bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Lipid Regulator ANGPTL8 Gene Transcript by Insulin Is Mediated by C/EBPß, and ANGPTL8 Deficiency Improves Glucose Homeostasis in Mice
Authors: ZHANG LU , ABDUL-GHANI MUHAMMAD , DEFRONZO RALPH A. , NORTON LUKE 
Published: June 2018

Angiopoietin-like protein 8 (ANGPTL8) is a novel circulating protein synthesized by the liver and adipose tissue and plays a key role in regulating the plasma lipid profiles. Its expression is regulated acutely by fasting and refeeding in humans and animals. However, the molecular and physiological mechanisms, which regulate its expression, remain largely unknown. In this study, we investigated the regulation of ANPTL8 by insulin and glucose in multiple cellular and animal systems. Interestingly, insulin alone rapidly and dose-dependently increased ANGPTL8 gene expression in both cultured hepatocytes and mature adipocytes, while high glucose combined with insulin presented further stimulation on ANGPTL8 only in adipocytes. In mice, 2-hour euglycemic-hyperinsulinemic and hyperglycemic-hyperinsulinemic clamps markedly stimulated ANGPTL8 mRNA levels in liver to a similar extent. However, only combined hyperglycemia-/hyperinsulinemia caused a significant elevation of ANGPTL8 gene transcript in mouse adipose tissue. These findings imply that distinct pathways are responsible for the effects of insulin and glucose on ANGPTL8 expression in liver and adipose tissue. By cloning the ANGPTL8 gene promoter fragment into a luciferase reporter vector, we discovered that insulin-induced ANGPTL8 gene transcript was mediated by the CCAAT/enhancer-binding protein beta (C/EBPβ) transcription factor, which is likely through Janus Kinase 2 (JAK2) pathway. We also observed that AMPK activation had an inhibitory effect on insulin-induced ANGPTL8 gene expression; this could explain, in part, the low ANGPTL8 levels during fasting. Finally, in mice ANGPTL8 knockout did not alter body weight or food intake compared to wild type littermates, but significantly improved glucose tolerance in diet induced obese mice. This beneficial effect on glucose tolerance most likely is explained by the reduction in serum FFA and triglyceride levels.

Disclosure
L. Zhang: None. M. Abdul-Ghani: None. R.A. DeFronzo: Speaker's Bureau; Self; AstraZeneca, Novo Nordisk Inc.. Advisory Panel; Self; AstraZeneca, Novo Nordisk Inc., Janssen Pharmaceuticals, Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Elcelyx Therapeutics, Inc., Intarcia Therapeutics, Inc.. Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Takeda Pharmaceuticals U.S.A., Inc.. L. Norton: None.
Effects of Simple Carbohydrates on GLP-1 Responses in Gastric Bypass Patients and Matched Controls
Authors: MARTINUSSEN CHRISTOFFER , BOJSEN-MOLLER KIRSTINE N. , DIRKSEN CARSTEN , SVANE MARIA S. , HOLST JENS J. , MADSBAD STEN 
Published: June 2018

