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Kaplanian M, Philippe C, Eid SA, Hackl MT, Metz M, Beghini M, Luca AC, Kautzky-Willer A, Scherer T, Fürnsinn C. Deciphering metformin action in obese mice: A critical re-evaluation of established protocols. Metabolism 2022; 128:154956. [PMID: 34953917 DOI: 10.1016/j.metabol.2021.154956] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 11/25/2021] [Accepted: 12/11/2021] [Indexed: 02/09/2023]
Abstract
BACKGROUND AND PURPOSE Despite extensive efforts and a plethora of suggested targets and pathways, the mechanism via which metformin lowers blood glucose remains obscure. Obstacles that hamper progress in understanding metformin action include unexplained discrepancies between preclinical models and patients. PROCEDURES We treated obese male C57BL/6J mice fed high fat diet with metformin provided in the form of a single dose, daily intraperitoneal injections, admixture to drinking water, or continuous infusion via intraperitoneal minipumps. RESULTS The results suggest several superimposed components, via which metformin acts on blood glucose. These include (i) marked glucose lowering shortly after dosing, which fades rapidly with the decrease in metformin concentrations in plasma and liver, but could, at least to a major extent, rely on the mechanism also accounting for metformin's therapeutic action in humans; (ii) indirect action via reduced weight gain, which might be responsible for glucose lowering observed in many previous rodent studies; and (iii) deterioration of glucose homeostasis by prolonged treatment that can be unmasked by avoidance of dosing shortly before measuring blood glucose in combination with exclusion of weight-related actions via restricted feeding of the control mice. CONCLUSIONS Our work raises the question whether elucidation of metformin's anti-diabetic mechanism(s) in rodent experiments may in the past have been hampered by failure to mimic clinical circumstances, as caused by insufficient consideration of pharmacokinetics and multiplicity of involved actions.
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Affiliation(s)
- Mairam Kaplanian
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Cecile Philippe
- Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Sameer Abu Eid
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Martina T Hackl
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Matthäus Metz
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Marianna Beghini
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Andreea C Luca
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Alexandra Kautzky-Willer
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Thomas Scherer
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria
| | - Clemens Fürnsinn
- Division of Endocrinology & Metabolism, Department of Medicine III, Medical University of Vienna, Währinger Gürtel 18-20, 1090 Vienna, Austria.
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Roy B, Palaniyandi SS. Tissue-specific role and associated downstream signaling pathways of adiponectin. Cell Biosci 2021; 11:77. [PMID: 33902691 PMCID: PMC8073961 DOI: 10.1186/s13578-021-00587-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022] Open
Abstract
According to the World Health Organization, metabolic syndrome (MetS) can be defined as a pathological condition characterized by abdominal obesity, insulin resistance, hypertension, and hyperlipidemia. The incidence of MetS keeps rising, as at least 35% of the USA population suffers from MetS. One of the worst comorbidities of metabolic syndrome are cardiovascular diseases that significantly amplifies the mortality associated with this syndrome. There is an urgent need to understand the pathophysiology of MetS to find novel diagnosis, treatment and management to mitigate the MetS and associated complications. Altered circulatory adiponectin levels have been implicated in MetS. Adiponectin has numerous biologic functions including antioxidative, anti-nitrative, anti-inflammatory, and cardioprotective effects. Being a pleiotropic hormone of multiple tissues, tissue-specific key signaling pathways of adiponectin will help finding specific target/s to blunt the pathophysiology of metabolic syndrome and associated disorders. The purpose of this review is to elucidate tissue-specific signaling pathways of adiponectin and possibly identify potential therapeutic targets for MetS as well as to evaluate the potential of adiponectin as a biomarker/therapeutic option in MetS.
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Affiliation(s)
- Bipradas Roy
- Division of Hypertension and Vascular Research, Department of Internal Medicine, Henry Ford Health System, Integrative Biosciences Center (IBio), Room #3402, 6135 Woodward, Detroit, MI 48202 USA
- Department of Physiology, Wayne State University, Detroit, MI 48202 USA
| | - Suresh Selvaraj Palaniyandi
- Division of Hypertension and Vascular Research, Department of Internal Medicine, Henry Ford Health System, Integrative Biosciences Center (IBio), Room #3402, 6135 Woodward, Detroit, MI 48202 USA
- Department of Physiology, Wayne State University, Detroit, MI 48202 USA
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Li B, Po SS, Zhang B, Bai F, Li J, Qin F, Liu N, Sun C, Xiao Y, Tu T, Zhou S, Liu Q. Metformin regulates adiponectin signalling in epicardial adipose tissue and reduces atrial fibrillation vulnerability. J Cell Mol Med 2020; 24:7751-7766. [PMID: 32441464 PMCID: PMC7348162 DOI: 10.1111/jcmm.15407] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 03/31/2020] [Accepted: 04/22/2020] [Indexed: 12/26/2022] Open
Abstract
Epicardial adipose tissue (EAT) remodelling is closely related to the pathogenesis of atrial fibrillation (AF). We investigated whether metformin (MET) prevents AF‐dependent EAT remodelling and AF vulnerability in dogs. A canine AF model was developed by 6‐week rapid atrial pacing (RAP), and electrophysiological parameters were measured. Effective refractory periods (ERP) were decreased in the left and right atrial appendages as well as in the left atrium (LA) and right atrium (RA). MET attenuated the RAP‐induced increase in ERP dispersion, cumulative window of vulnerability, AF inducibility and AF duration. RAP increased reactive oxygen species (ROS) production and nuclear factor kappa‐B (NF‐κB) phosphorylation; up‐regulated interleukin‐6 (IL‐6), tumour necrosis factor‐α (TNF‐α) and transforming growth factor‐β1 (TGF‐β1) levels in LA and EAT; decreased peroxisome proliferator‐activated receptor gamma (PPARγ) and adiponectin (APN) expression in EAT and was accompanied by atrial fibrosis and adipose infiltration. MET reversed these alterations. In vitro, lipopolysaccharide (LPS) exposure increased IL‐6, TNF‐α and TGF‐β1 expression and decreased PPARγ/APN expression in 3T3‐L1 adipocytes, which were all reversed after MET administration. Indirect coculture of HL‐1 cells with LPS‐stimulated 3T3‐L1 conditioned medium (CM) significantly increased IL‐6, TNF‐α and TGF‐β1 expression and decreased SERCA2a and p‐PLN expression, while LPS + MET CM and APN treatment alleviated the inflammatory response and sarcoplasmic reticulum Ca2+ handling dysfunction. MET attenuated the RAP‐induced increase in AF vulnerability, remodelling of atria and EAT adipokines production profiles. APN may play a key role in the prevention of AF‐dependent EAT remodelling and AF vulnerability by MET.
