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Aggarwal A, Yadav B, Sharma N, Kaur R, Rishi V. Disruption of histone acetylation homeostasis triggers cognitive dysfunction in experimental diabetes. Neurochem Int 2023; 170:105592. [PMID: 37598859 DOI: 10.1016/j.neuint.2023.105592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 08/10/2023] [Accepted: 08/16/2023] [Indexed: 08/22/2023]
Abstract
Epigenetic mechanisms related to diabetes-afflicted CNS complications are largely unknown. The present study investigated the role of histone acetylation mechanisms triggering cognitive dysfunction in the Type 1 and 2 diabetic mice model. Dynamic changes in diabetic parameters like fasting blood glucose levels, glucose tolerance test, and insulin levels were observed after the induction of diabetes. Cognitive performance was significantly diminished in T1D and T2D mice examined by the Morris water maze, novel object recognition test, and Y Maze as compared to controls. Histone profiling revealed a significant reduction in H3K9/14 and H4K12 acetylation in the cortex and hippocampus of T1D and T2D mice vs Controls. While histone deacetylase (HDAC) activity was significantly elevated in brain regions of T1D and T2D mice, the histone acetyltransferase (HAT) activity remain unchanged. Significantly increased HDAC 2, HDAC 3 protein and mRNA expression observed in T1D and T2D brain regions may corroborate for increased HDAC activity. No significant change was observed in protein and mRNA expression of HDAC 1, 5, 6, and 7 in diabetic brains. Reduced H3K9/14 and H4K12 acetylation paralleled transcriptional repression of memory-related markers BDNF, SYP, and PSD-95 in the cortex and hippocampus of T1D and T2D. Pharmacological inhibition of HDAC activity by Trichostatin A enhanced the cognitive changes observed in T1D and T2D by ameliorating BDNF, SYP, Psd-95. The present study provides a better insight into molecular mechanisms related to diabetes-dependent memory changes that can help to generate new advances for therapeutics to be developed in this area.
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Affiliation(s)
- Aanchal Aggarwal
- National Agri-Food Biotechnology Institute, Knowledge City, Sector-81, SAS Nagar, Punjab, India.
| | - Binduma Yadav
- National Agri-Food Biotechnology Institute, Knowledge City, Sector-81, SAS Nagar, Punjab, India; Regional Centre for Biotechnology (RCB), NCR Biotech Science Cluster, Faridabad, Haryana, India
| | - Nishtha Sharma
- National Agri-Food Biotechnology Institute, Knowledge City, Sector-81, SAS Nagar, Punjab, India
| | - Raminder Kaur
- National Agri-Food Biotechnology Institute, Knowledge City, Sector-81, SAS Nagar, Punjab, India; Department of Biotechnology, Sector-25, BMS Block I, Panjab University, Chandigarh, India
| | - Vikas Rishi
- National Agri-Food Biotechnology Institute, Knowledge City, Sector-81, SAS Nagar, Punjab, India.
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2
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Damiani F, Cornuti S, Tognini P. The gut-brain connection: Exploring the influence of the gut microbiota on neuroplasticity and neurodevelopmental disorders. Neuropharmacology 2023; 231:109491. [PMID: 36924923 DOI: 10.1016/j.neuropharm.2023.109491] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/22/2023] [Accepted: 03/05/2023] [Indexed: 03/17/2023]
Abstract
Neuroplasticity refers to the ability of brain circuits to reorganize and change the properties of the network, resulting in alterations in brain function and behavior. It is traditionally believed that neuroplasticity is influenced by external stimuli, learning, and experience. Intriguingly, there is new evidence suggesting that endogenous signals from the body's periphery may play a role. The gut microbiota, a diverse community of microorganisms living in harmony with their host, may be able to influence plasticity through its modulation of the gut-brain axis. Interestingly, the maturation of the gut microbiota coincides with critical periods of neurodevelopment, during which neural circuits are highly plastic and potentially vulnerable. As such, dysbiosis (an imbalance in the gut microbiota composition) during early life may contribute to the disruption of normal developmental trajectories, leading to neurodevelopmental disorders. This review aims to examine the ways in which the gut microbiota can affect neuroplasticity. It will also discuss recent research linking gastrointestinal issues and bacterial dysbiosis to various neurodevelopmental disorders and their potential impact on neurological outcomes.
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Affiliation(s)
| | - Sara Cornuti
- Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy
| | - Paola Tognini
- Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy; Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
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3
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Schiapparelli LM, Xie Y, Sharma P, McClatchy DB, Ma Y, Yates JR, Maximov A, Cline HT. Activity-Induced Cortical Glutamatergic Neuron Nascent Proteins. J Neurosci 2022; 42:7900-7920. [PMID: 36261270 PMCID: PMC9617616 DOI: 10.1523/jneurosci.0707-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 08/26/2022] [Accepted: 08/30/2022] [Indexed: 11/21/2022] Open
Abstract
Neuronal activity initiates signaling cascades that culminate in diverse outcomes including structural and functional neuronal plasticity, and metabolic changes. While studies have revealed activity-dependent neuronal cell type-specific transcriptional changes, unbiased quantitative analysis of cell-specific activity-induced dynamics in newly synthesized proteins (NSPs) synthesis in vivo has been complicated by cellular heterogeneity and a relatively low abundance of NSPs within the proteome in the brain. Here we combined targeted expression of mutant MetRS (methionine tRNA synthetase) in genetically defined cortical glutamatergic neurons with tight temporal control of treatment with the noncanonical amino acid, azidonorleucine, to biotinylate NSPs within a short period after pharmacologically induced seizure in male and female mice. By purifying peptides tagged with heavy or light biotin-alkynes and using direct tandem mass spectrometry detection of biotinylated peptides, we quantified activity-induced changes in cortical glutamatergic neuron NSPs. Seizure triggered significant changes in ∼300 NSPs, 33% of which were decreased by seizure. Proteins mediating excitatory and inhibitory synaptic plasticity, including SynGAP1, Pak3, GEPH1, Copine-6, and collybistin, and DNA and chromatin remodeling proteins, including Rad21, Smarca2, and Ddb1, are differentially synthesized in response to activity. Proteins likely to play homeostatic roles in response to activity, such as regulators of proteastasis, intracellular ion control, and cytoskeleton remodeling proteins, are activity induced. Conversely, seizure decreased newly synthetized NCAM, among others, suggesting that seizure induced degradation. Overall, we identified quantitative changes in the activity-induced nascent proteome from genetically defined cortical glutamatergic neurons as a strategy to discover downstream mediators of neuronal plasticity and generate hypotheses regarding their function.SIGNIFICANCE STATEMENT Activity-induced neuronal and synaptic plasticity are mediated by changes in the protein landscape, including changes in the activity-induced newly synthesized proteins; however, identifying neuronal cell type-specific nascent proteome dynamics in the intact brain has been technically challenging. We conducted an unbiased proteomic screen from which we identified significant activity-induced changes in ∼300 newly synthesized proteins in genetically defined cortical glutamatergic neurons within 20 h after pharmacologically induced seizure. Bioinformatic analysis of the dynamic nascent proteome indicates that the newly synthesized proteins play diverse roles in excitatory and inhibitory synaptic plasticity, chromatin remodeling, homeostatic mechanisms, and proteasomal and metabolic functions, extending our understanding of the diversity of plasticity mechanisms.
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Affiliation(s)
- Lucio M Schiapparelli
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
| | - Yi Xie
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
- Skaggs Graduate School, Scripps Research Institute, La Jolla, California 92037
| | - Pranav Sharma
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
- Xosomix, San Diego, California 92121
| | - Daniel B McClatchy
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - Yuanhui Ma
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - John R Yates
- Department of Molecular Medicine, Scripps Research Institute, La Jolla, California 92037
| | - Anton Maximov
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
| | - Hollis T Cline
- Neuroscience Department and Dorris Neuroscience Center, Scripps Research Institute, La Jolla, California 92037
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4
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The Role of DNA Methylation in Stroke Recovery. Int J Mol Sci 2022; 23:ijms231810373. [PMID: 36142283 PMCID: PMC9499691 DOI: 10.3390/ijms231810373] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 11/17/2022] Open
Abstract
Epigenetic alterations affect the onset of ischemic stroke, brain injury after stroke, and mechanisms of poststroke recovery. In particular, DNA methylation can be dynamically altered by maintaining normal brain function or inducing abnormal brain damage. DNA methylation is regulated by DNA methyltransferase (DNMT), which promotes methylation, DNA demethylase, which removes methyl groups, and methyl-cytosine–phosphate–guanine-binding domain (MBD) protein, which binds methylated DNA and inhibits gene expression. Investigating the effects of modulating DNMT, TET, and MBD protein expression on neuronal cell death and neurorepair in ischemic stroke and elucidating the underlying mechanisms can facilitate the formulation of therapeutic strategies for neuroprotection and promotion of neuronal recovery after stroke. In this review, we summarize the role of DNA methylation in neuroprotection and neuronal recovery after stroke according to the current knowledge regarding the effects of DNA methylation on excitotoxicity, oxidative stress, apoptosis, neuroinflammation, and recovery after ischemic stroke. This review of the literature regarding the role of DNA methylation in neuroprotection and functional recovery after stroke may contribute to the development and application of novel therapeutic strategies for stroke.
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Yang L, Hao JR, Gao Y, Yang X, Shen XR, Wang HY, Sun N, Gao C. HDAC3 of dorsal hippocampus induces postoperative cognitive dysfunction in aged mice. Behav Brain Res 2022; 433:114002. [PMID: 35810999 DOI: 10.1016/j.bbr.2022.114002] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 06/16/2022] [Accepted: 07/05/2022] [Indexed: 12/18/2022]
Abstract
Postoperative cognitive dysfunction (POCD) affects a substantial number of aged individuals. Although advanced age has been regarded as the only independent risk factor for cognitive decline following anesthesia and surgery, the exact cellular and molecular mechanisms remain poorly understood. Histone deacetylase 3 (HDAC3), an epigenetic regulator of memory plays an important role in age-dependent disease. In this study, we investigated the role of HDAC3 in POCD using a laparotomy mouse model. The results showed that the level of HDAC3 in the dorsal hippocampus (DH) was elevated in aged mice compared with young mice. The surgery impaired the spatial-temporal memory in aged mice, as indicated in the object location memory (OLM) and temporal order memory (TOM) tests. Model mice also exhibited increased expression of HDAC3 protein and decreased levels of dendritic spine density and synaptic plasticity-related proteins in the DH. Selectively blocking HDAC3 in the DH of aged mice reversed spatial-temporal memory impairment induced by surgery and restored dendritic spine density and synaptic plasticity-related proteins in the DH. Overexpression of HDAC3 by adeno-associated virus in the DH of young mice mimicked the behavioral deficits induced by anesthesia and surgery. Our results indicated that HDAC3 negatively regulates spatial-temporal memory in aged mice after anesthesia and surgery. Targeting HDAC3 might represent a potential therapy to avoid POCD.
