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Pavithra V, Janhavi P, Natasha J, Neelam R, Mrityunjaya M, Selvi MK, Ravindra PV. A blend of cod liver oil and virgin coconut oil improves the endurance performance in mice. SPORT SCIENCES FOR HEALTH 2022. [DOI: 10.1007/s11332-022-01001-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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Ebihara C, Aizawa-Abe M, Zhao M, Gumbilai V, Ebihara K. Different sites of actions make different responses to thiazolidinediones between mouse and rat models of fatty liver. Sci Rep 2022; 12:449. [PMID: 35013417 PMCID: PMC8748829 DOI: 10.1038/s41598-021-04036-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/30/2021] [Indexed: 02/06/2023] Open
Abstract
Therapeutic approach for NAFLD is limited and there are no approved drugs. Pioglitazone (PGZ), a thiazolidinedione (TZD) that acts via peroxisome proliferator activated receptor gamma (PPARγ) is the only agent that has shown consistent benefit and efficacy in clinical trials. However, the mechanism of its therapeutic effect on NAFLD remains unclear. The poor understanding may be due to problems with mouse, a species most used for animal experiments. TZDs exacerbate fatty liver in mouse models while they improve it in rat models like in human patients. Therefore, we compared the effects of TZDs including PGZ and rosiglitazone (RGZ) in ob/ob mice and Lepmkyo/Lepmkyo rats, models of leptin-deficient obesity, and A-ZIP/F-1 mice and seipin knockout (SKO) rats, models of generalized lipodystrophy. Pparg mRNA expression was markedly upregulated in fatty livers of mouse models while it was unchanged in rat models. TZDs exacerbated fatty liver in ob/ob and A-ZIP/F-1 mice, improved it in Lepmkyo/Lepmkyo rats and showed no effect in SKO rats. Gene expression analyses of Pparg and its target gene, Fsp27 revealed that PPARγ in the adipose tissue is the exclusive therapeutic target of TZDs in rats but PPARγ in the liver in addition to the adipose tissue is also a major site of actions for TZDs in mice. Although the response to TZDs in mice is the complete opposite of that in human patients, no report has pointed out the problem with TZD studies using mouse models so far. The present study might provide useful suggestions in research on TZDs.
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Affiliation(s)
- Chihiro Ebihara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi, 329-0498, Japan
| | - Megumi Aizawa-Abe
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan
| | - Mingming Zhao
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Valentino Gumbilai
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ken Ebihara
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan.
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Jichi Medical University School of Medicine, 3311-1 Yakushiji, Shimotsuke-shi, Tochigi, 329-0498, Japan.
- Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan.
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Abstract
This review highlights molecular mechanisms of anti-inflammatory and protective
effects of the nuclear transcription factor, peroxisome proliferator-activated
receptor γ (PPARγ) in vascular tissue. PPARγ is an ubiquitously expressed
nuclear factor, and well-studied in adipose tissue and inflammatory cells.
Additionally, beneficial effects of vascular PPARγ’s on atherosclerosis and
vascular remodeling/dysfunction have been reported although the detailed
mechanism remains to be completely elucidated. Clinical and basic studies have
shown that the synthetic PPARγ ligands, thiazolidinediones (TZDs), have
protective effects against cardiovascular diseases such as atherosclerosis.
Recent studies utilizing genetic tools suggested that those protective effects
of TZDs on cardiovascular diseases are not due to a consequence of improvement
of insulin resistance, but may be due to a direct effect on PPARγ’s in vascular
endothelial and smooth muscle cells. In this review, we discuss proposed
mechanisms by which the vascular PPARγ regulates vascular inflammation and
remodeling/dysfunction especially in smooth muscle cells.
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Affiliation(s)
- Masashi Mukohda
- Laboratory of Veterinary Pharmacology, Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Ehime 794-8555, Japan
| | - Hiroshi Ozaki
- Laboratory of Veterinary Pharmacology, Faculty of Veterinary Medicine, Okayama University of Science, Imabari, Ehime 794-8555, Japan
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Wittrisch S, Klöting N, Mörl K, Chakaroun R, Blüher M, Beck-Sickinger AG. NPY 1R-targeted peptide-mediated delivery of a dual PPARα/γ agonist to adipocytes enhances adipogenesis and prevents diabetes progression. Mol Metab 2019; 31:163-180. [PMID: 31918918 PMCID: PMC6931124 DOI: 10.1016/j.molmet.2019.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/31/2019] [Accepted: 11/10/2019] [Indexed: 12/12/2022] Open
Abstract
Objective PPARα/γ dual agonists have been in clinical development for the treatment of metabolic diseases including type 2 diabetes and dyslipidemia. However, severe adverse side effects led to complications in clinical trials. As most of the beneficial effects rely on the compound activity in adipocytes, the selective targeting of this cell type is a cutting-edge strategy to develop safe anti-diabetic drugs. The goal of this study was to strengthen the adipocyte-specific uptake of the PPARα/γ agonist tesaglitazar via NPY1R-mediated internalization. Methods NPY1R-preferring peptide tesaglitazar-[F7, P34]-NPY (tesa-NPY) was synthesized by a combination of automated SPPS and manual couplings. Following molecular and functional analyses for proof of concept, cell culture experiments were conducted to monitor the effects on adipogenesis. Mice treated with peptide drug conjugates or vehicle either by gavage or intraperitoneal injection were characterized phenotypically and metabolically. Histological analysis and transcriptional profiling of the adipose tissue were performed. Results In vitro studies revealed that the tesaglitazar-[F7, P34]-NPY conjugate selectively activates PPARγ in NPY1R-expressing cells and enhances adipocyte differentiation and adiponectin expression in adipocyte precursor cells. In vivo studies using db/db mice demonstrated that the anti-diabetic activity of the peptide conjugate is as efficient as that of systemically administered tesaglitazar. Additionally, tesa-NPY induces adipocyte differentiation in vivo. Conclusions The use of the tesaglitazar-[F7, P34]-NPY conjugate is a promising strategy to apply the beneficial PPARα/γ effects in adipocytes while potentially omitting adverse effects in other tissues. Tesaglitazar-NPY targets adipocytes via NPY1R receptor-mediated internalization. Peptide-drug conjugate is specifically delivered to NPY1R-expressing cells. Release of tesaglitazar in adipocytes activates PPARγ. Drug delivery enhances adipocyte differentiation and adiponectin expression. Peptide conjugate exhibits antidiabetic activity in vivo.
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Affiliation(s)
- Stefanie Wittrisch
- Universität Leipzig, Institute of Biochemistry, Brüderstraße 34, 04103 Leipzig, Germany
| | - Nora Klöting
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany.
| | - Karin Mörl
- Universität Leipzig, Institute of Biochemistry, Brüderstraße 34, 04103 Leipzig, Germany
| | - Rima Chakaroun
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany; Department of Medicine, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany
| | - Matthias Blüher
- Helmholtz Institute for Metabolic, Obesity, and Vascular Research (HI-MAG) of the Helmholtz Zentrum München at the University of Leipzig and University Hospital Leipzig, Ph.-Rosenthal-Str. 27, 04103 Leipzig, Germany; Department of Medicine, University of Leipzig, Liebigstraße 20, 04103 Leipzig, Germany.
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5
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Bayindir-Buchhalter I, Wolff G, Lerch S, Sijmonsma T, Schuster M, Gronych J, Billeter AT, Babaei R, Krunic D, Ketscher L, Spielmann N, Hrabe de Angelis M, Ruas JL, Müller-Stich BP, Heikenwalder M, Lichter P, Herzig S, Vegiopoulos A. Cited4 is a sex-biased mediator of the antidiabetic glitazone response in adipocyte progenitors. EMBO Mol Med 2019; 10:emmm.201708613. [PMID: 29973382 PMCID: PMC6079535 DOI: 10.15252/emmm.201708613] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Most antidiabetic drugs treat disease symptoms rather than adipose tissue dysfunction as a key pathogenic cause in the metabolic syndrome and type 2 diabetes. Pharmacological targeting of adipose tissue through the nuclear receptor PPARg, as exemplified by glitazone treatments, mediates efficacious insulin sensitization. However, a better understanding of the context‐specific PPARg responses is required for the development of novel approaches with reduced side effects. Here, we identified the transcriptional cofactor Cited4 as a target and mediator of rosiglitazone in human and murine adipocyte progenitor cells, where it promoted specific sets of the rosiglitazone‐dependent transcriptional program. In mice, Cited4 was required for the proper induction of thermogenic expression by Rosi specifically in subcutaneous fat. This phenotype had high penetrance in females only and was not evident in beta‐adrenergically stimulated browning. Intriguingly, this specific defect was associated with reduced capacity for systemic thermogenesis and compromised insulin sensitization upon therapeutic rosiglitazone treatment in female but not male mice. Our findings on Cited4 function reveal novel unexpected aspects of the pharmacological targeting of PPARg.
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Affiliation(s)
- Irem Bayindir-Buchhalter
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
| | - Gretchen Wolff
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
| | - Sarah Lerch
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
| | - Tjeerd Sijmonsma
- Division Chronic Inflammation and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Maximilian Schuster
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
| | - Jan Gronych
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Adrian T Billeter
- Department of General, Visceral, and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Rohollah Babaei
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
| | - Damir Krunic
- Light Microscopy Facility, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Lars Ketscher
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Nadine Spielmann
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Hrabe de Angelis
- German Mouse Clinic, Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany.,Chair of Experimental Genetics, School of Life Science Weihenstephan, Technische Universität München, Freising, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Jorge L Ruas
- Department of Physiology and Pharmacology, Molecular and Cellular Exercise Physiology, Karolinska Institutet, Stockholm, Sweden
| | - Beat P Müller-Stich
- Department of General, Visceral, and Transplantation Surgery, University of Heidelberg, Heidelberg, Germany
| | - Mathias Heikenwalder
- Division Chronic Inflammation and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Peter Lichter
- Division of Molecular Genetics, German Cancer Research Center (DKFZ), German Cancer Consortium (DKTK), Heidelberg, Germany
| | - Stephan Herzig
- Helmholtz Center Munich, Institute for Diabetes and Cancer IDC, Neuherberg, Germany.,Joint Heidelberg-IDC Translational Diabetes Program, Heidelberg University Hospital, Heidelberg, Germany
| | - Alexandros Vegiopoulos
- DKFZ Junior Group Metabolism and Stem Cell Plasticity, German Cancer Research Center, Heidelberg, Germany
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6
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Xu W, Zhou H, Xuan H, Saha P, Wang G, Chen W. Novel metabolic disorders in skeletal muscle of Lipodystrophic Bscl2/Seipin deficient mice. Mol Cell Endocrinol 2019; 482:1-10. [PMID: 30521848 PMCID: PMC6340772 DOI: 10.1016/j.mce.2018.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/03/2018] [Accepted: 12/03/2018] [Indexed: 01/23/2023]
Abstract
Bscl2-/- mice recapitulate many of the major metabolic manifestations in Berardinelli-Seip congenital lipodystrophy type 2 (BSCL2) individuals, including lipodystrophy, hepatosteatosis, muscular hypertrophy, and insulin resistance. Metabolic defects in Bscl2-/- mice with regard to glucose and lipid metabolism in skeletal muscle have never been investigated. Here, we identified Bscl2-/- mice displayed reduced intramyocellular triglyceride (IMTG) content but increased glycogen storage predominantly in oxidative type I soleus muscle (SM). These changes were associated with increased incomplete fatty acid oxidation and glycogen synthesis. Interestingly, SM in Bscl2-/- mice demonstrated a fasting duration induced insulin sensitivity which was further confirmed by hyperinsulinemic-euglycemic clamp in SM of overnight fasted Bscl2-/- mice but reversed by raising circulating NEFA levels through intralipid infusion. Furthermore, mice with skeletal muscle-specific inactivation of BSCL2 manifested no changes in muscle deposition of lipids and glycogen, suggesting BSCL2 does not play a cell-autonomous role in muscle lipid and glucose homeostasis. Our study uncovers a novel link between muscle metabolic defects and insulin resistance, and underscores an important role of circulating NEFA in regulating oxidative muscle insulin signaling in BSCL2 lipodystrophy.
