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Fukuchi M. Studies of Neuronal Gene Regulation Controlling the Molecular Mechanisms Underlying Neural Plasticity. YAKUGAKU ZASSHI 2017; 137:1103-1115. [PMID: 28867697 DOI: 10.1248/yakushi.17-00107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The regulation of the development and function of the nervous system is not preprogramed but responds to environmental stimuli to change neural development and function flexibly. This neural plasticity is a characteristic property of the nervous system. For example, strong synaptic activation evoked by environmental stimuli leads to changes in synaptic functions (known as synaptic plasticity). Long-lasting synaptic plasticity is one of the molecular mechanisms underlying long-term learning and memory. Since discovering the role of the transcription factor cAMP-response element-binding protein in learning and memory, it has been widely accepted that gene regulation in neurons contributes to long-lasting changes in neural functions. However, it remains unclear how synaptic activation is converted into gene regulation that results in long-lasting neural functions like long-term memory. We continue to address this question. This review introduces our recent findings on the gene regulation of brain-derived neurotrophic factor and discusses how regulation of the gene participates in long-lasting changes in neural functions.
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Affiliation(s)
- Mamoru Fukuchi
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama
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102
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Fukuchi M, Sanabe T, Watanabe T, Kubota T, Tabuchi A, Tsuda M. Distinct regulation of activity-dependent transcription of immediate early genes in cultured rat cortical neurons. Biochem Biophys Res Commun 2017. [PMID: 28634074 DOI: 10.1016/j.bbrc.2017.06.101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The activity-regulated expression of immediate early genes (IEGs) contributes to long-lasting neuronal functions underlying long-term memory. However, their response properties following neuronal activity are unique and remain poorly understood. To address this knowledge gap, here we further investigated the response properties of two representative IEGs, c-fos and brain-derived neurotrophic factor (Bdnf). Treatment of cultured cortical cells with KCl produces a depolarization process that results in the increase of intracellular calcium concentration in a KCl concentration-dependent manner. Consistent with this increase, c-fos expression was induced in a KCl concentration-dependent manner. In contrast, however, Bdnf expression was optimally activated by both 25 and 50 mM concentration of KCl. Similar results were observed when the cells were treated with okadaic acid, which inhibits protein phosphatases and elicits the hyper-phosphorylation of signaling molecules. Thus, Bdnf expression is strictly regulated by a neuronal activity threshold in an all or nothing manner, whereas c-fos expression is activated in a neuronal activity-dependent manner. Our findings also suggest that these differential responses might be due to the presence or absence of a TATA box.
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Affiliation(s)
- Mamoru Fukuchi
- Laboratory of Molecular Neuroscience, Faculty of Pharmacy, Takasaki University of Health and Welfare, 60 Nakaorui-machi, Takasaki-shi, Gunma 370-0033, Japan; Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan.
| | - Tomofumi Sanabe
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan
| | - Toshifumi Watanabe
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan
| | - Takane Kubota
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan
| | - Akiko Tabuchi
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan
| | - Masaaki Tsuda
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama-shi, Toyama 930-0194, Japan
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103
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Mauger O, Lemoine F, Scheiffele P. Targeted Intron Retention and Excision for Rapid Gene Regulation in Response to Neuronal Activity. Neuron 2017; 92:1266-1278. [PMID: 28009274 DOI: 10.1016/j.neuron.2016.11.032] [Citation(s) in RCA: 140] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 10/14/2016] [Accepted: 11/18/2016] [Indexed: 01/03/2023]
Abstract
Activity-dependent transcription has emerged as a major source of gene products that regulate neuronal excitability, connectivity, and synaptic properties. However, the elongation rate of RNA polymerases imposes a significant temporal constraint for transcript synthesis, in particular for long genes where new synthesis requires hours. Here we reveal a novel, transcription-independent mechanism that releases transcripts within minutes of neuronal stimulation. We found that, in the mouse neocortex, polyadenylated transcripts retain select introns and are stably accumulated in the cell nucleus. A subset of these intron retention transcripts undergoes activity-dependent splicing, cytoplasmic export, and ribosome loading, thus acutely releasing mRNAs in response to stimulation. This process requires NMDA receptor- and calmodulin-dependent kinase pathways, and it is particularly prevalent for long transcripts. We conclude that regulated intron retention in fully transcribed RNAs represents a mechanism to rapidly mobilize a pool of mRNAs in response to neuronal activity.
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Affiliation(s)
- Oriane Mauger
- Biozentrum of the University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland
| | - Frédéric Lemoine
- GenoSplice Technology, iPEPS-ICM, Hôpital de la Pitié Salpêtrière, 75013 Paris, France
| | - Peter Scheiffele
- Biozentrum of the University of Basel, Klingelbergstrasse 50-70, 4056 Basel, Switzerland.
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104
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Sun MY, Chisari M, Eisenman LN, Zorumski CF, Mennerick SJ. Contributions of space-clamp errors to apparent time-dependent loss of Mg 2+ block induced by NMDA. J Neurophysiol 2017; 118:532-543. [PMID: 28356471 DOI: 10.1152/jn.00106.2017] [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: 02/15/2017] [Revised: 03/17/2017] [Accepted: 03/27/2017] [Indexed: 11/22/2022] Open
Abstract
N-methyl-d-aspartate receptors (NMDARs) govern synaptic plasticity, development, and neuronal response to insult. Prolonged activation of NMDARs such as during an insult may activate secondary currents or modulate Mg2+ sensitivity, but the conditions under which these occur are not fully defined. We reexamined the effect of prolonged NMDAR activation in juvenile mouse hippocampal slices. NMDA (10 μM) elicited current with the expected negative-slope conductance in the presence of 1.2 mM Mg2+ However, several minutes of continued NMDA exposure elicited additional inward current at -70 mV. A higher concentration of NMDA (100 µM) elicited the current more rapidly. The additional current was not dependent on Ca2+, network activity, or metabotropic NMDAR function and did not persist on agonist removal. Voltage ramps revealed no alteration of either reversal potential or NMDA-elicited conductance between -30 mV and +50 mV. The result was a more linear NMDA current-voltage relationship. The current linearization was also induced in interneurons and in mature dentate granule neurons but not immature dentate granule cells, dissociated cultured hippocampal neurons, or nucleated patches excised from CA1 pyramidal neurons. Comparative simulations of NMDA application to a CA1 pyramidal neuron and to a cultured neuron revealed that linearization can be explained by space-clamp errors arising from gradual recruitment of distal dendritic NMDARs. We conclude that persistent secondary currents do not strongly contribute to NMDAR responses in juvenile mouse hippocampus and careful discernment is needed to exclude contributions of clamp artifacts to apparent secondary currents.NEW & NOTEWORTHY We report that upon sustained activation of NMDARs in juvenile mouse hippocampal neurons there is apparent loss of Mg2+ block at negative membrane potentials. However, the phenomenon is explained by loss of dendritic voltage clamp, leading to a linear current-voltage relationship. Our results give a specific example of how spatial voltage errors in voltage-clamp recordings can readily be misinterpreted as biological modulation.
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Affiliation(s)
- Min-Yu Sun
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Mariangela Chisari
- Department of Biomedical and Biotechnological Sciences, Section of Pharmacology, University of Catania, Catania, Italy
| | - Lawrence N Eisenman
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri.,Center for Brain Research in Mood Disorders, Washington University School of Medicine, St. Louis, Missouri; and
| | - Steven J Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; .,Department of Neuroscience, Washington University School of Medicine, St. Louis, Missouri.,Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
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105
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Warren BL, Suto N, Hope BT. Mechanistic Resolution Required to Mediate Operant Learned Behaviors: Insights from Neuronal Ensemble-Specific Inactivation. Front Neural Circuits 2017; 11:28. [PMID: 28484375 PMCID: PMC5401897 DOI: 10.3389/fncir.2017.00028] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 04/05/2017] [Indexed: 12/21/2022] Open
Abstract
Many learned behaviors are directed by complex sets of highly specific stimuli or cues. The neural mechanisms mediating learned associations in these behaviors must be capable of storing complex cue information and distinguishing among different learned associations—we call this general concept “mechanistic resolution”. For many years, our understanding of the circuitry of these learned behaviors has been based primarily on inactivation of specific cell types or whole brain areas regardless of which neurons were activated during the cue-specific behaviors. However, activation of all cells or specific cell types in a brain area do not have enough mechanistic resolution to encode or distinguish high-resolution learned associations in these behaviors. Instead, these learned associations are likely encoded within specific patterns of sparsely distributed neurons called neuronal ensembles that are selectively activated by the cues. This review article focuses on studies of neuronal ensembles in operant learned responding to obtain food or drug rewards. These studies suggest that the circuitry of operant learned behaviors may need to be re-examined using ensemble-specific manipulations that have the requisite level of mechanistic resolution.
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Affiliation(s)
- Brandon L Warren
- Behavioral Neuroscience Branch, Intramural Research Program (IRP), National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Department of Health and Human Services (DHHS)Baltimore, MD, USA
| | - Nobuyoshi Suto
- Department of Molecular and Cellular Neuroscience, The Scripps Research InstituteLa Jolla, CA, USA
| | - Bruce T Hope
- Behavioral Neuroscience Branch, Intramural Research Program (IRP), National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Department of Health and Human Services (DHHS)Baltimore, MD, USA
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106
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Lanshakov DA, Drozd US, Dygalo NN. Optogenetic Stimulation Increases Level of Antiapoptotic Protein Bcl-xL in Neurons. BIOCHEMISTRY (MOSCOW) 2017; 82:340-344. [PMID: 28320275 DOI: 10.1134/s0006297917030129] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The antiapoptotic protein Bcl-xL is associated with several neuroplastic processes such as formation of synapses, regulation of spontaneous and evoked synaptic responses, and release of neurotransmitters. Dependence of expression on activity of neurons is characteristic for many proteins participating in regulation of neuroplasticity. Whether such property is exhibited by the Bcl-xL protein was analyzed using in vivo optogenetic stimulation of hippocampal glutamatergic neurons expressing channelrhodopsin ChR2H134 under CAMKIIa promoter in the adeno-associated viral vector, followed by immunohistochemical determination of the level of Bcl-xL protein in these neurons and surrounding cells. Increase in the level of early response c-Fos protein following illumination with blue light was indicative of activation of these hippocampal neurons. The optogenetic activation of hippocampus resulted in a significant increase in the level of antiapoptotic protein Bcl-xL in the photosensitive neurons as well as in the surrounding cells. The dependence of the level of expression of Bcl-xL protein on the activity of neurons indicates that this protein possesses one more important property that is essential for participation in neuroplastic processes in the brain.
