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Spirrison AN, Lannigan DA. RSK1 and RSK2 as therapeutic targets: an up-to-date snapshot of emerging data. Expert Opin Ther Targets 2024; 28:1047-1059. [PMID: 39632509 PMCID: PMC11801519 DOI: 10.1080/14728222.2024.2433123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Accepted: 11/19/2024] [Indexed: 12/07/2024]
Abstract
INTRODUCTION The four members of the p90 ribosomal S6 kinase (RSK) family are serine/threonine protein kinases, which are phosphorylated and activated by ERK1/2. RSK1/2/3 are further phosphorylated by PDK1. Receiving inputs from two major signaling pathways places RSK as a key signaling node in numerous pathologies. A plethora of RSK1/2 substrates have been identified, and in the majority of cases the causative roles these RSK substrates play in the pathology are unknown. AREAS COVERED The majority of studies have focused on RSK1/2 and their functions in a diverse group of cancers. However, RSK1/2 are known to have important functions in cardiovascular disease and neurobiological disorders. Based on the literature, we identified substrates that are common in these pathologies with the goal of identifying fundamental physiological responses to RSK1/2. EXPERT OPINION The core group of targets in pathologies driven by RSK1/2 are associated with the immune response. However, there is a paucity of the literature addressing RSK function in inflammation, which is critical to know as the pan RSK inhibitor, PMD-026, is entering phase II clinical trials for metastatic breast cancer. A RSK inhibitor has the potential to be used in numerous diverse diseases and disorders.
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Affiliation(s)
| | - Deborah A. Lannigan
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN
- Department of Pathology, Microbiology & Immunology, Vanderbilt University Medical Center, Nashville, TN
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2
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Morice E, Enderlin V, Gautron S, Laroche S. Contrasting Functions of Mitogen- and Stress-activated Protein Kinases 1 and 2 in Recognition Memory and In Vivo Hippocampal Synaptic Transmission. Neuroscience 2021; 463:70-85. [PMID: 33722673 DOI: 10.1016/j.neuroscience.2021.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 11/28/2022]
Abstract
The mitogen-activated protein kinases (MAPK) are major signaling components of intracellular pathways required for memory consolidation. Mitogen- and stress-activated protein kinases 1 and 2 (MSK1 and MSK2) mediate signal transduction downstream of MAPK. MSKs are activated by Extracellular-signal Regulated Kinase 1/2 (ERK1/2) and p38 MAPK. In turn, they can activate cyclic AMP-response-element-binding protein (CREB), thereby modulating the expression of immediate early genes crucial for the formation of long-term memories. While MSK1 has been previously implicated in certain forms of learning and memory, little is known concerning MSK2. Our goal was to explore the respective contribution of MSK1 and MSK2 in hippocampal synaptic transmission and plasticity and hippocampal-dependent recognition memory. In Msk1- and Msk2-knockout mice, we evaluated object and object-place recognition memory, basal synaptic transmission, paired-pulse facilitation (PPF) and inhibition (PPI), and the capacity to induce and sustain long-term potentiation (LTP) in vivo. We also assessed the level of two proteins downstream in the MAPK/ERK1/2 pathway crucial for long-term memory, CREB and the immediate early gene (IEG) Early growth response 1 (EGR1). Loss of Msk1, but not of Msk2, affected excitatory synaptic transmission at perforant path-to-dentate granule cell synapses, altered short-term presynaptic plasticity, impaired selectively long-term spatial recognition memory, and decreased basal levels of CREB and its activated form. LTP in vivo and LTP-induced CREB phosphorylation and EGR1 expression were unchanged after Msk1 or Msk2 deletion. Our findings demonstrate a dissimilar contribution of MSKs proteins in cognitive processes and suggest that Msk1 loss-of-function only has a deleterious impact on neuronal activity and hippocampal-dependent memory consolidation.
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Affiliation(s)
- Elise Morice
- Sorbonne Université, INSERM, CNRS, Neuroscience Paris Seine, Institut de Biologie Paris Seine, 75005 Paris, France; University Paris-Saclay, CNRS, Paris-Saclay Neuroscience Institute, 91405 Orsay, France.
| | - Valérie Enderlin
- University Paris-Saclay, CNRS, Paris-Saclay Neuroscience Institute, 91405 Orsay, France.
| | - Sophie Gautron
- Sorbonne Université, INSERM, CNRS, Neuroscience Paris Seine, Institut de Biologie Paris Seine, 75005 Paris, France.
| | - Serge Laroche
- University Paris-Saclay, CNRS, Paris-Saclay Neuroscience Institute, 91405 Orsay, France.
