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Yousef MI, Abd HH, Helmy YM, Kamel MAN. Synergistic effect of curcumin and chitosan nanoparticles on nano-hydroxyapatite-induced reproductive toxicity in rats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:9362-9376. [PMID: 33141380 DOI: 10.1007/s11356-020-11395-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 10/22/2020] [Indexed: 06/11/2023]
Abstract
Although the toxicity/biocompatibility of hydroxyapatite nanoparticles (HAPNPs), a prospective nano-biomaterial, is extensively studied, its interaction on the reproductive system following exposure is less exploited. In the present study, male rats were exposed to HAPNPs (300 mg/kg BW) to determine its possible reproductive toxicity. Also, the protective effects of chitosan (CSNPs, 280 mg/kg BW) and/or curcumin (CurNPs, 15 mg/kg BW) nanoparticles against HAPNPs-induced reproductive toxicity were studied. Animals were orally gavage daily with respective doses for 45 consecutive days. The obtained results indicated that HAPNPs caused a significant decrease in sperm count, sperm motility, testosterone hormone, steroidogenic enzymes (17-ketosteroid reductase and 17β-hydroxysteroid dehydrogenase), and antioxidant enzymes (glutathione peroxidase, glutathione S-transferase, catalase, and superoxide dismutase) in addition to total antioxidant capacity and reduced glutathione. LH and FSH, abnormal sperm, oxidative stress parameters (thiobarbituric acid-reactive substances (TBARS), nitric oxide (NO), and 8-hydroxy-deoxyguanosine (8-OHdG)), p53, TNFα, and interleukin-6 were significantly increased. The DNA damage was also analyzed by assaying 8-OHdG level which is considered as an indicator of genotoxicity and also suppression of the gene expression of mtTFA, induction of UCP2. Similarly, the histopathological evaluation was also changed following exposure to HAPNPs. The antioxidant activity of CSNPs and CurNPs showed mitigating effect against reproductive deterioration induced by HAPNPs throughout improvements in semen characteristics, sex hormones, inflammatory factors, and antioxidant status. The present study concluded that HAPNPs induced reproductive toxicity and it is important to use nano-antioxidants CSNPs and CurNPs as protective agents.
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Affiliation(s)
- Mokhtar Ibrahim Yousef
- Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horreya Avenue, Chatby, PO Box 832, Alexandria, 21526, Egypt.
| | - Haitham Hassan Abd
- Department of Environmental Studies, Institute of Graduate Studies and Research, Alexandria University, 163 Horreya Avenue, Chatby, PO Box 832, Alexandria, 21526, Egypt
| | - Yasser Mohamed Helmy
- Scientific Consultant at Pharco Company for Pharmaceutical Products, Alexandria, Egypt
| | - Maher Abdel-Nabi Kamel
- Department of Biochemistry, Medical Research Institute, Alexandria University, Alexandria, Egypt
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2
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Pérez-Matute P, Pichel JG, Iñiguez M, Recio-Fernández E, Pérez-Martínez L, Torrens R, Blanco JR, Oteo JA. Maraviroc ameliorates the increased adipose tissue macrophage recruitment induced by a high-fat diet in a mouse model of obesity. Antivir Ther 2016; 22:163-168. [PMID: 27725337 DOI: 10.3851/imp3099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2016] [Indexed: 10/20/2022]
Abstract
BACKGROUND Any strategy designed to decrease the macrophage content in adipose tissue (AT) is of great value as a way to decrease inflammation in this fat depot and also as a way to prevent or treat obesity and associated disorders. Maraviroc (MVC), a CCR5 antagonist approved for the treatment of HIV-infected patients, has beneficial effects on metabolism. The objective of this study was to investigate the effects of MVC on AT macrophage recruitment in a mouse model of obesity. The plausible underlying mechanisms of action were also investigated. METHODS 32 male C57BL/6 mice were randomly assigned to the following groups: control, MVC (300 mg/l MVC in drinking water), high-fat diet (HFD) or HFD+MVC. After 16 weeks of treatment, histopathological and molecular analyses were performed on epididymal fat. RESULTS Our results demonstrated that MVC reduced the presence of macrophages in epididymal fat despite the ingestion of an HFD. The inhibition of MCP-1 gene expression and JNK signalling pathway along with the upregulation of protective cytokines such as cardiotrophin-1 could contribute to these actions. MVC effects on AT macrophage recruitment were associated with a lower body weight gain and a partial improvement in insulin resistance despite an HFD. CONCLUSIONS We have demonstrated the ability of MVC to ameliorate the increased AT macrophage recruitment induced by an HFD in a mouse model of obesity. These actions could be of interest when designing antiretroviral treatments in HIV-patients.
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Affiliation(s)
- Patricia Pérez-Matute
- Infectious Diseases Department, Center for Biomedical Research of La Rioja, Hospital San Pedro, Logroño, Spain
| | - José G Pichel
- Lung Cancer Unit, Center for Biomedical Research of La Rioja, Logroño, Spain
| | - María Iñiguez
- Genomics Core Facility, Center for Biomedical Research of La Rioja, Logroño, Spain
| | - Emma Recio-Fernández
- Infectious Diseases Department, Center for Biomedical Research of La Rioja, Hospital San Pedro, Logroño, Spain
| | - Laura Pérez-Martínez
- Infectious Diseases Department, Center for Biomedical Research of La Rioja, Hospital San Pedro, Logroño, Spain
| | - Raquel Torrens
- Lung Cancer Unit, Center for Biomedical Research of La Rioja, Logroño, Spain
| | - José Ramón Blanco
- Infectious Diseases Department, Center for Biomedical Research of La Rioja, Hospital San Pedro, Logroño, Spain
| | - José Antonio Oteo
- Infectious Diseases Department, Center for Biomedical Research of La Rioja, Hospital San Pedro, Logroño, Spain
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Gerö D, Szabo C. Glucocorticoids Suppress Mitochondrial Oxidant Production via Upregulation of Uncoupling Protein 2 in Hyperglycemic Endothelial Cells. PLoS One 2016; 11:e0154813. [PMID: 27128320 PMCID: PMC4851329 DOI: 10.1371/journal.pone.0154813] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/19/2016] [Indexed: 11/19/2022] Open
Abstract
Diabetic complications are the leading cause of morbidity and mortality in diabetic patients. Elevated blood glucose contributes to the development of endothelial and vascular dysfunction, and, consequently, to diabetic micro- and macrovascular complications, because it increases the mitochondrial proton gradient and mitochondrial oxidant production. Therapeutic approaches designed to counteract glucose-induced mitochondrial reactive oxygen species (ROS) production in the vasculature are expected to show efficacy against all diabetic complications, but direct pharmacological targeting (scavenging) of mitochondrial oxidants remains challenging due to the high reactivity of some of these oxidant species. In a recent study, we have conducted a medium-throughput cell-based screening of a focused library of well-annotated pharmacologically active compounds and identified glucocorticoids as inhibitors of mitochondrial superoxide production in microvascular endothelial cells exposed to elevated extracellular glucose. The goal of the current study was to investigate the mechanism of glucocorticoids' action. Our findings show that glucocorticoids induce the expression of the mitochondrial UCP2 protein and decrease the mitochondrial potential. UCP2 silencing prevents the protective effect of the glucocorticoids on ROS production. UCP2 induction also increases the oxygen consumption and the "proton leak" in microvascular endothelial cells. Furthermore, glutamine supplementation augments the effect of glucocorticoids via further enhancing the expression of UCP2 at the translational level. We conclude that UCP2 induction represents a novel experimental therapeutic intervention in diabetic vascular complications. While direct repurposing of glucocorticoids may not be possible for the therapy of diabetic complications due to their significant side effects that develop during chronic administration, the UCP2 pathway may be therapeutically targetable by other, glucocorticoid-independent pharmacological means.
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Affiliation(s)
- Domokos Gerö
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas, United States of America
- University of Exeter Medical School, Exeter, United Kingdom
- * E-mail:
| | - Csaba Szabo
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas, United States of America
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4
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Hanafi MY, Abdelkhalek TM, Saad MI, Saleh MM, Haiba MM, Kamel MA. Diabetes-induced perturbations are subject to intergenerational transmission through maternal line. J Physiol Biochem 2016; 72:315-26. [PMID: 27038466 DOI: 10.1007/s13105-016-0483-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 03/21/2016] [Indexed: 01/09/2023]
Abstract
The hypothesis of fetal origins of adult disease states that early life events program the occurrence of significant adult diseases, including diabetes and obesity. Maternal diabetes is associated with general stress environment for developing fetus, and gestational diabetes is an independent risk factor for type 2 diabetes and metabolic syndrome in offspring. Intra-uterine fetal programming of fetal tissues exposes the offspring to increased risk of impaired glucose tolerance, type 2 diabetes, and cardiovascular disease. Here, we examined the transmission of maternal diabetes-induced fetal programming in second generation and compared maternal and paternal routes of intergenerational effects. We organized 40 Wistar rats into three groups, male offspring of diabetic mothers, female offspring of diabetic mothers, and offspring of control mothers. These groups were mated with normal healthy rats to assess the effect of grand-maternal diabetes on pregnancy outcome in F2 rats, as well as glucose-sensing parameters, insulin resistance, and glucose tolerance prenatally and postnatally. We found that F2 offspring of diabetic mothers had impaired glucose sensing, increased oxidative stress, insulin resistance, and impaired glucose tolerance, and these effects were more prominent in the F2 offspring of F1 female rats (F2-DF1F). We deduce that fetal programming of maternal diabetes is mostly transmitted through maternal line across two generations.
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MESH Headings
- Adipose Tissue/embryology
- Adipose Tissue/metabolism
- Animals
- Diabetes Mellitus, Experimental/blood
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 2/blood
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Female
- Fetal Development
- Gene Expression Regulation, Developmental
- Glucose Intolerance/blood
- Glucose Intolerance/etiology
- Glucose Intolerance/metabolism
- Glucose Intolerance/pathology
- Insulin Resistance
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Liver/embryology
- Liver/metabolism
- Male
- Maternal Inheritance
- Mitochondrial Dynamics
- Muscle, Skeletal/embryology
- Muscle, Skeletal/metabolism
- Organelle Biogenesis
- Oxidative Stress
- Pancreas/embryology
- Pancreas/metabolism
- Pancreas/pathology
- Pregnancy
- Pregnancy Complications/blood
- Pregnancy Complications/metabolism
- Pregnancy Complications/pathology
- Pregnancy Complications/physiopathology
- Rats, Wistar
- Streptozocin
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Affiliation(s)
- Mervat Y Hanafi
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya, Avenue, P.O. Box 21561, Alexandria, Egypt
| | - Taha M Abdelkhalek
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Mohamed I Saad
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya, Avenue, P.O. Box 21561, Alexandria, Egypt.
