51
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Guo R, Liu W, Liu B, Zhang B, Li W, Xu Y. SIRT1 suppresses cardiomyocyte apoptosis in diabetic cardiomyopathy: An insight into endoplasmic reticulum stress response mechanism. Int J Cardiol 2015; 191:36-45. [PMID: 25965594 DOI: 10.1016/j.ijcard.2015.04.245] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 04/05/2015] [Accepted: 04/30/2015] [Indexed: 02/08/2023]
Abstract
BACKGROUND Endoplasmic reticulum (ER) stress-dependent apoptosis had been shown to occur in the hearts of people with diabetes, although the exact mechanisms are unclear. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide NAD(+)-dependent deacetylase, is known to play a role in diabetes-related complications as well as ER-stress. Therefore, we investigated the relationship between Sirtuin 1 (SIRT1) and ER stress-induced apoptosis in H9C2 cardiomyocyte. METHODS Diabetic rats were established by a single intraperitoneal injection of streptozotocin (STZ; 50mg/kg) with high-fat diet. For in vitro analysis, rat derived H9C2 cardiomyocytes were cultured. Cardiac function was assessed by Doppler, and SIRT1 as well as ER stress related protein expressions were measured by immunohistochemistry and western blotting. Cultured cells were exposed to advanced glycation end products (AGEs) (400μg/mL) for inducing ER stress and apoptosis. Cell apoptosis were detected by flow cytometry. RESULTS In vivo, ER stress was enhanced in the cardiomyocytes of diabetic rats without any treatments. A SIRT1 activator, resveratrol, could significantly restore cardiac function, reduce cardiomyocyte apoptosis, and ameliorate ER stress. In vitro, we showed that apoptosis and ER stress increased after AGE stimulation when SIRT1 expression was downregulated by short interfering RNA (siRNA) (p<0.05). However, resveratrol (10μM) restored SIRT1 levels in cardiomyocytes and markedly reduced ER stress-mediated apoptosis. CONCLUSION SIRT1 may attenuate ER stress-induced cardiomyocyte apoptosis via PERK/eIF2α, ATF6/CHOP, and IRE1α/JNK-mediated pathways. This study may provide insights into a novel underlying mechanism and a strategy for treating diabetic cardiomyopathy.
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Affiliation(s)
- Rong Guo
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, PR China; Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA.
| | - Weijing Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, PR China
| | - Baoxin Liu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, PR China
| | - Buchun Zhang
- Department of Cardiology, the Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, PR China
| | - Weiming Li
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, PR China
| | - Yawei Xu
- Department of Cardiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai 200072, PR China.
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52
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González-Rodríguez Á, Santamaría B, Mas-Gutierrez JA, Rada P, Fernández-Millán E, Pardo V, Álvarez C, Cuadrado A, Ros M, Serrano M, Valverde ÁM. Resveratrol treatment restores peripheral insulin sensitivity in diabetic mice in a sirt1-independent manner. Mol Nutr Food Res 2015; 59:1431-42. [DOI: 10.1002/mnfr.201400933] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/18/2015] [Accepted: 03/20/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Águeda González-Rodríguez
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
| | - Beatriz Santamaría
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
| | | | - Patricia Rada
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), ISCIII; Spain
| | - Elisa Fernández-Millán
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
- Departamento de Bioquímica y Biología Molecular II; Facultad de Farmacia; Universidad Complutense de Madrid; Madrid Spain
| | - Virginia Pardo
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
| | - Carmen Álvarez
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
- Departamento de Bioquímica y Biología Molecular II; Facultad de Farmacia; Universidad Complutense de Madrid; Madrid Spain
| | - Antonio Cuadrado
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), ISCIII; Spain
- Instituto de Investigacion Sanitaria La Paz (IdiPaz); Madrid Spain
| | - Manuel Ros
- Facultad de Ciencias; Universidad Rey Juan Carlos; Madrid Spain
| | - Manuel Serrano
- Spanish National Cancer Research Centre (CNIO); Madrid Spain
| | - Ángela M. Valverde
- Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC/UAM); Madrid Spain
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII; Spain
- Instituto de Investigacion Sanitaria La Paz (IdiPaz); Madrid Spain
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53
