalization of brain disorders. However, comparatively little is known about the impact of chronically SO2 inhalation on neuronal function. In the present study, by exposing male Wistar rats to SO2 at 3.50 and 7.00 mg/m(3) (approximately 1225 and 2450 ppb, 4.08-8.16 (24h average concentration) times higher than the EPA standard for environmental air concentrations) or filtered air for 90 days, we investigated the impact of chronic SO2 inhalation on performance in Morris water maze, and probed the accompanying neurobiological effects, including activity-regulated cytoskeletal associated gene (Arc) and glutamate receptor gene expression, memory-related kinase level and inflammatory cytokine release in the hippocampus. Here, we found that SO2 exposure reduced the number of target zone crossings and time spent in the target quadrant during the test session in the spatial memory retention of the Morris water maze. Following the neuro-functional abnormality, we detected that SO2 inhalation reduced the expression of Arc and glutamate receptor subunits (GluR1, GluR2, NR1, NR2A, and NR2B) with a concentration-dependent property in comparison to controls. Additionally, the expression of memory kinases was attenuated statistically in the animals receiving the higher concentration, including protein kinase A (PKA), protein kinase C (PKC) and calcium/calmodulin-dependent protein kinaseIIα (CaMKIIα). And the inflammatory cytokine release was increased in rats exposed to SO2. Taken together, our results suggest that long-term exposure to SO2 air pollution at concentrations above the environmental standard in rats impaired spatial learning and memory, and indicate a close link between the neurobiological changes highlighted in the brain and the behavioral disturbances.
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Affiliation(s)
- Gaoyi Yao
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, PR China
| | - Huifeng Yue
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, PR China
| | - Yang Yun
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, PR China
| | - Nan Sang
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan, Shanxi 030006, PR China.
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24
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Li J, Bo L, Zhang P, Gao Q, Li L, Tang J, Wu C, Li D, Xiao J, Chen J, Tao J, Mao C, Xu Z. Exposure to nicotine during pregnancy and altered learning and memory in the rat offspring. Nicotine Tob Res 2014; 17:661-6. [PMID: 25239954 DOI: 10.1093/ntr/ntu178] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 08/20/2014] [Indexed: 11/14/2022]
Abstract
INTRODUCTION Prenatal exposure to nicotine can cause many fetal developmental problems. This study determined the influence of nicotine during pregnancy on the development of cognitive behavior in the offspring. METHODS Nicotine was administered to pregnant rats through implanted osmotic mini-pumps at 6mg/kg/day and flow rate of 60 μl/day for whole pregnancy from gestational day 4. Fetal and offspring body and brain weight was measured. Learning and memory were tested in adult offspring with Morris water maze; Learning and memory-related receptors were measured. RESULTS The results showed that exposure to prenatal nicotine (PN) not only caused fetal growth restriction, but also had long-term effects on learning and memory in the offspring. The PN offspring exhibited longer escape latency regardless of sex. The number of passing the platform was significantly less in the PN offspring than that of the control. The expression of messenger RNA (mRNA) and protein of N-methyl-D-aspartic acid receptor (NMDAR) in the hippocampus was significantly increased, whereas alpha7 nicotinic acetylcholine receptor (α7 nAChR) protein was decreased with unchanged α7 nAChR mRNA in the PN offspring. CONCLUSION The data provided novel information on the PN-affected development in learning and memory in the offspring, suggesting that α7 nAChR and NMDAR1 in the hippocampus might be the targets for actions of PN in association with memory impairment.
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Affiliation(s)
- Jiayue Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Le Bo
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Pengjie Zhang
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Qinqin Gao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Lingjun Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jiaqi Tang
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Chonglong Wu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Dawei Li
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jianping Xiao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jie Chen
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Jianying Tao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Caiping Mao
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China
| | - Zhice Xu
- Institute for Fetology, First Hospital of Soochow University, Suzhou, China; Center for Perinatal Biology, Loma Linda University, Loma Linda, CA
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25
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Abstract
Glutamate is the main excitatory neurotransmitter in the brain and ionotropic glutamate receptors mediate the majority of excitatory neurotransmission (Dingeldine et al. 1999). The high level of glutamatergic excitation allows the neonatal brain (the 2(nd) postnatal week in rat) to develop quickly but it also makes it highly prone to age-specific seizures that can cause lifelong neurological and cognitive disability (Haut et al. 2004). There are three types of ionotropic glutamate receptors (ligand-gated ion channels) named according to their prototypic agonists: N-methyl-D-aspartate (NMDA), 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propanoic acid (AMPA) and kainate (KA). During early stages of postnatal development glutamate receptors of NMDA and AMPA type undergo intensive functional changes owing to modifications in their subunit composition (Carter et al. 1988, Watanabe et al. 1992, Monyer et al. 1994, Wenzel et al. 1997, Sun et al. 1998, Lilliu et al. 2001, Kumar et al. 2002, Matsuda et al. 2002, Wee et al. 2008, Henson et al. 2010, Pachernegg et al. 2012, Paoletti et al. 2013). Participation and role of these receptors in mechanisms of seizures and epilepsy became one of the main targets of intensive investigation (De Sarro et al. 2005, Di Maio et al. 2012, Rektor 2013). LiCl/Pilocarpine (LiCl/Pilo) induced status epilepticus is a model of severe seizures resulting in development temporal lobe epilepsy (TLE). This review will consider developmental changes and contribution of NMDA and AMPA receptors in LiCl/Pilo model of status epilepticus in immature rats.
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Affiliation(s)
- E Szczurowska
- Institute of Physiology AS CR, Prague, Czech Republic.
