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Ehsanifar M, Jafari AJ, Nikzad H, Zavareh MS, Atlasi MA, Mohammadi H, Tameh AA. Prenatal exposure to diesel exhaust particles causes anxiety, spatial memory disorders with alters expression of hippocampal pro-inflammatory cytokines and NMDA receptor subunits in adult male mice offspring. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 176:34-41. [PMID: 30921694 DOI: 10.1016/j.ecoenv.2019.03.090] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 02/23/2019] [Accepted: 03/20/2019] [Indexed: 05/25/2023]
Abstract
Air pollution by Diesel exhaust (DE) consists of gaseous compounds and diesel exhaust particles (DEPs). Previous studies show associations between prenatal exposure to diesel exhaust affects the central nervous system (CNS). However, there was not reported that these effects were caused by gaseous compounds, diesel exhaust particles, or both. A limited number of studies in rodent models have shown that exposure to DEPs can result in CNS. Here, we explored the effects of prenatal exposure to DEPs on anxiety and learning and memory in NMRI mice male offspring. Three groups of pregnant mice were exposed to 350-400 μg DEPs/m3 for 2, 4 and 6 h daily in a closed system room. We examined anxiety and learning and memory in 8-to-9-week-old male offspring using the Elevated plus maze and Morris water maze (MWM) test. Hippocampi were isolated after the behavioral tests and measured pro-inflammatory cytokines and N-methyl-D-aspartate (NMDA) receptor expression by quantitative RT-PCR analysis. Mice exposed to DEPs in utero showed deficits in the Elevated plus maze and Morris water maze test. In addition, DEPs exposed mice exhibited decreased hippocampal NR2A and NR3B expression. Taken together, our data suggest that maternal DEP exposure is associated with anxiety, disrupts learning and memory and reduction hippocampal NR2A and NR3B expression in male offspring.
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Affiliation(s)
- Mojtaba Ehsanifar
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran; Research Center for Environmental Health Technology and Department of Environmental Health Engineering, School of Public Health Iran University of Medical Sciences, Tehran, Iran.
| | - Ahmad Jonidi Jafari
- Research Center for Environmental Health Technology and Department of Environmental Health Engineering, School of Public Health Iran University of Medical Sciences, Tehran, Iran
| | - Hossein Nikzad
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | | | - Mohammad Ali Atlasi
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran
| | - Hamed Mohammadi
- Department of Environmental Health Engineering, School of Public Health, Zanjan University of Medical Sciences, Zanjan, Iran
| | - Abolfazl Azami Tameh
- Anatomical Sciences Research Center, Kashan University of Medical Sciences, Kashan, Iran
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Soto D, Olivella M, Grau C, Armstrong J, Alcon C, Gasull X, Santos-Gómez A, Locubiche S, Gómez de Salazar M, García-Díaz R, Gratacòs-Batlle E, Ramos-Vicente D, Chu-Van E, Colsch B, Fernández-Dueñas V, Ciruela F, Bayés À, Sindreu C, López-Sala A, García-Cazorla À, Altafaj X. l-Serine dietary supplementation is associated with clinical improvement of loss-of-function GRIN2B-related pediatric encephalopathy. Sci Signal 2019; 12:12/586/eaaw0936. [DOI: 10.1126/scisignal.aaw0936] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Autosomal dominant mutations in GRIN2B are associated with severe encephalopathy, but little is known about the pathophysiological outcomes and any potential therapeutic interventions. Genetic studies have described the association between de novo mutations of genes encoding the subunits of the N-methyl-d-aspartate receptor (NMDAR) and severe neurological conditions. Here, we evaluated a missense mutation in GRIN2B, causing a proline-to-threonine switch (P553T) in the GluN2B subunit of NMDAR, which was found in a 5-year-old patient with Rett-like syndrome with severe encephalopathy. Structural molecular modeling predicted a reduced pore size of the mutant GluN2B-containing NMDARs. Electrophysiological recordings in a HEK-293T cell line expressing the mutated subunit confirmed this prediction and showed an associated reduced glutamate affinity. Moreover, GluN2B(P553T)-expressing primary murine hippocampal neurons showed decreased spine density, concomitant with reduced NMDA-evoked currents and impaired NMDAR-dependent insertion of the AMPA receptor subunit GluA1 at stimulated synapses. Furthermore, the naturally occurring coagonist d-serine restored function to GluN2B(P553T)-containing NMDARs. l-Serine dietary supplementation of the patient was hence initiated, resulting in the increased abundance of d-serine in the plasma and brain. The patient has shown notable improvements in motor and cognitive performance and communication after 11 and 17 months of l-serine dietary supplementation. Our data suggest that l-serine supplementation might ameliorate GRIN2B-related severe encephalopathy and other neurological conditions caused by glutamatergic signaling deficiency.
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Protein Kinase C Lambda Mediates Acid-Sensing Ion Channel 1a-Dependent Cortical Synaptic Plasticity and Pain Hypersensitivity. J Neurosci 2019; 39:5773-5793. [PMID: 31101759 DOI: 10.1523/jneurosci.0213-19.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/12/2019] [Accepted: 05/14/2019] [Indexed: 02/08/2023] Open
Abstract
Chronic pain is a serious debilitating disease for which effective treatment is still lacking. Acid-sensing ion channel 1a (ASIC1a) has been implicated in nociceptive processing at both peripheral and spinal neurons. However, whether ASIC1a also contributes to pain perception at the supraspinal level remains elusive. Here, we report that ASIC1a in ACC is required for thermal and mechanical hypersensitivity associated with chronic pain. ACC-specific genetic deletion or pharmacological blockade of ASIC1a reduced the probability of cortical LTP induction and attenuated inflammatory thermal hyperalgesia and mechanical allodynia in male mice. Using cell type-specific manipulations, we demonstrate that ASIC1a in excitatory neurons of ACC is a major player in cortical LTP and pain behavior. Mechanistically, we show that ASIC1a tuned pain-related cortical plasticity through protein kinase C λ-mediated increase of membrane trafficking of AMPAR subunit GluA1 in ACC. Importantly, postapplication of ASIC1a inhibitors in ACC reversed previously established nociceptive hypersensitivity in both chronic inflammatory pain and neuropathic pain models. These results suggest that ASIC1a critically contributes to a higher level of pain processing through synaptic potentiation in ACC, which may serve as a promising analgesic target for treatment of chronic pain.SIGNIFICANCE STATEMENT Chronic pain is a debilitating disease that still lacks effective therapy. Ion channels are good candidates for developing new analgesics. Here, we provide several lines of evidence to support an important role of cortically located ASIC1a channel in pain hypersensitivity through promoting long-term synaptic potentiation in the ACC. Our results indicate a promising translational potential of targeting ASIC1a to treat chronic pain.
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54
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CAMK2-Dependent Signaling in Neurons Is Essential for Survival. J Neurosci 2019; 39:5424-5439. [PMID: 31064859 DOI: 10.1523/jneurosci.1341-18.2019] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 03/29/2019] [Accepted: 03/29/2019] [Indexed: 01/09/2023] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CAMK2) is a key player in synaptic plasticity and memory formation. Mutations in Camk2a or Camk2b cause intellectual disability in humans, and severe plasticity and learning deficits in mice, indicating unique functions for each isoform. However, considering the high homology between CAMK2A and CAMK2B, it is conceivable that for critical functions, one isoform compensates for the absence of the other, and that the full functional spectrum of neuronal CAMK2 remains to be revealed.Here we show that germline as well as adult deletion of both CAMK2 isoforms in male or female mice is lethal. Moreover, Ca2+-dependent activity as well as autonomous activity of CAMK2 is essential for survival. Loss of both CAMK2 isoforms abolished LTP, whereas synaptic transmission remained intact. The double-mutants showed no gross morphological changes of the brain, and in contrast to the long-considered role for CAMK2 in the structural organization of the postsynaptic density (PSD), deletion of both CAMK2 isoforms did not affect the biochemical composition of the PSD. Together, these results reveal an essential role for CAMK2 signaling in early postnatal development as well as the mature brain, and indicate that the full spectrum of CAMK2 requirements cannot be revealed in the single mutants because of partial overlapping functions of CAMK2A and CAMK2B.SIGNIFICANCE STATEMENT CAMK2A and CAMK2B have been studied for over 30 years for their role in neuronal functioning. However, most studies were performed using single knock-out mice. Because the two isoforms show high homology with respect to structure and function, it is likely that some redundancy exists between the two isoforms, meaning that for critical functions CAMK2B compensates for the absence of CAMK2A and vice versa, leaving these functions to uncover. In this study, we generated Camk2a/Camk2b double-mutant mice, and observed that loss of CAMK2, as well as the loss of Ca2+-dependent and Ca2+-independent activity of CAMK2 is lethal. These results indicate that despite 30 years of research the full spectrum of CAMK2 functioning in neurons remains to be unraveled.
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Qiu B, Xu Y, Wang J, Liu M, Dou L, Deng R, Wang C, Williams KE, Stewart RB, Xie Z, Ren W, Zhao Z, Shou W, Liang T, Yong W. Loss of FKBP5 Affects Neuron Synaptic Plasticity: An Electrophysiology Insight. Neuroscience 2019; 402:23-36. [DOI: 10.1016/j.neuroscience.2019.01.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 01/07/2019] [Accepted: 01/11/2019] [Indexed: 11/26/2022]
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Kenton JA, Castillo R, Holmes A, Brigman JL. Cortico-hippocampal GluN2B is essential for efficient visual-spatial discrimination learning in a touchscreen paradigm. Neurobiol Learn Mem 2018; 156:60-67. [PMID: 30394331 DOI: 10.1016/j.nlm.2018.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 09/13/2018] [Accepted: 10/26/2018] [Indexed: 12/24/2022]
Abstract
Discrimination of similar spatial locations, an important feature of episodic memory, has traditionally been measured via delayed nonmatching-to-location tasks. Recently, we and others have demonstrated that touchscreen-based Trial Unique Nonmatching-to-Location (TUNL) tasks are sensitive to lesions of the dorsal hippocampus in the mouse. Previously we have shown that loss of the GluN2B subunit of the N-methyl-D-aspartate (NMDA) receptor in the dorsal CA1 and throughout the cortex impairs hippocampal-dependent water maze and fear conditioning paradigms. We investigated whether loss of GluN2B would alter performance of visual-spatial discrimination learning in a delay- or separation-dependent manner. GluN2B null mutants displayed initial impairments in accuracy on the easiest training variant of TUNL that were overcome with training. Loss of GluN2B also impaired performance on a problem series where delay and separation were systematically varied. We also observed a training-dependent effect on performance. Mutant mice that received extensive training performed similar to control mice when challenged on a variable delay and variable separation problem, while those that received minimal training were impaired across all delays and separations. Together, these data demonstrate that GluN2B in the dorsal CA1 and cortex are essential for efficient visual-spatial discrimination learning on the TUNL task. Further, training effects on performance in mutant mice suggest that alterations in synaptic plasticity after GluN2B loss may underlie intra- versus inter-session learning.
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Affiliation(s)
- Johnny A Kenton
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Rebecca Castillo
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, NM 87131, USA.
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Kellermayer B, Ferreira JS, Dupuis J, Levet F, Grillo-Bosch D, Bard L, Linarès-Loyez J, Bouchet D, Choquet D, Rusakov DA, Bon P, Sibarita JB, Cognet L, Sainlos M, Carvalho AL, Groc L. Differential Nanoscale Topography and Functional Role of GluN2-NMDA Receptor Subtypes at Glutamatergic Synapses. Neuron 2018; 100:106-119.e7. [PMID: 30269991 DOI: 10.1016/j.neuron.2018.09.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 04/26/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
NMDA receptors (NMDARs) play key roles in the use-dependent adaptation of glutamatergic synapses underpinning memory formation. In the forebrain, these plastic processes involve the varied contributions of GluN2A- and GluN2B-containing NMDARs that have different signaling properties. Although the molecular machinery of synaptic NMDAR trafficking has been under scrutiny, the postsynaptic spatial organization of these two receptor subtypes has remained elusive. Here, we used super-resolution imaging of NMDARs in rat hippocampal synapses to unveil the nanoscale topography of native GluN2A- and GluN2B-NMDARs. Both subtypes were found to be organized in separate nanodomains that vary over the course of development. Furthermore, GluN2A- and GluN2B-NMDAR nanoscale organizations relied on distinct regulatory mechanisms. Strikingly, the selective rearrangement of GluN2A- and GluN2B-NMDARs, with no overall change in NMDAR current amplitude, allowed bi-directional tuning of synaptic LTP. Thus, GluN2A- and GluN2B-NMDAR nanoscale organizations are differentially regulated and seem to involve distinct signaling complexes during synaptic adaptation.