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3
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Fischer M, Raabe T. Animal Models for Coffin-Lowry Syndrome: RSK2 and Nervous System Dysfunction. Front Behav Neurosci 2018; 12:106. [PMID: 29875643 PMCID: PMC5974046 DOI: 10.3389/fnbeh.2018.00106] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 05/07/2018] [Indexed: 01/07/2023] Open
Abstract
Loss of function mutations in the rsk2 gene cause Coffin-Lowry syndrome (CLS), which is associated with multiple symptoms including severe mental disabilities. Despite the characterization of ribosomal S6 kinase 2 (RSK2) as a protein kinase acting as a downstream effector of the well characterized ERK MAP-kinase signaling pathway, it turns out to be a challenging task to link RSK2 to specific neuronal processes dysregulated in case of mutation. Animal models such as mouse and Drosophila combine advanced genetic manipulation tools with in vivo imaging techniques, high-resolution connectome analysis and a variety of behavioral assays, thereby allowing for an in-depth analysis for gene functions in the nervous system. Although modeling mental disability in animal systems has limitations because of the complexity of phenotypes, the influence of genetic variation and species-specific characteristics at the neural circuit and behavioral level, some common aspects of RSK2 function in the nervous system have emerged, which will be presented. Only with this knowledge our understanding of the pathophysiology of CLS can be improved, which might open the door for development of potential intervention strategies.
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Affiliation(s)
- Matthias Fischer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Würzburg, Würzburg, Germany
| | - Thomas Raabe
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
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4
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Beck K, Hovhanyan A, Menegazzi P, Helfrich-Förster C, Raabe T. Drosophila RSK Influences the Pace of the Circadian Clock by Negative Regulation of Protein Kinase Shaggy Activity. Front Mol Neurosci 2018; 11:122. [PMID: 29706866 PMCID: PMC5908959 DOI: 10.3389/fnmol.2018.00122] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/28/2018] [Indexed: 11/18/2022] Open
Abstract
Endogenous molecular circadian clocks drive daily rhythmic changes at the cellular, physiological, and behavioral level for adaptation to and anticipation of environmental signals. The core molecular system consists of autoregulatory feedback loops, where clock proteins inhibit their own transcription. A complex and not fully understood interplay of regulatory proteins influences activity, localization and stability of clock proteins to set the pace of the clock. This study focuses on the molecular function of Ribosomal S6 Kinase (RSK) in the Drosophila melanogaster circadian clock. Mutations in the human rsk2 gene cause Coffin–Lowry syndrome, which is associated with severe mental disabilities. Knock-out studies with Drosophila ortholog rsk uncovered functions in synaptic processes, axonal transport and adult behavior including associative learning and circadian activity. However, the molecular targets of RSK remain elusive. Our experiments provide evidence that RSK acts in the key pace maker neurons as a negative regulator of Shaggy (SGG) kinase activity, which in turn determines timely nuclear entry of the clock proteins Period and Timeless to close the negative feedback loop. Phosphorylation of serine 9 in SGG is mediated by the C-terminal kinase domain of RSK, which is in agreement with previous genetic studies of RSK in the circadian clock but argues against the prevailing view that only the N-terminal kinase domain of RSK proteins carries the effector function. Our data provide a mechanistic explanation how RSK influences the molecular clock and imply SGG S9 phosphorylation by RSK and other kinases as a convergence point for diverse cellular and external stimuli.