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Affiliation(s)
- Li Yang
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China; The Affiliated Xuzhou Municipal Hospital of Xuzhou Medical University, Xuzhou, Jiangsu 221002, China.
| | - Jing-Ru Hao
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
| | - Yin Gao
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China; The Affiliated Nanjing Drum Tower Hospital of Xuzhou Medical University, Nanjing, Jiangsu 210008, China.
| | - Xiu Yang
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
| | - Xiao-Ran Shen
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
| | - Hu-Yi Wang
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
| | - Nan Sun
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
| | - Can Gao
- NMPA Key Laboratory for Research and Evaluation of Narcotic and Psychotropic Drugs, Jiangsu Province Key Laboratory of Anesthesiology, Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, 221004 Xuzhou, Jiangsu, China.
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6
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Peltz G, Tan Y. What Have We Learned (or Expect to) From Analysis of Murine Genetic Models Related to Substance Use Disorders? Front Psychiatry 2022; 12:793961. [PMID: 35095607 PMCID: PMC8790171 DOI: 10.3389/fpsyt.2021.793961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 12/09/2021] [Indexed: 11/29/2022] Open
Abstract
The tremendous public health problem created by substance use disorders (SUDs) presents a major opportunity for mouse genetics. Inbred mouse strains exhibit substantial and heritable differences in their responses to drugs of abuse (DOA) and in many of the behaviors associated with susceptibility to SUD. Therefore, genetic discoveries emerging from analysis of murine genetic models can provide critically needed insight into the neurobiological effects of DOA, and they can reveal how genetic factors affect susceptibility drug addiction. There are already indications, emerging from our prior analyses of murine genetic models of responses related to SUDs that mouse genetic models of SUD can provide actionable information, which can lead to new approaches for alleviating SUDs. Lastly, we consider the features of murine genetic models that enable causative genetic factors to be successfully identified; and the methodologies that facilitate genetic discovery.
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Affiliation(s)
- Gary Peltz
- Department of Anesthesia, Pain and Perioperative Medicine, Stanford University School of Medicine, Stanford, CA, United States
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7
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Yan Y, Tian M, Li M, Zhou G, Chen Q, Xu M, Hu Y, Luo W, Guo X, Zhang C, Xie H, Wu QF, Xiong W, Liu S, Guan JS. ASH1L haploinsufficiency results in autistic-like phenotypes in mice and links Eph receptor gene to autism spectrum disorder. Neuron 2022; 110:1156-1172.e9. [DOI: 10.1016/j.neuron.2021.12.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/23/2021] [Accepted: 12/27/2021] [Indexed: 12/12/2022]
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8
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Ji CH, Gu JH, Liu Y, Tang WQ, Guan W, Huang J, Chen YM, Xu DW, Jiang B. Hippocampal MSK1 regulates the behavioral and biological responses of mice to chronic social defeat stress: Involving of the BDNF-CREB signaling and neurogenesis. Biochem Pharmacol 2022; 195:114836. [PMID: 34774532 DOI: 10.1016/j.bcp.2021.114836] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 11/07/2021] [Accepted: 11/08/2021] [Indexed: 12/20/2022]
Abstract
Depression is one of the most common psychiatric diseases in the 21st century, while its pathogenesis is not yet fully understood. Currently, besides to the monoaminergic system, the brain-derived neurotrophic factor (BDNF)-cAMP response element-binding protein (CREB) signaling is one of the most attractive signaling pathways for treating depression. Mitogen and stress-activated kinase (MSK) 1 and 2 are nuclear proteins activated downstream of the ERK1/2 or p38 MAPK pathways, and it has been demonstrated that MSKs are involved in the BDNF-CREB signaling. Here we assumed that MSKs may play a role in depression, and various methods including the chronic social defeat stress (CSDS) model of depression, western blotting, immunofluorescence and virus-mediated gene transfer were used together. It was found that CSDS fully enhanced the expression of both phosphorylated MSK1 and total MSK1 in the hippocampus but not the medial prefrontal cortex (mPFC). CSDS did not influence the expression of phosphorylated MSK2 and total MSK2 in the two brain regions. Genetic over-expression of hippocampal MSK1 fully prevented not only the CSDS-induced depressive-like behaviors but also the CSDS-induced dysfunction in the hippocampal BDNF-CREB signaling and neurogenesis in mice, while genetic knockdown of hippocampal MSK1 aggravated the CSDS-induced depressive-like symptomatology in mice. Our results collectively suggest that although CSDS evidently enhances the activity of hippocampal MSK1, it is not a contributor to the CSDS-induced dysfunction in the brain but a defensive feedback regulator which protects against CSDS. Therefore, hippocampal MSK1 participates in the pathogenesis of depression and is a feasible and potential antidepressant target.
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Affiliation(s)
- Chun-Hui Ji
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Jiang-Hong Gu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Yue Liu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Wen-Qian Tang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Wei Guan
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Jie Huang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Yan-Mei Chen
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China
| | - Da-Wei Xu
- Department of Orthopaedics, Affiliated Hospital 2 of Nantong University, Nantong 226001, Jiangsu, China.
| | - Bo Jiang
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong 226001, Jiangsu, China.
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9
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Garay PM, Chen A, Tsukahara T, Rodríguez Díaz JC, Kohen R, Althaus JC, Wallner MA, Giger RJ, Jones KS, Sutton MA, Iwase S. RAI1 Regulates Activity-Dependent Nascent Transcription and Synaptic Scaling. Cell Rep 2021; 32:108002. [PMID: 32783930 PMCID: PMC7418709 DOI: 10.1016/j.celrep.2020.108002] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/17/2020] [Accepted: 07/15/2020] [Indexed: 12/15/2022] Open
Abstract
Long-lasting forms of synaptic plasticity such as synaptic scaling are critically dependent on transcription. Activity-dependent transcriptional dynamics in neurons, however, remain incompletely characterized because most previous efforts relied on measurement of steady-state mRNAs. Here, we use nascent RNA sequencing to profile transcriptional dynamics of primary neuron cultures undergoing network activity shifts. We find pervasive transcriptional changes, in which ∼45% of expressed genes respond to network activity shifts. We further link retinoic acid-induced 1 (RAI1), the Smith-Magenis syndrome gene, to the transcriptional program driven by reduced network activity. Remarkable agreement among nascent transcriptomes, dynamic chromatin occupancy of RAI1, and electrophysiological properties of Rai1-deficient neurons demonstrates the essential roles of RAI1 in suppressing synaptic upscaling in the naive network, while promoting upscaling triggered by activity silencing. These results highlight the utility of bona fide transcription profiling to discover mechanisms of activity-dependent chromatin remodeling that underlie normal and pathological synaptic plasticity. BrU-seq reveals nascent transcription during synaptic up- or downscaling Smith-Magenis syndrome protein RAI1 regulates upscaling-associated transcription RAI1 departs chromatin in response to network activity shifts RAI1 blocks upscaling in naive networks and promotes inactivity-induced upscaling
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Affiliation(s)
- Patricia M Garay
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Alex Chen
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Takao Tsukahara
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Rafi Kohen
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - J Christian Althaus
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Margarete A Wallner
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roman J Giger
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Cell and Developmental Biology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA; Cellular and Molecular Biology Graduate Program, University of Michigan Medical School, Ann Arbor, MI, 48109, USA; Department of Neurology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Kevin S Jones
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, 48109, USA
| | - Michael A Sutton
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Michigan Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Shigeki Iwase
- Neuroscience Graduate Program, University of Michigan Medical School, Ann Arbor, MI 48109, USA; Department of Human Genetics, University of Michigan, Ann Arbor, MI 48109, USA.
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Kumar A, Misra S, Nair P, Algahtany M. Epigenetics Mechanisms in Ischemic Stroke: A Promising Avenue? J Stroke Cerebrovasc Dis 2021; 30:105690. [PMID: 33684709 DOI: 10.1016/j.jstrokecerebrovasdis.2021.105690] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 12/27/2022] Open
Abstract
Stroke has emerged as the second most common cause of mortality worldwide and is a major public health problem. It is a multi-factorial disease and genetics plays an important role in its pathophysiology, however, mechanisms of genome involvement in the disease remain unclear. Both genetic and epigenetic mechanisms could play a role in the development of stroke disease. Although epigenetic characteristics may also be heritable, they can be modified during the lifetime under different environmental exposure in response to lifestyle. Recent studies provide clear evidence that epigenetic factors play an important role in the pathological mechanisms leading to an elevated risk of cardiovascular diseases and stroke. Epigenetic changes are reversible therefore; studying epigenetic factors may serve as a marker for disease progression, biomarker for disease diagnosis, and development of novel targets for therapeutic intervention. Identifying the factors which predispose the risk of stroke provides information for the mechanism of stroke and the design of new drug targets where epigenetic modifications play a significant role. Epigenetic modifications play an essential role in a large variety of multifactorial diseases. This review will focus on the evidence that epigenetic mechanisms play a crucial role in the pathophysiology of ischemic stroke.
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Affiliation(s)
- Amit Kumar
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
| | - Shubham Misra
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
| | - Pallavi Nair
- Department of Neurology, All India Institute of Medical Sciences, New Delhi, India.
| | - Mubarak Algahtany
- Division of Neurosurgery, Department of Surgery, College of Medicine, King Khalid University, Abha, Saudi Arabia.
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11
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Korai SA, Ranieri F, Di Lazzaro V, Papa M, Cirillo G. Neurobiological After-Effects of Low Intensity Transcranial Electric Stimulation of the Human Nervous System: From Basic Mechanisms to Metaplasticity. Front Neurol 2021; 12:587771. [PMID: 33658972 PMCID: PMC7917202 DOI: 10.3389/fneur.2021.587771] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 01/04/2021] [Indexed: 12/19/2022] Open
Abstract
Non-invasive low-intensity transcranial electrical stimulation (tES) of the brain is an evolving field that has brought remarkable attention in the past few decades for its ability to directly modulate specific brain functions. Neurobiological after-effects of tES seems to be related to changes in neuronal and synaptic excitability and plasticity, however mechanisms are still far from being elucidated. We aim to review recent results from in vitro and in vivo studies that highlight molecular and cellular mechanisms of transcranial direct (tDCS) and alternating (tACS) current stimulation. Changes in membrane potential and neural synchronization explain the ongoing and short-lasting effects of tES, while changes induced in existing proteins and new protein synthesis is required for long-lasting plastic changes (LTP/LTD). Glial cells, for decades supporting elements, are now considered constitutive part of the synapse and might contribute to the mechanisms of synaptic plasticity. This review brings into focus the neurobiological mechanisms and after-effects of tDCS and tACS from in vitro and in vivo studies, in both animals and humans, highlighting possible pathways for the development of targeted therapeutic applications.