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Affiliation(s)
- Biao Li
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Sunny S Po
- Heart Rhythm Institute and Department of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Baojian Zhang
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China.,Department of Cardiology, the Affiliated Chinese Medicine Hospital of Xinjiang Medical University, Urumqi City, Xinjiang Province, China
| | - Fan Bai
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Jiayi Li
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Fen Qin
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Na Liu
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Chao Sun
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Yichao Xiao
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Tao Tu
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Shenghua Zhou
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
| | - Qiming Liu
- Department of Cardiology/Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China
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Mrabti HN, El Abbes Faouzi M, Mayuk FM, Makrane H, Limas-Nzouzi N, Dibong SD, Cherrah Y, Elombo FK, Gressier B, Desjeux JF, Eto B. Arbutus unedo L., (Ericaceae) inhibits intestinal glucose absorption and improves glucose tolerance in rodents. JOURNAL OF ETHNOPHARMACOLOGY 2019; 235:385-391. [PMID: 30742883 DOI: 10.1016/j.jep.2019.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 02/07/2019] [Accepted: 02/08/2019] [Indexed: 06/09/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Arbutus unedo L., (Ericaceae) is one of the most traditional plants commonly used to treat diabetes in people living in Eastern Morocco region particularly in Taza and Beni Mellal. AIM OF THE STUDY The aim of the study was to find if there is a scientific support to the ethnopharmacological relevance use of Arbutus unedo L., roots bark (AU) to treat diabetes. MATERIALS AND METHODS We studied the effects of crude aqueous extract of AU on intestinal glucose absorption using short-circuit current technique in vitro and oral glucose tolerance test in vivo. RESULTS The aqueous extract of AU (10 µg/mL to 1 mg/mL) induced concentration-dependent inhibition of sodium-dependent glucose transport across isolated mouse jejunum. The maximal inhibition was obtained with 1 mg/mL, which exhibited more than 80% of the Phloridzin inhibition with an IC50 close to 216 µg/mL. A 6-week AU ingestion (2 g/(kg day)), improved oral glucose tolerance as efficiently as metformin (300 mg/(kg day)). Arbutus unedo L. and metformin also reduced body weight. CONCLUSIONS Arbutus unedo L. roots bark aqueous extract directly inhibited the electrogenic intestinal absorption of glucose in vitro. In addition it improved oral glucose tolerance and lowered body weight in rats after chronic oral administration in vivo. These results add a scientific support to the ethnopharmacological relevance use of Arbutus unedo L. roots bark to treat diabetes.
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Affiliation(s)
- Hanae Naceiri Mrabti
- Laboratory of Pharmacology and Toxicology, Research Team of Bio Pharmaceutical and Toxicological Analyzes, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat BP 6203, Morocco
| | - Moulay El Abbes Faouzi
- Laboratory of Pharmacology and Toxicology, Research Team of Bio Pharmaceutical and Toxicological Analyzes, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat BP 6203, Morocco
| | - François Massako Mayuk
- Etobiotech Cameroun and Laboratory of Biology and Physiology of Plant Organisms, Department of Plant Biology, University of Douala, Cameroon; Laboratoires TBC, Faculty of Pharmaceutical and Biological Sciences, Lille, France
| | - Hanane Makrane
- Laboratoires TBC, Faculty of Pharmaceutical and Biological Sciences, Lille, France
| | - Nicolas Limas-Nzouzi
- Laboratoires TBC, Faculty of Pharmaceutical and Biological Sciences, Lille, France
| | - Siegfried Didier Dibong
- Etobiotech Cameroun and Laboratory of Biology and Physiology of Plant Organisms, Department of Plant Biology, University of Douala, Cameroon
| | - Yahia Cherrah
- Laboratory of Pharmacology and Toxicology, Research Team of Bio Pharmaceutical and Toxicological Analyzes, Faculty of Medicine and Pharmacy, Mohammed V University, Rabat BP 6203, Morocco
| | | | - Bernard Gressier
- Laboratory of Pharmacology, Pharmacokinetics and Clinical Pharmacy, Faculty of Pharmaceutical and Biological Sciences, Lille, France
| | | | - Bruno Eto
- Laboratoires TBC, Faculty of Pharmaceutical and Biological Sciences, Lille, France.
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Liu Y, Vu V, Sweeney G. Examining the Potential of Developing and Implementing Use of Adiponectin-Targeted Therapeutics for Metabolic and Cardiovascular Diseases. Front Endocrinol (Lausanne) 2019; 10:842. [PMID: 31920962 PMCID: PMC6918867 DOI: 10.3389/fendo.2019.00842] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 11/19/2019] [Indexed: 02/06/2023] Open
Abstract
Cardiometabolic diseases encompass those affecting the heart and vasculature as well as other metabolic problems, such as insulin resistance, diabetes, and non-alcoholic fatty liver disease. These diseases tend to have common risk factors, one of which is impaired adiponectin action. This may be due to reduced bioavailability of the hormone or resistance to its effects on target tissues. A strong negative correlation between adiponectin levels and cardiometabolic diseases has been well-documented and research shown that adiponectin has cardioprotective, insulin sensitizing and direct beneficial metabolic effects. Thus, therapeutic approaches to enhance adiponectin action are widely considered to be desirable. The complexity of adiponectin structure and function has so far made progress in this area less than ideal. In this article we will review the effects and mechanism of action of adiponectin on cardiometabolic tissues, identify scenarios where enhancing adiponectin action would be of clinical value and finally discuss approaches via which this can be achieved.
