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Human Semaphorin 3 Variants Link Melanocortin Circuit Development and Energy Balance.
van der Klaauw AA, Croizier S, Mendes de Oliveira E, Stadler LKJ, Park S, Kong Y, Banton MC, Tandon P, Hendricks AE, Keogh JM, Riley SE, Papadia S, Henning E, Bounds R, Bochukova EG, Mistry V, O'Rahilly S, Simerly RB, INTERVAL, UK10K Consortium, Minchin JEN, Barroso I, Jones EY, Bouret SG, Farooqi IS
(2019) Cell 176: 729-742.e18
MeSH Terms: Adolescent, Adult, Animals, Body Weight, Cell Line, Child, Child, Preschool, Disease Models, Animal, Eating, Energy Metabolism, Female, Genetic Variation, Homeostasis, Humans, Hypothalamus, Leptin, Male, Melanocortins, Mice, Mice, Inbred C57BL, Middle Aged, Nerve Tissue Proteins, Neurons, Obesity, Receptors, Cell Surface, Semaphorins, Young Adult, Zebrafish
Show Abstract · Added April 11, 2019
Hypothalamic melanocortin neurons play a pivotal role in weight regulation. Here, we examined the contribution of Semaphorin 3 (SEMA3) signaling to the development of these circuits. In genetic studies, we found 40 rare variants in SEMA3A-G and their receptors (PLXNA1-4; NRP1-2) in 573 severely obese individuals; variants disrupted secretion and/or signaling through multiple molecular mechanisms. Rare variants in this set of genes were significantly enriched in 982 severely obese cases compared to 4,449 controls. In a zebrafish mutagenesis screen, deletion of 7 genes in this pathway led to increased somatic growth and/or adiposity demonstrating that disruption of Semaphorin 3 signaling perturbs energy homeostasis. In mice, deletion of the Neuropilin-2 receptor in Pro-opiomelanocortin neurons disrupted their projections from the arcuate to the paraventricular nucleus, reduced energy expenditure, and caused weight gain. Cumulatively, these studies demonstrate that SEMA3-mediated signaling drives the development of hypothalamic melanocortin circuits involved in energy homeostasis.
Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.
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28 MeSH Terms
Caloric Restriction-Induced Decreases in Dopamine Receptor Availability are Associated with Leptin Concentration.
Dunn JP, Abumrad NN, Kessler RM, Patterson BW, Li R, Marks-Shulman P, Tamboli RA
(2017) Obesity (Silver Spring) 25: 1910-1915
MeSH Terms: Adult, Brain, Caloric Restriction, Female, Humans, Leptin, Obesity, Receptors, Dopamine D2
Show Abstract · Added March 14, 2018
OBJECTIVE - It has been previously reported that early after Roux-en-Y-gastric bypass, dopamine (DA) type 2 and 3 receptor (D2/3R) binding potential (BP ) was decreased from preoperative levels. The current study aimed to determine whether calorie restriction without weight loss modifies D2/3R BP and whether such changes are explained by neuroendocrine regulation.
METHODS - Fifteen females with obesity (BMI = 39 ± 6 kg/m ) were studied before and after ∼10 days of a very-low-calorie-diet (VLCD). Outcome measures included fasting insulin, leptin, acyl ghrelin, and glucose, and insulin sensitivity and disposition index were estimated using the oral-minimal model (OMM) method. Participants underwent positron emission tomography scanning with the displaceable radioligand [ F]fallypride to estimate available regional D2/3R levels. Regions of interest included the caudate, putamen, ventral striatum, hypothalamus, and substantia nigra (SN).
RESULTS - With the VLCD, weight decreased slightly (-3 kg). Insulin, glucose, and leptin decreased significantly, but there was no change in acyl ghrelin or measures from OMM. SN D2/3R BP decreased significantly, with trends toward decreased levels in the remaining regions. The decrease in leptin concentration strongly predicted the change in D2/3R BP in all regions (all P ≤ 0.004).
CONCLUSIONS - In obesity, reductions in regional D2/3R availability after VLCD are suggestive of increased endogenous DA competing with the radioligand. Changes in regional D2/3R availability were associated with decreases in leptin concentrations that occurred before clinically significant weight loss.
© 2017 The Obesity Society.
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8 MeSH Terms
A critical period for the trophic actions of leptin on AgRP neurons in the arcuate nucleus of the hypothalamus.
