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Yu J, Qiu J, Zhang Z, Cui X, Guo W, Sheng M, Gao M, Wang D, Xu L, Ma X. Redox Biology in Adipose Tissue Physiology and Obesity. Adv Biol (Weinh) 2023; 7:e2200234. [PMID: 36658733 DOI: 10.1002/adbi.202200234] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/24/2022] [Indexed: 01/21/2023]
Abstract
Reactive oxygen species (ROS), a by-product of mitochondrial oxidative phosphorylation and cellular metabolism, is vital for cellular survival, proliferation, damage, and senescence. In recent years, studies have shown that ROS levels and redox status in adipose tissue are strongly associated with obesity and metabolic diseases. Although it was previously considered that excessive production of ROS and impairment of antioxidant capability leads to oxidative stress and potentially contributes to increased adiposity, it has become increasingly evident that an adequate amount of ROS is vital for adipocyte differentiation and thermogenesis. In this review, by providing a systematic overview of the recent understanding of the key factors of redox systems, endogenous mechanisms for redox homeostasis, advanced techniques for dynamic redox monitoring, as well as exogenous stimuli for redox production in adipose tissues and obesity, the importance of redox biology in metabolic health is emphasized.
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Affiliation(s)
- Jian Yu
- Department of Endocrinology and Metabolism, Fengxian Central Hospital Affiliated to Southern Medical University, Shanghai, 201499, P. R. China
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Jin Qiu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Zhe Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Xiangdi Cui
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Wenxiu Guo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Maozheng Sheng
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Mingyuan Gao
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Dongmei Wang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Lingyan Xu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
| | - Xinran Ma
- Department of Endocrinology and Metabolism, Fengxian Central Hospital Affiliated to Southern Medical University, Shanghai, 201499, P. R. China
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, Shanghai, 200241, P. R. China
- Chongqing Key Laboratory of Precision Optics, Chongqing Institute of East China Normal University, Chongqing, 401120, P. R. China
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Bagheripour F, Jeddi S, Kashfi K, Ghasemi A. Metabolic effects of L-citrulline in type 2 diabetes. Acta Physiol (Oxf) 2023; 237:e13937. [PMID: 36645144 DOI: 10.1111/apha.13937] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 01/01/2023] [Accepted: 01/10/2023] [Indexed: 01/17/2023]
Abstract
The prevalence of type 2 diabetes (T2D) is increasing worldwide. Decreased nitric oxide (NO) bioavailability is involved in the pathophysiology of T2D and its complications. L-citrulline (Cit), a precursor of NO production, has been suggested as a novel therapeutic agent for T2D. Available data from human and animal studies indicate that Cit supplementation in T2D increases circulating levels of Cit and L-arginine while decreasing circulating glucose and free fatty acids and improving dyslipidemia. The underlying mechanisms for these beneficial effects of Cit include increased insulin secretion from the pancreatic β cells, increased glucose uptake by the skeletal muscle, as well as increased lipolysis and β-oxidation, and decreased glyceroneogenesis in the adipose tissue. Thus, Cit has antihyperglycemic, antidyslipidemic, and antioxidant effects and has the potential to be used as a new therapeutic agent in the management of T2D. This review summarizes available literature from human and animal studies to explore the effects of Cit on metabolic parameters in T2D. It also discusses the possible mechanisms underlying Cit-induced improved metabolic parameters in T2D.
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Affiliation(s)
- Fatemeh Bagheripour
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Sajad Jeddi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Khosrow Kashfi
- Department of Molecular, Cellular and Biomedical Sciences, Sophie Davis School of Biomedical Education, City University of New York School of Medicine, New York, New York, USA
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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Mosaad YO, Hussein MA, Ateyya H, Mohamed AH, Ali AA, Ramadan Youssuf A, Wink M, El-Kholy AA. Vanin 1 Gene Role in Modulation of iNOS/MCP-1/TGF-β1 Signaling Pathway in Obese Diabetic Patients. J Inflamm Res 2022; 15:6745-6759. [PMID: 36540060 PMCID: PMC9760040 DOI: 10.2147/jir.s386506] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/23/2022] [Indexed: 01/15/2024] Open
Abstract
INTRODUCTION Cysteamine, a powerful endogenous antioxidant, is produced mostly by the vanin-1 with pantetheinase activity. With regard to glycemic, inflammatory, and redox factors, the current study sought to evaluate the association between the expression of the vanin-1 gene, oxidative stress, and inflammatory and iNOS signaling pathway in obese diabetic patients. METHODS We enrolled 67 male subjects with an average age of 53.5 ± 5.0 years, divided into 4 groups according to the WHO guideline. We determined their plasma levels of glucose, insulin, IRI, HbA1c, TC, TG, HDL-C, TNF- α, MCP-1, TGF-β1, SOD, CAT, and TBARs, as well as expression of the iNOS and Vanin1 genes. RESULTS Overweight and obese class I and II diabetics had significantly higher levels of plasma glucose, insulin, HbA1c, TNF-α, MCP-1, TGF-β1, CAT, and TBAR as well as iNOS and vanin-1 gene expression compared to healthy control individuals. In addition, as compared to healthy control individuals, overweight obese class I and II diabetics' plasma HDL-C levels and blood SOD activity were significantly lower. In addition, ultrasound and computed tomography showed that the presence of a mild obscuring fatty liver with mild hepatic echogenicity appeared in overweight, class I and II obese diabetic patients. CONCLUSION These findings provide important information for understanding the correlation between Vanin 1 and glycemic, inflammatory, and redox factors in obese patients. Furthermore, US and CT analysis were performed to visualize the observed images of fatty liver due to obesity.