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Melbourne, Victoria, Australia.
| | - Moustafa M Saleh
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Maha M Haiba
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya, Avenue, P.O. Box 21561, Alexandria, Egypt
| | - Maher A Kamel
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya, Avenue, P.O. Box 21561, Alexandria, Egypt
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5
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Hanafi MY, Saleh MM, Saad MI, Abdelkhalek TM, Kamel MA. Transgenerational effects of obesity and malnourishment on diabetes risk in F2 generation. Mol Cell Biochem 2015; 412:269-80. [PMID: 26708218 DOI: 10.1007/s11010-015-2633-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/15/2015] [Indexed: 01/19/2023]
Abstract
Transgenerational inheritance of various diseases and phenotypes has been demonstrated in diverse species and involves various epigenetic markers. Obesity and malnourishment are nutritional stresses that have effects on offspring through increasing their risk of diabetes and/or obesity. Obesity and malnourishment both affect glucose metabolism and alter oxidative stress parameters in key organs. We induced obesity and malnutrition in F0 female rats by the use of obesogenic diet and protein-deficient diet, respectively. F0 obese and malnourished females were mated with control males and their offspring (F1 generation) were maintained on control diets. The male and female F1 offspring were mated with controls and the resultant offspring (F2 generation) were maintained on control diet. Glucose-sensing markers, glucose metabolism, indicators of insulin resistance and oxidative stress parameters were assessed during fetal development and till the adulthood of the offspring. Glucose-sensing genes were significantly over-expressed in distinct fetal tissues of F2 offspring of malnourished F1 females (F2-MF1F), specifically in fetal pancreas, liver, and adipose tissue. Nuclear and mitochondrial 8-oxo-dG DNA content was significantly elevated in F2-MF1F fetal pancreas. Maternal FBG was significantly elevated in F2-MF1F and F2 offspring of obese F1 females (F2-OF1F) during pregnancy. Males and females offspring of F2-OF1 exhibited significantly elevated FBG and impaired OGTT. Offspring of F2-MF1F showed similar results, while that of F2-MF1M did not significantly deviate from controls. F2-OF1F and F2-MF1F offspring exhibited significant deviation in insulin levels and HOMA-IR levels from controls. Malnourishment has a stronger transgenerational effect through maternal line compared to obesity and malnourishment through paternal line in increasing risk of diabetes in F2 generation.
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Affiliation(s)
- Mervat Y Hanafi
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya Avenue, P.O. Box 21561, Alexandria, Egypt
| | - Moustafa M Saleh
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Mohamed I Saad
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya Avenue, P.O. Box 21561, Alexandria, Egypt.
- The Ritchie Centre, Hudson Institute of Medical Research, Monash University, Melbourne, VIC, Australia.
| | - Taha M Abdelkhalek
- Department of Human Genetics, Medical Research Institute, Alexandria University, Alexandria, Egypt
| | - Maher A Kamel
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 Elhorreya Avenue, P.O. Box 21561, Alexandria, Egypt
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Pheiffer C, Jacobs C, Patel O, Ghoor S, Muller C, Louw J. Expression of UCP2 in Wistar rats varies according to age and the severity of obesity. J Physiol Biochem 2015; 72:25-32. [PMID: 26621256 DOI: 10.1007/s13105-015-0454-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 11/24/2015] [Indexed: 01/26/2023]
Abstract
Obesity, a complex metabolic disorder, is characterized by mitochondrial dysfunction and oxidative stress. Increased expression of uncoupling protein 2 (UCP2) during obesity is an adaptive response to suppress the production of reactive oxygen species. The aims of this study were to compare the expression of UCP2 in diet-induced obese Wistar rats that differed according to age and their severity of obesity, and to compare UCP2 expression in the liver and muscle of these rats. UCP2 messenger RNA and protein expression was increased 4.6-fold (p < 0.0001) and 3.0-fold (p < 0.05), respectively, in the liver of the older and heavier rats. In contrast, UCP2 expression was decreased twofold (p < 0.005) in the muscle of these rats, while UCP3 messenger RNA (mRNA) was increased twofold (p < 0.01). Peroxisome proliferator-activated receptor alpha (PPARα) was similarly increased (3.0-fold, p < 0.05) in the liver of the older and more severe obese rats. Total protein content was increased (2.3-fold, p < 0.0001), while 5' adenosine monophosphate-activated protein kinase (AMPK) activity was decreased (1.3-fold, p = 0.05) in the liver of the older, heavier rats. No difference in total protein content and AMPK expression was observed in the muscle of these rats. This study showed that the expression of UCP2 varies according to age and the severity of obesity and supports the widely held notion that increased UCP2 expression is an adaptive response to increased fatty acid β-oxidation and reactive oxygen species production that occurs during obesity. An understanding of metabolic adaptation is imperative to gain insight into the underlying causes of disease, thus facilitating intervention strategies to combat disease progression.
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Affiliation(s)
- Carmen Pheiffer
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa.
| | - Carvern Jacobs
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa
| | - Oelfah Patel
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa
| | - Samira Ghoor
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa
| | - Christo Muller
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa
| | - Johan Louw
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505, South Africa
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7
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André C, Dinel AL, Ferreira G, Layé S, Castanon N. Diet-induced obesity progressively alters cognition, anxiety-like behavior and lipopolysaccharide-induced depressive-like behavior: focus on brain indoleamine 2,3-dioxygenase activation. Brain Behav Immun 2014; 41:10-21. [PMID: 24681251 DOI: 10.1016/j.bbi.2014.03.012] [Citation(s) in RCA: 164] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 03/06/2014] [Accepted: 03/18/2014] [Indexed: 12/12/2022] Open
Abstract
Obesity is associated with a high prevalence of mood symptoms and cognitive dysfunctions that emerges as significant risk factors for important health complications such as cardiovascular diseases and type 2 diabetes. It is therefore important to identify the dynamic of development and the pathophysiological mechanisms underlying these neuropsychiatric symptoms. Obesity is also associated with peripheral low-grade inflammation and increased susceptibility to immune-mediated diseases. Excessive production of proinflammatory cytokines and the resulting activation of the brain tryptophan catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) have been shown to promote neurobehavioral complications, particularly depression. In that context, questions arise about the impact of diet-induced obesity on the onset of neuropsychiatric alterations and the increased susceptibility to immune-mediated diseases displayed by obese patients, particularly through brain IDO activation. To answer these questions, we used C57Bl/6 mice exposed to standard diet or western diet (WD; consisting of palatable energy-dense food) since weaning and for 20 weeks. We then measured inflammatory and behavioral responses to a systemic immune challenge with lipopolysaccharide (LPS) in experimental conditions known to alter cognitive and emotional behaviors independently of any motor impairment. We first showed that in absence of LPS, 9 weeks of WD is sufficient to impair spatial recognition memory (in the Y-maze). On the other hand, 18 weeks of WD increased anxiety-like behavior (in the elevated plus-maze), but did not affect depressive-like behavior (in the tail-suspension and forced-swim tests). However, 20 weeks of WD altered LPS-induced depressive-like behavior compared to LPS-treated lean mice and exacerbated hippocampal and hypothalamic proinflammatory cytokine expression and brain IDO activation. Taken together, these results show that WD exposure alters cognition and anxiety in unstimulated conditions and enhances activation of neurobiological mechanisms underlying depression after immune stimulation. They suggest therefore that obesity, and possibly obesity-associated inflammatory priming, may represent a vulnerability state to immune-mediated depressive symptoms.
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Affiliation(s)
- Caroline André
- INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France
| | - Anne-Laure Dinel
- INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France
| | - Guillaume Ferreira
- INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France
| | - Sophie Layé
- INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France
| | - Nathalie Castanon
- INRA, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France; Université de Bordeaux, Nutrition and Integrative Neurobiology, UMR 1286, 33076 Bordeaux, France.
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8
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Kamel MA, Helmy MH, Hanafi MY, Mahmoud SA, Abo Elfetooh H. Impaired peripheral glucose sensing in F1 offspring of diabetic pregnancy. J Physiol Biochem 2014; 70:685-99. [PMID: 24895245 DOI: 10.1007/s13105-014-0338-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2013] [Accepted: 05/19/2014] [Indexed: 01/15/2023]
Abstract
Maternal diabetes can induce permanent changes in glucose homeostasis that can occur pre- and post-natal and leads to type 2 diabetes in adulthood. This study aimed to investigate the effect of maternal diabetes on the F1 offspring peripheral glucose sensing and mitochondrial biogenesis in an attempt to clarify the mechanism of diabetogenic programming. Two groups of female Wistar rats were used (diabetic and control); diabetes was neonatally induced by STZ injection to 5-day old rats. After the pregnancy and delivery, the offspring were weaned to control diet or high-caloric (HCD) diet and followed up for 30 weeks. Every 5 weeks, OGTT was constructed, and serum and tissues were obtained for the assessment of mTFA, mtDNA, UCP2, insulin receptor (IR), phospho-insulin receptor (phospho-IR), and GLUT4. The result indicated impaired glucose tolerance (IGT) and insulin resistance in the offspring under control diet at the 15th week of age and thereafter while those offspring under HCD showed IGT at 10th week, and diabetes was evidenced at the 25th week of age. This defect in glucose metabolism was preceded by impairment in the phosphorylation of IR and decreased IR and Glut4 that cause impaired glucose sensing together with inhibited mitochondrial biogenesis in muscle and adipose tissues. This study indicated that maternal diabetes caused impaired glucose sensing and insulin resistance in the peripheral tissues and caused change in the expression of genes involved in mitochondrial biogenesis and function. Post-natal feeding with HCD may accelerate these changes. Male F1 offspring appears to be more sensitive than females for fetal programming of T2D.
