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McAleer JP. Obesity and the microbiome in atopic dermatitis: Therapeutic implications for PPAR-γ agonists. Front Allergy 2023; 4:1167800. [PMID: 37051264 PMCID: PMC10083318 DOI: 10.3389/falgy.2023.1167800] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/13/2023] [Indexed: 03/29/2023] Open
Abstract
Atopic dermatitis (AD) is an inflammatory skin disease characterized by epidermal barrier disruption, Th2 immune responses to skin allergens and microbial dysbiosis within affected lesions. Studies within the past decade have revealed genetic and environmental factors contributing to AD in children. Obesity is a metabolic disorder that often manifests early in life and is associated with reduced bacterial diversity, leading to skin colonization with lipophilic bacteria and intestinal colonization with pro-inflammatory species. These changes impair epithelial barriers and promote Th17 responses, which may worsen the severity of AD symptoms. While few studies have examined the contribution of microbiota in obesity-induced allergies, there is emerging evidence that PPAR-γ may be an effective therapeutic target. This review discusses the microbiome in pediatric AD, treatment with probiotics, how disease is altered by obesity and potential therapeutic effects of PPAR-γ agonists. While healthy skin contains diverse species adapted for specific niches, lesional skin is highly colonized with Staphylococcus aureus which perpetuates the inflammatory reaction. Treatments for AD should help to restore microbial diversity in the skin and intestine, as well as epithelial barrier function. Pre-clinical models have shown that PPAR-γ agonists can suppress Th17 responses, IgE production and mast cell function, while improving the epidermal barrier and microbial homeostasis. Overall, PPAR-γ agonists may be effective in a subset of patients with AD, and future studies should distinguish their metabolic and anti-inflammatory effects in order to inform the best therapies.
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2
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Rochford JJ. When Adipose Tissue Lets You Down: Understanding the Functions of Genes Disrupted in Lipodystrophy. Diabetes 2022; 71:589-598. [PMID: 35316838 DOI: 10.2337/dbi21-0006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 12/22/2021] [Indexed: 11/13/2022]
Abstract
Lipodystrophy syndromes are conditions in which the adipose tissue mass of an individual is altered inappropriately. The change in adipose mass can range from a relatively modest and subtle redistribution in some individuals with partial lipodystrophy to a near-complete absence of adipose tissue in the most severe forms of generalized lipodystrophy. The common feature is a disconnection between the need of the individual for a safe, healthy lipid storage capacity and the available adipose mass to perform this critical role. The inability to partition lipids for storage in appropriately functioning adipocytes leads to lipid accumulation in other tissues, which typically results in conditions such as diabetes, dyslipidemia, fatty liver, and cardiovascular disease. Several genes have been identified whose disruption leads to inherited forms of lipodystrophy. There is a link between some of these genes and adipose dysfunction, so the molecular basis of disease pathophysiology appears clear. However, for other lipodystrophy genes, it is not evident why their disruption should affect adipose development or function or, in the case of partial lipodystrophy, why only some adipose depots should be affected. Elucidating the molecular functions of these genes and their cellular and physiological effects has the capacity to uncover fundamental new insights regarding the development and functions of adipose tissue. This information is also likely to inform better management of lipodystrophy and improved treatments for patients. In addition, the findings will often be relevant to other conditions featuring adipose tissue dysfunction, including the more common metabolic disease associated with obesity.
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3
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Mušo M, Bentley L, Vizor L, Yon M, Burling K, Barker P, Zolkiewski LAK, Cox RD, Dumbell R. A Wars2 mutant mouse shows a sex and diet specific change in fat distribution, reduced food intake and depot-specific upregulation of WAT browning. Front Physiol 2022; 13:953199. [PMID: 36091365 PMCID: PMC9452902 DOI: 10.3389/fphys.2022.953199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Accepted: 07/19/2022] [Indexed: 11/21/2022] Open
Abstract
Background: Increased waist-to-hip ratio (WHR) is associated with increased mortality and risk of type 2 diabetes and cardiovascular disease. The TBX15-WARS2 locus has consistently been associated with increased WHR. Previous study of the hypomorphic Wars2 V117L/V117L mouse model found phenotypes including severely reduced fat mass, and white adipose tissue (WAT) browning, suggesting Wars2 could be a potential modulator of fat distribution and WAT browning. Methods: To test for differences in browning induction across different adipose depots of Wars2 V117L/V117L mice, we measured multiple browning markers of a 4-month old chow-fed cohort in subcutaneous and visceral WAT and brown adipose tissue (BAT). To explain previously observed fat mass loss, we also tested for the upregulation of plasma mitokines FGF21 and GDF15 and for differences in food intake in the same cohort. Finally, to test for diet-associated differences in fat distribution, we placed Wars2 V117L/V117L mice on low-fat or high-fat diet (LFD, HFD) and assessed their body composition by Echo-MRI and compared terminal adipose depot weights at 6 months of age. Results: The chow-fed Wars2 V117L/V117L mice showed more changes in WAT browning marker gene expression in the subcutaneous inguinal WAT depot (iWAT) than in the visceral gonadal WAT depot (gWAT). These mice also demonstrated reduced food intake and elevated plasma FGF21 and GDF15, and mRNA from heart and BAT. When exposed to HFD, the Wars2 V117L/V117L mice showed resistance to diet-induced obesity and a male and HFD-specific reduction of gWAT: iWAT ratio. Conclusion: Severe reduction of Wars2 gene function causes a systemic phenotype which leads to upregulation of FGF21 and GDF15, resulting in reduced food intake and depot-specific changes in browning and fat mass.
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Affiliation(s)
- Milan Mušo
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, United Kingdom
| | - Liz Bentley
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, United Kingdom.,Mary Lyon Centre at MRC Harwell, Oxfordshire, United Kingdom
| | - Lucie Vizor
- Mary Lyon Centre at MRC Harwell, Oxfordshire, United Kingdom
| | - Marianne Yon
- Mary Lyon Centre at MRC Harwell, Oxfordshire, United Kingdom
| | - Keith Burling
- MRC Metabolic Diseases Unit, Mouse Biochemistry Laboratory, Cambridge, United Kingdom
| | - Peter Barker
- MRC Metabolic Diseases Unit, Mouse Biochemistry Laboratory, Cambridge, United Kingdom
| | | | - Roger D Cox
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, United Kingdom
| | - Rebecca Dumbell
- Mammalian Genetics Unit, MRC Harwell Institute, Oxfordshire, United Kingdom.,Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
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4
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Corrales P, Vidal-Puig A, Medina-Gómez G. Obesity and pregnancy, the perfect metabolic storm. Eur J Clin Nutr 2021; 75:1723-1734. [PMID: 33911209 DOI: 10.1038/s41430-021-00914-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 03/15/2021] [Accepted: 03/29/2021] [Indexed: 02/02/2023]
Abstract
Pregnancy is a physiological stress that requires dynamic, regulated changes affecting maternal and fetal adiposity. Excessive accumulation of dysfunctional adipose tissue defined by metabolic and molecular alterations cause severe health consequences for mother and fetus. When subjected to sustained overnutrition, the cellular and lipid composition of the adipose tissue changes predisposing to insulin resistance, diabetes, and other metabolic disorders compromising the outcome of the pregnancy. Moreover, excessive maternal weight gain, usually in the context of obesity, predisposes to an increased flux of nutrients from mother to fetus throughout the placenta. The fetus of an obese mother will accumulate more adiposity and may increase the risk of future metabolic disorder later in life. Thus, further understanding of the interaction between maternal metabolism, epigenetic regulation of the adipose tissue, and their transgenerational transfer are required to mitigate the adverse health outcomes for the mother and the fetus associated with maternal obesity.
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Affiliation(s)
- Patricia Corrales
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Madrid, Spain.
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
- Wellcome Trust Sanger Institute, Hinxton, UK
- Cambridge University Nanjing Centre of Technology and Innovation, Nanjing, PR China
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Madrid, Spain.
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5
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Gautheron J, Morisseau C, Chung WK, Zammouri J, Auclair M, Baujat G, Capel E, Moulin C, Wang Y, Yang J, Hammock BD, Cerame B, Phan F, Fève B, Vigouroux C, Andreelli F, Jeru I. EPHX1 mutations cause a lipoatrophic diabetes syndrome due to impaired epoxide hydrolysis and increased cellular senescence. eLife 2021; 10:68445. [PMID: 34342583 PMCID: PMC8331186 DOI: 10.7554/elife.68445] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/23/2021] [Indexed: 12/11/2022] Open
Abstract
Epoxide hydrolases (EHs) regulate cellular homeostasis through hydrolysis of epoxides to less-reactive diols. The first discovered EH was EPHX1, also known as mEH. EH functions remain partly unknown, and no pathogenic variants have been reported in humans. We identified two de novo variants located in EPHX1 catalytic site in patients with a lipoatrophic diabetes characterized by loss of adipose tissue, insulin resistance, and multiple organ dysfunction. Functional analyses revealed that these variants led to the protein aggregation within the endoplasmic reticulum and to a loss of its hydrolysis activity. CRISPR-Cas9-mediated EPHX1 knockout (KO) abolished adipocyte differentiation and decreased insulin response. This KO also promoted oxidative stress and cellular senescence, an observation confirmed in patient-derived fibroblasts. Metreleptin therapy had a beneficial effect in one patient. This translational study highlights the importance of epoxide regulation for adipocyte function and provides new insights into the physiological roles of EHs in humans.
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Affiliation(s)
- Jeremie Gautheron
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Christophe Morisseau
- Department of Entomology and Nematology, and UC Davis Comprehensive Cancer Center, University of California, Davis, Davis, United States
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, United States.,Deparment of Medicine, Columbia University Irving Medical Center, New York, United States
| | - Jamila Zammouri
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Martine Auclair
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Genevieve Baujat
- Service de Génétique Clinique, Hôpital Necker-Enfants Malades, AP-HP, Paris, France
| | - Emilie Capel
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Celia Moulin
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
| | - Yuxin Wang
- Department of Entomology and Nematology, and UC Davis Comprehensive Cancer Center, University of California, Davis, Davis, United States
| | - Jun Yang
- Department of Entomology and Nematology, and UC Davis Comprehensive Cancer Center, University of California, Davis, Davis, United States
| | - Bruce D Hammock
- Department of Entomology and Nematology, and UC Davis Comprehensive Cancer Center, University of California, Davis, Davis, United States
| | - Barbara Cerame
- Goryeb Children's Hospital, Atlantic Health Systems, Morristown Memorial Hospital, Morristown, United States
| | - Franck Phan
- Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Service de Diabétologie-Métabolisme, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France.,Sorbonne Université-Inserm UMRS_1269, Paris, France
| | - Bruno Fève
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service de Diabétologie et Endocrinologie de la Reproduction, Hôpital Saint-Antoine, AP-HP, Paris, France
| | - Corinne Vigouroux
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Centre National de Référence des Pathologies Rares de l'Insulino-Sécrétion et de l'Insulino-Sensibilité (PRISIS), Service de Diabétologie et Endocrinologie de la Reproduction, Hôpital Saint-Antoine, AP-HP, Paris, France.,Laboratoire commun de Biologie et Génétique Moléculaires, Hôpital Saint-Antoine, AP-HP, Paris, France
| | - Fabrizio Andreelli
- Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Service de Diabétologie-Métabolisme, Hôpital Pitié-Salpêtrière, AP-HP, Paris, France.,Sorbonne Université-Inserm UMRS_1269, Paris, France
| | - Isabelle Jeru
- Sorbonne Université-Inserm UMRS_938, Centre de Recherche Saint-Antoine (CRSA), Paris, France.,Institute of Cardiometabolism and Nutrition (ICAN), CHU Pitié-Salpêtrière - Saint-Antoine, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France.,Laboratoire commun de Biologie et Génétique Moléculaires, Hôpital Saint-Antoine, AP-HP, Paris, France
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Alvarez-Guaita A, Patel S, Lim K, Haider A, Dong L, Conway OJ, Ma MKL, Chiarugi D, Saudek V, O'Rahilly S, Savage DB. Phenotypic characterization of Adig null mice suggests roles for adipogenin in the regulation of fat mass accrual and leptin secretion. Cell Rep 2021; 34:108810. [PMID: 33691105 PMCID: PMC7966854 DOI: 10.1016/j.celrep.2021.108810] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/23/2020] [Accepted: 02/09/2021] [Indexed: 12/25/2022] Open
Abstract
Adipogenin (Adig) is an adipocyte-enriched transmembrane protein. Its expression is induced during adipogenesis in rodent cells, and a recent genome-wide association study associated body mass index (BMI)-adjusted leptin levels with the ADIG locus. In order to begin to understand the biological function of Adig, we studied adipogenesis in Adig-deficient cultured adipocytes and phenotyped Adig null (Adig-/-) mice. Data from Adig-deficient cells suggest that Adig is required for adipogenesis. In vivo, Adig-/- mice are leaner than wild-type mice when fed a high-fat diet and when crossed with Ob/Ob hyperphagic mice. In addition to the impact on fat mass accrual, Adig deficiency also reduces fat-mass-adjusted plasma leptin levels and impairs leptin secretion from adipose explants, suggesting an additional impact on the regulation of leptin secretion.
