bluuebunny/crossref_metadata_2025 huggingface dataset:
Deficiency in Absent in Melanoma (AIM) 2, an Innate Immunity Protein, Is Associated with Hepatic Steatosis
Authors: GONG ZHENWEI , JIANG RUIHUA , SU KAI , GOETZMAN ERIC , DONG HENRY , MUZUMDAR RADHIKA
Published: June 2018

Absent in Melanoma (AIM) 2, an HIN-200 domain family interferon inducible gene, is a cytosolic sensor for double-stranded DNA, forms the AIM2 inflammasome, and is a tumor suppressor gene. Lack of AIM2 increases the risk for cancers including liver cancer. We had earlier shown that mice with whole body deletion of AIM2 (AIM2-/-) exhibit increased body weight and total fat mass (without change in lean mass), visceral and subcutaneous adiposity, elevated fasting glucose and impaired glucose tolerant test without significant change in food intake. To assess the effects of AIM2-/- on liver, we analyzed liver weight, gene expression and protein levels of key players of hepatic lipid metabolism in female wild type (WT) and AIM2-/- mice (14-month-old, n=7/group) on chow diet. Fatty acid oxidation in liver was determined by incubating 14C-palmitate with liver lysate, and trapping and quantifying the 14CO2 generated from the 14C-palmitate. We found that liver was enlarged in AIM2-/- mice compared to WT controls (liver weight 1.25±0.03 vs. 1.62±0.09 g, p<0.01 and liver/body weight 0.037±0.001 vs. 0.042±0.002 in WT and AIM2-/- respectively, p=0.02). Histological examination demonstrated significantly increased lipid deposition in the liver of AIM2-/- mice. Expression levels of lipogenic genes, such as ACC1 (4 fold), ACC2 (3.2 fold), PPARγ (2.8 fold), C/EBPα (2.4 fold), CD36 (2.4 fold), Fasn (4.3 fold) and SREBP-1c (3.8 fold) were significantly increased in AIM2-/- mice; increases in lipogenic gene expression in the liver are likely due to the phosphorylation and nuclear localization of STAT3. Fatty acid oxidation was not affected in liver of AIM2-/- mice (22.8±2.4 vs. 25±3.9 pmoles/ug/hr, p=0.52). Taken together, our data provides strong evidence that AIM2 is a regulator of hepatic fat, thereby providing a novel target for treatment of NALFD. AIM2 is a novel link between innate immunity, cancer and obesity.

Disclosure

Z. Gong: None. R. Jiang: None. K. Su: None. E. Goetzman: None. H. Dong: None. R. Muzumdar: None.
A Novel Role of Growth Differentiation Factor 3 for the Regulation of Muscle Metabolism
Authors: HAYS TRISTAN T. , PATSALOS ANDREAS , HAMMERS DAVID , HUANG CHUNTENG , RESTREPO ISABELLA , HAJIAN MATINE , AYALA JULIO , NAGY LASZLO
Published: June 2018

Insulin resistance has become a major global health problem, and current insulin sensitization treatments have the unfortunate effect of also increasing adiposity. One solution to mitigate these side effects would be to selectively stimulate skeletal muscle metabolism to reduce fasting glucose levels and improve insulin sensitivity. Previous studies have described growth differentiation factor 3 (GDF3) as an adipokine, however our recent studies have identified GDF3 as a macrophage derived factor that stimulates myoblast fusion and promotes muscle regeneration. Thus, we hypothesize that GDF3 might also stimulate myocyte metabolism and skeletal muscle insulin sensitivity. We first assessed whether recombinant GDF3 treatment can stimulate glucose uptake in vitro. Differentiated C2C12 myotubes were treated with rGDF3 and [H3] 2-deoxy-D-glucose uptake was found to be increased upon GDF3 treatment. Next, we tested whether GDF3 could stimulate insulin sensitivity in vivo. GDF3 was adenovirally overexpressed in mice fed a high fat diet for 8 weeks and insulin sensitivity was assessed by insulin tolerance tests. GDF3 overexpression reduced fasting glucose levels and also demonstrated a tendency for improved insulin tolerance. Collectively, these data suggest that GDF3 could act as a potential insulin sensitizing agent and provide mechanistic insights into skeletal muscle glucose regulation.

Disclosure

T.T. Hays: None. A. Patsalos: None. D. Hammers: None. C. Huang: None. I. Restrepo: None. M. Hajian: None. J. Ayala: None. L. Nagy: None.
Identification of Warm-Sensitive Neurons in the Hypothalamic Preoptic Area as Powerful Regulators of Glucose Homeostasis
Authors: DEEM JENNIFER D. , OGIMOTO KAYOKO , VELASCO KEVIN R. , DAMIAN VINCENT , KNIGHT ZACHARY , SCHWARTZ MICHAEL W. , MORTON GREGORY J.
Published: June 2018

Inhibition of warm sensitive neurons (WSN) in the hypothalamic preoptic area (POA) has been suggested to play a key role in the thermogenic response to cold exposure. As this response is enabled by a marked increase of insulin sensitivity in thermogenic tissues, we hypothesized that WSN inhibition mediates the metabolic as well as the thermogenic response, and therefore that WSN activation would have the opposite effects. To test this hypothesis, we utilized pharmacogenetic technology to activate or inhibit a recently identified subpopulation of POA WSN defined by their expression of the neuropeptide, Pacap, using the drug clozapine-N-oxide (CNO). We report that, as predicted, pharmacogenetic activation of this POA WSN population reduces energy expenditure (EE) (Sal vs. CNO: 0.32±0.10 vs. 0.21±0.02 kcal/hour; p<0.05) and core temperature (Tc) (Sal vs. CNO: 35.4±0.1 vs. 30.4±0.1°C; p=0.0001), while inhibition had the opposite effect (EE: Sal vs. CNO: 0.25±0.03 vs. 0.26±0.03 kcal/hour; Tc: Sal vs. CNO: 35.8±0.1 vs. 36.4±0.2°C; p<0.05). The response to pharmacogenetic activation of POA Pacap+ neurons was quite long-lived (∼2-3 days) and was accompanied by severe glucose intolerance both 1 hour and 24 hour following CNO relative to vehicle treatment (glucose AUC: 3610±1216 for saline vs. 23985±2742 for 1 hour CNO vs. 28459±2411 vs. 24 hour CNO au; p<0.05 vs. saline). Moreover, this marked impairment of glucose tolerance occurred even after a compensatory increase of glucose-induced insulin secretion at the 24 hour time point (Plasma insulin (t=30): 0.42±0.10 for saline vs. 0.45±0.10 ng/mL for 1 hour CNO vs. 1.05±0.20 ng/mL for 24 hour CNO; p=ns). However, despite significant increases in Tc, acute inhibition of POA Pacap+ neurons did not improve glucose tolerance, possibly due to compensation by other WSN populations activated by the thermogenic response. We conclude that POA Pacap+ neurons constitute a subset of WSN that exert profound, previously unrecognized effects on glucose homeostasis.

