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DeVallance E, Branyan KW, Lemaster K, Olfert IM, Smith DM, Pistilli EE, Frisbee JC, Chantler PD. Aortic dysfunction in metabolic syndrome mediated by perivascular adipose tissue TNFα- and NOX2-dependent pathway. Exp Physiol 2018; 103:590-603. [PMID: 29349831 DOI: 10.1113/ep086818] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/15/2018] [Indexed: 12/17/2022]
Abstract
NEW FINDINGS What is the central question of this study? Tumour necrosis factor-α (TNFα) has been shown to impair vascular function, but the impact of thoracic aorta perivascular adipose tissue (tPVAT)-derived TNFα on tPVAT and aortic function in metabolic syndrome is unknown. What is the main finding and its importance? Release of TNFα by tPVAT causes production of reactive oxygen species in tPVAT through activation of an NADPH-oxidase 2 (NOX2)-dependent pathway, activates production of aortic reactive oxygen species and mediates aortic stiffness, potentially through matrix metalloproteinase 9 activity. Neutralization of TNFα and/or inhibition of NOX2 blocks the tPVAT-induced impairment of aortic function. These data partly implicate tPVAT NOX2 and TNFα in mediating the vascular pathology of metabolic syndrome. ABSTRACT Perivascular adipose tissue (PVAT) is recognized for its vasoactive effects, but it is unclear how metabolic syndrome impacts thoracic aorta (t)PVAT and the subsequent effect on functional and structural aortic stiffness. Thoracic aorta and tPVAT were removed from 16- to 17-week-old lean (LZR, n = 16) and obese Zucker rats (OZR, n = 16). The OZR presented with aortic endothelial dysfunction, assessed by wire myography, and increased aortic stiffness, assessed by elastic modulus. The OZR tPVAT exudate further exacerbated the endothelial dysfunction, reducing nitric oxide and endothelium-dependent relaxation (P < 0.05). Additionally, OZR tPVAT exudate had increased MMP9 activity (P < 0.05) and further increased the elastic modulus of the aorta after 72 h of co-culture (P < 0.05). We found that the observed aortic dysfunction caused by OZR tPVAT was mediated through increased production and release of tumour necrosis factor-α (TNFα; P < 0.01), which was dependent on tPVAT NADPH-oxidase 2 (NOX2) activity. The OZR tPVAT release of reactive oxygen species and subsequent aortic dysfunction were inhibited by TNFα neutralization and/or inhibition of NOX2. Additionally, we found that OZR tPVAT had reduced activity of the active sites of the 20S proteasome (P < 0.05) and reduced superoxide dismutase activity (P < 0.01). In conclusion, metabolic syndrome causes tPVAT dysfunction through an interplay between TNFα and NOX2 that leads to tPVAT-mediated aortic stiffness by activation of aortic reactive oxygen species and increased MMP9 activity.
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Affiliation(s)
- Evan DeVallance
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Kayla W Branyan
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Kent Lemaster
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - I Mark Olfert
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - David M Smith
- Department of Biochemistry, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Emidio E Pistilli
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
| | - Jefferson C Frisbee
- Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada.,Department of Medical Biophysics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada
| | - Paul D Chantler
- Division of Exercise Physiology, West Virginia University School of Medicine, Morgantown, WV, USA
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High-Fructose Consumption Impairs the Redox System and Protein Quality Control in the Brain of Syrian Hamsters: Therapeutic Effects of Melatonin. Mol Neurobiol 2018; 55:7973-7986. [DOI: 10.1007/s12035-018-0967-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 02/16/2018] [Indexed: 02/06/2023]
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Ho N, Xu C, Thibault G. From the unfolded protein response to metabolic diseases - lipids under the spotlight. J Cell Sci 2018; 131:131/3/jcs199307. [PMID: 29439157 DOI: 10.1242/jcs.199307] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The unfolded protein response (UPR) is classically viewed as a stress response pathway to maintain protein homeostasis at the endoplasmic reticulum (ER). However, it has recently emerged that the UPR can be directly activated by lipid perturbation, independently of misfolded proteins. Comprising primarily phospholipids, sphingolipids and sterols, individual membranes can contain hundreds of distinct lipids. Even with such complexity, lipid distribution in a cell is tightly regulated by mechanisms that remain incompletely understood. It is therefore unsurprising that lipid dysregulation can be a key factor in disease development. Recent advances in analysis of lipids and their regulators have revealed remarkable mechanisms and connections to other cellular pathways including the UPR. In this Review, we summarize the current understanding in UPR transducers functioning as lipid sensors and the interplay between lipid metabolism and ER homeostasis in the context of metabolic diseases. We attempt to provide a framework consisting of a few key principles to integrate the different lines of evidence and explain this rather complicated mechanism.
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Affiliation(s)
- Nurulain Ho
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
| | - Chengchao Xu
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142-1479, USA
| | - Guillaume Thibault
- School of Biological Sciences, Nanyang Technological University, Singapore, 637551
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Rutkowski DT. Liver function and dysfunction - a unique window into the physiological reach of ER stress and the unfolded protein response. FEBS J 2018; 286:356-378. [PMID: 29360258 DOI: 10.1111/febs.14389] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 01/08/2018] [Accepted: 01/17/2018] [Indexed: 02/06/2023]
Abstract
The unfolded protein response (UPR) improves endoplasmic reticulum (ER) protein folding in order to alleviate stress. Yet it is becoming increasingly clear that the UPR regulates processes well beyond those directly involved in protein folding, in some cases by mechanisms that fall outside the realm of canonical UPR signaling. These pathways are highly specific from one cell type to another, implying that ER stress signaling affects each tissue in a unique way. Perhaps nowhere is this more evident than in the liver, which-beyond being a highly secretory tissue-is a key regulator of peripheral metabolism and a uniquely proliferative organ upon damage. The liver provides a powerful model system for exploring how and why the UPR extends its reach into physiological processes that occur outside the ER, and how ER stress contributes to the many systemic diseases that involve liver dysfunction. This review will highlight the ways in which the study of ER stress in the liver has expanded the view of the UPR to a response that is a key guardian of cellular homeostasis outside of just the narrow realm of ER protein folding.
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Affiliation(s)
- D Thomas Rutkowski
- Department of Anatomy and Cell Biology, University of Iowa Carver College of Medicine, IA, USA.,Department of Internal Medicine, University of Iowa Carver College of Medicine, IA, USA
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Obrosov A, Coppey LJ, Shevalye H, Yorek MA. Effect of Fish Oil vs. Resolvin D1, E1, Methyl Esters of Resolvins D1 or D2 on Diabetic Peripheral Neuropathy. ACTA ACUST UNITED AC 2017; 8. [PMID: 29423332 PMCID: PMC5800519 DOI: 10.4172/2155-9562.1000453] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Objective Fish oil is enriched in omega-3 polyunsaturated fatty acids primarily eicosapentaenoic and docosahexaenoic fatty acids. Metabolites of these two polyunsaturated fatty acids include the E and D series resolvins. Omega-3 polyunsaturated fatty acids and resolvins have been reported to have anti-inflammatory and neuroprotective properties. The objective of this study was to evaluate the efficacy of menhaden oil, a fish oil derived from the menhaden, resolvins D1 and E1 and the methyl esters of resolvins D1 and D2 on diabetic peripheral neuropathy. Hypothesis being examined was that the methyl esters of resolvins D1 and D2 would be move efficacious than resolvins D1 or E1 due to an extended half-life. Methods A model of type 2 diabetes in C57BL/6J mice was created through a combination of a high fat diet followed 8 weeks later with treatment of low dosage of streptozotocin. After 8 weeks of untreated hyperglycemia type 2 diabetic mice were treated for 8 weeks with menhaden oil in the diet or daily injections of 1 ng/g body weight resolvins D1, E1 or methyl esters of resolvins D1 or D2. Afterwards, multiple neurological endpoints were examined. Results Menhaden oil or resolvins did not improve hyperglycemia. Untreated diabetic mice were thermal hypoalgesic, had mechanical allodynia, reduced motor and sensory nerve conduction velocities and decreased innervation of the cornea and skin. These endpoints were significantly improved with menhaden oil or resolvin treatment. However, the methyl esters of resolvins D1 or D2, contrary to our hypothesis, were generally less potent than menhaden oil or resolvins D1 or E1. Conclusion These studies further support omega-3 polyunsaturated fatty acids derived from fish oil via in part due to their metabolites could be an effective treatment for diabetic neuropathy.
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Affiliation(s)
| | | | - Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, USA
| | - Mark A Yorek
- Department of Internal Medicine, University of Iowa, Iowa City, USA.,Department of Veterans Affairs, Iowa City Health Care System, Iowa City, USA.,Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, USA.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, USA
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Schafer MJ, Miller JD, LeBrasseur NK. Cellular senescence: Implications for metabolic disease. Mol Cell Endocrinol 2017; 455:93-102. [PMID: 27591120 PMCID: PMC5857952 DOI: 10.1016/j.mce.2016.08.047] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 08/03/2016] [Accepted: 08/29/2016] [Indexed: 12/19/2022]
Abstract
The growing burden of obesity- and aging-related diseases has hastened the search for governing biological processes. Cellular senescence is a stress-induced state of stable growth arrest strongly associated with aging that is aberrantly activated by obesity. The transition of a cell to a senescent state is demarcated by an array of phenotypic markers, and leveraging their context-dependent presentation is essential for determining the influence of senescent cells on tissue pathogenesis. Biomarkers of senescent cells have been identified in tissues that contribute to metabolic disease, including fat, liver, skeletal muscle, pancreata, and cardiovascular tissue, suggesting that pharmacological and behavioral interventions that alter their abundance and/or behavior may be a novel therapeutic strategy. However, contradictory findings with regard to a protective versus deleterious role of senescent cells in certain contexts emphasize the need for additional studies to uncover the complex interplay that defines multi-organ disease processes associated with obesity and aging.