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Affiliation(s)
- Wenqiong Xu
- Department of Endocrinology and Metabolism, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, PR China; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA
| | - Hongyi Zhou
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA
| | - Hongzhuan Xuan
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA; School of Life Science, Liaocheng University, Liaocheng, Shandong Province, 252059, PR China
| | - Pradip Saha
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Gongxian Wang
- Department of Urology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi Province, 330006, PR China.
| | - Weiqin Chen
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, 30912, USA.
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Chen L, Zhou L, Yu P, Fang F, Jiang L, Fei J, Xiao H, Wang J. Methamphetamine exposure upregulates the amyloid precursor protein and hyperphosphorylated tau expression: The roles of insulin signaling in SH-SY5Y cell line. J Toxicol Sci 2019; 44:493-503. [PMID: 31270305 DOI: 10.2131/jts.44.493] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Lingling Chen
- Children’s Hospital of Nanjing Medical University, China
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Li Zhou
- Children’s Hospital of Nanjing Medical University, China
| | - Pengfei Yu
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Fangfang Fang
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
- Community Health Service Center of Rong Xiang Street, China
| | - Lei Jiang
- Department of Emergency Medicine, the First Affiliated Hospital of Nanjing Medical University, China
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Jian Fei
- Children’s Hospital of Nanjing Medical University, China
| | - Hang Xiao
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
| | - Jun Wang
- Key Lab of Modern Toxicology (NJMU), Ministry of Education; Department of Toxicology, School of Public Health, Nanjing Medical University, China
- China International Cooperation Center for Environment and Human Health, China
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Ge X, Pan P, Jing J, Hu X, Chen L, Qiu X, Ma R, Jueraitetibaike K, Huang X, Yao B. Rosiglitazone ameliorates palmitic acid-induced cytotoxicity in TM4 Sertoli cells. Reprod Biol Endocrinol 2018; 16:98. [PMID: 30333041 PMCID: PMC6192158 DOI: 10.1186/s12958-018-0416-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 10/05/2018] [Indexed: 12/17/2022] Open
Abstract
The Sertoli cell is the only somatic cell within the seminiferous tubules, and is vital for testis development and spermatogenesis. Rosiglitazone (RSG) is a member of the thiazolidinedione family and is a peroxisome proliferator-activated receptor-γ (PPARγ) agonist. It has been reported that RSG protects various types of cells from fatty acid-induced damage. However, whether RSG serves a protective role in Sertoli cells against palmitic acid (PA)-induced toxicity remains to be elucidated. Therefore, the aim of the present study was to investigate the effect of RSG on PA-induced cytotoxicity in Sertoli cells. MTT assay and Oil Red O staining revealed that RSG ameliorated the PA-induced decrease in TM4 cell viability, which was accompanied by an alleviation of PA-induced lipid accumulation in cells. In primary mouse Sertoli cells, RSG also showed similar protective effects against PA-induced lipotoxicity. Knockdown of PPARγ verified that RSG exerted its protective role in TM4 cells through a PPARγ-dependent pathway. To evaluate the mechanism underlying the protective role of RSG on PA-induced lipotoxicity, the present study analyzed the effects of RSG on PA uptake, and the expression of genes associated with both fatty acid oxidation and triglyceride synthesis. The results demonstrated that although RSG did not affect the endocytosis of PA, it significantly elevated the expression of carnitine palmitoyltransferase (CPT)-1A, a key enzyme involved in fatty acid oxidation, which indicated that the protective effect of RSG may have an important role in fatty acid oxidation. On the other hand, the expression of CPT1B was not affected by RSG. Moreover, the expression levels of diacylglycerol O-acyltransferase (DGAT)-1 and DGAT2, both of which encode enzymes catalyzing the synthesis of triglycerides, were not suppressed by RSG. The results indicated that RSG reduced PA-induced lipid accumulation by promoting fatty acid oxidation mediated by CPT1A. The effect of RSG in protecting cells from lipotoxicity was also found to be specific to Sertoli cells and hepatocytes, and not to other cell types that do not store excess lipid in large quantities, such as human umbilical vein endothelial cells. These findings provide insights into the cytoprotective effects of RSG on Sertoli cells and suggest that PPARγ activation may be a useful therapeutic method for the treatment of Sertoli cell dysfunction caused by dyslipidemia.
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Affiliation(s)
- Xie Ge
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Peng Pan
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Jun Jing
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Xuechun Hu
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Li Chen
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Xuhua Qiu
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Rujun Ma
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Kadiliya Jueraitetibaike
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Xuan Huang
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
| | - Bing Yao
- 0000 0001 2314 964Xgrid.41156.37Center of Reproductive Medicine, Nanjing Jinling Hospital, Clinical School of Medical College, Nanjing University, Nanjing, 210002 Jiangsu China
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Vatner DF, Goedeke L, Camporez JPG, Lyu K, Nasiri AR, Zhang D, Bhanot S, Murray SF, Still CD, Gerhard GS, Shulman GI, Samuel VT. Angptl8 antisense oligonucleotide improves adipose lipid metabolism and prevents diet-induced NAFLD and hepatic insulin resistance in rodents. Diabetologia 2018; 61:1435-1446. [PMID: 29497783 PMCID: PMC5940564 DOI: 10.1007/s00125-018-4579-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 01/29/2018] [Indexed: 12/20/2022]
Abstract
AIMS/HYPOTHESIS Targeting regulators of adipose tissue lipoprotein lipase could enhance adipose lipid clearance, prevent ectopic lipid accumulation and consequently ameliorate insulin resistance and type 2 diabetes. Angiopoietin-like 8 (ANGPTL8) is an insulin-regulated lipoprotein lipase inhibitor strongly expressed in murine adipose tissue. However, Angptl8 knockout mice do not have improved insulin resistance. We hypothesised that pharmacological inhibition, using a second-generation antisense oligonucleotide (ASO) against Angptl8 in adult high-fat-fed rodents, would prevent ectopic lipid accumulation and insulin resistance by promoting adipose lipid uptake. METHODS ANGPTL8 expression was assessed by quantitative PCR in omental adipose tissue of bariatric surgery patients. High-fat-fed Sprague Dawley rats and C57BL/6 mice were treated with ASO against Angptl8 and insulin sensitivity was assessed by hyperinsulinaemic-euglycaemic clamps in rats and glucose tolerance tests in mice. Factors mediating lipid-induced hepatic insulin resistance were assessed, including lipid content, protein kinase Cε (PKCε) activation and insulin-stimulated Akt phosphorylation. Rat adipose lipid uptake was assessed by mixed meal tolerance tests. Murine energy balance was assessed by indirect calorimetry. RESULTS Omental fat ANGPTL8 mRNA expression is higher in obese individuals with fatty liver and insulin resistance compared with BMI-matched insulin-sensitive individuals. Angptl8 ASO prevented hepatic steatosis, PKCε activation and hepatic insulin resistance in high-fat-fed rats. Postprandial triacylglycerol uptake in white adipose tissue was increased in Angptl8 ASO-treated rats. Angptl8 ASO protected high-fat-fed mice from glucose intolerance. Although there was no change in net energy balance, Angptl8 ASO increased fat mass in high-fat-fed mice. CONCLUSIONS/INTERPRETATION Disinhibition of adipose tissue lipoprotein lipase is a novel therapeutic modality to enhance adipose lipid uptake and treat non-alcoholic fatty liver disease and insulin resistance. In line with this, adipose ANGPTL8 is a candidate therapeutic target for these conditions.
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Affiliation(s)
- Daniel F Vatner
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA.
| | - Leigh Goedeke
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA
| | - Joao-Paulo G Camporez
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA
| | - Kun Lyu
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Ali R Nasiri
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA
| | - Dongyan Zhang
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, 06520, USA
| | | | | | | | - Glenn S Gerhard
- Obesity Institute, Geisinger Health System, Danville, PA, 17822, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT, 06520, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, 06520, USA
| | - Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, P.O. Box 208020, New Haven, CT, 06520, USA.
- Veterans Affairs Medical Center, 950 Campbell Ave, BLG 5 3rd floor, West Haven, CT, 06516, USA.
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10
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Bakshi I, Suryana E, Small L, Quek LE, Brandon AE, Turner N, Cooney GJ. Fructose bisphosphatase 2 overexpression increases glucose uptake in skeletal muscle. J Endocrinol 2018; 237:101-111. [PMID: 29507044 DOI: 10.1530/joe-17-0555] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 03/05/2018] [Indexed: 12/31/2022]
Abstract
Skeletal muscle is a major tissue for glucose metabolism and can store glucose as glycogen, convert glucose to lactate via glycolysis and fully oxidise glucose to CO2 Muscle has a limited capacity for gluconeogenesis but can convert lactate and alanine to glycogen. Gluconeogenesis requires FBP2, a muscle-specific form of fructose bisphosphatase that converts fructose-1,6-bisphosphate (F-1,6-bisP) to fructose-6-phosphate (F-6-P) opposing the activity of the ATP-consuming enzyme phosphofructokinase (PFK). In mammalian muscle, the activity of PFK is normally 100 times higher than FBP2 and therefore energy wasting cycling between PFK and FBP2 is low. In an attempt to increase substrate cycling between F-6-P and F-1,6-bisP and alter glucose metabolism, we overexpressed FBP2 using a muscle-specific adeno-associated virus (AAV-tMCK-FBP2). AAV was injected into the right tibialis muscle of rats, while the control contralateral left tibialis received a saline injection. Rats were fed a chow or 45% fat diet (HFD) for 5 weeks after which, hyperinsulinaemic-euglycaemic clamps were performed. Infection of the right tibialis with AAV-tMCK-FBP2 increased FBP2 activity 10 fold on average in chow and HFD rats (P < 0.0001). Overexpression of FBP2 significantly increased insulin-stimulated glucose uptake in tibialis of chow animals (control 14.3 ± 1.7; FBP2 17.6 ± 1.6 µmol/min/100 g) and HFD animals (control 9.6 ± 1.1; FBP2 11.2 ± 1.1µmol/min/100 g). The results suggest that increasing the capacity for cycling between F-1,6-bisP and F-6-P can increase the metabolism of glucose by introducing a futile cycle in muscle, but this increase is not sufficient to overcome muscle insulin resistance.