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26
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Zhao C, Du CP, Peng Y, Xu Z, Sun CC, Liu Y, Hou XY. The upregulation of NR2A-containing N-methyl-D-aspartate receptor function by tyrosine phosphorylation of postsynaptic density 95 via facilitating Src/proline-rich tyrosine kinase 2 activation. Mol Neurobiol 2014; 51:500-11. [PMID: 24981431 DOI: 10.1007/s12035-014-8796-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 06/15/2014] [Indexed: 10/25/2022]
Abstract
The activation of postsynaptic N-methyl-D-aspartate (NMDA) receptors is required for long-term potentiation (LTP) of synaptic transmission. Postsynaptic density 95 (PSD-95) serves as a scaffold protein that tethers NMDA receptor subunits, kinases, and signal molecules. Our previous study proves that PSD-95 is a substrate of Src/Fyn and identifies Y523 on PSD-95 as a principal phosphorylation site. In this paper, we try to define an involvement and molecular consequences of PSD-95 phosphorylation by Src in NMDA receptor regulation. We found that either NMDA or chemical LTP induction leads to rapid phosphorylation of PSD-95 by Src in cultured cortical neurons. The phosphorylation of Y523 on PSD-95 potentiates NR2A-containing NMDA receptor current amplitude, implying an important role of Src-mediated PSD-95 phosphorylation in NMDA receptor activation. Comparing to wild-type PSD-95, overexpression of nonphosphorylatable mutant PSD-95Y523F attenuated the NMDA-stimulated NR2A tyrosine phosphorylation that enhances electrophysiological responses of NMDA receptor channels, while did not affect the membrane localization of NR2A subunits. PSD-95Y523D, a phosphomimetic mutant of PSD-95, induced NR2A tyrosine phosphorylation even if there was no NMDA treatment. In addition, the deficiency of Y523 phosphorylation on PSD-95 impaired the facilitatory effect of PSD-95 on the activation of Src and proline-rich tyrosine kinase 2 (Pyk2) and decreased the binding of Pyk2 with PSD-95. These results indicate that PSD-95 phosphorylation by Src facilitates the integration of Pyk2 to PSD-95 signal complex, the activation of Pyk2/Src, as well as the subsequent tyrosine phosphorylation of NR2A, which ultimately results in the upregulation of NMDA receptor function and synaptic transmission.
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Affiliation(s)
- Chao Zhao
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, 209 Tongshan Road, Xuzhou, Jiangsu, 221004, China
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27
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Cheng J, Liu W, Duffney LJ, Yan Z. SNARE proteins are essential in the potentiation of NMDA receptors by group II metabotropic glutamate receptors. J Physiol 2013; 591:3935-47. [PMID: 23774277 DOI: 10.1113/jphysiol.2013.255075] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The group II metabotropic glutamate receptors (group II mGluRs) have emerged as the new drug targets for the treatment of mental disorders like schizophrenia. To understand the potential mechanisms underlying the antipsychotic effects of group II mGluRs, we examined their impact on NMDA receptors (NMDARs), since NMDAR hypofunction has been implicated in schizophrenia. The activation of group II mGluRs caused a significant enhancement of NMDAR currents in cortical pyramidal neurons, which was associated with increased NMDAR surface expression and synaptic localization. We further examined whether these effects of group II mGluRs are through the regulation of NMDAR exocytosis via SNARE proteins, a family of proteins involved in vesicle fusion. We found that the enhancing effect of APDC, a selective agonist of group II mGluRs, on NMDAR currents was abolished when botulinum toxin was delivered into the recorded neurons to disrupt the SNARE complex. Inhibiting the function of two key SNARE proteins, SNAP-25 and syntaxin 4, also eliminated the effect of APDC on NMDAR currents. Moreover, the application of APDC increased the activity of Rab4, a small Rab GTPase mediating fast recycling from early endosomes to the plasma membrane, and enhanced the interaction between syntaxin 4 and Rab4. Knockdown of Rab4 or expression of dominant-negative Rab4 attenuated the effect of APDC on NMDAR currents. Taken together, these results have identified key molecules involved in the group II mGluR-induced potentiation of NMDAR exocytosis and function.
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Affiliation(s)
- Jia Cheng
- Department of Physiology and Biophysics, State University of New York at Buffalo, NY 14214, USA
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28
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Synaptic non-GluN2B-containing NMDA receptors regulate tyrosine phosphorylation of GluN2B 1472 tyrosine site in rat brain slices. Neurosci Bull 2013; 29:614-20. [PMID: 23585298 DOI: 10.1007/s12264-013-1337-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Accepted: 10/23/2012] [Indexed: 10/27/2022] Open
Abstract
Activation of N-methyl-D-aspartate receptors (NMDARs) mediates changes in the phosphorylation status of the glutamate receptors themselves. Previous studies have indicated that during synaptic activity, tyrosine kinases (Src and Fyn) or phosphatases (PTPα and STEP) are involved in regulating the phosphorylation of NMDARs. In this study, we used immunoblotting to investigate the role of an NMDAR subpopulation on the phosphorylation level of the GluN2B subunit at the Y1336 and Y1472 sites in rat brain slices after NMDA treatment. We found that NMDA stimulation dramatically decreased the phosphorylation level of GluN2B at Y1472 in a dose- and time-dependent manner, but not at Y1336. Extrasynaptic NMDAR activation did not reduce the phosphorylation of GluN2B at Y1472. In addition, ifenprodil, a selective antagonist of GluN2B-containing NMDARs, did not abolish the decreased phosphorylation of GluN2B at Y1472 triggered by NMDA. These results suggest that the activation of synaptic GluN2A-containing NMDARs is required for the decreased phosphorylation of GluN2B at Y1472 that is induced by NMDA treatment in rat brain slices.
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29
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Ferrario CR, Ndukwe BO, Ren J, Satin LS, Goforth PB. Stretch injury selectively enhances extrasynaptic, GluN2B-containing NMDA receptor function in cortical neurons. J Neurophysiol 2013; 110:131-40. [PMID: 23576693 DOI: 10.1152/jn.01011.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alterations in the function and expression of NMDA receptors are observed after in vivo and in vitro traumatic brain injury. We recently reported that mechanical stretch injury in cortical neurons transiently increases the contribution of NMDA receptors to network activity and results in an increase in calcium-permeable AMPA (CP-AMPA) receptor-mediated transmission 4 h postinjury (Goforth et al. 2011). Here, we evaluated changes in the function of synaptic vs. extrasynaptic GluN2B-containing NMDA receptors after injury. We also determined whether postinjury treatment with the GluN2B-selective antagonist Ro 25-6981 or memantine prevents injury-induced increases in CP-AMPA receptor activity. We found that injury increased extrasynaptic, GluN2B-containing NMDA receptor-mediated whole cell currents. In contrast, we found no differences in synaptic NMDA receptor-mediated transmission after injury. Furthermore, treatment with Ro 25-6981 or memantine after injury prevented injury-induced increases in CP-AMPA receptor-mediated activity. Together, our data suggest that increased NMDA receptor activity after injury is predominantly due to alterations in extrasynaptic, GluN2B-containing NMDA receptors and that activation of these receptors may contribute to the appearance of CP-AMPA receptors after injury.
