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Martins AR, Nachbar RT, Gorjao R, Vinolo MA, Festuccia WT, Lambertucci RH, Cury-Boaventura MF, Silveira LR, Curi R, Hirabara SM. Mechanisms underlying skeletal muscle insulin resistance induced by fatty acids: importance of the mitochondrial function. Lipids Health Dis 2012; 11:30. [PMID: 22360800 PMCID: PMC3312873 DOI: 10.1186/1476-511x-11-30] [Citation(s) in RCA: 190] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 02/23/2012] [Indexed: 01/06/2023] Open
Abstract
Insulin resistance condition is associated to the development of several syndromes, such as obesity, type 2 diabetes mellitus and metabolic syndrome. Although the factors linking insulin resistance to these syndromes are not precisely defined yet, evidence suggests that the elevated plasma free fatty acid (FFA) level plays an important role in the development of skeletal muscle insulin resistance. Accordantly, in vivo and in vitro exposure of skeletal muscle and myocytes to physiological concentrations of saturated fatty acids is associated with insulin resistance condition. Several mechanisms have been postulated to account for fatty acids-induced muscle insulin resistance, including Randle cycle, oxidative stress, inflammation and mitochondrial dysfunction. Here we reviewed experimental evidence supporting the involvement of each of these propositions in the development of skeletal muscle insulin resistance induced by saturated fatty acids and propose an integrative model placing mitochondrial dysfunction as an important and common factor to the other mechanisms.
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Affiliation(s)
- Amanda R Martins
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Avenida Professor Lineu Prestes 1524, Butantã, São Paulo, SP, Brazil
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302
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Kassab A, Piwowar A. Cell oxidant stress delivery and cell dysfunction onset in type 2 diabetes. Biochimie 2012; 94:1837-48. [PMID: 22333037 DOI: 10.1016/j.biochi.2012.01.020] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2011] [Accepted: 01/25/2012] [Indexed: 01/18/2023]
Abstract
Most known pathways of diabetic complications involve oxidative stress. The mitochondria electron transport chain is a significant source of reactive oxygen species (ROS) in insulin secretory cells, insulin peripheral sensitive cells and endothelial cells. Elevated intracellular glucose level induces tricarboxylic acid cycle electron donor overproduction and mitochondrial proton gradient increase leading to an increase in electron transporter lifetime. Subsequently, the electrons leaked combine with respiratory oxygen (O(2)) resulting in superoxide anion ((•)O(2)(-)) production. Advanced glycation end products derive ROS via interaction with their receptors. Elevated diacylglycerol and ROS activate the protein kinase C pathway which, in turn, activates NADPH oxidases. A vicious circle of pathway derived ROS installs. Pathologic pathways induced ROS are activated and persistent though glycemia returns to normal due to hyperglycemia memory. Endothelial nitric oxide synthase may produce both superoxide anion ((•)O(2)(-)) and nitric oxide (NO) leading to peroxynitrite ((•)ONOO(-)) generation. Homocysteine is also implicated in oxidative stress pathogenesis. In this paper we have highlighted the pathologic mechanisms of ROS on atherosclerosis, renal dysfunction, retina dysfunction and nerve dysfunction in type 2 diabetes. Cell oxidant stress delivery have pivotal role in cell dysfunction onset and progression of angiopathies but an early introduction of good glycemic control may protect cells more efficiently than antioxidants.
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Affiliation(s)
- Asma Kassab
- Biochemistry Laboratory, CHU Farhat Hached, Sousse, Tunisia.
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303
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Wang Y. Small lipid-binding proteins in regulating endothelial and vascular functions: focusing on adipocyte fatty acid binding protein and lipocalin-2. Br J Pharmacol 2012; 165:603-21. [PMID: 21658023 PMCID: PMC3315034 DOI: 10.1111/j.1476-5381.2011.01528.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 05/26/2011] [Accepted: 05/31/2011] [Indexed: 12/13/2022] Open
Abstract
UNLABELLED Dysregulated production of adipokines from adipose tissue plays a critical role in the development of obesity-associated cardiovascular abnormalities. A group of adipokines, including adipocyte fatty acid binding protein (A-FABP) and lipocalin-2, possess specific lipid-binding activity and are up-regulated in obese human subjects and animal models. They act as lipid chaperones to promote lipotoxicity in endothelial cells and cause endothelial dysfunction under obese conditions. However, different small lipid-binding proteins modulate the development of vascular complications in distinctive manners, which are partly attributed to their specialized structural features and functionalities. By focusing on A-FABP and lipocalin-2, this review summarizes recent advances demonstrating the causative roles of these newly identified adipose tissue-derived lipid chaperones in obesity-related endothelial dysfunction and cardiovascular complications. The specific lipid-signalling mechanisms mediated by these two proteins are highlighted to support their specialized functions. In summary, A-FABP and lipocalin-2 represent potential therapeutic targets to design drugs for preventing vascular diseases associated with obesity. LINKED ARTICLES This article is part of a themed section on Fat and Vascular Responsiveness. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2012.165.issue-3.
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Affiliation(s)
- Yu Wang
- Department of Pharmacology and Pharmacy, Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong.
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304
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Yu ZW, Li D, Ling WH, Jin TR. Role of nuclear factor (erythroid-derived 2)-like 2 in metabolic homeostasis and insulin action: A novel opportunity for diabetes treatment? World J Diabetes 2012; 3:19-28. [PMID: 22253942 PMCID: PMC3258535 DOI: 10.4239/wjd.v3.i1.19] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 11/18/2011] [Accepted: 01/09/2012] [Indexed: 02/05/2023] Open
Abstract
Redox balance is fundamentally important for physiological homeostasis. Pathological factors that disturb this dedicated balance may result in oxidative stress, leading to the development or aggravation of a variety of diseases, including diabetes mellitus, cardiovascular diseases, metabolic syndrome as well as inflammation, aging and cancer. Thus, the capacity of endogenous free radical clearance can be of patho-physiological importance; in this regard, the major reactive oxygen species defense machinery, the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) system needs to be precisely modulated in response to pathological alterations. While oxidative stress is among the early events that lead to the development of insulin resistance, the activation of Nrf2 scavenging capacity leads to insulin sensitization. Furthermore, Nrf2 is evidently involved in regulating lipid metabolism. Here we summarize recent findings that link the Nrf2 system to metabolic homeostasis and insulin action and present our view that Nrf2 may serve as a novel drug target for diabetes and its complications.
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Affiliation(s)
- Zhi-Wen Yu
- Zhi-Wen Yu, Dan Li, Wen-Hua Ling, Tian-Ru Jin, Guandong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, Public Health Institute, Sun Yat-Sen University, Guangzhou 510080, Guangdong Province, China
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305
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Yuan L, Lin W, Xie Y, Chen B, Zhu S. Single Fluorescent Probe Responds to H2O2, NO, and H2O2/NO with Three Different Sets of Fluorescence Signals. J Am Chem Soc 2011; 134:1305-15. [DOI: 10.1021/ja2100577] [Citation(s) in RCA: 327] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Lin Yuan
- State Key Laboratory of Chemo/Biosensing and Chemometrics,
College of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, P. R. China
| | - Weiying Lin
- State Key Laboratory of Chemo/Biosensing and Chemometrics,
College of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, P. R. China
| | - Yinan Xie
- State Key Laboratory of Chemo/Biosensing and Chemometrics,
College of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, P. R. China
| | - Bin Chen
- State Key Laboratory of Chemo/Biosensing and Chemometrics,
College of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, P. R. China
| | - Sasa Zhu
- State Key Laboratory of Chemo/Biosensing and Chemometrics,
College of Chemistry and Chemical Engineering, Hunan University, Changsha
410082, P. R. China
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306
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Reactive oxygen species in skeletal muscle signaling. JOURNAL OF SIGNAL TRANSDUCTION 2011; 2012:982794. [PMID: 22175016 PMCID: PMC3235811 DOI: 10.1155/2012/982794] [Citation(s) in RCA: 249] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 08/25/2011] [Indexed: 12/13/2022]
Abstract
Generation of reactive oxygen species (ROS) is a ubiquitous phenomenon in eukaryotic cells' life. Up to the 1990s of the past century, ROS have been solely considered as toxic species resulting in oxidative stress, pathogenesis and aging. However, there is now clear evidence that ROS are not merely toxic species but also-within certain concentrations-useful signaling molecules regulating physiological processes. During intense skeletal muscle contractile activity myotubes' mitochondria generate high ROS flows: this renders skeletal muscle a tissue where ROS hold a particular relevance. According to their hormetic nature, in muscles ROS may trigger different signaling pathways leading to diverging responses, from adaptation to cell death. Whether a "positive" or "negative" response will prevail depends on many variables such as, among others, the site of ROS production, the persistence of ROS flow or target cells' antioxidant status. In this light, a specific threshold of physiological ROS concentrations above which ROS exert negative, toxic effects is hard to determine, and the concept of "physiologically compatible" levels of ROS would better fit with such a dynamic scenario. In this review these concepts will be discussed along with the most relevant signaling pathways triggered and/or affected by ROS in skeletal muscle.
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307
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Zhang Y, Du Y, Le W, Wang K, Kieffer N, Zhang J. Redox control of the survival of healthy and diseased cells. Antioxid Redox Signal 2011; 15:2867-908. [PMID: 21457107 DOI: 10.1089/ars.2010.3685] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Abstract Cellular redox homeostasis is the first line of defense against diverse stimuli and is crucial for various biological processes. Reactive oxygen species (ROS), byproducts of numerous cellular events, may serve in turn as signaling molecules to regulate cellular processes such as proliferation, differentiation, and apoptosis. However, when overproduced ROS fail to be scavenged by the antioxidant system, they may damage cellular components, giving rise to senescent, degenerative, or fatal lesions in cells. Accordingly, this review not only covers general mechanisms of ROS production under different conditions, but also focuses on various types of ROS-involved diseases, including atherosclerosis, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, and cancer. In addition, potentially therapeutic agents and approaches are reviewed in a relatively comprehensive manner. However, due to the complexity of ROS and their cellular impacts, we believe that the goal to design more effective approaches or agents may require a better understanding of mechanisms of ROS production, particularly their multifaceted impacts in disease at biochemical, molecular, genetic, and epigenetic levels. Thus, it requires additional tools of omics in systems biology to achieve such a goal. Antioxid. Redox Signal. 15, 2867-2908.