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Affiliation(s)
- Blanka Kellermayer
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal.
| | - Joana S Ferreira
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Julien Dupuis
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Florian Levet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNRS, Bordeaux Imaging Center UMS 3420, 33000 Bordeaux, France
| | - Dolors Grillo-Bosch
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Lucie Bard
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; UCL Institute of Neurology, University College London, London, UK
| | - Jeanne Linarès-Loyez
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Delphine Bouchet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Daniel Choquet
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France; CNRS, Bordeaux Imaging Center UMS 3420, 33000 Bordeaux, France
| | - Dmitri A Rusakov
- UCL Institute of Neurology, University College London, London, UK
| | - Pierre Bon
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Jean-Baptiste Sibarita
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Laurent Cognet
- Institut d'Optique & CNRS, LP2N UMR 5298, 33400 Talence, France; Université de Bordeaux, Laboratoire Photonique Numérique et Nanosciences, UMR 5298, 33400 Talence, France
| | - Matthieu Sainlos
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France
| | - Ana Luisa Carvalho
- CNC-Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, Faculty of Sciences and Technology, University of Coimbra, 3004-517 Coimbra, Portugal
| | - Laurent Groc
- Université de Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France; CNRS, IINS UMR 5297, Bordeaux, France.
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Muscatelli F, Bouret SG. Wired for eating: how is an active feeding circuitry established in the postnatal brain? Curr Opin Neurobiol 2018; 52:165-171. [PMID: 30032064 DOI: 10.1016/j.conb.2018.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/01/2018] [Indexed: 12/27/2022]
Abstract
From birth, mammals have to find food and maximize caloric intake to ensure growth and survival. Suckling must be initiated quickly after birth and then maintained and controlled until weaning. It is a complex process involving interactions between sensory and motor neuronal pathways. Meanwhile, the control of food intake and energy homeostasis is progressively established via the development of hypothalamic circuits. The development of these circuits is influenced by hormonal and nutritional signals and can be disturbed in a variety of developmental disorders leading to long-term metabolic, behavioral and cognitive dysfunctions. This review summarizes our current knowledge of the neuronal circuits involved in early postnatal feeding processes.
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Affiliation(s)
- Françoise Muscatelli
- Institut de Neurobiologie de la Méditerranée, INSERM, U1249, Aix Marseille University, Marseille, France.
| | - Sébastien Gc Bouret
- The Saban Research Institute, Developmental Neuroscience Program & Diabetes and Obesity Program, Center for Endocrinology, Diabetes and Metabolism, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA 90027, USA; Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille 59045, France.
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Bell S, Maussion G, Jefri M, Peng H, Theroux JF, Silveira H, Soubannier V, Wu H, Hu P, Galat E, Torres-Platas SG, Boudreau-Pinsonneault C, O'Leary LA, Galat V, Turecki G, Durcan TM, Fon EA, Mechawar N, Ernst C. Disruption of GRIN2B Impairs Differentiation in Human Neurons. Stem Cell Reports 2018; 11:183-196. [PMID: 29937144 PMCID: PMC6067152 DOI: 10.1016/j.stemcr.2018.05.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 05/25/2018] [Accepted: 05/28/2018] [Indexed: 01/12/2023] Open
Abstract
Heterozygous loss-of-function mutations in GRIN2B, a subunit of the NMDA receptor, cause intellectual disability and language impairment. We developed clonal models of GRIN2B deletion and loss-of-function mutations in a region coding for the glutamate binding domain in human cells and generated neurons from a patient harboring a missense mutation in the same domain. Transcriptome analysis revealed extensive increases in genes associated with cell proliferation and decreases in genes associated with neuron differentiation, a result supported by extensive protein analyses. Using electrophysiology and calcium imaging, we demonstrate that NMDA receptors are present on neural progenitor cells and that human mutations in GRIN2B can impair calcium influx and membrane depolarization even in a presumed undifferentiated cell state, highlighting an important role for non-synaptic NMDA receptors. It may be this function, in part, which underlies the neurological disease observed in patients with GRIN2B mutations. Non-synaptic NMDA receptors are crucial for development of forebrain neural stem cells Mutations in GRIN2B impair neuronal differentiation Engineered patient repair restores cell differentiation Pharmacological blockade of NMDA receptors impairs differentiation
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Affiliation(s)
- Scott Bell
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Gilles Maussion
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Malvin Jefri
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Huashan Peng
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Jean-Francois Theroux
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Heika Silveira
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Vincent Soubannier
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, Montreal, QC H3A 2B4, Canada
| | - Hanrong Wu
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Peng Hu
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Ekaterina Galat
- Department of Pediatrics, Developmental Biology Program, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
| | - S Gabriela Torres-Platas
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Camille Boudreau-Pinsonneault
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Liam A O'Leary
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Vasiliy Galat
- Department of Pediatrics, Developmental Biology Program, Stanley Manne Children's Research Institute, Ann and Robert H. Lurie Children's Hospital of Chicago, Northwestern University, Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Gustavo Turecki
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Thomas M Durcan
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, Montreal, QC H3A 2B4, Canada
| | - Edward A Fon
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, Montreal, QC H3A 2B4, Canada
| | - Naguib Mechawar
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada
| | - Carl Ernst
- McGill University and Douglas Hospital Research Institute, Department of Psychiatry, 6875 LaSalle Boulevard, Frank Common Building, Room 2101.2, Verdun, Montreal, QC H4H 1R3, Canada.
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Vyklicky V, Krausova B, Cerny J, Ladislav M, Smejkalova T, Kysilov B, Korinek M, Danacikova S, Horak M, Chodounska H, Kudova E, Vyklicky L. Surface Expression, Function, and Pharmacology of Disease-Associated Mutations in the Membrane Domain of the Human GluN2B Subunit. Front Mol Neurosci 2018; 11:110. [PMID: 29681796 PMCID: PMC5897658 DOI: 10.3389/fnmol.2018.00110] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/20/2018] [Indexed: 12/20/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs), glutamate-gated ion channels, mediate signaling at the majority of excitatory synapses in the nervous system. Recent sequencing data for neurological and psychiatric patients have indicated numerous mutations in genes encoding for NMDAR subunits. Here, we present surface expression, functional, and pharmacological analysis of 11 de novo missense mutations of the human hGluN2B subunit (P553L; V558I; W607C; N615I; V618G; S628F; E657G; G820E; G820A; M824R; L825V) located in the pre-M1, M1, M2, M3, and M4 membrane regions. These variants were identified in patients with intellectual disability, developmental delay, epileptic symptomatology, and autism spectrum disorder. Immunofluorescence microscopy indicated that the ratio of surface-to-total NMDAR expression was reduced for hGluN1/hGluN2B(S628F) receptors and increased for for hGluN1/hGluN2B(G820E) receptors. Electrophysiological recordings revealed that agonist potency was altered in hGluN1/hGluN2B(W607C; N615I; and E657G) receptors and desensitization was increased in hGluN1/hGluN2B(V558I) receptors. The probability of channel opening of hGluN1/hGluN2B (V558I; W607C; V618G; and L825V) receptors was diminished ~10-fold when compared to non-mutated receptors. Finally, the sensitivity of mutant receptors to positive allosteric modulators of the steroid origin showed that glutamate responses induced in hGluN1/hGluN2B(V558I; W607C; V618G; and G820A) receptors were potentiated by 59–96% and 406-685% when recorded in the presence of 20-oxo-pregn-5-en-3β-yl sulfate (PE-S) and androst-5-en-3β-yl hemisuccinate (AND-hSuc), respectively. Surprisingly hGluN1/hGluN2B(L825V) receptors were strongly potentiated, by 197 and 1647%, respectively, by PE-S and AND-hSuc. Synaptic-like responses induced by brief glutamate application were also potentiated and the deactivation decelerated. Further, we have used homology modeling based on the available crystal structures of GluN1/GluN2B NMDA receptor followed by molecular dynamics simulations to try to relate the functional consequences of mutations to structural changes. Overall, these data suggest that de novo missense mutations of the hGluN2B subunit located in membrane domains lead to multiple defects that manifest by the NMDAR loss of function that can be rectified by steroids. Our results provide an opportunity for the development of new therapeutic neurosteroid-based ligands to treat diseases associated with hypofunction of the glutamatergic system.
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Affiliation(s)
- Vojtech Vyklicky
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Barbora Krausova
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Jiri Cerny
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Marek Ladislav
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia.,Department of Physiology, Faculty of Science, Charles University, Prague, Czechia
| | - Tereza Smejkalova
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Bohdan Kysilov
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Miloslav Korinek
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Sarka Danacikova
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia.,Department of Physiology, Faculty of Science, Charles University, Prague, Czechia
| | - Martin Horak
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
| | - Hana Chodounska
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences (CAS), Prague, Czechia
| | - Eva Kudova
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences (CAS), Prague, Czechia
| | - Ladislav Vyklicky
- Department of Cellular Neurophysiology, Institute of Physiology of the Czech Academy of Sciences (CAS), Prague, Czechia
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Long-Term Depression Is Independent of GluN2 Subunit Composition. J Neurosci 2018; 38:4462-4470. [PMID: 29593052 DOI: 10.1523/jneurosci.0394-18.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/16/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
NMDA receptors (NMDARs) mediate both long-term potentiation and long-term depression (LTD) and understanding how a single receptor can initiate both phenomena remains a major question in neuroscience. A prominent hypothesis implicates the NMDAR subunit composition, specifically GluN2A and GluN2B, in dictating the rules of synaptic plasticity. However, studies testing this hypothesis have yielded inconsistent and often contradictory results, especially for LTD. These inconsistent results may be due to challenges in the interpretation of subunit-selective pharmacology and in dissecting out the contributions of differential channel properties versus the interacting proteins unique to GluN2A or GluN2B. In this study, we address the pharmacological and biochemical challenges by using a single-neuron genetic approach to delete NMDAR subunits in conditional knock-out mice. In addition, the recently discovered non-ionotropic nature of NMDAR-dependent LTD allowed the rigorous assessment of unique subunit contributions to NMDAR-dependent LTD while eliminating the variable of differential charge transfer. Here we find that neither the GluN2A nor the GluN2B subunit is strictly necessary for either non-ionotropic or ionotropic LTD.SIGNIFICANCE STATEMENT NMDA receptors are key regulators of bidirectional synaptic plasticity. Understanding the mechanisms regulating bidirectional plasticity will guide development of therapeutic strategies to treat the dysfunctional synaptic plasticity in multiple neuropsychiatric disorders. Because of the unique properties of the NMDA receptor GluN2 subunits, they have been postulated to differentially affect synaptic plasticity. However, there has been significant controversy regarding the roles of the GluN2 subunits in synaptic long term depression (LTD). Using single-neuron knock-out of the GluN2 subunits, we show that LTD requires neither GluN2A nor GluN2B.
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Abstract
The c-Jun N-terminal kinase (JNK) signal transduction pathway is implicated in learning and memory. Here, we examined the role of JNK activation mediated by the JNK-interacting protein 1 (JIP1) scaffold protein. We compared male wild-type mice with a mouse model harboring a point mutation in the Jip1 gene that selectively blocks JIP1-mediated JNK activation. These male mutant mice exhibited increased NMDAR currents, increased NMDAR-mediated gene expression, and a lower threshold for induction of hippocampal long-term potentiation. The JIP1 mutant mice also displayed improved hippocampus-dependent spatial memory and enhanced associative fear conditioning. These results were confirmed using a second JIP1 mutant mouse model that suppresses JNK activity. Together, these observations establish that JIP1-mediated JNK activation contributes to the regulation of hippocampus-dependent, NMDAR-mediated synaptic plasticity and learning.SIGNIFICANCE STATEMENT The results of this study demonstrate that c-Jun N-terminal kinase (JNK) activation induced by the JNK-interacting protein 1 (JIP1) scaffold protein negatively regulates the threshold for induction of long-term synaptic plasticity through the NMDA-type glutamate receptor. This change in plasticity threshold influences learning. Indeed, mice with defects in JIP1-mediated JNK activation display enhanced memory in hippocampus-dependent tasks, such as contextual fear conditioning and Morris water maze, indicating that JIP1-JNK constrains spatial memory. This study identifies JIP1-mediated JNK activation as a novel molecular pathway that negatively regulates NMDAR-dependent synaptic plasticity and memory.
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Marballi KK, Gallitano AL. Immediate Early Genes Anchor a Biological Pathway of Proteins Required for Memory Formation, Long-Term Depression and Risk for Schizophrenia. Front Behav Neurosci 2018; 12:23. [PMID: 29520222 PMCID: PMC5827560 DOI: 10.3389/fnbeh.2018.00023] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 01/29/2018] [Indexed: 01/02/2023] Open
Abstract
While the causes of myriad medical and infectious illnesses have been identified, the etiologies of neuropsychiatric illnesses remain elusive. This is due to two major obstacles. First, the risk for neuropsychiatric disorders, such as schizophrenia, is determined by both genetic and environmental factors. Second, numerous genes influence susceptibility for these illnesses. Genome-wide association studies have identified at least 108 genomic loci for schizophrenia, and more are expected to be published shortly. In addition, numerous biological processes contribute to the neuropathology underlying schizophrenia. These include immune dysfunction, synaptic and myelination deficits, vascular abnormalities, growth factor disruption, and N-methyl-D-aspartate receptor (NMDAR) hypofunction. However, the field of psychiatric genetics lacks a unifying model to explain how environment may interact with numerous genes to influence these various biological processes and cause schizophrenia. Here we describe a biological cascade of proteins that are activated in response to environmental stimuli such as stress, a schizophrenia risk factor. The central proteins in this pathway are critical mediators of memory formation and a particular form of hippocampal synaptic plasticity, long-term depression (LTD). Each of these proteins is also implicated in schizophrenia risk. In fact, the pathway includes four genes that map to the 108 loci associated with schizophrenia: GRIN2A, nuclear factor of activated T-cells (NFATc3), early growth response 1 (EGR1) and NGFI-A Binding Protein 2 (NAB2); each of which contains the "Index single nucleotide polymorphism (SNP)" (most SNP) at its respective locus. Environmental stimuli activate this biological pathway in neurons, resulting in induction of EGR immediate early genes: EGR1, EGR3 and NAB2. We hypothesize that dysfunction in any of the genes in this pathway disrupts the normal activation of Egrs in response to stress. This may result in insufficient electrophysiologic, immunologic, and neuroprotective, processes that these genes normally mediate. Continued adverse environmental experiences, over time, may thereby result in neuropathology that gives rise to the symptoms of schizophrenia. By combining multiple genes associated with schizophrenia susceptibility, in a functional cascade triggered by neuronal activity, the proposed biological pathway provides an explanation for both the polygenic and environmental influences that determine the complex etiology of this mental illness.
