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Ghane MA, Wei W, Yakout DW, Allen ZD, Miller CL, Dong B, Yang JJ, Fang N, Mabb AM. Arc ubiquitination regulates endoplasmic reticulum-mediated Ca 2+ release and CaMKII signaling. Front Cell Neurosci 2023; 17:1091324. [PMID: 36998269 PMCID: PMC10043188 DOI: 10.3389/fncel.2023.1091324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 02/22/2023] [Indexed: 03/17/2023] Open
Abstract
Synaptic plasticity relies on rapid, yet spatially precise signaling to alter synaptic strength. Arc is a brain enriched protein that is rapidly expressed during learning-related behaviors and is essential for regulating metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD). We previously showed that disrupting the ubiquitination capacity of Arc enhances mGluR-LTD; however, the consequences of Arc ubiquitination on other mGluR-mediated signaling events is poorly characterized. Here we find that pharmacological activation of Group I mGluRs with S-3,5-dihydroxyphenylglycine (DHPG) increases Ca2+ release from the endoplasmic reticulum (ER). Disrupting Arc ubiquitination on key amino acid residues enhances DHPG-induced ER-mediated Ca2+ release. These alterations were observed in all neuronal subregions except secondary branchpoints. Deficits in Arc ubiquitination altered Arc self-assembly and enhanced its interaction with calcium/calmodulin-dependent protein kinase IIb (CaMKIIb) and constitutively active forms of CaMKII in HEK293 cells. Colocalization of Arc and CaMKII was altered in cultured hippocampal neurons, with the notable exception of secondary branchpoints. Finally, disruptions in Arc ubiquitination were found to increase Arc interaction with the integral ER protein Calnexin. These results suggest a previously unknown role for Arc ubiquitination in the fine tuning of ER-mediated Ca2+ signaling that may support mGluR-LTD, which in turn, may regulate CaMKII and its interactions with Arc.
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Affiliation(s)
- Mohammad A. Ghane
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Wei Wei
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Dina W. Yakout
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Zachary D. Allen
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
| | - Cassandra L. Miller
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Bin Dong
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Jenny J. Yang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
- Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, United States
| | - Ning Fang
- Department of Chemistry, Georgia State University, Atlanta, GA, United States
| | - Angela M. Mabb
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
- Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, United States
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2
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Funke JR, Hwang EK, Wunsch AM, Baker R, Engeln KA, Murray CH, Milovanovic M, Caccamise AJ, Wolf ME. Persistent Neuroadaptations in the Nucleus Accumbens Core Accompany Incubation of Methamphetamine Craving in Male and Female Rats. eNeuro 2023; 10:ENEURO.0480-22.2023. [PMID: 36792361 PMCID: PMC10016192 DOI: 10.1523/eneuro.0480-22.2023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/06/2023] [Accepted: 01/10/2023] [Indexed: 02/17/2023] Open
Abstract
Relapse is a major problem in treating methamphetamine use disorder. "Incubation of craving" during abstinence is a rat model for persistence of vulnerability to craving and relapse. While methamphetamine incubation has previously been demonstrated in male and female rats, it has not been demonstrated after withdrawal periods greater than 51 d and most mechanistic work used males. Here, we address both gaps. First, although methamphetamine intake was higher in males during self-administration training (6 h/d × 10 d), incubation was similar in males and females, with "incubated" craving persisting through withdrawal day (WD)100. Second, using whole-cell patch-clamp recordings in medium spiny neurons (MSNs) of the nucleus accumbens (NAc) core, we assessed synaptic levels of calcium-permeable AMPA receptors (CP-AMPARs), as their elevation is required for expression of incubation in males. In both sexes, compared with saline-self-administering controls, CP-AMPAR levels were significantly higher in methamphetamine rats across withdrawal, although this was less pronounced in WD100-135 rats than WD15-35 or WD40-75 methamphetamine rats. We also examined membrane properties and NMDA receptor (NMDAR) transmission. In saline controls, MSNs from males exhibited lower excitability than females. This difference was eliminated after incubation because of increased excitability of MSNs from males. NMDAR transmission did not differ between sexes and was not altered after incubation. In conclusion, incubation persists for longer than previously described and equally persistent CP-AMPAR plasticity in NAc core occurs in both sexes. Thus, abstinence-related synaptic plasticity in NAc is similar in males and females although other methamphetamine-related behaviors and neuroadaptations show differences.
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Affiliation(s)
- Jonathan R Funke
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Eun-Kyung Hwang
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Amanda M Wunsch
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Raines Baker
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Kimberley A Engeln
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Conor H Murray
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Mike Milovanovic
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Aaron J Caccamise
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
| | - Marina E Wolf
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064
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3
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Developmental Inhibitory Changes in the Primary Somatosensory Cortex of the Stargazer Mouse Model of Absence Epilepsy. Biomolecules 2023; 13:biom13010186. [PMID: 36671571 PMCID: PMC9856073 DOI: 10.3390/biom13010186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 01/08/2023] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
Childhood absence epilepsy seizures arise in the cortico-thalamocortical network due to multiple cellular and molecular mechanisms, which are still under investigation. Understanding the precise mechanisms is imperative given that treatment fails in ~30% of patients while adverse neurological sequelae remain common. Impaired GABAergic neurotransmission is commonly reported in research models investigating these mechanisms. Recently, we reported a region-specific reduction in the whole-tissue and synaptic GABAA receptor (GABAAR) α1 subunit and an increase in whole-tissue GAD65 in the primary somatosensory cortex (SoCx) of the adult epileptic stargazer mouse compared with its non-epileptic (NE) littermate. The current study investigated whether these changes occurred prior to the onset of seizures on postnatal days (PN) 17-18, suggesting a causative role. Synaptic and cytosolic fractions were biochemically isolated from primary SoCx lysates followed by semiquantitative Western blot analyses for GABAAR α1 and GAD65. We found no significant changes in synaptic GABAAR α1 and cytosolic GAD65 in the primary SoCx of the stargazer mice at the critical developmental stages of PN 7-9, 13-15, and 17-18. This indicates that altered levels of GABAAR α1 and GAD65 in adult mice do not directly contribute to the initial onset of absence seizures but are a later consequence of seizure activity.
