1
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Qi W, Zhu D, Yin P, Gu X, Zhao Z, Li M, Dong C, Tang Q, Xie W, Zhou T, Xia H, Qiu X, Yang X, Gao G. Pigment Epithelium-Derived Factor, a Novel Adipokine, Contributes to Gestational Diabetes Mellitus. J Clin Endocrinol Metab 2023; 109:e356-e369. [PMID: 37440564 DOI: 10.1210/clinem/dgad413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 07/04/2023] [Accepted: 07/10/2023] [Indexed: 07/15/2023]
Abstract
CONTEXT Excessive insulin resistance, inadequate insulin compensation, or both could result in gestational diabetes mellitus (GDM). Levels of pigment epithelium-derived factor (PEDF), a novel adipokine that could induce insulin resistance, are high in patients with obesity and diabetes. However, the impact of PEDF in pregnancy remains unknown. OBJECTIVE This study aimed to elucidate the role of PEDF on insulin resistance and compensatory elevation of insulin levels during normal pregnancy and in patients with GDM. METHODS In this population-based and cohort study, logistic regression analysis was performed to determine the association of PEDF/adiponectin/leptin levels with the risk of developing GDM and to predict postpartum prediabetes. PEDF protein, PEDF transgenic mice, PEDF knockout mice, and PEDF-neutralized antibodies were used to observe changes in insulin resistance and insulin levels with pregnancy. RESULTS Plasma PEDF levels were increased in normal pregnancy and higher in GDM women. Higher PEDF levels were associated with the increased risk of developing GDM and emerged as a significant independent determinant of postpartum prediabetes in GDM women. Mechanistically, in vivo and in vitro experiments revealed that PEDF induced insulin resistance by inhibiting the insulin signaling pathway. CONCLUSION In addition to insulin resistance and upregulated insulin levels in normal pregnancy and GDM, aberrant PEDF levels can serve as a "fingerprint" of metabolic abnormalities during pregnancy. Thus, PEDF is a valuable biomarker but could interfere with the time course for early diagnosis and prognosis of GDM.
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Affiliation(s)
- Weiwei Qi
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Dan Zhu
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ping Yin
- Department of Clinical Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
| | - Xiaoqiong Gu
- Department of Clinical Biological Resource Bank, Guangzhou Institute of Pediatrics, Guangdong Provincial Key Laboratory of Research in Structural Birth Defect Disease, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Zhen Zhao
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Miaoxin Li
- Center for Precision Medicine, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Chang Dong
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Qilong Tang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Wanting Xie
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Ti Zhou
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Huimin Xia
- Division of Birth Cohort Study, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Xiu Qiu
- Division of Birth Cohort Study, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou 510623, China
| | - Xia Yang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Guangdong Engineering & Technology Research Center for Gene Manipulation and Biomacromolecular Products, Sun Yat-sen University, Guangzhou, China
| | - Guoquan Gao
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
- Guangdong Province Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China
- Key Laboratory of Tropical Disease Control, Sun Yat-sen University, Ministry of Education, Guangzhou, China
- Guangdong Provincial Key Laboratory of Diabetology& Guangzhou Municipal Key Laboratory of Mechanistic and Translational Obesity Research, Medical Center for Comprehensive Weight Control, The Third Affiliated Hospital of Sun Yat-sen University Guangzhou, Guangdong, China
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2
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The insulin receptor endocytosis. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2023; 194:79-107. [PMID: 36631202 DOI: 10.1016/bs.pmbts.2022.06.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Insulin signaling controls multiple aspects of animal physiology. At the cell surface, insulin binds and activates the insulin receptor (IR), a receptor tyrosine kinase. Insulin promotes a large conformational change of IR and stabilizes the active conformation. The insulin-activated IR triggers signaling cascades, thus controlling metabolism, growth, and proliferation. The activated IR undergoes internalization by clathrin- or caveolae-mediated endocytosis. The IR endocytosis plays important roles in insulin clearance from blood, and distribution and termination of the insulin signaling. Despite decades of extensive studies, the mechanism and regulation of IR endocytosis and its contribution to pathophysiology remain incompletely understood. Here we discuss recent findings that provide insights into the molecular mechanisms and regulatory pathways that mediate the IR endocytosis.
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3
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Yadav Y, Dey CS. PP2Cα positively regulates neuronal insulin signalling and aggravates neuronal insulin resistance. FEBS J 2022; 289:7561-7581. [PMID: 35810470 DOI: 10.1111/febs.16574] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 05/11/2022] [Accepted: 07/08/2022] [Indexed: 01/14/2023]
Abstract
PP2Cα is one of the newly identified isoforms of metal-dependent protein phosphatases (PPM). The role of this phosphatase in neuronal insulin signalling is completely unknown. In the present study, we show insulin-mediated rapid upregulation of a protein of the insulin signalling cascade, PP2Cα, in mouse N2a cells and human SH-SY5Y cells. By contrast, such PP2Cα upregulation is not observed in insulin-resistant conditions despite insulin stimulation. Here, we report that, under insulin-sensitive and insulin-resistant conditions, the translation of PP2Cα was regulated by insulin through c-Jun N-terminal kinase. PP2Cα in turn dephosphorylated a novel inhibitory site of insulin receptor substrate-1 at Ser522 and AMP-activated protein kinase, hence positively regulating neuronal insulin signalling and insulin resistance.
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Affiliation(s)
- Yamini Yadav
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, India
| | - Chinmoy Sankar Dey
- Kusuma School of Biological Sciences, Indian Institute of Technology, Delhi, India
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4
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Frendo-Cumbo S, Li T, Ammendolia DA, Coyaud E, Laurent EM, Liu Y, Bilan PJ, Polevoy G, Raught B, Brill JA, Klip A, Brumell JH. DCAF7 regulates cell proliferation through IRS1-FOXO1 signaling. iScience 2022; 25:105188. [PMID: 36248734 PMCID: PMC9556925 DOI: 10.1016/j.isci.2022.105188] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 07/13/2022] [Accepted: 09/20/2022] [Indexed: 12/13/2022] Open
Abstract
Cell proliferation is dependent on growth factors insulin and IGF1. We sought to identify interactors of IRS1, the most proximal mediator of insulin/IGF1 signaling, that regulate cell proliferation. Using proximity-dependent biotin identification (BioID), we detected 40 proteins displaying proximal interactions with IRS1, including DCAF7 and its interacting partners DYRK1A and DYRK1B. In HepG2 cells, DCAF7 knockdown attenuated cell proliferation by inducing cell cycle arrest at G2. DCAF7 expression was required for insulin-stimulated AKT phosphorylation, and its absence promoted nuclear localization of the transcription factor FOXO1. DCAF7 knockdown induced expression of FOXO1-target genes implicated in G2 cell cycle inhibition, correlating with G2 cell cycle arrest. In Drosophila melanogaster, wing-specific knockdown of DCAF7/wap caused smaller wing size and lower wing cell number; the latter recovered upon double knockdown of wap and dfoxo. We propose that DCAF7 regulates cell proliferation and cell cycle via IRS1-FOXO1 signaling, of relevance to whole organism growth.
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Affiliation(s)
- Scott Frendo-Cumbo
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Taoyingnan Li
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Dustin A. Ammendolia
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Etienne Coyaud
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - Estelle M.N. Laurent
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada
| | - Yuan Liu
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Philip J. Bilan
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Gordon Polevoy
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON M5G 2C1, Canada,Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - Julie A. Brill
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada,Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Amira Klip
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Physiology, University of Toronto, Toronto, ON M5G 1L7, Canada,Department of Biochemistry, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - John H. Brumell
- Cell Biology Program, Hospital for Sick Children, Toronto, ON M5G 0A4, Canada,Department of Molecular Genetics, University of Toronto, Toronto, ON M5G 1L7, Canada,Institute of Medical Science, University of Toronto, Toronto, ON M5S 1A8, Canada,SickKids IBD Centre, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada,Corresponding author
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5
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Chazarin B, Benhaim-Delarbre M, Brun C, Anzeraey A, Bertile F, Terrien J. Molecular Liver Fingerprint Reflects the Seasonal Physiology of the Grey Mouse Lemur ( Microcebus murinus) during Winter. Int J Mol Sci 2022; 23:4254. [PMID: 35457071 PMCID: PMC9028843 DOI: 10.3390/ijms23084254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 12/14/2022] Open
Abstract
Grey mouse lemurs (Microcebus murinus) are primates that respond to environmental energetic constraints through strong physiological seasonality. They notably fatten during early winter (EW), and mobilize their lipid reserves while developing glucose intolerance during late winter (LW), when food availability is low. To decipher how the hepatic mechanisms may support such metabolic flexibility, we analyzed the liver proteome of adult captive male mouse lemurs, whose seasonal regulations are comparable to their wild counterparts. We highlight profound hepatic changes that reflect fat accretion in EW at the whole-body level, without triggering an ectopic storage of fat in the liver, however. Moreover, molecular regulations are consistent with the decrease in liver glucose utilization in LW, and therefore with reduced tolerance to glucose. However, no major regulation was seen in insulin signaling/resistance pathways. Fat mobilization in LW appeared possibly linked to the reactivation of the reproductive system while enhanced liver detoxification may reflect an anticipation to return to summer levels of food intake. Overall, these results show that the physiology of mouse lemurs during winter relies on solid molecular foundations in liver processes to adapt fuel partitioning while opposing the development of a pathological state despite large lipid fluxes.
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Affiliation(s)
- Blandine Chazarin
- Laboratoire de Spectrométrie de Masse Bio-Organique, Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS, UMR 7178, 25 Rue Becquerel, 67087 Strasbourg, France; (B.C.); (M.B.-D.); (C.B.)
- Infrastructure Nationale de Protéomique ProFI—FR 2048, 25 Rue Becquerel, 67087 Strasbourg, France
| | - Margaux Benhaim-Delarbre
- Laboratoire de Spectrométrie de Masse Bio-Organique, Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS, UMR 7178, 25 Rue Becquerel, 67087 Strasbourg, France; (B.C.); (M.B.-D.); (C.B.)
- Infrastructure Nationale de Protéomique ProFI—FR 2048, 25 Rue Becquerel, 67087 Strasbourg, France
| | - Charlotte Brun
- Laboratoire de Spectrométrie de Masse Bio-Organique, Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS, UMR 7178, 25 Rue Becquerel, 67087 Strasbourg, France; (B.C.); (M.B.-D.); (C.B.)
- Infrastructure Nationale de Protéomique ProFI—FR 2048, 25 Rue Becquerel, 67087 Strasbourg, France
| | - Aude Anzeraey
- Unité Mécanismes Adaptatifs et Evolution (MECADEV), UMR 7179, CNRS, Muséum National d’Histoire Naturelle, 1 Avenue du Petit Château, 91800 Brunoy, France;
| | - Fabrice Bertile
- Laboratoire de Spectrométrie de Masse Bio-Organique, Institut Pluridisciplinaire Hubert Curien, University of Strasbourg, CNRS, UMR 7178, 25 Rue Becquerel, 67087 Strasbourg, France; (B.C.); (M.B.-D.); (C.B.)
