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Kumar KK, Aburawi EH, Ljubisavljevic M, Leow MKS, Feng X, Ansari SA, Emerald BS. Exploring histone deacetylases in type 2 diabetes mellitus: pathophysiological insights and therapeutic avenues. Clin Epigenetics 2024; 16:78. [PMID: 38862980 PMCID: PMC11167878 DOI: 10.1186/s13148-024-01692-0] [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: 02/27/2024] [Accepted: 06/04/2024] [Indexed: 06/13/2024] Open
Abstract
Diabetes mellitus is a chronic disease that impairs metabolism, and its prevalence has reached an epidemic proportion globally. Most people affected are with type 2 diabetes mellitus (T2DM), which is caused by a decline in the numbers or functioning of pancreatic endocrine islet cells, specifically the β-cells that release insulin in sufficient quantity to overcome any insulin resistance of the metabolic tissues. Genetic and epigenetic factors have been implicated as the main contributors to the T2DM. Epigenetic modifiers, histone deacetylases (HDACs), are enzymes that remove acetyl groups from histones and play an important role in a variety of molecular processes, including pancreatic cell destiny, insulin release, insulin production, insulin signalling, and glucose metabolism. HDACs also govern other regulatory processes related to diabetes, such as oxidative stress, inflammation, apoptosis, and fibrosis, revealed by network and functional analysis. This review explains the current understanding of the function of HDACs in diabetic pathophysiology, the inhibitory role of various HDAC inhibitors (HDACi), and their functional importance as biomarkers and possible therapeutic targets for T2DM. While their role in T2DM is still emerging, a better understanding of the role of HDACi may be relevant in improving insulin sensitivity, protecting β-cells and reducing T2DM-associated complications, among others.
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Affiliation(s)
- Kukkala Kiran Kumar
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 15551, Al Ain, Abu Dhabi, United Arab Emirates
| | - Elhadi Husein Aburawi
- Department of Pediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
| | - Milos Ljubisavljevic
- Department of Physiology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
- Duke-NUS Medical School, Cardiovascular and Metabolic Disorders Program, Singapore, Singapore
| | - Melvin Khee Shing Leow
- LKC School of Medicine, Nanyang Technological University, Singapore, Singapore
- Dept of Endocrinology, Tan Tock Seng Hospital, Singapore, Singapore
- Duke-NUS Medical School, Cardiovascular and Metabolic Disorders Program, Singapore, Singapore
| | - Xu Feng
- Department of Biochemistry, YLL School of Medicine, National University of Singapore, Singapore, Singapore
| | - Suraiya Anjum Ansari
- Department of Biochemistry, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain, Abu Dhabi, United Arab Emirates
- Zayed Center for Health Sciences, United Arab Emirates University, Abu Dhabi, United Arab Emirates
- ASPIRE Precision Medicine Research Institute, Abu Dhabi, United Arab Emirates
| | - Bright Starling Emerald
- Department of Anatomy, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 15551, Al Ain, Abu Dhabi, United Arab Emirates.
- Zayed Center for Health Sciences, United Arab Emirates University, Abu Dhabi, United Arab Emirates.
- ASPIRE Precision Medicine Research Institute, Abu Dhabi, United Arab Emirates.
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2
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Ayilam Ramachandran R, Sanches JM, Robertson DM. The roles of autophagy and mitophagy in corneal pathology: current knowledge and future perspectives. Front Med (Lausanne) 2023; 10:1064938. [PMID: 37153108 PMCID: PMC10160402 DOI: 10.3389/fmed.2023.1064938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 01/16/2023] [Indexed: 05/09/2023] Open
Abstract
The cornea is the clear dome that covers the front portion of the globe. The primary functions of the cornea are to promote the refraction of light and to protect the eye from invading pathogens, both of which are essential for the preservation of vision. Homeostasis of each cellular layer of the cornea requires the orchestration of multiple processes, including the ability to respond to stress. One mechanism whereby cells respond to stress is autophagy, or the process of "self-eating." Autophagy functions to clear damaged proteins and organelles. During nutrient deprivation, amino acids released from protein breakdown via autophagy are used as a fuel source. Mitophagy, a selective form of autophagy, functions to clear damaged mitochondria. Thus, autophagy and mitophagy are important intracellular degradative processes that sustain tissue homeostasis. Importantly, the inhibition or excessive activation of these processes result in deleterious effects on the cell. In the eye, impairment or inhibition of these mechanisms have been associated with corneal disease, degenerations, and dystrophies. This review summarizes the current body of knowledge on autophagy and mitophagy at all layers in the cornea in both non-infectious and infectious corneal disease, dystrophies, and degenerations. It further highlights the critical gaps in our understanding of mitochondrial dysfunction, with implications for novel therapeutics in clinical practice.