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Affiliation(s)
- Ishita Bakshi
- Diabetes and Metabolism DivisionGarvan Institute, Sydney, New South Wales, Australia
| | - Eurwin Suryana
- Diabetes and Metabolism DivisionGarvan Institute, Sydney, New South Wales, Australia
| | - Lewin Small
- Diabetes and Metabolism DivisionGarvan Institute, Sydney, New South Wales, Australia
| | - Lake-Ee Quek
- School of Mathematics and StatisticsUniversity of Sydney, Charles Perkins Centre, Sydney, New South Wales, Australia
| | - Amanda E Brandon
- Diabetes and Metabolism DivisionGarvan Institute, Sydney, New South Wales, Australia
- Sydney Medical SchoolCharles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
| | - Nigel Turner
- Department of PharmacologySchool of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Gregory J Cooney
- Diabetes and Metabolism DivisionGarvan Institute, Sydney, New South Wales, Australia
- Sydney Medical SchoolCharles Perkins Centre, University of Sydney, Sydney, New South Wales, Australia
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11
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Han JH, Tuan NQ, Park MH, Quan KT, Oh J, Heo KS, Na M, Myung CS. Cucurbitane Triterpenoids from the Fruits of Momordica Charantia
Improve Insulin Sensitivity and Glucose Homeostasis in Streptozotocin-Induced Diabetic Mice. Mol Nutr Food Res 2018; 62:e1700769. [DOI: 10.1002/mnfr.201700769] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 12/31/2017] [Indexed: 12/16/2022]
Affiliation(s)
- Joo-Hui Han
- Department of Pharmacology; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - Nguyen Quoc Tuan
- Department of Pharmacognosy; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - Min-Ho Park
- Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - Khong Trong Quan
- Department of Pharmacognosy; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - Joonseok Oh
- Department of Chemistry; Yale University; New Haven CT USA
| | - Kyung-Sun Heo
- Department of Pharmacology; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - MinKyun Na
- Department of Pharmacognosy; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
| | - Chang-Seon Myung
- Department of Pharmacology; Chungnam National University College of Pharmacy; Daejeon Republic of Korea
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12
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Kim K, Boo K, Yu YS, Oh SK, Kim H, Jeon Y, Bhin J, Hwang D, Kim KI, Lee JS, Im SS, Yoon SG, Kim IY, Seong JK, Lee H, Fang S, Baek SH. RORα controls hepatic lipid homeostasis via negative regulation of PPARγ transcriptional network. Nat Commun 2017; 8:162. [PMID: 28757615 PMCID: PMC5534431 DOI: 10.1038/s41467-017-00215-1] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 06/09/2017] [Indexed: 01/15/2023] Open
Abstract
The retinoic acid receptor-related orphan receptor-α (RORα) is an important regulator of various biological processes, including cerebellum development, circadian rhythm and cancer. Here, we show that hepatic RORα controls lipid homeostasis by negatively regulating transcriptional activity of peroxisome proliferators-activated receptor-γ (PPARγ) that mediates hepatic lipid metabolism. Liver-specific Rorα-deficient mice develop hepatic steatosis, obesity and insulin resistance when challenged with a high-fat diet (HFD). Global transcriptome analysis reveals that liver-specific deletion of Rorα leads to the dysregulation of PPARγ signaling and increases hepatic glucose and lipid metabolism. RORα specifically binds and recruits histone deacetylase 3 (HDAC3) to PPARγ target promoters for the transcriptional repression of PPARγ. PPARγ antagonism restores metabolic homeostasis in HFD-fed liver-specific Rorα deficient mice. Our data indicate that RORα has a pivotal role in the regulation of hepatic lipid homeostasis. Therapeutic strategies designed to modulate RORα activity may be beneficial for the treatment of metabolic disorders.Hepatic steatosis development may result from dysregulation of lipid metabolism, which is finely tuned by several transcription factors including the PPAR family. Here Kim et al. show that the nuclear receptor RORα inhibits PPARγ-mediated transcriptional activity by interacting with HDAC3 and competing for the promoters of lipogenic genes.
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Affiliation(s)
- Kyeongkyu Kim
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea
| | - Kyungjin Boo
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea
| | - Young Suk Yu
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea
| | - Se Kyu Oh
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea
| | - Hyunkyung Kim
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea
| | - Yoon Jeon
- Graduate School of Cancer Science and Policy, Research Institute, National Cancer Center, Gyeonggi-do, 10408, South Korea
| | - Jinhyuk Bhin
- Department of New Biology and Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu, 42988, South Korea
| | - Daehee Hwang
- Department of New Biology and Center for Plant Aging Research, Institute for Basic Science, DGIST, Daegu, 42988, South Korea
| | - Keun Il Kim
- Department of Biological Sciences, Sookmyung Women's University, Seoul, 04310, South Korea
| | - Jun-Su Lee
- Department of Physiology, Keimyung University School of Medicine, Daegu, 42601, South Korea
| | - Seung-Soon Im
- Department of Physiology, Keimyung University School of Medicine, Daegu, 42601, South Korea
| | - Seul Gi Yoon
- Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
- Korea Mouse Phenotyping Center, Seoul, 08826, South Korea
| | - Il Yong Kim
- Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
- Korea Mouse Phenotyping Center, Seoul, 08826, South Korea
| | - Je Kyung Seong
- Laboratory of Developmental Biology and Genomics, College of Veterinary Medicine, Research Institute for Veterinary Science, Seoul National University, Seoul, 08826, South Korea
- Korea Mouse Phenotyping Center, Seoul, 08826, South Korea
- BK21 Plus Program for Creative Veterinary Science Research, BIO-MAX institute, Interdisciplinary Program for Bioinformatics and Program for Cancer Biology, Seoul National University, Seoul, 08826, South Korea
| | - Ho Lee
- Graduate School of Cancer Science and Policy, Research Institute, National Cancer Center, Gyeonggi-do, 10408, South Korea
| | - Sungsoon Fang
- Severance Biomedical Science Institute, BK21 Plus Project for Medical Science, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, 06273, South Korea.
| | - Sung Hee Baek
- Department of Biological Sciences, Creative Research Initiatives Center for Chromatin Dynamics, Seoul National University, Seoul, 08826, South Korea.
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13
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Lu C, Cardoso RC, Puttabyatappa M, Padmanabhan V. Developmental Programming: Prenatal Testosterone Excess and Insulin Signaling Disruptions in Female Sheep. Biol Reprod 2016; 94:113. [PMID: 27053365 PMCID: PMC4939741 DOI: 10.1095/biolreprod.115.136283] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/05/2016] [Indexed: 12/25/2022] Open
Abstract
Women with polycystic ovary syndrome often manifest insulin resistance. Using a sheep model of polycystic ovary syndrome-like phenotype, we explored the contribution of androgen and insulin in programming and maintaining disruptions in insulin signaling in metabolic tissues. Phosphorylation of AKT, ERK, GSK3beta, mTOR, and p70S6K was examined in the liver, muscle, and adipose tissue of control and prenatal testosterone (T)-, prenatal T plus androgen antagonist (flutamide)-, and prenatal T plus insulin sensitizer (rosiglitazone)-treated fetuses as well as 2-yr-old females. Insulin-stimulated phospho (p)-AKT was evaluated in control and prenatal T-, prenatal T plus postnatal flutamide-, and prenatal T plus postnatal rosiglitazone-treated females at 3 yr of age. GLUT4 expression was evaluated in the muscle at all time points. Prenatal T treatment increased mTOR, p-p70S6K, and p-GSK3beta levels in the fetal liver with both androgen antagonist and insulin sensitizer preventing the mTOR increase. Both interventions had partial effect in preventing the increase in p-GSK3beta. In the fetal muscle, prenatal T excess decreased p-GSK3beta and GLUT4. The decrease in muscle p-GSK3beta was partially prevented by insulin sensitizer cotreatment. Both interventions partially prevented the decrease in GLUT4. Prenatal T treatment had no effect on basal expression of any of the markers in 2-yr-old females. At 3 yr of age, prenatal T treatment prevented the insulin-stimulated increase in p-AKT in liver and muscle, but not in adipose tissue, and neither postnatal intervention restored p-AKT response to insulin stimulation. Our findings provide evidence that prenatal T excess changes insulin sensitivity in a tissue- and development-specific manner and that both androgens and insulin may be involved in the programming of these metabolic disruptions.
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Affiliation(s)
- Chunxia Lu
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
| | - Rodolfo C Cardoso
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan
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14
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Choi SS, Park J, Choi JH. Revisiting PPARγ as a target for the treatment of metabolic disorders. BMB Rep 2015; 47:599-608. [PMID: 25154720 PMCID: PMC4281338 DOI: 10.5483/bmbrep.2014.47.11.174] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Indexed: 02/03/2023] Open
Abstract
As the prevalence of obesity has increased explosively over the last several decades, associated metabolic disorders, including type 2 diabetes, dyslipidemia, hypertension, and cardiovascular diseases, have been also increased. Thus, new strategies for preventing and treating them are needed. The nuclear peroxisome proliferator-activated receptors (PPARs) are involved fundamentally in regulating energy homeostasis; thus, they have been considered attractive drug targets for addressing metabolic disorders. Among the PPARs, PPARγ is a master regulator of gene expression for metabolism, inflammation, and other pathways in many cell types, especially adipocytes. It is a physiological receptor of the
potent anti-diabetic drugs of the thiazolidinediones (TZDs) class, including rosiglitazone (Avandia). However, TZDs have undesirable and severe side effects, such as weight gain, fluid
retention, and cardiovascular dysfunction. Recently, many reports have suggested that PPARγ could be modulated by post-translational modifications (PTMs), and modulation of
PTM has been considered as novel approaches for treating metabolic disorders with fewer side effects than the TZDs. In this review, we discuss how PTM of PPARγ may be regulated and issues to be considered in making novel anti-diabetic drugs that can modulate the PTM of PPARγ. [BMB Reports 2014; 47(11): 599-608]
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Affiliation(s)
- Sun-Sil Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jiyoung Park
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
| | - Jang Hyun Choi
- Department of Biological Science, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798, Korea
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15
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Jia C, Huan Y, Liu S, Hou S, Sun S, Li C, Liu Q, Jiang Q, Wang Y, Shen Z. Effect of Chronic Pioglitazone Treatment on Hepatic Gene Expression Profile in Obese C57BL/6J Mice. Int J Mol Sci 2015; 16:12213-29. [PMID: 26035752 PMCID: PMC4490440 DOI: 10.3390/ijms160612213] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 01/07/2023] Open
Abstract
Pioglitazone, a selective ligand of peroxisome proliferator-activated receptor gamma (PPARγ), is an insulin sensitizer drug that is being used in a number of insulin-resistant conditions, including non-alcoholic fatty liver disease (NAFLD). However, there is a discrepancy between preclinical and clinical data in the literature and the benefits of pioglitazone treatment as well as the precise mechanism of action remain unclear. In the present study, we determined the effect of chronic pioglitazone treatment on hepatic gene expression profile in diet-induced obesity (DIO) C57BL/6J mice in order to understand the mechanisms of NAFLD induced by PPARγ agonists. DIO mice were treated with pioglitazone (25 mg/kg/day) for 38 days, the gene expression profile in liver was evaluated using Affymetrix Mouse GeneChip 1.0 ST array. Pioglitazone treatment resulted in exacerbated hepatic steatosis and increased hepatic triglyceride and free fatty acids concentrations, though significantly increased the glucose infusion rate in hyperinsulinemic-euglycemic clamp test. The differentially expressed genes in liver of pioglitazone treated vs. untreated mice include 260 upregulated and 86 downregulated genes. Gene Ontology based enrichment analysis suggests that inflammation response is transcriptionally downregulated, while lipid metabolism is transcriptionally upregulated. This may underlie the observed aggravating liver steatosis and ameliorated systemic insulin resistance in DIO mice.
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Affiliation(s)
- Chunming Jia
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Yi Huan
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Shuainan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Shaocong Hou
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Sujuan Sun
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Caina Li
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Quan Liu
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Qian Jiang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Yue Wang
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
| | - Zhufang Shen
- State Key Laboratory of Bioactive Substances and Functions of Natural Medicines, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100050, China.