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Affiliation(s)
- Katherina Beck
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Anna Hovhanyan
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
| | - Pamela Menegazzi
- Institute of Neurobiology and Genetics, Biozentrum, University of Würzburg, Würzburg, Germany
| | | | - Thomas Raabe
- Institute of Medical Radiation and Cell Research, Biozentrum, University of Würzburg, Würzburg, Germany
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5
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Selective alteration of adult hippocampal neurogenesis and impaired spatial pattern separation performance in the RSK2-deficient mouse model of Coffin-Lowry syndrome. Neurobiol Dis 2018; 115:69-81. [PMID: 29627578 DOI: 10.1016/j.nbd.2018.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 03/07/2018] [Accepted: 04/04/2018] [Indexed: 01/12/2023] Open
Abstract
Adult neurogenesis is involved in certain hippocampus-dependent cognitive functions and is linked to psychiatric diseases including intellectual disabilities. The Coffin-Lowry syndrome (CLS) is a developmental disorder caused by mutations in the Rsk2 gene and characterized by intellectual disabilities associated with growth retardation. How RSK2-deficiency leads to cognitive dysfunctions in CLS is however poorly understood. Here, using Rsk2 Knock-Out mice, we characterized the impact of RSK2 deficiency on adult hippocampal neurogenesis in vivo. We report that the absence of RSK2 does not affect basal proliferation, differentiation and survival of dentate gyrus adult-born neurons but alters the maturation progression of young immature newborn neurons. Moreover, when RSK2-deficient mice were submitted to spatial learning, in contrast to wild-type mice, proliferation of adult generated neurons was decreased and no pro-survival effect of learning was observed. Thus, learning failed to recruit a selective population of young newborn neurons in association with deficient long-term memory recall. Given the proposed role of the dentate gyrus and of adult-generated newborn neurons in hippocampal-dependent pattern separation function, we explored this function in a delayed non-matching to place task and in an object-place pattern separation task and report severe deficits in spatial pattern separation in Rsk2-KO mice. Together, this study reveals a previously unknown role for RSK2 in the early stages of maturation and learning-dependent involvement of adult-born dentate gyrus neurons. These alterations associated with a deficit in the ability of RSK2-deficient mice to finely discriminate relatively similar spatial configurations, may contribute to cognitive dysfunction in CLS.
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Pohodich AE, Yalamanchili H, Raman AT, Wan YW, Gundry M, Hao S, Jin H, Tang J, Liu Z, Zoghbi HY. Forniceal deep brain stimulation induces gene expression and splicing changes that promote neurogenesis and plasticity. eLife 2018; 7:34031. [PMID: 29570050 PMCID: PMC5906096 DOI: 10.7554/elife.34031] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 03/22/2018] [Indexed: 12/12/2022] Open
Abstract
Clinical trials are currently underway to assess the efficacy of forniceal deep brain stimulation (DBS) for improvement of memory in Alzheimer's patients, and forniceal DBS has been shown to improve learning and memory in a mouse model of Rett syndrome (RTT), an intellectual disability disorder caused by loss-of-function mutations in MECP2. The mechanism of DBS benefits has been elusive, however, so we assessed changes in gene expression, splice isoforms, DNA methylation, and proteome following acute forniceal DBS in wild-type mice and mice lacking Mecp2. We found that DBS upregulates genes involved in synaptic function, cell survival, and neurogenesis and normalized expression of ~25% of the genes altered in Mecp2-null mice. Moreover, DBS induced expression of 17-24% of the genes downregulated in other intellectual disability mouse models and in post-mortem human brain tissue from patients with Major Depressive Disorder, suggesting forniceal DBS could benefit individuals with a variety of neuropsychiatric disorders.
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Affiliation(s)
- Amy E Pohodich
- Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States
| | - Hari Yalamanchili
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Ayush T Raman
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, United States
| | - Ying-Wooi Wan
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Michael Gundry
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
| | - Shuang Hao
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Section of Neurology, Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Haijing Jin
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, United States
| | - Jianrong Tang
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Section of Neurology, Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Zhandong Liu
- Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Graduate Program in Quantitative and Computational Biosciences, Baylor College of Medicine, Houston, United States.,Section of Neurology, Department of Pediatrics, Baylor College of Medicine, Houston, United States
| | - Huda Y Zoghbi
- Department of Neuroscience, Baylor College of Medicine, Houston, United States.,Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, United States.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States.,Howard Hughes Medical Institute, Baylor College of Medicine, Houston, United States
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7
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Fischer M, Cabello V, Popp S, Krackow S, Hommers L, Deckert J, Lesch KP, Schmitt-Böhrer AG. Rsk2 Knockout Affects Emotional Behavior in the IntelliCage. Behav Genet 2017; 47:434-448. [PMID: 28585192 DOI: 10.1007/s10519-017-9853-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 05/25/2017] [Indexed: 12/31/2022]
Abstract
Ribosomal s6 kinase 2 is a growth factor activated serine/threonine kinase and member of the ERK signaling pathway. Mutations in the Rsk2 gene cause Coffin-Lowry syndrome, a rare syndromic form of intellectual disability. The Rsk2 KO mouse model was shown to have learning and memory defects. We focused on the investigation of the emotional behavioral phenotype of Rsk2 KO mice mainly in the IntelliCage. They exhibited an anti-depressive, sucrose reward seeking phenotype and showed reduced anxiety. Spontaneous activity was increased in some conventional tests. However, KO mice did not show defects in place learning, working memory and motor impulsivity. In addition, we found changes of the monoaminergic system in HPLC and qRT-PCR experiments. Taken together, RSK2 not only plays a role in cognitive processes but also in emotional and reward-related behaviors.
