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Greguske EA, Maroto AF, Borrajo M, Palou A, Gut M, Esteve-Codina A, Barrallo-Gimeno A, Llorens J. Decreased expression of synaptic genes in the vestibular ganglion of rodents following subchronic ototoxic stress. Neurobiol Dis 2023; 182:106134. [PMID: 37100209 DOI: 10.1016/j.nbd.2023.106134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/14/2023] [Accepted: 04/23/2023] [Indexed: 04/28/2023] Open
Abstract
The vestibular ganglion contains primary sensory neurons that are postsynaptic to the transducing hair cells (HC) and project to the central nervous system. Understanding the response of these neurons to HC stress or loss is of great interest as their survival and functional competence will determine the functional outcome of any intervention aiming at repair or regeneration of the HCs. We have shown that subchronic exposure to the ototoxicant 3,3'-iminodipropionitrile (IDPN) in rats and mice causes a reversible detachment and synaptic uncoupling between the HCs and the ganglion neurons. Here, we used this paradigm to study the global changes in gene expression in vestibular ganglia using RNA-seq. Comparative gene ontology and pathway analyses of the data from both model species indicated a robust downregulation of terms related to synapses, including presynaptic and postsynaptic functions. Manual analyses of the most significantly downregulated transcripts identified genes with expressions related to neuronal activity, modulators of neuronal excitability, and transcription factors and receptors that promote neurite growth and differentiation. For choice selected genes, the mRNA expression results were replicated by qRT-PCR, validated spatially by RNA-scope, or were demonstrated to be associated with decreased expression of the corresponding protein. We conjectured that decreased synaptic input or trophic support on the ganglion neurons from the HC was triggering these expression changes. To support this hypothesis, we demonstrated decreased expression of BDNF mRNA in the vestibular epithelium after subchronic ototoxicity and also downregulated expression of similarly identified genes (e.g Etv5, Camk1g, Slc17a6, Nptx2, Spp1) after HC ablation with another ototoxic compound, allylnitrile. We conclude that vestibular ganglion neurons respond to decreased input from HCs by decreasing the strength of all their synaptic contacts, both as postsynaptic and presynaptic players.
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Affiliation(s)
- Erin A Greguske
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain
| | - Alberto F Maroto
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain
| | - Mireia Borrajo
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain.
| | - Aïda Palou
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain.
| | - Marta Gut
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; Universitat Pompeu Fabra, Barcelona, Spain.
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain; Universitat Pompeu Fabra, Barcelona, Spain.
| | - Alejandro Barrallo-Gimeno
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain.
| | - Jordi Llorens
- Departament de Ciències Fisiològiques, Universitat de Barcelona, Feixa Llarga s/n, 08907 l'Hospitalet de Llobregat, Catalunya, Spain; Institut de Neurociènces, Universitat de Barcelona, Barcelona, Catalunya, Spain; Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), 08907 l'Hospitalet de Llobregat, Catalunya, Spain.
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2
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Rodent Models of Audiogenic Epilepsy: Genetic Aspects, Advantages, Current Problems and Perspectives. Biomedicines 2022; 10:biomedicines10112934. [PMID: 36428502 PMCID: PMC9687921 DOI: 10.3390/biomedicines10112934] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/10/2022] [Accepted: 11/11/2022] [Indexed: 11/18/2022] Open
Abstract
Animal models of epilepsy are of great importance in epileptology. They are used to study the mechanisms of epileptogenesis, and search for new genes and regulatory pathways involved in the development of epilepsy as well as screening new antiepileptic drugs. Today, many methods of modeling epilepsy in animals are used, including electroconvulsive, pharmacological in intact animals, and genetic, with the predisposition for spontaneous or refractory epileptic seizures. Due to the simplicity of manipulation and universality, genetic models of audiogenic epilepsy in rodents stand out among this diversity. We tried to combine data on the genetics of audiogenic epilepsy in rodents, the relevance of various models of audiogenic epilepsy to certain epileptic syndromes in humans, and the advantages of using of rodent strains predisposed to audiogenic epilepsy in current epileptology.
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Chuvakova LN, Funikov SY, Rezvykh AP, Davletshin AI, Evgen'ev MB, Litvinova SA, Fedotova IB, Poletaeva II, Garbuz DG. Transcriptome of the Krushinsky-Molodkina Audiogenic Rat Strain and Identification of Possible Audiogenic Epilepsy-Associated Genes. Front Mol Neurosci 2021; 14:738930. [PMID: 34803604 PMCID: PMC8600260 DOI: 10.3389/fnmol.2021.738930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 10/07/2021] [Indexed: 12/13/2022] Open
Abstract
Audiogenic epilepsy (AE), inherent to several rodent strains is widely studied as a model of generalized convulsive epilepsy. The molecular mechanisms that determine the manifestation of AE are not well understood. In the present work, we compared transcriptomes from the corpora quadrigemina in the midbrain zone, which are crucial for AE development, to identify genes associated with the AE phenotype. Three rat strains without sound exposure were compared: Krushinsky-Molodkina (KM) strain (100% AE-prone); Wistar outbred rat strain (non-AE prone) and “0” strain (partially AE-prone), selected from F2 KM × Wistar hybrids for their lack of AE. The findings showed that the KM strain gene expression profile exhibited a number of characteristics that differed from those of the Wistar and “0” strain profiles. In particular, the KM rats showed increased expression of a number of genes involved in the positive regulation of the MAPK signaling cascade and genes involved in the positive regulation of apoptotic processes. Another characteristic of the KM strain which differed from that of the Wistar and “0” rats was a multi-fold increase in the expression level of the Ttr gene and a significant decrease in the expression of the Msh3 gene. Decreased expression of a number of oxidative phosphorylation-related genes and a few other genes was also identified in the KM strain. Our data confirm the complex multigenic nature of AE inheritance in rodents. A comparison with data obtained from other independently selected AE-prone rodent strains suggests some common causes for the formation of the audiogenic phenotype.
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Affiliation(s)
- Lyubov N Chuvakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Sergei Yu Funikov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Alexander P Rezvykh
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, Russia
| | - Artem I Davletshin
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | - Michael B Evgen'ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
| | | | | | | | - David G Garbuz
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, Russia
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ERK1/2 kinases and dopamine D2 receptors participate in the anticonvulsant effects of a new derivative of benzoylpyridine oxime and valproic acid. Eur J Pharmacol 2021; 903:174150. [PMID: 33961874 DOI: 10.1016/j.ejphar.2021.174150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/26/2021] [Accepted: 04/30/2021] [Indexed: 01/11/2023]
Abstract
Inhibition of the activity of extracellular signal-regulated kinases (ERK1/2) induced by the activation of the dopamine D2 receptor signalling cascade may be a promising pharmacological target. The aim of this work was to study the involvement of ERK1/2 and dopamine D2 receptor in the mechanism of the anticonvulsant action of valproic acid (VA) and a new benzoylpyridine oxime derivative (GIZH-298), which showed antiepileptic activity in different models of epilepsy. We showed that subchronic exposure to maximal electroshock seizures (MES) for 5 days reduced the density of dopamine D2 receptors in the striatum of mice. GIZH-298 counteracted the decrease in the number of dopamine D2 receptors associated with MES and increased the number of ligand binding sites of dopamine D2 receptors in mice without MES. The affinity of dopamine D2 receptors to the ligand was not changed by GIZH-298. MES caused an increase in ERK1/2 and synapsin I phosphorylation in the striatum while GIZH-298, similar to VA, reduced the levels of both phospho-ERK1/2 and phosphosynapsin I after MES, which correlated with the decrease in the intensity of seizure in mice. In addition, GIZH-298 suppressed ERK1/2 phosphorylation in SH-SY5Y human neuroblastoma cells at therapeutic concentrations, while VA inhibited ERK1/2 phosphorylation in vivo but not in vitro. The data obtained expand the understanding of the mechanisms of action of VA and GIZH-298, which involve regulating the activity of ERK1/2 kinases, probably by modulating dopamine D2 receptors in limbic structures, as well as (in the case of GIZH-298) directly inhibiting of the ERK1/2 cascade.