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Affiliation(s)
- D A Lanshakov
- Institute of Cytology and Genetics, Siberian Division of the Russian Academy of Sciences, Novosibirsk, 630090, Russia
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107
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Activity-Induced Synaptic Structural Modifications by an Activator of Integrin Signaling at the Drosophila Neuromuscular Junction. J Neurosci 2017; 37:3246-3263. [PMID: 28219985 DOI: 10.1523/jneurosci.3128-16.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 02/08/2017] [Accepted: 02/14/2017] [Indexed: 11/21/2022] Open
Abstract
Activity-induced synaptic structural modification is crucial for neural development and synaptic plasticity, but the molecular players involved in this process are not well defined. Here, we report that a protein named Shriveled (Shv) regulates synaptic growth and activity-dependent synaptic remodeling at the Drosophila neuromuscular junction. Depletion of Shv causes synaptic overgrowth and an accumulation of immature boutons. We find that Shv physically and genetically interacts with βPS integrin. Furthermore, Shv is secreted during intense, but not mild, neuronal activity to acutely activate integrin signaling, induce synaptic bouton enlargement, and increase postsynaptic glutamate receptor abundance. Consequently, loss of Shv prevents activity-induced synapse maturation and abolishes post-tetanic potentiation, a form of synaptic plasticity. Our data identify Shv as a novel trans-synaptic signal secreted upon intense neuronal activity to promote synapse remodeling through integrin receptor signaling.SIGNIFICANCE STATEMENT The ability of neurons to rapidly modify synaptic structure in response to neuronal activity, a process called activity-induced structural remodeling, is crucial for neuronal development and complex brain functions. The molecular players that are important for this fundamental biological process are not well understood. Here we show that the Shriveled (Shv) protein is required during development to maintain normal synaptic growth. We further demonstrate that Shv is selectively released during intense neuronal activity, but not mild neuronal activity, to acutely activate integrin signaling and trigger structural modifications at the Drosophila neuromuscular junction. This work identifies Shv as a key modulator of activity-induced structural remodeling and suggests that neurons use distinct molecular cues to differentially modulate synaptic growth and remodeling to meet synaptic demand.
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108
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Abstract
The classic serotonergic hallucinogens, or psychedelics, have the ability to profoundly alter perception and behavior. These can include visual distortions, hallucinations, detachment from reality, and mystical experiences. Some psychedelics, like LSD, are able to produce these effects with remarkably low doses of drug. Others, like psilocybin, have recently been demonstrated to have significant clinical efficacy in the treatment of depression, anxiety, and addiction that persist for at least several months after only a single therapeutic session. How does this occur? Much work has recently been published from imaging studies showing that psychedelics alter brain network connectivity. They facilitate a disintegration of the default mode network, producing a hyperconnectivity between brain regions that allow centers that do not normally communicate with each other to do so. The immediate and acute effects on both behaviors and network connectivity are likely mediated by effector pathways downstream of serotonin 5-HT2A receptor activation. These acute molecular processes also influence gene expression changes, which likely influence synaptic plasticity and facilitate more long-term changes in brain neurochemistry ultimately underlying the therapeutic efficacy of a single administration to achieve long-lasting effects. In this review, we summarize what is currently known about the molecular genetic responses to psychedelics within the brain and discuss how gene expression changes may contribute to altered cellular physiology and behaviors.
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109
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Eyileten C, Kaplon-Cieslicka A, Mirowska-Guzel D, Malek L, Postula M. Antidiabetic Effect of Brain-Derived Neurotrophic Factor and Its Association with Inflammation in Type 2 Diabetes Mellitus. J Diabetes Res 2017; 2017:2823671. [PMID: 29062839 PMCID: PMC5618763 DOI: 10.1155/2017/2823671] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/12/2017] [Accepted: 08/22/2017] [Indexed: 01/07/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is a neurotrophin, which plays an important role in the central nervous system, and systemic or peripheral inflammatory conditions, such as acute coronary syndrome and type 2 diabetes mellitus (T2DM). BDNF is also expressed in several nonneuronal tissues, and platelets are the major source of peripheral BDNF. Here, we reviewed the potential role of BDNF in platelet reactivity in T2DM and its association with selected inflammatory and platelet activation mediators. Besides that, we focused on adipocytokines such as leptin, resistin, and adiponectin which are considered to take part in inflammation and both lipid and glucose metabolism in diabetic patients as previous studies showed the relation between adipocytokines and BDNF. We also reviewed the evidences of the antidiabetic effect of BDNF and the association with circulating inflammatory cytokines in T2DM.
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Affiliation(s)
- Ceren Eyileten
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Center for Preclinical Research and Technology CEPT, Warsaw, Poland
| | | | - Dagmara Mirowska-Guzel
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Center for Preclinical Research and Technology CEPT, Warsaw, Poland
| | - Lukasz Malek
- Faculty of Rehabilitation, University of Physical Education, Warsaw, Poland
| | - Marek Postula
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Center for Preclinical Research and Technology CEPT, Warsaw, Poland
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110
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Mehan S, Parveen S, Kalra S. Adenyl cyclase activator forskolin protects against Huntington's disease-like neurodegenerative disorders. Neural Regen Res 2017; 12:290-300. [PMID: 28400813 PMCID: PMC5361515 DOI: 10.4103/1673-5374.200812] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Long term suppression of succinate dehydrogenase by selective inhibitor 3-nitropropionic acid has been used in rodents to model Huntington's disease where mitochondrial dysfunction and oxidative damages are primary pathological hallmarks for neuronal damage. Improvements in learning and memory abilities, recovery of energy levels, and reduction of excitotoxicity damage can be achieved through activation of Adenyl cyclase enzyme by a specific phytochemical forskolin. In this study, intraperitoneal administration of 10 mg/kg 3-nitropropionic acid for 15 days in rats notably reduced body weight, worsened motor cocordination (grip strength, beam crossing task, locomotor activity), resulted in learning and memory deficits, greatly increased acetylcholinesterase, lactate dehydrogenase, nitrite, and malondialdehyde levels, obviously decreased adenosine triphosphate, succinate dehydrogenase, superoxide dismutase, catalase, and reduced glutathione levels in the striatum, cortex and hippocampus. Intragastric administration of forskolin at 10, 20, 30 mg/kg dose-dependently reversed these behavioral, biochemical and pathological changes caused by 3-nitropropionic acid. These results suggest that forskolin exhibits neuroprotective effects on 3-nitropropionic acid-induced Huntington's disease-like neurodegeneration.
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Affiliation(s)
- Sidharth Mehan
- Department of Pharamcology, Rajendra Institute of Technology & Sciences, Sirsa, Haryana, India
| | - Shaba Parveen
- Department of Pharamcology, Rajendra Institute of Technology & Sciences, Sirsa, Haryana, India
| | - Sanjeev Kalra
- Department of Pharamcology, Rajendra Institute of Technology & Sciences, Sirsa, Haryana, India
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111
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Harricharan R, Abboussi O, Daniels WM. Addiction: A dysregulation of satiety and inflammatory processes. PROGRESS IN BRAIN RESEARCH 2017; 235:65-91. [DOI: 10.1016/bs.pbr.2017.07.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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112
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Swanger SA, Chen W, Wells G, Burger PB, Tankovic A, Bhattacharya S, Strong KL, Hu C, Kusumoto H, Zhang J, Adams DR, Millichap JJ, Petrovski S, Traynelis SF, Yuan H. Mechanistic Insight into NMDA Receptor Dysregulation by Rare Variants in the GluN2A and GluN2B Agonist Binding Domains. Am J Hum Genet 2016; 99:1261-1280. [PMID: 27839871 PMCID: PMC5142120 DOI: 10.1016/j.ajhg.2016.10.002] [Citation(s) in RCA: 132] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 10/03/2016] [Indexed: 12/30/2022] Open
Abstract
Epilepsy and intellectual disability are associated with rare variants in the GluN2A and GluN2B (encoded by GRIN2A and GRIN2B) subunits of the N-methyl-D-aspartate receptor (NMDAR), a ligand-gated ion channel with essential roles in brain development and function. By assessing genetic variation across GluN2 domains, we determined that the agonist binding domain, transmembrane domain, and the linker regions between these domains were particularly intolerant to functional variation. Notably, the agonist binding domain of GluN2B exhibited significantly more variation intolerance than that of GluN2A. To understand the ramifications of missense variation in the agonist binding domain, we investigated the mechanisms by which 25 rare variants in the GluN2A and GluN2B agonist binding domains dysregulated NMDAR activity. When introduced into recombinant human NMDARs, these rare variants identified in individuals with neurologic disease had complex, and sometimes opposing, consequences on agonist binding, channel gating, receptor biogenesis, and forward trafficking. Our approach combined quantitative assessments of these effects to estimate the overall impact on synaptic and non-synaptic NMDAR function. Interestingly, similar neurologic diseases were associated with both gain- and loss-of-function variants in the same gene. Most rare variants in GluN2A were associated with epilepsy, whereas GluN2B variants were associated with intellectual disability with or without seizures. Finally, discerning the mechanisms underlying NMDAR dysregulation by these rare variants allowed investigations of pharmacologic strategies to correct NMDAR function.
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Affiliation(s)
- Sharon A Swanger
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Wenjuan Chen
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gordon Wells
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Pieter B Burger
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Anel Tankovic
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Katie L Strong
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Chemistry, Emory University, Atlanta, GA 30322, USA
| | - Chun Hu
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Hirofumi Kusumoto
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Jing Zhang
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - David R Adams
- Undiagnosed Diseases Network, National Human Genome Research Institute, NIH, Bethesda, MD 20892, USA
| | - John J Millichap
- Departments of Pediatrics and Neurology, Northwestern University Feinberg School of Medicine and Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL 60611, USA
| | - Slavé Petrovski
- Department of Medicine, The University of Melbourne, Austin Health and Royal Melbourne Hospital, Melbourne, VIC 3050, Australia
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Hongjie Yuan
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Atlanta, GA 30322, USA.
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113
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Koyama Y, Andoh T, Kamiya Y, Miyazaki T, Maruyama K, Kariya T, Goto T. Bumetanide, an Inhibitor of NKCC1 (Na-K-2Cl Cotransporter Isoform 1), Enhances Propofol-Induced Loss of Righting Reflex but Not Its Immobilizing Actions in Neonatal Rats. PLoS One 2016; 11:e0164125. [PMID: 27783647 PMCID: PMC5081196 DOI: 10.1371/journal.pone.0164125] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 09/20/2016] [Indexed: 01/15/2023] Open
Abstract
Gamma-aminobutyric acid (GABA) has been shown to induce excitation on immature neurons due to increased expression of Na+-K+-2Cl- co-transporter isoform 1 (NKCC1), and the transition of GABAergic signaling from excitatory to inhibitory occurs before birth in the rat spinal cord and spreads rostrally according to the developmental changes in cation-chloride co-transporter expression. We previously showed that midazolam activates the hippocampal CA3 area and induces less sedation in neonatal rats compared with adolescent rats in an NKCC1-dependent manner. In the present study, we tested the hypothesis that propofol-induced loss of righting reflex (LORR) but not immobilizing actions are modulated by NKCC1-dependent mechanisms and reduced in neonatal rats compared with adolescent rats. We estimated neuronal activity in the cortex, hippocampus and thalamus after propofol administration with or without bumetanide, an NKCC1 inhibitor, by immunostaining of phosphorylated cyclic adenosine monophosphate-response element binding protein (pCREB). We studied effects of bumetanide on propofol-induced LORR and immobilizing actions in postnatal day 7 and 28 (P7 and P28) rats. The pCREB expression in the cortex (P = 0.001) and hippocampus (P = 0.01) was significantly greater in the rats receiving propofol only than in the rats receiving propofol plus bumetanide at P 7. Propofol-induced LORR or immobilizing effects did not differ significantly between P7 and P28. Bumetanide significantly enhanced propofol-induced LORR (P = 0.031) but not immobilization in P7 rats. These results are partially consistent with our hypothesis. They suggest that propofol may activate the rostral but not caudal central nervous system dependently on NKCC1, and these differential actions may underlie the different properties of sedative and immobilizing actions observed in neonatal rats.