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MESH Headings
- Adipose Tissue/metabolism
- Animals
- Animals, Newborn
- DNA, Mitochondrial/genetics
- DNA, Mitochondrial/metabolism
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes, Gestational/metabolism
- Diet
- Energy Intake
- Female
- Gene Expression
- Glucose/metabolism
- Glucose Tolerance Test
- Glucose Transporter Type 4/metabolism
- Insulin Resistance
- Ion Channels/genetics
- Male
- Mitochondria/metabolism
- Mitochondrial Proteins/genetics
- Muscle, Skeletal/metabolism
- Pregnancy
- Pregnancy in Diabetics/metabolism
- Prenatal Exposure Delayed Effects/etiology
- Prenatal Exposure Delayed Effects/genetics
- Prenatal Exposure Delayed Effects/metabolism
- Rats
- Rats, Wistar
- Receptor, Insulin/metabolism
- Uncoupling Protein 2
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Affiliation(s)
- Maher A Kamel
- Department of Biochemistry, Medical Research Institute, Alexandria University, 165 El-Horreya Street, Alexandria, Egypt,
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GARCIA-DIAZ DF, LOPEZ-LEGARREA P, QUINTERO P, MARTINEZ JA. Vitamin C in the Treatment and/or Prevention of Obesity. J Nutr Sci Vitaminol (Tokyo) 2014; 60:367-79. [DOI: 10.3177/jnsv.60.367] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
| | | | - Pablo QUINTERO
- Department of Gastroenterology, School of Medicine, Pontifical Catholic University of Chile
| | - Jose Alfredo MARTINEZ
- CIBERobn. Fisiopatología de la Obesidad y Nutrición, Instituto de Salud Carlos III
- Department of Food Sciences and Physiology, University of Navarra
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10
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Bueno AA, Habitante CA, Oyama LM, Estadella D, Ribeiro EB, Oller do Nascimento CM. White adipose tissue re-growth after partial lipectomy in high fat diet induced obese wistar rats. J Physiol Sci 2011; 61:55-63. [PMID: 21140253 PMCID: PMC10717058 DOI: 10.1007/s12576-010-0122-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 10/31/2010] [Indexed: 11/28/2022]
Abstract
The effects of partial removal of epididymal (EPI) and retroperitoneal (RET) adipose tissues (partial lipectomy) on the triacylglycerol deposition of high fat diet induced obese rats were analyzed, aiming to challenge the hypothesized body fat regulatory system. Male 28-day-old wistar rats received a diet enriched with peanuts, milk chocolate and sweet biscuits during the experimental period. At the 90th day of life, rats were submitted to either lipectomy (L) or sham surgery. After 7 or 30 days, RET, EPI, liver, brown adipose tissue (BAT), blood and carcass were obtained and analyzed. Seven days following surgery, liver lipogenesis rate and EPI relative weight were increased in L. After 30 days, L, RET and EPI presented increased lipogenesis, lipolysis and percentage of small area adipocytes. L rats also presented increased liver malic enzyme activity, BAT lipogenesis, and triacylglycerol and corticosterone serum levels. The partial removal of visceral fat pads affected the metabolism of high fat diet obese rats, which leads to excised tissue re-growth and possibly compensatory growth of non-excised depots at a later time.
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Affiliation(s)
- Allain Amador Bueno
- Institute of Brain Chemistry and Human Nutrition, London Metropolitan University, 166-220 Holloway Road, London, N7 8DB, UK
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12
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Zhang CM, Gu Y, Qing DN, Zhu JG, Zhu C, Zhang M, Guo XR. Tissue-specific distribution of uncoupling proteins in normal rats and rats with high-fat-diet-induced obesity. Mol Biol Rep 2009; 37:3177-82. [PMID: 19834821 DOI: 10.1007/s11033-009-9898-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 10/02/2009] [Indexed: 01/24/2023]
Abstract
Uncoupling proteins (UCPs) are a proton transporter family located in the mitochondrial inner membrane. Thus far, five molecules (UCP1-UCP5) have been identified as members of the UCP family. Recently, UCPs have attracted considerable interest in research on energy metabolism and obesity. However, to date, no study has focused on a comprehensive and systematic evaluation of the tissue-specific distribution of UCPs in obese individuals. Our study presents evidence of differential tissue expression profiles of five isoforms of UCPs in normal and diet-induced obese (DIO) rats using real-time polymerase chain reaction (PCR) analysis. The results clearly show that the tissue-specific expression patterns of individual isoforms between DIO and normal rats are quite distinct, which suggests a close relationship between the alterations in UCP expression and dietary obesity.
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Affiliation(s)
- Chun-Mei Zhang
- Department of Pediatrics, Nanjing Maternal and Child Health Hospital of Nanjing Medical University, Nanjing, China
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Garcia-Diaz DF, Campion J, Milagro FI, Paternain L, Solomon A, Martinez JA. Ascorbic acid oral treatment modifies lipolytic response and behavioural activity but not glucocorticoid metabolism in cafeteria diet-fed rats. Acta Physiol (Oxf) 2009; 195:449-57. [PMID: 19040713 DOI: 10.1111/j.1748-1716.2008.01942.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIM To analyse the effects of vitamin C (VC), a potent dietary antioxidant, oral supplementation on body weight gain, behavioural activity, lipolytic response and glucocorticoid metabolism in the early stages of diet-induced overweight in rats. METHODS Food intake, locomotive activity and faecal corticosterone were assessed during the 14 day trial period. After 2 weeks, the animals were sacrificed and the body composition, biochemical markers and lipolytic response from isolated adipocytes from retroperitoneal white adipose tissue were examined. RESULTS The intake of a high-fat diet by rats induced a significant increase in body weight, adiposity and insulin resistance markers as well as a decrease in faecal corticosterone levels compared with standard diet-fed rats. Interestingly, the animals fed on the cafeteria diet showed a significant increase in the isoproterenol-induced lipolytic response in isolated adipocytes. Furthermore, this cafeteria-fed group showed a reduced locomotive behaviour than the control rats. On the other hand, oral VC supplementation in animals receiving the high-fat diet restored the cafeteria diet effect in some of the analysed variables such as final body weight and plasma insulin to control group levels. Remarkably, increases in locomotive behaviour and a significant decrease in the lipolytic response induced by isoproterenol on isolated adipocytes from animals treated with VC were observed. CONCLUSION This work demonstrates that an oral ascorbic acid supplementation has direct effects on behavioural activity and on adipocyte lipolysis in early obesity stages in rats, which could indicate a protective short-term role of this vitamin against adiposity induced by chronic high-fat diet consumption.
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Affiliation(s)
- D F Garcia-Diaz
- Department of Nutrition and Food Sciences, Physiology and Toxicology, University of Navarra, Pamplona, Spain
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14
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Ziylan YZ, Baltaci AK, Mogulkoc R. Leptin transport in the central nervous system. Cell Biochem Funct 2009; 27:63-70. [PMID: 19205004 DOI: 10.1002/cbf.1538] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Synthesized and released by the adipose tissue, leptin is the widely studied 167-amino acid hormonal protein product of the obesity gene. Originally leptin was defined in association with satiety and energy balance and claimed to be an anti-obesity factor that functioned via a feedback effect from adipocytes to hypothalamus. There is a growing body of evidence that emphasizes the importance of leptin in the regulation of food intake and body weight in animals and humans, alike. Other research findings point out that it plays a role in the regulation of the metabolism, sexual development, reproduction, hematopoiesis, immunity, gastrointestinal functions, sympathetic activation, and angiogenesis. The aim of this review is to evaluate the relation between leptin and the central nervous system (CNS).
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Affiliation(s)
- Yusuf Ziya Ziylan
- Department of Physiology, Istanbul Medical School, Istanbul University, Capa, Istanbul, Turkey
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15
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Alemzadeh R, Karlstad MD, Tushaus K, Buchholz M. Diazoxide enhances basal metabolic rate and fat oxidation in obese Zucker rats. Metabolism 2008; 57:1597-607. [PMID: 18940400 DOI: 10.1016/j.metabol.2008.06.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Accepted: 06/13/2008] [Indexed: 11/26/2022]
Abstract
Persistent suppression of hyperinsulinemia in genetically obese (fa/fa) Zucker rats by diazoxide (DZ) reduces food intake and weight gain; improves insulin sensitivity, glycemic control, and lipid profile; and enhances beta(3)-adrenergic function and lipolysis in adipose tissue. The aim of this study was to elucidate the effects of DZ on basal metabolic rate (BMR), fat oxidation, and adrenergic function of lean and obese Zucker rats. Diazoxide (150 mg/kg/d) or vehicle (control) was administered for 4 weeks in 7-week-old obese and lean Zucker rats (n = 8-9 per subgroup). Animals underwent indirect calorimetry, body composition analysis, and determination of uncoupling proteins (UCPs) messenger RNA (mRNA) in brown and white adipose tissues (BAT and WAT) and skeletal muscle (SM), beta(3)-adrenergic receptor (AR) mRNA in BAT and WAT, beta(2)-AR in SM as well as WAT, and SM adenylate cyclase (AC) activity at the completion of study. Diazoxide treatment decreased food intake, weight gain, and body fat in obese rats (P < .01). Although DZ treatment lowered fasting plasma glucose, insulin, leptin, adiponectin, and lipids in obese rats (P < .01), it increased adiponectin-leptin ratio (P < .01). Plasma adiponectin-leptin ratio was inversely correlated with fat mass in obese and lean rats (r = -0.86, P < .0001). Diazoxide treatment resulted in higher BMR and fat oxidation rate in obese compared with control animals (P < .01), without any effect in lean animals. Furthermore, plasma adiponectin was inversely correlated with BMR (-0.56, P < .001) and lipid oxidation rate (-0.61, P < .0005) and was positively correlated with nonprotein respiratory quotient (r = 0.41, P < .01) in obese and lean rats. This was associated with increased beta(3)-AR mRNA expression in BAT and WAT (P < .01), UCP-1 and UCP-3 in BAT and AC activity in WAT (P < .02), and AC activity in SM of DZ obese rats compared with controls (P < .01), without significant change in SM beta(2)-AR mRNA expressions. Diazoxide attenuation of hyperinsulinemia decreased the rate of weight gain but enhanced insulin sensitivity, BMR, and fat oxidation in obese rats. This was associated with increased receptor- and non-receptor-mediated adrenergic function in adipose and muscle tissues in obese rats, respectively. These metabolic changes in obese Zucker rats suggest that antiobesity effects of DZ appear to be not only through its anorectic effect, modification of disturbed insulin metabolism, and inhibition of lipogenesis, but also due to augmentation of adrenergic function, energy expenditure, and fat utilization.
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Affiliation(s)
- Ramin Alemzadeh
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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16
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Bielinski SJ, Pankow JS, Boerwinkle E, Bray MS, Kao WHL, Folsom AR. Lack of association between uncoupling protein-2 Ala55Val polymorphism and incident diabetes in the atherosclerosis risk in communities study. Acta Diabetol 2008; 45:179-82. [PMID: 18496642 PMCID: PMC2586599 DOI: 10.1007/s00592-008-0039-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Accepted: 04/14/2008] [Indexed: 11/30/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is characterized by impaired insulin secretion, peripheral insulin resistance, and increased hepatic glucose production. Genes that contribute to genetic susceptibility to T2DM function in numerous biochemical pathways. Uncoupling protein-2 (UCP2) functions as a negative regulator of insulin secretion. Animal studies show induction of UCP2 plays a pathogenic role in the progression of obesity-induced T2DM and some human studies have shown an association between a common UCP2 polymorphism, Ala55Val (rs660339), and T2DM, obesity, and resting metabolic rate with the Val/Val genotype conferring increased risk. We investigated the relationship between the Ala55Val variant and incidence of T2DM among 12,056 participants in the Atherosclerosis Risk in Communities (ARIC) Study aged 45-64 years at baseline. Incident T2DM (n = 1,406) cases were identified over 9 years of follow-up. The Val55 allele frequency was 44% in blacks and 41% in whites. The rate of T2DM per 1,000 person was 15.0, 15.6, and 15.6 yearsfor Ala/Ala, Ala/Val, and Val/Val genotypes, respectively. We found no significant association between UCP2 genotypes and incident T2DM in the whole cohort, in race-gender subgroups, or in categories of body mass index (normal, overweight and obese). The Ala55Val polymorphism of UCP2 was not associated with incident T2DM in the ARIC cohort.