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Affiliation(s)
- Carrie R Ferrario
- Department of Pharmacology, The University of Michigan, Ann Arbor, Michigan 48105, USA
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30
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Nair R, Lauks J, Jung S, Cooke NE, de Wit H, Brose N, Kilimann MW, Verhage M, Rhee J. Neurobeachin regulates neurotransmitter receptor trafficking to synapses. J Cell Biol 2013; 200:61-80. [PMID: 23277425 PMCID: PMC3542797 DOI: 10.1083/jcb.201207113] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 10/26/2012] [Indexed: 12/12/2022] Open
Abstract
The surface density of neurotransmitter receptors at synapses is a key determinant of synaptic efficacy. Synaptic receptor accumulation is regulated by the transport, postsynaptic anchoring, and turnover of receptors, involving multiple trafficking, sorting, motor, and scaffold proteins. We found that neurons lacking the BEACH (beige-Chediak/Higashi) domain protein Neurobeachin (Nbea) had strongly reduced synaptic responses caused by a reduction in surface levels of glutamate and GABA(A) receptors. In the absence of Nbea, immature AMPA receptors accumulated early in the biosynthetic pathway, and mature N-methyl-d-aspartate, kainate, and GABA(A) receptors did not reach the synapse, whereas maturation and surface expression of other membrane proteins, synapse formation, and presynaptic function were unaffected. These data show that Nbea regulates synaptic transmission under basal conditions by targeting neurotransmitter receptors to synapses.
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Affiliation(s)
- Ramya Nair
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Juliane Lauks
- Department of Functional Genomics and Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit and Vrije Universiteit Medical Center, 1081 HV Amsterdam, Netherlands
| | - SangYong Jung
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | - Nancy E. Cooke
- Department of Genetics and Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104
| | - Heidi de Wit
- Department of Functional Genomics and Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit and Vrije Universiteit Medical Center, 1081 HV Amsterdam, Netherlands
| | - Nils Brose
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
| | | | - Matthijs Verhage
- Department of Functional Genomics and Department of Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit and Vrije Universiteit Medical Center, 1081 HV Amsterdam, Netherlands
| | - JeongSeop Rhee
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, 37075 Göttingen, Germany
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31
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Henson MA, Larsen RS, Lawson SN, Pérez-Otaño I, Nakanishi N, Lipton SA, Philpot BD. Genetic deletion of NR3A accelerates glutamatergic synapse maturation. PLoS One 2012; 7:e42327. [PMID: 22870318 PMCID: PMC3411625 DOI: 10.1371/journal.pone.0042327] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 07/06/2012] [Indexed: 11/25/2022] Open
Abstract
Glutamatergic synapse maturation is critically dependent upon activation of NMDA-type glutamate receptors (NMDARs); however, the contributions of NR3A subunit-containing NMDARs to this process have only begun to be considered. Here we characterized the expression of NR3A in the developing mouse forebrain and examined the consequences of NR3A deletion on excitatory synapse maturation. We found that NR3A is expressed in many subcellular compartments, and during early development, NR3A subunits are particularly concentrated in the postsynaptic density (PSD). NR3A levels dramatically decline with age and are no longer enriched at PSDs in juveniles and adults. Genetic deletion of NR3A accelerates glutamatergic synaptic transmission, as measured by AMPAR-mediated postsynaptic currents recorded in hippocampal CA1. Consistent with the functional observations, we observed that the deletion of NR3A accelerated the expression of the glutamate receptor subunits NR1, NR2A, and GluR1 in the PSD in postnatal day (P) 8 mice. These data support the idea that glutamate receptors concentrate at synapses earlier in NR3A-knockout (NR3A-KO) mice. The precocious maturation of both AMPAR function and glutamate receptor expression are transient in NR3A-KO mice, as AMPAR currents and glutamate receptor protein levels are similar in NR3A-KO and wildtype mice by P16, an age when endogenous NR3A levels are normally declining. Taken together, our data support a model whereby NR3A negatively regulates the developmental stabilization of glutamate receptors involved in excitatory neurotransmission, synaptogenesis, and spine growth.
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Affiliation(s)
- Maile A Henson
- Curriculum in Neurobiology, University of North Carolina, Chapel Hill, North Carolina, United States of America.
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32
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Hodes GE, Brookshire BR, Hill-Smith TE, Teegarden SL, Berton O, Lucki I. Strain differences in the effects of chronic corticosterone exposure in the hippocampus. Neuroscience 2012; 222:269-80. [PMID: 22735575 DOI: 10.1016/j.neuroscience.2012.06.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 05/18/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022]
Abstract
Stress hormones are thought to be involved in the etiology of depression, in part, because animal models show they cause morphological damage to the brain, an effect that can be reversed by chronic antidepressant treatment. The current study examined two mouse strains selected for naturalistic variation of tissue regeneration after injury for resistance to the effects of chronic corticosterone (CORT) exposure on cell proliferation and neurotrophin mobilization. The wound healer MRL/MpJ and control C57BL/6J mice were implanted subcutaneously with pellets that released CORT for 7 days. MRL/MpJ mice were resistant to reductions of hippocampal cell proliferation by chronic exposure to CORT when compared to vulnerable C57BL/6J mice. Chronic CORT exposure also reduced protein levels of brain-derived neurotrophic factor (BDNF) in the hippocampus of C57BL/6J but not MRL/MpJ mice. CORT pellet exposure increased circulating levels of CORT in the plasma of both strains in a dose-dependent manner although MRL/MpJ mice may have larger changes from baseline. The strains did not differ in circulating levels of corticosterone binding globulin (CBG). There were also no strain differences in CORT levels in the hippocampus, nor did CORT exposure alter glucocorticoid receptor or mineralocorticoid receptor expression in a strain-dependent manner. Strain differences were found in the N-methyl-D-aspartate (NMDA) receptor, and BDNF I and IV promoters. Strain and CORT exposure interacted to alter tropomyosine-receptor-kinase B (TrkB) expression and this may be a potential mechanism protecting MRL/MpJ mice. In addition, differences in the inflammatory response of matrix metalloproteinases (MMPs) may also contribute to these strain differences in resistance to the deleterious effects of CORT to the brain.