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5
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Resilience of network activity in preconditioned neurons exposed to 'stroke-in-a-dish' insults. Neurochem Int 2021; 146:105035. [PMID: 33798645 DOI: 10.1016/j.neuint.2021.105035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 03/20/2021] [Accepted: 03/22/2021] [Indexed: 11/22/2022]
Abstract
Exposing cultured cortical neurons to stimulatory agents - the K+ channel blocker 4-aminopyridine (4-ap), and the GABAA receptor antagonist bicuculline (bic) - for 48 h induces down-regulated synaptic scaling, and preconditions neurons to withstand subsequent otherwise lethal 'stroke-in-a-dish' insults; however, the degree to which usual neuronal function remains is unknown. As a result, multi-electrode array and patch-clamp electrophysiological techniques were employed to characterize hallmarks of spontaneous synaptic activity over a 12-day preconditioning/insult experiment. Spiking frequency increased 8-fold immediately upon 4-ap/bic treatment but declined within the 48 h treatment window to sub-baseline levels that persisted long after washout. Preconditioning resulted in key markers of network activity - spiking frequency, bursting and avalanches - being impervious to an insult. Surprisingly, preconditioning resulted in higher peak NMDA mEPSC amplitudes, resulting in a decrease in the ratio of AMPA:NMDA mEPSC currents, suggesting a relative increase in synaptic NMDA receptors. An investigation of a broad mRNA panel of excitatory and inhibitory signaling mediators indicated preconditioning rapidly up-regulated GABA synthesis (GAD67) and BDNF, followed by up-regulation of neuronal activity-regulated pentraxin and down-regulation of presynaptic glutamate release (VGLUT1). Preconditioning also enhanced surface expression of GLT-1, which persisted following an insult. Overall, preconditioning resulted in a reduced spiking frequency which was impervious to subsequent exposure to 'stroke-in-a-dish' insults, a phenotype initiated predominantly by up-regulation of inhibitory neurotransmission, a lower neuronal postsynaptic AMPA: NMDA receptor ratio, and trafficking of GLT-1 to astrocyte plasma membranes.
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6
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Zhang L, Hernandez VS, Gerfen CR, Jiang SZ, Zavala L, Barrio RA, Eiden LE. Behavioral role of PACAP signaling reflects its selective distribution in glutamatergic and GABAergic neuronal subpopulations. eLife 2021; 10:61718. [PMID: 33463524 PMCID: PMC7875564 DOI: 10.7554/elife.61718] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 01/18/2021] [Indexed: 01/25/2023] Open
Abstract
The neuropeptide PACAP, acting as a co-transmitter, increases neuronal excitability, which may enhance anxiety and arousal associated with threat conveyed by multiple sensory modalities. The distribution of neurons expressing PACAP and its receptor, PAC1, throughout the mouse nervous system was determined, in register with expression of glutamatergic and GABAergic neuronal markers, to develop a coherent chemoanatomical picture of PACAP role in brain motor responses to sensory input. A circuit role for PACAP was tested by observing Fos activation of brain neurons after olfactory threat cue in wild-type and PACAP knockout mice. Neuronal activation and behavioral response, were blunted in PACAP knock-out mice, accompanied by sharply downregulated vesicular transporter expression in both GABAergic and glutamatergic neurons expressing PACAP and its receptor. This report signals a new perspective on the role of neuropeptide signaling in supporting excitatory and inhibitory neurotransmission in the nervous system within functionally coherent polysynaptic circuits.
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Affiliation(s)
- Limei Zhang
- Department of Physiology, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico.,Section on Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, United States
| | - Vito S Hernandez
- Department of Physiology, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Charles R Gerfen
- Laboratory of Systems Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, United States
| | - Sunny Z Jiang
- Section on Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, United States
| | - Lilian Zavala
- Department of Physiology, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Rafael A Barrio
- Section on Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, United States.,Department of Complex Systems, Institute of Physics, National Autonomous University of Mexico (UNAM), Mexico, Mexico
| | - Lee E Eiden
- Section on Molecular Neuroscience, National Institute of Mental Health, Intramural Research Program, Bethesda, United States
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7
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Pietrancosta N, Djibo M, Daumas S, El Mestikawy S, Erickson JD. Molecular, Structural, Functional, and Pharmacological Sites for Vesicular Glutamate Transporter Regulation. Mol Neurobiol 2020; 57:3118-3142. [PMID: 32474835 PMCID: PMC7261050 DOI: 10.1007/s12035-020-01912-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 03/30/2020] [Indexed: 12/11/2022]
Abstract
Vesicular glutamate transporters (VGLUTs) control quantal size of glutamatergic transmission and have been the center of numerous studies over the past two decades. VGLUTs contain two independent transport modes that facilitate glutamate packaging into synaptic vesicles and phosphate (Pi) ion transport into the synaptic terminal. While a transmembrane proton electrical gradient established by a vacuolar-type ATPase powers vesicular glutamate transport, recent studies indicate that binding sites and flux properties for chloride, potassium, and protons within VGLUTs themselves regulate VGLUT activity as well. These intrinsic ionic binding and flux properties of VGLUTs can therefore be modulated by neurophysiological conditions to affect levels of glutamate available for release from synapses. Despite their extraordinary importance, specific and high-affinity pharmacological compounds that interact with these sites and regulate VGLUT function, distinguish between the various modes of transport, and the different isoforms themselves, are lacking. In this review, we provide an overview of the physiologic sites for VGLUT regulation that could modulate glutamate release in an over-active synapse or in a disease state.
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Affiliation(s)
- Nicolas Pietrancosta
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS) INSERM, CNRS, Sorbonne Université, Paris, France. .,Laboratoire des Biomolécules, Sorbonne Université, CNRS, ENS, LBM, 75005, Paris, France.
| | - Mahamadou Djibo
- Sorbonne Paris Cité, Université Paris Descartes, LCBPT, UMR 8601, 75006, Paris, France
| | - Stephanie Daumas
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS) INSERM, CNRS, Sorbonne Université, Paris, France
| | - Salah El Mestikawy
- Neuroscience Paris Seine - Institut de Biologie Paris Seine (NPS - IBPS) INSERM, CNRS, Sorbonne Université, Paris, France. .,Douglas Hospital Research Center, Department of Psychiatry, McGill University, 6875 boulevard Lasalle, Verdun, Montreal, QC, Canada.
| | - Jeffrey D Erickson
- Neuroscience Center, Louisiana State University, New Orleans, LA, 70112, USA. .,Department of Pharmacology, Louisiana State University, New Orleans, LA, 70112, USA.
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8
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Mukerjee S, Gao H, Xu J, Sato R, Zsombok A, Lazartigues E. ACE2 and ADAM17 Interaction Regulates the Activity of Presympathetic Neurons. Hypertension 2019; 74:1181-1191. [PMID: 31564162 DOI: 10.1161/hypertensionaha.119.13133] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Brain renin angiotensin system within the paraventricular nucleus plays a critical role in balancing excitatory and inhibitory inputs to modulate sympathetic output and blood pressure regulation. We previously identified ACE2 and ADAM17 as a compensatory enzyme and a sheddase, respectively, involved in brain renin angiotensin system regulation. Here, we investigated the opposing contribution of ACE2 and ADAM17 to hypothalamic presympathetic activity and ultimately neurogenic hypertension. New mouse models were generated where ACE2 and ADAM17 were selectively knocked down from all neurons (AC-N) or Sim1 neurons (SAT), respectively. Neuronal ACE2 deletion revealed a reduction of inhibitory inputs to AC-N presympathetic neurons relevant to blood pressure regulation. Primary neuron cultures confirmed ACE2 expression on GABAergic neurons synapsing onto excitatory neurons within the hypothalamus but not on glutamatergic neurons. ADAM17 expression was shown to colocalize with angiotensin-II type 1 receptors on Sim1 neurons, and the pressor relevance of this neuronal population was demonstrated by photoactivation. Selective knockdown of ADAM17 was associated with a reduction of FosB gene expression, increased vagal tone, and prevented the acute pressor response to centrally administered angiotensin-II. Chronically, SAT mice exhibited a blunted blood pressure elevation and preserved ACE2 activity during development of salt-sensitive hypertension. Bicuculline injection in those models confirmed the supporting role of ACE2 on GABAergic tone to the paraventricular nucleus. Together, our study demonstrates the contrasting impact of ACE2 and ADAM17 on neuronal excitability of presympathetic neurons within the paraventricular nucleus and the consequences of this mutual regulation in the context of neurogenic hypertension.
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Affiliation(s)
- Snigdha Mukerjee
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans
| | - Hong Gao
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans.,Brain Institute (H.G., A.Z.), Tulane University, New Orleans
| | - Jiaxi Xu
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
| | - Ryosuke Sato
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans
| | - Andrea Zsombok
- Department of Physiology, School of Medicine (H.G., R.S., A.Z.), Tulane University, New Orleans.,Brain Institute (H.G., A.Z.), Tulane University, New Orleans
| | - Eric Lazartigues
- From the Department of Pharmacology and Experimental Therapeutics (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Cardiovascular Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,Neuroscience Center of Excellence (S.M., J.X., E.L.), Louisiana State University Health Sciences Center, New Orleans.,SouthEast Louisiana Veterans Health Care System, New Orleans (J.X., E.L.)