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Affiliation(s)
- Yasser O Mosaad
- Department of Pharmacy, Practice & Clinical Pharmacy, Faculty of Pharmacy, Future University, Cairo, Egypt
| | - Mohammed Abdalla Hussein
- Department of Biotechnology, Faculty of Applied Health Science, October 6th University, October 6th City, Egypt
| | - Hayam Ateyya
- Department of Medical Pharmacology, Faculty of Medicine, Cairo University, Cairo, Egypt
- Department of Pharmacy Practice and Clinical Pharmacy, Faculty of Pharmacy, Future University, Cairo, Egypt
| | - Ahmed H Mohamed
- Department of Radiology and Medical Imaging, Faculty of Applied Health Science Technology, October 6th University, October 6th City, Egypt
| | - Ali A Ali
- Food Sciences Department, Faculty of Agriculture, Ain Shams University, Cairo, Egypt
| | - Alaa Ramadan Youssuf
- Consultant and Head of Cardiology Department, AL-AHRAR Teaching Hospital, Zagazig University, Zagazig, Egypt
| | - Michael Wink
- Heidelberg University, Institute of Pharmacy and Molecular Biotechnology, Heidelberg, Germany
| | - Amal A El-Kholy
- Department of Clinical Pharmacy, Faculty of Pharmacy, Ain-Shams University, Cairo, Egypt
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Vilela VR, Samson N, Nachbar R, Perazza LR, Lachance G, Rokatoarivelo V, Centano-Baez C, Zancan P, Sola-Penna M, Bellmann K, Di Marzo V, Laplante M, Marette A. Adipocyte-specific Nos2 deletion improves insulin resistance and dyslipidemia through brown fat activation in diet-induced obese mice. Mol Metab 2022; 57:101437. [PMID: 35033724 PMCID: PMC8802131 DOI: 10.1016/j.molmet.2022.101437] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 12/22/2021] [Accepted: 01/03/2022] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE Inducible nitric oxide (NO) synthase (NOS2) is a well documented inflammatory mediator of insulin resistance in obesity. NOS2 expression is induced in both adipocytes and macrophages within adipose tissue during high-fat (HF)-induced obesity. METHODS Eight week old male mice with adipocyte selective deletion of the Nos2 gene (Nos2AD-KO) and their wildtype littermates (Nos2fl/fl) were subjected to chow or high-fat high-sucrose (HFHS) diet for 10 weeks followed by metabolic phenotyping and determination of brown adipose tissue (BAT) thermogenesis. The direct impact of NO on BAT mitochondrial respiration was also assessed in brown adipocytes. RESULTS Here, we show that HFHS-fed Nos2AD-KO mice had improved insulin sensitivity as compared to Nos2fl/fl littermates. Nos2AD-KO mice were also protected from HF-induced dyslipidemia and exhibited increased energy expenditure compared to Nos2fl/fl mice. This was linked to activation of BAT in HFHS-fed Nos2AD-KO mice as shown by increased Ucp1 and Ucp2 gene expression and augmented respiratory capacity of BAT mitochondria. Furthermore, mitochondrial respiration was inhibited by NO, or upon cytokine-induced NOS2 activation, but improved by NOS2 inhibition in brown adipocytes. CONCLUSIONS These results demonstrate a key role for adipocyte NOS2 in the development of obesity-linked insulin resistance and dyslipidemia, partly through NO dependent inhibition of BAT mitochondrial bioenergetics.
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Affiliation(s)
| | - Nolwenn Samson
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Renato Nachbar
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Lia Rossi Perazza
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Gabriel Lachance
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Volatiana Rokatoarivelo
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Carolina Centano-Baez
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Patricia Zancan
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Mauro Sola-Penna
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Kerstin Bellmann
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - Vincenzo Di Marzo
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada; Institute of Nutrition and Functional Foods, Centre NUTRISS, Université Laval, 2440 Boulevard Hochelaga Suite 1710, Québec, QC, G1V 0A6, Canada; Canada Excellence Research Chair Microbiome-Endocannabinoidome Axis in Metabolic Health (CERC-MEND)
| | - Mathieu Laplante
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada
| | - André Marette
- Quebec Heart & Lung Institute, Université Laval, 2725 Ch Ste-Foy, Québec, QC, G1V 4G5, Canada; Institute of Nutrition and Functional Foods, Centre NUTRISS, Université Laval, 2440 Boulevard Hochelaga Suite 1710, Québec, QC, G1V 0A6, Canada.