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16
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Rosiglitazone inhibits hepatic insulin resistance induced by chronic pancreatitis and IKK-β/NF-κB expression in liver. Pancreas 2014; 43:1291-8. [PMID: 25036911 DOI: 10.1097/mpa.0000000000000173] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES This study aimed to investigate the influence of rosiglitazone on hepatic insulin resistance and the expressions of IκB kinase-β (IKK-β)/nuclear factor-κB (NF-κB) in chronic pancreatitis (CP). METHODS After CP was induced in rats, rosiglitazone and GW9662 were administered at the doses of 4 and 2 mg/kg per day for 4 weeks, respectively. Then, glucose and insulin tolerance tests were performed. Hepatocytes were isolated for the glucose release experiments. Determination of the IKK-β, NF-κB, and Ser307p-insulin receptor substrates-1 (Ser307p-IRS-1) expression in the liver was performed. RESULTS The increased plasma glucose, reduced insulin sensitivity, and the capacity of insulin to suppress glucose release in hepatocytes were observed in CP rats. The IKK-β, NF-κB, and Ser307p-IRS-1 expressions were significantly higher in the liver of CP rats than in sham-operated rats (P < 0.05). Rosiglitazone treatment significantly improved hepatic insulin sensitivity and inhibited the IKK-β, NF-κB, and Ser307p-IRS-1 expressions in the liver (P < 0.05). Counteraction with peroxisome proliferator-activated receptor-γ by GW9662 attenuated the aforementioned effects of rosiglitazone. CONCLUSIONS Rosiglitazone attenuates hepatic insulin resistance induced by CP. The inhibition of hepatic IKK-β and NF-κB expressions via peroxisome proliferator-activated receptor-γ may be involved in the therapeutic effect of rosiglitazone.
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Abstract
Type 2 diabetes is caused by insulin resistance coupled with an inability to produce enough insulin to control blood glucose, and thiazolidinediones (TZDs) are the only current antidiabetic agents that function primarily by increasing insulin sensitivity. However, despite clear benefits in glycemic control, this class of drugs has recently fallen into disuse due to concerns over side effects and adverse events. Here we review the clinical data and attempt to balance the benefits and risks of TZD therapy. We also examine potential mechanisms of action for the beneficial and harmful effects of TZDs, mainly via agonism of the nuclear receptor PPARγ. Based on critical appraisal of both preclinical and clinical studies, we discuss the prospect of harnessing the insulin sensitizing effects of PPARγ for more effective, safe, and potentially personalized treatments of type 2 diabetes.
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Affiliation(s)
- Raymond E Soccio
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric R Chen
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mitchell A Lazar
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Department of Genetics, and The Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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18
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The role of hepatic lipids in hepatic insulin resistance and type 2 diabetes. Nature 2014; 510:84-91. [PMID: 24899308 DOI: 10.1038/nature13478] [Citation(s) in RCA: 850] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 03/14/2014] [Indexed: 02/07/2023]
Abstract
Non-alcoholic fatty liver disease and its downstream sequelae, hepatic insulin resistance and type 2 diabetes, are rapidly growing epidemics, which lead to increased morbidity and mortality rates, and soaring health-care costs. Developing interventions requires a comprehensive understanding of the mechanisms by which excess hepatic lipid develops and causes hepatic insulin resistance and type 2 diabetes. Proposed mechanisms implicate various lipid species, inflammatory signalling and other cellular modifications. Studies in mice and humans have elucidated a key role for hepatic diacylglycerol activation of protein kinase Cε in triggering hepatic insulin resistance. Therapeutic approaches based on this mechanism could alleviate the related epidemics of non-alcoholic fatty liver disease and type 2 diabetes.
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Zachariah Tom R, Garcia-Roves PM, Sjögren RJO, Jiang LQ, Holmström MH, Deshmukh AS, Vieira E, Chibalin AV, Björnholm M, Zierath JR. Effects of AMPK activation on insulin sensitivity and metabolism in leptin-deficient ob/ob mice. Diabetes 2014; 63:1560-71. [PMID: 24487023 DOI: 10.2337/db13-0670] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AMP-activated protein kinase (AMPK) is a heterotrimeric complex, composed of a catalytic subunit (α) and two regulatory subunits (β and γ), which act as a metabolic sensor to regulate glucose and lipid metabolism. A mutation in the γ3 subunit (AMPKγ3(R225Q)) increases basal AMPK phosphorylation, while concomitantly reducing sensitivity to AMP. AMPKγ3(R225Q) (γ3(R225Q)) transgenic mice are protected against dietary-induced triglyceride accumulation and insulin resistance. We determined whether skeletal muscle-specific expression of AMPKγ3(R225Q) prevents metabolic abnormalities in leptin-deficient ob/ob (ob/ob-γ3(R225Q)) mice. Glycogen content was increased, triglyceride content was decreased, and diacylglycerol and ceramide content were unaltered in gastrocnemius muscle from ob/ob-γ3(R225Q) mice, whereas glucose tolerance was unaltered. Insulin-stimulated glucose uptake in extensor digitorum longus muscle during the euglycemic-hyperinsulinemic clamp was increased in lean γ3(R225Q) mice, but not in ob/ob-γ3(R225Q) mice. Acetyl-CoA carboxylase phosphorylation was increased in gastrocnemius muscle from γ3(R225Q) mutant mice independent of adiposity. Glycogen and triglyceride content were decreased after leptin treatment (5 days) in ob/ob mice, but not in ob/ob-γ3(R225Q) mice. In conclusion, metabolic improvements arising from muscle-specific expression of AMPKγ3(R225Q) are insufficient to ameliorate insulin resistance and obesity in leptin-deficient mice. Central defects due to leptin deficiency may override any metabolic benefit conferred by peripheral overexpression of the AMPKγ3(R225Q) mutation.
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Affiliation(s)
- Robby Zachariah Tom
- Integrative Physiology, Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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Hemmeryckx B, Gaekens M, Gallacher DJ, Lu HR, Lijnen HR. Effect of rosiglitazone on liver structure and function in genetically diabetic Akita mice. Basic Clin Pharmacol Toxicol 2013; 113:353-60. [PMID: 23789962 DOI: 10.1111/bcpt.12104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 06/17/2013] [Indexed: 12/14/2022]
Abstract
Genetically diabetic Akita mice, kept on a high-fat and high-cholesterol diet, and treated with the peroxisome proliferator-activated receptor-γ agonist rosiglitazone (10 mg/kg per day during 4 months), displayed rosiglitazone-induced side effects, similar to those observed in patients, including weight and fat gain and early signs of hypertrophic cardiomyopathy. As several cases of hepatotoxicity were reported in patients receiving rosiglitazone treatment, this study evaluated whether rosiglitazone also induced hepatotoxicity in these diabetic animals. Liver structure and function was analysed in wild-type and rosiglitazone-treated and untreated Akita mice, kept for 4 months on the high-fat and high-cholesterol diet. Decreased circulating levels of the liver enzymes aspartate and alanine aminotransferase and increased levels of alkaline phosphatases were observed upon rosiglitazone treatment, whereas liver weight was markedly increased. Rosiglitazone administration was associated with liver steatosis, as demonstrated by triglyceride accumulation. However, gene expression of steatosis markers in liver tissue was not markedly affected by rosiglitazone treatment, while expression of fatty acid transport protein was reduced by rosiglitazone treatment, suggesting an impairment of the fatty acid β-oxidation pathway. mRNA expression of pro- and anti-oxidant enzymes and liver 3-nitrotyrosine content was not affected. Furthermore, gene and protein expression of macrophage markers and of cell adhesion molecules did not indicate progression to steatohepatitis, whereas an unaltered collagen deposition did not suggest steatofibrosis. In conclusion, rosiglitazone treatment of diabetic Akita mice induced liver steatosis without, however, progression to more advanced stages of liver disease.
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Affiliation(s)
- Bianca Hemmeryckx
- Center for Molecular and Vascular Biology, Department of Cardiovascular Sciences, KU Leuven, Leuven, Belgium
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21
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Ahmadian M, Suh JM, Hah N, Liddle C, Atkins AR, Downes M, Evans RM. PPARγ signaling and metabolism: the good, the bad and the future. Nat Med 2013; 19:557-66. [PMID: 23652116 PMCID: PMC3870016 DOI: 10.1038/nm.3159] [Citation(s) in RCA: 1660] [Impact Index Per Article: 138.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 03/06/2013] [Indexed: 11/09/2022]
Abstract
Thiazolidinediones (TZDs) are potent insulin sensitizers that act through the nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) and are highly effective oral medications for type 2 diabetes. However, their unique benefits are shadowed by the risk for fluid retention, weight gain, bone loss and congestive heart failure. This raises the question as to whether it is possible to build a safer generation of PPARγ-specific drugs that evoke fewer side effects while preserving insulin-sensitizing potential. Recent studies that have supported the continuing physiologic and therapeutic relevance of the PPARγ pathway also provide opportunities to develop newer classes of molecules that reduce or eliminate adverse effects. This review highlights key advances in understanding PPARγ signaling in energy homeostasis and metabolic disease and also provides new explanations for adverse events linked to TZD-based therapy.
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Affiliation(s)
- Maryam Ahmadian
- Gene Expression Laboratory, Salk Institute for Biological Studies, La Jolla, California, USA
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22
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Does rosiglitazone affect adiposity and cardiac function in genetic diabetic mice? Eur J Pharmacol 2013; 700:23-31. [DOI: 10.1016/j.ejphar.2012.11.062] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Revised: 11/09/2012] [Accepted: 11/19/2012] [Indexed: 12/24/2022]
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Idealized PPARγ-Based Therapies: Lessons from Bench and Bedside. PPAR Res 2012; 2012:978687. [PMID: 22745632 PMCID: PMC3382399 DOI: 10.1155/2012/978687] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 04/23/2012] [Indexed: 01/07/2023] Open
Abstract
The incidence of type 2 (T2D) diabetes and other chronic conditions associated with insulin resistance is increasing at an alarming rate, underscoring the need for effective and safe therapeutic strategies. Peroxisome-proliferator-activated receptor gamma (PPARγ) has emerged as a critical regulator of glucose homeostasis, lipid homeostasis, and vascular inflammation. Currently marketed drugs targeting this receptor, the thiazolidinediones (TZDs), have proven benefits on insulin resistance and hyperglycemia associated with T2D. Unfortunately, they have been associated with long-term unfavorable effects on health, such as weight gain, plasma volume expansion, bone loss, cardiovascular toxicity, and possibly cancer, and these safety concerns have led to reduced interest for many PPARγ ligands. However, over the last years, data from human genetic studies, animal models, and studies with ligands have increased our understanding of PPARγ's actions and provided important insights into how ligand development strategies could be optimized to increase effectiveness and safety of PPARγ-based therapies.
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Abstract
Nonalcoholic fatty liver disease (NAFLD) is now the most frequent chronic liver disease in Western societies, affecting one in four adults in the USA, and is strongly associated with hepatic insulin resistance, a major risk factor in the pathogenesis of type 2 diabetes. Although the cellular mechanisms underlying this relationship are unknown, hepatic accumulation of diacylglycerol (DAG) in both animals and humans has been linked to hepatic insulin resistance. In this Perspective, we discuss the role of DAG activation of protein kinase Cε as the mechanism responsible for NAFLD-associated hepatic insulin resistance seen in obesity, type 2 diabetes, and lipodystrophy.
