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Stefanelli G, Makowski CE, Brimble MA, Hall M, Reda A, Creighton SD, Leonetti AM, McLean TAB, Zakaria JM, Baumbach J, Greer CB, Davidoff AM, Walters BJ, Murphy PJ, Zovkic IB. The histone chaperone Anp32e regulates memory formation, transcription, and dendritic morphology by regulating steady-state H2A.Z binding in neurons. Cell Rep 2021; 36:109551. [PMID: 34407406 PMCID: PMC8422973 DOI: 10.1016/j.celrep.2021.109551] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 06/08/2021] [Accepted: 07/27/2021] [Indexed: 12/12/2022] Open
Abstract
Rapid removal of histone H2A.Z from neuronal chromatin is a key step in learning-induced gene expression and memory formation, but mechanisms underlying learning-induced H2A.Z removal are unclear. Anp32e was recently identified as an H2A.Z-specific histone chaperone that removes H2A.Z from nucleosomes in dividing cells, but its role in non-dividing neurons is unclear. Moreover, prior studies investigated Anp32e function under steady-state rather than stimulus-induced conditions. Here, we show that Anp32e regulates H2A.Z binding in neurons under steady-state conditions, with lesser impact on stimulus-induced H2A.Z removal. Functionally, Anp32e depletion leads to H2A.Z-dependent impairment in transcription and dendritic arborization in cultured hippocampal neurons, as well as impaired recall of contextual fear memory and transcriptional regulation. Together, these data indicate that Anp32e regulates behavioral and morphological outcomes by preventing H2A.Z accumulation in chromatin rather than by regulating activity-mediated H2A.Z dynamics.
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Affiliation(s)
- Gilda Stefanelli
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Claire E Makowski
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Mark A Brimble
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Meaghan Hall
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Anas Reda
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Samantha D Creighton
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Amanda M Leonetti
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Timothy A B McLean
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada
| | - Jacqueline M Zakaria
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Jennet Baumbach
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Celeste B Greer
- Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA
| | - Andrew M Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Brandon J Walters
- Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada
| | - Patrick J Murphy
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642, USA.
| | - Iva B Zovkic
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3G3, Canada.
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2
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An Emerging Role of m6A in Memory: A Case for Translational Priming. Int J Mol Sci 2020; 21:ijms21207447. [PMID: 33050279 PMCID: PMC7589748 DOI: 10.3390/ijms21207447] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/03/2020] [Accepted: 10/05/2020] [Indexed: 12/30/2022] Open
Abstract
Investigation into the role of methylation of the adenosine base (m6A) of RNA has only recently begun, but it quickly became apparent that m6A is able to control and fine-tune many aspects of mRNA, from splicing to translation. The ability of m6A to regulate translation distally, away from traditional sites near the nucleus, quickly caught the eye of neuroscientists because of implications for selective protein translation at synapses. Work in the brain has demonstrated how m6A is functionally required for many neuronal functions, but two in particular are covered at length here: The role of m6A in 1) neuron development; and 2) memory formation. The purpose of this review is not to cover all data about m6A in the brain. Instead, this review will focus on connecting mechanisms of m6A function in neuron development, with m6A’s known function in memory formation. We will introduce the concept of “translational priming” and discuss how current data fit into this model, then speculate how m6A-mediated translational priming during memory consolidation can regulate learning and memory locally at the synapse.
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Creighton SD, Stefanelli G, Reda A, Zovkic IB. Epigenetic Mechanisms of Learning and Memory: Implications for Aging. Int J Mol Sci 2020; 21:E6918. [PMID: 32967185 PMCID: PMC7554829 DOI: 10.3390/ijms21186918] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/15/2022] Open
Abstract
The neuronal epigenome is highly sensitive to external events and its function is vital for producing stable behavioral outcomes, such as the formation of long-lasting memories. The importance of epigenetic regulation in memory is now well established and growing evidence points to altered epigenome function in the aging brain as a contributing factor to age-related memory decline. In this review, we first summarize the typical role of epigenetic factors in memory processing in a healthy young brain, then discuss the aspects of this system that are altered with aging. There is general agreement that many epigenetic marks are modified with aging, but there are still substantial inconsistencies in the precise nature of these changes and their link with memory decline. Here, we discuss the potential source of age-related changes in the epigenome and their implications for therapeutic intervention in age-related cognitive decline.
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Affiliation(s)
- Samantha D. Creighton
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
| | - Gilda Stefanelli
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
| | - Anas Reda
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S, Canada;
| | - Iva B. Zovkic
- Department of Psychology, University of Toronto Mississauga, Mississauga, ON L5L 1C6, Canada; (S.D.C.); (G.S.)
- Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S, Canada;
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4
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Bagchi DN, Battenhouse AM, Park D, Iyer VR. The histone variant H2A.Z in yeast is almost exclusively incorporated into the +1 nucleosome in the direction of transcription. Nucleic Acids Res 2020; 48:157-170. [PMID: 31722407 PMCID: PMC7145542 DOI: 10.1093/nar/gkz1075] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/22/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
Transcription start sites (TSS) in eukaryotes are characterized by a nucleosome-depleted region (NDR), which appears to be flanked upstream and downstream by strongly positioned nucleosomes incorporating the histone variant H2A.Z. H2A.Z associates with both active and repressed TSS and is important for priming genes for rapid transcriptional activation. However, the determinants of H2A.Z occupancy at specific nucleosomes and its relationship to transcription initiation remain unclear. To further elucidate the specificity of H2A.Z, we determined its genomic localization at single nucleosome resolution, as well as the localization of its chromatin remodelers Swr1 and Ino80. By analyzing H2A.Z occupancy in conjunction with RNA expression data that captures promoter-derived antisense initiation, we find that H2A.Z's bimodal incorporation on either side of the NDR is not a general feature of TSS, but is specifically a marker for bidirectional transcription, such that the upstream flanking -1 H2A.Z-containing nucleosome is more appropriately considered as a +1 H2A.Z nucleosome for antisense transcription. The localization of H2A.Z almost exclusively at the +1 nucleosome suggests that a transcription-initiation dependent process could contribute to its specific incorporation.
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Affiliation(s)
- Dia N Bagchi
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Livestrong Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA
| | - Anna M Battenhouse
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Livestrong Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA
| | - Daechan Park
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Livestrong Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA
| | - Vishwanath R Iyer
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Livestrong Cancer Institutes, Dell Medical School, University of Texas at Austin, Austin, TX 78712, USA
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Gretzinger TL, Tyagi M, Fontaine CJ, Cheema MS, González-Perez M, Freeman ME, Christie BR, Ausió J. Fetal alcohol spectrum disorder (FASD) affects the hippocampal levels of histone variant H2A.Z-2. Biochem Cell Biol 2019; 97:431-436. [PMID: 30605356 DOI: 10.1139/bcb-2018-0240] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fetal alcohol spectrum disorder (FASD) is caused by prenatal exposure to ethanol and has been linked to neurodevelopmental impairments. Alcohol has the potential to alter some of the epigenetic components that play a critical role during development. Previous studies have provided evidence that prenatal exposure to ethanol results in abnormal epigenetic patterns (i.e., hypomethylation) of the genome. The aim of this study was to determine how prenatal exposure to ethanol in rats affects the hippocampal levels of expression of two important brain epigenetic transcriptional regulators involved in synaptic plasticity and memory consolidation: methyl CpG-binding protein 2 (MeCP2) and histone variant H2A.Z. Unexpectedly, under the conditions used in this work we were not able to detect any changes in MeCP2. Interestingly, however, we observed a significant decrease in H2A.Z, accompanied by its chromatin redistribution in both female and male FASD rat pups. Moreover, the data from reverse-transcription qPCR later confirmed that this decrease in H2A.Z is mainly due to down-regulation of its H2A.Z-2 isoform gene expression. Altogether, these data provide strong evidence that prenatal exposure to ethanol alters histone variant H2A.Z during neurogenesis of rat hippocampus.
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Affiliation(s)
- Taylor L Gretzinger
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Monica Tyagi
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Christine J Fontaine
- b Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Manjinder S Cheema
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - María González-Perez
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Melissa E Freeman
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
| | - Brian R Christie
- b Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Juan Ausió
- a Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC V8W 3P6, Canada
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6
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Cheikhi A, Wallace C, St Croix C, Cohen C, Tang WY, Wipf P, Benos PV, Ambrosio F, Barchowsky A. Mitochondria are a substrate of cellular memory. Free Radic Biol Med 2019; 130:528-541. [PMID: 30472365 DOI: 10.1016/j.freeradbiomed.2018.11.028] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/19/2018] [Accepted: 11/21/2018] [Indexed: 12/26/2022]
Abstract
Cellular memory underlies cellular identity, and thus constitutes a unifying mechanism of genetic disposition, environmental influences, and cellular adaptation. Here, we demonstrate that enduring physicochemical changes of mitochondrial networks invoked by transient stress, a phenomenon we term 'mitoengrams', underlie the transgenerational persistence of epigenetically scripted cellular behavior. Using C2C12 myogenic stem-like cells, we show that stress memory elicited by transient, low-level arsenite exposure is stored within a self-renewing subpopulation of progeny cells in a mitochondrial-dependent fashion. Importantly, we demonstrate that erasure of mitoengrams by administration of mitochondria-targeted electron scavenger was sufficient to reset key epigenetic marks of cellular memory and redirect the identity of the mitoengram-harboring progeny cells to a non-stress-like state. Together, our findings indicate that mnemonic information emanating from mitochondria support the balance between the persistence and transience of cellular memory.
