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Gad H, Mohammed I, Dauleh H, Pasha M, Al-Barazenji T, Hussain K, Malik RA. Case report: Nerve fiber regeneration in children with melanocortin 4 receptor gene mutation related obesity treated with semaglutide. Front Endocrinol (Lausanne) 2024; 15:1385463. [PMID: 38974580 PMCID: PMC11227249 DOI: 10.3389/fendo.2024.1385463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 06/07/2024] [Indexed: 07/09/2024] Open
Abstract
Melanocortin 4 receptor (MC4R) mutations are the commonest cause of monogenic obesity through dysregulation of neuronal pathways in the hypothalamus and prefrontal cortex that regulate hunger and satiety. MC4R also regulates neuropathic pain pathways via JNK signaling after nerve injury. We show evidence of corneal small fiber degeneration in 2 siblings carrying a heterozygous missense variant c.508A>G, p.Ille170Val in the MC4R gene. Both children were treated with once weekly semaglutide for 6 months with no change in weight, and only a minor improvement in HbA1c and lipid profile. However, there was evidence of nerve regeneration with an increase in corneal nerve fiber density (CNFD) [child A (13.9%), child B (14.7%)], corneal nerve branch density (CNBD) [child A (110.2%), child B (58.7%)] and corneal nerve fiber length (CNFL) [child A (21.5%), child B (44.0%)].
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Affiliation(s)
- Hoda Gad
- Research Department, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Idris Mohammed
- Endocrinology Department, Sidra Medicine, Doha, Qatar
- College of Health & Life Sciences, Hamad Bin Khalifa University, Doha, Qatar
| | - Hajar Dauleh
- Endocrinology Department, Sidra Medicine, Doha, Qatar
| | - Maheen Pasha
- Endocrinology Department, Sidra Medicine, Doha, Qatar
| | | | | | - Rayaz A. Malik
- Research Department, Weill Cornell Medicine-Qatar, Doha, Qatar
- Institute of Cardiovascular Medicine, University of Manchester, Manchester, United Kingdom
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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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3
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Teaney NA, Cyr NE. FoxO1 as a tissue-specific therapeutic target for type 2 diabetes. Front Endocrinol (Lausanne) 2023; 14:1286838. [PMID: 37941908 PMCID: PMC10629996 DOI: 10.3389/fendo.2023.1286838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023] Open
Abstract
Forkhead box O (FoxO) proteins are transcription factors that mediate many aspects of physiology and thus have been targeted as therapeutics for several diseases including metabolic disorders such as type 2 diabetes mellitus (T2D). The role of FoxO1 in metabolism has been well studied, but recently FoxO1's potential for diabetes prevention and therapy has been debated. For example, studies have shown that increased FoxO1 activity in certain tissue types contributes to T2D pathology, symptoms, and comorbidities, yet in other tissue types elevated FoxO1 has been reported to alleviate symptoms associated with diabetes. Furthermore, studies have reported opposite effects of active FoxO1 in the same tissue type. For example, in the liver, FoxO1 contributes to T2D by increasing hepatic glucose production. However, FoxO1 has been shown to either increase or decrease hepatic lipogenesis as well as adipogenesis in white adipose tissue. In skeletal muscle, FoxO1 reduces glucose uptake and oxidation, promotes lipid uptake and oxidation, and increases muscle atrophy. While many studies show that FoxO1 lowers pancreatic insulin production and secretion, others show the opposite, especially in response to oxidative stress and inflammation. Elevated FoxO1 in the hypothalamus increases the risk of developing T2D. However, increased FoxO1 may mitigate Alzheimer's disease, a neurodegenerative disease strongly associated with T2D. Conversely, accumulating evidence implicates increased FoxO1 with Parkinson's disease pathogenesis. Here we review FoxO1's actions in T2D conditions in metabolic tissues that abundantly express FoxO1 and highlight some of the current studies targeting FoxO1 for T2D treatment.
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Affiliation(s)
- Nicole A. Teaney
- Stonehill College, Neuroscience Program, Easton, MA, United States
| | - Nicole E. Cyr
- Stonehill College, Neuroscience Program, Easton, MA, United States
- Stonehill College, Department of Biology, Easton, MA, United States
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4
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Antioxidative Potentials of Incretin-Based Medications: A Review of Molecular Mechanisms. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:9959320. [PMID: 34007411 PMCID: PMC8099522 DOI: 10.1155/2021/9959320] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/11/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
Glucagon-like peptide 1 receptor agonists and dipeptidyl-peptidase 4 inhibitors are medications used for managing diabetes, mimicking the metabolic effects of incretin hormones. Recent evidence suggests that these medications have antioxidative potentials in the diabetic milieu. The pathophysiology of most diabetic complications involves oxidative stress. Therefore, if incretin-based antidiabetic medications can alleviate the free radicals involved in oxidative stress, they can potentially provide further therapeutic effects against diabetic complications. However, the molecular mechanisms by which these medications protect against oxidative stress are not fully understood. In the current review, we discuss the potential molecular mechanisms behind these pharmacologic agents' antioxidative properties.
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5
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Maissan P, Mooij EJ, Barberis M. Sirtuins-Mediated System-Level Regulation of Mammalian Tissues at the Interface between Metabolism and Cell Cycle: A Systematic Review. BIOLOGY 2021; 10:194. [PMID: 33806509 PMCID: PMC7999230 DOI: 10.3390/biology10030194] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/20/2021] [Accepted: 02/25/2021] [Indexed: 02/06/2023]
Abstract
Sirtuins are a family of highly conserved NAD+-dependent proteins and this dependency links Sirtuins directly to metabolism. Sirtuins' activity has been shown to extend the lifespan of several organisms and mainly through the post-translational modification of their many target proteins, with deacetylation being the most common modification. The seven mammalian Sirtuins, SIRT1 through SIRT7, have been implicated in regulating physiological responses to metabolism and stress by acting as nutrient sensors, linking environmental and nutrient signals to mammalian metabolic homeostasis. Furthermore, mammalian Sirtuins have been implicated in playing major roles in mammalian pathophysiological conditions such as inflammation, obesity and cancer. Mammalian Sirtuins are expressed heterogeneously among different organs and tissues, and the same holds true for their substrates. Thus, the function of mammalian Sirtuins together with their substrates is expected to vary among tissues. Any therapy depending on Sirtuins could therefore have different local as well as systemic effects. Here, an introduction to processes relevant for the actions of Sirtuins, such as metabolism and cell cycle, will be followed by reasoning on the system-level function of Sirtuins and their substrates in different mammalian tissues. Their involvement in the healthy metabolism and metabolic disorders will be reviewed and critically discussed.
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Affiliation(s)
- Parcival Maissan
- Synthetic Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
| | - Eva J. Mooij
- Systems Biology, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, Surrey, UK;
- Centre for Mathematical and Computational Biology, CMCB, University of Surrey, Guildford GU2 7XH, Surrey, UK
| | - Matteo Barberis
- Synthetic Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH Amsterdam, The Netherlands;
- Systems Biology, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford GU2 7XH, Surrey, UK;
- Centre for Mathematical and Computational Biology, CMCB, University of Surrey, Guildford GU2 7XH, Surrey, UK
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6
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Li XD, He SS, Wan TT, Li YB. Liraglutide protects palmitate-induced INS-1 cell injury by enhancing autophagy mediated via FoxO1. Mol Med Rep 2020; 23:147. [PMID: 33355375 PMCID: PMC7789139 DOI: 10.3892/mmr.2020.11786] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 11/12/2020] [Indexed: 02/06/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by insulin resistance and a progressive loss in mass and function of pancreatic β-cells. In T2DM, lipotoxicity leads to β-cells dysfunction and decreases its number. Autophagy serves a crucial role in maintaining the normal islet architecture and the function of β-cells. Moreover, glucagon-like peptide-1 (GLP-1) and its analogs have beneficial roles in pancreatic β-cells. However, the protective effects of GLP-1 agents on palmitate (PA)-induced pancreatic β-cells and their underlying mechanisms are not fully elucidated. Forkhead box O1 (FoxO1) can prevent pancreatic β-cells from apoptosis. Whether GLP-1 protects against PA-induced β-cells injury via FoxO1 remains unknown. The present study exposed INS-1 cells to PA to establish a T2DM injury model. Cell viability was evaluated using a Cell Counting Kit-8 assay, and apoptosis was determined via western blotting. Furthermore, autophagy was examined using western blotting, immunofluorescence and transmission electron microscopy. Silencing FoxO1 was used to inhibit the activities of FoxO1. The results suggested that the GLP-1 analog liraglutide enhanced the cell viability, inhibited the protein expression of cleaved caspase-3 and increased the expression levels of microtubule-associated protein 1 light chain3 (LC3) II/I, and FoxO1 in INS-1 cells. The autophagy inhibitor chloroquine inhibited the protective effects of liraglutide on INS-1 cells. Silencing of FoxO1 decreased the expression levels of LC3-II and attenuated the protection of liraglutide on the viability of INS-1 cells. In conclusion, the results indicated that liraglutide ameliorated the PA-induced islet β-cells injury via the upregulation of autophagy-mediated by FoxO1.
