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Ojanen S, Kuznetsova T, Kharybina Z, Voikar V, Lauri SE, Taira T. Interneuronal GluK1 kainate receptors control maturation of GABAergic transmission and network synchrony in the hippocampus. Mol Brain 2023; 16:43. [PMID: 37210550 DOI: 10.1186/s13041-023-01035-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 05/07/2023] [Indexed: 05/22/2023] Open
Abstract
Kainate type glutamate receptors (KARs) are strongly expressed in GABAergic interneurons and have the capability of modulating their functions via ionotropic and G-protein coupled mechanisms. GABAergic interneurons are critical for generation of coordinated network activity in both neonatal and adult brain, yet the role of interneuronal KARs in network synchronization remains unclear. Here, we show that GABAergic neurotransmission and spontaneous network activity is perturbed in the hippocampus of neonatal mice lacking GluK1 KARs selectively in GABAergic neurons. Endogenous activity of interneuronal GluK1 KARs maintains the frequency and duration of spontaneous neonatal network bursts and restrains their propagation through the hippocampal network. In adult male mice, the absence of GluK1 in GABAergic neurons led to stronger hippocampal gamma oscillations and enhanced theta-gamma cross frequency coupling, coinciding with faster spatial relearning in the Barnes maze. In females, loss of interneuronal GluK1 resulted in shorter sharp wave ripple oscillations and slightly impaired abilities in flexible sequencing task. In addition, ablation of interneuronal GluK1 resulted in lower general activity and novel object avoidance, while causing only minor anxiety phenotype. These data indicate a critical role for GluK1 containing KARs in GABAergic interneurons in regulation of physiological network dynamics in the hippocampus at different stages of development.
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Affiliation(s)
- Simo Ojanen
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- HiLife Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Tatiana Kuznetsova
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
| | - Zoia Kharybina
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland
- HiLife Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Vootele Voikar
- HiLife Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Sari E Lauri
- HiLife Neuroscience Center, University of Helsinki, Helsinki, Finland.
- Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland.
| | - Tomi Taira
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
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2
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Sainio MT, Rasila T, Molchanova SM, Järvilehto J, Torregrosa-Muñumer R, Harjuhaahto S, Pennonen J, Huber N, Herukka SK, Haapasalo A, Zetterberg H, Taira T, Palmio J, Ylikallio E, Tyynismaa H. Neurofilament Light Regulates Axon Caliber, Synaptic Activity, and Organelle Trafficking in Cultured Human Motor Neurons. Front Cell Dev Biol 2022; 9:820105. [PMID: 35237613 PMCID: PMC8883324 DOI: 10.3389/fcell.2021.820105] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/28/2021] [Indexed: 11/27/2022] Open
Abstract
Neurofilament light (NFL) is one of the proteins forming multimeric neuron-specific intermediate filaments, neurofilaments, which fill the axonal cytoplasm, establish caliber growth, and provide structural support. Dominant missense mutations and recessive nonsense mutations in the neurofilament light gene (NEFL) are among the causes of Charcot-Marie-Tooth (CMT) neuropathy, which affects the peripheral nerves with the longest axons. We previously demonstrated that a neuropathy-causing homozygous nonsense mutation in NEFL led to the absence of NFL in patient-specific neurons. To understand the disease-causing mechanisms, we investigate here the functional effects of NFL loss in human motor neurons differentiated from induced pluripotent stem cells (iPSC). We used genome editing to generate NEFL knockouts and compared them to patient-specific nonsense mutants and isogenic controls. iPSC lacking NFL differentiated efficiently into motor neurons with normal axon growth and regrowth after mechanical axotomy and contained neurofilaments. Electrophysiological analysis revealed that motor neurons without NFL fired spontaneous and evoked action potentials with similar characteristics as controls. However, we found that, in the absence of NFL, human motor neurons 1) had reduced axonal caliber, 2) the amplitude of miniature excitatory postsynaptic currents (mEPSC) was decreased, 3) neurofilament heavy (NFH) levels were reduced and no compensatory increases in other filament subunits were observed, and 4) the movement of mitochondria and to a lesser extent lysosomes was increased. Our findings elaborate the functional roles of NFL in human motor neurons. NFL is not only a structural protein forming neurofilaments and filling the axonal cytoplasm, but our study supports the role of NFL in the regulation of synaptic transmission and organelle trafficking. To rescue the NFL deficiency in the patient-specific nonsense mutant motor neurons, we used three drugs, amlexanox, ataluren (PTC-124), and gentamicin to induce translational read-through or inhibit nonsense-mediated decay. However, the drugs failed to increase the amount of NFL protein to detectable levels and were toxic to iPSC-derived motor neurons.