- Infrastructure Nationale de Protéomique ProFI—FR 2048, 25 Rue Becquerel, 67087 Strasbourg, France
| | - Jérémy Terrien
- Unité Mécanismes Adaptatifs et Evolution (MECADEV), UMR 7179, CNRS, Muséum National d’Histoire Naturelle, 1 Avenue du Petit Château, 91800 Brunoy, France;
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6
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Abstract
Tumour necrosis factor (TNF) is a classical, pleiotropic pro-inflammatory cytokine. It is also the first 'adipokine' described to be produced from adipose tissue, regulated in obesity and proposed to contribute to obesity-associated metabolic disease. In this review, we provide an overview of TNF in the context of metabolic inflammation or metaflammation, its discovery as a metabolic messenger, its sites and mechanisms of action and some critical considerations for future research. Although we focus on TNF and the studies that elucidated its immunometabolic actions, we highlight a conceptual framework, generated by these studies, that is equally applicable to the complex network of pro-inflammatory signals, their biological activity and their integration with metabolic regulation, and to the field of immunometabolism more broadly.
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Affiliation(s)
- Jaswinder K Sethi
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK.
- National Institute for Health Research Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton National Health Service (NHS) Foundation Trust, Southampton, UK.
- Institute for Life Sciences, University of Southampton, Southampton, UK.
| | - Gökhan S Hotamisligil
- Sabri Ülker Center for Metabolic Research, Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA, USA.
- Harvard-MIT Broad Institute, Boston, MA, USA.
- Harvard Stem Cell Institute, Boston, MA, USA.
- The Joslin Diabetes Center, Boston, MA, USA.
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7
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Abstract
The molecular mechanisms of cellular insulin action have been the focus of much investigation since the discovery of the hormone 100 years ago. Insulin action is impaired in metabolic syndrome, a condition known as insulin resistance. The actions of the hormone are initiated by binding to its receptor on the surface of target cells. The receptor is an α2β2 heterodimer that binds to insulin with high affinity, resulting in the activation of its tyrosine kinase activity. Once activated, the receptor can phosphorylate a number of intracellular substrates that initiate discrete signaling pathways. The tyrosine phosphorylation of some substrates activates phosphatidylinositol-3-kinase (PI3K), which produces polyphosphoinositides that interact with protein kinases, leading to activation of the kinase Akt. Phosphorylation of Shc leads to activation of the Ras/MAP kinase pathway. Phosphorylation of SH2B2 and of Cbl initiates activation of G proteins such as TC10. Activation of Akt and other protein kinases produces phosphorylation of a variety of substrates, including transcription factors, GTPase-activating proteins, and other kinases that control key metabolic events. Among the cellular processes controlled by insulin are vesicle trafficking, activities of metabolic enzymes, transcriptional factors, and degradation of insulin itself. Together these complex processes are coordinated to ensure glucose homeostasis.
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8
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Burillo J, Marqués P, Jiménez B, González-Blanco C, Benito M, Guillén C. Insulin Resistance and Diabetes Mellitus in Alzheimer's Disease. Cells 2021; 10:1236. [PMID: 34069890 PMCID: PMC8157600 DOI: 10.3390/cells10051236] [Citation(s) in RCA: 78] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Revised: 05/11/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
Type 2 diabetes mellitus is a progressive disease that is characterized by the appearance of insulin resistance. The term insulin resistance is very wide and could affect different proteins involved in insulin signaling, as well as other mechanisms. In this review, we have analyzed the main molecular mechanisms that could be involved in the connection between type 2 diabetes and neurodegeneration, in general, and more specifically with the appearance of Alzheimer's disease. We have studied, in more detail, the different processes involved, such as inflammation, endoplasmic reticulum stress, autophagy, and mitochondrial dysfunction.
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Affiliation(s)
- Jesús Burillo
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Patricia Marqués
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Beatriz Jiménez
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Carlos González-Blanco
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Manuel Benito
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
| | - Carlos Guillén
- Department of Biochemistry, Complutense University, 28040 Madrid, Spain; (J.B.); (P.M.); (B.J.); (C.G.-B.); (M.B.)
- Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 28040 Madrid, Spain
- Mechanisms of Insulin Resistance (MOIR2), General Direction of Universities and Investigation (CCMM), 28040 Madrid, Spain
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9
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Abstract
Aging is characterized by a progressive loss of physiological function leading to increase in the vulnerability to death. This deterioration process occurs in all living organisms and is the primary risk factor for pathological conditions including obesity, type 2 diabetes mellitus, Alzheimer's disease and cardiovascular diseases. Most of the age-related diseases have been associated with impairment of action of an important hormone, namely insulin. It is well-known that this hormone is a critical mediator of metabolism, growth, proliferation and differentiation. Insulin action depends on two processes that determine its circulating levels, insulin secretion and clearance, and insulin sensitivity in its target tissues. Aging has deleterious effects on these three mechanisms, impairing insulin action, thereby increasing the risk for diseases and death. Thus, improving insulin action may be an important strategy to have a healthier and longer life.
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10
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Hoevenaar M, Goossens D, Roorda J. Angiotensin-converting enzyme 2, the complement system, the kallikrein-kinin system, type-2 diabetes, interleukin-6, and their interactions regarding the complex COVID-19 pathophysiological crossroads. J Renin Angiotensin Aldosterone Syst 2020; 21:1470320320979097. [PMID: 33283602 PMCID: PMC7724427 DOI: 10.1177/1470320320979097] [Citation(s) in RCA: 4] [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: 06/24/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022] Open
Abstract
Because of the current COVID-19-pandemic, the world is currently being held hostage in various lockdowns. ACE2 facilitates SARS-CoV-2 cell-entry, and is at the very center of several pathophysiological pathways regarding the RAAS, CS, KKS, T2DM, and IL-6. Their interactions with severe COVID-19 complications (e.g. ARDS and thrombosis), and potential therapeutic targets for pharmacological intervention, will be reviewed.
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Affiliation(s)
| | | | - Janne Roorda
- Medical Doctor, General Practice
van Dijk, Oisterwijk, The Netherlands
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11
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Wong CY, Al-Salami H, Dass CR. C2C12 cell model: its role in understanding of insulin resistance at the molecular level and pharmaceutical development at the preclinical stage. J Pharm Pharmacol 2020; 72:1667-1693. [PMID: 32812252 DOI: 10.1111/jphp.13359] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 07/17/2020] [Accepted: 07/25/2020] [Indexed: 12/11/2022]
Abstract
OBJECTIVES The myoblast cell line, C2C12, has been utilised extensively in vitro as an examination model in understanding metabolic disease progression. Although it is indispensable in both preclinical and pharmaceutical research, a comprehensive review of its use in the investigation of insulin resistance progression and pharmaceutical development is not available. KEY FINDINGS C2C12 is a well-documented model, which can facilitate our understanding in glucose metabolism, insulin signalling mechanism, insulin resistance, oxidative stress, reactive oxygen species and glucose transporters at cellular and molecular levels. With the aid of the C2C12 model, recent studies revealed that insulin resistance has close relationship with various metabolic diseases in terms of disease progression, pathogenesis and therapeutic management. A holistic, safe and effective disease management is highly of interest. Therefore, significant efforts have been paid to explore novel drug compounds and natural herbs that can elicit therapeutic effects in the targeted sites at both cellular (e.g. mitochondria, glucose transporter) and molecular level (e.g. genes, signalling pathway). SUMMARY The use of C2C12 myoblast cell line is meaningful in pharmaceutical and biomedical research due to their expression of GLUT-4 and other features that are representative to human skeletal muscle cells. With the use of the C2C12 cell model, the impact of drug delivery systems (nanoparticles and quantum dots) on skeletal muscle, as well as the relationship between exercise, pancreatic β-cells and endothelial cells, was discovered.
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Affiliation(s)
- Chun Y Wong
- School of Pharmacy and Biomedical Science, Curtin University, Bentley, WA, Australia.,Curtin Health Innovation Research Institute, Bentley, WA, Australia
| | - Hani Al-Salami
- School of Pharmacy and Biomedical Science, Curtin University, Bentley, WA, Australia.,Curtin Health Innovation Research Institute, Bentley, WA, Australia.,Biotechnology and Drug Development Research Laboratory, Curtin University, Bentley, WA, Australia
| | - Crispin R Dass
- School of Pharmacy and Biomedical Science, Curtin University, Bentley, WA, Australia.,Curtin Health Innovation Research Institute, Bentley, WA, Australia
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12
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Hall C, Yu H, Choi E. Insulin receptor endocytosis in the pathophysiology of insulin resistance. Exp Mol Med 2020; 52:911-920. [PMID: 32576931 PMCID: PMC7338473 DOI: 10.1038/s12276-020-0456-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 05/11/2020] [Indexed: 12/16/2022] Open
Abstract
Insulin signaling controls cell growth and metabolic homeostasis. Dysregulation of this pathway causes metabolic diseases such as diabetes. Insulin signaling pathways have been extensively studied. Upon insulin binding, the insulin receptor (IR) triggers downstream signaling cascades. The active IR is then internalized by clathrin-mediated endocytosis. Despite decades of studies, the mechanism and regulation of clathrin-mediated endocytosis of IR remain incompletely understood. Recent studies have revealed feedback regulation of IR endocytosis through Src homology phosphatase 2 (SHP2) and the mitogen-activated protein kinase (MAPK) pathway. Here we review the molecular mechanism of IR endocytosis and its impact on the pathophysiology of insulin resistance, and discuss the potential of SHP2 as a therapeutic target for type 2 diabetes.
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Affiliation(s)
- Catherine Hall
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA
| | - Hongtao Yu
- Laboratory of Cell Biology, School of Life Sciences, Westlake University, Hangzhou, Zhejiang, 310024, China.
- Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA.
| | - Eunhee Choi
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY, 10032, USA.
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13
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Xiong R, Wang XL, Wu JM, Tang Y, Qiu WQ, Shen X, Teng JF, Pan R, Zhao Y, Yu L, Liu J, Chen HX, Qin DL, Yu CL, Wu AG. Polyphenols isolated from lychee seed inhibit Alzheimer's disease-associated Tau through improving insulin resistance via the IRS-1/PI3K/Akt/GSK-3β pathway. JOURNAL OF ETHNOPHARMACOLOGY 2020; 251:112548. [PMID: 31917277 DOI: 10.1016/j.jep.2020.112548] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 01/02/2020] [Accepted: 01/03/2020] [Indexed: 06/10/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Lychee seed, the seed of Litchi chinensis Sonn. is one of the commonly used in traditional Chinese medicine (TCM). It possesses many pharmacological effects such as blood glucose and lipid-lowering effects, liver protection, and antioxidation. Our preliminary studies have proven that an active fraction derived from lychee seed (LSF) can significantly decrease the blood glucose level, inhibit amyloid-β (Aβ) fibril formation and Tau hyperphosphorylation, and improve the cognitive function and behavior of Alzheimer's disease (AD) model rats. AIM OF THE STUDY The aim of this study was to identify the main active components in LSF that can inhibit the hyperphosphorylation of Tau through improving insulin resistance (IR) in dexamethasone (DXM)-induced HepG2 and HT22 cells. MATERIALS AND METHODS The isolation was guided by the bioactivity evaluation of the improvement effect of IR in HepG2 and HT22 cells. The mRNA and protein expressions of IRS-1, PI3K, Akt, GSK-3β, and Tau were measured by RT-PCR, Western blotting, and immunofluorescence methods, respectively. RESULTS After extraction, isolation, and elucidation using chromatography and spectrum technologies, three polyphenols including catechin, procyanidin A1 and procyanidin A2 were identified from fractions 3, 5, and 9 derived from LSF. These polyphenols inhibit hyperphosphorylated Tau via the up-regulation of IRS-1/PI3K/Akt and down-regulation of GSK-3β. Molecular docking result further demonstrate that these polyphenols exhibit good binding property with insulin receptor. CONCLUSIONS catechin, procyanidin A1, and procyanidin A2 are the main components in LSF that inhibit Tau hyperphosphorylation through improving IR via the IRS-1/PI3K/Akt/GSK-3β pathway. Therefore, the findings in the current study provide novel insight into the anti-AD mechanism of the components in LSF derived from lychee seed, which is valuable for the further development of a novel drug or nutrient supplement for the prevention and treatment of AD.