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Affiliation(s)
- Amin Cheikhi
- Division of Geriatric Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Callen Wallace
- Center for Biological Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Claudette St Croix
- Center for Biological Imaging, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Cell Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Charles Cohen
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Wan-Yee Tang
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA.
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Panagiotis V Benos
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Fabrisia Ambrosio
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA 15219, USA; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA.
| | - Aaron Barchowsky
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15261, USA; Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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7
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Dnmts and Tet target memory-associated genes after appetitive olfactory training in honey bees. Sci Rep 2015; 5:16223. [PMID: 26531238 PMCID: PMC4632027 DOI: 10.1038/srep16223] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/08/2015] [Indexed: 11/09/2022] Open
Abstract
DNA methylation and demethylation are epigenetic mechanisms involved in memory formation. In honey bees DNA methyltransferase (Dnmt) function is necessary for long-term memory to be stimulus specific (i.e. to reduce generalization). So far, however, it remains elusive which genes are targeted and what the time-course of DNA methylation is during memory formation. Here, we analyse how DNA methylation affects memory retention, gene expression, and differential methylation in stimulus-specific olfactory long-term memory formation. Out of 30 memory-associated genes investigated here, 9 were upregulated following Dnmt inhibition in trained bees. These included Dnmt3 suggesting a negative feedback loop for DNA methylation. Within these genes also the DNA methylation pattern changed during the first 24 hours after training. Interestingly, this was accompanied by sequential activation of the DNA methylation machinery (i.e. Dnmts and Tet). In sum, memory formation involves a temporally complex epigenetic regulation of memory-associated genes that facilitates stimulus specific long-term memory in the honey bee.
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Cheung P. You must remember this: How H2A.Z potentially links transcriptional memory to cognitive memory formation (comment on DOI 10.1002/bies.201400223). Bioessays 2015; 37:582-3. [DOI: 10.1002/bies.201500039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Peter Cheung
- Department of Biology; York University; Toronto ON Canada
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9
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Walters BJ, Zovkic IB. Building up and knocking down: an emerging role for epigenetics and proteasomal degradation in systems consolidation. Neuroscience 2015; 300:39-52. [PMID: 25967264 DOI: 10.1016/j.neuroscience.2015.05.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Revised: 04/18/2015] [Accepted: 05/03/2015] [Indexed: 01/30/2023]
Abstract
Memory formation is a protracted process in which recently acquired events are consolidated to produce stable and specific associations. Initially, newly acquired information undergoes cellular consolidation in the hippocampus, which transiently supports the storage of recently acquired memories. In contrast, remote, or "old" memories are maintained in the cortex and show almost complete independence from the hippocampus. Memories are transferred from the hippocampus to the cortex through a process termed systems consolidation. Emerging evidence suggests that recurrent activation, or "training" of the cortex by the hippocampus is vital to systems consolidation. This process involves prolonged waves of memory-related gene activity in the hippocampus and cortex long after the learning event has terminated. Indeed, molecular events occurring within hours and days of fear conditioning are essential for stabilizing and eventually transitioning the memory to the cortex. It is increasingly evident that molecular mechanisms that exhibit a capacity for prolonged activation may underlie systems consolidation. Processes that have the capacity to control protein abundance over long time scales, such as epigenetic modifications, are prime candidates for the molecular mechanism of systems consolidation. Indeed, recent work has established two types of epigenetic modifications as integral for systems consolidation. First, localized nucleosomal histone variant exchange and histone modifications are integral for early stages of systems consolidation, whereas DNA methylation appears to be utilized to form stable marks that support memory maintenance. Since systems consolidation also requires discrete and time-sensitive changes in protein abundance, additional mechanisms, such as protein degradation, need also be considered, although their role in systems consolidation has yet to be investigated. Here, we discuss the role of molecular mechanisms in systems consolidation and their implications for understanding how memories persist over time.
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Affiliation(s)
- B J Walters
- The Hospital for Sick Children, Department of Neuroscience and Mental Health, Toronto, ON, Canada
| | - I B Zovkic
- University of Toronto Mississauga, Department of Psychology, Mississauga, ON, Canada.
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