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Affiliation(s)
- Sohaib Ali Korai
- Division of Human Anatomy - Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Federico Ranieri
- Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Vincenzo Di Lazzaro
- Neurology, Neurophysiology and Neurobiology Unit, University Campus Bio-Medico, Rome, Italy
| | - Michele Papa
- Division of Human Anatomy - Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", Naples, Italy.,ISBE Italy, SYSBIO Centre of Systems Biology, Milan, Italy
| | - Giovanni Cirillo
- Division of Human Anatomy - Laboratory of Neuronal Networks, University of Campania "Luigi Vanvitelli", Naples, Italy.,Neurology Unit, Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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12
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Mitf Links Neuronal Activity and Long-Term Homeostatic Intrinsic Plasticity. eNeuro 2020; 7:ENEURO.0412-19.2020. [PMID: 32193365 PMCID: PMC7174873 DOI: 10.1523/eneuro.0412-19.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/07/2020] [Accepted: 03/02/2020] [Indexed: 12/25/2022] Open
Abstract
Neuroplasticity forms the basis for neuronal circuit complexity and differences between otherwise similar circuits. We show that the microphthalmia-associated transcription factor (Mitf) plays a central role in intrinsic plasticity of olfactory bulb (OB) projection neurons. Mitral and tufted (M/T) neurons from Mitf mutant mice are hyperexcitable, have a reduced A-type potassium current (IA) and exhibit reduced expression of Kcnd3, which encodes a potassium voltage-gated channel subunit (Kv4.3) important for generating the IA Furthermore, expression of the Mitf and Kcnd3 genes is activity dependent in OB projection neurons and the MITF protein activates expression from Kcnd3 regulatory elements. Moreover, Mitf mutant mice have changes in olfactory habituation and have increased habituation for an odorant following long-term exposure, indicating that regulation of Kcnd3 is pivotal for long-term olfactory adaptation. Our findings show that Mitf acts as a direct regulator of intrinsic homeostatic feedback and links neuronal activity, transcriptional changes and neuronal function.
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13
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Wang T, Morency DT, Harris N, Davis GW. Epigenetic Signaling in Glia Controls Presynaptic Homeostatic Plasticity. Neuron 2019; 105:491-505.e3. [PMID: 31810838 DOI: 10.1016/j.neuron.2019.10.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 08/30/2019] [Accepted: 10/29/2019] [Indexed: 01/02/2023]
Abstract
Epigenetic gene regulation shapes neuronal fate in the embryonic nervous system. Post-embryonically, epigenetic signaling within neurons has been associated with impaired learning, autism, ataxia, and schizophrenia. Epigenetic factors are also enriched in glial cells. However, little is known about epigenetic signaling in glia and nothing is known about the intersection of glial epigenetic signaling and presynaptic homeostatic plasticity. During a screen for genes involved in presynaptic homeostatic synaptic plasticity, we identified an essential role for the histone acetyltransferase and deubiquitinase SAGA complex in peripheral glia. We present evidence that the SAGA complex is necessary for homeostatic plasticity, demonstrating involvement of four new genes in homeostatic plasticity. This is also evidence that glia participate in presynaptic homeostatic plasticity, invoking previously unexplored intercellular, homeostatic signaling at a tripartite synapse. We show, mechanistically, SAGA signaling regulates the composition of and signaling from the extracellular matrix during homeostatic plasticity.
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Affiliation(s)
- Tingting Wang
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA; Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Danielle T Morency
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
| | - Nathan Harris
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Graeme W Davis
- Department of Biochemistry and Biophysics, Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, San Francisco, CA 94158, USA.
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14
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Hilliard AT, Xie D, Ma Z, Snyder MP, Fernald RD. Genome-wide effects of social status on DNA methylation in the brain of a cichlid fish, Astatotilapia burtoni. BMC Genomics 2019; 20:699. [PMID: 31506062 PMCID: PMC6737626 DOI: 10.1186/s12864-019-6047-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 08/19/2019] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Successful social behavior requires real-time integration of information about the environment, internal physiology, and past experience. The molecular substrates of this integration are poorly understood, but likely modulate neural plasticity and gene regulation. In the cichlid fish species Astatotilapia burtoni, male social status can shift rapidly depending on the environment, causing fast behavioral modifications and a cascade of changes in gene transcription, the brain, and the reproductive system. These changes can be permanent but are also reversible, implying the involvement of a robust but flexible mechanism that regulates plasticity based on internal and external conditions. One candidate mechanism is DNA methylation, which has been linked to social behavior in many species, including A. burtoni. But, the extent of its effects after A. burtoni social change were previously unknown. RESULTS We performed the first genome-wide search for DNA methylation patterns associated with social status in the brains of male A. burtoni, identifying hundreds of Differentially Methylated genomic Regions (DMRs) in dominant versus non-dominant fish. Most DMRs were inside genes supporting neural development, synapse function, and other processes relevant to neural plasticity, and DMRs could affect gene expression in multiple ways. DMR genes were more likely to be transcription factors, have a duplicate elsewhere in the genome, have an anti-sense lncRNA, and have more splice variants than other genes. Dozens of genes had multiple DMRs that were often seemingly positioned to regulate specific splice variants. CONCLUSIONS Our results revealed genome-wide effects of A. burtoni social status on DNA methylation in the brain and strongly suggest a role for methylation in modulating plasticity across multiple biological levels. They also suggest many novel hypotheses to address in mechanistic follow-up studies, and will be a rich resource for identifying the relationships between behavioral, neural, and transcriptional plasticity in the context of social status.
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Affiliation(s)
| | - Dan Xie
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Zhihai Ma
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
| | - Michael P. Snyder
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305 USA
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15
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Abstract
In the past few decades, the field of neuroepigenetics has investigated how the brain encodes information to form long-lasting memories that lead to stable changes in behaviour. Activity-dependent molecular mechanisms, including, but not limited to, histone modification, DNA methylation and nucleosome remodelling, dynamically regulate the gene expression required for memory formation. Recently, the field has begun to examine how a learning experience is integrated at the level of both chromatin structure and synaptic physiology. Here, we provide an overview of key established epigenetic mechanisms that are important for memory formation. We explore how epigenetic mechanisms give rise to stable alterations in neuronal function by modifying synaptic structure and function, and highlight studies that demonstrate how manipulating epigenetic mechanisms may push the boundaries of memory.
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Affiliation(s)
- Rianne R Campbell
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Center for Addiction Neuroscience, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Marcelo A Wood
- Department of Neurobiology and Behavior, Center for the Neurobiology of Learning and Memory, Center for Addiction Neuroscience, Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA.
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16
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Lee MH, Siddoway B, Kaeser GE, Segota I, Rivera R, Romanow WJ, Liu CS, Park C, Kennedy G, Long T, Chun J. Somatic APP gene recombination in Alzheimer's disease and normal neurons. Nature 2018; 563:639-645. [PMID: 30464338 DOI: 10.1038/s41586-018-0718-6] [Citation(s) in RCA: 139] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 10/09/2018] [Indexed: 11/09/2022]
Abstract
The diversity and complexity of the human brain are widely assumed to be encoded within a constant genome. Somatic gene recombination, which changes germline DNA sequences to increase molecular diversity, could theoretically alter this code but has not been documented in the brain, to our knowledge. Here we describe recombination of the Alzheimer's disease-related gene APP, which encodes amyloid precursor protein, in human neurons, occurring mosaically as thousands of variant 'genomic cDNAs' (gencDNAs). gencDNAs lacked introns and ranged from full-length cDNA copies of expressed, brain-specific RNA splice variants to myriad smaller forms that contained intra-exonic junctions, insertions, deletions, and/or single nucleotide variations. DNA in situ hybridization identified gencDNAs within single neurons that were distinct from wild-type loci and absent from non-neuronal cells. Mechanistic studies supported neuronal 'retro-insertion' of RNA to produce gencDNAs; this process involved transcription, DNA breaks, reverse transcriptase activity, and age. Neurons from individuals with sporadic Alzheimer's disease showed increased gencDNA diversity, including eleven mutations known to be associated with familial Alzheimer's disease that were absent from healthy neurons. Neuronal gene recombination may allow 'recording' of neural activity for selective 'playback' of preferred gene variants whose expression bypasses splicing; this has implications for cellular diversity, learning and memory, plasticity, and diseases of the human brain.
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Affiliation(s)
- Ming-Hsiang Lee
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Benjamin Siddoway
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Gwendolyn E Kaeser
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Igor Segota
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Richard Rivera
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - William J Romanow
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Christine S Liu
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Chris Park
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.,Biomedical Sciences Program, School of Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Grace Kennedy
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Tao Long
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Jerold Chun
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
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17
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Langille JJ, Brown RE. The Synaptic Theory of Memory: A Historical Survey and Reconciliation of Recent Opposition. Front Syst Neurosci 2018; 12:52. [PMID: 30416432 PMCID: PMC6212519 DOI: 10.3389/fnsys.2018.00052] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 09/28/2018] [Indexed: 01/12/2023] Open
Abstract
Trettenbrein (2016) has argued that the concept of the synapse as the locus of memory is outdated and has made six critiques of this concept. In this article, we examine these six critiques and suggest that the current theories of the neurobiology of memory and the empirical data indicate that synaptic activation is the first step in a chain of cellular and biochemical events that lead to memories formed in cell assemblies and neural networks that rely on synaptic modification for their formation. These neural networks and their modified synaptic connections can account for the cognitive basis of learning and memory and for memory deterioration in neurological disorders. We first discuss Hebb's (1949) theory that synaptic change and the formation of cell assemblies and phase sequences can link neurophysiology to cognitive processes. We then examine each of Trettenbrein's (2016) critiques of the synaptic theory in light of Hebb's theories and recent empirical data. We examine the biochemical basis of memory formation and the necessity of synaptic modification to form the neural networks underlying learning and memory. We then examine the use of Hebb's theories of synaptic change and cell assemblies for integrating neurophysiological and cognitive conceptions of learning and memory. We conclude with an examination of the applications of the Hebb synapse and cell assembly theories to the study of the neuroscience of learning and memory, the development of computational models of memory and the construction of "intelligent" robots. We conclude that the synaptic theory of memory has not met its demise, but is essential to our understanding of the neural basis of memory, which has two components: synaptic plasticity and intrinsic plasticity.