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Affiliation(s)
- Matthias Fischer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany.
| | - Victoria Cabello
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany
| | - Sandy Popp
- Laboratory of Translational Neuroscience, Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany
| | - Sven Krackow
- Institute of Anatomy, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Leif Hommers
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany
| | - Jürgen Deckert
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany
| | - Klaus-Peter Lesch
- Laboratory of Translational Neuroscience, Division of Molecular Psychiatry, Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany.,Department of Psychiatry and Psychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, The Netherlands.,Laboratory of Psychiatric Neurobiology, Institute of Molecular Medicine, I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Angelika G Schmitt-Böhrer
- Department of Psychiatry, Psychosomatics and Psychotherapy, Center of Mental Health, University Hospital of Wuerzburg, Margarete-Höppel-Platz 1, 97080, Wuerzburg, Germany
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8
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625 kb microduplication at Xp22.12 including RPS6KA3 in a child with mild intellectual disability. J Hum Genet 2015; 60:777-80. [PMID: 26354035 DOI: 10.1038/jhg.2015.106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Revised: 07/09/2015] [Accepted: 07/13/2015] [Indexed: 11/09/2022]
Abstract
Here, we report on a patient with a 625 kb duplication in Xp22.12, detected by array comparative genomic hybridization (CGH). The duplicated region contains only one gene, RPS6KA3, that results in partial duplication. The same duplication was present in his mother and his maternal uncle. This partial duplication inhibits the RPS6KA3 expression, mimicking the effect of loss-of-function mutations associated with Coffin-Lowry syndrome (CLS). The phenotype of the patient here presented is not fully evocative of this syndrome because he does not present some of the facial, digital and skeletal abnormalities that are considered the main diagnostic features of CLS. This case is one of the few examples where RPS6KA3 mutations are associated with a non-specific X-linked mental retardation.
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9
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Beck K, Ehmann N, Andlauer TFM, Ljaschenko D, Strecker K, Fischer M, Kittel RJ, Raabe T. Loss of the Coffin-Lowry syndrome-associated gene RSK2 alters ERK activity, synaptic function and axonal transport in Drosophila motoneurons. Dis Model Mech 2015; 8:1389-400. [PMID: 26398944 PMCID: PMC4631788 DOI: 10.1242/dmm.021246] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 08/27/2015] [Indexed: 01/06/2023] Open
Abstract
Plastic changes in synaptic properties are considered as fundamental for adaptive behaviors. Extracellular-signal-regulated kinase (ERK)-mediated signaling has been implicated in regulation of synaptic plasticity. Ribosomal S6 kinase 2 (RSK2) acts as a regulator and downstream effector of ERK. In the brain, RSK2 is predominantly expressed in regions required for learning and memory. Loss-of-function mutations in human RSK2 cause Coffin-Lowry syndrome, which is characterized by severe mental retardation and low IQ scores in affected males. Knockout of RSK2 in mice or the RSK ortholog in Drosophila results in a variety of learning and memory defects. However, overall brain structure in these animals is not affected, leaving open the question of the pathophysiological consequences. Using the fly neuromuscular system as a model for excitatory glutamatergic synapses, we show that removal of RSK function causes distinct defects in motoneurons and at the neuromuscular junction. Based on histochemical and electrophysiological analyses, we conclude that RSK is required for normal synaptic morphology and function. Furthermore, loss of RSK function interferes with ERK signaling at different levels. Elevated ERK activity was evident in the somata of motoneurons, whereas decreased ERK activity was observed in axons and the presynapse. In addition, we uncovered a novel function of RSK in anterograde axonal transport. Our results emphasize the importance of fine-tuning ERK activity in neuronal processes underlying higher brain functions. In this context, RSK acts as a modulator of ERK signaling.