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Systemic Insulin Resistance and Metabolic Perturbations in Chow Fed Inducible Nitric Oxide Synthase Knockout Male Mice: Partial Reversal by Nitrite Supplementation. Antioxidants (Basel) 2020; 9:antiox9080736. [PMID: 32806494 PMCID: PMC7465804 DOI: 10.3390/antiox9080736] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023] Open
Abstract
iNOS, an important mediator of inflammation, has emerged as an important metabolic regulator. There are conflicting observations on the incidence of insulin resistance (IR) due to hyperglycemia/dyslipidemia in iNOS−/− mice. There are reports that high fat diet (HFD) fed mice exhibited no change, protection, or enhanced susceptibility to IR. Similar observations were also reported for low fat diet (LFD) fed KO mice. In the present study chow fed iNOS−/− mice were examined for the incidence of IR, and metabolic perturbations, and also for the effect of sodium nitrite supplementation (50 mg/L). In IR-iNOS−/− mice, we observed significantly higher body weight, BMI, adiposity, blood glucose, HOMA-IR, serum/tissue lipids, glucose intolerance, enhanced gluconeogenesis, and disrupted insulin signaling. Expression of genes involved in hepatic and adipose tissue lipid uptake, synthesis, oxidation, and gluconeogenesis was upregulated with concomitant downregulation of genes for hepatic lipid excretion. Nitrite supplementation restored NO levels, significantly improved systemic IR, glucose tolerance, and also reduced lipid accumulation by rescuing hepatic insulin sensitivity, glucose, and lipid homeostasis. Obesity, gluconeogenesis, and adipose tissue insulin signaling were only partially reversed in nitrite supplemented iNOS−/− mice. Our results thus demonstrate that nitrite supplementation to iNOS−/− mice improves insulin sensitivity and metabolic homeostasis, thus further highlighting the metabolic role of iNOS.
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Bahadoran Z, Mirmiran P, Ghasemi A. Role of Nitric Oxide in Insulin Secretion and Glucose Metabolism. Trends Endocrinol Metab 2020; 31:118-130. [PMID: 31690508 DOI: 10.1016/j.tem.2019.10.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2019] [Revised: 09/29/2019] [Accepted: 10/03/2019] [Indexed: 01/20/2023]
Abstract
Nitric oxide (NO) contributes to carbohydrate metabolism and decreased NO bioavailability is involved in the development of type 2 diabetes mellitus (T2DM). NO donors may improve insulin signaling and glucose homeostasis in T2DM and insulin resistance (IR), suggesting the potential clinical importance of NO-based interventions. In this review, site-specific roles of the NO synthase (NOS)-NO pathway in carbohydrate metabolism are discussed. In addition, the metabolic effects of physiological low levels of NO produced by constitutive NOS (cNOS) versus pathological high levels of NO produced by inducible NOS (iNOS) in pancreatic β-cells, adipocytes, hepatocytes, and skeletal muscle cells are summarized. A better understanding of the NOS-NO system in the regulation of glucose homeostasis can hopefully facilitate the development of new treatments for T2DM.
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Affiliation(s)
- Zahra Bahadoran
- Nutrition and Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Parvin Mirmiran
- Department of Clinical Nutrition and Human Dietetics, Faculty of Nutrition Sciences and Food Technology, National Nutrition and Food Technology Research Institute, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Asghar Ghasemi
- Endocrine Physiology Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Effects of different diets used in diet-induced obesity models on insulin resistance and vascular dysfunction in C57BL/6 mice. Sci Rep 2019; 9:19556. [PMID: 31862918 PMCID: PMC6925252 DOI: 10.1038/s41598-019-55987-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 11/22/2019] [Indexed: 11/11/2022] Open
Abstract
The aim of the present study was to compare different diets used to induce obesity in a head-to-head manner with a focus on insulin resistance and vascular dysfunction. Male C57BL/6J mice were put on standard chow diet (SCD), normal-fat diet (NFD), cafeteria diet (CAF) or high-fat diet (HFD) for 12 weeks starting at the age of 6 weeks. Both CAF and HFD led to obesity (weight gain of 179% and 194%, respectively), glucose intolerance and insulin resistance to a comparable extent. In aortas containing perivascular adipose tissue (PVAT), acetylcholine-induced vasodilation was best in the NFD group and worst in the CAF group. Reduced phosphorylation of endothelial nitric oxide synthase at serine 1177 was observed in both CAF and HFD groups. Plasma coagulation activity was highest in the HFD group and lowest in the SCD group. Even the NFD group had significantly higher coagulation activity than the SCD group. In conclusions, CAF and HFD are both reliable mouse diets in inducing visceral obesity, glucose intolerance and insulin resistance. CAF is more effective than HFD in causing PVAT dysfunction and vascular dysfunction, whereas hypercoagulability was mostly evident in the HFD group. Coagulation activity was higher in NFD than NCD group.