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Affiliation(s)
- Marissa J Schafer
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA; Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, 55905, USA
| | - Jordan D Miller
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA; Department of Surgery, Mayo Clinic, Rochester, MN, 55905, USA; Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55905, USA
| | - Nathan K LeBrasseur
- Robert and Arlene Kogod Center on Aging, Mayo Clinic, Rochester, MN, 55905, USA; Department of Physical Medicine and Rehabilitation, Mayo Clinic, Rochester, MN, 55905, USA.
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Rodriguez Camargo DC, Tripsianes K, Buday K, Franko A, Göbl C, Hartlmüller C, Sarkar R, Aichler M, Mettenleiter G, Schulz M, Böddrich A, Erck C, Martens H, Walch AK, Madl T, Wanker EE, Conrad M, de Angelis MH, Reif B. The redox environment triggers conformational changes and aggregation of hIAPP in Type II Diabetes. Sci Rep 2017; 7:44041. [PMID: 28287098 PMCID: PMC5347123 DOI: 10.1038/srep44041] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Accepted: 02/03/2017] [Indexed: 12/22/2022] Open
Abstract
Type II diabetes (T2D) is characterized by diminished insulin production and resistance of cells to insulin. Among others, endoplasmic reticulum (ER) stress is a principal factor contributing to T2D and induces a shift towards a more reducing cellular environment. At the same time, peripheral insulin resistance triggers the over-production of regulatory hormones such as insulin and human islet amyloid polypeptide (hIAPP). We show that the differential aggregation of reduced and oxidized hIAPP assists to maintain the redox equilibrium by restoring redox equivalents. Aggregation thus induces redox balancing which can assist initially to counteract ER stress. Failure of the protein degradation machinery might finally result in β-cell disruption and cell death. We further present a structural characterization of hIAPP in solution, demonstrating that the N-terminus of the oxidized peptide has a high propensity to form an α-helical structure which is lacking in the reduced state of hIAPP. In healthy cells, this residual structure prevents the conversion into amyloidogenic aggregates.
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Affiliation(s)
- Diana C Rodriguez Camargo
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Konstantinos Tripsianes
- Central European Institute of Technology (CEITEC), Masaryk University, Kamenice 5, Brno 62500, Czech Republic
| | - Katalin Buday
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Andras Franko
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg 85764, Germany
| | - Christoph Göbl
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Christoph Hartlmüller
- Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Riddhiman Sarkar
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
| | - Michaela Aichler
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | | | - Michael Schulz
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Annett Böddrich
- Max-Delbrück-Center Berlin (MDC), Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Christian Erck
- Synaptic Systems GmbH, Rudolf-Wissell-Straße 28, Göttingen, 37079, Germany
| | - Henrik Martens
- Synaptic Systems GmbH, Rudolf-Wissell-Straße 28, Göttingen, 37079, Germany
| | - Axel Karl Walch
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Tobias Madl
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany.,Institute of Molecular Biology &Biochemistry, Center of Molecular Medicine, Medical University of Graz, Austria
| | - Erich E Wanker
- Max-Delbrück-Center Berlin (MDC), Robert-Rössle-Str. 10, Berlin 13125, Germany
| | - Marcus Conrad
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany
| | - Martin Hrabě de Angelis
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg 85764, Germany.,Technische Universität München, Center of Life and Food Sciences Weihenstephan, Freising 85354, Germany
| | - Bernd Reif
- Helmholtz Zentrum München, Ingolstädter Landstr. 1, Neuherberg 85764, Germany.,Munich Center for Integrated Protein Science (CIPS-M) at Department Chemie, Technische Universität München (TUM), Germany
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PA28 modulates antigen processing and viral replication during coxsackievirus B3 infection. PLoS One 2017; 12:e0173259. [PMID: 28278207 PMCID: PMC5344377 DOI: 10.1371/journal.pone.0173259] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 02/17/2017] [Indexed: 11/19/2022] Open
Abstract
The function of the proteasome is modulated at the level of subunit expression and by association with its regulatory complexes. During coxsackievirus B3 (CVB3) myocarditis, IFN-induced formation of immunoproteasomes (ip) is known to be critical for regulating immune modulating molecules. The function of the IFN-γ-inducible proteasome regulator subunits PA28 α and β, however, in this context was unknown. During viral myocarditis, we found an increased abundance of PA28β subunits in heart tissue. PA28α/β exists in PA28-20S-PA28 and PA700-20S-PA28 hybrid proteasome complexes in cells both with either predominant ip and standard proteasome (sp) expression. Being in line with reduced proteasome activity in PA28α/β-deficient cells, we observed increased levels of oxidized and poly-ubiquitinated proteins upon TLR3-activation in these cells. Moreover, PA28α/β is capable to interfere directly with viral replication of CVB3 and facilitates the generation of CVB3-derived MHC class I epitopes by the proteasome. In contrast to a distinct function of PA28α/β in vitro, gene ablation of PA28α/β in mice being on a genetic background with resistance towards the development of severe infection had no significant impact on disease progression. Other than reported for the ip, in this host PA28α/β is dispensable to meet the demand of increased peptide hydrolysis capacity by the proteasome during viral myocarditis.
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The Pathogenesis of Obesity-Associated Adipose Tissue Inflammation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 960:221-245. [DOI: 10.1007/978-3-319-48382-5_9] [Citation(s) in RCA: 144] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Tanaka S, Hikita H, Tatsumi T, Sakamori R, Nozaki Y, Sakane S, Shiode Y, Nakabori T, Saito Y, Hiramatsu N, Tabata K, Kawabata T, Hamasaki M, Eguchi H, Nagano H, Yoshimori T, Takehara T. Rubicon inhibits autophagy and accelerates hepatocyte apoptosis and lipid accumulation in nonalcoholic fatty liver disease in mice. Hepatology 2016; 64:1994-2014. [PMID: 27637015 DOI: 10.1002/hep.28820] [Citation(s) in RCA: 244] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 08/13/2016] [Indexed: 12/11/2022]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide. It encompasses a spectrum ranging from simple steatosis to fatty liver with hepatocellular injury, termed nonalcoholic steatohepatitis. Recent studies have demonstrated hepatic autophagy being impaired in NAFLD. In the present study, we investigated the impact of Rubicon, a Beclin1-interacting negative regulator for autophagosome-lysosome fusion, in the pathogenesis of NAFLD. In HepG2 cells, BNL-CL2 cells, and murine primary hepatocytes, Rubicon was posttranscriptionally up-regulated by supplementation with saturated fatty acid palmitate. Up-regulation of Rubicon was associated with suppression of the late stage of autophagy, as evidenced by accumulation of both LC3-II and p62 expression levels as well as decreased autophagy flux. Its blockade by small interfering RNA attenuated autophagy impairment and reduced palmitate-induced endoplasmic reticulum stress, apoptosis, and lipid accumulation. Rubicon was also up-regulated in association with autophagy impairment in livers of mice fed a high-fat diet (HFD). Hepatocyte-specific Rubicon knockout mice generated by crossing Rubicon floxed mice with albumin-Cre transgenic mice did not produce any phenotypes on a normal diet. In contrast, on an HFD, they displayed significant improvement of both liver steatosis and injury as well as attenuation of both endoplasmic reticulum stress and autophagy impairment in the liver. In humans, liver tissues obtained from patients with NAFLD expressed significantly higher levels of Rubicon than those without steatosis. CONCLUSION Rubicon is overexpressed and plays a pathogenic role in NAFLD by accelerating hepatocellular lipoapoptosis and lipid accumulation, as well as inhibiting autophagy. Rubicon may be a novel therapeutic target for regulating NAFLD development and progression. (Hepatology 2016;64:1994-2014).