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Affiliation(s)
- Yuxing Zhang
- Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTU-SM), Shanghai, China
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308
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Golbidi S, Badran M, Laher I. Diabetes and alpha lipoic Acid. Front Pharmacol 2011; 2:69. [PMID: 22125537 PMCID: PMC3221300 DOI: 10.3389/fphar.2011.00069] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 10/18/2011] [Indexed: 12/25/2022] Open
Abstract
Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E, and glutathione. It also boosts antioxidant defense system through Nrf-2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.
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Affiliation(s)
- Saeid Golbidi
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia Vancouver, BC, Canada
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309
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Chiurchiù V, Maccarrone M. Chronic inflammatory disorders and their redox control: from molecular mechanisms to therapeutic opportunities. Antioxid Redox Signal 2011; 15:2605-41. [PMID: 21391902 DOI: 10.1089/ars.2010.3547] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A chronic inflammatory disease is a condition characterized by persistent inflammation. A number of human pathologies fall into this category, and a great deal of research has been conducted to learn more about their characteristics and underlying mechanisms. In many cases, a genetic component has been identified, but also external factors like food, smoke, or environmental pollutants can significantly contribute to worsen their symptoms. Accumulated evidence clearly shows that chronic inflammatory diseases are subjected to a redox control. Here, we shall review the identity, source, regulation, and biological activity of redox molecules, to put in a better perspective their key-role in cancer, diabetes, cardiovascular diseases, atherosclerosis, chronic obstructive pulmonary diseases, and inflammatory bowel diseases. In addition, the impact of redox species on autoimmune disorders (rheumatoid arthritis, systemic lupus erythematosus, psoriasis, and celiac disease) and neurodegenerative diseases (Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis) will be discussed, along with their potential therapeutic implications as novel drugs to combat chronic inflammatory disorders.
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Affiliation(s)
- Valerio Chiurchiù
- European Center for Brain Research/Santa Lucia Foundation, Rome, Italy
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310
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Antioxidant and anti-inflammatory effects of exercise in diabetic patients. EXPERIMENTAL DIABETES RESEARCH 2011; 2012:941868. [PMID: 22007193 PMCID: PMC3191828 DOI: 10.1155/2012/941868] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 07/15/2011] [Accepted: 07/17/2011] [Indexed: 02/06/2023]
Abstract
Diabetes is a chronic metabolic disease which is characterized by absolute or relative deficiencies in insulin secretion and/or insulin action. The key roles of oxidative stress and inflammation in the progression of vascular complications of this disease are well recognized. Accumulating epidemiologic evidence confirms that physical inactivity is an independent risk factor for insulin resistance and type II diabetes. This paper briefly reviews the pathophysiological pathways associated with oxidative stress and inflammation in diabetes mellitus and then discusses the impact of exercise on these systems. In this regard, we discuss exercise induced activation of cellular antioxidant systems through “nuclear factor erythroid 2-related factor.” We also discuss anti-inflammatory myokines, which are produced and released by contracting muscle fibers. Antiapoptotic, anti-inflammatory and chaperon effects of exercise-induced heat shock proteins are also reviewed.
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311
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Szalowska E, Dijkstra M, Elferink MGL, Weening D, de Vries M, Bruinenberg M, Hoek A, Roelofsen H, Groothuis GMM, Vonk RJ. Comparative analysis of the human hepatic and adipose tissue transcriptomes during LPS-induced inflammation leads to the identification of differential biological pathways and candidate biomarkers. BMC Med Genomics 2011; 4:71. [PMID: 21978410 PMCID: PMC3196688 DOI: 10.1186/1755-8794-4-71] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Accepted: 10/06/2011] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Insulin resistance (IR) is accompanied by chronic low grade systemic inflammation, obesity, and deregulation of total body energy homeostasis. We induced inflammation in adipose and liver tissues in vitro in order to mimic inflammation in vivo with the aim to identify tissue-specific processes implicated in IR and to find biomarkers indicative for tissue-specific IR. METHODS Human adipose and liver tissues were cultured in the absence or presence of LPS and DNA Microarray Technology was applied for their transcriptome analysis. Gene Ontology (GO), gene functional analysis, and prediction of genes encoding for secretome were performed using publicly available bioinformatics tools (DAVID, STRING, SecretomeP). The transcriptome data were validated by proteomics analysis of the inflamed adipose tissue secretome. RESULTS LPS treatment significantly affected 667 and 483 genes in adipose and liver tissues respectively. The GO analysis revealed that during inflammation adipose tissue, compared to liver tissue, had more significantly upregulated genes, GO terms, and functional clusters related to inflammation and angiogenesis. The secretome prediction led to identification of 399 and 236 genes in adipose and liver tissue respectively. The secretomes of both tissues shared 66 genes and the remaining genes were the differential candidate biomarkers indicative for inflamed adipose or liver tissue. The transcriptome data of the inflamed adipose tissue secretome showed excellent correlation with the proteomics data. CONCLUSIONS The higher number of altered proinflammatory genes, GO processes, and genes encoding for secretome during inflammation in adipose tissue compared to liver tissue, suggests that adipose tissue is the major organ contributing to the development of systemic inflammation observed in IR. The identified tissue-specific functional clusters and biomarkers might be used in a strategy for the development of tissue-targeted treatment of insulin resistance in patients.
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Affiliation(s)
- Ewa Szalowska
- Centre for Medical Biomics, University Medical Centre Groningen (UMCG), University of Groningen, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
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312
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Abstract
The number of people with diabetic kidney disease continues to increase worldwide despite current treatments. Of the pathophysiologic mechanisms that have been identified in the development and progression of diabetic nephropathy, oxidative stress (more accurately described as increased levels of reactive oxygen species; ROS) is of major importance. The increase in ROS is due to both increased production and to decreased and/or inadequate antioxidant function. To date, human clinical trials with antioxidants have not been shown to be effective. This is likely due, at least in part, to the lack of specificity of current agents. Recent research has determined both major sources of high glucose-induced cellular ROS production as well as high glucose-induced changes in antioxidant function. Treatments targeted at one or more of the specific diabetes-induced alterations in the regulation of ROS levels will likely lead to effective treatments that prevent the development and progression of diabetic kidney disease.
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Affiliation(s)
- Robert C Stanton
- Harvard Medical School, Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA.
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313
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Seet RCS, Lee CYJ, Lim ECH, Quek AML, Huang H, Huang SH, Looi WF, Long LH, Halliwell B. Oral zinc supplementation does not improve oxidative stress or vascular function in patients with type 2 diabetes with normal zinc levels. Atherosclerosis 2011; 219:231-9. [PMID: 21840002 DOI: 10.1016/j.atherosclerosis.2011.07.097] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Revised: 07/11/2011] [Accepted: 07/12/2011] [Indexed: 02/07/2023]
Abstract
OBJECTIVE There is considerable controversy about what constitutes optimal zinc intakes in patients with type 2 diabetes mellitus. Several studies suggest that higher zinc intakes improve vascular function and decrease oxidative damage. We aimed to assess the effects of zinc supplementation using a range of reliable biomarkers of oxidative damage and vascular function in patients with type 2 diabetes. METHODS Forty male type 2 diabetic patients were supplemented either with 240 mg/day of zinc as zinc gluconate (n=20) or with placebo (n=20) for 3 months. Blood and spot urine samples were taken at baseline, days 3 and 7, months 1, 2 and 3 during supplementation and 1 month after cessation. Serum zinc, reliable biomarkers of oxidative damage (F(2)-isoprostanes, neuroprostanes, cholesterol oxidation products, allantoin) as well as hydroxyeicosatetraenoic acid products and vascular-related indices (augmentation index, pulse wave velocity and aortic pressure) were measured. RESULTS Despite significantly higher levels of serum zinc in the treatment group, markers of oxidative damage, levels of hydroxyeicosatetraenoic acid products and vascular indices were unchanged by zinc supplementation during the four-month study period. CONCLUSION Improving the zinc status in patients with type 2 diabetes with normal zinc levels did not have any impact on oxidative damage and vascular function, and such supplementation may not be generally beneficial in these individuals.
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Affiliation(s)
- Raymond C S Seet
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
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314
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Abstract
The current status and likely future directions of complexes of V(V/IV), Cr(III), Mo(VI), W(VI), Zn(II), Cu(II), and Mn(III) as potential oral drugs against type 2 diabetes are reviewed. We propose a unified model of extra- and intracellular mechanisms of anti-diabetic efficacies of V(V/IV), Mo(VI), W(VI), and Cr(III), centred on high-oxidation-state oxido/peroxido species that inhibit protein tyrosine phosphatases (PTPs) involved in insulin signalling. The postulated oxidative mechanism of anti-diabetic activity of Cr(III) via carcinogenic Cr(VI/V) (which adds to safety concerns) is consistent with recent clinical trials on Cr(III) picolinate, where activity was apparent only in patients with poorly controlled diabetes (high oxidative stress), and the correlation between the anti-diabetic activities and ease of oxidation of Cr(III) supplements and their metabolites in vivo. Zn(II) and Cu(II) anti-diabetics act via different mechanisms and are unlikely to be used as specific anti-diabetics due to their diverse and unpredictable biological activities. Hence, future research directions are likely to centre on enhancing the bioavailability and selectivity of V(V/IV), Mo(VI), or W(VI) drugs. The strategy of potentiating circulating insulin with metal ions has distinct therapeutic advantages over interventions that stimulate the release of more insulin, or use insulin mimetics, because of many adverse side-effects of increased levels of insulin, including increased risks of cancer and cardiovascular diseases.
