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Mey JT, Vandagmansar B, Dantas WS, Belmont KP, Axelrod CL, Kirwan JP. Ketogenic propensity is differentially related to lipid-induced hepatic and peripheral insulin resistance. Acta Physiol (Oxf) 2023; 239:e14054. [PMID: 37840478 DOI: 10.1111/apha.14054] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 09/11/2023] [Accepted: 09/26/2023] [Indexed: 10/17/2023]
Abstract
AIM Determine the ketogenic response (β-hydroxybutyrate, a surrogate of hepatic ketogenesis) to a controlled lipid overload in humans. METHODS In total, nineteen young, healthy adults (age: 28.4 ± 1.7 years; BMI: 22.7 ± 0.3 kg/m2 ) received either a 12 h overnight lipid infusion or saline in a randomized, crossover design. Plasma ketones and inflammatory markers were quantified by colorimetric and multiplex assays. Hepatic and peripheral insulin sensitivity was assessed by the hyperinsulinemic-euglycemic clamp. Skeletal muscle biopsies were obtained to quantify gene expression related to ketone body metabolism and inflammation. RESULTS By design, the lipid overload-induced hepatic (50%, p < 0.001) and peripheral insulin resistance (73%, p < 0.01) in healthy adults. Ketones increased with hyperlipidemia and were subsequently reduced with hyperinsulinemia during the clamp procedure (Saline: Basal = 0.22 mM, Insulin = 0.07 mM; Lipid: Basal = 0.78 mM, Insulin = 0.51 mM; 2-way ANOVA: Lipid p < 0.001, Insulin p < 0.001, Interaction p = 0.07). In the saline control condition, ketones did not correlate with hepatic or peripheral insulin sensitivity. Conversely, in the lipid condition, ketones were positively correlated with hepatic insulin sensitivity (r = 0.59, p < 0.01), but inversely related to peripheral insulin sensitivity (r = -0.64, p < 0.01). Hyperlipidemia increased plasma inflammatory markers, but did not impact skeletal muscle inflammatory gene expression. Gene expression related to ketone and fatty acid metabolism in skeletal muscle increased in response to hyperlipidemia. CONCLUSION This work provides important insight into the role of ketones in human health and suggests that ketone body metabolism is altered at the onset of lipid-induced insulin resistance.
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Affiliation(s)
- J T Mey
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - B Vandagmansar
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - W S Dantas
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - K P Belmont
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - C L Axelrod
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
| | - J P Kirwan
- Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA
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2
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Mason SA, Parker L, van der Pligt P, Wadley GD. Vitamin C supplementation for diabetes management: A comprehensive narrative review. Free Radic Biol Med 2023; 194:255-283. [PMID: 36526243 DOI: 10.1016/j.freeradbiomed.2022.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/01/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022]
Abstract
Growing evidence suggests that vitamin C supplementation may be an effective adjunct therapy in the management of people with diabetes. This paper critically reviews the current evidence on effects of vitamin C supplementation and its potential mechanisms in diabetes management. Evidence from meta-analyses of randomized controlled trials (RCTs) show favourable effects of vitamin C on glycaemic control and blood pressure that may be clinically meaningful, and mixed effects on blood lipids and endothelial function. However, evidence is mostly of low evidence certainty. Emerging evidence is promising for effects of vitamin C supplementation on some diabetes complications, particularly diabetic foot ulcers. However, there is a notable lack of robust and well-designed studies exploring effects of vitamin C as a single compound supplement on diabetes prevention and patient-important outcomes (i.e. prevention and amelioration of diabetes complications). RCTs are also required to investigate potential preventative or ameliorative effects of vitamin C on gestational diabetes outcomes. Oral vitamin C doses of 500-1000 mg per day are potentially effective, safe, and affordable for many individuals with diabetes. However, personalisation of supplementation regimens that consider factors such as vitamin C status, disease status, current glycaemic control, vitamin C intake, redox status, and genotype is important to optimize vitamin C's therapeutic effects safely. Finally, given a high prevalence of vitamin C deficiency in patients with complications, it is recommended that plasma vitamin C concentration be measured and monitored in the clinic setting.
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Affiliation(s)
- Shaun A Mason
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.