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Affiliation(s)
- Ying Liu
- Metabolic Disease Research Division, iCarbonX Co. Ltd., Shenzhen, China
- *Correspondence: Ying Liu
| | - Vivian Vu
- Department of Biology, York University, Toronto, ON, Canada
| | - Gary Sweeney
- Department of Biology, York University, Toronto, ON, Canada
- Gary Sweeney
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Manganese supplementation increases adiponectin and lowers ICAM-1 and creatinine blood levels in Zucker type 2 diabetic rats, and downregulates ICAM-1 by upregulating adiponectin multimerization protein (DsbA-L) in endothelial cells. Mol Cell Biochem 2017; 429:1-10. [PMID: 28083716 DOI: 10.1007/s11010-016-2931-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 12/23/2016] [Indexed: 12/15/2022]
Abstract
Blood and tissue levels of manganese (Mn) are lower in type 2 diabetic and atherosclerosis patients compared with healthy subjects. Adiponectin has anti-diabetic and anti-atherogenic properties. Impairment in Disulfide bond A-like protein (DsbA-L) is associated with low adiponectin levels and diabetes. This study investigates the hypothesis that the beneficial effects of Mn supplementation are mediated by adiponectin and DsbA-L. At 6 weeks of age, Male Zucker diabetic fatty rats (ZDF) were randomly divided into two groups: diabetic controls and Mn-supplemented diabetic rats. Each rat was supplemented with Mn (D+Mn, 16 mg/kg BW) or water (placebo, D+P) daily for 7 weeks by oral gavage. For cell culture studies, Human Umbilical Vein Endothelial Cells (HUVEC) or 3T3L1 adipocytes were pretreated with Mn (0-10 µM MnCl2) for 24 h, followed by high glucose (HG, 25 mM) or normal glucose (5 mM) exposure for another 24 h. Mn supplementation resulted in higher adiponectin (p = 0.01), and lower ICAM-1 (p = 0.04) and lower creatinine (p = 0.04) blood levels compared to those in control ZDF rats. Mn-supplemented rats also caused reduced oxidative stress (ROS) and NADPH oxidase, and higher DsbA-L expression in the liver (p = 0.03) of ZDF rats compared to those in livers of control rats; however, Fe levels in liver were lower but not significant (p = 0.08). Similarly, treatment with high glucose (25 mM) caused a decrease in DsbA-L, which was prevented by Mn supplementation in HUVEC and adipocytes. Mechanistic studies with DsbA-L siRNA showed that the beneficial effects of Mn supplementation on ROS, NOX4, and ICAM-1 expression were abolished in DsbA-L knock-down HUVEC. These studies demonstrate that DsbA-L-linked adiponectin mediates the beneficial effects observed with Mn supplementation and provides evidence for a novel mechanism by which Mn supplementation can increase adiponectin and reduce the biomarkers of endothelial dysfunction in diabetes.
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7
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Woodward L, Akoumianakis I, Antoniades C. Unravelling the adiponectin paradox: novel roles of adiponectin in the regulation of cardiovascular disease. Br J Pharmacol 2016; 174:4007-4020. [PMID: 27629236 DOI: 10.1111/bph.13619] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/19/2016] [Accepted: 08/31/2016] [Indexed: 02/07/2023] Open
Abstract
Adipose tissue (AT) has recently been identified as a dynamic endocrine organ secreting a wide range of adipokines. Adiponectin is one such hormone, exerting endocrine and paracrine effects on the cardiovascular system. At a cellular and molecular level, adiponectin has anti-inflammatory, antioxidant and anti-apoptotic roles, thereby mitigating key mechanisms underlying cardiovascular disease (CVD) pathogenesis. However, adiponectin expression in human AT as well as its circulating levels are increased in advanced CVD states, and it is actually considered by many as a 'rescue hormone'. Due to the complex mechanisms regulating adiponectin's biosynthesis in the human AT, measurement of its levels as a biomarker in CVD is highly controversial, given that adiponectin exerts protective effects on the cardiovascular system but at the same time its increased levels flag advanced CVD. In this review article, we present the involvement of adiponectin in CVD pathogenesis and we discuss its role as a clinical biomarker. LINKED ARTICLES This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.
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Affiliation(s)
- Lavinia Woodward
- Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Ioannis Akoumianakis
- Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Charalambos Antoniades
- Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
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8
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Tirmenstein M, Horvath J, Graziano M, Mangipudy R, Dorr T, Colman K, Zinker B, Kirby M, Cheng PTW, Patrone L, Kozlosky J, Reilly TP, Wang V, Janovitz E. Utilization of the Zucker Diabetic Fatty (ZDF) Rat Model for Investigating Hypoglycemia-related Toxicities. Toxicol Pathol 2015; 43:825-37. [PMID: 26085543 DOI: 10.1177/0192623315581020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Glucokinase (GK) catalyzes the initial step in glycolysis and is a key regulator of glucose homeostasis. Therefore, glucokinase activators (GKa) have potential benefit in treating type 2 diabetes. Administration of a Bristol-Myers Squibb GKa (BMS-820132) to healthy euglycemic Sprague-Dawley (SD) rats and beagle dogs in 1 mo toxicology studies resulted in marked and extended hypoglycemia with associated clinical signs of toxicity and degenerative histopathological changes in the stomach, sciatic nerve, myocardium, and skeletal muscles at exposures comparable to those expected at therapeutic clinical exposures. To investigate whether these adverse effects were secondary to exaggerated pharmacology (prolonged hypoglycemia), BMS-820132 was administered daily to male Zucker diabetic fatty (ZDF) rats for 1 mo. ZDF rats are markedly hyperglycemic and insulin resistant. BMS-820132 did not induce hypoglycemia, clinical signs of hypoglycemia, or any of the histopathologic adverse effects observed in the 1 mo toxicology studies at exposures that exceeded those observed in SD rats and dogs. This indicates that the toxicity observed in euglycemic animals was secondary to the exaggerated pharmacology of potent GK activation. This study indicates that ZDF rats, with conventional toxicity studies, are a useful disease model for testing antidiabetic agents and determining toxicities that are independent of prolonged hypoglycemia.