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Affiliation(s)
- Aviva Levina
- School of Chemistry, The University of Sydney, NSW, Australia
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315
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Ovadia H, Haim Y, Nov O, Almog O, Kovsan J, Bashan N, Benhar M, Rudich A. Increased adipocyte S-nitrosylation targets anti-lipolytic action of insulin: relevance to adipose tissue dysfunction in obesity. J Biol Chem 2011; 286:30433-30443. [PMID: 21724851 DOI: 10.1074/jbc.m111.235945] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Protein S-nitrosylation is a reversible protein modification implicated in both physiological and pathophysiological regulation of protein function. In obesity, skeletal muscle insulin resistance is associated with increased S-nitrosylation of insulin-signaling proteins. However, whether adipose tissue is similarly affected in obesity and, if so, what are the causes and functional consequences of increased S-nitrosylation in this tissue are unknown. Total protein S-nitrosylation was increased in intra-abdominal adipose tissue of obese humans and in high fat-fed or leptin-deficient ob/ob mice. Both the insulin receptor β-subunit and Akt were S-nitrosylated, correlating with body weight. Elevated protein and mRNA expression of inducible NO synthase and decreased protein levels of thioredoxin reductase were associated with increased adipose tissue S-nitrosylation. Cultured differentiated pre-adipocyte cell lines exposed to the NO donors S-nitrosoglutathione (GSNO) or S-nitroso-N-acetylpenicillamine exhibited diminished insulin-stimulated phosphorylation of Akt but not of GSK3 nor of insulin-stimulated glucose uptake. Yet the anti-lipolytic action of insulin was markedly impaired in both cultured adipocytes and in mice injected with GSNO prior to administration of insulin. In cells, impaired ability of insulin to diminish phosphorylated PKA substrates in response to isoproterenol suggested impaired insulin-induced activation of PDE3B. Consistently, increased S-nitrosylation of PDE3B was detected in adipose tissue of high fat-fed obese mice. Site-directed mutagenesis revealed that Cys-768 and Cys-1040, two putative sites for S-nitrosylation adjacent to the substrate-binding site of PDE3B, accounted for ∼50% of its GSNO-induced S-nitrosylation. Collectively, PDE3B and the anti-lipolytic action of insulin may constitute novel targets for increased S-nitrosylation of adipose tissue in obesity.
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Affiliation(s)
- Hilla Ovadia
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Yulia Haim
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Ori Nov
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Orna Almog
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Julia Kovsan
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Nava Bashan
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103
| | - Moran Benhar
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa 31096
| | - Assaf Rudich
- Department of Clinical Biochemistry, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva 84103; National Institute of Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva 84103, Israel.
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316
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Lademann J, Patzelt A, Schanzer S, Richter H, Meinke MC, Sterry W, Zastrow L, Doucet O, Vergou T, Darvin ME. Uptake of antioxidants by natural nutrition and supplementation: pros and cons from the dermatological point of view. Skin Pharmacol Physiol 2011; 24:269-73. [PMID: 21646825 DOI: 10.1159/000328725] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Accepted: 04/20/2011] [Indexed: 11/19/2022]
Abstract
The pros and cons of the systemic and topical application of antioxidant substances are a subject of intense discussion among experts, with resulting confusion for consumers and producers. The objective of the present article is to clarify the various uncertainties relating to the use of antioxidant substances in dermatology. Whereas inappropriate application of antioxidant substances (concerning their concentration and composition) might induce harmful effects, the consumer will definitively benefit from physiological concentrations and compositions of antioxidants. The most suitable method is the consumption of natural antioxidants in the form of fruit and vegetables, for example. In addition, the skin, which also accumulates antioxidant substances, may profit from a sufficient antioxidative level, as damage induced by sun radiation in addition to skin aging is reduced.
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Affiliation(s)
- J Lademann
- Center of Experimental and Applied Cutaneous Physiology, Department of Dermatology and Allergology, Charité - Universitätsmedizin Berlin, Germany
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317
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Abstract
Persistently elevated oxidative stress and inflammation precede or occur during the development of type 1 or type 2 diabetes mellitus and precipitate devastating complications. Given the rapidly increasing incidence of diabetes mellitus and obesity in the space of a few decades, new genetic mutations are unlikely to be the cause, instead pointing to environmental initiators. A hallmark of contemporary culture is a preference for thermally processed foods, replete with pro-oxidant advanced glycation endproducts (AGEs). These molecules are appetite-increasing and, thus, efficient enhancers of overnutrition (which promotes obesity) and oxidant overload (which promotes inflammation). Studies of genetic and nongenetic animal models of diabetes mellitus suggest that suppression of host defenses, under sustained pressure from food-derived AGEs, may potentially shift homeostasis towards a higher basal level of oxidative stress, inflammation and injury of both insulin-producing and insulin-responsive cells. This sequence promotes both types of diabetes mellitus. Reducing basal oxidative stress by AGE restriction in mice, without energy or nutrient change, reinstates host defenses, alleviates inflammation, prevents diabetes mellitus, vascular and renal complications and extends normal lifespan. Studies in healthy humans and in those with diabetes mellitus show that consumption of high amounts of food-related AGEs is a determinant of insulin resistance and inflammation and that AGE restriction improves both. This Review focuses on AGEs as novel initiators of oxidative stress that precedes, rather than results from, diabetes mellitus. Therapeutic gains from AGE restriction constitute a paradigm shift.
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Affiliation(s)
- Helen Vlassara
- Division of Experimental Diabetes and Aging, Brookdale Department of Geriatrics, Mount Sinai School of Medicine, New York, NY 10029, USA. helen.vlassara@ mssm.edu
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318
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Ge Y, Bruno M, Wallace K, Winnik W, Prasad RY. Proteome profiling reveals potential toxicity and detoxification pathways following exposure of BEAS-2B cells to engineered nanoparticle titanium dioxide. Proteomics 2011; 11:2406-22. [PMID: 21595037 DOI: 10.1002/pmic.201000741] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2010] [Revised: 03/01/2011] [Accepted: 03/08/2011] [Indexed: 12/22/2022]
Abstract
Oxidative stress is known to play important roles in engineered nanomaterial-induced cellular toxicity. However, the proteins and signaling pathways associated with the engineered nanomaterial-mediated oxidative stress and toxicity are largely unknown. To identify these toxicity pathways and networks that are associated with exposure to engineered nanomaterials, an integrated proteomic study was conducted using human bronchial epithelial cells, BEAS-2B and nanoscale titanium dioxide. Utilizing 2-DE and MS, we identified 46 proteins that were altered at protein expression levels. The protein changes detected by 2-DE/MS were verified by functional protein assays. These identified proteins include some key proteins involved in cellular stress response, metabolism, adhesion, cytoskeletal dynamics, cell growth, cell death, and cell signaling. The differentially expressed proteins were mapped using Ingenuity Pathway Analyses™ canonical pathways and Ingenuity Pathway Analyses tox lists to create protein-interacting networks and proteomic pathways. Twenty protein canonical pathways and tox lists were generated, and these pathways were compared to signaling pathways generated from genomic analyses of BEAS-2B cells treated with titanium dioxide. There was a significant overlap in the specific pathways and lists generated from the proteomic and the genomic data. In addition, we also analyzed the phosphorylation profiles of protein kinases in titanium dioxide-treated BEAS-2B cells for a better understanding of upstream signaling pathways in response to the titanium dioxide treatment and the induced oxidative stress. In summary, the present study provides the first protein-interacting network maps and novel insights into the biological responses and potential toxicity and detoxification pathways of titanium dioxide.
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Affiliation(s)
- Yue Ge
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, NC 27711, USA.
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319
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Hochmuth CE, Biteau B, Bohmann D, Jasper H. Redox regulation by Keap1 and Nrf2 controls intestinal stem cell proliferation in Drosophila. Cell Stem Cell 2011; 8:188-99. [PMID: 21295275 DOI: 10.1016/j.stem.2010.12.006] [Citation(s) in RCA: 276] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2010] [Revised: 10/05/2010] [Accepted: 11/19/2010] [Indexed: 01/08/2023]
Abstract
In Drosophila, intestinal stem cells (ISCs) respond to oxidative challenges and inflammation by increasing proliferation rates. This phenotype is part of a regenerative response, but can lead to hyperproliferation and epithelial degeneration in the aging animal. Here we show that Nrf2, a master regulator of the cellular redox state, specifically controls the proliferative activity of ISCs, promoting intestinal homeostasis. We find that Nrf2 is constitutively active in ISCs and that repression of Nrf2 by its negative regulator Keap1 is required for ISC proliferation. We further show that Nrf2 and Keap1 exert this function in ISCs by regulating the intracellular redox balance. Accordingly, loss of Nrf2 in ISCs causes accumulation of reactive oxygen species and accelerates age-related degeneration of the intestinal epithelium. Our findings establish Keap1 and Nrf2 as a critical redox management system that regulates stem cell function in high-turnover tissues.