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Affiliation(s)
- Xiu-Dan Li
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Shan-Shan He
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Ting-Ting Wan
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
| | - Yan-Bo Li
- Department of Endocrinology, First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang 150001, P.R. China
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Chung JY, Jeong JH, Song J. Resveratrol Modulates the Gut-Brain Axis: Focus on Glucagon-Like Peptide-1, 5-HT, and Gut Microbiota. Front Aging Neurosci 2020; 12:588044. [PMID: 33328965 PMCID: PMC7732484 DOI: 10.3389/fnagi.2020.588044] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 10/23/2020] [Indexed: 12/12/2022] Open
Abstract
Resveratrol is a natural polyphenol that has anti-aging and anti-inflammatory properties against stress condition. It is reported that resveratrol has beneficial functions in various metabolic and central nervous system (CNS) diseases, such as obesity, diabetes, depression, and dementia. Recently, many researchers have emphasized the connection between the brain and gut, called the gut-brain axis, for treating both CNS neuropathologies and gastrointestinal diseases. Based on previous findings, resveratrol is involved in glucagon-like peptide 1 (GLP-1) secreted by intestine L cells, the patterns of microbiome in the intestine, the 5-hydroxytryptamine (5-HT) level, and CNS inflammation. Here, we review recent evidences concerning the relevance and regulatory function of resveratrol in the gut-brain axis from various perspectives. Here, we highlight the necessity for further study on resveratrol's specific mechanism in the gut-brain axis. We present the potential of resveratrol as a natural therapeutic substance for treating both neuropathology and gastrointestinal dysfunction.
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Affiliation(s)
- Ji Yeon Chung
- Department of Neurology, Chosun University Medical School, Gwangju, South Korea
| | - Jae-Ho Jeong
- Department of Microbiology, Chonnam National University Medical School, Gwangju, South Korea
| | - Juhyun Song
- Department of Anatomy, Chonnam National University Medical School, Gwangju, South Korea
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8
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Chi ZC. Research status and prgoress of nonalcoholic fatty pancreatic disease. Shijie Huaren Xiaohua Zazhi 2020; 28:933-950. [DOI: 10.11569/wcjd.v28.i19.933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty pancreatic disease (NAFPD) is a disease characterized by an increase in pancreatic fat accumulation. It is a component of the metabolic syndrome and often coexists with nonalcoholic fatty liver disease. Once the diagnosis is established, it is closely related to acute and chronic pancreatitis, type 2 diabetes mellitus, pancreatic fibrosis, and pancreatic cancer. In recent years, it has been confirmed that NAFPD is closely related to cardiovascular disease, liver fibrosis, and liver cancer. The prevalence of NAFPD ranges between 11% and 69%, and increases with age. It is worth noting that the prevalence in obese children is twice as high as that in non-obese children. The high prevalence rate and complexity of the disease have aroused people's high attention. Therefore, to improve the understanding of NAFPD, fully understand the clinical significance of NAFPD, and further study its pathogenesis, diagnosis, and treatment require the collaboration and joint efforts of multiple disciplines, including hepatopathy, gastroenterology, endocrine metabolism, cardiovascular disease, imaging, pathology, and others. In this paper, we review the clinical significance, pathogenesis, and imaging diagnosis of NAFPD and propose our personal understanding of the key points in future research.
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Affiliation(s)
- Zhao-Chun Chi
- Department of Gastroenterology, Qingdao Municipal Hospital, Qingdao 266011, Shandong Province, China
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9
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Jamali-Raeufy N, Barati H, Baluchnejadmojarad T, Roghani M, Goudarzi M. Combination therapy with dipeptidyl peptidase-4 and P2X7 purinoceptor inhibitors gives rise to antiepileptic effects in rats. J Chem Neuroanat 2020; 110:101855. [PMID: 33031915 DOI: 10.1016/j.jchemneu.2020.101855] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/01/2020] [Accepted: 09/04/2020] [Indexed: 01/20/2023]
Abstract
OBJECTIVE(S) Although the available therapeutic agents alleviate the symptoms in patients with temporal lobe epilepsy (TLE), these antiepileptic drugs do not provide adequate control of seizures in 30-40 % of patients. This study was conducted to evaluate anti-epileptic effects of simultaneous inhibition of dipeptidyl peptidase-4 and P2 × 7 purinoceptors in Kainate treated rats. MATERIALS AND METHODS Brilliant Blue G)BBG(, linagliptin)lin(and lin + BBG were administrated 30 min prior to induction of the intrahippocampal kainate model of epilepsy in male Wistar rats. In the case of valproic acid group, the animals intraperitoneally received valproic acid for 7 consecutive days prior to induction of the model. We carried out histological evaluations, monitoring of behavior, recording of intracranial electroencepholography (IEEG), and determination of astrogliosis and DNA fragmentation using ELISA methods. RESULTS Our results showed that BBG and lin combination therapy had better effects on decrease in astrogliosis, DNA fragmentation and cognitive disturbances than ones whereas its effects on neuronal survival and seizure severity was similar to only BBG or lin. Likewise, the effects of lin + BBG on decrease in DNA fragmentation and cognitive disturbances were better than valproic acid group. CONCLUSION Our findings suggest that simultaneous inhibition of dipeptidyl peptidase-4 and P2 × 7 purinoceptors might more efficiently provide protection against progression of the kainate-induced TLE in rats.
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Affiliation(s)
- Nida Jamali-Raeufy
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Hossain Barati
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | | | - Mehrdad Roghani
- Neurophysiology Research Center, Department of Physiology, Shahed University, Tehran, Iran.
| | - Mina Goudarzi
- Department of Physiology, School of Medicine, Iran University of Medical Sciences, Tehran, Iran.
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10
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Curran M, Drayson MT, Andrews RC, Zoppi C, Barlow JP, Solomon TPJ, Narendran P. The benefits of physical exercise for the health of the pancreatic β-cell: a review of the evidence. Exp Physiol 2020; 105:579-589. [PMID: 32012372 DOI: 10.1113/ep088220] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 01/29/2020] [Indexed: 12/15/2022]
Abstract
NEW FINDINGS What is the topic of this review? This review discusses the evidence of the benefits of exercise training for β-cell health through improvements in function, proliferation and survival which may have implications in the treatment of diabetes. What advances does it highlight? This review highlights how exercise may modulate β-cell health in the context of diabetes and highlights the need for further exploration of whether β-cell preserving effects of exercise translates to T1D. ABSTRACT Physical exercise is a core therapy for type 1 and type 2 diabetes. Whilst the benefits of exercise for different physiological systems are recognised, the effect of exercise specifically on the pancreatic β-cell is not well described. Here we review the effects of physical exercise on β-cell health. We show that exercise improves β-cell mass and function. The improved function manifests primarily through the increased insulin content of the β-cell and its increased ability to secrete insulin in response to a glucose stimulus. We review the evidence relating to glucose sensing, insulin signalling, β-cell proliferation and β-cell apoptosis in humans and animal models with acute exercise and following exercise training programmes. Some of the mechanisms through which these benefits manifest are discussed.
