151
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Pillay Y, Phulukdaree A, Nagiah S, Chuturgoon A. Patulin triggers NRF2-mediated survival mechanisms in kidney cells. Toxicon 2015; 99:1-5. [DOI: 10.1016/j.toxicon.2015.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 03/06/2015] [Accepted: 03/11/2015] [Indexed: 02/06/2023]
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152
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Song CL, Tang H, Ran LK, Ko BCB, Zhang ZZ, Chen X, Ren JH, Tao NN, Li WY, Huang AL, Chen J. Sirtuin 3 inhibits hepatocellular carcinoma growth through the glycogen synthase kinase-3β/BCL2-associated X protein-dependent apoptotic pathway. Oncogene 2015; 35:631-41. [PMID: 25915842 DOI: 10.1038/onc.2015.121] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Revised: 02/10/2015] [Accepted: 03/09/2015] [Indexed: 01/03/2023]
Abstract
SIRT3 is a class III histone deacetylase that has been implicated in a variety of cancers. The role of SIRT3 in hepatocellular carcinoma (HCC) remains elusive. In this study, we found that SIRT3 expression was frequently repressed in HCC and its downregulation was closely associated with tumor grade and size. Ectopic expression of SIRT3 inhibited cell growth and induced apoptosis in HCC cells, whereas depletion of SIRT3 in immortalized hepatocyte promoted cell growth and decreased epirubicin-induced apoptosis. Mechanistic studies revealed that SIRT3 deacetylated and activated glycogen synthase kinase-3β (GSK-3β), which subsequently induced expression and mitochondrial translocation of the pro-apoptotic protein BCL2-associated X protein (Bax) to promote apoptosis. GSK-3β inhibitor or gene silencing of BAX reversed SIRT3-induced growth inhibition and apoptosis. Furthermore, SIRT3 overexpression also suppressed tumor growth in vivo. Together, this study reveals a role of SIRT3/GSK-3β/Bax signaling pathway in the suppression of HCC growth, and also suggests that targeting this pathway may represent a potential therapeutic approach for HCC treatment.
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Affiliation(s)
- C-L Song
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - H Tang
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - L-K Ran
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - B C B Ko
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China.,State Key Laboratory of Chirosciences, The Hong Kong Polytechnic University, Hong Kong, China
| | - Z-Z Zhang
- Department of Infectious Diseases, The Children's Hospital of Chongqing Medical University, Chongqing, China
| | - X Chen
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - J-H Ren
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - N-N Tao
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - W-Y Li
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
| | - A-L Huang
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China.,The Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Zhejiang, China
| | - J Chen
- The Second Affiliated Hospital and the Key Laboratory of Molecular Biology of Infectious Diseases Designated by the Chinese Ministry of Education, Chongqing Medical University, Chongqing, China
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153
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Kleszcz R, Paluszczak J, Baer-Dubowska W. Targeting aberrant cancer metabolism - The role of sirtuins. Pharmacol Rep 2015; 67:1068-80. [PMID: 26481524 DOI: 10.1016/j.pharep.2015.03.021] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 03/27/2015] [Accepted: 03/31/2015] [Indexed: 12/23/2022]
Abstract
Cancer cells, as opposed to normal cells, generate energy by increasing aerobic glycolysis, which is a phenomenon called "the Warburg effect". An altered energy metabolism supporting continuous cell growth and proliferation was pointed to as the new "hallmark" of cancer cells. Several hypotheses have been proposed to explain the maintenance of this seemingly wasteful catabolic state. The epigenetic mechanisms which depend on the covalent modifications of both DNA and histones have recently emerged as important players in the regulation of glucose metabolism. The sirtuin family of histone deacetylases has emerged as important regulators of diverse physiological and pathological events, including cancer metabolism. Sirtuins 1-7 (SIRT1-7) belong to class III of histone deacetylase enzymes which are dependent on NAD(+) for activity. It was recently demonstrated that SIRT6 is a tumor suppressor that modulates aerobic glycolysis by repressing HIF1 transcription. Members of this family of enzymes are considered promising pharmaceutical targets for cancer treatment. This review highlights the major functions of sirtuins in relation to cancer metabolism and the possibilities of their activation and inhibition by small molecule drugs.
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Affiliation(s)
- Robert Kleszcz
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, Poznań, Poland
| | - Jarosław Paluszczak
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, Poznań, Poland
| | - Wanda Baer-Dubowska
- Department of Pharmaceutical Biochemistry, Poznan University of Medical Sciences, Poznań, Poland.