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GluN3-Containing NMDA Receptors in the Rat Nucleus Accumbens Core Contribute to Incubation of Cocaine Craving. J Neurosci 2021; 41:8262-8277. [PMID: 34413203 DOI: 10.1523/jneurosci.0406-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 11/21/2022] Open
Abstract
Cue-induced cocaine craving progressively intensifies (incubates) after withdrawal from cocaine self-administration in rats and humans. In rats, the expression of incubation ultimately depends on Ca2+-permeable AMPARs that accumulate in synapses onto medium spiny neurons (MSNs) in the NAc core. However, the delay in their accumulation (∼1 month after drug self-administration ceases) suggests earlier waves of plasticity. This prompted us to conduct the first study of NMDAR transmission in NAc core during incubation, focusing on the GluN3 subunit, which confers atypical properties when incorporated into NMDARs, including insensitivity to Mg2+ block and Ca2+ impermeability. Whole-cell patch-clamp recordings were conducted in MSNs of adult male rats 1-68 d after discontinuing extended-access saline or cocaine self-administration. NMDAR transmission was enhanced after 5 d of cocaine withdrawal, and this persisted for at least 68 d of withdrawal. The earliest functional alterations were mediated through increased contributions of GluN2B-containing NMDARs, followed by increased contributions of GluN3-containing NMDARs. As predicted by GluN3-NMDAR incorporation, fewer MSN spines exhibited NMDAR-mediated Ca2+ entry. GluN3A knockdown in NAc core was sufficient to prevent incubation of craving, consistent with biotinylation studies showing increased GluN3A surface expression, although array tomography studies suggested that adaptations involving GluN3B also occur. Collectively, our data show that a complex cascade of NMDAR and AMPAR plasticity occurs in NAc core, potentially through a homeostatic mechanism, leading to persistent increases in cocaine cue reactivity and relapse vulnerability. This is a remarkable example of experience-dependent glutamatergic plasticity evolving over a protracted window in the adult brain.SIGNIFICANCE STATEMENT "Incubation of craving" is an animal model for the persistence of vulnerability to cue-induced relapse after prolonged drug abstinence. Incubation also occurs in human drug users. AMPAR plasticity in medium spiny neurons (MSNs) of the NAc core is critical for incubation of cocaine craving but occurs only after a delay. Here we found that AMPAR plasticity is preceded by NMDAR plasticity that is essential for incubation and involves GluN3, an atypical NMDAR subunit that markedly alters NMDAR transmission. Together with AMPAR plasticity, this represents profound remodeling of excitatory synaptic transmission onto MSNs. Given the importance of MSNs for translating motivation into action, this plasticity may explain, at least in part, the profound shifts in motivated behavior that characterize addiction.
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5
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Mao LM, Wang JQ. Alterations in mGlu5 receptor expression and function in the striatum in a rat depression model. J Neurochem 2018; 145:287-298. [PMID: 29337350 DOI: 10.1111/jnc.14307] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 12/27/2017] [Accepted: 01/03/2018] [Indexed: 12/24/2022]
Abstract
Major depressive disorder is a common form of mental illness. Many brain regions are implicated in the pathophysiology and symptomatology of depression. Among key brain areas is the striatum that controls reward and mood and is involved in the development of core depression-like behavior in animal models of depression. While molecular mechanisms in this region underlying depression-related behavior are poorly understood, the glutamatergic input to the striatum is believed to play a role. In this study, we investigated changes in metabotropic glutamate (mGlu) receptor expression and signaling in the striatum of adult rats in response to prolonged (10-12 weeks) social isolation, a pre-validated animal paradigm modeling depression in adulthood. We found that mGlu5 receptor protein levels in the striatum were increased in rats that showed typical depression- and anxiety-like behavior after chronic social isolation. This increase in mGlu5 receptor expression was seen in both subdivisions of the striatum, the nucleus accumbens and caudate putamen. At subcellular and subsynaptic levels, mGlu5 receptor expression was elevated in surface membranes at synaptic sites. In striatal neurons, the mGlu5-associated phosphoinositide signaling pathway was augmented in its efficacy after prolonged social isolation. These data indicate that the mGlu5 receptor is a sensitive substrate of depression. Adulthood social isolation leads to the up-regulation of mGlu5 receptor expression and function in striatal neurons.
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Affiliation(s)
- Li-Min Mao
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
| | - John Q Wang
- Department of Biomedical Sciences, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA.,Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, Missouri, USA
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6
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Adotevi NK, Leitch B. Synaptic Changes in AMPA Receptor Subunit Expression in Cortical Parvalbumin Interneurons in the Stargazer Model of Absence Epilepsy. Front Mol Neurosci 2017; 10:434. [PMID: 29311821 PMCID: PMC5744073 DOI: 10.3389/fnmol.2017.00434] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 12/15/2017] [Indexed: 11/15/2022] Open
Abstract
Feedforward inhibition is essential to prevent run away excitation within the brain. Recent evidence suggests that a loss of feed-forward inhibition in the corticothalamocortical circuitry may underlie some absence seizures. However, it is unclear if this aberration is specifically linked to loss of synaptic excitation onto local fast-spiking parvalbumin-containing (PV+) inhibitory interneurons, which are responsible for mediating feedforward inhibition within cortical networks. We recently reported a global tissue loss of AMPA receptors (AMPARs), and a specific mistrafficking of these AMPARs in PV+ interneurons in the stargazer somatosensory cortex. The current study was aimed at investigating if cellular changes in AMPAR expression were translated into deficits in receptors at specific synapses in the feedforward inhibitory microcircuit. Using western blot immunolabeling on biochemically isolated synaptic fractions, we demonstrate a loss of AMPAR GluA1–4 subunits in the somatosensory cortex of stargazers compared to non-epileptic control mice. Furthermore, using double post-embedding immunogold-cytochemistry, we show a loss of GluA1–4-AMPARs at excitatory synapses onto cortical PV+ interneurons. Altogether, these data indicate a loss of synaptic AMPAR-mediated excitation of cortical PV+ inhibitory neurons. As the cortex is considered the site of initiation of spike wave discharges (SWDs) within the corticothalamocortical circuitry, loss of AMPARs at cortical PV+ interneurons likely impairs feed-forward inhibitory output, and contributes to the generation of SWDs and absence seizures in stargazers.