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Affiliation(s)
- Michelle Curran
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK.,Functional and Mechanistic Safety, Clinical Pharmacology and Safety Sciences, R&D, AstraZeneca, Cambridge, UK.,Department of Surgery, University of Cambridge, Cambridge, UK
| | - Mark T Drayson
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK
| | | | - Claudio Zoppi
- Department of Structural and Functional Biology, Institute of Biology, University of Campinas (UNICAMP), São Paulo, Brazil
| | - Jonathan P Barlow
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Thomas P J Solomon
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK
| | - Parth Narendran
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, UK.,Department of Diabetes, The Queen Elizabeth Hospital, Birmingham, UK
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11
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Jeon J, Choi S, Ha E, Lee H, Kim T, Han S, Kim H, Kim D, Kang Y, Lee K. GLP‑1 improves palmitate‑induced insulin resistance in human skeletal muscle via SIRT1 activity. Int J Mol Med 2019; 44:1161-1171. [DOI: 10.3892/ijmm.2019.4272] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 07/01/2019] [Indexed: 11/06/2022] Open
Affiliation(s)
- Ja Jeon
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Sung‑E Choi
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Eun Ha
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Han Lee
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Tae Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Seoul Medical Center, Seoul 02076, Republic of Korea
| | - Seung Han
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Hae Kim
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Dae Kim
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
| | - Yup Kang
- Department of Physiology, Ajou University School of Medicine, Suwon 16499, Republic of KoreaDivision of Endocrinology and Metabolism, Department of Internal Medicine, Seoul Medical Center, Seoul 02076, Republic of Korea
| | - Kwan‑Woo Lee
- Department of Endocrinology and Metabolism, Ajou University School of Medicine, Suwon 16499, Republic of Korea
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12
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Singh CK, Chhabra G, Ndiaye MA, Garcia-Peterson LM, Mack NJ, Ahmad N. The Role of Sirtuins in Antioxidant and Redox Signaling. Antioxid Redox Signal 2018; 28:643-661. [PMID: 28891317 PMCID: PMC5824489 DOI: 10.1089/ars.2017.7290] [Citation(s) in RCA: 473] [Impact Index Per Article: 78.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
SIGNIFICANCE Antioxidant and redox signaling (ARS) events are regulated by critical molecules that modulate antioxidants, reactive oxygen species (ROS) or reactive nitrogen species (RNS), and/or oxidative stress within the cell. Imbalances in these molecules can disturb cellular functions to become pathogenic. Sirtuins serve as important regulators of ARS in cells. Recent Advances: Sirtuins (SIRTs 1-7) are a family of nicotinamide adenine dinucleotide (NAD)-dependent histone deacetylases with the ability to deacetylate histone and nonhistone targets. Recent studies show that sirtuins modulate the regulation of a variety of cellular processes associated with ARS. SIRT1, SIRT3, and SIRT5 protect the cell from ROS, and SIRT2, SIRT6, and SIRT7 modulate key oxidative stress genes and mechanisms. Interestingly, SIRT4 has been shown to induce ROS production and has antioxidative roles as well. CRITICAL ISSUES A complete understanding of the roles of sirtuins in redox homeostasis of the cell is very important to understand the normal functioning as well as pathological manifestations. In this review, we have provided a critical discussion on the role of sirtuins in the regulation of ARS. We have also discussed mechanistic interactions among different sirtuins. Indeed, a complete understanding of sirtuin biology could be critical at multiple fronts. FUTURE DIRECTIONS Sirtuins are emerging to be important in normal mammalian physiology and in a variety of oxidative stress-mediated pathological situations. Studies are needed to dissect the mechanisms of sirtuins in maintaining redox homeostasis. Efforts are also required to assess the targetability of sirtuins in the management of redox-regulated diseases. Antioxid. Redox Signal. 28, 643-661.
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Affiliation(s)
- Chandra K Singh
- Department of Dermatology, University of Wisconsin , Madison, Wisconsin
| | - Gagan Chhabra
- Department of Dermatology, University of Wisconsin , Madison, Wisconsin
| | - Mary Ann Ndiaye
- Department of Dermatology, University of Wisconsin , Madison, Wisconsin
| | | | - Nicholas J Mack
- Department of Dermatology, University of Wisconsin , Madison, Wisconsin
| | - Nihal Ahmad
- Department of Dermatology, University of Wisconsin , Madison, Wisconsin
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13
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Ethanol extract of Atractylodis macrocephalae Rhizoma ameliorates insulin resistance and gut microbiota in type 2 diabetic db/db mice. J Funct Foods 2017. [DOI: 10.1016/j.jff.2017.10.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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14
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Moullé VS, Ghislain J, Poitout V. Nutrient regulation of pancreatic β-cell proliferation. Biochimie 2017; 143:10-17. [PMID: 28987628 DOI: 10.1016/j.biochi.2017.09.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 09/28/2017] [Indexed: 12/17/2022]
Abstract
Excess consumption of energy-dense foods combined with a sedentary lifestyle is driving an obesity epidemic. Although obesity is closely associated with insulin resistance, most individuals meet the insulin demand by increasing their functional β-cell mass. Those who eventually develop type 2 diabetes are distinguished by a failure in this compensatory process. Although a causal role of insulin resistance in compensatory β-cell responses has received considerable experimental support, precisely how the β cell senses changes in the metabolic environment is still unknown. As metabolism of glucose, lipids and amino acids is profoundly altered in obesity, it is not surprising that these nutrients are conspicuous among the factors proposed to contribute. In this review we summarise our understanding of the role of nutrients, in particular glucose, fatty acids and amino acids in β-cell compensation with a particular emphasis on their relation to insulin resistance-induced factors and their underlying mechanism of action. Finally, we describe the concept of epigenetic programming and review recent studies illustrating how the status of the β cell epigenome is a product of its nutrient environment, and how metabolic programming of the β cell contributes to diabetes risk.
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Affiliation(s)
- Valentine S Moullé
- Montreal Diabetes Research Center, University of Montreal, QC, Canada; CRCHUM, University of Montreal, QC, Canada.
| | - Julien Ghislain
- Montreal Diabetes Research Center, University of Montreal, QC, Canada; CRCHUM, University of Montreal, QC, Canada.
| | - Vincent Poitout
- Montreal Diabetes Research Center, University of Montreal, QC, Canada; CRCHUM, University of Montreal, QC, Canada; Department of Medicine, University of Montreal, QC, Canada; Department of Biochemistry and Molecular Medicine, University of Montreal, QC, Canada.
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Muhammad AB, Xing B, Liu C, Naji A, Ma X, Simmons RA, Hua X. Menin and PRMT5 suppress GLP1 receptor transcript and PKA-mediated phosphorylation of FOXO1 and CREB. Am J Physiol Endocrinol Metab 2017; 313:E148-E166. [PMID: 28270438 PMCID: PMC5582886 DOI: 10.1152/ajpendo.00241.2016] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 01/11/2017] [Accepted: 02/20/2017] [Indexed: 12/23/2022]
Abstract
Menin is a scaffold protein that interacts with several epigenetic mediators to regulate gene transcription, and suppresses pancreatic β-cell proliferation. Tamoxifen-inducible deletion of multiple endocrine neoplasia type 1 (MEN1) gene, which encodes the protein menin, increases β-cell mass in multiple murine models of diabetes and ameliorates diabetes. Glucagon-like-peptide-1 (GLP1) is another key physiological modulator of β-cell mass and glucose homeostasis. However, it is not clearly understood whether menin crosstalks with GLP1 signaling. Here, we show that menin and protein arginine methyltransferase 5 (PRMT5) suppress GLP1 receptor (GLP1R) transcript levels. Notably, a GLP1R agonist induces phosphorylation of forkhead box protein O1 (FOXO1) at S253, and the phosphorylation is mediated by PKA. Interestingly, menin suppresses GLP1-induced and PKA-mediated phosphorylation of both FOXO1 and cAMP response element binding protein (CREB), likely through a protein arginine methyltransferase. Menin-mediated suppression of FOXO1 and CREB phosphorylation increases FOXO1 levels and suppresses CREB target genes, respectively. A small-molecule menin inhibitor reverses menin-mediated suppression of both FOXO1 and CREB phosphorylation. In addition, ex vivo treatment of both mouse and human pancreatic islets with a menin inhibitor increases levels of proliferation marker Ki67. In conclusion, our results suggest that menin and PRMT5 suppress GLP1R transcript levels and PKA-mediated phosphorylation of FOXO1 and CREB, and a menin inhibitor may reverse this suppression to induce β-cell proliferation.
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Affiliation(s)
- Abdul Bari Muhammad
- Abramson Family Cancer Research Institute, Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Bowen Xing
- Shenzen University School of Medicine, Institute of Diabetes Research, Shenzhen, Guangdong, China
| | - Chengyang Liu
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ali Naji
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xiaosong Ma
- Shenzen University School of Medicine, Institute of Diabetes Research, Shenzhen, Guangdong, China
| | - Rebecca A Simmons
- Department of Pediatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
- Division of Neonatology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Xianxin Hua
- Abramson Family Cancer Research Institute, Department of Cancer Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania;
- Institute for Diabetes, Obesity, and Metabolism Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Purwana I, Liu JJ, Portha B, Buteau J. HSF1 acetylation decreases its transcriptional activity and enhances glucolipotoxicity-induced apoptosis in rat and human beta cells. Diabetologia 2017; 60:1432-1441. [PMID: 28547133 DOI: 10.1007/s00125-017-4310-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Accepted: 04/13/2017] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS Heat shock factor protein 1 (HSF1) is a transcription factor that regulates the expression of key molecular chaperones, thereby orchestrating the cellular response to stress. This system was recently implicated in the control of insulin sensitivity and is therefore being scrutinised as a novel therapeutic avenue for type 2 diabetes. However, the regulation and biological actions of HSF1 in beta cells remain elusive. Herein, we sought to investigate the regulation of HSF1 in pancreatic beta cells and to study its potential role in cell survival. METHODS We exposed human islets and beta cell lines to glucolipotoxicity and thapsigargin. HSF1 activity was evaluated by gel shift assay. HSF1 acetylation and interaction with the protein acetylase cAMP response element binding protein (CBP) were investigated by western blot. We measured the expression of HSF1 and its canonical targets in islets from Goto-Kakizaki (GK) rat models of diabetes and delineated the effects of HSF1 acetylation using mutants mimicking constitutive acetylation and deacetylation of the protein. RESULTS Glucolipotoxicity promoted HSF1 acetylation and interaction with CBP. Glucolipotoxicity-induced HSF1 acetylation inhibited HSF1 DNA binding activity and decreased the expression of its target genes. Restoration of HSF1 activity in beta cells prevented glucolipotoxicity-induced endoplasmic reticulum stress and apoptosis. However, overexpression of a mutant protein (K80Q) mimicking constitutive acetylation of HSF1 failed to confer protection against glucolipotoxicity. Finally, we showed that expression of HSF1 and its target genes were altered in islets from diabetic GK rats, suggesting that this pathway could participate in the pathophysiology of diabetes and constitutes a potential site for therapeutic intervention. CONCLUSIONS/INTERPRETATION Our results unravel a new mechanism by which HSF1 inhibition is required for glucolipotoxicity-induced beta cell apoptosis. Restoring HSF1 activity may represent a novel strategy for the maintenance of a functional beta cell mass. Our study supports the therapeutic potential of HSF1/heat shock protein-targeting agents in diabetes treatment.