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154
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Diebold I, Hennigs JK, Miyagawa K, Li CG, Nickel NP, Kaschwich M, Cao A, Wang L, Reddy S, Chen PI, Nakahira K, Alcazar MAA, Hopper RK, Ji L, Feldman BJ, Rabinovitch M. BMPR2 preserves mitochondrial function and DNA during reoxygenation to promote endothelial cell survival and reverse pulmonary hypertension. Cell Metab 2015; 21:596-608. [PMID: 25863249 PMCID: PMC4394191 DOI: 10.1016/j.cmet.2015.03.010] [Citation(s) in RCA: 163] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 12/19/2014] [Accepted: 03/19/2015] [Indexed: 01/17/2023]
Abstract
Mitochondrial dysfunction, inflammation, and mutant bone morphogenetic protein receptor 2 (BMPR2) are associated with pulmonary arterial hypertension (PAH), an incurable disease characterized by pulmonary arterial (PA) endothelial cell (EC) apoptosis, decreased microvessels, and occlusive vascular remodeling. We hypothesized that reduced BMPR2 induces PAEC mitochondrial dysfunction, promoting a pro-inflammatory or pro-apoptotic state. Mice with EC deletion of BMPR2 develop hypoxia-induced pulmonary hypertension that, in contrast to non-transgenic littermates, does not reverse upon reoxygenation and is associated with reduced PA microvessels and lung EC p53, PGC1α and TFAM, regulators of mitochondrial biogenesis, and mitochondrial DNA. Decreasing PAEC BMPR2 by siRNA during reoxygenation represses p53, PGC1α, NRF2, TFAM, mitochondrial membrane potential, and ATP and induces mitochondrial DNA deletion and apoptosis. Reducing PAEC BMPR2 in normoxia increases p53, PGC1α, TFAM, mitochondrial membrane potential, ATP production, and glycolysis, and induces mitochondrial fission and a pro-inflammatory state. These features are recapitulated in PAECs from PAH patients with mutant BMPR2.
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Affiliation(s)
- Isabel Diebold
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jan K Hennigs
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kazuya Miyagawa
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Caiyun G Li
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nils P Nickel
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Mark Kaschwich
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aiqin Cao
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lingli Wang
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sushma Reddy
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Pin-I Chen
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kiichi Nakahira
- Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Miguel A Alejandre Alcazar
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rachel K Hopper
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lijuan Ji
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Brian J Feldman
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marlene Rabinovitch
- Department of Pediatrics and Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; The Vera Moulton Wall Center for Pulmonary Vascular Disease, Stanford University School of Medicine, Stanford, CA 94305, USA.
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155
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Parihar P, Solanki I, Mansuri ML, Parihar MS. Mitochondrial sirtuins: emerging roles in metabolic regulations, energy homeostasis and diseases. Exp Gerontol 2014; 61:130-41. [PMID: 25482473 DOI: 10.1016/j.exger.2014.12.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 11/19/2014] [Accepted: 12/03/2014] [Indexed: 12/18/2022]
Abstract
The energy production and metabolic homeostasis are well-orchestrated networks of carbohydrate, lipid and protein metabolism. These metabolic pathways are integrated by a key cytoplasmic organelle, the mitochondria, leading to production of many metabolic intermediates and harvest cellular energy in the form of ATP. Sirtuins are a highly conserved family of proteins that mediate cellular physiology and energy demands in response to metabolic inputs. Mitochondria inhabit three main types of sirtuins classified as Sirt3, Sirt4 and Sirt5. These sirtuins regulate mitochondrial metabolic functions mainly through controlling post-translational modifications of mitochondrial protein. However, the biological mechanism involved in controlling mitochondrial metabolic functions is not well understood at this stage. In this review the current knowledge on how mitochondrial sirtuins govern mitochondrial functions including energy production, metabolism, biogenesis and their involvement in different metabolic pathways are discussed. The identifications of potential pharmacological targets of sirtuins in the mitochondria and the bioactive compounds that target mitochondrial sirtuins will increase our understanding on regulation of mitochondrial metabolism in normal and disease state.
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Affiliation(s)
- Priyanka Parihar
- School of Studies in Zoology & Biotechnology, Vikram University, Ujjain, MP, India
| | - Isha Solanki
- School of Studies in Zoology & Biotechnology, Vikram University, Ujjain, MP, India
| | | | - Mordhwaj S Parihar
- School of Studies in Zoology & Biotechnology, Vikram University, Ujjain, MP, India.
