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Lee M, Kim EJ, Yum MS. Early developmental changes in a rat model of malformations of cortical development: Abnormal neuronal migration and altered response to NMDA-induced excitotoxic injury. Exp Neurol 2024; 376:114759. [PMID: 38519010 DOI: 10.1016/j.expneurol.2024.114759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 02/28/2024] [Accepted: 03/18/2024] [Indexed: 03/24/2024]
Abstract
Malformations of cortical development (MCDs) are caused by abnormal neuronal migration processes during the fetal period and are a major cause of intractable epilepsy in infancy. However, the timing of hyperexcitability or epileptogenesis in MCDs remains unclear. To identify the early developmental changes in the brain of the MCD rat model, which exhibits increased seizure susceptibility during infancy (P12-15), we analyzed the pathological changes in the brains of MCD model rats during the neonatal period and tested NMDA-induced seizure susceptibility. Pregnant rats were injected with two doses of methylazoxymethanol acetate (MAM, 15 mg/kg, i.p.) to induce MCD, while controls were administered normal saline. The cortical development of the offspring was measured by performing magnetic resonance imaging (MRI) on postnatal days (P) 1, 5, and 8. At P8, some rats were sacrificed for immunofluorescence, Golgi staining, and Western analysis. In another set of rats, the number and latency to onset of spasms were monitored for 90 min after the NMDA (5 mg/kg i.p.) injection at P8. In MCD rats, in vivo MR imaging showed smaller brain volume and thinner cortex from day 1 after birth (p < 0.001). Golgi staining and immunofluorescence revealed abnormal neuronal migration, with a reduced number of neuronal cell populations and less dendritic arborization at P8. Furthermore, MCD rats exhibited a significant reduction in the expression of NMDA receptors and AMPAR4, along with an increase in AMPAR3 expression (p < 0.05). Although there was no difference in the latency to seizure onset between MCD rats and controls, the MCD rats survived significantly longer than the controls. These results provide insights into the early developmental changes in the cortex of a MCD rat model and suggest that delayed and abnormal neuronal development in the immature brain is associated with a blunted response to NMDA-induced excitotoxic injury. These developmental changes may be involved in the sudden onset of epilepsy in patients with MCD or prenatal brain injury.
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Affiliation(s)
- Minyoung Lee
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea; Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Republic of Korea.
| | - Eun-Jin Kim
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea; Asan Institute for Life Sciences, Asan Medical Center, Seoul 05505, Republic of Korea
| | - Mi-Sun Yum
- Department of Pediatrics, University of Ulsan College of Medicine, Seoul 05505, Republic of Korea; Department of Pediatrics, Asan Medical Center Children's Hospital, Seoul 05505, Republic of Korea.
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2
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Chen T, Zhu J, Wang YH. RNF216 mediates neuronal injury following experimental subarachnoid hemorrhage through the Arc/Arg3.1-AMPAR pathway. FASEB J 2020; 34:15080-15092. [PMID: 32918771 DOI: 10.1096/fj.201903151rrrr] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 08/21/2020] [Accepted: 08/31/2020] [Indexed: 12/13/2022]
Abstract
Subarachnoid hemorrhage (SAH), mostly caused by aneurysm rupture, is a pathological condition associated with oxidative stress and neuroinflammation. Toll-like receptors (TLRs) are a family of key regulators of neuroinflammation, and RNF216 is an E3 ubiquitin-protein ligase that regulates TLRs via ubiquitination and proteolytic degradation. However, the role of RNF216 in SAH has not been determined. In this study, we investigated the biological function of RNF216 in experimental SAH models both in vitro and in vivo. The expression of RNF216 was found to be upregulated in cortical neurons after oxyhemoglobin (OxyHb) treatment, and increased RNF216 expression was also observed in brain tissues in the single-hemorrhage model of SAH. Downregulation of RNF216 expression by short interfering RNA (siRNA) transfection significantly reduced cytotoxicity and apoptosis after OxyHb exposure. The results of western blot showed that the RNF216-mediated neuronal injury in vitro was associated with the regulation of the Arc-AMPAR pathway, which was related to intracellular Ca2+ dysfunction, as evidenced by Ca2+ imaging. In addition, knockdown of RNF216 in vivo using intraventricular injection of siRNA was found to attenuate brain injury and neuroinflammation via the Arc-AMPAR pathway after SAH in the animal model. In summary, we demonstrated that silence of RNF216 expression protects against neuronal injury and neurological dysfunction in experimental SAH models. These data support for the first time that RNF216 may represent a novel candidate for therapies against SAH.