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Affiliation(s)
- Anna Alvarez-Guaita
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Satish Patel
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Koini Lim
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Afreen Haider
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Liang Dong
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Olivia J Conway
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Marcella K L Ma
- MRC Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Genomics and Transcriptomics Core, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK
| | - Davide Chiarugi
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Vladimir Saudek
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - Stephen O'Rahilly
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK
| | - David B Savage
- Metabolic Research Laboratories, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, Cambridgeshire CB2 0QQ, UK.
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7
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Polyzos SA, Perakakis N, Mantzoros CS. Fatty liver in lipodystrophy: A review with a focus on therapeutic perspectives of adiponectin and/or leptin replacement. Metabolism 2019; 96:66-82. [PMID: 31071311 DOI: 10.1016/j.metabol.2019.05.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/23/2019] [Accepted: 05/03/2019] [Indexed: 01/17/2023]
Abstract
Lipodystrophy is a group of clinically heterogeneous, inherited or acquired, disorders characterized by complete or partial absence of subcutaneous adipose tissue that may occur simultaneously with the pathological, ectopic, accumulation of fat in other regions of the body, including the liver. Fatty liver adds significantly to hepatic and extra-hepatic morbidity in patients with lipodystrophy. Lipodystrophy is strongly associated with severe insulin resistance and related comorbidities, such as hyperglycemia, hyperlipidemia and nonalcoholic fatty liver disease (NAFLD), but other hepatic diseases may co-exist in some types of lipodystrophy, including autoimmune hepatitis in acquired lipodystrophies, or viral hepatitis in human immunodeficiency virus (HIV)-associated lipodystrophy. The aim of this review is to summarize evidence linking lipodystrophy with hepatic disease and to provide a special focus on potential therapeutic perspectives of leptin replacement therapy and adiponectin upregulation in lipodystrophy.
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Affiliation(s)
- Stergios A Polyzos
- First Department of Pharmacology, Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
| | - Nikolaos Perakakis
- Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Christos S Mantzoros
- Department of Internal Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Section of Endocrinology, Boston VA Healthcare System, Harvard Medical School, Boston, MA, USA
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8
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Broekema M, Savage D, Monajemi H, Kalkhoven E. Gene-gene and gene-environment interactions in lipodystrophy: Lessons learned from natural PPARγ mutants. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:715-732. [DOI: 10.1016/j.bbalip.2019.02.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/13/2019] [Accepted: 02/02/2019] [Indexed: 12/13/2022]
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9
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Wang K, Li F, Wang C, Deng Y, Cao Z, Cui Y, Xu K, Ln P, Sun Y. Serum Levels of Meteorin-Like (Metrnl) Are Increased in Patients with Newly Diagnosed Type 2 Diabetes Mellitus and Are Associated with Insulin Resistance. Med Sci Monit 2019; 25:2337-2343. [PMID: 30928991 PMCID: PMC6454984 DOI: 10.12659/msm.915331] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Meteorin-like (Metrnl) is a novel adipomyokine that may improve glucose tolerance and affect insulin resistance. This study aimed to investigate the association between serum levels of Metrnl with blood glucose status and to its association with insulin resistance. MATERIAL AND METHODS The study included 160 subjects with normal glucose tolerance (NGT) (n=40), impaired fasting glucose (IFG) (n=40), impaired glucose tolerance (IGT) (n=40), and newly diagnosed type 2 diabetes mellitus (T2DM) (n=40). An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum levels of Metrnl. Partial correlation analysis was used to analyze the relationship between serum levels of Metrnl and metabolic parameters. Multiple logistic regression analysis was performed to identify the association between serum levels of Metrnl with the risk of diabetes. RESULTS Serum levels of Metrnl was highest in patients with T2DM and significantly increased in patients with prediabetes compared with individuals with NGT. After adjusting for age, gender, and body mass index (BMI), serum Metrnl level was significantly correlated with lipid profile, glucose profile, and insulin resistance. Multiple logistic regression analysis showed that Metrnl significantly increased the risk of T2DM (OR=1.727; P=0.008) before adjusting for the homeostatic model assessment of insulin resistance (HOMA-IR). When further adjusted for HOMA-IR, Metrnl was no longer associated with an increased OR for T2DM (OR=1.491; P=0.066), while the HOMA-IR significantly increased the risk of T2DM (OR=1.935; P=0.008). CONCLUSIONS Serum levels of Metrnl were significantly increased in patients with T2DM and may increase the risk of T2DM independent of insulin resistance.
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Affiliation(s)
- Kexin Wang
- Department of General Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
| | - Fangna Li
- Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China (mainland).,Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
| | - Chuan Wang
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
| | - Yang Deng
- Department of Endocrinology, Shouguang Peoples' Hospital, Shouguang, Shandong, China (mainland)
| | - Zhenzhen Cao
- Department of Endocrinology, The First Peoples' Hospital of Pingyuan County, Pingyuan, Shandong, China (mainland)
| | - Yixin Cui
- Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China (mainland).,Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
| | - Kai Xu
- Department of General Surgery, Qilu Hospital of Shandong University, JinanJinan, Shandong, China (mainland).,Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China (mainland)
| | - Peng Ln
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
| | - Yu Sun
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, Shandong, China (mainland)
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Rodriguez‐Cuenca S, Carobbio S, Barceló‐Coblijn G, Prieur X, Relat J, Amat R, Campbell M, Dias AR, Bahri M, Gray SL, Vidal‐Puig A. P465L-PPARγ mutation confers partial resistance to the hypolipidaemic action of fibrates. Diabetes Obes Metab 2018; 20:2339-2350. [PMID: 29790245 PMCID: PMC6589924 DOI: 10.1111/dom.13370] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/04/2018] [Accepted: 05/12/2018] [Indexed: 12/13/2022]
Abstract
AIMS Familial partial lipodystrophic syndrome 3 (FPLD3) is associated with mutations in the transcription factor PPARγ. One of these mutations, the P467L, confers a dominant negative effect. We and others have previously investigated the pathophysiology associated with this mutation using a humanized mouse model that recapitulates most of the clinical symptoms observed in patients who have been phenotyped under different experimental conditions. One of the key clinical manifestations observed, both in humans and mouse models, is the ectopic accumulation of fat in the liver. With this study we aim to dissect the molecular mechanisms that contribute to the excessive accumulation of lipids in the liver and characterize the negative effect of this PPARγ mutation on the activity of PPARα in vivo when activated by fibrates. MATERIAL AND METHODS P465L-PPAR mutant and wild-type mice were divided into 8 experimental groups, 4 different conditions per genotype. Briefly, mice were fed a chow diet or a high-fat diet (HFD 45% Kcal from fat) for a period of 28 days and treated with WY14643 or vehicle for five days before culling. At the end of the experiment, tissues and plasma were collected. We performed extensive gene expression, fatty acid composition and histological analysis in the livers. The serum collected was used to measure several metabolites and to perform basic lipoprotein profile. RESULTS P465L mice showed increased levels of insulin and free fatty acids (FFA) as well as increased liver steatosis. They also exhibit decreased levels of very low density lipoproteins (VLDL) when fed an HFD. We also provide evidence of impaired expression of a number of well-established PPARα target genes in the P465L mutant livers. CONCLUSION Our data demonstrate that P465L confers partial resistance to the hypolipidemic action of fibrates. These results show that the fatty liver phenotype observed in P465L mutant mice is not only the consequence of dysfunctional adipose tissue, but also involves defective liver metabolism. All in all, the deleterious effects of P465L-PPARγ mutation may be magnified by their collateral negative effect on PPARα function.
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Affiliation(s)
- Sergio Rodriguez‐Cuenca
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
| | - Stefania Carobbio
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
- Wellcome Trust Sanger Institute, Wellcome Trust Genome CampusHinxtonUK
| | - Gwendolyn Barceló‐Coblijn
- Institut d'Investigació Sanitària Illes Balears (IdISBa, Balearic Islands Health Research Institute)PalmaSpain
| | - Xavier Prieur
- Département des Sciences de la Vie, L'Institut du Thorax, INSERM, CNRSUniversité de NantesNantesFrance
| | - Joana Relat
- Department of Nutrition, Food Science and Gastronomy, School of Pharmacy and Food Science, Food and Nutrition Torribera Campus. University of Barcelona (UB), Santa Coloma de Gramenet (Spain); INSA‐UB, Nutrition and Food Safety Research InstituteUniversity of BarcelonaBarcelonaSpain
| | - Ramon Amat
- Cell Signaling Unit, Departament de Ciències Experimentals i de la SalutUniversitat Pompeu Fabra (UPF)BarcelonaSpain
| | - Mark Campbell
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
| | - Ana Rita Dias
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
| | - Myriam Bahri
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
- Wellcome Trust Sanger Institute, Wellcome Trust Genome CampusHinxtonUK
| | - Sarah L. Gray
- Northern Medical ProgramUniversity of Northern British ColumbiaPrince GeorgeCanada
| | - Antonio Vidal‐Puig
- University of Cambridge Metabolic Research Laboratories, Level 4Wellcome Trust‐MRC Institute of Metabolic ScienceCambridgeUK
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11
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Corrales P, Vidal-Puig A, Medina-Gómez G. PPARs and Metabolic Disorders Associated with Challenged Adipose Tissue Plasticity. Int J Mol Sci 2018; 19:ijms19072124. [PMID: 30037087 PMCID: PMC6073677 DOI: 10.3390/ijms19072124] [Citation(s) in RCA: 102] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 07/13/2018] [Accepted: 07/18/2018] [Indexed: 02/07/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are members of a family of nuclear hormone receptors that exert their transcriptional control on genes harboring PPAR-responsive regulatory elements (PPRE) in partnership with retinoid X receptors (RXR). The activation of PPARs coordinated by specific coactivators/repressors regulate networks of genes controlling diverse homeostatic processes involving inflammation, adipogenesis, lipid metabolism, glucose homeostasis, and insulin resistance. Defects in PPARs have been linked to lipodystrophy, obesity, and insulin resistance as a result of the impairment of adipose tissue expandability and functionality. PPARs can act as lipid sensors, and when optimally activated, can rewire many of the metabolic pathways typically disrupted in obesity leading to an improvement of metabolic homeostasis. PPARs also contribute to the homeostasis of adipose tissue under challenging physiological circumstances, such as pregnancy and aging. Given their potential pathogenic role and their therapeutic potential, the benefits of PPARs activation should not only be considered relevant in the context of energy balance-associated pathologies and insulin resistance but also as potential relevant targets in the context of diabetic pregnancy and changes in body composition and metabolic stress associated with aging. Here, we review the rationale for the optimization of PPAR activation under these conditions.
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Affiliation(s)
- Patricia Corrales
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n. Alcorcón, 28922 Madrid, Spain.
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, University of Cambridge, Cambridge CB2 0QQ, UK.
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire CB10 1SA, UK.
| | - Gema Medina-Gómez
- Área de Bioquímica y Biología Molecular, Departamento de Ciencias Básicas de la Salud, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avda. de Atenas s/n. Alcorcón, 28922 Madrid, Spain.