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Affiliation(s)
- Ketan K. Marballi
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
| | - Amelia L. Gallitano
- Department of Basic Medical Sciences and Psychiatry, University of Arizona College of Medicine—Phoenix, Phoenix, AZ, United States
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Carta M, Srikumar BN, Gorlewicz A, Rebola N, Mulle C. Activity-dependent control of NMDA receptor subunit composition at hippocampal mossy fibre synapses. J Physiol 2018; 596:703-716. [PMID: 29218821 DOI: 10.1113/jp275226] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 11/27/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS CA3 pyramidal cells display input-specific differences in the subunit composition of synaptic NMDA receptors (NMDARs). Although at low density, GluN2B contributes significantly to NMDAR-mediated EPSCs at mossy fibre synapses. Long-term potentiation (LTP) of NMDARs triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. GluN2B subunits are essential for the expression of LTP of NMDARs at mossy fibre synapses. ABSTRACT Single neurons express NMDA receptors (NMDARs) with distinct subunit composition and biophysical properties that can be segregated in an input-specific manner. The dynamic control of the heterogeneous distribution of synaptic NMDARs is crucial to control input-dependent synaptic integration and plasticity. In hippocampal CA3 pyramidal cells from mice of both sexes, we found that mossy fibre (MF) synapses display a markedly lower proportion of GluN2B-containing NMDARs than associative/commissural synapses. The mechanism involved in such heterogeneous distribution of GluN2B subunits is not known. Here we show that long-term potentiation (LTP) of NMDARs, which is selectively expressed at MF-CA3 pyramidal cell synapses, triggers a modification in the subunit composition of synaptic NMDARs by insertion of GluN2B. This activity-dependent recruitment of GluN2B at mature MF-CA3 pyramidal cell synapses contrasts with the removal of GluN2B subunits at other glutamatergic synapses during development and in response to activity. Furthermore, although expressed at low levels, GluN2B is necessary for the expression of LTP of NMDARs at MF-CA3 pyramidal cell synapses. Altogether, we reveal a previously unknown activity-dependent regulation and function of GluN2B subunits that may contribute to the heterogeneous plasticity induction rules in CA3 pyramidal cells.
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Affiliation(s)
- Mario Carta
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, F-33000, Bordeaux, France
| | - Bettadapura N Srikumar
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, F-33000, Bordeaux, France
| | - Adam Gorlewicz
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, F-33000, Bordeaux, France
| | - Nelson Rebola
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, F-33000, Bordeaux, France
| | - Christophe Mulle
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, F-33000, Bordeaux, France
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Soto D, Olivella M, Grau C, Armstrong J, Alcon C, Gasull X, Gómez de Salazar M, Gratacòs-Batlle E, Ramos-Vicente D, Fernández-Dueñas V, Ciruela F, Bayés À, Sindreu C, López-Sala A, García-Cazorla À, Altafaj X. Rett-like Severe Encephalopathy Caused by a De Novo GRIN2B Mutation Is Attenuated by D-serine Dietary Supplement. Biol Psychiatry 2018; 83:160-172. [PMID: 28734458 DOI: 10.1016/j.biopsych.2017.05.028] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 04/26/2017] [Accepted: 05/17/2017] [Indexed: 01/13/2023]
Abstract
BACKGROUND N-Methyl-D-aspartate receptors (NMDARs) play pivotal roles in synaptic development, plasticity, neural survival, and cognition. Despite recent reports describing the genetic association between de novo mutations of NMDAR subunits and severe psychiatric diseases, little is known about their pathogenic mechanisms and potential therapeutic interventions. Here we report a case study of a 4-year-old Rett-like patient with severe encephalopathy carrying a missense de novo mutation in GRIN2B(p.P553T) coding for the GluN2B subunit of NMDAR. METHODS We generated a dynamic molecular model of mutant GluN2B-containing NMDARs. We expressed the mutation in cell lines and primary cultures, and we evaluated the putative morphological, electrophysiological, and synaptic plasticity alterations. Finally, we evaluated D-serine administration as a therapeutic strategy and translated it to the clinical practice. RESULTS Structural molecular modeling predicted a reduced pore size of mutant NMDARs. Electrophysiological recordings confirmed this prediction and also showed gating alterations, a reduced glutamate affinity associated with a strong decrease of NMDA-evoked currents. Moreover, GluN2B(P553T)-expressing neurons showed decreased spine density, concomitant with reduced NMDA-evoked currents and impaired NMDAR-dependent insertion of GluA1 at stimulated synapses. Notably, the naturally occurring coagonist D-serine was able to attenuate hypofunction of GluN2B(p.P553T)-containing NMDARs. Hence, D-serine dietary supplementation was initiated. Importantly, the patient has shown remarkable motor, cognitive, and communication improvements after 17 months of D-serine dietary supplementation. CONCLUSIONS Our data suggest that hypofunctional NMDARs containing GluN2B(p.P553T) can contribute to Rett-like encephalopathy and that their potentiation by D-serine treatment may underlie the associated clinical improvement.
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Affiliation(s)
- David Soto
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - Mireia Olivella
- Bioinfomatics and Medical Statistics Group, University of Vic-Central University of Catalonia, Barcelona, Spain
| | - Cristina Grau
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Judith Armstrong
- Genetics and Molecular Medicine Service, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Clara Alcon
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Clinical Foundations, University of Barcelona, Barcelona, Spain
| | - Xavier Gasull
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - Macarena Gómez de Salazar
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Esther Gratacòs-Batlle
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Biomedicine, University of Barcelona, Barcelona, Spain; August Pi i Sunyer Biomedical Research Institute, Barcelona, Spain
| | - David Ramos-Vicente
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Autonomous University of Barcelona, Bellaterra, Barcelona, Spain
| | - Víctor Fernández-Dueñas
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain; Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Francisco Ciruela
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Pathology and Experimental Therapeutics, University of Barcelona, Barcelona, Spain; Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain
| | - Àlex Bayés
- Molecular Physiology of the Synapse Laboratory, Biomedical Research Institute Sant Pau, Barcelona, Spain; Autonomous University of Barcelona, Bellaterra, Barcelona, Spain
| | - Carlos Sindreu
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain; Department of Clinical Foundations, University of Barcelona, Barcelona, Spain
| | - Anna López-Sala
- Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Àngels García-Cazorla
- Genetics and Molecular Medicine Service, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain; Department of Neurology, Neurometabolic Unit, Hospital Sant Joan de Déu and Centro de Investigación Biomédica en Red de Enfermedades Raras, Barcelona, Spain
| | - Xavier Altafaj
- Bellvitge Biomedical Research Institute-Unit of Neuropharmacology and Pain Group, University of Barcelona, Barcelona, Spain.
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Oyrer J, Maljevic S, Scheffer IE, Berkovic SF, Petrou S, Reid CA. Ion Channels in Genetic Epilepsy: From Genes and Mechanisms to Disease-Targeted Therapies. Pharmacol Rev 2018; 70:142-173. [PMID: 29263209 DOI: 10.1124/pr.117.014456] [Citation(s) in RCA: 163] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 10/02/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy is a common and serious neurologic disease with a strong genetic component. Genetic studies have identified an increasing collection of disease-causing genes. The impact of these genetic discoveries is wide reaching-from precise diagnosis and classification of syndromes to the discovery and validation of new drug targets and the development of disease-targeted therapeutic strategies. About 25% of genes identified in epilepsy encode ion channels. Much of our understanding of disease mechanisms comes from work focused on this class of protein. In this study, we review the genetic, molecular, and physiologic evidence supporting the pathogenic role of a number of different voltage- and ligand-activated ion channels in genetic epilepsy. We also review proposed disease mechanisms for each ion channel and highlight targeted therapeutic strategies.
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Affiliation(s)
- Julia Oyrer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Snezana Maljevic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Ingrid E Scheffer
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Samuel F Berkovic
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Steven Petrou
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
| | - Christopher A Reid
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia (J.O., S.M., I.E.S., S.P., C.A.R.); Department of Medicine, Austin Health, University of Melbourne, Heidelberg West, Melbourne, Australia (I.E.S., S.F.B.); and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia (I.E.S.)
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Affiliation(s)
- Hui Emma Zhang
- Centenary Institute and the Medical School of The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Margaret G Gall
- Centenary Institute and the Medical School of The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Mark D Gorrell
- Centenary Institute and the Medical School of The University of Sydney, Sydney, New South Wales 2006, Australia.
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68
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Bagasrawala I, Memi F, V. Radonjić N, Zecevic N. N-Methyl d-Aspartate Receptor Expression Patterns in the Human Fetal Cerebral Cortex. Cereb Cortex 2017; 27:5041-5053. [PMID: 27664962 PMCID: PMC6077866 DOI: 10.1093/cercor/bhw289] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 08/01/2016] [Accepted: 08/23/2016] [Indexed: 01/09/2023] Open
Abstract
N-methyl d-aspartate receptors (NMDARs), a subtype of glutamate receptor, have important functional roles in cellular activity and neuronal development. They are well-studied in rodent and adult human brains, but limited information is available about their distribution in the human fetal cerebral cortex. Here we show that 3 NMDAR subunits, NR1, NR2A, and NR2B, are expressed in the human cerebral cortex during the second trimester of gestation, a period of intense neurogenesis and synaptogenesis. With increasing fetal age, expression of the NMDAR-encoding genes Grin1 (NR1) and Grin2a (NR2A) increased while Grin2b (NR2B) expression decreased. The protein levels of all 3 subunits paralleled the changes in gene expression. On cryosections, all 3 subunits were expressed in proliferative ventricular and subventricular zones, in radial glia, and in intermediate progenitor cells, consistent with their role in the proliferation of cortical progenitor cells and in the determination of their respective fates. The detection of NR1, NR2A, and NR2B in both glutamatergic and GABAergic neurons of the cortical plate suggests the involvement of NMDARs in the maturation of human cortical neurons and in early synapse formation. Our results and previous studies in rodents suggest that NMDAR expression in the developing human brain is evolutionarily conserved.
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Affiliation(s)
- Inseyah Bagasrawala
- Department of Neuroscience, University of Connecticut Health, Farmington, CT 06030, USA
| | - Fani Memi
- Department of Neuroscience, University of Connecticut Health, Farmington, CT 06030, USA
| | - Nevena V. Radonjić
- Psychiatry Department, University of Connecticut Health, Farmington, CT 06030, USA
| | - Nada Zecevic
- Department of Neuroscience, University of Connecticut Health, Farmington, CT 06030, USA
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Lu F, Shao G, Wang Y, Guan S, Burlingame AL, Liu X, Liang X, Knox R, Ferriero DM, Jiang X. Hypoxia-ischemia modifies postsynaptic GluN2B-containing NMDA receptor complexes in the neonatal mouse brain. Exp Neurol 2017; 299:65-74. [PMID: 28993251 DOI: 10.1016/j.expneurol.2017.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 09/09/2017] [Accepted: 10/05/2017] [Indexed: 01/08/2023]
Abstract
The N-methyl-d-aspartate-type glutamate receptor (NMDAR)-associated multiprotein complexes are indispensable for synaptic plasticity and cognitive functions. While purification and proteomic analyses of these signaling complexes have been performed in adult rodent and human brain, much less is known about the protein composition of NMDAR complexes in the developing brain and their modifications by neonatal hypoxic-ischemic (HI) brain injury. In this study, the postsynaptic density proteins were prepared from postnatal day 9 naïve, sham-operated and HI-injured mouse cortex. The GluN2B-containing NMDAR complexes were purified by immunoprecipitation with a mouse GluN2B antibody and subjected to mass spectrometry analysis for determination of the GluN2B binding partners. A total of 71 proteins of different functional categories were identified from the naïve animals as native GluN2B-interacting partners in the developing mouse brain. Neonatal HI reshaped the postsynaptic GluN2B interactome by recruiting new proteins, including multiple kinases, into the complexes; and modifying the existing associations within 1h of reperfusion. The early responses of postsynaptic NMDAR complexes and their related signaling networks may contribute to molecular processes leading to cell survival or death, brain damage and/or neurological disorders in term infants with neonatal encephalopathy.