Exaggerated postprandial secretion of GLP-1 seems to contribute importantly to the metabolic effects of Roux-en-Y gastric bypass (RYGB). The surgery accelerates nutrient entry to the distal intestine, which is believed to augment GLP-1 secretion. In un-operated individuals, slowly digested carbohydrates are also absorbed in the distal intestine and may accordingly produce greater GLP-1 responses than rapidly absorbed ones.
Our aim was to investigate GLP-1 secretion in response to isomolar (0.1385 mol) oral loads of glucose (glu) and fructose (fru), either given as separate monosaccharides (25 g glu and 25 g fru) or as disaccharides in the form of 47.5 g sucrose (suc) +/- alpha glucosidase inhibition (by acarbose (aca)) or 47.5 g isomaltulose (iso), which is slower digested than suc, on 4 separate days in 10 RYGB patients and 10 controls (CON) matched on BMI, age and sex.
Glu/fru and suc induced similar glucose excursions and responses of C-peptide and GLP-1, the latter being 3-fold greater in RYGB compared to CON. Digestion of iso was slow in comparison with suc in both groups. Mean GLP-1 response (positive iAUC) to iso was ∼50% and ∼160% greater than to suc in RYGB (p=0.11) and CON (p=0.01), respectively. Aca effectively slowed suc digestion in both groups, resulting in lower peak concentrations of glucose (RYGB: 9.3 vs. 6.7 mmol/l, CON: 7.7 vs. 6.6 mmol/l) and C-peptide (RYGB: 2762 vs. 1341 pmol/l, CON: 2367 vs. 1520 pmol/l) compared with suc alone (p&lt;0.01). Aca diminished mean suc stimulated GLP-1 secretion by ∼50% in RYGB (p&lt;0.01), but this effect was absent in CON.
The slowly absorbed disaccharide isomaltulose elicits a greater GLP-1 response than sucrose. The same effect is not evident when digestion of sucrose is inhibited by acarbose, which in RYGB diminishes sucrose induced GLP-1 secretion. Understanding the digestive processes involved in carbohydrate induced GLP-1 release after gastric bypass is an important step towards mimicking the effects of the surgery by pharmacological means.

Disclosure
C. Martinussen: None. K.N. Bojsen-Moller: None. C. Dirksen: None. M.S. Svane: None. J.J. Holst: Advisory Panel; Self; Novo Nordisk A/S. Board Member; Self; Zealand Pharma A/S. Speaker's Bureau; Self; Merck Sharp & Dohme Corp., AstraZeneca. Research Support; Self; Danish Diabetes Academy, Novo Nordisk Foundation. Other Relationship; Self; Antag Therapeutics. Other Relationship; Spouse/Partner; Antag Therapeutics. S. Madsbad: Advisory Panel; Self; AstraZeneca. Speaker's Bureau; Self; AstraZeneca. Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Advisory Panel; Self; Boehringer Ingelheim Pharmaceuticals, Inc.. Speaker's Bureau; Self; Eli Lilly and Company, Eli Lilly and Company. Advisory Panel; Self; Merck Sharp & Dohme Corp., Sanofi-Aventis, Novo Nordisk A/S. Speaker's Bureau; Self; Novo Nordisk A/S. Research Support; Self; Novo Nordisk A/S.
Forced Expressed GLP-1R Attenuates Prostate Cancer Growth
Authors: SHIGEOKA TORU , NOMIYAMA TAKASHI , KAWANAMI TAKAKO , HAMAGUCHI YURIKO , TANAKA TOMOKO , YANASE TOSHIHIKO 
Published: June 2018

Incretin therapy is one of the most popular treatment for type 2 diabetes. GLP-1R agonist has received much attention, because of its tissue protective effects beyond glycemic control. We have previously reported anti-prostate and anti-breast cancer effect of GLP-1R agonist Exendin-4(Ex-4) (Diabetes 2014, PLOS ONE 2015, Endocrinology 2017). In our previous report, the attenuation of cancer cell proliferation was depending on GLP-1R expression, and Ex-4 did not attenuate cell proliferation in ALVA-41, prostate cancer cell line without GLP-1R expression. Then, we next examined anti-prostate cancer effect in ALVA-41 forced expressed GLP-1R using lentivirus vector (ALVA-41-GLP-1R). We confirmed abundant GLP-1R expression in ALVA-41-GLP-1R using RT-PCR and immunohistochemistry. Ex-4 significantly decreased the proliferation of ALVA-41-GLP-1R in a dose dependent manner, but not in ALVA-41 transfected with control vector (ALVA-41-control), suggesting that forced expressed GLP-1R was intact. In the growth curve, cell number of ALVA-41-GLP-1R was significantly decreased compared with ALVA-41-control. BrdU assay revealed that cell proliferation was attenuated in ALVA-41-GLP-1R, and S Phase entry was inhibited in cell cycle distribution. Further, p27(CDKN1B) expression was increased in ALVA-41-GLP-1R compared with ALVA-41-control in Western Blotting analysis. These data suggest that forced expressed GLP-1R attenuated prostate cancer cell proliferation via inhibiting cell cycle progression.