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12
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Chung HS, Hwang SY, Choi JH, Lee HJ, Kim NH, Yoo HJ, Seo JA, Kim SG, Kim NH, Baik SH, Choi KM. Implications of circulating Meteorin-like (Metrnl) level in human subjects with type 2 diabetes. Diabetes Res Clin Pract 2018; 136:100-107. [PMID: 29199003 DOI: 10.1016/j.diabres.2017.11.031] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 11/06/2017] [Accepted: 11/28/2017] [Indexed: 12/25/2022]
Abstract
AIMS Meteorin-like (Metrnl) was recently identified as a novel adipomyokine induced by exercise and cold exposure. Metrnl improves glucose tolerance, increases systemic energy expenditure, induces white adipose browning, and promotes anti-inflammatory gene programs in obese/diabetic mice. However, the relationship of Metrnl with diabetes and cardiometabolic risk variables in humans has not been explored. METHODS In 800 subjects (400 patients with type 2 diabetes and 400 non-diabetes), Metrnl concentration was measured with an enzyme-linked immunosorbent assay, and the correlations of Metrnl level with anthropometric parameters, lifestyle factors, body composition values, and laboratory measurements were assessed. RESULTS Metrnl concentration was significantly higher in patients with diabetes than in those without diabetes [median (inter-quartile range); diabetes: 1219.9 (1020.6, 1535.6), non-diabetes: 1131.2 (993.1, 1313.6) pg/ml, P < .001]. After adjustment for age and sex, Metrnl level was significantly associated with fasting plasma glucose, blood pressure, lipid profile, and eGFR, but not with BMI or percent body fat. Multiple stepwise regression analysis exhibited that Metrnl level was independently associated with diabetes status (P < .001), eGFR (P < .001), and total cholesterol (P = .026) (R2 = 0.127). In multiple logistic regression analysis, the odds ratio for the risk of diabetes was 3.53 (95% confidence interval: 2.04-6.10) in the highest tertile of Metrnl compared to the lowest after adjustment for confounding factors. CONCLUSIONS This study is the first to demonstrate that Metrnl level is elevated in human subjects with type 2 diabetes and is inversely related to various cardiometabolic risk factors, including renal function.
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Affiliation(s)
- Hye Soo Chung
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Soon Young Hwang
- Department of Biostatistics, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Ju Hee Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Hyun Jung Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Nam Hoon Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Hye Jin Yoo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Ji-A Seo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sin Gon Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Nan Hee Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Sei Hyun Baik
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea
| | - Kyung Mook Choi
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Korea University, Seoul, Republic of Korea.
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13
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Lotta LA, Gulati P, Day FR, Payne F, Ongen H, van de Bunt M, Gaulton KJ, Eicher JD, Sharp SJ, Luan J, De Lucia Rolfe E, Stewart ID, Wheeler E, Willems SM, Adams C, Yaghootkar H, Forouhi NG, Khaw KT, Johnson AD, Semple RK, Frayling T, Perry JRB, Dermitzakis E, McCarthy MI, Barroso I, Wareham NJ, Savage DB, Langenberg C, O’Rahilly S, Scott RA. Integrative genomic analysis implicates limited peripheral adipose storage capacity in the pathogenesis of human insulin resistance. Nat Genet 2017; 49:17-26. [PMID: 27841877 PMCID: PMC5774584 DOI: 10.1038/ng.3714] [Citation(s) in RCA: 370] [Impact Index Per Article: 52.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/10/2016] [Indexed: 02/07/2023]
Abstract
Insulin resistance is a key mediator of obesity-related cardiometabolic disease, yet the mechanisms underlying this link remain obscure. Using an integrative genomic approach, we identify 53 genomic regions associated with insulin resistance phenotypes (higher fasting insulin levels adjusted for BMI, lower HDL cholesterol levels and higher triglyceride levels) and provide evidence that their link with higher cardiometabolic risk is underpinned by an association with lower adipose mass in peripheral compartments. Using these 53 loci, we show a polygenic contribution to familial partial lipodystrophy type 1, a severe form of insulin resistance, and highlight shared molecular mechanisms in common/mild and rare/severe insulin resistance. Population-level genetic analyses combined with experiments in cellular models implicate CCDC92, DNAH10 and L3MBTL3 as previously unrecognized molecules influencing adipocyte differentiation. Our findings support the notion that limited storage capacity of peripheral adipose tissue is an important etiological component in insulin-resistant cardiometabolic disease and highlight genes and mechanisms underpinning this link.
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Affiliation(s)
- Luca A. Lotta
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Pawan Gulati
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
| | - Felix R. Day
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Felicity Payne
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United
Kingdom
| | - Halit Ongen
- Department of Genetic Medicine and Development, University of Geneva
Medical School, Geneva, Switzerland
| | - Martijn van de Bunt
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University
of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford,
Oxford, United Kingdom
| | - Kyle J. Gaulton
- Department of Pediatrics, University of California San Diego, La
Jolla, USA
| | - John D. Eicher
- Population Sciences Branch, Division of Intramural Research,
National Heart, Lung and Blood Institute, Bethesda, USA
| | - Stephen J. Sharp
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Jian’an Luan
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | | | - Isobel D. Stewart
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Eleanor Wheeler
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United
Kingdom
| | - Sara M. Willems
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Claire Adams
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
| | - Hanieh Yaghootkar
- Genetics of Complex Traits, Institute of Biomedical and Clinical
Science, University of Exeter Medical School, Royal Devon and Exeter Hospital,
Exeter, United Kingdom
| | | | | | - Nita G. Forouhi
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Kay-Tee Khaw
- Department of Public Health and Primary Care, University of
Cambridge, Cambridge, United Kingdom
| | - Andrew D. Johnson
- Population Sciences Branch, Division of Intramural Research,
National Heart, Lung and Blood Institute, Bethesda, USA
| | - Robert K. Semple
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
| | - Timothy Frayling
- Genetics of Complex Traits, Institute of Biomedical and Clinical
Science, University of Exeter Medical School, Royal Devon and Exeter Hospital,
Exeter, United Kingdom
| | - John R. B. Perry
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Emmanouil Dermitzakis
- Department of Genetic Medicine and Development, University of Geneva
Medical School, Geneva, Switzerland
| | - Mark I. McCarthy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University
of Oxford, Oxford, United Kingdom
- Wellcome Trust Centre for Human Genetics, University of Oxford,
Oxford, United Kingdom
| | - Inês Barroso
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, United
Kingdom
| | | | - David B. Savage
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
| | - Claudia Langenberg
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
| | - Stephen O’Rahilly
- Metabolic Research Laboratories, Institute of Metabolic Science,
University of Cambridge, Cambridge, United Kingdom
| | - Robert A. Scott
- MRC Epidemiology Unit, University of Cambridge, Cambridge, United
Kingdom
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14
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Pap A, Cuaranta-Monroy I, Peloquin M, Nagy L. Is the Mouse a Good Model of Human PPARγ-Related Metabolic Diseases? Int J Mol Sci 2016; 17:E1236. [PMID: 27483259 DOI: 10.3390/ijms17081236] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 07/19/2016] [Accepted: 07/21/2016] [Indexed: 12/21/2022] Open
Abstract
With the increasing number of patients affected with metabolic diseases such as type 2 diabetes, obesity, atherosclerosis and insulin resistance, academic researchers and pharmaceutical companies are eager to better understand metabolic syndrome and develop new drugs for its treatment. Many studies have focused on the nuclear receptor peroxisome proliferator-activated receptor gamma (PPARγ), which plays a crucial role in adipogenesis and lipid metabolism. These studies have been able to connect this transcription factor to several human metabolic diseases. Due to obvious limitations concerning experimentation in humans, animal models—mainly mouse models—have been generated to investigate the role of PPARγ in different tissues. This review focuses on the metabolic features of human and mouse PPARγ-related diseases and the utility of the mouse as a model.
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15
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Stump M, Guo DF, Lu KT, Mukohda M, Liu X, Rahmouni K, Sigmund CD. Effect of selective expression of dominant-negative PPARγ in pro-opiomelanocortin neurons on the control of energy balance. Physiol Genomics 2016; 48:491-501. [PMID: 27199455 DOI: 10.1152/physiolgenomics.00032.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/06/2016] [Indexed: 01/01/2023] Open
Abstract
Peroxisome proliferator-activated receptor-γ (PPARγ), a master regulator of adipogenesis, was recently shown to affect energy homeostasis through its actions in the brain. Deletion of PPARγ in mouse brain, and specifically in the pro-opiomelanocortin (POMC) neurons, results in resistance to diet-induced obesity. To study the mechanisms by which PPARγ in POMC neurons controls energy balance, we constructed a Cre-recombinase-dependent conditionally activatable transgene expressing either wild-type (WT) or dominant-negative (P467L) PPARγ and the tdTomato reporter. Inducible expression of both forms of PPARγ was validated in cells in culture, in liver of mice infected with an adenovirus expressing Cre-recombinase (AdCre), and in the brain of mice expressing Cre-recombinase either in all neurons (NES(Cre)/PPARγ-P467L) or selectively in POMC neurons (POMC(Cre)/PPARγ-P467L). Whereas POMC(Cre)/PPARγ-P467L mice exhibited a normal pattern of weight gain when fed 60% high-fat diet, they exhibited increased weight gain and fat mass accumulation in response to a 10% fat isocaloric-matched control diet. POMC(Cre)/PPARγ-P467L mice were leptin sensitive on control diet but became leptin resistant when fed 60% high-fat diet. There was no difference in body weight between POMC(Cre)/PPARγ-WT mice and controls in response to 60% high-fat diet. However, POMC(Cre)/PPARγ-WT, but not POMC(Cre)/PPARγ-P467L, mice increased body weight in response to rosiglitazone, a PPARγ agonist. These observations support the concept that alterations in PPARγ-driven mechanisms in POMC neurons can play a role in the regulation of metabolic homeostasis under certain dietary conditions.
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Affiliation(s)
- Madeliene Stump
- Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Deng-Fu Guo
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Ko-Ting Lu
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Masashi Mukohda
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Xuebo Liu
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Kamal Rahmouni
- Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Curt D Sigmund
- Medical Scientist Training Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa; and UIHC Center for Hypertension Research, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa
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16
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Luo Y, Burrington CM, Graff EC, Zhang J, Judd RL, Suksaranjit P, Kaewpoowat Q, Davenport SK, O'Neill AM, Greene MW. Metabolic phenotype and adipose and liver features in a high-fat Western diet-induced mouse model of obesity-linked NAFLD. Am J Physiol Endocrinol Metab 2016; 310:E418-39. [PMID: 26670487 PMCID: PMC4796265 DOI: 10.1152/ajpendo.00319.2015] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 12/04/2015] [Indexed: 12/15/2022]
Abstract
nonalcoholic fatty liver disease (NAFLD), an obesity and insulin resistance associated clinical condition - ranges from simple steatosis to nonalcoholic steatohepatitis. To model the human condition, a high-fat Western diet that includes liquid sugar consumption has been used in mice. Even though liver pathophysiology has been well characterized in the model, little is known about the metabolic phenotype (e.g., energy expenditure, activity, or food intake). Furthermore, whether the consumption of liquid sugar exacerbates the development of glucose intolerance, insulin resistance, and adipose tissue dysfunction in the model is currently in question. In our study, a high-fat Western diet (HFWD) with liquid sugar [fructose and sucrose (F/S)] induced acute hyperphagia above that observed in HFWD-fed mice, yet without changes in energy expenditure. Liquid sugar (F/S) exacerbated HFWD-induced glucose intolerance and insulin resistance and impaired the storage capacity of epididymal white adipose tissue (eWAT). Hepatic TG, plasma alanine aminotransferase, and normalized liver weight were significantly increased only in HFWD+F/S-fed mice. HFWD+F/S also resulted in increased hepatic fibrosis and elevated collagen 1a2, collagen 3a1, and TGFβ gene expression. Furthermore, HWFD+F/S-fed mice developed more profound eWAT inflammation characterized by adipocyte hypertrophy, macrophage infiltration, a dramatic increase in crown-like structures, and upregulated proinflammatory gene expression. An early hypoxia response in the eWAT led to reduced vascularization and increased fibrosis gene expression in the HFWD+F/S-fed mice. Our results demonstrate that sugary water consumption induces acute hyperphagia, limits adipose tissue expansion, and exacerbates glucose intolerance and insulin resistance, which are associated with NAFLD progression.