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Affiliation(s)
- Yukihide Koyama
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
- * E-mail:
| | - Tomio Andoh
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
| | - Yoshinori Kamiya
- Department of Anesthesiology, Niigata University Graduate School of Medicine, Niigata, Japan
| | - Tomoyuki Miyazaki
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Koichi Maruyama
- Department of Anesthesiology, Mizonokuchi Hospital, Teikyo University School of Medicine, Kawasaki, Japan
| | - Takayuki Kariya
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Takahisa Goto
- Department of Anesthesiology and Critical Care Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Japan
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114
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Yeh E, Weiss LA. If genetic variation could talk: What genomic data may teach us about the importance of gene expression regulation in the genetics of autism. Mol Cell Probes 2016; 30:346-356. [PMID: 27751841 DOI: 10.1016/j.mcp.2016.10.007] [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: 07/07/2016] [Revised: 10/09/2016] [Accepted: 10/13/2016] [Indexed: 11/25/2022]
Abstract
Autism spectrum disorder (ASD) has been long known to have substantial genetic etiology. Much research has attempted to identify specific genes contributing to ASD risk with the goal of tying gene function to a molecular pathological explanation for ASD. A unifying molecular pathology would potentially increase understanding of what is going wrong during development, and could lead to diagnostic biomarkers or targeted preventative or therapeutic directions. We review past and current genetic mapping approaches and discuss major results, leading to the hypothesis that global dysregulation of gene or protein expression may be implicated in ASD rather than disturbance of brain-specific functions. If substantiated, this hypothesis might indicate the need for novel experimental and analytical approaches in order to understand this neurodevelopmental disorder, develop biomarkers, or consider treatment approaches.
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Affiliation(s)
- Erika Yeh
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - Lauren A Weiss
- Department of Psychiatry, University of California, San Francisco, San Francisco, CA, 94143, USA; Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94143, USA.
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115
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Unravelling cortico-hypothalamic pathways regulating unconditioned fear-induced antinociception and defensive behaviours. Neuropharmacology 2016; 113:367-385. [PMID: 27717879 DOI: 10.1016/j.neuropharm.2016.10.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 09/26/2016] [Accepted: 10/01/2016] [Indexed: 12/30/2022]
Abstract
The medial prefrontal cortex can influence unconditioned fear-induced defensive mechanisms organised by diencephalic neurons that are under tonic GABAergic inhibition. The posterior hypothalamus (PH) is involved with anxiety- and panic attack-like responses. To understand this cortical mediation, our study characterised anterior cingulate cortex (ACC)-PH pathways and investigated the effect of ACC local inactivation with lidocaine. We also investigated the involvement of PH ionotropic glutamate receptors in the defensive behaviours and fear-induced antinociception by microinjecting NBQX (an AMPA/kainate receptor antagonist) and LY235959 (a NMDA receptor antagonist) into the PH. ACC pretreatment with lidocaine decreased the proaversive effect and antinociception evoked by GABAA receptor blockade in the PH, which suggests that there may be descending excitatory pathways from this cortical region to the PH. Microinjections of both NBQX and LY235959 into the PH also attenuated defensive and antinociceptive responses. This suggests that the blockade of AMPA/kainate and NMDA receptors reduces the activity of glutamatergic efferent pathways. Both inputs from the ACC to the PH and glutamatergic hypothalamic short links disinhibited by intra-hypothalamic GABAA receptors blockade are potentially implicated. Microinjection of a bidirectional neurotracer in the PH showed a Cg1-PH pathway and PH neuronal reciprocal connections with the periaqueductal grey matter. Microinjections of an antegrade neurotracer into the Cg1 showed axonal fibres and glutamatergic vesicle-immunoreactive terminal boutons surrounding both mediorostral-lateroposterior thalamic nucleus and PH neuronal perikarya. These data suggest a critical role played by ACC-PH glutamatergic pathways and AMPA/kainate and NMDA receptors in the panic attack-like reactions and antinociception organised by PH neurons.
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116
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Hu C, Chen W, Myers SJ, Yuan H, Traynelis SF. Human GRIN2B variants in neurodevelopmental disorders. J Pharmacol Sci 2016; 132:115-121. [PMID: 27818011 PMCID: PMC5125235 DOI: 10.1016/j.jphs.2016.10.002] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 09/29/2016] [Accepted: 09/29/2016] [Indexed: 11/25/2022] Open
Abstract
The development of whole exome/genome sequencing technologies has given rise to an unprecedented volume of data linking patient genomic variability to brain disorder phenotypes. A surprising number of variants have been found in the N-methyl-d-aspartate receptor (NMDAR) gene family, with the GRIN2B gene encoding the GluN2B subunit being implicated in many cases of neurodevelopmental disorders, which are psychiatric conditions originating in childhood and include language, motor, and learning disorders, autism spectrum disorder (ASD), attention deficit hyperactivity disorder (ADHD), developmental delay, epilepsy, and schizophrenia. The GRIN2B gene plays a crucial role in normal neuronal development and is important for learning and memory. Mutations in human GRIN2B were distributed throughout the entire gene in a number of patients with various neuropsychiatric and developmental disorders. Studies that provide functional analysis of variants are still lacking, however current analysis of de novo variants that segregate with disease cases such as intellectual disability, developmental delay, ASD or epileptic encephalopathies reveal altered NMDAR function. Here, we summarize the current reports of disease-associated variants in GRIN2B from patients with multiple neurodevelopmental disorders, and discuss implications, highlighting the importance of functional analysis and precision medicine therapies.
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Affiliation(s)
- Chun Hu
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Wenjuan Chen
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Scott J Myers
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Hongjie Yuan
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA
| | - Stephen F Traynelis
- Department of Pharmacology, Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA; Center for Functional Evaluation of Rare Variants (CFERV), Emory University School of Medicine, Rollins Research Center, 1510 Clifton Road, Atlanta, GA 30322, USA.
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117
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Radzicki D, Liu E, Deng HX, Siddique T, Martina M. Early Impairment of Synaptic and Intrinsic Excitability in Mice Expressing ALS/Dementia-Linked Mutant UBQLN2. Front Cell Neurosci 2016; 10:216. [PMID: 27703430 PMCID: PMC5028382 DOI: 10.3389/fncel.2016.00216] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/30/2016] [Indexed: 12/11/2022] Open
Abstract
Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are believed to represent the different outcomes of a common pathogenic mechanism. However, while researchers have intensely studied the involvement of motor neurons in the ALS/FTD syndrome, very little is known about the function of hippocampal neurons, although this area is critical for memory and other cognitive functions. We investigated the electrophysiological properties of CA1 pyramidal cells in slices from 1 month-old UBQLN2P497H mice, a recently generated model of ALS/FTD that shows heavy depositions of ubiquilin2-positive aggregates in this brain region. We found that, compared to wild-type mice, cells from UBQLN2P497H mice were hypo-excitable. The amplitude of the glutamatergic currents elicited by afferent fiber stimulation was reduced by ~50%, but no change was detected in paired-pulse plasticity. The maximum firing frequency in response to depolarizing current injection was reduced by ~30%; the fast afterhyperpolarization in response to a range of depolarizations was reduced by almost 10 mV; the maximum slow afterhyperpolarization (sAHP) was also significantly decreased, likely in consequence of the decreased number of spikes. Finally, the action potential (AP) upstroke was blunted and the threshold depolarized compared to controls. Thus, synaptic and intrinsic excitability are both impaired in CA1 pyramidal cells of UBQLN2P497H mice, likely constituting a cellular mechanism for the cognitive impairments. Because these alterations are detectable before the establishment of overt pathology, we hypothesize that they may affect the further course of the disease.
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Affiliation(s)
- Daniel Radzicki
- Department of Physiology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
| | - Erdong Liu
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
| | - Han-Xiang Deng
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
| | - Teepu Siddique
- Department of Neurology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
| | - Marco Martina
- Department of Physiology, Northwestern University Feinberg School of Medicine Chicago, IL, USA
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118
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Advancing the understanding of autism disease mechanisms through genetics. Nat Med 2016; 22:345-61. [PMID: 27050589 DOI: 10.1038/nm.4071] [Citation(s) in RCA: 513] [Impact Index Per Article: 64.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 02/26/2016] [Indexed: 12/11/2022]
Abstract
Progress in understanding the genetic etiology of autism spectrum disorders (ASD) has fueled remarkable advances in our understanding of its potential neurobiological mechanisms. Yet, at the same time, these findings highlight extraordinary causal diversity and complexity at many levels ranging from molecules to circuits and emphasize the gaps in our current knowledge. Here we review current understanding of the genetic architecture of ASD and integrate genetic evidence, neuropathology and studies in model systems with how they inform mechanistic models of ASD pathophysiology. Despite the challenges, these advances provide a solid foundation for the development of rational, targeted molecular therapies.
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119
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Getz AM, Visser F, Bell EM, Xu F, Flynn NM, Zaidi W, Syed NI. Two proteolytic fragments of menin coordinate the nuclear transcription and postsynaptic clustering of neurotransmitter receptors during synaptogenesis between Lymnaea neurons. Sci Rep 2016; 6:31779. [PMID: 27538741 PMCID: PMC4990912 DOI: 10.1038/srep31779] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 07/27/2016] [Indexed: 12/20/2022] Open
Abstract
Synapse formation and plasticity depend on nuclear transcription and site-specific protein targeting, but the molecular mechanisms that coordinate these steps have not been well defined. The MEN1 tumor suppressor gene, which encodes the protein menin, is known to induce synapse formation and plasticity in the CNS. This synaptogenic function has been conserved across evolution, however the underlying molecular mechanisms remain unidentified. Here, using central neurons from the invertebrate Lymnaea stagnalis, we demonstrate that menin coordinates subunit-specific transcriptional regulation and synaptic clustering of nicotinic acetylcholine receptors (nAChR) during neurotrophic factor (NTF)-dependent excitatory synaptogenesis, via two proteolytic fragments generated by calpain cleavage. Whereas menin is largely regarded as a nuclear protein, our data demonstrate a novel cytoplasmic function at central synapses. Furthermore, this study identifies a novel synaptogenic mechanism in which a single gene product coordinates the nuclear transcription and postsynaptic targeting of neurotransmitter receptors through distinct molecular functions of differentially localized proteolytic fragments.