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Affiliation(s)
- Mark Tirmenstein
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Joseph Horvath
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Michael Graziano
- Bristol-Myers Squibb, Drug Safety Evaluation, Princeton, New Jersey, USA
| | - Raja Mangipudy
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Thomas Dorr
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Karyn Colman
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA Present affiliation: Novartis Institutes for BioMedical Research, East Hanover, New Jersey, USA
| | - Bradley Zinker
- Bristol-Myers Squibb, Discovery Biology, Pennington, New Jersey, USA
| | - Mark Kirby
- Bristol-Myers Squibb, Discovery Biology, Pennington, New Jersey, USA Present affiliation: Lilly China Research and Development Center, Shanghai, China
| | - Peter T W Cheng
- Bristol-Myers Squibb, Discovery Chemistry, Pennington, New Jersey, USA
| | - Laura Patrone
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - John Kozlosky
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Timothy P Reilly
- Bristol-Myers Squibb, Exploratory Clinical and Translational Research, Princeton, New Jersey, USA
| | - Victor Wang
- Bristol-Myers Squibb, Drug Safety Evaluation, New Brunswick, New Jersey, USA
| | - Evan Janovitz
- Bristol-Myers Squibb, Discovery Toxicology, Pennington, New Jersey, USA
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Lustig Y, Barhod E, Ashwal-Fluss R, Gordin R, Shomron N, Baruch-Umansky K, Hemi R, Karasik A, Kanety H. RNA-binding protein PTB and microRNA-221 coregulate AdipoR1 translation and adiponectin signaling. Diabetes 2014; 63:433-45. [PMID: 24130336 DOI: 10.2337/db13-1032] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Adiponectin receptor 1 (AdipoR1) mediates adiponectin's pleiotropic effects in muscle and liver and plays an important role in the regulation of insulin resistance and diabetes. Here, we demonstrate a pivotal role for microRNA-221 (miR-221) and the RNA-binding protein polypyrimidine tract-binding protein (PTB) in posttranscriptional regulation of AdipoR1 during muscle differentiation and in obesity. RNA-immunoprecipitation and luciferase reporter assays illustrated that both PTB and miR-221 bind AdipoR1-3'UTR and cooperatively inhibit AdipoR1 translation. Depletion of PTB or miR-221 increased, while overexpression of these factors decreased, AdipoR1 protein synthesis in both muscle and liver cells. During myogenesis, downregulation of PTB and miR-221 robustly induced AdipoR1 translation, providing a mechanism for enhanced AdipoR1 protein expression and activation in differentiated muscle cells. In addition, since both PTB and miR-221 are upregulated in liver and muscle of genetic and dietary mouse models of obesity, this novel translational mechanism may be at least partly responsible for the reduction in AdipoR1 protein levels in obesity. These findings highlight the importance of translational control in regulating AdipoR1 protein expression and adiponectin signaling. Given that adiponectin is reduced in obesity, induction of AdipoR1 could potentially enhance adiponectin beneficial effects and ameliorate insulin resistance and diabetes.
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Affiliation(s)
- Yaniv Lustig
- Institute of Endocrinology, Chaim Sheba Medical Center, Tel-Hashomer, Israel
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10
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Potential utility of sodium selenate as an adjunct to metformin in treating type II diabetes mellitus in rats: a perspective on protein tyrosine phosphatase. BIOMED RESEARCH INTERNATIONAL 2013; 2013:231378. [PMID: 24106697 PMCID: PMC3784083 DOI: 10.1155/2013/231378] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 08/12/2013] [Indexed: 12/14/2022]
Abstract
Metformin is widely regarded as the standard first-line antidiabetic agent, in terms of efficacy and safety profiles. However, in most patients with type II diabetes mellitus (T2DM), it was found that metformin alone is not enough to adequately control hyperglycemia. Thus, we designed this study with the aim to investigate the effect of sodium selenate, a protein tyrosine phosphatase (PTP) inhibitor, individually and as an adjunct to metformin, on a rat model that simulates the metabolic characteristics of human T2DM. T2DM model was achieved by feeding the rats with high-fat, high-fructose diet (HFFD) for 8 weeks followed by a low dose of streptozotocin (STZ) (35 mg/kg/day, i.p.). Changes in serum glucose, insulin, adiponectin, homeostasis model assessment of insulin resistance (HOMA-IR) index, and the lipid profile were assessed. In addition, the level of reduced glutathione (GSH) and the activity of PTP were determined in the liver. Results showed that the addition of sodium selenate to metformin was able to restore hepatic GSH back to normal levels. Also, this combination therapy corrected the altered serum total cholesterol (TC), triglycerides (TG), and adiponectin levels. In conclusion, additive therapeutic effect was recorded when sodium selenate was used as an adjunct to metformin.