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Affiliation(s)
| | - Richard E. Brown
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, NS, Canada
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18
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Long noncoding RNA GM12371 acts as a transcriptional regulator of synapse function. Proc Natl Acad Sci U S A 2018; 115:E10197-E10205. [PMID: 30297415 PMCID: PMC6205475 DOI: 10.1073/pnas.1722587115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Neuronal functions of long noncoding RNAs (lncRNAs) are poorly understood. Here we describe identification and function of lncRNA GM12371 in regulating synaptic transmission, synapse density, and dendritic arborization in primary hippocampal neurons. GM12371 expression is regulated by cAMP signaling and is critical for the activity regulated synaptic transmission. Importantly, GM12371 is associated with transcriptionally active chromatin and regulates expression of several genes involved in neuronal growth and development. Taken together, these results suggest that GM12371 acts as a transcriptional regulator of synapse function. Despite the growing evidence suggesting that long noncoding RNAs (lncRNAs) are critical regulators of several biological processes, their functions in the nervous system remain elusive. We have identified an lncRNA, GM12371, in hippocampal neurons that is enriched in the nucleus and necessary for synaptic communication, synapse density, synapse morphology, and dendritic tree complexity. Mechanistically, GM12371 regulates the expression of several genes involved in neuronal development and differentiation, as well as expression of specific lncRNAs and their cognate mRNA targets. Furthermore, we find that cAMP-PKA signaling up-regulates the expression of GM12371 and that its expression is essential for the activity-dependent changes in synaptic transmission in hippocampal neurons. Taken together, our data establish a key role for GM12371 in regulating synapse function.
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19
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Eagle AL, Williams ES, Beatty JA, Cox CL, Robison AJ. ΔFosB Decreases Excitability of Dorsal Hippocampal CA1 Neurons. eNeuro 2018; 5:ENEURO.0104-18.2018. [PMID: 30079375 PMCID: PMC6073980 DOI: 10.1523/eneuro.0104-18.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 07/06/2018] [Accepted: 07/13/2018] [Indexed: 02/03/2023] Open
Abstract
Both the function of hippocampal neurons and hippocampus-dependent behaviors are dependent on changes in gene expression, but the specific mechanisms that regulate gene expression in hippocampus are not yet fully understood. The stable, activity-dependent transcription factor ΔFosB plays a role in various forms of hippocampal-dependent learning and in the structural plasticity of synapses onto CA1 neurons. The authors examined the consequences of viral-mediated overexpression or inhibition of ΔFosB on the function of adult mouse hippocampal CA1 neurons using ex vivo slice whole-cell physiology. We found that the overexpression of ΔFosB decreased the excitability of CA1 pyramidal neurons, while inhibition increased excitability. Interestingly, these manipulations did not affect resting membrane potential or spike frequency adaptation, but ΔFosB overexpression reduced hyperpolarization-activated current. Both ΔFosB overexpression and inhibition decreased spontaneous excitatory postsynaptic currents, while only ΔFosB inhibition affected the AMPA/NMDA ratio, which was mediated by decreased NMDA receptor current, suggesting complex effects on synaptic inputs to CA1 that may be driven by homeostatic cell-autonomous or network-driven adaptations to the changes in CA1 cell excitability. Because ΔFosB is induced in hippocampus by drugs of abuse, stress, or antidepressant treatment, these results suggest that ΔFosB-driven changes in hippocampal cell excitability may be critical for learning and, in maladaptive states, are key drivers of aberrant hippocampal function in diseases such as addiction and depression.
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Affiliation(s)
- Andrew L Eagle
- Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Elizabeth S Williams
- Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Joseph A Beatty
- Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Charles L Cox
- Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
| | - Alfred J Robison
- Department of Physiology and Neuroscience Program, Michigan State University, East Lansing, Michigan 48824
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20
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Interplay between mitochondrial metabolism and oxidative stress in ischemic stroke: An epigenetic connection. Mol Cell Neurosci 2017; 82:176-194. [DOI: 10.1016/j.mcn.2017.05.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Revised: 04/26/2017] [Accepted: 05/24/2017] [Indexed: 12/18/2022] Open
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21
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Duke CG, Kennedy AJ, Gavin CF, Day JJ, Sweatt JD. Experience-dependent epigenomic reorganization in the hippocampus. ACTA ACUST UNITED AC 2017; 24:278-288. [PMID: 28620075 PMCID: PMC5473107 DOI: 10.1101/lm.045112.117] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/12/2017] [Indexed: 11/24/2022]
Abstract
Using a hippocampus-dependent contextual threat learning and memory task, we report widespread, coordinated DNA methylation changes in CA1 hippocampus of Sprague-Dawley rats specific to threat learning at genes involved in synaptic transmission. Experience-dependent alternations in gene expression and DNA methylation were observed as early as 1 h following memory acquisition and became more pronounced after 24 h. Gene ontology analysis revealed significant enrichment of functional categories related to synaptic transmission in genes that were hypomethylated at 24 h following threat learning. Integration of these data sets with previously characterized epigenetic and transcriptional changes in brain disease states suggested significant overlap between genes regulated by memory formation and genes altered in memory-related neurological and neuropsychiatric diseases. These findings provide a comprehensive resource to aid in the identification of memory-relevant therapeutic targets. Our results shed new light on the gene expression and DNA methylation changes involved in memory formation, confirming that these processes are dynamic and experience-dependent. Finally, this work provides a roadmap for future studies to identify linkage of memory-associated genes to altered disease states.
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Affiliation(s)
- Corey G Duke
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Andrew J Kennedy
- Department of Chemistry, Bates College, Lewiston, Maine 04240, USA
| | - Cristin F Gavin
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - Jeremy J Day
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
| | - J David Sweatt
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37235, USA
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22
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Fuchs JR, Darlington SW, Green JT, Morielli AD. Cerebellar learning modulates surface expression of a voltage-gated ion channel in cerebellar cortex. Neurobiol Learn Mem 2017; 142:252-262. [PMID: 28512010 DOI: 10.1016/j.nlm.2017.05.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/05/2017] [Accepted: 05/12/2017] [Indexed: 11/30/2022]
Abstract
Numerous experiments using ex vivo electrophysiology suggest that mammalian learning and memory involves regulation of voltage-gated ion channels in terms of changes in function. Yet, little is known about learning-related regulation of voltage-gated ion channels in terms of changes in expression. In two experiments, we examined changes in cell surface expression of the voltage-gated potassium channel alpha-subunit Kv1.2 in a discrete region of cerebellar cortex after eyeblink conditioning (EBC), a well-studied form of cerebellar-dependent learning. Kv1.2 in cerebellar cortex is expressed almost entirely in basket cells, primarily in the axon terminal pinceaux (PCX) region, and Purkinje cells, primarily in dendrites. Cell surface expression of Kv1.2 was measured using both multiphoton microscopy, which allowed measurement confined to the PCX region, and biotinylation/western blot, which measured total cell surface expression. In the first experiment, rats underwent three sessions of EBC, explicitly unpaired stimulus exposure, or context-only exposure and the results revealed a decrease in Kv1.2 cell surface expression in the unpaired group as measured with microscopy but no change as measured with western blot. In the second experiment, the same three training groups underwent only one half of a session of training, and the results revealed an increase in Kv1.2 cell surface expression in the unpaired group as measured with western blot but no change as measured with microscopy. In addition, rats in the EBC group that did not express conditioned responses (CRs) exhibited the same increase in Kv1.2 cell surface expression as the unpaired group. The overall pattern of results suggests that cell surface expression of Kv1.2 is changed with exposure to EBC stimuli in the absence, or prior to the emergence, of CRs.
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Affiliation(s)
- Jason R Fuchs
- Department of Psychological Science, University of Vermont, Burlington, VT 05405, United States
| | - Shelby W Darlington
- Department of Psychological Science, University of Vermont, Burlington, VT 05405, United States
| | - John T Green
- Department of Psychological Science, University of Vermont, Burlington, VT 05405, United States
| | - Anthony D Morielli
- Department of Pharmacology, University of Vermont, Burlington, VT 05405, United States.
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23
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Hunter CJ, Remenyi J, Correa SA, Privitera L, Reyskens KMSE, Martin KJ, Toth R, Frenguelli BG, Arthur JSC. MSK1 regulates transcriptional induction of Arc/Arg3.1 in response to neurotrophins. FEBS Open Bio 2017; 7:821-834. [PMID: 28593137 PMCID: PMC5458472 DOI: 10.1002/2211-5463.12232] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 03/23/2017] [Accepted: 03/31/2017] [Indexed: 12/29/2022] Open
Abstract
The immediate early gene activity‐regulated cytoskeletal protein (Arc)/Arg3.1 and the neurotrophin brain‐derived neurotrophic factor (BDNF) play important roles in synaptic plasticity and learning and memory in the mammalian brain. However, the mechanisms by which BDNF regulates the expression of Arc/Arg3.1 are unclear. In this study, we show that BDNF acts via the ERK1/2 pathway to activate the nuclear kinase mitogen‐ and stress‐activated protein kinase 1 (MSK1). MSK1 then induces Arc/Arg3.1 expression via the phosphorylation of histone H3 at the Arc/Arg3.1 promoter. MSK1 can also phosphorylate the transcription factor cyclic‐AMP response element‐binding protein (CREB) on Ser133. However, this is not required for BDNF‐induced Arc.Arg3.1 transcription as a Ser133Ala knockin mutation had no effect on Arc/Arg3.1 induction. In parallel, ERK1/2 directly activates Arc/Arg3.1 mRNA transcription via at least one serum response element on the promoter, which bind a complex of the Serum Response Factor (SRF) and a Ternary Complex Factor (TCF).