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Affiliation(s)
| | - Jose Marcos Sanches
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Danielle M Robertson
- Department of Ophthalmology, The University of Texas Southwestern Medical Center, Dallas, TX, United States
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3
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Yang H, Chen J, Chen Y, Jiang Y, Ge B, Hong L. Sirt1 activation negatively regulates overt apoptosis in Mtb-infected macrophage through Bax. Int Immunopharmacol 2021; 91:107283. [PMID: 33373810 DOI: 10.1016/j.intimp.2020.107283] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 11/25/2020] [Accepted: 12/04/2020] [Indexed: 01/18/2023]
Abstract
Apoptotic pathways play an important role in Mycobacterium tuberculosis-infected macrophages. Sirt1 is a member of the deacetylase family that is known to promote apoptosis resistance in many mammalian cells. However, the apoptotic role of Sirt1 in the process of M. tuberculosis infection remains unclear. With the help of mouse macrophage samples, 129/Sv background mice, and PBMCs-derived macrophages from healthy controls and patients with tuberculosis, we have shown that M. tuberculosis infection reduced Sirt1 mRNA and protein expression, however, increased Bax mRNA and protein expression. Further, we found that resveratrol, a Sirt1 activator, inhibited M. tuberculosis-induced Bax expression. Thus, it seems that Sirt1 acts as a novel regulator of apoptosis signaling in M. tuberculosis infection via its effects on Bax. Sirt1 activation may therefore be a new candidate for the prevention and treatment of tuberculosis.
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Affiliation(s)
- Hong Yang
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai 200092, China; Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China.
| | - Jianxia Chen
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Yanghaoyu Chen
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Yan Jiang
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Baoxue Ge
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai 200092, China; Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, China
| | - Ling Hong
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai 201204, China.
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4
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Wang Z, Guo W, Yi F, Zhou T, Li X, Feng Y, Guo Q, Xu H, Song X, Cao L. The Regulatory Effect of SIRT1 on Extracellular Microenvironment Remodeling. Int J Biol Sci 2021; 17:89-96. [PMID: 33390835 PMCID: PMC7757024 DOI: 10.7150/ijbs.52619] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Accepted: 10/22/2020] [Indexed: 12/12/2022] Open
Abstract
The sirtuins family is well known by its unique nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase function. The most-investigated member of the family, Sirtuin 1 (SIRT1), accounts for deacetylating a broad range of transcription factors and coregulators, such as p53, the Forkhead box O (FOXO), and so on. It serves as a pivotal regulator in various intracellular biological processes, including energy metabolism, DNA damage response, genome stability maintenance and tumorigenesis. Although the most attention has been focused on its intracellular functions, the regulatory effect on extracellular microenvironment remodeling of SIRT1 has been recognized by researchers recently. SIRT1 can regulate cell secretion process and participate in glucose metabolism, neuroendocrine function, inflammation and tumorigenesis. Here, we review the advances in the understanding of SIRT1 on remodeling the extracellular microenvironment, which may provide new ideas for pathogenesis investigation and guidance for clinical treatment.
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Affiliation(s)
- Zhuo Wang
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Wendong Guo
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Fei Yi
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Tingting Zhou
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Xiaoman Li
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Yanling Feng
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Qiqiang Guo
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Hongde Xu
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Xiaoyu Song
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
| | - Liu Cao
- College of Basic Medical Science, Institute of Translational Medicine, Key Laboratory of Medical Cell Biology, Ministry of Education, Key Laboratory of Liaoning Province, China Medical University, Shenyang, Liaoning Province, P.R. China, 110122
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5
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Yang H, Chen J, Chen Y, Jiang Y, Ge B, Hong L. Sirtuin inhibits M. tuberculosis -induced apoptosis in macrophage through glycogen synthase kinase-3β. Arch Biochem Biophys 2020; 694:108612. [PMID: 33007281 DOI: 10.1016/j.abb.2020.108612] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/05/2020] [Accepted: 09/27/2020] [Indexed: 12/22/2022]
Abstract
Apoptotic and inflammatory pathways play important roles in Mycobacterium tuberculosis-infected macrophages. Sirt1 is a member of the deacetylase family that is known to promote apoptosis resistance in mammalian cells and was recently reported to regulate mycobacterial immunopathogenesis via inflammatory responses. However, the apoptotic role of Sirt1 in the process of M. tuberculosis infection remains unclear. With the help of mouse peritoneal macrophage samples, we have shown that resveratrol, a Sirt1 activator, inhibited M. tuberculosis-induced apoptosis in peritoneal macrophages. Further, we found that Sirt1 activation prompted M. tuberculosis induced GSK3β phosphorylation. Further investigation into the possible mechanisms of action showed that Sirt1 directly interacted with GSK3β and enhanced GSK3β phosphorylation by promoting its deacetylation. Sirt1 activation inhibited M. tuberculosis growth. Thus, it seemed that Sirt1 acted as a novel regulator of apoptosis signaling in M. tuberculosis infection via its direct effects on GSK3β. Sirt1 may therefore be a new candidate for the prevention and treatment of tuberculosis.