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Affiliation(s)
- Suzette J Bielinski
- Division of Epidemiology and Community Health, University of Minnesota, 1300 South 2nd Street, Suite 300, Minneapolis, MN 55454, USA.
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17
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García-Díaz D, Campión J, Milagro FI, Martínez JA. Adiposity dependent apelin gene expression: relationships with oxidative and inflammation markers. Mol Cell Biochem 2007; 305:87-94. [PMID: 17594060 DOI: 10.1007/s11010-007-9531-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2007] [Accepted: 06/08/2007] [Indexed: 10/23/2022]
Abstract
It has been reported that apelin functions as an adipokine, which has been associated to obesity and insulin resistance. The objective of this study was to analyze the apelin mRNA expression in white adipose tissue (WAT) from high-fat (Cafeteria) fed rats, in order to examine potential relationships with obesity markers and other related risk factors. Animals fed on the high-fat diet during 56 days increased their body weight, total body fat and WAT depots weights when compared to controls. Apelin subcutaneous mRNA expression was higher in the Cafeteria than in the Control fed group and this increase was partially reversed by dietary vitamin C supplementation. Statistically significant associations between subcutaneous apelin gene expression and almost all the studied variables were identified, being of special interest the correlations found with serum leptin (r=0.517), liver malondialdehyde (MDA) levels (r=0.477), and leptin, IRS-3 and IL-1ra retroperitoneal mRNA expression (r=0.701; r=0.692 and r=0.561, respectively). These associations evidence a possible role for apelin in the excessive weight gain induced by high-fat feeding and increased adiposity, insulin-resistance, liver oxidative stress and inflammation.
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Affiliation(s)
- Diego García-Díaz
- Department of Physiology and Nutrition, University of Navarra, C/Irunlarrea s/n, 31008, Pamplona, Spain
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18
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Pérez-Matute P, Pérez-Echarri N, Martínez JA, Marti A, Moreno-Aliaga MJ. Eicosapentaenoic acid actions on adiposity and insulin resistance in control and high-fat-fed rats: role of apoptosis, adiponectin and tumour necrosis factor-alpha. Br J Nutr 2007; 97:389-98. [PMID: 17298710 DOI: 10.1017/s0007114507207627] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
n-3 PUFA have shown potential anti-obesity and insulin-sensitising properties. However, the mechanisms involved are not clearly established. The aim of the present study was to assess the effects of EPA administration, one of the n-3 PUFA, on body-weight gain and adiposity in rats fed on a standard or a high-fat (cafeteria) diet. The actions on white adipose tissue lipolysis, apoptosis and on several genes related to obesity and insulin resistance were also studied. Control and cafeteria-induced overweight male Wistar rats were assigned into two subgroups, one of them daily received EPA ethyl ester (1 g/kg) for 5 weeks by oral administration. The high-fat diet induced a very significant increase in both body weight and fat mass. Rats fed with the cafeteria diet and orally treated with EPA showed a marginally lower body-weight gain (P = 0.09), a decrease in food intake (P < 0.01) and an increase in leptin production (P < 0.05). EPA administration reduced retroperitoneal adipose tissue weight (P < 0.05) which could be secondary to the inhibition of the adipogenic transcription factor PPARgamma gene expression (P < 0.001), and also to the increase in apoptosis (P < 0.05) found in rats fed with a control diet. TNFalpha gene expression was significantly increased (P < 0.05) by the cafeteria diet, while EPA treatment was able to prevent (P < 0.01) the rise in this inflammatory cytokine. Adiposity-corrected adiponectin plasma levels were increased by EPA. These actions on both TNFalpha and adiponectin could explain the beneficial effects of EPA on insulin resistance induced by the cafeteria diet.
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Affiliation(s)
- Patricia Pérez-Matute
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain
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19
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Rosado EL, Bressan J, Martins MF, Cecon PR, Martínez JA. Polymorphism in the PPARgamma2 and beta2-adrenergic genes and diet lipid effects on body composition, energy expenditure and eating behavior of obese women. Appetite 2007; 49:635-43. [PMID: 17658197 DOI: 10.1016/j.appet.2007.04.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2006] [Revised: 04/10/2007] [Accepted: 04/12/2007] [Indexed: 12/21/2022]
Abstract
In order to evaluate the effect of polymorphism in the PPARgamma2 and beta2-adrenergic genes and diet lipids on body composition, energy expenditure and eating behavior of obese women, 60 subjects were submitted to anthropometric, biochemical, dietary, molecular, basal and postprandial metabolism (indirect calorimetry) and eating behavior (visual analog scale) evaluation. Fat and saturated fatty acid (SFA) high diet was used to assess postprandial metabolism. The frequency of Pro12Pro/Gln27Gln, Pro12Pro/Gln27Glu, Pro12Pro/Glu27Glu and Pro12Ala/Gln27Glu genotypes was 35.71%, 30.37%, 23.21% and 10.71%, respectively. These values were not significant (p>0.05) for the dietary, anthropometric, biochemical and metabolic parameters. The Pro12Ala/Gln27Glu group was found to present greater energy used in postprandial period (EUPP). The presence of the PPARgamma2 gene variant, independent of beta2-adrenergic gene polymorphism, resulted in fat oxidation increase. Also, this group presented higher satiety, compared to the Pro12Pro/Gln27Gln group. The presence of the variant alleles in the PPARgamma2 gene suggests benefits in food intake control.
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Affiliation(s)
- Eliane Lopes Rosado
- Departamento de Nutrição e Dietética, Instituto de Nutrição, Universidade Federal do Rio de Janeiro, Avenida Brigadeiro Trompowski S/N, Cidade Universitária, Ilha do Fundão, Rio de Janeiro RJ 21941-590, Brazil.
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20
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Ramsay TG, Richards MP. Beta-adrenergic regulation of uncoupling protein expression in swine. Comp Biochem Physiol A Mol Integr Physiol 2007; 147:395-403. [PMID: 17383207 DOI: 10.1016/j.cbpa.2007.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2006] [Revised: 01/11/2007] [Accepted: 01/11/2007] [Indexed: 11/28/2022]
Abstract
This study examined the beta-adrenergic regulation of uncoupling protein (UCP) 2 and UCP3 gene expression in porcine tissues. In vitro experiments examined changes in UCP2 and UCP3 gene expression in middle (MSQ) and outer (OSQ) subcutaneous adipose tissues from crossbred neutered male pigs. Incubation of tissue slices (24 h) with 0 to 1000 nM isoproterenol increased UCP2 and UCP3 mRNA abundance in MSQ and OSQ, relative to 18S rRNA (P<0.05). For the in vivo experiment, nine randomly selected pigs (80 kg) were presented with a diet supplemented with 10.0 ppm ractopamine for 2 weeks. Another eight pigs were maintained on a control diet. Dietary ractopamine did not affect adipose UCP2 or UCP3 gene expression (P>0.05). However, UCP2 mRNA abundance was depressed in semitendinosus white (STW, P<0.05) and semitendinosus red (STR, P<0.001) by ractopamine feeding. Also, ractopamine decreased UCP3 mRNA abundance by 28% in STW (P<0.05). The in vitro data suggest that beta-adrenergic agonists directly affect adipose tissue UCP expression, although these adipose effects can be masked by the in vivo physiology. The in vivo data indicate that beta-adrenergic agonists may function in regulating UCP2 and UCP3 expression in selected muscles.
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Affiliation(s)
- T G Ramsay
- Growth Biology Laboratory, USDA-ARS, Beltsville, MD 20705, USA.
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21
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Pearen MA, Ryall JG, Maxwell MA, Ohkura N, Lynch GS, Muscat GEO. The orphan nuclear receptor, NOR-1, is a target of beta-adrenergic signaling in skeletal muscle. Endocrinology 2006; 147:5217-27. [PMID: 16901967 DOI: 10.1210/en.2006-0447] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
beta-Adrenergic receptor (beta-AR) agonists induce Nur77 mRNA expression in the C2C12 skeletal muscle cell culture model and elicit skeletal muscle hypertrophy. We previously demonstrated that Nur77 (NR4A1) is involved in lipolysis and gene expression associated with the regulation of lipid homeostasis. Subsequently it was demonstrated by another group that beta-AR agonists and cold exposure-induced Nur77 expression in brown adipocytes and brown adipose tissue, respectively. Moreover, NOR-1 (NR4A3) was hyperinduced by cold exposure in the nur77(-/-) animal model. These studies underscored the importance of understanding the role of NOR-1 in skeletal muscle. In this context we observed 30-480 min of beta-AR agonist treatment significantly and transiently increased expression of the orphan nuclear receptor NOR-1 in both mouse skeletal muscle tissue (plantaris) and C2C12 skeletal muscle cells. Specific beta(2)- and beta(3)-AR agonists had similar effects as the pan-agonist and were blocked by the beta-AR antagonist propranolol. Moreover, in agreement with these observations, isoprenaline also significantly increased the activity of the NOR-1 promoter. Stable exogenous expression of a NOR-1 small interfering RNA (but not the negative control small interfering RNA) in skeletal muscle cells significantly repressed endogenous NOR-1 mRNA expression and led to changes in the expression of genes involved in the control of lipid use and muscle mass underscored by a dramatic increase in myostatin mRNA expression. Concordantly the myostatin promoter was repressed by NOR-1 expression. In conclusion, NOR-1 is highly responsive to beta-adrenergic signaling and regulates the expression of genes controlling fatty acid use and muscle mass.