Disclosure

J.D. Deem: None. K. Ogimoto: None. K.R. Velasco: None. V. Damian: None. Z. Knight: None. M.W. Schwartz: Consultant; Self; Novo Nordisk A/S. Research Support; Self; Novo Nordisk A/S. G.J. Morton: None.
Mediating Role of Acculturation and Lifestyle Behaviors on Cardiometabolic Risks among Asian Indians in the United States
Authors: JOSEPH NITHA MATHEW , MISRA RANJITA , WANG JING , CRON STANLEY , RAMASWAMY PADMAVATHY
Published: June 2018

Background: Asian Indians are the 2nd largest Asian immigrants in the U.S. and have higher rates of diabetes, metabolic syndrome, and cardiovascular disease when compared to the general U.S. population and other immigrant groups. Acculturation levels influence the lifestyle practices and studies have reported acculturated individuals have increased risks for chronic diseases.

Aim: Hence, this study explored the mediating role of lifestyle behaviors (physical activity and dietary behavior) between acculturation and cardiometablic risk factors among Asian Indians using the DIA (Diabetes in Indian Americans) national study.

Methods: The sample comprised 1038 randomly selected adult Asian Indians in seven U.S. sites (mean age was 48.54 ±12.8 years). Acculturation was assessed using the English proficiency scores from the Acculturation Scale for Southeast Asians and dietary behavior and physical activity were calculated from the subscales of Health Promotion Lifestyle Profile II. Path analyses with bootstrap methods were used to explore if physical activity or dietary behavior mediates the relationship between acculturation and cardiometabolic risk factors (HbA1c, fasting blood glucose levels, Body Mass Index, systolic and diastolic blood pressure, and lipid profiles [HDL, LDL, total cholesterol, and triglycerides]).

Results: Dietary behavior significantly mediated the relationship between acculturation and HbA1C (β=0.004, p = .047) and physical activity mediated the relationship between acculturation and HDL (β=0.08, p = .011). All other mediation models were not significant (p>.05) based on the nonsignificant indirect effects detected in the models.

Conclusion: Culturally specific dietary education and physical activity interventions for this high risk ethnic group may have potential to reduce cardiometabolic risks. Results provide firm basis for educational program.

Disclosure

N. Mathew Joseph: None. R. Misra: None. J. Wang: None. S. Cron: None. P. Ramaswamy: None.
GCN5l1 Modulates Cross Talk between Mitochondria and Cell Signaling to Regulate Fox01 Stability and Gluconeogenesis
Authors: WANG LINGDI
Published: June 2018

The mitochondrial enriched GCN5-like 1 (GCN5L1) protein has been shown to modulate mitochondrial protein acetylation, mitochondrial content and mitochondrial retrograde signaling. Here we show that hepatic GCN5L1 ablation reduces fasting glucose levels and blunts hepatic gluconeogenesis without affecting systemic glucose tolerance. PEPCK and G6Pase transcript levels are downregulated in hepatocytes from GCN5L1 liver specific knockout mice and their upstream regulator, FoxO1 protein levels are decreased via proteasome-dependent degradation and via reactive oxygen species mediated ERK-1/2 phosphorylation. ERK inhibition restores FoxO1, gluconeogenic enzyme expression and glucose production. Reconstitution of mitochondrial-targeted GCN5L1 blunts mitochondrial ROS, ERK activation and increases FoxO1, gluconeogenic enzyme expression and hepatocyte glucose production. We suggest that mitochondrial GCN5L1 modulates post-translational control of FoxO1, regulates gluconeogenesis and controls metabolic pathways via mitochondrial ROS mediated ERK activation. Exploring mechanisms underpinning GCN5L1 mediated ROS signaling may expand our understanding of the role of mitochondria in gluconeogenesis control.

Disclosure

L. Wang: None.
Collagen VI-Derived Endotrophin Promotes Hepatic Apoptosis, Inflammation, and Fibrosis in Chronic Liver Disease
Authors: KIM MIN , PARK JIYOUNG
Published: June 2018

Type VI collagen alpha3 chain (Col6a3) is a biomarker for hepatic fibrosis and poor prognosis of hepatocellular carcinoma (HCC), but its function in liver pathology remains unknown. Analysis of human HCC patients revealed that elevated mRNA levels of COL6A3 in tumor-proximal liver regions were associated with poor prognosis in HCC patients. Here, we show that endotrophin (ETP), a cleaved Col6a3 fragment, significantly augmented hepatocyte apoptosis, inflammation, and fibrosis in chemically induced chronic liver disease models by utilizing either CCl4 or DEN in the background of hepatocyte-specific ETP transgenic mice, nevertheless ETP per se showed a limited phenotypic changes in liver tissues. Notably, both hepatocytes and non-parenchymal cells in liver tissues were responsible for an increase of ETP levels in chronic liver injuries, and inhibition of ETP with neutralizing antibodies (10B6) ameliorated hepatic apoptosis, inflammation, and fibrosis in these cells. Our results mechanistically implicate ETP as a necessary component for sustained JNK activation in early stage of chronic liver diseases; thus, ETP-JNK axis could be a promising therapeutic target, particularly in individuals with high local levels of COL6A3 in chronic liver disease.