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Affiliation(s)
- Hong Yang
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, 200092, China; Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China.
| | - Jianxia Chen
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Yanghaoyu Chen
- Department of Pathology, Immunology, and Laboratory Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Yan Jiang
- Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Baoxue Ge
- Department of Microbiology and Immunology, Tongji University School of Medicine, Shanghai, 200092, China; Clinical Translational Research Center, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China; Shanghai TB Key Laboratory, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China
| | - Ling Hong
- Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 201204, China.
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6
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Cheng Y, Liu J, Luan Y, Liu Z, Lai H, Zhong W, Yang Y, Yu H, Feng N, Wang H, Huang R, He Z, Yan M, Zhang F, Sun YG, Ying H, Guo F, Zhai Q. Sarm1 Gene Deficiency Attenuates Diabetic Peripheral Neuropathy in Mice. Diabetes 2019; 68:2120-2130. [PMID: 31439642 PMCID: PMC6804630 DOI: 10.2337/db18-1233] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 08/15/2019] [Indexed: 12/29/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is the most common complication in both type 1 and type 2 diabetes, but any treatment toward the development of DPN is not yet available. Axon degeneration is an early feature of many peripheral neuropathies, including DPN. Delay of axon degeneration has beneficial effects on various neurodegenerative diseases, but its effect on DPN is yet to be elucidated. Deficiency of Sarm1 significantly attenuates axon degeneration in several models, but the effect of Sarm1 deficiency on DPN is still unclear. In this study, we show that Sarm1 knockout mice exhibit normal glucose metabolism and pain sensitivity, and deletion of the Sarm1 gene alleviates hypoalgesia in streptozotocin-induced diabetic mice. Moreover, Sarm1 gene deficiency attenuates intraepidermal nerve fiber loss in footpad skin; alleviates axon degeneration, the change of g-ratio in sciatic nerves, and NAD+ decrease; and relieves axonal outgrowth retardation of dorsal root ganglia from diabetic mice. In addition, Sarm1 gene deficiency markedly diminishes the changes of gene expression profile induced by streptozotocin in the sciatic nerve, especially some abundant genes involved in neurodegenerative diseases. These findings demonstrate that Sarm1 gene deficiency attenuates DPN in mice and suggest that slowing down axon degeneration is a potential promising strategy to combat DPN.
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Affiliation(s)
- Yalan Cheng
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jun Liu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yi Luan
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhiyuan Liu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hejin Lai
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Wuling Zhong
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yale Yang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Huimin Yu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Ning Feng
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hui Wang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rui Huang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Zhishui He
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Menghong Yan
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Fang Zhang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yan-Gang Sun
- Institute of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Hao Ying
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Feifan Guo
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Qiwei Zhai
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, CAS Center for Excellence in Molecular Cell Sciences, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
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7
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Zhu L, Titone R, Robertson DM. The impact of hyperglycemia on the corneal epithelium: Molecular mechanisms and insight. Ocul Surf 2019; 17:644-654. [PMID: 31238114 DOI: 10.1016/j.jtos.2019.06.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 06/11/2019] [Accepted: 06/21/2019] [Indexed: 12/15/2022]
Abstract
Type 2 Diabetes Mellitus (T2DM) is reaching epidemic levels worldwide and with it, there is a significant increase in complications associated with the disease. T2DM affects virtually all organ systems including the eye. While frequently overlooked, diabetic keratopathy is the most common ocular complication of diabetes and can manifest in mild to severe forms, the latter of which poses a major threat to vision. As the initial barrier between the environment and the eye, the corneal epithelium functions in innate immune defense. Compromise of this barrier may predispose the cornea to infection and can hinder the refractive capabilities of the eye. The clinical burden in patients with diabetic keratopathy lies primarily in the inability of the corneal epithelium to repair damage and maintain its tight barrier function. Current therapies for diabetic keratopathy are supportive, centering on the prevention of infection and promotion of an optimal healing environment. With no clear disease-modifying agent identified as of yet, a thorough understanding of the pathophysiology that underlies the development of diabetic keratopathy at the cellular level is critical to identify and develop potential therapeutic agents capable of promoting corneal re-epithelialization to accelerate the wound healing process. The focus of this review is to examine what is known regarding the cellular and molecular mechanisms needed to maintain epithelial homeostasis and how it goes awry in diabetes.