Kamitakahara A, Bouyer K, Wang CH, Simerly R
(2018) J Comp Neurol 526: 133-145
MeSH Terms: Age Factors, Agouti-Related Protein, Analysis of Variance, Animals, Animals, Newborn, Arcuate Nucleus of Hypothalamus, Axons, ELAV-Like Protein 3, Estrogen Receptor alpha, Female, Green Fluorescent Proteins, Integrases, Leptin, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Neurons, Neuropeptide Y, Receptors, Leptin, STAT3 Transcription Factor
Show Abstract · Added April 11, 2019
In the developing hypothalamus, the fat-derived hormone leptin stimulates the growth of axons from the arcuate nucleus of the hypothalamus (ARH) to other regions that control energy balance. These projections are significantly reduced in leptin deficient (Lep ) mice and this phenotype is largely rescued by neonatal leptin treatments. However, treatment of mature Lep mice is ineffective, suggesting that the trophic action of leptin is limited to a developmental critical period. To temporally delineate closure of this critical period for leptin-stimulated growth, we treated Lep mice with exogenous leptin during a variety of discrete time periods, and measured the density of Agouti-Related Peptide (AgRP) containing projections from the ARH to the ventral part of the dorsomedial nucleus of the hypothalamus (DMHv), and to the medial parvocellular part of the paraventricular nucleus (PVHmp). The results indicate that leptin loses its neurotrophic potential at or near postnatal day 28. The duration of leptin exposure appears to be important, with 9- or 11-day treatments found to be more effective than shorter (5-day) treatments. Furthermore, leptin treatment for 9 days or more was sufficient to restore AgRP innervation to both the PVHmp and DMHv in Lep females, but only to the DMHv in Lep males. Together, these findings reveal that the trophic actions of leptin are contingent upon timing and duration of leptin exposure, display both target and sex specificity, and that modulation of leptin-dependent circuit formation by each of these factors may carry enduring consequences for feeding behavior, metabolism, and obesity risk.
© 2017 Wiley Periodicals, Inc.
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MeSH Terms
Leptogenic effects of NAPE require activity of NAPE-hydrolyzing phospholipase D.
Chen Z, Zhang Y, Guo L, Dosoky N, de Ferra L, Peters S, Niswender KD, Davies SS
(2017) J Lipid Res 58: 1624-1635
MeSH Terms: Animals, Arabidopsis, Hydrolysis, Leptin, Mice, Phosphatidylethanolamines, Phospholipase D
Show Abstract · Added April 10, 2018
Food intake induces synthesis of -acylphosphatidylethanolamines (NAPEs) in the intestinal tract. While NAPEs exert leptin-like (leptogenic) effects, including reduced weight gain and food intake, the mechanisms by which NAPEs induce these leptogenic effects remain unclear. One key question is whether intestinal NAPEs act directly on cognate receptors or first require conversion to -acylethanolamides (NAEs) by NAPE-hydrolyzing phospholipase D (NAPE-PLD). Previous studies using mice were equivocal because intraperitoneal injection of NAPEs led to nonspecific aversive effects. To avoid the aversive effects of injection, we delivered NAPEs and NAEs intestinally using gut bacteria synthesizing these compounds. Unlike in wild-type mice, increasing intestinal levels of NAPE using NAPE-synthesizing bacteria in mice failed to reduce food intake and weight gain or alter gene expression. In contrast, increasing intestinal NAE levels in mice using NAE-synthesizing bacteria induced all of these effects. These NAE-synthesizing bacteria also markedly increased NAE levels and decreased inflammatory gene expression in omental adipose tissue. These results demonstrate that intestinal NAPEs require conversion to NAEs by the action of NAPE-PLD to exert their various leptogenic effects, so that the reduced intestinal NAPE-PLD activity found in obese subjects may directly contribute to excess food intake and obesity.
Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.
1 Communities
2 Members
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MeSH Terms
Counterregulatory responses to hypoglycemia differ between glimepiride and glyburide in non diabetic individuals.
Joy NG, Tate DB, Davis SN
(2015) Metabolism 64: 729-37
MeSH Terms: Adult, Blood Glucose, C-Peptide, Female, Glucagon, Glucose Clamp Technique, Glyburide, Humans, Hypoglycemia, Hypoglycemic Agents, Insulin, Leptin, Male, Pancreatic Polypeptide, Single-Blind Method, Sulfonylurea Compounds
Show Abstract · Added July 30, 2015
OBJECTIVE - Reported rates of hypoglycemia in patients with type 2 diabetes mellitus are lower with glimepiride as compared to glyburide. The aim of this study was to determine whether physiologic differences in counterregulatory neuroendocrine and metabolic mechanisms during hypoglycemia provide a basis for the observed clinical differences between glimepiride and glyburide.