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Affiliation(s)
- Chris J Hunter
- MRC Protein Phosphorylation Unit College of Life Sciences Sir James Black Centre University of Dundee UK
| | - Judit Remenyi
- Wellcome Trust Centre for Gene Regulation and Expression Wellcome Trust Building College of Life Sciences University of Dundee UK
| | - Sonia A Correa
- Bradford School of Pharmacy Faculty of Life Sciences University of Bradford UK
| | | | - Kathleen M S E Reyskens
- Division of Cell Signalling and Immunology Wellcome Trust Building College of Life Sciences University of Dundee UK
| | - Kirsty J Martin
- MRC Protein Phosphorylation Unit College of Life Sciences Sir James Black Centre University of Dundee UK
| | - Rachel Toth
- MRC Protein Phosphorylation Unit College of Life Sciences Sir James Black Centre University of Dundee UK
| | | | - J Simon C Arthur
- Division of Cell Signalling and Immunology Wellcome Trust Building College of Life Sciences University of Dundee UK
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24
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Neuner SM, Wilmott LA, Hoffmann BR, Mozhui K, Kaczorowski CC. Hippocampal proteomics defines pathways associated with memory decline and resilience in normal aging and Alzheimer's disease mouse models. Behav Brain Res 2017; 322:288-298. [PMID: 27265785 PMCID: PMC5135662 DOI: 10.1016/j.bbr.2016.06.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Revised: 05/20/2016] [Accepted: 06/01/2016] [Indexed: 12/13/2022]
Abstract
Alzheimer's disease (AD), the most common form of dementia in the elderly, has no cure. Thus, the identification of key molecular mediators of cognitive decline in AD remains a top priority. As aging is the most significant risk factor for AD, the goal of this study was to identify altered proteins and pathways associated with the development of normal aging and AD memory deficits, and identify unique proteins and pathways that may contribute to AD-specific symptoms. We used contextual fear conditioning to diagnose 8-month-old 5XFAD and non-transgenic (Ntg) mice as having either intact or impaired memory, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify hippocampal membrane proteins across groups. Subsequent analysis detected 113 proteins differentially expressed relative to memory status (intact vs impaired) in Ntg mice and 103 proteins in 5XFAD mice. Thirty-six proteins, including several involved in neuronal excitability and synaptic plasticity (e.g., GRIA1, GRM3, and SYN1), were altered in both normal aging and AD. Pathway analysis highlighted HDAC4 as a regulator of observed protein changes in both genotypes and identified the REST epigenetic regulatory pathway and Gi intracellular signaling as AD-specific pathways involved in regulating the onset of memory deficits. Comparing the hippocampal membrane proteome of Ntg versus AD, regardless of cognitive status, identified 138 differentially expressed proteins, including confirmatory proteins APOE and CLU. Overall, we provide a novel list of putative targets and pathways with therapeutic potential, including a set of proteins associated with cognitive status in normal aging mice or gene mutations that cause AD.
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Affiliation(s)
- Sarah M Neuner
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Lynda A Wilmott
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Brian R Hoffmann
- Department of Medicine, Division of Cardiology and Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI, 53226 United States
| | - Khyobeni Mozhui
- Department of Preventive Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, United States
| | - Catherine C Kaczorowski
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN 38163, United States.
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25
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Biergans SD, Claudianos C, Reinhard J, Galizia CG. DNA methylation mediates neural processing after odor learning in the honeybee. Sci Rep 2017; 7:43635. [PMID: 28240742 PMCID: PMC5378914 DOI: 10.1038/srep43635] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 01/26/2017] [Indexed: 01/04/2023] Open
Abstract
DNA methyltransferases (Dnmts) - epigenetic writers catalyzing the transfer of methyl-groups to cytosine (DNA methylation) - regulate different aspects of memory formation in many animal species. In honeybees, Dnmt activity is required to adjust the specificity of olfactory reward memories and bees' relearning capability. The physiological relevance of Dnmt-mediated DNA methylation in neural networks, however, remains unknown. Here, we investigated how Dnmt activity impacts neuroplasticity in the bees' primary olfactory center, the antennal lobe (AL) an equivalent of the vertebrate olfactory bulb. The AL is crucial for odor discrimination, an indispensable process in forming specific odor memories. Using pharmacological inhibition, we demonstrate that Dnmt activity influences neural network properties during memory formation in vivo. We show that Dnmt activity promotes fast odor pattern separation in trained bees. Furthermore, Dnmt activity during memory formation increases both the number of responding glomeruli and the response magnitude to a novel odor. These data suggest that Dnmt activity is necessary for a form of homoeostatic network control which might involve inhibitory interneurons in the AL network.
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Affiliation(s)
- Stephanie D Biergans
- Queensland Brain Institute, The University of Queensland, Australia.,Neurobiologie, Universität Konstanz, Germany
| | - Charles Claudianos
- Queensland Brain Institute, The University of Queensland, Australia.,Monash Institute of Cognitive and Clinical Neuroscience, Faculty of Medicine, Nursing Health and Sciences, Monash University, Australia
| | - Judith Reinhard
- Queensland Brain Institute, The University of Queensland, Australia
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26
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The Kinase Function of MSK1 Regulates BDNF Signaling to CREB and Basal Synaptic Transmission, But Is Not Required for Hippocampal Long-Term Potentiation or Spatial Memory. eNeuro 2017; 4:eN-NWR-0212-16. [PMID: 28275711 PMCID: PMC5318545 DOI: 10.1523/eneuro.0212-16.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 12/26/2022] Open
Abstract
The later stages of long-term potentiation (LTP) in vitro and spatial memory in vivo are believed to depend upon gene transcription. Accordingly, considerable attempts have been made to identify both the mechanisms by which transcription is regulated and indeed the gene products themselves. Previous studies have shown that deletion of one regulator of transcription, the mitogen- and stress-activated kinase 1 (MSK1), causes an impairment of spatial memory. Given the ability of MSK1 to regulate gene expression via the phosphorylation of cAMP response element binding protein (CREB) at serine 133 (S133), MSK1 is a plausible candidate as a prime regulator of transcription underpinning synaptic plasticity and learning and memory. Indeed, prior work has revealed the necessity for MSK1 in homeostatic and experience-dependent synaptic plasticity. However, using a knock-in kinase-dead mouse mutant of MSK1, the current study demonstrates that, while the kinase function of MSK1 is important in regulating the phosphorylation of CREB at S133 and basal synaptic transmission in hippocampal area CA1, it is not required for metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD), two forms of LTP or several forms of spatial learning in the watermaze. These data indicate that other functions of MSK1, such as a structural role for the whole enzyme, may explain previous observations of a role for MSK1 in learning and memory.
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Vose LR, Stanton PK. Synaptic Plasticity, Metaplasticity and Depression. Curr Neuropharmacol 2017; 15:71-86. [PMID: 26830964 PMCID: PMC5327460 DOI: 10.2174/1570159x14666160202121111] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 08/13/2015] [Accepted: 01/30/2016] [Indexed: 01/30/2023] Open
Abstract
The development of a persistent depressive affective state has for some time been thought to result from persistent alterations in neurotransmitter-mediated synaptic transmission. While the identity of those transmitters has changed over the years, the literature has lacked mechanistic connections between the neurophysiological mechanisms they regulate, and how these mechanisms alter neuronal function, and, hence, affective homeostasis. This review will examine recent work that suggests that both long-term activity-dependent changes in synaptic strength (“plasticity”), and shifting set points for the ease of induction of future long-term changes (“metaplasticity”), may be critical to establishing and reversing a depressive behavioral state. Activity-dependent long-term synaptic plasticity involves both strengthening and weakening of synaptic connections associated with a dizzying array of neurochemical alterations that include synaptic insertion and removal of a number of subtypes of AMPA, NMDA and metabotropic glutamate receptors, changes in presynaptic glutamate release, and structural changes in dendritic spines. Cellular mechanisms of metaplasticity are far less well understood. Here, we will review the growing evidence that long-term synaptic changes in glutamatergic transmission, in brain regions that regulate mood, are key determinants of affective homeostasis and therapeutic targets with immense potential for drug development.
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Affiliation(s)
| | - Patric K Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY, 10595, USA
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Abstract
Epigenome editing aims for an introduction or removal of chromatin marks at a defined genomic region using artificial EpiEffectors resulting in a modulation of the activity of the targeted functional DNA elements. Rationally designed EpiEffectors consist of a targeting DNA-binding module (such as a zinc finger protein, TAL effector, or CRISPR/Cas complex) and usually, but not exclusively, a catalytic domain of a chromatin-modifying enzyme. Epigenome editing opens a completely new strategy for basic research of the central nervous system and causal treatment of psychiatric and neurological diseases, because rewriting of epigenetic information can lead to the direct and durable control of the expression of disease-associated genes. Here, we review current advances in the design of locus- and allele-specific DNA-binding modules, approaches for spatial, and temporal control of EpiEffectors and discuss some examples of existing and propose new potential therapeutic strategies based on epigenome editing for treatment of neurodegenerative and psychiatric diseases. These include the targeted silencing of disease-associated genes or activation of neuroprotective genes which may be applied in Alzheimer's and Parkinson's diseases or the control of addiction and depression. Moreover, we discuss allele-specific epigenome editing as novel therapeutic approach for imprinting disorders, Huntington's disease and Rett syndrome.
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Cirillo G, Di Pino G, Capone F, Ranieri F, Florio L, Todisco V, Tedeschi G, Funke K, Di Lazzaro V. Neurobiological after-effects of non-invasive brain stimulation. Brain Stimul 2017; 10:1-18. [DOI: 10.1016/j.brs.2016.11.009] [Citation(s) in RCA: 196] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 11/14/2016] [Accepted: 11/15/2016] [Indexed: 01/05/2023] Open
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Centeno TP, Shomroni O, Hennion M, Halder R, Vidal R, Rahman RU, Bonn S. Genome-wide chromatin and gene expression profiling during memory formation and maintenance in adult mice. Sci Data 2016; 3:160090. [PMID: 27727234 PMCID: PMC5058335 DOI: 10.1038/sdata.2016.90] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 08/30/2016] [Indexed: 01/04/2023] Open
Abstract
Recent evidence suggests that the formation and maintenance of memory requires epigenetic changes. In an effort to understand the spatio-temporal extent of learning and memory-related epigenetic changes we have charted genome-wide histone and DNA methylation profiles, in two different brain regions, two cell types, and three time-points, before and after learning. In this data descriptor we provide detailed information on data generation, give insights into the rationale of experiments, highlight necessary steps to assess data quality, offer guidelines for future use of the data and supply ready-to-use code to replicate the analysis results. The data provides a blueprint of the gene regulatory network underlying short- and long-term memory formation and maintenance. This 'healthy' gene regulatory network of learning can now be compared to changes in neurological or psychiatric diseases, providing mechanistic insights into brain disorders and highlighting potential therapeutic avenues.
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Affiliation(s)
- Tonatiuh Pena Centeno
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Orr Shomroni
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Magali Hennion
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Rashi Halder
- Research Group for Epigenetic Mechanisms in Dementia, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Ramon Vidal
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Raza-Ur Rahman
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
| | - Stefan Bonn
- Research Group for Computational Systems Biology, German Center for Neurodegenerative Diseases (DZNE), Von-Siebold-Straße 3A, 37075, Göttingen, Germany
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Klein HU, Bennett DA, De Jager PL. The epigenome in Alzheimer's disease: current state and approaches for a new path to gene discovery and understanding disease mechanism. Acta Neuropathol 2016; 132:503-14. [PMID: 27573688 DOI: 10.1007/s00401-016-1612-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 08/14/2016] [Accepted: 08/24/2016] [Indexed: 02/07/2023]
Abstract
The advent of new technologies and analytic approaches is beginning to provide an unprecedented look at features of the human genome that affect RNA expression. These "epigenomic" features are found in a number of different forms: they include DNA methylation, covalent modifications of histone proteins and non-coding RNAs. Some of these features have now been implicated in Alzheimer's disease (AD). Here, we focus on recent studies that have identified robust observations relating to DNA methylation and chromatin in human brain tissue; these findings will ground the next generation of studies and provide a model for the design of such studies. Stemming from observations that compounds with histone deacetylase activity may be beneficial in AD, epigenome-wide studies in cortical samples from large numbers of human subjects have now shown that AD-associated epigenomic changes are reproducible, are not driven by genetic risk factors, and are widespread at specific locations in the genome. A fundamental question of whether such changes are causal remains to be demonstrated, but it is already clear that well-powered investigations of the human epigenome in the target organ of a neurodegenerative disease are feasible, are implicating new areas of the genome in the disease, and will be an important tool for future studies. We are now at an inflection point: as genome-wide association studies of genetic variants come to an end, a new generation of studies exploring the epigenome will provide an important new layer of information with which to enrich our understanding of AD pathogenesis and to possibly guide development of new therapeutic targets.