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Affiliation(s)
- Satoshi Tanaka
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hayato Hikita
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tomohide Tatsumi
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ryotaro Sakamori
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yasutoshi Nozaki
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Sadatsugu Sakane
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yuto Shiode
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tasuku Nakabori
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshinobu Saito
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Naoki Hiramatsu
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Keisuke Tabata
- Department of Genetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tsuyoshi Kawabata
- Department of Genetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Maho Hamasaki
- Department of Genetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hidetoshi Eguchi
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hiroaki Nagano
- Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tamotsu Yoshimori
- Department of Genetics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tetsuo Takehara
- Department of Gastroenterology and Hepatology, Osaka University Graduate School of Medicine, Osaka, Japan
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Takatori O, Usui S, Okajima M, Kaneko S, Ootsuji H, Takashima SI, Kobayashi D, Murai H, Furusho H, Takamura M. Sodium 4-Phenylbutyrate Attenuates Myocardial Reperfusion Injury by Reducing the Unfolded Protein Response. J Cardiovasc Pharmacol Ther 2016; 22:283-292. [PMID: 27909014 DOI: 10.1177/1074248416679308] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND The unfolded protein response (UPR) plays a pivotal role in ischemia-reperfusion (I/R) injury in various organs such as heart, brain, and liver. Sodium 4-phenylbutyrate (PBA) reportedly acts as a chemical chaperone that reduces UPR. In the present study, we evaluated the effect of PBA on reducing the UPR and protecting against myocardial I/R injury in mice. METHODS Male C57BL/6 mice were subjected to 30-minute myocardial I/R, and were treated with phosphate-buffered saline (as a vehicle) or PBA. RESULTS At 4 hours after reperfusion, mice treated with PBA had reduced serum cardiac troponin I levels and numbers of apoptotic cells in left ventricles (LVs) in myocardial I/R. Infarct size had also reduced in mice treated with PBA at 48 hours after reperfusion. At 2 hours after reperfusion, UPR markers, including eukaryotic initiation of the factor 2α-subunit, activating transcription factor-6, inositol-requiring enzyme-1, glucose-regulated protein 78, CCAAT/enhancer-binding protein (C/EBP) homologous protein, and caspase-12, were significantly increased in mice treated with vehicle compared to sham-operated mice. Administration of PBA significantly reduced the I/R-induced increases of these markers. Cardiac function and dimensions were assessed at 21 days after I/R. Sodium 4-phenylbutyrate dedicated to the improvement of cardiac parameters deterioration including LV end-diastolic diameter and LV fractional shortening. Consistently, PBA reduced messenger RNA expression levels of cardiac remodeling markers such as collagen type 1α1, brain natriuretic peptide, and α skeletal muscle actin in LV at 21 days after I/R. CONCLUSION Unfolded protein response mediates myocardial I/R injury. Administration of PBA reduces the UPR, apoptosis, infarct size, and preserved cardiac function. Hence, PBA may be a therapeutic option to attenuate myocardial I/R injury in clinical practice.
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Affiliation(s)
- Osamu Takatori
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Soichiro Usui
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masaki Okajima
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Shuichi Kaneko
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Hiroshi Ootsuji
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Shin-Ichiro Takashima
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Daisuke Kobayashi
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Hisayoshi Murai
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Hiroshi Furusho
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
| | - Masayuki Takamura
- 1 Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Science, Kanazawa, Japan
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Minard AY, Wong MKL, Chaudhuri R, Tan SX, Humphrey SJ, Parker BL, Yang JY, Laybutt DR, Cooney GJ, Coster ACF, Stöckli J, James DE. Hyperactivation of the Insulin Signaling Pathway Improves Intracellular Proteostasis by Coordinately Up-regulating the Proteostatic Machinery in Adipocytes. J Biol Chem 2016; 291:25629-25640. [PMID: 27738101 DOI: 10.1074/jbc.m116.741140] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 10/11/2016] [Indexed: 01/25/2023] Open
Abstract
Hyperinsulinemia, which is associated with aging and metabolic disease, may lead to defective protein homeostasis (proteostasis) due to hyperactivation of insulin-sensitive pathways such as protein synthesis. We investigated the effect of chronic hyperinsulinemia on proteostasis by generating a time-resolved map of insulin-regulated protein turnover in adipocytes using metabolic pulse-chase labeling and high resolution mass spectrometry. Hyperinsulinemia increased the synthesis of nearly half of all detected proteins and did not affect protein degradation despite suppressing autophagy. Unexpectedly, this marked elevation in protein synthesis was accompanied by enhanced protein stability and folding and not by markers of proteostasis stress such as protein carbonylation and aggregation. The improvement in proteostasis was attributed to a coordinate up-regulation of proteins in the global proteostasis network, including ribosomal, proteasomal, chaperone, and endoplasmic reticulum/mitochondrial unfolded protein response proteins. We conclude that defects associated with hyperactivation of the insulin signaling pathway are unlikely attributed to defective proteostasis because up-regulation of protein synthesis by insulin is accompanied by up-regulation of proteostatic machinery.
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Affiliation(s)
- Annabel Y Minard
- From The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia.,Charles Perkins Centre, School of Life Environmental Sciences
| | - Martin K L Wong
- From The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia.,Charles Perkins Centre, School of Life Environmental Sciences.,School of Physics
| | - Rima Chaudhuri
- Charles Perkins Centre, School of Life Environmental Sciences
| | - Shi-Xiong Tan
- From The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia
| | - Sean J Humphrey
- Charles Perkins Centre, School of Life Environmental Sciences
| | | | | | - D Ross Laybutt
- From The Garvan Institute of Medical Research, Sydney, New South Wales 2010, Australia
| | | | - Adelle C F Coster
- Department of Applied Mathematics, School of Mathematics and Statistics, University of New South Wales, Sydney, New South Wales 2052, Australia
| | | | - David E James
- Charles Perkins Centre, School of Life Environmental Sciences, .,School of Medicine, University of Sydney, Sydney, New South Wales 2006, Australia, and
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64
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Pagliassotti MJ, Kim PY, Estrada AL, Stewart CM, Gentile CL. Endoplasmic reticulum stress in obesity and obesity-related disorders: An expanded view. Metabolism 2016; 65:1238-46. [PMID: 27506731 PMCID: PMC4980576 DOI: 10.1016/j.metabol.2016.05.002] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Revised: 04/01/2016] [Accepted: 05/06/2016] [Indexed: 02/07/2023]
Abstract
The endoplasmic reticulum (ER) is most notable for its central roles in calcium ion storage, lipid biosynthesis, and protein sorting and processing. By virtue of its extensive membrane contact sites that connect the ER to most other organelles and to the plasma membrane, the ER can also regulate diverse cellular processes including inflammatory and insulin signaling, nutrient metabolism, and cell proliferation and death via a signaling pathway called the unfolded protein response (UPR). Chronic UPR activation has been observed in liver and/or adipose tissue of dietary and genetic murine models of obesity, and in human obesity and non-alcoholic fatty liver disease (NAFLD). Activation of the UPR in obesity and obesity-related disorders likely has two origins. One linked to classic ER stress involving the ER lumen and one linked to alterations to the ER membrane environment. This review discusses both of these origins and also considers the role of post-translational protein modifications, such as acetylation and palmitoylation, and ER-mitochondrial interactions to obesity-mediated impairments in the ER and activation of the UPR.
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Affiliation(s)
| | - Paul Y Kim
- Department of Biological Sciences, Grambling State University
| | - Andrea L Estrada
- Department of Food Science and Human Nutrition, Colorado State University
| | - Claire M Stewart
- Department of Food Science and Human Nutrition, Colorado State University
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65
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Amelioration of neuronal cell death in a spontaneous obese rat model by dietary restriction through modulation of ubiquitin proteasome system. J Nutr Biochem 2016; 33:73-81. [DOI: 10.1016/j.jnutbio.2016.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/02/2016] [Accepted: 03/07/2016] [Indexed: 01/11/2023]
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66
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Nitric oxide differentially affects proteasome activator 28 after arterial injury in type 1 and type 2 diabetic rats. J Surg Res 2016; 202:413-21. [PMID: 27229117 DOI: 10.1016/j.jss.2016.01.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 11/20/2022]
Abstract
BACKGROUND Diabetic patients display aggressive restenosis after vascular interventions, likely because of proproliferative influences of hyperglycemia and hyperinsulinemia. We have shown that nitric oxide (NO) inhibits neointimal hyperplasia in type 2, but not in type 1, diabetic rats. Here, we examined proteasome activator 28 (PA28) after arterial injury in different diabetic environments, with or without NO. We hypothesize that NO differentially affects PA28 levels based on metabolic environment. MATERIALS AND METHODS Vascular smooth muscle cell (VSMC) lysates from male, nondiabetic Lean Zucker (LZ) and Zucker Diabetic Fatty (ZDF) rats were assayed for 26S proteasome activity with or without PA28 and S-nitroso-N-acetylpenicillamine. LZ and ZDF VSMCs were treated with (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate for 24 h. Balloon-injured carotid arteries from LZ, streptozotocin-injected LZ (STZ, type 1), and ZDF (type 2) rats treated with disodium 1-[2-(carboxylato)pyrrolidin-1-iyl]diazen-1-ium-1,2-diolate were harvested at 3 or 14 d. PA28α was assessed by Western blotting and immunofluorescent staining. RESULTS S-nitroso-N-acetylpenicillamine reversed PA28-stimulated increases in 26S proteasome activity in LZ and ZDF VSMCs. Increased (Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate lowered PA28α in LZ VSMCs but increased PA28α in ZDF VSMCs. At 3 d after injury, disodium 1-[2-(carboxylato)pyrrolidin-1-iyl]diazen-1-ium-1,2-diolate potentiated injury-induced PA28α decreases in LZ, STZ, and ZDF rats, suggesting VSMCs, depleted at this early time point, are major sources of PA28α. At 14 d after injury, total PA28α staining returned to baseline. However, although intimal and medial PA28α staining increased in injured STZ rats, adventitial PA28α staining increased in injured ZDF rats. CONCLUSIONS PA28 dysregulation may explain the differential ability of NO to inhibit neointimal hyperplasia in type 1 versus type 2 diabetes.