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Affiliation(s)
- Katherina Beck
- University of Würzburg, Institute of Medical Radiation and Cell Research, Versbacherstraße 5, Würzburg D-97078, Germany
| | - Nadine Ehmann
- University of Würzburg, Institute of Physiology, Department of Neurophysiology, Röntgenring 9, Würzburg D-97070, Germany
| | - Till F M Andlauer
- University of Würzburg, Rudolf Virchow Center, DFG Research Center for Experimental Biomedicine, Josef-Schneider-Straße 2, Würzburg D-97080, Germany Freie Universität Berlin, Institute of Biology, Takusstraße 6, Berlin D-14195, Germany Max Planck Institute of Colloidals and Interfaces, Am Mühlenberg 1, Potsdam D-14476, Germany
| | - Dmitrij Ljaschenko
- University of Würzburg, Institute of Physiology, Department of Neurophysiology, Röntgenring 9, Würzburg D-97070, Germany
| | - Katrin Strecker
- University of Würzburg, Institute of Medical Radiation and Cell Research, Versbacherstraße 5, Würzburg D-97078, Germany
| | - Matthias Fischer
- University Hospital Würzburg, Department of Psychiatry, Psychosomatics and Psychotherapy, Füchsleinstraße 15, Würzburg 97080, Germany
| | - Robert J Kittel
- University of Würzburg, Institute of Physiology, Department of Neurophysiology, Röntgenring 9, Würzburg D-97070, Germany
| | - Thomas Raabe
- University of Würzburg, Institute of Medical Radiation and Cell Research, Versbacherstraße 5, Würzburg D-97078, Germany
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10
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Lim HC, Xie L, Zhang W, Li R, Chen ZC, Wu GZ, Cui SS, Tan EK, Zeng L. Ribosomal S6 Kinase 2 (RSK2) maintains genomic stability by activating the Atm/p53-dependent DNA damage pathway. PLoS One 2013; 8:e74334. [PMID: 24086335 PMCID: PMC3781089 DOI: 10.1371/journal.pone.0074334] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 07/31/2013] [Indexed: 12/17/2022] Open
Abstract
Ribosomal S6 Kinase 2 (RSK2) is a member of the p90RSK family of serine/threonine kinases, which are widely expressed and respond to many growth factors, peptide hormones, and neurotransmitters. Loss-of function mutations in the RPS6KA3 gene, which encodes the RSK2 protein, have been implicated in Coffin-Lowry Syndrome (CLS), an X-linked mental retardation disorder associated with cognitive deficits and behavioral impairments. However, the cellular and molecular mechanisms underlying this neurological disorder are not known. Recent evidence suggests that defective DNA damage signaling might be associated with neurological disorders, but the role of RSK2 in the DNA damage pathway remains to be elucidated. Here, we show that Adriamycin-induced DNA damage leads to the phosphorylation of RSK2 at Ser227 and Thr577 in the chromatin fraction, promotes RSK2 nuclear translocation, and enhances RSK2 and Atm interactions in the nuclear fraction. Furthermore, using RSK2 knockout mouse fibroblasts and RSK2-deficient cells from CLS patients, we demonstrate that ablation of RSK2 impairs the phosphorylation of Atm at Ser1981 and the phosphorylation of p53 at Ser18 (mouse) or Ser15 (human) in response to genotoxic stress. We also show that RSK2 affects p53-mediated downstream cellular events in response to DNA damage, that RSK2 knockout relieves cell cycle arrest at the G2/M phase, and that an increased number of γH2AX foci, which are associated with defects in DNA repair, are present in RSK2-deficient cells. Taken together, our findings demonstrated that RSK2 plays an important role in the DNA damage pathway that maintains genomic stability by mediating cell cycle progression and DNA repair.
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Affiliation(s)
- Han Chi Lim
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, Singapore
| | - Li Xie
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, Singapore
| | - Wei Zhang
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, Singapore
| | - Rong Li
- Experimental Therapeutics Centre, c/o Biomedical Sciences Institutes (BMSI), A*STAR, Singapore, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zhong-Can Chen
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Guang-Zhi Wu
- Department of Hand-surgery, China-Japan Union Hospital, Jilin University, Changchun City, Jinlin Province, People's Republic of China
| | - Shu-Sen Cui
- Department of Hand-surgery, China-Japan Union Hospital, Jilin University, Changchun City, Jinlin Province, People's Republic of China
| | - Eng King Tan
- Research Department, National Neuroscience Institute, Singapore, Singapore
- Neurology Department, National Neuroscience Institute, Singapore, Singapore
- Neuroscience & Behavioral Disorders program, DUKE-NUS Graduate Medical School, Singapore, Singapore
| | - Li Zeng