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Affiliation(s)
- Hans-Ulrich Klein
- Program in Translational Neuropsychiatric Genomics and Partners Multiple Sclerosis Center, Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, 77 Avenue Louis Pasteur, NRB 168, Boston, MA, 02115, USA
- Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL, USA
| | - Philip L De Jager
- Program in Translational Neuropsychiatric Genomics and Partners Multiple Sclerosis Center, Department of Neurology, Ann Romney Center for Neurologic Diseases, Brigham and Women's Hospital, 77 Avenue Louis Pasteur, NRB 168, Boston, MA, 02115, USA.
- Harvard Medical School, Boston, MA, USA.
- Program in Medical and Population Genetics, Broad Institute, Cambridge, MA, USA.
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Meadows JP, Guzman-Karlsson MC, Phillips S, Brown JA, Strange SK, Sweatt JD, Hablitz JJ. Dynamic DNA methylation regulates neuronal intrinsic membrane excitability. Sci Signal 2016; 9:ra83. [PMID: 27555660 DOI: 10.1126/scisignal.aaf5642] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Epigenetic modifications, such as DNA cytosine methylation, contribute to the mechanisms underlying learning and memory by coordinating adaptive gene expression and neuronal plasticity. Transcription-dependent plasticity regulated by DNA methylation includes synaptic plasticity and homeostatic synaptic scaling. Memory-related plasticity also includes alterations in intrinsic membrane excitability mediated by changes in the abundance or activity of ion channels in the plasma membrane, which sets the threshold for action potential generation. We found that prolonged inhibition of DNA methyltransferase (DNMT) activity increased intrinsic membrane excitability of cultured cortical pyramidal neurons. Knockdown of the cytosine demethylase TET1 or inhibition of RNA polymerase blocked the increased membrane excitability caused by DNMT inhibition, suggesting that this effect was mediated by subsequent cytosine demethylation and de novo transcription. Prolonged DNMT inhibition blunted the medium component of the after-hyperpolarization potential, an effect that would increase neuronal excitability, and was associated with reduced expression of the genes encoding small-conductance Ca(2+)-activated K(+) (SK) channels. Furthermore, the specific SK channel blocker apamin increased neuronal excitability but was ineffective after DNMT inhibition. Our results suggested that DNMT inhibition enables transcriptional changes that culminate in decreased expression of SK channel-encoding genes and decreased activity of SK channels, thus providing a mechanism for the regulation of neuronal intrinsic membrane excitability by dynamic DNA cytosine methylation. This study has implications for human neurological and psychiatric diseases associated with dysregulated intrinsic excitability.
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Affiliation(s)
- Jarrod P Meadows
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mikael C Guzman-Karlsson
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Scott Phillips
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jordan A Brown
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Sarah K Strange
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - J David Sweatt
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA. Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John J Hablitz
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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Stress-induced bystander signaling as a possible factor contributing to neuronal excitability and seizure generation/epileptogenesis. Med Hypotheses 2016; 90:57-62. [DOI: 10.1016/j.mehy.2016.03.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 03/10/2016] [Indexed: 01/23/2023]
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Vaseghi B, Zoghi M, Jaberzadeh S. Unihemispheric concurrent dual-site cathodal transcranial direct current stimulation: the effects on corticospinal excitability. Eur J Neurosci 2016; 43:1161-72. [PMID: 26946332 DOI: 10.1111/ejn.13229] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 02/20/2016] [Accepted: 03/01/2016] [Indexed: 11/30/2022]
Abstract
We aimed to assess the effects of concurrent cathodal transcranial direct current stimulation (c-tDCS) of two targets in a hemisphere, termed unihemispheric concurrent dual-site cathodal tDCS (c-tDCSUHCDS ), on the size of M1 corticospinal excitability and its lasting effect. Secondary aims were to identify the mechanisms behind the efficacy of c-tDCSUHCDS and to evaluate the side effects of this new technique. Twelve healthy volunteers received 20 min c-tDCS under five conditions in a random order: M1 c-tDCS, c-tDCSUHCDS of M1-dorsolateral prefrontal cortex (DLPFC), M1-primary sensory cortex (S1), M1-primary visual cortex (V1) and sham. The M1 corticospinal excitability of the first dorsal interossei muscle was assessed before, immediately after, and 30 min, 60 min and 24 h after the interventions. Short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) were also assessed, using a paired-pulse paradigm. Compared to conventional M1 c-tDCS, corticospinal excitability significantly increased following c-tDCSUHCDS of M1-DLPFC and M1-V1 for up to 24 h (P = 0.001). Significant increases in ICF were observed following c-tDCSUHCDS of M1-DLPFC (P = 0.005) and M1-V1 (P = 0.002). Compared to baseline values, ICF and SICI increased significantly at T60 (P < 0.001) and T24 h (P < 0.001) following the concurrent c-tDCS of M1 and V1. Sham c-tDCSUHCDS did not induce any significant alteration. The corticospinal excitability increase was mainly accompanied by ICF increase, which indirectly indicates the activity of glutamergic mechanisms. The findings may help us to more fully understand the brain function and develop future motor learning studies. No significant excitability change induced by sham c-tDCSUHCDS suggests that there is no placebo effect associated with this new tDCS technique.
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Affiliation(s)
- Bita Vaseghi
- Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Building B, Frankston 3199, Melbourne, Vic., Australia
| | - Maryam Zoghi
- Department of Medicine, Royal Melbourne Hospital, The University of Melbourne, Melbourne, Vic., Australia
| | - Shapour Jaberzadeh
- Department of Physiotherapy, School of Primary Health Care, Faculty of Medicine, Nursing and Health Sciences, Monash University, Building B, Frankston 3199, Melbourne, Vic., Australia
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Expression of Quinone Reductase-2 in the Cortex Is a Muscarinic Acetylcholine Receptor-Dependent Memory Consolidation Constraint. J Neurosci 2016; 35:15568-81. [PMID: 26609153 DOI: 10.1523/jneurosci.1170-15.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
UNLABELLED Learning of novel information, including novel taste, requires activation of neuromodulatory transmission mediated, for example, by the muscarinic acetylcholine receptors (mAChRs) in relevant brain structures. In addition, drugs enhancing the function of mAChRs are used to treat memory impairment and decline. However, the mechanisms underlying these effects are poorly understood. Here, using quantitative RT-PCR in Wistar Hola rats, we found quinone reductase 2 (QR2) to be expressed in the cortex in an mAChR-dependent manner. QR2 mRNA expression in the insular cortex is inversely correlated with mAChR activation both endogenously, after novel taste learning, and exogenously, after pharmacological manipulation of the muscarinic transmission. Moreover, reducing QR2 expression levels through lentiviral shRNA vectors or activity via inhibitors is sufficient to enhance long-term memories. We also show here that, in patients with Alzheimer's disease, QR2 is overexpressed in the cortex. It is suggested that QR2 expression in the cortex is a removable limiting factor of memory formation and thus serves as a new target to enhance cognitive function and delay the onset of neurodegenerative diseases. SIGNIFICANCE STATEMENT We found that: (1) quinone reductase 2 (QR2) expression is a muscarinic-receptor-dependent removable constraint on memory formation in the cortex, (2) reducing QR2 expression or activity in the cortex enhances memory formation, and (3) Alzheimer's disease patients overexpressed QR2. We believe that these results propose a new mechanism by which muscarinic acetylcholine receptors affect cognition and suggest that inhibition of QR2 is a way to enhance cognition in normal and pathological conditions.
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Sweatt JD. Dynamic DNA methylation controls glutamate receptor trafficking and synaptic scaling. J Neurochem 2016; 137:312-30. [PMID: 26849493 DOI: 10.1111/jnc.13564] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 01/27/2016] [Accepted: 01/30/2016] [Indexed: 12/27/2022]
Abstract
Hebbian plasticity, including long-term potentiation and long-term depression, has long been regarded as important for local circuit refinement in the context of memory formation and stabilization. However, circuit development and stabilization additionally relies on non-Hebbian, homeostatic, forms of plasticity such as synaptic scaling. Synaptic scaling is induced by chronic increases or decreases in neuronal activity. Synaptic scaling is associated with cell-wide adjustments in postsynaptic receptor density, and can occur in a multiplicative manner resulting in preservation of relative synaptic strengths across the entire neuron's population of synapses. Both active DNA methylation and demethylation have been validated as crucial regulators of gene transcription during learning, and synaptic scaling is known to be transcriptionally dependent. However, it has been unclear whether homeostatic forms of plasticity such as synaptic scaling are regulated via epigenetic mechanisms. This review describes exciting recent work that has demonstrated a role for active changes in neuronal DNA methylation and demethylation as a controller of synaptic scaling and glutamate receptor trafficking. These findings bring together three major categories of memory-associated mechanisms that were previously largely considered separately: DNA methylation, homeostatic plasticity, and glutamate receptor trafficking. This review describes exciting recent work that has demonstrated a role for active changes in neuronal DNA methylation and demethylation as a controller of synaptic scaling and glutamate receptor trafficking. These findings bring together three major categories of memory-associated mechanisms that were previously considered separately: glutamate receptor trafficking, DNA methylation, and homeostatic plasticity.
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Affiliation(s)
- J David Sweatt
- Department of Neurobiology, Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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37
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Abstract
Over the past decade, since epigenetic mechanisms were first implicated in memory formation and synaptic plasticity, dynamic DNA methylation reactions have been identified as integral to long-term memory formation, maintenance, and recall. This review incorporates various new findings that DNA methylation mechanisms are important regulators of non-Hebbian plasticity mechanisms, suggesting that these epigenetic mechanisms are a fundamental link between synaptic plasticity and metaplasticity. Because the field of neuroepigenetics is so young and the biochemical tools necessary to probe gene-specific questions are just now being developed and used, this review also speculates about the direction and potential of therapeutics that target epigenetic mechanisms in the central nervous system and the unique pharmacokinetic and pharmacodynamic properties that epigenetic therapies may possess. Mapping the dynamics of the epigenome in response to experiential learning, even a single epigenetic mark in isolation, remains a significant technical and bioinformatic hurdle facing the field, but will be necessary to identify changes to the methylome that govern memory-associated gene expression and effectively drug the epigenome.
