scholarly journals Obesity-linked PPARγ S273 phosphorylation promotes insulin resistance through Growth Differentiation Factor 3

2020 ◽  
Author(s):  
Jessica A. Hall ◽  
Deepti Ramachandran ◽  
Hyun C. Roh ◽  
Joanna R. DiSpirito ◽  
Thiago Belchior ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Side Effects ◽  
Ectopic Expression ◽  
Bmp Signaling ◽  
Whole Body ◽  
Improve Insulin Sensitivity ◽  
Induce Insulin Resistance ◽  
Systemic Insulin Resistance

AbstractOvernutrition and obesity promote adipose tissue dysfunction, often leading to systemic insulin resistance. The thiazolidinediones (TZDs) are a potent class of insulin-sensitizing drugs and ligands of PPARγ that improve insulin sensitivity, but their use is limited due to significant side effects. Recently, we demonstrated a mechanism by which TZDs improve insulin sensitivity distinct from receptor agonism and adipogenesis: reversal of obesity-linked phosphorylation of PPARγ at Serine 273. However, the role of this modification has not been tested genetically. Here we demonstrate that mice encoding an allele of PPARγ which cannot be phosphorylated at S273 are protected from insulin resistance, without exhibiting differences in body weight or TZD-associated side effects. Indeed, hyperinsulinemic-euglycemic clamp experiments confirm improved insulin sensitivity, as evidenced by increased whole-body glucose uptake. RNA-seq experiments reveal PPARγ S273 phosphorylation specifically enhances transcription of Gdf3, a BMP family member. Ectopic expression of Gdf3 is sufficient to induce insulin resistance in lean, healthy mice. We find that Gdf3 can impact metabolism by inhibition of BMP signaling. Together, these results highlight the diabetogenic role of PPARγ S273 phosphorylation and focuses attention on a putative target, Gdf3.

scholarly journals Multiomics reveal unique signatures of human epiploic adipose tissue related to systemic insulin resistance

Gut ◽  
2021 ◽  
pp. gutjnl-2021-324603
Author(s):  
Laura Krieg ◽  
Konrad Didt ◽  
Isabel Karkossa ◽  
Stephan H Bernhart ◽  
Stephanie Kehr ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Adipose Tissue ◽  
Gastric Bypass Surgery ◽  
Whole Body ◽  
Expression Levels ◽  
Entire Cohort ◽  
Fat Depots ◽  
Systemic Insulin Resistance ◽  
Whole Body Metabolism

ObjectiveHuman white adipose tissue (AT) is a metabolically active organ with distinct depot-specific functions. Despite their locations close to the gastrointestinal tract, mesenteric AT and epiploic AT (epiAT) have only scarcely been investigated. Here, we aim to characterise these ATs in-depth and estimate their contribution to alterations in whole-body metabolism.DesignMesenteric, epiploic, omental and abdominal subcutaneous ATs were collected from 70 patients with obesity undergoing Roux-en-Y gastric bypass surgery. The metabolically well-characterised cohort included nine subjects with insulin sensitive (IS) obesity, whose AT samples were analysed in a multiomics approach, including methylome, transcriptome and proteome along with samples from subjects with insulin resistance (IR) matched for age, sex and body mass index (n=9). Findings implying differences between AT depots in these subgroups were validated in the entire cohort (n=70) by quantitative real-time PCR.ResultsWhile mesenteric AT exhibited signatures similar to those found in the omental depot, epiAT was distinct from all other studied fat depots. Multiomics allowed clear discrimination between the IS and IR states in all tissues. The highest discriminatory power between IS and IR was seen in epiAT, where profound differences in the regulation of developmental, metabolic and inflammatory pathways were observed. Gene expression levels of key molecules involved in AT function, metabolic homeostasis and inflammation revealed significant depot-specific differences with epiAT showing the highest expression levels.ConclusionMulti-omics epiAT signatures reflect systemic IR and obesity subphenotypes distinct from other fat depots. Our data suggest a previously unrecognised role of human epiploic fat in the context of obesity, impaired insulin sensitivity and related diseases.

