scholarly journals Recent advances in understanding leptin signaling and leptin resistance

2009 ◽  
Vol 297 (6) ◽  
pp. E1247-E1259 ◽  
Author(s):  
David L. Morris ◽  
Liangyou Rui
Keyword(s):  
Endoplasmic Reticulum ◽  
Body Weight ◽  
Risk Factor ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Leptin Resistance ◽  
Leptin Signaling ◽  
Long Form ◽  
The Brain ◽  
Primary Risk Factor

The brain controls energy homeostasis and body weight by integrating various metabolic signals. Leptin, an adipose-derived hormone, conveys critical information about peripheral energy storage and availability to the brain. Leptin decreases body weight by both suppressing appetite and promoting energy expenditure. Leptin directly targets hypothalamic neurons, including AgRP and POMC neurons. These leptin-responsive neurons widely connect to other neurons in the brain, forming a sophisticated neurocircuitry that controls energy intake and expenditure. The anorexigenic actions of leptin are mediated by LEPRb, the long form of the leptin receptor, in the hypothalamus. LEPRb activates both JAK2-dependent and -independent pathways, including the STAT3, PI 3-kinase, MAPK, AMPK, and mTOR pathways. These pathways act coordinately to form a network that fully mediates leptin response. LEPRb signaling is regulated by both positive (e.g., SH2B1) and negative (e.g., SOCS3 and PTP1B) regulators and by endoplasmic reticulum stress. Leptin resistance, a primary risk factor for obesity, likely results from impairment in leptin transport, LEPRb signaling, and/or the neurocircuitry of energy balance.

scholarly journals Signaling through Tyr985 of Leptin Receptor as an Age/Diet-Dependent Switch in the Regulation of Energy Balance

2009 ◽  
Vol 30 (7) ◽  
pp. 1650-1659 ◽  
Author(s):  
Jia You ◽  
Yue Yu ◽  
Lei Jiang ◽  
Wenxia Li ◽  
Xinxin Yu ◽  
...  
Keyword(s):  
Energy Balance ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Negative Regulator ◽  
Leptin Resistance ◽  
Leptin Signaling ◽  
Diet Induced Obesity ◽  
Long Form ◽  
Elevated Expression ◽  
Multiple Signaling

ABSTRACT Leptin regulates energy homeostasis through central activation of multiple signaling pathways mediated by Ob-Rb, the long form of leptin receptor. Leptin resistance underlies the pathogenic development of obesity, which is closely associated with environmental factors. To further understand the physiological function of leptin signaling mechanisms, we generated a knock-in line of mice (Y985F) expressing a mutant Ob-Rb with a phenylalanine substitution for Tyr985, one of the three intracellular tyrosines that mediate leptin's signaling actions. Surprisingly, whereas young homozygous Y985F animals were slightly leaner, they exhibit adult-onset or diet-induced obesity. Importantly, both age-dependent and diet-induced deterioration of energy balance was paralleled with pronounced leptin resistance, which was largely attributable to attenuation of leptin-responsive hypothalamic STAT3 activation as well as prominently elevated expression of hypothalamic SOCS3, a key negative regulator of leptin signaling. Thus, these results unmask distinct binary roles for Try985-mediated signaling in energy metabolism, acting as an age/diet-dependent regulatory switch to counteract age-associated or diet-induced obesity.

scholarly journals Changes in Expression of the Genes for the Leptin Signaling in Hypothalamic-Pituitary Selected Areas and Endocrine Responses to Long-Term Manipulation in Body Weight and Resistin in Ewes

2020 ◽  
Vol 21 (12) ◽  
pp. 4238
Author(s):  
Dorota Anna Zieba ◽  
Weronika Biernat ◽  
Malgorzata Szczesna ◽  
Katarzyna Kirsz ◽  
Justyna Barć ◽  
...  
Keyword(s):  
Body Weight ◽  
Leptin Receptor ◽  
Fat Body ◽  
Density Lipoprotein ◽  
Reproductive Hormones ◽  
Leptin Resistance ◽  
Nonesterified Fatty Acid ◽  
Cytokine Signaling ◽  
Leptin Signaling