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Affiliation(s)
- Angela M Getz
- Department of Cell Biology &Anatomy, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.,Department of Neuroscience, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Frank Visser
- Department of Physiology &Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Erin M Bell
- Department of Cell Biology &Anatomy, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Fenglian Xu
- Department of Physiology &Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.,Department of Biology, Saint Louis University, Saint Louis, Missouri, 63103, USA
| | - Nichole M Flynn
- Department of Cell Biology &Anatomy, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada.,Department of Neuroscience, Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Wali Zaidi
- Department of Cell Biology &Anatomy, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
| | - Naweed I Syed
- Department of Cell Biology &Anatomy, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, T2N 1N4, Canada
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120
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Anglada-Huguet M, Giralt A, Rué L, Alberch J, Xifró X. Loss of striatal 90-kDa ribosomal S6 kinase (Rsk) is a key factor for motor, synaptic and transcription dysfunction in Huntington's disease. Biochim Biophys Acta Mol Basis Dis 2016; 1862:1255-66. [DOI: 10.1016/j.bbadis.2016.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Revised: 03/09/2016] [Accepted: 04/03/2016] [Indexed: 12/20/2022]
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121
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Ben-Hail D, Shoshan-Barmatz V. VDAC1-interacting anion transport inhibitors inhibit VDAC1 oligomerization and apoptosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1612-23. [DOI: 10.1016/j.bbamcr.2016.04.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 03/01/2016] [Accepted: 04/06/2016] [Indexed: 10/22/2022]
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122
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Brzdąk P, Włodarczyk J, Mozrzymas JW, Wójtowicz T. Matrix Metalloprotease 3 Activity Supports Hippocampal EPSP-to-Spike Plasticity Following Patterned Neuronal Activity via the Regulation of NMDAR Function and Calcium Flux. Mol Neurobiol 2016; 54:804-816. [PMID: 27351676 PMCID: PMC5219885 DOI: 10.1007/s12035-016-9970-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/08/2016] [Indexed: 01/01/2023]
Abstract
Matrix metalloproteases (MMPs) comprise a family of endopeptidases that are involved in remodeling the extracellular matrix and play a critical role in learning and memory. At least 24 different MMP subtypes have been identified in the human brain, but less is known about the subtype-specific actions of MMP on neuronal plasticity. The long-term potentiation (LTP) of excitatory synaptic transmission and scaling of dendritic and somatic neuronal excitability are considered substrates of memory storage. We previously found that MMP-3 and MMP-2/9 may be differentially involved in shaping the induction and expression of excitatory postsynaptic potential (EPSP)-to-spike (E-S) potentiation in hippocampal brain slices. MMP-3 and MMP-2/9 proteolysis was previously shown to affect the integrity or mobility of synaptic N-methyl-d-aspartate receptors (NMDARs) in vitro. However, the functional outcome of such MMP-NMDAR interactions remains largely unknown. The present study investigated the role of these MMP subtypes in E-S plasticity and NMDAR function in mouse hippocampal acute brain slices. The temporal requirement for MMP-3/NMDAR activity in E-S potentiation within the CA1 field largely overlapped, and MMP-3 but not MMP-2/9 activity was crucial for the gain-of-function of NMDARs following LTP induction. Functional changes in E-S plasticity following MMP-3 inhibition largely correlated with the expression of cFos protein, a marker of activity-related gene transcription. Recombinant MMP-3 promoted a gain in NMDAR-mediated field potentials and somatodendritic Ca2+ waves. These results suggest that long-term hippocampal E-S potentiation requires transient MMP-3 activity that promotes NMDAR-mediated postsynaptic Ca2+ entry that is vital for the activation of downstream signaling cascades and gene transcription.
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Affiliation(s)
- Patrycja Brzdąk
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Chalubinskiego 3, Wroclaw, 50-368, Poland.,Department of Animal Molecular Physiology, Institute of Experimental Biology, Wroclaw University, Wroclaw, Poland
| | - Jakub Włodarczyk
- Laboratory of Cell Biophysics, Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Jerzy W Mozrzymas
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Chalubinskiego 3, Wroclaw, 50-368, Poland.,Department of Animal Molecular Physiology, Institute of Experimental Biology, Wroclaw University, Wroclaw, Poland
| | - Tomasz Wójtowicz
- Laboratory of Neuroscience, Department of Biophysics, Wroclaw Medical University, Chalubinskiego 3, Wroclaw, 50-368, Poland.
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123
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Zhu Τ, Liang C, Li D, Tian M, Liu S, Gao G, Guan JS. Histone methyltransferase Ash1L mediates activity-dependent repression of neurexin-1α. Sci Rep 2016; 6:26597. [PMID: 27229316 PMCID: PMC4882582 DOI: 10.1038/srep26597] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 05/05/2016] [Indexed: 11/09/2022] Open
Abstract
Activity-dependent transcription is critical for the regulation of long-term synaptic plasticity and plastic rewiring in the brain. Here, we report that the transcription of neurexin1α (nrxn1α), a presynaptic adhesion molecule for synaptic formation, is regulated by transient neuronal activation. We showed that 10 minutes of firing at 50 Hz in neurons repressed the expression of nrxn1α for 24 hours in a primary cortical neuron culture through a transcriptional repression mechanism. By performing a screening assay using a synthetic zinc finger protein (ZFP) to pull down the proteins enriched near the nrxn1α promoter region in vivo, we identified that Ash1L, a histone methyltransferase, is enriched in the nrxn1α promoter. Neuronal activity triggered binding of Ash1L to the promoter and enriched the histone marker H3K36me2 at the nrxn1α promoter region. Knockout of Ash1L in mice completely abolished the activity-dependent repression of nrxn1α. Taken together, our results reveal that a novel process of activity-dependent transcriptional repression exists in neurons and that Ash1L mediates the long-term repression of nrxn1α, thus implicating an important role for epigenetic modification in brain functioning.
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Affiliation(s)
- Τao Zhu
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Chen Liang
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Dongdong Li
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Miaomiao Tian
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Sanxiong Liu
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Guanjun Gao
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
| | - Ji-Song Guan
- MOE Key Laboratory of Protein Sciences, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Center for Brain-Inspired Computing Research, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, China
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124
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Sun F, Nguyen T, Jin X, Huang R, Chen Z, Cunningham RL, Singh M, Su C. Pgrmc1/BDNF Signaling Plays a Critical Role in Mediating Glia-Neuron Cross Talk. Endocrinology 2016; 157:2067-79. [PMID: 26990062 PMCID: PMC4870882 DOI: 10.1210/en.2015-1610] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Progesterone (P4) exerts robust cytoprotection in brain slice cultures (containing both neurons and glia), yet such protection is not as evident in neuron-enriched cultures, suggesting that glia may play an indispensable role in P4's neuroprotection. We previously reported that a membrane-associated P4 receptor, P4 receptor membrane component 1, mediates P4-induced brain-derived neurotrophic factor (BDNF) release from glia. Here, we sought to determine whether glia are required for P4's neuroprotection and whether glia's roles are mediated, at least partially, via releasing soluble factors to act on neighboring neurons. Our data demonstrate that P4 increased the level of mature BDNF (neuroprotective) while decreasing pro-BDNF (potentially neurotoxic) in the conditioned media (CMs) of cultured C6 astrocytes. We examined the effects of CMs derived from P4-treated astrocytes (P4-CMs) on 2 neuronal models: 1) all-trans retinoid acid-differentiated SH-SY5Y cells and 2) mouse primary hippocampal neurons. P4-CM increased synaptic marker expression and promoted neuronal survival against H2O2. These effects were attenuated by Y1036 (an inhibitor of neurotrophin receptor [tropomysin-related kinase] signaling), as well as tropomysin-related kinase B-IgG (a more specific inhibitor to block BDNF signaling), which pointed to BDNF as the key protective component within P4-CM. These findings suggest that P4 may exert its maximal protection by triggering a glia-neuron cross talk, in which P4 promotes mature BDNF release from glia to enhance synaptogenesis as well as survival of neurons. This recognition of the importance of glia in mediating P4's neuroprotection may also inform the design of effective therapeutic methods for treating diseases wherein neuronal death and/or synaptic deficits are noted.
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Affiliation(s)
- Fen Sun
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Trinh Nguyen
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Xin Jin
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Renqi Huang
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Zhenglan Chen
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Rebecca L Cunningham
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Meharvan Singh
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
| | - Chang Su
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas 76107
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125
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González B, Rivero-Echeto C, Muñiz JA, Cadet JL, García-Rill E, Urbano FJ, Bisagno V. Methamphetamine blunts Ca(2+) currents and excitatory synaptic transmission through D1/5 receptor-mediated mechanisms in the mouse medial prefrontal cortex. Addict Biol 2016; 21:589-602. [PMID: 25871318 DOI: 10.1111/adb.12249] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Psychostimulant addiction is associated with dysfunctions in frontal cortex. Previous data demonstrated that repeated exposure to methamphetamine (METH) can alter prefrontal cortex (PFC)-dependent functions. Here, we show that withdrawal from repetitive non-contingent METH administration (7 days, 1 mg/kg) depressed voltage-dependent calcium currents (ICa ) and increased hyperpolarization-activated cation current (IH ) amplitude and the paired-pulse ratio of evoked excitatory postsynaptic currents (EPSCs) in deep-layer pyramidal mPFC neurons. Most of these effects were blocked by systemic co-administration of the D1/D5 receptor antagonist SCH23390 (0.5 and 0.05 mg/kg). In vitro METH (i.e. bath-applied to slices from naïve-treated animals) was able to emulate its systemic effects on ICa and evoked EPSCs paired-pulse ratio. We also provide evidence of altered mRNA expression of (1) voltage-gated calcium channels P/Q-type Cacna1a (Cav 2.1), N-type Cacna1b (Cav 2.2), T-type Cav 3.1 Cacna1g, Cav 3.2 Cacna1h, Cav 3.3 Cacna1i and the auxiliary subunit Cacna2d1 (α2δ1); (2) hyperpolarization-activated cyclic nucleotide-gated channels Hcn1 and Hcn2; and (3) glutamate receptors subunits AMPA-type Gria1, NMDA-type Grin1 and metabotropic Grm1 in the mouse mPFC after repeated METH treatment. Moreover, we show that some of these changes in mRNA expression were sensitive D1/5 receptor blockade. Altogether, these altered mechanisms affecting synaptic physiology and transcriptional regulation may underlie PFC functional alterations that could lead to PFC impairments observed in METH-addicted individuals.