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Fibrate therapy and circulating adiponectin concentrations: A systematic review and meta-analysis of randomized placebo-controlled trials. Atherosclerosis 2013; 230:110-20. [DOI: 10.1016/j.atherosclerosis.2013.06.026] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 06/24/2013] [Accepted: 06/29/2013] [Indexed: 12/12/2022]
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12
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Benoit C, Ould-Hamouda H, Crepin D, Gertler A, Amar L, Taouis M. Early leptin blockade predisposes fat-fed rats to overweight and modifies hypothalamic microRNAs. J Endocrinol 2013; 218:35-47. [PMID: 23576026 DOI: 10.1530/joe-12-0561] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Perinatal leptin impairment has long-term consequences on energy homeostasis leading to body weight gain. The underlying mechanisms are still not clearly established. We aimed to analyze the long-term effects of early leptin blockade. In this study, newborn rats received daily injection of a pegylated rat leptin antagonist (pRLA) or saline from day 2 (d2) to d13 and then body weight gain, insulin/leptin sensitivity, and expression profile of microRNAs (miRNAs) at the hypothalamic level were determined at d28, d90, or d153 (following 1 month of high-fat diet (HFD) challenge). We show that pRLA treatment predisposes rats to overweight and promotes leptin/insulin resistance in both hypothalamus and liver at adulthood. pRLA treatment also modifies the hypothalamic miRNA expression profile at d28 leading to the upregulation of 34 miRNAs and the downregulation of four miRNAs. For quantitative RT-PCR confirmation, we show the upregulation of rno-miR-10a at d28 and rno-miR-200a, rno-miR-409-5p, and rno-miR-125a-3p following HFD challenge. Finally, pRLA treatment modifies the expression of genes involved in energy homeostasis control such as UCPs and AdipoRs. In pRLA rat muscle, Ucp2/3 and Adipor1/r2 are upregulated at d90. In liver, pRLA treatment upregulates Adipor1/r2 following HFD challenge. These genes are known to be involved in insulin resistance and type 2 diabetes. In conclusion, we demonstrate that the impairment of leptin action in early life promotes insulin/leptin resistance and modifies the hypothalamic miRNA expression pattern in adulthood, and finally, this study highlights the potential link between hypothalamic miRNA expression pattern and insulin/leptin responsiveness.
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Affiliation(s)
- Charlotte Benoit
- Neuroendocrinologie Moléculaire de la Prise Alimentaire, University of Paris-Sud, UMR 8195, Orsay F-91405, France
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Schmid PM, Resch M, Schach C, Birner C, Riegger GA, Luchner A, Endemann DH. Antidiabetic treatment restores adiponectin serum levels and APPL1 expression, but does not improve adiponectin-induced vasodilation and endothelial dysfunction in Zucker diabetic fatty rats. Cardiovasc Diabetol 2013; 12:46. [PMID: 23497197 PMCID: PMC3606629 DOI: 10.1186/1475-2840-12-46] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Accepted: 03/12/2013] [Indexed: 01/21/2023] Open
Abstract
Background Adiponectin is able to induce NO-dependent vasodilation in Zucker lean (ZL) rats, but this effect is clearly alleviated in their diabetic littermates, the Zucker diabetic fatty (ZDF) rats. ZDF rats also exhibit hypoadiponectinemia and a suppressed expression of APPL1, an adaptor protein of the adiponectin receptors, in mesenteric resistance arteries. Whether an antidiabetic treatment can restore the vasodilatory effect of adiponectin and improve endothelial function in diabetes mellitus type 2 is not known. Methods During our animal experiment from week 11 to 22 in each case seven ZDF rats received an antidiabetic treatment with either insulin (ZDF+I) or metformin (ZDF+M). Six normoglycemic ZL and six untreated ZDF rats served as controls. Blood glucose was measured at least weekly and serum adiponectin levels were quantified via ELISA in week 11 and 22. The direct vasodilatory response of their isolated mesenteric resistance arteries to adiponectin as well as the endothelium-dependent and -independent function was evaluated in a small vessel myograph. Additionally, the expression of different components of the adiponectin signaling pathway in the resistance arteries was quantified by real-time RT-PCR. Results In ZDF rats a sufficient blood glucose control could only be reached by treatment with insulin, but both treatments restored the serum levels of adiponectin and the expression of APPL1 in small resistance arteries. Nevertheless, both therapies were not able to improve the vasodilatory response to adiponectin as well as endothelial function in ZDF rats. Concurrently, a downregulation of the adiponectin receptors 1 and 2 as well as endothelial NO-synthase expression was detected in insulin-treated ZDF rats. Metformin-treated ZDF rats showed a reduced expression of adiponectin receptor 2. Conclusions An antidiabetic treatment with either insulin or metformin in ZDF rats inhibits the development of hypoadiponectinemia and downregulation of APPL1 in mesenteric resistance arteries, but is not able to improve adiponectin induced vasodilation and endothelial dysfunction. This is possibly due to alterations in the expression of adiponectin receptors and eNOS.
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Affiliation(s)
- Peter M Schmid
- Klinik und Poliklinik für Innere Medizin 2, Franz-Josef-Strauss Allee 11, University of Regensburg, Regensburg, 93042, Germany.