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Affiliation(s)
- Fuxin Lu
- Department of Pediatrics, University of California San Francisco, CA, USA
| | - Guo Shao
- Inner Mongolia Key Laboratory of Hypoxic Translational Medicine, Baotou Medical College, Baotou, China
| | - Yongqiang Wang
- Department of Cellular & Molecular Pharmacology, University of California San Francisco, CA, USA; Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Shenheng Guan
- Department of Pharmaceutical Chemistry, University of California San Francisco, CA, USA
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, CA, USA
| | - Xuemei Liu
- Central Laboratory, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Xiao Liang
- Central Laboratory, Dongfang Hospital, Beijing University of Chinese Medicine, Beijing, China
| | - Renatta Knox
- Department of Pediatrics, Weill Cornell Medical College, New York, NY, USA
| | - Donna M Ferriero
- Department of Pediatrics, University of California San Francisco, CA, USA; Department of Neurology, University of California San Francisco, CA, USA
| | - Xiangning Jiang
- Department of Pediatrics, University of California San Francisco, CA, USA.
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Berrout L, Isokawa M. Ghrelin upregulates the phosphorylation of the GluN2B subunit of the NMDA receptor by activating GHSR1a and Fyn in the rat hippocampus. Brain Res 2017; 1678:20-26. [PMID: 28993142 DOI: 10.1016/j.brainres.2017.09.028] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/03/2017] [Accepted: 09/24/2017] [Indexed: 11/18/2022]
Abstract
Ghrelin and its receptor GHSR1a have been shown to exert numerous physiological functions in the brain, in addition to the well-established orexigenic role in the hypothalamus. Earlier work indicated that ghrelin stimulated the phosphorylation of the GluN1 subunit of the NMDA receptor (NMDAR) and enhanced synaptic transmission in the hippocampus. In the present study, we report that the exogenous application of ghrelin increased GluN2B phosphorylation. This increase was independent of GluN2B subunit activity or NMDAR channel activity. However, it depended on the activation of GHSR1a and Fyn as it was blocked by D-Lys3-GHRP-6 and PP2, respectively. Inhibitors for G-protein-regulated second messengers, such as Rp-cAMP, H89, TBB, ryanodine, and thapsigargin, unexpectedly enhanced GluN2B phosphorylation, suggesting that cAMP, PKA, casein kinase II, and cytosolic calcium signaling may oppose to the effect of ghrelin on the phosphorylation of GluN2B. Our findings suggest that 1) GluN2B is likely a molecular target of ghrelin and GHSR1a-driven signaling cascades, and 2) the ghrelin-mediated phosphorylation of GluN2B depends on Fyn activation under complex negative regulation by other second messengers.
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Affiliation(s)
- Liza Berrout
- Department of Health and Biomedical Sciences, University of Texas Rio Grande Valley, 1W University Blvd., Brownsville, TX 78520, United States
| | - Masako Isokawa
- Department of Health and Biomedical Sciences, University of Texas Rio Grande Valley, 1W University Blvd., Brownsville, TX 78520, United States.
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Varghese M, Keshav N, Jacot-Descombes S, Warda T, Wicinski B, Dickstein DL, Harony-Nicolas H, De Rubeis S, Drapeau E, Buxbaum JD, Hof PR. Autism spectrum disorder: neuropathology and animal models. Acta Neuropathol 2017; 134:537-566. [PMID: 28584888 PMCID: PMC5693718 DOI: 10.1007/s00401-017-1736-4] [Citation(s) in RCA: 287] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 12/13/2022]
Abstract
Autism spectrum disorder (ASD) has a major impact on the development and social integration of affected individuals and is the most heritable of psychiatric disorders. An increase in the incidence of ASD cases has prompted a surge in research efforts on the underlying neuropathologic processes. We present an overview of current findings in neuropathology studies of ASD using two investigational approaches, postmortem human brains and ASD animal models, and discuss the overlap, limitations, and significance of each. Postmortem examination of ASD brains has revealed global changes including disorganized gray and white matter, increased number of neurons, decreased volume of neuronal soma, and increased neuropil, the last reflecting changes in densities of dendritic spines, cerebral vasculature and glia. Both cortical and non-cortical areas show region-specific abnormalities in neuronal morphology and cytoarchitectural organization, with consistent findings reported from the prefrontal cortex, fusiform gyrus, frontoinsular cortex, cingulate cortex, hippocampus, amygdala, cerebellum and brainstem. The paucity of postmortem human studies linking neuropathology to the underlying etiology has been partly addressed using animal models to explore the impact of genetic and non-genetic factors clinically relevant for the ASD phenotype. Genetically modified models include those based on well-studied monogenic ASD genes (NLGN3, NLGN4, NRXN1, CNTNAP2, SHANK3, MECP2, FMR1, TSC1/2), emerging risk genes (CHD8, SCN2A, SYNGAP1, ARID1B, GRIN2B, DSCAM, TBR1), and copy number variants (15q11-q13 deletion, 15q13.3 microdeletion, 15q11-13 duplication, 16p11.2 deletion and duplication, 22q11.2 deletion). Models of idiopathic ASD include inbred rodent strains that mimic ASD behaviors as well as models developed by environmental interventions such as prenatal exposure to sodium valproate, maternal autoantibodies, and maternal immune activation. In addition to replicating some of the neuropathologic features seen in postmortem studies, a common finding in several animal models of ASD is altered density of dendritic spines, with the direction of the change depending on the specific genetic modification, age and brain region. Overall, postmortem neuropathologic studies with larger sample sizes representative of the various ASD risk genes and diverse clinical phenotypes are warranted to clarify putative etiopathogenic pathways further and to promote the emergence of clinically relevant diagnostic and therapeutic tools. In addition, as genetic alterations may render certain individuals more vulnerable to developing the pathological changes at the synapse underlying the behavioral manifestations of ASD, neuropathologic investigation using genetically modified animal models will help to improve our understanding of the disease mechanisms and enhance the development of targeted treatments.
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Affiliation(s)
- Merina Varghese
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Neha Keshav
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Sarah Jacot-Descombes
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Unit of Psychiatry, Department of Children and Teenagers, University Hospitals and School of Medicine, Geneva, CH-1205, Switzerland
| | - Tahia Warda
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Bridget Wicinski
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Dara L Dickstein
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Pathology, Uniformed Services University of the Health Sciences, Bethesda, MD, 20814, USA
| | - Hala Harony-Nicolas
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Silvia De Rubeis
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Elodie Drapeau
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Joseph D Buxbaum
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Patrick R Hof
- Fishberg Department of Neuroscience, Icahn School of Medicine at Mount Sinai, Box 1639, One Gustave L. Levy Place, New York, NY, 10029, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
- Seaver Autism Center for Research and Treatment, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
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72
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Kim M, Minoux M, Piaia A, Kueng B, Gapp B, Weber D, Haller C, Barbieri S, Namoto K, Lorenz T, Wirsching J, Bassilana F, Dietrich W, Rijli FM, Ksiazek I. DPP9 enzyme activity controls survival of mouse migratory tongue muscle progenitors and its absence leads to neonatal lethality due to suckling defect. Dev Biol 2017; 431:297-308. [PMID: 28887018 DOI: 10.1016/j.ydbio.2017.09.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Revised: 08/16/2017] [Accepted: 09/03/2017] [Indexed: 01/23/2023]
Abstract
Dipeptidyl peptidase 9 (DPP9) is an intracellular N-terminal post-proline-cleaving enzyme whose physiological function remains largely unknown. We investigated the role of DPP9 enzyme in vivo by characterizing knock-in mice expressing a catalytically inactive mutant form of DPP9 (S729A; DPP9ki/ki mice). We show that DPP9ki/ki mice die within 12-18h after birth. The neonatal lethality can be rescued by manual feeding, indicating that a suckling defect is the primary cause of neonatal lethality. The suckling defect results from microglossia, and is characterized by abnormal formation of intrinsic muscles at the distal tongue. In DPP9ki/ki mice, the number of occipital somite-derived migratory muscle progenitors, forming distal tongue intrinsic muscles, is reduced due to increased apoptosis. In contrast, intrinsic muscles of the proximal tongue and extrinsic tongue muscles, which derive from head mesoderm, develop normally in DPP9ki/ki mice. Thus, lack of DPP9 activity in mice leads to impaired tongue development, suckling defect and subsequent neonatal lethality due to impaired survival of a specific subset of migratory tongue muscle progenitors.
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Affiliation(s)
- Munkyung Kim
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Maryline Minoux
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Alessandro Piaia
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Benjamin Kueng
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Berangere Gapp
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Delphine Weber
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Corinne Haller
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Samuel Barbieri
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Kenji Namoto
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Thorsten Lorenz
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | - Johann Wirsching
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland
| | | | | | - Filippo M Rijli
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Iwona Ksiazek
- Novartis Institute for Biomedical Research, CH-4056 Basel, Switzerland.
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73
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Lang E, Mallien AS, Vasilescu AN, Hefter D, Luoni A, Riva MA, Borgwardt S, Sprengel R, Lang UE, Gass P, Inta D. Molecular and cellular dissection of NMDA receptor subtypes as antidepressant targets. Neurosci Biobehav Rev 2017; 84:352-358. [PMID: 28843752 DOI: 10.1016/j.neubiorev.2017.08.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 07/26/2017] [Accepted: 08/17/2017] [Indexed: 10/19/2022]
Abstract
A growing body of evidence supports the idea that drugs targeting the glutamate system may represent a valuable therapeutic alternative in major depressive disorders (MDD). The rapid and prolonged mood elevating effect of the NMDA receptor (NMDAR) antagonist ketamine has been studied intensely. However, its clinical use is hampered by deleterious side-effects, such as psychosis. Therefore, a better understanding of the mechanisms of the psychotropic effects after NMDAR blockade is necessary to develop glutamatergic antidepressants with improved therapeutic profile. Here we review recent experimental data that addressed molecular/cellular determinants of the antidepressant effect mediated by inactivating NMDAR subtypes. We refer to results obtained both in pharmacological and genetic animal models, ranging from global to conditional NMDAR manipulation. Our main focus is on the contribution of different NMDAR subtypes to the psychoactive effects induced by NMDAR ablation/blockade. We review data analyzing the effect of NMDAR subtype deletions limited to specific neuronal populations/brain areas in the regulation of mood. Altogether, these studies suggest effective and putative specific NMDAR drug targets for MDD treatment.
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Affiliation(s)
- Elisabeth Lang
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Anne S Mallien
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Andrei-Nicolae Vasilescu
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Dimitri Hefter
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Alessia Luoni
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Marco A Riva
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milano, Italy
| | - Stefan Borgwardt
- Department of Psychiatry (UPK), University of Basel, Switzerland
| | - Rolf Sprengel
- Max-Planck Research Group at the Institute for Anatomy and Cell Biology, Heidelberg University, Germany
| | - Undine E Lang
- Department of Psychiatry (UPK), University of Basel, Switzerland
| | - Peter Gass
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany
| | - Dragos Inta
- Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Medical Faculty Mannheim, University of Heidelberg, Germany; Department of Psychiatry (UPK), University of Basel, Switzerland.
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74
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A Rare Variant Identified Within the GluN2B C-Terminus in a Patient with Autism Affects NMDA Receptor Surface Expression and Spine Density. J Neurosci 2017; 37:4093-4102. [PMID: 28283559 DOI: 10.1523/jneurosci.0827-16.2017] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 02/01/2017] [Accepted: 02/04/2017] [Indexed: 12/11/2022] Open
Abstract
NMDA receptors (NMDARs) are ionotropic glutamate receptors that are crucial for neuronal development and higher cognitive processes. NMDAR dysfunction is involved in a variety of neurological and psychiatric diseases; however, the mechanistic link between the human pathology and NMDAR dysfunction is poorly understood. Rare missense variants within NMDAR subunits have been identified in numerous patients with mental or neurological disorders. We specifically focused on the GluN2B NMDAR subunit, which is highly expressed in the hippocampus and cortex throughout development. We analyzed several variants located in the GluN2B C terminus and found that three variants in patients with autism (S1415L) or schizophrenia (L1424F and S1452F) (S1413L, L1422F, and S1450F in rodents, respectively) displayed impaired binding to membrane-associated guanylate kinase (MAGUK) proteins. In addition, we observed a deficit in surface expression for GluN2B S1413L. Furthermore, there were fewer dendritic spines in GluN2B S1413L-expressing neurons. Importantly, synaptic NMDAR currents in neurons transfected with GluN2B S1413L in GluN2A/B-deficient mouse brain slices revealed only partial rescue of synaptic current amplitude. Functional properties of GluN2B S1413L in recombinant systems revealed no change in receptor properties, consistent with synaptic defects being the result of reduced trafficking and targeting of GluN2B S1413L to the synapse. Therefore, we find that GluN2B S1413L displays deficits in NMDAR trafficking, synaptic currents, and spine density, raising the possibility that this mutation may contribute to the phenotype in this autism patient. More broadly, our research demonstrates that the targeted study of certain residues in NMDARs based on rare variants identified in patients is a powerful approach to studying receptor function.SIGNIFICANCE STATEMENT We have used a "bedside-to-bench" approach to investigate the functional regulation of NMDA receptors (NMDARs). Using information from deep sequencing of patients with neurological or psychiatric disorders, we investigated missense variants identified in the intracellular C-terminal domain of the GluN2B NMDAR subunit. We found several variants that displayed altered properties. In particular, one variant identified in a patient with autism, human GluN2B S1415L, displayed reduced surface expression and binding to PSD-95. Furthermore expression of GluN2B S1415L (S1413L in mouse) showed a deficit in rescue of synaptic NMDAR currents and fewer dendritic spines, consistent with other reports of spine abnormalities being associated with autism. More broadly, we demonstrate that using patient data is an effective approach to probing the structure/function relationship of NMDARs.