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9
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Page CE, Coutellier L. Prefrontal excitatory/inhibitory balance in stress and emotional disorders: Evidence for over-inhibition. Neurosci Biobehav Rev 2019; 105:39-51. [PMID: 31377218 DOI: 10.1016/j.neubiorev.2019.07.024] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 07/31/2019] [Accepted: 07/31/2019] [Indexed: 01/04/2023]
Abstract
Chronic stress-induced emotional disorders like anxiety and depression involve imbalances between the excitatory glutamatergic system and the inhibitory GABAergic system in the prefrontal cortex (PFC). However, the precise nature and trajectory of excitatory/inhibitory (E/I) imbalances in these conditions is not clear, with the literature reporting glutamatergic and GABAergic findings that are at times contradictory and inconclusive. Here we propose and discuss the hypothesis that chronic stress-induced emotional dysfunction involves hypoactivity of the PFC due to increased inhibition. We will also discuss E/I imbalances in the context of sex differences. In this review, we will synthesize research about how glutamatergic and GABAergic systems are perturbed by chronic stress and in related emotional disorders like anxiety and depression and propose ideas for reconciling contradictory findings in support of the hypothesis of over-inhibition. We will also discuss evidence for how aspects of the GABAergic system such as parvalbumin (PV) cells can be targeted therapeutically for reinstating activity and plasticity in the PFC and treating stress-related disorders.
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Affiliation(s)
- Chloe E Page
- Department of Neuroscience, Ohio State University, Columbus OH, United States
| | - Laurence Coutellier
- Department of Neuroscience, Ohio State University, Columbus OH, United States; Department of Psychology, Ohio State University, Columbus OH, United States.
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10
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Landi S, Petrucco L, Sicca F, Ratto GM. Transient Cognitive Impairment in Epilepsy. Front Mol Neurosci 2019; 11:458. [PMID: 30666185 PMCID: PMC6330286 DOI: 10.3389/fnmol.2018.00458] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 11/28/2018] [Indexed: 02/05/2023] Open
Abstract
Impairments of the dialog between excitation and inhibition (E/I) is commonly associated to neuropsychiatric disorders like autism, bipolar disorders and epilepsy. Moderate levels of hyperexcitability can lead to mild alterations of the EEG and are often associated with cognitive deficits even in the absence of overt seizures. Indeed, various testing paradigms have shown degraded performances in presence of acute or chronic non-ictal epileptiform activity. Evidences from both animal models and the clinics suggest that anomalous activity can cause cognitive deficits by transiently disrupting cortical processing, independently from the underlying etiology of the disease. Here, we will review our understanding of the influence of an abnormal EEG activity on brain computation in the context of the available clinical data and in genetic or pharmacological animal models.
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Affiliation(s)
- Silvia Landi
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Luigi Petrucco
- Graduate School of Systemic Neurosciences, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Federico Sicca
- Department of Developmental Neuroscience, Fondazione IRCCS Stella Maris, Pisa, Italy
| | - Gian Michele Ratto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
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11
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de Bartolomeis A, Buonaguro EF, Latte G, Rossi R, Marmo F, Iasevoli F, Tomasetti C. Immediate-Early Genes Modulation by Antipsychotics: Translational Implications for a Putative Gateway to Drug-Induced Long-Term Brain Changes. Front Behav Neurosci 2017; 11:240. [PMID: 29321734 PMCID: PMC5732183 DOI: 10.3389/fnbeh.2017.00240] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Accepted: 11/22/2017] [Indexed: 12/12/2022] Open
Abstract
An increasing amount of research aims at recognizing the molecular mechanisms involved in long-lasting brain architectural changes induced by antipsychotic treatments. Although both structural and functional modifications have been identified following acute antipsychotic administration in humans, currently there is scarce knowledge on the enduring consequences of these acute changes. New insights in immediate-early genes (IEGs) modulation following acute or chronic antipsychotic administration may help to fill the gap between primary molecular response and putative long-term changes. Moreover, a critical appraisal of the spatial and temporal patterns of IEGs expression may shed light on the functional "signature" of antipsychotics, such as the propensity to induce motor side effects, the potential neurobiological mechanisms underlying the differences between antipsychotics beyond D2 dopamine receptor affinity, as well as the relevant effects of brain region-specificity in their mechanisms of action. The interest for brain IEGs modulation after antipsychotic treatments has been revitalized by breakthrough findings such as the role of early genes in schizophrenia pathophysiology, the involvement of IEGs in epigenetic mechanisms relevant for cognition, and in neuronal mapping by means of IEGs expression profiling. Here we critically review the evidence on the differential modulation of IEGs by antipsychotics, highlighting the association between IEGs expression and neuroplasticity changes in brain regions impacted by antipsychotics, trying to elucidate the molecular mechanisms underpinning the effects of this class of drugs on psychotic, cognitive and behavioral symptoms.
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Affiliation(s)
- Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Elisabetta F Buonaguro
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Gianmarco Latte
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Rodolfo Rossi
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Federica Marmo
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Felice Iasevoli
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
| | - Carmine Tomasetti
- Laboratory of Molecular and Translational Psychiatry and Unit of Treatment Resistant Psychosis, Section of Psychiatry, Department of Neuroscience, Reproductive Sciences and Odontostomatology, University School of Medicine "Federico II", Naples, Italy
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12
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Mitochondrial Calcium Dysregulation Contributes to Dendrite Degeneration Mediated by PD/LBD-Associated LRRK2 Mutants. J Neurosci 2017; 37:11151-11165. [PMID: 29038245 DOI: 10.1523/jneurosci.3791-16.2017] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 10/03/2017] [Accepted: 10/05/2017] [Indexed: 11/21/2022] Open
Abstract
Mutations in leucine-rich repeat kinase 2 (LRRK2) contribute to development of late-onset familial Parkinson's disease (PD), with clinical features of motor and cognitive dysfunction indistinguishable from sporadic PD. Calcium dysregulation plays an important role in PD pathogenesis, but the mechanisms of neurodegeneration remain unclear. Recent reports indicate enhanced excitatory neurotransmission in cortical neurons expressing mutant LRRK2, which occurs before the well-characterized phenotype of dendritic shortening. As mitochondria play a major role in the rapid buffering of cytosolic calcium, we hypothesized that altered mitochondrial calcium handling contributes to dendritic retraction elicited by the LRRK2-G2019S and -R1441C mutations. In primary mouse cortical neurons, we observed increased depolarization-induced mitochondrial calcium uptake. We found that expression of mutant LRRK2 elicited transcriptional upregulation of the mitochondrial calcium uniporter (MCU) and the mitochondrial calcium uptake 1 protein (MICU1) with no change in levels of the mitochondrial calcium antiporter NCLX. Elevated MCU and MICU1 were also observed in LRRK2-mutated patient fibroblasts, along with increased mitochondrial calcium uptake, and in postmortem brains of sporadic PD/PDD patients of both sexes. Transcriptional upregulation of MCU and MICU1 was caused by activation of the ERK1/2 (MAPK3/1) pathway. Inhibiting ERK1/2 conferred protection against mutant LRRK2-induced neurite shortening. Pharmacological inhibitors or RNAi knockdown of MCU attenuated mitochondrial calcium uptake and dendritic/neuritic shortening elicited by mutant LRRK2, whereas expression of a constitutively active mutant of NCLX that enhances calcium export from mitochondria was neuroprotective. These data suggest that an increased susceptibility to mitochondrial calcium dysregulation contributes to dendritic injury in mutant LRRK2 pathogenesis.SIGNIFICANCE STATEMENT Cognitive dysfunction and dementia are common features of Parkinson's disease (PD), causing significant disability. Mutations in LRRK2 represent the most common known genetic cause of PD. We found that PD-linked LRRK2 mutations increased dendritic and mitochondrial calcium uptake in cortical neurons and familial PD patient fibroblasts, accompanied by increased expression of the mitochondrial calcium transporter MCU. Blocking the ERK1/2-dependent upregulation of MCU conferred protection against mutant LRRK2-elicited dendrite shortening, as did inhibiting MCU-mediated calcium import. Conversely, stimulating the export of calcium from mitochondria was also neuroprotective. These results implicate increased susceptibility to mitochondrial calcium overload in LRRK2-driven neurodegeneration, and suggest possible interventions that may slow the progression of cognitive dysfunction in PD.