RESEARCH DESIGN AND METHODS - Non-diabetic volunteers (age 38±2years, BMI 26±1kg/m(2)) were studied in a single-blind fashion during separate 2day randomized protocols consisting of 2h hyperinsulinemic (9pmol/kg/min) euglycemic (4.9±0.1mmol) and hypoglycemic (2.9±0.1mmol/L) clamps. Individuals received biologically equivalent doses of glimepiride (4mg) or glyburide (10mg) 1h prior to each glucose clamp (n=11) as well as a control group of placebo studies. Glucose kinetics were calculated using D-Glucose-6-6d2.
RESULTS - Insulin and C-peptide levels were increased (p<0.05) during euglycemia in both sulfonylurea groups as compared to placebo. However, despite equivalent hypoglycemia, insulin and C-peptide levels were higher (p<0.05) only after glyburide. Glucagon responses and endogenous glucose production (EGP) were decreased (p<0.05) during hypoglycemia following glyburide administration as compared to glimepiride. Glyburide reduced (p<0.05) norepinephrine responses during euglycemic clamps. In addition combined epinephrine and norepinephrine responses during hypoglycemia were reduced (p<0.05) following glyburide as compared to placebo. Leptin levels fell by a greater amount (p<0.05) during hypoglycemia with both sulfonylureas as compared to placebo.
CONCLUSIONS - In summary, glimepiride and glyburide can both similarly increase insulin and C-peptide levels during hyperinsulinemic euglycemia. However, during moderate hyperinsulinemic hypoglycemia (2.9mmol/L) glyburide resulted in increased C-peptide and insulin, but blunted glucagon, sympathetic nervous system and EGP responses. We conclude that glyburide can acutely reduce key neuroendocrine and metabolic counterregulatory defenses during hypoglycemia in healthy individuals.
Copyright © 2015. Published by Elsevier Inc.
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2 Resources
16 MeSH Terms
Metabolic adaptation following massive weight loss is related to the degree of energy imbalance and changes in circulating leptin.
Knuth ND, Johannsen DL, Tamboli RA, Marks-Shulman PA, Huizenga R, Chen KY, Abumrad NN, Ravussin E, Hall KD
(2014) Obesity (Silver Spring) 22: 2563-9
MeSH Terms: Adult, Basal Metabolism, Body Composition, Body Mass Index, Body Weight, Energy Metabolism, Female, Gastric Bypass, Humans, Leptin, Male, Middle Aged, Obesity, Morbid, Weight Loss
Show Abstract · Added January 20, 2015
OBJECTIVE - To measure changes in resting metabolic rate (RMR) and body composition in obese subjects following massive weight loss achieved via bariatric surgery or calorie restriction plus vigorous exercise.
METHODS - Body composition and RMR were measured in 13 pairs of obese subjects retrospectively matched for sex, body mass index, weight, and age who underwent either Roux-en-Y gastric bypass surgery (RYGB) or participated in "The Biggest Loser" weight loss competition (BLC).
RESULTS - Both groups had similar final weight loss (RYGB: 40.2 ± 12.7 kg, BLC: 48.8 ± 14.9 kg; P = 0.14); however, RYGB lost a larger proportion of their weight as fat-free mass (FFM) (RYGB: 30 ± 12%, BLC: 16 ± 8% [P < 0.01]). In both groups, RMR decreased significantly more than expected based on measured body composition changes. The magnitude of this metabolic adaptation was correlated with the degree of energy imbalance (r = 0.55, P = 0.004) and the decrease in circulating leptin (r = 0.47, P = 0.02).
CONCLUSIONS - Calorie restriction along with vigorous exercise in BLC participants resulted in preservation of FFM and greater metabolic adaption compared to RYGB subjects despite comparable weight loss. Metabolic adaptation was related to the degree of energy imbalance and the changes in circulating leptin.
© 2014 The Obesity Society.
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2 Members
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14 MeSH Terms
Pigmented rice bran and plant sterol combination reduces serum lipids in overweight and obese adults.