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Affiliation(s)
- G E Hodes
- Department of Psychiatry, University of Pennsylvania, Philadelphia, PA 19104, United States
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Hei MY, Tao HK, Tang Q, Yu B, Zhao LL. Decreased levels of pNR1 S897 protein in the cortex of neonatal Sprague Dawley rats with hypoxic-ischemic or NMDA-induced brain damage. Braz J Med Biol Res 2012; 45:962-7. [PMID: 22714810 PMCID: PMC3854173 DOI: 10.1590/s0100-879x2012007500100] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 03/28/2012] [Indexed: 11/22/2022] Open
Abstract
Our objective was to investigate the protein level of phosphorylated N-methyl-D-aspartate (NMDA) receptor-1 at serine 897 (pNR1 S897) in both NMDA-induced brain damage and hypoxic-ischemic brain damage (HIBD), and to obtain further evidence that HIBD in the cortex is related to NMDA toxicity due to a change of the pNR1 S897 protein level. At postnatal day 7, male and female Sprague Dawley rats (13.12 ± 0.34 g) were randomly divided into normal control, phosphate-buffered saline (PBS) cerebral microinjection, HIBD, and NMDA cerebral microinjection groups. Immunofluorescence and Western blot (N = 10 rats per group) were used to examine the protein level of pNR1 S897. Immunofluorescence showed that control and PBS groups exhibited significant neuronal cytoplasmic staining for pNR1 S897 in the cortex. Both HIBD and NMDA-induced brain damage markedly decreased pNR1 S897 staining in the ipsilateral cortex, but not in the contralateral cortex. Western blot analysis showed that at 2 and 24 h after HIBD, the protein level of pNR1 S897 was not affected in the contralateral cortex (P > 0.05), whereas it was reduced in the ipsilateral cortex (P < 0.05). At 2 h after NMDA injection, the protein level of pNR1 S897 in the contralateral cortex was also not affected (P > 0.05). The levels in the ipsilateral cortex were decreased, but the change was not significant (P > 0.05). The similar reduction in the protein level of pNR1 S897 following both HIBD and NMDA-induced brain damage suggests that HIBD is to some extent related to NMDA toxicity possibly through NR1 phosphorylation of serine 897.
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Affiliation(s)
- Ming-Yan Hei
- Department of Pediatrics, The Third Xiangya Hospital, Central South University, Changsha, Hunan, China
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Jeans A, Malins R, Padamsey Z, Reinhart M, Emptage N. Increased expression of dysbindin-1A leads to a selective deficit in NMDA receptor signaling in the hippocampus. Neuropharmacology 2011; 61:1345-53. [PMID: 21856316 DOI: 10.1016/j.neuropharm.2011.08.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Revised: 07/21/2011] [Accepted: 08/05/2011] [Indexed: 12/18/2022]
Abstract
The effects of the major schizophrenia susceptibility gene disease DTNBP1 on disease risk are likely to be mediated through changes in expression level of the gene product, dysbindin-1. How such changes might influence pathogenesis is, however, unclear. One possible mechanism is suggested by recent work establishing a link between altered dysbindin-1 expression and changes in surface levels of N-methyl-d-aspartate receptors (NMDAR), although neither the precise nature of this relationship, nor the mechanism underlying it, are understood. Using organotypic slices of rat hippocampus, we show that increased expression of dysbindin-1A in pyramidal neurons causes a severe and selective hypofunction of NMDARs and blocks induction of LTP. Cell surface, but not cytoplasmic, expression of the NR1 subunit of the NMDAR is decreased, suggesting dysregulation of NMDAR trafficking and, consistent with this, pharmacological inhibition of clathrin-dependent endocytosis is sufficient to reverse the deficit in NMDAR signaling. These results support the idea that the level of the NMDAR at the plasma membrane is modulated by changes in dysbindin-1 expression and offer further insight into the role of dysbindin-1 at an important cellular pathway implicated in schizophrenia.
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Affiliation(s)
- Alexander Jeans
- Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
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Bard L, Groc L. Glutamate receptor dynamics and protein interaction: lessons from the NMDA receptor. Mol Cell Neurosci 2011; 48:298-307. [PMID: 21640188 DOI: 10.1016/j.mcn.2011.05.009] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Revised: 05/17/2011] [Accepted: 05/18/2011] [Indexed: 11/16/2022] Open
Abstract
The plasticity of excitatory glutamate synapses emerged over the last decades as a core cellular mechanism for the encoding and processing of various cognitive functions. This property relies in part on the ability to dynamically adjust the content of glutamate receptors in the postsynaptic membrane. Among these receptors, NMDA receptors (NMDAR), which are composed of two obligatory GluN1 and two regulatory GluN2/3 subunits, play a key role in the induction of many forms of plasticity processes. Understanding how NMDAR subtypes are trafficked and regulated in the synapse has thus captured considerable attention. It has emerged that NMDAR synaptic content relies on an equilibrium between intracellular trafficking and rapid lateral diffusion of the receptor within the synaptic area. Here, we review our current understanding of NMDAR trafficking, mostly the ones at the surface membrane, with a specific focus on the role of interacting PDZ-containing proteins during the journey of NMDAR to and around the synaptic area. The cellular and molecular lessons obtained from examining NMDAR dynamics and regulation by interacting proteins appear to apply to other ionotropic neurotransmitter receptors, and thus shed new light on the modulation of excitatory, inhibitory, and modulatory transmission. This article is part of a Special Issue entitled 'Neuronal Function'.
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Affiliation(s)
- Lucie Bard
- Univ. de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, F-33000 Bordeaux, France
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Abstract
Neuronal nitric oxide synthase (nNOS) is mainly expressed in neurons, to some extent in astrocytes and neuronal stem cells. The alternative splicing of nNOS mRNA generates 5 isoforms of nNOS, including nNOS-α, nNOS-β, nNOS-µ, nNOS-γ and nNOS-2. Monomer of nNOS is inactive, and dimer is the active form. Dimerization requires tetrahydrobiopterin (BH4), heme and L-arginine binding. Regulation of nNOS expression relies largely on cAMP response element-binding protein (CREB) activity, and nNOS activity is regulated by heat shock protein 90 (HSP90)/HSP70, calmodulin (CaM), phosphorylation and dephosphorylation at Ser847 and Ser1412, and the protein inhibitor of nNOS (PIN). There are primarily 9 nNOS-interacting proteins, including post-synaptic density protein 95 (PSD95), clathrin assembly lymphoid leukemia (CALM), calcium/calmodulin-dependent protein kinase II alpha (CAMKIIA), Disks large homolog 4 (DLG4), DLG2, 6-phosphofructokinase, muscle type (PFK-M), carboxy-terminal PDZ ligand of nNOS (CAPON) protein, syntrophin and dynein light chain (LC). Among them, PSD95, CAPON and PFK-M are important nNOS adapter proteins in neurons. The interaction of PSD95 with nNOS controls synapse formation and is implicated in N-methyl-D-aspartic acid-induced neuronal death. nNOS-derived NO is implicated in synapse loss-mediated early cognitive/motor deficits in several neuropathological states, and negatively regulates neurogenesis under physiological and pathological conditions.