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Lisek M, Ferenc B, Studzian M, Pulaski L, Guo F, Zylinska L, Boczek T. Glutamate Deregulation in Ketamine-Induced Psychosis-A Potential Role of PSD95, NMDA Receptor and PMCA Interaction. Front Cell Neurosci 2017; 11:181. [PMID: 28701926 PMCID: PMC5487377 DOI: 10.3389/fncel.2017.00181] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 06/13/2017] [Indexed: 12/22/2022] Open
Abstract
Ketamine causes psychotic episodes and is often used as pharmacological model of psychotic-like behavior in animals. There is increasing evidence that molecular mechanism of its action is more complicated than just N-methyl-D-aspartic acid (NMDA) receptor antagonism and involves interaction with the components of calcium homeostatic machinery, in particular plasma membrane calcium pump (PMCA). Therefore, in this study we aimed to characterize brain region-specific effects of ketamine on PMCA activity, interaction with NMDA receptor through postsynaptic density protein 95 (PSD95) scaffolding proteins and glutamate release from nerve endings. In our study, ketamine induced behavioral changes in healthy male rats consistent with psychotic effects. In the same animals, we were able to demonstrate significant inhibition of plasma membrane calcium ATPase (PMCA) activity in cerebellum, hippocampus and striatum. The expression level and isoform composition of PMCAs were also affected in some of these brain compartments, with possible compensatory effects of PMCA1 substituting for decreased expression of PMCA3. Expression of the PDZ domain-containing scaffold protein PSD95 was induced and its association with PMCA4 was higher in most brain compartments upon ketamine treatment. Moreover, increased PSD95/NMDA receptor direct interaction was also reported, strongly suggesting the formation of multiprotein complexes potentially mediating the effect of ketamine on calcium signaling. We further support this molecular mechanism by showing brain region-specific changes in PSD95/PMCA4 spatial colocalization. We also show that ketamine significantly increases synaptic glutamate release in cortex and striatum (without affecting total tissue glutamate content), inducing the expression of vesicular glutamate transporters and decreasing the expression of membrane glutamate reuptake pump excitatory amino acid transporters 2 (EAAT2). Thus, ketamine-mediated PMCA inhibition, by decreasing total Ca2+ clearing potency, may locally raise cytosolic Ca2+ promoting excessive glutamate release. Regional alterations in glutamate secretion can be further driven by PSD95-mediated spatial recruitment of signaling complexes including glutamate receptors and calcium pumps, representing a novel mechanism of psychogenic action of ketamine.
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Affiliation(s)
- Malwina Lisek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical UniversityLodz, Poland
| | - Bozena Ferenc
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical UniversityLodz, Poland
| | - Maciej Studzian
- Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of LodzLodz, Poland
| | - Lukasz Pulaski
- Department of Molecular Biophysics, Faculty of Biology and Environmental Protection, University of LodzLodz, Poland.,Laboratory of Transcriptional Regulation, Institute of Medical BiologyLodz, Poland
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical UniversityShenyang, China
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical UniversityLodz, Poland
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Faculty of Health Sciences, Medical UniversityLodz, Poland.,Boston Children's Hospital and Harvard Medical SchoolBoston, MA, United States
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14
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Tang QP, Shen Q, Wu LX, Feng XL, Liu H, Wu B, Huang XS, Wang GQ, Li ZH, Liu ZJ. STAT3 signal that mediates the neural plasticity is involved in willed-movement training in focal ischemic rats. J Zhejiang Univ Sci B 2017; 17:493-502. [PMID: 27381726 DOI: 10.1631/jzus.b1500297] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Willed-movement training has been demonstrated to be a promising approach to increase motor performance and neural plasticity in ischemic rats. However, little is known regarding the molecular signals that are involved in neural plasticity following willed-movement training. To investigate the potential signals related to neural plasticity following willed-movement training, littermate rats were randomly assigned into three groups: middle cerebral artery occlusion, environmental modification, and willed-movement training. The infarct volume was measured 18 d after occlusion of the right middle cerebral artery. Reverse transcription-polymerase chain reaction (PCR) and immunofluorescence staining were used to detect the changes in the signal transducer and activator of transcription 3 (STAT3) mRNA and protein, respectively. A chromatin immunoprecipitation was used to investigate whether STAT3 bound to plasticity-related genes, such as brain-derived neurotrophic factor (BDNF), synaptophysin, and protein interacting with C kinase 1 (PICK1). In this study, we demonstrated that STAT3 mRNA and protein were markedly increased following 15-d willed-movement training in the ischemic hemispheres of the treated rats. STAT3 bound to BDNF, PICK1, and synaptophysin promoters in the neocortical cells of rats. These data suggest that the increased STAT3 levels after willed-movement training might play critical roles in the neural plasticity by directly regulating plasticity-related genes.
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Affiliation(s)
- Qing-Ping Tang
- Department of Rehabilitation, Brain Hospital of Hunan Province, Hunan University of Chinese Medicine, Changsha 410007, China.,Department of Physiology, School of Basic Medical Sciences, Central South University, Changsha 410078, China
| | - Qin Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Li-Xiang Wu
- Department of Physiology, School of Basic Medical Sciences, Central South University, Changsha 410078, China
| | - Xiang-Ling Feng
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, China
| | - Hui Liu
- Cancer Research Institute, Xiangya School of Medicine, Central South University, Changsha 410078, China
| | - Bei Wu
- Department of Otolaryngology, Xiangya Hospital, Central South University, Changsha 410008, China
| | - Xiao-Song Huang
- Department of Neurology, Brain Hospital of Hunan Province, Hunan University of Chinese Medicine, Changsha 410007, China
| | - Gai-Qing Wang
- Department of Neurology, the Second Hospital, Shanxi Medical University, Taiyuan 030001, China
| | - Zhong-Hao Li
- Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China
| | - Zun-Jing Liu
- Department of Neurology, China-Japan Friendship Hospital, Beijing 100029, China
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15
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Ohgomori T, Yamasaki R, Takeuchi H, Kadomatsu K, Kira JI, Jinno S. Differential involvement of vesicular and glial glutamate transporters around spinal α-motoneurons in the pathogenesis of SOD1 G93A mouse model of amyotrophic lateral sclerosis. Neuroscience 2017; 356:114-124. [PMID: 28526579 DOI: 10.1016/j.neuroscience.2017.05.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/31/2017] [Accepted: 05/08/2017] [Indexed: 12/14/2022]
Abstract
From a view point of the glutamate excitotoxicity theory, several studies have suggested that abnormal glutamate homeostasis via dysfunction of glial glutamate transporter-1 (GLT-1) may underlie neurodegeneration in amyotrophic lateral sclerosis (ALS). However, the detailed role of GLT-1 in the pathogenies of ALS remains controversial. To assess this issue, here we elucidated structural alterations associated with dysregulation of glutamate homeostasis using SOD1G93A mice, a genetic model of familial ALS. We first examined the viability of α-motoneurons in the lumbar spinal cord of SOD1G93A mice. Measurement of the soma size and density indicated that α-motoneurons might be intact at 9weeks of age (presymptomatic stage), then soma shrinkage began at 15weeks of age (progressive stage), and finally neuronal density declined at 21weeks of age (end stage). Next, we carried out the line profile analysis, and found that the coverage of α-motoneurons by GLT-1-positive (GLT-1+) astrocytic processes was decreased only at 21weeks of age, while the reduction of coverage of α-motoneurons by synaptophysin-positive (SYP+) presynaptic terminals began at 15weeks of age. Interestingly, the coverage of α-motoneurons by VGluT2+ presynaptic terminals was transiently increased at 9weeks of age, and then gradually decreased towards 21weeks of age. On the other hand, there were no time-dependent alterations in the coverage of α-motoneurons by GABAergic presynaptic terminals. These findings suggest that VGluT2 and GLT-1 may be differentially involved in the pathogenesis of ALS via abnormal glutamate homeostasis at the presymptomatic stage and end stage of disease, respectively.
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Affiliation(s)
- Tomohiro Ohgomori
- Department of Anatomy and Neuroscience, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Ryo Yamasaki
- Department of Neurology, Neurological Institute, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Hideyuki Takeuchi
- Department of Neuroimmunology, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan; Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama 236-0004, Japan
| | - Kenji Kadomatsu
- Department of Biochemistry, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Jun-Ichi Kira
- Department of Neurology, Neurological Institute, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan
| | - Shozo Jinno
- Department of Anatomy and Neuroscience, Graduate School of Medical Science, Kyushu University, Fukuoka 812-8582, Japan.