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67
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Miyagawa K, Oe S, Honma Y, Izumi H, Baba R, Harada M. Lipid-Induced Endoplasmic Reticulum Stress Impairs Selective Autophagy at the Step of Autophagosome-Lysosome Fusion in Hepatocytes. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:1861-1873. [PMID: 27157992 DOI: 10.1016/j.ajpath.2016.03.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/18/2016] [Accepted: 03/04/2016] [Indexed: 02/08/2023]
Abstract
Blockage of hepatic autophagic degradation system occurs in obesity and is associated with the development of nonalcoholic fatty liver disease. However, the mechanism of this blockage remains unclear. We found a high-fat diet induced accumulation of autophagosomes in the mice livers. However, autophagy substrates such as p62 and ubiquitinated proteins also accumulated in the livers in this model. These findings indicate the possibility that a high-fat diet impairs autophagic flux in the liver. Then, to assess the autophagic flux in more detail, we performed analyses of autophagic flux in cultured hepatocytes exposed to monounsaturated fatty acids (FAs) or saturated FAs (SFAs). SFAs but not monounsaturated FAs suppressed degradation of contents in the autophagosomes. We analyzed each stage of the autophagy pathway (ie, autophagosome formation, autophagosome-lysosome fusion, lysosomal degradation) in cultured hepatocytes treated with monounsaturated FAs or SFAs and found that SFAs impaired autophagosome-lysosome fusion. This impairment occurred in an endoplasmic reticulum stress-dependent manner. Moreover, ubiquitin and p62-positive inclusions observed in high-fat diet-fed mice livers and SFA-treated cells were sequestered within autophagosomes. We also found that SFA-induced accumulation of Ser351-phosphorylated p62, which is indispensable for selective autophagy, further increased on administration of a lysosomal proteinase inhibitor. Although lipid-induced endoplasmic reticulum stress interferes with the autophagosome-lysosome fusion, selective autophagic sequestration of aggregated proteins is not inhibited.
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Affiliation(s)
- Koichiro Miyagawa
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
| | - Shinji Oe
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Yuichi Honma
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Hiroto Izumi
- Department of Occupational Pneumology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Ryoko Baba
- Department of Anatomy, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Masaru Harada
- Third Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
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68
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Shen J, Tsoi H, Liang Q, Chu ESH, Liu D, Yu ACS, Chan TF, Li X, Sung JJY, Wong VWS, Yu J. Oncogenic mutations and dysregulated pathways in obesity-associated hepatocellular carcinoma. Oncogene 2016; 35:6271-6280. [PMID: 27132506 PMCID: PMC5153568 DOI: 10.1038/onc.2016.162] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 04/01/2016] [Accepted: 04/03/2016] [Indexed: 02/07/2023]
Abstract
Epidemiological studies showed that obesity and its related non-alcoholic fatty liver disease (NAFLD) promote hepatocellular carcinoma (HCC) development. We aimed to uncover the genetic alterations of NAFLD-HCC using whole-exome sequencing. We compared HCC development in genetically obese mice and dietary obese mice with wild-type lean mice fed a normal chow after treatment with diethylnitrosamine. HCC tumor and adjacent normal samples from obese and lean mice were then subjected to whole-exome sequencing. Functional and mechanistic importance of the identified mutations in Carboxyl ester lipase (Cel) gene and Harvey rat sarcoma virus oncogene 1 (Hras) was further elucidated. We demonstrated significantly higher incidences of HCC in both genetic and dietary obese mice with NAFLD development as compared with lean mice without NAFLD. The mutational signatures of NAFLD-HCC and lean HCC were distinct, with <3% overlapped. Eight metabolic or oncogenic pathways were found to be significantly enriched by mutated genes in NAFLD-HCC, but only two of these pathways were dysregulated by mutations in lean HCC. In particular, Cel was mutated significantly more frequently in NAFLD-HCC than in lean HCC. The multiple-site mutations in Cel are loss-of-function mutations, with effects similar to Cel knock-down. Mutant Cel caused accumulation of cholesteryl ester in liver cells, which led to induction of endoplasmic reticulum stress and consequently activated the IRE1α/c-Jun N-terminal kinase (JNK)/c-Jun/activating protein-1 (AP-1) signaling cascade to promote liver cell growth. In addition, single-site mutations in Hras at codon 61 were found in NAFLD-HCC but none in lean HCC. The gain-of-function mutations in Hras (Q61R and Q61K) significantly promoted liver cell growth through activating the mitogen-activated protein kinase (MAPK) and phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K)/3-phosphoinositide-dependent protein kinase-1 (PDK1)/Akt pathways. In conclusion, we have identified mutation signature and pathways in NAFLD-associated HCC. Mutations in Cel and Hras have important roles in NAFLD-associated hepatocellular carcinogenesis.
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Affiliation(s)
- J Shen
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - H Tsoi
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - Q Liang
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - E S H Chu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - D Liu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - A C-S Yu
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - T F Chan
- School of Life Sciences, and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
| | - X Li
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - J J Y Sung
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - V W S Wong
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
| | - J Yu
- Institute of Digestive Disease and Department of Medicine and Therapeutics, State Key Laboratory of Digestive Disease, Li Ka Shing Institute of Health Sciences, CUHK Shenzhen Research Institute, The Chinese University of Hong Kong, Hong Kong, China
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69
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Kwak HJ, Choi HE, Jang J, Park SK, Bae YA, Cheon HG. Bortezomib attenuates palmitic acid-induced ER stress, inflammation and insulin resistance in myotubes via AMPK dependent mechanism. Cell Signal 2016; 28:788-97. [PMID: 27049873 DOI: 10.1016/j.cellsig.2016.03.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 03/24/2016] [Accepted: 03/28/2016] [Indexed: 11/30/2022]
Abstract
Bortezomib is an anti-cancer agent that induces ER stress by inhibiting proteasomal degradation. However, the effects of bortezomib appear to be dependent on its concentration and cellular context. Since ER stress is closely related to type 2 diabetes, the authors examined the effects of bortezomib on palmitic acid (PA)-induced ER stress in C2C12 murine myotubes. At low concentrations (<20nM), bortezomib protected myotubes from PA (750μM)-induced ER stress and inflammation. Either tunicamycin or thapsigargin-induced ER stress was also reduced by bortezomib. In addition, reduced glucose uptake and Akt phosphorylation induced by PA were prevented by co-treating bortezomib (10nM) both in the presence or absence of insulin. These protective effects of bortezomib were found to be associated with reduced JNK phosphorylation. Furthermore, bortezomib-induced AMPK phosphorylation, and the protective effects of bortezomib were diminished by AMPK knockdown, suggesting that AMPK activation underlies the effects of bortezomib. The in vivo administration of bortezomib at nontoxic levels (at 50 or 200μg/kg, i.p.) twice weekly for 5weeks to ob/ob mice improved insulin resistance, increased AMPK phosphorylation, reduced ER stress marker levels, and JNK inhibition in skeletal muscle. The study shows that bortezomib reduces ER stress, inflammation, and insulin resistance in vitro and in vivo, and suggests that bortezomib has novel applications for the treatment of metabolic disorders.
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Affiliation(s)
- Hyun Jeong Kwak
- Department of Pharmacology, Gachon University School of Medicine, Incheon 406-799, Republic of Korea
| | - Hye-Eun Choi
- Department of Pharmacology, Gachon University School of Medicine, Incheon 406-799, Republic of Korea
| | - Jinsun Jang
- Department of Pharmacology, Gachon University School of Medicine, Incheon 406-799, Republic of Korea
| | - Soo Kyung Park
- Department of Pharmacology, Gachon University School of Medicine, Incheon 406-799, Republic of Korea
| | - Young-An Bae
- Department of Microbiology, Gachon University, Incheon 406-799, Republic of Korea
| | - Hyae Gyeong Cheon
- Department of Pharmacology, Gachon University School of Medicine, Incheon 406-799, Republic of Korea; Gachon Medical Research Institute, Gil Medical Center, Incheon 405-760, Republic of Korea.
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70
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Proteasome activators, PA28γ and PA200, play indispensable roles in male fertility. Sci Rep 2016; 6:23171. [PMID: 27003159 PMCID: PMC4802386 DOI: 10.1038/srep23171] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 02/25/2016] [Indexed: 01/26/2023] Open
Abstract
Protein degradation mediated by the proteasome is important for the protein homeostasis. Various proteasome activators, such as PA28 and PA200, regulate the proteasome function. Here we show double knockout (dKO) mice of Psme3 and Psme4 (genes for PA28γ and PA200), but not each single knockout mice, are completely infertile in male. The dKO sperms exhibited remarkable defects in motility, although most of them showed normal appearance in morphology. The proteasome activity of the mutant sperms decreased notably, and the sperms were strongly positive with ubiquitin staining. Quantitative analyses of proteins expressed in dKO sperms revealed up-regulation of several proteins involved in oxidative stress response. Furthermore, increased 8-OHdG staining was observed in dKO sperms head, suggesting defective response to oxidative damage. This report verified PA28γ and PA200 play indispensable roles in male fertility, and provides a novel insight into the role of proteasome activators in antioxidant response.