Disclosure

M. Kim: None. J. Park: None.
SGLT Inhibitors Enhance Endogenous Glucose Productions (EGP) in a Preclinical Animal Model
Authors: HUANG SHUJUAN , CAI DONGFENG , YUE ZENGPU , YAN HUANG , ZHOU ZHOU , FU XINFA , WANG HONGMEI , TAO YI , HWA JOYCE J.
Published: June 2018

Aim: SGLT inhibitors was found to paradoxically enhance EGP in type 2 diabetes patients, while reduce EGP in diabetic mice during hyperinsulinemic-euglycemic clamp. In this study, we assess acute and 7-day effects of SGLT inhibitors on EGP in rats by 13C-glucose tracer dilution method to identify a translational rodent model.

Method: SD rats aged 7 weeks were assigned to 3 groups (n=6 each), vehicle, LX4211 (10 mg/kg) and canagliflozin (10 mg/kg). On day 1, rats were fasted for 3 hours and dosed with SGLT inhibitors, LX4211 or canagliflozin before a 13C-glucose IV injection (25 mg/kg) 2 hour post drug administration. Blood were collected at 0, 5, 15, 30, 45, 60, 75, 90, 120, and 150 minutes time points. Plasma 13C-glucose and 12C-glucose levels were detected by LC/MS. EGP was calculated by multiplying fractional glucose turnover rate by pool size. After washout and the same 18 rats were dosed for 7 days, EGP were assessed on day 7.

Results: 13C--glucose IV injection after acute LX4211 and canagliflozin dosing did not significantly changed plasma glucose concentration over time, but led to a rapid rise in plasma 13C-glucose enrichment followed by a time-dependent decrease of 13C-glucose enrichment. The fractional glucose turnover rate and EGP were 3.14±0.35 (SD) percent and 6.28±0.70 (SD) mg.kg-1.minutes-1 in vehicle group. Single dose of LX4211 and canagliflozin significantly increased EGP by 27.5% and 57.1%, respectively. After 7-days of treatment, the fractional glucose turnover and EGP were 3.30±0.28 (SD) percent and 6.59±0.56 (SD) mg.kg-1.minutes-1 in vehicle group, which was highly consistent to the previous EGP measurement. Moreover, 7 days treatment of LX4211 and canagliflozin significantly elevated EGP by 24.8% and 33.4%, respectively.

Conclusion: This study demonstrated that SGLT inhibitors can increase EGP in animal model as in type 2 diabetes patients. Detecting EGP using 13C-glucose tracer dilution method may facilitate the discovery of novel SGLT inhibitors with differential effects on EGP.

Disclosure

S. Huang: None. D. Cai: None. Z. Yue: None. H. Yan: None. Z. Zhou: None. X. Fu: None. H. Wang: None. Y. Tao: None. J.J. Hwa: None.
Vitamin E Supplementation during Nonalcoholic Steatohepatitis (NASH) Pathogenesis in High-Sucrose, High-Fat-Fed Genetically Obese Mice
Authors: HASENOUR CLINTON , YOUNG JAMEY
Published: June 2018

Nonalcoholic fatty liver disease is characterized by dysregulated hepatic oxidative metabolism which may progress to a state of elevated inflammation and fibrosis (NASH). The lipophilic antioxidant vitamin E (VitE) has shown promise as an effective strategy for treating NASH in some clinical trials. Here we tested whether dietary VitE supplementation is sufficient to prevent NASH development and mitigate aberrant glucose and oxidative liver metabolism during overnutrition. Hyperphagic, melanocortin-4-receptor deficient mice (MC4R-/-) were fed a chow, western diet (WD) or WD+VitE (500IU/kg diet) ad lib starting at 8 or 20 weeks of age. All mice were studied at 28 weeks of age; thus, 5, 28 week-old MC4R-/- groups were investigated: chow, WD or WD+VitE for 20 weeks, and WD or WD+VitE for 8 weeks. This design allowed us to test whether VitE limits NASH pathogenesis after an intermediate or long exposure to WD. Mice (n=8-11, per group) underwent jugular vein and carotid artery catheterization for 13C/2H isotope-based metabolic flux analysis to calculate in vivo liver glucose and citric acid cycle fluxes. Body weight and fat mass were unaffected by WD or WD+VitE feeding for 8 weeks. 20 weeks of WD or WD+VitE, however, increased these parameters relative to chow. Glucose production, gluconeogenesis, and pyruvate cycle fluxes were also elevated by 20 weeks of WD or WD+VitE feeding. Unlike mice fed WD for 8 weeks, WD+VitE for 8 weeks also accelerated gluconeogenesis. All mice fed a WD or WD+VitE had increased hepatocellular steatosis, ballooning, lobular inflammation and activity compared to chow; fibrosis was more extensive in mice fed a WD or WD+VitE for 20 weeks. Thus, the provision of VitE during hyperphagia and WD failed to limit NASH pathogenesis. In fact, shorter term VitE supplementation accelerated WD-mediated changes in glucose production, indicating VitE may actually exacerbate the dysregulation of liver metabolism that occurs in response to chronic overnutrition.

Disclosure

C. Hasenour: None. J. Young: None.
Evaluation of Hepatic Steatosis and Fibrosis Using Transient Elastography in Partial Lipodystrophy Patients
Authors: DOS SANTOS FÁBIO F. , VIOLA LUIZ FELLIPE C. , MATSUURA FELIPE O. , VALERIO CYNTHIA M. , GODOY-MATOS AMELIO F. , COSTA MARCIA H. , ARAUJO-NETO JOAO M. , DIAS MELINA
Published: June 2018

Introduction: Partial lipodystrophy (PL) is a rare disease associated with insulin resistance and metabolic dysfunctions, including NAFLD. Global prevalence of NAFLD is ±25%. In PL patients NAFDL prevalence and severity remains unclear. AIMS To evaluate the presence of hepatic steatosis and/or fibrosis in PL patients using transient elastography (TE) in comparison to a control group.