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Affiliation(s)
- Markus T. Sainio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Tiina Rasila
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Svetlana M. Molchanova
- Molecular and Integrative Biosciences Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Julius Järvilehto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Rubén Torregrosa-Muñumer
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Sandra Harjuhaahto
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Jana Pennonen
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Nadine Huber
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Sanna-Kaisa Herukka
- Department of Neurology, Kuopio University Hospital, Kuopio, Finland
- Neurology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Annakaisa Haapasalo
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Henrik Zetterberg
- Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, United Kingdom
- UK Dementia Research Institute at UCL, London, United Kingdom
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong, Hong Kong SAR, China
| | - Tomi Taira
- Department of Veterinary Biosciences, Faculty of Veterinary Medicine, Department of Veterinary Biosciences for Electrophysiology, University of Helsinki, Helsinki, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Johanna Palmio
- Neuromuscular Research Center, Tampere University Hospital and Tampere University, Tampere, Finland
| | - Emil Ylikallio
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Clinical Neurosciences, Neurology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Henna Tyynismaa
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Neuroscience Center, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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3
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Kainate receptors in the developing neuronal networks. Neuropharmacology 2021; 195:108585. [PMID: 33910033 DOI: 10.1016/j.neuropharm.2021.108585] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022]
Abstract
Kainate receptors (KARs) are highly expressed in the immature brain and have unique developmentally regulated functions that may be important in linking neuronal activity to morphogenesis during activity-dependent fine-tuning of the synaptic connectivity. Altered expression of KARs in the developing neural network leads to changes in glutamatergic connectivity and network excitability, which may lead to long-lasting changes in behaviorally relevant circuitries in the brain. Here, we summarize the current knowledge on physiological and morphogenic functions described for different types of KARs at immature neural circuitries, focusing on their roles in modulating synaptic transmission and plasticity as well as circuit maturation in the rodent hippocampus and amygdala. Finally, we discuss the emerging evidence suggesting that malfunction of KARs in the immature brain may contribute to the pathophysiology underlying developmentally originating neurological disorders.
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4
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Dumon C, Pisella L, Diabira D, Belaidouni Y, Wayman GA, Gaiarsa JL. Developmental Switch of Leptin Action on Network Driven Activity in the Neonatal Rat Hippocampus. Front Cell Neurosci 2019; 13:254. [PMID: 31213989 PMCID: PMC6558146 DOI: 10.3389/fncel.2019.00254] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 05/21/2019] [Indexed: 12/31/2022] Open
Abstract
The adipose-derived circulating hormone leptin plays a pivotal role in the control of energy balance and body weight. Sound data indicate that this hormone also acts as an important developmental signal impacting a number of brain regions during fetal and postnatal stages. Leptin levels surge during the two first postnatal weeks of life in rodents. This period is characterized by the presence of early network driven activity in the immature hippocampus, the so-called Giant Depolarizing Potentials (GDPs). GDPs are thought to contribute to the wiring of the hippocampal network. We therefore tested the effect of leptin on GDPs. Leptin increased GDPs frequency between the postnatal days (P) 1 and 3 via a calcium/Calmodulin-dependent kinase (CaMK) and extracellular signal-related kinase (ERK) dependent pathways. Between P6 and P7, leptin inhibited the frequency of GDPs through the activation of large conductance Ca2+ activated K+ (BK) channels driven by a phosphoinositol-3 kinase (PI3K) dependent pathway. These results show that leptin exerts a bi-directional and age-dependent control of GDPs and extends the scope of leptin’s action in the developing brain.