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71
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Tekola-Ayele F, Doumatey AP, Shriner D, Bentley AR, Chen G, Zhou J, Fasanmade O, Johnson T, Oli J, Okafor G, Eghan BA, Agyenim-Boateng K, Adebamowo C, Amoah A, Acheampong J, Adeyemo A, Rotimi CN. Genome-wide association study identifies African-ancestry specific variants for metabolic syndrome. Mol Genet Metab 2015; 116:305-13. [PMID: 26507551 PMCID: PMC5292212 DOI: 10.1016/j.ymgme.2015.10.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Revised: 10/21/2015] [Accepted: 10/21/2015] [Indexed: 12/21/2022]
Abstract
The metabolic syndrome (MetS) is a constellation of metabolic disorders that increase the risk of developing several diseases including type 2 diabetes and cardiovascular diseases. Although genome-wide association studies (GWAS) have successfully identified variants associated with individual traits comprising MetS, the genetic basis and pathophysiological mechanisms underlying the clustering of these traits remain unclear. We conducted GWAS of MetS in 1427 Africans from Ghana and Nigeria followed by replication testing and meta-analysis in another continental African sample from Kenya. Further replication testing was performed in an African American sample from the Atherosclerosis Risk in Communities (ARIC) study. We found two African-ancestry specific variants that were significantly associated with MetS: SNP rs73989312[A] near CA10 that conferred increased risk (P=3.86 × 10(-8), OR=6.80) and SNP rs77244975[C] in CTNNA3 that conferred protection against MetS (P=1.63 × 10(-8), OR=0.15). Given the exclusive expression of CA10 in the brain, our CA10 finding strengthens previously reported link between brain function and MetS. We also identified two variants that are not African specific: rs76822696[A] near RALYL associated with increased MetS risk (P=7.37 × 10(-9), OR=1.59) and rs7964157[T] near KSR2 associated with reduced MetS risk (P=4.52 × 10(-8), Pmeta=7.82 × 10(-9), OR=0.53). The KSR2 locus displayed pleiotropic associations with triglyceride and measures of blood pressure. Rare KSR2 mutations have been reported to be associated with early onset obesity and insulin resistance. Finally, we replicated the LPL and CETP loci previously found to be associated with MetS in Europeans. These findings provide novel insights into the genetics of MetS in Africans and demonstrate the utility of conducting trans-ethnic disease gene mapping studies for testing the cosmopolitan significance of GWAS signals of cardio-metabolic traits.
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Affiliation(s)
- Fasil Tekola-Ayele
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
| | - Ayo P Doumatey
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Daniel Shriner
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Amy R Bentley
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Guanjie Chen
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jie Zhou
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | | | | | - Johnnie Oli
- University of Nigeria Teaching Hospital, Enugu, Nigeria
| | | | - Benjami A Eghan
- University of Science and Technology, Department of Medicine, Kumasi, Ghana
| | | | - Clement Adebamowo
- Department of Epidemiology and Public Health, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Albert Amoah
- University of Ghana Medical School, Department of Medicine, Accra, Ghana
| | - Joseph Acheampong
- University of Science and Technology, Department of Medicine, Kumasi, Ghana
| | - Adebowale Adeyemo
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Charles N Rotimi
- Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA.
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72
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Guo XY, Liu J, Gao Y. Nonalcoholic fatty liver disease: Pathogenesis and incretin based therapies. Shijie Huaren Xiaohua Zazhi 2015; 23:4990-4996. [DOI: 10.11569/wcjd.v23.i31.4990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Nonalcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome (MS). The current treatment of non-alcoholic fatty liver disease (NAFLD) principally involves amelioration of MS components by lifestyle modification. Effective pharmacological agents for fatty liver treatment are lacking. Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that can enhance glucose-stimulated insulin secretion, and represent a new class of drugs for treatment of type 2 diabetes, including glucagon-like peptide 1 analogues and dipeptidyl aminopeptidase 4 inhibitors. There are several experimental and clinical trials exploring the efficacy of incretin based therapies in NAFLD treatment, however, further studies are needed to assess the long-term effect of incretin based therapies on NAFLD.
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73
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Sokolovska J, Isajevs S, Rostoka E, Sjakste T, Trapiņa I, Ošiņa K, Paramonova N, Sjakste N. Changes in glucose transporter expression and nitric oxide production are associated with liver injury in diabetes. Cell Biochem Funct 2015; 33:367-74. [PMID: 26347179 DOI: 10.1002/cbf.3123] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 05/29/2015] [Accepted: 06/08/2015] [Indexed: 12/21/2022]
Abstract
In diabetes mellitus (DM), both hyperglycaemia and hyperlipidaemia can initiate accumulation of fat in the liver, which might be further mediated by inducible nitric oxide synthase. We have studied changes in GLUT1, nitric oxide (NO(·)) concentration and liver damage in two rat DM models. STZ model was induced by strepozotocin 50 mg/kg. HS model was induced by high-fat diet and 30 mg/kg streptozotocin. GLUT1 expression was studied by means of real-time RT-PCR and immunohistochemistry. Production of NO(·) was monitored by means of erythrocyte sedimentation rate spectroscopy of Fe-DETC-NO complex. Liver damage was assessed using histological activity index (HAI). NO(·) concentration was increased in the liver of STZ rats, but it did not change in HS rats (control 36.8 ± 10.3; STZ 142.1 ± 31.1; HS 35.4 ± 9.8 ng/g). Liver HAI was higher in STZ group, 8.6 ± 0.17 versus HS 4.7 ± 0.31, p < 0.05. GLUT1 protein expression was elevated only in STZ group, 16 ± 3 cells/mm(2) versus Control 5 ± 2 cells/mm(2), p = 0.007. Hyperglycaemia sooner causes severe liver damage in rat models of DM, compared with hyperlipidaemia, and is associated with increased NO(·) production. GLUT1 transporter expression might be involved in toxic effects of glucose in the liver. We have obtained novel data about association of GLUT1 expression and NO(·) metabolism in the pathogenesis of liver injury in DM. Increased GLUT1 expression was observed together with overproduction of NO(·) and pronounced liver injury in severely hyperglycaemic rats. On the contrary, moderately hyperglycaemic hyperlipidaemic rats developed only moderate liver steatosis and no increase in GLUT1 and NO(·). GLUT1 overexpression might be implicated in the toxic effects of glucose in the liver. Glycotoxicity is associated with oxidative stress and NO(·) hyperproduction. GLUT1 and NO(·) metabolism might become novel therapeutic targets in liver steatosis.
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Affiliation(s)
| | - Sergejs Isajevs
- Biochemistry Team, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Evita Rostoka
- Biochemistry Team, Latvian Institute of Organic Synthesis, Riga, Latvia
| | - Tatjana Sjakste
- Genomics and Bioinformatics Group, Institute of Biology of the University of Latvia, Salaspils, Latvia
| | - Ilva Trapiņa
- Genomics and Bioinformatics Group, Institute of Biology of the University of Latvia, Salaspils, Latvia
| | - Kristīne Ošiņa
- Genomics and Bioinformatics Group, Institute of Biology of the University of Latvia, Salaspils, Latvia
| | - Natalia Paramonova
- Genomics and Bioinformatics Group, Institute of Biology of the University of Latvia, Salaspils, Latvia
| | - Nikolajs Sjakste
- Biochemistry Team, Latvian Institute of Organic Synthesis, Riga, Latvia
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74
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Liu L, Jiang L, Ding XD, Liu JF, Zhang Q. The regulation of glucose on milk fat synthesis is mediated by the ubiquitin-proteasome system in bovine mammary epithelial cells. Biochem Biophys Res Commun 2015; 465:59-63. [DOI: 10.1016/j.bbrc.2015.07.129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 07/25/2015] [Indexed: 10/23/2022]
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75
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Díaz-Ruiz A, Guzmán-Ruiz R, Moreno NR, García-Rios A, Delgado-Casado N, Membrives A, Túnez I, El Bekay R, Fernández-Real JM, Tovar S, Diéguez C, Tinahones FJ, Vázquez-Martínez R, López-Miranda J, Malagón MM. Proteasome Dysfunction Associated to Oxidative Stress and Proteotoxicity in Adipocytes Compromises Insulin Sensitivity in Human Obesity. Antioxid Redox Signal 2015; 23:597-612. [PMID: 25714483 PMCID: PMC4554552 DOI: 10.1089/ars.2014.5939] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AIMS Obesity is characterized by a low-grade systemic inflammatory state and adipose tissue (AT) dysfunction, which predispose individuals to the development of insulin resistance (IR) and metabolic disease. However, a subset of obese individuals, referred to as metabolically healthy obese (MHO) individuals, are protected from obesity-associated metabolic abnormalities. Here, we aim at identifying molecular factors and pathways in adipocytes that are responsible for the progression from the insulin-sensitive to the insulin-resistant, metabolically unhealthy obese (MUHO) phenotype. RESULTS Proteomic analysis of paired samples of adipocytes from subcutaneous (SC) and omental (OM) human AT revealed that both types of cells are altered in the MUHO state. Specifically, the glutathione redox cycle and other antioxidant defense systems as well as the protein-folding machinery were dysregulated and endoplasmic reticulum stress was increased in adipocytes from IR subjects. Moreover, proteasome activity was also compromised in adipocytes of MUHO individuals, which was associated with enhanced accumulation of oxidized and ubiquitinated proteins in these cells. Proteasome activity was also impaired in adipocytes of diet-induced obese mice and in 3T3-L1 adipocytes exposed to palmitate. In line with these data, proteasome inhibition significantly impaired insulin signaling in 3T3-L1 adipocytes. INNOVATION This study provides the first evidence of the occurrence of protein homeostasis deregulation in adipocytes in human obesity, which, together with oxidative damage, interferes with insulin signaling in these cells. CONCLUSION Our results suggest that proteasomal dysfunction and impaired proteostasis in adipocytes, resulting from protein oxidation and/or misfolding, constitute major pathogenic mechanisms in the development of IR in obesity.
