scholarly journals Diet-Induced Obesity Causes Ghrelin Resistance in Arcuate NPY/AgRP Neurons

Endocrinology ◽  
2010 ◽  
Vol 151 (10) ◽  
pp. 4745-4755 ◽  
Author(s):  
Dana I. Briggs ◽  
Pablo J. Enriori ◽  
Moyra B. Lemus ◽  
Michael A. Cowley ◽  
Zane B. Andrews
Keyword(s):  
Food Intake ◽  
High Fat Diet ◽  
Healthy Aging ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
High Fat ◽  
Appetite Control ◽  
Diet Induced Obesity ◽  
Therapeutic Outcomes ◽  
The Brain

Circulating ghrelin is decreased in obesity, and peripheral ghrelin does not induce food intake in obese mice. We investigated whether ghrelin resistance was a centrally mediated phenomenon involving dysregulated neuropeptide Y (NPY) and agouti-related peptide (AgRP) circuits. We show that diet-induced obesity (DIO) (12 wk) suppresses the neuroendocrine ghrelin system by decreasing acylated and total plasma ghrelin, decreasing ghrelin and Goat mRNA in the stomach, and decreasing expression of hypothalamic GHSR. Peripheral (ip) or central (intracerebroventricular) ghrelin injection was able to induce food intake and arcuate nucleus Fos immunoreactivity in chow-fed but not high-fat diet-fed mice. DIO decreased expression of Npy and Agrp mRNA, and central ghrelin was unable to promote expression of these genes. Ghrelin did not induce AgRP or NPY secretion in hypothalamic explants from DIO mice. Injection of NPY intracerebroventricularly increased food intake in both chow-fed and high-fat diet-fed mice, indicating that downstream NPY/AgRP neural targets are intact and that defective NPY/AgRP function is a primary cause of ghrelin resistance. Ghrelin resistance in DIO is not confined to the NPY/AgRP neurons, because ghrelin did not stimulate growth hormone secretion in DIO mice. Collectively, our data suggests that DIO causes ghrelin resistance by reducing NPY/AgRP responsiveness to plasma ghrelin and suppressing the neuroendocrine ghrelin axis to limit further food intake. Ghrelin has a number of functions in the brain aside from appetite control, including cognitive function, mood regulation, and protecting against neurodegenerative diseases. Thus, central ghrelin resistance may potentiate obesity-related cognitive decline, and restoring ghrelin sensitivity may provide therapeutic outcomes for maintaining healthy aging.

scholarly journals Reversal of Diet-Induced Obesity Increases Insulin Transport into Cerebrospinal Fluid and Restores Sensitivity to the Anorexic Action of Central Insulin in Male Rats

Endocrinology ◽  
2013 ◽  
Vol 154 (3) ◽  
pp. 1047-1054 ◽  
Author(s):  
Denovan P. Begg ◽  
Joram D. Mul ◽  
Min Liu ◽  
Brianne M. Reedy ◽  
David A. D'Alessio ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Food Intake ◽  
High Fat Diet ◽  
Male Rats ◽  
Control Group ◽  
Chow Diet ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Insulin Transport ◽  
The Central Nervous System

Abstract Diet-induced obesity (DIO) reduces the ability of centrally administered insulin to reduce feeding behavior and also reduces the transport of insulin from the periphery to the central nervous system (CNS). The current study was designed to determine whether reversal of high-fat DIO restores the anorexic efficacy of central insulin and whether this is accompanied by restoration of the compromised insulin transport. Adult male Long-Evans rats were initially maintained on either a low-fat chow diet (LFD) or a high-fat diet (HFD). After 22 weeks, half of the animals on the HFD were changed to the LFD, whereas the other half continued on the HFD for an additional 8 weeks, such that there were 3 groups: 1) a LFD control group (Con; n = 18), 2) a HFD-fed, DIO group (n = 17), and 3) a HFD to LFD, DIO-reversal group (DIO-rev; n = 18). The DIO reversal resulted in a significant reduction of body weight and epididymal fat weight relative to the DIO group. Acute central insulin administration (8 mU) reduced food intake and caused weight loss in Con and DIO-rev but not DIO rats. Fasting cerebrospinal fluid insulin was higher in DIO than Con animals. However, after a peripheral bolus injection of insulin, cerebrospinal fluid insulin increased in Con and DIO-rev rats but not in the DIO group. These data provide support for previous reports that DIO inhibits both the central effects of insulin and insulin's transport to the CNS. Importantly, DIO-rev restored sensitivity to the effects of central insulin on food intake and insulin transport into the CNS.

scholarly journals SIM1 Overexpression Partially Rescues Agouti Yellow and Diet-Induced Obesity by Normalizing Food Intake