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Affiliation(s)
- Tao Chen
- Department of Neurosurgery, The 904th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, China
| | - Jie Zhu
- Department of Neurosurgery, The 904th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, China
| | - Yu-Hai Wang
- Department of Neurosurgery, The 904th Hospital of PLA, Medical School of Anhui Medical University, Wuxi, China
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Campelo T, Augusto E, Chenouard N, de Miranda A, Kouskoff V, Camus C, Choquet D, Gambino F. AMPAR-Dependent Synaptic Plasticity Initiates Cortical Remapping and Adaptive Behaviors during Sensory Experience. Cell Rep 2020; 32:108097. [PMID: 32877679 PMCID: PMC7487777 DOI: 10.1016/j.celrep.2020.108097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 11/28/2022] Open
Abstract
Cortical plasticity improves behaviors and helps recover lost functions after injury. However, the underlying synaptic mechanisms remain unclear. In mice, we show that trimming all but one whisker enhances sensory responses from the spared whisker in the barrel cortex and occludes whisker-mediated synaptic potentiation (w-Pot) in vivo. In addition, whisker-dependent behaviors that are initially impaired by single-whisker experience (SWE) rapidly recover when associated cortical regions remap. Cross-linking the surface GluA2 subunit of AMPA receptors (AMPARs) suppresses the expression of w-Pot, presumably by blocking AMPAR surface diffusion, in mice with all whiskers intact, indicating that synaptic potentiation in vivo requires AMPAR trafficking. We use this approach to demonstrate that w-Pot is required for SWE-mediated strengthening of synaptic inputs and initiates the recovery of previously learned skills during the early phases of SWE. Taken together, our data reveal that w-Pot mediates cortical remapping and behavioral improvement upon partial sensory deafferentation.
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Affiliation(s)
- Tiago Campelo
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Elisabete Augusto
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Nicolas Chenouard
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Aron de Miranda
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Vladimir Kouskoff
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Come Camus
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Daniel Choquet
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France; University of Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, 33000 Bordeaux, France.
| | - Frédéric Gambino
- University of Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France.
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Abstract
Purpose of review Stroke is a devastating illness which severely attenuates quality of life because of paralysis. Despite recent advances in therapies during acute phase such as thrombolytic therapy, clinical option to intervene the process of rehabilitation is limited. No pharmacological intervention that could enhance the effect of rehabilitation has not been established. Recent articles, which are summarized in the review article, reported novel small compound which accelerates training-dependent motor function recovery after brain damage. Recent findings A novel small compound, edonerpic maleate, binds to collapsin response mediator protein 2 (CRMP2) and enhance synaptic plasticity leading to the acceleration of rehabilitative training-dependent functional recovery after brain damage in rodent and nonhuman primate. The clinical trial to test this effect in human is now ongoing. Future preclinical and clinical studies will delineate the potentials of this compound. Summary A novel CRMP2-binding small compound, edonerpic maleate, accelerates motor function recovery after brain damage in rodent and nonhuman primate.
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Tada H, Miyazaki T, Takemoto K, Takase K, Jitsuki S, Nakajima W, Koide M, Yamamoto N, Komiya K, Suyama K, Sano A, Taguchi A, Takahashi T. Neonatal isolation augments social dominance by altering actin dynamics in the medial prefrontal cortex. Proc Natl Acad Sci U S A 2016; 113:E7097-E7105. [PMID: 27791080 PMCID: PMC5111648 DOI: 10.1073/pnas.1606351113] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Social separation early in life can lead to the development of impaired interpersonal relationships and profound social disorders. However, the underlying cellular and molecular mechanisms involved are largely unknown. Here, we found that isolation of neonatal rats induced glucocorticoid-dependent social dominance over nonisolated control rats in juveniles from the same litter. Furthermore, neonatal isolation inactivated the actin-depolymerizing factor (ADF)/cofilin in the juvenile medial prefrontal cortex (mPFC). Isolation-induced inactivation of ADF/cofilin increased stable actin fractions at dendritic spines in the juvenile mPFC, decreasing glutamate synaptic AMPA receptors. Expression of constitutively active ADF/cofilin in the mPFC rescued the effect of isolation on social dominance. Thus, neonatal isolation affects spines in the mPFC by reducing actin dynamics, leading to altered social behavior later in life.