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Affiliation(s)
- Luke Zhu
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Rossella Titone
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States
| | - Danielle M Robertson
- Department of Ophthalmology, University of Texas Southwestern Medical Center, United States.
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8
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Son MJ, Ryu JS, Kim JY, Kwon Y, Chung KS, Mun SJ, Cho YS. Upregulation of mitochondrial NAD + levels impairs the clonogenicity of SSEA1 + glioblastoma tumor-initiating cells. Exp Mol Med 2017; 49:e344. [PMID: 28604662 PMCID: PMC5519015 DOI: 10.1038/emm.2017.74] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/09/2017] [Accepted: 01/31/2017] [Indexed: 02/07/2023] Open
Abstract
Emerging evidence has emphasized the importance of cancer therapies targeting an abnormal metabolic state of tumor-initiating cells (TICs) in which they retain stem cell-like phenotypes and nicotinamide adenine dinucleotide (NAD+) metabolism. However, the functional role of NAD+ metabolism in regulating the characteristics of TICs is not known. In this study, we provide evidence that the mitochondrial NAD+ levels affect the characteristics of glioma-driven SSEA1+ TICs, including clonogenic growth potential. An increase in the mitochondrial NAD+ levels by the overexpression of the mitochondrial enzyme nicotinamide nucleotide transhydrogenase (NNT) significantly suppressed the sphere-forming ability and induced differentiation of TICs, suggesting a loss of the characteristics of TICs. In addition, increased SIRT3 activity and reduced lactate production, which are mainly observed in healthy and young cells, appeared following NNT-overexpressed TICs. Moreover, in vivo tumorigenic potential was substantially abolished by NNT overexpression. Conversely, the short interfering RNA-mediated knockdown of NNT facilitated the maintenance of TIC characteristics, as evidenced by the increased numbers of large tumor spheres and in vivo tumorigenic potential. Our results demonstrated that targeting the maintenance of healthy mitochondria with increased mitochondrial NAD+ levels and SIRT3 activity could be a promising strategy for abolishing the development of TICs as a new therapeutic approach to treating aging-associated tumors.
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Affiliation(s)
- Myung Jin Son
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Jae-Sung Ryu
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Jae Yun Kim
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Stem Cell Research Laboratory, Immunotherapy Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Youjeong Kwon
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Kyung-Sook Chung
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Biomedical Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
| | - Seon Ju Mun
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Stem Cell Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon, Korea
| | - Yee Sook Cho
- Department of Functional Genomics, Korea University of Science & Technology (UST), Daejeon, Korea
- Stem Cell Research Laboratory, Immunotherapy Convergence Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea
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9
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Williams PA, Harder JM, Foxworth NE, Cardozo BH, Cochran KE, John SWM. Nicotinamide and WLD S Act Together to Prevent Neurodegeneration in Glaucoma. Front Neurosci 2017; 11:232. [PMID: 28487632 PMCID: PMC5403885 DOI: 10.3389/fnins.2017.00232] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/07/2017] [Indexed: 01/09/2023] Open
Abstract
Glaucoma is a complex neurodegenerative disease characterized by progressive visual dysfunction leading to vision loss. Retinal ganglion cells are the primary affected neuronal population, with a critical insult damaging their axons in the optic nerve head. This insult is typically secondary to harmfully high levels of intraocular pressure (IOP). We have previously determined that early mitochondrial abnormalities within retinal ganglion cells lead to neuronal dysfunction, with age-related declines in NAD (NAD+ and NADH) rendering retinal ganglion cell mitochondria vulnerable to IOP-dependent stresses. The Wallerian degeneration slow allele, WldS, decreases the vulnerability of retinal ganglion cells in eyes with elevated IOP, but the exact mechanism(s) of protection from glaucoma are not determined. Here, we demonstrate that WldS increases retinal NAD levels. Coupled with nicotinamide administration (an NAD precursor), it robustly protects from glaucomatous neurodegeneration in a mouse model of glaucoma (94% of eyes having no glaucoma, more than WldS or nicotinamide alone). Importantly, nicotinamide and WldS protect somal, synaptic, and axonal compartments, prevent loss of anterograde axoplasmic transport, and protect from visual dysfunction as assessed by pattern electroretinogram. Boosting NAD production generally benefits major compartments of retinal ganglion cells, and may be of value in other complex, age-related, axonopathies where multiple neuronal compartments are ultimately affected.