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75
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Pfisterer U, Khodosevich K. Neuronal survival in the brain: neuron type-specific mechanisms. Cell Death Dis 2017; 8:e2643. [PMID: 28252642 PMCID: PMC5386560 DOI: 10.1038/cddis.2017.64] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/24/2017] [Accepted: 01/31/2017] [Indexed: 12/19/2022]
Abstract
Neurogenic regions of mammalian brain produce many more neurons that will eventually survive and reach a mature stage. Developmental cell death affects both embryonically produced immature neurons and those immature neurons that are generated in regions of adult neurogenesis. Removal of substantial numbers of neurons that are not yet completely integrated into the local circuits helps to ensure that maturation and homeostatic function of neuronal networks in the brain proceed correctly. External signals from brain microenvironment together with intrinsic signaling pathways determine whether a particular neuron will die. To accommodate this signaling, immature neurons in the brain express a number of transmembrane factors as well as intracellular signaling molecules that will regulate the cell survival/death decision, and many of these factors cease being expressed upon neuronal maturation. Furthermore, pro-survival factors and intracellular responses depend on the type of neuron and region of the brain. Thus, in addition to some common neuronal pro-survival signaling, different types of neurons possess a variety of 'neuron type-specific' pro-survival constituents that might help them to adapt for survival in a certain brain region. This review focuses on how immature neurons survive during normal and impaired brain development, both in the embryonic/neonatal brain and in brain regions associated with adult neurogenesis, and emphasizes neuron type-specific mechanisms that help to survive for various types of immature neurons. Importantly, we mainly focus on in vivo data to describe neuronal survival specifically in the brain, without extrapolating data obtained in the PNS or spinal cord, and thus emphasize the influence of the complex brain environment on neuronal survival during development.
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Affiliation(s)
- Ulrich Pfisterer
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
| | - Konstantin Khodosevich
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen, Denmark
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76
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Swanger SA, Chen W, Wells G, Burger PB, Tankovic A, Bhattacharya S, Strong KL, Hu C, Kusumoto H, Zhang J, Adams DR, Millichap JJ, Petrovski S, Traynelis SF, Yuan H. Mechanistic Insight into NMDA Receptor Dysregulation by Rare Variants in the GluN2A and GluN2B Agonist Binding Domains. Am J Hum Genet 2016; 99:1261-1280. [PMID: 27839871 PMCID: PMC5142120 DOI: 10.1016/j.ajhg.2016.10.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/03/2016] [Indexed: 12/30/2022] Open
Abstract
Epilepsy and intellectual disability are associated with rare variants in the GluN2A and GluN2B (encoded by GRIN2A and GRIN2B) subunits of the N-methyl-D-aspartate receptor (NMDAR), a ligand-gated ion channel with essential roles in brain development and function. By assessing genetic variation across GluN2 domains, we determined that the agonist binding domain, transmembrane domain, and the linker regions between these domains were particularly intolerant to functional variation. Notably, the agonist binding domain of GluN2B exhibited significantly more variation intolerance than that of GluN2A. To understand the ramifications of missense variation in the agonist binding domain, we investigated the mechanisms by which 25 rare variants in the GluN2A and GluN2B agonist binding domains dysregulated NMDAR activity. When introduced into recombinant human NMDARs, these rare variants identified in individuals with neurologic disease had complex, and sometimes opposing, consequences on agonist binding, channel gating, receptor biogenesis, and forward trafficking. Our approach combined quantitative assessments of these effects to estimate the overall impact on synaptic and non-synaptic NMDAR function. Interestingly, similar neurologic diseases were associated with both gain- and loss-of-function variants in the same gene. Most rare variants in GluN2A were associated with epilepsy, whereas GluN2B variants were associated with intellectual disability with or without seizures. Finally, discerning the mechanisms underlying NMDAR dysregulation by these rare variants allowed investigations of pharmacologic strategies to correct NMDAR function.
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Affiliation(s)
- Sharon A Swanger
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wenjuan Chen
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gordon Wells
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Pieter B Burger
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Anel Tankovic
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Katie L Strong
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Chun Hu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hirofumi Kusumoto
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jing Zhang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David R Adams
- Undiagnosed Diseases Network, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - John J Millichap
- Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Slavé Petrovski
- Department of Medicine, The University of Melbourne, Austin Health and Royal Melbourne Hospital, Melbourne, VIC 3050, Australia
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Hongjie Yuan
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
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77
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Ballesteros JJ, Buschler A, Köhr G, Manahan-Vaughan D. Afferent Input Selects NMDA Receptor Subtype to Determine the Persistency of Hippocampal LTP in Freely Behaving Mice. Front Synaptic Neurosci 2016; 8:33. [PMID: 27818632 PMCID: PMC5073893 DOI: 10.3389/fnsyn.2016.00033] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/26/2016] [Indexed: 01/07/2023] Open
Abstract
The glutamatergic N-methyl-D-aspartate receptor (NMDAR) is critically involved in many forms of hippocampus-dependent memory that may be enabled by synaptic plasticity. Behavioral studies with NMDAR antagonists and NMDAR subunit (GluN2) mutants revealed distinct contributions from GluN2A- and GluN2B-containing NMDARs to rapidly and slowly acquired memory performance. Furthermore, studies of synaptic plasticity, in genetically modified mice in vitro, suggest that GluN2A and GluN2B may contribute in different ways to the induction and longevity of synaptic plasticity. In contrast to the hippocampal slice preparation, in behaving mice, the afferent frequencies that induce synaptic plasticity are very restricted and specific. In fact, it is the stimulus pattern and not variations in afferent frequency that determine the longevity of long-term potentiation (LTP) in vivo. Here, we explored the contribution of GluN2A and GluN2B to LTP of differing magnitudes and persistence in freely behaving mice. We applied differing high-frequency stimulation (HFS) patterns at 100 Hz to the hippocampal CA1 region, to induce NMDAR-dependent LTP in wild-type (WT) mice, that endured for <1 h (early (E)-LTP), (LTP, 2–4 h) or >24 h (late (L)-LTP). In GluN2A-knockout (KO) mice, E-LTP (HFS, 50 pulses) was significantly reduced in magnitude and duration, whereas LTP (HFS, 2 × 50 pulses) and L-LTP (HFS, 4 × 50 pulses) were unaffected compared to responses in WT animals. By contrast, pharmacological antagonism of GluN2B in WT had no effect on E-LTP but significantly prevented LTP. E-LTP and LTP were significantly impaired by GluN2B antagonism in GluN2A-KO mice. These data indicate that the pattern of afferent stimulation is decisive for the recruitment of distinct GluN2A and GluN2B signaling pathways that in turn determine the persistency of hippocampal LTP. Whereas brief bursts of patterned stimulation preferentially recruit GluN2A and lead to weak and short-lived forms of LTP, prolonged, more intense, afferent activation recruits GluN2B and leads to robust and persistent LTP. These unique signal-response properties of GluN2A and GluN2B enable qualitative differentiation of information encoding in hippocampal synapses.
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Affiliation(s)
- Jesús J Ballesteros
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany
| | - Arne Buschler
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum Bochum, Germany
| | - Georg Köhr
- Max Planck Institute for Medical Research Heidelberg, Germany
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78
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Hu C, Chen W, Myers SJ, Yuan H, Traynelis SF. Human GRIN2B variants in neurodevelopmental disorders. J Pharmacol Sci 2016; 132:115-121. [PMID: 27818011 PMCID: PMC5125235 DOI: 10.1016/j.jphs.2016.10.002] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 11/25/2022] Open
Abstract
The development of whole exome/genome sequencing technologies has given rise to an unprecedented volume of data linking patient genomic variability to brain disorder phenotypes. A surprising number of variants have been found in the N-methyl-d-aspartate receptor (NMDAR) gene family, with the GRIN2B gene encoding the GluN2B subunit being implicated in many cases of neurodevelopmental disorders, which are psychiatric conditions originating in childhood and include language, motor, and learning disorders, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), developmental delay, epilepsy, and schizophrenia. The GRIN2B gene plays a crucial role in normal neuronal development and is important for learning and memory. Mutations in human GRIN2B were distributed throughout the entire gene in a number of patients with various neuropsychiatric and developmental disorders. Studies that provide functional analysis of variants are still lacking, however current analysis of de novo variants that segregate with disease cases such as intellectual disability, developmental delay, ASD or epileptic encephalopathies reveal altered NMDAR function. Here, we summarize the current reports of disease-associated variants in GRIN2B from patients with multiple neurodevelopmental disorders, and discuss implications, highlighting the importance of functional analysis and precision medicine therapies.
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Affiliation(s)
- Chun Hu
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Wenjuan Chen
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Scott J Myers
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Hongjie Yuan
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA.
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79
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Isoo N, Ohno T, Isowaki M, Fukuda S, Murabe N, Mizukami H, Ozawa K, Mishina M, Sakurai M. The decline in synaptic GluN2B and rise in inhibitory neurotransmission determine the end of a critical period. Sci Rep 2016; 6:34196. [PMID: 27677249 PMCID: PMC5039748 DOI: 10.1038/srep34196] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 09/09/2016] [Indexed: 12/20/2022] Open
Abstract
Neuronal plasticity is especially active in the young, during short windows of time termed critical periods, and loss of a critical period leads to functional limitations in the adults. The mechanism that governs the length of critical periods remains unknown. Here we show that levels of the NMDA receptor GluN2B subunit, which functions as a Ca2+ channel, declines in spinal cord synapses toward the end of the critical period for activity-dependent corticospinal synapse elimination. This period could be prolonged by blocking the decline of GluN2B, and after its termination the critical period could be reopened through upregulation of GluN2B. It is known that inhibitory neural activity increases with development in the CNS including the spinal cord. Suppression of the increasing inhibitory activity using low-dose strychnine also prolonged this critical period. During the strychnine-widened time window, Ca2+ influx through GluN2B channels returned to a level comparable to that seen during the critical period, though the level of GluN2B was slightly reduced. These findings indicate that loss of GluN2B subunits and the associated reduction in Ca2+ influx determines the end of the critical period in our in vitro CS system.
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Affiliation(s)
- Noriko Isoo
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Takae Ohno
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Mutsumi Isowaki
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Satoshi Fukuda
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Naoyuki Murabe
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimono, Tochigi 329-0498, Japan
| | - Keiya Ozawa
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, 3311-1 Yakushiji, Shimono, Tochigi 329-0498, Japan.,Division of Genetic Therapeutics, the Institute of Medical Science, the University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Masayoshi Mishina
- Department of Molecular Neurobiology &Pharmacology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.,Brain Science Laboratory, The Research Organization of Science and Technology, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Masaki Sakurai
- Department of Physiology, Teikyo University School of Medicine, 2-11-1 Kaga, Itabashi-ku, Tokyo 173-8605, Japan
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80
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Tovar KR, Westbrook GL. Modulating synaptic NMDA receptors. Neuropharmacology 2016; 112:29-33. [PMID: 27565459 DOI: 10.1016/j.neuropharm.2016.08.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 08/17/2016] [Indexed: 12/14/2022]
Abstract
Recent structural information on ligand-gated glutamate receptors and newly-discovered clinical uses for NMDA receptor antagonists has renewed interest in understanding the mechanisms of drug action at these receptors. Although the voltage-dependence and calcium permeability of NMDA receptors are well-studied, the mechanisms affecting the time course of synaptic NMDA receptor activation may be of more therapeutic value by serving as a rheostat for the total synaptic response. The NMDA receptor-mediated EPSC time course has been thought of as a fixed parameter based simply on receptor subunit composition as variably constrained by anatomical and developmental expression patterns, albeit subject to modification by kinetic behaviors such as modal gating. However, the EPSC time course also can be manipulated by endogenous and exogenous ligands. In this commentary we discuss insights into the in situ composition and kinetic behavior of synaptic NMDA receptors and propose new opportunities to target modulatory sites on NMDA receptors and to develop useful therapeutics. The emerging data on the atomic structure of NMDA receptors and knowledge of the kinetics of native receptors in neurons provide a roadmap in this regard. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.
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Affiliation(s)
- Kenneth R Tovar
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, United States.
| | - Gary L Westbrook
- Vollum Institute, Oregon Health & Science University, Portland, OR 97239, United States.
