Metabolic in Vivo Labeling Highlights Differences of Metabolically Active Microbes from the Mucosal Gastrointestinal Microbiome between High-Fat and Normal Chow Diet

Although corroborating data indicate that estrogens influence glucose metabolism through the activation of the estrogen receptor α (ERα), it has not been established whether this pathway could represent an effective therapeutic target to fight against metabolic disturbances induced by a high-fat diet (HFD). To this end, we first evaluated the influence of chronic 17β-estradiol (E2) administration in wild-type ovariectomized mice submitted to either a normal chow diet or a HFD. Whereas only a modest effect was observed in normal chow diet-fed mice, E2 administration exerted a protective effect against HFD-induced glucose intolerance, and this beneficial action was abolished in ERα-deficient mice. Furthermore, E2 treatment reduced HFD-induced insulin resistance by 50% during hyperinsulinemic euglycemic clamp studies and improved insulin signaling (Akt phosphorylation) in insulin-stimulated skeletal muscles. Unexpectedly, we found that E2 treatment enhanced cytokine (IL-6, TNF-α) and plasminogen activator inhibitor-1 mRNA expression induced by HFD in the liver and visceral adipose tissue. Interestingly, although the proinflammatory effect of E2 was abolished in visceral adipose tissue from chimeric mice grafted with bone marrow cells from ERα-deficient mice, the beneficial effect of the hormone on glucose tolerance was not altered, suggesting that the metabolic and inflammatory effects of estrogens can be dissociated. Eventually comparison of sham-operated with ovariectomized HFD-fed mice demonstrated that endogenous estrogens levels are sufficient to exert a full protective effect against insulin resistance and glucose intolerance. In conclusion, the regulation of the ERα pathway could represent an effective strategy to reduce the impact of high-fat diet-induced type 2 diabetes.

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Cardiac mTOR rescues the detrimental effects of diet-induced obesity in the heart after ischemia-reperfusion

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00008.2015 ◽

2015 ◽

Vol 308 (12) ◽

pp. H1530-H1539 ◽

Cited By ~ 22

Author(s):

Toshinori Aoyagi ◽

Jason K. Higa ◽

Hiroko Aoyagi ◽

Naaiko Yorichika ◽

Briana K. Shimada ◽

...

Keyword(s):

Cardiac Function ◽

Ex Vivo ◽

Ischemia Reperfusion ◽

Chow Diet ◽

In Vivo Models ◽

Myocardial Scarring ◽

Diet Induced Obesity ◽

Normal Chow ◽

Normal Chow Diet

Diet-induced obesity deteriorates the recovery of cardiac function after ischemia-reperfusion (I/R) injury. While mechanistic target of rapamycin (mTOR) is a key mediator of energy metabolism, the effects of cardiac mTOR in ischemic injury under metabolic syndrome remains undefined. Using cardiac-specific transgenic mice overexpressing mTOR (mTOR-Tg mice), we studied the effect of mTOR on cardiac function in both ex vivo and in vivo models of I/R injury in high-fat diet (HFD)-induced obese mice. mTOR-Tg and wild-type (WT) mice were fed a HFD (60% fat by calories) for 12 wk. Glucose intolerance and insulin resistance induced by the HFD were comparable between WT HFD-fed and mTOR-Tg HFD-fed mice. Functional recovery after I/R in the ex vivo Langendorff perfusion model was significantly lower in HFD-fed mice than normal chow diet-fed mice. mTOR-Tg mice demonstrated better cardiac function recovery and had less of the necrotic markers creatine kinase and lactate dehydrogenase in both feeding conditions. Additionally, mTOR overexpression suppressed expression of proinflammatory cytokines, including IL-6 and TNF-α, in both feeding conditions after I/R injury. In vivo I/R models showed that at 1 wk after I/R, HFD-fed mice exhibited worse cardiac function and larger myocardial scarring along myofibers compared with normal chow diet-fed mice. In both feeding conditions, mTOR overexpression preserved cardiac function and prevented myocardial scarring. These findings suggest that cardiac mTOR overexpression is sufficient to prevent the detrimental effects of diet-induced obesity on the heart after I/R, by reducing cardiac dysfunction and myocardial scarring.

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Pinealectomy increases thermogenesis and decreases lipogenesis

10.1101/813261 ◽

2019 ◽

Author(s):

Mikyung Kim ◽

So Min Lee ◽

Jeeyoun Jung ◽

Yun Jin Kim ◽

Kyo Chul Moon ◽

...