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Wang Y, Chen Y, Wang H, Cheng Y, Zhao X. Specific Turn-On Fluorescent Probe with Aggregation-Induced Emission Characteristics for SIRT1 Modulator Screening and Living-Cell Imaging. Anal Chem 2015; 87:5046-9. [DOI: 10.1021/acs.analchem.5b01069] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Yi Wang
- College
of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang China
| | - Yaqi Chen
- College
of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang China
| | - Haibo Wang
- College
of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang China
| | - Yiyu Cheng
- College
of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang China
| | - Xiaoping Zhao
- College
of Preclinical Medicine, Zhejiang Chinese Medical University, Hangzhou, Zhejiang China
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54
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Maiese K. Novel applications of trophic factors, Wnt and WISP for neuronal repair and regeneration in metabolic disease. Neural Regen Res 2015; 10:518-28. [PMID: 26170801 PMCID: PMC4424733 DOI: 10.4103/1673-5374.155427] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/02/2015] [Indexed: 12/13/2022] Open
Abstract
Diabetes mellitus affects almost 350 million individuals throughout the globe resulting in significant morbidity and mortality. Of further concern is the growing population of individuals that remain undiagnosed but are susceptible to the detrimental outcomes of this disorder. Diabetes mellitus leads to multiple complications in the central and peripheral nervous systems that include cognitive impairment, retinal disease, neuropsychiatric disease, cerebral ischemia, and peripheral nerve degeneration. Although multiple strategies are being considered, novel targeting of trophic factors, Wnt signaling, Wnt1 inducible signaling pathway protein 1, and stem cell tissue regeneration are considered to be exciting prospects to overcome the cellular mechanisms that lead to neuronal injury in diabetes mellitus involving oxidative stress, apoptosis, and autophagy. Pathways that involve insulin-like growth factor-1, fibroblast growth factor, epidermal growth factor, and erythropoietin can govern glucose homeostasis and are intimately tied to Wnt signaling that involves Wnt1 and Wnt1 inducible signaling pathway protein 1 (CCN4) to foster control over stem cell proliferation, wound repair, cognitive decline, β-cell proliferation, vascular regeneration, and programmed cell death. Ultimately, cellular metabolism through Wnt signaling is driven by primary metabolic pathways of the mechanistic target of rapamycin and AMP activated protein kinase. These pathways offer precise biological control of cellular metabolism, but are exquisitely sensitive to the different components of Wnt signaling. As a result, unexpected clinical outcomes can ensue and therefore demand careful translation of the mechanisms that govern neural repair and regeneration in diabetes mellitus.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey 07101, USA
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55
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Maiese K. FoxO Transcription Factors and Regenerative Pathways in Diabetes Mellitus. Curr Neurovasc Res 2015; 12:404-13. [PMID: 26256004 PMCID: PMC4567483 DOI: 10.2174/1567202612666150807112524] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 07/24/2015] [Accepted: 07/27/2015] [Indexed: 02/07/2023]
Abstract
Mammalian forkhead transcription factors of the O class (FoxO) are exciting targets under consideration for the development of new clinical entities to treat metabolic disorders and diabetes mellitus (DM). DM, a disorder that currently affects greater than 350 million individuals globally, can become a devastating disease that leads to cellular injury through oxidative stress pathways and affects multiple systems of the body. FoxO proteins can regulate insulin signaling, gluconeogenesis, insulin resistance, immune cell migration, and cell senescence. FoxO proteins also control cell fate through oxidative stress and pathways of autophagy and apoptosis that either lead to tissue regeneration or cell demise. Furthermore, FoxO signaling can be dependent upon signal transduction pathways that include silent mating type information regulation 2 homolog 1 (S. cerevisiae) (SIRT1), Wnt, and Wnt1 inducible signaling pathway protein 1 (WISP1). Cellular metabolic pathways driven by FoxO proteins are complex, can lead to variable clinical outcomes, and require in-depth analysis of the epigenetic and post-translation protein modifications that drive FoxO protein activation and degradation.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey 07101, USA.