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Affiliation(s)
- Pete A Williams
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA
| | - Jeffrey M Harder
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA
| | - Nicole E Foxworth
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA
| | - Brynn H Cardozo
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA
| | - Kelly E Cochran
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA
| | - Simon W M John
- The Jackson Laboratory, Howard Hughes Medical InstituteBar Harbor, ME, USA.,Department of Ophthalmology, Tufts University of MedicineBoston, MA, USA
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10
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Mundinger TO, Cooper E, Coleman MP, Taborsky GJ. Short-term diabetic hyperglycemia suppresses celiac ganglia neurotransmission, thereby impairing sympathetically mediated glucagon responses. Am J Physiol Endocrinol Metab 2015; 309:E246-55. [PMID: 26037249 PMCID: PMC4525110 DOI: 10.1152/ajpendo.00140.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/25/2015] [Indexed: 01/09/2023]
Abstract
Short-term hyperglycemia suppresses superior cervical ganglia neurotransmission. If this ganglionic dysfunction also occurs in the islet sympathetic pathway, sympathetically mediated glucagon responses could be impaired. Our objectives were 1) to test for a suppressive effect of 7 days of streptozotocin (STZ) diabetes on celiac ganglia (CG) activation and on neurotransmitter and glucagon responses to preganglionic nerve stimulation, 2) to isolate the defect in the islet sympathetic pathway to the CG itself, and 3) to test for a protective effect of the WLD(S) mutation. We injected saline or nicotine in nondiabetic and STZ-diabetic rats and measured fos mRNA levels in whole CG. We electrically stimulated the preganglionic or postganglionic nerve trunk of the CG in nondiabetic and STZ-diabetic rats and measured portal venous norepinephrine and glucagon responses. We repeated the nicotine and preganglionic nerve stimulation studies in nondiabetic and STZ-diabetic WLD(S) rats. In STZ-diabetic rats, the CG fos response to nicotine was suppressed, and the norepinephrine and glucagon responses to preganglionic nerve stimulation were impaired. In contrast, the norepinephrine and glucagon responses to postganglionic nerve stimulation were normal. The CG fos response to nicotine, and the norepinephrine and glucagon responses to preganglionic nerve stimulation, were normal in STZ-diabetic WLD(S) rats. In conclusion, short-term hyperglycemia's suppressive effect on nicotinic acetylcholine receptors of the CG impairs sympathetically mediated glucagon responses. WLD(S) rats are protected from this dysfunction. The implication is that this CG dysfunction may contribute to the impaired glucagon response to insulin-induced hypoglycemia seen early in type 1 diabetes.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 1/blood
- Diabetes Mellitus, Type 1/complications
- Diabetes Mellitus, Type 1/metabolism
- Diabetes Mellitus, Type 1/physiopathology
- Down-Regulation/drug effects
- Electric Stimulation
- Ganglia, Sympathetic/drug effects
- Ganglia, Sympathetic/metabolism
- Ganglia, Sympathetic/physiopathology
- Ganglionic Stimulants/pharmacology
- Glucagon/blood
- Glucagon/metabolism
- Hyperglycemia/etiology
- Islets of Langerhans/drug effects
- Islets of Langerhans/innervation
- Islets of Langerhans/metabolism
- Male
- Mutant Proteins/metabolism
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neurons/drug effects
- Neurons/metabolism
- Nicotinic Agonists/pharmacology
- Norepinephrine/blood
- Norepinephrine/metabolism
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-fos/metabolism
- Rats, Sprague-Dawley
- Rats, Transgenic
- Rats, Wistar
- Receptors, Nicotinic/chemistry
- Receptors, Nicotinic/metabolism
- Synaptic Transmission/drug effects
- Wallerian Degeneration/complications
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Affiliation(s)
| | - Ellis Cooper
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Michael P Coleman
- The Babraham Institute, Babraham Research Campus, Babraham, Cambridge, United Kingdom; and
| | - Gerald J Taborsky
- Department of Medicine, University of Washington, Seattle, Washington; Veterans Affairs Puget Sound Health Care System, Seattle, Washington
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11
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Cantó C, Menzies KJ, Auwerx J. NAD(+) Metabolism and the Control of Energy Homeostasis: A Balancing Act between Mitochondria and the Nucleus. Cell Metab 2015; 22:31-53. [PMID: 26118927 PMCID: PMC4487780 DOI: 10.1016/j.cmet.2015.05.023] [Citation(s) in RCA: 1034] [Impact Index Per Article: 114.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
NAD(+) has emerged as a vital cofactor that can rewire metabolism, activate sirtuins, and maintain mitochondrial fitness through mechanisms such as the mitochondrial unfolded protein response. This improved understanding of NAD(+) metabolism revived interest in NAD(+)-boosting strategies to manage a wide spectrum of diseases, ranging from diabetes to cancer. In this review, we summarize how NAD(+) metabolism links energy status with adaptive cellular and organismal responses and how this knowledge can be therapeutically exploited.