Disclosure
T. Shigeoka: None. T. Nomiyama: Research Support; Self; MSD K.K., Sanofi-Aventis, Boehringer Ingelheim Pharmaceuticals, Inc., Takeda Pharmaceuticals, Japan. T. Kawanami: None. Y. Hamaguchi: None. T. Tanaka: None. T. Yanase: Research Support; Self; MSD K.K., Boehringer Ingelheim Pharmaceuticals, Inc., Takeda Pharmaceuticals, Japan.
The Role of Visceral Adipocytes in Adrenergically Stimulated Adiponectin Secretion
Authors: MUSOVIC SALIHA , NGUYEN SANDRA , OLOFSSON CHARLOTTA S. 
Published: June 2018

Adiponectin is a white adipocyte hormone with insulin sensitizing properties. Correlations have been observed between adiponectin and different adipose tissue depots where serum adiponectin levels exhibit a negative relationship to visceral fat mass (VAT). Individuals with increased VAT have a greater risk for developing type 2 diabetes. We have previously shown that catecholamines stimulate acute adiponectin release from subcutaneous adipocytes via adrenergic beta-3-receptors (β3ARs) and Epac1. We further showed that this adrenergic stimulation was abolished in obesity/diabetes due to reduced levels of both β3ARs and Epac1. Here we aim to study the adrenergically stimulated adiponectin secretion in visceral adipocytes in health and in metabolic disease. Results obtained by ELISA revealed that epinephrine (EPI) and CL316243 (CL;β3AR-agonist) stimulated adiponectin release to a similar degree (∼2 fold) in primary visceral mouse adipocytes during 30 minutes incubation. The stimulatory effect of EPI was inhibited by Epac antagonist ESI-09 (P&lt;0.05). Studies using visceral adipocytes isolated from obese/diabetic mice demonstrated that adiponectin release could still be stimulated with EPI and CL (∼1.5 fold) although at a significantly lower magnitude compared to control mice (P&lt;0.001). RT-qPCR results showed a high expression of β3AR as well as Epac1 in adipocytes isolated from control mice. In adipocytes isolated from obese/diabetic mice there was no change in expression of β3AR but an increase of Epac1 (P&lt;0.001). Our results propose that acute adiponectin release in visceral adipocytes is regulated through activation of β3AR and Epac1. It is an interesting finding that VAT adipocytes which are connected to several metabolically active organs largely maintain adrenergically stimulated adiponectin release in obesity/diabetes.

Disclosure
S. Musovic: None. S. Nguyen: None. C.S. Olofsson: None.
Insulin-Like Growth-Factor Axis Collectively Identifies Pre–Type 1 Diabetes
Authors: SHAPIRO MELANIE , WASSERFALL CLIVE , SCHULTZ ANDREW R. , MCGRAIL SEAN M. , HALLER MICHAEL J. , SCHATZ DESMOND , ATKINSON MARK A. , BRUSKO TODD M. 
Published: June 2018