Materials and Methods: Fifteen patients (7 with PL of the limbs, 8 with Familiar Partial Lipodystrophy Dunnigan-type) and 15 (13 women) controls paired to BMI and age were included. We recruited participants aged 18-65 years-old and a BMI≥25 and ≤35kg/m², excluding other causes of steatohepatitis. Anthropometric measures, metabolic parameters and the presence of steatosis/fibrosis using TE(Fibroscan®) were evaluated. According to literature, the adopted cut-off values in TE for Controlled Attenuation Parameter (CAP) and Liver Stiffness Measurement (LSM) are ≥238dB/m and ≥5,8kPa, respectively. Student t-test was used for continuous variables. Main results are presented as Mean ± SD.

Results: Mean age was 52.93 and 50.26 years-old in PL and control groups, respectively. BMI was slightly but not significantly higher in control group (30,13kg/m² [SD±2,85] vs. 27,43kg/m² [SD±5,30]). Waist-to-hip ratio did not differ. PL group had higher fasting plasma glucose (116.78mg/dL [SD±39,54] vs. 89,58mg/dL [SD±23,34], p= 0,0476). No differences in hepatic lesion biomarkers or lipid profile was noted, except for a lower HDL-c in PL group (40,64mg/dL [SD±9,45] vs. 49,62mg/dL [SD±12,67], p=0,0432). CAP tended to be higher in PL patients [301,82dB/m (SD±54,88) vs. 262,93dB/m (SD±57,44); p=0,0685] and LSM was significantly higher (7,32kPa [SD±3,71] vs. 4,94kPa [SD±1,58], p=0,0260).

Conclusions: Patients with PL presented a trend for increased hepatic steatosis and showed higher values of fibrosis in TE. Therefore, we suggest PL patients should undergo TE for screening of NAFLD.

Disclosure

L.C. Viola: None. F.O. Matsuura: None. C.M. Valerio: None. A.F. Godoy-Matos: Speaker's Bureau; Self; Novartis Pharmaceuticals Corporation. Other Relationship; Self; Takeda Development Center Americas, Inc., Novo Nordisk Inc.. M.H. Costa: None. J.M. Araujo-Neto: None. M. Dias: None.
Overall Safety of Canagliflozin (CANA) in the CANagliflozin CardioVascular Assessment Study (CANVAS) Program
Authors: HOLLANDER PRISCILLA , MOHAN VISWANATHAN , WOO VINCENT C. , WOO VINCENT C. , OH RICHARD , FULCHER GREG
Published: June 2018

CANA is an SGLT2 inhibitor that was generally well tolerated in 12 placebo (PBO) and active-controlled phase 3/4 trials (non-CANVAS studies [NCS]) for ≤104 weeks in a broad range of patients with type 2 diabetes (T2D). Here we report the longest-term safety data to date (up to 6.5 years) with CANA in patients with T2D and high CV risk from the CANVAS Program vs. the NCS. Amputation and fracture were novel safety signals in the CANVAS Program (HR [95% CI]: 1.97 [1.41, 2.75] and 1.26 [1.04, 1.52]) that were not seen in the NCS (RR [95% CI]: 0.23 [0.06, 0.89] and HR [95% CI]: 1.13 [0.74, 1.72]). The incidence of labeled AEs (i.e., osmotic diuresis [OD]- and volume depletion [VD]-related AEs, hypoglycemia, urinary tract infection, genital mycotic infection [GMI], renal-related AEs, hypersensitivity, diabetic ketoacidosis) and those that were serious or led to discontinuation in the CANVAS Program and the NCS are reported. In the CANVAS Program, incidence of OD- and VD-related AEs and GMI was higher with CANA vs. PBO, consistent with NCS (Table). There were no imbalances in other labeled AEs including hypoglycemia and renal-related AEs. The rate of serious and discontinuation-related labeled AEs was similar with CANA and PBO. CANA was generally well tolerated for up to 6.5 years in the CANVAS Program with an AE profile (excluding amputation and fracture) consistent with NCS, which included a more general T2D population.

Disclosure

P. Hollander: Advisory Panel; Self; Novo Nordisk Inc., Eli Lilly and Company, Merck & Co., Inc.. V. Mohan: None. V.C. Woo: Advisory Panel; Self; Janssen Pharmaceuticals, Inc., AstraZeneca, Novo Nordisk Inc., Sanofi, Boehringer Ingelheim Pharmaceuticals, Inc., Merck & Co., Inc. R. Oh: Employee; Self; Janssen Research & Development. G. Fulcher: Other Relationship; Self; Novo Nordisk Inc., Janssen Scientific Affairs, LLC., Boehringer Ingelheim GmbH, Merck Sharp & Dohme Corp..
Increased HbA1c Variability May Shorten Time to Microalbuminuria Development in Type 1 Diabetes (T1D)
Authors: CLEMENTS MARK A. , WU MENGDI , FOSTER NICOLE C. , LAFFEL LORI M. , SHAH VIRAL N. , VENDRAME FRANCESCO , KINGMAN RYAN S. , ALONSO GUY T. , CARLSON ANDERS , DESALVO DANIEL J. , BUCKINGHAM BRUCE A. , SHERR JENNIFER , BENJAMIN ROBERT , EYTH EMILY , DUBOSE STEPHANIE
Published: June 2018

We aim to understand the impact of HbA1c variability, as measured by SD-HbA1c, on risk of microalbuminuria in T1D population. An analysis was performed utilizing data of 8,680 participants in the T1D Exchange Clinic Registry (50% female, 86% non-Hispanic white, mean age 34 years, mean diabetes duration 14 years at enrollment) who met the following criteria: ≥2 clinic visit records, T1D duration ≥1 year at enrollment, age of diagnosis ≥10 years old and no known renal disease (including no microalbuminuria) at the time of registry enrollment. Median number of albuminuria and HbA1c measures were 4 and 21 per participant, respectively. Microalbuminuria was present during follow-up in 562 (6.5%) participants. Median intrapersonal mean HbA1c and SD-HbA1c were 7.8% and 0.6% respectively. Participants with high HbA1c variability had shorter time to first microalbuminuria (p<0.001, Figure 1a.) Those with high (≥50th percentile) mean HbA1c and high SD-HbA1c also had shorter diabetes duration prior to first reported microalbuminuria compared to high mean-HbA1c but low SD-HbA1c (p<0.001, Figure 1b). HbA1c variability relates to risk of microalbuminuria in T1D; its relationship to other outcomes should be studied.