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Affiliation(s)
- Rui Xiong
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Xiu-Ling Wang
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Department of Pharmacy, Ministry of Education Key Laboratory of Child Development and Disorders, National Clinical Research Center for Child Health and Disorders, China International Science and Technology Cooperation base of Child development and Critical Disorders, Chongqing Key Laboratory of Pediatrics, Children's Hospital of Chongqing Medical University, Chongqing, China.
| | - Jian-Ming Wu
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Institute of Cardiovascular Research, The Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan, China.
| | - Yong Tang
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Wen-Qiao Qiu
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Xin Shen
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Department of Chinese Materia Medica, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China.
| | - Jin-Feng Teng
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Rong Pan
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Department of Human Anatomy, School of Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan, China.
| | - Ya Zhao
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Lu Yu
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Jian Liu
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Hai-Xia Chen
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China.
| | - Da-Lian Qin
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Institute of Cardiovascular Research, The Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan, China.
| | - Chong-Lin Yu
- Department of Human Anatomy, School of Preclinical Medicine, Southwest Medical University, Luzhou, Sichuan, China.
| | - An-Guo Wu
- Sichuan Key Laboratory of New Drug Discovery and Druggability Evaluation, Luzhou Key Laboratory of Bioactivity Screening in Traditional Chinese Medicine and Druggability Evalution, School of Pharmacy, Southwest Medical University, Luzhou, Sichuan, China; Institute of Cardiovascular Research, The Key Laboratory of Medical Electrophysiology, Ministry of Education of China, Collaborative Innovation Center for Prevention and Treatment of Cardiovascular Disease of Sichuan Province, Southwest Medical University, Luzhou, Sichuan, China.
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Disser NP, Sugg KB, Talarek JR, Sarver DC, Rourke BJ, Mendias CL. Insulin-like growth factor 1 signaling in tenocytes is required for adult tendon growth. FASEB J 2019; 33:12680-12695. [PMID: 31536390 DOI: 10.1096/fj.201901503r] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Tenocytes serve to synthesize and maintain collagen fibrils and other extracellular matrix proteins in tendon. Despite the high prevalence of tendon injury, the underlying biologic mechanisms of postnatal tendon growth and repair are not well understood. IGF1 plays an important role in the growth and remodeling of numerous tissues but less is known about IGF1 in tendon. We hypothesized that IGF1 signaling is required for proper tendon growth in response to mechanical loading through regulation of collagen synthesis and cell proliferation. To test this hypothesis, we conditionally deleted the IGF1 receptor (IGF1R) in scleraxis (Scx)-expressing tenocytes using a tamoxifen-inducible Cre-recombinase system and caused tendon growth in adult mice via mechanical overload of the plantaris tendon. Compared with control Scx-expressing IGF1R-positive (Scx:IGF1R+) mice, in which IGF1R is present in tenocytes, mice that lacked IGF1R in their tenocytes [Scx-expressing IGF1R-negative (Scx:IGF1RΔ) mice] demonstrated reduced cell proliferation and smaller tendons in response to mechanical loading. Additionally, we identified that both the PI3K/protein kinase B and ERK pathways are activated downstream of IGF1 and interact in a coordinated manner to regulate cell proliferation and protein synthesis. These studies indicate that IGF1 signaling is required for proper postnatal tendon growth and support the potential use of IGF1 in the treatment of tendon disorders.-Disser, N. P., Sugg, K. B., Talarek, J. R., Sarver, D. C., Rourke, B. J., Mendias, C. L. Insulin-like growth factor 1 signaling in tenocytes is required for adult tendon growth.
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Affiliation(s)
| | - Kristoffer B Sugg
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Section of Plastic and Reconstructive Surgery, Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Jeffrey R Talarek
- Hospital for Special Surgery, New York, New York, USA.,Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Dylan C Sarver
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Brennan J Rourke
- Hospital for Special Surgery, New York, New York, USA.,Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Christopher L Mendias
- Hospital for Special Surgery, New York, New York, USA.,Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA.,Department of Physiology and Biophysics, Weill Cornell Medical College, New York, New York, USA
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15
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Abruzzese GA, Heber MF, Ferrer MJ, Ferreira SR, Silva AF, Motta AB. Effects of in utero androgen excess and metformin treatment on hepatic functions. Mol Cell Endocrinol 2019; 491:110416. [PMID: 30880153 DOI: 10.1016/j.mce.2019.03.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/08/2019] [Accepted: 03/08/2019] [Indexed: 12/27/2022]
Abstract
This study aimed to evaluate the role of prenatal hyperandrogenization in liver functions and the extent of metformin as treatment. Pregnant rats were hyperandrogenized with subcutaneous testosterone (1mg/rat) between 16 and 19 of pregnancy. Prenatally hyperandrogenized (PH) female offspring displayed, at the adult life, two phenotypes; a PH irregular ovulatory phenotype (PHiov) and a PH anovulatory (PHanov) phenotype. From day 70 to the moment of sacrifice (90 days of age), 50% of the animals of each group received a daily oral dose of 50 mg/kg of metformin. We found that both PH phenotypes displayed a hepatic disruptions of insulin and glucose pathway and that metformin treatment reversed some of these alterations in a specific-phenotype manner. Our findings show, for the first time, that androgen excess in utero promotes hepatic dysfunctions and that metformin treatment is able to specifically reverse those hepatic alterations and sheds light on the possible mechanisms of metformin action.
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Affiliation(s)
- Giselle Adriana Abruzzese
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - María Florencia Heber
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - María José Ferrer
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - Silvana Rocío Ferreira
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - Aimé Florencia Silva
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina
| | - Alicia Beatriz Motta
- Laboratorio de Fisio-patología Ovárica, Centro de Estudios Farmacológicos y Botánicos (CEFYBO), Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET), Facultad de Medicina, Universidad de Buenos Aires (UBA), Paraguay 2155, CP1121, Ciudad Autónoma de Buenos Aires, Argentina.
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Choi E, Kikuchi S, Gao H, Brodzik K, Nassour I, Yopp A, Singal AG, Zhu H, Yu H. Mitotic regulators and the SHP2-MAPK pathway promote IR endocytosis and feedback regulation of insulin signaling. Nat Commun 2019; 10:1473. [PMID: 30931927 PMCID: PMC6443781 DOI: 10.1038/s41467-019-09318-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 02/25/2019] [Indexed: 12/17/2022] Open
Abstract
Insulin controls glucose homeostasis and cell growth through bifurcated signaling pathways. Dysregulation of insulin signaling is linked to diabetes and cancer. The spindle checkpoint controls the fidelity of chromosome segregation during mitosis. Here, we show that insulin receptor substrate 1 and 2 (IRS1/2) cooperate with spindle checkpoint proteins to promote insulin receptor (IR) endocytosis through recruiting the clathrin adaptor complex AP2 to IR. A phosphorylation switch of IRS1/2 orchestrated by extracellular signal-regulated kinase 1 and 2 (ERK1/2) and Src homology phosphatase 2 (SHP2) ensures selective internalization of activated IR. SHP2 inhibition blocks this feedback regulation and growth-promoting IR signaling, prolongs insulin action on metabolism, and improves insulin sensitivity in mice. We propose that mitotic regulators and SHP2 promote feedback inhibition of IR, thereby limiting the duration of insulin signaling. Targeting this feedback inhibition can improve insulin sensitivity. The mechanisms promoting insulin resistance at the receptor level are poorly understood. Here, Choi et al. show that mitotic proteins and the SHP2-MAPK pathway regulate receptor endocytosis and insulin signaling feedback, identifying a potential role for SHP2 inhibitors to treat diabetes.
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Affiliation(s)
- Eunhee Choi
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA
| | - Sotaro Kikuchi
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA
| | - Haishan Gao
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA
| | - Karolina Brodzik
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA
| | - Ibrahim Nassour
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Adam Yopp
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Amit G Singal
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Hao Zhu
- Children's Research Institute, Departments of Pediatrics and Internal Medicine, Center for Regenerative Science and Medicine, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, TX, 75390, USA
| | - Hongtao Yu
- Howard Hughes Medical Institute, Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX, 75390, USA.
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Zhang Y, Yang S, Zhang M, Wang Z, He X, Hou Y, Bai G. Glycyrrhetinic Acid Improves Insulin-Response Pathway by Regulating the Balance between the Ras/MAPK and PI3K/Akt Pathways. Nutrients 2019; 11:nu11030604. [PMID: 30871060 PMCID: PMC6470473 DOI: 10.3390/nu11030604] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/03/2019] [Accepted: 03/09/2019] [Indexed: 12/20/2022] Open
Abstract
Glycyrrhetinic acid (GA), a bioactive component in the human diet, has been reported to improve hyperglycemia, dyslipidemia, insulin resistance and obesity in rats with metabolic syndrome. However, GA-specific target proteins and the mechanisms involved in the downstream signaling and cross-talk to improve insulin sensitivity have not been fully elucidated. In this study, the potential targets of GA were identified by chemical proteomics strategies using serial GA probes for target fishing and cell molecular imaging. Intracellular enzyme activity evaluation and insulin resistance models were used for validating the function of the target proteins on the downstream insulin signaling pathways. Collectively, our data demonstrate that GA improved the insulin-responsive pathway and glucose consumption levels via multiple diabetogenic factors that activated the insulin signaling pathway in HepG2 cells. GA improved Glucose transporter 4(GLUT4) expression by targeting the Ras protein to regulate the mitogen-activated protein kinase (MAPK) pathway. GA exhibited a strong inhibitory effect on IRS1ser307 phosphorylation in cells treated with the Protein kinase C (PKC) activator Phorbol 12-myristate 13-acetate (PMA.) Consistently, IRS1ser307 phosphorylation was also inhibited by GA in Free fatty acid (FFA)-treated HepG2 cells. GA also inhibited the PMA-induced phosphorylation of IκB kinase α/β (IKKα/β), c-Jun N-terminal kinase (JNK) and p38 proteins (P38), suggesting that IKKα/β, JNK and P38 activation is dependent on PKC activity.
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Affiliation(s)
- Yuan Zhang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Shengnan Yang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Man Zhang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Zhihua Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Xin He
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Yuanyuan Hou
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
| | - Gang Bai
- State Key Laboratory of Medicinal Chemical Biology, College of Pharmacy and Tianjin Key Laboratory of Molecular Drug Research, Nankai University, Haihe Education Park, 38 Tongyan Road, Tianjin 300353, China.
