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Wang D, Zhao H, Deng C, Lei W, Ren J, Zhang S, Yang W, Lu C, Tian Y, Chen Y, Qiu Y, Meng L, Yang Y. Sulfide-modified nanoscale zero-valent iron as a novel therapeutic remedy for septic myocardial injury. J Adv Res 2024; 55:145-158. [PMID: 36801383 PMCID: PMC10770114 DOI: 10.1016/j.jare.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 01/30/2023] [Accepted: 02/12/2023] [Indexed: 02/18/2023] Open
Abstract
INTRODUCTION Myocardial injury is a serious complication in sepsis with high mortality. Zero-valent iron nanoparticles (nanoFe) displayed novel roles in cecal ligation and puncture (CLP)-induced septic mouse model. Nonetheless, its high reactivity makes it difficult for long-term storage. OBJECTIVES To overcome the obstacle and improve therapeutic efficiency, a surface passivation of nanoFe was designed using sodium sulfide. METHODS We prepared iron sulfide nanoclusters and constructed CLP mouse models. Then the effect of sulfide-modified nanoscale zero-valent iron (S-nanoFe) on the survival rate, blood routine parameters, blood biochemical parameters, cardiac function, and pathological indicators of myocardium was observed. RNA-seq was used to further explore the comprehensive protective mechanisms of S-nanoFe. Finally, the stability of S-nanoFe-1d and S-nanoFe-30 d, together with the therapeutic efficacy of sepsis between S-nanoFe and nanoFe was compared. RESULTS The results revealed that S-nanoFe significantly inhibited the growth of bacteria and exerted a protective role against septic myocardial injury. S-nanoFe treatment activated AMPK signaling and ameliorated several CLP-induced pathological processes including myocardial inflammation, oxidative stress, mitochondrial dysfunction. RNA-seq analysis further clarified the comprehensive myocardial protective mechanisms of S-nanoFe against septic injury. Importantly, S-nanoFe had a good stability and a comparable protective efficacy to nanoFe. CONCLUSIONS The surface vulcanization strategy for nanoFe has a significant protective role against sepsis and septic myocardial injury. This study provides an alternative strategy for overcoming sepsis and septic myocardial injury and opens up possibilities for the development of nanoparticle in infectious diseases.
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Affiliation(s)
- Daquan Wang
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; School of Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, 710049, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Huadong Zhao
- Department of General Surgery, Tangdu Hospital, The Airforce Medical University, 1 Xinsi Road, Xi'an, 710038, China
| | - Chao Deng
- Department of Cardiovascular Surgery, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Wangrui Lei
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Jun Ren
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China; Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Shaofei Zhang
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Wenwen Yang
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Chenxi Lu
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Ye Tian
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China
| | - Ying Chen
- Department of Hematology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Yao Qiu
- School of Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, 710049, Xi'an, China
| | - Lingjie Meng
- School of Chemistry, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi'an Jiaotong University, 710049, Xi'an, China.
| | - Yang Yang
- Deparment of Neurology, Xi'an No.3 Hospital, The Affiliated Hospital of Northwest University. Faculty of Life Sciences and Medicine, Northwest University, Xi'an, China; Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Faculty of Life Sciences and Medicine, Northwest University, Xi'an, 710069, China.
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Yu L, Gao Y, Aaron N, Qiang L. A glimpse of the connection between PPARγ and macrophage. Front Pharmacol 2023; 14:1254317. [PMID: 37701041 PMCID: PMC10493289 DOI: 10.3389/fphar.2023.1254317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 07/31/2023] [Indexed: 09/14/2023] Open
Abstract
Nuclear receptors are ligand-regulated transcription factors that regulate vast cellular activities and serve as an important class of drug targets. Among them, peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor family and have been extensively studied for their roles in metabolism, differentiation, development, and cancer, among others. Recently, there has been considerable interest in understanding and defining the function of PPARs and their agonists in regulating innate and adaptive immune responses and their pharmacological potential in combating chronic inflammatory diseases. In this review, we focus on emerging evidence for the potential role of PPARγ in macrophage biology, which is the prior innate immune executive in metabolic and tissue homeostasis. We also discuss the role of PPARγ as a regulator of macrophage function in inflammatory diseases. Lastly, we discuss the possible application of PPARγ antagonists in metabolic pathologies.
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Affiliation(s)
- Lexiang Yu
- Naomi Berrie Diabetes Center, Columbia University, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
| | - Yuen Gao
- Department of Physiology, Michigan State University, East Lansing, MI, United States
| | - Nicole Aaron
- Naomi Berrie Diabetes Center, Columbia University, New York, NY, United States
- Department of Molecular Pharmacology and Therapeutics, Columbia University, New York, NY, United States
| | - Li Qiang
- Naomi Berrie Diabetes Center, Columbia University, New York, NY, United States
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, United States
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Sears B, Saha AK. Dietary Control of Inflammation and Resolution. Front Nutr 2021; 8:709435. [PMID: 34447777 PMCID: PMC8382877 DOI: 10.3389/fnut.2021.709435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Accepted: 07/13/2021] [Indexed: 12/18/2022] Open
Abstract
The healing of any injury requires a dynamic balance of initiation and resolution of inflammation. This hypothesis-generating review presents an overview of the various nutrients that can act as signaling agents to modify the metabolic responses essential for the optimal healing of injury-induced inflammation. In this hypothesis-generating review, we describe a defined nutritional program consisting of an integrated interaction of a calorie-restricted anti-inflammatory diet coupled with adequate levels of omega-3 fatty acids and sufficient levels of dietary polyphenols that can be used in clinical trials to treat conditions associated with insulin resistance. Each dietary intervention works in an orchestrated systems-based approach to reduce, resolve, and repair the tissue damage caused by any inflammation-inducing injury. The orchestration of these specific nutrients and their signaling metabolites to facilitate healing is termed the Resolution Response. The final stage of the Resolution Response is the activation of intracellular 5' adenosine monophosphate-activated protein kinase (AMPK), which is necessary to repair tissue damaged by the initial injury-induced inflammation. The dietary optimization of the Resolution Response can be personalized to the individual by using standard blood markers. Once each of those markers is in their appropriate ranges, activation of intracellular AMPK will be facilitated. Finally, we outline how the resulting activation of AMPK will affect a diverse number of other intercellular signaling systems leading to an extended healthspan.
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Affiliation(s)
- Barry Sears
- Inflammation Research Foundation, Peabody, MA, United States
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Yoon SY, Yu JS, Hwang JY, So HM, Seo SO, Kim JK, Jang TS, Chung SJ, Kim KH. Phloridzin Acts as an Inhibitor of Protein-Tyrosine Phosphatase MEG2 Relevant to Insulin Resistance. Molecules 2021; 26:molecules26061612. [PMID: 33799458 PMCID: PMC7998658 DOI: 10.3390/molecules26061612] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/06/2021] [Accepted: 03/07/2021] [Indexed: 11/16/2022] Open
Abstract
Inhibition of the megakaryocyte protein tyrosine phosphatase 2 (PTP-MEG2, also named PTPN9) activity has been shown to be a potential therapeutic strategy for the treatment of type 2 diabetes. Previously, we reported that PTP-MEG2 knockdown enhances adenosine monophosphate activated protein kinase (AMPK) phosphorylation, suggesting that PTP-MEG2 may be a potential antidiabetic target. In this study, we found that phloridzin, isolated from Ulmus davidiana var. japonica, inhibits the catalytic activity of PTP-MEG2 (half-inhibitory concentration, IC50 = 32 ± 1.06 μM) in vitro, indicating that it could be a potential antidiabetic drug candidate. Importantly, phloridzin stimulated glucose uptake by differentiated 3T3-L1 adipocytes and C2C12 muscle cells compared to that by the control cells. Moreover, phloridzin led to the enhanced phosphorylation of AMPK and Akt relevant to increased insulin sensitivity. Importantly, phloridzin attenuated palmitate-induced insulin resistance in C2C12 muscle cells. We also found that phloridzin did not accelerate adipocyte differentiation, suggesting that phloridzin improves insulin sensitivity without significant lipid accumulation. Taken together, our results demonstrate that phloridzin, an inhibitor of PTP-MEG2, stimulates glucose uptake through the activation of both AMPK and Akt signaling pathways. These results strongly suggest that phloridzin could be used as a potential therapeutic candidate for the treatment of type 2 diabetes.
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Affiliation(s)
- Sun-Young Yoon
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
- Department of Cosmetic Science, Kwangju Women’s University, Gwangju 62396, Korea
| | - Jae Sik Yu
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
| | - Ji Young Hwang
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
| | - Hae Min So
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
| | - Seung Oh Seo
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
| | - Jung Kyu Kim
- School of Chemical Engineering, Sungkyunkwan University, Suwon 16419, Korea;
| | - Tae Su Jang
- Department of Medicine, Dankook University, Cheonan, Chungnam 31116, Korea;
| | - Sang J. Chung
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
- Correspondence: (S.J.C.); (K.H.K.); Tel.: +82-31-290-7703 (S.J.C.); +82-31-290-7700 (K.H.K.)
| | - Ki Hyun Kim
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Korea; (S.-Y.Y.); (J.S.Y.); (J.Y.H.); (H.M.S.); (S.O.S.)
- Correspondence: (S.J.C.); (K.H.K.); Tel.: +82-31-290-7703 (S.J.C.); +82-31-290-7700 (K.H.K.)
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Peroxisome Proliferator-Activated Receptors as Molecular Links between Caloric Restriction and Circadian Rhythm. Nutrients 2020; 12:nu12113476. [PMID: 33198317 PMCID: PMC7696073 DOI: 10.3390/nu12113476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Revised: 11/04/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
The circadian rhythm plays a chief role in the adaptation of all bodily processes to internal and environmental changes on the daily basis. Next to light/dark phases, feeding patterns constitute the most essential element entraining daily oscillations, and therefore, timely and appropriate restrictive diets have a great capacity to restore the circadian rhythm. One of the restrictive nutritional approaches, caloric restriction (CR) achieves stunning results in extending health span and life span via coordinated changes in multiple biological functions from the molecular, cellular, to the whole-body levels. The main molecular pathways affected by CR include mTOR, insulin signaling, AMPK, and sirtuins. Members of the family of nuclear receptors, the three peroxisome proliferator-activated receptors (PPARs), PPARα, PPARβ/δ, and PPARγ take part in the modulation of these pathways. In this non-systematic review, we describe the molecular interconnection between circadian rhythm, CR-associated pathways, and PPARs. Further, we identify a link between circadian rhythm and the outcomes of CR on the whole-body level including oxidative stress, inflammation, and aging. Since PPARs contribute to many changes triggered by CR, we discuss the potential involvement of PPARs in bridging CR and circadian rhythm.
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Rogacka D, Audzeyenka I, Piwkowska A. Regulation of podocytes function by AMP-activated protein kinase. Arch Biochem Biophys 2020; 692:108541. [PMID: 32781053 DOI: 10.1016/j.abb.2020.108541] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/23/2020] [Accepted: 08/06/2020] [Indexed: 01/08/2023]
Abstract
Podocytes are unique, highly specialized, terminally differentiated cells that form an essential, integral part of the glomerular filter. These cells limit the outside border of the glomerular basement membrane, forming a tight barrier that prevents significant protein loss from the capillary space. The slit diaphragm formed by podocytes is crucial for maintaining glomerular integrity and function. They are the target of injury in many glomerular diseases, including hypertension and diabetes mellitus. Accumulating studies have revealed that AMP-activated protein kinase (AMPK), an essential cellular energy sensor, might play a fundamental role in regulating podocyte metabolism and function. AMPK participates in insulin signaling, therefore controls glucose uptake and podocytes insulin sensitivity. It is also involved in insulin-dependent cytoskeleton reorganization in podocytes, mediating glomerular albumin permeability. AMPK plays an important role in the regulation of autophagy/apoptosis processes, which influence podocytes viability. The present review aimed to highlight the molecular mechanisms associated with AMPK that are involved in the regulation of podocyte function in health and disease states.