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156
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Exercise-induced neuroprotection of hippocampus in APP/PS1 transgenic mice via upregulation of mitochondrial 8-oxoguanine DNA glycosylase. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2014; 2014:834502. [PMID: 25538817 PMCID: PMC4236906 DOI: 10.1155/2014/834502] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/10/2014] [Indexed: 01/01/2023]
Abstract
Improving mitochondrial function has been proposed as a reasonable therapeutic strategy to reduce amyloid-β (Aβ) load and to modify the progression of Alzheimer's disease (AD). However, the relationship between mitochondrial adaptation and brain neuroprotection caused by physical exercise in AD is poorly understood. This study was undertaken to investigate the effects of long-term treadmill exercise on mitochondrial 8-oxoguanine DNA glycosylase-1 (OGG1) level, mtDNA oxidative damage, and mitochondrial function in the hippocampus of APP/PS1 transgenic mouse model of AD. In the present study, twenty weeks of treadmill training significantly improved the cognitive function and reduced the expression of Aβ-42 in APP/PS1 transgenic (Tg) mice. Training also ameliorated mitochondrial respiratory function by increasing the complexes I, and IV and ATP synthase activities, whereas it attenuated ROS generation and mtDNA oxidative damage in Tg mice. Furthermore, the impaired mitochondrial antioxidant enzymes and mitochondrial OGG1 activities seen in Tg mice were restored with training. Acetylation level of mitochondrial OGG1 and MnSOD was markedly suppressed in Tg mice after exercise training, in parallel with increased level of SIRT3. These findings suggest that exercise training could increase mtDNA repair capacity in the mouse hippocampus, which in turn would result in protection against AD-related mitochondrial dysfunction and phenotypic deterioration.
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157
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Hofer A, Wenz T. Post-translational modification of mitochondria as a novel mode of regulation. Exp Gerontol 2014; 56:202-20. [DOI: 10.1016/j.exger.2014.03.006] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 12/26/2022]
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158
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Wu YT, Wu SB, Wei YH. Roles of sirtuins in the regulation of antioxidant defense and bioenergetic function of mitochondria under oxidative stress. Free Radic Res 2014; 48:1070-84. [DOI: 10.3109/10715762.2014.920956] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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159
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Sirtuin-3 (SIRT3), a therapeutic target with oncogenic and tumor-suppressive function in cancer. Cell Death Dis 2014; 5:e1047. [PMID: 24503539 PMCID: PMC3944233 DOI: 10.1038/cddis.2014.14] [Citation(s) in RCA: 165] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 01/05/2014] [Accepted: 01/07/2014] [Indexed: 02/05/2023]
Abstract
Sirtuin-3 (SIRT3), a major mitochondria NAD+-dependent deacetylase, may target mitochondrial proteins for lysine deacetylation and also regulate cellular functions. And, SIRT3 is an emerging instrumental regulator of the mitochondrial adaptive response to stress, such as metabolic reprogramming and antioxidant defense mechanisms. Accumulating evidence has recently demonstrated that SIRT3 may function as either oncogene or tumor suppressor on influencing cell death by targeting a series of key modulators and their relevant pathways in cancer. Thus, in this review, we present the structure, transcriptional regulation, and posttranslational modifications of SIRT3. Subsequently, we focus on highlighting the Janus role of SIRT3 with oncogenic or tumor-suppressive function in cancer, which may provide more new clues for exploring SIRT3 as a therapeutic target for drug discovery.
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160
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Mitochondrial stress signaling promotes cellular adaptations. Int J Cell Biol 2014; 2014:156020. [PMID: 24587804 PMCID: PMC3920668 DOI: 10.1155/2014/156020] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/11/2013] [Indexed: 01/06/2023] Open
Abstract
Mitochondrial dysfunction has been implicated in the aetiology of many complex diseases, as well as the ageing process. Much of the research on mitochondrial dysfunction has focused on how mitochondrial damage may potentiate pathological phenotypes. The purpose of this review is to draw attention to the less well-studied mechanisms by which the cell adapts to mitochondrial perturbations. This involves communication of stress to the cell and successful induction of quality control responses, which include mitophagy, unfolded protein response, upregulation of antioxidant and DNA repair enzymes, morphological changes, and if all else fails apoptosis. The mitochondrion is an inherently stressful environment and we speculate that dysregulation of stress signaling or an inability to switch on these adaptations during times of mitochondrial stress may underpin mitochondrial dysfunction and hence amount to pathological states over time.