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Wei Q, Pu X, Zhang L, Xu Y, Duan M, Wang Y. Expression of Dual-Specificity Phosphatase 9 in Placenta and Its Relationship with Gestational Diabetes Mellitus. J Diabetes Res 2019; 2019:1963178. [PMID: 31772940 PMCID: PMC6854249 DOI: 10.1155/2019/1963178] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 08/29/2019] [Accepted: 09/07/2019] [Indexed: 12/25/2022] Open
Abstract
INTRODUCTION The aim of the present study was to examine placental levels of DUSP9 mRNA and protein and to investigate the potential role of DUSP9 in the development of gestational diabetes mellitus (GDM). METHODS Placental tissues from pregnant women with GDM (n = 17) and normal healthy pregnant women (n = 16) were collected at delivery. The expression of DUSP9 mRNA in placental tissue was analyzed by real-time PCR, while the expression of DUPS9 protein was evaluated by immunohistochemistry and western blot. Differences in the expression levels of DUSP9 mRNA and protein between the two groups were assessed, as well as potential correlations between DUSP9 mRNA expression levels and relevant clinical indicators. RESULTS Blood glucose levels were significantly higher in the GDM group than in the control group, based on an oral glucose tolerance test. DUSP9 protein was expressed in the placental cytotrophoblasts in both groups, and placental levels of DUSP9 protein and mRNA were significantly higher in women with GDM. Placental DUSP9 mRNA levels in all 33 women correlated moderately with delivery gestational week (R = 0.465, P = 0.006), fasting plasma glucose (R = 0.350, P = 0.046), 1-hour postload plasma glucose (R = 0.363, P = 0.038), and 2-hour postload plasma glucose (R = 0.366, P = 0.036), but not with maternal age, preconception body mass index, prenatal body mass index, or neonatal birth weight. Multiple linear regression analysis indicated that delivery gestational week was an influence factor of DUSP9 mRNA levels (β 1 = 0.026, P < 0.05). CONCLUSIONS DUSP9 upregulation in the placenta of GDM pregnant women may promote insulin resistance, which may correlate with the occurrence of GDM. But there is still possibility that DUSP9 upregulation was the results of insulin resistance and/or hyperglycemia. Further research is needed to explore the role of DUSP9 in GDM.
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Affiliation(s)
- Qiang Wei
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
| | - Xiaomin Pu
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
| | - Li Zhang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
| | - Yi Xu
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
| | - Meifan Duan
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
| | - Yuemei Wang
- Department of Obstetrics and Gynecology, Key Laboratory of Birth Defects and Related Diseases of Women and Children of the Ministry of Education, West China Second Hospital, Sichuan University, Chengdu, China
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Suen KM, Lin CC, Seiler C, George R, Poncet-Montange G, Biter AB, Ahmed Z, Arold ST, Ladbury JE. Phosphorylation of threonine residues on Shc promotes ligand binding and mediates crosstalk between MAPK and Akt pathways in breast cancer cells. Int J Biochem Cell Biol 2018; 94:89-97. [PMID: 29208567 DOI: 10.1016/j.biocel.2017.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 11/16/2017] [Accepted: 11/30/2017] [Indexed: 01/14/2023]
Abstract
Scaffold proteins play important roles in regulating signalling network fidelity, the absence of which is often the basis for diseases such as cancer. In the present work, we show that the prototypical scaffold protein Shc is phosphorylated by the extracellular signal-regulated kinase, Erk. In addition, Shc threonine phosphorylation is specifically up-regulated in two selected triple-negative breast cancer (TNBC) cell lines. To explore how Erk-mediated threonine phosphorylation on Shc might play a role in the dysregulation of signalling events, we investigated how Shc affects pathways downstream of EGF receptor. Using an in vitro model and biophysical analysis, we show that Shc threonine phosphorylation is responsible for elevated Akt and Erk signalling, potentially through the recruitment of the 14-3-3 ζ and Pin-1 proteins.
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Affiliation(s)
- K M Suen
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Unit 1954, 1515 Holcombe Blvd, Houston, TX 77030, USA; Graduate School of Biological Sciences, The University of Texas MD Anderson Cancer Center, Unit 1954, 1515 Holcombe Blvd, Houston, TX 77030, USA
| | - C C Lin
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK
| | - C Seiler
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK
| | - R George
- Structural Biology STP, The Francis Crick Institute, Lincolns Inn Fields Laboratory, 44 Lincolns Inn Fields, Holborn, London, WC2A 3LY, UK
| | - G Poncet-Montange
- Orthogon Therapeutics, 960 Turnpike Street, Unit 10, Canton, MA 02021, USA
| | - A B Biter
- Sabin Vaccine Institute and Texas Children's Hospital Center for Vaccine Development, 1102 Bates Avenue, Houston, TX 77030, USA
| | - Z Ahmed
- Department of Biochemistry and Molecular Biology, The University of Texas MD Anderson Cancer Center, Unit 1954, 1515 Holcombe Blvd, Houston, TX 77030, USA
| | - S T Arold
- Division of Biological and Environmental Sciences and Engineering, CBRC, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | - J E Ladbury
- School of Molecular and Cellular Biology, University of Leeds, LC Miall Building, Leeds, LS2 9JT, UK.
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Ito S, Yanai M, Yamaguchi S, Couraud PO, Ohtsuki S. Regulation of Tight-Junction Integrity by Insulin in an In Vitro Model of Human Blood-Brain Barrier. J Pharm Sci 2017; 106:2599-2605. [PMID: 28456720 DOI: 10.1016/j.xphs.2017.04.036] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/14/2017] [Accepted: 04/17/2017] [Indexed: 12/30/2022]
Abstract
Although insulin receptor is expressed at the human blood-brain barrier (BBB), the physiological and pathologic roles of insulin signaling in biologic responses at the BBB remain unclear. Here, we investigate insulin signaling at the human BBB using human cerebral microvascular endothelial cell line (hCMEC/D3) as a well-established in vitro model. Western blot analysis showed that insulin induced phosphorylation of extracellular signal-regulated kinase and insulin receptor substrate-1 in hCMEC/D3 cells. Short-term insulin stimulation increased cell proliferation via the canonical phosphoinositide-3 kinase/protein kinase B and mitogen-activated protein kinase signaling pathways, suggesting that insulin signaling is involved in the regulation of biologic responses in the human BBB. We also found that insulin rapidly increased tight-junction integrity of hCMEC/D3 cells via the phosphoinositide-3 kinase/protein kinase B/glycogen synthase kinase-3 β signaling pathway. Inhibition of insulin/insulin-like growth factor-1 receptor kinase by AG1024 blocked the increase of tight-junction integrity. In addition, high-insulin/high-glucose treatment (as a model of hyperglycemia and hyperinsulinemia) synergistically reduced the tight-junction integrity in hCMEC/D3 cells, although either condition alone had little or no effect. Our findings suggest that, in addition to the established role of interactions of astrocytes and pericytes with brain capillary endothelial cells, insulin signaling from the blood side of the BBB contributes to maintenance of homeostasis by regulating cell proliferation and tight-junction integrity.
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Affiliation(s)
- Shingo Ito
- Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda, Tokyo 100-0004, Japan
| | - Mari Yanai
- Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Shunsuke Yamaguchi
- Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan
| | - Pierre-Olivier Couraud
- Institut Cochin, INSERM U1016, CNRS UMR8104, Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Sumio Ohtsuki
- Department of Pharmaceutical Microbiology, Faculty of Life Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, School of Pharmacy, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; Department of Pharmaceutical Microbiology, Graduate School of Pharmaceutical Sciences, Kumamoto University, 5-1 Oe-honmachi, Chuo-ku, Kumamoto 862-0973, Japan; AMED-CREST, Japan Agency for Medical Research and Development, 1-7-1 Otemachi, Chiyoda, Tokyo 100-0004, Japan.
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Regulation of insulin receptor phosphorylation in the brains of prenatally stressed rats: New insight into the benefits of antidepressant drug treatment. Eur Neuropsychopharmacol 2017; 27:120-131. [PMID: 28063625 DOI: 10.1016/j.euroneuro.2016.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 12/20/2016] [Accepted: 12/22/2016] [Indexed: 01/03/2023]
Abstract
A growing body of evidence supports the involvement of disturbances in the brain insulin pathway in the pathogenesis of depression. On the other hand, data concerning the impact of antidepressant drug therapy on brain insulin signaling remain scare and insufficient. We determinated the influence of chronic treatment with antidepressant drugs (imipramine, fluoxetine and tianeptine) on the insulin signaling pathway of the brain of adult prenatally stressed rats. 3-month-old prenatally stressed and control rats were treated for 21 days with imipramine, fluoxetine or tianeptine (10mg/kg/day i.p.).The impact of chronic antidepressant administration was examined in forced swim test. In the frontal cortex and hippocampus, the mRNA and protein expression of insulin, insulin receptor, insulin receptor substrates (IRS-1,IRS-2) and adaptor proteins (Shc1, Grb2) before and after drugs administration were measured.Rats exposed prenatally to stressful stimuli displayed depressive-like disturbances, which were attenuated by antidepressant drug administration. We did not reveal the impact of prenatal stress or antidepressant treatment on insulin and the insulin receptor expression in the examined structures. We revealed that diminished insulin receptor phosphorylation evoked by the prenatal stress procedure was attenuated by drugs treatment. We demonstrated that the favorable effect of antidepressans on insulin receptor phosphorylation in the frontal cortex was mainly related with the normalization of serine312 and tyrosine IRS-1 phosphorylation, while in the hippocampus, it was related with the adaptor proteins Shc1/Grb2. It can be suggested that the behavioral effectiveness of antidepressant drug therapy may be related with the beneficial impact of antidepressant on insulin receptor phosphorylation pathways.
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Poloz Y, Dowling RJO, Stambolic V. Fundamental Pathways in Breast Cancer 1: Signaling from the Membrane. Breast Cancer 2017. [DOI: 10.1007/978-3-319-48848-6_1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Abstract
A continuous supply of glucose is necessary to ensure proper function and survival of all organs. Plasma glucose levels are thus maintained in a narrow range around 5 mM, which is considered the physiological set point. Glucose homeostasis is controlled primarily by the liver, fat, and skeletal muscle. Following a meal, most glucose disposals occur in the skeletal muscle, whereas fasting plasma glucose levels are determined primarily by glucose output from the liver. The balance between the utilization and production of glucose is primarily maintained at equilibrium by two opposing hormones, insulin and glucagon. In response to an elevation in plasma glucose and amino acids (after consumption of a meal), insulin is released from the beta cells of the islets of Langerhans in the pancreas. When plasma glucose falls (during fasting or exercise), glucagon is secreted by α cells, which surround the beta cells in the pancreas. Both cell types are extremely sensitive to glucose concentrations, can regulate hormone synthesis, and are released in response to small changes in plasma glucose levels. At the same time, insulin serves as the major physiological anabolic agent, promoting the synthesis and storage of glucose, lipids, and proteins and inhibiting their degradation and release back into the circulation. This chapter will focus mainly on signal transduction mechanisms by which insulin exerts its plethora of effects in liver, muscle, and fat cells, focusing on those pathways that are crucial in the control of glucose and lipid homeostasis.
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Affiliation(s)
- Alan R Saltiel
- Life Sciences Institute, University of Michigan, AnnArbor, MI, USA.
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Co-activator binding protein PIMT mediates TNF-α induced insulin resistance in skeletal muscle via the transcriptional down-regulation of MEF2A and GLUT4. Sci Rep 2015; 5:15197. [PMID: 26468734 PMCID: PMC4606566 DOI: 10.1038/srep15197] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/21/2015] [Indexed: 12/18/2022] Open
Abstract
The mechanisms underlying inflammation induced insulin resistance are poorly understood. Here, we report that the expression of PIMT, a transcriptional co-activator binding protein, was up-regulated in the soleus muscle of high sucrose diet (HSD) induced insulin resistant rats and TNF-α exposed cultured myoblasts. Moreover, TNF-α induced phosphorylation of PIMT at the ERK1/2 target site Ser298. Wild type (WT) PIMT or phospho-mimic Ser298Asp mutant but not phospho-deficient Ser298Ala PIMT mutant abrogated insulin stimulated glucose uptake by L6 myotubes and neonatal rat skeletal myoblasts. Whereas, PIMT knock down relieved TNF-α inhibited insulin signaling. Mechanistic analysis revealed that PIMT differentially regulated the expression of GLUT4, MEF2A, PGC-1α and HDAC5 in cultured cells and skeletal muscle of Wistar rats. Further characterization showed that PIMT was recruited to GLUT4, MEF2A and HDAC5 promoters and overexpression of PIMT abolished the activity of WT but not MEF2A binding defective mutant GLUT4 promoter. Collectively, we conclude that PIMT mediates TNF-α induced insulin resistance at the skeletal muscle via the transcriptional modulation of GLUT4, MEF2A, PGC-1α and HDAC5 genes.