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Affiliation(s)
- François R Jornayvaz
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06510, USA
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25
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Ayala JE, Bracy DP, Malabanan C, James FD, Ansari T, Fueger PT, McGuinness OP, Wasserman DH. Hyperinsulinemic-euglycemic clamps in conscious, unrestrained mice. J Vis Exp 2011:3188. [PMID: 22126863 PMCID: PMC3308587 DOI: 10.3791/3188] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Type 2 diabetes is characterized by a defect in insulin action. The hyperinsulinemic-euglycemic clamp, or insulin clamp, is widely considered the "gold standard" method for assessing insulin action in vivo. During an insulin clamp, hyperinsulinemia is achieved by a constant insulin infusion. Euglycemia is maintained via a concomitant glucose infusion at a variable rate. This variable glucose infusion rate (GIR) is determined by measuring blood glucose at brief intervals throughout the experiment and adjusting the GIR accordingly. The GIR is indicative of whole-body insulin action, as mice with enhanced insulin action require a greater GIR. The insulin clamp can incorporate administration of isotopic 2[14C]deoxyglucose to assess tissue-specific glucose uptake and [3-3H]glucose to assess the ability of insulin to suppress the rate of endogenous glucose appearance (endoRa), a marker of hepatic glucose production, and to stimulate the rate of whole-body glucose disappearance (Rd). The miniaturization of the insulin clamp for use in genetic mouse models of metabolic disease has led to significant advances in diabetes research. Methods for performing insulin clamps vary between laboratories. It is important to note that the manner in which an insulin clamp is performed can significantly affect the results obtained. We have published a comprehensive assessment of different approaches to performing insulin clamps in conscious mice1 as well as an evaluation of the metabolic response of four commonly used inbred mouse strains using various clamp techniques2. Here we present a protocol for performing insulin clamps on conscious, unrestrained mice developed by the Vanderbilt Mouse Metabolic Phenotyping Center (MMPC; URL: www.mc.vanderbilt.edu/mmpc). This includes a description of the method for implanting catheters used during the insulin clamp. The protocol employed by the Vanderbilt MMPC utilizes a unique two-catheter system3. One catheter is inserted into the jugular vein for infusions. A second catheter is inserted into the carotid artery, which allows for blood sampling without the need to restrain or handle the mouse. This technique provides a significant advantage to the most common method for obtaining blood samples during insulin clamps which is to sample from the severed tip of the tail. Unlike this latter method, sampling from an arterial catheter is not stressful to the mouse1. We also describe methods for using isotopic tracer infusions to assess tissue-specific insulin action. We also provide guidelines for the appropriate presentation of results obtained from insulin clamps.
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Affiliation(s)
- Julio E Ayala
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute at Lake Nona, USA.
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Mynarcik DC, McNurlan MA, Melendez MM, Vosswinkel JA, Gelato MC. Rosiglitazone-Mediated Effects on Skeletal Muscle Gene Expression Correlate with Improvements in Insulin Sensitivity in Individuals with HIV-Insulin Resistance. PATHOLOGY RESEARCH INTERNATIONAL 2011; 2011:736425. [PMID: 21559208 PMCID: PMC3090220 DOI: 10.4061/2011/736425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Accepted: 02/21/2011] [Indexed: 11/20/2022]
Abstract
Rosiglitazone, an agonist of peroxisome proliferator activated receptor (PPARγ), improves insulin sensitivity by increasing insulin-stimulated glucose uptake into muscle tissue. This study was undertaken to assess changes in expression of PPAR-regulated genes in muscle tissue following treatment of HIV-associated insulin resistance with rosiglitazone. Muscle gene expression was assessed in twenty-two seronegative HIV subjects (control), 21 HIV-infected individuals with normal insulin sensitivity (HIV-IS) and 19 HIV-infected individuals with insulin resistance (HIV-IR). A subset of the HIV-IR group (N=10) were re-evaluated 12 weeks after treatment with 8 mg/d of rosiglitazone. The HIV-IR group's rosiglitazone-mediated improvement in insulin sensitivity was highly correlated with increased expression of PPARγ and carnitine palmitoyl transferase-1 (CPT-1), (r=0.87, P<.001) and (r=0.95, P<.001), respectively. The changes in PPARγ expression were also correlated with the changes in CPT1 expression (r=0.75, P=.009). The results suggest that rosiglitazone; may have a direct effect on muscle tissue to improve insulin sensitivity.
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Affiliation(s)
- Dennis C. Mynarcik
- Division of Endocrinology, Department of Medicine, Stony Brook University Medical Center, HSC T15-060, Stony Brook, NY 11794-8154, USA
| | - Margaret A. McNurlan
- Department of Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794-8154, USA
| | - Mark M. Melendez
- Department of Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794-8154, USA
| | - James A. Vosswinkel
- Department of Surgery, Stony Brook University Medical Center, Stony Brook, NY 11794-8154, USA
| | - Marie C. Gelato
- Division of Endocrinology, Department of Medicine, Stony Brook University Medical Center, HSC T15-060, Stony Brook, NY 11794-8154, USA
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Qi Y, Longo KA, Giuliana DJ, Gagne S, McDonagh T, Govek E, Nolan A, Zou C, Morgan K, Hixon J, Saunders JO, Distefano PS, Geddes BJ. Characterization of the insulin sensitivity of ghrelin receptor KO mice using glycemic clamps. BMC PHYSIOLOGY 2011; 11:1. [PMID: 21211044 PMCID: PMC3024223 DOI: 10.1186/1472-6793-11-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2010] [Accepted: 01/06/2011] [Indexed: 12/14/2022]
Abstract
Background We and others have demonstrated previously that ghrelin receptor (GhrR) knock out (KO) mice fed a high fat diet (HFD) have increased insulin sensitivity and metabolic flexibility relative to WT littermates. A striking feature of the HFD-fed GhrR KO mouse is the dramatic decrease in hepatic steatosis. To characterize further the underlying mechanisms of glucose homeostasis in GhrR KO mice, we conducted both hyperglycemic (HG) and hyperinsulinemic-euglycemic (HI-E) clamps. Additionally, we investigated tissue glucose uptake and specifically examined liver insulin sensitivity. Results Consistent with glucose tolerance-test data, in HG clamp experiments, GhrR KO mice showed a reduction in glucose-stimulated insulin release relative to WT littermates. Nevertheless, a robust 1st phase insulin secretion was still achieved, indicating that a healthy β-cell response is maintained. Additionally, GhrR KO mice demonstrated both a significantly increased glucose infusion rate and significantly reduced insulin requirement for maintenance of the HG clamp, consistent with their relative insulin sensitivity. In HI-E clamps, both LFD-fed and HFD-fed GhrR KO mice showed higher peripheral insulin sensitivity relative to WT littermates as indicated by a significant increase in insulin-stimulated glucose disposal (Rd), and decreased hepatic glucose production (HGP). HFD-fed GhrR KO mice showed a marked increase in peripheral tissue glucose uptake in a variety of tissues, including skeletal muscle, brown adipose tissue and white adipose tissue. GhrR KO mice fed a HFD also showed a modest, but significant decrease in conversion of pyruvate to glucose, as would be anticipated if these mice displayed increased liver insulin sensitivity. Additionally, the levels of UCP2 and UCP1 were reduced in the liver and BAT, respectively, in GhrR KO mice relative to WT mice. Conclusions These results indicate that improved glucose homeostasis of GhrR KO mice is characterized by robust improvements of glucose disposal in both normal and metabolically challenged states, relative to WT controls. GhrR KO mice have an intact 1st phase insulin response but require significantly less insulin for glucose disposal. Our experiments reveal that the insulin sensitivity of GhrR KO mice is due to both BW independent and dependent factors. We also provide several lines of evidence that a key feature of the GhrR KO mouse is maintenance of hepatic insulin sensitivity during metabolic challenge.
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Affiliation(s)
- Yong Qi
- Elixir Pharmaceuticals, Inc., 12 Emily St., Cambridge, MA 02139, USA
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Ayala JE, Samuel VT, Morton GJ, Obici S, Croniger CM, Shulman GI, Wasserman DH, McGuinness OP. Standard operating procedures for describing and performing metabolic tests of glucose homeostasis in mice. Dis Model Mech 2010; 3:525-34. [PMID: 20713647 DOI: 10.1242/dmm.006239] [Citation(s) in RCA: 563] [Impact Index Per Article: 37.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Mouse Metabolic Phenotyping Center (MMPC) Consortium was established to address the need to characterize the growing number of mouse models of metabolic diseases, particularly diabetes and obesity. A goal of the MMPC Consortium is to propose standard methods for assessing metabolic phenotypes in mice. In this article, we discuss issues pertaining to the design and performance of various tests of glucose metabolism. We also propose guidelines for the description of methods, presentation of data and interpretation of results. The recommendations presented in this article are based on the experience of the MMPC Consortium and other investigators.
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Affiliation(s)
- Julio E Ayala
- Vanderbilt-NIH Mouse Metabolic Phenotyping Center, Nashville, TN 37232, USA.
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Duan SZ, Usher MG, Foley EL, Milstone DS, Brosius FC, Mortensen RM. Sex dimorphic actions of rosiglitazone in generalised peroxisome proliferator-activated receptor-gamma (PPAR-gamma)-deficient mice. Diabetologia 2010; 53:1493-505. [PMID: 20401461 PMCID: PMC2896206 DOI: 10.1007/s00125-010-1748-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2009] [Accepted: 03/11/2010] [Indexed: 01/19/2023]
Abstract
AIMS/HYPOTHESIS The aim of this study was to determine the dependency on peroxisome proliferator-activated receptor-gamma (PPAR-gamma) of insulin sensitisation and glucose homeostasis by thiazolidinediones using a global Ppar-gamma (also known as Pparg)-knockout mouse model. METHODS Global Mox2-Cre-Ppar-gamma-knockout (MORE-PGKO) mice were treated with rosiglitazone and analysed for insulin sensitivity and glucose metabolism. Metabolic and hormonal variables were determined. Adipose and other tissues were measured and analysed for gene expression. RESULTS Rosiglitazone induced regrowth of fat in female but not male MORE-PGKO mice, and only in specific depots. Insulin sensitivity increased but, surprisingly, was not associated with the typical changes in adipokines, plasma NEFA or tissue triacylglycerol. However, increases in alternatively activated macrophage markers, which have been previously associated with metabolic improvement, were observed in the regrown fat. Rosiglitazone improved glucose homeostasis but not insulin sensitivity in male MORE-PGKO mice, with further increase of insulin associated with an apparent expansion of pancreatic islets. CONCLUSIONS/INTERPRETATION Stimulating fat growth by rosiglitazone is sufficient to improve insulin sensitivity in female mice with 95% PPAR-gamma deficiency. This increase in insulin sensitivity is not likely to be due to changes typically seen in adipokines or lipids but may involve changes in macrophage polarisation that occur independent of PPAR-gamma. In contrast, rosiglitazone improves glucose homeostasis in male mice with similar PPAR-gamma deficiency by increasing insulin production independent of changes in adiposity. Further, the insulin-sensitising effect of rosiglitazone is dependent on PPAR-gamma in this male lipodystrophic model.