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Affiliation(s)
- Dorota Rogacka
- Mossakowski Medical Research Centre Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Wita Stwosza 63, 80-308, Gdansk, Poland; University of Gdansk, Faculty of Chemistry, Department of Molecular Biotechnology, Wita Stwosza 63, 80-308, Gdansk, Poland.
| | - Irena Audzeyenka
- Mossakowski Medical Research Centre Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Wita Stwosza 63, 80-308, Gdansk, Poland; University of Gdansk, Faculty of Chemistry, Department of Molecular Biotechnology, Wita Stwosza 63, 80-308, Gdansk, Poland.
| | - Agnieszka Piwkowska
- Mossakowski Medical Research Centre Polish Academy of Sciences, Laboratory of Molecular and Cellular Nephrology, Wita Stwosza 63, 80-308, Gdansk, Poland; University of Gdansk, Faculty of Chemistry, Department of Molecular Biotechnology, Wita Stwosza 63, 80-308, Gdansk, Poland.
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Peroxisome Proliferator-Activated Receptors and Caloric Restriction-Common Pathways Affecting Metabolism, Health, and Longevity. Cells 2020; 9:cells9071708. [PMID: 32708786 PMCID: PMC7407644 DOI: 10.3390/cells9071708] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/14/2020] [Accepted: 07/14/2020] [Indexed: 02/06/2023] Open
Abstract
Caloric restriction (CR) is a traditional but scientifically verified approach to promoting health and increasing lifespan. CR exerts its effects through multiple molecular pathways that trigger major metabolic adaptations. It influences key nutrient and energy-sensing pathways including mammalian target of rapamycin, Sirtuin 1, AMP-activated protein kinase, and insulin signaling, ultimately resulting in reductions in basic metabolic rate, inflammation, and oxidative stress, as well as increased autophagy and mitochondrial efficiency. CR shares multiple overlapping pathways with peroxisome proliferator-activated receptors (PPARs), particularly in energy metabolism and inflammation. Consequently, several lines of evidence suggest that PPARs might be indispensable for beneficial outcomes related to CR. In this review, we present the available evidence for the interconnection between CR and PPARs, highlighting their shared pathways and analyzing their interaction. We also discuss the possible contributions of PPARs to the effects of CR on whole organism outcomes.
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Ahmad B, Serpell CJ, Fong IL, Wong EH. Molecular Mechanisms of Adipogenesis: The Anti-adipogenic Role of AMP-Activated Protein Kinase. Front Mol Biosci 2020; 7:76. [PMID: 32457917 PMCID: PMC7226927 DOI: 10.3389/fmolb.2020.00076] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/03/2020] [Indexed: 12/24/2022] Open
Abstract
Obesity is now a widespread disorder, and its prevalence has become a critical concern worldwide, due to its association with common co-morbidities like cancer, cardiovascular diseases and diabetes. Adipose tissue is an endocrine organ and therefore plays a critical role in the survival of an individual, but its dysfunction or excess is directly linked to obesity. The journey from multipotent mesenchymal stem cells to the formation of mature adipocytes is a well-orchestrated program which requires the expression of several genes, their transcriptional factors, and signaling intermediates from numerous pathways. Understanding all the intricacies of adipogenesis is vital if we are to counter the current epidemic of obesity because the limited understanding of these intricacies is the main barrier to the development of potent therapeutic strategies against obesity. In particular, AMP-Activated Protein Kinase (AMPK) plays a crucial role in regulating adipogenesis – it is arguably the central cellular energy regulation protein of the body. Since AMPK promotes the development of brown adipose tissue over that of white adipose tissue, special attention has been given to its role in adipose tissue development in recent years. In this review, we describe the molecular mechanisms involved in adipogenesis, the role of signaling pathways and the substantial role of activated AMPK in the inhibition of adiposity, concluding with observations which will support the development of novel chemotherapies against obesity epidemics.
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Affiliation(s)
- Bilal Ahmad
- School of Biosciences, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Malaysia
| | | | - Isabel Lim Fong
- Department of Paraclinical Sciences, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak, Kota Samarahan, Malaysia
| | - Eng Hwa Wong
- School of Medicine, Faculty of Health and Medical Sciences, Taylor's University, Subang Jaya, Malaysia
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Li X, Wang YX, Shi P, Liu YP, Li T, Liu SQ, Wang CJ, Wang LX, Cao Y. Icariin treatment reduces blood glucose levels in type 2 diabetic rats and protects pancreatic function. Exp Ther Med 2020; 19:2690-2696. [PMID: 32256750 PMCID: PMC7086278 DOI: 10.3892/etm.2020.8490] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 01/13/2020] [Indexed: 12/22/2022] Open
Abstract
Icariin, a flavonoid isolated from traditional oriental herbal medicines, has been demonstrated to exhibit several health benefits in animal models and in humans. The aim of the present study was to investigate the effect of Icariin on hyperglycemia in type 2 diabetes mellitus (T2DM) in rats. A model of diabetes was established in 50 Sprague Dawley rats using a high-sugar and high-fat diet and peritoneal injection of streptozotocin. Diabetic rats were divided into five groups: Diabetic control; metformin; and rats treated with three different doses of Icariin, 5, 10 and 20 mg/kg. Body weight and blood glucose levels were measured, and serum adiponectin levels, expression of phospho-AMP mediated protein kinase (p-AMPK) and glucose transporter isoform 4 (GLUT-4) were measured using ELISA, Realtime PCR and western blotting, respectively. Diabetic rats without drug treatment exhibited reduced body weight, increased blood glucose levels and decreased the number of islets. In T2DM rats treated with 10 or 20 mg/kg Icariin, the blood glucose levels were reduced, whereas serum adiponectin levels were not affected. Additionally, the mRNA and protein expression levels of p-AMPK and GLUT-4 protein were increased in the T2DM rats treated with Icariin. In conclusion, in the diabetes rat model, Icariin alleviated the severity of diabetes, and the effects may be associated with reduction of hyperglycemia by activating an AMPK/GLUT-4 pathway.
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Affiliation(s)
- Xin Li
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yun-Xiao Wang
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Ping Shi
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Yan-Ping Liu
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Ting Li
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Shu-Qin Liu
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Chen-Jing Wang
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
| | - Le-Xin Wang
- Department of Cardiology, Liaocheng People's Hospital, Liaocheng, Shandong 252000, P.R. China.,School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales 2650, Australia
| | - Yu Cao
- Office of Drug Clinical Trial Management, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266003, P.R. China
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Lu Q, Li X, Liu J, Sun X, Rousselle T, Ren D, Tong N, Li J. AMPK is associated with the beneficial effects of antidiabetic agents on cardiovascular diseases. Biosci Rep 2019; 39:BSR20181995. [PMID: 30710062 PMCID: PMC6379227 DOI: 10.1042/bsr20181995] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Revised: 01/21/2019] [Accepted: 01/31/2019] [Indexed: 02/06/2023] Open
Abstract
Diabetics have higher morbidity and mortality in cardiovascular disease (CVD). A variety of antidiabetic agents are available for clinical choice. Cardiovascular (CV) safety assessment of these agents is crucial in addition to hypoglycemic effect before clinical prescription. Adenosine 5'-monophosphate-activated protein kinase (AMPK) is an important cell energy sensor, which plays an important role in regulating myocardial energy metabolism, reducing ischemia and ischemia/reperfusion (I/R) injury, improving heart failure (HF) and ventricular remodeling, ameliorating vascular endothelial dysfunction, antichronic inflammation, anti-apoptosis, and regulating autophagy. In this review, we summarized the effects of antidiabetic agents to CVD according to basic and clinical research evidence and put emphasis on whether these agents can play roles in CV system through AMPK-dependent signaling pathways. Metformin has displayed definite CV benefits related to AMPK. Sodium-glucose cotransporter 2 inhibitors also demonstrate sufficient clinical evidence for CV protection, but the mechanisms need further exploration. Glucagon-likepeptide1 analogs, dipeptidyl peptidase-4 inhibitors, α-glucosidase inhibitors and thiazolidinediones also show some AMPK-dependent CV benefits. Sulfonylureas and meglitinides may be unfavorable to CV system. AMPK is becoming a promising target for the treatment of diabetes, metabolic syndrome and CVD. But there are still some questions to be answered.
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Affiliation(s)
- Qingguo Lu
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 610041 Chengdu, China
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
| | - Xuan Li
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
| | - Jia Liu
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
- Department of Geriatrics, The First Hospital of Jilin University, 130021 Changchun, China
| | - Xiaodong Sun
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
- Department of Endocrinology, Affiliated Hospital of Weifang Medical University, 261000 Weifang, China
| | - Thomas Rousselle
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
| | - Di Ren
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A
| | - Nanwei Tong
- Department of Endocrinology and Metabolism, West China Hospital of Sichuan University, 610041 Chengdu, China
| | - Ji Li
- Department of Physiology and Biophysics, Mississippi Center for Heart Research, University of Mississippi Medical Center, 39216 Jackson, MS, U.S.A.
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Ida S, Murata K, Kaneko R. Effects of metformin treatment on blood leptin and ghrelin levels in patients with type 2 diabetes mellitus. J Diabetes 2017; 9:526-535. [PMID: 27380451 DOI: 10.1111/1753-0407.12445] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/26/2016] [Accepted: 06/25/2016] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND The aim of the present study was to conduct a meta-analysis of randomized controlled trials (RCTs) that investigated the effects of metformin on blood leptin and ghrelin levels in patients with type 2 diabetes mellitus (T2DM). METHODS Literature searches were performed using MEDLINE, Cochrane Controlled Trials Registry, and ClinicalTrials.gov, and RCTs that investigated the effects of metformin on blood leptin and ghrelin levels in patients with T2DM were selected. Standardized mean differences (SMDs) and 95 % confidence intervals (CIs) were calculated. RESULTS Twelve RCTs met the eligibility criteria and were included in the meta-analysis. There was no significant difference in blood leptin between the metformin and control groups (SMD 0.03; 95 % CI -0.35 %, 0.42 %; P = 0.86), although there was a significant difference in blood leptin levels between the metformin group and the group on oral antidiabetic drugs (OADs) other than metformin (SMD -0.39; 95 % CI -0.76 %, -0.01 %; P = 0.04). There were no significant differences in blood ghrelin levels. CONCLUSIONS Metformin treatment was not associated with a decrease in blood leptin levels in patients with T2DM compared with levels in patients in the control group. Moreover, metformin treatment was not associated with increases in blood ghrelin levels compared with the control and other OADs groups. However, blood leptin levels were significantly lower in the metformin compared with the other OADs group.
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Affiliation(s)
- Satoshi Ida
- Department of Diabetes and Metabolism, Ise Red Cross Hospital, Mie, Japan
| | - Kazuya Murata
- Department of Diabetes and Metabolism, Ise Red Cross Hospital, Mie, Japan
| | - Ryutaro Kaneko
- Department of Diabetes and Metabolism, Ise Red Cross Hospital, Mie, Japan
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12
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Modulation of glucose metabolism by a natural compound from Chloranthus japonicus via activation of AMP-activated protein kinase. Sci Rep 2017; 7:778. [PMID: 28396610 PMCID: PMC5429703 DOI: 10.1038/s41598-017-00925-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 03/17/2017] [Indexed: 12/25/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a key sensor and regulator of glucose metabolism. Here, we demonstrated that shizukaol F, a natural compound isolated from Chloranthus japonicus, can activate AMPK and modulate glucose metabolism both in vitro and in vivo. Shizukaol F increased glucose uptake in differentiated C2C12 myotubes by stimulating glucose transporter-4 (GLUT-4) membraned translocation. Treatment of primary mouse hepatocytes with shizukaol F decreased the expression of phosphoenolpyruvate carboxykinase 2 (PEPCK), glucose-6-phosphatase (G6Pase) and suppressed hepatic gluconeogenesis. Meanwhile, a single oral dose of shizukaol F reduced gluconeogenesis in C57BL/6 J mice. Further studies indicated that shizukaol F modulates glucose metabolism mainly by AMPKa phosphorylation activity. In addition, we also found that shizukaol F depolarizes the mitochondrial membrane and inhibits respiratory complex I, which may result in AMPK activation. Our results highlight the potential value of shizukaol F as a possible treatment of metabolic syndrome.