Autoantibodies (AAb) against beta cell antigens are useful biomarkers for type 1 diabetes (T1D) prediction; however, staging of pre-T1D requires lengthy and invasive glucose tolerance testing. A need exists for additional serum biomarkers reflective of metabolic and immunologic dysregulation to test concurrently with AAb. The insulin-like growth factor (IGF) family, consisting of IGF1 and IGF2, has been shown to promote insulin action and possess immunoregulatory properties. Their activity is regulated by at least seven IGF binding proteins (IGFBPs). We hypothesized that IGF1 and IGF2 levels or bioavailability are reduced during T1D development. Total serum IGF1, IGF2, and IGFBP1-7 levels were measured in an age-matched (12.0 ± 3.7 years), cross-sectional cohort of AAb negative (AAb-) controls (CTRL) (n=74); AAb- first-degree relatives (AAb- FDR, n=55); FDR positive (AAb+ FDR) for one (n=23) or multiple (n=26) of GAD65, IA-2, or ZnT8 AAbs; new onset (NO) T1D patients (n=63, duration 1.0 ± 0.7 months); and established T1D patients (n=68, duration 4.4 ± 3.7 years). IGF1 and IGF2 levels were significantly lower in AAb+ FDR compared to AAb- FDR (204 ± 117 vs. 346 ± 160 ng/mL, p&lt;0.001; 701 ± 496 vs. 1054 ± 721 ng/mL, p&lt;0.01). Lower IGF1 levels were noted in single AAb+ FDR (183 ± 112 ng/mL, p&lt;0.0001), while lower IGF2 levels remained significant in multiple AAb+ FDR only (686 ± 535 ng/mL, p&lt;0.05). IGFBP1 levels were increased in AAb+ FDR compared to AAb- FDR (3.6 ± 3.2 vs. 1.8 ± 1.7 ng/mL, p&lt;0.01), and this was apparent in single AAb+ FDR (4.5 ± 4.0 ng/mL, p&lt;0.001). IGFBP7 levels were significantly lower in multiple AAb+ FDR as compared to AAb- FDR (79 ± 21 vs. 95 ± 22 ng/mL, p&lt;0.05). Additionally, we established a multiple logistic regression model evaluating age, IGFs, and IGFBPs (IGFBP1, -3, and -7), which could effectively discriminate AAb+ FDR from CTRL (AUC = 0.84). These data suggest a dysregulated IGF axis is present prior to symptomatic T1D and may provide new biomarkers to improve disease prediction.

Disclosure
M. Shapiro: None. C. Wasserfall: None. A.R. Schultz: None. S.M. McGrail: None. M.J. Haller: None. D. Schatz: None. M.A. Atkinson: Other Relationship; Self; Patent Issued. T.M. Brusko: Stock/Shareholder; Self; OneVax, LLC. Advisory Panel; Self; Caladrius Biosciences, Inc.. Consultant; Self; Merck & Co., Inc., Sanofi-Aventis.
Cross-Sectional Associations between Drinking Bottled Water and Prediabetes/Diabetes
Authors: JOSHIPURA KAUMUDI J. , TRAK MARIA A. , MUÑOZ-TORRES FRANCISCO J. 
Published: June 2018

Dietary recommendations for healthy adults include adequate hydration (males: 125 ounces/day, females: 91 ounces/day) from drinking water, other beverages, and water contained in food. Bottled water sales in U.S. exceeded 11.7 billion gallons in 2015 (36.5 gallons per capita). Low water intake, as well as some chemicals in water sources, are associated with hyperglycemia. However, the association between drinking water sources and hyperglycemia/diabetes has not been studied. In a cohort of overweight/obese Puerto Ricans, we evaluated the association between water sources (bottled and filtered compared to tap water) and prediabetes/diabetes. In 2014-2016, 1023 participants reported their primary source of water as bottled (52%), filtered (25%) and tap (23%); diabetes status was assessed using ADA criteria for fasting and 2-hour post load glucose, and HbA1c. Logistic regression models controlled for age, gender, waist circumference, smoking, alcohol intake, physical activity, and hypertension. Bottled water consumers (compared to tap water) had higher prediabetes (OR=1.43; 95% CI: 1.02, 2.01), and diabetes (OR=1.93; 95% CI: 1.08, 3.46). Further controlling for amount of water, sugar sweetened beverages, or canned food and drinks did not change the associations, but controlling for education or income strengthened the association with diabetes. Results were stronger when restricted to San Juan city residents (43%): prediabetes (OR=1.68; 95% CI: 1.01, 2.79), and diabetes (OR=4.05; 95% CI: 1.48, 11.1). Filtered water users had somewhat higher prediabetes/diabetes (OR=1.38; 95% CI: 0.93, 2.04) compared to tap water users. Results suggest that drinking bottled water may be associated with higher prevalence of diabetes compared to tap water, potentially mediated by endocrine disruptors in plastic bottles. We cannot determine time sequence or causality, given the cross-sectional analyses. The impact of water sources on diabetes risk needs to be further evaluated longitudinally.