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Affiliation(s)
- Yuwen Luo
- Department of Nutrition, Auburn University, Auburn, Alabama
| | | | - Emily C Graff
- College of Veterinary Medicine, Auburn University, Auburn, Alabama; and
| | - Jian Zhang
- Department of Nutrition, Auburn University, Auburn, Alabama
| | - Robert L Judd
- College of Veterinary Medicine, Auburn University, Auburn, Alabama; and Boshell Metabolic Diseases and Diabetes Program, Auburn University, Auburn, Alabama
| | - Promporn Suksaranjit
- Department of Internal Medicine, Bassett Medical Center, Cooperstown, New York, and
| | | | | | | | - Michael W Greene
- Department of Nutrition, Auburn University, Auburn, Alabama; Boshell Metabolic Diseases and Diabetes Program, Auburn University, Auburn, Alabama; Bassett Research Institute, Bassett Medical Center, Cooperstown, New York;
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17
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Hallenborg P, Petersen RK, Kouskoumvekaki I, Newman JW, Madsen L, Kristiansen K. The elusive endogenous adipogenic PPARγ agonists: Lining up the suspects. Prog Lipid Res 2016; 61:149-62. [DOI: 10.1016/j.plipres.2015.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/06/2015] [Accepted: 11/10/2015] [Indexed: 02/07/2023]
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18
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Li ZY, Song J, Zheng SL, Fan MB, Guan YF, Qu Y, Xu J, Wang P, Miao CY. Adipocyte Metrnl Antagonizes Insulin Resistance Through PPARγ Signaling. Diabetes 2015; 64:4011-22. [PMID: 26307585 DOI: 10.2337/db15-0274] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 08/04/2015] [Indexed: 11/13/2022]
Abstract
Adipokines play important roles in metabolic homeostasis and disease. We have recently identified a novel adipokine Metrnl, also known as Subfatin, for its high expression in subcutaneous fat. Here, we demonstrate a prodifferentiation action of Metrnl in white adipocytes. Adipocyte-specific knockout of Metrnl exacerbates insulin resistance induced by high-fat diet (HFD), whereas adipocyte-specific transgenic overexpression of Metrnl prevents insulin resistance induced by HFD or leptin deletion. Body weight and adipose content are not changed by adipocyte Metrnl. Consistently, no correlation is found between serum Metrnl level and BMI in humans. Metrnl promotes white adipocyte differentiation, expandability, and lipid metabolism and inhibits adipose inflammation to form functional fat, which contributes to its activity against insulin resistance. The insulin sensitization of Metrnl is blocked by PPARγ inhibitors or knockdown. However, Metrnl does not drive white adipose browning. Acute intravenous injection of recombinant Metrnl has no hypoglycemic effect, and 1-week intravenous administration of Metrnl is unable to rescue insulin resistance exacerbated by adipocyte Metrnl deficiency. Our results suggest adipocyte Metrnl controls insulin sensitivity at least via its local autocrine/paracrine action through the PPARγ pathway. Adipocyte Metrnl is an inherent insulin sensitizer and may become a therapeutic target for insulin resistance.
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Affiliation(s)
- Zhi-Yong Li
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Jie Song
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Si-Li Zheng
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Mao-Bing Fan
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Yun-Feng Guan
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Yi Qu
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Jian Xu
- Department of Laboratory Diagnosis, Changhai Hospital, Second Military Medical University, Shanghai, China
| | - Pei Wang
- Department of Pharmacology, Second Military Medical University, Shanghai, China
| | - Chao-Yu Miao
- Department of Pharmacology, Second Military Medical University, Shanghai, China
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19
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Ferrer-Lorente R, Bejar MT, Badimon L. Notch signaling pathway activation in normal and hyperglycemic rats differs in the stem cells of visceral and subcutaneous adipose tissue. Stem Cells Dev 2015; 23:3034-48. [PMID: 25035907 DOI: 10.1089/scd.2014.0070] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
The precise mechanisms underlying the differential function and cardiometabolic risk of white adipose tissue (WAT) remain unclear. Visceral adipose tissue (VWAT) and subcutaneous adipose tissue (SCWAT) have different metabolic functions that seem to be ascribed to their different intrinsic expansion capacities. Here we have hypothesized that the WAT characteristics are determined by the resident adipose-derived stem cells (ASCs) found in the different WAT depots. Therefore, our objective has been to investigate adipogenesis in anatomically distinct fat depots. ASCs from five different WAT depots were characterized in both healthy lean and diabetic obese rats, showing significant differences in expression of some of genes governing the stemness and the earlier adipogenic differentiation steps. Notch-target genes [Hes (hairy and enhancer of split) and Hey (hairy/enhancer of split related with YRPW motif) families] were upregulated in ASCs derived from visceral depots. Upon adipogenic differentiation, adipocyte cell markers were downregulated in ASCs from VWAT in comparison to ASCs from SCWAT, revealing a lower adipogenic capacity in ASCs of visceral origin than in those of SCWAT in accordance with the differential activation of Notch signaling. Notch upregulation by its activator phenethyl isothiocyanate attenuated the adipogenic differentiation of ASCs from SCWAT whereas Notch inhibition by N-[N-(3,5-difluorophenacetyl-L-alanyl)]-S-phenylglycine t-butyl ester (DAPT) increased the adipogenic differentiation of ASCs from visceral origin. In conclusion, the differential activation of Notch in ASCs is the origin of the different intrinsic WAT expansion capacities that contribute to the regional variations in WAT homeostasis and to its associated cardiometabolic risk.
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Affiliation(s)
- Raquel Ferrer-Lorente
- 1 Cardiovascular Research Center, CSIC-ICCC , Hospital de la Santa Creu i Sant Pau (UAB), Barcelona, Spain
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20
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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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21
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Teixeira TFS, Alves RDM, Moreira APB, Peluzio MDCG. Main characteristics of metabolically obese normal weight and metabolically healthy obese phenotypes. Nutr Rev 2015; 73:175-90. [PMID: 26024540 DOI: 10.1093/nutrit/nuu007] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In this review, the influence of fat depots on insulin resistance and the main characteristics of metabolically obese normal-weight and metabolically healthy obese phenotypes are discussed. Medline/PubMed and Science Direct were searched for articles related to the terms metabolically healthy obesity, metabolically obese normal weight, adipose tissue, and insulin resistance. Normal weight and obesity might be heterogeneous in regard to their effects. Fat distribution and lower insulin sensitivity are the main factors defining phenotypes within the same body mass index. Although these terms are interesting, controversies about them remain. Future studies exploring these phenotypes will help elucidate the roles of adiposity and/or insulin resistance in the development of metabolic alterations.
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Affiliation(s)
- Tatiana F S Teixeira
- TFS Teixeira, RDM Alves, APB Moreira, and MdCG Peluzio are with the Nutrition and Health Department, Federal University of Viçosa, Viçosa, MG, Brazil.
| | - Raquel D M Alves
- TFS Teixeira, RDM Alves, APB Moreira, and MdCG Peluzio are with the Nutrition and Health Department, Federal University of Viçosa, Viçosa, MG, Brazil
| | - Ana Paula B Moreira
- TFS Teixeira, RDM Alves, APB Moreira, and MdCG Peluzio are with the Nutrition and Health Department, Federal University of Viçosa, Viçosa, MG, Brazil
| | - Maria do Carmo G Peluzio
- TFS Teixeira, RDM Alves, APB Moreira, and MdCG Peluzio are with the Nutrition and Health Department, Federal University of Viçosa, Viçosa, MG, Brazil
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Zhou L, Park SY, Xu L, Xia X, Ye J, Su L, Jeong KH, Hur JH, Oh H, Tamori Y, Zingaretti CM, Cinti S, Argente J, Yu M, Wu L, Ju S, Guan F, Yang H, Choi CS, Savage DB, Li P. Insulin resistance and white adipose tissue inflammation are uncoupled in energetically challenged Fsp27-deficient mice. Nat Commun 2015; 6:5949. [PMID: 25565658 DOI: 10.1038/ncomms6949] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2014] [Accepted: 11/18/2014] [Indexed: 12/19/2022] Open
Abstract
Fsp27 is a lipid droplet-associated protein almost exclusively expressed in adipocytes where it facilitates unilocular lipid droplet formation. In mice, Fsp27 deficiency is associated with increased basal lipolysis, ‘browning’ of white fat and a healthy metabolic profile, whereas a patient with congenital CIDEC deficiency manifested an adverse lipodystrophic phenotype. Here we reconcile these data by showing that exposing Fsp27-null mice to a substantial energetic stress by crossing them with ob/ob mice or BATless mice, or feeding them a high-fat diet, results in hepatic steatosis and insulin resistance. We also observe a striking reduction in adipose inflammation and increase in adiponectin levels in all three models. This appears to reflect reduced activation of the inflammasome and less adipocyte death. These findings highlight the importance of Fsp27 in facilitating optimal energy storage in adipocytes and represent a rare example where adipose inflammation and hepatic insulin resistance are disassociated. Fsp27 mediates ‘fusion’ of lipid droplets in mouse adipose tissue. Here, the authors investigate the physiological consequences of loss of Fsp27 in three different mouse models of ‘energetic overload’, and observe hepatic steatosis and insulin resistance but reduced adipose tissue inflammation.
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McMorrow AM, Connaughton RM, Lithander FE, Roche HM. Adipose tissue dysregulation and metabolic consequences in childhood and adolescent obesity: potential impact of dietary fat quality. Proc Nutr Soc 2015; 74:67-82. [PMID: 25497038 DOI: 10.1017/S002966511400158X] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Evidence suggests that at a population level, childhood and adolescent obesity increase the long-term risk of chronic diseases such as type 2 diabetes and CVD. At an individual level, however, the metabolic consequences of obesity in youth vary immensely. Despite comparable BMI, some adolescents develop impaired glucose tolerance while others maintain normal glucose homeostasis. It has been proposed that the variation in the capacity to store lipid in the subcutaneous adipose tissue (SAT) may partially discriminate metabolically healthy from unhealthy obesity. In positive energy balance, a decreased capacity to expand SAT may drive lipid accumulation to visceral adipose tissue, liver and skeletal muscle. This state of lipotoxicity is associated with chronic low-grade inflammation, insulin resistance and dyslipidaemia. The present review examines the differential adipose tissue development and function in children and adolescents who exhibit metabolic dysregulation compared with those who are protected. Additionally, the role of manipulating dietary fat quality to potentially prevent and treat metabolic dysfunction in obesity will be discussed. The findings of the present review highlight the need for further randomised controlled trials to establish the effect of dietary n-3 PUFA on the metabolic phenotype of obese children and adolescents. Furthermore, using a personalised nutrition approach to target interventions to those at risk of, or those with established metabolic dysregulation may optimise the efficacy of modifying dietary fat quality.
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Carrillo-Sepulveda MA, Keen HL, Davis DR, Grobe JL, Sigmund CD. Role of vascular smooth muscle PPARγ in regulating AT1 receptor signaling and angiotensin II-dependent hypertension. PLoS One 2014; 9:e103786. [PMID: 25122005 PMCID: PMC4133177 DOI: 10.1371/journal.pone.0103786] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Accepted: 07/04/2014] [Indexed: 12/04/2022] Open
Abstract
Peroxisome proliferator activated receptor γ (PPARγ) has been reported to play a protective role in the vasculature; however, the underlying mechanisms involved are not entirely known. We previously showed that vascular smooth muscle-specific overexpression of a dominant negative human PPARγ mutation in mice (S-P467L) leads to enhanced myogenic tone and increased angiotensin-II-dependent vasoconstriction. S-P467L mice also exhibit increased arterial blood pressure. Here we tested the hypotheses that a) mesenteric smooth muscle cells isolated from S-P467L mice exhibit enhanced angiotensin-II AT1 receptor signaling, and b) the increased arterial pressure of S-P467L mice is angiotensin-II AT1 receptor dependent. Phosphorylation of mitogen-activated protein/extracellular signal-regulated kinase (ERK1/2) was robustly increased in mesenteric artery smooth muscle cell cultures from S-P467L in response to angiotensin-II. The increase in ERK1/2 activation by angiotensin-II was blocked by losartan, a blocker of AT1 receptors. Angiotensin-II-induced ERK1/2 activation was also blocked by Tempol, a scavenger of reactive oxygen species, and correlated with increased Nox4 protein expression. To investigate whether endogenous renin-angiotensin system activity contributes to the elevated arterial pressure in S-P467L, non-transgenic and S-P467L mice were treated with the AT1 receptor blocker, losartan (30 mg/kg per day), for 14-days and arterial pressure was assessed by radiotelemetry. At baseline S-P467L mice showed a significant increase of systolic arterial pressure (142.0±10.2 vs 129.1±3.0 mmHg, p<0.05). Treatment with losartan lowered systolic arterial pressure in S-P467L (132.2±6.9 mmHg) to a level similar to untreated non-transgenic mice. Losartan also lowered arterial pressure in non-transgenic (113.0±3.9 mmHg) mice, such that there was no difference in the losartan-induced depressor response between groups (−13.53±1.39 in S-P467L vs −16.16±3.14 mmHg in non-transgenic). Our results suggest that interference with PPARγ in smooth muscle: a) causes enhanced angiotensin-II AT1 receptor-mediated ERK1/2 activation in resistance vessels, b) and may elevate arterial pressure through both angiotensin-II AT1 receptor-dependent and -independent mechanisms.