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56
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Maiese K. Programming apoptosis and autophagy with novel approaches for diabetes mellitus. Curr Neurovasc Res 2015; 12:173-88. [PMID: 25742566 PMCID: PMC4380829 DOI: 10.2174/1567202612666150305110929] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 02/16/2015] [Accepted: 02/19/2015] [Indexed: 12/13/2022]
Abstract
According to the World Health Organization, diabetes mellitus (DM) in the year 2030 will be ranked the seventh leading cause of death in the world. DM impacts all systems of the body with oxidant stress controlling cell fate through endoplasmic reticulum stress, mitochondrial dysfunction, alterations in uncoupling proteins, and the induction of apoptosis and autophagy. Multiple treatment approaches are being entertained for DM with Wnt1 inducible signaling pathway protein 1 (WISP1), mechanistic target of rapamycin (mTOR), and silent mating type information regulation 2 homolog) 1 (S. cerevisiae) (SIRT1) generating significant interest as target pathways that can address maintenance of glucose homeostasis as well as prevention of cellular pathology by controlling insulin resistance, stem cell proliferation, and the programmed cell death pathways of apoptosis and autophagy. WISP1, mTOR, and SIRT1 can rely upon similar pathways such as AMP activated protein kinase as well as govern cellular metabolism through cytokines such as EPO and oral hypoglycemics such as metformin. Yet, these pathways require precise biological control to exclude potentially detrimental clinical outcomes. Further elucidation of the ability to translate the roles of WISP1, mTOR, and SIRT1 into effective clinical avenues offers compelling prospects for new therapies against DM that can benefit hundreds of millions of individuals throughout the globe.
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Affiliation(s)
- Kenneth Maiese
- MD, Cellular and Molecular Signaling, Newark, New Jersey 07101, USA.
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57
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Escande C, Nin V, Pirtskhalava T, Chini CCS, Tchkonia T, Kirkland JL, Chini EN. Deleted in breast cancer 1 limits adipose tissue fat accumulation and plays a key role in the development of metabolic syndrome phenotype. Diabetes 2015; 64:12-22. [PMID: 25053585 PMCID: PMC4274806 DOI: 10.2337/db14-0192] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Obesity is often regarded as the primary cause of metabolic syndrome. However, many lines of evidence suggest that obesity may develop as a protective mechanism against tissue damage during caloric surplus and that it is only when the maximum fat accumulation capacity is reached and fatty acid spillover occurs into to peripheral tissues that metabolic diseases develop. In this regard, identifying the molecular mechanisms that modulate adipocyte fat accumulation and fatty acid spillover is imperative. Here we identify the deleted in breast cancer 1 (DBC1) protein as a key regulator of fat storage capacity of adipocytes. We found that knockout (KO) of DBC1 facilitated fat cell differentiation and lipid accumulation and increased fat storage capacity of adipocytes in vitro and in vivo. This effect resulted in a "healthy obesity" phenotype. DBC1 KO mice fed a high-fat diet, although obese, remained insulin sensitive, had lower free fatty acid in plasma, were protected against atherosclerosis and liver steatosis, and lived longer. We propose that DBC1 is part of the molecular machinery that regulates fat storage capacity in adipocytes and participates in the "turn-off" switch that limits adipocyte fat accumulation and leads to fat spillover into peripheral tissues, leading to the deleterious effects of caloric surplus.