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81
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Hashimoto M, Hossain S, Al Mamun A, Matsuzaki K, Arai H. Docosahexaenoic acid: one molecule diverse functions. Crit Rev Biotechnol 2016; 37:579-597. [DOI: 10.1080/07388551.2016.1207153] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Michio Hashimoto
- Department of Environmental Physiology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Shahdat Hossain
- Department of Environmental Physiology, Shimane University Faculty of Medicine, Izumo, Japan
- Department of Biochemistry and Molecular Biology, Jahangirnagar University, Dhaka, Bangladesh
| | - Abdullah Al Mamun
- Department of Environmental Physiology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Kentaro Matsuzaki
- Department of Environmental Physiology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Hiroyuki Arai
- Department of Geriatrics and Gerontology, Division of Brain Sciences, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
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82
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Ueno M, Okamura T, Mishina M, Ishizaka Y. Modulation of long interspersed nuclear element-1 in the mouse hippocampus during maturation. Mob Genet Elements 2016; 6:e1211980. [PMID: 27583186 DOI: 10.1080/2159256x.2016.1211980] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 07/06/2016] [Accepted: 07/06/2016] [Indexed: 10/21/2022] Open
Abstract
BACKGROUND Retrotransposition of long interspersed nuclear element-1 (L1-RTP) is proposed to contribute to central nervous system (CNS) plasticity by inducing mosaicism of neuronal cells. Clinical studies have identified increased L1 copy numbers in the brains of patients with psychiatric disorders. These observations implicate that L1-RTP is important for neurogenesis and that its deregulation represents a risk factor for mental disorders. However, no supportive evidence is available for understanding the importance of L1-RTP in CNS function. FINDINGS To explore the physiological role of L1-RTP in CNS, we examined the L1 copy number during maturation. Interestingly, the L1 copy number increased after birth in the mouse hippocampus, but not the frontal lobe, with maximal copy numbers found in 8-week-old mice. This age-dependent L1 increase was abolished by administration of a reverse-transcriptase inhibitor, stavudine (d4T), which showed no toxic effects. Notably, the age-dependent L1 increase was attenuated by post-weaning social isolation (SI) stress, a well-known intervention for inducing psychiatric disorders in mice, or deletion of the NR2A gene that encodes a subunit of the glutamate receptor. Moreover, the negative effects of SI stress on L1-RTP were partially restored by environmental enrichment with voluntary running, but not by fluoxetine, a commonly used anti-psychiatric drug. Finally, behavioral experiments revealed that learning memory was defective in d4T-treated mice, which was similarly observed in mice raised under SI stress. CONCLUSION We detected the modulation of L1-RTP in the hippocampus during maturation of the CNS. In a recent study, we demonstrated that stimulants such as methamphetamine and cocaine were active in the induction of L1-RTP in neuronal cells, and previous studies have shown that NR2A-deficient mice are susceptible to mental abnormality. Herein, our data support the notion that the age-dependent modulation of L1-RTP is involved in genome differentiation in the hippocampus, and that modulation defects are linked to the development of psychiatric disorders.
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Affiliation(s)
- Mikako Ueno
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine , Shinjuku-ku, Tokyo Japan
| | - Tadashi Okamura
- Department of Laboratory Animal Medicine, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan; Section of Animal Models, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan
| | - Masayoshi Mishina
- Brain Science Laboratory, The Research Organization of Science and Technology, Ritsumeikan University , Kusatsu, Shiga, Japan
| | - Yukihito Ishizaka
- Department of Intractable Diseases, Research Institute, National Center for Global Health and Medicine , Shinjuku-ku, Tokyo Japan
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83
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Curcio M, Salazar IL, Mele M, Canzoniero LMT, Duarte CB. Calpains and neuronal damage in the ischemic brain: The swiss knife in synaptic injury. Prog Neurobiol 2016; 143:1-35. [PMID: 27283248 DOI: 10.1016/j.pneurobio.2016.06.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/22/2016] [Accepted: 05/09/2016] [Indexed: 12/26/2022]
Abstract
The excessive extracellular accumulation of glutamate in the ischemic brain leads to an overactivation of glutamate receptors with consequent excitotoxic neuronal death. Neuronal demise is largely due to a sustained activation of NMDA receptors for glutamate, with a consequent increase in the intracellular Ca(2+) concentration and activation of calcium- dependent mechanisms. Calpains are a group of Ca(2+)-dependent proteases that truncate specific proteins, and some of the cleavage products remain in the cell, although with a distinct function. Numerous studies have shown pre- and post-synaptic effects of calpains on glutamatergic and GABAergic synapses, targeting membrane- associated proteins as well as intracellular proteins. The resulting changes in the presynaptic proteome alter neurotransmitter release, while the cleavage of postsynaptic proteins affects directly or indirectly the activity of neurotransmitter receptors and downstream mechanisms. These alterations also disturb the balance between excitatory and inhibitory neurotransmission in the brain, with an impact in neuronal demise. In this review we discuss the evidence pointing to a role for calpains in the dysregulation of excitatory and inhibitory synapses in brain ischemia, at the pre- and post-synaptic levels, as well as the functional consequences. Although targeting calpain-dependent mechanisms may constitute a good therapeutic approach for stroke, specific strategies should be developed to avoid non-specific effects given the important regulatory role played by these proteases under normal physiological conditions.
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Affiliation(s)
- Michele Curcio
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Ivan L Salazar
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Doctoral Programme in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra (IIIUC), 3030-789 Coimbra, Portugal
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; Department of Life Sciences, University of Coimbra, 3000-456 Coimbra, Portugal.
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84
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Zhang H, Kang E, Wang Y, Yang C, Yu H, Wang Q, Chen Z, Zhang C, Christian KM, Song H, Ming GL, Xu Z. Brain-specific Crmp2 deletion leads to neuronal development deficits and behavioural impairments in mice. Nat Commun 2016; 7:ncomms11773. [PMID: 27249678 PMCID: PMC4895353 DOI: 10.1038/ncomms11773] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 04/28/2016] [Indexed: 02/07/2023] Open
Abstract
Several genome- and proteome-wide studies have associated transcription and translation changes of CRMP2 (collapsing response mediator protein 2) with psychiatric disorders, yet little is known about its function in the developing or adult mammalian brain in vivo. Here we show that brain-specific Crmp2 knockout (cKO) mice display molecular, cellular, structural and behavioural deficits, many of which are reminiscent of neural features and symptoms associated with schizophrenia. cKO mice exhibit enlarged ventricles and impaired social behaviour, locomotor activity, and learning and memory. Loss of Crmp2 in the hippocampus leads to reduced long-term potentiation, abnormal NMDA receptor composition, aberrant dendrite development and defective synapse formation in CA1 neurons. Furthermore, knockdown of crmp2 specifically in newborn neurons results in stage-dependent defects in their development during adult hippocampal neurogenesis. Our findings reveal a critical role for CRMP2 in neuronal plasticity, neural function and behavioural modulation in mice.
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Affiliation(s)
- Hongsheng Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Eunchai Kang
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Yaqing Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Chaojuan Yang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Hui Yu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Qin Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zheyu Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Shandong University, Jinan, Shandong 250012, China
| | - Chen Zhang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, College of Life Sciences, Peking University, Beijing 100871, China
| | - Kimberly M. Christian
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Hongjun Song
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Guo-li Ming
- Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Psychiatry and Behavioral Science, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Zhiheng Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Translational Medical Center for Stem Cell Therapy, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, China
- Parkinson’s Disease Center, Beijing Institute for Brain Disorders, Beijing 100871, China
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85
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Kennedy BC, Dimova JG, Dakoji S, Yuan LL, Gewirtz JC, Tran PV. Deletion of novel protein TMEM35 alters stress-related functions and impairs long-term memory in mice. Am J Physiol Regul Integr Comp Physiol 2016; 311:R166-78. [PMID: 27170659 DOI: 10.1152/ajpregu.00066.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/04/2016] [Indexed: 12/20/2022]
Abstract
The mounting of appropriate emotional and neuroendocrine responses to environmental stressors critically depends on the hypothalamic-pituitary-adrenal (HPA) axis and associated limbic circuitry. Although its function is currently unknown, the highly evolutionarily conserved transmembrane protein 35 (TMEM35) is prominently expressed in HPA circuitry and limbic areas, including the hippocampus and amygdala. To investigate the possible involvement of this protein in neuroendocrine function, we generated tmem35 knockout (KO) mice to characterize the endocrine, behavioral, electrophysiological, and proteomic alterations caused by deletion of the tmem35 gene. While capable of mounting a normal corticosterone response to restraint stress, KO mice showed elevated basal corticosterone accompanied by increased anxiety-like behavior. The KO mice also displayed impairment of hippocampus-dependent fear and spatial memories. Given the intact memory acquisition but a deficit in memory retention in the KO mice, TMEM35 is likely required for long-term memory consolidation. This conclusion is further supported by a loss of long-term potentiation in the Schaffer collateral-CA1 pathway in the KO mice. To identify putative molecular pathways underlying alterations in plasticity, proteomic analysis of synaptosomal proteins revealed lower levels of postsynaptic molecules important for synaptic plasticity in the KO hippocampus, including PSD95 and N-methyl-d-aspartate receptors. Pathway analysis (Ingenuity Pathway Analysis) of differentially expressed synaptic proteins in tmem35 KO hippocampus implicated molecular networks associated with specific cellular and behavioral functions, including decreased long-term potentiation, and increased startle reactivity and locomotion. Collectively, these data suggest that TMEM35 is a novel factor required for normal activity of the HPA axis and limbic circuitry.
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Affiliation(s)
- Bruce C Kennedy
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota; Center for Neurobehavioral Development, University of Minnesota, Minneapolis, Minnesota
| | - Jiva G Dimova
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota
| | - Srikanth Dakoji
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota; and
| | - Li-Lian Yuan
- Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota
| | - Jonathan C Gewirtz
- Department of Psychology, University of Minnesota, Minneapolis, Minnesota; Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota; Center for Neurobehavioral Development, University of Minnesota, Minneapolis, Minnesota
| | - Phu V Tran
- Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota; and Center for Neurobehavioral Development, University of Minnesota, Minneapolis, Minnesota
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86
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Zhang Q, Goto H, Akiyoshi-Nishimura S, Prosselkov P, Sano C, Matsukawa H, Yaguchi K, Nakashiba T, Itohara S. Diversification of behavior and postsynaptic properties by netrin-G presynaptic adhesion family proteins. Mol Brain 2016; 9:6. [PMID: 26746425 PMCID: PMC4706652 DOI: 10.1186/s13041-016-0187-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/04/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Vertebrate-specific neuronal genes are expected to play a critical role in the diversification and evolution of higher brain functions. Among them, the glycosylphosphatidylinositol (GPI)-anchored netrin-G subfamily members in the UNC6/netrin family are unique in their differential expression patterns in many neuronal circuits, and differential binding ability to their cognate homologous post-synaptic receptors. RESULTS To gain insight into the roles of these genes in higher brain functions, we performed comprehensive behavioral batteries using netrin-G knockout mice. We found that two netrin-G paralogs that recently diverged in evolution, netrin-G1 and netrin-G2 (gene symbols: Ntng1 and Ntng2, respectively), were responsible for complementary behavioral functions. Netrin-G2, but not netrin-G1, encoded demanding sensorimotor functions. Both paralogs were responsible for complex vertebrate-specific cognitive functions and fine-scale regulation of basic adaptive behaviors conserved between invertebrates and vertebrates, such as spatial reference and working memory, attention, impulsivity and anxiety etc. Remarkably, netrin-G1 and netrin-G2 encoded a genetic "division of labor" in behavioral regulation, selectively mediating different tasks or even different details of the same task. At the cellular level, netrin-G1 and netrin-G2 differentially regulated the sub-synaptic localization of their cognate receptors and differentiated the properties of postsynaptic scaffold proteins in complementary neural pathways. CONCLUSIONS Pre-synaptic netrin-G1 and netrin-G2 diversify the complexity of vertebrate behaviors and differentially regulate post-synaptic properties. Our findings constitute the first genetic analysis of the behavioral and synaptic diversification roles of a vertebrate GPI protein and presynaptic adhesion molecule family.
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Affiliation(s)
- Qi Zhang
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Hiromichi Goto
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Sachiko Akiyoshi-Nishimura
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Pavel Prosselkov
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Chie Sano
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Hiroshi Matsukawa
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Kunio Yaguchi
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Toshiaki Nakashiba
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
| | - Shigeyoshi Itohara
- Laboratory for Behavioral Genetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan.
