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Abstract
Over the past decade, it has become increasingly obvious that epigenetic mechanisms are an integral part of a multitude of brain functions that range from the development of the nervous system over basic neuronal functions to higher order cognitive processes. At the same time, a substantial body of evidence has surfaced indicating that several neurodevelopmental, neurodegenerative, and neuropsychiatric disorders are in part caused by aberrant epigenetic modifications. Because of their inherent plasticity, such pathological epigenetic modifications are readily amenable to pharmacological interventions and have thus raised justified hopes that the epigenetic machinery provides a powerful new platform for therapeutic approaches against these diseases. In this review, we give a detailed overview of the implication of epigenetic mechanisms in both physiological and pathological brain processes and summarize the state-of-the-art of "epigenetic medicine" where applicable. Despite, or because of, these new and exciting findings, it is becoming apparent that the epigenetic machinery in the brain is highly complex and intertwined, which underscores the need for more refined studies to disentangle brain-region and cell-type specific epigenetic codes in a given environmental condition. Clearly, the brain contains an epigenetic "hotspot" with a unique potential to not only better understand its most complex functions, but also to treat its most vicious diseases.
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Affiliation(s)
- Johannes Gräff
- Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
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2
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Kim D, Frank CL, Dobbin MM, Tsunemoto RK, Tu W, Peng PL, Guan JS, Lee BH, Moy LY, Giusti P, Broodie N, Mazitschek R, Delalle I, Haggarty SJ, Neve RL, Lu Y, Tsai LH. Deregulation of HDAC1 by p25/Cdk5 in neurotoxicity. Neuron 2009; 60:803-17. [PMID: 19081376 DOI: 10.1016/j.neuron.2008.10.015] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2008] [Revised: 09/02/2008] [Accepted: 10/09/2008] [Indexed: 12/19/2022]
Abstract
Aberrant cell-cycle activity and DNA damage are emerging as important pathological components in various neurodegenerative conditions. However, their underlying mechanisms are poorly understood. Here, we show that deregulation of histone deacetylase 1 (HDAC1) activity by p25/Cdk5 induces aberrant cell-cycle activity and double-strand DNA breaks leading to neurotoxicity. In a transgenic model for neurodegeneration, p25/Cdk5 activity elicited cell-cycle activity and double-strand DNA breaks that preceded neuronal death. Inhibition of HDAC1 activity by p25/Cdk5 was identified as an underlying mechanism for these events, and HDAC1 gain of function provided potent protection against DNA damage and neurotoxicity in cultured neurons and an in vivo model for ischemia. Our findings outline a pathological signaling pathway illustrating the importance of maintaining HDAC1 activity in the adult neuron. This pathway constitutes a molecular link between aberrant cell-cycle activity and DNA damage and is a potential target for therapeutics against diseases and conditions involving neuronal death.
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Affiliation(s)
- Dohoon Kim
- Howard Hughes Medical Institute, Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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3
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Kim D, Nguyen MD, Dobbin MM, Fischer A, Sananbenesi F, Rodgers JT, Delalle I, Baur JA, Sui G, Armour SM, Puigserver P, Sinclair DA, Tsai LH. SIRT1 deacetylase protects against neurodegeneration in models for Alzheimer's disease and amyotrophic lateral sclerosis. EMBO J 2007; 26:3169-79. [PMID: 17581637 PMCID: PMC1914106 DOI: 10.1038/sj.emboj.7601758] [Citation(s) in RCA: 786] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Accepted: 05/22/2007] [Indexed: 01/10/2023] Open
Abstract
A progressive loss of neurons with age underlies a variety of debilitating neurological disorders, including Alzheimer's disease (AD) and amyotrophic lateral sclerosis (ALS), yet few effective treatments are currently available. The SIR2 gene promotes longevity in a variety of organisms and may underlie the health benefits of caloric restriction, a diet that delays aging and neurodegeneration in mammals. Here, we report that a human homologue of SIR2, SIRT1, is upregulated in mouse models for AD, ALS and in primary neurons challenged with neurotoxic insults. In cell-based models for AD/tauopathies and ALS, SIRT1 and resveratrol, a SIRT1-activating molecule, both promote neuronal survival. In the inducible p25 transgenic mouse, a model of AD and tauopathies, resveratrol reduced neurodegeneration in the hippocampus, prevented learning impairment, and decreased the acetylation of the known SIRT1 substrates PGC-1alpha and p53. Furthermore, injection of SIRT1 lentivirus in the hippocampus of p25 transgenic mice conferred significant protection against neurodegeneration. Thus, SIRT1 constitutes a unique molecular link between aging and human neurodegenerative disorders and provides a promising avenue for therapeutic intervention.