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Affiliation(s)
- Camille Dumon
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, UMR 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University, Marseille, France
| | - Lucie Pisella
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, UMR 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University, Marseille, France
| | - Diabe Diabira
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, UMR 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University, Marseille, France
| | - Yasmine Belaidouni
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, UMR 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University, Marseille, France
| | - Gary A Wayman
- Program in Neuroscience, Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA, United States
| | - Jean-Luc Gaiarsa
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, UMR 1249, INMED (Institut de Neurobiologie de la Méditerranée), Aix-Marseille University, Marseille, France
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5
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Comhair J, Devoght J, Morelli G, Harvey RJ, Briz V, Borrie SC, Bagni C, Rigo JM, Schiffmann SN, Gall D, Brône B, Molchanova SM. Alpha2-Containing Glycine Receptors Promote Neonatal Spontaneous Activity of Striatal Medium Spiny Neurons and Support Maturation of Glutamatergic Inputs. Front Mol Neurosci 2018; 11:380. [PMID: 30374290 PMCID: PMC6196267 DOI: 10.3389/fnmol.2018.00380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/24/2018] [Indexed: 12/16/2022] Open
Abstract
Glycine receptors (GlyRs) containing the α2 subunit are highly expressed in the developing brain, where they regulate neuronal migration and maturation, promote spontaneous network activity and subsequent development of synaptic connections. Mutations in GLRA2 are associated with autism spectrum disorder, but the underlying pathophysiology is not described yet. Here, using Glra2-knockout mice, we found a GlyR-dependent effect on neonatal spontaneous activity of dorsal striatum medium spiny neurons (MSNs) and maturation of the incoming glutamatergic innervation. Our data demonstrate that functional GlyRs are highly expressed in MSNs of one-week-old mice, but they do not generate endogenous chloride-mediated tonic or phasic current. Despite of that, knocking out the Glra2 severely affects the shape of action potentials and impairs spontaneous activity and the frequency of miniature AMPA receptor-mediated currents in MSNs. This reduction in spontaneous activity and glutamatergic signaling can attribute to the observed changes in neonatal behavioral phenotypes as seen in ultrasonic vocalizations and righting reflex. In adult Glra2-knockout animals, the glutamatergic synapses in MSNs remain functionally underdeveloped. The number of glutamatergic synapses and release probability at presynaptic site remain unaffected, but the amount of postsynaptic AMPA receptors is decreased. This deficit is a consequence of impaired development of the neuronal circuitry since acute inhibition of GlyRs by strychnine in adult MSNs does not affect the properties of glutamatergic synapses. Altogether, these results demonstrate that GlyR-mediated signaling supports neonatal spontaneous MSN activity and, in consequence, promotes the functional maturation of glutamatergic synapses on MSNs. The described mechanism might shed light on the pathophysiological mechanisms in GLRA2-linked autism spectrum disorder cases.
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Affiliation(s)
- Joris Comhair
- Laboratory of Neurophysiology, ULB-Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium.,BIOMED Research Institute, University of Hasselt, Hasselt, Belgium
| | - Jens Devoght
- BIOMED Research Institute, University of Hasselt, Hasselt, Belgium
| | - Giovanni Morelli
- BIOMED Research Institute, University of Hasselt, Hasselt, Belgium
| | - Robert J Harvey
- School of Health and Sport Sciences, University of the Sunshine Coast, Sippy Downs, QLD, Australia.,Sunshine Coast Health Institute, Birtinya, QLD, Australia
| | - Victor Briz
- Center for Human Genetics and Leuven Research Institute for Neuroscience and Disease, KU Leuven, Leuven, Belgium.,VIB Center for the Biology of Disease, Leuven, Belgium
| | - Sarah C Borrie
- Center for Human Genetics and Leuven Research Institute for Neuroscience and Disease, KU Leuven, Leuven, Belgium.,VIB Center for the Biology of Disease, Leuven, Belgium
| | - Claudia Bagni
- Center for Human Genetics and Leuven Research Institute for Neuroscience and Disease, KU Leuven, Leuven, Belgium.,VIB Center for the Biology of Disease, Leuven, Belgium
| | - Jean-Michel Rigo
- BIOMED Research Institute, University of Hasselt, Hasselt, Belgium
| | - Serge N Schiffmann
- Laboratory of Neurophysiology, ULB-Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - David Gall
- Laboratory of Neurophysiology, ULB-Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
| | - Bert Brône
- BIOMED Research Institute, University of Hasselt, Hasselt, Belgium
| | - Svetlana M Molchanova
- Laboratory of Neurophysiology, ULB-Neuroscience Institute, Université Libre de Bruxelles, Brussels, Belgium
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6