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Affiliation(s)
- Betina González
- Instituto de Investigaciones Farmacológicas; Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
| | - Celeste Rivero-Echeto
- Laboratorio de Fisiología y Biología Molecular; Instituto de Fisiología, Biología Molecular y Neurociencias; Departamento de Fisiología, Biología Molecular y Celular ‘Dr. Hector Maldonado’ (DFBMC); Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
| | - Javier A. Muñiz
- Instituto de Investigaciones Farmacológicas; Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
| | - Jean Lud Cadet
- Molecular Neuropsychiatry Research Branch; NIH/NIDA Intramural Research Program; Baltimore MD USA
| | - Edgar García-Rill
- Center for Translational Neuroscience; Department of Neurobiology and Developmental Sciences; University of Arkansas for Medical Sciences; Little Rock AR USA
| | - Francisco J. Urbano
- Laboratorio de Fisiología y Biología Molecular; Instituto de Fisiología, Biología Molecular y Neurociencias; Departamento de Fisiología, Biología Molecular y Celular ‘Dr. Hector Maldonado’ (DFBMC); Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
| | - Verónica Bisagno
- Instituto de Investigaciones Farmacológicas; Universidad de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
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126
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Schorova L, Martin S. Sumoylation in Synaptic Function and Dysfunction. Front Synaptic Neurosci 2016; 8:9. [PMID: 27199730 PMCID: PMC4848311 DOI: 10.3389/fnsyn.2016.00009] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/08/2016] [Indexed: 12/18/2022] Open
Abstract
Sumoylation has recently emerged as a key post-translational modification involved in many, if not all, biological processes. Small Ubiquitin-like Modifier (SUMO) polypeptides are covalently attached to specific lysine residues of target proteins through a dedicated enzymatic pathway. Disruption of the SUMO enzymatic pathway in the developing brain leads to lethality indicating that this process exerts a central role during embryonic and post-natal development. However, little is still known regarding how this highly dynamic protein modification is regulated in the mammalian brain despite an increasing number of data implicating sumoylated substrates in synapse formation, synaptic communication and plasticity. The aim of this review is therefore to briefly describe the enzymatic SUMO pathway and to give an overview of our current knowledge on the function and dysfunction of protein sumoylation at the mammalian synapse.
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Affiliation(s)
- Lenka Schorova
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
| | - Stéphane Martin
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
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127
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Excitation-Transcription Coupling in Parvalbumin-Positive Interneurons Employs a Novel CaM Kinase-Dependent Pathway Distinct from Excitatory Neurons. Neuron 2016; 90:292-307. [PMID: 27041500 DOI: 10.1016/j.neuron.2016.03.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 11/23/2015] [Accepted: 02/24/2016] [Indexed: 11/20/2022]
Abstract
Properly functional CNS circuits depend on inhibitory interneurons that in turn rely upon activity-dependent gene expression for morphological development, connectivity, and excitatory-inhibitory coordination. Despite its importance, excitation-transcription coupling in inhibitory interneurons is poorly understood. We report that PV+ interneurons employ a novel CaMK-dependent pathway to trigger CREB phosphorylation and gene expression. As in excitatory neurons, voltage-gated Ca(2+) influx through CaV1 channels triggers CaM nuclear translocation via local Ca(2+) signaling. However, PV+ interneurons are distinct in that nuclear signaling is mediated by γCaMKI, not γCaMKII. CREB phosphorylation also proceeds with slow, sigmoid kinetics, rate-limited by paucity of CaMKIV, protecting against saturation of phospho-CREB in the face of higher firing rates and bigger Ca(2+) transients. Our findings support the generality of CaM shuttling to drive nuclear CaMK activity, and they are relevant to disease pathophysiology, insofar as dysfunction of PV+ interneurons and molecules underpinning their excitation-transcription coupling both relate to neuropsychiatric disease.
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128
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Abstract
The immediate early gene c-fos has long been known as a molecular marker of neural activity. The neuron's activity is transformed into intracellular calcium influx through NMDA receptors and L-type voltage sensitive calcium channels. For the transcription of c-fos, neural activity should be strong enough to activate mitogen-activated protein kinase (MAPK) signaling pathway which shows low calcium sensitivity. Upon translation, the auto-inhibition by Fos protein regulates basal Fos expression. The pattern of external stimuli and the valence of the stimulus to the animal change Fos signal, thus the signal reflects learning and memory aspects. Understanding the features of multiple components regulating Fos signaling is necessary for the optimal generation and interpretation of Fos signal.
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Affiliation(s)
- Leeyup Chung
- Dept. of Neurobiology, Duke University School of Medicine, Durham, NC, USA
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129
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Alsina FC, Hita FJ, Fontanet PA, Irala D, Hedman H, Ledda F, Paratcha G. Lrig1 is a cell-intrinsic modulator of hippocampal dendrite complexity and BDNF signaling. EMBO Rep 2016; 17:601-16. [PMID: 26935556 DOI: 10.15252/embr.201541218] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/28/2016] [Indexed: 11/09/2022] Open
Abstract
Even though many extracellular factors have been identified as promoters of general dendritic growth and branching, little is known about the cell-intrinsic modulators that allow neurons to sculpt distinctive patterns of dendrite arborization. Here, we identify Lrig1, a nervous system-enriched LRR protein, as a key physiological regulator of dendrite complexity of hippocampal pyramidal neurons. Lrig1-deficient mice display morphological changes in proximal dendrite arborization and defects in social interaction. Specifically, knockdown of Lrig1 enhances both primary dendrite formation and proximal dendritic branching of hippocampal neurons, two phenotypes that resemble the effect of BDNF on these neurons. In addition, we show that Lrig1 physically interacts with TrkB and attenuates BDNF signaling. Gain and loss of function assays indicate that Lrig1 restricts BDNF-induced dendrite morphology. Together, our findings reveal a novel and essential role of Lrig1 in regulating morphogenic events that shape the hippocampal circuits and establish that the assembly of TrkB with Lrig1 represents a key mechanism for understanding how specific neuronal populations expand the repertoire of responses to BDNF during brain development.
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Affiliation(s)
- Fernando Cruz Alsina
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Francisco Javier Hita
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Paula Aldana Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Dolores Irala
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Håkan Hedman
- Oncology Research Laboratory, Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Fernanda Ledda
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
| | - Gustavo Paratcha
- Division of Molecular and Cellular Neuroscience, Institute of Cell Biology and Neuroscience (IBCN)-CONICET School of Medicine University of Buenos Aires (UBA), Buenos Aires, Argentina
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130
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Stanzel S, Stubbusch J, Pataskar A, Howard MJ, Deller T, Ernsberger U, Tiwari VK, Rohrer H, Tsarovina K. Distinct roles of hand2 in developing and adult autonomic neurons. Dev Neurobiol 2016; 76:1111-24. [PMID: 26818017 DOI: 10.1002/dneu.22378] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/05/2016] [Accepted: 01/07/2016] [Indexed: 11/08/2022]
Abstract
The bHLH transcription factor Hand2 is essential for the acquisition and maintenance of noradrenergic properties of embryonic sympathetic neurons and controls neuroblast proliferation. Hand2 is also expressed in embryonic and postnatal parasympathetic ganglia and remains expressed in sympathetic neurons up to the adult stage. Here, we address its function in developing parasympathetic and adult sympathetic neurons. We conditionally deleted Hand2 in the parasympathetic sphenopalatine ganglion by crossing a line of floxed Hand2 mice with DbhiCre transgenic mice, taking advantage of the transient Dbh expression in parasympathetic ganglia. Hand2 elimination does not affect Dbh expression and sphenopalatine ganglion size at E12.5 and E16.5, in contrast to sympathetic ganglia. These findings demonstrate different functions for Hand2 in the parasympathetic and sympathetic lineage. Our previous Hand2 knockdown in postmitotic, differentiated chick sympathetic neurons resulted in decreased expression of noradrenergic marker genes but it was unclear whether Hand2 is required for maintaining noradrenergic neuron identity in adult animals. We now show that Hand2 elimination in adult Dbh-expressing sympathetic neurons does not decrease the expression of Th and Dbh, in contrast to the situation during development. However, gene expression profiling of adult sympathetic neurons identified 75 Hand2-dependent target genes. Interestingly, a notable proportion of down-regulated genes (15%) encode for proteins with synaptic and neurotransmission functions. These results demonstrate a change in Hand2 target genes during maturation of sympathetic neurons. Whereas Hand2 controls genes regulating noradrenergic differentiation during development, Hand2 seems to be involved in the regulation of genes controlling neurotransmission in adult sympathetic neurons. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1111-1124, 2016.
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Affiliation(s)
- Sabine Stanzel
- Developmental Neurobiology, Max-Planck-Institute for Brain Research, Max-von-Laue-Str. 4, Frankfurt/M, 60438, Germany
| | - Jutta Stubbusch
- Developmental Neurobiology, Max-Planck-Institute for Brain Research, Max-von-Laue-Str. 4, Frankfurt/M, 60438, Germany
| | - Abhijeet Pataskar
- Institute of Molecular Biology (IMB) Boehringer Ingelheim Foundation, Ackermannweg 4, Mainz, 55128, Germany
| | - Marthe J Howard
- Department of Neurosciences and Program in Neurosciences and Neurological Disorders, University of Toledo Health Sciences Campus, Toledo, Ohio, 43614
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Goethe University Frankfurt/M, Theodor-Stern-Kai 7, Frankfurt/M, 60590, Germany
| | - Uwe Ernsberger
- Developmental Neurobiology, Max-Planck-Institute for Brain Research, Max-von-Laue-Str. 4, Frankfurt/M, 60438, Germany.,Institute of Clinical Neuroanatomy, Goethe University Frankfurt/M, Theodor-Stern-Kai 7, Frankfurt/M, 60590, Germany.,Ernst-Strüngmann-Institute, Deutschordenstr. 46, Frankfurt/M, 60528, Germany
| | - Vijay K Tiwari
- Institute of Molecular Biology (IMB) Boehringer Ingelheim Foundation, Ackermannweg 4, Mainz, 55128, Germany
| | - Hermann Rohrer
- Developmental Neurobiology, Max-Planck-Institute for Brain Research, Max-von-Laue-Str. 4, Frankfurt/M, 60438, Germany.,Institute of Clinical Neuroanatomy, Goethe University Frankfurt/M, Theodor-Stern-Kai 7, Frankfurt/M, 60590, Germany.,Ernst-Strüngmann-Institute, Deutschordenstr. 46, Frankfurt/M, 60528, Germany
| | - Konstantina Tsarovina
- Developmental Neurobiology, Max-Planck-Institute for Brain Research, Max-von-Laue-Str. 4, Frankfurt/M, 60438, Germany
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131
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Katz DM, Bird A, Coenraads M, Gray SJ, Menon DU, Philpot BD, Tarquinio DC. Rett Syndrome: Crossing the Threshold to Clinical Translation. Trends Neurosci 2016; 39:100-113. [PMID: 26830113 PMCID: PMC4924590 DOI: 10.1016/j.tins.2015.12.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/14/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Lying at the intersection between neurobiology and epigenetics, Rett syndrome (RTT) has garnered intense interest in recent years, not only from a broad range of academic scientists, but also from the pharmaceutical and biotechnology industries. In addition to the critical need for treatments for this devastating disorder, optimism for developing RTT treatments derives from a unique convergence of factors, including a known monogenic cause, reversibility of symptoms in preclinical models, a strong clinical research infrastructure highlighted by an NIH-funded natural history study and well-established clinics with significant patient populations. Here, we review recent advances in understanding the biology of RTT, particularly promising preclinical findings, lessons from past clinical trials, and critical elements of trial design for rare disorders.