Both long-term undernutrition and overnutrition disturb metabolic balance, which is mediated partially by the action of two adipokines, leptin and resistin (RSTN). In this study, we manipulated the diet of ewes to produce either a thin (lean) or fat (fat) body condition and investigated how RSTN affects endocrine and metabolic status under different leptin concentrations. Twenty ewes were distributed into four groups (n = 5): the lean and fat groups were administered with saline (Lean and Fat), while the Lean-R (Lean-Resistin treated) and Fat-R (Fat-Resistin treated) groups received recombinant bovine resistin. Plasma was assayed for LH, FSH, PRL, RSTN, leptin, GH, glucose, insulin, total cholesterol, nonesterified fatty acid (NEFA), high-density lipoprotein (HDL)-cholesterol, low-density lipoprotein (LDL)-cholesterol and triglycerides. Expression levels of a suppressor of cytokine signaling (SOCS-3) and the long form of the leptin receptor (LRb) were determined in selected brain regions, such as the anterior pituitary, hypothalamic arcuate nucleus, preoptic area and ventro- and dorsomedial nuclei. The results indicate long-term alterations in body weight affect RSTN-mediated effects on metabolic and reproductive hormones concentrations and the expression of leptin signaling components: LRb and SOCS-3. This may be an adaptive mechanism to long-term changes in adiposity during the state of long-day leptin resistance.

scholarly journals Leptin Signaling Is Required for Leucine Deprivation-enhanced Energy Expenditure

2013 ◽  
Vol 289 (3) ◽  
pp. 1779-1787 ◽  
Author(s):  
Qian Zhang ◽  
Bin Liu ◽  
Ying Cheng ◽  
Qingshu Meng ◽  
Tingting Xia ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
High Fat Diet ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Normal Diet ◽  
Leptin Resistance ◽  
High Fat ◽  
Leptin Signaling ◽  
Fat Loss ◽  
Stimulation Of

Leptin signaling in the hypothalamus is crucial in energy homeostasis. We have previously shown that dietary deprivation of the essential amino acid leucine in mice stimulates fat loss by increasing energy expenditure. The involvement of leptin signaling in this regulation, however, has not been reported. Here, we show that leucine deprivation promotes leptin signaling in mice maintained on an otherwise normal diet and restores leptin responses in mice maintained on a high fat diet, a regimen known to induce leptin resistance. In addition, we found that leucine deprivation stimulated energy expenditure, and fat loss was largely blocked in db/db mice homozygous for a mutation in leptin receptor and a knock-in mouse line Y3F with abrogation of leptin receptor Tyr1138-mediated signal transducer and activator transcript 3 signaling. Overall, our studies describe a novel link between hypothalamic leptin signaling and stimulation of energy expenditure under leucine deprivation.

scholarly journals Acute Blockade of PACAP-Dependent Activity in the Ventromedial Nucleus of the Hypothalamus Disrupts Leptin-Induced Behavioral and Molecular Changes in Rats

2019 ◽  
Vol 110 (3-4) ◽  
pp. 271-281
Author(s):  
Matthew M. Hurley ◽  
Eden M. Anderson ◽  
Christopher Chen ◽  
Brian Maunze ◽  
Evan M. Hess ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Receptor Activation ◽  
Leptin Resistance ◽  
Bdnf Mrna ◽  
Leptin Signaling ◽  
Obesity And Diabetes ◽  
Stat3 Phosphorylation ◽  
Pacap Receptors

