scholarly journals Tpcn2 knockout mice have improved insulin sensitivity and are protected against high-fat diet-induced weight gain

2018 ◽  
Vol 50 (8) ◽  
pp. 605-614
Author(s):  
Hong He ◽  
Katie Holl ◽  
Sarah DeBehnke ◽  
Chay Teng Yeo ◽  
Polly Hansen ◽  
...  
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Glucose Tolerance ◽  
Knockout Mice ◽  
High Fat Diet ◽  
Wild Type ◽  
High Fat ◽  
Male And Female ◽  
Female Mice

Type 2 diabetes is a complex disorder affected by multiple genes and the environment. Our laboratory has shown that in response to a glucose challenge, two-pore channel 2 ( Tpcn2) knockout mice exhibit a decreased insulin response but normal glucose clearance, suggesting they have improved insulin sensitivity compared with wild-type mice. We tested the hypothesis that improved insulin sensitivity in Tpcn2 knockout mice would protect against the negative effects of a high fat diet. Male and female Tpcn2 knockout (KO), heterozygous (Het), and wild-type (WT) mice were fed a low-fat (LF) or high-fat (HF) diet for 24 wk. HF diet significantly increases body weight in WT mice relative to those on the LF diet; this HF diet-induced increase in body weight is blunted in the Het and KO mice. Despite the protection against diet-induced weight gain, however, Tpcn2 KO mice are not protected against HF-diet-induced changes in glucose or insulin area under the curve during glucose tolerance tests in female mice, while HF diet has no significant effect on glucose tolerance in the male mice, regardless of genotype. Glucose disappearance during an insulin tolerance test is augmented in male KO mice, consistent with our previous findings suggesting enhanced insulin sensitivity in these mice. Male KO mice exhibit increased fasting plasma total cholesterol and triglyceride concentrations relative to WT mice on the LF diet, but this difference disappears in HF diet-fed mice where there is increased cholesterol and triglycerides across all genotypes. These data demonstrate that knockout of Tpcn2 may increase insulin action in male, but not female, mice. In addition, both male and female KO mice are protected against diet-induced weight gain, but this protection is likely independent from glucose tolerance, insulin sensitivity, and plasma lipid levels.

scholarly journals High fat-fed GPR55 null mice display impaired glucose tolerance without concomitant changes in energy balance or insulin sensitivity but are less responsive to the effects of the cannabinoids rimonabant or Δ(9)-tetrahydrocannabivarin on weight gain

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9811
Author(s):  
Edward T. Wargent ◽  
Malgorzata Kepczynska ◽  
Mohamed Sghaier Zaibi ◽  
David C. Hislop ◽  
Jonathan R.S. Arch ◽  
...  
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Weight Gain ◽  
Energy Balance ◽  
Glucose Tolerance ◽  
Glucose Homeostasis ◽  
High Fat Diet ◽  
Wild Type ◽  
High Fat ◽  
Insulin Tolerance

Background The insulin-sensitizing phytocannabinoid, Δ(9)-tetrahydrocannabivarin (THCV) can signal partly via G-protein coupled receptor-55 (GPR55 behaving as either an agonist or an antagonist depending on the assay). The cannabinoid receptor type 1 (CB1R) inverse agonist rimonabant is also a GPR55 agonist under some conditions. Previous studies have shown varied effects of deletion of GPR55 on energy balance and glucose homeostasis in mice. The contribution of signalling via GPR55 to the metabolic effects of THCV and rimonabant has been little studied. Methods In a preliminary experiment, energy balance and glucose homeostasis were studied in GPR55 knockout and wild-type mice fed on both standard chow (to 20 weeks of age) and high fat diets (from 6 to 15 weeks of age). In the main experiment, all mice were fed on the high fat diet (from 6 to 14 weeks of age). In addition to replicating the preliminary experiment, the effects of once daily administration of THCV (15 mg kg−1 po) and rimonabant (10 mg kg−1 po) were compared in the two genotypes. Results There was no effect of genotype on absolute body weight or weight gain, body composition measured by either dual-energy X-ray absorptiometry or Nuclear Magnetic Resonance (NMR), fat pad weights, food intake, energy expenditure, locomotor activity, glucose tolerance or insulin tolerance in mice fed on chow. When the mice were fed a high fat diet, there was again no effect of genotype on these various aspects of energy balance. However, in both experiments, glucose tolerance was worse in the knockout than the wild-type mice. Genotype did not affect insulin tolerance in either experiment. Weight loss in rimonabant- and THCV-treated mice was lower in knockout than in wild-type mice, but surprisingly there was no detectable effect of genotype on the effects of the drugs on any aspect of glucose homeostasis after taking into account the effect of genotype in vehicle-treated mice. Conclusions Our two experiments differ from those reported by others in finding impaired glucose tolerance in GPR55 knockout mice in the absence of any effect on body weight, body composition, locomotor activity or energy expenditure. Nor could we detect any effect of genotype on insulin tolerance, so the possibility that GPR55 regulates glucose-stimulated insulin secretion merits further investigation. By contrast with the genotype effect in untreated mice, we found that THCV and rimonabant reduced weight gain, and this effect was in part mediated by GPR55.