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Affiliation(s)
- Carlos Escande
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN Institut Pasteur Montevideo, Montevideo, Uruguay
| | - Veronica Nin
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | | | - Claudia C S Chini
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
| | | | | | - Eduardo N Chini
- Kogod Aging Center, Mayo Clinic, Rochester, MN Department of Anesthesiology, Mayo Clinic, Rochester, MN
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58
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Clark-Knowles KV, Dewar-Darch D, Jardine KE, McBurney MW. Modulation of tumorigenesis by dietary intervention is not mediated by SIRT1 catalytic activity. PLoS One 2014; 9:e112406. [PMID: 25380034 PMCID: PMC4224430 DOI: 10.1371/journal.pone.0112406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 10/14/2014] [Indexed: 12/31/2022] Open
Abstract
The protein deacetylase SIRT1 is involved in the regulation of a large number of cellular processes that are thought to be required for cancer initiation and progression. Both SIRT1 activity and tumorigenesis can be influenced by dietary fat and polyphenolics. We set out to determine whether dietary modulations of tumorigenesis are mediated by SIRT1 catalytic functions. We introduced a mammary gland tumor-inducing transgene, MMTV-PyMT, into stocks of mice bearing a H355Y point mutation in the Sirt1 gene that abolishes SIRT1 catalytic activity. Tumor latency was reduced in animals fed a high fat diet but this effect was not dependent on SIRT1 activity. Resveratrol had little effect on tumor formation except in animals heterozygous for the mutant Sirt1 gene. We conclude that the effects of these dietary interventions on tumorigenesis are not mediated by modulation of SIRT1 catalytic activity.
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MESH Headings
- Analysis of Variance
- Animals
- Antigens, Polyomavirus Transforming/genetics
- Antineoplastic Agents, Phytogenic/pharmacology
- Biocatalysis
- Cell Transformation, Neoplastic/drug effects
- Cell Transformation, Neoplastic/genetics
- Diet, High-Fat
- Heterozygote
- Male
- Mammary Neoplasms, Experimental/diet therapy
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/metabolism
- Mammary Tumor Virus, Mouse/genetics
- Mice, Transgenic
- Point Mutation
- Resveratrol
- Sirtuin 1/genetics
- Sirtuin 1/metabolism
- Stilbenes/pharmacology
- Tumor Burden/drug effects
- Tumor Burden/genetics
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Affiliation(s)
| | - Danielle Dewar-Darch
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Karen E. Jardine
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Michael W. McBurney
- Centre for Cancer Therapeutics, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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59
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White AT, Philp A, Fridolfsson HN, Schilling JM, Murphy AN, Hamilton DL, McCurdy CE, Patel HH, Schenk S. High-fat diet-induced impairment of skeletal muscle insulin sensitivity is not prevented by SIRT1 overexpression. Am J Physiol Endocrinol Metab 2014; 307:E764-72. [PMID: 25159328 PMCID: PMC4216952 DOI: 10.1152/ajpendo.00001.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Skeletal muscle sirtuin 1 (SIRT1) expression is reduced under insulin-resistant conditions, such as those resulting from high-fat diet (HFD) feeding and obesity. Herein, we investigated whether constitutive activation of SIRT1 in skeletal muscle prevents HFD-induced muscle insulin resistance. To address this, mice with muscle-specific overexpression of SIRT1 (mOX) and wild-type (WT) littermates were fed a control diet (10% calories from fat) or HFD (60% of calories from fat) for 12 wk. Magnetic resonance imaging and indirect calorimetry were used to measure body composition and energy expenditure, respectively. Whole body glucose metabolism was assessed by oral glucose tolerance test, and insulin-stimulated glucose uptake was measured at a physiological insulin concentration in isolated soleus and extensor digitorum longus muscles. Although SIRT1 was significantly overexpressed in muscle of mOX vs. WT mice, body weight and percent body fat were similarly increased by HFD for both genotypes, and energy expenditure was unaffected by diet or genotype. Importantly, impairments in glucose tolerance and insulin-mediated activation of glucose uptake in skeletal muscle that occurred with HFD feeding were not prevented in mOX mice. In contrast, mOX mice showed enhanced postischemic cardiac functional recovery compared with WT mice, confirming the physiological functionality of the SIRT1 transgene in this mouse model. Together, these results demonstrate that activation of SIRT1 in skeletal muscle alone does not prevent HFD-induced glucose intolerance, weight gain, or insulin resistance.