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Affiliation(s)
- Alberto Díaz-Ruiz
- 1 Department of Cell Biology, Physiology, and Immunology, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain .,2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain
| | - Rocío Guzmán-Ruiz
- 1 Department of Cell Biology, Physiology, and Immunology, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain .,2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain
| | - Natalia R Moreno
- 1 Department of Cell Biology, Physiology, and Immunology, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain .,2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain
| | - Antonio García-Rios
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,3 Lipids and Atherosclerosis Unit, IMIBIC/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain
| | - Nieves Delgado-Casado
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,3 Lipids and Atherosclerosis Unit, IMIBIC/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain
| | - Antonio Membrives
- 4 Unidad de Gestión Clínica de Cirugía General y Digestivo. Sección de Obesidad, IMIBIC/Reina Sofia University Hospital , Córdoba, Spain
| | - Isaac Túnez
- 5 Department of Biochemistry and Molecular Biology, IMIBIC/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain
| | - Rajaa El Bekay
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,6 Biomedical Research Laboratory, Endocrinology Department, Hospital Virgen de la Victoria , Málaga, Spain
| | - José M Fernández-Real
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,7 Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomédica de Girona (IdIBGi) , Girona, Spain
| | - Sulay Tovar
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,8 Department of Physiology, School of Medicine-CIMUS-Instituto de Investigaciones Sanitarias (IDIS), University of Santiago de Compostela , Santiago de Compostela, A Coruña, Spain
| | - Carlos Diéguez
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,8 Department of Physiology, School of Medicine-CIMUS-Instituto de Investigaciones Sanitarias (IDIS), University of Santiago de Compostela , Santiago de Compostela, A Coruña, Spain
| | - Francisco J Tinahones
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,6 Biomedical Research Laboratory, Endocrinology Department, Hospital Virgen de la Victoria , Málaga, Spain
| | - Rafael Vázquez-Martínez
- 1 Department of Cell Biology, Physiology, and Immunology, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain .,2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain
| | - José López-Miranda
- 2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain .,3 Lipids and Atherosclerosis Unit, IMIBIC/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain
| | - María M Malagón
- 1 Department of Cell Biology, Physiology, and Immunology, Instituto Maimónides de Investigación Biomédica (IMIBIC)/Reina Sofia University Hospital/University of Córdoba , Córdoba, Spain .,2 CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Instituto de Salud Carlos III , Córdoba, Spain
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Salvadó L, Palomer X, Barroso E, Vázquez-Carrera M. Targeting endoplasmic reticulum stress in insulin resistance. Trends Endocrinol Metab 2015; 26:438-48. [PMID: 26078196 DOI: 10.1016/j.tem.2015.05.007] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 02/06/2023]
Abstract
The endoplasmic reticulum (ER) is involved in the development of insulin resistance and progression to type 2 diabetes mellitus (T2DM). Disruption of ER homeostasis leads to ER stress, which activates the unfolded protein response (UPR). This response is linked to different processes involved in the development of insulin resistance (IR) and T2DM, including inflammation, lipid accumulation, insulin biosynthesis, and β-cell apoptosis. Understanding the mechanisms by which disruption of ER homeostasis leads to IR and its progression to T2DM may offer new pharmacological targets for the treatment and prevention of these diseases. Here, we examine ER stress, the UPR, and downstream pathways in insulin sensitive tissues, and in IR, and offer insights towards therapeutic strategies.
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Affiliation(s)
- Laia Salvadó
- Department of Pharmacology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain
| | - Xavier Palomer
- Department of Pharmacology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain
| | - Emma Barroso
- Department of Pharmacology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain
| | - Manuel Vázquez-Carrera
- Department of Pharmacology and Therapeutic Chemistry, Faculty of Pharmacy, University of Barcelona, Institute of Biomedicine of the University of Barcelona (IBUB), Barcelona, Spain; Spanish Biomedical Research Centre in Diabetes and Associated Metabolic Diseases (CIBERDEM)-Instituto de Salud Carlos III, Madrid, Spain.
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77
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Shevalye H, Yorek MS, Coppey LJ, Holmes A, Harper MM, Kardon RH, Yorek MA. Effect of enriching the diet with menhaden oil or daily treatment with resolvin D1 on neuropathy in a mouse model of type 2 diabetes. J Neurophysiol 2015; 114:199-208. [PMID: 25925322 DOI: 10.1152/jn.00224.2015] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 04/24/2015] [Indexed: 12/14/2022] Open
Abstract
The purpose of this study was to determine the effect of supplementing the diet of a mouse model of type 2 diabetes with menhaden (fish) oil or daily treatment with resolvin D1 on diabetic neuropathy. The end points evaluated included motor and sensory nerve conduction velocity, thermal sensitivity, innervation of sensory nerves in the cornea and skin, and the retinal ganglion cell complex thickness. Menhaden oil is a natural source for n-3 polyunsaturated fatty acids, which have been shown to have beneficial effects in other diseases. Resolvin D1 is a metabolite of docosahexaenoic acid and is known to have anti-inflammatory and neuroprotective properties. To model type 2 diabetes, mice were fed a high-fat diet for 8 wk followed by a low dosage of streptozotocin. After 8 wk of hyperglycemia, mice in experimental groups were treated for 6 wk with menhaden oil in the diet or daily injections of 1 ng/g body wt resolvin D1. Our findings show that menhaden oil or resolvin D1 did not improve elevated blood glucose, HbA1C, or glucose utilization. Untreated diabetic mice were thermal hypoalgesic, had reduced motor and sensory nerve conduction velocities, had decreased innervation of the cornea and skin, and had thinner retinal ganglion cell complex. These end points were significantly improved with menhaden oil or resolvin D1 treatment. Exogenously, resolvin D1 stimulated neurite outgrowth from primary cultures of dorsal root ganglion neurons from normal mice. These studies suggest that n-3 polyunsaturated fatty acids derived from fish oil could be an effective treatment for diabetic neuropathy.
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Affiliation(s)
- Hanna Shevalye
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Matthew S Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Lawrence J Coppey
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa
| | - Amey Holmes
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa
| | - Matthew M Harper
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Randy H Kardon
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and
| | - Mark A Yorek
- Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Department of Internal Medicine, University of Iowa, Iowa City, Iowa; Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa; and Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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78
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Troxerutin inhibits 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47)-induced hepatocyte apoptosis by restoring proteasome function. Toxicol Lett 2015; 233:246-57. [DOI: 10.1016/j.toxlet.2015.01.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/30/2014] [Accepted: 01/25/2015] [Indexed: 12/25/2022]
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79
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Abstract
This chapter presents two methods for assessment of proteasome function. The first is a modification of the standard fluorogenic peptide cleavage assay which takes into account the effect of ATP on proteasome activity. This method is described in both its macro and high throughput micro-assay forms. The second is the Proteasome Constitutive Immuno-Subunit (active site) ELISA or ProCISE method. ProCISE is a modification of active site directed probe analysis and allows for convenient differentiation between active constitutive and immuno-subunits. While the utility of measuring proteasome activity and its relationship to cytokine action and inflammation are clear, the assessment and interpretation is not always straightforward. Therefore, we also discuss the pitfalls of the standard fluorogenic assay, particularly in the interpretation of results obtained, and the advantages of the newer, ProCISE assay.
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Affiliation(s)
- Christopher J Kirk
- Onyx Pharmaceuticals, 249 Grand Avenue South, San Francisco, CA, 94080, USA
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80
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Zhang Y, Ye M, Chen LJ, Li M, Tang Z, Wang C. Role of the ubiquitin-proteasome system and autophagy in regulation of insulin sensitivity in serum-starved 3T3-L1 adipocytes. Endocr J 2015; 62:673-86. [PMID: 25959705 DOI: 10.1507/endocrj.ej15-0030] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ubiquitin-proteasome system (UPS) and autophagy are two conserved intracellular proteolytic pathways, responsible for degradation of most cellular proteins in living cells. Currently, both the UPS and autophagy have been suggested to be associated with pathogenesis of insulin resistance and diabetes. However, underlying mechanism remains largely unknown. The purpose of the present study is to investigate the impact of the UPS and autophagy on insulin sensitivity in serum-starved 3T3-L1 adipocytes. Our results show that serum depletion resulted in activation of the UPS and autophagy, accompanied with increased insulin sensitivity. Inhibition of the UPS with bortezomib (BZM), a highly selective, reversible 26S proteasome inhibitor induced compensatory activation of autophagy but did not affect significantly insulin action. Genetic and pharmacological inhibition of autophagy dramatically mitigated serum starvation-elevated insulin sensitivity. In addition, autophagy inhibition compromised UPS function and led to endoplasmic reticulum (ER) stress and unfolded protein response (UPR). Inability of the UPS by BMZ exacerbated autophagy inhibition-induced ER stress and UPR. These results suggest that protein quality control maintained by the UPS and autophagy is required for preserving insulin sensitivity. Importantly, adaptive activation of autophagy plays a critical role in serum starvation-induced insulin sensitization in 3T3-L1 adipocytes.