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MESH Headings
- Angiotensin II/metabolism
- Animals
- Arterial Pressure/drug effects
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Humans
- Hypertension/drug therapy
- Hypertension/metabolism
- Losartan/pharmacology
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic/metabolism
- Mitogen-Activated Protein Kinase 3/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- PPAR gamma/metabolism
- Reactive Oxygen Species/metabolism
- Receptor, Angiotensin, Type 1/metabolism
- Renin-Angiotensin System/drug effects
- Signal Transduction/drug effects
- Vasoconstriction/drug effects
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Affiliation(s)
- Maria Alicia Carrillo-Sepulveda
- Department of Pharmacology and Roy J. and A. Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Henry L. Keen
- Department of Pharmacology and Roy J. and A. Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Deborah R. Davis
- Department of Pharmacology and Roy J. and A. Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Justin L. Grobe
- Department of Pharmacology and Roy J. and A. Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
| | - Curt D. Sigmund
- Department of Pharmacology and Roy J. and A. Lucille Carver College of Medicine, University of Iowa, Iowa City, Iowa, United States of America
- * E-mail:
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25
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26
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Affiliation(s)
- Frederick W Quelle
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Xue P, Hou Y, Chen Y, Yang B, Fu J, Zheng H, Yarborough K, Woods CG, Liu D, Yamamoto M, Zhang Q, Andersen ME, Pi J. Adipose deficiency of Nrf2 in ob/ob mice results in severe metabolic syndrome. Diabetes 2013; 62:845-54. [PMID: 23238296 PMCID: PMC3581189 DOI: 10.2337/db12-0584] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that functions as a master regulator of the cellular adaptive response to oxidative stress. Our previous studies showed that Nrf2 plays a critical role in adipogenesis by regulating expression of CCAAT/enhancer-binding protein β and peroxisome proliferator-activated receptor γ. To determine the role of Nrf2 in the development of obesity and associated metabolic disorders, the incidence of metabolic syndrome was assessed in whole-body or adipocyte-specific Nrf2-knockout mice on a leptin-deficient ob/ob background, a model with an extremely positive energy balance. On the ob/ob background, ablation of Nrf2, globally or specifically in adipocytes, led to reduced white adipose tissue (WAT) mass, but resulted in an even more severe metabolic syndrome with aggravated insulin resistance, hyperglycemia, and hypertriglyceridemia. Compared with wild-type mice, WAT of ob/ob mice expressed substantially higher levels of many genes related to antioxidant response, inflammation, adipogenesis, lipogenesis, glucose uptake, and lipid transport. Absence of Nrf2 in WAT resulted in reduced expression of most of these factors at mRNA or protein levels. Our findings support a novel role for Nrf2 in regulating adipose development and function, by which Nrf2 controls the capacity of WAT expansion and insulin sensitivity and maintains glucose and lipid homeostasis.
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Affiliation(s)
- Peng Xue
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Yongyong Hou
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Yanyan Chen
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
- School of First Clinical Sciences, China Medical University, Shenyang, China
| | - Bei Yang
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
- College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Jingqi Fu
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Hongzhi Zheng
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
- School of First Clinical Sciences, China Medical University, Shenyang, China
| | - Kathy Yarborough
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Courtney G. Woods
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Dianxin Liu
- Metabolic Signaling and Disease Program, Sanford-Burnham Medical Research Institute, Orlando, Florida
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Qiang Zhang
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Melvin E. Andersen
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
| | - Jingbo Pi
- Institute for Chemical Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, North Carolina
- Corresponding author: Jingbo Pi,
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Duszka K, Bogner-Strauss JG, Hackl H, Rieder D, Neuhold C, Prokesch A, Trajanoski Z, Krogsdam AM. Nr4a1 is required for fasting-induced down-regulation of Pparγ2 in white adipose tissue. Mol Endocrinol 2012; 27:135-49. [PMID: 23250487 DOI: 10.1210/me.2012-1248] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Expression of the nuclear receptor gene, Nur77 (Nr4a1), is induced in white adipose tissue (WAT) in response to β-adrenergic stimulation and fasting. Recently, Nur77 has been shown to play a gene regulatory role in the fasting response of several other major metabolic tissues. Here we investigated the effects of Nur77 on the WAT transcriptome after fasting. For this purpose, we performed gene expression profiling of WAT from wild-type and Nur77(-/-) mice submitted to prolonged fasting. Results revealed Nur77-dependent changes in expression profiles of 135 transcripts, many involved in insulin signaling, lipid and fatty acid metabolism, and glucose metabolism. Network analysis identified the deregulated genes Pparγ2 and Nur77 as central hubs and closely connected in the network, indicating overlapping biological function. We further assayed the expression level of Pparγ2 in a bigger cohort of fasted mice and found a significant Nur77-dependent down-regulation of Pparγ2 in the wild-type mice (P = 0.021, n = 10). Consistently, the expression of several known Pparγ2 targets, found among the Nur77-regulated genes (i.e. G0s2, Grp81, Fabp4, and Adipoq), were up-regulated in WAT of fasted Nur77(-/-) mice. Finally, we show with chromatin immunoprecipitation and luciferase assays that the Pparγ2 promoter is a direct target of Nurr-related 77-kDa protein (Nur77)-dependent repressive regulation and that the N-terminal domain of Nur77 is required for this regulation. In conclusion, we present data implicating Nur77 as a mediator of fasting-induced Pparγ2 regulation in WAT.
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Affiliation(s)
- Kalina Duszka
- Division of Bioinformatics, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria
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Ketsawatsomkron P, Lorca RA, Keen HL, Weatherford ET, Liu X, Pelham CJ, Grobe JL, Faraci FM, England SK, Sigmund CD. PPARγ regulates resistance vessel tone through a mechanism involving RGS5-mediated control of protein kinase C and BKCa channel activity. Circ Res 2012; 111:1446-58. [PMID: 22962432 DOI: 10.1161/circresaha.112.271577] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Activation of peroxisome proliferator-activated receptor-γ (PPARγ) by thiazolidinediones lowers blood pressure, whereas PPARγ mutations cause hypertension. Previous studies suggest these effects may be mediated through the vasculature, but the underlying mechanisms remain unclear. OBJECTIVE To identify PPARγ mechanisms and transcriptional targets in vascular smooth muscle and their role in regulating resistance artery tone. METHODS AND RESULTS We studied mesenteric artery (MA) from transgenic mice expressing dominant-negative (DN) mutant PPARγ driven by a smooth muscle cell-specific promoter. MA from transgenic mice exhibited a robust increase in myogenic tone. Patch clamp analysis revealed a reduced large conductance Ca(2+)-activated K(+) (BKCa) current in freshly dissociated smooth muscle cell from transgenic MA. Inhibition of protein kinase C corrected both enhanced myogenic constriction and impaired the large conductance Ca(2+)-activated K(+) channel function. Gene expression profiling revealed a marked loss of the regulator of G protein signaling 5 (RGS5) mRNA in transgenic MA, which was accompanied by a substantial increase in angiotensin II-induced constriction in MA. Small interfering RNA targeting RGS5 caused augmented myogenic tone in intact mesenteric arteries and increased activation of protein kinase C in smooth muscle cell cultures. PPARγ and PPARδ each bind to a PPAR response element close to the RGS5 promoter. RGS5 expression in nontransgenic MA was induced after activation of either PPARγ or PPARδ, an effect that was markedly blunted by DN PPARγ. CONCLUSIONS We conclude that RGS5 in smooth muscle is a PPARγ and PPARδ target, which when activated blunts angiotensin II-mediated activation of protein kinase C, and preserves the large conductance Ca(2+)-activated K(+) channel activity, thus providing tight control of myogenic tone in the microcirculation.
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Affiliation(s)
- Pimonrat Ketsawatsomkron
- Department of Pharmacology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Morine MJ, Toomey S, McGillicuddy FC, Reynolds CM, Power KA, Browne JA, Loscher C, Mills KHG, Roche HM. Network analysis of adipose tissue gene expression highlights altered metabolic and regulatory transcriptomic activity in high-fat-diet-fed IL-1RI knockout mice. J Nutr Biochem 2012; 24:788-95. [PMID: 22841542 DOI: 10.1016/j.jnutbio.2012.04.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 04/22/2012] [Accepted: 04/26/2012] [Indexed: 11/27/2022]
Abstract
A subacute inflammatory phenotype is implicated in the pathology of insulin resistance (IR) and type 2 diabetes mellitus. Interleukin (IL)-1α and IL-1β are produced by innate immune cells, including macrophages, and mediate their inflammatory response through the IL-1 type I receptor (IL-IRI). This study sought to understand the transcriptomic signature of adipose tissue in obese IL-1RI(-/-) mice. Following dietary intervention, markers of insulin sensitivity and inflammation in adipose tissue were determined, and gene expression was assessed with microarrays. IL-1RI(-/-) mice fed a high-fat diet (HFD) had significantly lower plasma inflammatory cytokine concentrations than wild-type mice. Metabolic network analysis of transcriptomic effects identified up-regulation and co-expression of genes involved in lipolysis, lipogenesis and tricarboxylic acid (TCA) cycle. Further assessment of gene expression in a network of protein interactions related to innate immunity highlighted Stat3 as a potential transcriptional regulator of IL-1 signalling. The complex, downstream effects of IL-1 signalling through the IL-1RI receptor remain poorly defined. Using network-based analyses of transcriptomic signatures in IL-1RI(-/-) mice, we have identified expression changes in genes involved in lipid cycling and TCA cycle, which may be more broadly indicative of a restoration of mitochondrial function in the context of HFD. Our results also highlight a potential role for Stat3 in linking IL-1 signalling to adipogenesis and IR.
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Affiliation(s)
- Melissa J Morine
- Nutrigenomics Research Group, UCD Conway Institute, University College Dublin, Dublin 4, Ireland
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31
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Virtue S, Masoodi M, Velagapudi V, Tan CY, Dale M, Suorti T, Slawik M, Blount M, Burling K, Campbell M, Eguchi N, Medina-Gomez G, Sethi JK, Orešič M, Urade Y, Griffin JL, Vidal-Puig A. Lipocalin prostaglandin D synthase and PPARγ2 coordinate to regulate carbohydrate and lipid metabolism in vivo. PLoS One 2012; 7:e39512. [PMID: 22792179 PMCID: PMC3390315 DOI: 10.1371/journal.pone.0039512] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Accepted: 05/22/2012] [Indexed: 12/15/2022] Open
Abstract
Mice lacking Peroxisome Proliferator-Activated Receptor γ2 (PPARγ2) have unexpectedly normal glucose tolerance and mild insulin resistance. Mice lacking PPARγ2 were found to have elevated levels of Lipocalin prostaglandin D synthase (L-PGDS) expression in BAT and subcutaneous white adipose tissue (WAT). To determine if induction of L-PGDS was compensating for a lack of PPARγ2, we crossed L-PGDS KO mice to PPARγ2 KO mice to generate Double Knock Out mice (DKO). Using DKO mice we demonstrated a requirement of L-PGDS for maintenance of subcutaneous WAT (scWAT) function. In scWAT, DKO mice had reduced expression of thermogenic genes, the de novo lipogenic program and the lipases ATGL and HSL. Despite the reduction in markers of lipolysis in scWAT, DKO mice had a normal metabolic rate and elevated serum FFA levels compared to L-PGDS KO alone. Analysis of intra-abdominal white adipose tissue (epididymal WAT) showed elevated expression of mRNA and protein markers of lipolysis in DKO mice, suggesting that DKO mice may become more reliant on intra-abdominal WAT to supply lipid for oxidation. This switch in depot utilisation from subcutaneous to epididymal white adipose tissue was associated with a worsening of whole organism metabolic function, with DKO mice being glucose intolerant, and having elevated serum triglyceride levels compared to any other genotype. Overall, L-PGDS and PPARγ2 coordinate to regulate carbohydrate and lipid metabolism.