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13
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Yang LL, Xiao N, Liu J, Liu K, Liu B, Li P, Qi LW. Differential regulation of baicalin and scutellarin on AMPK and Akt in promoting adipose cell glucose disposal. Biochim Biophys Acta Mol Basis Dis 2016; 1863:598-606. [PMID: 27903431 DOI: 10.1016/j.bbadis.2016.11.024] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/21/2016] [Accepted: 11/24/2016] [Indexed: 12/01/2022]
Abstract
Baicalin and scutellarin, two flavonoid glucuronic acids isolated from Scutellaria baicalensis, exhibit beneficial effects on glucose homeostasis. Baicalin and scutellarin are similar in structure except scutellarin has an additional hydroxyl at composition C-4'. In this work, we observed that baicalin and scutellarin promoted glucose disposal in mice and in adipocytes. Baicalin selectively increased phosphorylation of AMP-activated kinase (AMPK), while scutellarin selectively enhanced Akt phosphorylation. Both of them increased AS160 phosphorylation and glucose uptake in basal condition. AMPK inhibitor or knockdown of AMPK by siRNA blocked baicalin-induced AS160 phosphorylation and glucose uptake, but showed no effects on scutellarin. In contrast, Akt inhibitor and knockdown of Akt with siRNA decreased scutellarin-stimulated glucose uptake but had no effects on baicalin. The molecular dynamic simulations analysis showed that the binding energy of baicalin to AMPK (-34.30kcal/mol) was more favorable than scutellarin (-21.27kcal/mol), while the binding energy of scutellarin (-29.81kcal/mol) to Akt was much more favorable than baicalin (4.04kcal/mol). Interestingly, a combined treatment with baicalin and scutellarin acted synergistically to enhance glucose uptake in adipocytes (combination index: 0.94-0.046). In conclusion, baicalin and scutellarin, though structurally similar, promoted glucose disposal in adipocytes by differential regulation on AMPK and Akt activity. Our data provide insight that multicomponent herbal medicines may act synergistically on multiple targets.
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Affiliation(s)
- Le-Le Yang
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China
| | - Na Xiao
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China
| | - Jinfeng Liu
- State Key Laboratory of Precision Spectroscopy, East China Normal University, No. 3663 North Zhongshan Road, Shanghai 200062, China
| | - Kang Liu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China
| | - Baolin Liu
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China
| | - Ping Li
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China
| | - Lian-Wen Qi
- State Key Laboratory of Natural Medicines, China Pharmaceutical University, No. 24 Tongjia Lane, Nanjing 210009, China.
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14
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Liu Y, Park JM, Chang KH, Huh HJ, Lee K, Lee MY. AMP-Activated Protein Kinase Mediates the Antiplatelet Effects of the Thiazolidinediones Rosiglitazone and Pioglitazone. Mol Pharmacol 2015; 89:313-21. [DOI: 10.1124/mol.115.102004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2015] [Accepted: 11/23/2015] [Indexed: 01/02/2023] Open
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15
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ALVIM RAFAELO, CHEUHEN MARCELR, MACHADO SILMARAR, SOUSA ANDRÉGUSTAVOP, SANTOS PAULOC. General aspects of muscle glucose uptake. ACTA ACUST UNITED AC 2015; 87:351-68. [DOI: 10.1590/0001-3765201520140225] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Accepted: 09/06/2014] [Indexed: 12/25/2022]
Abstract
Glucose uptake in peripheral tissues is dependent on the translocation of GLUT4 glucose transporters to the plasma membrane. Studies have shown the existence of two major signaling pathways that lead to the translocation of GLUT4. The first, and widely investigated, is the insulin activated signaling pathway through insulin receptor substrate-1 and phosphatidylinositol 3-kinase. The second is the insulin-independent signaling pathway, which is activated by contractions. Individuals with type 2 diabetes mellitus have reduced insulin-stimulated glucose uptake in skeletal muscle due to the phenomenon of insulin resistance. However, those individuals have normal glucose uptake during exercise. In this context, physical exercise is one of the most important interventions that stimulates glucose uptake by insulin-independent pathways, and the main molecules involved are adenosine monophosphate-activated protein kinase, nitric oxide, bradykinin, AKT, reactive oxygen species and calcium. In this review, our main aims were to highlight the different glucose uptake pathways and to report the effects of physical exercise, diet and drugs on their functioning. Lastly, with the better understanding of these pathways, it would be possible to assess, exactly and molecularly, the importance of physical exercise and diet on glucose homeostasis. Furthermore, it would be possible to assess the action of drugs that might optimize glucose uptake and consequently be an important step in controlling the blood glucose levels in diabetic patients, in addition to being important to clarify some pathways that justify the development of drugs capable of mimicking the contraction pathway.
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16
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Colca JR, McDonald WG, Kletzien RF. Mitochondrial target of thiazolidinediones. Diabetes Obes Metab 2014; 16:1048-54. [PMID: 24774061 DOI: 10.1111/dom.12308] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/17/2014] [Accepted: 04/22/2014] [Indexed: 12/11/2022]
Abstract
Insulin-sensitizing thiazolidinediones exert a pleiotropic pharmacology with therapeutic potential in a number of disease states ranging from metabolic syndrome and diabetes to neurodegeneration and cancer. A growing understanding of their mechanism of action, working from the site of their binding in the mitochondrion, provides insight into the mechanism of action of the insulin sensitizers and the reasons for their pleiotropic pharmacology. This review helps to frame the direction of future work that should be helpful in setting a new direction for the discovery and development of new, more useful therapeutic agents for metabolic disease.
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Affiliation(s)
- J R Colca
- Metabolic Solutions Development Company, Kalamazoo, MI, USA
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17
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Yang S, Luo T, Zhou H, Lv Q, Liu L, Zhang W, Gao R, Chen S, Xia W, Luo M, Cheng Q, Li Q. Rosiglitazone inhibits expression and secretion of PEDF in adipose tissue and liver of male SD rats via a PPAR-γ independent mechanism. Endocrinology 2014; 155:941-50. [PMID: 24424059 DOI: 10.1210/en.2013-1813] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pigment epithelium-derived factor (PEDF) plays an important role in insulin resistance (IR). The study aims to investigate the effect of rosiglitazone, an insulin sensitizer, on PEDF production and release both in vivo and in vitro. Male SD rats were divided into normal control group, high-fat group, and rosiglitazone group. Hyperinsulinemic euglycemic clamp was performed to evaluate insulin sensitivity. IR models of 3T3-L1 adipocytes and HepG2 cells were established by the hyperinsulinemic method. Glucose uptake was examined to validate IR of adipocytes, and phosphorylation of protein kinase B and glycogen synthesis kinase 3β were examined to validate IR of HepG2 cells. Rosiglitazone, 2-chloro-5-nitro-N-phenylbenzamide (GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ), and compound C (inhibitor of AMP-activated protein kinase [AMPK]) were used for the in vitro intervention. In vivo, the high-fat group showed increased serum PEDF levels, which negatively correlated with insulin sensitivity, whereas the rosiglitazone treatment decreased the serum PEDF and down-regulated PEDF expression in fat and liver of the obese rats, concomitant with significantly enhanced insulin sensitivity. In vitro, the IR cells showed increased PEDF secretion and expression, whereas rosiglitazone lowered PEDF secretion and expression, accompanied with increased insulin sensitivity. Interestingly, combination with 2-chloro-5-nitro-N-phenylbenzamide did not influence the effect of rosiglitazone on PEDF. However, rosiglitazone stimulated AMPK phosphorylation in fat and liver of the obese rats, whereas in vitro, when combined with compound C, the effect of rosiglitazone on PEDF was abrogated. In summary, rosiglitazone inhibits the expression and secretion of PEDF in fat and liver via promoting AMPK phosphorylation rather than peroxisome proliferator-activated receptor-γ, and changes of PEDF induced by rosiglitazone are closely associated with IR improvement.
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Affiliation(s)
- Shumin Yang
- Department of Endocrinology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China
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18
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Yoneda M, Guo Y, Ono H, Nakatsu Y, Zhang J, Cui X, Iwashita M, Kumamoto S, Tsuchiya Y, Sakoda H, Fujishiro M, Kushiyama A, Koketsu Y, Kikuchi T, Kamata H, Nishimura F, Asano T. Decreased SIRT1 expression and LKB1 phosphorylation occur with long-term high-fat diet feeding, in addition to AMPK phosphorylation impairment in the early phase. Obes Res Clin Pract 2013; 4:e163-246. [PMID: 24345663 DOI: 10.1016/j.orcp.2010.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2009] [Revised: 01/19/2010] [Accepted: 02/01/2010] [Indexed: 12/25/2022]
Abstract
SUMMARY AIMS Energy sensing systems including AMPK and SIRT1 play important roles in the regulation of hepatic gluconeogenesis and fatty acid oxidation. In this study, we investigated how hepatic LKB1-AMPK signaling and SIRT1 expression are altered after 2 or 8 weeks of HFD feeding. METHODS The livers of male mice fed a HFD or a standard diet for 2 or 8 weeks were removed. The expression and phosphorylation levels of LKB1, AMPK, ACC and TORC2, and SIRT1 expression levels were examined by immunoblotting. RESULTS In mice fed a HFD for 2 weeks, the phosphorylations of AMPKα and ACC were decreased without significant alterations in LKB1 phosphorylation or SIRT1 protein levels, while TORC2 protein levels were increased. In mice fed a HFD for 8 weeks, marked reductions in LKB1 phosphorylation and SIRT1 protein amount were observed in addition to the decreased phosphorylations of AMPKα and ACC. CONCLUSIONS The mechanisms underlying impaired energy sensing signaling differ with the duration of HFD feeding. In the early phase of HFD feeding, LKB1 and SIRT1 were not impaired, while in the later phase of HFD feeding, decreased SIRT1 expression and LKB1 phosphorylation may be involved in the development of severe glucose and lipid intolerance.
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Affiliation(s)
- Masayasu Yoneda
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Ying Guo
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Haruya Ono
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Yusuke Nakatsu
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Jun Zhang
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Xinglong Cui
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Misaki Iwashita
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Sonoko Kumamoto
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Yoshihiro Tsuchiya
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Hideyuki Sakoda
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Midori Fujishiro
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Akifumi Kushiyama
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Yuko Koketsu
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Takako Kikuchi
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Hideaki Kamata
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Fusanori Nishimura
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan
| | - Tomoichiro Asano
- Department of Medical Chemistry, Division of Molecular Medical Science, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
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19
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Liu Y, Yan X, Mao G, Fang L, Zhao B, Liu Y, Tang H, Wang N. Metabonomic profiling revealed an alteration in purine nucleotide metabolism associated with cardiac hypertrophy in rats treated with thiazolidinediones. J Proteome Res 2013; 12:5634-41. [PMID: 24164426 DOI: 10.1021/pr400587y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Thiazolidinediones (TZDs) including rosiglitazone (RSG) and pioglitazone (PIO) are synthetic agonists selective for peroxisome proliferator-activated receptor-γ (PPARγ) and have been clinically used to treat type-II diabetes as insulin sensitizers. Recent meta-analyses have shown that TZDs are associated with an increased risk for the development of heart failure. To elucidate the mechanism underlying such a cardiac adverse effect, we used a (1)H NMR-based approach to examine the metabonomic profiles in the cardiac tissues treated with RSG (15 mg/kg body weight/day) or PIO (45 mg/kg/day) for 4 weeks and found that the TZD treatments resulted in a significantly altered metabolic profile in hearts, which was associated with cardiac hypertrophy. Multivariate analysis demonstrated that TZDs led to an accumulation in adenosine monophosphate (AMP) and a depletion of inosine. Consistently, AMP kinase, a signal pathway sensitive to the change in the intracellular concentrations of AMP, was activated in the cardiac tissues from the TZDs-treated rats. Quantitative real-time reverse-transcriptase polymerase chain reaction showed a significant induction of the genes involved in the de novo synthesis of purine nucleotide but a reduction of those for the catabolism. Furthermore, the putative PPAR-responsive elements were identified in the 5'-flanking regions of the TZD-up-regulated genes such as adenylosuccinate synthase gene (Adss) and phosphoribosl pyrophosphate synthetase 1 (Prps1), and the binding of PPARγ to these motifs was confirmed by using chromatin immunoprecipitation assay. In conclusion, these results demonstrated that TZDs induced alterations in purine nucleotide metabolism in rat hearts via transcriptional regulation of the PPARγ-target genes, which may play an important role in the development of cardiac hypertrophy associated with TZDs.