| | - Lewan Parker
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Paige van der Pligt
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia; Department of Nutrition and Dietetics, Western Health, Footscray, Australia
| | - Glenn D Wadley
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
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3
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McKeegan K, Mason SA, Trewin AJ, Keske MA, Wadley GD, Della Gatta PA, Nikolaidis MG, Parker L. Reactive oxygen species in exercise and insulin resistance: Working towards personalized antioxidant treatment. Redox Biol 2021; 44:102005. [PMID: 34049222 PMCID: PMC8167146 DOI: 10.1016/j.redox.2021.102005] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 04/25/2021] [Accepted: 05/06/2021] [Indexed: 12/11/2022] Open
Abstract
Reactive oxygen species (ROS) are well known for their role in insulin resistance and the development of cardiometabolic disease including type 2 diabetes mellitus (T2D). Conversely, evidence supports the notion that ROS are a necessary component for glucose cell transport and adaptation to physiological stress including exercise and muscle contraction. Although genetic rodent models and cell culture studies indicate antioxidant treatment to be an effective strategy for targeting ROS to promote health, human findings are largely inconsistent. In this review we discuss human research that has investigated antioxidant treatment and glycemic control in the context of health (healthy individuals and during exercise) and disease (insulin resistance and T2D). We have identified key factors that are likely to influence the effectiveness of antioxidant treatment: 1) the context of treatment including whether oxidative distress or eustress is present (e.g., hyperglycemia/lipidaemia or during exercise and muscle contraction); 2) whether specific endogenous antioxidant deficiencies are identified (redox screening); 3) whether antioxidant treatment is specifically designed to target and restore identified deficiencies (antioxidant specificity); 4) and the bioavailability and bioactivity of the antioxidant which are influenced by treatment dose, duration, and method of administration. The majority of human research has failed to account for these factors, limiting their ability to robustly test the effectiveness of antioxidants for health promotion and disease prevention. We propose that a modern "redox screening" and "personalized antioxidant treatment" approach is required to robustly explore redox regulation of human physiology and to elicit more effective antioxidant treatment in humans.
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Affiliation(s)
- Kathryn McKeegan
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Shaun A Mason
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Adam J Trewin
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Michelle A Keske
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Glenn D Wadley
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Paul A Della Gatta
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Michalis G Nikolaidis
- Department of Physical Education and Sport Science at Serres, Aristotle University of Thessaloniki, Serres, Greece
| | - Lewan Parker
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia.
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Park S, Park SY. Can antioxidants be effective therapeutics for type 2 diabetes? Yeungnam Univ J Med 2020; 38:83-94. [PMID: 33028055 PMCID: PMC8016622 DOI: 10.12701/yujm.2020.00563] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 08/31/2020] [Indexed: 12/14/2022] Open
Abstract
The global obesity epidemic and the growing elderly population largely contribute to the increasing incidence of type 2 diabetes. Insulin resistance acts as a critical link between the present obesity pandemic and type 2 diabetes. Naturally occurring reactive oxygen species (ROS) regulate intracellular signaling and are kept in balance by the antioxidant system. However, the imbalance between ROS production and antioxidant capacity causes ROS accumulation and induces oxidative stress. Oxidative stress interrupts insulin-mediated intracellular signaling pathways, as supported by studies involving genetic modification of antioxidant enzymes in experimental rodents. In addition, a close association between oxidative stress and insulin resistance has been reported in numerous human studies. However, the controversial results with the use of antioxidants in type 2 diabetes raise the question of whether oxidative stress plays a critical role in insulin resistance. In this review article, we discuss the relevance of oxidative stress to insulin resistance based on genetically modified animal models and human trials.
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Affiliation(s)
- Soyoung Park
- Department of Physiology and Smart-aging Convergence Research Center, Yeungnam University College of Medicine, Daegu, Korea
| | - So-Young Park
- Department of Physiology and Smart-aging Convergence Research Center, Yeungnam University College of Medicine, Daegu, Korea
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Nishida Y, Nawaz A, Kado T, Takikawa A, Igarashi Y, Onogi Y, Wada T, Sasaoka T, Yamamoto S, Sasahara M, Imura J, Tokuyama K, Usui I, Nakagawa T, Fujisaka S, Kunimasa Y, Tobe K. Astaxanthin stimulates mitochondrial biogenesis in insulin resistant muscle via activation of AMPK pathway. J Cachexia Sarcopenia Muscle 2020; 11:241-258. [PMID: 32003547 PMCID: PMC7015247 DOI: 10.1002/jcsm.12530] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 09/30/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Skeletal muscle is mainly responsible for insulin-stimulated glucose disposal. Dysfunction in skeletal muscle metabolism especially during obesity contributes to the insulin resistance. Astaxanthin (AX), a natural antioxidant, has been shown to ameliorate hepatic insulin resistance in obese mice. However, its effects in skeletal muscle are poorly understood. The current study aimed to investigate the molecular target of AX in ameliorating skeletal muscle insulin resistance. METHODS We fed 6-week-old male C57BL/6J mice with normal chow (NC) or NC supplemented with AX (NC+AX) and high-fat-diet (HFD) or HFD supplemented with AX for 24 weeks. We determined the effect of AX on various parameters including insulin sensitivity, glucose uptake, inflammation, kinase signaling, gene expression, and mitochondrial function in muscle. We also determined energy metabolism in intact C2C12 cells treated with AX using the Seahorse XFe96 Extracellular Flux Analyzer and assessed the effect of AX on mitochondrial oxidative phosphorylation and mitochondrial biogenesis. RESULTS AX-treated HFD mice showed improved metabolic status with significant reduction in blood glucose, serum total triglycerides, and cholesterol (p< 0.05). AX-treated HFD mice also showed improved glucose metabolism by enhancing glucose incorporation into peripheral target tissues, such as the skeletal muscle, rather than by suppressing gluconeogenesis in the liver as shown by hyperinsulinemic-euglycemic clamp study. AX activated AMPK in the skeletal muscle of the HFD mice and upregulated the expressions of transcriptional factors and coactivator, thereby inducing mitochondrial remodeling, including increased mitochondrial oxidative phosphorylation component and free fatty acid metabolism. We also assessed the effects of AX on mitochondrial biogenesis in the siRNA-mediated AMPK-depleted C2C12 cells and showed that the effect of AX was lost in the genetically AMPK-depleted C2C12 cells. Collectively, AX treatment (i) significantly ameliorated insulin resistance and glucose intolerance through regulation of AMPK activation in the muscle, (ii) stimulated mitochondrial biogenesis in the muscle, (iii) enhanced exercise tolerance and exercise-induced fatty acid metabolism, and (iv) exerted antiinflammatory effects via its antioxidant activity in adipose tissue. CONCLUSIONS We concluded that AX treatment stimulated mitochondrial biogenesis and significantly ameliorated insulin resistance through activation of AMPK pathway in the skeletal muscle.