Insulin resistance caused by hepatic cholinergic interruption and reversed by acetylcholine administration

1996 ◽  
Vol 271 (3) ◽  
pp. E587-E592 ◽  
Author(s):  
H. Xie ◽  
W. W. Lautt
Keyword(s):  
Insulin Resistance ◽  
Regression Analysis ◽  
Insulin Sensitivity ◽  
Portal Vein ◽  
Insulin Response ◽  
Whole Body ◽  
Parasympathetic Nerves ◽  
Insulin Responsiveness ◽  
Body Clearance

The role of hepatic parasympathetic nerves in insulin effectiveness was evaluated in fed anesthetized rats. Insulin sensitivity was assessed using a modified euglycemic clamp to quantitate the amount of glucose required to maintain euglycemia over 60 min after administration of insulin (50 mU/kg). With normal innervation, intraportal infusions of acetylcholine (ACh, 2.5 micrograms.kg-1.min-1) did not alter insulin sensitivity, but intraportal venous atropine (3 mg/kg) reduced insulin sensitivity (49.4 +/- 5.8%, P < 0.001, n = 7). Liver denervation resulted in reduction of insulin responsiveness by 70.8 +/- 5.8% (P < 0.001, n = 8), which was fully (96.8 +/- 12.5%) reversed by ACh. ACh into the portal vein reversed insulin resistance produced by denervation, but intravenous ACh was without effect, thus showing that the liver was the site of ACh action. Regression analysis suggests that some component of insulin response is not dependent on hepatic cholinergic nerve effects but that virtually all of the variability in response to insulin in normal fed rats tested under these conditions could be accounted for by variability in the hepatic parasympathetic-dependent insulin sensitivity. These data suggest a major role for hepatic parasympathetic nerves in regulation of whole body clearance of glucose in response to insulin.

Role of nutrition in preventing insulin resistance in children

2016 ◽  
Vol 29 (3) ◽  
Author(s):  
Annalisa Blasetti ◽  
Simone Franchini ◽  
Laura Comegna ◽  
Giovanni Prezioso ◽  
Francesco Chiarelli
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Fetal Development ◽  
Maternal Nutrition ◽  
Dietary Habits ◽  
Prenatal Period ◽  
Dietary Carbohydrates ◽  
Macro And Micronutrients

AbstractNutrition during prenatal, early postnatal and pubertal period is crucial for the development of insulin resistance and its consequences. During prenatal period fetal environment and nutrition seems to interfere with metabolism programming later in life. The type of dietary carbohydrates, glycemic index, protein, fat and micronutrient content in maternal nutrition could influence insulin sensitivity in the newborn. The effects of lactation on metabolism and nutritional behavior later in life have been studied. Dietary habits and quality of diet during puberty could prevent the onset of a pathological insulin resistance through an adequate distribution of macro- and micronutrients, a diet rich in fibers and vegetables and poor in saturated fats, proteins and sugars. We want to overview the latest evidences on the risk of insulin resistance later in life due to both nutritional behaviors and components during the aforementioned periods of life, following a chronological outline from fetal development to adolescence.

scholarly journals Hepatokine ERAP1 impairs skeletal muscle insulin sensitivity via ADRB2/PKA pathway

2020 ◽  
Author(s):  
Feifan Guo ◽  
Yuguo Niu ◽  
Haizhou Jiang ◽  
Hanrui Yin ◽  
Fenfen Wang ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Neutralizing Antibodies ◽  
Leptin Receptor ◽  
Whole Body ◽  
C2c12 Myotubes ◽  
Insulin Resistant ◽  
Skeletal Muscle Insulin Sensitivity ◽  
Pka Pathway

Abstract The current study aimed to investigate the role of endoplasmic reticulum aminopeptidase 1 (ERAP1), a novel hepatokine, in whole-body glucose metabolism. Here, we found that hepatic ERAP1 levels were increased in insulin-resistant leptin-receptor-mutated (db/db) and high-fat diet (HFD)-fed mice. Consistently, hepatic ERAP1 overexpression attenuated skeletal muscle (SM) insulin sensitivity, whereas knockdown ameliorated SM insulin resistance. Furthermore, serum and hepatic ERAP1 levels were positively correlated, and recombinant mouse ERAP1 or conditioned medium with high ERAP1 content (CM-ERAP1) attenuated insulin signaling in C2C12 myotubes, and CM-ERAP1 or HFD-induced insulin resistance was blocked by ERAP1 neutralizing antibodies. Mechanistically, ERAP1 reduced ADRB2 expression and interrupted ADRB2-dependent signaling in C2C12 myotubes. Finally, ERAP1 inhibition via global knockout or the inhibitor thimerosal improved insulin sensitivity. Together, ERAP1 is a hepatokine that impairs SM and whole-body insulin sensitivity, and its inhibition might provide a therapeutic strategy for diabetes, particularly for those with SM insulin resistance.