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Affiliation(s)
- Yan Liu
- Institute of Cardiovascular Science, Peking University Health Science Center , 38 Xueyuan Road, Beijing 100191, China
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20
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Colca JR, Tanis SP, McDonald WG, Kletzien RF. Insulin sensitizers in 2013: new insights for the development of novel therapeutic agents to treat metabolic diseases. Expert Opin Investig Drugs 2013; 23:1-7. [DOI: 10.1517/13543784.2013.839659] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Jerry R Colca
- Metabolic Solutions Development Company,
161 E. Michigan Ave, Kalamazoo, 49007, USA
| | - Steven P Tanis
- PharmaChem Consulting LLC,
1750 Oriole Ct, Carlsbad, 92011, United States
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21
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O'Neill HM, Holloway GP, Steinberg GR. AMPK regulation of fatty acid metabolism and mitochondrial biogenesis: implications for obesity. Mol Cell Endocrinol 2013; 366:135-51. [PMID: 22750049 DOI: 10.1016/j.mce.2012.06.019] [Citation(s) in RCA: 241] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 03/13/2012] [Accepted: 06/21/2012] [Indexed: 12/25/2022]
Abstract
Skeletal muscle plays an important role in regulating whole-body energy expenditure given it is a major site for glucose and lipid oxidation. Obesity and type 2 diabetes are causally linked through their association with skeletal muscle insulin resistance, while conversely exercise is known to improve whole body glucose homeostasis simultaneously with muscle insulin sensitivity. Exercise activates skeletal muscle AMP-activated protein kinase (AMPK). AMPK plays a role in regulating exercise capacity, skeletal muscle mitochondrial content and contraction-stimulated glucose uptake. Skeletal muscle AMPK is also thought to be important for regulating fatty acid metabolism; however, direct genetic evidence in this area is currently lacking. This review will discuss the current paradigms regarding the influence of AMPK in regulating skeletal muscle fatty acid metabolism and mitochondrial biogenesis at rest and during exercise, and highlight the potential implications in the development of insulin resistance.
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Affiliation(s)
- Hayley M O'Neill
- University of Melbourne, Department of Medicine, St. Vincent's Institute of Medical Research, Melbourne, Victoria, Australia.
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22
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Cao S, Li B, Yi X, Chang B, Zhu B, Lian Z, Zhang Z, Zhao G, Liu H, Zhang H. Effects of exercise on AMPK signaling and downstream components to PI3K in rat with type 2 diabetes. PLoS One 2012; 7:e51709. [PMID: 23272147 PMCID: PMC3521695 DOI: 10.1371/journal.pone.0051709] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Accepted: 11/05/2012] [Indexed: 01/31/2023] Open
Abstract
Exercise can increase skeletal muscle sensitivity to insulin, improve insulin resistance and regulate glucose homeostasis in rat models of type 2 diabetes. However, the potential mechanism remains poorly understood. In this study, we established a male Sprague–Dawley rat model of type 2 diabetes, with insulin resistance and β cell dysfunction, which was induced by a high-fat diet and low-dose streptozotocin to replicate the pathogenesis and metabolic characteristics of type 2 diabetes in humans. We also investigated the possible mechanism by which chronic and acute exercise improves metabolism, and the phosphorylation and expression of components of AMP-activated protein kinase (AMPK) and downstream components of phosphatidylinositol 3-kinase (PI3K) signaling pathways in the soleus. As a result, blood glucose, triglyceride, total cholesterol, and free fatty acid were significantly increased, whereas insulin level progressively declined in diabetic rats. Interestingly, chronic and acute exercise reduced blood glucose, increased phosphorylation and expression of AMPKα1/2 and the isoforms AMPKα1 and AMPKα2, and decreased phosphorylation and expression of AMPK substrate, acetyl CoA carboxylase (ACC). Chronic exercise upregulated phosphorylation and expression of AMPK upstream kinase, LKB1. But acute exercise only increased LKB1 expression. In particular, exercise reversed the changes in protein kinase C (PKC)ζ/λ phosphorylation, and PKCζ phosphorylation and expression. Additionally, exercise also increased protein kinase B (PKB)/Akt1, Akt2 and GLUT4 expression, but AS160 protein expression was unchanged. Chronic exercise elevated Akt (Thr308) and (Ser473) and AS160 phosphorylation. Finally, we found that exercise increased peroxisome proliferator-activated receptor-γ coactivator 1 (PGC1) mRNA expression in the soleus of diabetic rats. These results indicate that both chronic and acute exercise influence the phosphorylation and expression of components of the AMPK and downstream to PIK3 (aPKC, Akt), and improve GLUT4 trafficking in skeletal muscle. These data help explain the mechanism how exercise regulates glucose homeostasis in diabetic rats.
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Affiliation(s)
- Shicheng Cao
- Department of Sport Medicine, College of Basic Medical Sciences, China Medical University, Shenyang, Liaoning Province, China.
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Ushijima K, Takuma M, Ando H, Ishikawa-Kobayashi E, Nozawa M, Maekawa T, Shiga T, Fujimura A. Effects of telmisartan and valsartan on insulin sensitivity in obese diabetic mice. Eur J Pharmacol 2012. [PMID: 23195328 DOI: 10.1016/j.ejphar.2012.11.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Telmisartan and valsartan have angiotensin II receptor blocking activity. Because telmisartan has also an agonistic action for peroxisome proliferators-activator receptor (PPAR)-γ, it is speculated that an effect of telmisartan on insulin sensitivity is different from that of valsartan, which lacks of PPAR-γ agonistic activity. To address the issue, effects of telmisartan and valsartan on insulin sensitivity, adipocytokines and PPAR-γ target genes were evaluated in obese diabetic mice. KK-A(y) mice were treated with telmisartan (5mg/kg) and valsartan (15 mg/kg), once daily for 3 weeks. Insulin tolerance test was performed on day 14, and plasma adiponectin concentration and mRNA expression levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in adipose tissues were measured on day 21. Time-course of plasma glucose level after the injection of insulin in mice with telmisartan was not significantly different from that of animals with valsartan. In addition, PPAR-γ antagonist did not diminished the improvement of insulin sensitivity by telmisartan. Telmisartan and valsartan elevated plasma adiponectin concentration and suppressed the mRNA expressions of TNF-α and IL-6 in adipose tissues. These variables of the telmisartan- and valsartan-treated groups did not significantly differ. Influence of telmisartan on the PPAR-γ target genes (ap2 and fatty acid synthase) mRNA expressions was not detected in adipose tissues under the present condition. These data suggest that the effect of telmisartan on insulin sensitivity is similar to that of valsartan, and a role of PPAR-γ-mediated stimuli is small in the telmisartan-induced improvement of insulin sensitivity.
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Affiliation(s)
- Kentarou Ushijima
- Division of Clinical Pharmacology, Department of Pharmacology, Jichi Medical University, Shimotsuke, Tochigi 329-0498, Japan
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Klaus S, Keipert S, Rossmeisl M, Kopecky J. Augmenting energy expenditure by mitochondrial uncoupling: a role of AMP-activated protein kinase. GENES AND NUTRITION 2011; 7:369-86. [PMID: 22139637 DOI: 10.1007/s12263-011-0260-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 11/18/2011] [Indexed: 11/28/2022]
Abstract
Strategies to prevent and treat obesity aim to decrease energy intake and/or increase energy expenditure. Regarding the increase of energy expenditure, two key intracellular targets may be considered (1) mitochondrial oxidative phosphorylation, the major site of ATP production, and (2) AMP-activated protein kinase (AMPK), the master regulator of cellular energy homeostasis. Experiments performed mainly in transgenic mice revealed a possibility to ameliorate obesity and associated disorders by mitochondrial uncoupling in metabolically relevant tissues, especially in white adipose tissue (WAT), skeletal muscle (SM), and liver. Thus, ectopic expression of brown fat-specific mitochondrial uncoupling protein 1 (UCP1) elicited major metabolic effects both at the cellular/tissue level and at the whole-body level. In addition to expected increases in energy expenditure, surprisingly complex phenotypic effects were detected. The consequences of mitochondrial uncoupling in WAT and SM are not identical, showing robust and stable obesity resistance accompanied by improvement of lipid metabolism in the case of ectopic UCP1 in WAT, while preservation of insulin sensitivity in the context of high-fat feeding represents the major outcome of muscle UCP1 expression. These complex responses could be largely explained by tissue-specific activation of AMPK, triggered by a depression of cellular energy charge. Experimental data support the idea that (1) while being always activated in response to mitochondrial uncoupling and compromised intracellular energy status in general, AMPK could augment energy expenditure and mediate local as well as whole-body effects; and (2) activation of AMPK alone does not lead to induction of energy expenditure and weight reduction.
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Affiliation(s)
- Susanne Klaus
- German Institute of Human Nutrition, Arthur-Scheunert-Allee 114-116, 14558, Nuthetal, Germany
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Ye JM, Tid-Ang J, Turner N, Zeng XY, Li HY, Cooney GJ, Wulff EM, Sauerberg P, Kraegen EW. PPARδ agonists have opposing effects on insulin resistance in high fat-fed rats and mice due to different metabolic responses in muscle. Br J Pharmacol 2011; 163:556-66. [PMID: 21265823 DOI: 10.1111/j.1476-5381.2011.01240.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE The peroxisome proliferator-activated receptor (PPAR)δ has been considered a therapeutic target for diabetes and obesity through enhancement of fatty acid oxidation. The present study aimed to characterize the effects of PPARδ agonists during insulin resistance of the whole body, muscle and liver. EXPERIMENTAL APPROACH Wistar rats and C57BL/J6 mice were fed a high fat diet (HF) and then treated with PPARδ agonists NNC61-5920 and GW501516. The effects on insulin resistance were evaluated by hyperinsulinaemic clamp or glucose tolerance tests combined with glucose tracers. KEY RESULTS In HF rats, 3 weeks of treatment with NNC61-5920 reduced the glucose infusion rate (by 14%, P < 0.05) and glucose disposal into muscle (by 20-30%, P < 0.01) during hyperinsulinaemic clamp. Despite increased mRNA expression of carnitine palmitoyltransferase-1, pyruvate dehydrogenase kinase 4 and uncoupling protein 3 in muscle, plasma and muscle triglyceride levels were raised (P < 0.01). Similar metabolic effects were observed after extended treatment with NNC61-5920 and GW501516 to 6 weeks. However, HF mice treated with NNC61-5920 improved their plasma lipid profile, glucose tolerance and insulin action in muscle. In both HF rats and mice, NNC61-5920 treatment attenuated hepatic insulin resistance and decreased expression of stearoyl-CoA desaturase 1, fatty acid translocase protein CD36 and lipoprotein lipase in liver. CONCLUSIONS AND IMPLICATIONS PPARδ agonists exacerbated insulin resistance in HF rats in contrast to their beneficial effects on metabolic syndrome in HF mice. These opposing metabolic consequences result from their different effects on lipid metabolism and insulin sensitivity in skeletal muscle of these two species.