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Affiliation(s)
- Yasuhiro Nishida
- First Department of Internal Medicine, University of Toyama, Toyama, Japan.,Fuji Chemical Industries, Co., Ltd., Toyama, Japan
| | - Allah Nawaz
- First Department of Internal Medicine, University of Toyama, Toyama, Japan.,Department of Metabolism and Nutrition, University of Toyama, Toyama, Japan
| | - Tomonobu Kado
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Akiko Takikawa
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Yoshiko Igarashi
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Yasuhiro Onogi
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Tsutomu Wada
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Toshiyasu Sasaoka
- Department of Clinical Pharmacology, University of Toyama, Toyama, Japan
| | - Seiji Yamamoto
- Department of Pathology, University of Toyama, Toyama, Japan
| | | | - Johji Imura
- Department of Diagnostic Pathology, University of Toyama, Toyama, Japan
| | - Kumpei Tokuyama
- Doctoral Program in Sports Medicine, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Isao Usui
- Department of Endocrinology and Metabolism, Dokkyo Medical University, Tochigi, Japan
| | - Takashi Nakagawa
- Department of Metabolism and Nutrition, University of Toyama, Toyama, Japan
| | - Shiho Fujisaka
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Yagi Kunimasa
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
| | - Kazuyuki Tobe
- First Department of Internal Medicine, University of Toyama, Toyama, Japan
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Effect of a p38 MAPK inhibitor on FFA-induced hepatic insulin resistance in vivo. Nutr Diabetes 2016; 6:e210. [PMID: 27136448 PMCID: PMC4895375 DOI: 10.1038/nutd.2016.11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2015] [Revised: 02/11/2016] [Accepted: 02/21/2016] [Indexed: 01/30/2023] Open
Abstract
The mechanisms whereby prolonged plasma free fatty acids elevation, as found in obesity, causes hepatic insulin resistance are not fully clarified. We herein investigated whether inhibition of p38 mitogen-activated protein kinase (MAPK) prevented hepatic insulin resistance following prolonged lipid infusion. Chronically cannulated rats were subdivided into one of four intravenous (i.v.) treatments that lasted 48 h: Saline (5.5 μl min−1), Intralipid plus heparin (IH, 20% Intralipid+20 U ml−1 heparin; 5.5 μl min−1), IH+p38 MAPK inhibitor (SB239063) and SB239063 alone. During the last 2 h of treatment, a hyperinsulinemic (5 mU kg−1 min−1) euglycemic clamp together with [3-3H] glucose methodology was carried out to distinguish hepatic from peripheral insulin sensitivity. We found that SB239063 prevented IH-induced hepatic insulin resistance, but not peripheral insulin resistance. SB239063 also prevented IH-induced phosphorylation of activating transcription factor 2 (ATF2), a marker of p38 MAPK activity, in the liver. Moreover, in another lipid infusion model in mice, SB239063 prevented hepatic but not peripheral insulin resistance caused by 48 h combined ethyloleate plus ethylpalmitate infusion. Our results suggest that inhibition of p38 MAPK may be a useful strategy in alleviating hepatic insulin resistance in obesity-associated disorders.
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Niu S, Wang L, He M, Peng Y, Li S. Exendin-4 regulates redox homeostasis in rats fed with high-fat diet. Acta Biochim Biophys Sin (Shanghai) 2015; 47:397-403. [PMID: 25910576 DOI: 10.1093/abbs/gmv027] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 02/15/2015] [Indexed: 12/29/2022] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is associated with increased plasma homocysteine level, which is caused by down-regulation of hepatic cystathionine beta-synthase (CBS) activity. CBS catalyzes the first step in the transsulfuration of homocysteine to cysteine, which contributes ∼50% of the cysteine required for hepatic biosynthesis of glutathione (GSH), the most abundant antioxidant in cells. As the glucagon-like peptide-1 (GLP-1) receptor agonists (e.g. exendin-4) effectively reverse hepatic steatosis, the effect of exendin-4 on both homocysteine and redox status was investigated in the livers of rats fed with high-fat diet (HFD). It was found that HFD down-regulated CBS protein expression, which was probably due to induction of rno-miR-376c expression in the liver. The level of GSH was markedly reduced, whereas the level of malonydialdehyde, an indicator of lipid peroxidation, was significantly increased in the livers of rats fed with HFD. Exendin-4 treatment increased hepatic CBS protein and GSH levels, and reduced malonydialdehyde level in hyperlipidemic rats. Our findings suggest that GLP-1 receptor agonists have beneficial effects on redox homeostasis in NAFLD.