Disclosure

M.A. Clements: Speaker's Bureau; Self; Medtronic. Advisory Panel; Self; Glooko, Inc.. M. Wu: None. N.C. Foster: None. L.M. Laffel: Consultant; Self; Eli Lilly and Company, Novo Nordisk Inc., Sanofi US, MannKind Corporation, Roche Diagnostics Corporation, Dexcom, Inc., Insulet Corporation, AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Johnson & Johnson Diabetes Institute, LLC.. V.N. Shah: None. F. Vendrame: Consultant; Self; Novo Nordisk Inc.. R.S. Kingman: None. G.T. Alonso: None. A. Carlson: Advisory Panel; Self; Sanofi, Insulet Corporation. Consultant; Self; Merck & Co., Inc.. Research Support; Self; Medtronic, Novo Nordisk A/S. D.J. DeSalvo: Consultant; Self; Dexcom, Inc.. Speaker's Bureau; Self; Insulet Corporation. B.A. Buckingham: Advisory Panel; Self; Novo Nordisk Inc., ConvaTec Inc.. Research Support; Self; Medtronic, Insulet Corporation, Dexcom, Inc., Tandem Diabetes Care, Inc.. Consultant; Self; Tandem Diabetes Care, Inc., Becton, Dickinson and Company. J. Sherr: Consultant; Self; Medtronic MiniMed, Inc.. Advisory Panel; Self; Insulet Corporation, Eli Lilly and Company, Bigfoot Biomedical. R. Benjamin: Speaker's Bureau; Self; Pfizer Inc.. E. Eyth: None. S. DuBose: None.
Beta-Cell Function and Survival Are Modulated Differentially by Type I or Type II Muscle through Specific Myokines
Authors: MIZGIER MARIA L. , RUTTI SABINE , PINGET MICHEL , BOUZAKRI KARIM
Published: June 2018

Type 2 diabetes has a complex pathophysiology implicating several organs as the adipose tissue the liver, the skeletal muscle and the pancreas. Tissue crosstalk is emerging as a determinant way to coordinate the different organs implicated in glucose homeostasis. Among the inter-organ communication factors, muscle-secreted myokines can modulate the function and survival of pancreatic beta-cells. We establish human primary in vitro models of cells isolated from soleus (type I), triceps brachii (type II) and vastus lateralis (mixte) muscles to study the myokines profile secretion using and antibody-based array, the transcriptome using RNA-sequencing, and their sensitivity to TNF-alpha-induced insulin resistance, by assessing the glucose uptake rate. We then investigate how the muscle type and insulin resistance status impact on beta-cell function (glucose stimulated insulin secretion), survival (proliferation and apoptose) in order to identify new myokines in fiber type specific muscle pancreas crosstalk. We show that type I and type II primary myotubes present specific mRNA and myokine signatures as well as different sensitivity to TNF-alpha induced insulin resistance (TNF-alpha failed to induce insulin resistance in type II muscle). We also report here that the impact of myokines on beta-cells proliferation, apoptosis and insulin secretion, depends on fiber types and their metabolic status. Finally, that angiogenin and osteoprotegerin are triceps specific myokines with beta-cell protective actions against proinflammatory cytokines. These results suggest that type I and II muscles could impact insulin secretion and beta-cell mass differentially in type 2 diabetes through specific myokines secretion.

Disclosure

M.L. Mizgier: None. S. Rutti: None. M. Pinget: None. K. Bouzakri: None.
Perivascular Adipose Tissue Controls Insulin-Stimulated Perfusion and Glucose Uptake in Muscle through Adipomuscular Microvascular Anastomoses
Authors: TURAIHI ALEXANDER H. , SERNE ERIK H. , MOLTHOFF CARLA , GOUMANS MARIE-JOSE T. , JIMENEZ CONNIE J. , YUDKIN JOHN S. , SMULDERS YVO M. , VAN HINSBERGH VICTOR W. , ERINGA ETTO C.
Published: June 2018

Insulin-mediated microvascular recruitment (IMVR) regulates delivery of insulin and glucose to insulin-sensitive tissues. We have previously proposed that perivascular adipose tissue (PVAT) controls glucose metabolism and vascular function through outside-to-inside communication and through vessel-to-vessel, or “vasocrine” signaling. Here, we studied this hypothesis in mice by examining effects of removal of local intramuscular PVAT on muscle blood flow and glucose metabolism. Using the hyperinsulinemic, euglycemic clamp (HEC) in combination with positron emission tomography, we found that local PVAT removal transiently reduces muscle glucose uptake by ±50 percent. Contrast-enhanced ultrasonography and intravital microscopy of the gracilis artery (GA) during the HEC showed that PVAT removal abolishes insulin-induced increases in GA diameter and abrogated insulin-stimulated muscle blood volume (microvascular recruitment or IMVR). The effect of PVAT on IMVR was mediated by distinct microvessels or anastomoses, which we showed using lightsheet microscopy of mice expressing mCherry in endothelial cells. Proteomics analysis revealed that PVAT removal significantly alters expression of 109 of 1719 detected proteins in muscle. Observed changes in protein expression included reduction of a mitochondrial protein cluster and of vesicle-associated membrane protein 5 (Vamp5), involved in Glut4 trafficking.

In conclusion, we have found that PVAT within muscle regulates muscle perfusion, glucose uptake and muscle protein expression, communicating with the distal microcirculation via microvascular anastomoses. These data highlight the importance of PVAT in vascular and metabolic physiology, and are relevant for type 2 diabetes and associated muscle dysfunction.