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Affiliation(s)
- Hirobumi Tada
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Tomoyuki Miyazaki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kiwamu Takemoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, Saitama 332-0012, Japan
| | - Kenkichi Takase
- Laboratory of Psychology, Jichi Medical University, Tochigi 329-0498, Japan
| | - Susumu Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Waki Nakajima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Mayu Koide
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Naoko Yamamoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kasane Komiya
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kumiko Suyama
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Akane Sano
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Akiko Taguchi
- Department of Integrative Aging Neuroscience, National Center for Geriatrics and Gerontology, Aichi 474-8511, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan;
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Whitehead G, Regan P, Whitcomb DJ, Cho K. Ca 2+-permeable AMPA receptor: A new perspective on amyloid-beta mediated pathophysiology of Alzheimer's disease. Neuropharmacology 2016; 112:221-227. [PMID: 27561971 DOI: 10.1016/j.neuropharm.2016.08.022] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 08/17/2016] [Accepted: 08/18/2016] [Indexed: 12/24/2022]
Abstract
α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) are the primary conduits of excitatory synaptic transmission. AMPARs are predominantly Ca2+-impermeable in the matured excitatory synapse, except under certain circumstances. Growing evidence implicates the Ca2+ permeability of AMPARs in the regulation of long-term synaptic plasticity and in the pathophysiology of several neurological disorders. Therefore, the Ca2+ conductance of AMPARs may have both physiological and pathological roles at synapses. However, our understanding of the role of Ca2+ permeable AMPARs (CP-AMPARs) in Alzheimer's disease is limited. Here we discuss insights into the potential CP-AMPAR mediated pathophysiology of Alzheimer's disease, including: 1. Ca2+-mediated aberrant regulation of synapse weakening mechanisms, and 2. neuronal network dysfunction in the brain. Consideration of CP-AMPARs as primary drivers of pathophysiology could help in understanding synaptopathologies, and highlights the potential of CP-AMPARs as therapeutic targets in Alzheimer's disease. This article is part of the Special Issue entitled 'Ionotropic glutamate receptors'.
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Affiliation(s)
- Garry Whitehead
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (LINE), Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
| | - Philip Regan
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (LINE), Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
| | - Daniel J Whitcomb
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (LINE), Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK; Centre for Synaptic Plasticity, Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK
| | - Kwangwook Cho
- Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology (LINE), Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK; Centre for Synaptic Plasticity, Faculty of Health Sciences, University of Bristol, Whitson Street, Bristol BS1 3NY, UK.
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Nakajima W, Jitsuki S, Sano A, Takahashi T. Sustained Enhancement of Lateral Inhibitory Circuit Maintains Cross Modal Cortical Reorganization. PLoS One 2016; 11:e0149068. [PMID: 26863615 PMCID: PMC4749254 DOI: 10.1371/journal.pone.0149068] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 01/27/2016] [Indexed: 11/18/2022] Open
Abstract
Deprivation of one modality can lead to the improvement of other intact modalities. We have previously reported that visual deprivation drives AMPA receptors into synapses from layer4 to 2/3 in the barrel cortex and sharpens functional whisker-barrel map at layer2/3 2 days after the beginning of visual deprivation. Enhanced excitatory synaptic transmission at layer4-2/3 synapses is transient and returns to the base line level a week after the beginning of visual deprivation. Here we found that sharpened whisker-barrel function is maintained at least for a week in visually deprived animals. While increased AMPA receptor-mediated synaptic transmission at layer4-2/3 synapses dropped to the base line a week after the beginning of visual deprivation, lateral inhibitory synaptic transmission onto the neighboring barrel was kept strengthened for a week of visually deprived animals. Thus, transient strengthening of excitatory synapses at layer4-2/3 in the barrel cortex could trigger the enhancement of inhibitory inputs to neighboring barrel, and sustained lateral inhibition can maintain the sharpening of whisker-barrel map in visually deprived animals.