scholarly journals Treatment with an SSRI antidepressant restores hippocampo-hypothalamic corticosteroid feedback and reverses insulin resistance in low-birth-weight rats

2010 ◽  
Vol 298 (5) ◽  
pp. E920-E929 ◽  
Author(s):  
Esben S. Buhl ◽  
Thomas Korgaard Jensen ◽  
Niels Jessen ◽  
Betina Elfving ◽  
Christian S. Buhl ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Birth Weight ◽  
Insulin Sensitivity ◽  
Low Birth Weight ◽  
Mrna Expression ◽  
Hpa Axis ◽  
Whole Body ◽  
Oral Glucose ◽  
Red Muscle ◽  
Hpa Axis Activity

Low birth weight (LBW) is associated with type 2 diabetes and depression, which may be related to prenatal stress and insulin resistance as a result of chronic hypothalamic-pituitary-adrenal (HPA) axis hyperactivity. We examined whether treatment with a selective serotonin reuptake inhibitor [escitalopram (ESC)] could downregulate HPA axis activity and restore insulin sensitivity in LBW rats. After 4–5 wk of treatment, ESC-exposed LBW (SSRI-LBW) and saline-treated control and LBW rats (Cx and LBW) underwent an oral glucose tolerance test or a hyperinsulinemic euglycemic clamp to assess whole body insulin sensitivity. Hepatic phospho enolpyruvate carboxykinase (PEPCK) mRNA expression and red skeletal muscle PKB Ser473phosphorylation were used to assess tissue-specific insulin sensitivity. mRNA expression of the hypothalamic mineralocorticoid receptor was fivefold upregulated in LBW ( P < 0.05 vs. Cx), accompanied by increased corticosterone release during restraint stress and total 24-h urinary excretion ( P < 0.05 vs. Cx), whole body insulin resistance ( P < 0.001 vs. Cx), and impaired insulin suppression of hepatic PEPCK mRNA expression ( P < 0.05 vs. Cx). Additionally, there was a tendency for reduced red muscle PKB Ser473phosphorylation. The ESC treatment normalized corticosterone secretion ( P < 0.05 vs. LBW), whole body insulin sensitivity ( P < 0.01) as well as postprandial suppression of hepatic mRNA PEPCK expression ( P < 0.05), and red muscle PKB Ser473phosphorylation ( P < 0.01 vs. LBW). We conclude that these data suggest that the insulin resistance and chronic HPA axis hyperactivity in LBW rats can be reversed by treatment with an ESC, which downregulates HPA axis activity, lowers glucocorticoid exposure, and restores insulin sensitivity in LBW rats.

scholarly journals Duration of rise in free fatty acids determines salicylate's effect on hepatic insulin sensitivity

2013 ◽  
Vol 217 (1) ◽  
pp. 31-43 ◽  
Author(s):  
Sandra Pereira ◽  
Wen Qin Yu ◽  
María E Frigolet ◽  
Jacqueline L Beaudry ◽  
Yaniv Shpilberg ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Muscle Protein ◽  
Hepatic Insulin Resistance ◽  
Skeletal Muscle Protein ◽  
Protein Levels ◽  
Peripheral Insulin Resistance ◽  
Plasma Ffa ◽  
A Site