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Burlet E, Jain SK. Manganese supplementation reduces high glucose-induced monocyte adhesion to endothelial cells and endothelial dysfunction in Zucker diabetic fatty rats. J Biol Chem 2013; 288:6409-16. [PMID: 23329836 DOI: 10.1074/jbc.m112.447805] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Endothelial dysfunction is a hallmark of increased vascular inflammation, dyslipidemia, and the development of atherosclerosis in diabetes. Previous studies have reported lower levels of Mn(2+) in the plasma and lymphocytes of diabetic patients and in the heart and aortic tissue of patients with atherosclerosis. This study examines the hypothesis that Mn(2+) supplementation can reduce the markers/risk factors of endothelial dysfunction in type 2 diabetes. Human umbilical vein endothelial cells (HUVECs) were cultured with or without Mn(2+) supplementation and then exposed to high glucose (HG, 25 mm) to mimic diabetic conditions. Mn(2+) supplementation caused a reduction in monocyte adhesion to HUVECs treated with HG or MCP-1. Mn(2+) also inhibited ROS levels, MCP-1 secretion, and ICAM-1 up-regulation in HUVECs treated with HG. Silencing studies using siRNA against MnSOD showed that similar results were observed in MnSOD knockdown HUVECs following Mn(2+) supplementation, suggesting that the effect of manganese on monocyte adhesion to endothelial cells is mediated by ROS and ICAM-1, but not MnSOD. To validate the relevance of our findings in vivo, Zucker diabetic fatty rats were gavaged daily with water (placebo) or MnCl2 (16 mg/kg of body weight) for 7 weeks. When compared with placebo, Mn(2+)-supplemented rats showed lower blood levels of ICAM-1 (17%, p < 0.04), cholesterol (25%, p < 0.05), and MCP-1 (28%, p = 0.25). These in vitro and in vivo studies demonstrate that Mn(2+) supplementation can down-regulate ICAM-1 expression and ROS independently of MnSOD, leading to a decrease in monocyte adhesion to endothelial cells, and therefore can lower the risk of endothelial dysfunction in diabetes.
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Affiliation(s)
- Elodie Burlet
- Department of Pediatrics and Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, Shreveport, Louisiana 71130, USA
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Fellmann L, Nascimento AR, Tibiriça E, Bousquet P. Murine models for pharmacological studies of the metabolic syndrome. Pharmacol Ther 2012. [PMID: 23178510 DOI: 10.1016/j.pharmthera.2012.11.004] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Metabolic syndrome has been described as the association of insulin resistance, hypertension, hyperlipidemia and obesity. Its prevalence increased dramatically, mainly in developed countries. Animal models are essential to understand the pathophysiology of this syndrome. This review presents the murine models of metabolic syndrome the most often used in pharmacological studies. The most common metabolic syndrome models exhibit a non-functional leptin pathway, or metabolic disorders induced by high fat diets. In a first part, and after a short introduction on leptin, its receptor and mechanism of action, we provide a detailed description of each model: SHROB, SHHF, JCR:LA-cp, Zucker, ZDF, Wistar Ottawa Karlsburg W, and Otsuka Long-Evans Tokushima Fatty rats, ob/ob, db/db, agouti yellow and Mc4R KO mice. The second part of this review is dedicated to metabolic syndrome models obtained by high fat feeding.
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Affiliation(s)
- Lyne Fellmann
- Laboratory of Neurobiology and Cardiovascular Pharmacology, EA4438, Faculty of Medicine, University of Strasbourg, France
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Samah M, El-Aidy AER, Tawfik MK, Ewais MMS. Evaluation of the antifibrotic effect of fenofibrate and rosiglitazone on bleomycin-induced pulmonary fibrosis in rats. Eur J Pharmacol 2012; 689:186-93. [PMID: 22659583 DOI: 10.1016/j.ejphar.2012.05.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 05/16/2012] [Accepted: 05/22/2012] [Indexed: 11/26/2022]
Abstract
Idiopathic pulmonary fibrosis is the most prevalent chronic fibrosing lung disease. Peroxisome proliferator-activated receptors-gamma agonists provide potential therapy for fibrotic diseases of the lung. Peroxisome proliferator-activated receptors-alpha agonists may be helpful in the treatment of lung inflammatory diseases, however their therapeutic potential on the "fibro-proliferative" process and extracellular matrix accumulation in idiopathic pulmonary fibrosis has been less well studied. So, the present study was conducted to evaluate the anti-fibrotic effects of fenofibrate (peroxisome proliferator-activated receptors-alpha agonist) alone and in combination with rosiglitazone (peroxisome proliferator-activated receptors-gamma agonist) on lung injury induced by bleomycin administration. Oral administration of either rosiglitazone (5 mg/kg/d) or fenofibrate (100 mg/kg/d) for 14 days, attenuated the severity of bleomycin-induced lung injury and fibrosis through decreasing lung water contents, lung fibrotic grading, lung hydroxyproline contents and lung transforming growth factor-beta1 levels; with no significant difference between them. Combined low doses of rosiglitazone (1 mg/kg/d) and fenofibrate (30 mg/kg/d) provided more benefits than full separate doses of each on the deleterious effects accompanied bleomycin administration. These findings suggested the potential use of peroxisome proliferator-activated receptors-alpha ligands as anti-fibrotic agents in lung fibrosis. Additionally, the concurrent administration of fenofibrate and rosiglitazone in low doses has synergistic effect and enhanced the beneficial effects afforded by either fenofibrate or rosiglitazone.
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Affiliation(s)
- M Samah
- Department of Pharmacology, Faculty of Medicine, Suez Canal University, Ismailia 41522, Egypt
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Asensio-López MC, Lax A, Pascual-Figal DA, Valdés M, Sánchez-Más J. Metformin protects against doxorubicin-induced cardiotoxicity: involvement of the adiponectin cardiac system. Free Radic Biol Med 2011; 51:1861-71. [PMID: 21907790 DOI: 10.1016/j.freeradbiomed.2011.08.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Revised: 08/17/2011] [Accepted: 08/17/2011] [Indexed: 11/23/2022]
Abstract
Doxorubicin has cardiotoxic effects that limit its clinical benefit in cancer patients. Metformin exerts cardioprotective actions via AMP-activated protein kinase (AMPK) and increases the expression of adiponectin and its receptors (adipoR1 and adipoR2) in skeletal muscle and adipose tissue, but its effect on cardiac tissue is still unknown. This work aimed to study whether metformin exerts any protective action against the cardiotoxicity of doxorubicin and whether the cardiac system of adiponectin is involved in any such action. The addition of doxorubicin (5μM) to adult mouse cardiomyocytes (HL-1 cell line) induced apoptosis, which was characterized by a loss of cell viability, activation of caspases, and fragmentation of the genetic material. Doxorubicin treatment also caused a decrease in the activity of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase. Pretreatment with metformin (4mM, 24h) provided protection against doxorubicin-induced damage. This pretreatment significantly increased cell viability, attenuated the activation of caspases and the fragmentation of genetic material, and restored the antioxidant activity. In addition, metformin up-regulated the expression of adiponectin and its receptors, adipoR1 and adipoR2, in cardiomyocytes. In contrast, silencing either adipoR1 or adipoR2 with siRNA inhibited the AMPK activation and the protective effects of metformin. Taken together, these results demonstrate that metformin protects cardiomyocytes from doxorubicin-induced damage and that the cardiac adiponectin system plays an important role in this protective action.