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Affiliation(s)
- S. Z. Duan
- Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, MI, USA
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - M. G. Usher
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 7641 Med. Sci. II, 1150 W. Med. Ctr. Dr., Ann Arbor, Michigan 48109-5622, Ann Arbor, MI, USA
| | - E. L. Foley
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 7641 Med. Sci. II, 1150 W. Med. Ctr. Dr., Ann Arbor, Michigan 48109-5622, Ann Arbor, MI, USA
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA
| | - D. S. Milstone
- Vascular Research Division, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - F. C. Brosius
- Department of Internal Medicine, Nephrology Division, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 7641 Med. Sci. II, 1150 W. Med. Ctr. Dr., Ann Arbor, Michigan 48109-5622, Ann Arbor, MI, USA
| | - R. M. Mortensen
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, 7641 Med. Sci. II, 1150 W. Med. Ctr. Dr., Ann Arbor, Michigan 48109-5622, Ann Arbor, MI, USA
- Department of Internal Medicine, Metabolism Endocrinology and Diabetes Division, University of Michigan Medical School, Ann Arbor, MI, USA
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, USA
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Abstract
Understanding the molecular mechanisms of insulin resistance remains a major medical challenge of the twenty-first century. Over the last half-century, many hypotheses have been proposed to explain insulin resistance, and, most recently, inflammation associated with alterations in adipocytokines has become the prevailing hypothesis. Here we discuss diacylglycerol-mediated insulin resistance as an alternative and unifying hypothesis to explain the most common forms of insulin resistance associated with obesity and type 2 diabetes mellitus, as well as lipodystrophy and aging.
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Shao H, Li D, Yang Y, Guo HF, Liu ZY, Si SY, Yang Z, Li ZR. The effect of substituted thiophene and benzothiophene derivates on PPARγ expression and glucose metabolism. J Enzyme Inhib Med Chem 2010. [DOI: 10.3109/14756360903179369] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Huayi Shao
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Dong Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Yi Yang
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Hui-Fang Guo
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zong-Ying Liu
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Shu-Yi Si
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ze Yang
- The Key Lab of Geriatrics, Beijing Hospital and Beijing Institute of Geriatrics, Ministry of Health, Beijing, China
| | - Zhuo-Rong Li
- Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
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Effects of rosiglitazone on intramyocellular lipid accumulation in Psammomys obesus. Biochim Biophys Acta Mol Basis Dis 2010; 1802:235-9. [DOI: 10.1016/j.bbadis.2009.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2009] [Revised: 10/01/2009] [Accepted: 10/02/2009] [Indexed: 11/19/2022]
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Godoy-Matos AF, Bahia LR, Domingues RC, Tambascia M, Geloneze B, Kraemer-Aguiar LG, Bouskela E. Rosiglitazone decreases intra- to extramyocellular fat ratio in obese non-diabetic adults with metabolic syndrome. Diabet Med 2010; 27:23-9. [PMID: 20121885 DOI: 10.1111/j.1464-5491.2009.02868.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Insulin resistance is intrinsically related to intramyocellular (IMCL) rather than extramyocellular (EMCL) triglyceride content. Conflicting results have been reported on the ability of insulin sensitizer agents, such as thiazolidinediones, to modify muscle fat distribution. The aim of this study was to investigate the role of rosiglitazone on muscle fat compartment distribution in an adult population of obese non-diabetic metabolic syndrome patients. PATIENTS AND METHODS Fifteen obese, non-diabetic, metabolic syndrome patients were studied by means of proton nuclear magnetic resonance ((1)H-NMR) spectroscopy before and after treatment with rosiglitazone 8 mg/day for 6 months. Anthropometrical and metabolic variables were assessed. RESULTS After rosiglitazone, body weight and hip circumference increased [100.9 (91.12-138.7) vs. 107.0 (79.6-142.8) kg and 118 (107-126) vs. 122 (110-131) cm]; while waist-hip ratio (WHR) decreased from 0.93 (0.87-1.00) to 0.89 (0.82-0.97) (P < 0.001 for all). Additionally, fasting plasma glucose, insulin and homeostatis model assessment of insulin resistance (HOMA-IR) significantly decreased while adiponectin increased over threefold [9.7 (3.7-17.7) vs. 38.0 (19.3-42.4) microg/ml] without any changes in resistin. Finally, the IMCL did not change [267.54 (213.94-297.94) vs. 305.75 (230.80-424.75) arbitrary units (AU), P = 0.15] while the EMCL increased [275.53 (210.39-436.66) vs. 411.39 (279.92-556.59) AU; P < 0.01] therefore decreasing the IMCL-to-EMCL (IMCL/EMCL) ratio [1.07 (0.78-1.23) vs. 0.71 (0.53-0.96); P < 0.01]. CONCLUSION Rosiglitazone treatment increased body weight and hip circumference and decreased WHR. More importantly, it decreased the IMCL/EMCL ratio by increasing the EMCL without any significant change on the IMCL.
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Affiliation(s)
- A F Godoy-Matos
- State Institute of Diabetes and Endocrinology, IEDE, Rio de Janeiro, Brazil
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Affiliation(s)
- David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt Mouse Metabolic Phenotyping Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA.
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Nan YM, Fu N, Wu WJ, Liang BL, Wang RQ, Zhao SX, Zhao JM, Yu J. Rosiglitazone prevents nutritional fibrosis and steatohepatitis in mice. Scand J Gastroenterol 2009; 44:358-65. [PMID: 18991162 DOI: 10.1080/00365520802530861] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE Currently, no agent has been confirmed as preventing the fibrosing progression of non-alcoholic steatohepatitis (NASH). In this study, rosiglitazone was used in the clinical treatment of insulin resistance in patients with type 2 diabetes mellitus. However, its protective effect on non-alcoholic fibrosing steatohepatitis is not clear. The study aimed to elucidate the effect and the mechanism of rosiglitazone in inhibiting nutrition-related fibrosis in mice. METHODS C57BL6/J mice were fed a high fat, methionine-choline deficient (MCD) diet for 8 weeks to induce hepatic fibrosis, and rosiglitazone was given in the treated group. The effect of rosiglitazone was assessed by comparing the severity of hepatic fibrosis in liver sections, the activation of hepatic stellate cells (HSCs) and the expression of TGF-beta1 and connective tissue growth factor (CTGF). RESULTS At week 8, MCD-diet-induced fibrosing NASH models showed increased serum ALT and AST levels, severe hepatic steatosis, and infiltration of inflammation and fibrosis which, associated with down-regulated PPAR gamma mRNA and protein expression, up-regulated alpha-SMA protein expression and enhanced TGF-beta1, CTGF mRNA and protein expression. Rosiglitazone significantly lowered serum ALT and AST and it reduced MCD-induced fibrosis by repressing levels of alpha-SMA protein expression and pro-fibrosis factors TGF-beta1 and CTGF. It also restored expression of PPAR gamma. CONCLUSIONS The present study provides clear morphological and molecular biological evidence of the protective role of rosiglitazone in ameliorating nutritional fibrosing steatohepatitis. Rosiglitazone may ameliorate hepatic fibrosis by activating PPAR gamma, which can inhibit HSC activation and suppress TGF-beta1 and CTGF expression.
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Affiliation(s)
- Yue-Min Nan
- Department of Traditional and Western Medical Hepatology, Third Hospital of Hebei Medical University, Shijiazhuang, China.
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Kuda O, Jelenik T, Jilkova Z, Flachs P, Rossmeisl M, Hensler M, Kazdova L, Ogston N, Baranowski M, Gorski J, Janovska P, Kus V, Polak J, Mohamed-Ali V, Burcelin R, Cinti S, Bryhn M, Kopecky J. n-3 fatty acids and rosiglitazone improve insulin sensitivity through additive stimulatory effects on muscle glycogen synthesis in mice fed a high-fat diet. Diabetologia 2009; 52:941-951. [PMID: 19277604 DOI: 10.1007/s00125-009-1305-z] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 02/02/2009] [Indexed: 01/09/2023]
Abstract
AIMS/HYPOTHESIS Fatty acids of marine origin, i.e. docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) act as hypolipidaemics, but they do not improve glycaemic control in obese and diabetic patients. Thiazolidinediones like rosiglitazone are specific activators of peroxisome proliferator-activated receptor gamma, which improve whole-body insulin sensitivity. We hypothesised that a combined treatment with a DHA and EPA concentrate (DHA/EPA) and rosiglitazone would correct, by complementary additive mechanisms, impairments of lipid and glucose homeostasis in obesity. METHODS Male C57BL/6 mice were fed a corn oil-based high-fat diet. The effects of DHA/EPA (replacing 15% dietary lipids), rosiglitazone (10 mg/kg diet) or a combination of both on body weight, adiposity, metabolic markers and adiponectin in plasma, as well as on liver and muscle gene expression and metabolism were analysed. Euglycaemic-hyperinsulinaemic clamps were used to characterise the changes in insulin sensitivity. The effects of the treatments were also analysed in dietary obese mice with impaired glucose tolerance (IGT). RESULTS DHA/EPA and rosiglitazone exerted additive effects in prevention of obesity, adipocyte hypertrophy, low-grade adipose tissue inflammation, dyslipidaemia and insulin resistance, while inducing adiponectin, suppressing hepatic lipogenesis and decreasing muscle ceramide concentration. The improvement in glucose tolerance reflected a synergistic stimulatory effect of the combined treatment on muscle glycogen synthesis and its sensitivity to insulin. The combination treatment also reversed dietary obesity, dyslipidaemia and IGT. CONCLUSIONS/INTERPRETATION DHA/EPA and rosiglitazone can be used as complementary therapies to counteract dyslipidaemia and insulin resistance. The combination treatment may reduce dose requirements and hence the incidence of adverse side effects of thiazolidinedione therapy.
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Affiliation(s)
- O Kuda
- Department of Adipose Tissue Biology, Institute of Physiology of the Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Abstract
Adipose tissue is not an inert cell mass contributing only to the storage of fat, but a sophisticated ensemble of cellular components with highly specialized and complex functions. In addition to managing the most important energy reserve of the body, it secretes a multitude of soluble proteins called adipokines, which have beneficial or, alternatively, deleterious effects on the homeostasis of the whole body. The expression of these adipokines is an integrated response to various signals received from many organs, which depends heavily on the integrity and physiological status of the adipose tissue. One of the main regulators of gene expression in fat is the transcription factor peroxisome proliferator-activated receptor gamma (PPARgamma), which is a fatty acid- and eicosanoid-dependent nuclear receptor that plays key roles in the development and maintenance of the adipose tissue. Furthermore, synthetic PPARgamma agonists are therapeutic agents used in the treatment of type 2 diabetes.This review discusses recent knowledge on the link between fat physiology and metabolic diseases, and the roles of PPARgamma in this interplay via the regulation of lipid and glucose metabolism. Finally, we assess the putative benefits of targeting this nuclear receptor with still-to-be-identified highly selective PPARgamma modulators.