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The Interplay of Akt and ERK in Aβ Toxicity and Insulin-Mediated Protection in Primary Hippocampal Cell Culture. J Mol Neurosci 2015; 57:325-34. [PMID: 26266487 DOI: 10.1007/s12031-015-0622-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 07/14/2015] [Indexed: 01/11/2023]
Abstract
It is not known if insulin prevents Aβ-induced cell death, MAPK, and Akt activity in isolated hippocampal cell culture. This study was aimed to explore the effect of insulin on Aβ-induced cell death and ERK and Akt signaling alteration in isolated hippocampal cell culture. Additionally, it was desirable to assess if there is any interaction between these two pathways. The hippocampal cells were derived from fetuses at the embryonic day 18-19. The cells were treated with different drugs, and MTT assay, morphological assessments, and Western blot were done. Insulin prevented Aβ-induced cell death and caspase-3 cleavage. Aβ-induced toxicity was aligned with decrement of the phosphorylated Akt (pAkt) which was prevented by insulin. The PI3 kinase inhibitor, LY294002, decreased pAkt and abolished the protective effect of insulin. Aβ exposure increased phosphorylated ERK (pERK) in parallel with cell death and apoptosis. Insulin-inhibited ERK activation (phosphorylation) induced by Aβ and PD98059 (as ERK inhibitor) did not affect the protective effect of insulin. One of the interesting finding of this study was the interplay of Akt and ERK in Aβ toxicity and insulin-mediated protection; meaning that there is an inverse relation between pERK and pAkt, in a way that PI3-Akt pathway inhibition leads to pERK increment while ERK inhibition causes Akt phosphorylation (activation). This study showed, for the first time, that insulin protects against Aβ toxicity in isolated hippocampal cell culture via modulating Akt and ERK phosphorylation and also revealed an interaction between those signals in Aβ toxicity and insulin-mediated protection.
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Roles of obese-insulin resistance and anti-diabetic drugs on the heart with ischemia-reperfusion injury. Cardiovasc Drugs Ther 2015; 28:549-62. [PMID: 25283086 DOI: 10.1007/s10557-014-6553-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The incidence of obesity with insulin resistance is increasing worldwide. This condition is also known as a risk factor of coronary artery disease and associated with increased arrhythmias, impaired left ventricular function, and increased infarct size during cardiac ischemia-reperfusion (I/R) injury. The proposed mechanisms are due to impaired glucose utilization and pro-survival signaling molecules, and increased inflammatory cytokines, which have been demonstrated in the I/R hearts in various models of obese-insulin resistance. However, the cardiac effects of diets in the I/R heart are still unsettled since several studies reported that high-caloric diet consumption might protect the heart from I/R injury. Although several therapeutic strategies such as anti-diabetic drugs, natural compounds as well as treadmill exercise have been proposed to exert cardioprotection in the I/R heart in obese-insulin resistant animals, some interventions including ischemic post-conditioning failed to protect the heart from I/R injury. In this comprehensive review, reports from both genetic deletion and dietary-induced obese-insulin resistant animal models regarding the effects of obese-insulin resistance on metabolic parameters, cardiac function, infarct size, and molecular mechanisms under I/R injury are summarized. Moreover, the effects of anti-diabetic drugs and other pharmacological interventions on these parameters in an obese-insulin resistant model under I/R injury are also comprehensively summarized and discussed.
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Satyanarayana K, Sravanthi K, Shaker IA, Ponnulakshmi R. Molecular approach to identify antidiabetic potential of Azadirachta indica. J Ayurveda Integr Med 2015; 6:165-74. [PMID: 26604551 PMCID: PMC4630690 DOI: 10.4103/0975-9476.157950] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 05/14/2014] [Accepted: 06/28/2014] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Azadirachta indica (Neem) is a medicinal plant, used in Ayurveda for treating various diseases, one of which is diabetes mellitus. It is known to possess antiinflammatory, antipyretic, antimicrobial, antidiabetic and diverse pharmacological properties. However, the molecular mechanism underlying the effect of A. indica on insulin signal transduction and glucose homeostasis is obscure. OBJECTIVE The aim was to study the effects of A. indica aqueous leaf extract on the expression of insulin signaling molecules and glucose oxidation in target tissue of high-fat and fructose-induced type-2 diabetic male rat. MATERIALS AND METHODS The oral effective dose of A. indica leaf extract (400 mg/kg body weight [b.wt]) was given once daily for 30 days to high-fat diet-induced diabetic rats. At the end of the experimental period, fasting blood glucose, oral glucose tolerance, serum lipid profile, and the levels of insulin signaling molecules, glycogen, glucose oxidation in gastrocnemius muscle were assessed. RESULTS Diabetic rats showed impaired glucose tolerance and impairment in insulin signaling molecules (insulin receptor, insulin receptor substrate-1, phospho-IRS-1(Tyr632), phospho-IRS-1(Ser636), phospho-Akt(Ser473), and glucose transporter 4 [GLUT4] proteins), glycogen concentration and glucose oxidation. The treatment with A. indica leaf extract normalized the altered levels of blood glucose, serum insulin, lipid profile and insulin signaling molecules as well as GLUT4 proteins at 400 mg/kg b.wt dose. CONCLUSION It is concluded from the present study that A. indica may play a significant role in the management of type-2 diabetes mellitus, by improving the insulin signaling molecules and glucose utilization in the skeletal muscle.
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Affiliation(s)
- K. Satyanarayana
- Department of Medical Biochemistry, Bharath University, Selaiyur, Chennai, India
| | - K. Sravanthi
- Department of Pharmacology, Sakshi Medical College and Research Centre, Myana, Chennai, India
| | - I. Anand Shaker
- Department of Medical Biochemistry, Bharath University, Selaiyur, Chennai, India
| | - R. Ponnulakshmi
- Department of Zoology, Ethiraj College for Women, Chennai, India
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Jaiswal N, Maurya CK, Pandey J, Rai AK, Tamrakar AK. Fructose-induced ROS generation impairs glucose utilization in L6 skeletal muscle cells. Free Radic Res 2015; 49:1055-68. [PMID: 25968943 DOI: 10.3109/10715762.2015.1031662] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
High fructose consumption has implicated in insulin resistance and metabolic syndrome. Fructose is a highly lipogenic sugar that has intense metabolic effects in liver. Recent evidences suggest that fructose exposure to other tissues has substantial and profound metabolic consequences predisposing toward chronic conditions such as type 2 diabetes. Since skeletal muscle is the major site for glucose utilization, in the present study we define the effects of fructose exposure on glucose utilization in skeletal muscle cells. Upon fructose exposure, the L6 skeletal muscle cells displayed diminished glucose uptake, glucose transporter type 4 (GLUT4) translocation, and impaired insulin signaling. The exposure to fructose elevated reactive oxygen species (ROS) production in L6 myotubes, accompanied by activation of the stress/inflammation markers c-Jun N-terminal kinase (JNK) and extracellular signal-regulated kinase 1/2 (ERK1/2), and degradation of inhibitor of NF-κB (IκBα). We found that fructose caused impairment of glucose utilization and insulin signaling through ROS-mediated activation of JNK and ERK1/2 pathways, which was prevented in the presence of antioxidants. In conclusion, our data demonstrate that exposure to fructose induces cell-autonomous oxidative response through ROS production leading to impaired insulin signaling and attenuated glucose utilization in skeletal muscle cells.
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Affiliation(s)
- N Jaiswal
- Division of Biochemistry, CSIR-Central Drug Research Institute , Lucknow, Uttar Pradesh , India
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29
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O'Brien L, Hosick PA, John K, Stec DE, Hinds TD. Biliverdin reductase isozymes in metabolism. Trends Endocrinol Metab 2015; 26:212-20. [PMID: 25726384 PMCID: PMC4380527 DOI: 10.1016/j.tem.2015.02.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/28/2015] [Accepted: 02/01/2015] [Indexed: 12/17/2022]
Abstract
The biliverdin reductase (BVR) isozymes BVRA and BVRB are cell surface membrane receptors with pleiotropic functions. This review compares, for the first time, the structural and functional differences between the isozymes. They reduce biliverdin, a byproduct of heme catabolism, to bilirubin, display kinase activity, and BVRA, but not BVRB, can act as a transcription factor. The binding motifs present in the BVR isozymes allow a wide range of interactions with components of metabolically important signaling pathways such as the insulin receptor kinase cascades, protein kinases (PKs), and inflammatory mediators. In addition, serum bilirubin levels have been negatively associated with abdominal obesity and hypertriglyceridemia. We discuss the roles of the BVR isozymes in metabolism and their potential as therapeutic targets.
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Affiliation(s)
- Luke O'Brien
- Center for Hypertension and Personalized Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA
| | - Peter A Hosick
- Department of Exercise Science and Physical Education, Montclair State University, Montclair, NJ 07043, USA
| | - Kezia John
- Center for Hypertension and Personalized Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA
| | - David E Stec
- Center for Excellence in Cardiovascular-Renal Research, Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA
| | - Terry D Hinds
- Center for Hypertension and Personalized Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, OH 43614, USA.
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30
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Sankar P, Zachariah B, Vickneshwaran V, Jacob SE, Sridhar MG. Amelioration of oxidative stress and insulin resistance by soy isoflavones (from Glycine max) in ovariectomized Wistar rats fed with high fat diet: the molecular mechanisms. Exp Gerontol 2015; 63:67-75. [PMID: 25660477 DOI: 10.1016/j.exger.2015.02.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 12/08/2014] [Accepted: 02/04/2015] [Indexed: 12/11/2022]
Abstract
Estrogen deficiency after menopause accelerates the redox imbalance and insulin signaling, leading to oxidative stress (OS) and insulin resistance (IR). The molecular mechanisms by which the loss of ovarian hormone leads to OS and IR remain unclear. In the present study we found that rats when subjected to ovariectomy (OVX) resulted in reduction of whole blood antioxidants and elevation of oxidant markers. The expression of anti-oxidant enzymes, superoxide dismutase (SOD1) and glutathione peroxidase (GPX1) was suppressed whereas the pro-oxidative enzyme NADPH oxidase (NOX4) and mitogen activated protein (MAP) kinases ERK 1/2 and p38 were increased at different tissues. Treatment with soy (SIF, 150 mg/kg BW for 12 weeks) extract markedly reversed these metabolic changes and improved OS. Ovariectomized rats also displayed glucose intolerance (GI) and IR as evident from the impaired glucose tolerance test, and reduced expression of adipose and hepatic insulin receptor beta (IRβ) and adipose tissue GLUT4. Treatment with SIF reversed the ovariectomy induced GI and IR. On the other hand, all these metabolic changes were further augmented when ovariectomy was followed by a high fat diet, and these changes were also reversed by SIF. Taken together, these findings emphasized the antioxidant property and anti-diabetic effects of soy isoflavones suggesting the use of this natural phytoestrogen as a strategy for relieving oxidative stress and insulin resistance in postmenopausal women.