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Affiliation(s)
- Christine E Hochmuth
- Department of Biology, University of Rochester, River Campus, Rochester, NY 14627, USA
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320
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Sim C, Denlinger DL. Catalase and superoxide dismutase-2 enhance survival and protect ovaries during overwintering diapause in the mosquito Culex pipiens. JOURNAL OF INSECT PHYSIOLOGY 2011; 57:628-34. [PMID: 21277308 PMCID: PMC3104096 DOI: 10.1016/j.jinsphys.2011.01.012] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Revised: 01/19/2011] [Accepted: 01/20/2011] [Indexed: 05/04/2023]
Abstract
Lifespan extension and stress resistance are two important features of diapause that are essential for successful overwintering. We present several lines of evidence suggesting that genes encoding two antioxidant enzymes, catalase and superoxide dismutase-2, are critical in generating these characteristics during diapause in overwintering adults of the mosquito Culex pipiens. Expression of both catalase and sod-2 was dramatically higher in young diapausing females than in their nondiapausing counterparts at the same age. Suppression of catalase, but not sod-2, resulted in increased damage to the ovaries, as evidenced by signs of apoptosis in ovarian follicle cells. Adult survival time was shortened when levels of either catalase or sod-2 were suppressed using RNAi. Together these results imply that these two antioxidants are particularly important in promoting survival in diapausing females, while elevation of catalase also contributes to protection of the ovaries. In addition, RNAi directed against forkhead transcription factor (foxo), a gene thought to be upstream of the genes encoding these antioxidants, resulted in suppression of both catalase and sod-2. The linkage with FOXO suggests that the genes encoding these two antioxidants are components of an important gene network regulated by this transcription factor.
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Affiliation(s)
- Cheolho Sim
- Department of Entomology, Ohio State University, 318 West 12th Avenue, Columbus, OH 43210, USA.
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321
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Yfanti C, Nielsen AR, Akerström T, Nielsen S, Rose AJ, Richter EA, Lykkesfeldt J, Fischer CP, Pedersen BK. Effect of antioxidant supplementation on insulin sensitivity in response to endurance exercise training. Am J Physiol Endocrinol Metab 2011; 300:E761-70. [PMID: 21325105 DOI: 10.1152/ajpendo.00207.2010] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
While production of reactive oxygen and nitrogen species (RONS) is associated with some of the beneficial adaptations to regular physical exercise, it is not established whether RONS play a role in the improved insulin-stimulated glucose uptake in skeletal muscle obtained by endurance training. To assess the effect of antioxidant supplementation during endurance training on insulin-stimulated glucose uptake, 21 young healthy (age 29 ± 1 y, BMI 25 ± 3 kg/m(2)) men were randomly assigned to either an antioxidant [AO; 500 mg vitamin C and 400 IU vitamin E (α-tocopherol) daily] or a placebo (PL) group that both underwent a supervised intense endurance-training program 5 times/wk for 12 wk. A 3-h euglycemic-hyperinsulinemic clamp, a maximal oxygen consumption (Vo(2max)) and maximal power output (P(max)) test, and body composition measurements (fat mass, fat-free mass) were performed before and after the training. Muscle biopsies were obtained for determination of the concentration and activity of proteins regulating glucose metabolism. Although plasma levels of vitamin C (P < 0.05) and α-tocopherol (P < 0.05) increased markedly in the AO group, insulin-stimulated glucose uptake increased similarly in both the AO (17.2%, P < 0.05) and the PL (18.9%, P < 0.05) group in response to training. Vo(2max) and P(max) also increased similarly in both groups (time effect, P < 0.0001 for both) as well as protein content of GLUT4, hexokinase II, and total Akt (time effect, P ≤ 0.05 for all). Our results indicate that administration of antioxidants during strenuous endurance training has no effect on the training-induced increase in insulin sensitivity in healthy individuals.
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Affiliation(s)
- Christina Yfanti
- Rigshospitalet, Centre of Inflammation and Metabolism, 7641, Blegdamsvej 9, DK-2100 Copenhagen, Denmark.
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322
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Pillon NJ, Vella RE, Soulère L, Becchi M, Lagarde M, Soulage CO. Structural and Functional Changes in Human Insulin Induced by the Lipid Peroxidation Byproducts 4-Hydroxy-2-nonenal and 4-Hydroxy-2-hexenal. Chem Res Toxicol 2011; 24:752-62. [DOI: 10.1021/tx200084d] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Nicolas J. Pillon
- Université de Lyon, F-69600, Oullins, France
- INSERM UMR 1060, CarMeN, F-69621, Villeurbanne, France
- INSA-Lyon, IMBL, F-69621, Villeurbanne, France
- INRA U1235, F-69600, Oullins, France
| | - Roxane E. Vella
- Université de Lyon, F-69600, Oullins, France
- INSERM UMR 1060, CarMeN, F-69621, Villeurbanne, France
- INSA-Lyon, IMBL, F-69621, Villeurbanne, France
- INRA U1235, F-69600, Oullins, France
| | - Laurent Soulère
- Université de Lyon, F-69600, Oullins, France
- Laboratoire de Chimie Organique et Bioorganique, INSA-LYON, CNRS UMR 5246, ICBMS, F-69622, Villeurbanne, France
| | - Michel Becchi
- Université de Lyon, F-69600, Oullins, France
- CNRS UMS 3444, CCMP, F-69367 Lyon, France
| | - Michel Lagarde
- Université de Lyon, F-69600, Oullins, France
- INSERM UMR 1060, CarMeN, F-69621, Villeurbanne, France
- INSA-Lyon, IMBL, F-69621, Villeurbanne, France
- INRA U1235, F-69600, Oullins, France
| | - Christophe O. Soulage
- Université de Lyon, F-69600, Oullins, France
- INSERM UMR 1060, CarMeN, F-69621, Villeurbanne, France
- INSA-Lyon, IMBL, F-69621, Villeurbanne, France
- INRA U1235, F-69600, Oullins, France
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323
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Yu Z, Shao W, Chiang Y, Foltz W, Zhang Z, Ling W, Fantus IG, Jin T. Oltipraz upregulates the nuclear factor (erythroid-derived 2)-like 2 [corrected](NRF2) antioxidant system and prevents insulin resistance and obesity induced by a high-fat diet in C57BL/6J mice. Diabetologia 2011; 54:922-34. [PMID: 21161163 DOI: 10.1007/s00125-010-2001-8] [Citation(s) in RCA: 138] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 11/03/2010] [Indexed: 12/23/2022]
Abstract
AIMS/HYPOTHESIS We investigated whether oltipraz, a nuclear respiratory factor 2 alpha subunit (NRF2) activator, improves insulin sensitivity and prevents the development of obesity in mice. METHODS C57BL/6J mice were fed with a low-fat diet (10% of energy as fat), a high-fat diet (HFD) (45% of energy as fat) or a HFD with oltipraz for 28 weeks. The effects of oltipraz on body weight, fat content, glucose disposal, insulin signalling, metabolic profiles and endogenous NRF2 functional status in the three groups of mice were investigated. RESULTS Oltipraz prevented or significantly attenuated the effect of HFD on glucose disposal, body weight and fat gain. Impairment of protein kinase B/Akt phosphorylation in this HFD-fed mouse model in response to intraperitoneal insulin injection was observed in adipose tissue, but not in the muscles, accompanied by inhibition of AMP-activated protein kinase signalling and activation of p70S6 kinase, as well as reduced GLUT4 content. These defects were attenuated by oltipraz administration. Nuclear content of NRF2 in adipose tissue was reduced by HFD feeding, associated with increased Keap1 mRNA expression and reduced production of haem oxygenase-1 and superoxide dismutase, increased protein oxidation, decreased plasma reduced:oxidised glutathione ratio and the appearance of macrophage marker F4/80. These defects were also restored by oltipraz. Finally, oltipraz attenuated HFD-induced inducible nitric oxide synthase overproduction. CONCLUSIONS/INTERPRETATION Impairment of the endogenous redox system is important in the development of obesity and insulin resistance in chronic HFD feeding. NRF2 activation represents a potential novel approach in the treatment and prevention of obesity and diabetes.
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Affiliation(s)
- Z Yu
- Guandong Provincial Key Laboratory of Food, Nutrition and Health, Department of Nutrition, Public Health Institute, Sun Yat-Sen University, Guangzhou, People's Republic of China
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324
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Burns TA, Westerman T, Nuovo GJ, Watts MR, Pettigrew A, Yin C, Belknap JK. Role of oxidative tissue injury in the pathophysiology of experimentally induced equine laminitis: a comparison of 2 models. J Vet Intern Med 2011; 25:540-8. [PMID: 21418321 DOI: 10.1111/j.1939-1676.2011.0706.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Oxidative stress reportedly plays a role in sepsis-induced organ dysfunction and failure in many species. In septic horses, laminae are targeted; evidence of laminar oxidative stress has been reported experimentally in the black walnut extract (BWE) model. Carbohydrate (CHO)-induced laminitis may be more similar to clinical sepsis-related laminitis than the BWE model in that animals with CHO-induced disease commonly develop laminar failure. The role of oxidative stress in the CHO model remains unknown. HYPOTHESIS/OBJECTIVES Markers of oxidative stress will be increased in laminae from horses with BWE- and CHO-induced laminitis. ANIMALS Banked laminar tissue from various time points from animals subjected to BWE (n = 15) and CHO (n = 20) protocols. METHODS Laminar 4-hydroxynonenal (4-HNE) and protein carbonyl content were evaluated by slot blot analysis. Laminar 3-nitrotyrosine (3-NT) immunohistochemistry was performed. RESULTS The number of laminar 3-NT (+) cells was increased at developmental and Obel grade 1 (OG1) time points in the BWE model (versus control [CON]; P= .013) and lower in OG1 tissues than CON in the CHO model (P = .04). No change in 4-HNE content was observed in the CHO model, and no increase in laminar protein carbonyl content was present in either model (P > .05). CONCLUSIONS AND CLINICAL IMPORTANCE These results do not support a prominent role for oxidative stress at examined time points in CHO-overload laminitis and support transient oxidative stress in the BWE model. Tissue oxidation does not appear to be a central early pathophysiologic event in CHO-associated laminitis.