Keyword(s):

High Fat Diet ◽

Lipid Droplets ◽

Melatonin Receptors ◽

Chow Diet ◽

High Fat ◽

Adipose Tissues ◽

Lipogenic Genes ◽

Sham Surgery ◽

Normal Chow ◽

Normal Chow Diet

AbstractThis study was designed to determine the effects of pineal gland-derived melatonin on obesity by employing rat pinealectomy (Pnx) model. After 10 weeks of high-fat diet (HFD) feeding, rats received sham or Pnx surgery followed by 10 weeks normal chow diet (NCD) feeding. Pnx decreased expressions of melatonin receptors, MTNR1A and MTNR1B, in brown (BAT) and white adipose tissues (WAT). Pnx rats showed increased insulin sensitivity compared with those that received sham surgery. Leptin levels were significantly decreased in the serum of Pnx group. In addition, Pnx stimulated thermogenic genes in BAT whereas attenuated lipogenic genes in WAT and the liver. Histologic analyses revealed marked decreased in the size of lipid droplets and increased expressions of UCP1 in BAT and attenuated lipid droplets in the sized and the number in the liver of Pnx group. In conclusion, these results in the current study suggest that Pnx increases thermogenesis in BAT and decreases lipogenesis in WAT and the liver.

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The antioxidant MnTBAP induces weight loss and enhances insulin sensitivity in mice fed a normal chow diet or a high fat diet

The FASEB Journal ◽

10.1096/fasebj.22.2_supplement.110 ◽

2008 ◽

Vol 22 (S2) ◽

pp. 110-110

Author(s):

Jonathan Brestoff ◽

Thomas H Reynolds

Keyword(s):

Weight Loss ◽

Insulin Sensitivity ◽

High Fat Diet ◽

Chow Diet ◽

High Fat ◽

Normal Chow ◽

Normal Chow Diet

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27-Hydroxycholesterol Promotes Adiposity and Mimics Adipogenic Diet-Induced Inflammatory Signaling

Endocrinology ◽

10.1210/en.2019-00349 ◽

2019 ◽

Vol 160 (10) ◽

pp. 2485-2494 ◽

Cited By ~ 4

Author(s):

Arvand Asghari ◽

Tomonori Ishikawa ◽

Shiro Hiramitsu ◽

Wan-Ru Lee ◽

Junko Umetani ◽

...

Keyword(s):

High Cholesterol Diet ◽

Chow Diet ◽

Sequencing Analysis ◽

Cholesterol Diet ◽

High Cholesterol ◽

High Fat ◽

Adipose Tissues ◽

Inflammatory Gene ◽

Normal Chow ◽

Normal Chow Diet

Abstract 27-Hydroxycholesterol (27HC) is an abundant cholesterol metabolite and has detrimental effects on the cardiovascular system, whereas its impact on adiposity is not well known. In this study, we found that elevations in 27HC cause increased body weight gain in mice fed a high-fat/high-cholesterol diet in an estrogen receptor α–dependent manner. Regardless of diet type, body fat mass was increased by 27HC without changes in food intake or fat absorption. 27HC did not alter energy expenditure in mice fed a normal chow diet and increased visceral white adipose mass by inducing hyperplasia but not hypertrophy. Although 27HC did not augment adipocyte terminal differentiation, it increased the adipose cell population that differentiates to mature adipocytes. RNA sequencing analysis revealed that 27HC treatment of mice fed a normal chow diet induces inflammatory gene sets similar to those seen after high-fat/high-cholesterol diet feeding, whereas there was no overlap in inflammatory gene expression among any other 27HC administration/diet change combination. Histological analysis showed that 27HC treatment increased the number of total and M1-type macrophages in white adipose tissues. Thus, 27HC promotes adiposity by directly affecting white adipose tissues and by increasing adipose inflammatory responses. Lowering serum 27HC levels may lead to an approach targeting cholesterol to prevent diet-induced obesity.

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GPR120 Regulates Pancreatic Polypeptide Secretion From Male Mouse Islets via PLC-Mediated Calcium Mobilization

Endocrinology ◽

10.1210/endocr/bqaa157 ◽

2020 ◽

Vol 161 (10) ◽

Cited By ~ 1

Author(s):

Yu-Feng Zhao ◽

Xiao-Cheng Li ◽

Xiang-Yan Liang ◽

Yan-Yan Zhao ◽

Rong Xie ◽

...