- Neural Stem Cell Research Lab, Research Department, National Neuroscience Institute, Singapore, Singapore
- Neuroscience & Behavioral Disorders program, DUKE-NUS Graduate Medical School, Singapore, Singapore
- * E-mail:
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11
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Morice E, Farley S, Poirier R, Dallerac G, Chagneau C, Pannetier S, Hanauer A, Davis S, Vaillend C, Laroche S. Defective synaptic transmission and structure in the dentate gyrus and selective fear memory impairment in the Rsk2 mutant mouse model of Coffin-Lowry syndrome. Neurobiol Dis 2013; 58:156-68. [PMID: 23742761 DOI: 10.1016/j.nbd.2013.05.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 04/18/2013] [Accepted: 05/27/2013] [Indexed: 12/20/2022] Open
Abstract
The Coffin-Lowry syndrome (CLS) is a syndromic form of intellectual disability caused by loss-of-function of the RSK2 serine/threonine kinase encoded by the rsk2 gene. Rsk2 knockout mice, a murine model of CLS, exhibit spatial learning and memory impairments, yet the underlying neural mechanisms are unknown. In the current study, we examined the performance of Rsk2 knockout mice in cued, trace and contextual fear memory paradigms and identified selective deficits in the consolidation and reconsolidation of hippocampal-dependent fear memories as task difficulty and hippocampal demand increase. Electrophysiological, biochemical and electron microscopy analyses were carried out in the dentate gyrus of the hippocampus to explore potential alterations in neuronal functions and structure. In vivo and in vitro electrophysiology revealed impaired synaptic transmission, decreased network excitability and reduced AMPA and NMDA conductance in Rsk2 knockout mice. In the absence of RSK2, standard measures of short-term and long-term potentiation (LTP) were normal, however LTP-induced CREB phosphorylation and expression of the transcription factors EGR1/ZIF268 were reduced and that of the scaffolding protein SHANK3 was blocked, indicating impaired activity-dependent gene regulation. At the structural level, the density of perforated and non-perforated synapses and of multiple spine boutons was not altered, however, a clear enlargement of spine neck width and post-synaptic densities indicates altered synapse ultrastructure. These findings show that RSK2 loss-of-function is associated in the dentate gyrus with multi-level alterations that encompass modifications of glutamate receptor channel properties, synaptic transmission, plasticity-associated gene expression and spine morphology, providing novel insights into the mechanisms contributing to cognitive impairments in CLS.
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Affiliation(s)
- Elise Morice
- Centre de Neurosciences Paris-Sud, CNRS, Orsay, France
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12
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Huidobro C, Fernandez AF, Fraga MF. The role of genetics in the establishment and maintenance of the epigenome. Cell Mol Life Sci 2013; 70:1543-73. [PMID: 23474979 PMCID: PMC11113764 DOI: 10.1007/s00018-013-1296-2] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 02/05/2013] [Accepted: 02/05/2013] [Indexed: 12/19/2022]
Abstract
Epigenetic mechanisms play an important role in gene regulation during development. DNA methylation, which is probably the most important and best-studied epigenetic mechanism, can be abnormally regulated in common pathologies, but the origin of altered DNA methylation remains unknown. Recent research suggests that these epigenetic alterations could depend, at least in part, on genetic mutations or polymorphisms in DNA methyltransferases and certain genes encoding enzymes of the one-carbon metabolism pathway. Indeed, the de novo methyltransferase 3B (DNMT3B) has been recently found to be mutated in several types of cancer and in the immunodeficiency, centromeric region instability and facial anomalies syndrome (ICF), in which these mutations could be related to the loss of global DNA methylation. In addition, mutations in glycine-N-methyltransferase (GNMT) could be associated with a higher risk of hepatocellular carcinoma and liver disease due to an unbalanced S-adenosylmethionine (SAM)/S-adenosylhomocysteine (SAH) ratio, which leads to aberrant methylation reactions. Also, genetic variants of chromatin remodeling proteins and histone tail modifiers are involved in genetic disorders like α thalassemia X-linked mental retardation syndrome, CHARGE syndrome, Cockayne syndrome, Rett syndrome, systemic lupus erythematous, Rubinstein-Taybi syndrome, Coffin-Lowry syndrome, Sotos syndrome, and facioescapulohumeral syndrome, among others. Here, we review the potential genetic alterations with a possible role on epigenetic factors and discuss their contribution to human disease.