Disclosure
K.J. Joshipura: None. M.A. Trak: None. F.J. Muñoz-Torres: None.
Exendin-4, but Not Oleoylethanolamide, Promotes Host-Mediated Alterations to the Gut Microbiome during Weight Loss
Authors: BROWN JACOB , SHARMA VANDANA , TRAN DAVID , PETERSON SCOTT N. , AYALA JULIO , BROWN JACOB 
Published: June 2018

Gut-derived molecules like glucagon-like peptide-1 (GLP-1) and oleoylethanolamide (OEA) are prime targets for developing more effective obesity therapeutics due to their weight loss action. Hypophagia is commonly cited as the mechanism by which OEA and Exendin-4 (Ex4), a GLP-1 receptor agonist, reduce body weight. However, we recently showed in diet-induced obese (DIO) mice that the hypophagic action of Ex4 and OEA is transient and that weight loss continues even as food intake returns to pre-treatment levels. This was associated with increased energy expenditure (EE) in Ex4-, but not OEA-treated, mice. Given the emerging role for the gut microbiome as a regulator of energy balance, we hypothesized that the long-term, food intake-independent weight loss elicited by Ex4 is associated with alterations in the gut microbiome. In vivo and in vitro experiments coupled with 16S analysis were used to determine the effect of chronic Ex4 and OEA on the gut microbiome during weight loss. Male, DIO C57Bl/6J mice (60% high-fat diet for 15 weeks) were dosed 2x daily with Vehicle, OEA (5mg/kg) or Ex4 (100µg/kg) for 7 days. Fecal pellets were collected pre- and post-treatment for 16S analysis. Ex4 caused a change (p&lt;0.05) in 11 bacterial species, including a 5.6-fold increase in L. johnsonii, a bacteria that has been shown to improve metabolic outcomes in DIO models. In contrast, though OEA reduced body weight, OEA treatment had relatively little effect on the microbiome. To determine whether Ex4 and OEA directly alter the gut bacteria profile, we cultured gut bacteria isolated from DIO mice and treated the cultures with Vehicle, OEA (10µM), or Ex4 (10nM) for 24 hours. 16S analysis of in vitro cultures revealed no change in bacteria profiles for either treatment. These results suggest that Ex4 indirectly alters the gut microbiome to promote weight loss. Future experiments will determine if microbiome alterations contribute to the Ex4-mediated elevation in EE and improvements in metabolic outcomes.

Disclosure
J. Brown: None. V. Sharma: None. D. Tran: None. S.N. Peterson: None. J. Ayala: None. J. Brown: None.
Iron Downregulates Leptin by Decreasing CREB O-GlcNAc Modification and CREB Occupancy of the Leptin Promoter
Authors: LIU JINGFANG , GAO YAN , LORENZO FELIPE , SINK SANDY T. , MCCLAIN DON 
Published: June 2018