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Affiliation(s)
- David M Katz
- Departments of Neurosciences and Psychiatry, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
| | - Adrian Bird
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Monica Coenraads
- Rett Syndrome Research Trust, 67 Under Cliff Road, Trumbull, CT 06611, USA
| | - Steven J Gray
- Gene Therapy Center and Department of Ophthalmology, University of North Carolina, Chapel Hill, NC USA
| | - Debashish U Menon
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology, Neuroscience Center, and Carolina Institute for Developmental Disabilities, UNC School of Medicine, Chapel Hill, NC 27599, USA
| | - Daniel C Tarquinio
- Children's Healthcare of Atlanta, Emory University, 1605 Chantilly Drive NE, Atlanta, GA 30324, USA
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132
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Synaptic Wnt/GSK3β Signaling Hub in Autism. Neural Plast 2016; 2016:9603751. [PMID: 26881141 PMCID: PMC4736967 DOI: 10.1155/2016/9603751] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 11/29/2015] [Accepted: 11/30/2015] [Indexed: 12/29/2022] Open
Abstract
Hundreds of genes have been associated with autism spectrum disorders (ASDs) and the interaction of weak and de novo variants derive from distinct autistic phenotypes thus making up the “spectrum.” The convergence of these variants in networks of genes associated with synaptic function warrants the study of cell signaling pathways involved in the regulation of the synapse. The Wnt/β-catenin signaling pathway plays a central role in the development and regulation of the central nervous system and several genes belonging to the cascade have been genetically associated with ASDs. In the present paper, we review basic information regarding the role of Wnt/β-catenin signaling in excitatory/inhibitory balance (E/I balance) through the regulation of pre- and postsynaptic compartments. Furthermore, we integrate information supporting the role of the glycogen synthase kinase 3β (GSK3β) in the onset/development of ASDs through direct modulation of Wnt/β-catenin signaling. Finally, given GSK3β activity as key modulator of synaptic plasticity, we explore the potential of this kinase as a therapeutic target for ASD.
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133
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KCC2 rescues functional deficits in human neurons derived from patients with Rett syndrome. Proc Natl Acad Sci U S A 2016; 113:751-6. [PMID: 26733678 DOI: 10.1073/pnas.1524013113] [Citation(s) in RCA: 150] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome is a severe form of autism spectrum disorder, mainly caused by mutations of a single gene methyl CpG binding protein 2 (MeCP2) on the X chromosome. Patients with Rett syndrome exhibit a period of normal development followed by regression of brain function and the emergence of autistic behaviors. However, the mechanism behind the delayed onset of symptoms is largely unknown. Here we demonstrate that neuron-specific K(+)-Cl(-) cotransporter2 (KCC2) is a critical downstream gene target of MeCP2. We found that human neurons differentiated from induced pluripotent stem cells from patients with Rett syndrome showed a significant deficit in KCC2 expression and consequently a delayed GABA functional switch from excitation to inhibition. Interestingly, overexpression of KCC2 in MeCP2-deficient neurons rescued GABA functional deficits, suggesting an important role of KCC2 in Rett syndrome. We further identified that RE1-silencing transcriptional factor, REST, a neuronal gene repressor, mediates the MeCP2 regulation of KCC2. Because KCC2 is a slow onset molecule with expression level reaching maximum later in development, the functional deficit of KCC2 may offer an explanation for the delayed onset of Rett symptoms. Our studies suggest that restoring KCC2 function in Rett neurons may lead to a potential treatment for Rett syndrome.
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134
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Rauch AK, Rosskothen-Kuhl N, Illing RB. Counter-regulation of the AP-1 monomers pATF2 and Fos: Molecular readjustment of brainstem neurons in hearing and deaf adult rats after electrical intracochlear stimulation. Neuroscience 2016; 313:184-98. [DOI: 10.1016/j.neuroscience.2015.11.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 10/09/2015] [Accepted: 11/12/2015] [Indexed: 12/24/2022]
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135
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Disrupted in schizophrenia 1 (DISC1) L100P mutants have impaired activity-dependent plasticity in vivo and in vitro. Transl Psychiatry 2016; 6:e712. [PMID: 26756905 PMCID: PMC5068880 DOI: 10.1038/tp.2015.206] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 10/30/2015] [Indexed: 12/26/2022] Open
Abstract
Major neuropsychiatric disorders are genetically complex but share overlapping etiology. Mice mutant for rare, highly penetrant risk variants can be useful in dissecting the molecular mechanisms involved. The gene disrupted in schizophrenia 1 (DISC1) has been associated with increased risk for neuropsychiatric conditions. Mice mutant for Disc1 display morphological, functional and behavioral deficits that are consistent with impairments observed across these disorders. Here we report that Disc1 L100P mutants are less able to reorganize cortical circuitry in response to stimulation in vivo. Molecular analysis reveals that the mutants have a reduced expression of PSD95 and pCREB in visual cortex and fail to adjust expression of such markers in response to altered stimulation. In vitro analysis shows that mutants have impaired functional reorganization of cortical neurons in response to selected forms of neuronal stimulation, but there is no altered basal expression of synaptic markers. These findings suggest that DISC1 has a critical role in the reorganization of cortical plasticity and that this phenotype becomes evident only under challenge, even at early postnatal stages. This result may represent an important etiological mechanism in the emergence of neuropsychiatric disorders.
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136
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Sun MY, Izumi Y, Benz A, Zorumski CF, Mennerick S. Endogenous 24S-hydroxycholesterol modulates NMDAR-mediated function in hippocampal slices. J Neurophysiol 2015; 115:1263-72. [PMID: 26745248 DOI: 10.1152/jn.00890.2015] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/18/2015] [Indexed: 11/22/2022] Open
Abstract
N-methyl-D-aspartate receptors (NMDARs), a major subtype of glutamate receptors mediating excitatory transmission throughout the central nervous system (CNS), play critical roles in governing brain function and cognition. Because NMDAR dysfunction contributes to the etiology of neurological and psychiatric disorders including stroke and schizophrenia, NMDAR modulators are potential drug candidates. Our group recently demonstrated that the major brain cholesterol metabolite, 24S-hydroxycholesterol (24S-HC), positively modulates NMDARs when exogenously administered. Here, we studied whether endogenous 24S-HC regulates NMDAR activity in hippocampal slices. In CYP46A1(-/-) (knockout; KO) slices where endogenous 24S-HC is greatly reduced, NMDAR tone, measured as NMDAR-to-α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) excitatory postsynaptic current (EPSC) ratio, was reduced. This difference translated into more NMDAR-driven spiking in wild-type (WT) slices compared with KO slices. Application of SGE-301, a 24S-HC analog, had comparable potentiating effects on NMDAR EPSCs in both WT and KO slices, suggesting that endogenous 24S-HC does not saturate its NMDAR modulatory site in ex vivo slices. KO slices did not differ from WT slices in either spontaneous neurotransmission or in neuronal intrinsic excitability, and exhibited LTP indistinguishable from WT slices. However, KO slices exhibited higher resistance to persistent NMDAR-dependent depression of synaptic transmission induced by oxygen-glucose deprivation (OGD), an effect restored by SGE-301. Together, our results suggest that loss of positive NMDAR tone does not elicit compensatory changes in excitability or transmission, but it protects transmission against NMDAR-mediated dysfunction. We expect that manipulating this endogenous NMDAR modulator may offer new treatment strategies for neuropsychiatric dysfunction.
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Affiliation(s)
- Min-Yu Sun
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Yukitoshi Izumi
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
| | - Ann Benz
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri
| | - Charles F Zorumski
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri; and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
| | - Steven Mennerick
- Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri; Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri; and Taylor Family Institute for Innovative Psychiatric Research, Washington University School of Medicine, St. Louis, Missouri
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137
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Hou S, Carson DM, Wu D, Klaw MC, Houlé JD, Tom VJ. Dopamine is produced in the rat spinal cord and regulates micturition reflex after spinal cord injury. Exp Neurol 2015; 285:136-146. [PMID: 26655672 DOI: 10.1016/j.expneurol.2015.12.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/29/2015] [Accepted: 12/01/2015] [Indexed: 12/13/2022]
Abstract
Dopamine (DA) neurons in the mammalian central nervous system are thought to be restricted to the brain. DA-mediated regulation of urinary activity is considered to occur through an interaction between midbrain DA neurons and the pontine micturition center. Here we show that DA is produced in the rat spinal cord and modulates the bladder reflex. We observed numerous tyrosine hydroxylase (TH)+ neurons in the autonomic nuclei and superficial dorsal horn in L6-S3 spinal segments. These neurons are dopamine-β-hydroxylase (DBH)- and some contain detectable dopamine decarboxylase (DDC), suggesting their capacity to produce DA. Interestingly, following a complete thoracic spinal cord injury (SCI) to interrupt supraspinal projections, more TH+ neurons emerged in the lumbosacral spinal cord, coincident with a sustained, low level of DA expression there and a partially recovered micturition reflex. Non-selective blockade of spinal DA receptors reduced bladder activity whereas activation of spinal D2-like receptors increased bladder activity and facilitated voiding. Additionally, depletion of lumbosacral TH+ neurons with 6-hydroxydopamine (6-OHDA) decreased bladder non-voiding contractions and voiding efficiency. Furthermore, injecting the transsynaptic neuronal tracer pseudorabies virus (PRV) into the bladder detrusor labeled TH+ cells in the lumbosacral cord, confirming their involvement in spinal micturition reflex circuits. These results illustrate that DA is synthesized in the rat spinal cord; plasticity of lumbosacral TH+ neurons following SCI may contribute to DA expression and modulate the spinal bladder reflex. Thus, spinally-derived DA and receptors could be a novel therapeutic target to improve micturition recovery after SCI.
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MESH Headings
- Animals
- Animals, Newborn
- Choline O-Acetyltransferase/metabolism
- Disease Models, Animal
- Dopamine/analogs & derivatives
- Dopamine/metabolism
- Dopamine Agents/pharmacology
- Enzyme-Linked Immunosorbent Assay
- Female
- Ganglia, Parasympathetic/pathology
- Ganglia, Sympathetic/pathology
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Herpesvirus 1, Suid/genetics
- Herpesvirus 1, Suid/metabolism
- Neurons/metabolism
- Oxidopamine/toxicity
- Rats
- Rats, Inbred F344
- Rats, Sprague-Dawley
- Rats, Wistar
- Reflex/physiology
- Spinal Cord/metabolism
- Spinal Cord/physiopathology
- Spinal Cord Injuries/chemically induced
- Spinal Cord Injuries/pathology
- Spinal Cord Injuries/physiopathology
- Stilbamidines/pharmacokinetics
- Thiocarbamates/metabolism
- Transduction, Genetic
- Tyrosine 3-Monooxygenase/metabolism
- Urinary Bladder/innervation
- Urinary Bladder/physiopathology
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Affiliation(s)
- Shaoping Hou
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States.
| | - David M Carson
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States
| | - Di Wu
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States
| | - Michelle C Klaw
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States
| | - John D Houlé
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States
| | - Veronica J Tom
- Spinal Cord Research Center, Department of Neurobiology & Anatomy, Drexel University College of Medicine, Philadelphia, PA 19129, United States.