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Ghafari M, Patil SS, Höger H, Pollak A, Lubec G. NMDA-complexes linked to spatial memory performance in the Barnes maze in CD1 mice. Behav Brain Res 2011; 221:142-8. [PMID: 21377497 DOI: 10.1016/j.bbr.2011.02.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 02/22/2011] [Accepted: 02/26/2011] [Indexed: 10/18/2022]
Abstract
The N-methyl-d-aspartic acid receptor (NMDAR) is a well-documented key element in the formation of several memories including spatial, olfactory and contextual memory. Although receptor subunits have been linked to memory formation, data on the involvement of the NMDAR complexes is limited. In previous work CD1 mice were trained in the Barnes maze, a low-stress landmaze, and yoked controls were serving as controls. Hippocampal samples from this behavioural study were taken for comparing NMDAR complexes. Hippocampi were taken and stored until analysis at -80 °C. Membrane proteins were extracted from hippocampi using an ultracentrifugation step and applied on Blue Native gels that in turn were used for immunoblotting with antibodies against subunits NR1, NR2A and NR2B. The subunit content of the complexes was determined by denaturing two-dimensional gel electrophoresis and subsequent immunoblotting. An NMDAR complex with an apparent molecular weight between between 146 and 242 kDa, probably representing an NR1 dimer was the only complex that was significantly different between trained and yoked animals. A series of NMDAR complexes containing modulatory subunits NR2A or NR2B or both were detected. All complexes contained the NR1 subunit. The NR1 dimer complex level, increased in memory formation, may be directly or indirectly involved in the process of spatial memory formation in the CD1 mouse. The results are enabling and challenging further NMDAR studies, both, at the pharmacological and molecular level. Moreover, several NMDAR complexes in the CD1 mouse were shown to be mainly heteropolymers of subunits NR1, NR2A and NR2B, although other recently described subunits were not tested due to unavailability of specific antibodies. Determination of native receptor complexes rather than individual subunits is mandatory and provides the molecular basis for understanding mechanisms of spatial memory.
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Affiliation(s)
- Maryam Ghafari
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria
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Tanaka S, Kondo H, Kanda K, Ashino T, Nakamachi T, Sekikawa K, Iwakura Y, Shioda S, Numazawa S, Yoshida T. Involvement of interleukin-1 in lipopolysaccaride-induced microglial activation and learning and memory deficits. J Neurosci Res 2011; 89:506-14. [PMID: 21290410 DOI: 10.1002/jnr.22582] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2010] [Revised: 09/16/2010] [Accepted: 11/11/2010] [Indexed: 11/11/2022]
Abstract
We have developed an animal model of learning and memory impairment associated with activation of microglia in the mouse brain. Injection of lipopolysaccharide into the CA1 region of the mouse hippocampus resulted in an increased production of inflammatory cytokines, such as interleukin-1β. Immunostaining for interleukin-1β revealed an increase in the signal at 6 hr after lipopolysaccharide injection. Immunopositive cells for interleukin-1β were colocalized with those immunopositive for CD11b. When subacute lipopolysaccharide treatment (20 μg/2 μl/injection, bilaterally for 5 consecutive days) was performed, long-term activation of microglia and learning and memory deficits as evaluated using a step-through passive avoidance test were observed in the wild-type mice. Gene expression of the N-methyl-D-aspartate receptor NR1 and NR2A subunits was also decreased by the lipopolysaccharide treatment. In contrast, activation of microglia and the associated behavioral deficits were not observed in mice lacking interleukin-1α and -1β following the subacute lipopolysaccharide treatment, together with little change in the gene expression of NR1 and NR2A subunits. However, the subacute lipopolysaccharide treatment produced almost similar changes in those parameters in the tumor necrosis factor-α knockout mice as in the wild-type animals. The injection of interleukin-1β neutralizing antibody with lipopolysaccharide for 5 consecutive days resulted in the improvement of lipopolysaccharide-induced learning and memory deficits. These findings suggest that the expression of interleukin-1 plays an important role in lipopolysaccharide-induced activation of microglia and the associated functional deficits in learning and memory.
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Affiliation(s)
- S Tanaka
- Department of Biochemical Toxicology, School of Pharmacy, Showa University, Tokyo, Japan.
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Zimmerman JM, Maren S. NMDA receptor antagonism in the basolateral but not central amygdala blocks the extinction of Pavlovian fear conditioning in rats. Eur J Neurosci 2010; 31:1664-70. [PMID: 20525079 DOI: 10.1111/j.1460-9568.2010.07223.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glutamate receptors in the basolateral complex of the amygdala (BLA) are essential for the acquisition, expression and extinction of Pavlovian fear conditioning in rats. Recent work has revealed that glutamate receptors in the central nucleus of the amygdala (CEA) are also involved in the acquisition of conditional fear, but it is not known whether they play a role in fear extinction. Here we examine this issue by infusing glutamate receptor antagonists into the BLA or CEA prior to the extinction of fear to an auditory conditioned stimulus (CS) in rats. Infusion of the alpha-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) receptor antagonist, 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo[f]quinoxaline-2,3-dione (NBQX), into either the CEA or BLA impaired the expression of conditioned freezing to the auditory CS, but did not impair the formation of a long-term extinction memory to that CS. In contrast, infusion of the N-methyl-D-aspartate (NMDA) receptor antagonist, D,L-2-amino-5-phosphonopentanoic acid (APV), into the amygdala, spared the expression of fear to the CS during extinction training, but impaired the acquisition of a long-term extinction memory. Importantly, only APV infusions into the BLA impaired extinction memory. These results reveal that AMPA and NMDA receptors within the amygdala make dissociable contributions to the expression and extinction of conditioned fear, respectively. Moreover, they indicate that NMDA receptor-dependent processes involved in extinction learning are localized to the BLA. Together with previous work, these results reveal that NMDA receptors in the CEA have a selective role acquisition of fear memory.
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Day DE, Cooper MA, Markham CM, Huhman KL. NR2B subunit of the NMDA receptor in the basolateral amygdala is necessary for the acquisition of conditioned defeat in Syrian hamsters. Behav Brain Res 2010; 217:55-9. [PMID: 20933543 DOI: 10.1016/j.bbr.2010.09.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2010] [Accepted: 09/30/2010] [Indexed: 11/18/2022]
Abstract
Reversible inactivation of the basolateral amygdala (BLA) disrupts the acquisition and expression of conditioned defeat (CD), an ethological model of conditioned fear, suggesting that the BLA may be a critical component of the neural circuit mediating behavioral plasticity associated with the experience of social defeat. We have also shown that this effect is N-methyl-d-aspartic acid (NMDA) receptor-dependent, because infusion of d,l-2-amino-5-phosphovalerate (APV) into the BLA also impairs the acquisition of CD. APV is a non-selective NMDA antagonist, however, thus it disrupts the entire heteromeric receptor complex, making it difficult to distinguish the relative contributions of either the NR2A or NR2B receptor subtypes on the acquisition of CD. There is ample evidence, however, that the NR2B subunit of the NMDA receptor in the amygdala is critical for mediating long-term potentiation and plasticity related to fear learning. The purpose of the present experiment was to determine whether infusion of ifenprodil, a selective antagonist of the NR2B subunit, into the BLA would block the acquisition (but not expression) of CD. In Experiment 1, infusion of ifenprodil immediately before defeat training significantly decreased submissive behaviors and restored territorial aggression when hamsters were later paired with a non-aggressive intruder (NAI). Conversely, infusion of ifenprodil immediately before CD testing failed to inhibit the expression of submissive behaviors in previously defeated hamsters. These results support the hypothesis that the BLA is a critical site for the plasticity underlying social defeat-induced changes in behavior.