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Affiliation(s)
- Shiwei Niu
- Department of Biochemistry, Kunming Medical University, Kunming 650031, China
| | - Liqiong Wang
- Department of Pathology, Yan'an Hospital, Kunming 650051, China
| | - Ming He
- Department of Biochemistry, Kunming Medical University, Kunming 650031, China
| | - Yunzhu Peng
- Department of Cardiology, The First Affiliated Hospital, Kunming Medical University, Kunming 650032, China
| | - Shude Li
- Department of Biochemistry, Kunming Medical University, Kunming 650031, China
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8
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Niu S, Wang L, He M, Peng Y, Li S. Exendin-4 regulates redox homeostasis in rats fed with high-fat diet. Acta Biochim Biophys Sin (Shanghai) 2015. [DOI: 10.1093/abbs/gmv027 order by 31548--] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Pereira S, Shah A, George Fantus I, Joseph JW, Giacca A. Effect of N-acetyl-l-cysteine on insulin resistance caused by prolonged free fatty acid elevation. J Endocrinol 2015; 225:1-7. [PMID: 25609734 DOI: 10.1530/joe-14-0676] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Circulating free fatty acids (FFAs) are elevated in obesity and cause insulin resistance. The objective of the current study was to determine whether the antioxidant N-acetyl-l-cysteine (NAC) prevented hepatic and peripheral insulin resistance caused by prolonged elevation of plasma FFAs. Chronically cannulated Wistar rats received saline (SAL), Intralipid plus heparin (IH), IH plus NAC, or NAC i.v. infusion for 48 h. Insulin sensitivity was determined using the hyperinsulinemic-euglycemic clamp with tritiated glucose tracer. IH induced hepatic and peripheral insulin resistance (P<0.05). NAC co-infusion did not prevent insulin resistance in the liver, although it was able to prevent peripheral insulin resistance. Prolonged IH infusion did not appear to induce oxidative stress in the liver because hepatic content of protein carbonyl, malondialdehyde, and reduced to oxidized glutathione ratio did not differ across treatment groups. In alignment with our insulin sensitivity results, IH augmented skeletal muscle protein carbonyl content and this was prevented by NAC co-infusion. Taken together, our results indicate that oxidative stress mediates peripheral, but not hepatic, insulin resistance resulting from prolonged plasma FFA elevation. Thus, in states of chronic plasma FFA elevation, such as obesity, antioxidants may protect against peripheral but not hepatic insulin resistance.
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Affiliation(s)
- Sandra Pereira
- Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada
| | - Anu Shah
- Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada
| | - I George Fantus
- Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo
| | - Jamie W Joseph
- Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada
| | - Adria Giacca
- Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo, Waterloo, Ontario, Canada Department of PhysiologyUniversity of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, Ontario, Canada M5S 1A8Department of MedicineUniversity of Toronto, Toronto, Ontario, CanadaToronto General Research InstituteUniversity Health Network, Toronto, Ontario, CanadaBanting and Best Diabetes CentreUniversity of Toronto, Toronto, Ontario, CanadaInstitute of Medical ScienceUniversity of Toronto, Toronto, Ontario, CanadaSchool of PharmacyUniversity of Waterloo
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Montgomery MK, Turner N. Mitochondrial dysfunction and insulin resistance: an update. Endocr Connect 2015; 4:R1-R15. [PMID: 25385852 PMCID: PMC4261703 DOI: 10.1530/ec-14-0092] [Citation(s) in RCA: 356] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 11/10/2014] [Indexed: 12/11/2022]
Abstract
Mitochondrial dysfunction has been implicated in the development of insulin resistance (IR); however, a large variety of association and intervention studies as well as genetic manipulations in rodents have reported contrasting results. Indeed, even 39 years after the first publication describing a relationship between IR and diminished mitochondrial function, it is still unclear whether a direct relationship exists, and more importantly if changes in mitochondrial capacity are a cause or consequence of IR. This review will take a journey through the past and summarise the debate about the occurrence of mitochondrial dysfunction and its possible role in causing decreased insulin action in obesity and type 2 diabetes. Evidence is presented from studies in various human populations, as well as rodents with genetic manipulations of pathways known to affect mitochondrial function and insulin action. Finally, we have discussed whether mitochondria are a potential target for the treatment of IR.