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138
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Borovok N, Nesher E, Levin Y, Reichenstein M, Pinhasov A, Michaelevski I. Dynamics of Hippocampal Protein Expression During Long-term Spatial Memory Formation. Mol Cell Proteomics 2015; 15:523-41. [PMID: 26598641 DOI: 10.1074/mcp.m115.051318] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Indexed: 01/08/2023] Open
Abstract
Spatial memory depends on the hippocampus, which is particularly vulnerable to aging. This vulnerability has implications for the impairment of navigation capacities in older people, who may show a marked drop in performance of spatial tasks with advancing age. Contemporary understanding of long-term memory formation relies on molecular mechanisms underlying long-term synaptic plasticity. With memory acquisition, activity-dependent changes occurring in synapses initiate multiple signal transduction pathways enhancing protein turnover. This enhancement facilitates de novo synthesis of plasticity related proteins, crucial factors for establishing persistent long-term synaptic plasticity and forming memory engrams. Extensive studies have been performed to elucidate molecular mechanisms of memory traces formation; however, the identity of plasticity related proteins is still evasive. In this study, we investigated protein turnover in mouse hippocampus during long-term spatial memory formation using the reference memory version of radial arm maze (RAM) paradigm. We identified 1592 proteins, which exhibited a complex picture of expression changes during spatial memory formation. Variable linear decomposition reduced significantly data dimensionality and enriched three principal factors responsible for variance of memory-related protein levels at (1) the initial phase of memory acquisition (165 proteins), (2) during the steep learning improvement (148 proteins), and (3) the final phase of the learning curve (123 proteins). Gene ontology and signaling pathways analysis revealed a clear correlation between memory improvement and learning phase-curbed expression profiles of proteins belonging to specific functional categories. We found differential enrichment of (1) neurotrophic factors signaling pathways, proteins regulating synaptic transmission, and actin microfilament during the first day of the learning curve; (2) transcription and translation machinery, protein trafficking, enhancement of metabolic activity, and Wnt signaling pathway during the steep phase of memory formation; and (3) cytoskeleton organization proteins. Taken together, this study clearly demonstrates dynamic assembly and disassembly of protein-protein interaction networks depending on the stage of memory formation engrams.
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Affiliation(s)
- Natalia Borovok
- From the ‡Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv 6997801, Israel
| | - Elimelech Nesher
- §Department of Molecular Biology, Ariel University, Ariel 4070000, Israel
| | - Yishai Levin
- ¶de Botton Institute for Protein Profiling, The Nancy & Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Michal Reichenstein
- From the ‡Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv 6997801, Israel
| | - Albert Pinhasov
- §Department of Molecular Biology, Ariel University, Ariel 4070000, Israel
| | - Izhak Michaelevski
- From the ‡Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel-Aviv 6997801, Israel; ‖Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
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139
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Cellular mechanisms of activity-dependent BDNF expression in primary sensory neurons. Neuroscience 2015; 310:665-73. [PMID: 26459016 DOI: 10.1016/j.neuroscience.2015.10.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 09/11/2015] [Accepted: 10/03/2015] [Indexed: 12/16/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) is abundantly expressed by both developing and adult rat visceral sensory neurons from the nodose ganglion (NG) in vivo and in vitro. We have previously shown that BDNF is released from neonatal NG neurons by activity and regulates dendritic development in their postsynaptic targets in the brainstem. The current study was carried out to examine the cellular and molecular mechanisms of activity-dependent BDNF expression in neonatal rat NG neurons, using our established in vitro model of neuronal activation by electrical field stimulation with patterns that mimic neuronal activity in vivo. We show that BDNF mRNA (transcript 4) increases over threefold in response to a 4-h tonic or bursting pattern delivered at the frequency of 6 Hz, which corresponds to the normal heart rate of a newborn rat. No significant increase in BDNF expression was observed following stimulation at 1 Hz. The latter effect suggests a frequency-dependent mechanism of regulated BDNF expression. In addition to BDNF transcript 4, which is known to be regulated by activity, transcript 1 also showed significant upregulation. The increases in BDNF mRNA were followed by BDNF protein upregulation of a similar magnitude after 24h of stimulation at 6 Hz. Electrical stimulation-evoked BDNF expression was inhibited by pretreating neurons with the blocker of voltage-gated sodium channels tetrodotoxin and by removing extracellular calcium. Moreover, our data show that repetitive stimulation-evoked BDNF expression requires calcium influx through N-, but not L-type, channels. Together, our study reveals novel mechanisms through which electrical activity stimulates de novo synthesis of BDNF in sensory neurons, and points to the role of N-type calcium channels in regulating BDNF expression in sensory neurons in response to repetitive stimulation.
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140
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Andrade e Silva B, Cassilhas RC, Attux C, Cordeiro Q, Gadelha AL, Telles BA, Bressan RA, Ferreira FN, Rodstein PH, Daltio CS, Tufik S, Mello MTD. A 20-week program of resistance or concurrent exercise improves symptoms of schizophrenia: results of a blind, randomized controlled trial. REVISTA BRASILEIRA DE PSIQUIATRIA 2015; 37:271-9. [DOI: 10.1590/1516-4446-2014-1595] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 02/10/2015] [Indexed: 02/01/2023]
Affiliation(s)
| | - Ricardo C. Cassilhas
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Brazil; UNIFESP, Brazil
| | | | - Quirino Cordeiro
- Faculdade de Ciências Médicas da Santa Casa de São Paulo, Brazil
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141
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Cohen SM, Tsien RW, Goff DC, Halassa MM. The impact of NMDA receptor hypofunction on GABAergic neurons in the pathophysiology of schizophrenia. Schizophr Res 2015; 167:98-107. [PMID: 25583246 PMCID: PMC4724170 DOI: 10.1016/j.schres.2014.12.026] [Citation(s) in RCA: 165] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 11/25/2014] [Accepted: 12/18/2014] [Indexed: 02/07/2023]
Abstract
While the dopamine hypothesis has dominated schizophrenia research for several decades, more recent studies have highlighted the role of fast synaptic transmitters and their receptors in schizophrenia etiology. Here we review evidence that schizophrenia is associated with a reduction in N-methyl-d-aspartate receptor (NMDAR) function. By highlighting postmortem, neuroimaging and electrophysiological studies, we provide evidence for preferential disruption of GABAergic circuits in the context of NMDAR hypo-activity states. The functional relationship between NMDARs and GABAergic neurons is realized at the molecular, cellular, microcircuit and systems levels. A synthesis of findings across these levels explains how NMDA-mediated inhibitory dysfunction may lead to aberrant interactions among brain regions, accounting for key clinical features of schizophrenia. This synthesis of schizophrenia unifies observations from diverse fields and may help chart pathways for developing novel diagnostics and therapeutics.
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Affiliation(s)
- Samuel M. Cohen
- NYU Neuroscience Institute and Department of Neuroscience and Physiology, NYU Langone Medical Center, New York, NY 10016, USA
| | - Richard W. Tsien
- NYU Neuroscience Institute and Department of Neuroscience and Physiology, NYU Langone Medical Center, New York, NY 10016, USA
| | - Donald C. Goff
- Department of Psychiatry, NYU Langone Medical Center, 550 First Avenue, New York City, NY 10016, USA
,Nathan Kline Institute for Psychiatric Research, 140 Old Orangeburg Road, Orangeburg, NY 10962, USA
| | - Michael M. Halassa
- NYU Neuroscience Institute and Department of Neuroscience and Physiology, NYU Langone Medical Center, New York, NY 10016, USA
,Department of Psychiatry, NYU Langone Medical Center, 550 First Avenue, New York City, NY 10016, USA
,To whom correspondence should be addressed:
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142
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Transcription factors FOXA1 and FOXA2 maintain dopaminergic neuronal properties and control feeding behavior in adult mice. Proc Natl Acad Sci U S A 2015; 112:E4929-38. [PMID: 26283356 DOI: 10.1073/pnas.1503911112] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Midbrain dopaminergic (mDA) neurons are implicated in cognitive functions, neuropsychiatric disorders, and pathological conditions; hence understanding genes regulating their homeostasis has medical relevance. Transcription factors FOXA1 and FOXA2 (FOXA1/2) are key determinants of mDA neuronal identity during development, but their roles in adult mDA neurons are unknown. We used a conditional knockout strategy to specifically ablate FOXA1/2 in mDA neurons of adult mice. We show that deletion of Foxa1/2 results in down-regulation of tyrosine hydroxylase, the rate-limiting enzyme of dopamine (DA) biosynthesis, specifically in dopaminergic neurons of the substantia nigra pars compacta (SNc). In addition, DA synthesis and striatal DA transmission were reduced after Foxa1/2 deletion. Furthermore, the burst-firing activity characteristic of SNc mDA neurons was drastically reduced in the absence of FOXA1/2. These molecular and functional alterations lead to a severe feeding deficit in adult Foxa1/2 mutant mice, independently of motor control, which could be rescued by L-DOPA treatment. FOXA1/2 therefore control the maintenance of molecular and physiological properties of SNc mDA neurons and impact on feeding behavior in adult mice.
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143
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Engrafted Neural Stem/Progenitor Cells Promote Functional Recovery through Synapse Reorganization with Spared Host Neurons after Spinal Cord Injury. Stem Cell Reports 2015; 5:264-77. [PMID: 26190527 PMCID: PMC4618657 DOI: 10.1016/j.stemcr.2015.06.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 06/16/2015] [Accepted: 06/16/2015] [Indexed: 12/26/2022] Open
Abstract
Neural stem/progenitor cell (NSPC) transplantation is a promising therapeutic strategy for spinal cord injury (SCI). However, the efficacy of NSPC transplantation on severe SCI is poorly understood. We herein show that NSPC transplantation promotes functional recovery after mild and moderate SCI, but not after severe SCI. In severe SCI mice, there were few remaining host neurons within the range of NSPC engraftment; thus, we examined whether the co-distribution of transplant and host is a contributory factor for functional improvement. A cellular selective analysis using laser microdissection revealed that drug-induced host neuronal ablation considerably decreased the synaptogenic potential of the engrafted NSPCs. Furthermore, following host neuronal ablation, neuronal retrograde tracing showed less propriospinal relay connections bridging the lesion after NSPC transplantation. Our findings suggest that the interactive synaptic reorganization between engrafted NSPCs and spared host neurons is crucial for functional recovery, providing significant insight for establishing therapeutic strategies for severe SCI.
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144
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Absence of plateau potentials in dLGN cells leads to a breakdown in retinogeniculate refinement. J Neurosci 2015; 35:3652-62. [PMID: 25716863 DOI: 10.1523/jneurosci.2343-14.2015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The link between neural activity and the refinement of projections from retina to the dorsal lateral geniculate nucleus (dLGN) of thalamus is based largely on studies that disrupt presynaptic retinogeniculate activity. Postsynaptic mechanisms responsible for implementing the activity-dependent remodeling in dLGN remain unknown. We tested whether L-type Ca(2+) channel activity in the form of synaptically evoked plateau potentials in dLGN cells is needed for remodeling by using a mutant mouse that lacks the ancillary β3 subunit and, as a consequence, has highly reduced L-type channel expression and attenuated L-type Ca(2+) currents. In the dLGNs of β3-null mice, glutamatergic postsynaptic activity evoked by optic tract stimulation was normal, but plateau potentials were rarely observed. The few plateaus that were evoked required high rates of retinal stimulation, but were still greatly attenuated compared with those recorded in age-matched wild-type mice. While β3-null mice exhibit normal stage II and III retinal waves, their retinogeniculate projections fail to segregate properly and dLGN cells show a high degree of retinal convergence even at late postnatal ages. These structural and functional defects were also accompanied by a reduction in CREB phosphorylation, a signaling event that has been shown to be essential for retinogeniculate axon segregation. Thus, postsynaptic L-type Ca(2+) activity plays an important role in mediating the refinement of the retinogeniculate pathway.