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Affiliation(s)
- P Sankar
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605 006, India.
| | - Bobby Zachariah
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605 006, India.
| | - V Vickneshwaran
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605 006, India
| | - Sajini Elizabeth Jacob
- Department of Pathology, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605 006, India
| | - M G Sridhar
- Department of Biochemistry, Jawaharlal Institute of Postgraduate Medical Education and Research (JIPMER), Puducherry 605 006, India
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Banks AS, McAllister FE, Camporez JPG, Zushin PJH, Jurczak MJ, Laznik-Bogoslavski D, Shulman GI, Gygi SP, Spiegelman BM. An ERK/Cdk5 axis controls the diabetogenic actions of PPARγ. Nature 2014; 517:391-5. [PMID: 25409143 PMCID: PMC4297557 DOI: 10.1038/nature13887] [Citation(s) in RCA: 225] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2014] [Accepted: 09/22/2014] [Indexed: 02/06/2023]
Abstract
Obesity-linked insulin resistance is a major precursor to the development of type 2 diabetes. Previous work has shown that phosphorylation of PPARγ at serine 273 by Cdk5 stimulates diabetogenic gene expression in adipose tissues1. Inhibition of this modification is a key therapeutic mechanism for anti-diabetic PPARγ ligand drugs, such as the thiazolidinediones and PPARγ partial/non-agonists2. To better understand the importance of this obesity-linked PPARγ phosphorylation, we created mice that ablated Cdk5 specifically in adipose tissues. Surprisingly, these mice have both a paradoxical increase in PPARγ phosphorylation at S273 and worsened insulin resistance. Unbiased proteomic studies show that ERK kinases are activated in these KO animals. We show here that ERK directly phosphorylates S273 of PPARγ in a robust manner and that Cdk5 suppresses ERKs through direct action on a novel site in MEK, the ERK kinase. Importantly, pharmacological MEK and ERK inhibition markedly improves insulin resistance in both obese wild type and ob/ob mice, and also completely reverses the deleterious effects of the Cdk5 ablation. These data show that an ERK/Cdk5 axis controls PPARγ function and suggest that MEK/ERK inhibitors may hold promise for the treatment of type 2 diabetes.
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Affiliation(s)
- Alexander S Banks
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Fiona E McAllister
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - João Paulo G Camporez
- Yale Mouse Metabolic Phenotyping Center and Departments of Internal Medicine and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Peter-James H Zushin
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Michael J Jurczak
- Yale Mouse Metabolic Phenotyping Center and Departments of Internal Medicine and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | | | - Gerald I Shulman
- Yale Mouse Metabolic Phenotyping Center and Departments of Internal Medicine and Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Steven P Gygi
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Bruce M Spiegelman
- 1] Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA [2] Dana-Farber Cancer Institute, Boston, Massachusetts 02115, USA
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Free fatty acid induced impairment of insulin signaling is prevented by the diastereomeric mixture of calophyllic acid and isocalophyllic acid in skeletal muscle cells. Eur J Pharmacol 2014; 746:70-7. [PMID: 25445050 DOI: 10.1016/j.ejphar.2014.10.049] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/27/2014] [Accepted: 10/29/2014] [Indexed: 12/15/2022]
Abstract
Elevated fatty acid levels play a pathogenic role in the development of insulin resistance, associated with type 2 diabetes. Interventions with ability to ameliorate fatty acid-induced insulin resistance might be useful for the management of diabetes. Here, we explored the effect of the diastereomeric mixture of calophyllic acid and isocalophyllic acid (F015) on palmitate-induced insulin resistance in skeletal muscle cells. An incubation of L6 myotubes with palmitate inhibited insulin-stimulated glucose uptake and translocation of GLUT4 to cell surface. Addition of F015 strongly prevented these inhibitions. Furthermore, F015 effectively inhibited the ability of palmitate to reduce insulin-stimulated phosphorylation of IRS-1, AKT and GSK-3β in L6 myotubes. F015 presented a strong inhibition on palmitate-induced production of reactive oxygen species and associated inflammation, as the activation JNK, ERK1/2 and p38 MAPK were greatly reduced. F015 also inhibited inflammation-stimulated IRS-1 serine phosphorylation and restored insulin-stimulated IRS-1 tyrosine phosphorylation in presence of palmitate, resulted in enhanced insulin sensitivity. Results suggest that F015 inhibits palmitate-induced, reactive oxygen species-associated MAPK kinase activation and restored insulin sensitivity through regulating IRS-1 function. All these indicate F015 to be a potentially therapeutic candidate for insulin resistance and type 2 diabetes.
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Maurya CK, Singh R, Jaiswal N, Venkateswarlu K, Narender T, Tamrakar AK. 4-Hydroxyisoleucine ameliorates fatty acid-induced insulin resistance and inflammatory response in skeletal muscle cells. Mol Cell Endocrinol 2014; 395:51-60. [PMID: 25109277 DOI: 10.1016/j.mce.2014.07.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 07/02/2014] [Accepted: 07/28/2014] [Indexed: 02/06/2023]
Abstract
The 4-hydroxyisoleucine (4-HIL), an unusual amino acid isolated from the seeds of Trigonella foenum-graecum was investigated for its metabolic effects to ameliorate free fatty acid-induced insulin resistance in skeletal muscle cells. An incubation of L6 myotubes with palmitate inhibited insulin stimulated-glucose uptake and -translocation of glucose transporter 4 (GLUT4) to the cell surface. Addition of 4-HIL strongly prevented this inhibition. We then examined the insulin signaling pathway, where 4-HIL effectively inhibited the ability of palmitate to reduce insulin-stimulated phosphorylation of insulin receptor substrate-1 (IRS-1), protein kinase B (PKB/AKT), AKT substrate of 160 kD (AS160) and glycogen synthase kinase 3β (GSK-3β) in L6 myotubes. Moreover, 4-HIL presented strong inhibition on palmitate-induced production of reactive oxygen species (ROS) and associated inflammation, as the activation of NF-κB, JNK1/2, ERK1/2 and p38 MAPK was greatly reduced. 4-HIL also inhibited inflammation-stimulated IRS-1 serine phosphorylation and restored insulin-stimulated IRS-1 tyrosine phosphorylation in the presence of palmitate, leading to enhanced insulin sensitivity. These findings suggested that 4-HIL could inhibit palmitate-induced, ROS-associated inflammation and restored insulin sensitivity through regulating IRS-1 function.
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Affiliation(s)
- Chandan Kumar Maurya
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Rohit Singh
- Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Natasha Jaiswal
- Division of Biochemistry, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - K Venkateswarlu
- Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031, India
| | - Tadigoppula Narender
- Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031, India.
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Dai J, Bercury KK, Macklin WB. Interaction of mTOR and Erk1/2 signaling to regulate oligodendrocyte differentiation. Glia 2014; 62:2096-109. [PMID: 25060812 DOI: 10.1002/glia.22729] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 07/10/2014] [Accepted: 07/10/2014] [Indexed: 01/22/2023]
Abstract
A multitude of factors regulate oligodendrocyte differentiation and remyelination, and to elucidate the mechanisms underlying this process, we analyzed the interactions of known signaling pathways involved in these processes. Previous work from our lab and others shows that Akt, mTOR, and Erk 1/2 are major signaling pathways regulating oligodendrocyte differentiation and myelination in vitro and in vivo. However, the relative contribution of the different pathways has been difficult to establish because the impact of inhibiting one pathway in in vitro cell culture models or in vivo may alter signaling through the other pathway. These studies were undertaken to clarify the interactions between these major pathways and understand more specifically the crosstalk between them. Oligodendrocyte differentiation in vitro required Akt, mTOR, and Erk 1/2 signaling, as inhibition of Akt, mTOR, or Erk 1/2 resulted in a significant decrease of myelin basic protein mRNA and protein expression. Interestingly, while inhibition of the Erk1/2 pathway had little impact on Akt/mTOR signaling, inhibition of the Akt/mTOR pathways significantly increased Erk1/2 signaling, although not enough to overcome the loss of Akt/mTOR signaling in the regulation of oligodendrocyte differentiation. Furthermore, such crosstalk was also noted in an in vivo context, after mTOR inhibition by rapamycin treatment of perinatal pups. GLIA 2014;62:2096-2109.
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Affiliation(s)
- JinXiang Dai
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado
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35
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Effect of troxerutin on insulin signaling molecules in the gastrocnemius muscle of high fat and sucrose-induced type-2 diabetic adult male rat. Mol Cell Biochem 2014; 395:11-27. [PMID: 24880482 DOI: 10.1007/s11010-014-2107-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/15/2014] [Indexed: 01/01/2023]
Abstract
Troxerutin is a trihydroxyethylated derivative of the flavonoid, rutin. It has been reported to possess the hepatoprotective, nephroprotective, antioxidant, anti-inflammatory, and antihyperlipidemic activities. Troxerutin treatment reduced the blood glucose and glycosylated hemoglobin levels in high-cholesterol-induced insulin-resistant mice and in type-2 diabetic patients. However, the mechanism by which it exhibits antidiabetic property was unknown. Therefore, the present study was designed to evaluate the effect of troxerutin on insulin signaling molecules in gastrocnemius muscle of high fat and sucrose-induced type-2 diabetic rats. Wistar male albino rats were selected and divided into five groups. Group I: Control. Group II: High fat and sucrose-induced type-2 diabetic rats. Group III: Type-2 diabetic rats treated with troxerutin (150 mg/kg body weight/day orally). Group IV: Type-2 diabetic rats treated with metformin (50 mg/kg body weight/day orally). Group V: Normal rats treated with troxerutin (150 mg/kg body weight/day orally). After 30 days of treatment, fasting blood glucose, oral glucose tolerance, serum lipid profile, and the levels of insulin signaling molecules, glycogen, glucose uptake, and oxidation in gastrocnemius muscle were assessed. Diabetic rats showed impairment in insulin signaling molecules (IR, p-IRS-1(Tyr632), p-Akt(Ser473), β-arrestin-2, c-Src, p-AS160(Thr642), and GLUT4 proteins), glycogen concentration, glucose uptake, and oxidation. Oral administration of troxerutin showed near normal levels of blood glucose, serum insulin, lipid profile, and insulin signaling molecules as well as GLUT4 proteins in type-2 diabetic rats. It is concluded from the present study that troxerutin may play a significant role in the management of type-2 diabetes mellitus, by improving the insulin signaling molecules and glucose utilization in the skeletal muscle.
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Ohne Y, Toyoshima Y, Kato H. Disruption of the Availability of Amino Acids Induces a Rapid Reduction of Serine Phosphorylation of Insulin Receptor Substrate-1in Vivoandin Vitro. Biosci Biotechnol Biochem 2014; 69:989-98. [PMID: 15914920 DOI: 10.1271/bbb.69.989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Insulin receptor substrate-1 (IRS-1) plays a pivotal role in insulin signal transduction. It has been shown that the amino acids modulate insulin signaling at the level of IRS-1. Here we show that an amino acid unbalanced diet causes a reduction in serine phosphorylation as well as an elevation in insulin-induced tyrosine phosphorylation of IRS-1 in rat muscle. In fibroblasts and myotube cells, the effect of amino acid deprivation on IRS-1 phosphorylation was evident only when cells were pretreated with reagents causing hyperphosphorylation of serines of IRS-1. But, the target kinases of these reagents were not inactivated by amino acid deprivation, suggesting that amino acid deprivation activates serine/threonine phosphatase(s) of IRS-1. The phosphatases regulated by mammalian target of rapamycin do not appear to participate in the dephosphorylation either. These results suggest that amino acid deprivation dephosphorylates IRS-1 through unidentified serine/threonine phosphatases and thereby potentiates insulin signaling.