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Affiliation(s)
- Nadia K Adotevi
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Beulah Leitch
- Department of Anatomy, Brain Health Research Centre, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
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7
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Barad Z, Grattan DR, Leitch B. NMDA Receptor Expression in the Thalamus of the Stargazer Model of Absence Epilepsy. Sci Rep 2017; 7:42926. [PMID: 28220891 PMCID: PMC5318904 DOI: 10.1038/srep42926] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 01/16/2017] [Indexed: 11/09/2022] Open
Abstract
In the stargazer mouse model of absence epilepsy, altered corticothalamic excitation of reticular thalamic nucleus (RTN) neurons has been suggested to contribute to abnormal synchronicity in the corticothalamic-thalamocortical circuit, leading to spike-wave discharges, the hallmark of absence seizures. AMPA receptor expression and function are decreased in stargazer RTN, due to a mutation of AMPAR auxiliary subunit stargazin. It is unresolved and debated, however, if decreased excitation of RTN is compatible with epileptogenesis. We tested the hypothesis that relative NMDAR expression may be increased in RTN and/or thalamic synapses in stargazers using Western blot on dissected thalamic nuclei and biochemically isolated synapses, as well as immunogold cytochemistry in RTN. Expression of main NMDAR subunits was variable in stargazer RTN and relay thalamus; however, mean expression values were not statistically significantly different compared to controls. Furthermore, no systematic changes in synaptic NMDAR levels could be detected in stargazer thalamus. In contrast, AMPAR subunits were markedly decreased in both nucleus-specific and synaptic preparations. Thus, defective AMPAR trafficking in stargazer thalamus does not appear to lead to a ubiquitous compensatory increase in total and synaptic NMDAR expression, suggesting that elevated NMDAR function is not mediated by changes in protein expression in stargazer mice.
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Affiliation(s)
- Z Barad
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - D R Grattan
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Centre for Neuroendocrinology, Dunedin, New Zealand
| | - B Leitch
- Department of Anatomy, Otago School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.,Brain Health Research Centre, University of Otago, Dunedin, New Zealand
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8
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O'Leary H, Bernard PB, Castano AM, Benke TA. Enhanced long term potentiation and decreased AMPA receptor desensitization in the acute period following a single kainate induced early life seizure. Neurobiol Dis 2015; 87:134-44. [PMID: 26706598 DOI: 10.1016/j.nbd.2015.12.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 11/17/2015] [Accepted: 12/14/2015] [Indexed: 02/04/2023] Open
Abstract
Neonatal seizures are associated with long term disabilities including epilepsy and cognitive deficits. Using a neonatal seizure rat model that does not develop epilepsy, but develops a phenotype consistent with other models of intellectual disability (ID) and autism spectrum disorders (ASD), we sought to isolate the acute effects of a single episode of early life seizure on hippocampal CA1 synaptic development and plasticity. We have previously shown chronic changes in glutamatergic synapses, loss of long term potentiation (LTP) and enhanced long term depression (LTD), in the adult male rat ~50days following kainic acid (KA) induced early life seizure (KA-ELS) in post-natal (P) 7day old male Sprague-Dawley rats. In the present work, we examined the electrophysiological properties and expression levels of glutamate receptors in the acute period, 2 and 7days, post KA-ELS. Our results show for the first time enhanced LTP 7days after KA-ELS, but no change 2days post KA-ELS. Additionally, we report that ionotropic α-amino-3-hydroxy-5-methyl-isoxazole-propionic acid type glutamate receptor (AMPAR) desensitization is decreased in the same time frame, with no changes in AMPAR expression, phosphorylation, or membrane insertion. Inappropriate enhancement of the synaptic connections in the acute period after the seizure could alter the normal patterning of synaptic development in the hippocampus during this critical period and contribute to learning deficits. Thus, this study demonstrates a novel mechanism by which KA-ELS alters early network properties that potentially lead to adverse outcomes.
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Affiliation(s)
- Heather O'Leary
- Department of Pediatrics, University of Colorado, School of Medicine, 80045, USA
| | - Paul B Bernard
- Department of Pediatrics, University of Colorado, School of Medicine, 80045, USA
| | - Anna M Castano
- Department of Pediatrics, University of Colorado, School of Medicine, 80045, USA
| | - Tim A Benke
- Department of Pediatrics, University of Colorado, School of Medicine, 80045, USA; Department of Neurology, University of Colorado, School of Medicine, 80045, USA; Department of Pharmacology, University of Colorado, School of Medicine, 80045, USA; Department of Otolaryngology, University of Colorado, School of Medicine, 80045, USA; Neuroscience Graduate Program, University of Colorado, School of Medicine, 80045, USA.
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9
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Otmakhov N, Gorbacheva EV, Regmi S, Yasuda R, Hudmon A, Lisman J. Excitotoxic insult results in a long-lasting activation of CaMKIIα and mitochondrial damage in living hippocampal neurons. PLoS One 2015; 10:e0120881. [PMID: 25793533 PMCID: PMC4368532 DOI: 10.1371/journal.pone.0120881] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Accepted: 02/11/2015] [Indexed: 12/11/2022] Open
Abstract
Over-activation of excitatory NMDA receptors and the resulting Ca2+ overload is the main cause of neuronal toxicity during stroke. CaMKII becomes misregulated during such events. Biochemical studies show either a dramatic loss of CaMKII activity or its persistent autonomous activation after stroke, with both of these processes being implicated in cell toxicity. To complement the biochemical data, we monitored CaMKII activation in living hippocampal neurons in slice cultures using high spatial/temporal resolution two-photon imaging of the CaMKIIα FRET sensor, Camui. CaMKII activation state was estimated by measuring Camui fluorescence lifetime. Short NMDA insult resulted in Camui activation followed by a redistribution of its protein localization: an increase in spines, a decrease in dendritic shafts, and concentration into numerous clusters in the cell soma. Camui activation was either persistent (> 1-3 hours) or transient (~20 min) and, in general, correlated with its protein redistribution. After longer NMDA insult, however, Camui redistribution persisted longer than its activation, suggesting distinct regulation/phases of these processes. Mutational and pharmacological analysis suggested that persistent Camui activation was due to prolonged Ca2+ elevation, with little impact of autonomous states produced by T286 autophosphorylation and/or by C280/M281 oxidation. Cell injury was monitored using expressible mitochondrial marker mito-dsRed. Shortly after Camui activation and clustering, NMDA treatment resulted in mitochondrial swelling, with persistence of the swelling temporarily linked to the persistence of Camui activation. The results suggest that in living neurons excitotoxic insult produces long-lasting Ca2+-dependent active state of CaMKII temporarily linked to cell injury. CaMKII function, however, is to be restricted due to strong clustering. The study provides the first characterization of CaMKII activation dynamics in living neurons during excitotoxic insults.