Deletion of PTP 1B from Brain Neurons Partly Protects Mice from Diet-Induced Obesity and Minimally Improves Fertility

Endocrinology ◽  
2021 ◽  
Author(s):  
Caroline M Ancel ◽  
Maggie C Evans ◽  
Romy I Kerbus ◽  
Elliot G Wallace ◽  
Greg M Anderson
Keyword(s):  
Body Weight ◽  
Weight Gain ◽  
Glucose Tolerance ◽  
Knockout Mice ◽  
Body Weight Gain ◽  
Negative Regulator ◽  
Cytokine Signaling ◽  
Male And Female ◽  
Female Mice ◽  
Calorie Diet

Abstract Reproductive dysfunction in women has been linked to high calorie diet (HCD)-feeding and obesity. Central resistance to leptin and insulin have been shown to accompany diet-induced infertility in rodent studies, and we have previously shown that deleting suppressor of cytokine signaling 3, which is a negative regulator of leptin signaling, from all forebrain neurons partially protects mice from HCD-induced infertility. In this study, we were interested in exploring the role of protein tyrosine phosphatase 1B (PTP1B), which is a negative regulator of both leptin and insulin signaling, in the pathophysiology of HCD-induced obesity and infertility. To this end, we generated male and female neuron-specific PTP1B knockout mice and compared their body weight gain, food intake, glucose tolerance and fertility to control littermates under both normal calorie diet-feeding and HCD-feeding conditions. Both male and female mice with neuronal PTP1B deletion exhibited slower body weight gain in response to HCD-feeding, yet only male knockout mice exhibited improved glucose tolerance compared with controls. Neuronal PTP1B deletion improved the time to first litter in HCD-fed mice, but did not protect female mice from eventual HCD-induced infertility. While the mice fed a normal caloric diet remained fertile throughout the 150 day period of assessment, HCD-fed females became infertile after producing only a single litter, regardless of their genotype. These data show that neuronal PTP1B deletion is able to partially protect mice from HCD-induced obesity, but is not a critical mediator of HCD-induced infertility.

scholarly journals Role of PTP1B in POMC neurons during chronic high-fat diet: sex differences in regulation of liver lipids and glucose tolerance

2018 ◽  
Vol 314 (3) ◽  
pp. R478-R488 ◽  
Author(s):  
Nicola Aberdein ◽  
Robert J. Dambrino ◽  
Jussara M. do Carmo ◽  
Zhen Wang ◽  
Laura E. Mitchell ◽  
...  
Keyword(s):  
Sex Differences ◽  
Weight Gain ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Acute Stress ◽  
Negative Regulator ◽  
High Fat ◽  
Male And Female ◽  
Female Mice

Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of leptin receptor signaling and may contribute to leptin resistance in diet-induced obesity. Although PTP1B inhibition has been suggested as a potential weight loss therapy, the role of specific neuronal PTP1B signaling in cardiovascular and metabolic regulation and the importance of sex differences in this regulation are still unclear. In this study, we investigated the impact of proopiomelanocortin (POMC) neuronal PTP1B deficiency in cardiometabolic regulation in male and female mice fed a high-fat diet (HFD). When compared with control mice (PTP1B flox/flox), male and female mice deficient in POMC neuronal PTP1B (PTP1B flox/flox/POMC-Cre) had attenuated body weight gain (males: −18%; females: −16%) and fat mass (males: −33%; female: −29%) in response to HFD. Glucose tolerance was improved by 40%, and liver lipid accumulation was reduced by 40% in PTP1B/POMC-Cre males but not in females. When compared with control mice, deficiency of POMC neuronal PTP1B did not alter mean arterial pressure (MAP) in male or female mice (males: 112 ± 1 vs. 112 ± 1 mmHg in controls; females: 106 ± 3 vs. 109 ± 3 mmHg in controls). Deficiency of POMC neuronal PTP1B also did not alter MAP response to acute stress in males or females compared with control mice (males: Δ32 ± 0 vs. Δ29 ± 4 mmHg; females: Δ22 ± 2 vs. Δ27 ± 4 mmHg). These data demonstrate that POMC-specific PTP1B deficiency improved glucose tolerance and attenuated diet-induced fatty liver only in male mice and attenuated weight gain in males and females but did not enhance the MAP and HR responses to a HFD or to acute stress.