We have shown in rats that sodium salicylate (SS), which inhibits IkBa kinase B (IKKB), prevents hepatic and peripheral insulin resistance caused by short-term (7 h) i.v. administration of Intralipid and heparin (IH). We wished to further determine whether this beneficial effect of SS persisted after prolonged (48 h) IH infusion, which better mimics the chronic free fatty acid (FFA) elevation of obesity. Hence, we performed hyperinsulinemic euglycemic clamps with tritiated glucose methodology to determine hepatic and peripheral insulin sensitivity in rats infused with saline, IH, IH and SS, or SS alone. SS prevented peripheral insulin resistance (P<0.05) caused by prolonged plasma FFA elevation; however, it did not prevent hepatic insulin resistance. In skeletal muscle, protein levels of phospho-IkBa were augmented by prolonged IH administration and this was prevented by SS, suggesting that IH activates while SS prevents the activation of IKKB. Markers of IKKB activation, namely protein levels of phospho-IkBa and IkBa, indicated that IKKB is not activated in the liver after prolonged FFA elevation. Phosphorylation of serine 307 at insulin receptor substrate (IRS)-1, which is a marker of proximal insulin resistance, was not altered by IH administration in the liver, suggesting that this is not a site of hepatic insulin resistance in the prolonged lipid infusion model. Our results suggest that the role of IKKB in fat-induced insulin resistance is time and tissue dependent and that hepatic insulin resistance induced by prolonged lipid elevation is not due to an IRS-1 serine 307 kinase.

Impact of PPAR-α induction on glucose homoeostasis in alcohol-fed mice

2013 ◽  
Vol 125 (11) ◽  
pp. 501-511 ◽  
Author(s):  
Valérie Lebrun ◽  
Olivier Molendi-Coste ◽  
Nicolas Lanthier ◽  
Christine Sempoux ◽  
Patrice D. Cani ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Liver Disease ◽  
Insulin Sensitivity ◽  
Alcohol Consumption ◽  
Insulin Signalling ◽  
Liver Steatosis ◽  
Hepatic Insulin Resistance ◽  
Alcoholic Fatty Liver ◽  
Glucose Homoeostasis

Alcohol consumption is a major cause of liver disease. It also associates with increased cardiovascular risk and Type 2 diabetes. ALD (alcoholic liver disease) and NAFLD (non-alcoholic fatty liver disease) share pathological features, pathogenic mechanisms and pattern of disease progression. In NAFLD, steatosis, lipotoxicity and liver inflammation participate to hepatic insulin resistance. The aim of the present study was to verify the effect of alcohol on hepatic insulin sensitivity and to evaluate the role of alcohol-induced steatosis and inflammation on glucose homoeostasis. C57BL/6J mice were fed for 20 days a modified Lieber–DeCarli diet in which the alcohol concentration was gradually increased up to 35% of daily caloric intake. OH (alcohol liquid diet)-fed mice had liver steatosis and inflammatory infiltration. In addition, these mice developed insulin resistance in the liver, but not in muscles, as demonstrated by euglycaemic–hyperinsulinaemic clamp and analysis of the insulin signalling cascade. Treatment with the PPAR-α (peroxisome-proliferator-activated receptor-α) agonist Wy14,643 protected against OH-induced steatosis and KC (Kupffer cell) activation and almost abolished OH-induced insulin resistance. As KC activation may modulate insulin sensitivity, we repeated the clamp studies in mice depleted in KC to decipher the role of macrophages. Depletion of KC using liposomes-encapsuled clodronate in OH-fed mice failed both to improve hepatic steatosis and to restore insulin sensitivity as assessed by clamp. Our study shows that chronic alcohol consumption induces steatosis, KC activation and hepatic insulin resistance in mice. PPAR-α agonist treatment that prevents steatosis and dampens hepatic inflammation also prevents alcohol-induced hepatic insulin resistance. However, KC depletion has little impact on OH-induced metabolic disturbances.

scholarly journals Vasodilator-stimulated phosphoprotein protects against vascular inflammation and insulin resistance

2014 ◽  
Vol 307 (7) ◽  
pp. E571-E579 ◽  
Author(s):  
Andrew M. Cheng ◽  
Norma Rizzo-DeLeon ◽  
Carole L. Wilson ◽  
Woo Je Lee ◽  
Sanshiro Tateya ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Bone Marrow ◽  
Insulin Sensitivity ◽  
Vascular Tissue ◽  
Vascular Inflammation ◽  
Physiological Role ◽  
Whole Body ◽  
Aortic Tissue ◽  
Protective Effects ◽  
Downstream Mediator