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Affiliation(s)
- Yoichiro Ohne
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo
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Zhu Y, Hu Y, Huang T, Zhang Y, Li Z, Luo C, Luo Y, Yuan H, Hisatome I, Yamamoto T, Cheng J. High uric acid directly inhibits insulin signalling and induces insulin resistance. Biochem Biophys Res Commun 2014; 447:707-14. [PMID: 24769205 DOI: 10.1016/j.bbrc.2014.04.080] [Citation(s) in RCA: 187] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2014] [Accepted: 04/15/2014] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND AIM Accumulating clinical evidence suggests that hyperuricemia is strongly associated with abnormal glucose metabolism and insulin resistance. However, how high uric acid (HUA) level causes insulin resistance remains unclear. We aimed to determine the direct role of HUA in insulin resistance in vitro and in vivo in mice. METHODS An acute hyperuricemia mouse model was created by potassium oxonate treatment, and the impact of HUA level on insulin resistance was investigated by glucose tolerance test, insulin tolerance test and insulin signalling, including phosphorylation of insulin receptor substrate 1 (IRS1) and Akt. HepG2 cells were exposed to HUA treatment and N-acetylcysteine (NAC), reactive oxygen species scavenger; IRS1 and Akt phosphorylation was detected by Western blot analysis after insulin treatment. RESULTS Hyperuricemic mice showed impaired glucose tolerance with insulin resistance. Hyperuricemia inhibited phospho-Akt (Ser473) response to insulin and increased phosphor-IRS1 (Ser307) in liver, muscle and fat tissues. HUA induced oxidative stress, and the antioxidant NAC blocked HUA-induced IRS1 activation and Akt inhibition in HepG2 cells. CONCLUSION This study supplies the first evidence of HUA directly inducing insulin resistance in vivo and in vitro. Increased uric acid level may inhibit IRS1 and Akt insulin signalling and induce insulin resistance. The reactive oxygen species pathway plays a key role in HUA-induced insulin resistance.
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Affiliation(s)
- Yuzhang Zhu
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yaqiu Hu
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Tianliang Huang
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yongneng Zhang
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Zhi Li
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Chaohuan Luo
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Yinfeng Luo
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Huier Yuan
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China
| | - Ichiro Hisatome
- Division of Regenerative Medicine and Therapeutics, Institute of Regenerative Medicine and Biofunction, Graduate School of Medical Sciences, Tottori University, Yonago, Japan
| | - Tetsuya Yamamoto
- Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Jidong Cheng
- Department of Internal Medicine, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
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Li X, Zhao G, Ma B, Li R, Hong J, Liu S, Wang DW. 20-Hydroxyeicosatetraenoic acid impairs endothelial insulin signaling by inducing phosphorylation of the insulin receptor substrate-1 at Ser616. PLoS One 2014; 9:e95841. [PMID: 24763529 PMCID: PMC3998975 DOI: 10.1371/journal.pone.0095841] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 03/31/2014] [Indexed: 11/18/2022] Open
Abstract
20-hydroxyeicosatetraenoic acid (20-HETE) induces endothelial dysfunction and is correlated with diabetes. This study was designed to investigate the effects of 20-HETE on endothelial insulin signaling.Human umbilical vein endothelial cells (HUVECs) or C57BL/6J mice were treated with 20-HETE in the presence or absence of insulin, and p-ERK1/2, p-JNK, IRS-1/PI3K/AKT/eNOS pathway, were examined in endothelial cells and aortas by immunoblotting. eNOS activity and nitric oxide production were measured. 20-HETE increased ERK1/2 phosphorylation and IRS-1 phosphorylation at Ser616; these effects were reversed by ERK1/2 inhibition. We further observed that 20-HETE treatment resulted in impaired insulin-stimulated IRS-1 phosphorylation at Tyr632 and subsequent PI3-kinase/Akt activation. Furthermore, 20-HETE treatment blocked insulin-stimulated phosphorylation of eNOS at the stimulatory Ser1177 site, eNOS activation and NO production; these effects were reversed by inhibiting ERK1/2. Treatment of C57BL/6J mice with 20-HETE resulted in ERK1/2 activation and impaired insulin-dependent activation of the IRS-1/PI3K/Akt/eNOS pathway in the aorta. Our data suggest that the 20-HETE activation of IRS-1 phosphorylation at Ser616 is dependent on ERK1/2 and leads to impaired insulin-stimulated vasodilator effects that are mediated by the IRS-1/PI3K/AKT/eNOS pathway.
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Affiliation(s)
- Xuguang Li
- Department of Cardiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
- * E-mail:
| | - Gang Zhao
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Ben Ma
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Rui Li
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Jiang Hong
- Department of Cardiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Shaowen Liu
- Department of Cardiology, Shanghai First People's Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, People's Republic of China
| | - Dao Wen Wang
- Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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Ferreira GD, Germeyer A, de Barros Machado A, do Nascimento TL, Brum IS, Strowitzki T, von Eye Corleta H, Capp E. Are growth factor receptors modulated by metformin in human endometrial stromal cells after stimulation with androgen and insulin? Arch Gynecol Obstet 2014; 290:361-7. [PMID: 24627035 DOI: 10.1007/s00404-014-3197-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Accepted: 02/27/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVE To assess the effect of metformin on gene and protein expression of insulin receptor (IR) and IGF-1 (IGF-1R) receptor in human endometrial stromal cells after stimulation with androgen and insulin. STUDY DESIGN Primary culture of endometrial stromal cells stimulated with estrogen, progesterone with or without androgen or insulin, and treated with metformin for 24 and 48 h, followed by RNA (qRT-PCR) and protein (Western blot) extraction and analysis. RESULTS IR gene expression was increased after treatment with insulin (2.9-fold change, p = 0.027) and further after metformin treatment (4.7-fold change, p < 0.001), and in IGF-1R, the group treated with insulin (1.83-fold change) and metformin (1.78-fold change) showed more expression, than control group (p < 0.001). Similarly, IR protein expression was increased after addition of metformin and insulin (249,869 ± 15,878) in relation to the other groups (p < 0.001). Furthermore, cells treated with insulin (153,634 ± 29,123) and androgen plus insulin (162,854 ± 86,258) had a higher IR protein expression compared to control (104,654 ± 5,634) and androgen group (71,595 ± 3,439, (p = 0.045 and 0.021). In groups treated with insulin (127,711 ± 4,591) and androgen plus insulin (151,098 ± 5,194) the protein IGF-1R was increased compared to control (79,355 ± 3,470) and the androgen-only group (79,326 ± 3,114) (p < 0.001). CONCLUSION Metformin in combination with insulin increased IR protein and gene expressions, while it had no influence on the protein expression of IGF-1R in endometrial stromal cells.
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Affiliation(s)
- Gustavo Dias Ferreira
- Laboratório de Biologia Molecular Endócrina e Tumoral, Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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Boucher J, Kleinridders A, Kahn CR. Insulin receptor signaling in normal and insulin-resistant states. Cold Spring Harb Perspect Biol 2014; 6:6/1/a009191. [PMID: 24384568 DOI: 10.1101/cshperspect.a009191] [Citation(s) in RCA: 917] [Impact Index Per Article: 91.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In the wake of the worldwide increase in type-2 diabetes, a major focus of research is understanding the signaling pathways impacting this disease. Insulin signaling regulates glucose, lipid, and energy homeostasis, predominantly via action on liver, skeletal muscle, and adipose tissue. Precise modulation of this pathway is vital for adaption as the individual moves from the fed to the fasted state. The positive and negative modulators acting on different steps of the signaling pathway, as well as the diversity of protein isoform interaction, ensure a proper and coordinated biological response to insulin in different tissues. Whereas genetic mutations are causes of rare and severe insulin resistance, obesity can lead to insulin resistance through a variety of mechanisms. Understanding these pathways is essential for development of new drugs to treat diabetes, metabolic syndrome, and their complications.
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Affiliation(s)
- Jérémie Boucher
- Section on Integrative Physiology and Metabolism, Joslin Diabetes Center and Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115
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Smadja-Lamère N, Shum M, Déléris P, Roux PP, Abe JI, Marette A. Insulin activates RSK (p90 ribosomal S6 kinase) to trigger a new negative feedback loop that regulates insulin signaling for glucose metabolism. J Biol Chem 2013; 288:31165-76. [PMID: 24036112 DOI: 10.1074/jbc.m113.474148] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We previously demonstrated that the mTORC1/S6K1 pathway is activated by insulin and nutrient overload (e.g. amino acids (AA)), which leads to the inhibition of the PI3K/Akt pathway via the inhibitory serine phosphorylation of IRS-1, notably on serine 1101 (Ser-1101). However, even in the absence of AA, insulin can still promote IRS-1 Ser-1101 phosphorylation by other kinases that remain to be fully characterized. Here, we describe a new negative regulator of IRS-1, the p90 ribosomal S6 kinase (RSK). Computational analyses revealed that Ser-1101 within IRS-1 falls into the consensus motif of RSK. Moreover, recombinant RSK phosphorylated IRS-1 C-terminal fragment on Ser-1101, which was prevented by mutations of this site or when a kinase-inactive mutant of RSK was used. Using antibodies directed toward the phosphorylation sites located in the activation segment of RSK (Ser-221 or Ser-380), we found that insulin activates RSK in L6 myocytes in the absence of AA overload. Inhibition of RSK using either the pharmacological inhibitor BI-D1870 or after adenoviral expression of a dominant negative RSK1 mutant (RSK1-DN) showed that RSK selectively phosphorylates IRS-1 on Ser-1101. Accordingly, expression of the RSK1-DN mutant in L6 myocytes and FAO hepatic cells improved insulin action on glucose uptake and glucose production, respectively. Furthermore, RSK1 inhibition prevented insulin resistance in L6 myocytes chronically exposed to high glucose and high insulin. These results show that RSK is a novel regulator of insulin signaling and glucose metabolism and a potential mediator of insulin resistance, notably through the negative phosphorylation of IRS-1 on Ser-1101.
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Affiliation(s)
- Nicolas Smadja-Lamère
- From the Quebec Heart and Lung Institute, Laval University, 2705 Chemin Ste-Foy, Ste-Foy (Quebec) G1V4G5, Canada
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Lassarre C, Legay C, Karam M, Ricort JM. Platelet-derived growth factor negatively regulates the insulin-like growth factor signaling pathway through the coordinated action of phosphatidylinositol 3-kinase and protein kinase C beta I. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:1367-77. [DOI: 10.1016/j.bbamcr.2013.02.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/07/2013] [Accepted: 02/18/2013] [Indexed: 11/25/2022]
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Dali-Youcef N, Mecili M, Ricci R, Andrès E. Metabolic inflammation: connecting obesity and insulin resistance. Ann Med 2013; 45:242-53. [PMID: 22834949 DOI: 10.3109/07853890.2012.705015] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Insulin resistance is a pathological condition that arises when insulin signaling is impaired, forcing β-cells to produce more insulin in order to cope with body demands and to maintain glucose homeostasis. When the pancreas is no more able to support an appropriate insulin secretion, insulin resistance becomes decompensated and hyperglycemia is detected. One of the mechanisms leading to insulin resistance is low-grade inflammation that involves a number of protagonists such as inflammatory cytokines, lipids and their metabolites, reactive oxygen species (ROS), hypoxia and endoplasmic reticulum stress, and changes in gut microbiota profiles. We review here the molecular aspects of metabolic inflammation converging to insulin resistance and secondarily to type 2 diabetes. We also discuss the place of high-sensitivity C-reactive protein (hsCRP) in the assessment of metabolic inflammation and potential therapeutic interventions aimed to impede inflammation and therefore prevent insulin resistance.