scholarly journals Partial Deficiency of Zfp217 Resists High-Fat Diet-Induced Obesity by Increasing Energy Metabolism in Mice

2021 ◽  
Vol 22 (10) ◽  
pp. 5390
Author(s):  
Qianhui Zeng ◽  
Nannan Wang ◽  
Yaru Zhang ◽  
Yuxuan Yang ◽  
Shuangshuang Li ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Weight Gain ◽  
Insulin Sensitivity ◽  
Energy Metabolism ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Chow Diet ◽  
High Fat ◽  
Glycolipid Metabolism ◽  
Partial Deficiency

Obesity-induced adipose tissue dysfunction and disorders of glycolipid metabolism have become a worldwide research priority. Zfp217 plays a crucial role in adipogenesis of 3T3-L1 preadipocytes, but about its functions in animal models are not yet clear. To explore the role of Zfp217 in high-fat diet (HFD)-induced obese mice, global Zfp217 heterozygous knockout (Zfp217+/−) mice were constructed. Zfp217+/− mice and Zfp217+/+ mice fed a normal chow diet (NC) did not differ significantly in weight gain, percent body fat mass, glucose tolerance, or insulin sensitivity. When challenged with HFD, Zfp217+/− mice had less weight gain than Zfp217+/+ mice. Histological observations revealed that Zfp217+/− mice fed a high-fat diet had much smaller white adipocytes in inguinal white adipose tissue (iWAT). Zfp217+/− mice had improved metabolic profiles, including improved glucose tolerance, enhanced insulin sensitivity, and increased energy expenditure compared to the Zfp217+/+ mice under HFD. We found that adipogenesis-related genes were increased and metabolic thermogenesis-related genes were decreased in the iWAT of HFD-fed Zfp217+/+ mice compared to Zfp217+/− mice. In addition, adipogenesis was markedly reduced in mouse embryonic fibroblasts (MEFs) from Zfp217-deleted mice. Together, these data indicate that Zfp217 is a regulator of energy metabolism and it is likely to provide novel insight into treatment for obesity.

scholarly journals Carbonyl Reductase 1 Overexpression in Adipose Amplifies Local Glucocorticoid Action and Impairs Glucose Tolerance in Lean Mice

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A806-A806
Author(s):  
Rachel Bell ◽  
Elisa Villalobos ◽  
Mark Nixon ◽  
Allende Miguelez-Crespo ◽  
Matthew Sharp ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Glucose Tolerance ◽  
Fat Mass ◽  
High Fat Diet ◽  
Fasting Glucose ◽  
High Fat ◽  
Male And Female ◽  
Over Expression ◽  
Female Mice ◽  
Diet Induced Obesity

Abstract Glucocorticoids play a critical role in metabolic homeostasis. Chronic or excessive activation of the glucocorticoid receptor (GR) in adipose tissue contributes to metabolic disorders such as glucose intolerance and insulin resistance. Steroid-metabolising enzymes in adipose, such as 11β-HSD1 or 5α-reductase, modulate the activation of GR by converting primary glucocorticoids into more or less potent ligands. Carbonyl reductase 1 (CBR1) is a novel regulator of glucocorticoid metabolism, converting corticosterone/cortisol to 20β-dihydrocorticosterone/cortisol (20β-DHB/F); a metabolite which retains GR activity. CBR1 is abundant in adipose tissue and increased in obese adipose of mice and humans1 and increased Cbr1 expression is associated with increased fasting glucose1. We hypothesised that increased Cbr1/20β-DHB in obese adipose contributes to excessive GR activation and worsens glucose tolerance. We generated a novel murine model of adipose-specific Cbr1 over-expression (R26-Cbr1Adpq) by crossing conditional knock-in mice with Adiponectin-Cre mice. CBR1 protein and activity were doubled in subcutaneous adipose tissue of male and female R26-Cbr1Adpq mice compared with floxed controls; corresponding to a two-fold increase 20β-DHB (1.6 vs. 4.2ng/g adipose; P=0.0003; n=5-7/group). There were no differences in plasma 20β-DHB or corticosterone. Bodyweight, lean or fat mass, did not differ between male or female R26-Cbr1Adpq mice and floxed controls. Lean male R26-Cbr1Adpq mice had higher fasting glucose (9.5±0.3 vs. 8.4±0.3mmol/L; P=0.04) and worsened glucose tolerance (AUC 1819±66 vs. 1392±14; P=0.03). Female R26-Cbr1Adpq mice also had a worsened glucose tolerance but fasting glucose was not altered with genotype. There were no differences in fasting insulin or non-esterified fatty acid between genotypes in either sex. Expression of GR-induced genes Pnpla2, Gilz and Per1, were increased in adipose of R26-Cbr1Adpq mice. Following high-fat diet induced obesity, no differences in bodyweight, lean or fat mass, with genotype were observed in male and female mice, and genotype differences in fasting glucose and glucose tolerance were abolished. In conclusion, adipose-specific over-expression of Cbr1 in lean male and female mice led to increased levels of 20β-DHB in adipose but not plasma, and both sexes having worsened glucose tolerance. The influence of adipose CBR1/20β-DHB on glucose tolerance was not associated with altered fat mass or bodyweight and was attenuated by high-fat diet-induced obesity. These metabolic consequences of Cbr1 manipulation require careful consideration given the wide variation in CBR1 expression in the human population, the presence of inhibitors and enhancers in many foodstuffs and the proposed use of inhibitors as an adjunct for cancer treatment regimens. Reference: Morgan et al., Scientific Reports. 2017; 7.