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Affiliation(s)
- Ji-Ming Ye
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, University of New South Wales, Sydney, NSW, Australia.
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Influence of a long-term high-fat diet on ghrelin secretion and ghrelin-induced food intake in rats. ACTA ACUST UNITED AC 2011; 173:60-3. [PMID: 21971115 DOI: 10.1016/j.regpep.2011.09.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Revised: 08/30/2011] [Accepted: 09/16/2011] [Indexed: 11/22/2022]
Abstract
The aims of this study were: (1) to define the extent to which a high-fat (HF) diet given on a long-term basis reduces resting plasma ghrelin (total [acyl+des-acyl]) levels and the plasma ghrelin (total) response to fasting, (2) to determine whether a chronic HF diet modifies the orexigenic activity of acyl-ghrelin, (3) whether insulin pretreatment inhibits the plasma ghrelin (total) response to fasting, and (4) the extent to which pioglitazone (PIO) treatment will increase stomach and plasma ghrelin (total) levels in rats fed a HF diet. PIO is a drug given to diabetics which improves insulin resistance. Our findings show that a chronic HF diet given for either 10 or 60 weeks exerts a persistent inhibitory effect on resting plasma ghrelin (total) levels. Additionally, the plasma ghrelin (total) elevation to overnight fasting is not altered in rats fed a HF diet on a long-term basis. A HF diet does not impair the ingestive response to acyl-ghrelin. Together, these results suggest that acyl-ghrelin serves as an important orexigenic factor. Results show that insulin pretreatment does not inhibit the plasma ghrelin (total) response to fasting suggesting that meal-induced insulin secretion does not have a role in reducing ghrelin (total) secretion. In rats fed a HF diet, PIO administration increases stomach ghrelin (total) levels. Because PIO can reduce systemic glucose and lipid levels, our findings suggest that elevated glucose and lipid levels are part of the inhibitory mechanism behind reduced ghrelin (total) secretion in rats fed a HF diet.
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Wang Q, Zhang M, Liang B, Shirwany N, Zhu Y, Zou MH. Activation of AMP-activated protein kinase is required for berberine-induced reduction of atherosclerosis in mice: the role of uncoupling protein 2. PLoS One 2011; 6:e25436. [PMID: 21980456 PMCID: PMC3181327 DOI: 10.1371/journal.pone.0025436] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 09/05/2011] [Indexed: 12/15/2022] Open
Abstract
AIMS Berberine, a botanical alkaloid purified from Coptidis rhizoma, is reported to activate the AMP-activated protein kinase (AMPK). Whether AMPK is required for the protective effects of berberine in cardiovascular diseases remains unknown. This study was designed to determine whether AMPK is required for berberine-induced reduction of oxidative stress and atherosclerosis in vivo. METHODS ApoE (ApoE⁻/⁻) mice and ApoE⁻/⁻/AMPK alpha 2⁻/⁻ mice that were fed Western diets were treated with berberine for 8 weeks. Atherosclerotic aortic lesions, expression of uncoupling protein 2 (UCP2), and markers of oxidative stress were evaluated in isolated aortas. RESULTS In ApoE⁻/⁻ mice, chronic administration of berberine significantly reduced aortic lesions, markedly reduced oxidative stress and expression of adhesion molecules in aorta, and significantly increased UCP2 levels. In contrast, in ApoE⁻/⁻/AMPK alpha 2⁻/⁻ mice, berberine had little effect on those endpoints. In cultured human umbilical vein endothelial cells (HUVECs), berberine significantly increased UCP2 mRNA and protein expression in an AMPK-dependent manner. Transfection of HUVECs with nuclear respiratory factor 1 (NRF1)-specific siRNA attenuated berberine-induced expression of UCP2, whereas transfection with control siRNA did not. Finally, berberine promoted mitochondrial biogenesis that contributed to up-regulation of UCP2 expression. CONCLUSION We conclude that berberine reduces oxidative stress and vascular inflammation, and suppresses atherogenesis via a mechanism that includes stimulation of AMPK-dependent UCP2 expression.
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Affiliation(s)
- Qilong Wang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Miao Zhang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Bin Liang
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Najeeb Shirwany
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Yi Zhu
- Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Ming-Hui Zou
- Section of Molecular Medicine, Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail:
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Morrison A, Yan X, Tong C, Li J. Acute rosiglitazone treatment is cardioprotective against ischemia-reperfusion injury by modulating AMPK, Akt, and JNK signaling in nondiabetic mice. Am J Physiol Heart Circ Physiol 2011; 301:H895-902. [DOI: 10.1152/ajpheart.00137.2011] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Rosiglitazone (RGZ), a peroxisome proliferator-activated receptor (PPAR)-γ agonist, has been demonstrated to possess cardioprotective properties during ischemia-reperfusion. However, this notion remains controversial as recent evidence has suggested an increased risk in cardiac events associated with long-term use of RGZ in patients with type 2 diabetes. In this study, we tested the hypothesis that acute RGZ treatment is beneficial during I/R by modulating cardioprotective signaling pathways in a nondiabetic mouse model. RGZ (1 μg/g) was injected intravenously via the tail vein 5 min before reperfusion. Myocardial infarction was significantly reduced in mice treated with RGZ compared with vehicle controls (8.7% ± 1.1% vs. 20.2% ± 2.5%, P < 0.05). Moreover, isolated hearts were subjected to 20 min of global, no-flow ischemia in an ex vivo heart perfusion system. Postischemic recovery was significantly improved with RGZ treatment administered at the onset of reperfusion compared with vehicle ( P < 0.001). Immunoblot analysis data revealed that the levels of both phospho-AMP-activated protein kinase (Thr172) and phospho-Akt (Ser473) were significantly upregulated when RGZ was administered 5 min before reperfusion compared with vehicle. On the other hand, inflammatory signaling [phospho-JNK (Thr183/Tyr185)] was significantly downregulated as a result of RGZ treatment compared with vehicle ( P < 0.05). Intriguingly, pretreatment with the selective PPAR-γ inhibitor GW-9662 (1 μg/g iv) 10 min before reperfusion significantly attenuated these beneficial effects of RGZ on the ischemic heart. Taken together, acute treatment with RGZ can reduce ischemic injury in a nondiabetic mouse heart via modulation of AMP-activated protein kinase, Akt, and JNK signaling pathways, which is dependent on PPAR-γ activation.
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Affiliation(s)
- Alex Morrison
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Xiaoyan Yan
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Chao Tong
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo-State University of New York, Buffalo, New York
| | - Ji Li
- Department of Pharmacology and Toxicology, School of Medicine and Biomedical Sciences, University at Buffalo-State University of New York, Buffalo, New York
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Morrison A, Li J. PPAR-γ and AMPK – Advantageous targets for myocardial ischemia/reperfusion therapy. Biochem Pharmacol 2011; 82:195-200. [DOI: 10.1016/j.bcp.2011.04.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 04/11/2011] [Accepted: 04/14/2011] [Indexed: 12/25/2022]
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Cerquetti L, Sampaoli C, Amendola D, Bucci B, Masuelli L, Marchese R, Misiti S, De Venanzi A, Poggi M, Toscano V, Stigliano A. Rosiglitazone induces autophagy in H295R and cell cycle deregulation in SW13 adrenocortical cancer cells. Exp Cell Res 2011; 317:1397-410. [DOI: 10.1016/j.yexcr.2011.02.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 02/17/2011] [Accepted: 02/25/2011] [Indexed: 10/18/2022]
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Liu IM, Tzeng TF, Liou SS. A Chinese Herbal Decoction, Dang Gui Bu Xue Tang, Prepared from Radix Astragali and Radix Angelicae sinensis, Ameliorates Insulin Resistance Induced by A High-Fructose Diet in Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2011; 2011:248231. [PMID: 19233878 PMCID: PMC3095507 DOI: 10.1093/ecam/nep004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2008] [Accepted: 01/13/2009] [Indexed: 01/28/2023]
Abstract
Dang Gui Bu Xue Tang (DBT), a Chinese medicinal decoction contains Radix Angelicae sinensis (Danggui) and Radix Astragali (Huangqi) at a ratio of 1 : 5, is used commonly for treating women's ailments. This study was conducted to explore the effects of this preparation on insulin resistance in rats fed with 6-week diet containing 60% fructose. Similar to the action of rosiglitazone (4 mg kg(-1) per day by an oral administration), repeated oral administration of DBT (2.5 g kg(-1) per day) for 14 days was found to significantly alleviate the hyperglycemia but made no influence on plasma lipid profiles nor weight gain in fructose chow-fed rats. Also, the higher degree of insulin resistance as measured by homeostasis model assessment of basal insulin resistance in fructose chow-fed rats was significantly decreased by repeated DBT treatment. DBT displays the characteristic of rosiglitazone by increasing the whole-body insulin sensitivity in fructose chow-fed rats after 2-week treatment, as evidenced by the marked elevation of composite whole-body insulin sensitivity index during the oral glucose tolerance test. DBT improves insulin sensitivity through increased post-receptor insulin signaling mediated by enhancements in insulin receptor substrate-1-associated phosphatidylinositol 3-kinase step and glucose transporter subtype 4 translocation in soleus muscles of animals exhibiting insulin resistance. DBT is therefore proposed as potentially useful adjuvant therapy for patients with insulin resistance and/or the patients who wish to increase insulin sensitivity.
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Affiliation(s)
- I-Min Liu
- Department of Pharmacy, Tajen University, Yanpu Shiang, Ping Tung Shien, Taiwan
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Kim ED, Kim E, Lee JH, Hyun CK. Gly-Ala-Gly-Val-Gly-Tyr, a novel synthetic peptide, improves glucose transport and exerts beneficial lipid metabolic effects in 3T3-L1 adipoctyes. Eur J Pharmacol 2010; 650:479-85. [PMID: 20951125 DOI: 10.1016/j.ejphar.2010.10.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 10/01/2010] [Accepted: 10/04/2010] [Indexed: 12/31/2022]
Abstract
Recently, it has been demonstrated that fibroin and fibroin-derived peptides enhances insulin sensitivity and glucose metabolism in adipocytes. Here, we show that a synthetic hexapeptide Gly-Ala-Gly-Val-Gly-Tyr (GAGVGY) derived from repetitive amino acid sequence of fibroin improves glucose transport and exerts beneficial lipid metabolic effects in 3T3-L1 adipocytes. GAGVGY increases both basal and insulin-stimulated glucose uptake through enhancement of GLUT1 expression and PI 3-K-dependent GLUT4 translocation, respectively. GAGVGY treatment also led to a significant reduction in the expression of lipogenic genes including sterol regulatory element binding protein-1c (SREBP1c), peroxisome proliferator-activated receptor-γ (PPARγ), and fatty acid synthase (FAS) in mature 3T3-L1 adipocytes, which was corroborated with decreased lipid accumulation by GAGVGY treatment. Additionally, in cells undergoing differentiation, mRNA levels of adipogenic genes including PPARγ and CCAAT/enhancer binding protein α (C/EBPα), stearoyl-CoA desaturase 1 (SCD1), and FAS were suppressed by GAGVGY. Furthermore, GAGVGY increased AMP-activated protein kinase (AMPK) phosphorylation and adiponectin secretion in 3T3-L1 adipocytes. The latter effect was supported with evidence showing increased AMPK activation in C2C12 myocytes treated with 3T3-L1-adipocyte-conditioned medium. Together, our data suggest that GAGVGY has multiple beneficial effects on glucose and lipid metabolism, and would control hyperglycemia without the adverse effect of weight gain.