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Affiliation(s)
- Dohoon Kim
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
- Division of Medical Sciences, Harvard Medical School, Boston, MA, USA
| | - Minh Dang Nguyen
- Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Matthew M Dobbin
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Andre Fischer
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Farahnaz Sananbenesi
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Joseph T Rodgers
- Dana Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cell Biology, Johns Hopkins University School of Medicine, Boston, MA, USA
| | - Ivana Delalle
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
| | - Joseph A Baur
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Guangchao Sui
- Department of Pathology, Harvard Medical School, Boston, MA, USA
| | - Sean M Armour
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Pere Puigserver
- Dana Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, MA, USA
- Department of Cell Biology, Johns Hopkins University School of Medicine, Boston, MA, USA
| | - David A Sinclair
- Department of Pathology and Paul F Glenn Laboratories for the Biological Mechanisms of Aging, Harvard Medical School, Boston, MA, USA
| | - Li-Huei Tsai
- Howard Hughes Medical Institute, Picower Insitute for Learning and Memory, Riken-MIT Neuroscience Research Center, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Boston, MA, USA
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Cruz JC, Kim D, Moy LY, Dobbin MM, Sun X, Bronson RT, Tsai LH. p25/cyclin-dependent kinase 5 induces production and intraneuronal accumulation of amyloid beta in vivo. J Neurosci 2006; 26:10536-41. [PMID: 17035538 PMCID: PMC6674706 DOI: 10.1523/jneurosci.3133-06.2006] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aberrant processing of the amyloid precursor protein (APP) and the subsequent accumulation of amyloid beta (Abeta) peptide has been widely established as a central event in Alzheimer's disease (AD) pathogenesis. The sequential cleavage steps required for the generation of Abeta are well outlined; however, there is a relative dearth of knowledge pertaining to signaling pathways and molecular mechanisms that can modulate this process. Here, we demonstrate a novel role for p25/cyclin-dependent kinase 5 (Cdk5) in regulating APP processing, Abeta peptide generation, and intraneuronal Abeta accumulation in inducible p25 transgenic and compound PD-APP transgenic mouse models that demonstrate deregulated Cdk5 activity and a neurodegenerative phenotype. Induction of p25 resulted in enhanced forebrain Abeta levels before any evidence of neuropathology in these mice. Intracellular Abeta accumulated in perinuclear regions and distended axons within the forebrains of these mice. Evidence for modulations in axonal transport or beta-site APP cleaving enzyme 1 protein levels and activity are presented as mechanisms that may account for the Abeta accumulation caused by p25/Cdk5 deregulation. Collectively, these findings delineate a novel pathological mechanism involving aberrant APP processing by p25/Cdk5 and have important implications in AD pathogenesis.
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Affiliation(s)
- Jonathan C. Cruz
- Department of Pathology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts 02115, and
| | - Dohoon Kim
- Department of Pathology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts 02115, and
| | - Lily Y. Moy
- Department of Pathology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts 02115, and
| | - Matthew M. Dobbin
- Department of Pathology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts 02115, and
| | - Xiaoyan Sun
- Center for Neurologic Diseases, Brigham and Women's Hospital, Program in Neuroscience, and
| | - Roderick T. Bronson
- Rodent Histopathology Core, Harvard Medical School, Boston, Massachusetts 02115
| | - Li-Huei Tsai
- Department of Pathology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts 02115, and
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