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Affiliation(s)
- Indri Purwana
- Alberta Diabetes Institute, University of Alberta, Li Ka Shing Centre, Edmonton, AB, T6G 2E1, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada
| | - Jun J Liu
- Laboratoire Biologie et Pathologie du Pancréas Endocrine (B2PE), Unité Biologie Fonctionnelle et Adaptive (BFA), Centre national de la recherche scientifique (CNRS), Unité mixte de recherche (UMR) 8251, Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France
| | - Bernard Portha
- Laboratoire Biologie et Pathologie du Pancréas Endocrine (B2PE), Unité Biologie Fonctionnelle et Adaptive (BFA), Centre national de la recherche scientifique (CNRS), Unité mixte de recherche (UMR) 8251, Université Paris Diderot, Sorbonne-Paris-Cité, Paris, France
| | - Jean Buteau
- Alberta Diabetes Institute, University of Alberta, Li Ka Shing Centre, Edmonton, AB, T6G 2E1, Canada.
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, Canada.
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17
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Li C, Yang M, Hou G, Liu S, Huan Y, Yu D, Sun S, Liu Q, Yan S, Shen Z. A Human Glucagon-Like Peptide-1-albumin Recombinant Protein with Prolonged Hypoglycemic Effect Provides Efficient and Beneficial Control of Glucose Metabolism in Diabetic Mice. Biol Pharm Bull 2017. [PMID: 28626167 DOI: 10.1248/bpb.b17-00169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
GW002 is a recombinant protein engineered by fusing the C-terminal region of human glucagon-like peptide-1 (GLP-1) to the N-terminal region of human serum albumin (HSA) with a peptide linker. This study aims to evaluate its anti-diabetic effects both in vitro and in vivo. The GLP-1 receptor-dependent luciferase reporter plasmid was transiently transfected in NIT-1 cells to calculate the half-maximal concentration (EC50) for GLP-1 receptor activation, and normal ICR mice and diabetic KKAy mice were acutely injected with GW002 (1, 3, 9 mg/kg) subcutaneously to evaluate the hypoglycemic action, while the diabetic KKAy and db/db mice were treated with GW002 once daily for 7 weeks to evaluate the effects on glucose metabolism. The results showed that GW002 activated GLP-1 receptor in NIT-1 cells with higher EC50 versus exendin-4 (46.7 vs. 7.89 nM), and single subcutaneous injection of GW002 at doses of 1, 3 and 9 mg/kg efficiently restrained the glycemia variation after oral glucose loading in ICR mice for at least 4 d, as well as reducing the non-fasting blood glucose in KKAy mice for about 2 d, while repeated injections of GW002 significantly improved abnormal glycaemia, hemoglobin (Hb)A1c levels, oral glucose intolerance and β-cell function in diabetic db/db mice. These results suggested that GW002 showed prolonged hypoglycemic action by activating its cognate receptor and provided efficient control of glucose metabolism. Thus GW002 may be a potential treatment for the management of type 2 diabetes.
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Affiliation(s)
- Caina Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Miaomiao Yang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Guojiang Hou
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Shuainan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Yi Huan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | | | - Sujuan Sun
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | - Quan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
| | | | - Zhufang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College
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Tsuchiya T, Endo A, Tsujikado K, Inukai T. Involvement of Resveratrol and ω-3 Polyunsaturated Fatty Acids on Sirtuin 1 Gene Expression in THP1 Cells. Am J Med Sci 2017; 354:415-422. [PMID: 29078847 DOI: 10.1016/j.amjms.2017.06.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 05/02/2017] [Accepted: 06/07/2017] [Indexed: 12/20/2022]
Abstract
BACKGROUND Resveratrol, a kind of polyphenol, has the potential to activate the longevity gene in several cells, in the same manner as calorie restriction. We investigated the effect of resveratrol and ω-3-line polyunsaturated fatty acid on surtuin 1 (SIRT1) gene expression in human monocytes (THP1) cells. MATERIALS AND METHODS We examined the gene expression of THP1 cells using real-time polymerase chain reaction and Western blotting analysis. Resveratol, eicosapentaenoic acid (EPA) and docosahexaeanoic acid (DHA) as n-3 polyunsaturated fatty acid were added on THP1 cells. We observed the changes in the SIRT1 gene expression in those cells, under various doses of agents and in time courses. Then, we examined the interaction of glucose and mannitol on those agents׳ effect of the gene expression. The concentration range of glucose and mannitol was from 5-20mM, respectively. RESULTS The SIRT1 gene expression could be defined in 24 and 48 hours both in real-time polymerase chain reaction analysis and in Western blotting. Resveratrol showed SIRT1 gene expression in a dose-dependent manner in the range of 0-20μM in both analyses. Although EPA at 10μM showed marked increase in SIRT1 gene expression compared to control condition in Western blotting, this phenomenon was not in dose-dependent manner. DHA did not exhibit any augmentation of SIRT1 gene expression in a dose-dependent manner in the range of 0-20μM in both analyses. We refined the dose-dependent inhibition of the SIRT1 gene expression within 20mM glucose medium. Although 20mM did not exhibit any inhibition, 10μM resveratrol induced the gene expression compared to control medium. Both 5 and 15mM mannitol medium did not significantly alter basic gene expression and 10μM resveratrol-induced gene expression. CONCLUSIONS The present results suggest that resveratrol and EPA, but not DHA, markedly activated the SIRT1 gene expression in THP1 cells, and that high glucose medium could inhibit the basic gene expression, but not powerful resveratrol-induced gene expression, in those cells.
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Affiliation(s)
- Takafumi Tsuchiya
- Department of Internal Medicine, Koshigaya Hospital, Dokkyo Medical University, Koshigaya, Japan
| | - Ayano Endo
- Department of Joint Research Center, Koshigaya Hospital, Dokkyo Medical University, Koshigaya, Japan
| | - Kyoko Tsujikado
- Department of Joint Research Center, Koshigaya Hospital, Dokkyo Medical University, Koshigaya, Japan
| | - Toshihiko Inukai
- Department of Internal Medicine, Koshigaya Hospital, Dokkyo Medical University, Koshigaya, Japan.
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Insulin secretion impairment in Sirt6 knockout pancreatic β cells is mediated by suppression of the FoxO1-Pdx1-Glut2 pathway. Sci Rep 2016; 6:30321. [PMID: 27457971 PMCID: PMC4960548 DOI: 10.1038/srep30321] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/04/2016] [Indexed: 01/29/2023] Open
Abstract
Sirtuin 6 (Sirt6), a chromatin associated class III deacetylase, controls whole-body energy homeostasis and has a critical role in glucose-stimulated insulin secretion (GSIS) in pancreatic β cells. However, its underlying molecular mechanism remains poorly understood. To gain further insights, we studied the pathway by which Sirt6 regulates GSIS utilizing mice lacking Sirt6 in their β cells (βS6KO). Further, we overexpressed wild type or deacetylase-inactive mutant Sirt6 in isolated islets as well as in MIN6 cells. We confirmed that βS6KO mice developed glucose intolerance with severely impaired GSIS. Gene expression analysis of knockout islets and overexpression studies demonstrated that Sirt6 deacetylates forkhead box protein O1 (FoxO1) to trigger its nuclear export and releases its transcriptional repression of key glucose sensing genes such as Pdx1 and Glut2. Ectopic overexpression of Sirt6 in knockout islets resulted in rescue of the defective insulin secretion and restoration of the expression of Pdx1 and Glut2. These results show that Sirt6 in pancreatic β cells deacetylates FoxO1 and subsequently increases the expression of Pdx1 and Glut2 to maintain the glucose-sensing ability of pancreatic β cells and systemic glucose tolerance.