Keyword(s):

Pancreatic Polypeptide ◽

Quantitative Polymerase Chain Reaction ◽

Chow Diet ◽

Specific Cell ◽

Obese Mice ◽

Normal Chow ◽

Mouse Islets ◽

Normal Chow Diet

Abstract The free fatty acid receptor G protein-coupled receptor 120 (GPR120) is expressed in pancreatic islets, but its specific cell distribution and function have not been fully established. In this study, a GPR120-IRES-EGFP knockin (KI) mouse was generated to identify GPR120-expressing cells with enhanced green fluorescence proteins (EGFP). EGFP-positive cells collected from KI mouse islets by flow cytometry had a significantly higher expression of pancreatic polypeptide (PP) evidenced by reverse transcriptase (RT)-quantitative polymerase chain reaction (qPCR). Single-cell RT-PCR and immunocytochemical double staining also demonstrated the coexpression of GPR120 with PP in mouse islets. The GPR120-specific agonist TUG-891 significantly increased plasma PP levels in mice. TUG-891 significantly increased PP levels in islet medium in vitro, which was markedly attenuated by GPR120 small interfering RNA treatment. TUG-891–stimulated PP secretion in islets was fully blocked by pretreatment with YM-254890 (a Gq protein inhibitor), U73122 (a phospholipase C inhibitor), or thapsigargin (an inducer of endoplasmic reticulum Ca2+ depletion), respectively. TUG-891 triggered the increase in intracellular free Ca2+ concentrations ([Ca2+]i) in PP cells, which was also eliminated by YM-254890, U73122, or thapsigargin. GPR120 gene expression was significantly reduced in islets of high-fat diet (HFD)-induced obese mice. TUG-891–stimulated PP secretion was also significantly diminished in vivo and in vitro in HFD-induced obese mice compared with that in normal-chow diet control mice. In summary, this study demonstrated that GPR120 is expressed in mouse islet PP cells and GPR120 activation stimulated PP secretion via the Gq/PLC-Ca2+ signaling pathway in normal-chow diet mice but with diminished effects in HFD-induced obese mice.

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Dietary Curcumin Systemically Maintains Insulin Homeostasis in Diet-Induced Aged Obese Mice via Liver-Pancreas-Brain Axis

Current Developments in Nutrition ◽

10.1093/cdn/nzab033_029 ◽

2021 ◽

Vol 5 (Supplement_2) ◽

pp. 29-29

Author(s):

Yoo Kim ◽

Caio Henrique Mazucanti ◽

Jennifer F. O'Connell ◽

Josephine M. Egan

Keyword(s):

Insulin Clearance ◽

Chow Diet ◽

Obese Mice ◽

High Fat ◽

Insulin Degrading Enzyme ◽

Insulin Levels ◽

High Sugar ◽

Insulin Homeostasis ◽

Normal Chow ◽

Normal Chow Diet

Abstract Objectives Aging is a condition in which we gradually lose the ability to maintain homeostasis due to dysfunction. There continues to be a knowledge gap in implicating how dietary intervention affects the mechanisms delaying or preventing aging-related chronic diseases. Although curcumin (CUR), a natural antioxidant, shows the putative therapeutic properties such as reinstating insulin homeostasis in obese mice, an aging-associated mechanism in which CUR regulates insulin levels largely remains unclear. Thus, the objective of this study is to determine effects of CUR on anti-aging under obese condition mediated by maintaining insulin homeostasis via cross-talk among liver, pancreas and brain. Methods We examine how dietary CUR improves insulin clearance and maintains a proper range of circulating insulin level in the aged diet-induced obesity (DIO) mouse model. Old male C57BL/6J mice were fed a normal chow diet (NCD) or a NCD containing 0.4% (w/w) curcumin (NCD + CUR), a high fat/high sugar diet (HFHSD) or a HFHSD + CUR (N = 7–9 per group) for 16 weeks. Results Old male C57BL/6J mice were fed a normal chow diet (NCD) or a NCD containing 0.4% (w/w) curcumin (NCD + CUR), a high fat/high sugar diet (HFHSD) or a HFHSD + CUR (N = 7–9 per group) for 16 weeks. Mice given HFHSD + CUR had reduced body weight gain (4.7 ± 1.8 vs 7.8 ± 1.6g) and had lower blood insulin levels (2.24 ± 0.3 vs. 1.53 ± 0.3 ng/ml) under fasting conditions compared to mice on HFHSD alone, resulting from significantly improved insulin clearance via upregulation of hepatic insulin-degrading enzyme (IDE) and circulating IDE levels in serum. On the other hand, the expression of IDE gene in hypothalamus was significantly lower in HFHSD + CUR mice (1.3 folds) than HFHSD animals. Obesity induces hyperglycemic condition in brain by higher IDE expression to excessively break down insulin. We also observed significantly smaller islets of Langerhans (4.53 ± 0.72 vs 7.90 ± 0.34 a.u.) in HFSD + CUR fed mice and increased glucagon contents compared to HFS fed mice, indicating less secretion of insulin in pancreas under obese condition. Conclusions The conclusion of this study is that curcumin is a potent, natural therapeutic agent that can systemically regulate insulin levels in a multifaceted manner to protect against insulin resistance in aged mice. Funding Sources Intramural Research Program of NIAThe OTTOGI HAM TAIHO Foundation