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Affiliation(s)
- Carles Cantó
- Nestlé Institute of Health Sciences, 1015 Lausanne, Switzerland
| | - Keir J Menzies
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
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12
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Cashman CR, Höke A. Mechanisms of distal axonal degeneration in peripheral neuropathies. Neurosci Lett 2015; 596:33-50. [PMID: 25617478 PMCID: PMC4428955 DOI: 10.1016/j.neulet.2015.01.048] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/16/2015] [Accepted: 01/19/2015] [Indexed: 02/08/2023]
Abstract
Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wld(S)) and Sarm knockout animal models. These studies have shown axonal degeneration to occur through a programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration.
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Affiliation(s)
- Christopher R Cashman
- Departments of Neuroscience and Neurology, USA; MSTP- MD/PhD Program, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Ahmet Höke
- Departments of Neuroscience and Neurology, USA.
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13
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Wallerian degeneration: an emerging axon death pathway linking injury and disease. Nat Rev Neurosci 2014; 15:394-409. [DOI: 10.1038/nrn3680] [Citation(s) in RCA: 387] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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14
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Zhu S, Yang Y, Hu J, Qian L, Jiang Y, Li X, Yang Q, Bai H, Chen Q. Wld(S) ameliorates renal injury in a type 1 diabetic mouse model. Am J Physiol Renal Physiol 2014; 306:F1348-56. [PMID: 24598800 DOI: 10.1152/ajprenal.00418.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease worldwide. The purpose of this study is to investigate whether the Wld(S) (slow Wallerian degeneration; also known as Wld) gene plays a renoprotective role during the progression of DN. Diabetes was induced in 8-wk-old male wild-type (WT) and C57BL/Wld(S) mice by streptozotocin (STZ) injection. Blood and urinary variables including blood glucose, glycated hemoglobin (GHb), insulin, urea nitrogen, and albumin/creatinine ratio were assessed 4, 7, and 14 wk after STZ injection. Periodic acid-Schiff staining, Masson staining, and silver staining were performed for renal pathological analyses. In addition, the renal ultrastructure was observed by electron microscope. The activities of p38 and ERK signaling in renal cortical tissues were evaluated by Western blotting. NAD(+)/NADH ratio and NADPH oxidase activity were also measured. Moreover, the expressions of TNF-α, IL-1, and IL-6 were examined. We provide experimental evidence demonstrating that the Wld(S) gene is expressed in kidney cells and protects against the early stage of diabetes-induced renal dysfunction and extracellular matrix accumulation through delaying the reduction of the NAD(+)/NADH ratio, inhibiting the activation of p38 and ERK signaling, and suppressing oxidative stress as evidenced by the decreased NADPH oxidase activity and lower expression of TNF-α, IL-1, and IL-6.
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Affiliation(s)
- Shuaishuai Zhu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yelin Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Jin Hu
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Lingling Qian
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Yuchen Jiang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Xiaoyu Li
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qing Yang
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Hui Bai
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
| | - Qi Chen
- Atherosclerosis Research Centre, Nanjing Medical University, Nanjing, People's Republic of China
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15
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Fiorino E, Giudici M, Ferrari A, Mitro N, Caruso D, De Fabiani E, Crestani M. The sirtuin class of histone deacetylases: regulation and roles in lipid metabolism. IUBMB Life 2014; 66:89-99. [PMID: 24488813 DOI: 10.1002/iub.1246] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 01/19/2014] [Indexed: 01/05/2023]
Abstract
After the completion of the human genome sequence and that from many other organisms, last decade has witnessed a spectacular gain of knowledge on gene functions. These studies provided new insights on the roles of genes in physiology and disease. Nonetheless, the availability of genetically modified models and of "omics" technologies such as next generation sequencing unveiled clear evidences on epigenetic regulation of many cellular functions. At this regard, sirtuins, belonging to class III histone deacetylase family, have emerged as regulators of metabolism as well as other cellular processes and seem ideally suited as targets of future therapeutical interventions. This review deals on general aspects of the biology of sirtuins and focuses on their relevance in lipid metabolism in different tissues, pointing to their exploitation as potential pharmacological targets of compounds that could be used as new therapeutic alternatives in several disorders ranging from type 2 diabetes and obesity to age-related cardiovascular and neurodegenerative diseases.
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Affiliation(s)
- Erika Fiorino
- Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italia
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16
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Boutant M, Cantó C. SIRT1 metabolic actions: Integrating recent advances from mouse models. Mol Metab 2013; 3:5-18. [PMID: 24567900 PMCID: PMC3929913 DOI: 10.1016/j.molmet.2013.10.006] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/15/2013] [Accepted: 10/17/2013] [Indexed: 01/07/2023] Open
Abstract
SIRT1 has attracted a lot of interest since it was discovered as a mammalian homolog of Sir2, a protein that influences longevity in yeast. Intensive early research suggested a key role of SIRT1 in mammalian development, metabolic flexibility and oxidative metabolism. However, it is the growing body of transgenic models that are allowing us to clearly define the true range of SIRT1 actions. In this review we aim to summarize the most recent lessons that transgenic animal models have taught us about the role of SIRT1 in mammalian metabolic homeostasis and lifespan.