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Yan C, Chen J, Li M, Xuan W, Su D, You H, Huang Y, Chen N, Liang X. A decrease in hepatic microRNA-9 expression impairs gluconeogenesis by targeting FOXO1 in obese mice. Diabetologia 2016; 59:1524-1532. [PMID: 27003684 DOI: 10.1007/s00125-016-3932-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/29/2016] [Indexed: 01/08/2023]
Abstract
AIM/HYPOTHESIS MicroRNA-9 (miR-9) is involved in the regulation of pancreatic beta cell function. However, its role in gluconeogenesis is still unclear. Our objective was to investigate the role of miR-9 in hepatic glucose production (HGP). METHODS MiR-9 expression was measured in livers of high-fat diet (HFD) mice and ob/ob mice. The methylation status of the miR-9-3 promoter regions in hepatocytes was determined by the methylation-specific PCR procedure. The binding activity of DNA methyltransferase (DNMT)1, DNMT3a and DNMT3b on the miR-9-3 promoter was detected by chromatin immunoprecipitation (ChIP) and quantitative real-time PCR assays. HGP was evaluated in vitro and in vivo. Glucose tolerance, insulin tolerance and pyruvate tolerance tests were also performed. RESULTS Reduced miR-9 expression and hypermethylation of the miR-9-3 promoter were observed in the livers of obese mice. Further study showed that the binding of DNMT1, but not of DNMT3a and DNMT3b, to the miR-9-3 promoter was increased in hepatocytes from ob/ob mice. Knockdown of DNMT1 alleviated the decrease in hepatic miR-9 expression in vivo and in vitro. Overexpression of hepatic miR-9 improved insulin sensitivity in obese mice and inhibited HGP. In addition, deletion of hepatic miR-9 led to an increase in random and fasting blood glucose levels in lean mice. Importantly, silenced forkhead box O1 (FOXO1) expression reversed the gluconeogenesis and glucose production in hepatocytes induced by miR-9 deletion. CONCLUSIONS/INTERPRETATION Our observations suggest that the decrease in miR-9 expression contributes to an inappropriately activated gluconeogenesis in obese mice.
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Affiliation(s)
- Caifeng Yan
- Department of Endocrinology, Clinical Medical College of Yangzhou University, Yangzhou, China
- Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
| | - Jinfeng Chen
- Department of Endocrinology, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, China
| | - Min Li
- Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
| | - Wenying Xuan
- Center of Pathology and Clinical Laboratory, Mingde Hospital of Nanjing Medical University, Nanjing, China
| | - Dongming Su
- Center of Pathology and Clinical Laboratory, Mingde Hospital of Nanjing Medical University, Nanjing, China
| | - Hui You
- Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
| | - Yujie Huang
- Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China
| | - Nuoqi Chen
- Department of Endocrinology, Zhangzhou Affiliated Hospital of Fujian Medical University, Zhangzhou, China
| | - Xiubin Liang
- Department of Pathophysiology, Jiangsu Key Laboratory of Xenotransplantation, Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
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Chen Z, Meng C, Liu J, Zhang J, Kou Y, Zhang L, Wang Z. Effects of gastric bypass on FoxO1 expression in the liver and pancreas of diabetic rats. Endocr Res 2016; 41:57-63. [PMID: 26727601 DOI: 10.3109/07435800.2015.1044010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
AIM To explore the mechanism by which gastric bypass surgery (GBS) ameliorates type 2 diabetes mellitus (T2DM) by investigating whether FoxO1 (a transcription factor that plays a crucial role in the regulation of glycolipid metabolism) expression is altered in the liver and pancreatic islet cells in a rat model of GBS-treated T2DM. METHODS Sprague-Dawley rats were randomly divided into four groups (n = 10 rats each): diabetic rats treated by GBS (DM + GBS), diabetic rats subjected to sham operation (DM + sham), normal control rats (control), and diabetic rats without surgery (DM). Fasting levels of blood glucose (BG), insulin, and glucagon-like peptide-1 (GLP-1) were measured in all groups before and 4, 8, 16, and 24 weeks after operation. Rats were killed 24 weeks after surgery. Liver and pancreas expressions of FoxO1 were investigated by immunohistochemistry and Western blotting analyses. RESULTS In the DM + GBS group, fasting BG before and 24 weeks after surgery decreased from 20.2 ± 2.1 to 7.7 ± 1.1 mmol/L, respectively; fasting insulin showed no change (2.9 ± 0.1 and 3.0 ± 0.1 mU/L, respectively); and fasting GLP-1 increased from 8.7 ± 0.9 to 23.5 ± 0.2 pmol/L, respectively. Fasting BG levels after surgery in the DM + GBS group were significantly lower than those in the DM + sham and DM groups. FoxO1 expression levels in the liver and pancreatic islets of the DM + GBS group were reduced compared to those in the DM + sham and DM groups. FoxO1 in the pancreatic β-cells was expressed mainly in the cytoplasm. CONCLUSIONS Gastric bypass may improve type 2 diabetes mellitus by changing FoxO1 expression in the liver and pancreatic islet cells.
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Affiliation(s)
| | | | - Jiyuan Liu
- a Department of Gastrointestinal Surgery and
| | - Jun Zhang
- a Department of Gastrointestinal Surgery and
| | - Yao Kou
- a Department of Gastrointestinal Surgery and
| | | | - Zhihong Wang
- b Department of Endocrinology , The First Affiliated Hospital of Chongqing Medical University , Chongqing , China
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Zhang Y, Xu F, Liang H, Cai M, Wen X, Li X, Weng J. Exenatide inhibits the growth of endometrial cancer Ishikawa xenografts in nude mice. Oncol Rep 2015; 35:1340-8. [PMID: 26648451 DOI: 10.3892/or.2015.4476] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 10/06/2015] [Indexed: 11/05/2022] Open
Abstract
Studies have showed that diabetes is one of the high risk factors of endometrial cancer; however, no reports describe the anti- or pro-cancer effect of a new kind of anti-diabetes drug, glucagon-like peptide-1 receptor agonist exenatide (exendin-4), on endometrial cancer. To investigate whether exenatide promotes or inhibits the growth of endometrial cancer, we used the subcutaneous human endometrial cancer cell Ishikawa xenografts in nude mouse model, and divided them into control group and exenatide-treated group. The tumor growth rate in exenatide group was slower than that in control group, and the apoptosis rate of exenatide group was higher than that in control group. In vitro, exendin-4 also attenuated Ishikawa cell viability and clone formation rate, but promoted cell apoptosis. There was an increase of phosphorylated-AMPK protein, a decrease of phosphorylated-mTOR protein both in vivo and in vitro after exenatide or exendin-4 treatment. Moreover, when treated with exendin-4 plus AICAR, an AMPK activator, cell apoptosis increased with higher ratio of phosphorylayed-AMPK/AMPK, lower ratio of phosphorylated-mTOR/mTOR and higher expression of cleaved caspase-3 than those in exendin-4 alone group, and the results were the opposite when treated with exendin-4 plus compound C, an AMPK inhibitor. Our results suggest that exenatide could attenuate the growth of endometrial cancer Ishikawa xenografts in nude mice, and AMPK may be the target of the mechanism.
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Affiliation(s)
- Yu Zhang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Fen Xu
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Hua Liang
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Mengyin Cai
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Xinqiao Wen
- Department of Urology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Xiaomao Li
- Department of Gynecology, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
| | - Jianping Weng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou 510630, P.R. China
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Stewart AF, Hussain MA, García-Ocaña A, Vasavada RC, Bhushan A, Bernal-Mizrachi E, Kulkarni RN. Human β-cell proliferation and intracellular signaling: part 3. Diabetes 2015; 64:1872-85. [PMID: 25999530 PMCID: PMC4439562 DOI: 10.2337/db14-1843] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This is the third in a series of Perspectives on intracellular signaling pathways coupled to proliferation in pancreatic β-cells. We contrast the large knowledge base in rodent β-cells with the more limited human database. With the increasing incidence of type 1 diabetes and the recognition that type 2 diabetes is also due in part to a deficiency of functioning β-cells, there is great urgency to identify therapeutic approaches to expand human β-cell numbers. Therapeutic approaches might include stem cell differentiation, transdifferentiation, or expansion of cadaver islets or residual endogenous β-cells. In these Perspectives, we focus on β-cell proliferation. Past Perspectives reviewed fundamental cell cycle regulation and its upstream regulation by insulin/IGF signaling via phosphatidylinositol-3 kinase/mammalian target of rapamycin signaling, glucose, glycogen synthase kinase-3 and liver kinase B1, protein kinase Cζ, calcium-calcineurin-nuclear factor of activated T cells, epidermal growth factor/platelet-derived growth factor family members, Wnt/β-catenin, leptin, and estrogen and progesterone. Here, we emphasize Janus kinase/signal transducers and activators of transcription, Ras/Raf/extracellular signal-related kinase, cadherins and integrins, G-protein-coupled receptors, and transforming growth factor β signaling. We hope these three Perspectives will serve to introduce these pathways to new researchers and will encourage additional investigators to focus on understanding how to harness key intracellular signaling pathways for therapeutic human β-cell regeneration for diabetes.