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Li P, Liu S, Lu M, Bandyopadhyay G, Oh D, Imamura T, Johnson AMF, Sears D, Shen Z, Cui B, Kong L, Hou S, Liang X, Iovino S, Watkins SM, Ying W, Osborn O, Wollam J, Brenner M, Olefsky JM. Hematopoietic-Derived Galectin-3 Causes Cellular and Systemic Insulin Resistance. Cell 2017; 167:973-984.e12. [PMID: 27814523 DOI: 10.1016/j.cell.2016.10.025] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Revised: 08/08/2016] [Accepted: 10/13/2016] [Indexed: 02/07/2023]
Abstract
In obesity, macrophages and other immune cells accumulate in insulin target tissues, promoting a chronic inflammatory state and insulin resistance. Galectin-3 (Gal3), a lectin mainly secreted by macrophages, is elevated in both obese subjects and mice. Administration of Gal3 to mice causes insulin resistance and glucose intolerance, whereas inhibition of Gal3, through either genetic or pharmacologic loss of function, improved insulin sensitivity in obese mice. In vitro treatment with Gal3 directly enhanced macrophage chemotaxis, reduced insulin-stimulated glucose uptake in myocytes and 3T3-L1 adipocytes and impaired insulin-mediated suppression of glucose output in primary mouse hepatocytes. Importantly, we found that Gal3 can bind directly to the insulin receptor (IR) and inhibit downstream IR signaling. These observations elucidate a novel role for Gal3 in hepatocyte, adipocyte, and myocyte insulin resistance, suggesting that Gal3 can link inflammation to decreased insulin sensitivity. Inhibition of Gal3 could be a new approach to treat insulin resistance.
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Affiliation(s)
- Pingping Li
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China; Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
| | - Shuainan Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Min Lu
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Diabetes Early Discovery, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Gautum Bandyopadhyay
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Dayoung Oh
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Takeshi Imamura
- Pharmacology, Department of Medicine, Shiga University of Medical Science, 1 Tsukinowa, Seta, Otsu-city, Shiga 520-2192, Japan
| | - Andrew M F Johnson
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Dorothy Sears
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Zhufang Shen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Bing Cui
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Lijuan Kong
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Shaocong Hou
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Xiao Liang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China; Diabetes Research Center of Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Salvatore Iovino
- Diabetes Early Discovery, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | | | - Wei Ying
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Olivia Osborn
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Joshua Wollam
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Martin Brenner
- Diabetes Early Discovery, Merck Research Laboratories, 33 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Jerrold M Olefsky
- Division of Endocrinology and Metabolism, UC, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA.
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Kanuri BN, Kanshana JS, Rebello SC, Pathak P, Gupta AP, Gayen JR, Jagavelu K, Dikshit M. Altered glucose and lipid homeostasis in liver and adipose tissue pre-dispose inducible NOS knockout mice to insulin resistance. Sci Rep 2017; 7:41009. [PMID: 28106120 PMCID: PMC5247703 DOI: 10.1038/srep41009] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Accepted: 12/14/2016] [Indexed: 12/15/2022] Open
Abstract
On the basis of diet induced obesity and KO mice models, nitric oxide is implied to play an important role in the initiation of dyslipidemia induced insulin resistance. However, outcomes using iNOS KO mice have so far remained inconclusive. The present study aimed to assess IR in iNOS KO mice after 5 weeks of LFD feeding by monitoring body composition, energy homeostasis, insulin sensitivity/signaling, nitrite content and gene expressions changes in the tissues. We found that body weight and fat content in KO mice were significantly higher while the respiratory exchange ratio (RER), volume of carbon dioxide (VCO2), and heat production were lower as compared to WT mice. Furthermore, altered systemic glucose tolerance, tissue insulin signaling, hepatic gluconeogenesis, augmented hepatic lipids, adiposity, as well as gene expression regulating lipid synthesis, catabolism and efflux were evident in iNOS KO mice. Significant reduction in eNOS and nNOS gene expression, hepatic and adipose tissue nitrite content, circulatory nitrite was also observed. Oxygen consumption rate of mitochondrial respiration has remained unaltered in KO mice as measured using extracellular flux analyzer. Our findings establish a link between the NO status with systemic and tissue specific IR in iNOS KO mice at 5 weeks.
