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Brito DV, Kupke J, Gulmez Karaca K, Oliveira AM. Regulation of neuronal plasticity by the DNA repair associated Gadd45 proteins. Curr Res Neurobiol 2022; 3:100031. [PMID: 36685757 PMCID: PMC9846468 DOI: 10.1016/j.crneur.2022.100031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/17/2022] [Accepted: 02/07/2022] [Indexed: 01/25/2023] Open
Abstract
Neurons respond rapidly to extracellular stimuli by activating signaling pathways that modulate the function of already synthetized proteins. Alternatively, signal transduction to the cell nucleus induces de novo synthesis of proteins required for long-lasting adaptations. These complementary strategies are necessary for neuronal plasticity processes that underlie, among other functions, the formation of memories. Nonetheless, it is still not fully understood how the coupling between different stimuli and the activity of constitutively and/or de novo expressed proteins gate neuronal plasticity. Here, we discuss the molecular functions of the Growth Arrest and DNA Damage 45 (Gadd45) family of proteins in neuronal adaptation. We highlight recent findings that indicate that Gadd45 family members regulate this function through multiple cellular processes (e.g., DNA demethylation, gene expression, RNA stability, MAPK signaling). We then summarize the regulation of Gadd45 expression in neurons and put forward the hypothesis that the constitutive and neuronal activity-induced pools of Gadd45 proteins have distinct and complementary roles in modulating neuronal plasticity. Therefore, we propose that Gadd45 proteins are essential for brain function and their dysfunction might underlie pathophysiological conditions such as neuropsychiatric disorders.
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Affiliation(s)
- David V.C. Brito
- Institute of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, INF 366, 69120, Heidelberg, Germany,Algarve Biomedical Center Research Institute (ABC-RI), University of Algarve, 8005-139, Faro, Portugal
| | - Janina Kupke
- Institute of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, INF 366, 69120, Heidelberg, Germany
| | - Kubra Gulmez Karaca
- Institute of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, INF 366, 69120, Heidelberg, Germany,Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center Kapittelweg 29, 6525, EN Nijmegen, the Netherlands
| | - Ana M.M. Oliveira
- Institute of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, INF 366, 69120, Heidelberg, Germany,Corresponding author. Institute of Neurobiology, Interdisciplinary Center for Neurosciences (IZN) Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany.
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Gulmez Karaca K, Brito DVC, Kupke J, Zeuch B, Oliveira AMM. Engram reactivation during memory retrieval predicts long-term memory performance in aged mice. Neurobiol Aging 2021; 101:256-261. [PMID: 33647524 DOI: 10.1016/j.neurobiolaging.2021.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Accepted: 01/20/2021] [Indexed: 10/22/2022]
Abstract
Age-related cognitive decline preferentially targets long-lasting episodic memories that require intact hippocampal function. Memory traces (or engrams) are believed to be encoded within the neurons activated during learning (neuronal ensembles), and recalled by reactivation of the same population. However, whether engram reactivation dictates memory performance late in life is not known. Here, we labeled neuronal ensembles formed during object location recognition learning in the dentate gyrus, and analyzed the reactivation of this population during long-term memory recall in young adult, cognitively impaired- and unimpaired-aged mice. We found that reactivation of memory-encoding neuronal ensembles at long-term memory recall was disrupted in impaired but not unimpaired-aged mice. Furthermore, we showed that the memory performance in the aged population correlated with the degree of engram reactivation at long-term memory recall. Overall, our data implicates recall-induced engram reactivation as a prediction factor of memory performance in aging. Moreover, our findings suggest impairments in neuronal ensemble stabilization and/or reactivation as an underlying mechanism in age-dependent cognitive decline.
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Affiliation(s)
- Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - David V C Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Janina Kupke
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Benjamin Zeuch
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Ana M M Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany.