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Affiliation(s)
- Waki Nakajima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Susumu Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Akane Sano
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- * E-mail:
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8
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Jitsuki S, Nakajima W, Takemoto K, Sano A, Tada H, Takahashi-Jitsuki A, Takahashi T. Nogo Receptor Signaling Restricts Adult Neural Plasticity by Limiting Synaptic AMPA Receptor Delivery. Cereb Cortex 2015; 26:427-439. [PMID: 26472557 PMCID: PMC4677985 DOI: 10.1093/cercor/bhv232] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Experience-dependent plasticity is limited in the adult brain, and its molecular and cellular mechanisms are poorly understood. Removal of the myelin-inhibiting signaling protein, Nogo receptor (NgR1), restores adult neural plasticity. Here we found that, in NgR1-deficient mice, whisker experience-driven synaptic α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) insertion in the barrel cortex, which is normally complete by 2 weeks after birth, lasts into adulthood. In vivo live imaging by two-photon microscopy revealed more AMPAR on the surface of spines in the adult barrel cortex of NgR1-deficient than on those of wild-type (WT) mice. Furthermore, we observed that whisker stimulation produced new spines in the adult barrel cortex of mutant but not WT mice, and that the newly synthesized spines contained surface AMPAR. These results suggest that Nogo signaling limits plasticity by restricting synaptic AMPAR delivery in coordination with anatomical plasticity.
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Affiliation(s)
- Susumu Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Waki Nakajima
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kiwamu Takemoto
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan.,JST, PRESTO, Saitama 332-0012, Japan
| | - Akane Sano
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Hirobumi Tada
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Aoi Takahashi-Jitsuki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Takuya Takahashi
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
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9
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Estrous Cycle-Dependent Phasic Changes in the Stoichiometry of Hippocampal Synaptic AMPA Receptors in Rats. PLoS One 2015; 10:e0131359. [PMID: 26121335 PMCID: PMC4486186 DOI: 10.1371/journal.pone.0131359] [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: 01/15/2015] [Accepted: 06/01/2015] [Indexed: 11/26/2022] Open
Abstract
Cognitive function can be affected by the estrous cycle. However, the effect of the estrous cycle on synaptic functions is poorly understood. Here we show that in female rats, inhibitory-avoidance (IA) task (hippocampus-dependent contextual fear-learning task) drives GluA2-lacking Ca2+-permeable AMPA receptors (CP-AMPARs) into the hippocampal CA3-CA1 synapses during all periods of the estrous cycle except the proestrous period, when estrogen levels are high. In addition, IA task failed to drive CP-AMPARs into the CA3-CA1 synapses of ovariectomized rats only when estrogen was present. Thus, changes in the stoichiometry of AMPA receptors during learning depend on estrogen levels. Furthermore, the induction of long-term potentiation (LTP) after IA task was prevented during the proestrous period, while intact LTP is still expressed after IA task during other period of the estrous cycle. Consistent with this finding, rats conditioned by IA training failed to acquire hippocampus-dependent Y-maze task during the proestrous period. On the other hand, during other estrous period, rats were able to learn Y-maze task after IA conditioning. These results suggest that high estrogen levels prevent the IA learning-induced delivery of CP-AMPARs into hippocampal CA3-CA1 synapses and limit synaptic plasticity after IA task, thus preventing the acquisition of additional learning.