Endocrinology ◽  
2006 ◽  
Vol 147 (10) ◽  
pp. 4542-4549 ◽  
Author(s):  
Bassil M. Kublaoui ◽  
J. Lloyd Holder ◽  
Kristen P. Tolson ◽  
Terry Gemelli ◽  
Andrew R. Zinn
Keyword(s):  
Food Intake ◽  
Energy Expenditure ◽  
Transgenic Mice ◽  
High Fat Diet ◽  
Chow Diet ◽  
High Fat ◽  
Enhanced Sensitivity ◽  
Diet Induced Obesity ◽  
Melanocortin 4 Receptor ◽  
Obesity In Mice

Single-minded 1 (SIM1) mutations are associated with obesity in mice and humans. Haploinsufficiency of mouse Sim1 causes hyperphagic obesity with increased linear growth and enhanced sensitivity to a high-fat diet, a phenotype similar to that of agouti yellow and melanocortin 4 receptor knockout mice. To investigate the effects of increased Sim1 dosage, we generated transgenic mice that overexpress human SIM1 and examined their phenotype. Compared with wild-type mice, SIM1 transgenic mice had no obvious phenotype on a low-fat chow diet but were resistant to diet-induced obesity on a high-fat diet due to reduced food intake with no change in energy expenditure. The SIM1 transgene also completely rescued the hyperphagia and partially rescued the obesity of agouti yellow mice, in which melanocortin signaling is abrogated. Our results indicate that the melanocortin 4 receptor signals through Sim1 or its transcriptional targets in controlling food intake but not energy expenditure.

scholarly journals Differential Effects of Combined Soluble Epoxide Hydrolase Inhibitor t-TUCB and n-3 Epoxides in Diet-Induced Obesity

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1260-1260
Author(s):  
Yang Yang ◽  
Xinyun Xu ◽  
Christophe Morisseau ◽  
Bruce Hammock ◽  
Ahmed Bettaieb ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Protein Expression ◽  
Cold Tolerance ◽  
High Fat Diet ◽  
Epoxide Hydrolase ◽  
Soluble Epoxide Hydrolase ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Brown Adipose

Abstract Objectives Brown adipose tissue (BAT) is a promising target for obesity prevention. N-3 epoxides are fatty acid epoxides produced from n-3 polyunsaturated fatty acids and shown to be beneficial for health. However, these epoxides are unstable and quickly metabolized by the cytosolic soluble epoxide hydrolase (sEH). Here, we investigated the effects of sEH inhibitor (t-TUCB) alone or combined with two different n-3 epoxides on BAT activation in the development of diet-induced obesity and associated metabolic disorders. Methods Male C57BL6/J mice were fed a high-fat diet and received either of the following treatment: the vehicle control, t-TUCB alone (T), or t-TUCB combined with 19,20-EDP (T + EDP) or 17,18-EEQ (T + EEQ) via osmotic minipump delivery near the interscapular BAT for 6 weeks. Mice were examined for changes in body weight, food intake, glucose, insulin, and cold tolerance tests, and indirect calorimetry. Blood and tissue biochemical analyses were also performed to assess changes in metabolic homeostasis. Results Although no differences in food intake were observed, there were small but significant increases in body weight in both T and T + EDP groups. Mice in the T + EDP and T + EEQ groups showed significant decreases in fasting glucose and serum TG levels, higher core body temperature, and better cold tolerance compared to the controls. However, heat production was significantly increased only in the T + EEQ group. Thermogenic UCP1 protein expression showed a moderate, but not significant, increase in the T + EEQ group. On the other hand, PGC1 α protein expression was significantly increased in the T, T + EDP, and T + EEQ groups compared to the controls. Perilipin protein expression and phosphorylation were also significantly increased in the three treated groups. In contrast, protein expression of FABP4 and HSL was only increased in the T and T + EDP groups, and CD36 protein expression was only increased in the T + EEQ group. Conclusions Our results suggest that sEH pharmacological inhibition by t-TUCB combined with n-3 epoxides may prevent high-fat diet-induced glucose and lipid disorders, in part through increased thermogenesis and upregulating of protein expression of thermogenic and lipid metabolic genes. Funding Sources The work was supported by NIH grants to L.Z., A.B., and B.D.H.

scholarly journals Selenium Regulates Hypothalamic Control of Energy Metabolism in a Sexually Dimorphic Manner

2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1844-1844
Author(s):  
Daniel Torres ◽  
Matthew Pitts ◽  
Lucia Seale ◽  
Ann Hashimoto ◽  
Katlyn An ◽  
...  
Keyword(s):  
Energy Metabolism ◽  
Food Intake ◽  
Energy Expenditure ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Metabolic Phenotype ◽  
Sexually Dimorphic ◽  
High Fat ◽  
Diet Induced Obesity