Hongu N, Kitts DD, Zawistowski J, Dossett CM, Kopeć A, Pope BT, Buchowski MS
(2014) J Am Coll Nutr 33: 231-8
MeSH Terms: Adult, Basal Metabolism, Blood Pressure, Body Composition, Body Mass Index, C-Reactive Protein, Caloric Restriction, Cholesterol, HDL, Cholesterol, LDL, Diet, Reducing, Dietary Fiber, Double-Blind Method, F2-Isoprostanes, Female, Humans, Insulin, Leptin, Male, Middle Aged, Motor Activity, Obesity, Overweight, Patient Compliance, Phytosterols, Triglycerides, Weight Loss, Young Adult
Show Abstract · Added July 30, 2015
OBJECTIVE - This study investigated the dietary effect of including pigmented rice bran with or without plant sterols on lipid profiles during energy restriction-induced weight loss in overweight and obese adults not taking cholesterol-lowering medication. In addition, the study examined the effect of intervention on biomarkers of oxidative stress and inflammation.
METHODS - A group of 24 overweight and obese adults (age: 43 ± 6 years, body mass index 32 ± 1 kg/m(2), 18 females) were randomized to a 25% calorie-restricted diet containing either pigmented rice bran (RB) or the RB with addition of plant sterols (RB+PS) snack bars for 8 weeks. The individualized nutrient-balanced diet contained ∼70% of daily energy needs assessed from indirect calorimetry measured resting energy expenditure (EE) and physical activity-related EE assessed using accelerometry. Anthropometrics, blood pressure, blood lipids, glucose, urinary F2-isoprostanes, C-reactive protein, insulin, and leptin were measured at baseline and after 8 weeks of intervention.
RESULTS - Participants lost approximately 4.7 ± 2.2 kg (p < 0.001). Weight loss was not significant between the RB+PS and RB group (p = 0.056). Changes in body fat corresponded to changes in body weight. Average decrease in total cholesterol was significantly higher in the RB+PS group than in the RB group (difference 36 ± 25 g/dL vs 7 ± 16 g/dL; p = 0.044). A similar pattern was observed for the decrease in low-density lipoprotein (LDL) cholesterol (difference 22.3 ± 25.2 g/dL vs 4.4 ± 18.9 g/dL; p = 0.062). Changes in systolic blood pressure, serum levels of leptin, and F2-isoprostanes were significant between baseline values and after 8 weeks on the diet in both groups (p < 0.05) but did not differ between the 2 groups.
CONCLUSIONS - A nutrient-balanced and energy-restricted diet supplemented with rice bran and plant sterols resulted in a significant decrease in total and LDL cholesterol in overweight and obese adults.
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27 MeSH Terms
Early weight regain after gastric bypass does not affect insulin sensitivity but is associated with elevated ghrelin.
Tamboli RA, Breitman I, Marks-Shulman PA, Jabbour K, Melvin W, Williams B, Clements RH, Feurer ID, Abumrad NN
(2014) Obesity (Silver Spring) 22: 1617-22
MeSH Terms: Adult, Anastomosis, Roux-en-Y, Female, Ghrelin, Humans, Insulin Resistance, Leptin, Longitudinal Studies, Male, Middle Aged, Obesity, Postoperative Period, Recurrence, Weight Gain
Show Abstract · Added May 27, 2014
OBJECTIVES - We sought to determine: (1) if early weight regain between 1 and 2 years after Roux-en-Y gastric bypass (RYGB) is associated with worsened hepatic and peripheral insulin sensitivity, and (2) if preoperative levels of ghrelin and leptin are associated with early weight regain after RYGB.
METHODS - Hepatic and peripheral insulin sensitivity and ghrelin and leptin plasma levels were assessed longitudinally in 45 subjects before RYGB and at 1 month, 6 months, 1 year, and 2 years postoperatively. Weight regain was defined as ≥5% increase in body weight between 1 and 2 years after RYGB.
RESULTS - Weight regain occurred in 33% of subjects, with an average increase in body weight of 10 ± 5% (8.5 ± 3.3 kg). Weight regain was not associated with worsening of peripheral or hepatic insulin sensitivity. Subjects with weight regain after RYGB had higher preoperative and postoperative levels of ghrelin compared to those who maintained or lost weight during this time. Conversely, the trajectories of leptin levels corresponded with the trajectories of fat mass in both groups.
CONCLUSIONS - Early weight regain after RYGB is not associated with a reversal of improvements in insulin sensitivity. Higher preoperative ghrelin levels might identify patients that are more susceptible to weight regain after RYGB.
Copyright © 2014 The Obesity Society.
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14 MeSH Terms
Administration of IL-1ra improves adiponectin levels in chronic hemodialysis patients.