Modification of proteins by O-linked N-acetylglucosamine (O-GlcNAc) serves as a nutrient-dependent signal to regulate transcription of the leptin gene. Recently we reported that increased levels of iron, which are also a risk factor for type 2 diabetes, down regulate leptin in mice fed high iron diets (2000 mg/kg) or in 3T3L1 cells treated with iron. Iron increased cyclic AMP-dependent response element binding protein (CREB) phosphorylation and its occupancy at inhibitory sites in the leptin promoter, but without demonstrable increases in CREB kinase activities. We now demonstrate that nutrient- and iron-dependent regulation of leptin are linked through O-GlcNAc modification of CREB. CREB O-GlcNAc modification was decreased in mice fed high iron, and this was associated with 54±7% and 44±9% reductions in recruitment to its two sites in the leptin promoter as analyzed by ChIP (p&lt;0.05). Increasing levels of O-GlcNAc through targeted deletion of the O-GlcNAcase (OGA) gene in adipocytes increased adipose leptin mRNA expression by 86±12% (p&lt;0.05) in mice fed a low-normal iron diet (35 mg/kg) and partially rescued the effect of high iron (35±3%, p&lt;0.05). Similar effects were seen in serum leptin levels: High iron caused a 72% decrease and OGA deletion resulted in a rescue of 34%. Treatment of 3T3L1 cells with iron decreased expression of a leptin reporter plasmid by 45±4% and glucosamine, which bypasses the rate-limiting step in synthesis of UDP-GlcNAc, the substrate for O-GlcNAcylation, increased protein O-GlcNAc and fully rescued (106±5%) the effect of high iron (p&lt;0.001 for both). Although iron also decreased global levels of protein O-GlcNAc modification, mRNA levels of the enzymes that control the modification, namely O-GlcNAc transferase and OGA, were unchanged. We conclude that adipose tissue integrates cellular nutrient status and tissue iron levels to control the regulation of leptin, through regulation of O-GlcNAc modification of the transcription factor CREB.

Disclosure
J. Liu: None. Y. Gao: None. F. Lorenzo: None. S.T. Sink: None. D. McClain: None.
Peripheral Melanocortin 3 Receptor (MC3R) Regulates Hepatic Autophagy in Obesity
Authors: JUN JOO YUN , SEO ARNOLD Y. , PATEL TUSHAR P. , UHLMAN ANDREW J. , LEVI NOAH J. , ROBERSON ROBIN , YANOVSKI JACK A. 
Published: June 2018

We have previously reported homozygosity for two MC3R SNPs (C17A+G241A) that partially inactive MC3R increases adiposity in humans and mouse models. However, the precise mechanisms by which hypoactive MC3R alters metabolic homeostasis remain unclear. Given the essential role of hepatic autophagy in cellular mechanisms of obesity, we hypothesized that diminished peripheral MC3R activity leads to hepatic lipid accumulation by interfering with autophagy, leading to steatosis. We used knock-in mouse models that carry either homozygous human “wild type” (MC3RhWT/hWT) or “double mutant” MC3R (C17A+G241A, MC3RhDM/hDM). We studied hepatic autophagic pathways with biochemical/imaging analysis in wild type Mc3r (C57/BL6) and MC3RhWT/hWT as controls (WT mice), and in MC3RhDM/hDM, and mice lacking Mc3r (Mc3r-/-) which each have greater fat mass and hepatic triglycerides. We first demonstrated the MC3R specific agonist D-trp-γ-MSH induced LC3II (a marker of autophagosome formation) in hepatocytes from WT, but not Mc3r-/- or MC3RhDM/hDM mice. Interestingly D-trp-γ-MSH also induced TFEB (a master regulator of lysosomal biogenesis) translocation from cytosol to nucleus in TFEB-overexpressed NIH-3T3 cells, indicating MC3R may regulate autophagy by affecting TFEB signaling. Overnight fasting induced liver LC3II expression in WT mice, but not in MC3RhDM/hDM or Mc3r-/-; rather, basal LC3II was upregulated even in the fed state for the latter two genotypes. Hepatocytes from MC3RhDM/hDM or Mc3r-/- failed to increase autophagic flux with starvation or with the presence of chloroquine, suggesting MC3R may play a role in the regulation of autolysosomal degradation under the control of TFEB. Electron microscopy analysis of liver sections further demonstrated MC3RhDM/hDM mice exhibited fewer lipid droplet-associated autophagosomes compared to MC3RhWT/hWT mice. These data suggest MC3R plays an important peripheral role for the regulation of hepatic autophagy that is targeted to lipids.

Disclosure
J. Jun: None. A.Y. Seo: None. T.P. Patel: None. A.J. Uhlman: None. N.J. Levi: None. R. Roberson: None. J.A. Yanovski: Research Support; Self; Rhythm Pharmaceuticals Inc., Zafgen.