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Pandey SP, Rai R, Gaur P, Prasad S. Development- and age-related alterations in the expression of AMPA receptor subunit GluR2 and its trafficking proteins in the hippocampus of male mouse brain. Biogerontology 2015; 16:317-28. [DOI: 10.1007/s10522-014-9548-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
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Isoflurane impairs learning and hippocampal long-term potentiation via the saturation of synaptic plasticity. Anesthesiology 2014; 121:302-10. [PMID: 24758773 DOI: 10.1097/aln.0000000000000269] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND General anesthesia induces long-lasting cognitive and learning deficits. However, the underlying mechanism remains unknown. The GluA1 subunit of AMPAR is a key molecule for learning and synaptic plasticity, which requires trafficking of GluA1-containing AMPARs into the synapse. METHODS Adult male rats were exposed to 1.8% isoflurane for 2 h and subjected to an inhibitory avoidance task, which is a hippocampus-dependent contextual fear learning paradigm (n = 16 to 39). The in vitro extracellular field potential of hippocampal synapses between the Schaffer collateral and the CA1 was evaluated using a multielectrode recorder (n = 6 per group). GluA1 expression in the synaptoneurosome was assessed using Western blotting (n = 5 to 8). The ubiquitination level of GluA1 was evaluated using immunoprecipitation and Western blotting (n = 7 per group). RESULTS Seven days after exposure to 1.8% isoflurane for 2 h (Iso1.8), the inhibitory avoidance learning (control vs. Iso1.8; 294 ± 34 vs. 138 ± 28, the mean ± SEM [%]; P = 0.002) and long-term potentiation (125.7 ± 6.1 vs. 105.7 ± 3.3; P < 0.001) were impaired. Iso1.8 also temporarily increased GluA1 in the synaptoneurosomes (100 ± 9.7 vs. 138.9 ± 8.9; P = 0.012) and reduced the GluA1 ubiquitination, a main degradation pathway of GluA1 (100 ± 8.7 vs. 71.1 ± 6.1; P = 0.014). CONCLUSIONS Isoflurane impairs hippocampal learning and modulates synaptic plasticity in the postanesthetic period. Increased GluA1 may reduce synaptic capacity for additional GluA1-containing AMPARs trafficking.
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12
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A cholinergic trigger drives learning-induced plasticity at hippocampal synapses. Nat Commun 2014; 4:2760. [PMID: 24217681 PMCID: PMC3831287 DOI: 10.1038/ncomms3760] [Citation(s) in RCA: 110] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Accepted: 10/14/2013] [Indexed: 12/31/2022] Open
Abstract
Learning induces plastic changes in synapses. However, the regulatory molecules that orchestrate learning-induced synaptic changes are largely unknown. Although it is well established that cholinergic inputs from the medial septum modulate learning and memory, evidence for the cholinergic regulation of learning-induced synaptic plasticity is lacking. Here we find that the activation of muscarinic acetylcholine (ACh) receptors (mAChRs) mediates the contextual fear learning-driven strengthening of hippocampal excitatory pyramidal synapses through the synaptic incorporation of AMPA-type glutamate receptors (AMPARs). Contextual fear learning also enhances the strength of inhibitory synapses on hippocampal pyramidal CA1 neurons, in a manner mediated by the activation of, not mAChRs, but, nicotinic AChRs (nAChRs). We observe a significant correlation between the learning-induced increases in excitatory and inhibitory synaptic strength at individual pyramidal neurons. Understanding the mechanisms underlying cholinergic regulation of learning-induced hippocampal synaptic plasticity may help the development of new therapies for cognitive disorders. Cholinergic signalling modulates learning and memory; however, its influence on learning-induced synaptic plasticity is less clear. Mitsushima et al. show that acetylcholine simultaneously strengthens both excitatory and inhibitory synapses onto CA1 pyramidal neurons following an inhibitory avoidance task.
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13
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Lohmann C, Kessels HW. The developmental stages of synaptic plasticity. J Physiol 2014; 592:13-31. [PMID: 24144877 PMCID: PMC3903349 DOI: 10.1113/jphysiol.2012.235119] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Accepted: 10/16/2013] [Indexed: 01/17/2023] Open
Abstract
The brain is programmed to drive behaviour by precisely wiring the appropriate neuronal circuits. Wiring and rewiring of neuronal circuits largely depends on the orchestrated changes in the strengths of synaptic contacts. Here, we review how the rules of synaptic plasticity change during development of the brain, from birth to independence. We focus on the changes that occur at the postsynaptic side of excitatory glutamatergic synapses in the rodent hippocampus and neocortex. First we summarize the current data on the structure of synapses and the developmental expression patterns of the key molecular players of synaptic plasticity, N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, as well as pivotal kinases (Ca(2+)/calmodulin-dependent protein kinase II, protein kinase A, protein kinase C) and phosphatases (PP1, PP2A, PP2B). In the second part we relate these findings to important characteristics of the emerging network. We argue that the concerted and gradual shifts in the usage of plasticity molecules comply with the changing need for (re)wiring neuronal circuits.