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Affiliation(s)
- Yemin Zhang
- Department of Pathology & Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
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81
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Arruda AP, Pers BM, Parlakgül G, Güney E, Inouye K, Hotamisligil GS. Chronic enrichment of hepatic endoplasmic reticulum-mitochondria contact leads to mitochondrial dysfunction in obesity. Nat Med 2014; 20:1427-35. [PMID: 25419710 PMCID: PMC4412031 DOI: 10.1038/nm.3735] [Citation(s) in RCA: 485] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 09/17/2014] [Indexed: 12/11/2022]
Abstract
Proper function of the endoplasmic reticulum (ER) and mitochondria is crucial for cellular homeostasis, and dysfunction at either site has been linked to pathophysiological states, including metabolic diseases. Although the ER and mitochondria play distinct cellular roles, these organelles also form physical interactions with each other at sites defined as mitochondria-associated ER membranes (MAMs), which are essential for calcium, lipid and metabolite exchange. Here we show that in the liver, obesity leads to a marked reorganization of MAMs resulting in mitochondrial calcium overload, compromised mitochondrial oxidative capacity and augmented oxidative stress. Experimental induction of ER-mitochondria interactions results in oxidative stress and impaired metabolic homeostasis, whereas downregulation of PACS-2 or IP3R1, proteins important for ER-mitochondria tethering or calcium transport, respectively, improves mitochondrial oxidative capacity and glucose metabolism in obese animals. These findings establish excessive ER-mitochondrial coupling as an essential component of organelle dysfunction in obesity that may contribute to the development of metabolic pathologies such as insulin resistance and diabetes.
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Affiliation(s)
- Ana Paula Arruda
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
| | - Benedicte M Pers
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
| | - Güneş Parlakgül
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
| | - Ekin Güney
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
| | - Karen Inouye
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
| | - Gökhan S Hotamisligil
- Department of Genetics and Complex Diseases and Sabri Ülker Center, Harvard School of Public Health and Broad Institute of Harvard and MIT, Boston, Massachusetts, USA
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Li H, Dusseault J, Larose L. Nck1 depletion induces activation of the PI3K/Akt pathway by attenuating PTP1B protein expression. Cell Commun Signal 2014; 12:71. [PMID: 25398386 PMCID: PMC4236421 DOI: 10.1186/s12964-014-0071-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 10/19/2014] [Indexed: 12/17/2022] Open
Abstract
Background Activation of the PI3K/Akt pathway mediates crucial cellular functions regulated by receptor tyrosine kinases, such as cell growth, proliferation, survival and metabolism. Previously, we reported that the whole-body knockout of the Src homology domain-containing adaptor protein Nck1 improves overall glucose homeostasis and insulin-induced activation of the PI3K/Akt pathway in liver of obese mice. The aim of the current study is to elucidate the mechanism by which Nck1 depletion regulates hepatic insulin signaling. Results Here, we demonstrate that Nck1 regulates the activation of the PI3K/Akt pathway in a protein tyrosine phosphatase 1B (PTP1B)-dependent mechanism. Indeed, depletion of Nck1 by siRNA in HepG2 cells enhances PI3K-dependent basal and growth factor-induced Akt activation. In accordance, primary hepatocytes isolated from Nck1−/− mice also display enhanced Akt activation in response to insulin. Activation of the PI3K/Akt pathway in Nck1-depleted HepG2 cells relies on higher levels of tyrosine-phosphorylated proteins and correlates with decreased PTP1B levels. Interestingly, Nck1 and PTP1B in cells are found in a common molecular complex and their interaction is dependent on the SH3 domains of Nck1. Finally, Nck1 depletion in HepG2 cells neither affects PTP1B gene transcription nor PTP1B protein stability, suggesting that Nck1 modulates PTP1B expression at the translational level. Conclusion Our study provides strong evidence supporting that the adaptor protein Nck1 interacts with PTP1B and also regulates PTP1B expression. In this manner, Nck1 plays a role in regulating the PI3K/Akt pathway.
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Affiliation(s)
- Hui Li
- Department of Medicine, Polypeptide Laboratory, McGill University and The Research Institute of McGill University Health Centre, Montreal, QC, Canada.
| | - Julie Dusseault
- Department of Medicine, Polypeptide Laboratory, McGill University and The Research Institute of McGill University Health Centre, Montreal, QC, Canada.
| | - Louise Larose
- Department of Medicine, Polypeptide Laboratory, McGill University and The Research Institute of McGill University Health Centre, Montreal, QC, Canada.
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Reddy SS, Shruthi K, Reddy VS, Raghu G, Suryanarayana P, Giridharan N, Reddy GB. Altered ubiquitin-proteasome system leads to neuronal cell death in a spontaneous obese rat model. Biochim Biophys Acta Gen Subj 2014; 1840:2924-34. [DOI: 10.1016/j.bbagen.2014.06.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 05/29/2014] [Accepted: 06/10/2014] [Indexed: 12/11/2022]
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Chaperoning to the metabolic party: The emerging therapeutic role of heat-shock proteins in obesity and type 2 diabetes. Mol Metab 2014; 3:781-93. [PMID: 25379403 PMCID: PMC4216407 DOI: 10.1016/j.molmet.2014.08.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/19/2014] [Accepted: 08/22/2014] [Indexed: 12/17/2022] Open
Abstract
Background From their initial, accidental discovery 50 years ago, the highly conserved Heat Shock Proteins (HSPs) continue to exhibit fundamental roles in the protection of cell integrity. Meanwhile, in the midst of an obesity epidemic, research demonstrates a key involvement of low grade inflammation, and mitochondrial dysfunction amongst other mechanisms, in the pathology of insulin resistance and type 2 diabetes mellitus (T2DM). In particular, tumor necrosis factor alpha (TNFα), endoplasmic reticulum (ER) and oxidative stress all appear to be associated with obesity and stimulate inflammatory kinases such as c jun amino terminal kinase (JNK), inhibitor of NF-κβ kinase (IKK) and protein kinase C (PKC) which in turn, inhibit insulin signaling. Mitochondrial dysfunction in skeletal muscle has also been proposed to be prominent in the pathogenesis of T2DM either by reducing the ability to oxidize fatty acids, leading to the accumulation of deleterious lipid species in peripheral tissues such as skeletal muscle and liver, or by altering the cellular redox state. Since HSPs act as molecular chaperones and demonstrate crucial protective functions in stressed cells, we and others have postulated that the manipulation of HSP expression in metabolically relevant tissues represents a therapeutic avenue for obesity-induced insulin resistance. Scope of Review This review summarizes the literature from both animal and human studies, that has examined how HSPs, particularly the inducible HSP, Heat Shock Protein 72 (Hsp72) alters glucose homeostasis and the possible approaches to modulating Hsp72 expression. A summation of the role of chemical chaperones in metabolic disorders is also included. Major Conclusions Targeted manipulation of Hsp72 or use of chemical chaperiones may have clinical utility in treating metabolic disorders such as insulin resistance and T2DM.
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85
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Jaisson S, Gillery P. Impaired proteostasis: role in the pathogenesis of diabetes mellitus. Diabetologia 2014; 57:1517-27. [PMID: 24816368 DOI: 10.1007/s00125-014-3257-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 04/08/2014] [Indexed: 01/06/2023]
Abstract
In living organisms, proteins are regularly exposed to 'molecular ageing', which corresponds to a set of non-enzymatic modifications that progressively cause irreversible damage to proteins. This phenomenon is greatly amplified under pathological conditions, such as diabetes mellitus. For their survival and optimal functioning, cells have to maintain protein homeostasis, also called 'proteostasis'. This process acts to maintain a high proportion of functional and undamaged proteins. Different mechanisms are involved in proteostasis, among them degradation systems (the main intracellular proteolytic systems being proteasome and lysosomes), folding systems (including molecular chaperones), and enzymatic mechanisms of protein repair. There is growing evidence that the disruption of proteostasis may constitute a determining event in pathophysiology. The aim of this review is to demonstrate how such a dysregulation may be involved in the pathogenesis of diabetes mellitus and in the onset of its long-term complications.
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Affiliation(s)
- Stéphane Jaisson
- Laboratory of Medical Biochemistry and Molecular Biology, University of Reims Champagne Ardenne, Reims, France,
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86
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Hayashi H, Yamada R, Das SS, Sato T, Takahashi A, Hiratsuka M, Hirasawa N. Glucagon-like peptide-1 production in the GLUTag cell line is impaired by free fatty acids via endoplasmic reticulum stress. Metabolism 2014; 63:800-11. [PMID: 24680601 DOI: 10.1016/j.metabol.2014.02.012] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 02/15/2014] [Accepted: 02/17/2014] [Indexed: 12/16/2022]
Abstract
OBJECTS Glucagon-like peptide-1 (GLP-1) is secreted from intestinal L cells, enhances glucose-stimulated insulin secretion, and protects pancreas beta cells. However, few studies have examined hypernutrition stress in L cells and its effects on their function. Here, we demonstrated that a high-fat diet reduced glucose-stimulated secretion of GLP-1 and induced expression of an endoplasmic reticulum (ER) stress markers in the intestine of a diet-induced obesity mouse model. METHODS To clarify whether ER stress in L cells caused the attenuation of GLP-1 secretion, we treated the mouse intestinal L cell line, GLUTag cells with palmitate or oleate. RESULTS Palmitate, but not oleate caused ER stress and decreased the protein levels of prohormone convertase 1/3 (PC1/3), an essential enzyme in GLP-1 production. The same phenomena were observed in GLUTag cells treated with in ER stress inducer, thapsigargin. Moreover, oleate improved palmitate-induced ER stress, reduced protein and activity levels of PC1/3, and attenuated GLP-1 secretion from GLUTag cells. CONCLUSIONS/INTERPRETATION These results suggest that the intake of abundant saturated fatty acids induces ER stress in the intestine and decreases GLP-1 production.