Abstract Objectives The trace element selenium (Se) is known mainly for its antioxidant properties and is critical for proper brain function. The role of Se in regulating energy metabolism, and the sexually dimorphic nature of Se functions, however, are underappreciated, and warrant increased attention. Recent work in our lab has highlighted the importance of Se utilization in hypothalamic regulation of energy metabolism. Dietary Se is incorporated into selenoproteins in the form of the unique amino acid selenocysteine (Sec). The objective of this study was to assess the role of selenoproteins in Agouti-related peptide (Agrp)-positive neurons, an orexigenic sub-population of the hypothalamus. Methods We generated mice with Agrp-Cre-driven deletion of selenocysteine tRNA (Trsp-Agrp KO mice), which is essential for Sec incorporation into selenoproteins, thus ablating selenoprotein synthesis in Agrp-positive neurons. The metabolic phenotype of Trsp-Agrp KO mice challenged with a high-fat diet was characterized via glucose tolerance test (i.p. injection) and the use of analytical chambers to measure food intake and respiratory metabolism. Prior to sacrifice, mice were challenged with leptin (i.p. injection) to assess neuronal leptin responsivity via immunohistochemistry and western blot. Brown adipose tissue (BAT) morphology and thermogenic protein expression were also analyzed. Results Female Trsp-Agrp KO mice displayed resistance to diet-induced obesity, which was accompanied by improved glucose tolerance and elevated energy expenditure levels without changes in food intake. Female Trsp-Agrp KO mice also had greater leptin sensitivity and showed signs of elevated BAT thermogenesis. Male Trsp-Agrp KO mice displayed no changes in metabolic phenotype. Conclusions Loss of selenoproteins in Agrp-positive neurons of the hypothalamus promotes energy expenditure and reduces diet-induced obesity in a sexually dimorphic manner, leading to resistance to a high-fat diet in females. Funding Sources This work was funded by grant support from the National Institute of Diabetes and Digestive and Kidney Diseases (MJB) and Ola HAWAII, a grant from the National Institute on Minority Health and Health Disparities.

Apolipoprotein A5 deficiency aggravates high‐fat diet‐induced obesity due to impaired central regulation of food intake

2013 ◽  
Vol 27 (8) ◽  
pp. 3354-3362 ◽  
Author(s):  
Sjoerd A. A. Berg ◽  
Mattijs M. Heemskerk ◽  
Janine J. Geerling ◽  
Jan‐Bert Klinken ◽  
Frank G. Schaap ◽  
...  
Keyword(s):  
Food Intake ◽  
High Fat Diet ◽  
Central Regulation ◽  
High Fat ◽  
Apolipoprotein A5 ◽  
Diet Induced Obesity

Sucrose intake and corresponding responsive c-Fos in the brain of high-fat diet induced obesity rats

2010 ◽  
Vol 68 ◽  
pp. e389
Author(s):  
Jinrong Li ◽  
Jianqun Yan ◽  
Qian Wang ◽  
Ke Chen ◽  
Shiru Zhao ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Sucrose Intake ◽  
High Fat ◽  
Diet Induced Obesity ◽  
The Brain

scholarly journals Mass spectrometry imaging of mice brain lipid profile changes over time under high fat diet

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gianluca Sighinolfi ◽  
Samantha Clark ◽  
Landry Blanc ◽  
Daniela Cota ◽  
Boutayna Rhourri-Frih
Keyword(s):  
Mass Spectrometry ◽  
Weight Loss ◽  
Lipid Profile ◽  
High Fat Diet ◽  
Overweight And Obesity ◽  
Mass Spectrometry Analysis ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Imaging Approach ◽  
The Brain

AbstractOverweight and obesity have been shown to significantly affect brain structures and size. Obesity has been associated with cerebral atrophy, alteration of brain functions, including cognitive impairement, and psychiatric diseases such as depression. Given the importance of lipids in the structure of the brain, here, by using 47 mice fed a high fat diet (HFD) with 60% calories from fat (40% saturated fatty acids) and 20% calories from carbohydrates and age-matched control animals on a normal chow diet, we examined the effects of HFD and diet-induced obesity on the brain lipidome. Using a targeted liquid chromatography mass spectrometry analysis and a non-targeted mass spectrometry MALDI imaging approach, we show that the relative concentration of most lipids, in particular brain phospholipids, is modified by diet-induced obesity (+ 40%of body weight). Use of a non-targeted MALDI-MS imaging approach further allowed define cerebral regions of interest (ROI) involved in eating behavior and changes in their lipid profile. Principal component analysis (PCA) of the obese/chow lipidome revealed persistence of some of the changes in the brain lipidome of obese animals even after their switch to chow feeding and associated weight loss. Altogether, these data reveal that HFD feeding rapidly modifies the murine brain lipidome. Some of these HFD-induced changes persist even after weight loss, implying that some brain sequelae caused by diet-induced obesity are irreversible.