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161
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Ying W. Roles of NAD (+) , PARP-1, and Sirtuins in Cell Death, Ischemic Brain Injury, and Synchrotron Radiation X-Ray-Induced Tissue Injury. SCIENTIFICA 2013; 2013:691251. [PMID: 24386592 PMCID: PMC3872437 DOI: 10.1155/2013/691251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
NAD(+) plays crucial roles in a variety of biological processes including energy metabolism, aging, and calcium homeostasis. Multiple studies have also shown that NAD(+) administration can profoundly decrease oxidative cell death and ischemic brain injury. A number of recent studies have further indicated that NAD(+) administration can decrease ischemic brain damage, traumatic brain damage and synchrotron radiation X-ray-induced tissue injury by such mechanisms as inhibiting inflammation, decreasing autophagy, and reducing DNA damage. Our latest study that applies nano-particles as a NAD(+) carrier has also provided first direct evidence demonstrating a key role of NAD(+) depletion in oxidative stress-induced ATP depletion. Poly(ADP-ribose) polymerase-1 (PARP-1) and sirtuins are key NAD(+)-consuming enzymes that mediate multiple biological processes. Recent studies have provided new information regarding PARP-1 and sirtuins in cell death, ischemic brain damage and synchrotron radiation X-ray-induced tissue damage. These findings have collectively supported the hypothesis that NAD(+) metabolism, PARP-1 and sirtuins play fundamental roles in oxidative stress-induced cell death, ischemic brain injury, and radiation injury. The findings have also supported "the Central Regulatory Network Hypothesis", which proposes that a fundamental network that consists of ATP, NAD(+) and Ca(2+) as its key components is the essential network regulating various biological processes.
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Affiliation(s)
- Weihai Ying
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200032, China
- Department of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
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162
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Pantazi E, Zaouali MA, Bejaoui M, Folch-Puy E, Abdennebi HB, Roselló-Catafau J. Role of sirtuins in ischemia-reperfusion injury. World J Gastroenterol 2013; 19:7594-7602. [PMID: 24616566 PMCID: PMC3837258 DOI: 10.3748/wjg.v19.i43.7594] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 09/16/2013] [Accepted: 09/29/2013] [Indexed: 02/06/2023] Open
Abstract
Ischemia-reperfusion injury (IRI) remains an unresolved and complicated situation in clinical practice, especially in the case of organ transplantation. Several factors contribute to its complexity; the depletion of energy during ischemia and the induction of oxidative stress during reperfusion initiate a cascade of pathways that lead to cell death and finally to severe organ injury. Recently, the sirtuin family of nicotinamide adenine dinucleotide-dependent deacetylases has gained increasing attention from researchers, due to their involvement in the modulation of a wide variety of cellular functions. There are seven mammalian sirtuins and, among them, the nuclear/cytoplasmic sirtuin 1 (SIRT1) and the mitochondrial sirtuin 3 (SIRT3) are ubiquitously expressed in many tissue types. Sirtuins are known to play major roles in protecting against cellular stress and in controlling metabolic pathways, which are key processes during IRI. In this review, we mainly focus on SIRT1 and SIRT3 and examine their role in modulating pathways against energy depletion during ischemia and their involvement in oxidative stress, apoptosis, microcirculatory stress and inflammation during reperfusion. We present evidence of the beneficial effects of sirtuins against IRI and emphasize the importance of developing new strategies by enhancing their action.
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163
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Kincaid B, Bossy-Wetzel E. Forever young: SIRT3 a shield against mitochondrial meltdown, aging, and neurodegeneration. Front Aging Neurosci 2013; 5:48. [PMID: 24046746 PMCID: PMC3764375 DOI: 10.3389/fnagi.2013.00048] [Citation(s) in RCA: 223] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Accepted: 08/21/2013] [Indexed: 12/12/2022] Open
Abstract
Caloric restriction (CR), fasting, and exercise have long been recognized for their neuroprotective and lifespan-extending properties; however, the underlying mechanisms of these phenomena remain elusive. Such extraordinary benefits might be linked to the activation of sirtuins. In mammals, the sirtuin family has seven members (SIRT1–7), which diverge in tissue distribution, subcellular localization, enzymatic activity, and targets. SIRT1, SIRT2, and SIRT3 have deacetylase activity. Their dependence on NAD+ directly links their activity to the metabolic status of the cell. High NAD+ levels convey neuroprotective effects, possibly via activation of sirtuin family members. Mitochondrial sirtuin 3 (SIRT3) has received much attention for its role in metabolism and aging. Specific small nucleotide polymorphisms in Sirt3 are linked to increased human lifespan. SIRT3 mediates the adaptation of increased energy demand during CR, fasting, and exercise to increased production of energy equivalents. SIRT3 deacetylates and activates mitochondrial enzymes involved in fatty acid β-oxidation, amino acid metabolism, the electron transport chain, and antioxidant defenses. As a result, the mitochondrial energy metabolism increases. In addition, SIRT3 prevents apoptosis by lowering reactive oxygen species and inhibiting components of the mitochondrial permeability transition pore. Mitochondrial deficits associated with aging and neurodegeneration might therefore be slowed or even prevented by SIRT3 activation. In addition, upregulating SIRT3 activity by dietary supplementation of sirtuin activating compounds might promote the beneficial effects of this enzyme. The goal of this review is to summarize emerging data supporting a neuroprotective action of SIRT3 against Alzheimer’s disease, Huntington’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Brad Kincaid
- Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida Orlando, FL, USA
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