Among the pleotropic effects of endothelial nitric oxide (NO) is protection against vascular inflammation during high-fat diet (HFD) feeding. The current work investigated the role of the enzyme vasodilatory-stimulated phosphoprotein (VASP) as a downstream mediator of the anti-inflammatory effect of NO signaling in vascular tissue. Relative to mice fed a low-fat diet (LFD), levels of VASP Ser239 phosphorylation, a marker of VASP activation, were dramatically reduced in aortic tissue of mice with obesity induced by consuming a HFD. As reported previously, the effect of the HFD was associated with increased aortic inflammation, as measured by increased NF-κB-dependent gene expression, and reduced vascular insulin sensitivity (including insulin-stimulated phosphorylation of eNOS and Akt). These effects of the HFD were recapitulated by VASP knockout, implying a physiological role for VASP to constrain inflammatory signaling and thereby maintain vascular insulin sensitivity. Conversely, overexpression of VASP in endothelial cells blocked inflammation and insulin resistance induced by palmitate. The finding that transplantation of bone marrow from VASP-deficient donors into normal recipients does not recapitulate the vascular effects of whole body VASP deficiency suggests that the protective effects of this enzyme are not mediated in immune or other bone marrow-derived cells. These studies implicate VASP as a downstream mediator of the NO/cGMP pathway that is both necessary and sufficient to protect against vascular inflammation and insulin resistance. As such, this work identifies VASP as a potential therapeutic target in the treatment of obesity-related vascular dysfunction.

Increasing endogenous PPARγ ligands improves insulin sensitivity and protects against diet-induced obesity without side effects of thiazolidinediones

2021 ◽  
Author(s):  
Yu-Hua Tseng ◽  
Lee-Ming Chuang ◽  
Yi-Cheng Chang ◽  
Meng-Lun Hsieh ◽  
Lun Tsou ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Insulin Sensitivity ◽  
Side Effects ◽  
Knockout Mice ◽  
Fasting Glucose ◽  
Binding Mode ◽  
Fluid Retention ◽  
Diet Induced Obesity

Abstract Insulin resistance and obesity are pivotal features of type 2 diabetes mellitus. Peroxisome proliferator-activated receptor γ (PPARγ) is a master transcriptional regulator of systemic insulin sensitivity and energy balance. The anti-diabetic drug thiazolidinediones are potent synthetic PPARγ ligands and insulin sensitizers with undesirable side effects including increased adiposity, fluid retention, and osteoporosis, which limit their clinical use. We and others have proved that 15-keto-PGE2 is an endogenous natural PPARγ ligand. 15-keto-PGE2 is catalyzed by prostaglandin reductase 2 (PTGR2) to become inactive metabolites. We found that 15-keto-PGE2 level is increased in Ptgr2 knockout mice. Ptgr2 knockout mice were protected from diet-induced obesity, insulin resistance, and hepatic steatosis without fluid retention nor reduced bone mineral density. Diet-induced obese mice have drastically reduced 15-keto-PGE2 levels compared to lean mice. Administration of 15-keto-PGE2 markedly improved insulin sensitivity and prevented diet-induced obesity in mice. We demonstrated that 15-keto-PGE2 activates PPARγ through covalent binding to its cysteine 285 residue at helix 3, which restrained its binding pocket between helix 3 and β-sheets of the PPARγ ligand binding domain. This binding mode differs from the helix12-dependent binding mode of thiazolidinediones. We further identified a small-molecule PTGR2 inhibitor BPRPT245, which interferes the interaction between the substrate-binding sites of PTGR2 and 15-keto-PGE2. BPRPT245 increased 15-keto-PGE2 concentration, activated PPARγ, and promoted glucose uptake in adipocytes. BPRPT245 also prevented diet-induced obesity, improved insulin sensitivity and glucose tolerance, lowers fasting glucose without fluid retention and osteoporosis. In humans, reduced serum 15-keto-PGE2 levels were observed in patients with type 2 diabetes compared with controls. Furthermore, serum 15-keto-PGE2 levels correlate inversely with insulin resistance and fasting glucose in non-diabetic humans. In conclusion, we identified a new therapeutic approach to improve insulin sensitivity and protect diet-induced obesity through increasing endogenous natural PPARγ ligands without side effects of thiazolidinediones.

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