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Affiliation(s)
- Covadonga Huidobro
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Agustin F. Fernandez
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
| | - Mario F. Fraga
- Cancer Epigenetics Laboratory, Institute of Oncology of Asturias (IUOPA-HUCA), University of Oviedo, Oviedo, Spain
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Madrid, Spain
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Mehmood T, Schneider A, Pannetier S, Hanauer A. Rsk2 Knockdown in PC12 Cells Results in Sp1 Dependent Increased Expression of the Gria2 Gene, Encoding the AMPA Receptor Subunit GluR2. Int J Mol Sci 2013; 14:3358-75. [PMID: 23389038 PMCID: PMC3588048 DOI: 10.3390/ijms14023358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 01/25/2013] [Accepted: 01/28/2013] [Indexed: 11/16/2022] Open
Abstract
The RSK2 protein is a member of the RSK serine-threonine protein kinase family and is encoded by the X-linked rps6ka3 gene in human. Highly heterogeneous loss-of-function mutations affecting this gene are responsible for a severe syndromic form of cognitive impairment, Coffin-Lowry syndrome. RSK2, which is highly conserved in mammals, acts at the distal end of the Ras-ERK signaling pathway and is activated in response to growth factors and neurotransmitters. RSK2 is highly expressed in the hippocampus, and Rsk2-KO mice display spatial learning and memory impairment. We recently showed that ERK1/2 activity is abnormally increased in the hippocampus of Rsk2-KO mice as well as the expression of the AMPA receptor subunit GluR2. The mechanism via which RSK2 deficiency affects the expression of GluR2 in neural cells was unknown. To address this issue we constitutively suppressed the expression of RSK2 in PC12 cells via vector-based shRNA in the present study. We show that Rsk2 silencing leads also to an elevation of ERK1/2 phosphorylation as well as of GluR2 expression and that the increased level of GluR2 expression results from the increased ERK1/2 activity on the transcription factor Sp1. Our results provide evidence that RSK2 modulates ERK1/2 activity on Sp1, which regulates GluR2 expression through transcriptional activation.
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Affiliation(s)
- Tahir Mehmood
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of Translational Medicine and Neurogenetics, INSERM U 964, CNRS UMR 1704, Université de Strasbourg, 67404 Illkirch, France; E-Mails: (A.S.); (S.P.)
- Department of Chemistry, University of Sargodha, 40100 Sargodha, Pakistan
- Authors to whom correspondence should be addressed; E-Mails: (T.M.); (A.H.); Tel.: +92-48-9230546 (T.M.); Fax: +92-48-3222121 (T.M.)
| | - Anne Schneider
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of Translational Medicine and Neurogenetics, INSERM U 964, CNRS UMR 1704, Université de Strasbourg, 67404 Illkirch, France; E-Mails: (A.S.); (S.P.)
| | - Solange Pannetier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of Translational Medicine and Neurogenetics, INSERM U 964, CNRS UMR 1704, Université de Strasbourg, 67404 Illkirch, France; E-Mails: (A.S.); (S.P.)
| | - André Hanauer
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Department of Translational Medicine and Neurogenetics, INSERM U 964, CNRS UMR 1704, Université de Strasbourg, 67404 Illkirch, France; E-Mails: (A.S.); (S.P.)
- Authors to whom correspondence should be addressed; E-Mails: (T.M.); (A.H.); Tel.: +92-48-9230546 (T.M.); Fax: +92-48-3222121 (T.M.)
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Millan MJ. An epigenetic framework for neurodevelopmental disorders: from pathogenesis to potential therapy. Neuropharmacology 2012; 68:2-82. [PMID: 23246909 DOI: 10.1016/j.neuropharm.2012.11.015] [Citation(s) in RCA: 151] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Revised: 11/11/2012] [Accepted: 11/22/2012] [Indexed: 12/12/2022]
Abstract
Neurodevelopmental disorders (NDDs) are characterized by aberrant and delayed early-life development of the brain, leading to deficits in language, cognition, motor behaviour and other functional domains, often accompanied by somatic symptoms. Environmental factors like perinatal infection, malnutrition and trauma can increase the risk of the heterogeneous, multifactorial and polygenic disorders, autism and schizophrenia. Conversely, discrete genetic anomalies are involved in Down, Rett and Fragile X syndromes, tuberous sclerosis and neurofibromatosis, the less familiar Phelan-McDermid, Sotos, Kleefstra, Coffin-Lowry and "ATRX" syndromes, and the disorders of imprinting, Angelman and Prader-Willi syndromes. NDDs have been termed "synaptopathies" in reference to structural and functional disturbance of synaptic plasticity, several involve abnormal Ras-Kinase signalling ("rasopathies"), and many are characterized by disrupted cerebral connectivity and an imbalance between excitatory and inhibitory transmission. However, at a different level of integration, NDDs are accompanied by aberrant "epigenetic" regulation of processes critical for normal and orderly development of the brain. Epigenetics refers to potentially-heritable (by mitosis and/or meiosis) mechanisms controlling gene expression without changes in DNA sequence. In certain NDDs, prototypical epigenetic processes of DNA methylation and covalent histone marking are impacted. Conversely, others involve anomalies in chromatin-modelling, mRNA splicing/editing, mRNA translation, ribosome biogenesis and/or the regulatory actions of small nucleolar RNAs and micro-RNAs. Since epigenetic mechanisms are modifiable, this raises the hope of novel therapy, though questions remain concerning efficacy and safety. The above issues are critically surveyed in this review, which advocates a broad-based epigenetic framework for understanding and ultimately treating a diverse assemblage of NDDs ("epigenopathies") lying at the interface of genetic, developmental and environmental processes. This article is part of the Special Issue entitled 'Neurodevelopmental Disorders'.