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Affiliation(s)
- Silvia I Anghel
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, Lausanne CH-1015, Switzerland
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Norris AW, Hirshman MF, Yao J, Jessen N, Musi N, Chen L, Sivitz WI, Goodyear LJ, Kahn CR. Endogenous peroxisome proliferator-activated receptor-gamma augments fatty acid uptake in oxidative muscle. Endocrinology 2008; 149:5374-83. [PMID: 18653710 PMCID: PMC2584586 DOI: 10.1210/en.2008-0100] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In the setting of insulin resistance, agonists of peroxisome proliferator-activated receptor (PPAR)-gamma restore insulin action in muscle and promote lipid redistribution. Mice with muscle-specific knockout of PPARgamma (MuPPARgammaKO) develop excess adiposity, despite reduced food intake and normal glucose disposal in muscle. To understand the relation between muscle PPARgamma and lipid accumulation, we studied the fuel energetics of MuPPARgammaKO mice. Compared with controls, MuPPARgammaKO mice exhibited significantly increased ambulatory activity, muscle mitochondrial uncoupling, and respiratory quotient. Fitting with this latter finding, MuPPARgammaKO animals compared with control siblings exhibited a 25% reduction in the uptake of the fatty acid tracer 2-bromo-palmitate (P < 0.05) and a 13% increase in serum nonesterified fatty acids (P = 0.05). These abnormalities were associated with no change in AMP kinase (AMPK) phosphorylation, AMPK activity, or phosphorylation of acetyl-CoA carboxylase in muscle and occurred despite increased expression of fatty acid transport protein 1. Palmitate oxidation was not significantly altered in MuPPARgammaKO mice despite the increased expression of several genes promoting lipid oxidation. These data demonstrate that PPARgamma, even in the absence of exogenous activators, is required for normal rates of fatty acid uptake in oxidative skeletal muscle via mechanisms independent of AMPK and fatty acid transport protein 1. Thus, when PPARgamma activity in muscle is absent or reduced, there will be decreased fatty acid disposal leading to diminished energy utilization and ultimately adiposity.
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Affiliation(s)
- Andrew W Norris
- Department of Pediatrics, University of Iowa, Iowa City, Iowa 52242, USA.
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Dallaire P, Bellmann K, Laplante M, Gélinas S, Centeno-Baez C, Penfornis P, Peyot ML, Latour MG, Lamontagne J, Trujillo ME, Scherer PE, Prentki M, Deshaies Y, Marette A. Obese mice lacking inducible nitric oxide synthase are sensitized to the metabolic actions of peroxisome proliferator-activated receptor-gamma agonism. Diabetes 2008; 57:1999-2011. [PMID: 18458147 PMCID: PMC2494686 DOI: 10.2337/db08-0540] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVE Synthetic ligands for peroxisome proliferator-activated receptor-gamma (PPAR-gamma) improve insulin sensitivity in obesity, but it is still unclear whether inflammatory signals modulate their metabolic actions. In this study, we tested whether targeted disruption of inducible nitric oxide (NO) synthase (iNOS), a key inflammatory mediator in obesity, modulates the metabolic effects of rosiglitazone in obese mice. RESEARCH DESIGN AND METHODS iNOS(-/-) and iNOS(+/+) were subjected to a high-fat diet or standard diet for 18 weeks and were then treated with rosiglitazone for 2 weeks. Whole-body insulin sensitivity and glucose tolerance were determined and metabolic tissues harvested to assess activation of insulin and AMP-activated protein kinase (AMPK) signaling pathways and the levels of inflammatory mediators. RESULTS Rosiglitazone was found to similarly improve whole-body insulin sensitivity and insulin signaling to Akt/PKB in skeletal muscle of obese iNOS(-/-) and obese iNOS(+/+) mice. However, rosiglitazone further improved glucose tolerance and liver insulin signaling only in obese mice lacking iNOS. This genotype-specific effect of rosiglitazone on glucose tolerance was linked to a markedly increased ability of the drug to raise plasma adiponectin levels. Accordingly, rosiglitazone increased AMPK activation in muscle and liver only in obese iNOS(-/-) mice. PPAR-gamma transcriptional activity was increased in adipose tissue of iNOS(-/-) mice. Conversely, treatment of 3T3-L1 adipocytes with a NO donor blunted PPAR-gamma activity. CONCLUSIONS Our results identify the iNOS/NO pathway as a critical modulator of PPAR-gamma activation and circulating adiponectin levels and show that invalidation of this key inflammatory mediator improves the efficacy of PPAR-gamma agonism in an animal model of obesity and insulin resistance.
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Affiliation(s)
- Patrice Dallaire
- Department of Anatomy and Physiology, Laval University, Québec, Québec, Canada
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Liu HY, Collins QF, Moukdar F, Zhuo D, Han J, Hong T, Collins S, Cao W. Suppression of hepatic glucose production by human neutrophil alpha-defensins through a signaling pathway distinct from insulin. J Biol Chem 2008; 283:12056-63. [PMID: 18347011 PMCID: PMC2335365 DOI: 10.1074/jbc.m801033200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Revised: 02/29/2008] [Indexed: 12/29/2022] Open
Abstract
In this study, we tested the hypothesis that human neutrophil alpha-defensins (HNPs) inhibit hepatic glucose production through a signaling pathway distinct from insulin. The effect of HNP-1 on fasting blood glucose levels and the expression of hepatic gluconeogenic genes was first examined. Using hyperinsulinemic-euglycemic clamps, we determined the effect of HNP-1 on endogenous glucose production, hepatic expression of key gluconeogenic genes and glucose uptake in skeletal muscle in Zucker diabetic fatty rats. In isolated primary hepatocytes, we studied the effect of HNP-1 and -2 on glucose production, expression of gluconeogenic genes, and phosphorylation of Akt, c-Src, and FoxO1. Our results show that HNP-1 reduced blood glucose levels of both normal mice and Zucker diabetic fatty rats predominantly through suppression of hepatic glucose production. HNPs inhibited glycogenolysis and gluconeogenesis in isolated hepatocytes. HNPs also suppressed expression of key gluconeogenic genes including phosphoenoylpyruvate carboxyl kinase and glucose-6-phosphatase. To investigate the mechanism, we found that HNPs stimulated phosphorylation of Akt and FoxO1 without activating IRS1. Nevertheless, HNPs activated c-Src. Blockade of c-Src activity with either a chemical inhibitor PP2 or an alternative inhibitor CSK prevented the inhibitory effect of HNPs on gluconeogenesis. Together, our results support the hypothesis that HNPs can suppress hepatic glucose production through an intracellular mechanism distinct from the classical insulin signaling pathway.
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Affiliation(s)
- Hui-Yu Liu
- Division of Translational Biology, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina 27709, USA
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41
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Sulistio MS, Zion A, Thukral N, Chilton R. PPARgamma agonists and coronary atherosclerosis. Curr Atheroscler Rep 2008; 10:134-41. [PMID: 18417068 DOI: 10.1007/s11883-008-0020-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The prevalence of type 2 diabetes mellitus (T2DM) is growing at an alarming rate and reaching epidemic proportions, and cardiovascular disease continues to be one of the leading causes of death in the United States. The key relationship between these two diseases (knowing that T2DM is a strong risk factor for cardiovascular disease) is insulin resistance and the detrimental effect it has on macrovasculature. Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor gammaagonists that are beneficial in the treatment of T2DM and have the added benefit of modifying lipid profiles. This review discusses the basic science linking insulin resistance to atherosclerosis and describes the major TZD trials in the recent literature. It also addresses the clinical implications of these studies and media scrutiny surrounding the recent controversial report that TZDs may be linked to an increased risk of myocardial infarction.
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Affiliation(s)
- Melanie S Sulistio
- University of Texas Health Science Center at San Antonio, Department of Cardiology, 7300 Medical Drive, San Antonio, TX 78229, USA.
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42
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Atsumi T, Cho YR, Leng L, McDonald C, Yu T, Danton C, Hong EG, Mitchell RA, Metz C, Niwa H, Takeuchi J, Onodera S, Umino T, Yoshioka N, Koike T, Kim JK, Bucala R. The proinflammatory cytokine macrophage migration inhibitory factor regulates glucose metabolism during systemic inflammation. THE JOURNAL OF IMMUNOLOGY 2007; 179:5399-406. [PMID: 17911626 DOI: 10.4049/jimmunol.179.8.5399] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Inflammation provokes significant abnormalities in host metabolism that result from the systemic release of cytokines. An early response of the host is hyperglycemia and resistance to the action of insulin, which progresses over time to increased glucose uptake in peripheral tissue. Although the cytokine TNF-alpha has been shown to exert certain catabolic effects, recent studies suggest that the metabolic actions of TNF-alpha occur by the downstream regulation of additional mediators, such as macrophage migration inhibitory factor (MIF). We investigated the glycemic responses of endotoxemic mice genetically deficient in MIF (MIF(-/-)). In contrast to wild-type mice, MIF(-/-) mice exhibit normal blood glucose and lactate responses following the administration of endotoxin, or TNF-alpha. MIF(-/-) mice also show markedly increased glucose uptake into white adipose tissue in vivo in the endotoxemic state. Treatment of adipocytes with MIF, or anti-MIF mAb, modulates insulin-mediated glucose transport and insulin receptor signal transduction; these effects include the phosphorylation of insulin receptor substrate-1, its association with the p85 regulatory subunit of PI3K, and the downstream phosphorylation of Akt. Genetic MIF deficiency also promotes adipogenesis, which is in accord with a downstream role for MIF in the action of TNF-alpha. These studies support an important role for MIF in host glucose metabolism during sepsis.
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Affiliation(s)
- Toshiya Atsumi
- Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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43
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Anghel SI, Bedu E, Vivier CD, Descombes P, Desvergne B, Wahli W. Adipose tissue integrity as a prerequisite for systemic energy balance: a critical role for peroxisome proliferator-activated receptor gamma. J Biol Chem 2007; 282:29946-57. [PMID: 17699161 DOI: 10.1074/jbc.m702490200] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) is an essential regulator of adipocyte differentiation, maintenance, and survival. Deregulations of its functions are associated with metabolic diseases. We show here that deletion of one PPARgamma allele not only affected lipid storage but, more surprisingly, also the expression of genes involved in glucose uptake and utilization, the pentose phosphate pathway, fatty acid synthesis, lipolysis, and glycerol export as well as in IR/IGF-1 signaling. These deregulations led to reduced circulating adiponectin levels and an energy crisis in the WAT, reflected in a decrease to nearly half of its intracellular ATP content. In addition, there was a decrease in the metabolic rate and physical activity of the PPARgamma(+/-) mice, which was abolished by thiazolidinedione treatment, thereby linking regulation of the metabolic rate and physical activity to PPARgamma. It is likely that the PPARgamma(+/-) phenotype was due to the observed WAT dysfunction, since the gene expression profiles associated with metabolic pathways were not affected either in the liver or the skeletal muscle. These findings highlight novel roles of PPARgamma in the adipose tissue and underscore the multifaceted action of this receptor in the functional fine tuning of a tissue that is crucial for maintaining the organism in good health.