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16
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Dorofeeva NA, Nikitina LS, Zosen DV, Glazova MV, Chernigovskaya EV. Functional state of the nigrostriatal system of Krushinsky–Molodkina rats during audiogenic seizure expression. ACTA ACUST UNITED AC 2017. [DOI: 10.1134/s2079059717030029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Stress-altered synaptic plasticity and DAMP signaling in the hippocampus-PFC axis; elucidating the significance of IGF-1/IGF-1R/CaMKIIα expression in neural changes associated with a prolonged exposure therapy. Neuroscience 2017; 353:147-165. [PMID: 28438613 DOI: 10.1016/j.neuroscience.2017.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 12/20/2022]
Abstract
Traumatic stress patients showed significant improvement in behavior after a prolonged exposure to an unrelated stimulus. This treatment method attempts to promote extinction of the fear memory associated with the initial traumatic experience. However, the subsequent prolonged exposure to such stimulus creates an additional layer of neural stress. Although the mechanism remains unclear, prolonged exposure therapy (PET) likely involves changes in synaptic plasticity, neurotransmitter function and inflammation; especially in parts of the brain concerned with the formation and retrieval of fear memory (Hippocampus and Prefrontal Cortex: PFC). Since certain synaptic proteins are also involved in danger-associated molecular pattern signaling (DAMP), we identified the significance of IGF-1/IGF-1R/CaMKIIα expression as a potential link between the concurrent progression of synaptic and inflammatory changes in stress. Thus, a comparison between IGF-1/IGF-1R/CaMKIIα, synaptic and DAMP proteins in stress and PET may highlight the significance of PET on synaptic morphology and neuronal inflammatory response. In behaviorally characterized Sprague-Dawley rats, there was a significant decline in neural IGF-1 (p<0.001), hippocampal (p<0.001) and cortical (p<0.05) IGF-1R expression. These animals showed a significant loss of presynaptic markers (synaptophysin; p<0.001), and changes in neurotransmitters (VGLUT2, Tyrosine hydroxylase, GABA, ChAT). Furthermore, naïve stressed rats recorded a significant decrease in post-synaptic marker (PSD-95; p<0.01) and synaptic regulator (CaMKIIα; p<0.001). As part of the synaptic response to a decrease in brain CaMKIIα, small ion conductance channel (KCa2.2) was upregulated in the brain of naïve stressed rats (p<0.01). After a PET, an increase in IGF-1 (p<0.05) and IGF-1R was recorded in the Stress-PET group (p<0.001). As such, hippocampal (p<0.001), but not cortical (ns) synaptophysin expression increased in Stress-PET. Although PSD-95 was relatively unchanged in the hippocampus and PFC, CaMKIIα (p<0.001) and KCa2.2 (p<0.01) were upregulated in Stress-PET, and may be involved in extinction of fear memory-related synaptic potentials. These changes were also associated with a normalized neurotransmitter function, and a significant reduction in open space avoidance; when the animals were assessed in elevated plus maze (EPM). In addition to a decrease in IGF-1/IGF-1R, an increase in activated hippocampal and cortical microglia was seen in stress (p<0.05) and after a PET (Stress-PET; p<0.001). Furthermore, this was linked with a significant increase in HMGB1 (Hippocampus: p<0.001, PFC: p<0.05) and TLR4 expression (Hippocampus: p<0.01; PFC: ns) in the neurons. Taken together, this study showed that traumatic stress and subsequent PET involves an event-dependent alteration of IGF1/IGF-1R/CaMKIIα. Firstly, we showed a direct relationship between IGF-1/IGF-1R expression, presynaptic function (synaptophysin) and neurotransmitter activity in stress and PET. Secondly, we identified the possible role of CaMKIIα in post-synaptic function and regulation of small ion conductance channels. Lastly, we highlighted some of the possible links between IGF1/IGF-1R/CaMKIIα, the expression of DAMP proteins, Microglia activation, and its implication on synaptic plasticity during stress and PET.
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18
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Nelson SB, Valakh V. Excitatory/Inhibitory Balance and Circuit Homeostasis in Autism Spectrum Disorders. Neuron 2015; 87:684-98. [PMID: 26291155 DOI: 10.1016/j.neuron.2015.07.033] [Citation(s) in RCA: 667] [Impact Index Per Article: 74.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Autism spectrum disorders (ASDs) and related neurological disorders are associated with mutations in many genes affecting the ratio between neuronal excitation and inhibition. However, understanding the impact of these mutations on network activity is complicated by the plasticity of these networks, making it difficult in many cases to separate initial deficits from homeostatic compensation. Here we explore the contrasting evidence for primary defects in inhibition or excitation in ASDs and attempt to integrate the findings in terms of the brain's ability to maintain functional homeostasis.
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Affiliation(s)
- Sacha B Nelson
- Department of Biology and Center for Behavioral Genomics, Brandeis University, 415 South Street, Waltham, MA 02454, USA.
| | - Vera Valakh
- Department of Biology and Center for Behavioral Genomics, Brandeis University, 415 South Street, Waltham, MA 02454, USA
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19
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Glazova MV, Nikitina LS, Hudik KA, Kirillova OD, Dorofeeva NA, Korotkov AA, Chernigovskaya EV. Inhibition of ERK1/2 signaling prevents epileptiform behavior in rats prone to audiogenic seizures. J Neurochem 2014; 132:218-29. [PMID: 25351927 DOI: 10.1111/jnc.12982] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/14/2014] [Accepted: 10/22/2014] [Indexed: 01/24/2023]
Abstract
It has recently been proposed that extracellular signal-regulated kinases 1 and 2 (ERK1/2) are one of the factors mediating seizure development. We hypothesized that inhibition of ERK1/2 activity could prevent audiogenic seizures by altering GABA and glutamate release mechanisms. Krushinsky-Molodkina rats, genetically prone to audiogenic seizure, were recruited in the experiments. Animals were i.p. injected with an inhibitor of ERK1/2 SL 327 at different doses 60 min before audio stimulation. We demonstrated for the first time that inhibition of ERK1/2 activity by SL 327 injections prevented seizure behavior and this effect was dose-dependent and correlated with ERK1/2 activity. The obtained data also demonstrated unchanged levels of GABA production, and an increase in the level of vesicular glutamate transporter 2. The study of exocytosis protein expression showed that SL 327 treatment leads to downregulation of vesicle-associated membrane protein 2 and synapsin I, and accumulation of synaptosomal-associated protein 25 (SNAP-25). The obtained data indicate that the inhibition of ERK1/2 blocks seizure behavior presumably by altering the exocytosis machinery, and identifies ERK1/2 as a potential target for the development of new strategies for seizure treatment. Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are one of the factors mediating seizure development. Here we report that inhibition of ERK1/2 by SL 327 prevented seizure behavior and this effect was dose-dependent and correlated with ERK1/2 activity. Accumulation of VGLUT2 was associated with differential changing of synaptic proteins VAMP2, SNAP-25 and synapsin I. The obtained data indicate that the inhibition of ERK1/2 alters neurotransmitter release by changing the exocytosis machinery, thus preventing seizures.
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Affiliation(s)
- Margarita V Glazova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint-Petersburg, Russia
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20
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Zheng H, Stornetta RL, Agassandian K, Rinaman L. Glutamatergic phenotype of glucagon-like peptide 1 neurons in the caudal nucleus of the solitary tract in rats. Brain Struct Funct 2014; 220:3011-22. [PMID: 25012114 DOI: 10.1007/s00429-014-0841-6] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Accepted: 07/02/2014] [Indexed: 01/30/2023]
Abstract
The expression of a vesicular glutamate transporter (VGLUT) suffices to assign a glutamatergic phenotype to neurons and other secretory cells. For example, intestinal L cells express VGLUT2 and secrete glutamate along with glucagon-like peptide 1 (GLP1). We hypothesized that GLP1-positive neurons within the caudal (visceral) nucleus of the solitary tract (cNST) also are glutamatergic. To test this, the axonal projections of GLP1 and other neurons within the cNST were labeled in rats via iontophoretic delivery of anterograde tracer. Dual immunofluorescence and confocal microscopy was used to visualize tracer-, GLP1-, and VGLUT2-positive fibers within brainstem, hypothalamic, and limbic forebrain nuclei that receive input from the cNST. Electron microscopy was used to confirm GLP1 and VGLUT2 immunolabeling within the same axon varicosities, and fluorescent in situ hybridization was used to examine VGLUT2 mRNA expression by GLP1-positive neurons. Most anterograde tracer-labeled fibers displayed VGLUT2-positive varicosities, providing new evidence that ascending axonal projections from the cNST are primarily glutamatergic. Virtually all GLP1-positive varicosities also were VGLUT2-positive. Electron microscopy confirmed the colocalization of GLP1 and VGLUT2 immunolabeling in axon terminals that formed asymmetric (excitatory-type) synapses with unlabeled dendrites in the hypothalamus. Finally, in situ hybridization confirmed that GLP1-positive cNST neurons express VGLUT2 mRNA. Thus, hindbrain GLP1 neurons in rats are equipped to store glutamate in synaptic vesicles, and likely co-release both glutamate and GLP1 from axon varicosities and terminals in the hypothalamus and other brain regions.