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Affiliation(s)
- Diane E Day
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA
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Hori N, Kadota MT, Watanabe M, Ito Y, Akaike N, Carpenter DO. Neurotoxic effects of methamphetamine on rat hippocampus pyramidal neurons. Cell Mol Neurobiol 2010; 30:849-56. [PMID: 20232135 DOI: 10.1007/s10571-010-9512-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 03/02/2010] [Indexed: 11/24/2022]
Abstract
Methamphetamine (MAP) is known to alter behavior and cause deficits in learning and memory. While the major site of action of MAP is on mesolimbic dopaminergic pathways, the effects on learning and memory raise the possibility of important actions in the hippocampus. We have studied electrophysiologic and morphologic effects of MAP in the CA1 region of hippocampus from young male rats chronically exposed to MAP, male rats exposed during gestation only and the effects of bath perfusion of MAP onto brain slices from control rats. Pyramidal neurons in brain slices from chronically exposed rats had reduced membrane potential and membrane resistance. Long-term potentiation (LTP) was reduced as compared to control, but when MAP was acutely perfused over control slices the amplitude of LTP was increased. LTP in young adult animals that had been gestationally exposed to MAP showed reduced LTP as compared to controls. Morphologically CA1 pyramidal neurons in chronically exposed animals showed a high prevalence of extensive blebbing of dendrites. We conclude that the NMDA receptor and the process of LTP are also targets of MAP dysfunction, at least in the hippocampus.
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Affiliation(s)
- N Hori
- Division of Life Science, University of Texas at San Antonio, 6900 North Loop 1604, West San Antonio, TX 78249-066, USA
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Vazhappilly R, Wee KSL, Sucher NJ, Low CM. A non-muscle myosin II motor links NR1 to retrograde trafficking and proteasomal degradation in PC12 cells. Neurochem Int 2010; 56:569-76. [PMID: 20064569 DOI: 10.1016/j.neuint.2009.12.020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 12/24/2009] [Accepted: 12/31/2009] [Indexed: 10/20/2022]
Abstract
Rat pheochromocytoma (PC12) cells have been shown to lack functional NMDA receptors; yet, these cells express NR1 subunits of the NMDA receptor. The reason for the lack of functional receptors has been attributed to the absence of significant levels of NR2 subunits to co-assemble with NR1. It is known that PC12 expresses very low levels of NR2C, with complete absence of other types of NR2 subunits. The purpose of the present study is to describe the molecular mechanism of trafficking and degradation of unassembled NR1 subunits in PC12 cells. The localization of NR1 subunits in PC12 cells were evaluated by immunofluorescence and co-immunoprecipitation, which showed that NR1 was present in the endoplasmic reticulum and cis-middle compartments of the Golgi apparatus. Upon treatment with a proteasome inhibitor, MG132, the ubiquitinylated species of NR1 subunit were detected, suggesting that NR1 is being targeted for endoplasmic reticulum-associated proteasomal degradation. Our previous studies suggest that NR1 subunits from the Golgi do not proceed to trans-Golgi, hence they will require re-routing to the endoplasmic reticulum for degradation. Further investigations on the factors involved in the trafficking of NR1 from Golgi to endoplasmic reticulum were performed using co-immunoprecipitation and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. These revealed the co-association of NR1 with non-muscle myosin heavy chain II isoforms A and B. We also demonstrate the functional significance of this interaction through the use of a myosin inhibitor, blebbistatin, to disrupt brefeldin A-induced Golgi-to-endoplasmic reticulum trafficking of NR1. In conclusion, our results suggest that non-muscle myosin II is involved in the retrograde trafficking of NR1 subunits from the cis/middle-Golgi to the endoplasmic reticulum for proteasomal degradation in PC12.
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Affiliation(s)
- Rema Vazhappilly
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Republic of Singapore
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Interaction of postsynaptic density protein-95 with NMDA receptors influences excitotoxicity in the yeast artificial chromosome mouse model of Huntington's disease. J Neurosci 2009; 29:10928-38. [PMID: 19726651 DOI: 10.1523/jneurosci.2491-09.2009] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Evidence suggests that NMDA-type glutamate receptors contribute to degeneration of striatal medium-sized spiny neurons (MSNs) in Huntington's disease (HD). Previously, we demonstrated that NMDA receptor (NMDAR)-mediated current and/or toxicity is increased in MSNs from the yeast artificial chromosome (YAC) transgenic mouse model expressing polyglutamine (polyQ)-expanded (mutant) full-length human huntingtin (htt). Others have shown that membrane-associated guanylate kinases (MAGUKs), such as PSD-95 and SAP102, modulate NMDAR surface expression and excitotoxicity in hippocampal and cortical neurons and that htt interacts with PSD-95. Here, we tested the hypothesis that an altered association between MAGUKs and NMDARs in mutant huntingtin-expressing cells contributes to increased susceptibility to excitotoxicity. We show that htt coimmunoprecipitated with SAP102 in HEK293T cells and striatal tissue from wild-type and YAC transgenic mice; however, the association of SAP102 with htt or the NMDAR NR2B subunit was unaffected by htt polyQ length, whereas association of PSD-95 with NR2B in striatal tissue was enhanced by increased htt polyQ length. Treatment of cultured MSNs with Tat-NR2B9c peptide blocked binding of NR2B with SAP102 and PSD-95 and reduced NMDAR surface expression by 20% in both YAC transgenic and wild-type MSNs, and also restored susceptibility to NMDAR excitoxicity in YAC HD MSNs to levels observed in wild-type MSNs; a similar effect on excitotoxicity was observed after knockdown of PSD-95 by small interfering RNA. Unlike previous findings in cortical and hippocampal neurons, rescue of NMDA toxicity by Tat-NR2B9c occurred independently of any effect on neuronal nitric oxide synthase activity. Our results elucidate further the mechanisms underlying enhanced excitotoxicity in HD.