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Affiliation(s)
- Nassim Dali-Youcef
- Laboratoire de Biochimie et de Biologie Moléculaire, Hôpitaux universitaires de Strasbourg, 1 place de l'hôpital 67091 Strasbourg Cedex, France.
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Tassone EJ, Sciacqua A, Andreozzi F, Presta I, Perticone M, Carnevale D, Casaburo M, Hribal ML, Sesti G, Perticone F. Angiotensin (1-7) counteracts the negative effect of angiotensin II on insulin signalling in HUVECs. Cardiovasc Res 2013; 99:129-36. [PMID: 23524303 DOI: 10.1093/cvr/cvt065] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
AIMS Angiotensin II participates to the regulation of cardiovascular physiology and it is involved in molecular mechanisms of insulin resistance. Angiotensin (1-7), derived from angiotensin II metabolism, is able to counteract many of the haemodynamic and non-haemodynamic actions of angiotensin II. In this study, we investigated in human umbilical vein endothelial cells (HUVECs) the possible action of angiotensin (1-7) on the insulin signalling pathway. METHODS AND RESULTS We stimulated HUVECs with insulin, angiotensin II and angiotensin (1-7), testing the effects on endothelial nitric oxide synthase (eNOS) enzyme activation and on insulin receptor substrate-1 (IRS1) phosphorylation. Moreover, we analysed the involvement of angiotensin type1, type2, and Mas receptors in these actions. Finally, we measured the nitric oxide (NO) production, the intracellular cGMP and the PKG-related activity in HUVECs, and the subsequent functional vasoactive effect of angiotensin (1-7) in mesenteric arteries of mice. Angiotensin II inhibits the insulin-induced Akt and eNOS phosphorylation, reducing the NO production. On the other hand, angiotensin (1-7) counteracts the inhibitory effect of angiotensin II, being able to restore the insulin-induced Akt/eNOS activation and the NO production. This effect is mediated by the Mas receptor. The inhibitory effects of angiotensin II on insulin signalling are, at least in part, mediated by an increased serine phosphorylation of IRS₁. Angiotensin (1-7) inhibits the serine phosphorylation of IRS1 induced by angiotensin II. CONCLUSION In endothelial cells angiotensin (1-7) counteracts the negative effects of angiotensin II on insulin signalling and NO production. The balance between angiotensin II and angiotensin (1-7) could represent a key mechanism in the pathophysiological processes leading to endothelial dysfunction and insulin-resistance.
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Affiliation(s)
- Eliezer Joseph Tassone
- Department of Surgical and Medical Sciences, University Magna Græcia of Catanzaro, Campus Universitario di Germaneto, V.le Europa, 88100 Catanzaro, Italy
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Isaac R, Boura-Halfon S, Gurevitch D, Shainskaya A, Levkovitz Y, Zick Y. Selective serotonin reuptake inhibitors (SSRIs) inhibit insulin secretion and action in pancreatic β cells. J Biol Chem 2012; 288:5682-93. [PMID: 23275337 DOI: 10.1074/jbc.m112.408641] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Selective serotonin reuptake inhibitors (SSRIs) are antidepressants used for the treatment of mood and anxiety disorders. Here, we demonstrate that incubation (2 h) of murine islets or Min6 β cell line with the SSRIs paroxetine, fluoxetine, or sertraline inhibited insulin-induced Tyr phosphorylation of insulin receptor substrate (IRS)-2 protein and the activation of its downstream targets Akt and the ribosomal protein S6 kinase-1 (S6K1). Inhibition was dose-dependent with half-maximal effects at ∼15-20 μM. It correlated with a rapid dephosphorylation and activation of the IRS kinase GSK3β. Introduction of GSK3β siRNAs eliminated the inhibitory effects of the SSRIs. Inhibition of IRS-2 action by 30 μM SSRI was associated with a marked inhibition of glucose-stimulated insulin secretion from murine and human pancreatic islets. Secretion induced by basic secretagogues (KCl and Arg) was not affected by these drugs. Prolonged treatment (16 h) of Min6 cells with sertraline resulted in the induction of inducible nitric oxide synthase; activation of endoplasmic reticulum stress, and the initiation of the unfolded protein response, manifested by enhanced transcription of ATF4 and C/EBP homologous protein. This triggered an apoptotic process, manifested by enhanced caspase 3/7 activity, which resulted in β cell death. These findings implicate SSRIs as inhibitors of IRS protein function and insulin action through the activation of GSK3β. They further suggest that SSRIs inhibit insulin secretion; induce the unfolded protein response; activate an apoptotic process, and trigger β cell death. Given that SSRIs promote insulin resistance while inhibiting insulin secretion, these drugs might accelerate the transition from an insulin-resistant state to overt diabetes.
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Affiliation(s)
- Roi Isaac
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100 Israel
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Bhuvaneswari S, Anuradha CV. Astaxanthin prevents loss of insulin signaling and improves glucose metabolism in liver of insulin resistant mice. Can J Physiol Pharmacol 2012. [DOI: 10.1139/y2012-119] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This study investigates the effects of astaxanthin (ASX) on insulin signaling and glucose metabolism in the liver of mice fed a high fat and high fructose diet (HFFD). Adult male Mus musculus mice of body mass 25–30 g were fed either normal chow or the HFFD. After 15 days, mice in each group were subdivided among 2 smaller groups and treated with ASX (2 mg·(kg body mass)–1) in olive oil for 45 days. At the end of 60 days, HFFD-fed mice displayed insulin resistance while ASX-treated HFFD animals showed marked improvement in insulin sensitivity parameters. ASX treatment normalized the activities of hexokinase, pyruvate kinase, glucose-6-phosphatase, fructose-1,6-bisphosphatase, glycogen phosphorylase, and increased glycogen reserves in the liver. Liver tissue from ASX-treated HFFD-fed animals showed increased tyrosine phosphorylation and decreased serine phosphorylation of insulin receptor substrates (IRS)-1 and -2. ASX increased IRS 1/2 and phosphatidylinositol 3-kinase (PI3K) association and serine phosphorylation of Akt. In addition, ASX decreased HFFD-induced serine kinases (c-jun N-terminal kinase-1 and extracellular signal-regulated kinase-1). The results suggest that ASX treatment promotes the IRS–PI3K–Akt pathway of insulin signaling by decreasing serine phosphorylation of IRS proteins, and improves glucose metabolism by modulating metabolic enzymes.
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Affiliation(s)
- Saravanan Bhuvaneswari
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India
| | - Carani Venkatraman Anuradha
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu, India
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Abstract
For many years, the development of insulin resistance has been seen as the core defect responsible for the development of Type 2 diabetes. However, despite extensive research, the initial factors responsible for insulin resistance development have not been elucidated. If insulin resistance can be overcome by enhanced insulin secretion, then hyperglycaemia will never develop. Therefore, a β-cell defect is clearly required for the development of diabetes. There is a wealth of evidence to suggest that disorders in insulin secretion can lead to the development of decreased insulin sensitivity. In this review, we describe the potential initiating defects in Type 2 diabetes, normal pulsatile insulin secretion and the effects that disordered secretion may have on both β-cell function and hepatic insulin sensitivity. We go on to examine evidence from physiological and epidemiological studies describing β-cell dysfunction in the development of insulin resistance. Finally, we describe how disordered insulin secretion may cause intracellular insulin resistance and the implications this concept has for diabetes therapy. In summary, disordered insulin secretion may contribute to development of insulin resistance and hence represent an initiating factor in the progression to Type 2 diabetes.
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Affiliation(s)
- C J Schofield
- Diabetes Centre, Ninewells Hospital and Medical School, Dundee, UK.
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Arunkumar E, Anuradha CV. Genistein promotes insulin action through adenosine monophosphate-activated protein kinase activation and p70 ribosomal protein S6 kinase 1 inhibition in the skeletal muscle of mice fed a high energy diet. Nutr Res 2012; 32:617-25. [PMID: 22935345 DOI: 10.1016/j.nutres.2012.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Revised: 06/02/2012] [Accepted: 06/07/2012] [Indexed: 12/15/2022]
Abstract
Genistein (GEN), a soy isoflavone, exerts insulin-sensitizing actions in animals; however, the underlying mechanisms have not been determined. Because GEN is a known activator of adenosine monophosphate-activated protein kinase (AMPK), we hypothesize that GEN activates insulin signaling through AMPK activation. To test this hypothesis, a high fat-high fructose diet (HFFD)-fed mice model of insulin resistance was administered GEN, and the insulin signaling pathway proteins in the skeletal muscle were examined. Hyperglycemia and hyperinsulinemia observed in HFFD-fed mice were significantly lowered by GEN. GEN increased insulin-stimulated tyrosine phosphorylation of insulin receptor-β and insulin receptor substrate (IRS) 1 but down-regulated IRS-1 serine phosphorylation in the skeletal muscle of HFFD-fed mice. Furthermore, GEN treatment improved muscle IRS-1-associated phospatidylinositol-3 kinase expression, phosphorylation of Akt at Ser(473), and translocation of glucose transporter subtype 4. Phosphorylation of AMPK at Thr(172) and acetyl coenzyme A carboxylase (ACC) at Ser(79) was augmented, whereas phosphorylation of p70 ribosomal protein S6 kinase 1 at Thr(389) was significantly decreased after GEN treatment in the skeletal muscle of HFFD-fed mice. These results suggest that GEN might improve insulin action in the skeletal muscle by targeting AMPK.
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Affiliation(s)
- Elumalai Arunkumar
- Department of Biochemistry and Biotechnology, Annamalai University, Annamalai Nagar, Tamil Nadu, India
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Gao ZG, Ye JP. Why do anti-inflammatory therapies fail to improve insulin sensitivity? Acta Pharmacol Sin 2012; 33:182-8. [PMID: 22036866 PMCID: PMC3270211 DOI: 10.1038/aps.2011.131] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2011] [Accepted: 09/06/2011] [Indexed: 12/25/2022] Open
Abstract
Chronic inflammation occurs in obese conditions in both humans and animals. It also contributes to the pathogenesis of type 2 diabetes (T2D) through insulin resistance, a status in which the body loses its ability to respond to insulin. Inflammation impairs insulin signaling through the functional inhibition of IRS-1 and PPARγ. Insulin sensitizers (such as rosiglitazone and pioglitazone) inhibit inflammation while improving insulin sensitivity. Therefore, anti-inflammatory agents have been suggested as a treatment strategy for insulin resistance. This strategy has been tested in laboratory studies and clinical trials for more than 10 years; however, no significant progress has been made in any of the model systems. This status has led us to re-evaluate the biological significance of chronic inflammation in obesity. Recent studies have consistently asserted that obesity-associated inflammation helps to maintain insulin sensitivity. Inflammation stimulates local adipose tissue remodeling and promotes systemic energy expenditure. We propose that these beneficial activities of inflammation provide an underlying mechanism for the failure of anti-inflammatory therapy in the treatment of insulin resistance. Current literature will be reviewed in this article to present evidence that supports this viewpoint.
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Affiliation(s)
- Zhan-guo Gao
- Antioxidant and Gene Regulation Lab, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
| | - Jian-ping Ye
- Antioxidant and Gene Regulation Lab, Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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Phosphatidylinositol 3-kinase and protein kinase D1 specifically cooperate to negatively regulate the insulin-like growth factor signaling pathway. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:558-69. [DOI: 10.1016/j.bbamcr.2011.12.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Revised: 11/28/2011] [Accepted: 12/20/2011] [Indexed: 11/20/2022]
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