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Affiliation(s)
- Andrew J Kennedy
- a Department of Neurobiology , University of Alabama at Birmingham , Birmingham , AL , USA
| | - J David Sweatt
- a Department of Neurobiology , University of Alabama at Birmingham , Birmingham , AL , USA
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Quintero M, Olea E, Conde SV, Obeso A, Gallego-Martin T, Gonzalez C, Monserrat JM, Gómez-Niño A, Yubero S, Agapito T. Age protects from harmful effects produced by chronic intermittent hypoxia. J Physiol 2016; 594:1773-90. [PMID: 26752660 DOI: 10.1113/jp270878] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 01/06/2016] [Indexed: 12/23/2022] Open
Abstract
Obstructive sleep apnoea (OSA) affects an estimated 3–7% of the adult population, the frequency doubling at ages >60–65 years. As it evolves, OSA becomes frequently associated with cardiovascular, metabolic and neuropsychiatric pathologies defining OSA syndrome (OSAS). Exposing experimental animals to chronic intermittent hypoxia (CIH) can be used as a model of the recurrent hypoxic and O2 desaturation patterns observed in OSA patients. CIH is an important OSA event triggering associated pathologies; CIH induces carotid body (CB)-driven exaggerated sympathetic tone and overproduction of reactive oxygen species, related to the pathogenic mechanisms of associated pathologies observed in OSAS. Aiming to discover why OSAS is clinically less conspicuous in aged patients, the present study compares CIH effects in young (3–4 months) and aged (22–24 months) rats. To define potential distinctive patterns of these pathogenic mechanisms, mean arterial blood pressure as the final CIH outcome was measured. In young rats, CIH augmented CB sensory responses to hypoxia, decreased hypoxic ventilation and augmented sympathetic activity (plasma catecholamine levels and renal artery content and synthesis rate). An increased brainstem integration of CB sensory input as a trigger of sympathetic activity is suggested. CIH also caused an oxidative status decreasing aconitase/fumarase ratio and superoxide dismutase activity. In aged animals, CIH minimally affected CB responses, ventilation and sympathetic-related parameters leaving redox status unaltered. In young animals, CIH caused hypertension and in aged animals, whose baseline blood pressure was augmented, CIH did not augment it further. Plausible mechanisms of the differences and potential significance of these findings for the diagnosis and therapy of OSAS are discussed.
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Affiliation(s)
- M Quintero
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - E Olea
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - S V Conde
- Chronic Diseases Research Center (CEDOC), Nova Medical School, Faculdade de Ciências Médicas, University of Nova Lisboa, Lisbon, Portugal
| | - A Obeso
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - T Gallego-Martin
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - C Gonzalez
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - J M Monserrat
- Laboratori de la Son, Pneumologia, Hospital Clínic-IDIBAPS, Barcelona, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - A Gómez-Niño
- Department of Cell Biology, Histology and Pharmacology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - S Yubero
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
| | - T Agapito
- Department of Biochemistry and Molecular Biology and Physiology, School of Medicine, University of Valladolid and IBGM/CSIC, Valladolid, Spain.,CIBERES, Instituto de Salud Carlos III, Madrid, Spain
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Abstract
UNLABELLED The hippocampus (HPC) is known to play an important role in learning, a process dependent on synaptic plasticity; however, the molecular mechanisms underlying this are poorly understood. ΔFosB is a transcription factor that is induced throughout the brain by chronic exposure to drugs, stress, and variety of other stimuli and regulates synaptic plasticity and behavior in other brain regions, including the nucleus accumbens. We show here that ΔFosB is also induced in HPC CA1 and DG subfields by spatial learning and novel environmental exposure. The goal of the current study was to examine the role of ΔFosB in hippocampal-dependent learning and memory and the structural plasticity of HPC synapses. Using viral-mediated gene transfer to silence ΔFosB transcriptional activity by expressing ΔJunD (a negative modulator of ΔFosB transcriptional function) or to overexpress ΔFosB, we demonstrate that HPC ΔFosB regulates learning and memory. Specifically, ΔJunD expression in HPC impaired learning and memory on a battery of hippocampal-dependent tasks in mice. Similarly, general ΔFosB overexpression also impaired learning. ΔJunD expression in HPC did not affect anxiety or natural reward, but ΔFosB overexpression induced anxiogenic behaviors, suggesting that ΔFosB may mediate attentional gating in addition to learning. Finally, we found that overexpression of ΔFosB increases immature dendritic spines on CA1 pyramidal cells, whereas ΔJunD reduced the number of immature and mature spine types, indicating that ΔFosB may exert its behavioral effects through modulation of HPC synaptic function. Together, these results suggest collectively that ΔFosB plays a significant role in HPC cellular morphology and HPC-dependent learning and memory. SIGNIFICANCE STATEMENT Consolidation of our explicit memories occurs within the hippocampus, and it is in this brain region that the molecular and cellular processes of learning have been most closely studied. We know that connections between hippocampal neurons are formed, eliminated, enhanced, and weakened during learning, and we know that some stages of this process involve alterations in the transcription of specific genes. However, the specific transcription factors involved in this process are not fully understood. Here, we demonstrate that the transcription factor ΔFosB is induced in the hippocampus by learning, regulates the shape of hippocampal synapses, and is required for memory formation, opening up a host of new possibilities for hippocampal transcriptional regulation.
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Sanchez-Mut JV, Gräff J. Epigenetic Alterations in Alzheimer's Disease. Front Behav Neurosci 2015; 9:347. [PMID: 26734709 PMCID: PMC4681781 DOI: 10.3389/fnbeh.2015.00347] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 11/25/2015] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is the major cause of dementia in Western societies. It progresses asymptomatically during decades before being belatedly diagnosed when therapeutic strategies have become unviable. Although several genetic alterations have been associated with AD, the vast majority of AD cases do not show strong genetic underpinnings and are thus considered a consequence of non-genetic factors. Epigenetic mechanisms allow for the integration of long-lasting non-genetic inputs on specific genetic backgrounds, and recently, a growing number of epigenetic alterations in AD have been described. For instance, an accumulation of dysregulated epigenetic mechanisms in aging, the predominant risk factor of AD, might facilitate the onset of the disease. Likewise, mutations in several enzymes of the epigenetic machinery have been associated with neurodegenerative processes that are altered in AD such as impaired learning and memory formation. Genome-wide and locus-specific epigenetic alterations have also been reported, and several epigenetically dysregulated genes validated by independent groups. From these studies, a picture emerges of AD as being associated with DNA hypermethylation and histone deacetylation, suggesting a general repressed chromatin state and epigenetically reduced plasticity in AD. Here we review these recent findings and discuss several technical and methodological considerations that are imperative for their correct interpretation. We also pay particular focus on potential implementations and theoretical frameworks that we expect will help to better direct future studies aimed to unravel the epigenetic participation in AD.
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Affiliation(s)
- Jose V Sanchez-Mut
- Neuroepigenetics Laboratory - UPGRAEFF, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
| | - Johannes Gräff
- Neuroepigenetics Laboratory - UPGRAEFF, Brain Mind Institute, School of Life Sciences, École Polytechnique Fédérale de Lausanne Lausanne, Switzerland
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41
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DNA methylation changes in plasticity genes accompany the formation and maintenance of memory. Nat Neurosci 2015; 19:102-10. [PMID: 26656643 DOI: 10.1038/nn.4194] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 11/09/2015] [Indexed: 12/14/2022]
Abstract
The ability to form memories is a prerequisite for an organism's behavioral adaptation to environmental changes. At the molecular level, the acquisition and maintenance of memory requires changes in chromatin modifications. In an effort to unravel the epigenetic network underlying both short- and long-term memory, we examined chromatin modification changes in two distinct mouse brain regions, two cell types and three time points before and after contextual learning. We found that histone modifications predominantly changed during memory acquisition and correlated surprisingly little with changes in gene expression. Although long-lasting changes were almost exclusive to neurons, learning-related histone modification and DNA methylation changes also occurred in non-neuronal cell types, suggesting a functional role for non-neuronal cells in epigenetic learning. Finally, our data provide evidence for a molecular framework of memory acquisition and maintenance, wherein DNA methylation could alter the expression and splicing of genes involved in functional plasticity and synaptic wiring.
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42
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Zakhvataev VE. Possible scenarios of the influence of low-dose ionizing radiation on neural functioning. Med Hypotheses 2015; 85:723-35. [PMID: 26526727 DOI: 10.1016/j.mehy.2015.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 10/05/2015] [Accepted: 10/20/2015] [Indexed: 12/30/2022]
Abstract
Possible scenarios of the influence of ionizing radiation on neural functioning and the CNS are suggested. We argue that the radiation-induced bystander mechanisms associated with Ca(2+) flows, reactive nitrogen and oxygen species, and cytokines might lead to modulation of certain neuronal signaling pathways. The considered scenarios of conjugation of the bystander signaling and the neuronal signaling might result in modulation of certain synaptic receptors, neurogenesis, neurotransmission, channel conductance, synaptic signaling, different forms of neural plasticity, memory formation and storage, and learning. On this basis, corresponding new possible strategies for treating neurodegenerative deceases and mental disorders are proposed. The mechanisms considered might also be associated with neuronal survival and relevant to the treatment for brain injuries. At the same time, these mechanisms might be associated with detrimental effects and might facilitate the development of some neurological and psychiatric disorders.
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Affiliation(s)
- Vladimir E Zakhvataev
- Neuroinformatics Department, Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands; Laboratory of Biological Action of Low-Intensity Factors, Siberian Federal University, 79 Svobodny pr., 660041 Krasnoyarsk, Russia.
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43
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Abstract
Two recent papers center on the emerging intersection of DNA methylation and homeostatic plasticity. To better appreciate the context of these studies, we first briefly review the mechanistic connections between DNA methylation and plasticity before delving into the ways in which these two papers fortify the connection between synapse and nucleus but also highlight the need for studies with a broader perspective.
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Affiliation(s)
- Erin A Clark
- Department of Biology and Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA
| | - Sacha B Nelson
- Department of Biology and Center for Behavioral Genomics, Brandeis University, Waltham, MA 02454, USA.