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Affiliation(s)
- Nikolai Otmakhov
- Biology Department, Brandeis University, Waltham, Massachusetts, 02454, United States of America
- * E-mail:
| | - Elena V. Gorbacheva
- Biology Department, Brandeis University, Waltham, Massachusetts, 02454, United States of America
| | - Shaurav Regmi
- Biology Department, Brandeis University, Waltham, Massachusetts, 02454, United States of America
| | - Ryohei Yasuda
- Max Planck Florida Institute, One Max Planck Way, Jupiter, Florida, 33458, United States of America
| | - Andy Hudmon
- STARK Neuroscience Research Institute, Indiana University School of Medicine, 950 West Walnut Street, Research Building II, Room 480, Indianapolis, Indiana, 46202, United States of America
| | - John Lisman
- Biology Department, Brandeis University, Waltham, Massachusetts, 02454, United States of America
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10
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Corsetti V, Florenzano F, Atlante A, Bobba A, Ciotti MT, Natale F, Della Valle F, Borreca A, Manca A, Meli G, Ferraina C, Feligioni M, D'Aguanno S, Bussani R, Ammassari-Teule M, Nicolin V, Calissano P, Amadoro G. NH2-truncated human tau induces deregulated mitophagy in neurons by aberrant recruitment of Parkin and UCHL-1: implications in Alzheimer's disease. Hum Mol Genet 2015; 24:3058-81. [PMID: 25687137 DOI: 10.1093/hmg/ddv059] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/10/2015] [Indexed: 01/26/2023] Open
Abstract
Disarrangement in functions and quality control of mitochondria at synapses are early events in Alzheimer's disease (AD) pathobiology. We reported that a 20-22 kDa NH2-tau fragment mapping between 26 and 230 amino acids of the longest human tau isoform (aka NH2htau): (i) is detectable in cellular and animal AD models, as well in synaptic mitochondria and cerebrospinal fluids (CSF) from human AD subjects; (ii) is neurotoxic in primary hippocampal neurons; (iii) compromises the mitochondrial biology both directly, by inhibiting the ANT-1-dependent ADP/ATP exchange, and indirectly, by impairing their selective autophagic clearance (mitophagy). Here, we show that the extensive Parkin-dependent turnover of mitochondria occurring in NH2htau-expressing post-mitotic neurons plays a pro-death role and that UCHL-1, the cytosolic Ubiquitin-C-terminal hydrolase L1 which directs the physiological remodeling of synapses by controlling ubiquitin homeostasis, critically contributes to mitochondrial and synaptic failure in this in vitro AD model. Pharmacological or genetic suppression of improper mitophagy, either by inhibition of mitochondrial targeting to autophagosomes or by shRNA-mediated silencing of Parkin or UCHL-1 gene expression, restores synaptic and mitochondrial content providing partial but significant protection against the NH2htau-induced neuronal death. Moreover, in mitochondria from human AD synapses, the endogenous NH2htau is stably associated with Parkin and with UCHL-1. Taken together, our studies show a causative link between the excessive mitochondrial turnover and the NH2htau-induced in vitro neuronal death, suggesting that pathogenetic tau truncation may contribute to synaptic deterioration in AD by aberrant recruitment of Parkin and UCHL-1 to mitochondria making them more prone to detrimental autophagic clearance.
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Affiliation(s)
- V Corsetti
- Institute of Translational Pharmacology (IFT) - National Research Council (CNR), Via Fosso del Cavaliere 100-00133, Rome, Italy
| | - F Florenzano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Atlante
- Institute of Biomembranes and Bioenergetics (IBBE)-CNR, Via Amendola 165/A, 70126 Bari, Italy
| | - A Bobba
- Institute of Biomembranes and Bioenergetics (IBBE)-CNR, Via Amendola 165/A, 70126 Bari, Italy
| | - M T Ciotti
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - F Natale
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - F Della Valle
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Borreca
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - A Manca
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - G Meli
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - C Ferraina
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - M Feligioni
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - S D'Aguanno
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - R Bussani
- UCO Pathological Anatomy and Histopathology Unit, Cattinara Hospital Strada di Fiume 447, 34149 Trieste, Italy and
| | - M Ammassari-Teule
- Institute of Cellular Biology and Neuroscience (IBCN)-CNR, IRCSS Santa Lucia Foundation Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - V Nicolin
- Department of Medical, Surgical and Health Science, University of Trieste, Strada di Fiume 449, 34149 Trieste, Italy
| | - P Calissano
- European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
| | - G Amadoro
- Institute of Translational Pharmacology (IFT) - National Research Council (CNR), Via Fosso del Cavaliere 100-00133, Rome, Italy European Brain Research Institute (EBRI), Via del Fosso di Fiorano 64-65, 00143 Rome, Italy
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11
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Orfila JE, Shimizu K, Garske AK, Deng G, Maylie J, Traystman RJ, Quillinan N, Adelman JP, Herson PS. Increasing small conductance Ca2+-activated potassium channel activity reverses ischemia-induced impairment of long-term potentiation. Eur J Neurosci 2014; 40:3179-88. [PMID: 25080203 DOI: 10.1111/ejn.12683] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 06/30/2014] [Accepted: 07/08/2014] [Indexed: 11/28/2022]
Abstract
Global cerebral ischemia following cardiac arrest and cardiopulmonary resuscitation (CA/CPR) causes injury to hippocampal CA1 pyramidal neurons and impairs cognition. Small conductance Ca(2+)-activated potassium channels type 2 (SK2), expressed in CA1 pyramidal neurons, have been implicated as potential protective targets. Here we showed that, in mice, hippocampal long-term potentiation (LTP) was impaired as early as 3 h after recovery from CA/CPR and LTP remained impaired for at least 30 days. Treatment with the SK2 channel agonist 1-Ethyl-2-benzimidazolinone (1-EBIO) at 30 min after CA provided sustained protection from plasticity deficits, with LTP being maintained at control levels at 30 days after recovery from CA/CPR. Minimal changes in glutamate release probability were observed at delayed times after CA/CPR, implicating post-synaptic mechanisms. Real-time quantitative reverse transcriptase-polymerase chain reaction indicated that CA/CPR did not cause a loss of N-methyl-D-aspartate (NMDA) receptor mRNA at 7 or 30 days after CA/CPR. Similarly, no change in synaptic NMDA receptor protein levels was observed at 7 or 30 days after CA/CPR. Further, patch-clamp experiments demonstrated no change in functional synaptic NMDA receptors at 7 or 30 days after CA/CPR. Electrophysiology recordings showed that synaptic SK channel activity was reduced for the duration of experiments performed (up to 30 days) and that, surprisingly, treatment with 1-EBIO did not prevent the CA/CPR-induced loss of synaptic SK channel function. We concluded that CA/CPR caused alterations in post-synaptic signaling that were prevented by treatment with the SK2 agonist 1-EBIO, indicating that activators of SK2 channels may be useful therapeutic agents to prevent ischemic injury and cognitive impairments.