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Brito DVC, Gulmez Karaca K, Kupke J, Frank L, Oliveira AMM. MeCP2 gates spatial learning-induced alternative splicing events in the mouse hippocampus. Mol Brain 2020; 13:156. [PMID: 33203444 PMCID: PMC7672966 DOI: 10.1186/s13041-020-00695-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/06/2020] [Indexed: 12/31/2022] Open
Abstract
Long-term memory formation is supported by functional and structural changes of neuronal networks, which rely on de novo gene transcription and protein synthesis. The modulation of the neuronal transcriptome in response to learning depends on transcriptional and post-transcriptional mechanisms. DNA methylation writers and readers regulate the activity-dependent genomic program required for memory consolidation. The most abundant DNA methylation reader, the Methyl CpG binding domain protein 2 (MeCP2), has been shown to regulate alternative splicing, but whether it establishes splicing events important for memory consolidation has not been investigated. In this study, we identified the alternative splicing profile of the mouse hippocampus in basal conditions and after a spatial learning experience, and investigated the requirement of MeCP2 for these processes. We observed that spatial learning triggers a wide-range of alternative splicing events in transcripts associated with structural and functional remodeling and that virus-mediated knockdown of MeCP2 impairs learning-dependent post-transcriptional responses of mature hippocampal neurons. Furthermore, we found that MeCP2 preferentially affected the splicing modalities intron retention and exon skipping and guided the alternative splicing of distinct set of genes in baseline conditions and after learning. Lastly, comparative analysis of the MeCP2-regulated transcriptome with the alternatively spliced mRNA pool, revealed that MeCP2 disruption alters the relative abundance of alternatively spliced isoforms without affecting the overall mRNA levels. Taken together, our findings reveal that adult hippocampal MeCP2 is required to finetune alternative splicing events in basal conditions, as well as in response to spatial learning. This study provides new insight into how MeCP2 regulates brain function, particularly cognitive abilities, and sheds light onto the pathophysiological mechanisms of Rett syndrome, that is characterized by intellectual disability and caused by mutations in the Mecp2 gene.
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Affiliation(s)
- David V C Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany.,Department of Cognitive Neuroscience, Radboud University Medical Center, 6500 HB, Nijmegen, The Netherlands.,Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, 6525 EN, Nijmegen, The Netherlands
| | - Janina Kupke
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany
| | - Lukas Frank
- Division of Chromatin Networks, German Cancer Research Center (DKFZ) and Bioquant (Heidelberg University), Heidelberg, Germany
| | - Ana M M Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Im Neuenheimer Feld 366, 69120, Heidelberg, Germany.
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Brito DVC, Gulmez Karaca K, Kupke J, Mudlaff F, Zeuch B, Gomes R, Lopes LV, Oliveira AMM. Modeling human age-associated increase in Gadd45γ expression leads to spatial recognition memory impairments in young adult mice. Neurobiol Aging 2020; 94:281-286. [PMID: 32711258 DOI: 10.1016/j.neurobiolaging.2020.06.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 05/22/2020] [Accepted: 06/27/2020] [Indexed: 12/18/2022]
Abstract
Aging is associated with the progressive decay of cognitive function. Hippocampus-dependent processes, such as the formation of spatial memory, are particularly vulnerable to aging. Currently, the molecular mechanisms responsible for age-dependent cognitive decline are largely unknown. Here, we investigated the expression and function of the growth arrest DNA damage gamma (Gadd45γ) during aging and cognition. We report that Gadd45γ expression is increased in the hippocampus of aged humans and that Gadd45γ overexpression in the young adult mouse hippocampus compromises cognition. Moreover, Gadd45γ overexpression in hippocampal neurons disrupted cAMP response element-binding protein signaling and the expression of well-established activity-regulated genes. This work shows that Gadd45γ expression is tightly controlled in the hippocampus and its disruption may be a mechanism contributing to age-related cognitive impairments observed in humans.
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Affiliation(s)
- David V C Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany; Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Janina Kupke
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Franziska Mudlaff
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany
| | - Benjamin Zeuch
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany; Directors' Research, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Rui Gomes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisbon, Portugal
| | - Luísa V Lopes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisbon, Portugal
| | - Ana M M Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, Heidelberg, Germany.