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Affiliation(s)
- Eun-Do Kim
- School of Life Science, Handong Global University, Pohang, Kyungbuk 791-708, Republic of Korea
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Benton CR, Holloway GP, Han XX, Yoshida Y, Snook LA, Lally J, Glatz JFC, Luiken JJFP, Chabowski A, Bonen A. Increased levels of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1alpha) improve lipid utilisation, insulin signalling and glucose transport in skeletal muscle of lean and insulin-resistant obese Zucker rats. Diabetologia 2010; 53:2008-19. [PMID: 20490453 DOI: 10.1007/s00125-010-1773-1] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 03/26/2010] [Indexed: 01/12/2023]
Abstract
AIMS/HYPOTHESIS Reductions in peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1alpha) levels have been associated with the skeletal muscle insulin resistance. However, in vivo, the therapeutic potential of PGC-1alpha has met with failure, as supra-physiological overexpression of PGC-1alpha induced insulin resistance, due to fatty acid translocase (FAT)-mediated lipid accumulation. Based on physiological and metabolic considerations, we hypothesised that a modest increase in PGC-1alpha levels would limit FAT upregulation and improve lipid metabolism and insulin sensitivity, although these effects may differ in lean and insulin-resistant muscle. METHODS Pgc-1alpha was transfected into lean and obese Zucker rat muscles. Two weeks later we examined mitochondrial biogenesis, intramuscular lipids (triacylglycerol, diacylglycerol, ceramide), GLUT4 and FAT levels, insulin-stimulated glucose transport and signalling protein phosphorylation (thymoma viral proto-oncogene 2 [Akt2], Akt substrate of 160 kDa [AS160]), and fatty acid oxidation in subsarcolemmal and intermyofibrillar mitochondria. RESULTS Electrotransfection yielded physiologically relevant increases in Pgc-1alpha (also known as Ppargc1a) mRNA and protein ( approximately 25%) in lean and obese muscle. This induced mitochondrial biogenesis, and increased FAT and GLUT4 levels, insulin-stimulated glucose transport, and Akt2 and AS160 phosphorylation in lean and obese animals, while bioactive intramuscular lipids were only reduced in obese muscle. Concurrently, PGC-1alpha increased palmitate oxidation in subsarcolemmal, but not in intermyofibrillar mitochondria, in both groups. In obese compared with lean animals, the PGC-1alpha-induced improvement in insulin-stimulated glucose transport was smaller, but intramuscular lipid reduction was greater. CONCLUSIONS/INTERPRETATIONS Increases in PGC-1alpha levels, similar to those that can be induced by physiological stimuli, altered intramuscular lipids and improved fatty acid oxidation, insulin signalling and insulin-stimulated glucose transport, albeit to different extents in lean and insulin-resistant muscle. These positive effects are probably attributable to limiting the PGC-1alpha-induced increase in FAT, thereby preventing bioactive lipid accumulation as has occurred in transgenic PGC-1alpha animals.
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Affiliation(s)
- C R Benton
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, ON, Canada
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Abstract
Comprehensive studies support the notion that the peroxisome proliferator-activated receptors, (PPARs), PPARα, PPARβ/δ, and PPARγ, regulate cell growth, morphogenesis, differentiation, and homeostasis. Agonists of each PPAR subtype exert their effects similarly or distinctly in different tissues such as liver, muscle, fat, and vessels. It is noteworthy that PPARα or PPARγ agonists have pharmacological effects by modulating the activity of AMPK, which is a key cellular energy sensor. However, the role of AMPK in the metabolic effects of PPAR agonists has not been thoroughly focused. Moreover, AMPK activation by PPAR agonists seems to be independent of the receptor activation. This intriguing action of PPAR agonists may account in part for the mechanistic basis of the therapeutics in the treatment of metabolic disease. In this paper, the effects of PPAR agonists on metabolic functions were summarized with particular reference to their AMPK activity regulation.
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Brandt N, De Bock K, Richter EA, Hespel P. Cafeteria diet-induced insulin resistance is not associated with decreased insulin signaling or AMPK activity and is alleviated by physical training in rats. Am J Physiol Endocrinol Metab 2010; 299:E215-24. [PMID: 20484011 DOI: 10.1152/ajpendo.00098.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Excess energy intake via a palatable low-fat diet (cafeteria diet) is known to induce obesity and glucose intolerance in rats. However, the molecular mechanisms behind this adaptation are not known, and it is also not known whether exercise training can reverse it. Male Wistar rats were assigned to 12-wk intervention groups: chow-fed controls (CON), cafeteria diet (CAF), and cafeteria diet plus swimming exercise during the last 4 wk (CAF(TR)). CAF feeding led to increased body weight (16%, P < 0.01) and increased plasma glucose (P < 0.05) and insulin levels (P < 0.01) during an IVGTT, which was counteracted by training. In the perfused hindlimb, insulin-stimulated glucose transport in red gastrocnemius muscle was completely abolished in CAF and rescued by exercise training. Apart from a tendency toward an approximately 20% reduction in both basal and insulin-stimulated Akt Ser(473) phosphorylation (P = 0.051) in the CAF group, there were no differences in insulin signaling (IR Tyr(1150/1151), PI 3-kinase activity, Akt Thr(308), TBC1D4 Thr(642), GSK3-alpha/beta Ser(21/9)) or changes in AMPKalpha1 or -alpha2, GLUT4, Munc18c, or syntaxin 4 protein expression or in phosphorylation of AMPK Thr(172) among the groups. In conclusion, surplus energy intake of a palatable but low-fat cafeteria diet resulted in obesity and insulin resistance that was rescued by exercise training. Interestingly, insulin resistance was not accompanied by major defects in the insulin-signaling cascade or in altered AMPK expression or phosphorylation. Thus, compared with previous studies of high-fat feeding, where insulin signaling is significantly impaired, the mechanism by which CAF diet induces insulin resistance seems different.
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Affiliation(s)
- Nina Brandt
- Molecular Physiology Group, Department of Exercise and Sport Sciences, Copenhagen Muscle Research Centre, University of Copenhagen, 13 Universitetsparken, Copenhagen, Denmark
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Bourron O, Daval M, Hainault I, Hajduch E, Servant JM, Gautier JF, Ferré P, Foufelle F. Biguanides and thiazolidinediones inhibit stimulated lipolysis in human adipocytes through activation of AMP-activated protein kinase. Diabetologia 2010; 53:768-78. [PMID: 20043143 DOI: 10.1007/s00125-009-1639-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 11/26/2009] [Indexed: 01/22/2023]
Abstract
AIMS/HYPOTHESIS In rodent adipocytes, activated AMP-activated protein kinase reduces the lipolytic rate. As the hypoglycaemic drugs metformin and thiazolidinediones activate this enzyme in rodents, we tested the hypothesis that in addition to their known actions they could have an anti-lipolytic effect in human adipocytes. METHODS Adipose tissue was obtained from individuals undergoing plastic surgery. Adipocytes were isolated and incubated with lipolytic agents (isoprenaline, atrial natriuretic peptide) and biguanides or thiazolidinediones. Lipolysis was quantified by the glycerol released in the medium. AMP-activated protein kinase activity and phosphorylation state were determined using standard procedures. RESULTS In human adipocytes, isoprenaline and atrial natriuretic peptide stimulated the lipolytic rate three- to fourfold. Biguanides and thiazolidinediones activated AMP-activated protein kinase and inhibited lipolysis by 30-40%, at least in part by inhibiting hormone-sensitive lipase translocation to the lipid droplet. Inhibition of AMP-activated protein kinase by compound C precluded this inhibitory effect on lipolysis. Stimulation of lipolysis also induced an activation of AMP-activated protein kinase concomitant with a drop in ATP concentration. CONCLUSIONS/INTERPRETATION We show for the first time in human adipocytes that biguanides and thiazolidinediones activate AMP-activated protein kinase, thus counteracting lipolysis induced by lipolytic agents. In addition, beta-agonist- or ANP-stimulated lipolysis increases AMP-activated protein kinase activity. This is because of an increase in the AMP/ATP ratio, linked to activation of some of the released fatty acids into acyl-CoA. AMP-activated protein kinase activation could represent a physiological means of avoiding a deleterious drain of energy during lipolysis but could be used to restrain pharmacological release of fatty acids.
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Affiliation(s)
- O Bourron
- Centre de Recherche des Cordeliers, INSERM, UMR-S 872, 15 rue de l'école de médecine, Paris F-75006, France
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Merlin J, Evans BA, Csikasz RI, Bengtsson T, Summers RJ, Hutchinson DS. The M3-muscarinic acetylcholine receptor stimulates glucose uptake in L6 skeletal muscle cells by a CaMKK-AMPK-dependent mechanism. Cell Signal 2010; 22:1104-13. [PMID: 20206685 DOI: 10.1016/j.cellsig.2010.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Revised: 02/23/2010] [Accepted: 03/01/2010] [Indexed: 11/15/2022]
Abstract
The role of muscarinic acetylcholine receptors (mAChRs) in regulating glucose uptake in L6 skeletal muscle cells was investigated. [(3)H]-2-Deoxyglucose uptake was increased in differentiated L6 cells by insulin, acetylcholine, oxotremorine-M and carbachol. mAChR-mediated glucose uptake was inhibited by the AMPK inhibitor Compound C. Whole cell radioligand binding using [(3)H]-N-methyl scopolamine chloride identified mAChRs in differentiated but not undifferentiated L6 cells and M(3) mAChR mRNA was detected only in differentiated cells. M(3) mAChRs are Gq-coupled, and cholinergic stimulation by the mAChR agonists acetylcholine, oxotremorine-M and carbachol increased Ca(2+) in differentiated but not undifferentiated L6 cells. This was due to muscarinic but not nicotinic activation as responses were antagonised by the muscarinic antagonist atropine but not the nicotinic antagonist tubocurarine. Western blotting showed that both carbachol and the AMPK activator AICAR increased phosphorylation of the AMPKalpha subunit at Thr172, with responses to carbachol blocked by Compound C and the CaMKK inhibitor STO609 but not by the PI3K inhibitor wortmannin. AICAR-stimulated AMPK phosphorylation was not sensitive to STO-609, confirming that this compound inhibits CaMKK but not the classical AMPK kinase LKB1. The TAK1 inhibitor (5Z)-7-oxozeaenol and the G(i) inhibitor pertussis toxin both failed to block AMPK phosphorylation in response to carbachol. Using CHO-K1 cells stably expressing each of the mAChR subtypes (M(1)-M(4)), it was determined that only the M(1) and M(3) mAChRs phosphorylate AMPK, confirming a G(q)-dependent mechanism. This study demonstrates that activation of M(3) mAChRs in L6 skeletal muscle cells stimulates glucose uptake via a CaMKK-AMPK-dependent mechanism, independent of the insulin-stimulated pathway.
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Affiliation(s)
- Jon Merlin
- Department of Pharmacology, Monash Institute of Pharmaceutical Sciences, Monash University, Victoria, 3800, Australia
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Detection of AMP-activated protein kinase in human sera by immuno-isoelectric focusing. J Immunol Methods 2009; 351:24-9. [DOI: 10.1016/j.jim.2009.10.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 09/02/2009] [Accepted: 10/01/2009] [Indexed: 12/24/2022]
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Rosiglitazone prevents high glucose-induced vascular endothelial growth factor and collagen IV expression in cultured mesangial cells. EXPERIMENTAL DIABETES RESEARCH 2009; 2009:910783. [PMID: 19609456 PMCID: PMC2709725 DOI: 10.1155/2009/910783] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Revised: 12/13/2008] [Accepted: 03/27/2009] [Indexed: 11/18/2022]
Abstract
Peroxisome proliferator-activated receptor (PPARγ), a ligand-dependent transcription factor, negatively modulates high glucose effects. We postulated that rosiglitazone (RSG), an activator of PPARγ prevents the upregulation of vascular endothelial growth factor (VEGF) and collagen IV by mesangial cells exposed to high glucose. Primary cultured rat mesangial cells were growth-arrested in 5.6 mM (NG) or 25 mM D-glucose (HG) for up to 48 hours. In HG, PPARγ mRNA and protein were reduced within 3 h, and enhanced ROS generation, expression of p22phox, VEGF and collagen IV, and PKC-ζ membrane association were prevented by RSG. In NG, inhibition of PPARγ caused ROS generation and VEGF expression that were unchanged by RSG. Reduced AMP-activated protein kinase (AMPK) phosphorylation in HG was unchanged with RSG, and VEGF expression was unaffected by AMPK inhibition. Hence, PPARγ is a negative modulator of HG-induced signaling that acts through PKC-ζ but not AMPK and regulates VEGF and collagen IV expression by mesangial cells.