scholarly journals Modulation of Gr1low monocyte subset impacts insulin sensitivity and weight gain upon high-fat diet in female mice

2017 ◽  
Vol 41 (12) ◽  
pp. 1805-1814 ◽  
Author(s):  
S Béliard ◽  
W Le Goff ◽  
F Saint-Charles ◽  
L Poupel ◽  
V Deswaerte ◽  
...  
Keyword(s):  
Weight Gain ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Monocyte Subset ◽  
High Fat ◽  
Female Mice

Chronic benzylamine administration in the drinking water improves glucose tolerance, reduces body weight gain and circulating cholesterol in high-fat diet-fed mice

2010 ◽  
Vol 61 (4) ◽  
pp. 355-363 ◽  
Author(s):  
Zsuzsa Iffiú-Soltész ◽  
Estelle Wanecq ◽  
Almudena Lomba ◽  
Maria P. Portillo ◽  
Federica Pellati ◽  
...  
Keyword(s):  
Drinking Water ◽  
Body Weight ◽  
Weight Gain ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Body Weight Gain ◽  
High Fat

Nobiletin Prevents High-Fat Diet-Induced Dysregulation of Intestinal Lipid Metabolism and Attenuates Postprandial Lipemia

2021 ◽  
Author(s):  
Nadya M. Morrow ◽  
Natasha A. Trzaskalski ◽  
Antonio A. Hanson ◽  
Evgenia Fadzeyeva ◽  
Dawn E. Telford ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Postprandial Lipemia ◽  
Intestinal Morphology ◽  
High Fat ◽  
Male And Female ◽  
Female Mice ◽  
Triglyceride Accumulation ◽  
Phosphorylated Akt

Objective: Nobiletin is a dietary flavonoid that improves insulin resistance and atherosclerosis in mice with metabolic dysfunction. Dysregulation of intestinal lipoprotein metabolism contributes to atherogenesis. The objective of the study was to determine if nobiletin targets the intestine to improve metabolic dysregulation in both male and female mice. Approach and Results: Triglyceride-rich lipoprotein (TRL) secretion, intracellular triglyceride kinetics, and intestinal morphology were determined in male and female LDL (low-density lipoprotein) receptor knockout, and male wild-type mice fed a standard laboratory diet or high-fat, high-cholesterol diet ± nobiletin using an olive oil gavage, radiotracers, and electron microscopy. Nobiletin attenuated postprandial TRL levels in plasma and enhanced TRL clearance. Nobiletin reduced fasting jejunal triglyceride accumulation through accelerated TRL secretion and lower jejunal fatty acid synthesis with no impact on fatty acid oxidation. Fasting-refeeding experiments revealed that nobiletin led to higher levels of phosphorylated AKT and FoxO1 (forkhead box O1) and normal Srebf1-c expression indicating increased insulin sensitivity. Intestinal length and weight were diminished by high-fat feeding and restored by nobiletin. Both fasting and postprandial plasma GLP-1 (glucagon-like peptide-1; and likely GLP-2) were elevated in response to nobiletin. Treatment with a GLP-2 receptor antagonist, GLP-2(3-33), reduced villus length in high fat-fed mice but did not impact TRL secretion in any diet group. In contrast to males, nobiletin did not improve postprandial lipid parameters in female mice. Conclusions: Nobiletin opposed the effects of the high-fat diet by normalizing intestinal de novo lipogenesis through improved insulin sensitivity. Nobiletin prevents postprandial lipemia because the enhanced TRL clearance more than compensates for increased TRL secretion.

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