Disclosure

A.H. Turaihi: None. E.H. Serne: None. C. Molthoff: None. M.T. Goumans: None. C.J. Jimenez: None. J.S. Yudkin: None. Y.M. Smulders: None. V.W. van Hinsbergh: None. E.C. Eringa: None.
Adipsin Prevents Beta-Cell Failure in a Mouse Model of Type 2 Diabetes by Blocking Dedifferentiation and Cell Death
Authors: GOMEZ-BANOY NICOLAS , CHEN TONG , POIRIER BREANNE , RUBIO-NAVARRO ALFONSO , LO JAMES
Published: June 2018

Adipsin and its downstream molecule C3a are complement factors that regulate insulin secretion. In order to assess the effects of adipsin in chronic DM2 and beta cell failure, we used adeno-associated virus (AAV) to replenish adipsin in db/db mice. A robust increase in both serum adipsin and C3a was achieved using AAV-Adipsin compared to control AAV-GFP, even 5 months after the injection (Figure 1a). Adipsin treatment significantly ameliorated hyperglycemia and boosted insulin levels (Figure 1b). More importantly, adipsin treatment increased beta cell mass and prevented beta cell loss in the late stages of DM2 (Figure 1c). Mechanistically, adipsin decreased beta cell death and dedifferentiation (Figures 1d and e). Adipsin also augmented expression of key beta cell transcription factors. Using unbiased transcriptomics, we identified that adipsin treatment downregulated the phosphatase Dusp26 in the pancreatic islets. Interestingly, overexpression of Dusp26 in beta cells and primary islets leads to a loss of beta cell transcription factors and an increase in palmitate-induced cell death (Figures 1f and g). Pharmacological inhibition of Dusp26 increased islet survival in palmitate conditions. Collectively these data suggest that adipsin/C3a and dusp26 directed therapies may represent a novel approach to conserve beta cell mass and achieve long term beta cell health for patients with T2D.

Disclosure

N. Gomez-Banoy: None. B. Poirier: None. A. Rubio-Navarro: None. J. Lo: None.
BAF60a Orchestrates Thermogenic Chromatin Accessibility in Brown Fat
Authors: LI SIMING , LIU TONGYU , MI LIN , MENG ZHUOXIAN , LIN JIANDIE
Published: June 2018

Life Sciences Institute and Department of Cell and Developmental Biology, University of Michigan Medical Center, Ann Arbor, MI 48109

Brown fat thermogenesis is important for cold defense and systemic energy balance. The activation of the thermogenic gene program during development and in response to cold requires global reconfiguration of chromatin structure. Here we demonstrate that BAF60a, a component of SWI/SNF chromatin-remodeling complex, is indispensable for cold-induced thermogenesis. Mice with adipose tissue-specific inactivation of BAF60a exhibited impaired thermogenic gene expression and were exquisitely cold-sensitive. Assay for Transposase-Accessible Chromatin using sequencing (ATAC) revealed that chromatin accessibility of many brown fat-enriched genes was markedly reduced by Baf60a deficiency. Motif enrichment analysis indicated that these BAF60a-dependent chromatin regions are highly enriched for binding sites for PPARγ, EBF2, and C/EBPβ, key transcriptional regulators of thermogenic gene expression, suggesting that BAF60a likely serves an important role in orchestrating the thermogenic chromatin state. Adipose tissue inactivation of BAF60a augmented browning of inguinal adipose tissue following cold acclimation. Mechanistically, this browning response was linked to compensatory activation of the ACTH/Melanocortin 2 Receptor signaling. Our studies outline a mechanism of global control of chromatin accessibility during thermogenesis and reveal differential role of BAF60a in brown and beige fat biogenesis.

Disclosure

S. Li: None. T. Liu: None. L. Mi: None. Z. Meng: None. J. Lin: None.
Thiazolidinediones’ Insulin-Sensitizing Properties Depend on Adiponectin-Mediated Reductions in Certain Ceramide Species
Authors: GORDILLO RUTH , ZHANG KEHAO , SCHERER PHILIPP E. , HAWKINS MEREDITH
Published: June 2018

Adiponectin release from adipocytes is stimulated by the thiazolidinedione (TZD) class of PPARγ agonists in a time-dependent fashion, with an increase within 10 days followed by a more robust effect within 3 weeks. Our previous work suggested that adiponectin exerts its metabolic effects in part by enhancing the deacylation of the sphingolipid ceramide, a lipotoxic metabolite stimulated by exposure to saturated fats or inflammatory mediators. Adiponectin receptors in fact display potent ceramidase activity. Ceramides and diacylglycerols correlate with impaired insulin action. The effects of 10 and 21 days’ pioglitazone (Pio; 45 mg/day) treatment on insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp studies in n=26 type 2 diabetic subjects (Diabetes. 62:1843, 2013). Total and high molecular weight (HMW) adiponectin levels in plasma were determined using a commercial sandwich ELISA kit. Sphingolipids in adipose tissue and plasma were quantified by liquid chromatography-tandem mass spectrometry. Improved hepatic and peripheral insulin sensitivity was seen after 21 days, but not 10 days, of Pio, and were highly correlated with an increased ratio of HMW adiponectin/total levels (r2=0.90). Variable responses in both total and HMW adiponectin defined subjects as Responders (R;≥1.5-fold increase with Pio) vs. Non-responders (NR; no change). Sphingosine-1P, a beneficial conversion product from ceramides, increased 2-fold and Sphinganine-1P increased 2.5-fold in R relative to NR and placebo (p=0.0286). Pio induced decreases in dihydroceramides and increases in lactosylceramides as a function of time and adiponectin levels, the functional significance of which needs to be further explored. This study suggests the insulin-sensitizing properties of TZDs critically depend on elevating circulating adiponectin levels, with an associated lowering of certain ceramide species involved in insulin resistance and inflammation.