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Affiliation(s)
- Andrew F Stewart
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Mehboob A Hussain
- Departments of Medicine and Pediatrics, Johns Hopkins School of Medicine, Baltimore, MD
| | - Adolfo García-Ocaña
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Rupangi C Vasavada
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Anil Bhushan
- Diabetes Center, University of California, San Francisco, San Francisco, CA
| | - Ernesto Bernal-Mizrachi
- Division of Metabolism, Endocrinology & Diabetes, University of Michigan, Ann Arbor, MI, and VA Ann Arbor Healthcare System, Ann Arbor, MI
| | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, MA
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Tu P, Li X, Ma B, Duan H, Zhang Y, Wu R, Ni Z, Jiang P, Wang H, Li M, Zhu J, Li M. Liver histone H3 methylation and acetylation may associate with type 2 diabetes development. J Physiol Biochem 2015; 71:89-98. [DOI: 10.1007/s13105-015-0385-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/21/2015] [Indexed: 01/11/2023]
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Quiñones M, Al-Massadi O, Fernø J, Nogueiras R. Cross-talk between SIRT1 and endocrine factors: effects on energy homeostasis. Mol Cell Endocrinol 2014; 397:42-50. [PMID: 25109279 DOI: 10.1016/j.mce.2014.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 08/01/2014] [Accepted: 08/01/2014] [Indexed: 12/14/2022]
Abstract
The mammalian sirtuins (SIRT1-7) are a family of highly conserved nicotine adenine dinucleotide (NAD(+))-dependent deacetylases that act as cellular sensors to detect energy availability. SIRT1 is a multifaceted protein that is involved in a wide variety of cellular processes. SIRT1 is activated in response to caloric restriction, acting on multiple targets in a wide range of tissues. SIRT1 regulates the role of multiple hormones implicated in energy balance, including glucose and lipid metabolism. Here, we review the relevant role of SIRT1 as a mediator of endocrine function of several hormones to modulate energy balance. In addition, we analyze the potential of targeting SIRT1 for the treatment of obesity and type 2 diabetes mellitus.
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Affiliation(s)
- Mar Quiñones
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain.
| | - Omar Al-Massadi
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain
| | - Johan Fernø
- Department of Clinical Science, K. G. Jebsen Center for Diabetes Research, University of Bergen, Bergen, Norway
| | - Ruben Nogueiras
- Department of Physiology, School of Medicine-CIMUS, Instituto de Investigacion Sanitaria (IDIS), CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), University of Santiago de Compostela, San Francisco s/n, Santiago de Compostela (A Coruña), 15782, and Avda. Barcelona 3, 15782, Santiago de Compostela, Spain.
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Rouse R, Zhang L, Shea K, Zhou H, Xu L, Stewart S, Rosenzweig B, Zhang J. Extended exenatide administration enhances lipid metabolism and exacerbates pancreatic injury in mice on a high fat, high carbohydrate diet. PLoS One 2014; 9:e109477. [PMID: 25291183 PMCID: PMC4188617 DOI: 10.1371/journal.pone.0109477] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/31/2014] [Indexed: 12/22/2022] Open
Abstract
This study expanded upon a previous study in mice reporting a link between exenatide treatment and exocrine pancreatic injury by demonstrating temporal and dose responses and providing an initial mechanistic hypothesis. The design of the present study included varying lengths of exenatide exposure (3, 6 weeks to 12 weeks) at multiple concentrations (3, 10, or 30 µg/kg) with multiple endpoints (histopathology evaluations, immunoassay for cytokines, immunostaining of the pancreas, serum chemistries and measurement of trypsin, amylase, and, lipase, and gene expression profiles). Time- and dose-dependent exocrine pancreatic injury was observed in mice on a high fat diet treated with exenatide. The morphological changes identified in the pancreas involved acinar cell injury and death (autophagy, apoptosis, necrosis, and atrophy), cell adaptations (hypertrophy and hyperplasia), and cell survival (proliferation/regeneration) accompanied by varying degrees of inflammatory response leading to secondary injury in pancreatic blood vessels, ducts, and adipose tissues. Gene expression profiles indicated increased signaling for cell survival and altered lipid metabolism in exenatide treated mice. Immunohistochemistry supported gene expression findings that exenatide caused and/or exacerbated pancreatic injury in a high fat diet environment potentially by further increasing high fat diet exacerbated lipid metabolism and resulting oxidative stress. Further investigation is required to confirm these findings and determine their relevance to human disease.
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Affiliation(s)
- Rodney Rouse
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Leshuai Zhang
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Katherine Shea
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Hongfei Zhou
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Lin Xu
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Sharron Stewart
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Barry Rosenzweig
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
| | - Jun Zhang
- Division of Applied Regulatory Science, Center for Drug Evaluation and Research, U. S. Food and Drug Administration, Silver Spring, Maryland, United States of America
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/01/2022]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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Nadkarni P, Chepurny OG, Holz GG. Regulation of glucose homeostasis by GLP-1. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2014; 121:23-65. [PMID: 24373234 DOI: 10.1016/b978-0-12-800101-1.00002-8] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Glucagon-like peptide-1(7-36)amide (GLP-1) is a secreted peptide that acts as a key determinant of blood glucose homeostasis by virtue of its abilities to slow gastric emptying, to enhance pancreatic insulin secretion, and to suppress pancreatic glucagon secretion. GLP-1 is secreted from L cells of the gastrointestinal mucosa in response to a meal, and the blood glucose-lowering action of GLP-1 is terminated due to its enzymatic degradation by dipeptidyl-peptidase-IV (DPP-IV). Released GLP-1 activates enteric and autonomic reflexes while also circulating as an incretin hormone to control endocrine pancreas function. The GLP-1 receptor (GLP-1R) is a G protein-coupled receptor that is activated directly or indirectly by blood glucose-lowering agents currently in use for the treatment of type 2 diabetes mellitus (T2DM). These therapeutic agents include GLP-1R agonists (exenatide, liraglutide, lixisenatide, albiglutide, dulaglutide, and langlenatide) and DPP-IV inhibitors (sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin). Investigational agents for use in the treatment of T2DM include GPR119 and GPR40 receptor agonists that stimulate the release of GLP-1 from L cells. Summarized here is the role of GLP-1 to control blood glucose homeostasis, with special emphasis on the advantages and limitations of GLP-1-based therapeutics.
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Affiliation(s)
- Prashant Nadkarni
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Joslin Diabetes Center, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - Oleg G Chepurny
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA
| | - George G Holz
- Department of Medicine, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA; Department of Pharmacology, State University of New York (SUNY), Upstate Medical University, Syracuse, New York, USA.
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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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Abstract
Pancreatic beta-cell mass expands through beta-cell proliferation and neogenesis while it decreases mainly via apoptosis. The loss of balance between beta-cell death and regeneration leads to a reduction of beta-cell functional mass, thus contributing to the pathogenesis of type 2 diabetes mellitus (T2DM). The pathogenetic mechanisms causing T2DM are complex, and also include a significant reduction of the incretin effect. A better understanding of the role of incretin hormones in glucose homeostasis has led to the development of incretin-based therapies. Recently, incretin hormones have been shown to stimulate the beta-cell growth and differentiation from pancreas-derived stem/progenitor cells, as well as to exert cytoprotective, antiapoptotic effects on beta-cells. However, the role and the molecular mechanisms by which GLP-1 and its agonists regulate beta-cell mass have not been fully investigated. This review focuses the current findings and the missing understanding of the effects of incretin hormones on beta-cell mass expansion.
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Affiliation(s)
- Federica Tortosa
- Department of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology, Andrology and Metabolic Diseases, University of Bari School of Medicine , Bari , Italy and
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Luu L, Dai FF, Prentice KJ, Huang X, Hardy AB, Hansen JB, Liu Y, Joseph JW, Wheeler MB. The loss of Sirt1 in mouse pancreatic beta cells impairs insulin secretion by disrupting glucose sensing. Diabetologia 2013; 56:2010-20. [PMID: 23783352 DOI: 10.1007/s00125-013-2946-5] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/29/2013] [Indexed: 10/26/2022]
Abstract
AIMS/HYPOTHESIS Sirtuin 1 (SIRT1) has emerged as a key metabolic regulator of glucose homeostasis and insulin secretion. Enhanced SIRT1 activity has been shown to be protective against diabetes, although the mechanisms remain largely unknown. The aim of this study was to determine how SIRT1 regulates insulin secretion in the pancreatic beta cell. METHODS Pancreatic beta cell-specific Sirt1 deletion was induced by tamoxifen injection in 9-week-old Pdx1CreER:floxSirt1 mice (Sirt1BKO). Controls were injected with vehicle. Mice were assessed metabolically via glucose challenge, insulin tolerance tests and physical variables. In parallel, Sirt1 short interfering RNA-treated MIN6 cells (SIRT1KD) and isolated Sirt1BKO islets were used to investigate the effect of SIRT1 inactivation on insulin secretion and gene expression. RESULTS OGTTs showed impaired glucose disposal in Sirt1BKO mice due to insufficient insulin secretion. Isolated Sirt1BKO islets and SIRT1KD MIN6 cells also exhibited impaired glucose-stimulated insulin secretion. Subsequent analyses revealed impaired α-ketoisocaproic acid-induced insulin secretion and attenuated glucose-induced Ca(2+) influx, but normal insulin granule exocytosis in Sirt1BKO beta cells. Microarray studies revealed a large cluster of mitochondria-related genes, the expression of which was dysregulated in SIRT1KD MIN6 cells. Upon further analysis, we demonstrated an explicit defect in mitochondrial function: the inability to couple nutrient metabolism to mitochondrial membrane hyperpolarisation and reduced oxygen consumption rates. CONCLUSIONS/INTERPRETATION Taken together, these findings indicate that in beta cells the deacetylase SIRT1 regulates the expression of specific mitochondria-related genes that control metabolic coupling, and that a decrease in beta cell Sirt1 expression impairs glucose sensing and insulin secretion.