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Affiliation(s)
- T A Burns
- Ohio State University College of Veterinary Medicine, Columbus, OH 43210, USA
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325
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de Keizer PLJ, Burgering BMT, Dansen TB. Forkhead box o as a sensor, mediator, and regulator of redox signaling. Antioxid Redox Signal 2011; 14:1093-106. [PMID: 20626320 DOI: 10.1089/ars.2010.3403] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The forkhead box O (FOXO) family of transcription factors regulates a variety of cellular programs, including cell cycle arrest, reactive oxygen species (ROS) scavenging, and apoptosis, and are of key importance in the decision over cell fate. In animal model systems it has been shown that FOXO is involved in the regulation of long lifespan. FOXO activity is tightly controlled by the insulin signaling pathway and by a multitude of ROS-induced posttranslational modifications. In the cell, ROS levels can be sensed by virtue of stimulatory and inhibitory oxidative modification of cysteine residues within proteins that control various signaling cascades. Recently, it was shown that cysteines in FOXO can also act as sensors of the local redox state. In this review we have outlined the cysteine-dependent redox switches that regulate both the insulin and ROS signaling pathways upstream of FOXO. Further, we describe how FOXO controls ROS levels by transcriptional regulation of a multilayered antioxidant system. Finally, we will discuss how cysteine-based redox signaling to FOXO could play a role in fine-tuning the optimal cellular response to ROS to control organismal lifespan.
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Affiliation(s)
- Peter L J de Keizer
- Department of Physiological Chemistry, Centre for Biomedical Genetics and Cancer Genomics Centre, University Medical Center Utrecht, Utrecht, The Netherlands
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326
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Surachetpong W, Pakpour N, Cheung KW, Luckhart S. Reactive oxygen species-dependent cell signaling regulates the mosquito immune response to Plasmodium falciparum. Antioxid Redox Signal 2011; 14:943-55. [PMID: 21126166 PMCID: PMC3042311 DOI: 10.1089/ars.2010.3401] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Reactive oxygen species (ROS) have been implicated in direct killing of pathogens, increased tissue damage, and regulation of immune signaling pathways in mammalian cells. Available research suggests that analogous phenomena affect the establishment of Plasmodium infection in Anopheles mosquitoes. We have previously shown that provision of human insulin in a blood meal leads to increased ROS levels in Anopheles stephensi. Here, we demonstrate that provision of human insulin significantly increased parasite development in the same mosquito host in a manner that was not consistent with ROS-induced parasite killing or parasite escape through damaged tissue. Rather, our studies demonstrate that ROS are important mediators of both the mitogen-activated protein kinase and phosphatidylinositol 3-kinase/Akt signaling branches of the mosquito insulin signaling cascade. Further, ROS alone can directly activate these signaling pathways and this activation is growth factor specific. Our data, therefore, highlight a novel role for ROS as signaling mediators in the mosquito innate immune response to Plasmodium parasites.
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Affiliation(s)
- Win Surachetpong
- Department of Medical Microbiology and Immunology, University of California, Davis, Davis, California 95616, USA
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327
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Kane DA, Lin CT, Anderson EJ, Kwak HB, Cox JH, Brophy PM, Hickner RC, Neufer PD, Cortright RN. Progesterone increases skeletal muscle mitochondrial H2O2 emission in nonmenopausal women. Am J Physiol Endocrinol Metab 2011; 300:E528-35. [PMID: 21189359 PMCID: PMC3064007 DOI: 10.1152/ajpendo.00389.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The luteal phase of the female menstrual cycle is associated with both 1) elevated serum progesterone (P4) and estradiol (E2), and 2) reduced insulin sensitivity. Recently, we demonstrated a link between skeletal muscle mitochondrial H(2)O(2) emission (mE(H2O2)) and insulin resistance. To determine whether serum levels of P4 and/or E(2) are related to mitochondrial function, mE(H2O2) and respiratory O(2) flux (Jo(2)) were measured in permeabilized myofibers from insulin-sensitive (IS, n = 24) and -resistant (IR, n = 8) nonmenopausal women (IR = HOMA-IR > 3.6). Succinate-supported mE(H2O2) was more than 50% greater in the IR vs. IS women (P < 0.05). Interestingly, serum P4 correlated positively with succinate-supported mE(H2O2) (r = 0. 53, P < 0.01). To determine whether P4 or E2 directly affect mitochondrial function, saponin-permeabilized vastus lateralis myofibers biopsied from five nonmenopausal women in the early follicular phase were incubated in P4 (60 nM), E2 (1.4 nM), or both. P4 alone inhibited state 3 Jo(2), supported by multisubstrate combination (P < 0.01). However, E2 alone or in combination with P4 had no effect on Jo(2). In contrast, during state 4 respiration, supported by succinate and glycerophosphate, mE(H2O2) was increased with P4 alone or in combination with E2 (P < 0.01). The results suggest that 1) P4 increases mE(H2O2) with or without E2; 2) P4 alone inhibits Jo(2) but not when E2 is present; and 3) P4 is related to the mE(H2O2) previously linked to skeletal muscle insulin resistance.
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Affiliation(s)
- Daniel A Kane
- The Human Performance Laboratory, East Carolina University, Greenville, NC 27858, USA.
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328
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Anju TR, Nandhu MS, Jes P, Paulose CS. Endocrine regulation of neonatal hypoxia: role of glucose, oxygen, and epinephrine supplementation. Fetal Pediatr Pathol 2011; 30:338-49. [PMID: 21846315 DOI: 10.3109/15513815.2011.587498] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Responses of the endocrine system are vital in revealing the mechanisms of respiratory activities. The present study focused on changes in insulin and triiodothyronine concentration in serum, its receptors in the hearts of hypoxic neonatal rats and glucose, oxygen, and epinephrine resuscitated groups. The insulin concentration was significantly increased with a significant upregulation of receptors in hypoxic neonates. Triiodothyronine content and its receptors were significantly decreased in serum and the hearts of hypoxic neonates. The change in hormonal levels is an adaptive modification of the endocrine system to encounter the stress. The effectiveness of glucose resuscitation to hypoxic neonates was also reported.
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Affiliation(s)
- T R Anju
- Department of Biotechnology, Cochin University of Science and Technology, Cochin, India
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329
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Verhaeghe J, van Bree R, Van Herck E. Oxidant balance markers at birth in relation to glycemic and acid-base parameters. Metabolism 2011; 60:71-7. [PMID: 20537667 DOI: 10.1016/j.metabol.2010.04.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 03/30/2010] [Accepted: 04/14/2010] [Indexed: 11/29/2022]
Abstract
In diabetic pregnancies, suboptimal glycemic control is a risk factor for fetal acidemia and stillbirth. We hypothesized that the diabetic intrauterine milieu (hyperglycemia, hyperinsulinemia, changes in acid-base status) might predispose to oxidative stress. We studied 70 newborns whose mothers had pregestational diabetes (58 with type 1 diabetes mellitus) and 71 control newborns from nondiabetic mothers. Protein carbonyls (PCs), malondialdehyde, and 8-hydroxy-2'deoxyguanosine were measured in umbilical vein plasma as a reflection of protein, lipid, and DNA oxidative damage, respectively; glutathione peroxidase-3 (GPx3), an important circulating antioxidant enzyme, was also assayed. Despite satisfactory glycemic control in the majority of diabetic mothers, their newborns showed higher birth weight and relative hyperglycemia, hyperinsulinemia, and respiratory acidemia. The oxidant balance marker concentrations were not different at the P < .05 level between the 2 groups, and there was no relationship to maternal hemoglobin A(₁C) levels in the diabetic group. However, in the entire sample, increasing glucose levels at birth were related to lower GPx3 and higher PC concentrations; and GPx3 and PC concentrations were inversely correlated. In addition, a depressed pH or larger base-deficit at birth was related to higher PC and 8-hydroxy-2'deoxyguanosine concentrations. In conclusion, oxidant balance markers at birth are not affected by maternal diabetes per se and its long-term glycemic control, yet some markers are acutely tuned to metabolic cues including glucose and the acid-base environment.
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Affiliation(s)
- Johan Verhaeghe
- Department of Obstetrics and Gynecology, Health Sciences Campus Gasthuisberg, Katholieke Universiteit Leuven, 3000 Leuven, Belgium.
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330
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Abstract
Oxidative Stress in Obesity and Metabolic Syndrome in Asian IndiansOxidative stress is associated with the individual components of metabolic syndrome and has been implicated in the development of complications of these metabolic disorders. In this study oxidative stress levels have been compared in obese Indians (a high-risk population for diabetes and cardiovascular disorders) with and without metabolic syndrome. 30 adult normotensive, normoglycemic obese subjects and 35 adults with metabolic syndrome of either sex with BMI >23 kg/m2were compared with 30 adult, healthy volunteers with BMI <23 kg/m2. Anthropometric parameters, blood pressure, biochemical parameters, hydroperoxides levels and total antioxidant capacity were estimated. The obese groups with and without metabolic syndrome had significantly increased anthropometric parameters like waist circumference and index of central obesity and aqueous phase hydroperoxides when compared with normal controls. The metabolic syndrome group also had significantly increased blood sugar levels, lipid profile and hydroperoxide levels when compared to obese or control groups. There was no alteration in the total antioxidant capacity in any of the groups. The Triglyceride/HDL-Cholesterol ratio (>3), a surrogate marker of insulin resistance, indicates insulin resistance in the metabolic syndrome group. The anthropometric profile, insulin resistance and oxidative stress seen in obesity are further elaborated in metabolic syndrome. Thus, the early identification of high-risk individuals based on anthropometric parameters, lipid profile, insulin resistance and indices of oxidative stress may help to prevent the development of complications of metabolic syndrome.