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Kanzleiter T, Wilks D, Preston E, Ye J, Frangioudakis G, Cooney GJ. Regulation of the nuclear hormone receptor nur77 in muscle: influence of exercise-activated pathways in vitro and obesity in vivo. Biochim Biophys Acta Mol Basis Dis 2009; 1792:777-82. [PMID: 19447175 DOI: 10.1016/j.bbadis.2009.05.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/20/2009] [Accepted: 05/11/2009] [Indexed: 11/20/2022]
Abstract
Regular physical exercise is well known to improve glucose and lipid metabolism in skeletal muscle. However, the transcription factors regulating these adaptive changes are not well-characterised. Recently the nuclear orphan receptor nur77 was shown to be induced by exercise and linked to regulation of metabolic gene expression in skeletal muscle. In this study we investigated the regulation of nur77 in muscle by different exercise-activated pathways. Nur77 expression was found to be responsive to adrenergic stimulation and calcium influx, but not to activation of the AMP dependent kinase. These results identify the adrenergic-cyclic AMP-PKA pathway to be the most potent activator of nur77 expression in muscle and therefore the likely cause of increased expression after exercise. We also identified nur77 expression to be reduced in the muscle of obese/insulin resistant rats after high fat feeding. Furthermore exposure to fatty acids, insulin or inflammation was not the cause of decreased nur77 expression in insulin resistant muscle. This suggests a reduced responsiveness to adrenergic stimulation as the likely cause of diminished nur77 expression in muscle of high fat fed rats, which has been observed in obese/insulin resistant individuals. Our results suggest adrenergic stimulation as the most important stimulus for nur77 expression and point to a significant role for this transcription factor in adaptive changes in muscle after exercise and in insulin resistant states.
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Affiliation(s)
- Timo Kanzleiter
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, Sydney, Australia.
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41
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AMPK: an emerging drug target for diabetes and the metabolic syndrome. Cell Metab 2009; 9:407-16. [PMID: 19416711 DOI: 10.1016/j.cmet.2009.03.012] [Citation(s) in RCA: 821] [Impact Index Per Article: 54.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2009] [Revised: 03/15/2009] [Accepted: 03/31/2009] [Indexed: 12/25/2022]
Abstract
Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) is a key player in regulating energy metabolism, placing it at the center stage in studies of diabetes and related metabolic diseases. Expressed in key metabolically relevant organs, AMPK is activated in response to a variety of stimuli, including cellular stress, exercise, and a wide range of hormones and agents that exert impacts on cellular metabolism. Genetic and pharmacological studies demonstrate that AMPK is required for maintaining glucose homeostasis. Activation of AMPK by pharmacological agents presents a unique challenge, given the complexity of the biology, but holds a considerable potential to reverse the metabolic abnormalities associated with type 2 diabetes.
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Coletta DK, Sriwijitkamol A, Wajcberg E, Tantiwong P, Li M, Prentki M, Madiraju M, Jenkinson CP, Cersosimo E, Musi N, Defronzo RA. Pioglitazone stimulates AMP-activated protein kinase signalling and increases the expression of genes involved in adiponectin signalling, mitochondrial function and fat oxidation in human skeletal muscle in vivo: a randomised trial. Diabetologia 2009; 52:723-32. [PMID: 19169664 PMCID: PMC4894502 DOI: 10.1007/s00125-008-1256-9] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Accepted: 12/05/2008] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS The molecular mechanisms by which thiazolidinediones improve insulin sensitivity in type 2 diabetes are not fully understood. We hypothesised that pioglitazone would activate the adenosine 5'-monophosphate-activated protein kinase (AMPK) pathway and increase the expression of genes involved in adiponectin signalling, NEFA oxidation and mitochondrial function in human skeletal muscle. METHODS A randomised, double-blind, parallel study was performed in 26 drug-naive type 2 diabetes patients treated with: (1) pioglitazone (n = 14) or (2) aggressive nutritional therapy (n = 12) to reduce HbA(1c) to levels observed in the pioglitazone-treated group. Participants were assigned randomly to treatment using a table of random numbers. Before and after 6 months, patients reported to the Clinical Research Center of the Texas Diabetes Institute for a vastus lateralis muscle biopsy followed by a 180 min euglycaemic-hyperinsulinaemic (80 mU m(-2) min(-1)) clamp. RESULTS All patients in the pioglitazone (n = 14) or nutritional therapy (n = 12) group were included in the analysis. Pioglitazone significantly increased plasma adiponectin concentration by 79% and reduced fasting plasma NEFA by 35% (both p < 0.01). Following pioglitazone, insulin-stimulated glucose disposal increased by 30% (p < 0.01), and muscle AMPK and acetyl-CoA carboxylase (ACC) phosphorylation increased by 38% and 53%, respectively (p < 0.05). Pioglitazone increased mRNA levels for adiponectin receptor 1 and 2 genes (ADIPOR1, ADIPOR2), peroxisome proliferator-activated receptor gamma, coactivator 1 gene (PPARGC1) and multiple genes involved in mitochondrial function and fat oxidation. Despite a similar reduction in HbA(1c) and similar improvement in insulin sensitivity with nutritional therapy, there were no significant changes in muscle AMPK and ACC phosphorylation, or the expression of ADIPOR1, ADIPOR2, PPARGC1 and genes involved in mitochondrial function and fat oxidation. No adverse (or unexpected) effects or side effects were reported from the study. CONCLUSIONS/INTERPRETATIONS Pioglitazone increases plasma adiponectin levels, stimulates muscle AMPK signalling and increases the expression of genes involved in adiponectin signalling, mitochondrial function and fat oxidation. These changes may represent an important cellular mechanism by which thiazolidinediones improve skeletal muscle insulin sensitivity. TRIAL REGISTRATION NCT 00816218 FUNDING: This trial was funded by National Institutes of Health Grant DK24092, VA Merit Award, GCRC Grant RR01346, Executive Research Committee Research Award from the University of Texas Health Science Center at San Antonio, American Diabetes Association Junior Faculty Award, American Heart Association National Scientist Development Grant, Takeda Pharmaceuticals North America Grant and Canadian Institute of Health Research Grant.
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Affiliation(s)
- D K Coletta
- Center for Metabolic Biology, College of Liberal Arts and Sciences, Arizona State University, P.O. Box 873704, Tempe, AZ 85287-3704, USA.
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Norris AW, Hirshman MF, Yao J, Jessen N, Musi N, Chen L, Sivitz WI, Goodyear LJ, Kahn CR. Endogenous peroxisome proliferator-activated receptor-gamma augments fatty acid uptake in oxidative muscle. Endocrinology 2008; 149:5374-83. [PMID: 18653710 PMCID: PMC2584586 DOI: 10.1210/en.2008-0100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In the setting of insulin resistance, agonists of peroxisome proliferator-activated receptor (PPAR)-gamma restore insulin action in muscle and promote lipid redistribution. Mice with muscle-specific knockout of PPARgamma (MuPPARgammaKO) develop excess adiposity, despite reduced food intake and normal glucose disposal in muscle. To understand the relation between muscle PPARgamma and lipid accumulation, we studied the fuel energetics of MuPPARgammaKO mice. Compared with controls, MuPPARgammaKO mice exhibited significantly increased ambulatory activity, muscle mitochondrial uncoupling, and respiratory quotient. Fitting with this latter finding, MuPPARgammaKO animals compared with control siblings exhibited a 25% reduction in the uptake of the fatty acid tracer 2-bromo-palmitate (P < 0.05) and a 13% increase in serum nonesterified fatty acids (P = 0.05). These abnormalities were associated with no change in AMP kinase (AMPK) phosphorylation, AMPK activity, or phosphorylation of acetyl-CoA carboxylase in muscle and occurred despite increased expression of fatty acid transport protein 1. Palmitate oxidation was not significantly altered in MuPPARgammaKO mice despite the increased expression of several genes promoting lipid oxidation. These data demonstrate that PPARgamma, even in the absence of exogenous activators, is required for normal rates of fatty acid uptake in oxidative skeletal muscle via mechanisms independent of AMPK and fatty acid transport protein 1. Thus, when PPARgamma activity in muscle is absent or reduced, there will be decreased fatty acid disposal leading to diminished energy utilization and ultimately adiposity.
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Affiliation(s)
- Andrew W Norris
- Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA.
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Fujii N, Ho RC, Manabe Y, Jessen N, Toyoda T, Holland WL, Summers SA, Hirshman MF, Goodyear LJ. Ablation of AMP-activated protein kinase alpha2 activity exacerbates insulin resistance induced by high-fat feeding of mice. Diabetes 2008; 57:2958-66. [PMID: 18728234 PMCID: PMC2570392 DOI: 10.2337/db07-1187] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
OBJECTIVE We determined whether muscle AMP-activated protein kinase (AMPK) has a role in the development of insulin resistance. RESEARCH DESIGN AND METHODS Muscle-specific transgenic mice expressing an inactive form of the AMPK alpha2 catalytic subunit (alpha2i TG) and their wild-type littermates were fed either a high-fat (60% kcal fat) or a control (10% kcal fat) diet for 30 weeks. RESULTS Compared with wild-type mice, glucose tolerance in alpha2i TG mice was slightly impaired on the control diet and significantly impaired on the high-fat diet. To determine whether the whole-body glucose intolerance was associated with impaired insulin sensitivity in skeletal muscle, glucose transport in response to submaximal insulin (450 microU/ml) was measured in isolated soleus muscles. On the control diet, insulin-stimulated glucose transport was reduced by approximately 50% in alpha2i TG mice compared with wild-type mice. High-fat feeding partially decreased insulin-stimulated glucose transport in wild-type mice, while high-fat feeding resulted in a full blunting of insulin-stimulated glucose transport in the alpha2i TG mice. High-fat feeding in alpha2i TG mice was accompanied by decreased expression of insulin signaling proteins in gastrocnemius muscle. CONCLUSIONS The lack of skeletal muscle AMPK alpha2 activity exacerbates the development of glucose intolerance and insulin resistance caused by high-fat feeding and supports the thesis that AMPK alpha2 is an important target for the prevention/amelioration of skeletal muscle insulin resistance through lifestyle (exercise) and pharmacologic (e.g., metformin) treatments.
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Affiliation(s)
- Nobuharu Fujii
- Department of Medicine, Research Division, Joslin Diabetes Center, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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45
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Louden E, Chi MM, Moley KH. Crosstalk between the AMP-activated kinase and insulin signaling pathways rescues murine blastocyst cells from insulin resistance. Reproduction 2008; 136:335-44. [PMID: 18577554 DOI: 10.1530/rep-08-0161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Maternal insulin resistance results in poor pregnancy outcomes. In vivo and in vitro exposure of the murine blastocyst to high insulin or IGF1 results in the down-regulation of the IGF1 receptor (IGF1R). This in turn leads to decreased glucose uptake, increased apoptosis, as well as pregnancy resorption and growth restriction. Recent studies have shown that blastocyst activation of AMP-activated protein kinase (AMPK) reverses these detrimental effects; however, the mechanism was not clear. The objective of this study was to determine how AMPK activation rescues the insulin-resistant blastocyst. Using trophoblast stem (TS) cells derived from the blastocyst, insulin resistance was recreated by transfecting with siRNA to Igf1r and down-regulating expression of the protein. These cells were then exposed to AMPK activators 5-aminoimidazole-4-carboxamide riboside and phenformin, and evaluated for apoptosis, insulin-stimulated 2-deoxyglucose uptake, PI3-kinase activity, and levels of phospho-AKT, phospho-mTor, and phospho-70S6K. Surprisingly, disrupted insulin signaling led to decreased AMPK activity in TS cells. Activators reversed these effects by increasing the AMP/ATP ratio. Moreover, this treatment increased insulin-stimulated 2-deoxyglucose transport and cell survival, and led to an increase in PI3-kinase activity, as well as increased P-mTOR and p70S6K levels. This study is the first to demonstrate significant crosstalk between the AMPK and insulin signaling pathways in embryonic cells, specifically the enhanced response of PI3K/AKT/mTOR to AMPK activation. Decreased insulin signaling also resulted in decreased AMPK activation. These findings provide mechanistic targets in the AMPK signaling pathway that may be essential for improved pregnancy success in insulin-resistant states.