Disclosure

R. Gordillo: None. K. Zhang: None. P.E. Scherer: None.
Fibroblast Growth Factor-9 Regulates Adaptive Brown Adipose Tissue Mass Expansion
Authors: SHAMSI FARNAZ , HUANG TIAN LIAN , TSENG YU-HUA
Published: June 2018

Brown adipose tissue (BAT) plays an essential role in adaptive thermogenesis in response to environmental changes, such as cold and diet. Targeting BAT and modulating its mass and/or energy-dissipating capacity hold great promise for treatment of metabolic disorders. Expansion of BAT mass through increased cellular proliferation is a fundamental mechanism of cold adaptation. We have recently discovered Fibroblast Growth Factor 9 (FGF-9) as a cold-induced adipokine produced by BAT that regulates BAT mass. Adeno-associated virus (AAV)-mediated overexpression of FGF-9 in vivo increased BAT mass and improved glucose metabolism in obese mice. Additionally, using double thymidine analogue labeling we demonstrated that FGF-9 overexpression in BAT increased cellular proliferation and enhanced cold-induced BAT expansion. Using an adipose tissue-specific Cas9 knock-in mouse model coupled with the AAV-mediated delivery of gRNAs targeting FGF-9, we specifically deleted FGF-9 in BAT and demonstrated that loss of FGF-9 resulted in reduction of cold-induced proliferation of brown adipocyte progenitors, and led to impaired thermogenic capacity. Therefore, FGF-9 is essential for cold-induced formation of new brown adipocytes and long term cold adaptation. Combining the results from these gain- and loss-of-function studies, we conclude that FGF-9 acts as a growth factor for brown adipocyte progenitors to promote BAT expansion in response to cold. These findings provide a novel regulatory mechanism modulating BAT mass, and may ultimately contribute to the development of novel therapeutic strategies to combat obesity and its comorbidities.

Disclosure

F. Shamsi: None. T. Huang: None. Y. Tseng: Other Relationship; Self; Chugai Pharmaceutical Co., Ltd.. Research Support; Self; MedImmune.
Vitamin D Enhances Insulin Sensitivity in Neurons
Authors: TEIXEIRA SILVANIA , HE YANLIN , XU YONG , SISLEY STEPHANIE
Published: June 2018

Vitamin D deficiency has been linked to diabetes but a causal relationship is not clear. We previously published hypothalamic vitamin D action is critical for glucose tolerance and insulin sensitivity in obese animals. We hypothesized vitamin D also enhanced insulin sensitivity within the brain. Indeed, 48 hours of 1,25D3 (aka calcitriol) increased phosphorylation of Akt in hypothalamic cells (GT1-7). This effect was not observed in the absence of insulin, indicating that vitamin D was enhancing insulin action rather than mediating phosphorylation independently. Phosphorylation of Akt is often mediated by phosphoinositide 3-kinase (PI3K). Wortmannin, a PI3K inhibitor, blocked the effects of vitamin D to enhance pAkt. This supports a PI3K-dependent mechanism of vitamin D action. Vitamin D increased mRNA concentrations of key components of the PI3K/Akt pathway, namely IRS2 and p85. p55 expression, a negative regulator of PI3K, was decreased. Vitamin D did not affect transcription of the insulin receptor, IRS1, Akt, or the vitamin D receptor. Together, these support vitamin D as a regulator of the PI3K pathway in hypothalamic neurons. Additionally, the PI3K pathway has previously been shown to be important in rapid effects of other nuclear hormones. Since we previously published vitamin D depolarizes hypothalamic neurons, we investigated whether the PI3K pathway was also necessary in rapid vitamin D actions. Indeed, vitamin D was unable to depolarize hypothalamic neurons in the presence of the PI3K inhibitor wortmannin. Together, these data support that the action of vitamin D in the brain to influence glucose homeostasis may be through altered insulin signaling in the brain and requires the PI3K pathway for effects. These results are important in light of the known association between vitamin D and insulin resistance. They suggest that although vitamin D enhances insulin sensitivity, its actions are dependent upon a functional PI3K pathway, which is likely altered in an obese, insulin-resistant individual.

Disclosure

S. Teixeira: None. Y. He: None. Y. Xu: None. S. Sisley: Consultant; Self; Alexion Pharmaceuticals, Inc..
VEGF-A-Expressing Adipose Tissue Shows Rapid Beiging, Enhanced Survival after Transplantation
Authors: KIM MIN , AN YU A. , BANG HYUN SEOK , SCHERER PHILIPP E. , PARK JIYOUNG
Published: June 2018

Adipocyte-derived VEGF-A plays a crucial role in angiogenesis and contributes to adipocyte function and systemic metabolism, such as insulin resistance, chronic inflammation and beigeing of subcutaneous adipose tissue. Utilizing a doxycycline (Dox)-inducible adipocyte-specific VEGF-A overexpressing mouse model, we investigated the dynamics of local VEGF-A effects on tissue beiging of adipose tissue transplants. VEGF-A overexpression in adipocytes triggers angiogenesis. We also observe a rapid appearance of beige fat cells in subcutaneous white adipose tissue (sWATs) within as early as 2 days post induction of VEGF-A. In contrast to conventional cold-induced beiging, VEGF-A-induced beiging is independent of IL-4. We subjected metabolically healthy VEGF-A overexpressing adipose tissue to autologous transplantation. Transfer of subcutaneous adipose tissues taken from VEGF-A overexpressing mice into diet-induced obese mice resulted in systemic metabolic benefits, associated with improved survival of adipocytes and a concomitant reduced inflammatory response. These effects of VEGF-A are tissue autonomous, inducing WAT beigeing and angiogenesis within the transplanted tissue. Our findings indicate that manipulation of adipocyte functions with a bona fide angiogenic factor, such as VEGF-A, significantly improves the survival and volume retention of fat grafts and can convey metabolically favorable properties on the recipient on the basis of beiging.