Leptin signaling pathways, stemming primarily from the hypothalamus, are necessary for maintaining normal energy homeostasis and body weight. In both rodents and humans, dysregulation of leptin signaling leads to morbid obesity and diabetes. Since leptin resistance is considered a primary factor underlying obesity, understanding the regulation of leptin signaling could lead to therapeutic tools and provide insights into the causality of obesity. While leptin actions in some hypothalamic regions such as the arcuate nuclei have been characterized, less is known about leptin activity in the hypothalamic ventromedial nuclei (VMN). Recently, pituitary adenylate cyclase-activating polypeptide (PACAP) has been shown to reduce feeding behavior and alter metabolism when administered into the VMN in a pattern similar to that of leptin. In the current study, we examined whether leptin and PACAP actions in the VMN share overlapping pathways in the regulation of energy balance. Interestingly, PACAP administration into the VMN increased STAT3 phosphorylation and SOCS3 mRNA expression, both of which are hallmarks of leptin receptor activation. In addition, BDNF mRNA expression in the VMN was increased by both leptin and PACAP administration. Moreover, antagonizing PACAP receptors fully reversed the behavioral and cellular effects of leptin injections into the VMN. Electrophysiological studies further illustrated that leptin-induced effects on VMN neurons were blocked by antagonizing PACAP receptors. We conclude that leptin dependency on PACAP signaling in the VMN suggests a potential common signaling cascade, allowing a tonically and systemically secreted neuropeptide to be more precisely regulated by central neuropeptides.

scholarly journals Arcuate Nucleus-Specific Leptin Receptor Gene Therapy Attenuates the Obesity Phenotype of Koletsky (fak/fak) Rats

Endocrinology ◽  
2003 ◽  
Vol 144 (5) ◽  
pp. 2016-2024 ◽  
Author(s):  
Gregory J. Morton ◽  
Kevin D. Niswender ◽  
Christopher J. Rhodes ◽  
Martin G. Myers ◽  
James E. Blevins ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Body Weight ◽  
Food Intake ◽  
Energy Homeostasis ◽  
Arcuate Nucleus ◽  
Leptin Receptor ◽  
Receptor Expression ◽  
Wild Type ◽  
Leptin Signaling ◽  
Adenoviral Gene Therapy

Leptin signaling in the hypothalamic arcuate nucleus (ARC) is hypothesized to play an important role in energy homeostasis. To investigate whether leptin signaling limited to this brain area is sufficient to reduce food intake and body weight, we used adenoviral gene therapy to express the signaling isoform of the leptin receptor, leprb, in the ARC of leptin receptor-deficient Koletsky (fak/fak) rats. Successful expression of adenovirus containing leprb (Ad-leprb) selectively in the ARC was documented by in situ hybridization. Using real-time PCR, we further demonstrated that bilateral microinjection of Ad-leprb into the ARC restored low hypothalamic levels of leprb mRNA to values approximating those of wild-type (Fak/Fak) controls. Restored leptin receptor expression in the ARC reduced both mean daily food intake (by 13%) and body weight gain (by 33%) and increased hypothalamic proopiomelanocortin mRNA by 65% while decreasing neuropeptide Y mRNA levels by 30%, relative to fak/fak rats injected with a control adenovirus (Ad-lacZ) (P < 0.05 for each comparison). In contrast, Ad-leprb delivery to either the lateral hypothalamic area of fak/fak rats or to the ARC of wild-type Fak/Fak rats had no effect on any of these parameters. These findings collectively support the hypothesis that leptin receptor signaling in the ARC is sufficient to mediate major effects of leptin on long-term energy homeostasis. Adenoviral gene therapy is thus a viable strategy with which to study the physiological importance of specific molecules acting in discrete brain areas.

scholarly journals Leptin resistance: unsolved diagnostic issues

2018 ◽  
Vol 64 (1) ◽  
pp. 62-66
Author(s):  
Daria A. Borodkina ◽  
Olga V. Gruzdeva ◽  
Olga E. Akbasheva ◽  
Ekaterina V. Belik ◽  
Elena I. Palicheva ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Skeletal Muscles ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Leptin Resistance ◽  
Fatty Tissue ◽  
Leptin Receptors ◽  
Secretion Regulation ◽  
Tissue Sensitivity

Leptin and its receptors are key regulators of body weight and energy homeostasis. A decrease in tissue sensitivity to leptin leads to the development of obesity, insulin resistance, dyslipidemia, etc. Currently, the phenomenon of leptin resistance is explained by a number of mechanisms, including impairment of gene structure, leptin transport through the blood-brain barrier, and leptin receptor signaling. However, it is not known, a decrease in the number of receptors of which area leads to the development of leptin resistance. No relationship has been found between the basal leptin level in obesity and expression of leptin receptors in the skeletal muscles. It is also important to investigate the contribution of fatty tissue of different localization to leptin secretion regulation and activity of its receptors. The term «leptin resistence» reflects a complex pathophysiological phenomenon with broad perspectives for study. In this review, we analyze methods of diagnosing leptin resistance.