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Affiliation(s)
- Silvia I Anghel
- Center for Integrative Genomics, National Research Center Frontiers in Genetics, University of Lausanne, Génopode Bldg., CH-1015 Lausanne, Switzerland
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44
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Berthiaume M, Laplante M, Tchernof A, Deshaies Y. Metabolic action of peroxisome proliferator-activated receptor γ agonism in rats with exogenous hypercorticosteronemia. Int J Obes (Lond) 2007; 31:1660-70. [PMID: 17579631 DOI: 10.1038/sj.ijo.0803668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE The beneficial metabolic actions of peroxisome proliferator-activated receptor gamma (PPARgamma) agonism are associated with modifications in adipose tissue metabolism that include a reduction in local glucocorticoid (GC) production by 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1). This study aimed to assess the contribution of GC attenuation to PPARgamma agonism action on gene expression in visceral adipose tissue and global metabolic profile. DESIGN Rats were treated (2 weeks) with the PPARgamma agonist rosiglitazone (RSG, 10 mg/kg/day) with concomitant infusion of vehicle (cholesterol implant) or corticosterone (HiCORT, 75 mg/implant/week) to defeat PPARgamma-mediated GC attenuation. MEASUREMENTS mRNA levels of enzymes involved in lipid uptake (and lipoprotein lipase activity), storage, lipolysis, recycling, and oxidation in retroperitoneal white adipose tissue (RWAT). Serum glucose, insulin and lipids, and lipid content of oxidative tissues. RESULTS Whereas HiCORT did not alter RWAT mass, RSG increased the latter (+33%) independently of the corticosterone status. Both HiCORT and RSG increased lipoprotein lipase activity, the mRNA levels of the de novo lipogenesis enzyme fatty acid synthase, and that of the fatty acid retention-promoting enzyme acyl-CoA synthase 1, albeit in a nonadditive fashion. Expression level of the lipolysis enzyme adipose triglyceride lipase was increased additively by HiCORT and RSG. PPARgamma agonism increased mRNA of the fatty acid recycling enzymes glycerol kinase and cytosolic phosphoenolpyruvate carboxykinase and those of the fatty acid oxidation enzymes muscle-type carnitine palmitoyltransferase 1 and acyl-CoA oxidase, whereas HiCORT remained without effect. HiCORT resulted in liver steatosis and hyperinsulinemia, which were abrogated by RSG, whereas the HiCORT-induced elevation in serum nonesterified fatty acid levels was only partially prevented. The hypotriglyceridemic action of RSG was maintained in HiCORT rats. CONCLUSION The GC and PPARgamma pathways exert both congruent and opposite actions on specific aspects of adipose tissue metabolism. Both the modulation of adipose gene expression and the beneficial global metabolic actions of PPARgamma agonism are retained under imposed high ambient GC, and are therefore independent from PPARgamma effects on 11beta-HSD1-mediated GC production.
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Affiliation(s)
- M Berthiaume
- Faculty of Medicine, Laval Hospital Research Center, Laval University, Québec, Québec, Canada
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45
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Abstract
Although abnormal glucose metabolism defines type 2 diabetes mellitus (T2DM) and accounts for many of its symptoms and complications, efforts to understand the pathogenesis of T2DM are increasingly focused on disordered lipid metabolism. Here we review recent human studies exploring the mechanistic links between disorders of fatty acid/lipid metabolism and insulin resistance. As "mouse models of insulin resistance" were comprehensively reviewed in Physiological Reviews by Nandi et al. in 2004, we will concentrate on human studies involving the use of isotopes and/or magnetic resonance spectroscopy, occasionally drawing on mouse models which provide additional mechanistic insight.
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Affiliation(s)
- David B. Savage
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
| | - Kitt Falk Petersen
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
| | - Gerald I. Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06536-8012
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, 06536-8012
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46
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Rojas-Rodríguez J, Escobar-Linares LE, Garcia-Carrasco M, Escárcega RO, Fuentes-Alexandro S, Zamora-Ustaran A. The relationship between the metabolic syndrome and energy-utilization deficit in the pathogenesis of obesity-induced osteoarthritis. Med Hypotheses 2007; 69:860-8. [PMID: 17368954 DOI: 10.1016/j.mehy.2007.01.075] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 01/13/2007] [Indexed: 11/20/2022]
Abstract
We propose that the pathogenesis of obesity-induced osteoarthritis may be explained by the metabolic changes in the striated muscle induced by the interaction of insulin resistance and systemic inflammation in obese individuals with metabolic syndrome being osteoarthritis the latest consequence by the physiological changes seen in the metabolic syndrome. Increased levels of TH1 cytokines are produced by activated macrophages in the presence of an acute or chronic infectious disease and suppress the sensitivity of insulin receptors on the membrane of muscle cell and adipocytes. Both cells are activated by inflammatory cytokines and contribute to enhance acute inflammation and to maintain a state of chronic, low-grade inflammation in apparently healthy obese individuals. The increased number of macrophage in the adipose tissue of obese individuals acts as an amplifier of inflammation. Patients with osteoarthritis and metabolic syndrome frequently are complaining about hotness and recurrent edema of feet and hands. It is probable that hyperinsulinemia in the presence of insulin resistance and inflammation, induce vasodilation through the TNF mediated-iNOS overexpression. Patients with metabolic syndrome express clinically the consequence of a poor uptake, storage and energy expenditure by the muscle and any other insulin dependent tissue and the consequence of high insulin plasma levels are vasodilation and increased protein synthesis. The fatigue and muscle weakness induced by insulin resistance and inflammation in obese patients with metabolic syndrome increase the frequency and the intensity of traumatic events of peripheral or axial joints that result in stretch and breaking of tenoperiosteal junction and abrasive damage of cartilage and therefore in these patients with metabolic syndrome and pro-inflammatory state the reparative process of cartilage and periarticular tissues would be severely modified by the growth factor activity in presence of high levels of insulin.
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Affiliation(s)
- Jorge Rojas-Rodríguez
- Rheumatology Department, Benemérita Universidad Autónoma de Puebla, School of Medicine, Puebla, Mexico
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47
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den Boer MAM, Voshol PJ, Kuipers F, Romijn JA, Havekes LM. Hepatic glucose production is more sensitive to insulin-mediated inhibition than hepatic VLDL-triglyceride production. Am J Physiol Endocrinol Metab 2006; 291:E1360-4. [PMID: 16849628 DOI: 10.1152/ajpendo.00188.2006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin is an important inhibitor of both hepatic glucose output and hepatic VLDL-triglyceride (VLDL-TG) production. We investigated whether both processes are equally sensitive to insulin-mediated inhibition. To test this, we used euglycemic clamp studies with four increasing plasma concentrations of insulin in wild-type C57Bl/6 mice. By extrapolation, we estimated that half-maximal inhibition of hepatic glucose output and hepatic VLDL-TG production by insulin were obtained at plasma insulin levels of approximately 3.6 and approximately 6.8 ng/ml, respectively. In the same experiments, we measured that half-maximal decrease of plasma free fatty acid levels and half-maximal stimulation of peripheral glucose uptake were reached at plasma insulin levels of approximately 3.0 and approximately 6.0 ng/ml, respectively. We conclude that, compared with insulin sensitivity of hepatic glucose output, peripheral glucose uptake and hepatic VLDL-TG production are less sensitive to insulin.
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Affiliation(s)
- Marion A M den Boer
- Dept. of Endocrinology and Metabolism, Leiden University Medical Center, 2333 ZA, Leiden, The Netherlands.
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48
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Qi Y, Nie Z, Lee YS, Singhal NS, Scherer PE, Lazar MA, Ahima RS. Loss of resistin improves glucose homeostasis in leptin deficiency. Diabetes 2006; 55:3083-90. [PMID: 17065346 DOI: 10.2337/db05-0615] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Resistin levels are increased in obesity, and hyperresistinemia impairs glucose homeostasis in rodents. Here, we have determined the role of resistin in ob/ob mice that are obese and insulin resistant because of genetic deficiency of leptin. Loss of resistin increased obesity in ob/ob mice by further lowering the metabolic rate without affecting food intake. Nevertheless, resistin deficiency improved glucose tolerance and insulin sensitivity in these severely obese mice, largely by enhancing insulin-mediated glucose disposal in muscle and adipose tissue. In contrast, in C57BL/6J mice with diet-induced obesity but wild-type leptin alleles, resistin deficiency reduced hepatic glucose production and increased peripheral glucose uptake. Resistin deficiency enhanced Akt phosphorylation in muscle and liver and decreased suppressor of cytokine signaling-3 level in muscle, and these changes were reversed by resistin replacement. Together, these results provide strong support for an important role of resistin in insulin resistance and diabetes associated with genetic or diet-induced obesity.
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Affiliation(s)
- Yong Qi
- University of Pennsylvania School of Medicine, Division of Endocrinology, DiabetesMetabolism, 764 Clinical Research Building, 415 Curie Blvd., Philadelphia, PA 19104, USA
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Blaschke F, Caglayan E, Hsueh WA. Peroxisome proliferator-activated receptor gamma agonists: their role as vasoprotective agents in diabetes. Endocrinol Metab Clin North Am 2006; 35:561-74, ix. [PMID: 16959586 DOI: 10.1016/j.ecl.2006.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Both type 1 and type 2 diabetes melitius are associated with increased cardiovascular morbidity, and now affect more than 170 million individuals worldwide. The incidence of type 2 diabetes is growing rapidly and now accounts for 90 to 95 percent of all diabetes cases. Thiazolidinediones (TZDs) a class of insulin sensitizing agents commonly used in the treatment of patients who have type 2 diabetes, improve endothelial dysfunction and exert beneficial effects on lipid profiles by activating the nuclear receptor peroxisome proliferator-activated receptor gamma (PPAR-gamma). In addition, TZDs exhibit antiatherogenic effects, independent of their antidiabetic and lipid-lowering properties, by attenuating proinflammatory processes. The combination of increased insulin sensitivity, improved lipid profile, and reduced inflammation may explain the cardiovascular benefits of this class of drugs
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Affiliation(s)
- Florian Blaschke
- Department of Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Diabetes and Hypertension, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
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50
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Savkur RS, Miller AR. Investigational PPAR-gamma agonists for the treatment of Type 2 diabetes. Expert Opin Investig Drugs 2006; 15:763-78. [PMID: 16787140 DOI: 10.1517/13543784.15.7.763] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The tremendous increase in the global prevalence of Type 2 diabetes (T2D) and its conglomeration of metabolic disorders has dramatically intensified the search for innovative therapies to fight this emerging epidemic. Over the last decade, the family of nuclear receptors, especially the peroxisome proliferator-activated receptors (PPARs), has emerged as one of the most important drug targets aimed at combating the metabolic syndrome. Consequently, compounds that activate the PPARs have served as potential therapeutics for the treatment of T2D and the metabolic anomalies associated with this disorder. This review focuses on the currently marketed compounds and also describes the discovery and development of the next generation of PPAR ligands that are under investigation for the potential treatment of T2D and the metabolic syndrome.
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MESH Headings
- Adipocytes/metabolism
- Animals
- Cardiovascular Diseases/chemically induced
- Clinical Trials as Topic
- Cricetinae
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/metabolism
- Drug Design
- Drug Evaluation, Preclinical
- Drugs, Investigational/pharmacology
- Drugs, Investigational/therapeutic use
- Drugs, Investigational/toxicity
- Dyslipidemias/drug therapy
- Gene Expression Regulation/drug effects
- Glucose/metabolism
- Humans
- Hypoglycemic Agents/pharmacology
- Hypoglycemic Agents/therapeutic use
- Hypolipidemic Agents/pharmacology
- Hypolipidemic Agents/therapeutic use
- Insulin/metabolism
- Insulin Resistance
- Insulin Secretion
- Islets of Langerhans/drug effects
- Islets of Langerhans/metabolism
- Lipid Metabolism/drug effects
- Metabolic Syndrome/complications
- Metabolic Syndrome/drug therapy
- Metabolic Syndrome/metabolism
- Mice
- Mice, Mutant Strains
- Muscle Cells/metabolism
- Organ Specificity
- PPAR alpha/agonists
- PPAR delta/agonists
- PPAR delta/physiology
- PPAR gamma/agonists
- PPAR gamma/chemistry
- PPAR gamma/physiology
- Protein Isoforms/drug effects
- Protein Isoforms/physiology
- Rats
- Rats, Sprague-Dawley
- Rats, Zucker
- Weight Gain/drug effects
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Affiliation(s)
- Rajesh S Savkur
- Eli Lilly and Company, Diabetes Research, Lilly Research Laboratories, Indianapolis, IN 46285, USA
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