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Affiliation(s)
- J E Orfila
- Department of Anesthesiology, University of Colorado School of Medicine, Aurora, CO, USA
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Xue B, Edwards MC, Mao LM, Guo ML, Jin DZ, Fibuch EE, Wang JQ. Rapid and sustained GluA1 S845 phosphorylation in synaptic and extrasynaptic locations in the rat forebrain following amphetamine administration. Neurochem Int 2013; 64:48-54. [PMID: 24231469 DOI: 10.1016/j.neuint.2013.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 10/25/2013] [Accepted: 11/03/2013] [Indexed: 12/27/2022]
Abstract
The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor is a major ionotropic glutamate receptor subtype in the mammalian brain. Like other glutamate receptors, the AMPA receptor is regulated by phosphorylation. By phosphorylating specific serine resides in AMPA receptor subunits (GluA1 and GluA2), various protein kinases regulate subcellular/subsynaptic expression and function of the receptor. In this study, we conducted a time course study to evaluate the temporal property of responses of phosphorylation at those sites to dopamine stimulation with the psychostimulant amphetamine in the adult rat striatum and medial prefrontal cortex (mPFC) in vivo. We focused on biochemically-enriched AMPA receptors from synaptic and extrasynaptic compartments. We found that acute injection of amphetamine induced a rapid and relatively sustained increase in GluA1 S845 phosphorylation at both synaptic and extrasynaptic sites in the striatum. Similar results were observed in the mPFC. In contrast to S845, amphetamine did not induce a significant change in GluA1 S831 phosphorylation in synaptic and extrasynaptic pools in the striatum and mPFC. GluA2 S880 phosphorylation in synaptic and extrasynaptic fractions in the two brain regions also remained stable in response to amphetamine. These results support S845 to be a principal site on AMPA receptors sensitive to acute stimulant exposure. Its phosphorylation levels are rapidly upregulated by amphetamine in the two defined subsynaptic microdomains (synaptic versus extrasynaptic locations) in striatal and cortical neurons.
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Affiliation(s)
- Bing Xue
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Matthew C Edwards
- Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Li-Min Mao
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Ming-Lei Guo
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Dao-Zhong Jin
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - Eugene E Fibuch
- Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
| | - John Q Wang
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA; Department of Anesthesiology, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA.
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13
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Lu Q, Harris VA, Sun X, Hou Y, Black SM. Ca²⁺/calmodulin-dependent protein kinase II contributes to hypoxic ischemic cell death in neonatal hippocampal slice cultures. PLoS One 2013; 8:e70750. [PMID: 23976956 PMCID: PMC3747161 DOI: 10.1371/journal.pone.0070750] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 06/27/2013] [Indexed: 01/23/2023] Open
Abstract
We have recently shown that p38MAP kinase (p38MAPK) stimulates ROS generation via the activation of NADPH oxidase during neonatal hypoxia-ischemia (HI) brain injury. However, how p38MAPK is activated during HI remains unresolved and was the focus of this study. Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) plays a key role in brain synapse development, neural transduction and synaptic plasticity. Here we show that CaMKII activity is stimulated in rat hippocampal slice culture exposed to oxygen glucose deprivation (OGD) to mimic the condition of HI. Further, the elevation of CaMKII activity, correlated with enhanced p38MAPK activity, increased superoxide generation from NADPH oxidase as well as necrotic and apoptotic cell death. All of these events were prevented when CaMKII activity was inhibited with KN93. In a neonatal rat model of HI, KN93 also reduced brain injury. Our results suggest that CaMKII activation contributes to the oxidative stress associated with neural cell death after HI.
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Affiliation(s)
- Qing Lu
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Valerie A. Harris
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Xutong Sun
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Yali Hou
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
| | - Stephen M. Black
- Vascular Biology Center, Georgia Regents University, Augusta, Georgia, United States of America
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14
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Mao LM, Diaz JA, Fibuch EE, Wang JQ. Regulation of phosphorylation of synaptic and extrasynaptic GluA1 AMPA receptors in the rat forebrain by amphetamine. Eur J Pharmacol 2013; 715:164-71. [PMID: 23747591 DOI: 10.1016/j.ejphar.2013.05.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Revised: 05/06/2013] [Accepted: 05/20/2013] [Indexed: 10/26/2022]
Abstract
The AMPA receptor is regulated by phosphorylation. Two major phosphorylation sites (S831 and S845) are located in the intracellular C-terminal tail of GluA1 subunits. The phosphorylation on these sites controls receptor expression and function and is subject to the regulation by psychostimulants. In this study, we further characterized the regulation of S831 and S845 phosphorylation by amphetamine (AMPH) in the adult rat striatum and medial prefrontal cortex (mPFC) in vivo. We focused on the specific fraction of GluA1/AMPA receptors enriched from synaptic and extrasynaptic membranes, using a pre-validated biochemical fractionation procedure. We found that acute AMPH administration elevated GluA1 S845 phosphorylation in the defined synaptic membrane from the striatum in a dose-dependent manner. AMPH also induced a comparable increase in S845 phosphorylation in the extrasynaptic fraction of striatal GluA1. Similar increases in S845 phosphorylation in both synaptic and extrasynaptic pools were observed in the mPFC. In contrast, S831 phosphorylation was not altered in synaptic and extrasynaptic GluA1 in striatal neurons and synaptic GluA1 in mPFC neurons in response to AMPH, although a moderate increase in S831 phosphorylation was seen in extrasynaptic GluA1 in the mPFC after an AMPH injection at a high dose. Total synaptic and extrasynaptic GluA1 expression remained stable in the two regions after AMPH administration. Our data demonstrate the differential sensitivity of S845 and S831 phosphorylation to dopamine stimulation. S845 is a primary site where phosphorylation of GluA1 is upregulated by AMPH in striatal and mPFC neurons at both synaptic and extrasynaptic compartments.