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Affiliation(s)
- Christian Lohmann
- C. Lohmann and H. W. Kessels: The Netherlands Institute for Neuroscience, the Royal Academy of Arts and Sciences, Meibergdreef 47, 1105 BA, Amsterdam, the Netherlands. Emails: ,
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14
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Tada H, Kuroki Y, Funabashi T, Kamiya Y, Goto T, Suyama K, Sano A, Mitsushima D, Etgen AM, Takahashi T. Phasic synaptic incorporation of GluR2-lacking AMPA receptors at gonadotropin-releasing hormone neurons is involved in the generation of the luteinizing hormone surge in female rats. Neuroscience 2013; 248:664-9. [PMID: 23811398 DOI: 10.1016/j.neuroscience.2013.06.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Revised: 06/05/2013] [Accepted: 06/19/2013] [Indexed: 11/17/2022]
Abstract
Reproductive success depends on a robust and appropriately timed preovulatory luteinizing hormone (LH) surge, which is induced by the activation of gonadotropin-releasing hormone (GnRH) neurons in response to positive feedback from increasing estrogen levels. Here we document an increase in postsynaptic GluR2-lacking Ca2+ -permeable AMPA-type glutamate receptors (CP-AMPARs) at synapses on GnRH neurons on the day of proestrus in rats, coincident with the increase in estrogen levels. Functional blockade of CP-AMPARs depressed the synaptic responses only on the day of proestrus and concomitantly attenuated the LH surge. Thus, the phasic synaptic incorporation of postsynaptic CP-AMPARs on GnRH neurons is involved in the generation of the LH surge.
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Affiliation(s)
- H Tada
- Department of Physiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama 236-0004, Japan
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15
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Miyazaki T, Kunii M, Jitsuki S, Sano A, Kuroiwa Y, Takahashi T. Social isolation perturbs experience-driven synaptic glutamate receptor subunit 4 delivery in the developing rat barrel cortex. Eur J Neurosci 2013; 37:1602-9. [PMID: 23510259 DOI: 10.1111/ejn.12188] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 02/12/2013] [Accepted: 02/14/2013] [Indexed: 11/27/2022]
Abstract
In neonates, the stress of social isolation can alter developing neural circuits and cause mental illness. However, the molecular and cellular bases for these effects are poorly understood. Experience-driven synaptic AMPA receptor delivery is crucial for circuit organisation during development. In the rat, whisker experience drives the delivery of glutamate receptor subunit 4 (GluA4) but not glutamate receptor subunit 1 (GluA1) to layer 4-2/3 pyramidal synapses in the barrel cortex during postnatal day (P)8-10, whereas GluA1 but not GluA4 is delivered to these synapses during P12-14. We recently reported that early social isolation disrupts experience-driven GluA1 delivery to layer 4-2/3 pyramidal synapses during P12-14. Here, we report that neonatal isolation affects even earlier stages of development by preventing experience-dependent synaptic GluA4 delivery. Thus, social isolation severely affects synaptic maturation throughout early postnatal development.
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Affiliation(s)
- Tomoyuki Miyazaki
- Yokohama City University Graduate School of Medicine, Department of Physiology, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
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In vivo quantitative proteomics of somatosensory cortical synapses shows which protein levels are modulated by sensory deprivation. Proc Natl Acad Sci U S A 2013; 110:E726-35. [PMID: 23382246 DOI: 10.1073/pnas.1300424110] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Postnatal bilateral whisker trimming was used as a model system to test how synaptic proteomes are altered in barrel cortex by sensory deprivation during synaptogenesis. Using quantitative mass spectrometry, we quantified more than 7,000 synaptic proteins and identified 89 significantly reduced and 161 significantly elevated proteins in sensory-deprived synapses, 22 of which were validated by immunoblotting. More than 95% of quantified proteins, including abundant synaptic proteins such as PSD-95 and gephyrin, exhibited no significant difference under high- and low-activity rearing conditions, suggesting no tissue-wide changes in excitatory or inhibitory synaptic density. In contrast, several proteins that promote mature spine morphology and synaptic strength, such as excitatory glutamate receptors and known accessory factors, were reduced significantly in deprived synapses. Immunohistochemistry revealed that the reduction in SynGAP1, a postsynaptic scaffolding protein, was restricted largely to layer I of barrel cortex in sensory-deprived rats. In addition, protein-degradation machinery such as proteasome subunits, E2 ligases, and E3 ligases, accumulated significantly in deprived synapses, suggesting targeted synaptic protein degradation under sensory deprivation. Importantly, this screen identified synaptic proteins whose levels were affected by sensory deprivation but whose synaptic roles have not yet been characterized in mammalian neurons. These data demonstrate the feasibility of defining synaptic proteomes under different sensory rearing conditions and could be applied to elucidate further molecular mechanisms of sensory development.