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MESH Headings
- Animals
- Cell Differentiation
- Cells, Cultured
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/physiology
- Homeostasis
- Ion Channels/physiology
- Isoproterenol/pharmacology
- Lipid Metabolism
- Mice
- Mitochondrial Proteins/physiology
- Muscle Development
- Muscle, Skeletal/cytology
- Muscle, Skeletal/metabolism
- Myostatin
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/physiology
- Nuclear Receptor Subfamily 4, Group A, Member 1
- Promoter Regions, Genetic
- RNA, Messenger/analysis
- RNA, Small Interfering/pharmacology
- Receptors, Adrenergic, beta/physiology
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Steroid/genetics
- Receptors, Steroid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Signal Transduction/physiology
- Transcription Factors/physiology
- Transforming Growth Factor beta/genetics
- Uncoupling Protein 2
- Uncoupling Protein 3
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Affiliation(s)
- Michael A Pearen
- Institute for Molecular Bioscience, Division of Molecular Genetics and Development, University of Queensland, St. Lucia, Queensland 4072, Australia
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22
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Brito PD, Ramos CF, Passos MCF, Moura EG. Adaptive changes in thyroid function of female rats fed a high-fat and low-protein diet during gestation and lactation. Braz J Med Biol Res 2006; 39:809-16. [PMID: 16751988 DOI: 10.1590/s0100-879x2006000600015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The percent of lipids in the western diet has been continuously increasing in the last decades and is associated with a decrease in the proportion of protein intake. Recently, we demonstrated that protein malnutrition during lactation is associated with lower body weight and thyroid hypofunction in female rats and their offspring. Our objective in the present study was to determine if a high-fat and low-protein diet was associated with similar changes. Three-month-old female Wistar rats were randomly assigned to one of the following groups with 8 animals each: high-fat and low-protein (40% lipid, 5% protein, and 55% carbohydrate of the total energy content) from the 3rd week of gestation to the end of lactation; control group--standard diet (11% lipid, 23% protein, and 66% carbohydrate of the total energy content). Food consumption and body weight were monitored daily. Serum thyrotropin and thyroid hormone concentrations were determined by specific radioimmunoassay at the end of lactation. Animals receiving high-fat and low-protein diet had a significantly lower body weight (13.9% at weaning, P < 0.05) and serum albumin (25%, P < 0.05) and thyrotropin (26.2%, P < 0.01) concentrations, and a higher serum triiodothyronine concentration (74%, P < 0.005) and 131I-thyroid uptake (77%, P < 0.005). These data show that a high-fat and low-protein diet can promote maternal thyroid hyperfunction that differs from the thyroid hypofunction observed in dams fed a low-protein diet, a phenomenon that can be of adaptive importance for pup nurturing.
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Affiliation(s)
- P D Brito
- Departamento de Ciências Fisiológicas, Instituto de Biologia, Universidade do Estado do Rio de Janeiro, RJ, Brasil
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23
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Kim H, Pennisi PA, Gavrilova O, Pack S, Jou W, Setser-Portas J, East-Palmer J, Tang Y, Manganiello VC, Leroith D. Effect of adipocyte beta3-adrenergic receptor activation on the type 2 diabetic MKR mice. Am J Physiol Endocrinol Metab 2006; 290:E1227-36. [PMID: 16682489 DOI: 10.1152/ajpendo.00344.2005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The antiobesity and antidiabetic effects of the beta3-adrenergic agonists were investigated on nonobese type 2 diabetic MKR mice after injection with a beta3-adrenergic agonist, CL-316243. An intact response to acute CL-316243 treatment was observed in MKR mice. Chronic intraperitoneal CL-316243 treatment of MKR mice reduced blood glucose and serum insulin levels. Hyperinsulinemic euglycemic clamps exhibited improvement of the whole body insulin sensitivity and glucose homeostasis concurrently with enhanced insulin action in liver and adipose tissue. Treating MKR mice with CL-316243 significantly lowered serum and hepatic lipid levels, in part due to increased whole body triglyceride clearance and fatty acid oxidation in adipocytes. A significant reduction in total body fat content and epididymal fat weight was observed along with enhanced metabolic rate in both wild-type and MKR mice after treatment. These data demonstrate that beta3-adrenergic activation improves the diabetic state of nonobese diabetic MKR mice by potentiation of free fatty acid oxidation by adipose tissue, suggesting a potential therapeutic role for beta3-adrenergic agonists in nonobese diabetic subjects.
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Affiliation(s)
- Hyunsook Kim
- Diabetes Branch, National Institute of Diabetes, Digestive and Kidney Diseases, NIH, Bethesda, MD, USA
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24
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Irigaray P, Ogier V, Jacquenet S, Notet V, Sibille P, Méjean L, Bihain BE, Yen FT. Benzo[a]pyrene impairs beta-adrenergic stimulation of adipose tissue lipolysis and causes weight gain in mice. A novel molecular mechanism of toxicity for a common food pollutant. FEBS J 2006; 273:1362-72. [PMID: 16689925 DOI: 10.1111/j.1742-4658.2006.05159.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Benzo[a]pyrene (B[a]P) is a common food pollutant that causes DNA adduct formation and is carcinogenic. The report of a positive correlation between human plasma B[a]P levels and body mass index, together with B[a]P's lipophilicity, led us to test for possible adverse effects of B[a]P on adipose tissue. In ex vivo experiments using primary murine adipocytes, B[a]P rapidly (within minutes) and directly inhibited epinephrine-induced lipolysis (up to 75%) in a dose-dependent manner. Half-maximum inhibition was obtained with a B[a]P concentration of 0.9 mg.L(-1) (3.5 microm). Lipolysis induced by beta(1)-, beta(2)- and beta(3)-adrenoreceptor-specific agonists, as well as ACTH, were also significantly inhibited by B[a]P, whereas forskolin-induced lipolysis was not B[a]P-sensitive. Similar inhibition of catecholamine-induced lipolysis by B[a]P was also seen in isolated human adipocytes; half-maximum inhibition of lipolysis was achieved with a B[a]P concentration of 0.02 mg.L(-1) (0.08 microm). In vivo treatment of C57Bl/6J mice with 0.4 mg.kg(-1) B[a]P inhibited epinephrine-induced release of free fatty acids by 70%. Chronic exposure of mice to B[a]P (0.5 mg.kg(-1) injected i.p. every 48 h) for 15 days also decreased lipolytic response to epinephrine and induced a 43% higher weight gain compared with controls (B[a]P: 2.23 +/- 0.12 g versus control: 1.56 +/- 0.18 g, P < 0.01) due to increased fat mass. The weight gain occurred consistently without detectable changes in food intake. These results reveal a novel molecular mechanism of toxicity for the environmental pollutant B[a]P and introduce the notion that chronic exposure of human population to B[a]P and possibly other polycyclic aromatic hydrocarbons could have an impact on metabolic disorders, such as obesity.
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Affiliation(s)
- Philippe Irigaray
- JE2482 Lipidomix, Institut National Polytechnique de Lorraine, Vandoeuvre-lès-Nancy, France
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25
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Pérez-Echarri N, Pérez-Matute P, Martínez JA, Marti A, Moreno-Aliaga MJ. Serum and gene expression levels of leptin and adiponectin in rats susceptible or resistant to diet-induced obesity. J Physiol Biochem 2005; 61:333-42. [PMID: 16180331 DOI: 10.1007/bf03167050] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The aim of the present study was to identify the role of leptin and adiponectin in the development of resistance or susceptibility to diet-induced obesity in rats. For this purpose, male Wistar rats were fed with standard laboratory diet (control group) or cafeteria diet. After 15 days, two groups of rats with different response respect to the cafeteria diet were identified, and were assigned as diet-induced obesity (DIO) and diet resistant (DR) rats. The high-fat diet induced a very significant increase in both body and fat mass weight in DIO group. However, DR rats, gained even less weight than control-fed animals. Food intake was increased in cafeteria-fed rats (both DIO and DR) in comparison to control group; but hyperphagia was higher in DIO rats. In addition, feed efficiency (the ratio of weight gained to calories consumed) was significantly decreased in DR as compared to DIO rats. Regarding leptin, a significant increase in both adipose tissue gene expression and serum levels was observed in DIO rats in comparison with other groups (control and DR). A significant increase in both adiponectin circulating levels and adipose tissue mRNA expression was also observed in DIO animals as compared with the other groups. These data suggest that the susceptibility to obesity of DIO rats might be secondary, at least in part, to an earlier development of leptin resistance, which could lead to alterations in food intake (hyperphagia) and energetic metabolism. However, neither changes in leptin or adiponectin seem to be involved in the adaptive mechanisms that confer resistance to high fat intake.
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Affiliation(s)
- N Pérez-Echarri
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain
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26
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Delage B, Bairras C, Buaud B, Pallet V, Cassand P. A high-fat diet generates alterations in nuclear receptor expression: prevention by vitamin A and links with cyclooxygenase-2 and beta-catenin. Int J Cancer 2005; 116:839-46. [PMID: 15856452 DOI: 10.1002/ijc.21108] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Epidemiologic studies suggest that intake of high energy from fat, inducing overweight, increases the risk of cancer development and promotes colon carcinogenesis. It is therefore important to understand which parameters are affected early on by a high-fat diet in order to devise and improve protective nutritional strategies. We investigated the effect of high energy/fat intake on colon mucosa of male Wistar rats induced by a single 1,2-dimethylhydrazine (DMH) injection. Aberrant crypt foci (ACF) were numbered and modifications in cyclooxygenase-2 (COX-2) and beta-catenin levels assessed. Peroxisome proliferator- and retinoic acid-activated receptors (PPAR and RAR, RXR) are key transcription factors regulating gene expression in response to nutrient-activated signals. A short-term study was designed to evaluate whether alterations in mRNA expression of nuclear receptors can be detected at the beginning of the weight gain phase induced by an appetizing hyperlipidic diet (HLD). HLD consumption induced early downregulation of PPARgamma (-33.1%) and RARbeta (-53.1%) mRNA expression concomitant with an increase in levels of COX-2 (+45.5%) and beta-catenin (+84.56%) and in the number of ACF (191.56 +/- 88.60 vs. 21.14 +/- 11.64, p < 0.05). These findings suggest that HLD increases ACF occurrence, possibly through alterations in the mRNA expression profile of nuclear receptors. Moreover, the use HLD rich in retinyl esters or supplemented with all-trans retinoic acid led to a reduction in the number of ACF. Vitamin A also prevented HLD-induced alterations and the increase in levels of COX-2 and beta-catenin. The present observations show a protective role for vitamin A against disturbances associated with HLD exposure in induced colon carcinogenesis.
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Affiliation(s)
- Barbara Delage
- Laboratory of Food and Colon Carcinogenesis, Unit of Nutrition and Cellular Signalling, University Bordeaux 1, Talence, France.