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Atanasova T, Kharybina Z, Kaarela T, Huupponen J, Luchkina NV, Taira T, Lauri SE. GluA4 Dependent Plasticity Mechanisms Contribute to Developmental Synchronization of the CA3-CA1 Circuitry in the Hippocampus. Neurochem Res 2017; 44:562-571. [PMID: 28856535 DOI: 10.1007/s11064-017-2392-8] [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: 05/29/2017] [Revised: 08/14/2017] [Accepted: 08/16/2017] [Indexed: 10/24/2022]
Abstract
During the course of development, molecular mechanisms underlying activity-dependent synaptic plasticity change considerably. At immature CA3-CA1 synapses in the hippocampus, PKA-driven synaptic insertion of GluA4 AMPA receptors is the predominant mechanism for synaptic strengthening. However, the physiological significance of the developmentally restricted GluA4-dependent plasticity mechanisms is poorly understood. Here we have used microelectrode array (MEA) recordings in GluA4 deficient slice cultures to study the role of GluA4 in early development of the hippocampal circuit function. We find that during the first week in culture (DIV2-6) when GluA4 expression is restricted to pyramidal neurons, loss of GluA4 has no effect on the overall excitability of the immature network, but significantly impairs synchronization of the CA3 and CA1 neuronal populations. In the absence of GluA4, the temporal correlation of the population spiking activity between CA3-CA1 neurons was significantly lower as compared to wild-types at DIV6. Our data show that synapse-level defects in transmission and plasticity mechanisms are efficiently compensated for to normalize population firing rate at the immature hippocampal network. However, lack of the plasticity mechanisms typical for the immature synapses may perturb functional coupling between neuronal sub-populations, a defect frequently implicated in the context of developmentally originating neuropsychiatric disorders.
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Affiliation(s)
- Tsvetomira Atanasova
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Zoya Kharybina
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Tiina Kaarela
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Johanna Huupponen
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Natalia V Luchkina
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Psychiatry, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA
| | - Tomi Taira
- Neuroscience Center, University of Helsinki, Helsinki, Finland.,Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sari E Lauri
- Neuroscience Center, University of Helsinki, Helsinki, Finland. .,Department of Biosciences, University of Helsinki, Helsinki, Finland.
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7
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Molchanova SM, Huupponen J, Lauri SE, Taira T. Gap junctions between CA3 pyramidal cells contribute to network synchronization in neonatal hippocampus. Neuropharmacology 2016; 107:9-17. [DOI: 10.1016/j.neuropharm.2016.02.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 01/28/2016] [Accepted: 02/24/2016] [Indexed: 10/22/2022]
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8
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Krawczyk M, Ramani M, Dian J, Florez CM, Mylvaganam S, Brien J, Reynolds J, Kapur B, Zoidl G, Poulter MO, Carlen PL. Hippocampal hyperexcitability in fetal alcohol spectrum disorder: Pathological sharp waves and excitatory/inhibitory synaptic imbalance. Exp Neurol 2016; 280:70-9. [PMID: 26996134 DOI: 10.1016/j.expneurol.2016.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 02/29/2016] [Accepted: 03/13/2016] [Indexed: 01/01/2023]
Abstract
Prenatal alcohol exposure (PAE) can lead to long-lasting neurological alterations that may predispose individuals to seizures and neurobehavioral dysfunction. To date, there exists limited information regarding the underlying pathophysiological mechanisms. The hippocampal CA3 region generates excitatory population activity, called sharp waves (SPWs), that provide an ideal model to study perturbations in neuronal excitability at the network and cellular levels. In the present study, we utilized a mouse model of PAE and used dual extracellular and whole-cell patch-clamp recordings from CA3 hippocampal pyramidal cells to evaluate the effect of 1st trimester-equivalent ethanol exposure (10% v/v) on SPW activity and excitatory/inhibitory balance. We observed that PAE significantly altered in vitro SPW waveforms, with an increased duration and amplitude, when compared to controls. In addition, PAE slices exhibited reduced pharmacological inhibition by the GABA-A receptor antagonist bicuculline (BMI) on SPW activity, and increased population spike paired-pulse ratios, all indicative of network disinhibition within the PAE hippocampus. Evaluation of PAE CA3 pyramidal cell activity associated with SPWs, revealed increased action potential cell firing, which was accompanied by an imbalance of excitatory/inhibitory synaptic drive, shifted in favor of excitation. Moreover, we observed intrinsic changes in CA3 pyramidal activity in PAE animals, including increased burst firing and instantaneous firing rate. This is the first study to provide evidence for hippocampal dysfunction in the ability to maintain network homeostasis and underlying cellular hyperexcitability in a model of PAE. These circuit and cellular level alterations may contribute to the increased propensity for seizures and neurobehavioral dysfunction observed in patients with a history of PAE.