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Developmental switch in spike timing-dependent plasticity at layers 4-2/3 in the rodent barrel cortex. J Neurosci 2013; 32:15000-11. [PMID: 23100422 DOI: 10.1523/jneurosci.2506-12.2012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sensory deprivation during the critical period induces long-lasting changes in cortical maps. In the rodent somatosensory cortex (S1), its precise initiation mechanism is not known, yet spike timing-dependent plasticity (STDP) at layer 4 (L4)-L2/3 synapses are thought to be crucial. Whisker stimulation causes "L4 followed by L2/3" cell firings, while acute single whisker deprivation suddenly reverses the sequential order in L4 and L2/3 neurons in the deprived column (Celikel et al., 2004). Reversed spike sequence then leads to long-term depression through an STDP mechanism (timing-dependent long-term depression), known as deprivation-induced suppression at L4-L2/3 synapses (Bender et al., 2006a), an important first step in the map reorganization. Here we show that STDP properties change dramatically on postnatal day 13-15 (P13-P15) in mice S1. Before P13, timing-dependent long-term potentiation (t-LTP) was predominantly induced regardless of spiking order. The induction of t-LTP required postsynaptic influx of Ca(2+), an activation of protein kinase A, but not calcium/calmodulin-dependent protein kinase II. Consistent with the strong bias toward t-LTP, whisker deprivation (all whiskers in Row "D") from P7-P12 failed to induce synaptic depression at L4-L2/3 synapses in the deprived column, but clear depression was seen if deprivation occurred after P14. Random activation of L4, L2/3 cells, as may occur in response to whisker stimulation before P13 during network formation, led to potentiation under the immature STDP rule, as predicted from the bias toward t-LTP regardless of spiking order. These findings describe a developmental switch in the STDP rule that may underlie the transition from synapse formation to circuit reorganization at L4-L2/3 synapses, both in distinct activity-dependent manners.
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Miyazaki T, Takase K, Nakajima W, Tada H, Ohya D, Sano A, Goto T, Hirase H, Malinow R, Takahashi T. Disrupted cortical function underlies behavior dysfunction due to social isolation. J Clin Invest 2012; 122:2690-701. [PMID: 22706303 DOI: 10.1172/jci63060] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Accepted: 05/09/2012] [Indexed: 01/21/2023] Open
Abstract
Stressful events during early childhood can have a profound lifelong influence on emotional and cognitive behaviors. However, the mechanisms by which stress affects neonatal brain circuit formation are poorly understood. Here, we show that neonatal social isolation disrupts molecular, cellular, and circuit developmental processes, leading to behavioral dysfunction. Neonatal isolation prevented long-term potentiation and experience-dependent synaptic trafficking of α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors normally occurring during circuit formation in the rodent barrel cortex. This inhibition of AMPA receptor trafficking was mediated by an increase of the stress glucocorticoid hormone and was associated with reduced calcium/calmodulin-dependent protein kinase type II (CaMKII) signaling, resulting in attenuated whisker sensitivity at the cortex. These effects led to defects in whisker-dependent behavior in juvenile animals. These results indicate that neonatal social isolation alters neuronal plasticity mechanisms and perturbs the initial establishment of a normal cortical circuit, which potentially explains the long-lasting behavioral effects of neonatal stress.
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Affiliation(s)
- Tomoyuki Miyazaki
- Department of Physiology, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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