Disclosure

M. Kim: None. Y.A. An: None. H. Bang: None. P.E. Scherer: None. J. Park: None.
p62 Deficiency Leads to Hypogonadism and Infertility via Pituitary Functions Loss in Young Female Mice before Metabolic Disorders Onset
Authors: LONG MIN , ZHENG HONGTING , LI XING
Published: June 2018

p62/SQSTM1 is an essential protein adaptor that fine-tunes numerous biological processes by autophagy or related cell signaling pathway. Previous studies have proved that p62 loss lead to mature-onset metabolic disorders including obesity, diabetes and fatty liver in adult mice; and in younger human being those metabolic diseases are close to reproductive dysfunctions, such as PCOS. Here, the metabolism and reproductive function of younger (8 weeks) p62 deficient female mice was observed, and hypothalamus-pituitary-ovary axis was evaluated to explore the possible upstream mechanisms. We found that although p62 deficiency rarely exposes obvious metabolic influences during younger stage of female mice, the deteriorative reproductive function has exhibited, such as attenuated breeding success rate and number of pups per litter. In particular, genetic deletion of p62 causes impaired estrous cycle, thread-like atrophied uteri and low-weight ovary with the lack of corpus luteum, failure of folliculogenesis and ovulation. Next, the low levels of plasma sex steroid hormone estradiol and gonadotropic luteinizing hormone (LH) have also been detected. Furthermore, defected steroidogenesis signaling including decreased StAR and P450scc in p62 KO ovary reveals reduced cholesterol-to-pregnenolone transition, meanwhile, increased Lhcgr mRNA expression in ovarian suggests a compensatory reaction. Consistent with lower serum LH level, significantly decreased mRNA expression of Lhb as well as slightly reduced Fshb also were found in the pituitary of p62 KO female mice. In addition, the elevated expression of Kiss1 mRNA in hypothalamus might discover the compensatory for pituitary function loss. Our findings support the vital role p62 of pituitary on reproductive function in younger individuals, and this effect might be the direct consequence rather than by metabolic disorders induced by p62 deficiency.

Disclosure

M. Long: None. H. Zheng: None. X. Li: None.
Ablation of Adipose CREB3L3 Protects Mice from Obesity-Induced Metabolic Dysfunction
Authors: MCCANN MAXIMILIAN A. , QIANG GUIFEN , GIL VICTORIA , KONG HYERIM WHANG , ZHANG KEZHONG , LIEW CHONG WEE
Published: June 2018

Metabolically healthy obesity (MHO) is a subtype of obesity where individuals lack the metabolic symptoms associated with obesity, despite being obese. Our lab has found that the fat-specific ablation of cyclic-AMP Responsive Element Binding Protein 3-like-3 (CREB3L3) creates a phenotype mimicking MHO in mice fed a high-fat diet (HFD). CREB3L3 is an ER-bound transcription factor that we have discovered to not only be expressed in adipose tissue, but selectively downregulated in obese subcutaneous fat from both mice and human patients. Subcutaneous fat is considered the more “metabolically-protective” subtype of white adipose tissue in obesity, so we hypothesized that this downregulation of CREB3L3 could contribute to the healthier phenotype of obese subcutaneous fat, and the ablation of this protein specifically in adipose tissue could be metabolically beneficial. We found that the fat-specific knockout (KO) of CREB3L3 significantly increased body weight and the mass of both the subcutaneous inguinal (iWAT) and visceral epididymal (eWAT) fat depots on HFD, as compared to wild type controls. However, the KO mice do not exhibit the insulin resistance or glucose intolerance expected with their more obese phenotype, likely due to enhanced lipid storage in adipose tissue, which sequesters lipids away from the circulation and liver. Indeed, the KO mice do not exhibit dyslipidemia and have reduced hepatic triglyceride content. The enhanced adipose lipid storage is achieved via the enlargement of the iWAT and eWAT in the KO mice. Morphometric analysis shows that both of these tissues have more adipocytes, and the eWAT has more large adipocytes. While adipocyte hypertrophy typically contributes to metabolic dysfunction, the KO eWAT, along with the iWAT, actually exhibit a reduction in inflammatory marker expression. This ability to reduce adipose inflammation while enhancing lipid storage capacity allows the CREB3L3 KO mice to gain more weight on HFD, yet maintain a healthy metabolic profile.

Disclosure

M.A. McCann: None. G. Qiang: None. V. Gil: None. H. Whang Kong: None. K. Zhang: None. C. LIew: None.
Androgens Activate Myeloid Cells during High-Fat Diet Exposure Promoting Sex Differences in Metabolic Disease
Authors: GRIFFIN CAMERON A. , ABRISHAMI SIMIN , VARGHESE MITA , SINGER KANAKADURGA
Published: June 2018

Men have a higher risk of metabolic and cardiovascular disease than pre-menopausal women, but the mechanisms of these differences are elusive. Chronic myeloid inflammation during obesity contributes to metabolic disease risk and is significantly more robust in males. Given the paucity of data on male sex hormones contributing to macrophage responses in obesity, our objective was to understand the role of androgens in promoting obesity-induced myeloid inflammation. Male and female C57Bl/6J mice were fed a 60% high fat diet for 24 weeks. Glucose tolerance and insulin sensitivity were measured. Monocyte transfer experiments assessed sex differences in bone marrow myeloid responses to obesity independent of host sex. Gonadectomy, mice deficient of androgen receptor signaling (ARtfm) and monocyte specific androgen receptor (AR) knockout mice (LysMAR-/y) were used to model androgen deficiency. Compared to males, females had dampened inflammatory responses with reduced CD11c+ ATMs and cytokines, even with increased adiposity. RNASeq demonstrated sex differences in gene pathways of both metabolic and inflammatory activation in ATMs. Male monocytes transferred into females remained primed for pro-inflammatory response and induced an increase in adiposity. Castrated males exposed to high fat diet had impaired glucose tolerance and increased insulin sensitivity with increased adiposity and lower numbers of CD11c+ ATMs. These same findings were seen in ARtfm mice. Testosterone enhanced palmitate-stimulated myeloid colony production, and this response was dampened in castrated, ARtfm, and LysMAR-/y mice. These studies demonstrate that androgens play a critical role in enhanced metabolic dysfunction and enhanced myeloid inflammation in response to obesogenic cues. Androgen driven myeloid inflammation leads to metabolic dysfunction in a cell-autonomous manner driving sex-differences in obesity induced meta-inflammation.

Disclosure

C.A. Griffin: None. S. Abrishami: None. M. Varghese: None. K. Singer: None.