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Affiliation(s)
- Michal Krawczyk
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada.
| | - Meera Ramani
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Josh Dian
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Carlos M Florez
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Shanthini Mylvaganam
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - James Brien
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - James Reynolds
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Bhushan Kapur
- Division of Clinical Pharmacology & Toxicology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Georg Zoidl
- Department of Biology, York University, Toronto, ON, Canada; Department of Psychology, York University, Toronto, ON, Canada
| | - Michael O Poulter
- Robarts Research Institute and Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Peter L Carlen
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada
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9
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Huupponen J, Atanasova T, Taira T, Lauri SE. GluA4 subunit of AMPA receptors mediates the early synaptic response to altered network activity in the developing hippocampus. J Neurophysiol 2016; 115:2989-96. [PMID: 26961102 DOI: 10.1152/jn.00435.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 03/03/2016] [Indexed: 11/22/2022] Open
Abstract
Development of the neuronal circuitry involves both Hebbian and homeostatic plasticity mechanisms that orchestrate activity-dependent refinement of the synaptic connectivity. AMPA receptor subunit GluA4 is expressed in hippocampal pyramidal neurons during early postnatal period and is critical for neonatal long-term potentiation; however, its role in homeostatic plasticity is unknown. Here we show that GluA4-dependent plasticity mechanisms allow immature synapses to promptly respond to alterations in network activity. In the neonatal CA3, the threshold for homeostatic plasticity is low, and a 15-h activity blockage with tetrodotoxin triggers homeostatic upregulation of glutamatergic transmission. On the other hand, attenuation of the correlated high-frequency bursting in the CA3-CA1 circuitry leads to weakening of AMPA transmission in CA1, thus reflecting a critical role for Hebbian synapse induction in the developing CA3-CA1. Both of these developmentally restricted forms of plasticity were absent in GluA4(-/-) mice. These data suggest that GluA4 enables efficient homeostatic upscaling and responsiveness to temporal activity patterns during the critical period of activity-dependent refinement of the circuitry.
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Affiliation(s)
- J Huupponen
- Neuroscience Center, University of Helsinki, Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland; and
| | - T Atanasova
- Neuroscience Center, University of Helsinki, Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland; and
| | - T Taira
- Neuroscience Center, University of Helsinki, Helsinki, Finland; Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - S E Lauri
- Neuroscience Center, University of Helsinki, Helsinki, Finland; Department of Biosciences, University of Helsinki, Helsinki, Finland; and
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10
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Observation of Distressed Conspecific as a Model of Emotional Trauma Generates Silent Synapses in the Prefrontal-Amygdala Pathway and Enhances Fear Learning, but Ketamine Abolishes those Effects. Neuropsychopharmacology 2015; 40:2536-45. [PMID: 25865929 PMCID: PMC4569943 DOI: 10.1038/npp.2015.100] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2014] [Revised: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 12/21/2022]
Abstract
Witnessing pain and distress in others can cause psychological trauma and increase odds of developing PTSD in the future, on exposure to another stressful event. However, the underlying synaptic process remains unknown. Here we report that mice exposed to a conspecific receiving electrical footshocks exhibited enhanced passive avoidance (PA) learning when trained 24 h after the exposure. The exposure activated neurons in the dorsomedial prefrontal cortex (dmPFC) and basolateral amygdala (BLA) and altered synaptic transmission from dmPFC to BLA. It increased amplitude, slowed decay of NMDA receptor-mediated currents, and generated silent synapses. Administration of sub-anesthetic ketamine immediately after the exposure prevented the enhancement of PA learning and silent synapse formation. These findings suggest that ketamine can prevent pathophysiological consequences of psychological trauma.