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Affiliation(s)
- Marie Boutant
- Nestlé Institute of Health Sciences S.A., EPFL campus, Quartier de l'Innovation, Bâtiment G, CH-1015 Lausanne, Switzerland
| | - Carles Cantó
- Nestlé Institute of Health Sciences S.A., EPFL campus, Quartier de l'Innovation, Bâtiment G, CH-1015 Lausanne, Switzerland
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17
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Imai S, Yoshino J. The importance of NAMPT/NAD/SIRT1 in the systemic regulation of metabolism and ageing. Diabetes Obes Metab 2013; 15 Suppl 3:26-33. [PMID: 24003918 PMCID: PMC3819727 DOI: 10.1111/dom.12171] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 06/04/2013] [Indexed: 12/23/2022]
Abstract
Ageing is associated with a variety of pathophysiological changes, including development of insulin resistance, progressive decline in β-cell function and chronic inflammation, all of which affect metabolic homeostasis in response to nutritional and environmental stimuli. SIRT1, the mammalian nicotinamide adenine dinucleotide (NAD)-dependent protein deacetylase, and nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting NAD biosynthetic enzyme, together comprise a novel systemic regulatory network, named the 'NAD World', that orchestrates physiological responses to internal and external perturbations and maintains the robustness of the physiological system in mammals. In the past decade, an accumulating body of evidence has demonstrated that SIRT1 and NAMPT, two essential components in the NAD World, play a critical role in regulating insulin sensitivity and insulin secretion throughout the body. In this article, we will summarize the physiological significance of SIRT1 and NAMPT-mediated NAD biosynthesis in metabolic regulation and discuss the ideas of functional hierarchy and frailty in determining the robustness of the system. We will also discuss the potential of key NAD intermediates as effective nutriceuticals for the prevention and the treatment of age-associated metabolic complications, such as type 2 diabetes.
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Affiliation(s)
- S Imai
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO 63110, USA.
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18
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Viscarra JA, Rodriguez R, Vazquez-Medina JP, Lee A, Tift MS, Tavoni SK, Crocker DE, Ortiz RM. Insulin and GLP-1 infusions demonstrate the onset of adipose-specific insulin resistance in a large fasting mammal: potential glucogenic role for GLP-1. Physiol Rep 2013; 1:e00023. [PMID: 23997935 PMCID: PMC3755502 DOI: 10.1002/phy2.23] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Prolonged food deprivation increases lipid oxidation and utilization, which may contribute to the onset of the insulin resistance associated with fasting. Because insulin resistance promotes the preservation of glucose and oxidation of fat, it has been suggested to be an adaptive response to food deprivation. However, fasting mammals exhibit hypoinsulinemia, suggesting that the insulin resistance-like conditions they experience may actually result from reduced pancreatic sensitivity to glucose/capacity to secrete insulin. To determine whether fasting results in insulin resistance or in pancreatic dysfunction, we infused early- and late-fasted seals (naturally adapted to prolonged fasting) with insulin (0.065 U/kg), and a separate group of late-fasted seals with low (10 pmol/L per kg) or high (100 pmol/L per kg) dosages of glucagon-like peptide-1 (GLP-1) immediately following a glucose bolus (0.5 g/kg), and measured the systemic and cellular responses. Because GLP-1 facilitates glucose-stimulated insulin secretion, these infusions provide a method to assess pancreatic insulin-secreting capacity. Insulin infusions increased the phosphorylation of insulin receptor and Akt in adipose and muscle of early- and late-fasted seals; however, the timing of the signaling response was blunted in adipose of late-fasted seals. Despite the dose-dependent increases in insulin and increased glucose clearance (high dose), both GLP-1 dosages produced increases in plasma cortisol and glucagon, which may have contributed to the glucogenic role of GLP-1. Results suggest that fasting induces adipose-specific insulin resistance in elephant seal pups, while maintaining skeletal muscle insulin sensitivity, and therefore suggests that the onset of insulin resistance in fasting mammals is an evolved response to cope with prolonged food deprivation.