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Effects of (−)-Epigallocatechin Gallate (EGCG) on Energy Expenditure and Microglia-Mediated Hypothalamic Inflammation in Mice Fed a High-Fat Diet

Nutrients ◽

10.3390/nu10111681 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1681 ◽

Cited By ~ 16

Author(s):

Jihong Zhou ◽

Limin Mao ◽

Ping Xu ◽

Yuefei Wang

Keyword(s):

High Fat Diet ◽

Epigallocatechin Gallate ◽

Chow Diet ◽

High Fat ◽

Central Nervous System Dysfunction ◽

Stat3 Phosphorylation ◽

Brown Adipose ◽

Normal Chow ◽

Hypothalamic Inflammation ◽

Normal Chow Diet

Obesity is an escalating global epidemic caused by an imbalance between energy intake and expenditure. (−)-Epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, has been reported to be conducive to preventing obesity and alleviating obesity-related chronic diseases. However, the role of EGCG in energy metabolism disorders and central nervous system dysfunction induced by a high-fat diet (HFD) remains to be elucidated. The aim of this study was to evaluate the effects of EGCG on brown adipose tissue (BAT) thermogenesis and neuroinflammation in HFD-induced obese C57BL/6J mice. Mice were randomly divided into four groups with different diets: normal chow diet (NCD), normal chow diet supplemented with 1% EGCG (NCD + EGCG), high-fat diet (HFD), and high-fat diet supplemented with 1% EGCG (HFD + EGCG). Investigations based on a four-week experiment were carried out including the BAT activity, energy consumption, mRNA expression of major inflammatory cytokines in the hypothalamus, nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) phosphorylation, and immunofluorescence staining of microglial marker Iba1 in hypothalamic arcuate nucleus (ARC). Experimental results demonstrated that dietary supplementation of EGCG significantly inhibited HFD-induced obesity by enhancing BAT thermogenesis, and attenuated the hypothalamic inflammation and microglia overactivation by regulating the NF-κB and STAT3 signaling pathways.

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Hepatic HuR protects against the pathogenesis of non-alcoholic fatty liver disease by targeting PTEN

Cell Death and Disease ◽

10.1038/s41419-021-03514-0 ◽

2021 ◽

Vol 12 (3) ◽

Author(s):

Mi Tian ◽

Jingjing Wang ◽

Shangming Liu ◽

Xinyun Li ◽

Jingyuan Li ◽

...

Keyword(s):

Glucose Metabolism ◽

Hepatic Steatosis ◽

Chow Diet ◽

Alcoholic Fatty Liver ◽

Phosphatase And Tensin Homolog ◽

Tensin Homolog ◽

Pten Mrna ◽

Normal Chow ◽

Mice Liver

AbstractThe liver plays an important role in lipid and glucose metabolism. Here, we show the role of human antigen R (HuR), an RNA regulator protein, in hepatocyte steatosis and glucose metabolism. We investigated the level of HuR in the liver of mice fed a normal chow diet (NCD) and a high-fat diet (HFD). HuR was downregulated in the livers of HFD-fed mice. Liver-specific HuR knockout (HuRLKO) mice showed exacerbated HFD-induced hepatic steatosis along with enhanced glucose tolerance as compared with control mice. Mechanistically, HuR could bind to the adenylate uridylate-rich elements of phosphatase and tensin homolog deleted on the chromosome 10 (PTEN) mRNA 3′ untranslated region, resulting in the increased stability of Pten mRNA; genetic knockdown of HuR decreased the expression of PTEN. Finally, lentiviral overexpression of PTEN alleviated the development of hepatic steatosis in HuRLKO mice in vivo. Overall, HuR regulates lipid and glucose metabolism by targeting PTEN.

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