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331
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Sanz MN, Sánchez-Martín C, Detaille D, Vial G, Rigoulet M, El-Mir MY, Rodríguez-Villanueva G. Acute Mitochondrial Actions of Glitazones on the Liver: a Crucial Parameter for their Antidiabetic Properties. Cell Physiol Biochem 2011; 28:899-910. [DOI: 10.1159/000335804] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2011] [Indexed: 01/30/2023] Open
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332
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Sampson SR, Bucris E, Horovitz-Fried M, Parnas A, Kahana S, Abitbol G, Chetboun M, Rosenzweig T, Brodie C, Frankel S. Insulin increases H2O2-induced pancreatic beta cell death. Apoptosis 2010; 15:1165-76. [PMID: 20544287 DOI: 10.1007/s10495-010-0517-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Insulin resistance results, in part, from impaired insulin signaling in insulin target tissues. Consequently, increased levels of insulin are necessary to control plasma glucose levels. The effects of elevated insulin levels on pancreatic beta (β) cell function, however, are unclear. In this study, we investigated the possibility that insulin may influence survival of pancreatic β cells. Studies were conducted on RINm, RINm5F and Min-6 pancreatic β-cells. Cell death was induced by treatment with H(2)O(2), and was estimated by measurements of LDH levels, viability assay (Cell-Titer Blue), propidium iodide staining and FACS analysis, and mitochondrial membrane potential (JC-1). In addition, levels of cleaved caspase-3 and caspase activity were determined. Treatment with H(2)O(2) increased cell death; this effect was increased by simultaneous treatment of cells with insulin. Insulin treatment alone caused a slight increase in cell death. Inhibition of caspase-3 reduced the effect of insulin to increase H(2)O(2)-induced cell death. Insulin increased ROS production by pancreatic β cells and increased the effect of H(2)O(2). These effects were increased by inhibition of IR signaling, indicative of an effect independent of the IR cascade. We conclude that elevated levels of insulin may act to exacerbate cell death induced by H(2)O(2) and, perhaps, other inducers of apoptosis.
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Affiliation(s)
- S R Sampson
- Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
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333
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Lee HY, Choi CS, Birkenfeld AL, Alves TC, Jornayvaz FR, Jurczak MJ, Zhang D, Woo DK, Shadel GS, Ladiges W, Rabinovitch PS, Santos JH, Petersen KF, Samuel VT, Shulman GI. Targeted expression of catalase to mitochondria prevents age-associated reductions in mitochondrial function and insulin resistance. Cell Metab 2010; 12:668-74. [PMID: 21109199 PMCID: PMC3013349 DOI: 10.1016/j.cmet.2010.11.004] [Citation(s) in RCA: 250] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/31/2010] [Accepted: 10/01/2010] [Indexed: 01/07/2023]
Abstract
Aging-associated muscle insulin resistance has been hypothesized to be due to decreased mitochondrial function, secondary to cumulative free radical damage, leading to increased intramyocellular lipid content. To directly test this hypothesis, we examined both in vivo and in vitro mitochondrial function, intramyocellular lipid content, and insulin action in lean healthy mice with targeted overexpression of the human catalase gene to mitochondria (MCAT mice). Here, we show that MCAT mice are protected from age-induced decrease in muscle mitochondrial function (∼30%), energy metabolism (∼7%), and lipid-induced muscle insulin resistance. This protection from age-induced reduction in mitochondrial function was associated with reduced mitochondrial oxidative damage, preserved mitochondrial respiration and muscle ATP synthesis, and AMP-activated protein kinase-induced mitochondrial biogenesis. Taken together, these data suggest that the preserved mitochondrial function maintained by reducing mitochondrial oxidative damage may prevent age-associated whole-body energy imbalance and muscle insulin resistance.
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Affiliation(s)
- Hui-Young Lee
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06510, USA
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334
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Zhang Y, Zhang HM, Shi Y, Lustgarten M, Li Y, Qi W, Zhang BX, Van Remmen H. Loss of manganese superoxide dismutase leads to abnormal growth and signal transduction in mouse embryonic fibroblasts. Free Radic Biol Med 2010; 49:1255-62. [PMID: 20638473 PMCID: PMC3418666 DOI: 10.1016/j.freeradbiomed.2010.07.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/18/2010] [Accepted: 07/09/2010] [Indexed: 10/19/2022]
Abstract
Manganese superoxide dismutase (MnSOD) in the mitochondria plays an important role in cellular defense against oxidative damage. Homozygous MnSOD knockout (Sod2(-/-)) mice are neonatal lethal, indicating the essential role of MnSOD in early development. To investigate the potential cellular abnormalities underlying the aborted development of Sod2(-/-) mice, we examined the growth of isolated mouse embryonic fibroblasts (MEFs) from Sod2(-/-) mice. We found that the proliferation of Sod2(-/-) MEFs was significantly decreased compared with wild-type MEFs despite the absence of morphological differences. The Sod2(-/-) MEFs produced less cellular ATP, had lower O(2) consumption, generated more superoxide, and expressed less Prdx3 protein. Furthermore, the loss of MnSOD dramatically altered several markers involved in cell proliferation and growth, including decreased growth stimulatory function of mTOR signaling and enhanced growth inhibitory function of GSK-3β signaling. Interestingly, the G-protein-coupled receptor-mediated intracellular Ca(2+) signal transduction was also severely suppressed in Sod2(-/-) MEFs. Finally, the ratio of microtubule-associated protein light chain 3 (LC3)-II/LC3-I, an index of autophagic activity, was increased in Sod2(-/-) MEFs, consistent with a reduction in mTOR signal transduction. These data demonstrate that MnSOD deficiency results in alterations in several key signaling pathways, which may contribute to the lethal phenotype of Sod2(-/-) mice.
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Affiliation(s)
- Yiqiang Zhang
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Hong-Mei Zhang
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Yun Shi
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Michael Lustgarten
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Yan Li
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Wenbo Qi
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Bin-Xian Zhang
- Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
| | - Holly Van Remmen
- Department of Physiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- Barshop Institute for Longevity and Aging Studies, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229
- South Texas Veterans Health Care System, San Antonio, Texas 78229
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335
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Manolopoulos KN, Klotz LO, Korsten P, Bornstein SR, Barthel A. Linking Alzheimer's disease to insulin resistance: the FoxO response to oxidative stress. Mol Psychiatry 2010; 15:1046-52. [PMID: 20966918 DOI: 10.1038/mp.2010.17] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Oxidative stress is an important determinant not only in the pathogenesis of Alzheimer's disease (AD), but also in insulin resistance (InsRes) and diabetic complications. Forkhead box class O (FoxO) transcription factors are involved in both insulin action and the cellular response to oxidative stress, thereby providing a potential integrative link between AD and InsRes. For example, the expression of intra- and extracellular antioxidant enzymes, such as manganese-superoxide dismutase and selenoprotein P, is regulated by FoxO proteins, as is the expression of important hepatic enzymes of gluconeogenesis. Here, we review the molecular mechanisms involved in the pathogenesis of AD and InsRes and discuss the function of FoxO proteins in these processes. Both InsRes and oxidative stress may promote the transcriptional activity of FoxO proteins, resulting in hyperglycaemia and a further increased production of reactive oxygen species (ROS). The consecutive activation of c-Jun N-terminal kinases and inhibition of Wingless (Wnt) signalling may result in the formation of β-amyloid plaques and τ protein phosphorylation. Wnt inhibition may also result in a sustained activation of FoxO proteins with induction of apoptosis and neuronal loss, thereby completing a vicious circle from oxidative stress, InsRes and hyperglycaemia back to the formation of ROS and consecutive neurodegeneration. In view of their central function in this model, FoxO proteins may provide a potential molecular target for the treatment of both InsRes and AD.
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Affiliation(s)
- K N Manolopoulos
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital Oxford, Oxford, UK
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336
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Afanas'ev I. Signaling of reactive oxygen and nitrogen species in Diabetes mellitus. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2010; 3:361-73. [PMID: 21311214 PMCID: PMC3154046 DOI: 10.4161/oxim.3.6.14415] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/26/2010] [Accepted: 12/06/2010] [Indexed: 02/07/2023]
Abstract
Disorder of physiological signaling functions of reactive oxygen species (ROS) superoxide and hydrogen peroxide and reactive nitrogen species (RNS) nitric oxide and peroxynitrite is an important feature of diabetes mellitus type 1 and type 2. It is now known that hyperglycemic conditions of cells are associated with the enhanced levels of ROS mainly generated by mitochondria and NADPH oxidase. It has been established that ROS stimulate many enzymatic cascades under normal physiological conditions, but hyperglycemia causes ROS overproduction and the deregulation of ROS signaling pathways initiating the development of diabetes mellitus. On the other hand the deregulation of RNS signaling leads basically to a decrease in NO formation with subsequent damaging disorders. In the present work we will consider the pathological changes of ROS and RNS signaling in enzyme/gene regulated processes catalyzed by protein kinases C and B (Akt/B), phosphatidylinositol 3'-kinase (PI3-kinase), extracellular signal-regulated kinase 1/2 (ERK1/2), and some others. Furthermore we will discuss a particularly important role of several ROS-regulated genes and adapter proteins such as the p66shc, FOXO3a, and Sirt2. The effects of low and high ROS levels in diabetes will be also considered. Thus the regulation of damaging ROS levels in diabetes by antioxidants and free radical scavengers must be one of promising treatment of this disease, however, because of the inability of traditional antioxidative vitamin E and C to interact with superoxide and hydrogen peroxide, new free radical scavengers such as flavonoids, quinones and synthetic mimetics of superoxide dismutase (SOD) should be intensively studied.