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87
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Status Epilepticus Enhances Depotentiation after Fully Established LTP in an NMDAR-Dependent but GluN2B-Independent Manner. Neural Plast 2016; 2016:6592038. [PMID: 26881126 PMCID: PMC4735914 DOI: 10.1155/2016/6592038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/26/2015] [Accepted: 11/01/2015] [Indexed: 11/22/2022] Open
Abstract
N-Methyl-D-aspartate (NMDA) receptor-dependent long-term potentiation (LTP) can be reversed by low-frequency stimulation (LFS) referred to as depotentiation (DP). We previously found GluN2B upregulated in CA1 neurons from post-status epilepticus (post-SE) tissue associated with an enhanced LTP. Here, we tested whether LFS-induced DP is also altered in pathological GluN2B upregulation. Although LTP was enhanced in post-SE tissue, LTP was significantly reversed in this tissue, but not in controls. We next tested the effect of the GluN2B subunit-specific blocker Ro 25-6981 (1 μM) on LFS-DP. As expected, LFS had no effect on synaptic strength in the presence of the GluN2B blocker in control tissue. In marked contrast, LFS-DP was also attained in post-SE tissue indicating that GluN2B was obviously not involved in depotentiation. To test for NMDA receptor-dependence, we applied the NMDA receptor antagonist D-AP5 (50 μM) prior to LFS and observed that DP was abolished in both control and post-SE tissue confirming NMDA receptor involvement. These results indicate that control Schaffer collateral-CA1 synapses cannot be depotentiated after fully established LTP, but LFS was able to reverse LTP significantly in post-SE tissue. However, while LFS-DP clearly required NMDA receptor activation, GluN2B-containing NMDA receptors were not involved in this form of depotentiation.
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88
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Lo FS, Erzurumlu RS. Neonatal sensory nerve injury-induced synaptic plasticity in the trigeminal principal sensory nucleus. Exp Neurol 2016; 275 Pt 2:245-52. [PMID: 25956829 PMCID: PMC4636484 DOI: 10.1016/j.expneurol.2015.04.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 04/29/2015] [Indexed: 11/26/2022]
Abstract
Sensory deprivation studies in neonatal mammals, such as monocular eye closure, whisker trimming, and chemical blockade of the olfactory epithelium have revealed the importance of sensory inputs in brain wiring during distinct critical periods. But very few studies have paid attention to the effects of neonatal peripheral sensory nerve damage on synaptic wiring of the central nervous system (CNS) circuits. Peripheral somatosensory nerves differ from other special sensory afferents in that they are more prone to crush or severance because of their locations in the body. Unlike the visual and auditory afferents, these nerves show regenerative capabilities after damage. Uniquely, damage to a somatosensory peripheral nerve does not only block activity incoming from the sensory receptors but also mediates injury-induced neuro- and glial chemical signals to the brain through the uninjured central axons of the primary sensory neurons. These chemical signals can have both far more and longer lasting effects than sensory blockade alone. Here we review studies which focus on the consequences of neonatal peripheral sensory nerve damage in the principal sensory nucleus of the brainstem trigeminal complex.
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Affiliation(s)
- Fu-Sun Lo
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA.
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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89
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Thompson SM, Josey M, Holmes A, Brigman JL. Conditional loss of GluN2B in cortex and hippocampus impairs attentional set formation. Behav Neurosci 2015; 129:105-12. [PMID: 25798630 DOI: 10.1037/bne0000045] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The ability to attend to appropriate stimuli, to plan actions and then alter those actions when environmental conditions change, is essential for an organism to thrive. There is increasing evidence that these executive control processes are mediated in part by N-methyl-D-aspartate receptors (NMDAR). NMDAR subunits confer different physiological properties to the receptor, interact with distinct intracellular postsynaptic scaffolding and signaling molecules and are differentially expressed during development. Recent findings have suggested that the GluN2B subunit may play a unique role in both the acquisition of adaptive choice and the behavioral flexibility required to shift between choices. Here we investigated the role of GluN2B containing NMDARs in the ability to learn, reverse and shift between stimulus dimensions. Mutant mice (floxed-GluN2B x CaMKII-Cre) lacking GluN2B in the dorsal CA1 of the hippocampus and throughout the cortex were tested on an attentional set-shifting task. To explore the role that alterations in motor behavior may have on these behaviors, gross and fine motor behaviors were analyzed in mutant and floxed-control mice. Results show that corticohippocampal loss of GluN2B selectively impaired an initial reversal in a stimulus specific manner and impaired the ability of mutant mice to form an attentional set. Further, GluN2B mice showed normal motor behavior in both overall movement and individual limb behaviors. Together, these results further support the role of NMDAR, and GluN2B in particular, in aspects of executive control including behavioral flexibility and attentional processes.
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Affiliation(s)
- Shannon M Thompson
- Department of Neurosciences, University of New Mexico School of Medicine
| | - Megan Josey
- Department of Neurosciences, University of New Mexico School of Medicine
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institutes of Health
| | - Jonathan L Brigman
- Department of Neurosciences, University of New Mexico School of Medicine
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90
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Vieira MM, Schmidt J, Ferreira JS, She K, Oku S, Mele M, Santos AE, Duarte CB, Craig AM, Carvalho AL. Multiple domains in the C-terminus of NMDA receptor GluN2B subunit contribute to neuronal death following in vitro ischemia. Neurobiol Dis 2015; 89:223-34. [PMID: 26581639 DOI: 10.1016/j.nbd.2015.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 10/23/2015] [Accepted: 11/11/2015] [Indexed: 11/16/2022] Open
Abstract
Global cerebral ischemia induces selective degeneration of specific subsets of neurons throughout the brain, particularly in the hippocampus and cortex. One of the major hallmarks of cerebral ischemia is excitotoxicity, characterized by overactivation of glutamate receptors leading to intracellular Ca(2+) overload and ultimately neuronal demise. N-methyl-d-aspartate receptors (NMDARs) are considered to be largely responsible for excitotoxic injury due to their high Ca(2+) permeability. In the hippocampus and cortex, these receptors are most prominently composed of combinations of two GluN1 subunits and two GluN2A and/or GluN2B subunits. Due to the controversy regarding the differential role of GluN2A and GluN2B subunits in excitotoxic cell death, we investigated the role of GluN2B in the activation of pro-death signaling following an in vitro model of global ischemia, oxygen and glucose deprivation (OGD). For this purpose, we used GluN2B(-/-) mouse cortical cultures and observed that OGD-induced damage was reduced in these neurons, and partially prevented in wild-type rat neurons by a selective GluN2B antagonist. Notably, we found a crucial role of the C-terminal domain of the GluN2B subunit in triggering excitotoxic signaling. Indeed, expression of YFP-GluN2B C-terminus mutants for the binding sites to post-synaptic density protein 95 (PSD95), Ca(2+)-calmodulin kinase IIα (CaMKIIα) or clathrin adaptor protein 2 (AP2) failed to mediate neuronal death in OGD conditions. We focused on the GluN2B-CaMKIIα interaction and found a determinant role of this interaction in OGD-induced death. Inhibition or knock-down of CaMKIIα exerted a neuroprotective effect against OGD-induced death, whereas overexpression of this kinase had a detrimental effect. Importantly, in comparison with neurons overexpressing wild-type CaMKIIα, neurons overexpressing a mutant form of the kinase (CaMKII-I205K), unable to interact with GluN2B, were partially protected against OGD-induced damage. Taken together, our results identify crucial determinants in the C-terminal domain of GluN2B subunits in promoting neuronal death in ischemic conditions. These mechanisms underlie the divergent roles of the GluN2A- and GluN2B-NMDARs in determining neuronal fate in cerebral ischemia.
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Affiliation(s)
- Marta M Vieira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Jeannette Schmidt
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; PDBEB - Doctoral Program in Experimental Biology and Biomedicine, Center for Neuroscience and Cell Biology, Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Joana S Ferreira
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Kevin She
- Brain Research Centre and Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
| | - Shinichiro Oku
- Brain Research Centre and Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
| | - Miranda Mele
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Armanda E Santos
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Carlos B Duarte
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ann Marie Craig
- Brain Research Centre and Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
| | - Ana Luísa Carvalho
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal; Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
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91
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Grados M, Prazak M, Saif A, Halls A. A review of animal models of obsessive-compulsive disorder: a focus on developmental, immune, endocrine and behavioral models. Expert Opin Drug Discov 2015; 11:27-43. [PMID: 26558411 DOI: 10.1517/17460441.2016.1103225] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Obsessive-compulsive disorder (OCD) is a neuropsychiatric condition characterized by intrusive thoughts (obsessions) and/or repetitive behaviors (compulsions). Several models of OCD exist, many which employ behaviors such as over-grooming or hoarding as correlates for compulsive behaviors - often using a response to serotonergic agents as evidence for their validity. Recent discoveries in the genetics of OCD and the identification of aberrancies of glutamatergic, hormonal, and immune pathways in the OCD phenotype highlight a need to review existing of animal models of OCD. The focus of attention to these pathways may lead to possible new targets for drug discovery. AREAS COVERED In this review, the authors describe frameworks for animal models in OCD conceptualized as either biological (e.g., developmental, genetic, and endocrine pathways), or behavioral (e.g., repetitive grooming, and stereotypies). In addition, the authors give special attention to the emerging role of glutamate in OCD. EXPERT OPINION While many animal models for OCD demonstrate pathologic repetitive behavior phenotypes, which are relieved by serotoninergic agents, animal models based on reversal learning, perseverative responding, and neurodevelopmental mechanisms represent robust new paradigms. Glutamatergic influences in these new animal models suggest that drug discovery using neuroprotective approaches may represent a new stage for pharmacologic developments in OCD.
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Affiliation(s)
- Marco Grados
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
| | - Michael Prazak
- b Department of Medicine , Dow University of Health Sciences , Karachi , Pakistan
| | - Aneeqa Saif
- c Department of Psychology Grand Forks , University of North Dakota , ND , USA
| | - Andrew Halls
- a Department of Psychiatry , Johns Hopkins University , 1800 Orleans St. - 12th floor, Baltimore , MD 21287 , USA
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92
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Molecular and anatomical evidence for the input pathway- and target cell type-dependent regulation of glutamatergic synapses. Anat Sci Int 2015; 91:8-21. [DOI: 10.1007/s12565-015-0303-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/17/2015] [Indexed: 10/23/2022]
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93
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Üner A, Gonçalves GH, Li W, Porceban M, Caron N, Schönke M, Delpire E, Sakimura K, Bjørbæk C. The role of GluN2A and GluN2B NMDA receptor subunits in AgRP and POMC neurons on body weight and glucose homeostasis. Mol Metab 2015; 4:678-91. [PMID: 26500840 PMCID: PMC4588453 DOI: 10.1016/j.molmet.2015.06.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 06/15/2015] [Accepted: 06/19/2015] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE Hypothalamic agouti-related peptide (AgRP) and pro-opiomelanocortin (POMC) expressing neurons play critical roles in control of energy balance. Glutamatergic input via n-methyl-d-aspartate receptors (NMDARs) is pivotal for regulation of neuronal activity and is required in AgRP neurons for normal body weight homeostasis. NMDARs typically consist of the obligatory GluN1 subunit and different GluN2 subunits, the latter exerting crucial differential effects on channel activity and neuronal function. Currently, the role of specific GluN2 subunits in AgRP and POMC neurons on whole body energy and glucose balance is unknown. METHODS We used the cre-lox system to genetically delete GluN2A or GluN2B only from AgRP or POMC neurons in mice. Mice were then subjected to metabolic analyses and assessment of AgRP and POMC neuronal function through morphological studies. RESULTS We show that loss of GluN2B from AgRP neurons reduces body weight, fat mass, and food intake, whereas GluN2B in POMC neurons is not required for normal energy balance control. GluN2A subunits in either AgRP or POMC neurons are not required for regulation of body weight. Deletion of GluN2B reduces the number of AgRP neurons and decreases their dendritic length. In addition, loss of GluN2B in AgRP neurons of the morbidly obese and severely diabetic leptin-deficient Lep (ob/ob) mice does not affect body weight and food intake but, remarkably, leads to full correction of hyperglycemia. Lep (ob/ob) mice lacking GluN2B in AgRP neurons are also more sensitive to leptin's anti-obesity actions. CONCLUSIONS GluN2B-containing NMDA receptors in AgRP neurons play a critical role in central control of body weight homeostasis and blood glucose balance via mechanisms that likely involve regulation of AgRP neuronal survival and structure, and modulation of hypothalamic leptin action.
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Key Words
- AAC, area above the curve
- AMPARs, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors
- ANCOVA, analysis of covariance
- ANOVA, analysis of variance
- AUC, area under the curve
- AgRP
- AgRP, agouti-related peptide
- CNS, central nervous system
- DAB, 3,3′-diaminobenzidine
- DIO, diet-induced obesity
- DREADD, Designer Receptor Exclusively Activated by Dedigner Drugs
- EPSCs, excitatory post-synaptic synaptic currents
- GABA, gamma-aminobutyric acid
- GTT, glucose tolerance test
- GluN2B
- Glycemia
- HFD, high-fat diet
- HSD, honestly significant difference
- ITT, insulin tolerance test
- KO, knockout
- LTD, long-term depression
- LTP, long-term potentiation
- Lepob/ob mice, obese leptin-deficient mice
- Leptin
- Metabolism
- NMDAR
- NMDARs, N-methyl-d-aspartate receptors
- PBS, phosphate-buffered saline
- POMC, pro-opiomelanocortin
- PVN, paraventricular nucleus
- RT, room temperature
- hrGFP, humanized renilla GFP
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Affiliation(s)
- Aykut Üner
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Gabriel H.M. Gonçalves
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Wenjing Li
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Matheus Porceban
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Nicole Caron
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Milena Schönke
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University Medical School, Nashville, TN 37232, USA
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Christian Bjørbæk
- Department of Medicine, Division of Endocrinology and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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94
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GluN2B-Containing NMDA Receptors Regulate AMPA Receptor Traffic through Anchoring of the Synaptic Proteasome. J Neurosci 2015; 35:8462-79. [PMID: 26041915 DOI: 10.1523/jneurosci.3567-14.2015] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
NMDA receptors play a central role in shaping the strength of synaptic connections throughout development and in mediating synaptic plasticity mechanisms that underlie some forms of learning and memory formation in the CNS. In the hippocampus and the neocortex, GluN1 is combined primarily with GluN2A and GluN2B, which are differentially expressed during development and confer distinct molecular and physiological properties to NMDA receptors. The contribution of each subunit to the synaptic traffic of NMDA receptors and therefore to their role during development and in synaptic plasticity is still controversial. We report a critical role for the GluN2B subunit in regulating NMDA receptor synaptic targeting. In the absence of GluN2B, the synaptic levels of AMPA receptors are increased and accompanied by decreased constitutive endocytosis of GluA1-AMPA receptor. We used quantitative proteomic analysis to identify changes in the composition of postsynaptic densities from GluN2B(-/-) mouse primary neuronal cultures and found altered levels of several ubiquitin proteasome system components, in particular decreased levels of proteasome subunits. Enhancing the proteasome activity with a novel proteasome activator restored the synaptic levels of AMPA receptors in GluN2B(-/-) neurons and their endocytosis, revealing that GluN2B-mediated anchoring of the synaptic proteasome is responsible for fine tuning AMPA receptor synaptic levels under basal conditions.