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Gulmez Karaca K, Brito DV, Oliveira AM. MeCP2: A Critical Regulator of Chromatin in Neurodevelopment and Adult Brain Function. Int J Mol Sci 2019; 20:ijms20184577. [PMID: 31527487 PMCID: PMC6769791 DOI: 10.3390/ijms20184577] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 01/08/2023] Open
Abstract
Methyl CpG binding protein 2 (MeCP2) was first identified as a nuclear protein with a transcriptional repressor role that recognizes DNA methylation marks. MeCP2 has a well-established function in neurodevelopment, as evidenced by the severe neurological impairments characteristic of the Rett syndrome (RTT) pathology and the MeCP2 duplication syndrome (MDS), caused by loss or gain of MeCP2 function, respectively. Research aimed at the underlying pathophysiological mechanisms of RTT and MDS has significantly advanced our understanding of MeCP2 functions in the nervous system. It has revealed, however, that MeCP2 has more varied and complex roles than previously thought. Here we review recent insights into the functions of MeCP2 in neurodevelopment and the less explored requirement for MeCP2 in adult brain function. We focus on the emerging view that MeCP2 is a global chromatin organizer. Finally, we discuss how the individual functions of MeCP2 in neurodevelopment and adulthood are linked to its role as a chromatin regulator.
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Affiliation(s)
- Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, 6525 EN Nijmegen, The Netherlands
| | - David V.C. Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
| | - Ana M.M. Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), Heidelberg University, 69120 Heidelberg, Germany; (K.G.K.)
- Correspondence: ; Tel.: +49-(0)6221-5416510
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Gulmez Karaca K, Brito DVC, Zeuch B, Oliveira AMM. Adult hippocampal MeCP2 preserves the genomic responsiveness to learning required for long-term memory formation. Neurobiol Learn Mem 2018; 149:84-97. [PMID: 29438740 DOI: 10.1016/j.nlm.2018.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Revised: 02/04/2018] [Accepted: 02/09/2018] [Indexed: 01/09/2023]
Abstract
MeCP2 is required both during postnatal neurodevelopment and throughout the adult life for brain function. Although it is well accepted that MeCP2 in the maturing nervous system is critical for establishing normal development, the functions of MeCP2 during adulthood are poorly understood. Particularly, the requirement of hippocampal MeCP2 for cognitive abilities in the adult is not studied. To characterize the role of MeCP2 in adult neuronal function and cognition, we used a temporal and region-specific disruption of MeCP2 expression in the hippocampus of adult male mice. We found that MeCP2 is required for long-term memory formation and that it controls the learning-induced transcriptional response of hippocampal neurons required for memory consolidation. Furthermore, we uncovered MeCP2 functions in the adult hippocampus that may underlie cognitive integrity. We showed that MeCP2 maintains the developmentally established chromatin configuration and epigenetic landscape of CA1 neurons throughout the adulthood, and that it regulates the expression of neuronal and immune-related genes in the adult hippocampus. Overall, our findings identify MeCP2 as a maintenance factor in the adult hippocampus that preserves signal responsiveness of the genome and allows for integrity of cognitive functions. This study provides new insight into how MeCP2 maintains adult brain functions, but also into the mechanisms underlying the cognitive impairments observed in RTT patients and highlights the understudied role of DNA methylation interpretation in adult cognitive processes.
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Affiliation(s)
- Kubra Gulmez Karaca
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), University of Heidelberg, INF 364, 69120 Heidelberg, Germany
| | - David V C Brito
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), University of Heidelberg, INF 364, 69120 Heidelberg, Germany
| | - Benjamin Zeuch
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), University of Heidelberg, INF 364, 69120 Heidelberg, Germany
| | - Ana M M Oliveira
- Department of Neurobiology, Interdisciplinary Centre for Neurosciences (IZN), University of Heidelberg, INF 364, 69120 Heidelberg, Germany.
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