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Lamas O, Martínez JA, Marti A. Energy restriction restores the impaired immune response in overweight (cafeteria) rats. J Nutr Biochem 2004; 15:418-25. [PMID: 15219927 DOI: 10.1016/j.jnutbio.2004.02.003] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2003] [Indexed: 10/26/2022]
Abstract
Impaired immune function linked to obesity has been shown in both human and animal studies. The purpose of this work was to evaluate the effects of a 4-week energy restriction (50% of total energy intake) on immune function in previously diet-induced (cafeteria) overweight rats. Flow cytometric analysis revealed that the number of spleen T helper cells were significantly (P < 0.05) elevated in control and overweight energy-restricted rats as compared with groups fed ad libitum groups. The proliferative response of splenocytes to phytohaemaglutinin and concanavalin A from overweight rats after energy restriction was significantly (P < 0.05) higher compared to overweight nonrestricted rats. The cytotoxic activity of natural killer cells tended to be lower in overweight rats compared to controls. Finally, control rats under the dietary deprivation period presented higher levels of uncoupling protein 2 mRNA and lower levels of leptin receptor mRNA compared with the reference control group. These results suggest that energy restriction is able to restore, at least in part, the impaired immune response commonly observed in overweight animals.
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Affiliation(s)
- Oscar Lamas
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain
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28
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López IP, Milagro FI, Martí A, Moreno-Aliaga MJ, Martínez JA, De Miguel C. Gene expression changes in rat white adipose tissue after a high-fat diet determined by differential display. Biochem Biophys Res Commun 2004; 318:234-9. [PMID: 15110778 DOI: 10.1016/j.bbrc.2004.04.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Indexed: 12/12/2022]
Abstract
The differences in gene expression pattern of visceral white adipose tissue between control and high-fat-fed rats were compared using the mRNA differential display methodology. The results, confirmed by Northern blot, showed eight genes upregulated: adiponectin, fibrillin-1, transferrin, Y-box binding protein-1, IgE receptor beta chain (FcRIbeta), alpha-1 haemoglobin, and ribosomal proteins S10 and L7 and four genes downregulated: caveolin-2, lactate dehydrogenase-A, mitochondrial 16S rRNA, and mitochondrial cytochrome oxidase subunit I/serine tRNA. Two of these genes have been already related to obesity (adiponectin and caveolin-2) while the others are known to participate in metabolic, signalling or transcription regulation pathways that can be relevant in energy (lipid and/or carbohydrate) metabolism.
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Affiliation(s)
- I P López
- Department of Biochemistry and Molecular Biology, University of Navarra, 31080 Pamplona, Navarra, Spain
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29
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Lamas O, Martínez JA, Marti A. Effects of a beta3-adrenergic agonist on the immune response in diet-induced (cafeteria) obese animals. J Physiol Biochem 2004; 59:183-91. [PMID: 15000449 DOI: 10.1007/bf03179914] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Molecules with affinity for beta3-adrenoceptors are not only effective anti-obesity agents in rodent models, but may play a role in the regulation of the immune response. The aim of the current investigation was to analyse the effects of trecadrine on the immune response in diet-induced (cafeteria) obese rats. Male Wistar rats were divided into 2 groups, the control group (C, n=9) was fed with the standard pelleted chow laboratory diet, while the other group was fed with a high-fat (cafeteria) diet. Cafeteria-fed rats were divided into two new subgroups (n=9 each), which received either i.p. saline (obese, O) or trecadrine (1mg/kg/day) (obese+trecadrine, O+T) daily for 5 weeks. Lymphocyte subpopulations and the proliferative response were determined by validated procedures. The administration of trecadrine was able to prevent the onset of obesity in cafeteria-fed rats. Trecadrine-treatment to obese animals appeared to improve the number of lymphocyte subpopulations (CD4+ and CD8+) as compared to those animals only receiving the high-fat diet, being the values of the trecadrine-treated animals on the high-fat diet similar to the control rats. However, the lymphoproliferative response when stimulated with several mitogens was markedly reduced by the cafeteria intake and was further decreased by the beta3-adrenergic administration. The spleen mRNA expression level of UCP2, PPARgamma and Ob-Rb were not affected by the trecadrine treatment. Summing up, at the immune system level, trecadrine administration increased the proportion of CD4+ spleen lymphocytes, although it was not able to restore the lymphocyte proliferative response which was depressed.
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Affiliation(s)
- O Lamas
- Dept. of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain
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30
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Lamas O, Moreno-Aliaga MJ, Martinez JA, Marti A. NF-kappa B-binding activity in an animal diet-induced overweightness model and the impact of subsequent energy restriction. Biochem Biophys Res Commun 2004; 311:533-9. [PMID: 14592449 DOI: 10.1016/j.bbrc.2003.10.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
An impaired immune function linked to obesity has been shown in both human and animal studies. The purpose of this work was to analyse the hypothesis that PPAR gamma 1 participates in the inhibition of the immune response by affecting the DNA-binding ability of the NF-kappa B complex and whether the SREBP-1 expression can regulate PPAR gamma 1 expression in spleen. Diet-induced overweight rats showed higher PPAR gamma 1 (p<0.05) and lower SREBP-1 (p<0.01) mRNA expression levels with an inhibition of the DNA-binding ability of NF-kappa B compared to control rats as determined by gel-shift analysis. On the other hand, energy restriction decreased SREBP-1 (p<0.01) mRNA expression with no differences in PPAR gamma 1 mRNA expression compared to non-restricted rats, which was accompanied by a restoration in the DNA-binding ability of NF-kappa B as shown by gel-shift analysis. These results suggest that PPAR gamma 1 may be involved in the altered immune response through changes in the activity of NF-kappa B.
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Affiliation(s)
- O Lamas
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Navarre, Spain
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31
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Moore MC, Cardin S, Edgerton DS, Farmer B, Neal DW, Lautz M, Cherrington AD. Unlike mice, dogs exhibit effective glucoregulation during low-dose portal and peripheral glucose infusion. Am J Physiol Endocrinol Metab 2004; 286:E226-33. [PMID: 14519598 DOI: 10.1152/ajpendo.00343.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Portal infusion of glucose in the mouse at a rate equivalent to basal endogenous glucose production causes hypoglycemia, whereas peripheral infusion at the same rate causes significant hyperglycemia. We used tracer and arteriovenous difference techniques in conscious 42-h-fasted dogs to determine their response to the same treatments. The studies consisted of three periods: equilibration (100 min), basal (40 min), and experimental (180 min), during which glucose was infused at 13.7 micromol.kg(-1).min(-1) into a peripheral vein (p.e., n = 5) or the hepatic portal (p.o., n = 5) vein. Arterial blood glucose increased approximately 0.8 mmol/l in both groups. Arterial and hepatic sinusoidal insulin concentrations were not significantly different between groups. p.e. exhibited an increase in nonhepatic glucose uptake (non-HGU; Delta8.6 +/- 1.2 micromol.kg(-1).min(-1)) within 30 min, whereas p.o. showed a slight suppression (Delta-3.7 +/- 3.1 micromol.kg(-1).min(-1)). p.o. shifted from net hepatic glucose output (NHGO) to uptake (NHGU; 2.5 +/- 2.8 micromol.kg-1.min-1) within 30 min, but p.e. still exhibited NHGO (6.0 +/- 1.9 micromol.kg(-1).min(-1)) at that time and did not initiate NHGU until after 90 min. Glucose rates of appearance and disappearance did not differ between groups. The response to the two infusion routes was markedly different. Peripheral infusion caused a rapid enhancement of non-HGU, whereas portal delivery quickly activated NHGU. As a result, both groups maintained near-euglycemia. The dog glucoregulates more rigorously than the mouse in response to both portal and peripheral glucose delivery.
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Affiliation(s)
- Mary Courtney Moore
- Department of Molecular Physiology and Biophysics,Vanderbilt University School of Medicine, Nashville, Tennessee 37232-0615, USA.
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Hu B, Jennings LL. Orally bioavailable beta 3-adrenergic receptor agonists as potential therapeutic agents for obesity and type-II diabetes. PROGRESS IN MEDICINAL CHEMISTRY 2003; 41:167-94. [PMID: 12774694 DOI: 10.1016/s0079-6468(02)41005-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Affiliation(s)
- Baihua Hu
- Wyeth Research, P.O. Box 42528, Philadelphia, PA 19101, USA
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33
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López IP, Marti A, Milagro FI, Zulet Md MDLA, Moreno-Aliaga MJ, Martinez JA, De Miguel C. DNA microarray analysis of genes differentially expressed in diet-induced (cafeteria) obese rats. OBESITY RESEARCH 2003; 11:188-94. [PMID: 12582213 DOI: 10.1038/oby.2003.30] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To better understand the molecular basis of dietary obesity, we examined adipose tissue genes differentially expressed in an obesity model using DNA microarray analysis. RESEARCH METHODS AND PROCEDURES We assessed the expression level of over 12,500 transcripts in epididymal fat pads from (cafeteria) obese and control rats with the aid of the array technology. RESULTS Cafeteria (obese) rats weighed 50% more and had 2.5-fold higher levels of epididymal fat and elevated levels of circulating leptin. Adipose genes differentially expressed in obese and control rats were categorized into five groups: macronutrient metabolism, transcription factors, hormone receptor and signal transduction, redox and stress proteins, and cellular cytoskeleton. Interestingly, the expression levels of a number of genes involved in lipid metabolism such as glycerol-3-phosphate dehydrogenase, stearoyl coenzyme A desaturase, together with the transcription factors implicated in adipocyte differentiation (CAAT/enhancer binding protein-alpha and peroxisome proliferator-activated receptor-gamma), were significantly increased in obese animals compared with control. The most up-regulated transcripts were the ob (49.2-fold change) and the fatty acid-binding protein genes (15.7- fold change). In contrast, genes related to redox and stress protein were generally down-regulated in obese animals compared with the control. DISCUSSION Our study showed that in diet-induced obesity, the expression levels of some important genes implicated in lipid metabolism were up-regulated, whereas those related to redox and stress protein were down-regulated in obese animals compared with control. This pattern of gene expression may occur in human obesity cases after high-fat intake.