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Affiliation(s)
- Babu Nageswararao Kanuri
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India.,Academy of Scientific and Innovative Research, New Delhi - 110001, India
| | - Jitendra S Kanshana
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Sanjay C Rebello
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Priya Pathak
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Anand P Gupta
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Jiaur R Gayen
- Pharmacokinetics and Metabolism Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Kumaravelu Jagavelu
- Pharmacology Division, CSIR-Central Drug Research Institute, Lucknow - 226031, India
| | - Madhu Dikshit
- Academy of Scientific and Innovative Research, New Delhi - 110001, India
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Jang JE, Ko MS, Yun JY, Kim MO, Kim JH, Park HS, Kim AR, Kim HJ, Kim BJ, Ahn YE, Oh JS, Lee WJ, Harris RA, Koh EH, Lee KU. Nitric Oxide Produced by Macrophages Inhibits Adipocyte Differentiation and Promotes Profibrogenic Responses in Preadipocytes to Induce Adipose Tissue Fibrosis. Diabetes 2016; 65:2516-28. [PMID: 27246913 DOI: 10.2337/db15-1624] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 05/18/2016] [Indexed: 11/13/2022]
Abstract
Fibrosis of adipose tissue induces ectopic fat accumulation and insulin resistance by inhibiting adipose tissue expandability. Mechanisms responsible for the induction of adipose tissue fibrosis may provide therapeutic targets but are poorly understood. In this study, high-fat diet (HFD)-fed wild-type (WT) and iNOS(-/-) mice were used to examine the relationship between nitric oxide (NO) produced by macrophages and adipose tissue fibrosis. In contrast to WT mice, iNOS(-/-) mice fed an HFD were protected from infiltration of proinflammatory macrophages and adipose tissue fibrosis. Hypoxia-inducible factor 1α (HIF-1α) protein level was increased in adipose tissue of HFD-fed WT mice, but not iNOS(-/-) mice. In contrast, the expression of mitochondrial biogenesis factors was decreased in HFD-fed WT mice, but not iNOS(-/-) mice. In studies with cultured cells, macrophage-derived NO decreased the expression of mitochondrial biogenesis factors, and increased HIF-1α protein level, DNA damage, and phosphorylated p53 in preadipocytes. By activating p53 signaling, NO suppressed peroxisome proliferator-activated receptor γ coactivator 1α expression, which induced mitochondrial dysfunction and inhibited preadipocyte differentiation in adipocytes. The effects of NO were blocked by rosiglitazone. The findings suggest that NO produced by macrophages induces mitochondrial dysfunction in preadipocytes by activating p53 signaling, which in turn increases HIF-1α protein level and promotes a profibrogenic response in preadipocytes that results in adipose tissue fibrosis.
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Affiliation(s)
- Jung Eun Jang
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Myoung Seok Ko
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Ji-Young Yun
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Mi-Ok Kim
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Jin Hee Kim
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Hye Sun Park
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Ah-Ram Kim
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Hyuk-Joong Kim
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Bum Joong Kim
- Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Young Eun Ahn
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Jin Sun Oh
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Woo Je Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Robert A Harris
- Richard L. Roudebush VA Medical Center and the Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN
| | - Eun Hee Koh
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
| | - Ki-Up Lee
- Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea Metabolism Research Unit, Asan Institute for Life Sciences, Seoul, Republic of Korea
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11
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Li P, Oh DY, Bandyopadhyay G, Lagakos WS, Talukdar S, Osborn O, Johnson A, Chung H, Maris M, Ofrecio JM, Taguchi S, Lu M, Olefsky JM. LTB4 promotes insulin resistance in obese mice by acting on macrophages, hepatocytes and myocytes. Nat Med 2015; 21:239-247. [PMID: 25706874 PMCID: PMC4429798 DOI: 10.1038/nm.3800] [Citation(s) in RCA: 229] [Impact Index Per Article: 25.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Accepted: 01/13/2015] [Indexed: 12/12/2022]
Abstract
Insulin resistance results from several pathophysiologic mechanisms, including chronic tissue inflammation and defective insulin signaling. We found that liver, muscle and adipose tissue exhibit higher levels of the chemotactic eicosanoid LTB4 in obese high-fat diet (HFD)-fed mice. Inhibition of the LTB4 receptor Ltb4r1, through either genetic or pharmacologic loss of function, led to an anti-inflammatory phenotype with protection from insulin resistance and hepatic steatosis. In vitro treatment with LTB4 directly enhanced macrophage chemotaxis, stimulated inflammatory pathways, reduced insulin-stimulated glucose uptake in L6 myocytes, and impaired insulin-mediated suppression of hepatic glucose output in primary mouse hepatocytes. This was accompanied by lower insulin-stimulated Akt phosphorylation and higher Irs-1/2 serine phosphorylation, and all of these events were dependent on Gαi and Jnk1, two downstream mediators of Ltb4r1 signaling. These observations elucidate a novel role of the LTB4-Ltb4r1 signaling pathway in hepatocyte and myocyte insulin resistance, and they show that in vivo inhibition of Ltb4r1 leads to robust insulin-sensitizing effects.