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11
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Johnson-Venkatesh EM, Khan MN, Murphy GG, Sutton MA, Umemori H. Excitability governs neural development in a hippocampal region-specific manner. Development 2015; 142:3879-91. [PMID: 26417041 DOI: 10.1242/dev.121202] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Accepted: 09/10/2015] [Indexed: 01/23/2023]
Abstract
Neuronal activity, including intrinsic neuronal excitability and synaptic transmission, is an essential regulator of brain development. However, how the intrinsic neuronal excitability of distinct neurons affects their integration into developing circuits remains poorly understood. To investigate this problem, we created several transgenic mouse lines in which intrinsic excitability is suppressed, and the neurons are effectively silenced, in different excitatory neuronal populations of the hippocampus. Here we show that CA1, CA3 and dentate gyrus neurons each have unique responses to suppressed intrinsic excitability during circuit development. Silenced CA1 pyramidal neurons show altered spine development and synaptic transmission after postnatal day 15. By contrast, silenced CA3 pyramidal neurons seem to develop normally. Silenced dentate granule cells develop with input-specific decreases in spine density starting at postnatal day 11; however, a compensatory enhancement of neurotransmitter release onto these neurons maintains normal levels of synaptic activity. The synaptic changes in CA1 and dentate granule neurons are not observed when synaptic transmission, rather than intrinsic excitability, is blocked in these neurons. Thus, our results demonstrate a crucial role for intrinsic neuronal excitability in establishing hippocampal connectivity and reveal that neuronal development in each hippocampal region is distinctly regulated by excitability.
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Affiliation(s)
- Erin M Johnson-Venkatesh
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Mudassar N Khan
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Geoffrey G Murphy
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Michael A Sutton
- Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Hisashi Umemori
- Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA Molecular & Behavioral Neuroscience Institute, University of Michigan Medical School, Ann Arbor, MI 48109, USA Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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Developmental switch in the kinase dependency of long-term potentiation depends on expression of GluA4 subunit-containing AMPA receptors. Proc Natl Acad Sci U S A 2014; 111:4321-6. [PMID: 24599589 DOI: 10.1073/pnas.1315769111] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The AMPA-receptor subunit GluA4 is expressed transiently in CA1 pyramidal neurons at the time synaptic connectivity is forming, but its physiological significance is unknown. Here we show that GluA4 expression is sufficient to alter the signaling requirements of long-term potentiation (LTP) and can fully explain the switch in the LTP kinase dependency from PKA to Ca2(+)/calmodulin-dependent protein kinase II during synapse maturation. At immature synapses, activation of PKA leads to a robust potentiation of AMPA-receptor function via the mobilization of GluA4. Analysis of GluA4-deficient mice indicates that this mechanism is critical for neonatal PKA-dependent LTP. Furthermore, lentiviral expression of GluA4 in CA1 neurons conferred a PKA-dependent synaptic potentiation and LTP regardless of the developmental stage. Thus, GluA4 defines the signaling requirements for LTP and silent synapse activation during a critical period of synapse development.
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Hanse E, Seth H, Riebe I. AMPA-silent synapses in brain development and pathology. Nat Rev Neurosci 2013; 14:839-50. [DOI: 10.1038/nrn3642] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Of bandwagons and bathwater: the value of resting state functional magnetic resonance imaging for child psychiatric research. J Am Acad Child Adolesc Psychiatry 2013; 52:562-5. [PMID: 23702443 DOI: 10.1016/j.jaac.2013.03.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 02/27/2013] [Accepted: 03/04/2013] [Indexed: 12/15/2022]
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