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Affiliation(s)
- Sam Virtue
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Mojgan Masoodi
- Elsie Widdowson Laboratory, Medical Research Council Human Nutrition Research, Cambridge, United Kingdom
| | | | - Chong Yew Tan
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Martin Dale
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Tapani Suorti
- VTT Technical Research Centre of Finland, Espoo, Finland
| | - Marc Slawik
- Department of Medicine Innenstadt, Endocrinology/Diabetes University Hospital, Munich, Germany
| | - Margaret Blount
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Keith Burling
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Mark Campbell
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | | | - Gema Medina-Gomez
- Departamento de Bioquímica, Fisiología y Genética Molecular, Universidad Rey Juan Carlos, Madrid, Spain
| | - Jaswinder K. Sethi
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
| | - Matej Orešič
- VTT Technical Research Centre of Finland, Espoo, Finland
| | | | - Julian L. Griffin
- Department of Biochemistry, Medical Research Council Human Nutrition Research, Cambridge, United Kingdom
| | - Antonio Vidal-Puig
- University of Cambridge Metabolic Research Laboratories, Institute of Metabolic Science, Cambridge, United Kingdom
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Pendse AA, Johnson LA, Kim HS, McNair M, Nipp CT, Wilhelm C, Maeda N. Pro- and antiatherogenic effects of a dominant-negative P465L mutation of peroxisome proliferator-activated receptor-γ in apolipoprotein E-Null mice. Arterioscler Thromb Vasc Biol 2012; 32:1436-44. [PMID: 22539598 DOI: 10.1161/atvbaha.112.248682] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The dominant-negative mutation, P467L, in peroxisome proliferator-activated receptor-γ (PPARγ) affects adipose tissue distribution, insulin sensitivity, and blood pressure in heterozygous humans. We hypothesized that the equivalent mutation, PPARγ-P465L, in mice will worsen atherosclerosis. METHODS AND RESULTS Apolipoprotein E-null mice with and without PPARγ-P465L mutation were bred in 129S6 inbred genetic background. Mild hypertension and lipodystrophy of PPARγ-P465L persisted in the apolipoprotein E-null background. Glucose homeostasis was normal, but plasma adiponectin was significantly lower and resistin was higher in PPARγ-P465L mice. Plasma cholesterol and lipoprotein distribution were not different, but plasma triglycerides tended to be reduced. Surprisingly, there were no overall changes in the atherosclerotic plaque size or composition. PPARγ-P465L macrophages had a small decrease in CD36 mRNA and a small yet significant reduction in very-low-density lipoprotein uptake in culture. In unloaded apolipoprotein E-null macrophages with PPARγ-P465L, cholesterol uptake was reduced whereas apolipoprotein AI-mediated efflux was increased. However, when cells were cholesterol loaded in the presence of acetylated low-density lipoprotein, no genotype difference in uptake or efflux was apparent. A reduction of vascular cell adhesion molecule-1 expression in aorta suggests a relatively antiatherogenic vascular environment in mice with PPARγ-P465L. CONCLUSIONS Small, competing pro- and antiatherogenic effects of PPARγ-P465L mutation result in unchanged plaque development in apolipoprotein E-deficient mice.
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Affiliation(s)
- Avani A Pendse
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, 710 Brinkhous-Bullitt Bldg, Chapel Hill, NC 27599-7525, USA
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Floyd ZE, Stephens JM. Controlling a master switch of adipocyte development and insulin sensitivity: covalent modifications of PPARγ. Biochim Biophys Acta Mol Basis Dis. 2012;1822:1090-1095. [PMID: 22504298 DOI: 10.1016/j.bbadis.2012.03.014] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 03/26/2012] [Accepted: 03/27/2012] [Indexed: 12/14/2022]
Abstract
Adipocytes are highly specialized cells that play a central role in lipid homeostasis and the maintenance of energy balance. Obesity, an excessive accumulation of adipose tissue, is a major risk factor for the development of Type 2 diabetes mellitus (T2DM), cardiovascular disease, and hypertension. A variety of studies suggest that obesity and T2DM can be linked to a breakdown in the regulatory mechanisms that control the expression and transcriptional activity of PPARγ. PPARγ is a nuclear hormone receptor that functions as a master switch in controlling adipocyte differentiation and development. Also important in controlling glucose homeostasis and insulin sensitivity, PPARγ is a ligand-dependent transcription factor that is the functional receptor for the anti-diabetic thiazolidinediones (TZDs). In the last fifteen years, a variety of covalent modifications of PPARγ activity have been identified and studied. These covalent modifications include phosphorylation, ubiquitylation, O-GlcNAcylation and SUMOylation. Covalent modifications of PPARγ represent key regulatory mechanisms that control both PPARγ protein stability and transcriptional activity. A variety of PPARγ transgenic models, including mice heterozygous for PPARγ, have demonstrated the importance of PPARγ expression in glucose homeostasis and insulin resistance. In the following review, we have highlighted the regulation of PPARγ by covalent modifications, the interplay between these interactions and how these post-translational modifications impact metabolic disease states.
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Rodriguez-Cuenca S, Carobbio S, Velagapudi VR, Barbarroja N, Moreno-Navarrete JM, Tinahones FJ, Fernandez-Real JM, Orešič M, Vidal-Puig A. Peroxisome proliferator-activated receptor γ-dependent regulation of lipolytic nodes and metabolic flexibility. Mol Cell Biol 2012; 32:1555-65. [PMID: 22310664 PMCID: PMC3318581 DOI: 10.1128/mcb.06154-11] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 01/28/2012] [Indexed: 12/15/2022] Open
Abstract
Optimal lipid storage and mobilization are essential for efficient adipose tissue. Nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) regulates adipocyte differentiation and lipid deposition, but its role in lipolysis and dysregulation in obesity is not well defined. This investigation aimed to understand the molecular impact of dysfunctional PPARγ on the lipolytic axis and to explore whether these defects are also confirmed in common forms of human obesity. For this purpose, we used the P465L PPARγ mouse as a model of dysfunctional PPARγ that recapitulates the human pparγ mutation (P467L). We demonstrated that defective PPARγ impairs catecholamine-induced lipolysis. This abnormal lipolytic response is exacerbated by a state of positive energy balance in leptin-deficient ob/ob mice. We identified the protein kinase A (PKA) network as a PPARγ-dependent regulatory node of the lipolytic response. Specifically, defective PPARγ is associated with decreased basal expression of prkaca (PKAcatα) and d-akap1, the lipase genes Pnplaz (ATGL) and Lipe (HSL), and lipid droplet protein genes fsp27 and adrp in vivo and in vitro. Our data indicate that PPARγ is required for activation of the lipolytic regulatory network, dysregulation of which is an important feature of obesity-induced insulin resistance in humans.
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Affiliation(s)
- Sergio Rodriguez-Cuenca
- Department of Clinical Biochemistry, Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Stefania Carobbio
- Department of Clinical Biochemistry, Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | | | - Nuria Barbarroja
- Department of Clinical Biochemistry, Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
- Hospital Virgen de la Victoria, CIBERobn Fisiopatología de la Obesidad y Nutrición, Malaga, Spain
| | - Jose Maria Moreno-Navarrete
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomédica de Girona, CIBERobn Fisiopatología de la Obesidad y Nutrición, Girona, Spain
| | - Francisco Jose Tinahones
- Hospital Virgen de la Victoria, CIBERobn Fisiopatología de la Obesidad y Nutrición, Malaga, Spain
| | - Jose Manuel Fernandez-Real
- Department of Diabetes, Endocrinology and Nutrition, Institut d'Investigació Biomédica de Girona, CIBERobn Fisiopatología de la Obesidad y Nutrición, Girona, Spain
| | - Matej Orešič
- VTT Technical Research Centre of Finland, Espoo, Finland
| | - Antonio Vidal-Puig
- Department of Clinical Biochemistry, Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
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Affiliation(s)
- Andrew Lansdown
- Centre for Endocrine and Diabetes Sciences, School of Medicine, Cardiff University, Heath Park, Cardiff, South Glamorgan, UK
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Passaro A, Dalla Nora E, Marcello C, Di Vece F, Morieri ML, Sanz JM, Bosi C, Fellin R, Zuliani G. PPARγ Pro12Ala and ACE ID polymorphisms are associated with BMI and fat distribution, but not metabolic syndrome. Cardiovasc Diabetol 2011; 10:112. [PMID: 22168210 PMCID: PMC3295652 DOI: 10.1186/1475-2840-10-112] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 12/14/2011] [Indexed: 12/04/2022] Open
Abstract
Background Metabolic Syndrome (MetS) results from the combined effect of environmental and genetic factors. We investigated the possible association of peroxisome proliferator-activated receptor-γ2 (PPARγ2) Pro12Ala and Angiotensin Converting Enzyme (ACE) I/D polymorphisms with MetS and interaction between these genetic variants. Methods Three hundred sixty four unrelated Caucasian subjects were enrolled. Waist circumference, blood pressure, and body mass index (BMI) were recorded. Body composition was estimated by impedance analysis; MetS was diagnosed by the NCEP-ATPIII criteria. A fasting blood sample was obtained for glucose, insulin, lipid profile determination, and DNA isolation for genotyping. Results The prevalence of MetS did not differ across PPARγ2 or ACE polymorphisms. Carriers of PPARγ2 Ala allele had higher BMI and fat-mass but lower systolic blood pressure compared with Pro/Pro homozygotes. A significant PPARγ2 gene-gender interaction was observed in the modulation of BMI, fat mass, and blood pressure, with significant associations found in women only. A PPARγ2-ACE risk genotype combination for BMI and fat mass was found, with ACE DD/PPARγ2 Ala subjects having a higher BMI (p = 0.002) and Fat Mass (p = 0.002). Pro12Ala was independently associated with waist circumference independent of BMI and gender. Conclusions Carriers of PPARγ2 Ala allele had higher BMI and fat-mass but not a worse metabolic profile, possibly because of a more favorable adipose tissue distribution. A gene interaction exists between Pro12Ala and ACE I/D on BMI and fat mass. Further studies are needed to assess the contribution of Pro12Ala polymorphism in adiposity distribution.
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Affiliation(s)
- Angela Passaro
- Department of Clinical and Experimental Medicine, Section of Internal Medicine, Gerontology and Clinical Nutrition, University of Ferrara, Ferrara, Italy.
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Gurung IS, Medina-Gomez G, Kis A, Baker M, Velagapudi V, Neogi SG, Campbell M, Rodriguez-Cuenca S, Lelliott C, McFarlane I, Oresic M, Grace AA, Vidal-Puig A, Huang CLH. Deletion of the metabolic transcriptional coactivator PGC1β induces cardiac arrhythmia. Cardiovasc Res 2011; 92:29-38. [PMID: 21632884 PMCID: PMC3172981 DOI: 10.1093/cvr/cvr155] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/17/2011] [Accepted: 05/26/2011] [Indexed: 01/23/2023] Open
Abstract
AIMS Peroxisome proliferator-activated receptor-γ coactivators PGC1α and PGC1β modulate mitochondrial biogenesis and energy homeostasis. The function of these transcriptional coactivators is impaired in obesity, insulin resistance, and type 2 diabetes. We searched for transcriptomic, lipidomic, and electrophysiological alterations in PGC1β(-/-) hearts potentially associated with increased arrhythmic risk in metabolic diseases. METHODS AND RESULTS Microarray analysis in mouse PGC1β(-/-) hearts confirmed down-regulation of genes related to oxidative phosphorylation and the electron transport chain and up-regulation of hypertrophy- and hypoxia-related genes. Lipidomic analysis showed increased levels of the pro-arrhythmic and pro-inflammatory lipid, lysophosphatidylcholine. PGC1β(-/-) mouse electrocardiograms showed irregular heartbeats and an increased incidence of polymorphic ventricular tachycardia following isoprenaline infusion. Langendorff-perfused PGC1β(-/-) hearts showed action potential alternans, early after-depolarizations, and ventricular tachycardia. PGC1β(-/-) ventricular myocytes showed oscillatory resting potentials, action potentials with early and delayed after-depolarizations, and burst firing during sustained current injection. They showed abnormal diastolic Ca(2+) transients, whose amplitude and frequency were increased by isoprenaline, and Ca(2+) currents with negatively shifted inactivation characteristics, with increased window currents despite unaltered levels of CACNA1C RNA transcripts. Inwardly and outward rectifying K(+) currents were all increased. Quantitiative RT-PCR demonstrated increased SCN5A, KCNA5, RYR2, and Ca(2+)-calmodulin dependent protein kinase II expression. CONCLUSION PGC1β(-/-) hearts showed a lysophospholipid-induced cardiac lipotoxicity and impaired bioenergetics accompanied by an ion channel remodelling and altered Ca(2+) homeostasis, converging to produce a ventricular arrhythmic phenotype particularly during adrenergic stress. This could contribute to the increased cardiac mortality associated with both metabolic and cardiac disease attributable to lysophospholipid accumulation.