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Affiliation(s)
- Pingping Li
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Da Young Oh
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Gautam Bandyopadhyay
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - William S. Lagakos
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Saswata Talukdar
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Olivia Osborn
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Andrew Johnson
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Heekyung Chung
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Michael Maris
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Jachelle M. Ofrecio
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Sayaka Taguchi
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Min Lu
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Jerrold M. Olefsky
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
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12
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Lee JT, Pamir N, Liu NC, Kirk EA, Averill MM, Becker L, Larson I, Hagman DK, Foster-Schubert KE, van Yserloo B, Bornfeldt KE, LeBoeuf RC, Kratz M, Heinecke JW. Macrophage metalloelastase (MMP12) regulates adipose tissue expansion, insulin sensitivity, and expression of inducible nitric oxide synthase. Endocrinology 2014; 155:3409-20. [PMID: 24914938 PMCID: PMC4138576 DOI: 10.1210/en.2014-1037] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Macrophage metalloelastase, a matrix metallopeptidase (MMP12) predominantly expressed by mature tissue macrophages, is implicated in pathological processes. However, physiological functions for MMP12 have not been described. Because mRNA levels for the enzyme increase markedly in adipose tissue of obese mice, we investigated the role of MMP12 in adipose tissue expansion and insulin resistance. In humans, MMP12 expression correlated positively and significantly with insulin resistance, TNF-α expression, and the number of CD14(+)CD206(+) macrophages in adipose tissue. MMP12 was the most abundant matrix metallopeptidase detected by proteomic analysis of conditioned medium of M2 macrophages and dendritic cells. In contrast, it was detected only at low levels in bone marrow derived macrophages and M1 macrophages. When mice received a high-fat diet, adipose tissue mass increased and CD11b(+)F4/80(+)CD11c(-) macrophages accumulated to a greater extent in MMP12-deficient (Mmp12(-/-)) mice than in wild-type mice (Mmp12(+/+)). Despite being markedly more obese, fat-fed Mmp12(-/-) mice were more insulin sensitive than fat-fed Mmp12(+/+) mice. Expression of inducible nitric oxide synthase (Nos2) by Mmp12(-/-) macrophages was significantly impaired both in vivo and in vitro, suggesting that MMP12 might mediate nitric oxide production during inflammation. We propose that MMP12 acts as a double-edged sword by promoting insulin resistance while combatting adipose tissue expansion.
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Affiliation(s)
- Jung-Ting Lee
- Departments of Medicine (J.-T.L., N.P., N.-C.L., M.M.A., L.B., K.E.F.-S., B.V.Y., K.E.B., R.C.L., M.K., J.W.H.), Pathology (K.E.B.), and Epidemiology (E.A.K., M.K.), University of Washington, Seattle, Washington 98105; and Fred Hutchinson Cancer Research Center (D.K.H., M.K.), Public Health Sciences, Seattle, Washington 98103
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13
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Li P, Spann NJ, Kaikkonen MU, Lu M, Oh DY, Fox JN, Bandyopadhyay G, Talukdar S, Xu J, Lagakos WS, Patsouris D, Armando A, Quehenberger O, Dennis EA, Watkins SM, Auwerx J, Glass CK, Olefsky JM. NCoR repression of LXRs restricts macrophage biosynthesis of insulin-sensitizing omega 3 fatty acids. Cell 2013; 155:200-214. [PMID: 24074869 DOI: 10.1016/j.cell.2013.08.054] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 06/18/2013] [Accepted: 08/27/2013] [Indexed: 01/28/2023]
Abstract
Macrophage-mediated inflammation is a major contributor to obesity-associated insulin resistance. The corepressor NCoR interacts with inflammatory pathway genes in macrophages, suggesting that its removal would result in increased activity of inflammatory responses. Surprisingly, we find that macrophage-specific deletion of NCoR instead results in an anti-inflammatory phenotype along with robust systemic insulin sensitization in obese mice. We present evidence that derepression of LXRs contributes to this paradoxical anti-inflammatory phenotype by causing increased expression of genes that direct biosynthesis of palmitoleic acid and ω3 fatty acids. Remarkably, the increased ω3 fatty acid levels primarily inhibit NF-κB-dependent inflammatory responses by uncoupling NF-κB binding and enhancer/promoter histone acetylation from subsequent steps required for proinflammatory gene activation. This provides a mechanism for the in vivo anti-inflammatory insulin-sensitive phenotype observed in mice with macrophage-specific deletion of NCoR. Therapeutic methods to harness this mechanism could lead to a new approach to insulin-sensitizing therapies.