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Affiliation(s)
- Li-Min Mao
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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15
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Mao LM, Reusch JM, Fibuch EE, Liu Z, Wang JQ. Amphetamine increases phosphorylation of MAPK/ERK at synaptic sites in the rat striatum and medial prefrontal cortex. Brain Res 2012. [PMID: 23201445 DOI: 10.1016/j.brainres.2012.11.038] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mitogen-activated protein kinases (MAPKs) play a central role in cell signaling. Extracellular signal-regulated kinase (ERK) is a prototypic subclass of MAPKs and is densely expressed in postmitotic neurons of adult mammalian brains. Active ERK translocates into the nucleus to regulate gene expression. Additionally, ERK is visualized in neuronal peripheries, such as distal synaptic structures. While nuclear ERK is a known sensitive target of psychostimulants, little is known about the responsiveness of synaptic ERK to stimulants. In this study, we focused on ERK at synaptic versus extrasynaptic sites and investigated its responses to the psychostimulant amphetamine in the adult rat striatum and medial prefrontal cortex (mPFC) in vivo. We used a pre-validated biochemical fractionation procedure to isolate synapse- and extrasynapse-enriched membranes. We found that two common ERK isoforms (ERK1 and ERK2) were concentrated more in extrasynaptic fractions than in synaptic fractions in striatal and cortical neurons under normal conditions. At synaptic sites, ERK2 was noticeably more abundant than ERK1. Acute injection of amphetamine induced an increase in ERK2 phosphorylation in the synaptic fraction of striatal neurons, while the drug did not alter extrasynaptic ERK2 phosphorylation. Similar results were observed in the mPFC. In both synaptic and extrasynaptic compartments, total ERK1/2 proteins remained stable in response to amphetamine. Our data establish the subsynaptic distribution pattern of MAPK/ERK in striatal and cortical neurons. Moreover, the synaptic pool of ERK2 in these neurons can be selectively activated by amphetamine.
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Affiliation(s)
- Li-Min Mao
- Department of Basic Medical Science, School of Medicine, University of Missouri-Kansas City, Kansas City, MO 64108, USA
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Christian DT, Alexander NJ, Diaz MR, Robinson S, McCool BA. Chronic intermittent ethanol and withdrawal differentially modulate basolateral amygdala AMPA-type glutamate receptor function and trafficking. Neuropharmacology 2012; 62:2430-9. [PMID: 22387532 DOI: 10.1016/j.neuropharm.2012.02.017] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 02/15/2012] [Accepted: 02/16/2012] [Indexed: 12/19/2022]
Abstract
The amygdala plays a critical role in the generation and expression of anxiety-like behaviors including those expressed following withdrawal (WD) from chronic intermittent ethanol (CIE) exposure. In particular, the BLA glutamatergic system controls the expression of both innate and pathological anxiety. Recent data suggests that CIE and WD may functionally alter this system in a manner that closely parallels memory-related phenomena like long-term potentiation (LTP). We therefore specifically dissected CIE/WD-induced changes in glutamatergic signaling using electrophysiological and biochemical approaches with a particular focus on the plasticity-related components of this neurotransmitter system. Our results indicate that cortical glutamatergic inputs arriving at BLA principal via the external capsule undergo predominantly post-synaptic alterations in AMPA receptor function following CIE and WD. Biochemical analysis revealed treatment-dependent changes in AMPA receptor surface expression and subunit phosphorylation that are complemented by changes in total protein levels and/or phosphorylation status of several key, plasticity-associated protein kinases such as calcium/calmodulin-dependent protein kinase II (CaMKII) and protein kinase C (PKC). Together, these data show that CIE- and WD-induced changes in BLA glutamatergic function both functionally and biochemically mimic plasticity-related states. These mechanisms likely contribute to long-term increases in anxiety-like behavior following chronic ethanol exposure.
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Affiliation(s)
- Daniel T Christian
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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17
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Banerjee B, Medda BK, Schmidt J, Lang IM, Sengupta JN, Shaker R. Neuronal plasticity in the cingulate cortex of rats following esophageal acid exposure in early life. Gastroenterology 2011; 141:544-52. [PMID: 21616075 PMCID: PMC3152593 DOI: 10.1053/j.gastro.2011.04.044] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 04/04/2011] [Accepted: 04/15/2011] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS The cingulate cortex has been reported to be involved in processing pain of esophageal origin. However, little is known about molecular changes and cortical activation that arise from early-life esophageal acid reflux. Excitatory neurotransmission via activation of the N-methyl-d-aspartate (NMDA) receptor and its interaction with postsynaptic density protein 95 (PSD-95) at the synapse appear to mediate neuronal development and plasticity. We investigated the effect of early-life esophageal acid exposure on NMDA receptor subunits and PSD-95 expression in the developing cingulate cortex. METHODS We assessed NMDA receptor subunits and PSD-95 protein expression in rostral cingulate cortex (rCC) tissues of rats exposed to esophageal acid or saline (control), either during postnatal day (P) 7 to 14 and/or acutely at adult stage (P60) using immunoblot and immunoprecipitation analyses. RESULTS Compared with controls, acid exposure from P7 to P14 significantly increased expression of NR1, NR2A, and PSD-95, measured 6 weeks after exposure. However, acute exposure at P60 caused a transient increase in expression of NMDA receptor subunits. These molecular changes were more robust in animals exposed to acid neonatally and rechallenged, acutely, at P60. Esophageal acid exposure induced calcium calmodulin kinase II-mediated phosphorylation of the subunit NR2B at Ser1303. CONCLUSIONS Esophageal acid exposure during early stages of life has long-term effects as a result of phosphorylation of the NMDA receptor and overexpression in the rCC. This molecular alteration in the rCC might mediate sensitization of patients with acid-induced esophageal disorders.