scholarly journals THE ROLE OF THE INTESTINAL MICROBIOTA IN THE MODULATION OF FOOD INTAKE AND BODY WEIGHT

2017 ◽  
Author(s):  
Matthew John Dalby
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Body Fat ◽  
Intestinal Microbiota ◽  
High Fat Diet ◽  
High Fat ◽  
Low Fat ◽  
Low Fat Diet ◽  
Diet Induced Obesity

This research investigated the role of the intestinal microbiota in shaping host food intake and body weight through immunomodulation, the impact of refined and unrefined diets, and though fermentable fibre induced gastrointestinal hormone secretion. Gut-derived lipopolysaccharide activating TLR4 has been proposed to contribute to obesity. To investigate this, TLR4-/- or CD14-/- mice and C57BL/6J controls were fed a high-fat or low-fat diet. Neither TLR4-/- or CD14-/- were protected against high-fat diet-induced obesity. High-fat diet increased hypothalamic expression of SerpinA3N and SOCS3 regardless of genotype; however, inflammatory gene expression was not increased. To investigate the use of chow control diets in obesity-associated microbiota changes, C57BL/6J mice were fed a chow diet, refined high-fat, or low-fat diet. Both high-fat and low-fat refined diets resulted in similar dramatic alterations in the composition of the intestinal microbiota at the phylum, family, and species level compared to chow, while only high-fat diet feeding resulted in obesity and glucose intolerance. The roles of colonic GLP-1 and PYY in mediating fermentable fibre in reducing food intake and body fat were investigated using GLP-1R-/- and PYY-/- mice fed a high-fat diet supplemented with inulin or cellulose. Inulin supplementation reduced body fat and food intake in C57BL/6J control mice while GLP-1R-/- and PYY-/- mice showed an attenuated response to dietary inulin. In summary, this research questions the role of TLR4 and LPS in diet-induced obesity. These results demonstrate the importance of the control diet used in studies of obesity in mice and indicate that many of the obesity-associated changes in the gut microbiota are due to comparing refined high-fat diets with chow diets. These results also provide evidence for an essential role for both GLP-1 and PYY in mediating the food intake and bodyweight-reducing effects of fermentable fibre.

scholarly journals Leanness and Low Plasma Leptin in GPR17 Knockout Mice Are Dependent on Strain and Associated With Increased Energy Intake That Is Not Suppressed by Exogenous Leptin

2021 ◽  
Vol 12 ◽  
Author(s):  
Edward T. Wargent ◽  
Suhaib J. S. Ahmad ◽  
Qing Richard Lu ◽  
Evi Kostenis ◽  
Jonathan R. S. Arch ◽  
...  
Keyword(s):  
Body Weight ◽  
Food Intake ◽  
Energy Intake ◽  
High Fat Diet ◽  
Sympathetic Activity ◽  
The Body ◽  
Whole Body ◽  
High Fat ◽  
Diet Induced Obesity ◽  
Plasma Leptin

Previous studies have shown that agonists of GPR17 stimulate, while antagonists inhibit feeding. However, whole body knockout of GPR17 in mice of the C57Bl/6 strain did not affect energy balance, whereas selective knockout in oligodendrocytes or pro-opiomelanocortin neurons provided protection from high fat diet-induced obesity and impaired glucose homeostasis. We reasoned that whole body knockout of GPR17 in mice of the 129 strain might elicit more marked effects because the 129 strain is more susceptible than the C57Bl/6 strain to increased sympathetic activity and less susceptible to high fat diet-induced obesity. Consistent with this hypothesis, compared to wild-type mice, and when fed on either a chow or a high fat diet, GPR17 -/- mice of the 129 strain displayed increased expression of uncoupling protein-1 in white adipose tissue, lower body weight and fat content, reduced plasma leptin, non-esterified fatty acids and triglycerides, and resistance to high fat diet-induced glucose intolerance. Not only energy expenditure, but also energy intake was raised. Administration of leptin did not suppress the increased food intake in GPR17 -/- mice of the 129 strain, whereas it did suppress food intake in GPR17 +/+ mice. The only difference between GPR17 +/- and GPR17 +/+ mice of the C57Bl/6 strain was that the body weight of the GPR17 -/- mice was lower than that of the GPR17 +/+ mice when the mice were fed on a standard chow diet. We propose that the absence of GPR17 raises sympathetic activity in mice of the 129 strain in response to a low plasma fuel supply, and that the consequent loss of body fat is partly mitigated by increased energy intake.

Sign in / Sign up

Export Citation Format

Share Document