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Affiliation(s)
- Magdalene K Montgomery
- Department of PharmacologyUNSW Medicine, School of Medical Sciences, University of New South Wales, Kensington, Sydney, New South Wales 2052, Australia
| | - Nigel Turner
- Department of PharmacologyUNSW Medicine, School of Medical Sciences, University of New South Wales, Kensington, Sydney, New South Wales 2052, Australia
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Vitamin D and L-cysteine levels correlate positively with GSH and negatively with insulin resistance levels in the blood of type 2 diabetic patients. Eur J Clin Nutr 2014; 68:1148-53. [PMID: 24961547 PMCID: PMC4192028 DOI: 10.1038/ejcn.2014.114] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 04/30/2014] [Accepted: 05/07/2014] [Indexed: 12/13/2022]
Abstract
Background/Objectives: Vitamin D, L-cysteine (LC) and glutathione (GSH) levels are lower in the blood of diabetic patients. This study examined the hypothesis that the levels of vitamin D and LC correlate with those of GSH in the blood of type 2 diabetic patients (T2D), and that vitamin D and LC upregulate glutamate–cysteine ligase (GCLC), which catalyzes GSH biosynthesis, in cultured monocytes. Subjects/Methods: Fasting blood was obtained after written informed consent from T2D (n=79) and healthy controls (n=22). U937 monocytes were pretreated with 1,25 (OH)2 vitamin D (0–25 nM) or LC (0–500 μM) for 24 h and then exposed to control or high glucose (25 mM) for 4 h. Results: Plasma levels of vitamin D, LC, GSH and GCLC protein were significantly lower in T2D versus those in age-matched healthy controls. Multiple linear regression analyses and adjustment for body weight showed a significant positive correlation between plasma levels of vitamin D (r=0.26, P=0.05) and LC (r=0.81, P=0.001) and that of GSH, and between LC and vitamin D (r=0.27, P=0.045) levels. Plasma levels of GSH (r=−0.34, P=0.01) and LC (r=−0.33, r=0.01) showed a negative correlation with triglyceride levels. Vitamin D correlated inversely with HbA1C (−0.30, P=0.01) and homeostatic model assessment insulin resistance (r=−0.31, P=0.03), which showed a significant positive correlation with triglycerides (r=0.44, P=0.001) in T2D. Cell culture studies demonstrate that supplementation with vitamin D and LC significantly increased GCLC expression and GSH formation in control and high-glucose-treated monocytes. Conclusions: This study suggests a positive relationship between the concentrations of the micronutrients vitamin D and LC and that of GSH. Some of the beneficial effects of vitamin D and LC supplementation may be mediated by an increase in the levels of GSH and a decrease in triglyceride levels in T2D patients.
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Ju TJ, Kwon WY, Kim YW, Kim JY, Kim YD, Lee IK, Park SY. Hemin Improves Insulin Sensitivity in Skeletal Muscle in High Fat–Fed Mice. J Pharmacol Sci 2014; 126:115-25. [DOI: 10.1254/jphs.14003fp] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Jain SK, Micinski D. Vitamin D upregulates glutamate cysteine ligase and glutathione reductase, and GSH formation, and decreases ROS and MCP-1 and IL-8 secretion in high-glucose exposed U937 monocytes. Biochem Biophys Res Commun 2013; 437:7-11. [PMID: 23770363 DOI: 10.1016/j.bbrc.2013.06.004] [Citation(s) in RCA: 163] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2013] [Accepted: 06/03/2013] [Indexed: 11/25/2022]
Abstract
INTRODUCTION Glutathione is a major endogenous antioxidant and its deficiency is implicated in the etiology and progression of a number of human diseases. Vitamin D is important for the prevention of osteoporosis, cardiovascular disease, diabetes, autoimmune diseases, and some cancers. Using a monocyte cell model, this study examined the hypothesis that vitamin D upregulate glutamate cysteine ligase (GCLC) and glutathione reductase (GR), which catalyzes GSH biosynthesis. METHODS U937 monocytes were pretreated with and without 1,25 (OH)₂ vitamin D (10-25 nM) for 24 h and then exposed to control and high glucose (HG, 25 mM) for 4h. Levels of GSH determined using HPLC; GR activity by oxidation of NADPH; GCLC protein, MCP-1 and IL-8 using ELISA kits. RESULTS 1,25 (OH)₂ vitamin D supplementation significantly upregulated expression of GCLC and GR, levels of GCLC protein and GR activity, and formation of GSH in control and HG-treated monocytes. 1,25 (OH)₂ vitamin D caused significantly (p<0.05) lower secretion of IL-8 and MCP-1, and lower ROS levels in monocytes exposed to control and HG-treated monocytes. CONCLUSIONS This study demonstrates a positive link between vitamin D and GSH levels, and that some beneficial effects of vitamin D supplementation may be mediated by an improvement in the cellular GSH levels and a decrease in ROS and pro-inflammatory cytokines.
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Affiliation(s)
- Sushil K Jain
- Department of Pediatrics, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States.