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Affiliation(s)
- Jose A Viscarra
- School of Natural Sciences, University of California, Merced
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19
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Nogueiras R, Habegger KM, Chaudhary N, Finan B, Banks AS, Dietrich MO, Horvath TL, Sinclair DA, Pfluger PT, Tschöp MH. Sirtuin 1 and sirtuin 3: physiological modulators of metabolism. Physiol Rev 2012; 92:1479-514. [PMID: 22811431 DOI: 10.1152/physrev.00022.2011] [Citation(s) in RCA: 496] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The sirtuins are a family of highly conserved NAD(+)-dependent deacetylases that act as cellular sensors to detect energy availability and modulate metabolic processes. Two sirtuins that are central to the control of metabolic processes are mammalian sirtuin 1 (SIRT1) and sirtuin 3 (SIRT3), which are localized to the nucleus and mitochondria, respectively. Both are activated by high NAD(+) levels, a condition caused by low cellular energy status. By deacetylating a variety of proteins that induce catabolic processes while inhibiting anabolic processes, SIRT1 and SIRT3 coordinately increase cellular energy stores and ultimately maintain cellular energy homeostasis. Defects in the pathways controlled by SIRT1 and SIRT3 are known to result in various metabolic disorders. Consequently, activation of sirtuins by genetic or pharmacological means can elicit multiple metabolic benefits that protect mice from diet-induced obesity, type 2 diabetes, and nonalcoholic fatty liver disease.
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Affiliation(s)
- Ruben Nogueiras
- Department of Physiology, School of Medicine-Instituto de Investigaciones Sanitarias, University of Santiago de Compostela, Santiago de Compostela, Spain
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20
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Activation of SIRT1 protects pancreatic β-cells against palmitate-induced dysfunction. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1815-25. [PMID: 22968147 DOI: 10.1016/j.bbadis.2012.08.009] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 08/08/2012] [Accepted: 08/13/2012] [Indexed: 01/23/2023]
Abstract
Sirtuin 1 (SIRT1), a nicotinamide adenosine dinucleotide-dependent histone deacetylase, is an important regulator of energy homeostasis in response to nutrient availability. In pancreatic β-cells, SIRT1 has been shown to up-regulate insulin secretion in response to glucose stimulation. However, the potential roles of SIRT1 in islet β-cells against lipotoxicity remain poorly understood. Here, we demonstrated that SIRT1 mRNA and protein expressions were markedly reduced in the islets isolated from rats infused with 20% Intralipid for 24h. Long-term exposure to 0.4mmol/L palmitate also decreased SIRT1 expression in cultured INS-1 cells and isolated rat islets, which was prevented by 10μmol/L resveratrol, a SIRT1 agonist. In addition, resveratrol improved glucose-stimulated insulin secretion decreased by palmitate, which was abrogated by EX527, a specific SIRT1 inhibitor. Furthermore, inhibition of SIRT1 activity by EX527 or a knockdown of SIRT1 suppressed insulin promoter activity, along with decreased insulin, v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA), and NK6 homeodomain 1 (NKX6.1) mRNA expressions. Activation of SIRT1 by resveratrol or overexpression of SIRT1 antagonized palmitate-inhibited insulin transcriptional activity. SIRT1 overexpression exerted an additive effect on pancreatic and duodenal homeobox 1 (PDX1)-stimulated insulin promoter activity and abolished forkhead box O1 protein (FOXO1)-decreased insulin transcriptional activity. Resveratrol reversed FOXO1 nuclear translocation induced by palmitate. Our findings indicate that SIRT1 protects against palmitate-induced β-cell dysfunction.
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21
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Dong XC. Sirtuin biology and relevance to diabetes treatment. ACTA ACUST UNITED AC 2012; 2:243-257. [PMID: 23024708 DOI: 10.2217/dmt.12.16] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Sirtuins are a group of NAD(+)-dependent enzymes that post-translationally modify histones and other proteins. Among seven mammalian sirtuins, SIRT1 has been the most extensively studied and has been demonstrated to play a critical role in all major metabolic organs and tissues. SIRT1 regulates glucose and lipid homeostasis in the liver, modulates insulin secretion in pancreatic islets, controls insulin sensitivity and glucose uptake in skeletal muscle, increases adiponectin expression in white adipose tissue and controls food intake and energy expenditure in the brain. Recently, SIRT3 has been demonstrated to modulate insulin sensitivity in skeletal muscle and systemic metabolism, and Sirt3-null mice manifest characteristics of metabolic syndrome on a high-fat diet. Thus, it is reasonable to believe that enhancing the activities of SIRT1 and SIRT3 may be beneficial for Type 2 diabetes. Although it is controversial, the SIRT1 activator SRT1720 has been reported to be effective in improving glucose metabolism and insulin sensitivity in animal models. More research needs to be conducted so that we can better understand the physiological functions and molecular mechanisms of sirtuins in order to therapeutically target these enzymes for diabetes treatment.
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Affiliation(s)
- X Charlie Dong
- Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, 635 Barnhill Drive, MS1021D, Indianapolis, IN 46202, USA; Tel.: +1 317 278 1097; ;
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