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Reduced spatial learning in mice treated with NVP-AAM077 through down-regulating neurogenesis. Eur J Pharmacol 2009; 622:37-44. [PMID: 19765576 DOI: 10.1016/j.ejphar.2009.09.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 09/01/2009] [Accepted: 09/10/2009] [Indexed: 01/17/2023]
Abstract
NR2A-containing N-methyl-D-aspartate (NMDA) receptors have important roles in influencing the long-term potentiation and spatial memory. Here using Morris water maze, we found that inhibition of NR2A-containing NMDA receptors by [(R)-[(S)-1-(4-bromophenyl)-ethylamino]-(2, 3-dioxo-1,2,3,4-tetrahydroquinoxalin-5-yl)-methyl]-phosphonic acid (NVP-AAM077) hindered the formation of spatial memory. An increasing number of reports suggest that adult hippocampal neurogenesis is involved in hippocampal-mediated learning. To explore the possible mechanisms understanding the reduced spatial memory by NVP-AAM077, we investigated the effects of NVP-AAM077 on neurogenesis. We found that NVP-AAM077 inhibited progenitor cells proliferation in the subventricular zone and dentate gyrus and reduced the survival of newborn cells in the dentate gyrus in the adult mice. In null mutant mice lacking neuronal nitric oxide synthase (nNOS) gene (nNOS(-/-)), the effects of NVP-AAM077 on neurogenesis disappeared. In addition, NVP-AAM077 increased nNOS enzymatic activity. Our findings suggest that NVP-AAM077 reduced spatial learning through down-regulating neurogenesis in the adult hippocampus.
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Lai KO, Ip NY. Recent advances in understanding the roles of Cdk5 in synaptic plasticity. Biochim Biophys Acta Mol Basis Dis 2009; 1792:741-5. [DOI: 10.1016/j.bbadis.2009.05.001] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2008] [Revised: 05/03/2009] [Accepted: 05/05/2009] [Indexed: 01/05/2023]
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Ng D, Pitcher GM, Szilard RK, Sertié A, Kanisek M, Clapcote SJ, Lipina T, Kalia LV, Joo D, McKerlie C, Cortez M, Roder JC, Salter MW, McInnes RR. Neto1 is a novel CUB-domain NMDA receptor-interacting protein required for synaptic plasticity and learning. PLoS Biol 2009; 7:e41. [PMID: 19243221 PMCID: PMC2652390 DOI: 10.1371/journal.pbio.1000041] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Accepted: 01/12/2009] [Indexed: 01/22/2023] Open
Abstract
The N-methyl-D-aspartate receptor (NMDAR), a major excitatory ligand-gated ion channel in the central nervous system (CNS), is a principal mediator of synaptic plasticity. Here we report that neuropilin tolloid-like 1 (Neto1), a complement C1r/C1s, Uegf, Bmp1 (CUB) domain-containing transmembrane protein, is a novel component of the NMDAR complex critical for maintaining the abundance of NR2A-containing NMDARs in the postsynaptic density. Neto1-null mice have depressed long-term potentiation (LTP) at Schaffer collateral-CA1 synapses, with the subunit dependency of LTP induction switching from the normal predominance of NR2A- to NR2B-NMDARs. NMDAR-dependent spatial learning and memory is depressed in Neto1-null mice, indicating that Neto1 regulates NMDA receptor-dependent synaptic plasticity and cognition. Remarkably, we also found that the deficits in LTP, learning, and memory in Neto1-null mice were rescued by the ampakine CX546 at doses without effect in wild-type. Together, our results establish the principle that auxiliary proteins are required for the normal abundance of NMDAR subunits at synapses, and demonstrate that an inherited learning defect can be rescued pharmacologically, a finding with therapeutic implications for humans. The fundamental unit for information processing in the brain is the synapse, a highly specialized site of communication between the brain's multitude of individual neurons. The strength of the communication at each synapse changes in response to neuronal activity—a process called synaptic plasticity—allowing networks of neurons to adapt and learn. How synaptic plasticity occurs is a major question in neurobiology. A central player in synaptic plasticity is an assembly of synaptic proteins called the NMDA receptor complex. Here, we discovered that the protein Neto1 is a component of the NMDA receptor complex. Neto1-deficient mice had a dramatic decrease in the number of NMDA receptors at synapses and consequently, synaptic plasticity and learning were impaired. By indirectly enhancing the function of the residual NMDA receptors in Neto1-deficient mice with a small molecule, we restored synaptic plasticity and learning to normal levels. Our findings establish the principle that inherited abnormalities of synaptic plasticity and learning due to NMDA receptor dysfunction can be pharmacologically corrected. Our discoveries also suggest that synaptic proteins that share a molecular signature, called the CUB domain, with Neto1 may be important components of synaptic receptors across species, because several CUB-domain proteins in worms have also been found to regulate synaptic receptors. Spatial learning and memory depend on the N-methyl-D-aspartic acid receptor, a synaptic ion channel regulated by Neto1. Impaired cognition due to the absence of Neto1 can be rescued pharmacologically, a finding with implications for the therapy of inherited learning defects in humans.
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Affiliation(s)
- David Ng
- Program in Developmental Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Genetics & Genome Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Graham M Pitcher
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Rachel K Szilard
- Program in Developmental Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Genetics & Genome Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andréa Sertié
- Program in Developmental Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Genetics & Genome Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Marijana Kanisek
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital Research Institute, Toronto, Ontario, Canada
| | | | - Tatiana Lipina
- Mount Sinai Hospital Research Institute, Toronto, Ontario, Canada
| | - Lorraine V Kalia
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Daisy Joo
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Colin McKerlie
- Department of Laboratory Medicine & Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Miguel Cortez
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
| | - John C Roder
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Mount Sinai Hospital Research Institute, Toronto, Ontario, Canada
| | - Michael W Salter
- Neurosciences & Mental Health, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- * To whom correspondence should be addressed. E-mail: (MWS); (RRM)
| | - Roderick R McInnes
- Program in Developmental Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Program in Genetics & Genome Biology, The Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
- Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada
- * To whom correspondence should be addressed. E-mail: (MWS); (RRM)
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Decreased NR2B subunit synaptic levels cause impaired long-term potentiation but not long-term depression. J Neurosci 2009; 29:669-77. [PMID: 19158293 DOI: 10.1523/jneurosci.3921-08.2009] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The discovery of the molecular mechanisms regulating the abundance of synaptic NMDA receptors is essential for understanding how synaptic plasticity, as well as excitotoxic events, are regulated. However, a complete understanding of the precise molecular mechanisms regulating the composition of the NMDA receptor complex at hippocampal synapse is still missing. Here, we show that 2 h of CaMKII inhibition leads to a specific reduction of synaptic NR2B-containing NMDA receptors without affecting localization of the NR2A subunit; this molecular event is accompanied by a dramatic reduction in the induction of long-term potentiation (LTP), while long-term depression induction is unaffected. The same molecular and functional results were obtained by disrupting NR2B/PSD-95 complex with NR2B C-tail cell permeable peptide (TAT-2B). These data indicate that NR2B redistribution between synaptic and extrasynaptic membranes represents an important molecular disturbance of the glutamatergic synapse and affects the correct induction of LTP.