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Lee-Young RS, Bonner JS, Mayes WH, Iwueke I, Barrick BA, Hasenour CM, Kang L, Wasserman DH. AMP-activated protein kinase (AMPK)α2 plays a role in determining the cellular fate of glucose in insulin-resistant mouse skeletal muscle. Diabetologia 2013; 56:608-17. [PMID: 23224579 PMCID: PMC4075509 DOI: 10.1007/s00125-012-2787-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 11/01/2012] [Indexed: 12/25/2022]
Abstract
AIMS/HYPOTHESIS We determined whether: (1) an acute lipid infusion impairs skeletal muscle AMP-activated protein kinase (AMPK)α2 activity, increases inducible nitric oxide synthase (iNOS) and causes peripheral insulin resistance in conscious, unstressed, lean mice; and (2) restoration of AMPKα2 activity during the lipid infusion attenuates the increase in iNOS and reverses the defect in insulin sensitivity in vivo. METHODS Chow-fed, 18-week-old C57BL/6J male mice were surgically catheterised. After 5 days they received: (1) a 5 h infusion of 5 ml kg(-1) h(-1) Intralipid + 6 U/h heparin (Lipid treatment) or saline (Control); (2) Lipid treatment or Control, followed by a 2 h hyperinsulinaemic-euglycaemic clamp (insulin clamp; 4 mU kg(-1) min(-1)); and (3) infusion of the AMPK activator, 5-aminoimidazole-4-carboxamide 1-β-D-ribofuranoside (AICAR) (1 mg kg(-1) min(-1)), or saline during Lipid treatment, followed by a 2 h insulin clamp. In a separate protocol, mice producing a muscle-specific kinase-dead AMPKα2 subunit (α2-KD) underwent an insulin clamp to determine the role of AMPKα2 in insulin-mediated muscle glucose metabolism. RESULTS Lipid treatment decreased AMPKα2 activity, increased iNOS abundance/activation and reduced whole-body insulin sensitivity in vivo. AICAR increased AMPKα2 activity twofold; this did not suppress iNOS or improve whole-body or tissue-specific rates of glucose uptake during Lipid treatment. AICAR caused a marked increase in insulin-mediated glycogen synthesis in skeletal muscle. Consistent with this latter result, lean α2-KD mice exhibited impaired insulin-stimulated glycogen synthesis even though muscle glucose uptake was not affected. CONCLUSIONS/INTERPRETATION Acute induction of insulin resistance via lipid infusion in healthy mice impairs AMPKα2, increases iNOS and causes insulin resistance in vivo. However, these changes do not appear to be interrelated. Rather, a functionally active AMPKα2 subunit is required for insulin-stimulated muscle glycogen synthesis.
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Affiliation(s)
- R S Lee-Young
- Cellular and Molecular Metabolism Laboratory, Division of Metabolism and Obesity, Baker IDI Heart and Diabetes Institute, 75 Commercial Rd, Melbourne, VIC 3004, Australia.
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Inoue N, Hidaka S, Miura N, Yamada K, Fukahori M, Maruyama M, Kawahara S, Ohta K, Muguruma M. Effects of Liver Hydrolysate on the Blood Glucose in Metabolic Syndrome Model Rats (SHR/NDmcr-cp). YAKUGAKU ZASSHI 2013; 133:117-23. [DOI: 10.1248/yakushi.y110185] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Naonori Inoue
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki
- Consumer Healthcare Laboratories, Central Research Laboratories, Zeria Pharmaceutical Co., Ltd
| | - Shuji Hidaka
- Laboratory of Food Science and Nutrition, Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki
| | - Naoyoshi Miura
- Consumer Healthcare Laboratories, Central Research Laboratories, Zeria Pharmaceutical Co., Ltd
| | - Kotaro Yamada
- Consumer Healthcare Products Development, Zeria Pharmaceutical Co., Ltd
| | - Masahiro Fukahori
- Consumer Healthcare Products Development, Zeria Pharmaceutical Co., Ltd
| | - Masugi Maruyama
- Department of Applied Physiology, Faculty of Medicine, University of Miyazaki
| | - Satoshi Kawahara
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki
- Laboratory of Food Science and Nutrition, Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki
| | - Kazuyoshi Ohta
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki
- Laboratory of Food Science and Nutrition, Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki
| | - Michio Muguruma
- Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki
- Laboratory of Food Science and Nutrition, Department of Biochemistry and Applied Biosciences, Faculty of Agriculture, University of Miyazaki
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Tovmasyan A, Sheng H, Weitner T, Arulpragasam A, Lu M, Warner DS, Vujaskovic Z, Spasojevic I, Batinic-Haberle I. Design, mechanism of action, bioavailability and therapeutic effects of mn porphyrin-based redox modulators. Med Princ Pract 2012; 22:103-30. [PMID: 23075911 PMCID: PMC3640855 DOI: 10.1159/000341715] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2012] [Accepted: 07/01/2012] [Indexed: 12/18/2022] Open
Abstract