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Affiliation(s)
- Iman S. Gurung
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
| | - Gema Medina-Gomez
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Adrienn Kis
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Michael Baker
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
| | - Vidya Velagapudi
- VTT Technical Research Centre of Finland, Tietotie 2, PO Box 1000, Espo,Finland
| | - Sudeshna Guha Neogi
- Genomics CoreLab, NIHR-Cambridge Biomedical Research Centre, University of Cambridge, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Mark Campbell
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Sergio Rodriguez-Cuenca
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Christopher Lelliott
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Ian McFarlane
- Genomics CoreLab, NIHR-Cambridge Biomedical Research Centre, University of Cambridge, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, UK
| | - Matej Oresic
- VTT Technical Research Centre of Finland, Tietotie 2, PO Box 1000, Espo,Finland
| | - Andrew A. Grace
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, University of Cambridge, Level 4, Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Christopher L.-H. Huang
- Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge CB2 3EG, UK
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, UK
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Götz AA, Vidal-Puig A, Rödel HG, de Angelis MH, Stoeger T. Carbon-nanoparticle-triggered acute lung inflammation and its resolution are not altered in PPARγ-defective (P465L) mice. Part Fibre Toxicol 2011; 8:28. [PMID: 21933390 PMCID: PMC3197489 DOI: 10.1186/1743-8977-8-28] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 09/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The alveolar macrophage (AM) - first line of innate immune defence against pathogens and environmental irritants - constitutively expresses peroxisome-proliferator activated receptor γ (PPARγ). PPARγ ligand-induced activation keeps the AM quiescent, and thereby contributes to combat invaders and resolve inflammation by augmenting the phagocytosis of apoptotic neutrophils and inhibiting an excessive expression of inflammatory genes. Because of these presumed anti-inflammatory functions of PPARγ we tested the hypothesis, whether reduced functional receptor availability in mutant mice resulted in increased cellular and molecular inflammatory response during acute inflammation and/or in an impairment of its resolution. METHODS To address this hypothesis we examined the effects of a carbon-nanoparticle (CNP) lung challenge, as surrogate for non-infectious environmental irritants, in a murine model carrying a dominant-negative point mutation in the ligand-binding domain of PPARγ (P465L/wt). Animals were instilled intratracheally with Printex 90 CNPs and bronchoalveolar lavage (BAL) was gained 24 h or 72 h after instillation to investigate its cellular and protein composition. RESULTS Higher BAL cell numbers - due to higher macrophage counts - were found in mutants irrespective of treatment. Neutrophil numbers in contrast were slightly lower in mutants. Intratracheal CNP instillation resulted in a profound recruitment of inflammatory neutrophils into the alveolus, but genotype related differences at acute inflammation (24 h) and resolution (72 h) were not observed. There were no signs for increased alveolar-capillary membrane damage or necrotic cell death in mutants as determined by BAL protein and lactate-dehydrogenase content. Pro-inflammatory macrophage-derived cytokine osteopontin was higher, but galectin-3 lower in female mutants. CXCL5 and lipocalin-2 markers, attributed to epithelial cell stimulation did not differ. CONCLUSIONS Despite general genotype-related differences, we had to reject our hypothesis of an increased CNP induced lung inflammation and an impairment of its resolution in PPARγ defective mice. Although earlier studies showed ligand-induced activation of nuclear receptor PPARγ to promote resolution of lung inflammation, its reduced activity did not provide signs of resolution impairment in the settings investigated here.
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Affiliation(s)
- Alexander A Götz
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg/Munich, D-85764, Germany
| | - Antonio Vidal-Puig
- Metabolic Research Laboratories, Level 4, Institute of Metabolic Science, Box 289, NIHR Cambridge Biomedical Research Centre Addenbrooke's Hospital, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Heiko G Rödel
- Laboratory of Experimental and Comparative Ethology, University of Paris 13, F-93430, Villetaneuse, France
| | - Martin Hrabé de Angelis
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg/Munich, D-85764, Germany
| | - Tobias Stoeger
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg/Munich, D-85764, Germany
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Ros Pérez M, Medina-Gómez G. [Obesity, adipogenesis and insulin resistance]. ACTA ACUST UNITED AC 2011; 58:360-9. [PMID: 21778123 DOI: 10.1016/j.endonu.2011.05.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2011] [Revised: 04/12/2011] [Accepted: 05/11/2011] [Indexed: 12/25/2022]
Abstract
Insulin resistance precedes the development of type 2 diabetes mellitus and is also a common denominator in the so-called metabolic syndrome. Although the cause of insulin resistance has not been fully elucidated, it seems clear that lifestyle changes, including little physical exercise and constant access to food, particularly in developed and economically emergent countries, as well as genetic factors, appear to have triggered the escalating incidence of diseases related to insulin resistance, including type 2 diabetes and metabolic syndrome. Obesity is considered as a risk factor for developing insulin resistance. Increased adipose tissue has been related to an increased production of pro-inflammatory cytokines which, together with fatty acids, appear to be responsible for the development of insulin resistance. Thus, a greater or lesser expansibility or ability of adipose tissue to store lipids also appears to play a significant role in the development of insulin resistance because overcoming of this capacity, which is variable in each case, would result in leaking of lipids to other tissues where they could interfere with insulin signaling. This article reviews various molecular mechanisms related to the development of insulin resistance and its relationship to expansibility of adipose tissue and obesity.
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Affiliation(s)
- Manuel Ros Pérez
- Departamento de Bioquímica, Fisiología y Genética Molecular, Universidad Rey Juan Carlos, Facultad de Ciencias de la Salud, Alcorcón, Madrid, España
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Gurnell M. 'Striking the Right Balance' in Targeting PPARgamma in the Metabolic Syndrome: Novel Insights from Human Genetic Studies. PPAR Res 2011; 2007:83593. [PMID: 17389771 PMCID: PMC1847466 DOI: 10.1155/2007/83593] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2006] [Revised: 12/13/2006] [Accepted: 12/13/2006] [Indexed: 12/03/2022] Open
Abstract
At a time when the twin epidemics of obesity and type 2 diabetes threaten to engulf even the most well-resourced Western healthcare systems, the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) has emerged as a
bona fide therapeutic target for treating human metabolic disease. The novel insulin-sensitizing antidiabetic thiazolidinediones (TZDs, e.g., rosiglitazone, pioglitazone), which are licensed for use in the treatment of type 2 diabetes, are high-affinity PPARγ ligands, whose beneficial effects extend beyond improvement in glycaemic control to include amelioration of dyslipidaemia, lowering of blood pressure, and favourable modulation of macrophage lipid handling and inflammatory responses. However, a major drawback to the clinical use of exisiting TZDs is weight gain, reflecting both enhanced adipogenesis and fluid retention, neither of which is desirable in a population that is already overweight and prone to cardiovascular disease. Accordingly, the “search is on” to identify the next generation of PPARγ modulators that will promote maximal clinical benefit by targeting specific facets of the metabolic syndrome (glucose intolerance/diabetes, dyslipidaemia, and hypertension), while simultaneously avoiding undesirable side effects of PPARγ activation (e.g., weight gain). This paper outlines the important clinical and laboratory observations made in human subjects harboring genetic variations in PPARγ that support such a therapeutic strategy.
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Affiliation(s)
- Mark Gurnell
- Department of Medicine, University of Cambridge, Addenbrooke's Hospital, Hills Road, Cambridge CB2 2QQ, UK
- *Mark Gurnell:
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Veilleux A, Caron-Jobin M, Noël S, Laberge PY, Tchernof A. Visceral adipocyte hypertrophy is associated with dyslipidemia independent of body composition and fat distribution in women. Diabetes 2011; 60:1504-11. [PMID: 21421806 PMCID: PMC3292324 DOI: 10.2337/db10-1039] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE We assessed whether subcutaneous and omental adipocyte hypertrophy are related to metabolic alterations independent of body composition and fat distribution in women. RESEARCH DESIGN AND METHODS Mean adipocyte diameter of paired subcutaneous and omental adipose tissue samples was obtained in lean to obese women. Linear regression models predicting adipocyte size in both adipose tissue depots were computed using body composition and fat distribution measures (n = 150). In a given depot, women with larger adipocytes than predicted by the regression were considered as having adipocyte hypertrophy, whereas women with smaller adipocytes than predicted were considered as having adipocyte hyperplasia. RESULTS Women characterized by omental adipocyte hypertrophy had higher plasma and VLDL triglyceride levels as well as a higher total-to-HDL cholesterol ratio compared with women characterized by omental adipocyte hyperplasia (P < 0.05). Conversely, women characterized by subcutaneous adipocyte hypertrophy or hyperplasia showed a similar lipid profile. In logistic regression analyses, a 10% enlargement of omental adipocytes increased the risk of hypertriglyceridemia (adjusted odds ratio [OR] 4.06, P < 0.001) independent of body composition and fat distribution measures. A 10% increase in visceral adipocyte number also raised the risk of hypertriglyceridemia (adjusted OR 1.55, P < 0.02). Associations between adipocyte size and homeostasis model assessment of insulin resistance were not significant once adjusted for adiposity and body fat distribution. CONCLUSIONS These results suggest that omental, but not subcutaneous, adipocyte hypertrophy is associated with an altered lipid profile independent of body composition and fat distribution in women.
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Affiliation(s)
- Alain Veilleux
- Endocrinology and Genomics, Laval University Medical Research Center, Québec, Canada
- Department of Food Science and Nutrition, Laval University, Québec, Canada
| | - Maude Caron-Jobin
- Endocrinology and Genomics, Laval University Medical Research Center, Québec, Canada
- Department of Food Science and Nutrition, Laval University, Québec, Canada
| | - Suzanne Noël
- Gynecology Unit, Laval University Medical Research Center, Québec, Canada
| | | | - André Tchernof
- Endocrinology and Genomics, Laval University Medical Research Center, Québec, Canada
- Department of Food Science and Nutrition, Laval University, Québec, Canada
- Corresponding author: André Tchernof,
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Abstract
OBJECTIVE The dominant-negative P467L mutation in peroxisome proliferator activated receptor-γ (PPARγ) was identified in insulin-resistant patients with hyperglycemia and lipodystrophy. In contrast, mice carrying the corresponding Pparg-P465L mutation have normal insulin sensitivity, with mild hyperinsulinemia. We hypothesized that murine Pparg-P465L mutation leads to covert insulin resistance, which is masked by hyperinsulinemia and increased pancreatic islet mass, to retain normal plasma glucose. RESEARCH DESIGN AND METHODS We introduced in Pparg(P465L/+) mice an Ins2-Akita mutation that causes improper protein folding and islet apoptosis to lower plasma insulin. RESULTS Unlike Ins2(Akita/+) littermates, male Pparg(P465L/+)Ins2(Akita/+) mice have drastically reduced life span with enhanced type 1 diabetes. Hyperglycemia in Ins2(Akita/+) females is mild. However, Pparg(P465L/+)Ins2(Akita/+) females have aggravated hyperglycemia, smaller islets, and reduced plasma insulin. In an insulin tolerance test, they showed smaller reduction in plasma glucose, indicating impaired insulin sensitivity. Although gluconeogenesis is enhanced in Pparg(P465L/+)Ins2(Akita/+) mice compared with Ins2(Akita/+), exogenous insulin equally suppressed gluconeogenesis in hepatocytes, suggesting that Pparg(P465L/+)Ins2(Akita/+) livers are insulin sensitive. Expression of genes regulating insulin sensitivity and glycogen and triglyceride contents suggest that skeletal muscles are equally insulin sensitive. In contrast, adipose tissue and isolated adipocytes from Pparg(P465L/+)Ins2(Akita/+) mice have impaired glucose uptake in response to exogenous insulin. Pparg(P465L/+)Ins2(Akita/+) mice have smaller fat depots composed of larger adipocytes, suggesting impaired lipid storage with subsequent hepatomegaly and hypertriglyceridemia. CONCLUSIONS PPARg-P465L mutation worsens hyperglycemia in Ins2(Akita/+) mice primarily because of adipose-specific insulin resistance and altered storage function. This underscores the important interplay between insulin and PPARγ in adipose tissues in diabetes.