Hung AM, Limkunakul C, Placido JS, Siew ED, Ellis CD, Shintani A, Ikizler TA
(2014) J Nephrol 27: 681-8
MeSH Terms: Adiponectin, Adult, Aged, Anti-Inflammatory Agents, Biomarkers, Female, Humans, Inflammation, Insulin Resistance, Interleukin 1 Receptor Antagonist Protein, Leptin, Male, Middle Aged, Pilot Projects, Renal Dialysis, Renal Insufficiency, Chronic, Tennessee, Time Factors, Treatment Outcome, Up-Regulation
Show Abstract · Added March 21, 2014
BACKGROUND - Adiponectin, an adipose tissue derived hormone, is known to have insulin-sensitizing, anti-inflammatory, and anti-atherogenic properties in the general population. Adiponectin secretion is suppressed by systemic inflammation, a highly prevalent condition in maintenance hemodialysis (MHD) patients. We evaluated whether short-term administration of interleukin 1 receptor antagonist (IL-1ra) improves adiponectin levels and insulin sensitivity in MHD patients.
METHODS - Ad hoc analysis was performed on a pilot randomized placebo-controlled trial of the administration of IL-1ra in chronically inflamed MHD patients. Twenty-two patients were randomly assigned to receive 100 mg of IL-1ra or placebo (1:1) for 4 weeks, and 14 completed the trial. ANCOVA was used to compare percent change from baseline to 4 weeks. The primary outcome was percent change in adiponectin and the secondary outcomes were changes in leptin, homeostatic model assessment of insulin resistance (HOMA-IR) and the leptin-to-adiponectin ratio (LAR).
RESULTS - Patients' mean age was 49 ± 13 years, and 71 % were males. At baseline, the median values for adiponectin, leptin, LAR and HOMA-IR were 11.5 μg/ml [interquartile range (IQR) 9, 28.5], 17.8 ng/ml (3.9, 50.0), 2.20 (0.13, 3.98), and 2.8 (2.0, 3.6), respectively. IL-1ra administration resulted in a mean percent increase in serum adiponectin of 22 % vs. 14 % decrease in the placebo arm (p = 0.003). Leptin, LAR or HOMA-IR levels did not change in either arm.
CONCLUSIONS - Short-term administration of IL-1ra significantly increased adiponectin levels among prevalent MHD patients. The intervention did not impact insulin sensitivity parameters. Studies of longer duration and larger sample size are needed to further evaluate the potential effect of anti-inflammatory interventions on metabolic markers and insulin sensitivity in MHD patients.
0 Communities
4 Members
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20 MeSH Terms
Role of vascular oxidative stress in obesity and metabolic syndrome.
Youn JY, Siu KL, Lob HE, Itani H, Harrison DG, Cai H
(2014) Diabetes 63: 2344-55
MeSH Terms: Adipogenesis, Animals, Cytochrome b Group, Diet, High-Fat, Drug Resistance, Leptin, Male, Metabolic Syndrome, Mice, Mice, Inbred C57BL, Mice, Transgenic, Muscle, Smooth, Vascular, NADPH Oxidases, Obesity, Oxidative Stress, Reactive Oxygen Species, Vascular Diseases
Show Abstract · Added March 31, 2015
Obesity is associated with vascular diseases that are often attributed to vascular oxidative stress. We tested the hypothesis that vascular oxidative stress could induce obesity. We previously developed mice that overexpress p22phox in vascular smooth muscle, tg(sm/p22phox), which have increased vascular ROS production. At baseline, tg(sm/p22phox) mice have a modest increase in body weight. With high-fat feeding, tg(sm/p22phox) mice developed exaggerated obesity and increased fat mass. Body weight increased from 32.16 ± 2.34 g to 43.03 ± 1.44 g in tg(sm/p22phox) mice (vs. 30.81 ± 0.71 g to 37.89 ± 1.16 g in the WT mice). This was associated with development of glucose intolerance, reduced HDL cholesterol, and increased levels of leptin and MCP-1. Tg(sm/p22phox) mice displayed impaired spontaneous activity and increased mitochondrial ROS production and mitochondrial dysfunction in skeletal muscle. In mice with vascular smooth muscle-targeted deletion of p22phox (p22phox(loxp/loxp)/tg(smmhc/cre) mice), high-fat feeding did not induce weight gain or leptin resistance. These mice also had reduced T-cell infiltration of perivascular fat. In conclusion, these data indicate that vascular oxidative stress induces obesity and metabolic syndrome, accompanied by and likely due to exercise intolerance, vascular inflammation, and augmented adipogenesis. These data indicate that vascular ROS may play a causal role in the development of obesity and metabolic syndrome.
© 2014 by the American Diabetes Association.
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17 MeSH Terms