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145
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Bedogni F, Cobolli Gigli C, Pozzi D, Rossi RL, Scaramuzza L, Rossetti G, Pagani M, Kilstrup-Nielsen C, Matteoli M, Landsberger N. Defects During Mecp2 Null Embryonic Cortex Development Precede the Onset of Overt Neurological Symptoms. Cereb Cortex 2015; 26:2517-2529. [PMID: 25979088 DOI: 10.1093/cercor/bhv078] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
MeCP2 is associated with several neurological disorders; of which, Rett syndrome undoubtedly represents the most frequent. Its molecular roles, however, are still unclear, and data from animal models often describe adult, symptomatic stages, while MeCP2 functions during embryonic development remain elusive. We describe the pattern and timing of Mecp2 expression in the embryonic neocortex highlighting its low but consistent expression in virtually all cells and show the unexpected occurrence of transcriptional defects in the Mecp2 null samples at a stage largely preceding the onset of overt symptoms. Through the deregulated expression of ionic channels and glutamatergic receptors, the lack of Mecp2 during early neuronal maturation leads to the reduction in the neuronal responsiveness to stimuli. We suggest that such features concur to morphological alterations that begin affecting Mecp2 null neurons around the perinatal age and become evident later in adulthood. We indicate MeCP2 as a key modulator of the transcriptional mechanisms regulating cerebral cortex development. Neurological phenotypes of MECP2 patients could thus be the cumulative result of different adverse events that are already present at stages when no obvious signs of the pathology are evident and are worsened by later impairments affecting the central nervous system during maturation and maintenance of its functionality.
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Affiliation(s)
- Francesco Bedogni
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Clementina Cobolli Gigli
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.,Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
| | - Davide Pozzi
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Rozzano, 20089 Milan, Italy
| | - Riccardo Lorenzo Rossi
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Linda Scaramuzza
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy
| | - Grazisa Rossetti
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Massimiliano Pagani
- Istituto Nazionale di Genetica Molecolare "Romeo ed Enrica Invernizzi", 20122 Milan, Italy
| | - Charlotte Kilstrup-Nielsen
- Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
| | - Michela Matteoli
- Laboratory of Pharmacology and Brain Pathology, Humanitas Clinical and Research Center, Rozzano, 20089 Milan, Italy.,Dip di Biotecnologie Mediche e Medicina Traslazionale, Università di Milano, Milan, Italy
| | - Nicoletta Landsberger
- San Raffaele Rett Research Unit, Division of Neuroscience, San Raffaele Scientific Institute, 20132 Milan, Italy.,Laboratory of Genetic and Epigenetic Control of Gene Expression, Division of Biomedical Research, Department of Theoretical and Applied Sciences, University of Insubria, Busto Arsizio, 21052 Varese, Italy
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146
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Smalheiser NR. The RNA-centred view of the synapse: non-coding RNAs and synaptic plasticity. Philos Trans R Soc Lond B Biol Sci 2015; 369:rstb.2013.0504. [PMID: 25135965 PMCID: PMC4142025 DOI: 10.1098/rstb.2013.0504] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
If mRNAs were the only RNAs made by a neuron, there would be a simple mapping of mRNAs to proteins. However, microRNAs and other non-coding RNAs (ncRNAs; endo-siRNAs, piRNAs, BC1, BC200, antisense and long ncRNAs, repeat-related transcripts, etc.) regulate mRNAs via effects on protein translation as well as transcriptional and epigenetic mechanisms. Not only are genes ON or OFF, but their ability to be translated can be turned ON or OFF at the level of synapses, supporting an enormous increase in information capacity. Here, I review evidence that ncRNAs are expressed pervasively within dendrites in mammalian brain; that some are activity-dependent and highly enriched near synapses; and that synaptic ncRNAs participate in plasticity responses including learning and memory. Ultimately, ncRNAs can be viewed as the post-it notes of the neuron. They have no literal meaning of their own, but derive their functions from where (and to what) they are stuck. This may explain, in part, why ncRNAs differ so dramatically from protein-coding genes, both in terms of the usual indicators of functionality and in terms of evolutionary constraints. ncRNAs do not appear to be direct mediators of synaptic transmission in the manner of neurotransmitters or receptors, yet they orchestrate synaptic plasticity—and may drive species-specific changes in cognition.
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Affiliation(s)
- Neil R Smalheiser
- Department of Psychiatry, University of Illinois at Chicago, Chicago, IL 60612, USA
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147
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Yong SM, Ong QR, Siew BE, Wong BS. The effect of chicken extract on ERK/CREB signaling is ApoE isoform-dependent. Food Funct 2015; 5:2043-51. [PMID: 25080220 DOI: 10.1039/c4fo00428k] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
It is unclear how the nutritional supplement chicken extract (CE) enhances cognition. Human apolipoprotein E (ApoE) can regulate cognition and this isoform-dependent effect is associated with the N-methyl-d-aspartate receptor (NMDAR). To understand if CE utilizes this pathway, we compared the NMDAR signaling in neuronal cells expressing ApoE3 and ApoE4. We observed that CE increased S896 phosphorylation on NR1 in ApoE3 cells and this was linked to higher protein kinase C (PKC) activation. However, ApoE4 cells treated with CE have lowered S897 phosphorylation on NR1 and this was associated with reduced protein kinase A (PKA) phosphorylation. In ApoE3 cells, CE increased calmodulin kinase II (CaMKII) activation and AMPA GluR1 phosphorylation on S831. In contrast, CE reduced CaMKII phosphorylation and led to higher de-phosphorylation of S831 and S845 on GluR1 in ApoE4 cells. While CE enhanced ERK/CREB phosphorylation in ApoE3 cells, this pathway was down-regulated in both ApoE4 and mock cells after CE treatment. These results show that CE triggers ApoE isoform-specific changes on ERK/CREB signaling.
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Affiliation(s)
- Shan-May Yong
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, 2 Medical Drive MD9, Singapore 117597.
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148
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Dendritic geometry shapes neuronal cAMP signalling to the nucleus. Nat Commun 2015; 6:6319. [PMID: 25692798 PMCID: PMC4346624 DOI: 10.1038/ncomms7319] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 01/16/2015] [Indexed: 12/12/2022] Open
Abstract
Neurons have complex dendritic trees, receiving numerous inputs at various distances from the cell body. Yet the rules of molecular signal propagation from dendrites to nuclei are unknown. DARPP-32 is a phosphorylation-regulated signalling hub in striatal output neurons. We combine diffusion-reaction modelling and live imaging to investigate cAMP-activated DARPP-32 signalling to the nucleus. The model predicts maximal effects on the nucleus of cAMP production in secondary dendrites, due to segmental decrease of dendrite diameter. Variations in branching, perikaryon size or spines have less pronounced effects. Biosensor kinase activity measurement following cAMP or dopamine uncaging confirms these predictions. Histone 3 phosphorylation, regulated by this pathway, is best stimulated by cAMP released in secondary-like dendrites. Thus, unexpectedly, the efficacy of diffusion-based signalling from dendrites to nucleus is not inversely proportional to the distance. We suggest a general mechanism by which dendritic geometry counterbalances the effect of dendritic distance for signalling to the nucleus.
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149
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Wallace R. Poised for survival: criticality, natural selection, and excitation-transcription coupling. Int J Biochem Cell Biol 2015; 61:1-7. [PMID: 25622558 DOI: 10.1016/j.biocel.2015.01.013] [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: 06/06/2014] [Revised: 12/16/2014] [Accepted: 01/16/2015] [Indexed: 11/27/2022]
Abstract
Neurologically-complex species utilize two intricately coupled information-processing systems to adapt to their social and natural environments. Action potentials (APs) facilitate rapid responses to the nearly continuous fluctuations in the animal's surroundings. By contrast, genetic encodings comprise a molecular memory of ancient adaptive responses expressed as cognitive, emotional, or behavioral phenotypes. The linking of the two systems via intracellular Ca(2+) networks which address transcription factors - e.g., cAMP response element-binding protein (CREB) - is an appropriate focus for the biology of human behavior. Computational modeling utilizing Boolean networks (BNs) is a suitable qualitative method, requiring no kinetic information, for eliciting the systems' architectural properties. In particular, BNs can reveal critical intracellular regimes of possible evolutionary significance. As a platform for future research, we propose that those networks sufficiently robust to attenuate damaging intracellular noise and deleterious mutations, yet sufficiently close to chaos to permit or amplify adaptive noise and favorable mutations, would be favored by natural selection. Critical regimes of this type would be, literally, "poised for survival", and would stabilize and promote the survival of their correlated cultural phenotypes.
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Affiliation(s)
- Ron Wallace
- Department of Anthropology, University of Central Florida, PO Box 25000, Orlando, FL 32816 USA.
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150
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Sui WH, Huang SH, Wang J, Chen Q, Liu T, Chen ZY. Myosin Va mediates BDNF-induced postendocytic recycling of full-length TrkB and its translocation into dendritic spines. J Cell Sci 2015; 128:1108-22. [PMID: 25632160 DOI: 10.1242/jcs.160259] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays an important role in neuronal survival, neurite outgrowth and synaptic plasticity by activating the receptor tropomyosin receptor kinase B (TrkB, also known as NTRK2). TrkB has been shown to undergo recycling after BDNF stimulation. We have previously reported that full-length TrkB (TrkB-FL) are recycled through a Rab11-dependent pathway upon BDNF stimuli, which is important for the translocation of TrkB-FL into dendritic spines and for the maintenance of prolonged BDNF downstream signaling during long-term potentiation (LTP). However, the identity of the motor protein that mediates the local transfer of recycled TrkB-FL back to the plasma membrane remains unclear. Here, we report that the F-actin-based motor protein myosin Va (Myo5a) mediates the postendocytic recycling of TrkB-FL. Blocking the interaction between Rab11 and Myo5a by use of a TAT-tagged peptide consisting of amino acids 55-66 of the Myo5a ExonE domain weakened the association between TrkB-FL and Myo5a and thus impaired TrkB-FL recycling and BDNF-induced TrkB-FL translocation into dendritic spines. Finally, inhibiting Myo5a-mediated TrkB-FL recycling led to a significant reduction in prolonged BDNF downstream signaling. Taken together, these results show that Myo5a mediates BDNF-dependent TrkB-FL recycling and contributes to BDNF-induced TrkB spine translocation and prolonged downstream signaling.
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Affiliation(s)
- Wen-Hai Sui
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Shu-Hong Huang
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Jue Wang
- Central Research Laboratory, The Second Hospital of Shandong University, No.247 Beiyuan Dajie, Jinan, Shandong 250033, P.R. China
| | - Qun Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Ting Liu
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
| | - Zhe-Yu Chen
- Department of Neurobiology, Shandong Provincial Key Laboratory of Mental Disorders, CAS Center for Excellence in Brain Science, School of Medicine, Shandong University, No.44 Wenhua Xi Road, Jinan, Shandong 250012, P.R. China
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