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Affiliation(s)
- Pingping Li
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Nathanael J Spann
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Minna U Kaikkonen
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Min Lu
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Da Young Oh
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Jesse N Fox
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Gautam Bandyopadhyay
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Saswata Talukdar
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Jianfeng Xu
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - William S Lagakos
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - David Patsouris
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Aaron Armando
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Oswald Quehenberger
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Edward A Dennis
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | | | - Johan Auwerx
- Laboratory of Integrative and Systems Physiology, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Christopher K Glass
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
| | - Jerrold M Olefsky
- Division of Endocrinology & Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, USA, 92093
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14
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Tsuchiya K, Westerterp M, Murphy AJ, Subramanian V, Ferrante AW, Tall AR, Accili D. Expanded granulocyte/monocyte compartment in myeloid-specific triple FoxO knockout increases oxidative stress and accelerates atherosclerosis in mice. Circ Res 2013; 112:992-1003. [PMID: 23420833 DOI: 10.1161/circresaha.112.300749] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
RATIONALE Increased neutrophil and monocyte counts are often associated with an increased risk of atherosclerosis, but their relationship to insulin sensitivity is unknown. OBJECTIVE To investigate the contribution of forkhead transcription factors (FoxO) in myeloid cells to neutrophil and monocyte counts, atherosclerosis, and systemic insulin sensitivity. METHODS AND RESULTS Genetic ablation of the 3 genes encoding FoxO isoforms 1, 3a, and 4, in myeloid cells resulted in an expansion of the granulocyte/monocyte progenitor compartment and was associated with increased atherosclerotic lesion formation in low-density lipoprotein receptor knockout mice. In vivo and ex vivo studies indicate that FoxO ablation in myeloid cells increased generation of reactive oxygen species. Accordingly, treatment with the antioxidant N-acetyl-l-cysteine reversed the phenotype, normalizing atherosclerosis. CONCLUSIONS Our data indicate that myeloid cell proliferation and oxidative stress can be modulated via the FoxO branch of insulin receptor signaling, highlighting a heretofore-unknown link between insulin sensitivity and leukocytosis that can affect the predisposition to atherosclerosis.
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Affiliation(s)
- Kyoichiro Tsuchiya
- Naomi Berrie Diabetes Center, 1150 St Nicholas Ave, Russ Berrie Pavilion Room 238, NY 10032, USA
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15
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Kraus RM, Houmard JA, Kraus WE, Tanner CJ, Pierce JR, Choi MD, Hickner RC. Obesity, insulin resistance, and skeletal muscle nitric oxide synthase. J Appl Physiol (1985) 2012; 113:758-65. [PMID: 22797309 DOI: 10.1152/japplphysiol.01018.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The molecular mechanisms responsible for impaired insulin action have yet to be fully identified. Rodent models demonstrate a strong relationship between insulin resistance and an elevation in skeletal muscle inducible nitric oxide synthase (iNOS) expression; the purpose of this investigation was to explore this potential relationship in humans. Sedentary men and women were recruited to participate (means ± SE: nonobese, body mass index = 25.5 ± 0.3 kg/m(2), n = 13; obese, body mass index = 36.6 ± 0.4 kg/m(2), n = 14). Insulin sensitivity was measured using an intravenous glucose tolerance test with the subsequent modeling of an insulin sensitivity index (S(I)). Skeletal muscle was obtained from the vastus lateralis, and iNOS, endothelial nitric oxide synthase (eNOS), and neuronal nitric oxide synthase (nNOS) content were determined by Western blot. S(I) was significantly lower in the obese compared with the nonobese group (~43%; P < 0.05), yet skeletal muscle iNOS protein expression was not different between nonobese and obese groups. Skeletal muscle eNOS protein was significantly higher in the nonobese than the obese group, and skeletal muscle nNOS protein tended to be higher (P = 0.054) in the obese compared with the nonobese group. Alternative analysis based on S(I) (high and low tertile) indicated that the most insulin-resistant group did not have significantly more skeletal muscle iNOS protein than the most insulin-sensitive group. In conclusion, human insulin resistance does not appear to be associated with an elevation in skeletal muscle iNOS protein in middle-aged individuals under fasting conditions.
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Affiliation(s)
- Raymond M Kraus
- Department of Kinesiology, East Carolina University, Greenville, North Carolina 27858, USA
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16
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Li P, Fan W, Xu J, Lu M, Yamamoto H, Auwerx J, Sears DD, Talukdar S, Oh D, Chen A, Bandyopadhyay G, Scadeng M, Ofrecio JM, Nalbandian S, Olefsky JM. Adipocyte NCoR knockout decreases PPARγ phosphorylation and enhances PPARγ activity and insulin sensitivity. Cell 2012; 147:815-26. [PMID: 22078880 DOI: 10.1016/j.cell.2011.09.050] [Citation(s) in RCA: 228] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/22/2011] [Accepted: 09/23/2011] [Indexed: 01/06/2023]
Abstract
Insulin resistance, tissue inflammation, and adipose tissue dysfunction are features of obesity and Type 2 diabetes. We generated adipocyte-specific Nuclear Receptor Corepressor (NCoR) knockout (AKO) mice to investigate the function of NCoR in adipocyte biology, glucose and insulin homeostasis. Despite increased obesity, glucose tolerance was improved in AKO mice, and clamp studies demonstrated enhanced insulin sensitivity in liver, muscle, and fat. Adipose tissue macrophage infiltration and inflammation were also decreased. PPARγ response genes were upregulated in adipose tissue from AKO mice and CDK5-mediated PPARγ ser-273 phosphorylation was reduced, creating a constitutively active PPARγ state. This identifies NCoR as an adaptor protein that enhances the ability of CDK5 to associate with and phosphorylate PPARγ. The dominant function of adipocyte NCoR is to transrepress PPARγ and promote PPARγ ser-273 phosphorylation, such that NCoR deletion leads to adipogenesis, reduced inflammation, and enhanced systemic insulin sensitivity, phenocopying the TZD-treated state.