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Katano T, Nakazawa T, Nakatsuka T, Watanabe M, Yamamoto T, Ito S. Involvement of spinal phosphorylation cascade of Tyr1472-NR2B, Thr286-CaMKII, and Ser831-GluR1 in neuropathic pain. Neuropharmacology 2011; 60:609-16. [DOI: 10.1016/j.neuropharm.2010.12.005] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 11/12/2010] [Accepted: 12/08/2010] [Indexed: 11/16/2022]
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19
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Ferrario CR, Loweth JA, Milovanovic M, Ford KA, Galiñanes GL, Heng LJ, Tseng KY, Wolf ME. Alterations in AMPA receptor subunits and TARPs in the rat nucleus accumbens related to the formation of Ca²⁺-permeable AMPA receptors during the incubation of cocaine craving. Neuropharmacology 2011; 61:1141-51. [PMID: 21276808 DOI: 10.1016/j.neuropharm.2011.01.021] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/20/2010] [Accepted: 01/11/2011] [Indexed: 11/30/2022]
Abstract
Cue-induced cocaine seeking intensifies or incubates after withdrawal from extended access cocaine self-administration, a phenomenon termed incubation of cocaine craving. The expression of incubated craving is mediated by Ca²⁺-permeable AMPA receptors (CP-AMPARs) in the nucleus accumbens (NAc). Thus, CP-AMPARs are a potential target for therapeutic intervention, making it important to understand mechanisms that govern their accumulation. Here we used subcellular fractionation and biotinylation of NAc tissue to examine the abundance and distribution of AMPAR subunits, and GluA1 phosphorylation, in the incubation model. We also studied two transmembrane AMPA receptor regulatory proteins (TARPs), γ-2 and γ-4. Our results, together with earlier findings, suggest that some of the new CP-AMPARs are synaptic. These are probably associated with γ-2, but they are loosely tethered to the PSD. Levels of GluA1 phosphorylated at serine 845 (pS845 GluA1) were significantly increased in biotinylated tissue and in an extrasynaptic membrane-enriched fraction. These results suggest that increased synaptic levels of CP-AMPARs may result in part from an increase in pS845 GluA1 in extrasynaptic membranes, given that S845 phosphorylation primes GluA1-containing AMPARs for synaptic insertion and extrasynaptic AMPARs supply the synapse. Some of the new extrasynaptic CP-AMPARs are likely associated with γ-4, rather than γ-2. The maintenance of CP-AMPARs in NAc synapses during withdrawal is accompanied by activation of CaMKII and ERK2 but not CaMKI. Overall, AMPAR plasticity in the incubation model shares some features with better described forms of synaptic plasticity, although the timing of the phenomenon and the persistence of related neuroadaptations are significantly different.
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Affiliation(s)
- Carrie R Ferrario
- Department of Neuroscience, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064-3095, USA.
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20
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Distribution of AMPA receptor subunits and TARPs in synaptic and extrasynaptic membranes of the adult rat nucleus accumbens. Neurosci Lett 2010; 490:180-4. [PMID: 21182898 DOI: 10.1016/j.neulet.2010.12.036] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Revised: 12/07/2010] [Accepted: 12/13/2010] [Indexed: 01/31/2023]
Abstract
We characterized the distribution of AMPA receptor (AMPAR) subunits and the transmembrane AMPA receptor regulatory proteins (TARPs) γ-2 and γ-4 in adult rat nucleus accumbens (NAc) using a method that separates plasma membranes into synaptic membrane-enriched and extrasynaptic membrane-enriched fractions. We also measured GluA1 phosphorylated at serine 845 (pS845 GluA1) and serine 831 (pS831 GluA1). GluA1-3 protein levels and pS831 GluA1/total GluA1 were higher in synaptic membranes. However, pS845 GluA1/total GluA1 was higher in extrasynaptic membranes, consistent with a role for S845 phosphorylation in GluA1 insertion at extrasynaptic sites. Homeric GluA1 receptors were detected in extrasynaptic membranes, consistent with evidence for extrasynaptic Ca(2+)-permeable AMPARs in other systems. The TARP γ-2 was enriched in synaptic membranes, whereas γ-4 was mainly found in extrasynaptic membranes, suggesting distinct roles for these proteins in the NAc. These experiments provide fundamental information that will aid in the interpretation of studies on AMPAR-related plasticity in the NAc.
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Mer receptor tyrosine kinase is a novel therapeutic target in pediatric B-cell acute lymphoblastic leukemia. Blood 2009; 114:2678-87. [PMID: 19643988 DOI: 10.1182/blood-2009-03-209247] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Acute lymphoblastic leukemia (ALL) is currently treated with an intense regimen of chemotherapy yielding cure rates near 80%. However, additional changes using available drugs are unlikely to provide significant improvement in survival. New therapies are warranted given the risk of severe therapy-associated toxicities including infertility, organ damage, and secondary malignancy. Here, we report ectopic expression of the receptor tyrosine kinase Mer in pediatric B-cell ALL. Inhibition of Mer prevented Erk 1/2 activation, increased the sensitivity of B-ALL cells to cytotoxic agents in vitro by promoting apoptosis, and delayed disease onset in a mouse model of leukemia. In addition, we discovered cross-talk between the Mer and mammalian target of rapamycin (mTOR) signaling pathways. Our results identify Mer as a novel therapeutic target in ALL and suggest that inhibitors of Mer will interact synergistically with currently used therapies. This strategy may allow for dose reduction resulting in decreased toxicity and increased survival rates. Mer is aberrantly expressed in numerous other malignancies suggesting that this approach may have broad applications.
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22
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Xu J, Kurup P, Zhang Y, Goebel-Goody SM, Wu PH, Hawasli AH, Baum ML, Bibb JA, Lombroso PJ. Extrasynaptic NMDA receptors couple preferentially to excitotoxicity via calpain-mediated cleavage of STEP. J Neurosci 2009; 29:9330-43. [PMID: 19625523 PMCID: PMC2737362 DOI: 10.1523/jneurosci.2212-09.2009] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/08/2009] [Accepted: 06/15/2009] [Indexed: 12/31/2022] Open
Abstract
NMDA receptor (NMDAR)-mediated excitotoxicity plays an important role in several CNS disorders, including epilepsy, stroke, and ischemia. Here we demonstrate the involvement of striatal-enriched protein tyrosine phosphatase (STEP) in this critical process. STEP(61) is an alternatively spliced member of the family that is present in postsynaptic terminals. In an apparent paradox, STEP(61) regulates extracellular signal-regulated kinase 1/2 (ERK1/2) and p38, two proteins with opposing functions; activated p38 promotes cell death, whereas activated ERK1/2 promotes cell survival. We found that synaptic stimulation of NMDARs promoted STEP(61) ubiquitination and degradation, concomitant with ERK1/2 activation. In contrast, extrasynaptic stimulation of NMDARs invoked calpain-mediated proteolysis of STEP(61), producing the truncated cleavage product STEP(33) and activation of p38. The calpain cleavage site on STEP was mapped to the kinase interacting motif, a domain required for substrate binding. As a result, STEP(33) neither interacts with nor dephosphorylates STEP substrates. A synthetic peptide spanning the calpain cleavage site efficiently reduced STEP(61) degradation and attenuated p38 activation and cell death in slice models. Furthermore, this peptide was neuroprotective when neurons were subjected to excitotoxicity or cortical slices were exposed to ischemic conditions. These findings suggest a novel mechanism by which differential NMDAR stimulation regulates STEP(61) to promote either ERK1/2 or p38 activation and identifies calpain cleavage of STEP(61) as a valid target for the development of neuroprotective therapy.