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337
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Postprandial metabolic events and fruit-derived phenolics: a review of the science. Br J Nutr 2010; 104 Suppl 3:S1-14. [DOI: 10.1017/s0007114510003909] [Citation(s) in RCA: 136] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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338
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Li M, Zhao L, Liu J, Liu A, Jia C, Ma D, Jiang Y, Bai X. Multi-mechanisms are involved in reactive oxygen species regulation of mTORC1 signaling. Cell Signal 2010; 22:1469-76. [DOI: 10.1016/j.cellsig.2010.05.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Accepted: 05/26/2010] [Indexed: 01/23/2023]
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339
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Quantitative structure–activity relationship for 4-hydroxy-2-alkenal induced cytotoxicity in L6 muscle cells. Chem Biol Interact 2010; 188:171-80. [DOI: 10.1016/j.cbi.2010.06.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 06/23/2010] [Accepted: 06/30/2010] [Indexed: 11/18/2022]
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340
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Corby-Harris V, Drexler A, Watkins de Jong L, Antonova Y, Pakpour N, Ziegler R, Ramberg F, Lewis EE, Brown JM, Luckhart S, Riehle MA. Activation of Akt signaling reduces the prevalence and intensity of malaria parasite infection and lifespan in Anopheles stephensi mosquitoes. PLoS Pathog 2010; 6:e1001003. [PMID: 20664791 PMCID: PMC2904800 DOI: 10.1371/journal.ppat.1001003] [Citation(s) in RCA: 132] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 06/16/2010] [Indexed: 12/14/2022] Open
Abstract
Malaria (Plasmodium spp.) kills nearly one million people annually and this number will likely increase as drug and insecticide resistance reduces the effectiveness of current control strategies. The most important human malaria parasite, Plasmodium falciparum, undergoes a complex developmental cycle in the mosquito that takes approximately two weeks and begins with the invasion of the mosquito midgut. Here, we demonstrate that increased Akt signaling in the mosquito midgut disrupts parasite development and concurrently reduces the duration that mosquitoes are infective to humans. Specifically, we found that increased Akt signaling in the midgut of heterozygous Anopheles stephensi reduced the number of infected mosquitoes by 60-99%. Of those mosquitoes that were infected, we observed a 75-99% reduction in parasite load. In homozygous mosquitoes with increased Akt signaling parasite infection was completely blocked. The increase in midgut-specific Akt signaling also led to an 18-20% reduction in the average mosquito lifespan. Thus, activation of Akt signaling reduced the number of infected mosquitoes, the number of malaria parasites per infected mosquito, and the duration of mosquito infectivity.
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Affiliation(s)
- Vanessa Corby-Harris
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Anna Drexler
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Laurel Watkins de Jong
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Yevgeniya Antonova
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Nazzy Pakpour
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Rolf Ziegler
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Frank Ramberg
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Edwin E. Lewis
- Department of Entomology, University of California – Davis, Davis, California, United States of America
- Department of Nematology, University of California – Davis, Davis, California, United States of America
| | - Jessica M. Brown
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
| | - Shirley Luckhart
- Medical Microbiology and Immunology, University of California – Davis, Davis, California, United States of America
| | - Michael A. Riehle
- Department of Entomology, University of Arizona, Tucson, Arizona, United States of America
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Abstract
PURPOSE OF REVIEW Recent evidence suggests that oxidative stress is a cornerstone of the metabolic mechanisms by which overfeeding leads to insulin resistance. This review is an update of the most recent arguments in favor of this theory and of the possible role of antioxidants. RECENT FINDINGS Reactive oxidative species (ROS) are produced by multiple pathways within the cell and are essential for many cellular functions. ROS production is balanced by enzymatic and nonenzymatic antioxidant systems. The perturbation of the pro-oxidant/antioxidant balance can lead to increased oxidative damage of macromolecules, a phenomenon known as 'oxidative stress'. ROS are involved both in insulin signal transduction and in insulin resistance when produced in excess. Overfeeding, saturated fatty acids, and obesity play a key role in the excessive production of ROS. However, a diet rich in fruits and vegetables, and therefore antioxidants, has demonstrated beneficial effects against oxidative damages and insulin resistance. SUMMARY Experimental data are in favor of a beneficial role of antioxidants in glucose metabolism, but clinical data in humans are more controversial. Even if a diet rich in fruits and vegetables could provide an optimal mix of antioxidants, it remains unclear whether supplementation with antioxidants alone can reproduce the same effect.
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Affiliation(s)
- Catherine Bisbal
- INSERM, ERI25, Muscle and Pathologies, Université Montpellier I, Montpellier, France
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342
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Fujita Y, Hosokawa M, Fujimoto S, Mukai E, Abudukadier A, Obara A, Ogura M, Nakamura Y, Toyoda K, Nagashima K, Seino Y, Inagaki N. Metformin suppresses hepatic gluconeogenesis and lowers fasting blood glucose levels through reactive nitrogen species in mice. Diabetologia 2010; 53:1472-81. [PMID: 20349346 DOI: 10.1007/s00125-010-1729-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2010] [Accepted: 02/24/2010] [Indexed: 02/08/2023]
Abstract
AIMS/HYPOTHESIS Metformin, the major target of which is liver, is commonly used to treat type 2 diabetes. Although metformin activates AMP-activated protein kinase (AMPK) in hepatocytes, the mechanism of activation is still not well known. To investigate AMPK activation by metformin in liver, we examined the role of reactive nitrogen species (RNS) in suppression of hepatic gluconeogenesis. METHODS To determine RNS, we performed fluorescence examination and immunocytochemical staining in mouse hepatocytes. Since metformin is a mild mitochondrial complex I inhibitor, we compared its effects on suppression of gluconeogenesis, AMPK activation and generation of the RNS peroxynitrite (ONOO(-)) with those of rotenone, a representative complex I inhibitor. To determine whether endogenous nitric oxide production is required for ONOO(-) generation and metformin action, we used mice lacking endothelial nitric oxide synthase (eNOS). RESULTS Metformin and rotenone significantly decreased gluconeogenesis and increased phosphorylation of AMPK in wild-type mouse hepatocytes. However, unlike rotenone, metformin did not increase the AMP/ATP ratio. It did, however, increase ONOO(-) generation, whereas rotenone did not. Exposure of eNOS-deficient hepatocytes to metformin did not suppress gluconeogenesis, activate AMPK or increase ONOO(-) generation. Furthermore, metformin lowered fasting blood glucose levels in wild-type diabetic mice, but not in eNOS-deficient diabetic mice. CONCLUSIONS/INTERPRETATION Activation of AMPK by metformin is dependent on ONOO(-). For metformin action in liver, intra-hepatocellular eNOS is required.
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Affiliation(s)
- Y Fujita
- Department of Diabetes and Clinical Nutrition, Graduate School of Medicine, Kyoto University, 54 Shogoin, Kawahara-cho, Sakyo-ku, Kyoto, 606-8507, Japan
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343
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Kewalramani G, Bilan PJ, Klip A. Muscle insulin resistance: assault by lipids, cytokines and local macrophages. Curr Opin Clin Nutr Metab Care 2010; 13:382-90. [PMID: 20495453 DOI: 10.1097/mco.0b013e32833aabd9] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE OF REVIEW The present review outlines possible mechanisms by which high fatty acids, associated with high-fat diet and obesity, impose insulin resistance on glucose uptake into skeletal muscle. RECENT FINDINGS It is well established that muscle insulin resistance arises in conditions of high-fatty acid availability, and correlates with accumulation of triglycerides within skeletal muscle fibres. However, it is debated whether triglycerides or other lipid metabolites such as diacylglycerols and ceramides are directly responsible. These lipid metabolites can activate serine kinases that impair insulin signalling. Accumulation of acylcarnitines and reactive oxygen species could be additional causative agents of insulin resistance. Further, the precise defects in insulin signalling in muscle caused by high intramuscular lipid (i.e. lipotoxicity) remain unclear. In parallel, proinflammatory activation within the adipose tissue of obese and high-fat fed animals or humans causes muscle insulin resistance, and is ascribed to circulating inflammatory cytokines. Recent evidence also shows proinflammatory macrophages infiltrating muscle tissue and/or intermuscular adipose tissue, and there is growing evidence that fatty acids trigger macrophages to secrete factors that directly impair insulin actions. These factors are postulated to activate stress-signalling pathways in muscle that act on the same insulin-signalling components affected by lipotoxicity. SUMMARY Altered intramuscular lipid metabolism, circulating cytokines, and inflammatory macrophage infiltration of muscle tissue have been recently linked to muscle insulin resistance provoked by fatty acids. Each is analysed separately in this review, but they may act simultaneously and synergistically to render skeletal muscle insulin-resistant.
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344
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Abstract
The unique chemistry of oxygen has been both a resource and threat for life on Earth for at least the last 2.4 billion years. Reduction of oxygen to water allows extraction of more metabolic energy from organic fuels than is possible through anaerobic glycolysis. On the other hand, partially reduced oxygen can react indiscriminately with biomolecules to cause genetic damage, disease, and even death. Organisms in all three superkingdoms of life have developed elaborate mechanisms to protect against such oxidative damage and to exploit reactive oxygen species as sensors and signals in myriad processes. The sulfur amino acids, cysteine and methionine, are the main targets of reactive oxygen species in proteins. Oxidative modifications to cysteine and methionine can have profound effects on a protein's activity, structure, stability, and subcellular localization. Non-reversible oxidative modifications (oxidative damage) may contribute to molecular, cellular, and organismal aging and serve as signals for repair, removal, or programmed cell death. Reversible oxidation events can function as transient signals of physiological status, extracellular environment, nutrient availability, metabolic state, cell cycle phase, immune function, or sensory stimuli. Because of its chemical similarity to sulfur and stronger nucleophilicity and acidity, selenium is an extremely efficient catalyst of reactions between sulfur and oxygen. Most of the biological activity of selenium is due to selenoproteins containing selenocysteine, the 21st genetically encoded protein amino acid. The most abundant selenoproteins in mammals are the glutathione peroxidases (five to six genes) that reduce hydrogen peroxide and lipid hydroperoxides at the expense of glutathione and serve to limit the strength and duration of reactive oxygen signals. Thioredoxin reductases (three genes) use nicotinamide adenine dinucleotide phosphate to reduce oxidized thioredoxin and its homologs, which regulate a plethora of redox signaling events. Methionine sulfoxide reductase B1 reduces methionine sulfoxide back to methionine using thioredoxin as a reductant. Several selenoproteins in the endoplasmic reticulum are involved in the regulation of protein disulfide formation and unfolded protein response signaling, although their precise biological activities have not been determined. The most widely distributed selenoprotein family in Nature is represented by the highly conserved thioredoxin-like selenoprotein W and its homologs that have not yet been assigned specific biological functions. Recent evidence suggests selenoprotein W and the six other small thioredoxin-like mammalian selenoproteins may serve to transduce hydrogen peroxide signals into regulatory disulfide bonds in specific target proteins.