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Affiliation(s)
- Hiroto Hayashi
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Ren Yamada
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Siddhartha Shankar Das
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Taiki Sato
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Aki Takahashi
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Masahiro Hiratsuka
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan
| | - Noriyasu Hirasawa
- Laboratory of Pharmacotherapy of Life-Style Related Diseases, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Miyagi, Japan.
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Abstract
PURPOSE OF REVIEW The endoplasmic reticulum (ER) maintains cellular metabolic homeostasis by coordinating protein synthesis, secretion activities, lipid biosynthesis and calcium (Ca²⁺) storage. In this review, we will discuss how altered ER homeostasis contributes to dysregulation of hepatic lipid metabolism and contributes to liver-associated metabolic diseases. RECENT FINDINGS Perturbed ER functions or accumulation of unfolded protein in the ER leads to the activation of the unfolded protein response (UPR) to protect the cell from ER stress. Recent findings pinpoint the key regulatory role of the UPR in hepatic lipid metabolism and demonstrate the potential causal mechanism of ER stress in metabolic dysregulation including diabetes and obesity. SUMMARY A wide range of factors can alter the protein-folding environment in the ER of hepatocytes and contribute to dysregulation of hepatic lipid metabolism and liver disease. The UPR constitutes a series of adaptive programs that preserve ER protein-folding environment and maintain hepatic lipid homeostasis. Signaling components of the UPR are emerging as potential targets for intervention and treatment of human liver-associated metabolic diseases.
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Affiliation(s)
- Shiyu Wang
- Degenerative Disease Research, Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
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Broca C, Varin E, Armanet M, Tourrel-Cuzin C, Bosco D, Dalle S, Wojtusciszyn A. Proteasome dysfunction mediates high glucose-induced apoptosis in rodent beta cells and human islets. PLoS One 2014; 9:e92066. [PMID: 24642635 PMCID: PMC3958412 DOI: 10.1371/journal.pone.0092066] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 02/17/2014] [Indexed: 01/23/2023] Open
Abstract
The ubiquitin/proteasome system (UPS), a major cellular protein degradation machinery, plays key roles in the regulation of many cell functions. Glucotoxicity mediated by chronic hyperglycaemia is detrimental to the function and survival of pancreatic beta cells. The aim of our study was to determine whether proteasome dysfunction could be involved in beta cell apoptosis in glucotoxic conditions, and to evaluate whether such a dysfunction might be pharmacologically corrected. Therefore, UPS activity was measured in GK rats islets, INS-1E beta cells or human islets after high glucose and/or UPS inhibitor exposure. Immunoblotting was used to quantify polyubiquitinated proteins, endoplasmic reticulum (ER) stress through CHOP expression, and apoptosis through the cleavage of PARP and caspase-3, whereas total cell death was detected through histone-associated DNA fragments measurement. In vitro, we found that chronic exposure of INS-1E cells to high glucose concentrations significantly decreases the three proteasome activities by 20% and leads to caspase-3-dependent apoptosis. We showed that pharmacological blockade of UPS activity by 20% leads to apoptosis in a same way. Indeed, ER stress was involved in both conditions. These results were confirmed in human islets, and proteasome activities were also decreased in hyperglycemic GK rats islets. Moreover, we observed that a high glucose treatment hypersensitized beta cells to the apoptotic effect of proteasome inhibitors. Noteworthily, the decreased proteasome activity can be corrected with Exendin-4, which also protected against glucotoxicity-induced apoptosis. Taken together, our findings reveal an important role of proteasome activity in high glucose-induced beta cell apoptosis, potentially linking ER stress and glucotoxicity. These proteasome dysfunctions can be reversed by a GLP-1 analog. Thus, UPS may be a potent target to treat deleterious metabolic conditions leading to type 2 diabetes.
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Affiliation(s)
- Christophe Broca
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Elodie Varin
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Mathieu Armanet
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Cécile Tourrel-Cuzin
- B2PE Laboratory (Biology & Pathology of Endocrine Pancreas), BFA Unit, Univ. Paris-Diderot, CNRS EAC4413, Paris, France
| | - Domenico Bosco
- Cell Isolation and Transplantation Center, Department of Surgery, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Stéphane Dalle
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
| | - Anne Wojtusciszyn
- CNRS UMR 5203, INSERM U661, and Montpellier 1 & 2 University, Institute of Functional Genomics, Montpellier, France
- Laboratory for Diabetes Cell Therapy, Institute for Research in Biotherapy, University Hospital St-Eloi, Montpellier, France
- Department of Endocrinology-Diabetes-Nutrition, University Hospital Lapeyronie, Montpellier, France
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Affiliation(s)
- Toshinari Takamura
- Department of Disease Control and Homeostasis, Kanazawa University Graduate School of Medical Sciences, Kanazawa, Ishikawa, Japan
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Dong S, Jia C, Zhang S, Fan G, Li Y, Shan P, Sun L, Xiao W, Li L, Zheng Y, Liu J, Wei H, Hu C, Zhang W, Chin YE, Zhai Q, Li Q, Liu J, Jia F, Mo Q, Edwards DP, Huang S, Chan L, O'Malley BW, Li X, Wang C. The REGγ proteasome regulates hepatic lipid metabolism through inhibition of autophagy. Cell Metab 2013; 18:380-91. [PMID: 24011073 PMCID: PMC3813599 DOI: 10.1016/j.cmet.2013.08.012] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 06/22/2013] [Accepted: 08/09/2013] [Indexed: 12/17/2022]
Abstract
The ubiquitin-proteasome and autophagy-lysosome systems are major proteolytic pathways, whereas function of the Ub-independent proteasome pathway is yet to be clarified. Here, we investigated roles of the Ub-independent REGγ-proteasome proteolytic system in regulating metabolism. We demonstrate that mice deficient for the proteasome activator REGγ exhibit dramatic autophagy induction and are protected against high-fat diet (HFD)-induced liver steatosis through autophagy. Molecularly, prevention of steatosis in the absence of REGγ entails elevated SirT1, a deacetylase regulating autophagy and metabolism. REGγ physically binds to SirT1, promotes its Ub-independent degradation, and inhibits its activity to deacetylate autophagy-related proteins, thereby inhibiting autophagy under normal conditions. Moreover, REGγ and SirT1 dissociate from each other through a phosphorylation-dependent mechanism under energy-deprived conditions, unleashing SirT1 to stimulate autophagy. These observations provide a function of the REGγ proteasome in autophagy and hepatosteatosis, underscoring mechanistically a crosstalk between the proteasome and autophagy degradation system in the regulation of lipid homeostasis.
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Affiliation(s)
- Shuxian Dong
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences, East China Normal University, Shanghai, 200241, China; Department of Molecular and Cellular Biology, Department of Medicine, The Dan L. Duncan Cancer Center, The Diabetes Research Center, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
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Kupca S, Sjakste T, Paramonova N, Sugoka O, Rinkuza I, Trapina I, Daugule I, Sipols AJ, Rumba-Rozenfelde I. Association of obesity with proteasomal gene polymorphisms in children. J Obes 2013; 2013:638154. [PMID: 24455213 PMCID: PMC3880696 DOI: 10.1155/2013/638154] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/29/2013] [Accepted: 11/22/2013] [Indexed: 11/17/2022] Open
Abstract
The aim of this study was to ascertain possible associations between childhood obesity, its anthropometric and clinical parameters, and three loci of proteasomal genes rs2277460 (PSMA6 c.-110C>A), rs1048990 (PSMA6 c.-8C>G), and rs2348071 (PSMA3 c. 543+138G>A) implicated in obesity-related diseases. Obese subjects included 94 otherwise healthy children in Latvia. Loci were genotyped and then analyzed using polymerase chain reactions, with results compared to those of 191 nonobese controls. PSMA3 SNP frequency differences between obese children and controls, while not reaching significance, suggested a trend. These differences, however, proved highly significant (P < 0.002) in the subset of children reporting a family history of obesity. Among obese children denying such history, PSMA6 c.-8C>G SNP differences, while being nonsignificant, likewise suggested a trend in comparison to the nonobese controls. No PSMA6 c.-110C>A SNP differences were detected in the obese group or its subsets. Finally, PSMA3 SNP differences were significantly associated (P < 0.05) with circulating low-density lipoprotein cholesterol (LDL) levels. Our results clearly implicate the PSMA3 gene locus as an obesity risk factor in those Latvian children with a family history of obesity. While being speculative, the clinical results are suggestive of altered circulatory LDL levels playing a possible role in the etiology of obesity in the young.
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Affiliation(s)
- Sarmite Kupca
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
- Institute of Experimental and Clinical Medicine, University of Latvia, No. 4 Ojara Vaciesa Street, Riga 1004, Latvia
| | - Tatjana Sjakste
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Natalija Paramonova
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Olga Sugoka
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Irena Rinkuza
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
| | - Ilva Trapina
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Biology, University of Latvia, Miera Street 3, Salaspils 2169, Latvia
| | - Ilva Daugule
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
| | - Alfred J. Sipols
- Faculty of Medicine, University of Latvia, Sarlotes Street 1a, Riga 1001, Latvia
- Institute of Experimental and Clinical Medicine, University of Latvia, No. 4 Ojara Vaciesa Street, Riga 1004, Latvia
- *Alfred J. Sipols:
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