Based on aqueous redox chemistry and simple in vivo models of oxidative stress, Escherichia coli and Saccharomyces cerevisiae, the cationic Mn(III) N-substituted pyridylporphyrins (MnPs) have been identified as the most potent cellular redox modulators within the porphyrin class of drugs; their efficacy in animal models of diseases that have oxidative stress in common is based on their high ability to catalytically remove superoxide, peroxynitrite, carbonate anion radical, hypochlorite, nitric oxide, lipid peroxyl and alkoxyl radicals, thus suppressing the primary oxidative event. While doing so MnPs could couple with cellular reductants and redox-active proteins. Reactive species are widely accepted as regulators of cellular transcriptional activity: minute, nanomolar levels are essential for normal cell function, while submicromolar or micromolar levels impose oxidative stress, which is evidenced in increased inflammatory and immune responses. By removing reactive species, MnPs affect redox-based cellular transcriptional activity and consequently secondary oxidative stress, and in turn inflammatory processes. The equal ability to reduce and oxidize superoxide during the dismutation process and recently accumulated results suggest that pro-oxidative actions of MnPs may also contribute to their therapeutic effects. All our data identify the superoxide dismutase-like activity, estimated by log k(cat)O2-*), as a good measure for the therapeutic efficacy of MnPs. Their accumulation in mitochondria and their ability to cross the blood-brain barrier contribute to their remarkable efficacy. We summarize herein the therapeutic effects of MnPs in cancer, central nervous system injuries, diabetes, their radioprotective action and potential for imaging. Few of the most potent modulators of cellular redox-based pathways, MnTE2-PyP5+, MnTDE-2-ImP5+, MnTnHex-2-PyP5+ and MnTnBuOE-2-PyP5+, are under preclinical and clinical development.
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Affiliation(s)
- Artak Tovmasyan
- Department of Radiation Oncology, Duke University Medical
Center, Durham, N.C., USA
| | - Huaxin Sheng
- Department of Anesthesiology, Duke University Medical Center,
Durham, N.C., USA
- Department of Multidisciplinary Neuroprotection Laboratories,
Duke University Medical Center, Durham, N.C., USA
| | - Tin Weitner
- Department of Radiation Oncology, Duke University Medical
Center, Durham, N.C., USA
| | - Amanda Arulpragasam
- Department of Duke University Neuroscience Undergraduate
Program, Duke University Medical Center, Durham, N.C., USA
| | - Miaomiao Lu
- Department of Anesthesiology, Duke University Medical Center,
Durham, N.C., USA
- Department of Multidisciplinary Neuroprotection Laboratories,
Duke University Medical Center, Durham, N.C., USA
- Department of Department of Anesthesiology, Second Affiliated
Hospital, Zhengzhou University, Zhengzhou, China
| | - David S. Warner
- Department of Anesthesiology, Duke University Medical Center,
Durham, N.C., USA
- Department of Multidisciplinary Neuroprotection Laboratories,
Duke University Medical Center, Durham, N.C., USA
| | - Zeljko Vujaskovic
- Department of Radiation Oncology, Duke University Medical
Center, Durham, N.C., USA
| | - Ivan Spasojevic
- Department of Medicine, Duke University Medical Center, Durham,
N.C., USA
| | - Ines Batinic-Haberle
- Department of Radiation Oncology, Duke University Medical
Center, Durham, N.C., USA
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Cha HN, Song SE, Kim YW, Kim JY, Won KC, Park SY. Lack of inducible nitric oxide synthase prevents lipid-induced skeletal muscle insulin resistance without attenuating cytokine level. J Pharmacol Sci 2012; 117:77-86. [PMID: 22001626 DOI: 10.1254/jphs.11093fp] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022] Open
Abstract
We examined whether deletion of inducible nitric oxide synthase (iNOS) could prevent lipid infusion-induced insulin resistance in iNOS-knockout and wild-type mice with the in vivo euglycemic-hyperinsulinemic clamp technique. Plasma NO metabolites were increased in lipid-infused wild-type mice, while they were not increased in iNOS-knockout mice. Plasma tumor necrosis factor-α levels were increased in both wild-type and iNOS-knockout by lipid-infusion. Lipid infusion reduced glucose infusion rate (GIR) and whole body glucose uptake in wild-type mice, whereas iNOS-knockout mice displayed comparable GIR and whole body glucose uptake compared with the control. In the gastrocnemius, lipid infusion decreased glucose uptake and glycolysis that were accompanied with increased phosphorylation of c-Jun N-terminal kinase and reduced phosphorylation of phosphoinositide 3-kinases and serine/threonine kinase Akt. However, lipid infusion did not affect glucose uptake or phosphorylation of these proteins in iNOS-knockout mice. The mRNA levels of inflammatory cytokines were also increased in the gastrocnemis of wild-type and iNOS-knockout mice by lipid infusion. Nitrotyrosine level in the gastrocnemius was increased in lipid-infused wild-type mice but it was not increased in iNOS-knockout mice. These results suggest that lack of iNOS prevents lipid infusion-induced skeletal muscle insulin resistance without attenuating cytokine levels.