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Affiliation(s)
- Mari C Asensio-López
- Heart Failure Unit, Cardiology Department, University Hospital Virgen de la Arrixaca, 30120 Murcia, Spain
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Globular and full-length adiponectin induce NO-dependent vasodilation in resistance arteries of Zucker lean but not Zucker diabetic fatty rats. Am J Hypertens 2011; 24:270-7. [PMID: 21151013 DOI: 10.1038/ajh.2010.239] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND Adiponectin increases nitric oxide (NO) production in endothelial cell cultures and is reduced in the circulation of obese and diabetic patients, but its functional effect on resistance arteries is not yet studied in detail. METHODS We assessed the direct vasodilatory response of isolated mesenteric resistance arteries of Zucker diabetic fatty (ZDF) rats and Zucker lean (ZL) rats to globular adiponectin (gAd) and full-length adiponectin (fAd) and tested the effect of additional reactive oxygen species (ROS) inhibitors in vitro. Serum adiponectin and insulin levels were measured by ELISA. The mRNA expressions of the adiponectin receptors and the downstream signaling molecules adaptor protein, phosphotyrosine interaction, PH domain and leucine zipper containing 1 (APPL1), adaptor protein, phosphotyrosine interaction, PH domain and leucine zipper containing 2 (APPL2), and endothelial NO synthase (eNOS) in mesenteric resistance arteries were quantified by real-time reverse transcriptase PCR. RESULTS Both gAd and fAd induced a relevant dose-dependent vasodilation in ZL, but not in hypoadiponectinemic ZDF rats. This effect was totally blunted by L-nitroarginine-methyl-ester indicating NO dependency. The addition of ROS inhibitors could not improve the vasodilatory effect of adiponectin. Vasodilatory response to acetylcholine was reduced in ZDF rats, which could not be enhanced by low-dose adiponectin. Adiponectin receptor 1 (AdipoR1) was higher expressed than adiponectin receptor 2 (AdipoR2) with no significant differences between both animal groups, but APPL1 was significantly decreased in ZDF rats. The eNOS expression was not significantly different between ZL and ZDF rats. CONCLUSIONS Adiponectin exerts a NO-dependent vasodilation in resistance arteries of normoglycemic ZL rats, but not diabetic ZDF rats. This may contribute to endothelial dysfunction in ZDF rats. Alterations in the expression of APPL1 may be involved in the observed insensitivity to adiponectin in ZDF rats.
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ATF3 negatively regulates adiponectin receptor 1 expression. Biochem Biophys Res Commun 2010; 400:72-7. [PMID: 20696134 DOI: 10.1016/j.bbrc.2010.08.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 08/03/2010] [Indexed: 01/31/2023]
Abstract
Adiponectin is an adipocyte-derived hormone that has antidiabetic and antiatherogenic effects through two membrane receptors, adiponectin receptor 1 (AdipoR1) and adiponectin receptor 2 (AdipoR2). Although it has been reported that the expression of AdipoR1 and AdipoR2 is regulated under physiological and pathophysiological states, their regulation is largely unknown. Previously, we demonstrated that endoplasmic reticulum (ER) stress or obesity-inducible ATF3 negatively regulates the expression of adiponectin and AdipoR2. Here, we investigated the regulation of another adiponectin receptor, AdipoR1 by ATF3, to determine if ATF3 may contribute to impairment of adiponectin signaling by repressing the expression of both adiponectin and adiponectin receptors. We found that treatment with thapsigargin, a stimulator of ATF3 expression as an inducer of ER stress, decreased AdipoR1 expression in insulin-sensitive cells (HepG2, C2C12) and insulin secreting cells (MIN6N8). Furthermore, overexpression of lentivirus carrying-ATF3 decreased AdipoR1 expression in those cells, demonstrating that ATF3 downregulates AdipoR1 expression. Next, we investigated the effects of ATF3 on human AdipoR1 promoter activity and identified an ATF3-responsive region in the promoter. Both thapsigargin treatment and ATF3 expression repressed AdipoR1 promoter activity. Transfection studies using mutant constructs containing 5'-deletions in the human AdipoR1 promoter revealed that putative ATF/CRE site is located between the -248 and -224, TGACGCGG. Chromatin immunoprecipitation assay demonstrated that ATF3 directly binds to human AdipoR1 promoter spanning from -248 to -224. Finally, deletion of the putative ATF/CRE site abrogated ATF3-mediated transrepression of the AdipoR1 promoter. Importantly, ATF3 expression was increased in hyperglycemia or TNF-α-treated C2C12 cells in which AdipoR1 expression was decreased, suggesting that ATF3 may contribute to downregulation of AdipoR1 by hyperglycemia and TNF-α. Collectively, these results demonstrate that ATF3 negatively regulates human AdipoR1 expression via binding to an ATF3-responsive region in the promoter, which plays an important role in attenuation of adiponectin signaling and induction of insulin resistance.