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Affiliation(s)
- L Luu
- Department of Physiology, University of Toronto, 1 King's College Circle Room 3352, Toronto, ON M5S 1A8, Canada
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32
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Antiproliferative effects of PACAP and VIP in serum-starved glioma cells. J Mol Neurosci 2013; 51:503-13. [PMID: 23900722 DOI: 10.1007/s12031-013-0076-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 07/15/2013] [Indexed: 01/20/2023]
Abstract
Emerging evidence have suggested that calorie restriction (CR) is a reliable method to decrease cancer development since it produces changes in tumor microenvironment that interfere with cell proliferation, tissue invasion, and formation of metastases. Studies on the role of pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) in cancer cells indicate that their influence on cell growth is either cell type specific or dependent on culture conditions. Evidence showing the effect of PACAP and VIP in glioma cells grown under conditions mimicking CR are currently unavailable. Therefore, we explored the effects of both PACAP and VIP in C6 glioma cells either grown in a normal growth medium or exposed to serum starvation, to resemble an acute condition of CR. Cell viability, expression of proteins related to cell proliferation (cyclin D1), apoptosis (Bcl2, p53, and cleaved caspase-3), and cell malignancy (GFAP and nestin) were assessed by MTT assay, immunoblot, and immunolocalization, respectively. Results demonstrated that CR significantly decreased cell proliferation, reduced levels of cyclin D1 and Bcl2, and increased the expression of p53 and cleaved caspase-3. Surprisingly, all of these CR-driven effects were further exacerbated by PACAP or VIP treatment. We also found that PACAP or VIP prevented GFAP decrease caused by CR and further reduced the expression of nestin, a prognostic marker of malignancy. In conclusion, these data demonstrate that PACAP and VIP possess antiproliferative properties against glioma cells that depend on the specific culture settings, further supporting the idea that CR might offer new avenues to improve peptide-oriented glioma cancer treatment.
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Incretin-stimulated interaction between β-cell Kv1.5 and Kvβ2 channel proteins involves acetylation/deacetylation by CBP/SirT1. Biochem J 2013; 451:227-34. [DOI: 10.1042/bj20121669] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The incretins, GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide-1) are gastrointestinal hormones conferring a number of beneficial effects on β-cell secretion, survival and proliferation. In a previous study, it was demonstrated that delayed rectifier channel protein Kv2.1 contributes to β-cell apoptosis and that the prosurvival effects of incretins involve Kv2.1 PTMs (post-translational modifications), including phosphorylation and acetylation. Since Kv1.5 overexpression was also shown to stimulate β-cell death, the present study was initiated in order to determine whether incretins modulate Kv1.5α–Kvβ2 interaction via PTM and the mechanisms involved. GIP and GLP-1 reduced apoptosis in INS-1 β-cells (clone 832/13) overexpressing Kv1.5, and RNAi (RNA interference)-mediated knockdown of endogenous Kv1.5 attenuated apoptotic β-cell death. Both GIP and GLP-1 increased phosphorylation and acetylation of Kv1.5 and its Kvβ2 protein subunit, leading to their enhanced interaction. Further studies demonstrated that CBP [CREB (cAMP-response-element-binding protein)-binding protein]/SirT1 mediated acetylation/deacetylation and interaction between Kvβ2 and Kv1.5 in response to GIP or GLP-1. Incretin regulation of β-cell function therefore involves the acetylation of multiple Kvα and Kvβ subunits.
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Morris BJ. Seven sirtuins for seven deadly diseases of aging. Free Radic Biol Med 2013; 56:133-71. [PMID: 23104101 DOI: 10.1016/j.freeradbiomed.2012.10.525] [Citation(s) in RCA: 276] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/31/2012] [Accepted: 10/05/2012] [Indexed: 12/14/2022]
Abstract
Sirtuins are a class of NAD(+)-dependent deacetylases having beneficial health effects. This extensive review describes the numerous intracellular actions of the seven mammalian sirtuins, their protein targets, intracellular localization, the pathways they modulate, and their role in common diseases of aging. Selective pharmacological targeting of sirtuins is of current interest in helping to alleviate global disease burden. Since all sirtuins are activated by NAD(+), strategies that boost NAD(+) in cells are of interest. While most is known about SIRT1, the functions of the six other sirtuins are now emerging. Best known is the involvement of sirtuins in helping cells adapt energy output to match energy requirements. SIRT1 and some of the other sirtuins enhance fat metabolism and modulate mitochondrial respiration to optimize energy harvesting. The AMP kinase/SIRT1-PGC-1α-PPAR axis and mitochondrial sirtuins appear pivotal to maintaining mitochondrial function. Downregulation with aging explains much of the pathophysiology that accumulates with aging. Posttranslational modifications of sirtuins and their substrates affect specificity. Although SIRT1 activation seems not to affect life span, activation of some of the other sirtuins might. Since sirtuins are crucial to pathways that counter the decline in health that accompanies aging, pharmacological agents that boost sirtuin activity have clinical potential in treatment of diabetes, cardiovascular disease, dementia, osteoporosis, arthritis, and other conditions. In cancer, however, SIRT1 inhibitors could have therapeutic value. Nutraceuticals such as resveratrol have a multiplicity of actions besides sirtuin activation. Their net health benefit and relative safety may have originated from the ability of animals to survive environmental changes by utilizing these stress resistance chemicals in the diet during evolution. Each sirtuin forms a key hub to the intracellular pathways affected.
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Affiliation(s)
- Brian J Morris
- Basic & Clinical Genomics Laboratory, School of Medical Sciences and Bosch Institute, Building F13, University of Sydney, NSW 2006, Australia.
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35
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Wauters E, Sanchez-Arévalo Lobo VJ, Pinho AV, Mawson A, Herranz D, Wu J, Cowley MJ, Colvin EK, Njicop EN, Sutherland RL, Liu T, Serrano M, Bouwens L, Real FX, Biankin AV, Rooman I. Sirtuin-1 regulates acinar-to-ductal metaplasia and supports cancer cell viability in pancreatic cancer. Cancer Res 2013; 73:2357-67. [PMID: 23370328 DOI: 10.1158/0008-5472.can-12-3359] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The exocrine pancreas can undergo acinar-to-ductal metaplasia (ADM), as in the case of pancreatitis where precursor lesions of pancreatic ductal adenocarcinoma (PDAC) can arise. The NAD(+)-dependent protein deacetylase Sirtuin-1 (Sirt1) has been implicated in carcinogenesis with dual roles depending on its subcellular localization. In this study, we examined the expression and the role of Sirt1 in different stages of pancreatic carcinogenesis, i.e. ADM models and established PDAC. In addition, we analyzed the expression of KIAA1967, a key mediator of Sirt1 function, along with potential Sirt1 downstream targets. Sirt1 was co-expressed with KIAA1967 in the nuclei of normal pancreatic acinar cells. In ADM, Sirt1 underwent a transient nuclear-to-cytoplasmic shuttling. Experiments where during ADM, we enforced repression of Sirt1 shuttling, inhibition of Sirt1 activity or modulation of its expression, all underscore that the temporary decrease of nuclear and increase of cytoplasmic Sirt1 stimulate ADM. Our results further underscore that important transcriptional regulators of acinar differentiation, that is, Pancreatic transcription factor-1a and β-catenin can be deacetylated by Sirt1. Inhibition of Sirt1 is effective in suppression of ADM and in reducing cell viability in established PDAC tumors. KIAA1967 expression is differentially downregulated in PDAC and impacts on the sensitivity of PDAC cells to the Sirt1/2 inhibitor Tenovin-6. In PDAC, acetylation of β-catenin is not affected, unlike p53, a well-characterized Sirt1-regulated protein in tumor cells. Our results reveal that Sirt1 is an important regulator and potential therapeutic target in pancreatic carcinogenesis.