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Affiliation(s)
- H Zheng
- Department of Neuroscience, University of Pittsburgh, A210 Langley Hall, Pittsburgh, PA, 15260, USA
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21
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Vallès A, Granic I, De Weerd P, Martens GJM. Molecular correlates of cortical network modulation by long-term sensory experience in the adult rat barrel cortex. Learn Mem 2014; 21:305-10. [PMID: 25171421 PMCID: PMC4024621 DOI: 10.1101/lm.034827.114] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Modulation of cortical network connectivity is crucial for an adaptive response to experience. In the rat barrel cortex, long-term sensory stimulation induces cortical network modifications and neuronal response changes of which the molecular basis is unknown. Here, we show that long-term somatosensory stimulation by enriched environment up-regulates cortical expression of neuropeptide mRNAs and down-regulates immediate-early gene (IEG) mRNAs specifically in the barrel cortex, and not in other brain regions. The present data suggest a central role of neuropeptides in the fine-tuning of sensory cortical circuits by long-term experience.
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Affiliation(s)
- Astrid Vallès
- Department of Neurocognition, Faculty of Psychology and Neuroscience, Maastricht University, 6229 EV Maastricht, The Netherlands Department of Molecular Animal Physiology, Radboud University, Donders Institute for Brain, Cognition and Behaviour (Centre for Neuroscience), Nijmegen Centre for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
| | - Ivica Granic
- Department of Neurocognition, Faculty of Psychology and Neuroscience, Maastricht University, 6229 EV Maastricht, The Netherlands Department of Molecular Animal Physiology, Radboud University, Donders Institute for Brain, Cognition and Behaviour (Centre for Neuroscience), Nijmegen Centre for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
| | - Peter De Weerd
- Department of Neurocognition, Faculty of Psychology and Neuroscience, Maastricht University, 6229 EV Maastricht, The Netherlands Department of Molecular Animal Physiology, Radboud University, Donders Institute for Brain, Cognition and Behaviour (Centre for Neuroscience), Nijmegen Centre for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
| | - Gerard J M Martens
- Department of Molecular Animal Physiology, Radboud University, Donders Institute for Brain, Cognition and Behaviour (Centre for Neuroscience), Nijmegen Centre for Molecular Life Sciences, 6525 GA Nijmegen, The Netherlands
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22
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Lindsly C, Gonzalez-Islas C, Wenner P. Activity blockade and GABAA receptor blockade produce synaptic scaling through chloride accumulation in embryonic spinal motoneurons and interneurons. PLoS One 2014; 9:e94559. [PMID: 24733046 PMCID: PMC3986094 DOI: 10.1371/journal.pone.0094559] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/18/2014] [Indexed: 12/03/2022] Open
Abstract
Synaptic scaling represents a process whereby the distribution of a cell's synaptic strengths are altered by a multiplicative scaling factor. Scaling is thought to be a compensatory response that homeostatically controls spiking activity levels in the cell or network. Previously, we observed GABAergic synaptic scaling in embryonic spinal motoneurons following in vivo blockade of either spiking activity or GABAA receptors (GABAARs). We had determined that activity blockade triggered upward GABAergic scaling through chloride accumulation, thus increasing the driving force for these currents. To determine whether chloride accumulation also underlies GABAergic scaling following GABAAR blockade we have developed a new technique. We expressed a genetically encoded chloride-indicator, Clomeleon, in the embryonic chick spinal cord, which provides a non-invasive fast measure of intracellular chloride. Using this technique we now show that chloride accumulation underlies GABAergic scaling following blockade of either spiking activity or the GABAAR. The finding that GABAAR blockade and activity blockade trigger scaling via a common mechanism supports our hypothesis that activity blockade reduces GABAAR activation, which triggers synaptic scaling. In addition, Clomeleon imaging demonstrated the time course and widespread nature of GABAergic scaling through chloride accumulation, as it was also observed in spinal interneurons. This suggests that homeostatic scaling via chloride accumulation is a common feature in many neuronal classes within the embryonic spinal cord and opens the possibility that this process may occur throughout the nervous system at early stages of development.
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Affiliation(s)
- Casie Lindsly
- Physiology Department, Emory University, School of Medicine, Atlanta, Georgia, United States of America
| | - Carlos Gonzalez-Islas
- Physiology Department, Emory University, School of Medicine, Atlanta, Georgia, United States of America
| | - Peter Wenner
- Physiology Department, Emory University, School of Medicine, Atlanta, Georgia, United States of America
- * E-mail:
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23
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Frank CA. How voltage-gated calcium channels gate forms of homeostatic synaptic plasticity. Front Cell Neurosci 2014; 8:40. [PMID: 24592212 PMCID: PMC3924756 DOI: 10.3389/fncel.2014.00040] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Accepted: 01/28/2014] [Indexed: 01/15/2023] Open
Abstract
Throughout life, animals face a variety of challenges such as developmental growth, the presence of toxins, or changes in temperature. Neuronal circuits and synapses respond to challenges by executing an array of neuroplasticity paradigms. Some paradigms allow neurons to up- or downregulate activity outputs, while countervailing ones ensure that outputs remain within appropriate physiological ranges. A growing body of evidence suggests that homeostatic synaptic plasticity (HSP) is critical in the latter case. Voltage-gated calcium channels gate forms of HSP. Presynaptically, the aggregate data show that when synapse activity is weakened, homeostatic signaling systems can act to correct impairments, in part by increasing calcium influx through presynaptic CaV2-type channels. Increased calcium influx is often accompanied by parallel increases in the size of active zones and the size of the readily releasable pool of presynaptic vesicles. These changes coincide with homeostatic enhancements of neurotransmitter release. Postsynaptically, there is a great deal of evidence that reduced network activity and loss of calcium influx through CaV1-type calcium channels also results in adaptive homeostatic signaling. Some adaptations drive presynaptic enhancements of vesicle pool size and turnover rate via retrograde signaling, as well as de novo insertion of postsynaptic neurotransmitter receptors. Enhanced calcium influx through CaV1 after network activation or single cell stimulation can elicit the opposite response-homeostatic depression via removal of excitatory receptors. There exist intriguing links between HSP and calcium channelopathies-such as forms of epilepsy, migraine, ataxia, and myasthenia. The episodic nature of some of these disorders suggests alternating periods of stable and unstable function. Uncovering information about how calcium channels are regulated in the context of HSP could be relevant toward understanding these and other disorders.
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Affiliation(s)
- C Andrew Frank
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine Iowa City, IA, USA
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24
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Lazarevic V, Pothula S, Andres-Alonso M, Fejtova A. Molecular mechanisms driving homeostatic plasticity of neurotransmitter release. Front Cell Neurosci 2013; 7:244. [PMID: 24348337 PMCID: PMC3847662 DOI: 10.3389/fncel.2013.00244] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 11/18/2013] [Indexed: 12/27/2022] Open
Abstract
Homeostatic plasticity is a process by which neurons adapt to the overall network activity to keep their firing rates in a reasonable range. At the cellular level this kind of plasticity comprises modulation of cellular excitability and tuning of synaptic strength. In this review we concentrate on presynaptic homeostatic plasticity controlling the efficacy of neurotransmitter release from presynaptic boutons. While morphological and electrophysiological approaches were successful to describe homeostatic plasticity-induced changes in the presynaptic architecture and function, cellular and molecular mechanisms underlying those modifications remained largely unknown for a long time. We summarize the latest progress made in the understanding of homeostasis-induced regulation of different steps of the synaptic vesicle cycle and the molecular machineries involved in this process. We particularly focus on the role of presynaptic scaffolding proteins, which functionally and spatially organize synaptic vesicle clusters, neurotransmitter release sites and the associated endocytic machinery. These proteins turned out to be major presynaptic substrates for remodeling during homeostatic plasticity. Finally, we discuss cellular processes and signaling pathways acting during homeostatic molecular remodeling and their potential involvement in the maladaptive plasticity occurring in multiple neuropathologic conditions such as neurodegeneration, epilepsy and neuropsychiatric disorders.