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Affiliation(s)
- Hye-Na Cha
- Department of Physiology, College of Medicine, Yeungnam University, South Korea
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Li Y, Wende AR, Nunthakungwan O, Huang Y, Hu E, Jin H, Boudina S, Abel ED, Jalili T. Cytosolic, but not mitochondrial, oxidative stress is a likely contributor to cardiac hypertrophy resulting from cardiac specific GLUT4 deletion in mice. FEBS J 2012; 279:599-611. [PMID: 22221582 DOI: 10.1111/j.1742-4658.2011.08450.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We hypothesized that oxidative stress may contribute to the development of hypertrophy observed in mice with cardiac specific ablation of the insulin sensitive glucose transporter 4 gene (GLUT4, G4H(-/-) ). Measurements of oxidized glutathione (GSSG) in isolated mitochondria and whole heart homogenates were increased resulting in a lower ratio of reduced glutathione (GSH) to GSSG. Membrane translocation of the p67(phox) subunit of cardiac NADPH oxidase 2 (NOX2) was markedly increased in G4H(-/-) mice, suggesting elevated activity. To determine if oxidative stress was contributing to cardiac hypertrophy, 4-week-old control (Con) and G4H(-/-) mice were treated with either tempol (T, 1 mm, drinking water), a whole cell antioxidant, or Mn(III) tetrakis (4-benzoic acid) porphyrin chloride (MnTBAP, 10 mg·kg(-1) , intraperitoneally), a mitochondrial targeted antioxidant, for 28 days. Tempol attenuated cardiac hypertrophy in G4H(-/-) mice (heart : tibia, Con 6.82 ± 0.35, G4H(-/-) 8.83 ± 0.34, Con + T 6.82 ± 0.46, G4H(-/-) + T 7.57 ± 0.3), without changing GSH : GSSG, glutathione peroxidase 4 or membrane translocation of the p67(phox) . Tempol did not modify phosphorylation of glycogen synthase kinase 3β or thioredoxin-2. In contrast, MnTBAP lowered mitochondrial GSSG and improved GSH : GSSG, but did not prevent hypertrophy, indicating that mitochondrial oxidative stress may not be critical for hypertrophy in this model. The ability of tempol to attenuate cardiac hypertrophy suggests that a cytosolic source of reactive oxygen species, probably NOX2, may contribute to the hypertrophic phenotype in G4H(-/-) mice.
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Affiliation(s)
- Yan Li
- University of Utah, Salt Lake City, UT, USA
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Maekawa H, Matsunobu T, Satoh Y, Kurioka T, Nakamura A, Iwakami N, Shiotani A. Protective Effect of Neurotrophic Agent T-817MA Against Inner Ear Barotrauma in the Guinea Pig. J Pharmacol Sci 2011; 117:67-70. [DOI: 10.1254/jphs.11033sc] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Perry J, Shin D, Getzoff E, Tainer J. The structural biochemistry of the superoxide dismutases. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1804:245-62. [PMID: 19914407 PMCID: PMC3098211 DOI: 10.1016/j.bbapap.2009.11.004] [Citation(s) in RCA: 322] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2009] [Revised: 11/04/2009] [Accepted: 11/05/2009] [Indexed: 01/11/2023]
Abstract
The discovery of superoxide dismutases (SODs), which convert superoxide radicals to molecular oxygen and hydrogen peroxide, has been termed the most important discovery of modern biology never to win a Nobel Prize. Here, we review the reasons this discovery has been underappreciated, as well as discuss the robust results supporting its premier biological importance and utility for current research. We highlight our understanding of SOD function gained through structural biology analyses, which reveal important hydrogen-bonding schemes and metal-binding motifs. These structural features create remarkable enzymes that promote catalysis at faster than diffusion-limited rates by using electrostatic guidance. These architectures additionally alter the redox potential of the active site metal center to a range suitable for the superoxide disproportionation reaction and protect against inhibition of catalysis by molecules such as phosphate. SOD structures may also control their enzymatic activity through product inhibition; manipulation of these product inhibition levels has the potential to generate therapeutic forms of SOD. Markedly, structural destabilization of the SOD architecture can lead to disease, as mutations in Cu,ZnSOD may result in familial amyotrophic lateral sclerosis, a relatively common, rapidly progressing and fatal neurodegenerative disorder. We describe our current understanding of how these Cu,ZnSOD mutations may lead to aggregation/fibril formation, as a detailed understanding of these mechanisms provides new avenues for the development of therapeutics against this so far untreatable neurodegenerative pathology.
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Affiliation(s)
- J.J.P. Perry
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- The School of Biotechnology, Amrita University, Kollam, Kerala 690525, India
| | - D.S. Shin
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - E.D. Getzoff
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - J.A. Tainer
- Skaggs Institute for Chemical Biology and Department of Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
- Life Sciences Division, Department of Molecular Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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