scholarly journals The leptin-dependent and -independent melanocortin signaling system: regulation of feeding and energy expenditure

2007 ◽  
Vol 193 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Hiroyuki Shimizu ◽  
Kinji Inoue ◽  
Masatomo Mori
Keyword(s):  
Energy Expenditure ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Signaling System ◽  
Leptin Signaling ◽  
Melanocyte Stimulating Hormone ◽  
Hypothalamic Nuclei ◽  
Hypothalamic Arcuate Nucleus ◽  
Melanocortin Signaling ◽  
The Brain

The brain hypothalamus coordinates extra-hypothalamic regions to maintain energy homeostasis through the regulation of food intake and energy expenditure. A number of anorexigenic and orexigenic molecules in the hypothalamic nuclei participate in the control of energy homeostasis. Leptin and pro-opiomelanocortin (POMC)-derived α-melanocyte-stimulating hormone are key anorectic molecules, and the leptin receptor and POMC gene are both expressed in the hypothalamic arcuate nucleus. Although it has been considered that melanocortin signaling is localized downstream to leptin signaling, data have accumulated to support the concept of a leptin-independent melanocortin signaling system. We focus on and review the melanocortin signaling system that functions dependently or independently of leptin signaling in the regulation of energy homeostasis.

scholarly journals Leptin resistance: unsolved diagnostic issues

2018 ◽  
Vol 64 (1) ◽  
pp. 62-66
Author(s):  
Daria A. Borodkina ◽  
Olga V. Gruzdeva ◽  
Olga E. Akbasheva ◽  
Ekaterina V. Belik ◽  
Elena I. Palicheva ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Body Weight ◽  
Skeletal Muscles ◽  
Energy Homeostasis ◽  
Leptin Receptor ◽  
Leptin Resistance ◽  
Fatty Tissue ◽  
Leptin Receptors ◽  
Secretion Regulation ◽  
Tissue Sensitivity

Leptin and its receptors are key regulators of body weight and energy homeostasis. A decrease in tissue sensitivity to leptin leads to the development of obesity, insulin resistance, dyslipidemia, etc. Currently, the phenomenon of leptin resistance is explained by a number of mechanisms, including impairment of gene structure, leptin transport through the blood-brain barrier, and leptin receptor signaling. However, it is not known, a decrease in the number of receptors of which area leads to the development of leptin resistance. No relationship has been found between the basal leptin level in obesity and expression of leptin receptors in the skeletal muscles. It is also important to investigate the contribution of fatty tissue of different localization to leptin secretion regulation and activity of its receptors. The term «leptin resistence» reflects a complex pathophysiological phenomenon with broad perspectives for study. In this review, we analyze methods of diagnosing leptin resistance.

scholarly journals Lztfl1/BBS17 controls energy homeostasis by regulating the leptin signaling in the hypothalamic neurons

2018 ◽  
Vol 10 (5) ◽  
pp. 402-410 ◽  
Author(s):  
Qun Wei ◽  
Yi-Feng Gu ◽  
Qing-Jun Zhang ◽  
Helena Yu ◽  
Yan Peng ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Signaling Pathway ◽  
Energy Homeostasis ◽  
Leucine Zipper ◽  
Molecular Mechanisms ◽  
Leptin Receptor ◽  
Energy State ◽  
Leptin Resistance ◽  
Leptin Signaling ◽  
Wide Range