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Affiliation(s)
- Vesna Lazarevic
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology Magdeburg, Germany
| | - Santosh Pothula
- Research Group Presynaptic Plasticity, Leibniz Institute for Neurobiology Magdeburg, Germany
| | - Maria Andres-Alonso
- Research Group Presynaptic Plasticity, Leibniz Institute for Neurobiology Magdeburg, Germany
| | - Anna Fejtova
- Research Group Presynaptic Plasticity, Leibniz Institute for Neurobiology Magdeburg, Germany ; Center for Behavioral Brain Sciences Magdeburg, Germany
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Wairkar YP, Trivedi D, Natarajan R, Barnes K, Dolores L, Cho P. CK2α regulates the transcription of BRP in Drosophila. Dev Biol 2013; 384:53-64. [PMID: 24080510 DOI: 10.1016/j.ydbio.2013.09.025] [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: 04/04/2013] [Revised: 09/18/2013] [Accepted: 09/20/2013] [Indexed: 01/26/2023]
Abstract
Development and plasticity of synapses are brought about by a complex interplay between various signaling pathways. Typically, either changing the number of synapses or strengthening an existing synapse can lead to changes during synaptic plasticity. Altering the machinery that governs the exocytosis of synaptic vesicles, which primarily fuse at specialized structures known as active zones on the presynaptic terminal, brings about these changes. Although signaling pathways that regulate the synaptic plasticity from the postsynaptic compartments are well defined, the pathways that control these changes presynaptically are poorly described. In a genetic screen for synapse development in Drosophila, we found that mutations in CK2α lead to an increase in the levels of Bruchpilot (BRP), a scaffolding protein associated with the active zones. Using a combination of genetic and biochemical approaches, we found that the increase in BRP in CK2α mutants is largely due to an increase in the transcription of BRP. Interestingly, the transcripts of other active zone proteins that are important for function of active zones were also increased, while the transcripts from some other synaptic proteins were unchanged. Thus, our data suggest that CK2α might be important in regulating synaptic plasticity by modulating the transcription of BRP. Hence, we propose that CK2α is a novel regulator of the active zone protein, BRP, in Drosophila.
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Affiliation(s)
- Yogesh P Wairkar
- Department of Neurology, Mitchell Center for Neurodegenerative Diseases, University of Texas Medical Branch, 301 University Blvd., Rte#1045, Galveston, TX 77555, United States.
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Neurodevelopmental role for VGLUT2 in pyramidal neuron plasticity, dendritic refinement, and in spatial learning. J Neurosci 2013; 32:15886-901. [PMID: 23136427 DOI: 10.1523/jneurosci.4505-11.2012] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The level and integrity of glutamate transmission during critical periods of postnatal development plays an important role in the refinement of pyramidal neuron dendritic arbor, synaptic plasticity, and cognition. Presently, it is not clear how excitatory transmission via the two predominant isoforms of the vesicular glutamate transporter (VGLUT1 and VGLUT2) participate in this process. To assess a neurodevelopmental role for VGLUT2 in pyramidal neuron maturation, we generated recombinant VGLUT2 knock-out mice and inactivated VGLUT2 throughout development using Emx1-Cre(+/+) knock-in mice. We show that VGLUT2 deficiency in corticolimbic circuits results in reduced evoked glutamate transmission, release probability, and LTD at hippocampal CA3-CA1 synapses during a formative developmental period (postnatal days 11-14). In adults, we find a marked reduction in the amount of dendritic arbor across the span of the dendritic tree of CA1 pyramidal neurons and reduced long-term potentiation and levels of synaptic markers spinophilin and VGLUT1. Loss of dendritic arbor is accompanied by corresponding reductions in the number of dendritic spines, suggesting widespread alterations in synaptic connectivity. Conditional VGLUT2 knock-out mice exhibit increased open-field exploratory activity yet impaired spatial learning and memory, endophenotypes similar to those of NMDA receptor knock-down mice. Remarkably, the impairment in learning can be partially restored by selectively increasing NMDA receptor-mediated glutamate transmission in adult mice by prolonged treatment with d-serine and a d-amino acid oxidase inhibitor. Our data indicate that VGLUT2 expression is pivotal to the proper development of mature pyramidal neuronal architecture and plasticity, and that such glutamatergic deficiency leads to cognitive malfunction as observed in several neurodevelopmental psychiatric disorders.
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Koltsova SV, Trushina Y, Haloui M, Akimova OA, Tremblay J, Hamet P, Orlov SN. Ubiquitous [Na+]i/[K+]i-sensitive transcriptome in mammalian cells: evidence for Ca(2+)i-independent excitation-transcription coupling. PLoS One 2012; 7:e38032. [PMID: 22666440 PMCID: PMC3362528 DOI: 10.1371/journal.pone.0038032] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/29/2012] [Indexed: 12/21/2022] Open
Abstract
Stimulus-dependent elevation of intracellular Ca2+ ([Ca2+]i) affects the expression of numerous genes – a phenomenon known as excitation-transcription coupling. Recently, we found that increases in [Na+]i trigger c-Fos expression via a novel Ca2+i-independent pathway. In the present study, we identified ubiquitous and tissue-specific [Na+]i/[K+]i-sensitive transcriptomes by comparative analysis of differentially expressed genes in vascular smooth muscle cells from rat aorta (RVSMC), the human adenocarcinoma cell line HeLa, and human umbilical vein endothelial cells (HUVEC). To augment [Na+]i and reduce [K+]i, cells were treated for 3 hrs with the Na+,K+-ATPase inhibitor ouabain or placed for the same time in the K+-free medium. Employing Affymetrix-based technology, we detected changes in expression levels of 684, 737 and 1839 transcripts in HeLa, HUVEC and RVSMC, respectively, that were highly correlated between two treatments (p<0.0001; R2>0.62). Among these Na+i/K+i-sensitive genes, 80 transcripts were common for all three types of cells. To establish if changes in gene expression are dependent on increases in [Ca2+]i, we performed identical experiments in Ca2+-free media supplemented with extracellular and intracellular Ca2+ chelators. Surprisingly, this procedure elevated rather than decreased the number of ubiquitous and cell-type specific Na+i/K+i-sensitive genes. Among the ubiquitous Na+i/K+i-sensitive genes whose expression was regulated independently of the presence of Ca2+ chelators by more than 3-fold, we discovered several transcription factors (Fos, Jun, Hes1, Nfkbia), interleukin-6, protein phosphatase 1 regulatory subunit, dual specificity phosphatase (Dusp8), prostaglandin-endoperoxide synthase 2, cyclin L1, whereas expression of metallopeptidase Adamts1, adrenomedulin, Dups1, Dusp10 and Dusp16 was detected exclusively in Ca2+-depleted cells. Overall, our findings indicate that Ca2+i-independent mechanisms of excitation-transcription coupling are involved in transcriptomic alterations triggered by elevation of the [Na+]i/[K+]i ratio. There results likely have profound implications for normal and pathological regulation of mammalian cells, including sustained excitation of neuronal cells, intensive exercise and ischemia-triggered disorders.
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Affiliation(s)
- Svetlana V. Koltsova
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) – Technopôle Angus, Montreal, PQ, Canada
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia
| | - Yulia Trushina
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Mounsif Haloui
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) – Technopôle Angus, Montreal, PQ, Canada
| | - Olga A. Akimova
- Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow, Russia
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow, Russia
| | - Johanne Tremblay
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) – Technopôle Angus, Montreal, PQ, Canada
- Department of Medicine, Université de Montréal, Montreal, PQ, Canada
| | - Pavel Hamet
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) – Technopôle Angus, Montreal, PQ, Canada
- Department of Medicine, Université de Montréal, Montreal, PQ, Canada
| | - Sergei N. Orlov
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM) – Technopôle Angus, Montreal, PQ, Canada
- Department of Medicine, Université de Montréal, Montreal, PQ, Canada
- * E-mail:
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Dopamine D1-D2 receptor heteromer in dual phenotype GABA/glutamate-coexpressing striatal medium spiny neurons: regulation of BDNF, GAD67 and VGLUT1/2. PLoS One 2012; 7:e33348. [PMID: 22428025 PMCID: PMC3299775 DOI: 10.1371/journal.pone.0033348] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 02/13/2012] [Indexed: 12/15/2022] Open
Abstract
In basal ganglia a significant subset of GABAergic medium spiny neurons (MSNs) coexpress D1 and D2 receptors (D1R and D2R) along with the neuropeptides dynorphin (DYN) and enkephalin (ENK). These coexpressing neurons have been recently shown to have a region-specific distribution throughout the mesolimbic and basal ganglia circuits. While the functional relevance of these MSNs remains relatively unexplored, they have been shown to exhibit the unique property of expressing the dopamine D1–D2 receptor heteromer, a novel receptor complex with distinct pharmacology and cell signaling properties. Here we showed that MSNs coexpressing the D1R and D2R also exhibited a dual GABA/glutamate phenotype. Activation of the D1R–D2R heteromer in these neurons resulted in the simultaneous, but differential regulation of proteins involved in GABA and glutamate production or vesicular uptake in the nucleus accumbens (NAc), ventral tegmental area (VTA), caudate putamen and substantia nigra (SN). Additionally, activation of the D1R–D2R heteromer in NAc shell, but not NAc core, differentially altered protein expression in VTA and SN, regions rich in dopamine cell bodies. The identification of a MSN with dual inhibitory and excitatory intrinsic functions provides new insights into the neuroanatomy of the basal ganglia and demonstrates a novel source of glutamate in this circuit. Furthermore, the demonstration of a dopamine receptor complex with the potential to differentially regulate the expression of proteins directly involved in GABAergic inhibitory or glutamatergic excitatory activation in VTA and SN may potentially provide new insights into the regulation of dopamine neuron activity. This could have broad implications in understanding how dysregulation of neurotransmission within basal ganglia contributes to dopamine neuronal dysfunction.
