SIRT3 deregulation is linked to mitochondrial dysfunction in Alzheimer's disease |
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| Authors: | Yu Jin Hwang Seung Jae Hyeon Hyeonjoo Im Kyungeun Lee Victor E Alvarez Ann C McKee Soo‐Jong Um Manwook Hur Inhee Mook‐Jung Neil W Kowall Hoon Ryu |
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| Institution: | 1. Laboratory for Neuronal Gene Regulation and Epigenetics, Center for NeuroMedicine, Brain Science Institute, Korea Institute of Science and Technology, Seoul, South Korea;2. Advanced Analysis Center, Korea Institute of Science and Technology, Seoul, South Korea;3. Alzheimer's Disease Center and Department of Neurology, Boston University School of Medicine, Boston, MA, USA;4. Bedford VA Medical Center, Bedford, MA, USA;5. VA Boston Healthcare System, Boston, MA, USA;6. Department of Integrative Bioscience and Biotechnology, Sejong University, Seoul, South Korea;7. Department of Biochemistry, Yonsei University College of Medicine, Seoul, South Korea;8. Departments of Biochemistry and Biomedical Sciences, Seoul National University College of Medicine, Seoul, South Korea |
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| Abstract: | Alzheimer's disease (AD) is the leading cause of dementia in the elderly. Despite decades of study, effective treatments for AD are lacking. Mitochondrial dysfunction has been closely linked to the pathogenesis of AD, but the relationship between mitochondrial pathology and neuronal damage is poorly understood. Sirtuins (SIRT, silent mating type information regulation 2 homolog in yeast) are NAD‐dependent histone deacetylases involved in aging and longevity. The objective of this study was to investigate the relationship between SIRT3 and mitochondrial function and neuronal activity in AD. SIRT3 mRNA and protein levels were significantly decreased in AD cerebral cortex, and Ac‐p53 K320 was significantly increased in AD mitochondria. SIRT3 prevented p53‐induced mitochondrial dysfunction and neuronal damage in a deacetylase activity‐dependent manner. Notably, mitochondrially targeted p53 (mito‐p53) directly reduced mitochondria DNA‐encoded ND2 and ND4 gene expression resulting in increased reactive oxygen species (ROS) and reduced mitochondrial oxygen consumption. ND2 and ND4 gene expressions were significantly decreased in patients with AD. p53‐ChIP analysis verified the presence of p53‐binding elements in the human mitochondrial genome and increased p53 occupancy of mitochondrial DNA in AD. SIRT3 overexpression restored the expression of ND2 and ND4 and improved mitochondrial oxygen consumption by repressing mito‐p53 activity. Our results indicate that SIRT3 dysfunction leads to p53‐mediated mitochondrial and neuronal damage in AD. Therapeutic modulation of SIRT3 activity may ameliorate mitochondrial pathology and neurodegeneration in AD. |
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| Keywords: | Alzheimer's disease gene expression mitochondria p53 SIRT3 |
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