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Affiliation(s)
- Jian Xu
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Pradeep Kurup
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Yongfang Zhang
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Susan M. Goebel-Goody
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Peter H. Wu
- Department of Psychiatry, University of Colorado Denver School of Medicine, Aurora, Colorado 80045, and
| | - Ammar H. Hawasli
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Matthew L. Baum
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
| | - James A. Bibb
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Paul J. Lombroso
- The Child Study Center, Yale University School of Medicine, New Haven, Connecticut 06520
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Goebel-Goody S, Davies K, Alvestad Linger R, Freund R, Browning M. Phospho-regulation of synaptic and extrasynaptic N-methyl-d-aspartate receptors in adult hippocampal slices. Neuroscience 2009; 158:1446-59. [DOI: 10.1016/j.neuroscience.2008.11.006] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 11/04/2008] [Accepted: 11/05/2008] [Indexed: 11/25/2022]
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Yip MF, Ramm G, Larance M, Hoehn KL, Wagner MC, Guilhaus M, James DE. CaMKII-mediated phosphorylation of the myosin motor Myo1c is required for insulin-stimulated GLUT4 translocation in adipocytes. Cell Metab 2008; 8:384-98. [PMID: 19046570 DOI: 10.1016/j.cmet.2008.09.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 03/02/2008] [Accepted: 09/19/2008] [Indexed: 11/26/2022]
Abstract
The unconventional myosin Myo1c has been implicated in insulin-regulated GLUT4 translocation to the plasma membrane in adipocytes. We show that Myo1c undergoes insulin-dependent phosphorylation at S701. Phosphorylation was accompanied by enhanced 14-3-3 binding and reduced calmodulin binding. Recombinant CaMKII phosphorylated Myo1c in vitro and siRNA knockdown of CaMKIIdelta abolished insulin-dependent Myo1c phosphorylation in vivo. CaMKII activity was increased upon insulin treatment and the CaMKII inhibitors CN21 and KN-62 or the Ca(2+) chelator BAPTA-AM blocked insulin-dependent Myo1c phosphorylation and insulin-stimulated glucose transport in adipocytes. Myo1c ATPase activity was increased after CaMKII phosphorylation in vitro and after insulin stimulation of CHO/IR/IRS-1 cells. Expression of wild-type Myo1c, but not S701A or ATPase dead mutant K111A, rescued the inhibition of GLUT4 translocation by siRNA-mediated Myo1c knockdown. These data suggest that insulin regulates Myo1c function via CaMKII-dependent phosphorylation, and these events play a role in insulin-regulated GLUT4 trafficking in adipocytes likely involving Myo1c motor activity.
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Affiliation(s)
- Ming Fai Yip
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Darlinghurst, NSW 2010, Australia
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25
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Davies KD, Goebel-Goody SM, Coultrap SJ, Browning MD. Long term synaptic depression that is associated with GluR1 dephosphorylation but not alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor internalization. J Biol Chem 2008; 283:33138-46. [PMID: 18819923 DOI: 10.1074/jbc.m803431200] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Long lasting changes in the strength of synaptic transmission in the hippocampus are thought to underlie certain forms of learning and memory. Accordingly, the molecular mechanisms that account for these changes are heavily studied. Postsynaptically, changes in synaptic strength can occur by altering the amount of neurotransmitter receptors at the synapse or by altering the functional properties of synaptic receptors. In this study, we examined the biochemical changes produced following chemically induced long term depression in acute hippocampal CA1 minislices. Using three independent methods, we found that this treatment did not lead to an internalization of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Furthermore, when the plasma membrane was separated into synaptic membrane-enriched and extrasynaptic membrane-enriched fractions, we actually observed a significant increase in the concentration of AMPA receptors at the synapse. However, phosphorylation of Ser-845 on the AMPA receptor subunit GluR1 was significantly decreased throughout the neuron, including in the synaptic membrane-enriched fraction. In addition, phosphorylation of Ser-831 on GluR1 was decreased specifically in the synaptic membrane-enriched fraction. Phosphorylation of these residues has been demonstrated to control AMPA receptor function. From these data, we conclude that the decrease in synaptic strength is likely the result of a change in the functional properties of AMPA receptors at the synapse and not a decrease in the amount of synaptic receptors.
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Affiliation(s)
- Kurtis D Davies
- Department of Pharmacology, University of Colorado Health Sciences Center, Aurora, Colorado 80045, USA
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Munevar S, Gangopadhyay SS, Gallant C, Colombo B, Sellke FW, Morgan KG. CaMKIIT287 and T305 regulate history-dependent increases in alpha agonist-induced vascular tone. J Cell Mol Med 2007; 12:219-26. [PMID: 18088385 PMCID: PMC3823483 DOI: 10.1111/j.1582-4934.2007.00202.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
CaMKII is a calcium and calmodulin-activated kinase that has been shown to regulate learning and memory in the brain, and contractility in blood vessels. Following Ca activation, CaMKII autophosphorylates, gaining a calcium-independent autonomous activity that reflects a molecular memory of having previously come into contact with calcium. The present study addresses whether the molecular memory properties of CaMKII are involved in the modulation of sustained vascular tone. We demonstrate a history-dependence of α agonist-induced vascular tone and show that CaMKII activation in vascular cells is also history dependent. Autophosphorylation of Thr287, which is classically associated with autonomous activity, does not persist during tone maintenance after transient increases in intracellular calcium levels. However, we have found that another site, Thr305, known from in vitro studies to be inhibitory, is regulated by α agonists in that the inhibitory action is removed, thus leading to a delayed reactivation of CaMKII as measured by Thr287 phosphorylation. By the use of a small molecule CaMKII inhibitor (KN93) as well as a decoy peptide (autoinhibitory peptide; AIP) we show a cause and effect relationship between CaMKII reactivation and sustained vascular tone maintenance. Thus, it appears that a complex interplay between the regulation of Thr305 and Thr287 provides a novel mechanism by which a history-dependence is developed and contributes to a new facet of molecular memory for CaMKII of relevance to vascular tone maintenance.
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Affiliation(s)
- S Munevar
- Boston Biomedical Research Institute, Watertown, MA, USA
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