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Affiliation(s)
- Erica Louden
- Department of OB/GYN, Washington University School of Medicine, 7th Floor McDonnell Science, 660 S. Euclid Avenue, Campus Box 8064, St Louis, Missouri 63110, USA
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Zhu MJ, Han B, Tong J, Ma C, Kimzey JM, Underwood KR, Xiao Y, Hess BW, Ford SP, Nathanielsz PW, Du M. AMP-activated protein kinase signalling pathways are down regulated and skeletal muscle development impaired in fetuses of obese, over-nourished sheep. J Physiol 2008; 586:2651-64. [PMID: 18372306 DOI: 10.1113/jphysiol.2007.149633] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Maternal obesity and over-nutrition give rise to both obstetric problems and neonatal morbidity. The objective of this study was to evaluate effects of maternal obesity and over-nutrition on signalling of the AMP-activated protein kinase (AMPK) pathway in fetal skeletal muscle in an obese pregnant sheep model. Non-pregnant ewes were assigned to a control group (Con, fed 100% of NRC nutrient recommendations, n = 7) or obesogenic group (OB, fed 150% of National Research Council (NRC) recommendations, n = 7) diet from 60 days before to 75 days after conception (term 150 days) when fetal semitendinosus skeletal muscle (St) was sampled. OB mothers developed severe obesity accompanied by higher maternal and fetal plasma glucose and insulin levels. In fetal St, activity of phosphoinositide-3 kinase (PI3K) associated with insulin receptor substrate-1 (IRS-1) was attenuated (P < 0.05), in agreement with the increased phophorylation of IRS-1 at serine 1011. Phosphorylation of AMP-activated protein kinase (AMPK) at Thr 172, acetyl-CoA carboxylase at Ser 79, tuberous sclerosis 2 at Thr 1462 and eukaryotic translation initiation factor 4E-binding protein 1 at Thr 37/46 were reduced in OB compared to Con fetal St. No difference in energy status (AMP/ATP ratio) was observed. The expression of protein phosphatase 2C was increased in OB compared to Con fetal St. Plasma tumour necrosis factor alpha (TNFalpha) was increased in OB fetuses indicating an increased inflammatory state. Expression of peroxisome proliferator-activated receptor gamma (PPARgamma) was higher in OB St, indicating enhanced adipogenesis. The glutathione: glutathione disulphide ratio was also lower, showing increased oxidative stress in OB fetal St. In summary, we have demonstrated decreased signalling of the AMPK system in skeletal muscle of fetuses of OB mothers, which may play a role in altered muscle development and development of insulin resistance in the offspring.
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Affiliation(s)
- Mei J Zhu
- Department of Animal Science and Interdepartmental Molecular and Cellular Life Sciences Program, University of Wyoming, Laramie, WY 82071, USA
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Benton CR, Holloway GP, Campbell SE, Yoshida Y, Tandon NN, Glatz JFC, Luiken JJJFP, Spriet LL, Bonen A. Rosiglitazone increases fatty acid oxidation and fatty acid translocase (FAT/CD36) but not carnitine palmitoyltransferase I in rat muscle mitochondria. J Physiol 2008; 586:1755-66. [PMID: 18238811 DOI: 10.1113/jphysiol.2007.146563] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) alter the expression of genes involved in regulating lipid metabolism. Rosiglitazone, a PPARgamma agonist, induces tissue-specific effects on lipid metabolism; however, its mode of action in skeletal muscle remains unclear. Since fatty acid translocase (FAT/CD36) was recently identified as a possible regulator of skeletal muscle fatty acid transport and mitochondrial fatty acid oxidation, we examined in this tissue the effects of rosiglitazone infusion (7 days, 1 mg day(-1)) on FAT/CD36 mRNA and protein, its plasmalemmal content and fatty acid transport. In addition, in isolated subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondria we examined rates of fatty acid oxidation, FAT/CD36 and carnitine palmitoyltransferase I (CPTI) protein, and CPTI and beta-hydroxyacyl CoA dehydrogenase (beta-HAD) activities. Rosiglitazone did not alter FAT/CD36 mRNA or protein expression, FAT/CD36 plasmalemmal content, or the rate of fatty acid transport into muscle (P > 0.05). In contrast, rosiglitazone increased the rates of fatty acid oxidation in both SS (+21%) and IMF mitochondria (+36%). This was accompanied by concomitant increases in FAT/CD36 in subsarcolemmal (SS) (+43%) and intermyofibrillar (IMF) mitochondria (+46%), while SS and IMF CPTI protein content, and CPTI submaximal and maximal activities (P > 0.05) were not altered. Similarly, citrate synthase (CS) and beta-HAD activities were also not altered by rosiglitazone in SS and IMF mitochondria (P > 0.05). These studies provide another example whereby changes in mitochondrial fatty oxidation are associated with concomitant changes in mitochondrial FAT/CD36 independent of any changes in CPTI. Moreover, these studies identify for the first time a mechanism by which rosiglitazone stimulates fatty acid oxidation in skeletal muscle, namely the chronic, subcellular relocation of FAT/CD36 to mitochondria.
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Affiliation(s)
- Carley R Benton
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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48
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Liu IM, Tzeng TF, Liou SS, Lan TW. Myricetin, a naturally occurring flavonol, ameliorates insulin resistance induced by a high-fructose diet in rats. Life Sci 2007; 81:1479-88. [PMID: 17976658 DOI: 10.1016/j.lfs.2007.08.045] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 08/19/2007] [Accepted: 08/19/2007] [Indexed: 11/26/2022]
Abstract
The present study was conducted to explore the effects of myricetin on insulin resistance in rats fed for 6 weeks with a diet containing 60% fructose. Repeated intravenous (i.v.) injection of myricetin (1 mg/kg per injection, 3 times daily) for 14 days was found to significantly decrease the high glucose and triglyceride levels in plasma of fructose chow-fed rats. Also, the higher degree of insulin resistance in fructose chow-fed rats as measured by homeostasis model assessment of basal insulin resistance was significantly decreased by myricetin treatment. Myricetin increased the whole-body insulin sensitivity in fructose chow-fed rats, as evidenced by the marked elevation of composite whole-body insulin sensitivity index during the oral glucose tolerance test. Myricetin was found to reverse the defect in expression of insulin receptor substrate-1 (IRS-1) and the p85 regulatory subunit of phosphatidylinositol 3-kinase (PI 3-kinase) in soleus muscle of fructose chow-fed rats under the basal state, despite the protein expression of insulin receptor (IR). Increased basal phosphorylation of IR and IRS-1 as well as Akt was observed in parallel. The reduced level of insulin action on phosphorylation of IR, IRS-1 and Akt in soleus muscle of fructose chow-fed rats was reversed by myricetin treatment. Furthermore, myricetin treatment improved the defective insulin action on the translocation of glucose transporter subtype 4 (GLUT 4) in insulin-resistant soleus muscle. These findings indicate that myricetin improves insulin sensitivity through the enhancement of insulin action on IRS-1-associated PI 3-kinase and GLUT 4 activity in soleus muscles of animals exhibiting insulin resistance.
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Affiliation(s)
- I-Min Liu
- Department of Pharmacy, Tajen University, Yen-Pou, Ping Tung Shien, Taiwan, ROC.
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49
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Ho RC, Fujii N, Witters LA, Hirshman MF, Goodyear LJ. Dissociation of AMP-activated protein kinase and p38 mitogen-activated protein kinase signaling in skeletal muscle. Biochem Biophys Res Commun 2007; 362:354-9. [PMID: 17709097 PMCID: PMC2040310 DOI: 10.1016/j.bbrc.2007.07.154] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Accepted: 07/30/2007] [Indexed: 12/27/2022]
Abstract
AMP-activated protein kinase (AMPK) is widely recognized as an important regulator of glucose transport in skeletal muscle. The p38 mitogen-activated protein kinase (MAPK) has been proposed to be a component of AMPK-mediated signaling. Here we used several different models of altered AMPK activity to determine whether p38 MAPK is a downstream intermediate of AMPK-mediated signaling in skeletal muscle. First, L6 myoblasts and myotubes were treated with AICAR, an AMPK stimulator. AMPK phosphorylation was significantly increased, but there was no change in p38 MAPK phosphorylation. Similarly, AICAR incubation of isolated rat extensor digitorum longus (EDL) muscles did not increase p38 phosphorylation. Next, we used transgenic mice expressing an inactive form of the AMPKalpha2 catalytic subunit in skeletal muscle (AMPKalpha2i TG mice). AMPKalpha2i TG mice did not exhibit any defect in basal or contraction-induced p38 MAPK phosphorylation. We also used transgenic mice expressing an activating mutation in the AMPKgamma1 subunit (gamma1R70Q TG mice). Despite activated AMPK, basal p38 MAPK phosphorylation was not different between wild type and gamma1R70Q TG mice. In addition, muscle contraction-induced p38 MAPK phosphorylation was significantly blunted in the gamma1R70Q TG mice. In conclusion, increasing AMPK activity by AICAR and AMPKgamma1 mutation does not increase p38 MAPK phosphorylation in skeletal muscle. Furthermore, AMPKalpha2i TG mice lacking contraction-stimulated AMPK activity have normal p38 MAPK phosphorylation. These results suggest that p38 MAPK is not a downstream component of AMPK-mediated signaling in skeletal muscle.
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Affiliation(s)
- Richard C Ho
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA
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50
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Fraser SA, Gimenez I, Cook N, Jennings I, Katerelos M, Katsis F, Levidiotis V, Kemp BE, Power DA. Regulation of the renal-specific Na+-K+-2Cl- co-transporter NKCC2 by AMP-activated protein kinase (AMPK). Biochem J 2007; 405:85-93. [PMID: 17341212 PMCID: PMC1925243 DOI: 10.1042/bj20061850] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The renal-specific NKCC2 (Na+-K+-2Cl- co-transporter 2) is regulated by changes in phosphorylation state, however, the phosphorylation sites and kinases responsible have not been fully elucidated. In the present study, we demonstrate that the metabolic sensing kinase AMPK (AMP-activated protein kinase) phosphorylates NKCC2 on Ser126 in vitro. Co-precipitation experiments indicated that there is a physical association between AMPK and the N-terminal cytoplasmic domain of NKCC2. Activation of AMPK in the MMDD1 (mouse macula densa-derived 1) cell line resulted in an increase in Ser126 phosphorylation in situ, suggesting that AMPK may phosphorylate NKCC2 in vivo. The functional significance of Ser126 phosphorylation was examined by mutating the serine residue to an alanine residue resulting in a marked reduction in co-transporter activity when exogenously expressed in Xenopus laevis oocytes under isotonic conditions. Under hypertonic conditions no significant change of activity was observed. Therefore the present study identifies a novel phosphorylation site that maintains NKCC2-mediated transport under isotonic or basal conditions. Moreover, the metabolic-sensing kinase, AMPK, is able to phosphorylate this site, potentially linking the cellular energy state with changes in co-transporter activity.
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Affiliation(s)
- Scott A Fraser
- The Burnet Research Institute, Austin Health, Studley Road, Heidelberg, Victoria 3084, Australia.
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