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Yunoki K, Renaguli M, Kinoshita M, Matsuyama H, Mawatari S, Fujino T, Kodama Y, Sugiyama M, Ohnishi M. Dietary sphingolipids ameliorate disorders of lipid metabolism in Zucker fatty rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:7030-7035. [PMID: 20443604 DOI: 10.1021/jf100722f] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Dietary sphingolipids (SL) inhibit colon carcinogenesis, reduce serum cholesterol, and improve skin barrier function and are considered to be "functional lipids". For comparative determination of the effects of SL with different chemical compositions on lipid metabolism and its related hepatic gene expression, Zucker fatty rats were fed pure sphingomyelin (SM) of animal origin and glucosylceramide (GC) of plant origin. After 45 days, the SM and GC diets led to significant reductions in hepatic lipid and plasma non-HDL cholesterol. Both SM and GC diets decreased plasma insulin levels, whereas only the GC diet increased the plasma adiponectin level. Hepatic gene expression analysis revealed increased expression of adiponectin receptor 2 (Adipor2), peroxisome proliferator-activated receptor alpha (PPARalpha), and pyruvate dehydrogenase kinase 4 (Pdk4). However, expression of stearoyl CoA desaturase (Scd1) was significantly decreased. These results suggest that dietary SL, even of different origins and chemical compositions, may prevent fatty liver and hypercholesterolemia through improvement of adiponectin signaling and consequent increases in insulin sensitivity.
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Affiliation(s)
- Keita Yunoki
- Department of Food Science, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan
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Bauer S, Weigert J, Neumeier M, Wanninger J, Schäffler A, Luchner A, Schnitzbauer AA, Aslanidis C, Buechler C. Low-abundant adiponectin receptors in visceral adipose tissue of humans and rats are further reduced in diabetic animals. Arch Med Res 2010; 41:75-82. [PMID: 20470935 DOI: 10.1016/j.arcmed.2010.02.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Accepted: 01/12/2010] [Indexed: 12/22/2022]
Abstract
BACKGROUND AND AIMS Adipose tissue is an endocrine organ that releases various proteins that may also exert autocrine/paracrine effects. The antidiabetic adipokine adiponectin acts through two receptors, AdipoR1 and AdipoR2, but so far mainly mRNA expression has been measured in adipocytes and adipose tissues. Therefore, we aimed to analyze AdipoR1 and AdipoR2 proteins in adipocytes and paired samples of subcutaneous and visceral adipocytes/adipose tissue. METHODS AdipoR1 and AdipoR2 mRNA and protein expression were determined in adipocytes and paired samples of subcutaneous and visceral adipose tissue of humans and rats. RESULTS AdipoR1 and AdipoR2 proteins were similarly abundant in preadipocytes and mature adipocytes despite an induction of mRNA expression during differentiation. Differentiation of 3T3-L1 cells in the presence of palmitic acid did not alter adiponectin receptor proteins but metformin and fenofibrate upregulated AdipoR2 within 24 h of incubation. AdipoR2 protein was significantly lower in human visceral compared to subcutaneous fat, and both receptors were reduced in visceral adipocytes. In rat tissues both receptors were reduced in visceral fat. In diabetic animals AdipoR2 protein, but not mRNA, was lower in both fat depots compared to similarly obese rats with normal glucose disposal. AdipoR1 was only reduced in subcutaneous adipose tissue of diabetic animals where mRNA expression was induced. CONCLUSIONS These data indicate that mRNA expression is not suitable to predict adiponectin receptor protein. Low adiponectin receptors in visceral adipocytes and adipose tissue and further suppression in adipose tissue of insulin-resistant animals indicate disturbed adiponectin bioactivity.
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Affiliation(s)
- Sabrina Bauer
- Department of Internal Medicine I, Regensburg University Hospital, D-93042 Regensburg, Germany
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Hwang IK, Kim IY, Joo EJ, Shin JH, Choi JW, Won MH, Yoon YS, Seong JK. Metformin Normalizes Type 2 Diabetes-Induced Decrease in Cell Proliferation and Neuroblast Differentiation in the Rat Dentate Gyrus. Neurochem Res 2010; 35:645-50. [DOI: 10.1007/s11064-009-0115-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/11/2009] [Indexed: 11/27/2022]
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Meddah B, Ducroc R, El Abbes Faouzi M, Eto B, Mahraoui L, Benhaddou-Andaloussi A, Martineau LC, Cherrah Y, Haddad PS. Nigella sativa inhibits intestinal glucose absorption and improves glucose tolerance in rats. JOURNAL OF ETHNOPHARMACOLOGY 2009; 121:419-424. [PMID: 19061948 DOI: 10.1016/j.jep.2008.10.040] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 10/13/2008] [Accepted: 10/25/2008] [Indexed: 05/27/2023]
Abstract
AIM OF THE STUDY Nigella sativa L. (Ranunculaceae) seeds have been used traditionally for centuries, notably for treating diabetes. MATERIALS AND METHODS We studied the effects of the crude aqueous extract of Nigella sativa seeds on intestinal glucose absorption in vitro using a short-circuit current technique and in vivo using an oral glucose tolerance test. RESULTS The aqueous extract of Nigella sativa (0.1 pg/ml to 100 ng/ml) exerted dose-dependent inhibition of sodium-dependent glucose transport across isolated rat jejunum. Maximal inhibition exceeded 80% and IC50 was close to 10 pg/ml. An oral glucose tolerance test was carried out in rats after the initial dose and after a 6-week treatment of Nigella sativa (2 g/(kg day)), and compared to metformin (300 mg/(kg day)). Chronic Nigella sativa treatment improved glucose tolerance as efficiently as metformin. Nigella sativa and metformin also reduced body weight without any toxic effect. CONCLUSIONS To our knowledge, this is the first demonstration that Nigella sativa directly inhibits the electrogenic intestinal absorption of glucose in vitro. Together with the observed improvement of glucose tolerance and body weight in rats after chronic oral administration in vivo, these effects further validate the traditional use of Nigella sativa seeds against diabetes.
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Affiliation(s)
- Bouchra Meddah
- Laboratory of Pharmacology and Toxicology, Faculty of Medicine and Pharmacy, Université Mohammed V-Souissi, Rabat, Morocco
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