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Affiliation(s)
- Elke Wauters
- Cancer Research Program, Garvan Institute of Medical Research, Sydney, Australia
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Tie L, An Y, Han J, Xiao Y, Xiaokaiti Y, Fan S, Liu S, Chen AF, Li X. Genistein accelerates refractory wound healing by suppressing superoxide and FoxO1/iNOS pathway in type 1 diabetes. J Nutr Biochem 2013; 24:88-96. [DOI: 10.1016/j.jnutbio.2012.02.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 01/02/2012] [Accepted: 02/17/2012] [Indexed: 01/01/2023]
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Scholar Award Recipient Dr. Jean Buteau Investigates the Role of Glucagon-Like Peptide-1 in β-Cell Neogenesis. Can J Diabetes 2012. [DOI: 10.1016/j.jcjd.2012.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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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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Berclaz C, Goulley J, Villiger M, Pache C, Bouwens A, Martin-Williams E, Van de Ville D, Davison AC, Grapin-Botton A, Lasser T. Diabetes imaging-quantitative assessment of islets of Langerhans distribution in murine pancreas using extended-focus optical coherence microscopy. BIOMEDICAL OPTICS EXPRESS 2012; 3:1365-80. [PMID: 22741082 PMCID: PMC3370976 DOI: 10.1364/boe.3.001365] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 05/07/2012] [Accepted: 05/10/2012] [Indexed: 05/19/2023]
Abstract
Diabetes is characterized by hyperglycemia that can result from the loss of pancreatic insulin secreting β-cells in the islets of Langerhans. We analyzed ex vivo the entire gastric and duodenal lobes of a murine pancreas using extended-focus Optical Coherence Microscopy (xfOCM). To identify and quantify the islets of Langerhans observed in xfOCM tomograms we implemented an active contour algorithm based on the level set method. We show that xfOCM reveals a three-dimensional islet distribution consistent with Optical Projection Tomography, albeit with a higher resolution that also enables the detection of the smallest islets (≤ 8000 μm(3)). Although this category of the smallest islets represents only a negligible volume compared to the total β-cell volume, a recent study suggests that these islets, located at the periphery, are the first to be destroyed when type I diabetes develops. Our results underline the capability of xfOCM to contribute to the understanding of the development of diabetes, especially when considering islet volume distribution instead of the total β-cell volume only.
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Affiliation(s)
- Corinne Berclaz
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
- Swiss Institute for Experimental Cancer Research (ISREC), École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Joan Goulley
- Swiss Institute for Experimental Cancer Research (ISREC), École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Martin Villiger
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Christophe Pache
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Arno Bouwens
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Erica Martin-Williams
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Dimitri Van de Ville
- Institute of Bioengineering, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
- Department of Radiology and Medical Informatics, University of Geneva, 1211 Geneva,
Switzerland
| | - Anthony C. Davison
- Chair of Statistics, MATHAA, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Anne Grapin-Botton
- Swiss Institute for Experimental Cancer Research (ISREC), École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
| | - Theo Lasser
- Laboratoire d’Optique Biomédicale, École Polytechnique Fédérale de Lausanne, 1015 Lausanne,
Switzerland
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40
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Sheline CT. Involvement of SIRT1 in Zn 2+, Streptozotocin, Non-Obese Diabetic, and Cytokine-Mediated Toxicities of β-cells. JOURNAL OF DIABETES & METABOLISM 2012; 3:1000193. [PMID: 23565341 PMCID: PMC3615451 DOI: 10.4172/2155-6156.1000193] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Zn2+ toxicity is implicated in pancreatic β-cell death that occurs secondarily to: streptozotocin exposure in vitro; and both autoimmune attack or streptozotocin in vivo models of T1DM. This is demonstrated by reduced β-cell death or diabetic incidence in vitro or in NOD mice after treatment with Zn2+ preferring chelators, pyruvate, nicotinamide, a reduced zinc diet, sirtuin inhibitors, or zinc transporter knockout. These therapeutics are also demonstrated to be efficacious against Zn2+ neurotoxicity. AIMS To determine if the sirtuin pathway is involved in Zn2+-, streptozotocin-, or cytokine-mediated β-cell death in vitro, and streptozotocin-, or NOD induced T1DM in vivo. METHODS Sensitivity of MIN6 cells expressing empty vector, sirtuin protein-1 (SIRT1) or its siRNA, to Zn2+, streptozotocin, or cytokines, and effects on NAD+ levels were determined. Covariance of manipulating SIRT1 levels with diabetic incidence was tested in vivo. RESULTS 1) sirtuin pathway inhibition or SIRT1 knockdown attenuated Zn2+-, STZ-, and cytokine-mediated toxicity and NAD+ loss in β-cells, 2) SIRT1 overexpression potentiated these toxicities, 3) young SIRT1 β-cell transgenic mice have improved glucose tolerance under basal conditions, but upon aging showed increased sensitivity to streptozotocin compared to SIRT1 +/- mice, and 4) SIRT1 +/- mice in an NOD background or exposed to streptozotocin trended toward reduced diabetic incidence and mortality compared to wildtype. CONCLUSIONS These results have implicated SIRT1-mediated NAD+ loss in Zn2+, STZ, or cytokine toxicities of MIN6, and in NOD or streptozotocin T1DM animal models. Modulation of β-cell Zn2+ and NAD+ levels, and the sirtuin pathway could be novel therapeutic targets for T1DM.
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Abstract
This review considers the role of α-cells in β-cell generation and regeneration. We present recent evidence obtained from lineage-tracing studies showing that α-cells can serve as progenitors of β-cells and present a hypothetical model how injured β-cells might activate α-cells in adult islets to promote β-cell regeneration. β-cells appear to arise by way of their trans-differentiation from undifferentiated α progenitor cells, pro-α-cells, both during embryonic development of the islets and in the adult pancreas in response to β-cell injuries. Plasticity of α-cells is endowed by the expression of the gene encoding proglucagon, a prohormone that can give rise to glucagon and glucagon-like peptides (GLPs). The production of glucagon from proglucagon is characteristic of fully-differentiated α-cells whereas GLP-1 is a product of undifferentiated α-cells. GLP-1, a cell growth and survival factor, is proposed to promote the expansion of neurogenin3-expressing, undifferentiated pro-α-cells during development. β-cells arise from pro-α-cells by a change in the relative amounts of the transcription factors Arx and Pax4, master regulators of the α- and β-cell lineages, respectively. A paracrine/autocrine model is proposed whereby injuries of β-cells in adult islets induce the production and release of factors, such as stromal cell-derived factor-1, that cause the de-differentiation of adjacent α-cells into pro-α-cells. Pro-α-cells produce GLP-1 and its receptor that renders them competent to trans-differentiate into β-cells. The trans-differentiation of pro-α-cells into β-cells provides a potentially exploitable mechanism for the regeneration of β-cells in individuals with type 1 diabetes.
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Affiliation(s)
- Joel F Habener
- Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Boston, MA, USA.
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Chloroquine-mediated lysosomal dysfunction enhances the anticancer effect of nutrient deprivation. Pharm Res 2012; 29:2249-63. [PMID: 22538436 DOI: 10.1007/s11095-012-0753-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 04/02/2012] [Indexed: 12/12/2022]
Abstract
PURPOSE To investigate the ability of chloroquine, a lysosomotropic autophagy inhibitor, to enhance the anticancer effect of nutrient deprivation. METHODS Serum-deprived U251 glioma, B16 melanoma and L929 fibrosarcoma cells were treated with chloroquine in vitro. Cell viability was measured by crystal violet and MTT assay. Oxidative stress, apoptosis/necrosis and intracellular acidification were analyzed by flow cytometry. Cell morphology was examined by light and electron microscopy. Activation of AMP-activated protein kinase (AMPK) and autophagy were monitored by immunoblotting. RNA interference was used for AMPK and LC3b knockdown. The anticancer efficiency of intraperitoneal chloroquine in calorie-restricted mice was assessed using a B16 mouse melanoma model. RESULTS Chloroquine rapidly killed serum-starved cancer cells in vitro. This effect was not mimicked by autophagy inhibitors or LC3b shRNA, indicating autophagy-independent mechanism. Chloroquine-induced lysosomal accumulation and oxidative stress, leading to mitochondrial depolarization, caspase activation and mixed apoptotic/necrotic cell death, were prevented by lysosomal acidification inhibitor bafilomycin. AMPK downregulation participated in chloroquine action, as AMPK activation reduced, and AMPK shRNA mimicked chloroquine toxicity. Chloroquine inhibited melanoma growth in calorie-restricted mice, causing lysosomal accumulation, mitochondrial disintegration and selective necrosis of tumor cells. CONCLUSION Combined treatment with chloroquine and calorie restriction might be useful in cancer therapy.
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