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Affiliation(s)
- Avani A. Pendse
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Lance A. Johnson
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Yau-Sheng Tsai
- Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Nobuyo Maeda
- Department of Pathology and Laboratory Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
- Corresponding author: Nobuyo Maeda,
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Abstract
Common obesity and inherited lipodystrophies, rare disorders characterized by a partial (familial partial lipodystrophy; FPLD) or complete (congenital generalized lipodystrophy; CGL) lack of adipose tissue, are both associated with metabolic complications such as insulin resistance and type 2 diabetes. Mutations in the transcription factor peroxisome proliferator activated receptor (PPAR)γ and a number of its downstream target genes result in lipodystrophy. We hypothesize that signalling by another transcription factor, sterol response element binding protein (SREBP)1c, also needs to be intact to prevent lipodystrophy. The future challenge is to understand how inactivation of such central players or of their upstream regulators or downstream effectors can affect adipose tissue in a depot-specific fashion.
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Affiliation(s)
- Ellen H Jeninga
- Department of Metabolic and Endocrine Diseases, UMC Utrecht, Lundlaan 6, 3584 EA Utrecht, The Netherlands
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Abstract
Metabolic syndrome (MetS) is a constellation of risk factors including insulin resistance, central obesity, dyslipidemia and hypertension that markedly increase the risk of Type 2 diabetes (T2DM) and cardiovascular disease (CVD). The peroxisome proliferators-activated receptor (PPAR) isotypes, PPARα, PPARδ/ß and PPARγ are ligand-activated nuclear transcription factors, which modulate the expression of an array of genes that play a central role in regulating glucose, lipid and cholesterol metabolism, where imbalance can lead to obesity, T2DM and CVD. They are also drug targets, and currently, PPARα (fibrates) and PPARγ (thiazolodinediones) agonists are in clinical use for treating dyslipidemia and T2DM, respectively. These metabolic characteristics of the PPARs, coupled with their involvement in metabolic diseases, mean extensive efforts are underway worldwide to develop new and efficacious PPAR-based therapies for the treatment of additional maladies associated with the MetS. This article presents an overview of the functional characteristics of three PPAR isotypes, discusses recent advances in our understanding of the diverse biological actions of PPARs, particularly in the vascular system, and summarizes the developmental status of new single, dual, pan (multiple) and partial PPAR agonists for the clinical management of key components of MetS, T2DM and CVD. It also summarizes the clinical outcomes from various clinical trials aimed at evaluating the atheroprotective actions of currently used fibrates and thiazolodinediones.
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Affiliation(s)
- Salman Azhar
- Geriatric Research, Education & Clinical Center, VA Palo Alto Health Care System, Palo Alto, CA, USA.
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Abstract
For long viewed as passive lipid storage depots, adipocytes are now recognised as key players in the pathogenesis of insulin resistance and metabolic disease. In parallel, the last two decades of research have seen the emergence of transcription factors of the peroxisome proliferator-activated receptor (PPAR) family as central regulators of lipid and glucose homeostasis and molecular targets for drugs to treat hyper-lipidaemia and type 2 diabetes mellitus. In this review we discuss the characteristics of PPARs and the role of the different isotypes in adipocyte biology.
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Arck P, Toth B, Pestka A, Jeschke U. Nuclear receptors of the peroxisome proliferator-activated receptor (PPAR) family in gestational diabetes: from animal models to clinical trials. Biol Reprod 2010; 83:168-76. [PMID: 20427759 DOI: 10.1095/biolreprod.110.083550] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is defined as impaired glucose tolerance and affects 2%-8% of all pregnancies. Among other complications, GDM can lead to the development of type 2 diabetes mellitus (DM 2) in both mother and child. Peroxisome proliferator-activated receptors (PPARs) are major regulators of glucose and lipid metabolism. Furthermore, PPARs are mediators of inflammation and angiogenesis and are involved in the maternal adaptational dynamics during pregnancy to serve the requirements of the growing fetus. PPARs were originally named for their ability to induce hepatic peroxisome proliferation in mice in response to xenobiotic stimuli. The expression of three PPAR isoforms, alpha, beta/delta, and gamma, have been described. Each of them is encoded by different genes; however, they share 60%-80% homology in their ligand-binding and DNA-binding domains. PPARs are involved in trophoblast differentiation, invasion, metabolism, and parturition and are expressed in invasive extravillous trophoblast and villous trophoblast cells. Nuclear receptors, to which PPARs belong, are promising targets for disease-specific treatment strategies because they act as transcription factors controlling cellular processes at the level of gene expression and may produce selective alterations in downstream gene expression. To date, PPAR agonists are therapeutically used in patients with DM 2 and in patients with reproductive disorders such as polycystic ovary syndrome. Because of safety concerns and limited data, PPAR agonists are not yet included in GDM-related treatment strategies. Our objective herein is to review newly emerging generations of selective PPAR modulators and panagonists, which may have potent therapeutic implications in the context of GDM.
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Affiliation(s)
- Petra Arck
- Center for Internal Medicine, Charité University Medicine Berlin, Berlin, Germany
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Leyvraz C, Suter M, Verdumo C, Calmes JM, Paroz A, Darimont C, Gaillard RC, Pralong FP, Giusti V. Selective effects of PPARgamma agonists and antagonists on human pre-adipocyte differentiation. Diabetes Obes Metab 2010; 12:195-203. [PMID: 19895635 DOI: 10.1111/j.1463-1326.2009.01149.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIM The insulin sensitizer rosiglitazone (RTZ) acts by activating peroxisome proliferator and activated receptor gamma (PPAR gamma), an effect accompanied in vivo in humans by an increase in fat storage. We hypothesized that this effect concerns PPARgamma(1) and PPARgamma(2) differently and is dependant on the origin of the adipose cells (subcutaneous or visceral). To this aim, the effect of RTZ, the PPARgamma antagonist GW9662 and lentiviral vectors expressing interfering RNA were evaluated on human pre-adipocyte models. METHODS Two models were investigated: the human pre-adipose cell line Chub-S7 and primary pre-adipocytes derived from subcutaneous and visceral biopsies of adipose tissue (AT) obtained from obese patients. Cells were used to perform oil-red O staining, gene expression measurements and lentiviral infections. RESULTS In both models, RTZ was found to stimulate the differentiation of pre-adipocytes into mature cells. This was accompanied by significant increases in both the PPARgamma(1) and PPARgamma(2) gene expression, with a relatively stronger stimulation of PPARgamma(2). In contrast, RTZ failed to stimulate differentiation processes when cells were incubated in the presence of GW9662. This effect was similar to the effect observed using interfering RNA against PPARgamma(2). It was accompanied by an abrogation of the RTZ-induced PPARgamma(2) gene expression, whereas the level of PPARgamma(1) was not affected. CONCLUSIONS Both the GW9662 treatment and interfering RNA against PPARgamma(2) are able to abrogate RTZ-induced differentiation without a significant change of PPARgamma(1) gene expression. These results are consistent with previous results obtained in animal models and suggest that in humans PPARgamma(2) may also be the key isoform involved in fat storage.
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Affiliation(s)
- C Leyvraz
- Service of Endocrinology, Diabetology and Metabolism, University Hospital CHUV, Lausanne, Switzerland
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48
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Abstract
Insulin resistance is a major factor in the pathogenesis of type 2 diabetes and underpins the strong association between obesity and diabetes. Paradoxically, the metabolic consequences of having 'too much' fat (obesity) are remarkably similar to those of having 'too little' fat (lipodystrophy): a finding that has generated considerable interest in a rare disease. In both cases, excess energy accumulates as lipid in ectopic sites such as the liver (fatty liver) and skeletal muscle, where it plays a central role in the pathogenesis of insulin resistance, dyslipidemia and type 2 diabetes. Human lipodystrophies are characterised by a total or partial deficiency of body fat, and may be inherited or acquired in origin. Genetically engineered mice with generalised lipodystrophy manifest many of the features of the human disorder, including hyperphagia, fatty liver, hypertriglyceridaemia, insulin resistance and type 2 diabetes, providing a useful tractable model of the human disorder. Partial lipodystrophy, which causes similar, albeit milder, metabolic problems in humans has been more difficult to mimic in the mouse. This review discusses key translational studies in mice with generalised lipodystrophy, including fat transplantation and the use of recombinant leptin replacement therapy. These studies have been instrumental in advancing our understanding of the underlying molecular pathogenesis of ectopic lipid accumulation and insulin resistance, and have prompted the initiation and subsequent adoption of leptin replacement therapy in human lipodystrophies. This review also considers the possible reasons for the apparent difficulties in generating mouse models of partial lipodystrophy, such as interspecies differences in the distribution of fat depots and the apparent lack of sexual dimorphism in fat mass and distribution in mice compared with the dramatic differences present in adult humans.
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Affiliation(s)
- David B Savage
- Metabolic Research Laboratories, Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK.
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49
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Abstract
Obesity is characterized by an increase of adipose tissue as a result of a positive imbalance between food intake and energy expenditure. Recent studies have indicated that adipocyte function is more complex than expected, since these cells have multiple functions and are integrated in a homeostatic network to optimize energy resources. As metabolic sensors in the body, adipocytes and the surrounding stromal vascular cells produce and secrete autocrine, paracrine and endocrine factors, able to regulate aspects involved in the development of adipocytes, as well as effects in peripheral organs important for metabolism. Regulation of these endocrine factors could lead to new therapeutic approaches targeted at aspects related to adipogenesis, preadipocyte proliferation and differentiation, inflammatory cytokine release and secretion, adipose tissue vascularization, and regulation of lipid metabolism or, alternatively, regulation of energy dissipation in mitochondria. In the study of the mechanisms of adipogenesis and remodulation of adipose tissue with respect to adipocyte size and function, an alternative and unorthodox strategy to improve obesity-associated metabolic complications could consist of increasing the storage capacity of adipose tissue to prevent a toxic response known as lipotoxicity.
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Affiliation(s)
- Gema Medina-Gómez
- Departamento de Bioquímica y Fisiología, Universidad Rey Juan Carlos, Facultad de Ciencias de la Salud, Alarcón, Madrid, España.
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50
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Virtue S, Vidal-Puig A. Adipose tissue expandability, lipotoxicity and the Metabolic Syndrome--an allostatic perspective. Biochim Biophys Acta Mol Cell Biol Lipids 2010; 1801:338-49. [PMID: 20056169 DOI: 10.1016/j.bbalip.2009.12.006] [Citation(s) in RCA: 658] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 12/15/2009] [Accepted: 12/16/2009] [Indexed: 02/07/2023]
Abstract
While the link between obesity and type 2 diabetes is clear on an epidemiological level, the underlying mechanism linking these two common disorders is not as clearly understood. One hypothesis linking obesity to type 2 diabetes is the adipose tissue expandability hypothesis. The adipose tissue expandability hypothesis states that a failure in the capacity for adipose tissue expansion, rather than obesity per se is the key factor linking positive energy balance and type 2 diabetes. All individuals possess a maximum capacity for adipose expansion which is determined by both genetic and environmental factors. Once the adipose tissue expansion limit is reached, adipose tissue ceases to store energy efficiently and lipids begin to accumulate in other tissues. Ectopic lipid accumulation in non-adipocyte cells causes lipotoxic insults including insulin resistance, apoptosis and inflammation. This article discusses the links between adipokines, inflammation, adipose tissue expandability and lipotoxicity. Finally, we will discuss how considering the concept of allostasis may enable a better understanding of how diabetes develops and allow the rational design of new anti diabetic treatments.
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Affiliation(s)
- Sam Virtue
- Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Box 289, Level 4, Addenbrooke's Hospital, Cambridge CB2 0QQ, UK.
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