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95
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Liu H, Li Y, Wang Y, Wang X, An X, Wang S, Chen L, Liu G, Yang Y. The distinct role of NR2B subunit in the enhancement of visual plasticity in adulthood. Mol Brain 2015; 8:49. [PMID: 26282667 PMCID: PMC4539718 DOI: 10.1186/s13041-015-0141-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/10/2015] [Indexed: 01/23/2023] Open
Abstract
Background Experience-dependent plasticity is confined to the critical period of early postnatal life, and declines dramatically thereafter. This attenuation promotes the stabilization of cortical circuits, but also limits functional recovery of several brain diseases. The cognitive functions and synaptic plasticity in the hippocampus and prefrontal cortex are elevated following chronic magnesium treatment. Here, we explored the effect of magnesium treatment on visual plasticity and the potential clinical significance. Results Visual plasticity in adult mice was dramatically enhanced following magnesium treatment, which was concurrent with an increase in the expression of NR2 subunits of N-methyl-D-aspartate receptors. Blockade of NR2B activity in both the induction and expression periods of plasticity prevented this reinstatement. However, the plasticity restored via a decrease in cortical inhibition was independent on the activation of NR2B, indicating a different underlying mechanism. The functional excitatory synapses on layer 2/3 pyramidal neurons were increased following magnesium supplementation. Moreover, the synaptic and neuronal responses were reminiscent of that within the critical period, and this rejuvenation of adult visual cortex facilitated the recovery of visual functions in amblyopia. Conclusions Collectively, our data reveal two distinct mechanisms underlying the restoration of visual plasticity in adulthood, and the rejuvenation of adult visual cortex following magnesium treatment provides a new avenue to develop clinical therapies for adult amblyopia, as well as to explore plasticity-based treatment of other brain diseases, such as stroke and aphasia. Electronic supplementary material The online version of this article (doi:10.1186/s13041-015-0141-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hanxiao Liu
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230027, China
| | - Yue Li
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China
| | - Yan Wang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China
| | - Xinxing Wang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China
| | - Xu An
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China
| | - Siying Wang
- School of Basic Medicine, Anhui Medical University, Hefei, 230032, China
| | - Lin Chen
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei, 230027, China
| | - Guosong Liu
- Tsinghua-Peking Centre for Life Sciences, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Yupeng Yang
- Chinese Academy of Sciences Key Laboratory of Brain Function and Diseases, and School of Life Sciences, University of Science and Technology of China, Hefei, 230027, China.
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96
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Yokota S, Sato A, Umezawa M, Oshio S, Takeda K. In utero exposure of mice to diesel exhaust particles affects spatial learning and memory with reduced N-methyl-D-aspartate receptor expression in the hippocampus of male offspring. Neurotoxicology 2015; 50:108-15. [PMID: 26291742 DOI: 10.1016/j.neuro.2015.08.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 10/23/2022]
Abstract
Diesel exhaust consists of diesel exhaust particles (DEPs) and gaseous compounds. Previous studies reported that in utero exposure to diesel exhaust affects the central nervous system. However, there was no clear evidence that these effects were caused by diesel exhaust particles themselves, gaseous compounds, or both. Here, we explored the effects of in utero exposure to DEPs on learning and memory in male ICR mice. DEP solutions were administered subcutaneously to pregnant ICR mice at a dose of 0 or 200 μg/kg body weight on gestation days 6, 9, 12, 15, and 18. We examined learning and memory in 9-to-10-week-old male offspring using the Morris water maze test and passive avoidance test. Immediately after the behavioral tests, hippocampi were isolated. Hippocampal N-methyl-D-aspartate receptor (NR) expression was also measured by quantitative RT-PCR analysis. Mice exposed to DEPs in utero showed deficits in the Morris water maze test, but their performance was not significantly different from that of control mice in the passive avoidance test. In addition, DEP-exposed mice exhibited decreased hippocampal NR2A expression. The present results indicate that maternal DEP exposure disrupts learning and memory in male offspring, which is associated with reduced hippocampal NR2A expression.
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Affiliation(s)
- Satoshi Yokota
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan; Department of Hygiene Chemistry, School of Pharmaceutical Sciences, Ohu University, 31-3 Misumido, Tomita, Koriyama, Fukushima 963-8611, Japan.
| | - Akira Sato
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
| | - Masakazu Umezawa
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
| | - Shigeru Oshio
- Department of Hygiene Chemistry, School of Pharmaceutical Sciences, Ohu University, 31-3 Misumido, Tomita, Koriyama, Fukushima 963-8611, Japan.
| | - Ken Takeda
- The Center for Environmental Health Science for the Next Generation, Research Institute for Science and Technology, Organization for Research Advancement, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan.
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97
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Ahmari SE, Dougherty DD. DISSECTING OCD CIRCUITS: FROM ANIMAL MODELS TO TARGETED TREATMENTS. Depress Anxiety 2015; 32:550-62. [PMID: 25952989 PMCID: PMC4515165 DOI: 10.1002/da.22367] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 02/18/2015] [Accepted: 02/28/2015] [Indexed: 01/08/2023] Open
Abstract
Obsessive-compulsive disorder (OCD) is a chronic, severe mental illness with up to 2-3% prevalence worldwide. In fact, OCD has been classified as one of the world's 10 leading causes of illness-related disability according to the World Health Organization, largely because of the chronic nature of disabling symptoms.([1]) Despite the severity and high prevalence of this chronic and disabling disorder, there is still relatively limited understanding of its pathophysiology. However, this is now rapidly changing due to development of powerful technologies that can be used to dissect the neural circuits underlying pathologic behaviors. In this article, we describe recent technical advances that have allowed neuroscientists to start identifying the circuits underlying complex repetitive behaviors using animal model systems. In addition, we review current surgical and stimulation-based treatments for OCD that target circuit dysfunction. Finally, we discuss how findings from animal models may be applied in the clinical arena to help inform and refine targeted brain stimulation-based treatment approaches.
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Affiliation(s)
- Susanne E. Ahmari
- Translational Neuroscience Program, Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, 15219 USA
| | - Darin D. Dougherty
- Department of Psychiatry, Massachusetts General Hospital, Boston, MA, 02114, USA
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98
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Ogden KK, Ozkan ED, Rumbaugh G. Prioritizing the development of mouse models for childhood brain disorders. Neuropharmacology 2015; 100:2-16. [PMID: 26231830 DOI: 10.1016/j.neuropharm.2015.07.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 07/18/2015] [Accepted: 07/22/2015] [Indexed: 12/20/2022]
Abstract
Mutations in hundreds of genes contribute to cognitive and behavioral dysfunction associated with developmental brain disorders (DBDs). Due to the sheer number of risk factors available for study combined with the cost of developing new animal models, it remains an open question how genes should be prioritized for in-depth neurobiological investigations. Recent reviews have argued that priority should be given to frequently mutated genes commonly found in sporadic DBD patients. Intrigued by this idea, we explored to what extent "high priority" risk factors have been studied in animals in an effort to assess their potential for generating valuable preclinical models capable of advancing the neurobiological understanding of DBDs. We found that in-depth whole animal studies are lacking for many high priority genes, with relatively few neurobiological studies performed in construct valid animal models aimed at understanding the pathological substrates associated with disease phenotypes. However, some high priority risk factors have been extensively studied in animal models and they have generated novel insights into DBD patho-neurobiology while also advancing early pre-clinical therapeutic treatment strategies. We suggest that prioritizing model development toward genes frequently mutated in non-specific DBD populations will accelerate the understanding of DBD patho-neurobiology and drive novel therapeutic strategies. This article is part of the Special Issue entitled 'Synaptopathy--from Biology to Therapy'.
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Affiliation(s)
- Kevin K Ogden
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Emin D Ozkan
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Gavin Rumbaugh
- Department of Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
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99
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Jacobs S, Wei W, Wang D, Tsien JZ. Importance of the GluN2B carboxy-terminal domain for enhancement of social memories. ACTA ACUST UNITED AC 2015; 22:401-10. [PMID: 26179233 PMCID: PMC4509920 DOI: 10.1101/lm.038521.115] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 06/09/2015] [Indexed: 12/18/2022]
Abstract
The N-methyl-D-aspartate (NMDA) receptor is known to be necessary for many forms of learning and memory, including social recognition memory. Additionally, the GluN2 subunits are known to modulate multiple forms of memory, with a high GluN2A:GluN2B ratio leading to impairments in long-term memory, while a low GluN2A:GluN2B ratio enhances some forms of long-term memory. Here, we investigate the molecular motif responsible for the differences in social recognition memory and olfactory memory in the forebrain-specific transgenic GluN2A overexpression mice and the forebrain-specific transgenic GluN2B overexpression mice by using two transgenic mouse lines that overexpress chimeric GluN2 subunits. The transgenic chimeric GluN2 subunit mice were tested for their ability to learn and remember fruit scents, male juveniles of the same strain, females of the same strain, male juveniles of another strain, and rodents of another species. The data presented here demonstrate that the GluN2B carboxy-terminal domain is necessary for enhanced social recognition memory in GluN2B transgenic overexpression mice. Furthermore, the GluN2A carboxy-terminal domain is responsible for the impaired long-term olfactory and social memory observed in the GluN2A overexpression mice.
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Affiliation(s)
- Stephanie Jacobs
- Department of Neurology, Brain and Behavior Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30907, USA
| | - Wei Wei
- Banna Biomedical Research Institute, Xi-Shuang-Ban-Na Prefecture, Yunnan Province, 666100, China
| | - Deheng Wang
- Banna Biomedical Research Institute, Xi-Shuang-Ban-Na Prefecture, Yunnan Province, 666100, China
| | - Joe Z Tsien
- Department of Neurology, Brain and Behavior Discovery Institute, Medical College of Georgia, Georgia Regents University, Augusta, Georgia 30907, USA
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100
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Yasuda H, Mukai H. Turning off of GluN2B subunits and turning on of CICR in hippocampal LTD induction after developmental GluN2 subunit switch. Hippocampus 2015; 25:1274-84. [PMID: 25727316 DOI: 10.1002/hipo.22435] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2015] [Indexed: 11/08/2022]
Abstract
NMDA receptors (NMDARs) are essential for the induction of synaptic plasticity that mediates activity-dependent refinement of neural circuits during development. GluN2B subunits of NMDARs are abundant at synapses in the immature hippocampus and begin to be replaced by GluN2A subunits with the help of casein kinase 2 activity in the second postnatal week, the critical period for the GluN2 subunit switch (Sanz-Clemente et al. (2000) Neuron 67:984-996). However, the physiological role of GluN2B subunits in the hippocampus during this critical period has not been elucidated. Here, we report that GluN2B subunits mediate the induction of long-term depression (LTD) in the CA1 region of the hippocampus only until this period. Ifenprodil and Ro25-6981, selective inhibitors of NMDARs containing GluN2B subunits, blocked LTD in postnatal Day 11-14 (P11-14) rat hippocampal slices but not in P18-22 hippocampus. Just a few days after P14, synaptic NMDAR currents became narrower than those at P11-14, and calcium influx through NMDARs must be reduced. We found that calcium-induced calcium release (CICR) through ryanodine receptors starts to support the induction of NMDAR-dependent LTD at P18-22. Intracellular application of thapsigargin and ryanodine, inhibitors of Ca2+ -ATP pumps on internal stores and ryanodine receptors, respectively, did not at all affect LTD in the hippocampus at P11-14 but completely blocked LTD in the P18-22 hippocampus. Therefore, calcium influx through NMDAR with GluN2B subunits is sufficient to induce LTD at P11-14, after which CICR compensates for the decrease in calcium influx during LTD induction.
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Affiliation(s)
- Hiroki Yasuda
- Education and Research Support Center, Gunma University Graduate School of Medicine, Maebashi, Japan
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