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Affiliation(s)
- Iciar P López
- Department of Biochemistry, University of Navarro, 31080 Pamplona, Navarra, Spain
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Moreno-Aliaga MJ, Martínez JA, Stanhope KL, Fernández-Otero MP, Havel PJ. Effects of Trecadrine, a beta3-adrenergic agonist, on leptin secretion, glucose and lipid metabolism in isolated rat adipocytes. Int J Obes (Lond) 2002; 26:912-9. [PMID: 12080443 DOI: 10.1038/sj.ijo.0802003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2001] [Revised: 01/03/2002] [Accepted: 01/08/2002] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Leptin, a hormone produced in adipocytes, is a key signal in the regulation of food intake and energy expenditure. Beta-adrenergic agonists have been shown to inhibit leptin gene expression and leptin secretion. The mechanisms underlying the inhibitory effects of beta-adrenergic agonists have not been established. In this study, we examined the effects of Trecadrine, a novel beta3-adrenergic agonist, on basal and insulin-stimulated leptin secretion in isolated rat adipocytes. Because insulin-stimulated glucose metabolism is an important regulator of leptin expression and secretion by the adipocytes, the effects of Trecadrine on indices of adipocyte metabolism were also examined. MEASUREMENTS Isolated adipocytes were incubated with Trecadrine (10(-8)-10(-4) M) in the absence or presence of insulin (1.6 nM). Leptin secretion, glucose utilization, lactate production, glucose incorporation into CO(2) and triglyceride, as well as lipolysis (glycerol release) were determined. RESULTS Trecadrine induced a concentration-dependent inhibition of basal leptin secretion. Trecadrine also decreased insulin-stimulated leptin secretion; however, the effect was not as pronounced as in the absence of insulin. Treatment of adipocytes with Trecadrine increased basal glucose utilization and produced a further increase in insulin-stimulated glucose utilization. Basal lactate production was also increased by Trecadrine; however, the proportion (percentage) of glucose carbon released as lactate was unaffected. In the presence of insulin, absolute lactate production was unaffected by Trecadrine at 96 h. However, the percentage of glucose carbon released as lactate was significantly decreased by insulin treatment, and was further decreased by the co-treatment with Trecadrine. Trecadrine induced a dose-dependent increase of the absolute amount of glucose incorporated into triglyceride. However, the percentage of glucose utilized that was incorporated into triglyceride was unaffected by Trecadrine. Trecadrine did not modify the proportion of glucose utilized that was oxidized to CO(2). Trecadrine increased glycerol release after 96 h of treatment. Glycerol release was negatively correlated with leptin secretion. CONCLUSIONS These results suggest that alterations of glucose metabolism are not directly involved in the effects of beta3-adrenergic agonists to inhibit leptin expression and secretion. The inverse relationship between leptin secretion and the increase of glycerol levels, which is an index of the activation of cAMP-dependent protein kinases, suggests that activation of the cAMP signaling pathway mediates the inhibitory effects of Trecadrine on leptin gene expression and secretion.
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Affiliation(s)
- M J Moreno-Aliaga
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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Abstract
The high incidence of obesity, its multifactorial nature, the complexity and lack of knowledge of the bodyweight control system, and the scarcity of adequate therapeutics have fuelled anti-obesity drug development during a considerable number of years. Irrespective of the efforts invested by researchers and companies, few products have reached a minimum level of effectiveness, and even fewer are available in medical practice. As a consequence of anti-obesity research, our knowledge of the bodyweight control system increased but, despite this, the pharmacological approaches to the treatment of obesity have not resulted yet in effective drugs. This review provides a panoramic of the multiple different approaches developed to obtain workable drugs. These approaches, however, rely in only four main lines of action: control of energy intake, mainly through modification of appetite;control of energy expenditure, essentially through the increase of thermogenesis;control of the availability of substrates to cells and tissues through hormonal and other metabolic factors controlling the fate of the available energy substrates; andcontrol of fat reserves through modulation of lipogenesis and lipolysis in white adipose tissue. A large proportion of current research is centred on neuropeptidic control of appetite, followed by the development of drugs controlling thermogenic mechanisms and analysis of the factors controlling adipocyte growth and fat storage. The adipocyte is also a fundamental source of metabolic signals, signals that can be intercepted, modulated and used to force the brain to adjust the mass of fat with the physiological means available. The large variety of different approaches used in the search for effective anti-obesity drugs show both the deep involvement of researchers on this field and the large amount of resources devoted to this problem by pharmaceutical companies. Future trends in anti-obesity drug research follow closely the approaches outlined; however, the increasing mass of information on the molecular basis of bodyweight control and obesity will in the end prevail in our search for effective and harmless anti-obesity drugs.
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Affiliation(s)
- José-Antonio Fernández-López
- Centre Especial de Recerca en Nutrició i Ciència dels Aliments, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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36
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Marti A, Vaquerizo J, Zulet MA, Moreno-Aliaga MJ, Martínez JA. Down-regulation of heart HFABP and UCP2 gene expression in diet-induced (cafeteria) obese rats. J Physiol Biochem 2002; 58:69-74. [PMID: 12435081 DOI: 10.1007/bf03179841] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Long-term exposure to hypercaloric high fat diet induced marked tissue fatty acid accumulation and may influence cell function. Previous results in our laboratory showed that uncoupling proteins (UCPs) and fatty acid-binding protein (FABP) gene expression are changed in adipose tissue and skeletal muscle tissue in diet-induced (cafeteria) obese animals. The aim of this study was to examine heart FABP (HFABP) and UCP2 gene expressions in dietary obese rats. Rats fed on a high-fat diet for 65 days had significantly higher fat stores and body weight than control rats. Interestingly, we found that both HFABP and UCP2 mRNA levels were significantly reduced in cafeteria-obese rats when compared to control animals. Moreover, a statistically significant correlation was observed between the two gene expression levels. The down-regulation of heart HFABP and UCP2 parallels the lower lipid utilization which may account for an enhanced fat deposition. It is plausible that these two genes are regulated by the same family of transcription factors.
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Affiliation(s)
- A Marti
- Dpto de Fisiología y Nutrición, Universidad de Navarra, Pamplona, Spain.
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Lamas O, Martinez J, Marti A. T-helper lymphopenia and decreased mitogenic response in cafeteria diet-induced obese rats. Nutr Res 2002. [DOI: 10.1016/s0271-5317(02)00362-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Moreno-Aliaga MJ, Lamas O, Marti A, Martínez JA. Effects of a beta3-adrenergic agonist on glucose uptake and leptin expression and secretion in cultured adipocytes from lean and overweight (cafeteria) rats. Biochem Biophys Res Commun 2002; 291:1201-7. [PMID: 11883944 DOI: 10.1006/bbrc.2002.6577] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The increase in body and white adipose tissue weights induced by a high-fat diet were prevented by treatment with the beta3-adrenergic agonist Trecadrine. Plasma insulin levels were slightly elevated in overweight rats, while a decrease was observed in Trecadrine-treated groups. Insulin-dependent glucose uptake was impaired in adipocytes of the overweight rats in relation to lean animals. The beta3-adrenergic agonist induced an increase in insulin-stimulated glucose uptake by adipocytes as compared to the nontreated animals. In fact, Trecadrine treatment was able to restore to control values the impairment in insulin-mediated glucose uptake induced by the cafeteria diet, suggesting that Trecadrine prevents the development of insulin resistance in overweight animals. Basal leptin secretion was increased in adipocytes of the overweight rats in relation to lean animals. Trecadrine treatment induced a decrease in basal leptin secretion compared to the untreated animals. Insulin-stimulated leptin secretion reached similar levels in adipocytes of the overweight rats as in lean animals. There was a trend for insulin-induced leptin secretion to be lower at 24 h in Trecadrine-treated rats, but it did not reach statistical significance. In conclusion, adipocytes of diet-induced overweight animals have a higher basal leptin secretion, which is reduced by treatment with Trecadrine. However, neither the cafeteria diet nor the Trecadrine treatment significantly alters the ability of adipocytes to increase leptin secretion in response to insulin.
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Affiliation(s)
- María J Moreno-Aliaga
- Department of Physiology and Nutrition, University of Navarra, 31008 Pamplona, Spain.
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Gómez-Ambrosi J, Frühbeck G, Martínez JA. Interactions between an alpha2-adrenergic antagonist and a beta3-adrenergic agonist on the expression of UCP2 and UCP3 in rats. J Physiol Biochem 2002; 58:17-23. [PMID: 12222743 DOI: 10.1007/bf03179834] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
This experimental trial was devised to assess whether selective beta3-adrenergic receptor (AR) stimulation and simultaneous blockade of alpha2-AR would affect thermoregulation. With this purpose, the individual and combined administration of a beta-AR agonist, trecadrine, and an alpha2-AR antagonist, yohimbine, were evaluated. Yohimbine produced a marked decrease (p < 0.001) in body temperature one hour after administration (5 mg kg(-1), i.p.) and blocked the thermogenic effect of trecadrine (1 mg kg(-1), i.p.) when simultaneously administered. Uncoupling protein-2 expression in skeletal muscle was downregulated (p < 0.05) by trecadrine, while yohimbine had no effect. White adipose tissue UCP2 and muscle UCP3 were not modified by either trecadrine or yohimbine administration. Liver UCP2 mRNA expression was significantly decreased by yohimbine (p < 0.05). However, this downregulation does not seem to explain the reduction in temperature produced by yohimbine given the fact that trecadrine produced a similar downregulation of hepatic UCP2 (p < 0.05). The present work indicates that alpha2-AR antagonism blocks the thermogenic effects mediated by beta3-AR stimulation, contrary to our expectations, suggesting a possible interplay between both mechanisms. Moreover, these effects are not apparently explained by changes in UCP2 and UCP3.
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Affiliation(s)
- J Gómez-Ambrosi
- Departamento de Fisiología y Nutricion, Universidad de Navarra, Spain
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Margareto J, Rivero I, Monge A, Aldana I, Marti A, Martínez JA. Changes in UCP2, PPARgamma2, and c/EBPalpha gene expression induced by a neuropeptide Y (NPY) related receptor antagonist in overweight rats. Nutr Neurosci 2002; 5:13-7. [PMID: 11929193 DOI: 10.1080/10284150290007065] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Neuropeptide Y (NPY), a peptide released by nervous cells, appears to contribute to adiposity regulation by increasing food intake and inhibiting lipolysis. New NPY receptor related antagonists such as S.A.0204 are being developed as potential anti-obesity drugs affecting adipocyte lipid metabolism and thermogenesis. In this sense, those animals fed on a high-energy yielding (cafeteria) diet decreased body fat weight as compared to overweight controls, when they were administered with S.A.0204, and increased body temperature, which statistically correlated with high UCP2 mRNA expression levels in white adipose tissue. In addition, the in vivo NPY-antagonist administration was able to prevent white adipose tissue growth in animals fed the cafeteria (high-fat) diet by impairing PPARy and CIEBPalpha mRNA expression in white fat cells. In summary, this novel NPY related-antagonist S.A.0204 may regulate body fat deposition by affecting both energy dissipation and white adipose tissue deposition, representing a potential new pharmacological strategy for obesity management.