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48
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Hoe HS, Fu Z, Makarova A, Lee JY, Lu C, Feng L, Pajoohesh-Ganji A, Matsuoka Y, Hyman BT, Ehlers MD, Vicini S, Pak DTS, Rebeck GW. The effects of amyloid precursor protein on postsynaptic composition and activity. J Biol Chem 2009; 284:8495-506. [PMID: 19164281 PMCID: PMC2659208 DOI: 10.1074/jbc.m900141200] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Indexed: 11/06/2022] Open
Abstract
The amyloid precursor protein (APP) is cleaved to produce the Alzheimer disease-associated peptide Abeta, but the normal functions of uncleaved APP in the brain are unknown. We found that APP was present in the postsynaptic density of central excitatory synapses and coimmunoprecipitated with N-methyl-d-aspartate receptors (NMDARs). The presence of APP in the postsynaptic density was supported by the observation that NMDARs regulated trafficking and processing of APP; overexpression of the NR1 subunit increased surface levels of APP, whereas activation of NMDARs decreased surface APP and promoted production of Abeta. We transfected APP or APP RNA interference into primary neurons and used electrophysiological techniques to explore the effects of APP on postsynaptic function. Reduction of APP decreased (and overexpression of APP increased) NMDAR whole cell current density and peak amplitude of spontaneous miniature excitatory postsynaptic currents. The increase in NMDAR current by APP was due to specific recruitment of additional NR2B-containing receptors. Consistent with these findings, immunohistochemical experiments demonstrated that APP increased the surface levels and decreased internalization of NR2B subunits. These results demonstrate a novel physiological role of postsynaptic APP in enhancing NMDAR function.
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Affiliation(s)
- Hyang-Sook Hoe
- Departments of Neuroscience, Physiology and Biophysics, Pharmacology, and Neurology, Georgetown University Medical Center, Washington, D. C. 20057-1464, USA
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49
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Lai SK, Lai CH, Tse YC, Yung KKL, Shum DKY, Chan YS. Developmental maturation of ionotropic glutamate receptor subunits in rat vestibular nuclear neurons responsive to vertical linear acceleration. Eur J Neurosci 2009; 28:2157-72. [PMID: 19046363 DOI: 10.1111/j.1460-9568.2008.06523.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the maturation profile of subunits of ionotropic glutamate receptors in vestibular nuclear neurons that were activated by sinusoidal linear acceleration along the vertical plane. The otolithic origin of Fos expression in these neurons was confirmed as a marker of functional activation when labyrinthectomized and/or stationary control rats contrasted by showing sporadically scattered Fos-labeled neurons in the vestibular nuclei. By double immunohistochemistry for Fos and one of the receptor subunits, otolith-related neurons that expressed either alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionate or N-methyl-d-aspartate subunits were first identified in the medial vestibular nucleus, spinal vestibular nucleus and Group x by postnatal day (P)7, and in the lateral vestibular nucleus and Group y by P9. No double-labeled neurons were found in the superior vestibular nucleus. Within each vestibular subnucleus, these double-labeled neurons constituted approximately 90% of the total Fos-labeled neurons. The percentage of Fos-labeled neurons expressing the GluR1 or NR2A subunit showed developmental invariance in all subnuclei. For Fos-labeled neurons expressing the NR1 subunit, similar invariance was observed except that, in Group y, these neurons decreased from P14 onwards. For Fos-labeled neurons expressing the GluR2, GluR2/3, GluR4 or NR2B subunit, a significant decrease was found by the adult stage. In particular, those expressing the GluR4 subunit showed a two- to threefold decrease in the medial vestibular nucleus, spinal vestibular nucleus and Group y. Also, those expressing the NR2B subunit showed a twofold decrease in Group y. Taken together, the postsynaptic expression of ionotropic glutamate receptor subunits in different vestibular subnuclei suggests that glutamatergic transmission within subregions plays differential developmental roles in the coding of gravity-related vertical spatial information.
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Affiliation(s)
- Suk-King Lai
- Department of Physiology, LKS Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Hong Kong, China
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50
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Increased tyrosine phosphorylation of PSD-95 by Src family kinases after brain ischaemia. Biochem J 2009; 417:277-85. [PMID: 18721130 DOI: 10.1042/bj20080004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PSD (postsynaptic density)-95, a scaffold protein that tethers NMDA (N-methyl-D-aspartate) receptors to signal molecules, is implicated in pathological events resulting from excitotoxicity. The present study demonstrates that brain ischaemia and reperfusion increase the tyrosine phosphorylation of PSD-95 in the rat hippocampus. PP2, a specific inhibitor of SrcPTKs (Src family protein tyrosine kinases), prevents the ischaemia-induced increases not only in the tyrosine phosphorylation of PSD-95, but also in the interaction between PSD-95 and Src kinases. PSD-95 is phosphorylated either by purified Src/Fyn kinases in vitro or by co-expression of constitutively active Src/Fyn in COS7 cells. The results suggest that SrcPTKs are involved in PSD-95 phosphorylation. The single Tyr(523) mutation to phenylalanine (Y523F) reduces the Src/Fyn-mediated phosphorylation of PSD-95 in COS7 cells and in vitro. As shown with a rabbit polyclonal antibody against phospho-PSD-95 (Tyr(523)), Tyr(523) phosphorylation is responsible for the increased tyrosine phosphorylation of PSD-95 induced by ischaemia in the rat hippocampus. In cultured hippocampal neurons, overexpression of PSD-95 Y523F, but not PSD-95 Y533F, abolishes the facilitating effect of PSD-95 on the glutamate- or NMDA-mediated currents, implying that PSD-95 Tyr(523) phosphorylation contributes to the post-ischaemic over-activation of NMDA receptors. Thus the present study reveals an additional mechanism for the regulation of PSD-95 by tyrosine phosphorylation. This mechanism may be of pathological significance since it is associated with excitotoxicity in the ischaemic brain.
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