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Affiliation(s)
- Pingping Li
- Division of Endocrinology and Metabolism, Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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17
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Roe ND, Ren J. Akt2 knockout mitigates chronic iNOS inhibition-induced cardiomyocyte atrophy and contractile dysfunction despite persistent insulin resistance. Toxicol Lett 2011; 207:222-31. [PMID: 21964073 DOI: 10.1016/j.toxlet.2011.09.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 09/11/2011] [Accepted: 09/12/2011] [Indexed: 11/18/2022]
Abstract
Increased levels of inducible nitric oxide synthase (iNOS) during cardiac stress such as ischemia-reperfusion, sepsis and hypertension may display both beneficial and detrimental roles in cardiac contractile performance. However, the precise role of iNOS in the maintenance of cardiac contractile function remains elusive. This study was designed to determine the impact of chronic iNOS inhibition on cardiac contractile function and the underlying mechanism involved with a special focus on the NO downstream signaling molecule Akt. Male C57 or Akt2 knockout [Akt2(-/-)] mice were injected with the specific iNOS inhibitor 1400W (2 mg/kg/d) or saline for 7 days. Both 1400W and Akt2 knockout dampened glucose and insulin tolerance without additive effects. Treatment of 1400W decreased heart and liver weights as well as cardiomyocyte cross-sectional area in C57 but not Akt2 knockout mice. 1400W but not Akt2 knockout compromised cardiomyocyte mechanical properties including decreased peak shortening and maximal velocity of shortening/relengthening, prolonged relengthening duration, reduced intracellular Ca(2+) release and decay rate, the effects of which were ablated or attenuated by Akt2 knockout. Akt2 knockout but not 1400W increased the levels of intracellular Ca(2+) regulatory proteins including SERCA2a and phospholamban phosphorylation. 1400W reduced the level of anti-apoptotic protein Bcl-2, the effect of which was unaffected by Akt2 knockout. Neither 1400W nor Akt2 knockout significantly affected ER stress, autophagy, the post-insulin receptor signaling Akt, GSK3β and AMPK, as well as the stress signaling IκB, JNK, ERK and p38 with the exception of elevated IκB phosphorylation with jointed effect of 1400W and Akt2 knockout. Taken together, these data indicated that an essential role of iNOS in the maintenance of cardiac morphology and function possibly through an Akt2-dependent mechanism.
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Affiliation(s)
- Nathan D Roe
- Division of Pharmaceutical Sciences & Center for Cardiovascular Research and Alternative Medicine, University of Wyoming College of Health Sciences, Laramie, WY 82071, USA
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18
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Lu M, Sarruf DA, Talukdar S, Sharma S, Li P, Bandyopadhyay G, Nalbandian S, Fan W, Gayen JR, Mahata SK, Webster NJ, Schwartz MW, Olefsky JM. Brain PPAR-γ promotes obesity and is required for the insulin-sensitizing effect of thiazolidinediones. Nat Med 2011; 17:618-22. [PMID: 21532596 PMCID: PMC3380629 DOI: 10.1038/nm.2332] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 02/15/2011] [Indexed: 01/28/2023]
Abstract
In adipose tissue, muscle, liver and macrophages, signaling by the nuclear receptor peroxisome proliferator-activated receptor-γ (PPAR-γ) is a determinant of insulin sensitivity and this receptor mediates the insulin-sensitizing effects of thiazolidinediones (TZDs). As PPAR-γ is also expressed in neurons, we generated mice with neuron-specific Pparg knockout (Pparg brain knockout (BKO)) to determine whether neuronal PPAR-γ signaling contributes to either weight gain or insulin sensitivity. During high-fat diet (HFD) feeding, food intake was reduced and energy expenditure increased in Pparg-BKO mice compared to Pparg(f/f) mice, resulting in reduced weight gain. Pparg-BKO mice also responded better to leptin administration than Pparg(f/f) mice. When treated with the TZD rosiglitazone, Pparg-BKO mice were resistant to rosiglitazone-induced hyperphagia and weight gain and, relative to rosiglitazone-treated Pparg(f/f) mice, experienced only a marginal improvement in glucose metabolism. Hyperinsulinemic euglycemic clamp studies showed that the increase in hepatic insulin sensitivity induced by rosiglitazone treatment during HFD feeding was completely abolished in Pparg-BKO mice, an effect associated with the failure of rosiglitazone to improve liver insulin receptor signal transduction. We conclude that excess weight gain induced by HFD feeding depends in part on the effect of neuronal PPAR-γ signaling to limit thermogenesis and increase food intake. Neuronal PPAR-γ signaling is also required for the hepatic insulin sensitizing effects of TZDs.
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Affiliation(s)
- Min Lu
- Department of Medicine, University of California-San Diego (UCSD), San Diego, California, USA
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