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Affiliation(s)
- Wayne Chris Hawkes
- USDA Agricultural Research Service, Western Human Nutrition Research Center, University of California at Davis, Davis, USA
| | - Zeynep Alkan
- USDA Agricultural Research Service, Western Human Nutrition Research Center, University of California at Davis, Davis, USA
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345
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Anti-diabetic effects of lemon balm (Melissa officinalis) essential oil on glucose- and lipid-regulating enzymes in type 2 diabetic mice. Br J Nutr 2010; 104:180-8. [DOI: 10.1017/s0007114510001765] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The antioxidant activity of lemon balm (Melissa officinalis) essential oil (LBEO) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and its hypoglycaemic effect in db/db mice were investigated. LBEO scavenged 97 % of DPPH radicals at a 270-fold dilution. Mice administered LBEO (0·015 mg/d) for 6 weeks showed significantly reduced blood glucose (65 %; P < 0·05) and TAG concentrations, improved glucose tolerance, as assessed by an oral glucose tolerance test, and significantly higher serum insulin levels, compared with the control group. The hypoglycaemic mechanism of LBEO was further explored via gene and protein expression analyses using RT-PCR and Western blotting, respectively. Among all glucose metabolism-related genes studied, hepatic glucokinase and GLUT4, as well as adipocyte GLUT4, PPAR-γ, PPAR-α and SREBP-1c expression, were significantly up-regulated, whereas glucose-6-phosphatase and phosphoenolpyruvate carboxykinase expression was down-regulated in the livers of the LBEO group. The results further suggest that LBEO administered at low concentrations is an efficient hypoglycaemic agent, probably due to enhanced glucose uptake and metabolism in the liver and adipose tissue and the inhibition of gluconeogenesis in the liver.
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346
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Pitocco D, Zaccardi F, Di Stasio E, Romitelli F, Santini SA, Zuppi C, Ghirlanda G. Oxidative stress, nitric oxide, and diabetes. Rev Diabet Stud 2010; 7:15-25. [PMID: 20703435 DOI: 10.1900/rds.2010.7.15] [Citation(s) in RCA: 188] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In the recent decades, oxidative stress has become focus of interest in most biomedical disciplines and many types of clinical research. Increasing evidence from research on several diseases show that oxidative stress is associated with the pathogenesis of diabetes, obesity, cancer, ageing, inflammation, neurodegenerative disorders, hypertension, apoptosis, cardiovascular diseases, and heart failure. Based on this research, the emerging concept is that oxidative stress is the "final common pathway", through which risk factors of several diseases exert their deleterious effects. Oxidative stress causes a complex dysregulation of cell metabolism and cell-cell homeostasis. In this review, we discuss the role of oxidative stress in the pathogenesis of insulin resistance and beta-cell dysfunction. These are the two most relevant mechanisms in the pathophysiology of type 2 diabetes, and in the pathogenesis of diabetic vascular complications, the leading cause of death in diabetic patients.
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Affiliation(s)
- Dario Pitocco
- Institute of Internal Medicine, Catholic University of Rome, Largo Agostino Gemelli 8, 00168 Rome, Italy.
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347
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Park CH, Noh JS, Tanaka T, Yokozawa T. Effects of morroniside isolated from Corni Fructus on renal lipids and inflammation in type 2 diabetic mice. J Pharm Pharmacol 2010; 62:374-80. [PMID: 20487222 DOI: 10.1211/jpp.62.03.0013] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Abstract
Objectives
The effects of morroniside isolated from Corni Fructus on renal lipids and inflammation provoked by hyperglycaemia were investigated using type 2 diabetic mice.
Methods
Morroniside was administered orally to db/db mice at 20 or 100 mg/kg daily for 8 weeks, and its effects were compared with those in vehicle-treated db/db and m/m (non-diabetic) mice. Serum and renal biochemical factors and protein expression related to lipid homeostasis and inflammation were measured.
Key findings
Morroniside produced significant dose-dependent reductions in serum triglyceride and renal glucose and lipid levels. Morroniside altered the abnormal protein expression of sterol regulatory element binding proteins (SREBP-1 and SREBP-2). In addition, the formation of reactive oxygen species and lipid peroxidation were inhibited in the morroniside-treated db/db mouse group, and the ratio of reduced glutathione to the oxidised form was significantly elevated. These results suggest that morroniside alleviated oxidative stress in the kidneys of db/db mice. Furthermore, 100 mg/kg morroniside down-regulated the expression of nuclear factor-κBp65, cyclooxygenase-2 and inducible nitric oxide synthase augmented in db/db mice.
Conclusions
Morroniside may inhibit abnormal lipid metabolism and inflammation due to reactive oxygen species in the kidneys in type 2 diabetes.
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Affiliation(s)
- Chan Hum Park
- Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Jeong Sook Noh
- Institute of Natural Medicine, University of Toyama, Toyama, Japan
| | - Takashi Tanaka
- Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Takako Yokozawa
- Institute of Natural Medicine, University of Toyama, Toyama, Japan
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348
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Cai W, Torreggiani M, Zhu L, Chen X, He JC, Striker GE, Vlassara H. AGER1 regulates endothelial cell NADPH oxidase-dependent oxidant stress via PKC-delta: implications for vascular disease. Am J Physiol Cell Physiol 2010; 298:C624-34. [PMID: 19955485 PMCID: PMC2838573 DOI: 10.1152/ajpcell.00463.2009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2009] [Accepted: 11/30/2009] [Indexed: 12/29/2022]
Abstract
Advanced glycated end-product receptor 1 (AGER1) protects against vascular disease promoted by oxidants, such as advanced glycated end products (AGEs), via inhibition of reactive oxygen species (ROS). However, the specific AGEs, sources, and pathways involved remain undefined. The mechanism of cellular NADPH oxidase (NOX)-dependent ROS generation by defined AGEs, N(epsilon)-carboxymethyl-lysine- and methylglyoxal (MG)-modified BSA, was assessed in AGER1 overexpressing (AGER1(+) EC) or knockdown (sh-mRNA-AGER1(+) EC) human aortic endothelial (EC) and ECV304 cells, and aortic segments from old (18 mo) C57BL6-F(2) mice, propagated on low-AGE diet (LAGE), or LAGE supplemented with MG (LAGE+MG). Wild-type EC and sh-mRNA-AGER1(+) EC, but not AGER1(+) EC, had high NOX p47(phox) and gp91(phox) activity, superoxide anions, and NF-kappaB p65 nuclear translocation in response to MG and N(epsilon)-carboxymethyl-lysine. These events involved epidermal growth factor receptor-dependent PKC-delta redox-sensitive Tyr-311 and Tyr-332 phosphorylation and were suppressed in AGER1(+) ECs and enhanced in sh-mRNA-AGER1(+) ECs. Aortic ROS, PKC-delta Tyr-311, and Tyr-332 phosphorylation, NOX expression, and nuclear p65 in older LAGE+MG mice were significantly increased above that in age-matched LAGE mice, which had higher levels of AGER1. In conclusion, circulating AGEs induce NADPH-dependent ROS generation in vascular aging in both in vitro and in vivo models. Furthermore, AGER1 provides protection against AGE-induced ROS generation via NADPH.
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Affiliation(s)
- Weijing Cai
- Division of Experimental Diabetes and Aging, Mount Sinai School of Medicine, Box 1640, One Gustave Levy Place, New York, NY 10029, USA
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349
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Kassan M, Montero MJ, Sevilla MA. In vitro antioxidant activity of pravastatin provides vascular protection. Eur J Pharmacol 2010; 630:107-11. [DOI: 10.1016/j.ejphar.2009.12.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/24/2009] [Accepted: 12/15/2009] [Indexed: 02/07/2023]
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350
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Samocha-Bonet D, Heilbronn LK, Lichtenberg D, Campbell LV. Does skeletal muscle oxidative stress initiate insulin resistance in genetically predisposed individuals? Trends Endocrinol Metab 2010; 21:83-8. [PMID: 19854062 DOI: 10.1016/j.tem.2009.09.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Revised: 09/26/2009] [Accepted: 09/29/2009] [Indexed: 01/06/2023]
Abstract
Reactive oxygen species (ROS) are postulated to be a common trigger of insulin resistance. For example, treatment of adipocytes with either tumor-necrosis factor-alpha or dexamethasone increases ROS before impairing glucose uptake. Similarly, treatment with mitochondria-specific antioxidants preserves insulin sensitivity in animal models of insulin resistance. However, it remains unclear whether ROS contribute to insulin resistance in humans. First-degree relatives (FDRs) of type 2 diabetes subjects are at increased risk of developing insulin resistance and type 2 diabetes. Here we review the documented metabolic impairments in FDRs that could contribute to insulin resistance via increased oxidative stress. We propose that lipotoxic intermediates and lipid peroxides in skeletal muscle interfere with insulin signaling and might cause insulin resistance in these 'at risk' individuals.
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Affiliation(s)
- Dorit Samocha-Bonet
- Diabetes and Obesity Research Program, Garvan Institute of Medical Research, 384 Victoria Street, Darlinghurst, NSW 2010, Australia.
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