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Delgado JY, Owens GC. The cytochrome c gene proximal enhancer drives activity-dependent reporter gene expression in hippocampal neurons. Front Mol Neurosci 2012; 5:31. [PMID: 22408605 PMCID: PMC3296065 DOI: 10.3389/fnmol.2012.00031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Accepted: 02/22/2012] [Indexed: 01/29/2023] Open
Abstract
The proximal enhancer of the cytochrome c gene (Cycs) contains binding sites for both cAMP response element binding proteins (CREB) and Nuclear Respiratory Factor 1 (NRF1). To investigate how neuronal activity regulates this enhancer region, a lentivirus was constructed in which a short-lived green fluorescent protein (GFP) was placed under the transcriptional control of the Cycs proximal enhancer linked to a synthetic core promoter. Primary hippocampal neurons were infected, and the synaptic strengths of individual neurons were measured by whole-cell patch clamping. On average the amplitude of miniature postsynaptic currents (mEPSCs) was higher in brighter GFP+ neurons, while the frequency of mEPSCs was not significantly different. Increasing neural activity by applying a GABAA receptor antagonist increased GFP expression in most neurons, which persisted after homeostatic synaptic scaling as evidenced by a decrease in the amplitude and frequency of mEPSCs. Removing the CREB binding sites revealed that calcium influx through L-type channels and NMDA receptors, and ERK1/2 activation played a role in NRF1-mediated transcription. CREB and NRF1, therefore, combine to regulate transcription of Cycs in response to changing neural activity.
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Affiliation(s)
- Jary Y Delgado
- The Neurosciences Institute, 10640 John Jay Hopkins Drive, San Diego CA, USA
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30
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Modulation of CREB in the dorsal lateral geniculate nucleus of dark-reared mice. Neural Plast 2012; 2012:426437. [PMID: 22292123 PMCID: PMC3265102 DOI: 10.1155/2012/426437] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Accepted: 10/04/2011] [Indexed: 11/18/2022] Open
Abstract
The cAMP-response element-binding protein (CREB) plays an important role in visual cortical plasticity that follows the disruption of sensory activity, as induced by dark rearing (DR). Recent findings indicate that the dorsal lateral geniculate nucleus (dLGN) of thalamus is also sensitive to altered sensory activity. DR disrupts retinogeniculate synaptic strength and pruning in mice, but only when DR starts one week after eye opening (delayed DR, DDR) and not after chronic DR (CDR) from birth. While DR upregulates CREB in visual cortex, whether it also modulates this pathway in dLGN remains unknown. Here we investigate the role of CREB in the dLGN of mice that were CDR or DDR using western blot and immunofluorescence. Similar to findings in visual cortex, CREB is upregulated in dLGN after CDR and DDR. These findings are consistent with the proposal that DR up-regulates the CREB pathway in response to decreased visual drive.
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Mechanisms of GABAergic homeostatic plasticity. Neural Plast 2011; 2011:489470. [PMID: 21876819 PMCID: PMC3159121 DOI: 10.1155/2011/489470] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Accepted: 04/25/2011] [Indexed: 01/16/2023] Open
Abstract
Homeostatic plasticity ensures that appropriate levels of activity are maintained through compensatory adjustments in synaptic strength and cellular excitability. For instance, excitatory glutamatergic synapses are strengthened following activity blockade and weakened following increases in spiking activity. This form of plasticity has been described in a wide array of networks at several different stages of development, but most work and reviews have focussed on the excitatory inputs of excitatory neurons. Here we review homeostatic plasticity of GABAergic neurons and their synaptic connections. We propose a simplistic model for homeostatic plasticity of GABAergic components of the circuitry (GABAergic synapses onto excitatory neurons, excitatory connections onto GABAergic neurons, cellular excitability of GABAergic neurons): following chronic activity blockade there is a weakening of GABAergic inhibition, and following chronic increases in network activity there is a strengthening of GABAergic inhibition. Previous work on GABAergic homeostatic plasticity supports certain aspects of the model, but it is clear that the model cannot fully account for some results which do not appear to fit any simplistic rule. We consider potential reasons for these discrepancies.
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32
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Blaylock RL, Maroon J. Immunoexcitotoxicity as a central mechanism in chronic traumatic encephalopathy-A unifying hypothesis. Surg Neurol Int 2011; 2:107. [PMID: 21886880 PMCID: PMC3157093 DOI: 10.4103/2152-7806.83391] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 06/06/2011] [Indexed: 12/17/2022] Open
Abstract
Some individuals suffering from mild traumatic brain injuries, especially repetitive mild concussions, are thought to develop a slowly progressive encephalopathy characterized by a number of the neuropathological elements shared with various neurodegenerative diseases. A central pathological mechanism explaining the development of progressive neurodegeneration in this subset of individuals has not been elucidated. Yet, a large number of studies indicate that a process called immunoexcitotoxicity may be playing a central role in many neurodegenerative diseases including chronic traumatic encephalopathy (CTE). The term immunoexcitotoxicity was first coined by the lead author to explain the evolving pathological and neurodevelopmental changes in autism and the Gulf War Syndrome, but it can be applied to a number of neurodegenerative disorders. The interaction between immune receptors within the central nervous system (CNS) and excitatory glutamate receptors trigger a series of events, such as extensive reactive oxygen species/reactive nitrogen species generation, accumulation of lipid peroxidation products, and prostaglandin activation, which then leads to dendritic retraction, synaptic injury, damage to microtubules, and mitochondrial suppression. In this paper, we discuss the mechanism of immunoexcitotoxicity and its link to each of the pathophysiological and neurochemical events previously described with CTE, with special emphasis on the observed accumulation of hyperphosphorylated tau.
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Affiliation(s)
- Russell L Blaylock
- Theoretical Neurosciences, LLC Visiting Professor of Biology, Belhaven University, Jackson, MS 315 Rolling Meadows Rd, Ridgeland, MS 39157, USA
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Jeon SJ, Rhee SY, Seo JE, Bak HR, Lee SH, Ryu JH, Cheong JH, Shin CY, Kim GH, Lee YS, Ko KH. Oroxylin A increases BDNF production by activation of MAPK–CREB pathway in rat primary cortical neuronal culture. Neurosci Res 2011; 69:214-22. [DOI: 10.1016/j.neures.2010.11.008] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 11/25/2010] [Accepted: 11/30/2010] [Indexed: 01/12/2023]
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Narp regulates homeostatic scaling of excitatory synapses on parvalbumin-expressing interneurons. Nat Neurosci 2010; 13:1090-7. [PMID: 20729843 PMCID: PMC2949072 DOI: 10.1038/nn.2621] [Citation(s) in RCA: 208] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Accepted: 07/22/2010] [Indexed: 01/22/2023]
Abstract
Homeostatic synaptic scaling alters the strength of synapses to compensate for prolonged changes in network activity, and involves both excitatory and inhibitory neurons. The immediate-early gene termed Narp (Neuronal activity-regulated pentraxin) encodes a secreted synaptic protein that can bind and cluster AMPA receptors (AMPARs). Here, we report that Narp prominently accumulates at excitatory synapses on Parvalbumin-expressing interneurons (PV-INs). Increasing network activity results in a homeostatic increase of excitatory synaptic strength onto PV-INs that increases inhibitory drive, and this response is absent in neurons cultured from Narp knock-out (Narp−/−) mice. Activity-dependent changes in the strength of excitatory inputs on PV-INs in acute hippocampal slices are also dependent on Narp, and Narp−/− mice display increased sensitivity to kindling-induced seizures. We propose that Narp recruits AMPARs at excitatory synapses onto PV-INs to rebalance network excitation/inhibition dynamics following episodes of increased circuit activity.
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