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Affiliation(s)
- Amanda T White
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, California; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California
| | - Andrew Philp
- School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Edgbaston, United Kingdom
| | - Heidi N Fridolfsson
- Department of Anesthesiology, University of California San Diego, La Jolla, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Jan M Schilling
- Department of Anesthesiology, University of California San Diego, La Jolla, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Anne N Murphy
- Department of Pharmacology, University of California San Diego, La Jolla, California
| | - D Lee Hamilton
- Health and Exercise Sciences Research Group, School of Sport, University of Stirling, Stirling, United Kingdom; and
| | - Carrie E McCurdy
- Department of Human Physiology, University of Oregon, Eugene, Oregon
| | - Hemal H Patel
- Department of Anesthesiology, University of California San Diego, La Jolla, California; Veterans Affairs San Diego Healthcare System, San Diego, California
| | - Simon Schenk
- Department of Orthopaedic Surgery, University of California San Diego, La Jolla, California; Biomedical Sciences Graduate Program, University of California San Diego, La Jolla, California;
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60
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Lee J, Hong SW, Park SE, Rhee EJ, Park CY, Oh KW, Park SW, Lee WY. Exendin-4 regulates lipid metabolism and fibroblast growth factor 21 in hepatic steatosis. Metabolism 2014; 63:1041-8. [PMID: 24933399 DOI: 10.1016/j.metabol.2014.04.011] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 04/17/2014] [Accepted: 04/29/2014] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Hepatokine fibroblast growth factor (FGF) 21 takes part in the regulation of lipid metabolism in the liver and adipose tissue. We investigated whether exendin-4 regulates the expression of FGF21 in the liver, and whether the effects of exendin-4 on the regulation of FGF21 expression are mediated via silent mating type information regulation 2 homolog (SIRT) 1 or SIRT6. MATERIALS/METHODS The C57BL/6J mice were fed a low fat diet, high fat diet, or high fat diet with 1 nmol/kg/day exendin-4 intraperitoneal injection for 10 weeks. HepG2 used in vitro study was treated with palmitic aicd (0.4 mM) with or without exendin-4 (100 nM) and FGF21 (50 nM) for 24 hours. The change of FGF21 and its receptors expression by exendin-4 were measured using quantitative real-time RT-PCR and Western blot. The intracellular lipid content in HepG2 cells was evaluated by Oil Red O staining. Inhibition of FGF21, SIRT1 and SIRT6, by 10 nM siRNA was performed to establish the signaling pathway of exendin-4 action in hepatic lipid metabolism. RESULTS Exendin-4 increased the expression of FGF21 and its receptors in high fat diet-induced obese mice. In addition, recombinant FGF21 treatment reduced lipid content in palmitic acid-treated HepG2 cells. We also observed significantly decreased expression of peroxisomal proliferator-activated receptor (PPAR) α and medium-chain acyl-coenzyme A dehydrogenase (MCAD) in hepatocytes transfected with FGF21 siRNA. In cells treated with exendin-4, inhibition of SIRT1, but not SIRT6, by siRNA significantly repressed the expression of FGF21 mRNA, whereas decreased SIRT1 expression by inhibition of FGF21 was not observed. CONCLUSIONS These data suggest that exendin-4 could improve fatty liver by increasing SIRT1-mediated FGF21.
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Affiliation(s)
- Jinmi Lee
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Seok-Woo Hong
- Institute of Medical Research, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Se Eun Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Eun-Jung Rhee
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Cheol-Young Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Ki-Won Oh
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Sung-Woo Park
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea
| | - Won-Young Lee
- Department of Endocrinology and Metabolism, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 110-746, Republic of Korea.
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