Abstract Leptin receptor (LepRb) signaling pathway in the hypothalamus of the forebrain controls food intake and energy expenditure in response to an altered energy state. Defects in the LepRb signaling pathway can result in leptin-resistance and obesity. Leucine zipper transcription factor like 1 (Lztfl1)/BBS17 is a member of the Bardet–Biedl syndrome (BBS) gene family. Human BBS patients have a wide range of pathologies including obesity. The cellular and molecular mechanisms underlying Lztfl1-regulated obesity are unknown. Here, we generated Lztfl1f/f mouse model in which Lztfl1 can be deleted globally and in tissue-specific manner. Global Lztfl1 deficiency resulted in pleiotropic phenotypes including obesity. Lztfl1−/− mice are hyperphagic and showed similar energy expenditure as WT littermates. The obese phenotype of Lztfl1−/− mice is caused by the loss of Lztfl1 in the brain but not in the adipocytes. Lztfl1−/− mice are leptin-resistant. Inactivation of Lztfl1 abolished phosphorylation of Stat3 in the LepRb signaling pathway in the hypothalamus upon leptin stimulation. Deletion of Lztfl1 had no effect on LepRb membrane localization. Furthermore, we observed that Lztfl1−/− mouse embryonic fibroblasts (MEFs) have significantly longer cilia than WT MEFs. We identified several proteins that potentially interact with Lztfl1. As these proteins are known to be involved in regulation of actin/cytoskeleton dynamics, we suggest that Lztfl1 may regulate leptin signaling and ciliary structure via these proteins. Our study identified Lztfl1 as a novel player in the LepRb signaling pathway in the hypothalamus that controls energy homeostasis.

Abstract 37: Endoplasmic Reticulum Stress in the Brain Contributes to the Pathogenesis of Non-alcoholic Fatty Liver Disease

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Colin N Young ◽  
Frederick N Dong ◽  
Julie A Horwath ◽  
Allyn L Mark ◽  
Robin L Davisson
Keyword(s):  
Endoplasmic Reticulum ◽  
Body Weight ◽  
Risk Factor ◽  
Liver Disease ◽  
Er Stress ◽  
Fatty Liver Disease ◽  
Vehicle Control ◽  
Alcoholic Fatty Liver ◽  
The Brain ◽  
Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a major risk factor for the development of cardiovascular diseases (CVD), including hypertension. While most studies have focused on peripheral mechanisms mediating hepatic dysfunction, a role for the central nervous system in the pathogenesis of NAFLD is less appreciated. Here we tested the hypothesis that endoplasmic reticulum (ER) stress in the brain contributes to the development of NAFLD. First , adult male C57Bl/6 mice were instrumented with an intracerebroventricular (ICV) cannula for administration of the ER stress inducer thapsigargin (TG; 1 μg/day; 3 days; n=5), or vehicle control (n=4), and allowed 1 week recovery. Short-term induction of ER stress in the brain, using TG, did not alter body weight (26±1 vs. 27±1 g; vehicle vs. TG; p<0.05), food intake or adiposity, but caused a ~20% increase in liver weight (1.04±0.5 vs. 1.25±0.07 g; vehicle vs. TG; p<0.05). ICV TG also elicited an increase in liver lipid droplet accumulation (0.074±0.002 vs. 0.665±0.060 droplets/cm 2 ; vehicle vs. TG; p<0.05) and up-regulated hepatic gluconeogenic and lipogenic markers (e.g. Pepck mRNA 1.56±0.13 fold vehicle; p<0.05). Second , male C57Bl/6 mice either remained on normal chow (n=6) or were fed a high fat diet (HFD; n=8) for a period of 20 weeks, a condition that we and others have shown results in ER stress in the brain. Mice were then implanted with an ICV cannula for administration of the chemical ER chaperone TUDCA (5 μg/day), or vehicle control, and allowed 1 week of recovery. ICV TUDCA administration over 5 days rescued HFD-induced hepatomegaly (1.77±0.18 vs. 1.19±0.07 g; HFD vehicle vs. HFD TUDCA; p<0.05) and reduced obesity-induced liver triglyceride accumulation (365±44 vs. 127±36 mM; HFD vehicle vs. HFD TUDCA; p<0.05), such that HFD ICV TUDCA treated mice were not different from controls. These data demonstrate that induction of ER stress in the brain causes hepatic lipid accumulation, independent of changes in body weight, food intake and adiposity. Furthermore, inhibition of chronic brain ER stress reduces HFD-induced hepatomegaly and hepatic steatosis. Collectively these findings illustrate a novel role for brain ER stress as a contributor to a major risk factor for CVD, NAFLD. HL63887, HL84207, AHA13POST14410020

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