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Affiliation(s)
- Mark J Millan
- Unit for Research and Discovery in Neuroscience, IDR Servier, 125 chemin de ronde, 78290 Croissy sur Seine, Paris, France.
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Abstract
Genetic causes of intellectual disability (ID) include mutations in proteins with various functions. However, many of these proteins are enriched in synapses and recent investigations point out their crucial role in the subtle regulation of synaptic activity and dendritic spine morphogenesis. Moreover, in addition to genetic data, functional and animal model studies are providing compelling evidence that supports the emerging unifying synapse-based theory for cognitive deficit. In this review, we highlight ID-related gene products involved in synaptic morphogenesis and function, with a particular focus on the emergent signaling pathways involved in synaptic plasticity whose disruption results in cognitive deficit.
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Hackmann K, Matko S, Gerlach EM, von der Hagen M, Klink B, Schrock E, Rump A, Di Donato N. Partial deletion of GLRB and GRIA2 in a patient with intellectual disability. Eur J Hum Genet 2012; 21:112-4. [PMID: 22669415 DOI: 10.1038/ejhg.2012.97] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We report about the partial de novo loss of GLRB and GRIA2 in an individual with intellectual disability (ID). No additional mutations were found in either gene. GLRB itself does not seem to be a good candidate as it causes autosomal recessive hyperekplexia and no symptoms were found in the patient. Mutations of GRIA2 have not been described as cause of ID to date. Nonetheless, it is a very attractive candidate because it encodes a subunit of a glutamate receptor, which is highly expressed in postsynaptic structures and has an important role in signal transduction across synapses. Although we were able to isolate a fragment of a fusion transcript of both genes from the patient's blood, we were not able to isolate a transcript with an open reading frame throughout the entire length. The reading frame could be restored by differential splicing, which might take place in brain tissue but not in blood. We assume that either haploinsufficiency of GRIA2 or a GLRB/GRIA2 fusion gene leading to a protein with dominant-negative properties is causing the phenotype of the patient.
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Affiliation(s)
- Karl Hackmann
- Institut für Klinische Genetik, Medizinische Fakultät Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.
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Schneider A, Mehmood T, Pannetier S, Hanauer A. Altered ERK/MAPK signaling in the hippocampus of the mrsk2_KO mouse model of Coffin-Lowry syndrome. J Neurochem 2011; 119:447-59. [PMID: 21838783 DOI: 10.1111/j.1471-4159.2011.07423.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Coffin-Lowry syndrome is a syndromic form of mental retardation caused by mutations of the Rps6ka3 gene encoding ribosomal s6 kinase (RSK)2. RSK2 belongs to a family containing four members in mammals: RSK1-4. RSKs are serine/threonine kinases and cytosolic substrates of extracellular signal-regulated kinase (ERK) in the Ras/MAPK signaling pathway. RSK2 is highly expressed in the hippocampus, and mrsk2_KO mice display spatial learning and memory impairment. In the present study, we provide evidence of abnormally increased phosphorylation of ERK1/2 in the hippocampus of mrsk2_KO mice. Further studies based on cultured hippocampal neurons revealed that glutamate activates ERK1/2 and RSKs, and confirmed a stronger activation of ERK1/2 in mrsk2_KO neurons than in WT cells. We, thus, provide further evidence that RSK2 exerts a feedback inhibitory effect on the ERK1/2 pathway. We also observed a transient sequestration of P-ERK1/2 in the cytoplasm upon glutamate stimulation. In addition, the transcription factors cAMP response element binding and Ets LiKe gene1 show over-activation in RSK2-deficient neurons. Finally, c-Fos, Zif268 and Arc were significantly over-expressed in mrsk2_KO neurons upon glutamate stimulation. Importantly, the increased phosphorylation of other RSK family members observed in mutant neurons was unable to compensate for RSK2 deficiency. This aberrant ERK1/2 signaling can influence various neuronal functions, and thus play a significant role in cognitive dysfunction in mrsk2_KO mice and in the Coffin-Lowry syndrome.
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Affiliation(s)
- Anne Schneider
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
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