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44
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Lopez-Atalaya JP, Valor LM, Barco A. Epigenetic factors in intellectual disability: the Rubinstein-Taybi syndrome as a paradigm of neurodevelopmental disorder with epigenetic origin. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 128:139-76. [PMID: 25410544 DOI: 10.1016/b978-0-12-800977-2.00006-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The number of genetic syndromes associated with intellectual disability that are caused by mutations in genes encoding chromatin-modifying enzymes has sharply risen in the last decade. We discuss here a neurodevelopmental disorder, the Rubinstein-Taybi syndrome (RSTS), originated by mutations in the genes encoding the lysine acetyltransferases CBP and p300. We first describe clinical and genetic aspects of the syndrome to later focus on the insight provided by the research in animal models of this disease. These studies have not only clarified the molecular etiology of RSTS and helped to dissect the developmental and adult components of the syndrome but also contributed to outline some important connections between epigenetics and cognition. We finally discuss how this body of research has opened new venues for the therapeutic intervention of this currently untreatable disease and present some of the outstanding questions in the field. We believe that the progress in the understanding of this rare disorder also has important implications for other intellectual disability disorders that share an epigenetic origin.
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Affiliation(s)
- Jose P Lopez-Atalaya
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Alicante, Spain
| | - Luis M Valor
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Alicante, Spain
| | - Angel Barco
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Alicante, Spain
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45
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Lister R, Mukamel EA. Turning over DNA methylation in the mind. Front Neurosci 2015; 9:252. [PMID: 26283895 PMCID: PMC4519686 DOI: 10.3389/fnins.2015.00252] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/06/2015] [Indexed: 01/22/2023] Open
Abstract
Cytosine DNA methylation is a stable epigenetic modification with established roles in regulating transcription, imprinting, female X-chromosome inactivation, and silencing of transposons. Dynamic gain or loss of DNA methylation reshapes the genomic landscape of cells during early differentiation, and in post-mitotic mammalian brain cells these changes continue to accumulate throughout the phases of cortical maturation in childhood and adolescence. There is also evidence for dynamic changes in the methylation status of specific genomic loci during the encoding of new memories, and these epigenome dynamics could play a causal role in memory formation. However, the mechanisms that may dynamically regulate DNA methylation in neurons during memory formation and expression, and the function of such epigenomic changes in this context, are unclear. Here we discuss the possible roles of DNA methylation in encoding and retrieval of memory.
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Affiliation(s)
- Ryan Lister
- ARC Center of Excellence in Plant Energy Biology, The University of Western Australia Perth, WA, Australia ; The Harry Perkins Institute of Medical Research Perth, WA, Australia
| | - Eran A Mukamel
- Department of Cognitive Science, University of California San Diego La Jolla, CA, USA
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46
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Morris MJ, Monteggia LM. Role of DNA methylation and the DNA methyltransferases in learning and memory. DIALOGUES IN CLINICAL NEUROSCIENCE 2015. [PMID: 25364286 PMCID: PMC4214178 DOI: 10.31887/dcns.2014.16.3/mmorris] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Dynamic regulation of chromatin structure in postmitotic neurons plays an important role in learning and memory. Methylation of cytosine nucleotides has historically been considered the strongest and least modifiable of epigenetic marks. Accumulating recent data suggest that rapid and dynamic methylation and demethylation of specific genes in the brain may play a fundamental role in learning, memory formation, and behavioral plasticity. The current review focuses on the emergence of data that support the role of DNA methylation and demethylation, and its molecular mediators in memory formation.
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Affiliation(s)
- Michael J Morris
- Department of Biological Sciences, University of Michigan-Dearborn, Dearborn, Michigan, USA
| | - Lisa M Monteggia
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas, USA
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47
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Meadows JP, Guzman-Karlsson MC, Phillips S, Holleman C, Posey JL, Day JJ, Hablitz JJ, Sweatt JD. DNA methylation regulates neuronal glutamatergic synaptic scaling. Sci Signal 2015; 8:ra61. [PMID: 26106219 DOI: 10.1126/scisignal.aab0715] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Enhanced receptiveness at all synapses on a neuron that receive glutamatergic input is called cell-wide synaptic upscaling. We hypothesize that this type of synaptic plasticity may be critical for long-term memory storage within cortical circuits, a process that may also depend on epigenetic mechanisms, such as covalent chemical modification of DNA. We found that DNA cytosine demethylation mediates multiplicative synaptic upscaling of glutamatergic synaptic strength in cultured cortical neurons. Inhibiting neuronal activity with tetrodotoxin (TTX) decreased the cytosine methylation of and increased the expression of genes encoding glutamate receptors and trafficking proteins, in turn increasing the amplitude but not frequency of miniature excitatory postsynaptic currents (mEPSCs), indicating synaptic upscaling rather than increased spontaneous activity. Inhibiting DNA methyltransferase (DNMT) activity, either by using the small-molecule inhibitor RG108 or by knocking down Dnmt1 and Dnmt3a, induced synaptic upscaling to a similar magnitude as exposure to TTX. Moreover, upscaling induced by DNMT inhibition required transcription; the RNA polymerase inhibitor actinomycin D blocked upscaling induced by DNMT inhibition. Knocking down the cytosine demethylase TET1 also blocked the upscaling effects of RG108. DNMT inhibition induced a multiplicative increase in mEPSC amplitude, indicating that the alterations in glutamate receptor abundance occurred in a coordinated manner throughout a neuron and were not limited to individual active synapses. Our data suggest that DNA methylation status controls transcription-dependent regulation of glutamatergic synaptic homeostasis. Furthermore, covalent DNA modifications may contribute to synaptic plasticity events that underlie the formation and stabilization of memories.
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Affiliation(s)
- Jarrod P Meadows
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Mikael C Guzman-Karlsson
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Scott Phillips
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Cassie Holleman
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jessica L Posey
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Jeremy J Day
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - John J Hablitz
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
| | - J David Sweatt
- Evelyn F. McKnight Brain Institute, Department of Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
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48
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Satterlee JS, Beckel-Mitchener A, Little R, Procaccini D, Rutter JL, Lossie AC. Neuroepigenomics: Resources, Obstacles, and Opportunities. NEUROEPIGENETICS 2015; 1:2-13. [PMID: 25722961 PMCID: PMC4337407 DOI: 10.1016/j.nepig.2014.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Long-lived post-mitotic cells, such as the majority of human neurons, must respond effectively to ongoing changes in neuronal stimulation or microenvironmental cues through transcriptional and epigenomic regulation of gene expression. The role of epigenomic regulation in neuronal function is of fundamental interest to the neuroscience community, as these types of studies have transformed our understanding of gene regulation in post-mitotic cells. This perspective article highlights many of the resources available to researchers interested in neuroepigenomic investigations and discusses some of the current obstacles and opportunities in neuroepigenomics.
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Affiliation(s)
- John S. Satterlee
- National Institute on Drug Abuse (NIDA), Division of Basic Neurobiology and Behavioral Research, 6001 Executive Boulevard, Bethesda, MD 20850, USA
| | - Andrea Beckel-Mitchener
- National Institute on Mental Health (NIMH), Division of Neuroscience and Basic Behavioral Science, 6001 Executive Boulevard Bethesda, MD 20892-9641, USA
| | - Roger Little
- National Institute on Drug Abuse (NIDA), Division of Basic Neurobiology and Behavioral Research, 6001 Executive Boulevard, Bethesda, MD 20850, USA
| | - Dena Procaccini
- National Institute on Drug Abuse (NIDA), Division of Basic Neurobiology and Behavioral Research, 6001 Executive Boulevard, Bethesda, MD 20850, USA
| | - Joni L. Rutter
- National Institute on Drug Abuse (NIDA), Division of Basic Neurobiology and Behavioral Research, 6001 Executive Boulevard, Bethesda, MD 20850, USA
| | - Amy C. Lossie
- Office of Behavioral and Social Sciences Research (OBSSR), Division of Program Coordination, Planning, and Strategic Initiatives, Office of the Director/National Institutes of Health (NIH), 31 Center Drive, Bethesda, MD 20892, USA
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49
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Multiple cellular cascades participate in long-term potentiation and in hippocampus-dependent learning. Brain Res 2014; 1621:73-81. [PMID: 25482663 DOI: 10.1016/j.brainres.2014.11.033] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 11/15/2014] [Indexed: 02/02/2023]
Abstract
Since its discovery by Bliss and Lomo, the phenomenon of long-term potentiation (LTP) has been extensively studied, as it was viewed as a potential cellular mechanism of learning and memory. Over the years, many signaling cascades have been implicated in its induction, consolidation and maintenance, raising questions regarding its real significance. Here, we review several of the most commonly studie signaling cascades and discuss how they converge on a common set of mechanisms likely to be involved in the maintenance of LTP. We further argue that the existence of cross-talks between these different signaling cascades can not only account for several discrepancies in the literature, but also account for the existence of different forms of LTP, which can be engaged by different types of stimulus parameters under different experimental conditions. Finally, we discuss how the understanding of the diversity of LTP mechanisms can help us understand the diversity of the types of learning and memory. This article is part of a Special Issue entitled SI: Brain and Memory.
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50
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Hardeland R. Melatonin, noncoding RNAs, messenger RNA stability and epigenetics--evidence, hints, gaps and perspectives. Int J Mol Sci 2014; 15:18221-52. [PMID: 25310649 PMCID: PMC4227213 DOI: 10.3390/ijms151018221] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/21/2014] [Accepted: 09/24/2014] [Indexed: 02/06/2023] Open
Abstract
Melatonin is a highly pleiotropic regulator molecule, which influences numerous functions in almost every organ and, thus, up- or down-regulates many genes, frequently in a circadian manner. Our understanding of the mechanisms controlling gene expression is actually now expanding to a previously unforeseen extent. In addition to classic actions of transcription factors, gene expression is induced, suppressed or modulated by a number of RNAs and proteins, such as miRNAs, lncRNAs, piRNAs, antisense transcripts, deadenylases, DNA methyltransferases, histone methylation complexes, histone demethylases, histone acetyltransferases and histone deacetylases. Direct or indirect evidence for involvement of melatonin in this network of players has originated in different fields, including studies on central and peripheral circadian oscillators, shift work, cancer, inflammation, oxidative stress, aging, energy expenditure/obesity, diabetes type 2, neuropsychiatric disorders, and neurogenesis. Some of the novel modulators have also been shown to participate in the control of melatonin biosynthesis and melatonin receptor expression. Future work will need to augment the body of evidence on direct epigenetic actions of melatonin and to systematically investigate its role within the network of oscillating epigenetic factors. Moreover, it will be necessary to discriminate between effects observed under conditions of well-operating and deregulated circadian clocks, and to explore the possibilities of correcting epigenetic malprogramming by melatonin.
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Affiliation(s)
- Rüdiger Hardeland
- Johann Friedrich Blumenbach Institute of Zoology and Anthropology, University of Göttingen, Berliner Str. 28, Göttingen D-37073, Germany.
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