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Affiliation(s)
- J Margareto
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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41
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Margareto J, Marti A, Martínez JA. Modification of RXRalpha expression according to the duration of a cafeteria diet. J Physiol Biochem 2001; 57:347-8. [PMID: 12005039 DOI: 10.1007/bf03179830] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- J Margareto
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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Hatakeyama Y, Scarpace PJ. Transcriptional regulation of uncoupling protein-2 gene expression in L6 myotubes. Int J Obes (Lond) 2001; 25:1619-24. [PMID: 11753581 DOI: 10.1038/sj.ijo.0801812] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2000] [Revised: 04/23/2001] [Accepted: 05/08/2001] [Indexed: 01/04/2023]
Abstract
OBJECTIVE To increase the understanding of the transcriptional regulation of UCP2 gene expression in skeletal muscle cells, we examined the effect of all-trans-retinoic acid (tRA), a ligand (after the conversion to 9-cis-RA) of the retinoid X receptor (RXR), and linolenic acid, a polyunsaturated fatty acid and peroxisome proliferator-activated receptors (PPARs) ligand, on the expression of UCP2 mRNA in cultured L6 myotubes. RESEARCH METHODS AND PROCEDURES UCP2 gene expression in L6 myotubes was confirmed by Northern blot analysis. The time- and concentration-dependency of tRA and linolenic acid on UCP2 gene expression was assessed by dot blot quantification. The mRNA levels of PPAR subtypes (alpha, gamma and delta) were determined by RT-PCR. RESULTS tRA induced UCP2 gene expression in a time- and concentration-dependent manner. Similar to tRA, UCP2 mRNA was markedly increased by 0.5 mM linolenic acid. In L6 myotubes, PPARdelta mRNA was abundant, whereas PPARalpha mRNA was lower and PPARgamma mRNA was minimal. CONCLUSIONS UCP2 mRNA expression in L6 myotubes is up-regulated by tRA and linolenic acid, possibly through a mechanism involving PPAR and RXRs.
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MESH Headings
- Animals
- Blotting, Northern
- Cells, Cultured
- DNA Primers
- Dose-Response Relationship, Drug
- Gene Expression Regulation
- Ion Channels
- Membrane Transport Proteins
- Mitochondrial Proteins
- Muscle, Skeletal/cytology
- Proteins/genetics
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- Rats
- Receptors, Cytoplasmic and Nuclear/administration & dosage
- Receptors, Retinoic Acid/drug effects
- Receptors, Retinoic Acid/genetics
- Retinoid X Receptors
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factors/administration & dosage
- Transcription Factors/drug effects
- Transcription Factors/genetics
- Transcription Factors/pharmacology
- Transcription, Genetic
- Tretinoin/administration & dosage
- Tretinoin/pharmacology
- Uncoupling Protein 2
- alpha-Linolenic Acid/administration & dosage
- alpha-Linolenic Acid/pharmacology
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Affiliation(s)
- Y Hatakeyama
- Department of Metabolic Diseases, Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co. Ltd, Osaka, Japan.
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Margareto J, Larrarte E, Marti A, Martinez JA. Up-regulation of a thermogenesis-related gene (UCP1) and down-regulation of PPARgamma and aP2 genes in adipose tissue: possible features of the antiobesity effects of a beta3-adrenergic agonist. Biochem Pharmacol 2001; 61:1471-8. [PMID: 11377376 DOI: 10.1016/s0006-2952(01)00562-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A number of experiments have demonstrated the antiobesity effects of beta(3)-adrenergic receptor stimulation by promoting thermogenesis and/or lipolysis. While many studies have been performed in order to develop beta(3)-adrenergic agonists as a novel strategy in the management of obesity, more information is needed about the mechanisms involved in thermogenesis and the actions of these drugs on adipocyte differentiation. To address this, the possible thermogenic and antiadipogenic properties of Tertatolol, a beta(3)-adrenergic agonist, in a diet-induced obesity model has been tested. Animals fed on a high-fat diet gained more weight and fat mass as compared with control and high-fat fed animals treated with Tertatolol. A RT-PCR was carried out in white adipose tissue specific genes involved in thermogenesis such as uncoupling proteins (UCPs) and adipogenesis such as peroxisome proliferator-activated receptor (PPARgamma2), retinoid receptors (RXRalpha/RARalpha), and fatty acid binding protein (aP2). Levels of UCP1 mRNA were augmented in the Tertatolol-treated group as compared to non-treated high-fat fed animals, while the beta(3)-adrenergic agonist treatment significantly decreased the expression levels of aP2 and transcription factors such as PPARgamma2 and the ratio RXRalpha/RARalpha as compared to obese rats. Altogether these data suggest that the antiobesity effects of beta(3)-adrenergic agonists are not limited to the promotion of thermogenesis and/or lipolysis and support the implication that these beta(3)-adrenergic agonists also affect fat deposition by impairing adipogenesis in white adipose tissue (WAT).
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Affiliation(s)
- J Margareto
- Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain
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Margareto J, Gómez-Ambrosi J, Marti A, Martínez JA. Time-dependent effects of a high-energy-yielding diet on the regulation of specific white adipose tissue genes. Biochem Biophys Res Commun 2001; 283:6-11. [PMID: 11322759 DOI: 10.1006/bbrc.2001.4733] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
White adipose tissue development is regulated by many factors, including the energy content of food and the genetic background. Nevertheless, little is known about possible differential effects of high-fat palatable diets when fed for short or long-time periods. Thus, the expression of certain genes involved with lipid metabolism (peroxisome proliferator-activated receptor gamma, PPARgamma2; retinoic receptors; fatty acid binding protein, aP2 and uncoupling proteins, UCP) may be affected by those dietary manipulations (high-energy-yielding diet and time duration of feeding). High-fat feeding for 8 days decreased mRNA UCP3 levels compared to control fed animals, while feeding for 30 days increased them over controls. Similar findings occurred for PPARgamma2 and aP2. Furthermore, statistically significant associations were found among PPARgamma2, aP2 and UCP3 mRNA levels. These data suggest a physiological time-dependent response seeking to prevent excessive fat deposition when animals are fed for short-term with a high amount of dietary fat, which was followed by an adaptive period to the high-energy content of diet throughout a coregulation among certain lipid metabolism related genes: PPARgamma2, aP2, UCP3.
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Affiliation(s)
- J Margareto
- Department of Physiology and Nutrition, University of Navarra, Pamplona, 31008, Spain
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Nedergaard J, Golozoubova V, Matthias A, Asadi A, Jacobsson A, Cannon B. UCP1: the only protein able to mediate adaptive non-shivering thermogenesis and metabolic inefficiency. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1504:82-106. [PMID: 11239487 DOI: 10.1016/s0005-2728(00)00247-4] [Citation(s) in RCA: 444] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The uniqueness of UCP1 (as compared to UCP2/UCP3) is evident from expression analysis and ablation studies. UCP1 expression is positively correlated with metabolic inefficiency, being increased by cold acclimation (in adults or perinatally) and overfeeding, and reduced in fasting and genetic obesity. Such a simple relationship is not observable for UCP2/UCP3. Studies with UCP1-ablated animals substantiate the unique role of UCP1: the phenomenon of adaptive adrenergic non-shivering thermogenesis in the intact animal is fully dependent on the presence of UCP1, and so is any kind of cold acclimation-recruited non-shivering thermogenesis; thus UCP2/UCP3 (or any other proteins or metabolic processes) cannot substitute for UCP1 physiologically, irrespective of their demonstrated ability to show uncoupling in reconstituted systems or when ectopically expressed. Norepinephrine-induced thermogenesis in brown-fat cells is absolutely dependent on UCP1, as is the uncoupled state and the recoupling by purine nucleotides in isolated brown-fat mitochondria. Although very high UCP2/UCP3 mRNA levels are observed in brown adipose tissue of UCP1-ablated mice, there is no indication that the isolated brown-fat mitochondria are uncoupled; thus, high expression of UCP2/UCP3 does not necessarily confer to the mitochondria of a tissue a propensity for being innately uncoupled. Whereas the thermogenic effect of fatty acids in brown-fat cells is fully UCP1-dependent, this is not the case in brown-fat mitochondria; this adds complexity to the issues concerning the mechanisms of UCP1 function and the pathway from beta(3)-adrenoceptor stimulation to UCP1 activation and thermogenesis. In addition to amino acid sequences conserved in all UCPs as part of the tripartite structure, all UCPs contain certain residues associated with nucleotide binding. However, conserved amongst all UCP1s so far sequenced, and without parallel in all UCP2/UCP3, are two sequences: 144SHLHGIKP and the C-terminal sequence RQTVDC(A/T)T; these sequences may therefore be essential for the unique thermogenic function of UCP1. The level of UCP1 in the organism is basically regulated at the transcriptional level (physiologically probably mainly through the beta(3)-adrenoceptor/CREB pathway), with influences from UCP1 mRNA stability and from the delay caused by translation. It is concluded that UCP1 is unique amongst the uncoupling proteins and is the only protein able to mediate adaptive non-shivering thermogenesis and the ensuing metabolic inefficiency.
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Affiliation(s)
- J Nedergaard
- The Wenner-Gren Institute, The Arrhenius Laboratories F3, Stockholm University, SE-106 91 Stockholm, Sweden.
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Margareto J, Marti A, Martínez JA. Changes in UCP mRNA expression levels in brown adipose tissue and skeletal muscle after feeding a high-energy diet and relationships with leptin, glucose and PPARgamma. J Nutr Biochem 2001; 12:130-137. [PMID: 11257461 DOI: 10.1016/s0955-2863(00)00131-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Brown adipose tissue and skeletal muscle are known to be important sites for nonshivering thermogenesis. In this context, it is accepted that uncoupling proteins (UCPs) are involved in such process, but little is known about the physiological regulation of these proteins as affected by the intake of a high-energy (cafeteria) diet inducing fat deposition. In this study, the UCP messenger RNA (mRNA) expression in interscapular brown adipose tissue (iBAT) and skeletal muscle was assessed to evaluate the influence of a dietary manipulation on energy homeostasis regulation. We report a statistically significant increase in mRNA levels of iBAT UCP1 and UCP3 and a statistical marginal rise in skeletal muscle UCP3 mRNA expression after feeding a high-energy diet, whereas no changes in UCP2 expression were found in either tissue. Furthermore, significant positive associations between iBAT UCP1 and UCP3 mRNA levels with serum leptin were found. Although the expression of the beta(3) adrenoceptor (beta(3)AR) was about 50% in the lean controls compared with the obese group in iBAT, no statistically significant changes were observed concerning peroxisome proliferator-activated receptor gamma2 (PPARgamma2) mRNA levels in muscle or iBAT. We conclude that feeding a diet inducing weight and fat gain produces different outcomes on iBAT and skeletal muscle UCP mRNA expression, revealing a tissue-dependent response for the three UCPs. Results suggest that the regulation of UCP expression in both tissues under these specific dietary conditions may be related to leptin circulating levels.
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Affiliation(s)
- J Margareto
- Department of Physiology and Nutrition, University of Navarra, 31008, Pamplona, Navarra, Spain
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